JP2013170821A - Watch bearing unit, movement and watch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce resistance that a shaft body receives, in a bearing unit comprising a holder which holds each of spheres of a ball bearing.SOLUTION: A watch bearing unit comprises a shaft body 143 which is rotated around an axis and a bearing 181a which supports the shaft body in a rotatable manner. The bearing includes a plurality of spheres 183 disposed in a circumferential direction of the shaft body so as to be abutted to an outer circumferential surface of the shaft body, an outer ring 185 which holds the spheres with the shaft body, and a holder 189a including a body part 212a which is provided between the shaft body and the outer ring and holds the plurality of spheres mutually at fixed intervals. The body part has lightweight portions 204 which are provided at equal intervals in the circumferential direction around the shaft body and reduces a mass of the holder.

Description

  The present invention relates to a timepiece bearing unit, a movement, and a timepiece.

  Conventionally, a timepiece is provided with a bearing so as to include a rotating shaft end of a rotating mechanical part such as a gear used in the timepiece, and the rotating shaft is guided by the bearing to rotate. Is transmitted, and the balance, which is a governor, reciprocates, so that the time is recorded.

  Here, as a configuration of a conventional watch bearing, for example, a configuration as shown in FIG. 15 is known. FIG. 15 shows a cross section of a speed governor as a rotating machine part used in a timepiece.

  As shown in FIG. 15, the balance with hairspring 520 is rotatable around the center axis C at the small diameter shaft portions 521 and 522 at both ends by a watch bearing 510 formed along the center axis C on the balance 505 and the main plate 504. A supporting stem 523, an annular rim portion 524 forming a balance wheel body, and an arm portion 525 connected to both ends of the rim portion 524 and extending in the diameter direction of the rim portion 524 are provided, and an intermediate portion 526 of the arm portion 525 is provided. And a whistle ball 550 fixed to the central shaft portion 527 of the balance stem 523, and a swing seat 554 holding a swing stone 552.

  The watch bearing 510 is arranged in an outer bearing frame 512 held by the inner peripheral surface of the balance 505, an inner bearing frame 511 disposed in the outer bearing frame 512, and an inner diameter recess of the inner bearing frame 511. As a thrust bearing for the small-diameter shaft portion 522 of the balance stem 523, which is provided in a hole 514 that acts as a journal bearing for the small-diameter shaft portions 521 and 522 at both ends of the balance stem 523 and a large-diameter recess in the inner bearing frame 511. There is a working stone 515 and an elastic body (pressing spring) 516 that is locked in the groove of the outer bearing frame 512 and holds the stone 515 in the large-diameter recess of the inner bearing frame 511.

  By the way, in the conventional watch bearing 510 described above, in order to allow the rotation of the shaft, there is a gap between the shaft body (small diameter shaft portion 522) and the bearing (receiving stone 515, hole stone 514). is necessary. Agaki is a gap provided in the thrust direction (between the small-diameter shaft portion 522 and the stone 515), and play is a gap provided in the radial direction (between the small-diameter shaft portion 522 and the hole stone 514). It is. Due to the presence of the post and backlash, the contact position between the shaft and the bearings (the stone 515 and the hole stone 514) changes when the position of the watch changes or an impact is applied. Then, resistance due to friction between the shaft body (small-diameter shaft portion 522) and the bearings (bearing stone 515, hole stone 514) varies, and the swing angle varies, whereby the rate varies. As a result, there is a problem that the timekeeping accuracy of the watch deteriorates.

  Therefore, a configuration employing a ball bearing has been studied. The ball bearing includes a shaft and an outer ring having a rolling surface of a sphere, a plurality of spheres arranged along the circumferential direction between the shaft and the outer ring, a cage for keeping a constant pitch distance between the spheres, (For example, refer nonpatent literature 1). With the above-described configuration, the shaft body is rotatably supported.

  However, since the above-mentioned cage contacts the sphere when holding the sphere, rolling of the sphere is suppressed. Then, the rotation of the shaft supported by the rolling of the sphere also receives resistance, and the bearing loss increases. In particular, in the timepiece bearing, there is a problem that torque fluctuations in the power, the train wheel and the escapement, and fluctuations in the rotation cycle in the speed governor increase, and the timekeeping accuracy of the timepiece deteriorates.

Itomori, Hajimu, “Miniature Ball Bearing”, p. 7-13, (1961), Nikkan Kogyo Shimbun

  The present invention has been made in view of the above-described circumstances, and in a bearing unit including a cage that holds each sphere of a ball bearing, the resistance received by the shaft body is reduced, thereby improving the timing accuracy. The present invention provides a watch bearing unit, a movement, and a watch.

The present invention provides the following means in order to solve the above-described problems.
A timepiece bearing unit according to the present invention is a timepiece bearing unit having a shaft body that rotates about a shaft center and a bearing that rotatably supports the shaft body, and the bearing contacts the outer peripheral surface of the shaft body. Provided between a plurality of spheres that can be contacted along the circumferential direction of the shaft body, an outer ring that holds the spheres between the shaft bodies, and the shaft body and the outer ring. And a cage having a lightweight part that reduces the mass of the cage. The cage is provided at equal intervals in the circumferential direction around the shaft body.

  According to this configuration, since the moment of inertia of the cage is reduced by the lightweight portion, the resistance that the sphere receives when the sphere rolls decreases, and thus the resistance that the sphere gives to the shaft body decreases. Therefore, the resistance which a shaft body receives from a bearing at the time of rotation of a shaft body reduces. By reducing the bearing resistance, the balance angle of the balance is improved, and the effect of the escapement error is reduced by Airy's theorem, and the fluctuation of the rate can be reduced. Therefore, the timing accuracy of the movement can be improved.

  Moreover, the lightweight part of the timepiece bearing unit according to the present invention is formed by partially removing the body part.

  According to such a configuration, in addition to the above-described effects, the lightweight portion can be formed by a simple method, and deterioration of the bearing function due to deterioration in manufacturing accuracy when a complicated method is performed can be prevented. Also, in the timepiece assembly process, it is possible to grip the body part that has been partially removed when gripping the cage with a gripping tool, etc., so that it is possible to prevent damage to the sphere support part that requires surface precision. Thus, the shape accuracy of the bearing can be ensured.

  Moreover, the lightweight part of the timepiece bearing unit according to the present invention is constituted by a hollow part in which the body part is thinned.

  According to such a configuration, in addition to the above-described effects, the lightweight portion can be produced by a simple change of the molding die or a simple cutting process.

  Moreover, the light weight part of the timepiece bearing unit according to the present invention is constituted by a notch part obtained by partially cutting the body part.

  According to such a configuration, in addition to the above-described effects, the lightweight portion can be manufactured by simple processing.

  Moreover, the lightweight part of the timepiece bearing unit according to the present invention is constituted by a thin part in which the body part is partially thinned.

  According to such a configuration, in addition to the above-described effects, the lightweight portion can be produced by simple processing, and the strength of the cage can be maintained.

  Moreover, the lightweight part of the timepiece bearing unit according to the present invention is formed by partially lowering the body part.

  According to this configuration, in addition to the effects described above, the moment of inertia can be reduced while maintaining the strength of the cage.

  The material of the cage of the timepiece bearing unit according to the present invention is metal. In particular, the metal is any of mild steel, brass (brass), phosphor bronze, white, or stainless steel.

  According to such a configuration, in addition to the above-described effects, it is possible to perform processing such as cutting, forging, pressing, and (electric) casting, and it is possible to easily remove burrs after processing. As a result, the processing time can be shortened and the shape accuracy can be improved. When the shape accuracy is improved, it is possible to reduce the distance between the pitches of the spheres and the inclination of the cage with respect to the shaft body, thereby suppressing the bearing resistance fluctuations, reducing the balance angle fluctuation of the balance, and reducing the rate fluctuations. can do.

  The material of the cage of the timepiece bearing unit according to the present invention is resin. In particular, the resin is a synthetic resin typified by engineering plastics such as polyacetal or fluororesin, or a composite material such as glass fiber reinforced plastic or carbon fiber reinforced plastic.

  According to this configuration, in addition to the above-described effects, the cage can be further reduced in weight. When the cage is lighter, the moment of inertia of the cage is reduced, so the bearing resistance is reduced, the balance swing is improved, and fluctuations in the balance are also suppressed. Since the influence is reduced, the rate fluctuation is reduced.

  Furthermore, since the resin material has a smaller hardness than the metal material, the cage is less likely to damage the shaft or outer ring when the cage formed of the resin material contacts the shaft or outer ring formed of metal. Therefore, it is difficult for metal powder to be generated, and it is possible to reduce adverse effects such as damage to watch parts and ball rolling inhibition due to metal powder, improve component durability, and improve timing accuracy. it can.

  The material of the cage of the timepiece bearing unit according to the present invention is ceramics. In particular, the ceramic is any one of alumina such as ruby and sapphire, zircon, zirconia, forsterite, mullite, steatite, cordierite, silicon nitride, silicon carbide, or diamond.

  According to this configuration, in addition to the above-described effects, the cage can be further reduced in weight. When the cage is lighter, the moment of inertia of the cage is reduced, so the bearing resistance is reduced, the balance swing is improved, and fluctuations in the balance are also suppressed. Since the influence is reduced, the rate fluctuation is reduced. In addition, since ceramic materials have high hardness and excellent wear resistance, cages made of ceramics have little chipping and wear, and have excellent durability, so the life of the cage is extended. Therefore, troubles such as parts replacement can be reduced.

  The movement of the timepiece according to the present invention is a movement of a timepiece including a barrel, a watch wheel, a escape wheel, an ankle, and a balance with a timepiece bearing unit being used at least for the balance of the balance.

  The timepiece according to the present invention includes a movement and a casing that encloses the movement.

According to the timepiece bearing unit of the present invention, the moment of inertia of the cage can be reduced, and the bearing loss when the shaft body is in rotational contact with the bearing can be reduced.
According to the movement and timepiece of the present invention, the fluctuation of the rate can be reduced by improving the swing angle, and the movement and timepiece with high timing accuracy can be provided.

It is a top view of the movement front side of the mechanical timepiece in the first embodiment of the present invention. It is a general | schematic fragmentary sectional view which shows the part of the escape wheel from the barrel in 1st Embodiment of this invention. It is a general | schematic fragmentary sectional view which shows the part of the balance with the escape wheel in 1st Embodiment of this invention. (A) is a top view of the bearing unit in the first embodiment of the present invention. FIG. 4B is a sectional view taken along the cutting line Q-Q ′ in the top view of FIG. It is a perspective view of the holder | retainer in 1st Embodiment of this invention. (A) is a top view of the holder | retainer in 1st Embodiment of this invention. FIG. 6B is a sectional view taken along a cutting line A-A ′ in the top view of FIG. FIG. 10C is a sectional view taken along the cutting line B-B ′ in the top view of FIG. It is a perspective view of the holder | retainer in 2nd Embodiment of this invention. (A) is a top view of the cage in the second embodiment of the present invention. (B) is a cross-sectional view taken along section line D-D ′ in the top view of (a). (C) is sectional drawing in the cutting | disconnection line E-E 'in the top view of (a). It is a perspective view of the holder | retainer in 3rd Embodiment of this invention. (A) is a top view of the holder | retainer in 3rd Embodiment of this invention. FIG. 5B is a sectional view taken along the section line I-I ′ in the top view of FIG. (C) is sectional drawing in the cutting | disconnection line J-J 'in the top view of (a). It is a perspective view of the holder | retainer in 3rd Embodiment of this invention. (A) is a top view of the holder | retainer in 3rd Embodiment of this invention. FIG. 6B is a sectional view taken along the cutting line K-K ′ in the top view of FIG. FIG. 10C is a sectional view taken along a cutting line L-L ′ in the top view of FIG. It is a perspective view of the holder | retainer in 4th Embodiment of this invention. (A) is a top view of the holder | retainer in 4th Embodiment of this invention. FIG. 6B is a sectional view taken along a cutting line H-H ′ in the top view of FIG. FIG. 6C is a cross-sectional view taken along a cutting line G-G ′ in the top view of FIG. It is a general | schematic fragmentary sectional view which shows the structure of the balance with a balance as a conventional timepiece bearing unit.

(First embodiment)
A first embodiment of a timepiece bearing unit according to the present invention will be described with reference to FIGS.

(Mechanical watch)
First, a mechanical timepiece including the timepiece bearing unit of the present embodiment will be described. FIG. 1 is a plan view of the movement front side of a mechanical timepiece, FIG. 2 is a schematic partial sectional view showing a portion of a escape wheel from a barrel, and FIG. 3 is a schematic portion showing a portion of a balance wheel from the escape wheel. It is sectional drawing. In FIG. 1, some components are omitted, and the receiving member is indicated by a virtual line.

  As shown in FIGS. 1 to 3, the movement 100 of the mechanical timepiece has a base plate 102 that constitutes a substrate of the movement 100. A winding stem 110 is rotatably incorporated in the winding stem guide hole 102 a of the main plate 102. The dial 104 (see FIG. 2) is attached to the movement 100. In general, of both sides of the main plate 102, the side on which the dial plate 104 is disposed is referred to as the back side of the movement 100, and the opposite side of the side on which the dial plate 104 is disposed is referred to as the front side of the movement 100. A train wheel incorporated on the front side of the movement 100 is referred to as a front train wheel, and a train wheel incorporated on the back side of the movement 100 is referred to as a back train wheel. In addition, it is comprised as a portable timepiece by providing the movement 100 with a casing (not shown).

  The position of the winding stem 110 in the axial direction is determined by a switching device including the setting lever 190, the yoke 192, the yoke spring 194, and the back presser 196. The chisel wheel 112 is rotatably provided on the guide shaft portion of the winding stem 110. When the winding stem 110 is rotated in a state where the winding stem 110 is in the first winding stem position (0th stage) closest to the inside of the movement 100 along the rotation axis direction, the rotation of the handwheel is caused. The chic wheel 112 is rotated through. The round hole wheel 114 is rotated by the rotation of the chichi wheel 112. Further, the square hole wheel 116 is rotated by the rotation of the round hole wheel 114. As the square hole wheel 116 rotates, the mainspring 122 (see FIG. 2) accommodated in the barrel complete 120 is wound up.

  The center wheel & pinion 124 is rotated by the rotation of the barrel complete 120. The escape wheel & pinion 130 rotates through the rotation of the fourth wheel 128, the third wheel 126, and the second wheel 124. The barrel wheel 120, the second wheel 124, the third wheel 126, and the fourth wheel 128 constitute a front train wheel.

  The escapement and speed control device for controlling the rotation of the front train wheel includes a balance with hairspring 140, escape wheel 130, and ankle 142. Based on the rotation of the center wheel & pinion 124, the cylindrical pinion 150 (see FIG. 2) rotates simultaneously. The minute hand 152 attached to the cylindrical pinion 150 displays “minute”. The cylindrical pinion 150 is provided with a slip mechanism for the center wheel & pinion 124. Based on the rotation of the hour pinion 150, the hour wheel 154 rotates through the rotation of the minute wheel. An hour hand 156 attached to the hour wheel 154 displays “hour”.

  The barrel complete 120 includes a barrel complete gear 120d, a barrel complete 120f, and a mainspring 122. The barrel complete 120f includes an upper shaft portion 120a and a lower shaft portion 120b. The barrel complete 120f is made of a metal such as carbon steel. The barrel gear 120d is formed of a metal such as brass.

  The center wheel & pinion 124 includes an upper shaft portion 124a, a lower shaft portion 124b, a pinion portion 124c, a gear portion 124d, and an abacus ball portion 124h. The pinion portion 124c of the center wheel & pinion 124 is configured to mesh with the barrel gear 120d. The upper shaft portion 124a, the lower shaft portion 124b, and the abacus ball portion 124h are formed of a metal such as carbon steel. The gear portion 124d is formed of a metal such as nickel.

  The third wheel & pinion 126 includes an upper shaft portion 126a, a lower shaft portion 126b, a pinion portion 126c, and a gear portion 126d. The pinion 126c of the third wheel & pinion 126 is configured to mesh with the gear portion 124d.

  The fourth wheel & pinion 128 includes an upper shaft portion 128a, a lower shaft portion 128b, a pinion portion 128c, and a gear portion 128d. The pinion portion 128c of the fourth wheel & pinion 128 is configured to mesh with the gear portion 126d. The upper shaft portion 128a and the lower shaft portion 128b are formed of a metal such as carbon steel. The gear portion 128d is formed of a metal such as nickel.

  The escape wheel & pinion 130 includes an upper shaft portion 130a, a lower shaft portion 130b, a pinion portion 130c, and a gear portion 130d. The pinion 130c of the escape wheel & pinion 130 is configured to mesh with the gear portion 128d.

  The ankle 142 includes an ankle body 142d and an ankle true 142f. The ankle true 142f includes an upper shaft portion 142a and a lower shaft portion 142b.

  The barrel complete 120 is supported rotatably with respect to the main plate 102 and the barrel holder 160. That is, the upper shaft portion 120 a of the barrel complete 120 f is supported so as to be rotatable with respect to the barrel holder 160. The lower shaft part 120b of the barrel complete 120f is supported to be rotatable with respect to the main plate 102. The second wheel 124, the third wheel 126, the fourth wheel 128, and the escape wheel 130 are supported rotatably with respect to the main plate 102 and the train wheel bridge 162. That is, the upper shaft portion 124a of the center wheel & pinion 124, the upper shaft portion 126a of the third wheel & pinion 126, the upper shaft portion 128a of the fourth wheel & pinion 128, and the upper shaft portion 130a of the escape wheel & pinion 130 are And is rotatably supported. In addition, the lower shaft portion 124b of the center wheel 124, the lower shaft portion 126b of the third wheel 126, the lower shaft portion 128b of the fourth wheel 128, and the lower shaft portion 130b of the escape wheel 130 are defined with respect to the main plate 102. It is rotatably supported.

  The ankle 142 is rotatably supported with respect to the main plate 102 and the ankle receiver 164. That is, the upper shaft portion 142 a of the ankle 142 is supported so as to be rotatable with respect to the ankle receiver 164. The lower shaft portion 142b of the ankle 142 is rotatably supported with respect to the main plate 102.

  The bearing portion of the barrel holder 160 that rotatably supports the upper shaft portion 120a of the barrel complete 120f, the bearing portion of the train wheel ring 162 that rotatably supports the upper shaft portion 124a of the center wheel & pinion 124, and the third wheel & pinion 126 The bearing portion of the train wheel bridge 162 that rotatably supports the upper shaft portion 126a, the bearing portion of the train wheel bridge 162 that rotatably supports the upper shaft portion 128a of the fourth wheel & pinion 128, and the escape wheel 130 Lubricating oil is injected into the bearing portion of the train wheel bridge 162 that rotatably supports the upper shaft portion 130a and the bearing portion of the ankle receiver 164 that rotatably supports the upper shaft portion 142a of the ankle 142. Further, the bearing portion of the main plate 102 that rotatably supports the lower shaft portion 120b of the barrel complete 120f, the bearing portion of the main plate 102 that rotatably supports the lower shaft portion 124b of the center wheel & pinion 124, and the third wheel 126 A bearing portion of the main plate 102 that rotatably supports the lower shaft portion 126b, a bearing portion of the main plate 102 that rotatably supports the lower shaft portion 128b of the fourth wheel & pinion 128, and a lower shaft portion 130b of the escape wheel 130. Lubricating oil is injected into the bearing portion of the base plate 102 that is rotatably supported and the bearing portion of the base plate 102 that rotatably supports the lower shaft portion 142 b of the ankle 142. This lubricating oil is preferably a precision machine oil, particularly preferably a so-called watch oil.

  In order to improve the retention performance of the lubricating oil, the conical, cylindrical, or frustoconical oil sump is provided on each bearing portion of the main plate 102, the bearing portion of the barrel holder 160, and each bearing portion of the train wheel bridge 162. It is preferable to provide a part. Providing the oil reservoir can effectively prevent the oil from diffusing due to the surface tension of the lubricating oil. The main plate 102, the barrel holder 160, the train wheel bridge 162, and the ankle receiver 164 may be formed of metal such as brass, or may be formed of resin such as polycarbonate.

(Structure of balance)
Next, the structure of the balance of the present embodiment will be described. As shown in FIG. 3, the balance with hairspring 140 includes a balance stem 140 a, a hairspring 140 c, and a balance wheel 171.

  The hairspring 140c is a thin leaf spring having a spiral shape having a plurality of winding numbers. An inner end portion of the hairspring 140c is fixed to a hairball 140d fixed to the balance stem (shaft main body portion) 140a, and an outer end portion of the hairspring 140c is rotatably attached to the balance holder 167. It is fixed by screwing through a beard 170a attached to 170.

  The bearing 181a includes a shaft body 143 that rotates about the center axis C, a plurality of spherical bodies 183 that are arranged along the circumferential direction of the shaft body 143 so as to be in contact with the outer peripheral surface of the shaft body 143, and a shaft body. An outer ring 185 that holds the sphere 183 with the 143, and a cage 189a that is provided between the shaft body 143 and the outer ring 185, and has a body portion that holds the plurality of spheres 183 at regular intervals. The Note that the trunk portion has a sphere holding portion that holds a plurality of spheres 183. The outer ring 185 receives an urging force F by an elastic body (pressing spring) 182, and the outer periphery of the frame body 166 including the bearing 181 a is fixed to the balance holder 167. The slow / fast needle 168 is rotatably attached to the balance holder 167. Further, the balance with hairspring 140 is supported so as to be rotatable with respect to the main plate 102 and balance holder 167.

  Here, the balance with hairspring 140 is configured to be rotatable about the central axis C, and thin medium-diameter shaft portions 144 and 145 are formed at both ends of the shaft body 143 (the balance stem 140a). A thin small-diameter shaft portion 147 is formed at the end of the medium-diameter shaft portion 145 opposite to the whistle ball 140d. The lower (back side) medium-diameter shaft portion 144 is rotatably supported with respect to the main plate 102, and the upper (front-side) medium-diameter shaft portion 145 (small-diameter shaft portion 147) is rotatable with respect to the bearing 181a. It is supported by. The balance with hairspring 140 and the bearing 181a constitute a bearing unit (watch bearing unit) 105a.

  Next, the timepiece bearing unit will be described. In the following description, the direction (thrust direction) along the central axis C of the bearing unit 105a in FIG. 3 is referred to as “axial direction”, and the direction orthogonal to the central axis C (radial direction) is referred to as “radial direction”. The direction around the central axis C is defined as “circumferential direction”. In FIG. 3, the bearing 181 a is depicted only on the side of the medium diameter shaft portion 145 (small diameter shaft portion 147), which is one end portion (upper end portion) of the shaft body 143, but the bearing 181 a is provided at both ends of the shaft body 143. Also good. Further, regarding the shaft body 143, the direction where the balance holder 167 and the main plate 102 are provided is defined as the “outside” axial direction, and the direction provided with the balance wheel 171 is defined as the “inside” axial direction.

  As shown in FIG. 3, the bearing 181 a is provided in the bearing unit 105 a together with the shaft body 143, and has a medium diameter shaft portion 145 (small diameter shaft) that is one end portion (upper end portion) of the shaft body 143 that rotates about the central axis C. A bearing 181a that restricts axial and radial movement of the shaft body 143, an elastic body 182 that restricts axial movement of the bearing 181a, and includes the bearing 181a and the elastic body 182. Frame body 166.

  FIG. 4A is a top view of the bearing unit in the embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along the cutting line Q-Q ′ in the top view of FIG. FIG. 5 is a perspective view of the cage in the first embodiment of the present invention. 6A is a top view of the cage in the first embodiment of the present invention, and FIG. 6B is a cross-sectional view taken along the cutting line AA ′ in the top view of FIG. c) is a sectional view taken along a cutting line BB ′ in the top view of FIG.

  As shown in FIG. 3, the elastic body 182 is configured by a leaf spring member made of metal, for example. The elastic body 182 is supported and fixed on the outer side in the axial direction of the bearing 181 a in the frame body 166. The elastic body 182 has a biasing force F that biases the bearing 181a in the direction of the shaft body 143 (inward in the axial direction). In a state where no impact is applied to the bearing unit 105a, the biasing force F is applied to the bearing 181a. The spherical body 183 and the second support surface 206 provided on the medium diameter shaft portion 145 (small diameter shaft portion 147) are brought into contact with each other, and the shaft body 143 has an urging force capable of rotating around the central axis C. doing. That is, the elastic body 182 is configured as a pressurizing mechanism.

  The bearing 181a includes a plurality of (for example, four) spheres 183 arranged along the circumferential direction so as to be able to contact the second support surface 206 of the shaft body 143, and an outer ring that holds the sphere 183 in a rollable manner. 185 and a cage 189 a that is disposed along the circumferential direction of the second support surface 206 of the shaft body 143 and encloses the plurality of spheres 183.

  As shown in FIG. 4, the outer ring 185 is a member having a substantially disc-shaped outer shape and a substantially cylindrical or substantially conical inner surface, and a first portion penetrating along the axial direction in the radial center portion thereof. A through hole 186 is formed. The outer ring 185 has a shape in which a space in which the cage 189a, the sphere 183, and the small-diameter shaft portion 147 can be enclosed is provided inward. On the first inner peripheral surface 215 (second inner peripheral surface 216) of the first through hole 186, a first support surface 187 having a concave shape toward the radially outer side is formed along the circumferential direction. The 1st support surface 187 is formed in the curved surface shape which spreads toward the other end side (lower end side) from the axial direction one end side (upper end side). The outer ring 185 can be manufactured using a processing method such as cutting, forging, pressing, (electrical) casting, or molding.

  The medium-diameter shaft portion 145 is formed at one end portion of the shaft body 143 so as to protrude outward in the axial direction, and is formed as a concave surface from the end portion of the medium-diameter shaft portion 145 toward the radially inner side. A small-diameter shaft portion 147 with a small shaft diameter is provided via the surface 206.

  The spherical body 183 abuts on the first support surface 187 provided on the inner peripheral surface of the outer ring 185 and the second support surface 206 provided on the outer peripheral surface of the medium diameter shaft portion 145 (shaft body 143), respectively. It is held in a state of being included in a plurality of third through holes 205 provided in 189a. That is, the respective spheres 183 are arranged at equal intervals along the circumferential direction, and are held so as to freely roll. 3 and 4, the number of the spheres 183 is four. However, the number is not limited to this, and the number of the spheres 183 may be any number as long as it is three or more.

  The cage 189a includes a first guide surface 207a and a second guide surface 207b on the inner periphery, and a third guide surface 207c on the outer periphery. The small diameter shaft portion 147 includes a first outer peripheral surface 208 on the outer periphery. The medium diameter shaft portion 145 includes a second outer peripheral surface 203 on the outer periphery. The outer ring 185 includes a second inner peripheral surface 216 on the inner periphery. The first guide surface 207a and the first outer peripheral surface 208, the second guide surface 207b and the second outer peripheral surface 203, and the third guide surface 207c and the second inner peripheral surface 216 are arranged substantially parallel to each other, and Is provided with a gap for allowing rotation of the cage 189a and the medium diameter shaft portion 145 (small diameter shaft portion 147). The gap amount is desirably 1 μm to 20 μm. When the center line M of the cage 189a is about to change with respect to the center axis C, the first guide surface 207a and the first outer peripheral surface 208, the second guide surface 207b and the second outer peripheral surface 203, and the third guide surface 207c At least one of the second inner peripheral surfaces 216 abuts, and serves as a guide that suppresses the posture change of the cage 189a.

  5 and 6, the cage 189a is a rotationally symmetric member in which the third guide surface 207c is formed by a substantially inclined surface, and a second through-hole penetrating along the axial direction at the radial center portion thereof. 202 is formed. A medium diameter shaft portion 145 (small diameter shaft portion 147) is inserted into the second through hole 202. In addition, a plurality of third through holes 205 penetrating the body portion 212a from the third guide surface 207c to the second through hole 202 are formed at equal intervals along the circumferential direction to constitute a spherical body holding portion. Each third through-hole 205 contains a sphere 183. In addition, a gap is provided between the third through hole 205 and the sphere 183, and the sphere 183 is allowed to roll.

  The cage 189a includes a plurality of fourth through holes 204 that penetrate the body 212a from the third guide surface 207c to the second through hole 202. The fourth through hole 204 becomes a hollow portion as a lightweight portion that reduces the moment of inertia of the cage 189a. That is, the plurality of fourth through holes 204 that are lightweight portions are formed by partially removing the body portion 212a. In other words, the plurality of fourth through holes 204 that are lightweight portions are hollow portions in which the body portion 212a is thinned. The plurality of fourth through holes 204 are arranged symmetrically with respect to the center line M (equally spaced in the circumferential direction around the center line M). The plurality of fourth through holes 204 and the plurality of third through holes 205 are arranged in a well-balanced manner with a certain distance from each other so as to ensure the durability of the body portion 212a. For example, the center of the fourth through hole 204 and the center of the third through hole 205 are not arranged on the same cross section passing through the center line M. That is, the AA ′ cross section is a view cut along the center of the third through hole 205, and the BB ′ cross section is a view where the center of the fourth through hole 204 is cut. In the present embodiment, eight fourth through holes 204 are illustrated as an example. However, the number is not limited to this, and any number of the fourth through holes 204 may be provided as long as it is two or more. In addition, since it is sufficient that a part of the portion constituting the cage 189a has a light-weight portion, the portion that contacts the sphere 183 can also be provided with the fourth through hole 204.

  In addition, when the cage 189a is provided in the bearing unit, when the third guide surface 207c, which is the outer periphery of the cage 189a, is a slope, it is difficult to hold the cage 189a using the fourth through hole 204. Is possible. If the third through-hole 205 containing the sphere 183 is held, the inner surface of the third through-hole 205 may be damaged, the distance between the pitches of the sphere 183 may be shifted, and the timing accuracy may be deteriorated. , The cage 189a can be gripped while maintaining the distance between the pitches of the spheres 183 constant.

  3 and 4, in the bearing 181 a configured as described above, the shaft body 143 (medium-diameter shaft portion 145) usually rotates around the central axis C. At this time, since the spherical body 183 is arranged on the bearing 181a, the medium-diameter shaft portion 145 can smoothly rotate around the center line C.

  Further, the cage 189a and the fourth through-hole 204, which is a hollow portion as a lightweight portion, can be manufactured using a processing method such as cutting, forging, pressing, (electrical) casting, molding, or the like. . Specifically, in the case of deformation processing using a mold (mold, resin mold, etc.) for production, it can be formed by a single molding as a minimum number of times, and in the removal processing such as cutting, the body portion 212a is processed. Later, the fourth through-hole 204 can be easily manufactured by additional machining.

  As described above, in the present embodiment, the lightweight portion can be formed by a simple method, and the deterioration of the bearing function due to the deterioration of the manufacturing accuracy when a complicated method is applied can be prevented. For example, when a formation method more complicated than the formation method of the fourth through hole 204 is used, such as a through hole having a complicated shape, burrs are generated or the shape accuracy of the through hole is deteriorated, which is caused by the cage 189a. There is a risk that the bearing resistance increases. In this embodiment, these dangers can be avoided. Further, in the timepiece assembling process, since the barrel portion 212a partially removed when the holder is grasped by a gripping tool or the like can be gripped, the spherical support portion 205 that requires surface precision is damaged. Is suppressed, and the shape accuracy of the bearing can be ensured.

  Moreover, in this embodiment, since the holder | retainer 189a is equipped with the some 4th through-hole 204 which is a hollow part as a lightweight part, the weight of the holder | retainer 189a can reduce and an inertia moment can be reduced. Since the moment of inertia of the cage 189a is reduced, the energy required to rotate the cage 189a can be reduced, so that the bearing loss in the bearing 181a can be reduced. Therefore, the swing angle of the balance with hairspring 140 is improved.

  Here, there is an escapement error as one of the causes of deterioration of the timekeeping accuracy of the mechanical timepiece. The escapement error refers to a delay in the rotation period of the balance with hairspring 140 that occurs when the ankle 142 that constitutes the escapement transmits torque to the calculus 213 provided in the balance 140 that constitutes the governor. Say. Typically, the escapement error acts on the rotation angle of the balance with a balance between ± 13 ° of the vibration center, that is, an angle of a total of 26 °, and has an overall effect of delaying the rotation cycle. The angle at which the escapement error acts is 26 degrees regardless of the swing angle of the balance with hairspring 140. Ideally, the rotation period of the balance with hairspring 140 is constant regardless of the swing angle. Therefore, the larger the swing angle of the balance with hairspring 140, the smaller the influence of the escapement error that has a delay effect on the rotation period of the balance with hairspring 140. Therefore, in this embodiment, the influence of the escapement error is reduced, and the fluctuation of the rate can be reduced. Therefore, the timing accuracy of the movement 100 (portable watch) can be improved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 7 is a perspective view of a cage in the second embodiment of the present invention. FIG. 8A is a top view of the cage in the second embodiment of the present invention, and FIG. 8B is a cross-sectional view taken along the cutting line DD ′ in the top view of FIG. c) is a sectional view taken along a cutting line EE ′ in the top view of FIG. In the present embodiment, description of the same contents as in the first embodiment will be omitted.

  The cage 189b includes a plurality of notches 201 that are partially cut away from the body 212b by passing through the body 212b from the third guide surface 207c to the second through hole 202. The plurality of notches 201 are arranged symmetrically with respect to the center line M (equally spaced in the circumferential direction around the center line M). In the present embodiment, four cutout portions 201 are illustrated as an example, but the present invention is not limited thereto, and any number of two or more cutout portions 201 may be provided. In addition, since it is only necessary to provide the cutout portion 201 at a part of the portion constituting the cage 189b, the cutout portion 201 can also be provided at a portion that contacts the sphere 183.

  The cage 189b and the notch 201 can be manufactured by using a processing method such as cutting, forging, pressing, (electrical) casting, or molding.

  As described above, in the present embodiment, the lightweight portion can be formed by a simple method, and the deterioration of the bearing function due to the deterioration of the manufacturing accuracy when a complicated method is applied can be prevented. For example, when a more complicated formation method than the formation method of the notch portion 201 is used, such as a notch portion having a complicated shape, the occurrence of burrs or the deterioration of the shape accuracy of the notch portion occurs, and the cage 189b There is a risk that the resulting bearing resistance increases. Further, in the timepiece assembling process, it is possible to grip the barrel portion 212b that has been partially removed when the holder is gripped by a gripping tool or the like, which may damage the spherical support portion that requires surface precision. The shape accuracy of the bearing can be ensured. And the notch part 201 as a lightweight part can be produced by simple change of a molding die, and a lightweight part can be produced by simple processing.

  Moreover, in this embodiment, since the holder | retainer 189b is provided with the some notch part 201 as a lightweight part, the weight of the holder | retainer 189b can reduce and an inertia moment can be reduced. By reducing the moment of inertia of the cage 189b, the energy required to rotate the cage 189b can be reduced, so that the bearing loss in the bearing 181b can be reduced. Therefore, since the swing angle of the balance with hairspring 140 is improved, the influence of the escapement error is reduced by Airy's theorem, and the fluctuation of the rate can be reduced. Therefore, the timing accuracy of the movement 100 (portable watch) can be improved.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 9 is a perspective view of a cage in the third embodiment of the present invention. 10A is a top view of the cage in the third embodiment of the present invention, and FIG. 10B is a cross-sectional view taken along the cutting line II ′ in the top view of FIG. c) is a sectional view taken along a cutting line JJ ′ in the top view of FIG. In the present embodiment, description of the same contents as those in the first and second embodiments is omitted.

  The cage 189c includes a plurality of thin portions 209 in which the body portion 212c is partially thinned on the three guide surfaces 207c of the body portion 212c. The plurality of thin portions 209 are arranged symmetrically with respect to the center line M (equally spaced in the circumferential direction with the center line M as the center). In the present embodiment, eight thin-walled portions 209 are illustrated as an example, but the present invention is not limited to this, and there may be any number of two or more portions. Moreover, since the thin part 209 should just be provided in a part of site | part which comprises the holder | retainer 189c, the thin part 209 can also be provided in the site | part which contacts the spherical body 183. FIG.

  The cage 189c and the thin portion 209 can be manufactured by using a processing method such as cutting, forging, pressing, (electrical) casting, or molding.

  As described above, in the present embodiment, the lightweight portion can be formed by a simple method, and the deterioration of the bearing function due to the deterioration of the manufacturing accuracy when a complicated method is applied can be prevented. For example, in the case where a forming method more complicated than the forming method of the thin portion 209 is used, such as a thin portion having a complicated shape, the occurrence of burrs or the deterioration of the shape accuracy of the thin portion occurs, and the bearing caused by the cage 189c. There is a risk of increased resistance. Further, in the timepiece assembling process, it is possible to grip the barrel portion 212c that has been partially removed when the holder is gripped by a gripping tool or the like, which may damage the spherical support portion that requires surface precision. The shape accuracy of the bearing can be ensured. And the thin part 209 as a lightweight part can be produced by a simple change of the molding die, and the lightweight part can be produced by a simple process, and the strength of the cage 189c can be maintained.

  Moreover, in this embodiment, since the holder | retainer 189c is provided with the some thin part 209 as a lightweight part, the weight of the holder | retainer 189c can reduce and an inertia moment can be reduced. By reducing the moment of inertia of the cage 189c, the energy required to rotate the cage 189c can be reduced, so that the bearing loss in the bearing 181c can be reduced. Therefore, since the swing angle of the balance with the shaft body 143 is improved, the influence of the escapement error is reduced by the Airy theorem, and the fluctuation of the rate can be reduced. Therefore, the timing accuracy of the movement 100 (portable watch) can be improved.

  FIG. 11 is a perspective view of the cage in the third embodiment of the present invention. FIG. 12A is a top view of the cage in the third embodiment of the present invention, and FIG. 12B is a sectional view taken along the cutting line KK ′ in the top view of FIG. c) is a cross-sectional view taken along a cutting line LL ′ in the top view of FIG.

  As shown in FIGS. 11 and 12, since the thin portion 209 of the cage 189c is arranged symmetrically around the center line M (equally spaced around the center line M), it is annularly arranged in the circumferential direction. Also good. In the present embodiment, one thin portion 209 is illustrated as an example, but the number is not limited to this, and there may be any number. Moreover, since the thin part 209 should just be provided in a part of site | part which comprises the holder | retainer 189c, the thin part 209 can also be provided in the site | part which contacts the spherical body 183. FIG. It can also be provided on the second through hole 202 side.

  As described above, in the present embodiment, the lightweight portion can be formed by a simple method, and the deterioration of the bearing function due to the deterioration of the manufacturing accuracy when a complicated method is applied can be prevented. For example, in the case where a forming method more complicated than the forming method of the thin portion 209 is used, such as a thin portion having a complicated shape, the occurrence of burrs or the deterioration of the shape accuracy of the thin portion occurs, and the bearing caused by the cage 189c. There is a risk of increased resistance. Further, in the timepiece assembling process, it is possible to grip the barrel portion 212c that has been partially removed when the holder is gripped by a gripping tool or the like, which may damage the spherical support portion that requires surface precision. The shape accuracy of the bearing can be ensured. And the thin part 209 as a lightweight part can be produced by a simple change of the molding die, and the lightweight part can be produced by a simple process, and the strength of the cage 189c can be maintained.

  Moreover, in this embodiment, since the holder | retainer 189c is provided with the thin part 209, the weight of the holder | retainer 189c can reduce and an inertia moment can be reduced. By reducing the moment of inertia of the cage 189c, the energy required to rotate the cage 189c can be reduced, so that the bearing loss in the bearing 181c can be reduced. Therefore, since the swing angle of the balance with hairspring 140 is improved, the influence of the escapement error is reduced by Airy's theorem, and the fluctuation of the rate can be reduced. Therefore, the timing accuracy of the movement 100 (portable watch) can be improved.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. FIG. 13 is a perspective view of a cage in the fourth embodiment of the present invention. FIG. 14A is a top view of the cage in the fourth embodiment of the present invention, and FIG. 14B is a sectional view taken along the cutting line HH ′ in the top view of FIG. c) is a sectional view taken along a cutting line GG ′ in the top view of FIG. In the present embodiment, description of the same contents as those in the first to third embodiments is omitted.

  The cage 189d is constituted by a low density portion 210 in which a part of the body portion 212d constituting the cage 189d is made low density by partially removing the density of the body portion 212d, or is replaced with a low density member. The low density portions 210 are arranged symmetrically with respect to the center line M (equally spaced in the circumferential direction around the center line M). In the present embodiment, eight low density portions 210 are illustrated as an example, but the present invention is not limited to this, and there may be any number. Moreover, since the low density part 210 is arrange | positioned symmetrically around the centerline M (at equal intervals around the centerline M), you may arrange | position circularly in the circumferential direction. In addition, since the low density portion 210 only needs to be provided in a part of the portion constituting the cage 189d, the low density portion 210 can also be provided in the portion in contact with the sphere 183.

  The cage 189d and the low density portion 210 can be manufactured by using a processing method such as cutting, forging, pressing, (electrical) casting, or molding.

  As described above, in this embodiment, the cage 189d includes the low-density portion 210 as a lightweight portion, so that the weight of the cage 189d can be reduced and the moment of inertia can be reduced. By reducing the moment of inertia of the cage 189d, the energy required to rotate the cage 189d can be reduced, so that the bearing loss at the bearing 181d can be reduced. Therefore, since the swing angle of the balance with hairspring 140 is improved, the influence of the escapement error is reduced by Airy's theorem, and the fluctuation of the rate can be reduced. Therefore, the timing accuracy of the movement 100 (portable watch) can be improved.

  In the present embodiment, for example, in the case of reducing the weight of the cage, when the hollow portion is provided in the cage, the strength becomes insufficient. There is an advantage that can be achieved.

  Further, metal can be used for the material of the cages 189a, 189b, 189c, and 189d of the timepiece bearing unit in the first to fourth embodiments described above. In particular, the metal is any of mild steel, brass (brass), phosphor bronze, white, or stainless steel. Therefore, processing such as cutting, forging, pressing, and (electric) casting can be performed, and burr removal after processing can be easily performed. As a result, the processing time can be shortened and the shape accuracy can be improved. When the shape accuracy is improved, fluctuations in the pitch distance between the spheres and the inclination of the center line M of the cages 189a, 189b, 189c, and 189d with respect to the shaft can be reduced. The swing angle variation can be reduced and the rate variation can be reduced.

  Moreover, resin can be used for the material of the cages 189a, 189b, 189c, and 189d of the timepiece bearing unit in the first to fourth embodiments described above. In particular, the resin is a synthetic resin typified by engineering plastics such as polyacetal or fluororesin, or a composite material such as glass fiber reinforced plastic or carbon fiber reinforced plastic. Accordingly, the cages 189a, 189b, 189c, and 189d can be further reduced in weight. When the cage is lightened, the moment of inertia of the cage is reduced, so that the bearing resistance can be reduced, the balance angle of the balance with hairspring can be improved, and the rate variation can be reduced. Furthermore, since the resin material has a smaller hardness than the metal material, the cage is less likely to damage the shaft or outer ring when the cage formed of the resin material contacts the shaft or outer ring formed of metal. Therefore, it is difficult for metal powder to be generated, and it is possible to reduce adverse effects such as damage to watch parts and ball rolling inhibition due to metal powder, improve component durability, and improve timing accuracy. it can.

  Moreover, ceramics can be used for the material of the cages 189a, 189b, 189c, and 189d of the timepiece bearing unit in the first to fourth embodiments described above. In particular, the ceramic is any one of alumina such as ruby and sapphire, zircon, zirconia, forsterite, mullite, steatite, cordierite, silicon nitride, silicon carbide, or diamond. Accordingly, the cages 189a, 189b, 189c, and 189d can be further reduced in weight. When the cages 189a, 189b, 189c, and 189d are lightened, the moment of inertia of the cages 189a, 189b, 189c, and 189d is reduced. Can do. In addition, since ceramic materials have high hardness and excellent wear resistance, the cages 189a, 189b, 189c, and 189d made of ceramics have little chipping and wear and are excellent in durability, so they are used as cages. Since the service life can be extended, it is possible to reduce troubles such as parts replacement.

  In the above-described first to fourth embodiments, the balance with hairspring 140 and the bearing 181a constitute the bearing unit (watch bearing unit) 105a. Naturally, the bearings are constituted by the gears of other watch parts and the bearing 181a. Units can be configured.

  The technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. In other words, the configuration described in the above-described embodiment is merely an example, and can be changed as appropriate. Moreover, you may combine each embodiment mentioned above suitably. For example, the bearing of the speed governor has been described in the description of the bearing of the present embodiment, but the watch bearing unit of the present invention is not limited to the speed governor, but includes power, a train wheel, an escapement, and other shafts and bearings. It can apply to the rotation unit provided with.

105a Bearing unit 143 Shaft body 144, 145 Medium diameter shaft portion 147 Small diameter shaft portion 181a, 181b, 181c, 181d Bearing 183 Sphere 185 Outer ring 189a, 189b, 189c, 189d Cage 201 Notch portion 204 Fourth through hole (hollow portion )
205 3rd through-hole (sphere holding part)
209 Thin part 210 Low density part 212a Body

Claims (15)

A shaft that rotates about its axis;
A timepiece bearing unit having a bearing that rotatably supports the shaft body,
The bearing is
A plurality of spheres arranged along the circumferential direction of the shaft body so as to be able to contact the outer peripheral surface of the shaft body;
An outer ring that holds the sphere with the shaft,
A retainer provided between the shaft body and the outer ring and having a trunk portion that holds the plurality of spheres at a predetermined interval;
The trunk is
A timepiece bearing unit having light-weight portions that are provided at equal intervals in the circumferential direction around the shaft body and reduce the mass of the cage.   The timepiece bearing unit according to claim 1, wherein the lightweight portion is formed by partially removing the body portion.   The timepiece bearing unit according to claim 2, wherein the lightweight portion is configured by a hollow portion in which the body portion is thinned.   The timepiece bearing unit according to claim 2, wherein the lightweight portion is formed by a cutout portion obtained by partially cutting the body portion.   The timepiece bearing unit according to claim 2, wherein the lightweight portion is formed of a thin portion in which the body portion is partially thinned.   The timepiece bearing unit according to claim 2, wherein the lightweight portion is formed by partially lowering the body portion.   The timepiece bearing unit according to claim 1, wherein a material of the cage is a metal.   The timepiece bearing unit according to claim 7, wherein the metal is any one of mild steel, brass (brass), phosphor bronze, western white, or stainless steel.   The timepiece bearing unit according to claim 1, wherein a material of the cage is resin.   The timepiece bearing unit according to claim 9, wherein the resin is a synthetic resin.   The timepiece bearing unit according to claim 9, wherein the resin is a composite material.   The timepiece bearing unit according to claim 1, wherein a material of the cage is ceramics.   The timepiece bearing unit according to claim 12, wherein the ceramic is any one of alumina such as ruby and sapphire, zircon, zirconia, forsterite, mullite, steatite, cordierite, silicon nitride, silicon carbide, or diamond. A movement of a watch with a barrel, watch wheel, escape wheel, ankle and balance,
A movement in which the timepiece bearing unit according to any one of claims 1 to 6 is used at least for the balance of the balance with hairspring.   A timepiece comprising the movement according to claim 14 and a casing containing the movement.

Images