JP4793755B2 - Electric tool - Google Patents

Description

  The present invention relates to a power tool, and particularly to a power tool having a vibration damping mechanism.

  Conventionally, electric tools having a vibration damping mechanism have been proposed. For example, in an electric tool including a casing including a handle portion, a motor housing, and a gear housing connected to each other, the electric motor is housed in the motor housing. In the gear housing, there is provided a motion conversion mechanism that converts the rotational motion of the electric motor into a reciprocating motion in the same direction as the rotation shaft of the electric motor. A cylinder extending in the same direction as the rotating shaft of the electric motor is provided in the impact housing. A tool holding portion is provided on the tip side of the cylinder, and the tip tool is detachably attached.

  Further, the cylinder is provided with a piston slidably on its inner periphery. The piston is reciprocated along the inner circumference of the cylinder by the motion conversion mechanism. A striker is slidably provided on the inner periphery of the cylinder at the tip side in the cylinder. An air chamber is defined in the cylinder and between the piston and the striker. On the tip side of the striker, an intermediate element is slidably provided in the cylinder in the front-rear direction. The above-described tip tool is located on the tip side of the meson.

The rotational driving force of the electric motor is transmitted to the motion conversion mechanism, and the piston is reciprocated in the cylinder by the motion conversion mechanism. Due to the reciprocating motion of the piston, the pressure of the air in the air chamber repeatedly rises and falls, giving a striking force to the striker. The striking element moves forward and collides with the rear end of the intermediate element, and the striking force is transmitted to the tip tool via the intermediate element. Thereby, a work material is crushed (for example, refer to patent documents 1).
Japanese Patent Laying-Open No. 2005-040880

  However, in the power tool described above, vibration due to driving of the striker is generated, and the workability of the power tool is reduced due to the vibration.

  Accordingly, an object of the present invention is to provide an electric tool that reduces vibrations caused by driving of the striker and improves workability.

In order to achieve the above object, the present invention provides a motor having a rotating shaft, a rotating shaft driven by the rotation of the rotating shaft, a gear portion provided between the rotating shaft and the rotating shaft, A motor casing that houses the motor, and a motion conversion mechanism that drives by receiving the rotation of the rotating shaft, converts the rotational force of the rotating shaft into a reciprocating force along the axial direction of the rotating shaft, And a gear casing that houses the gear portion and the motion conversion mechanism, and has a weight that moves in the same direction as the reciprocating direction of the motion conversion mechanism. a dynamic vibration absorber for absorbing the applied vibration, and a dynamic vibration absorber casing for holding the animal vibration absorber, the motor casing, animal vibration reducer dexterity casing, and the gear casing,該回in this order It provides a power tool which is arranged in a straight line along the axial direction of the shaft.

  Here, it is preferable that the weight is located in the casing for the dynamic vibration absorber.

  Furthermore, it is preferable that a hole is formed in the weight, the central axis of the hole is positioned coaxially with the axis of the rotating shaft, and the hole is opposed to the rotating shaft.

  The dynamic vibration absorber further includes a weight support portion connected to the casing for the dynamic vibration absorber, and a plurality of connection portions provided at rotationally symmetric positions around the center of gravity of the weight. The support portion is preferably connected to the dynamic vibration absorber casing via the plurality of connection portions.

  Moreover, it is preferable that the gravity center position of the power tool and the gravity center position of the weight are located in the casing for the dynamic vibration absorber.

  The dynamic vibration absorber casing includes a first dynamic vibration absorber casing that holds a bearing portion for rotationally supporting the rotary shaft, and a second dynamic vibration absorber for the second dynamic vibration absorber sandwiched between the dynamic vibration absorber casing and the gear casing. A casing, the gear casing is provided on the second dynamic vibration absorber casing side of the first gear casing, the cylindrical first gear casing connected to the second dynamic vibration absorber casing, A second gear casing that divides a space defined by the second dynamic vibration absorber casing and a space defined by the first gear casing; and the rotation shaft is disposed in the second dynamic vibration absorber casing. A rotation transmission member is provided which has one end side engaged with the rotation shaft and the other end side engaged with the gear portion located in the first gear casing. Which is preferably rotatably supported by a bearing provided on the second gear casing.

  The dynamic vibration absorber has a connecting portion that is located on the outer periphery of the dynamic vibration absorber casing and is connected to the dynamic vibration absorber casing. The vibration amplitude of the weight is determined by the rotation of the dynamic vibration absorber casing. It is preferably larger than the axial width of the shaft.

  The dynamic vibration absorber casing is formed with a groove extending in the axial direction of the rotating shaft and engageable with the connecting portion, and the dynamic vibration absorber casing is sandwiched between the motor casing and the gear casing. In addition, it is preferable that the connecting portion is also sandwiched between the motor casing and the gear casing to position the dynamic vibration absorber in the axial direction.

Also, a cylinder housed in the gear casing and provided to extend in the same direction as the axial direction of the electric motor, a tool holding part that is provided on the tip side of the cylinder and holds the tip tool, and the motion conversion A piston driven by a mechanism and slidably provided on the inner periphery of the cylinder. The weight of the dynamic vibration absorber is the same as the reciprocating direction of the piston due to the reciprocating motion of the piston. It is preferable to reciprocate in the direction.

  According to the electric tool of claim 1, a dynamic vibration absorber that has a weight that moves in the same direction as the reciprocating direction of the motion conversion mechanism, absorbs vibration applied to the main body due to the movement of the weight, a motor casing, A dynamic vibration absorber casing for holding the dynamic vibration absorber is disposed between the gear casing and the gear casing. Therefore, it is possible to provide a power tool with reduced vibration and improved workability. Moreover, an electric tool can be provided by using the same motor casing and gear casing as the conventional electric tool which does not have a dynamic vibration absorber, and the electric power tool which has a dynamic vibration absorber can be provided cheaply.

  According to the electric tool of the second aspect, the motor casing, the dynamic vibration absorber casing, and the gear casing are arranged in this order in the axial direction of the rotary shaft, and the weight is located in the dynamic vibration absorber casing. Therefore, the radial dimension of the dynamic vibration absorber casing can be designed to be compact. That is, by providing the dynamic vibration absorber outside the casing for the dynamic vibration absorber, it is difficult to work on the wall and the like, and it is difficult to grip the casing for the dynamic vibration absorber and workability can be prevented from being lowered.

  According to the third aspect of the present invention, since the hole is formed in the weight, the center axis of the hole is positioned coaxially with the axis of the rotating shaft, and the hole is opposed to the rotating shaft. By effectively utilizing the space in the vibration absorber casing, it is possible to secure the mass required for the weight while suppressing an increase in the axial dimension of the rotary shaft of the power tool.

  According to the power tool of claim 4, the dynamic vibration absorber further includes a weight support portion connected to the dynamic vibration absorber casing, and a plurality of connection portions provided at rotationally symmetric positions around the center of gravity of the weight. And the weight support portion is connected to the dynamic vibration absorber casing via a plurality of connection portions. Therefore, no friction occurs between the weight support portion and the weight and the dynamic vibration absorber casing. The support portion and the weight can smoothly vibrate. Therefore, the vibration of the power tool can be effectively reduced, and the workability of the power tool can be improved. Further, since the connecting portions are provided at rotationally symmetric positions around the center of gravity of the weight, the weight can be reciprocated in parallel with the reciprocating motion direction. Therefore, the vibration of the power tool can be effectively reduced, and the workability of the power tool can be improved.

  According to the power tool of claim 5, since the center of gravity position of the power tool and the center of gravity position of the weight are located in the casing for the dynamic vibration absorber, the distance between the center of gravity position of the power tool and the center of gravity position of the weight is approach. Therefore, the moment generated during the reciprocating vibration of the weight can be reduced, and an electric tool with good workability can be provided.

  According to the power tool of claim 6, the second dynamic vibration absorber casing extends in the axial direction of the rotary shaft, one end side is engaged with the rotary shaft, and the other end side is located in the first gear casing. A rotation transmission member that engages with the gear portion is provided, and the rotation transmission member is rotatably supported by a bearing provided in the second gear casing. Therefore, in the conventional dynamic vibration absorber casing and the electric tool having no dynamic vibration absorber, the tip end portion of the rotary shaft is rotatably supported by the bearing. However, in the electric tool according to claim 6, the dynamic vibration absorber casing is provided. By providing, the distance between the motor and the gear portion increases. When the tip end portion of the rotating shaft is rotationally supported by the bearing as in the prior art, the length of the rotating shaft increases, the strength of the rotating shaft decreases, and the life is shortened early. Further, as the length of the rotating shaft increases, the rotating shaft tends to bend, and vibration due to rotation unbalance of the motor increases. In the electric tool according to the sixth aspect, by providing the rotation transmitting member in the dynamic vibration absorber casing, it is possible to provide an electric tool having a long life and low vibration.

  According to the electric tool of claim 7, the dynamic vibration absorber is located on the outer periphery of the dynamic vibration absorber casing and has a connecting portion connected to the dynamic vibration absorber casing, and the vibration amplitude of the weight is determined by the dynamic vibration absorption. It is comprised larger than the width | variety of the axial direction of the rotating shaft of the device casing. Therefore, the enlargement of the dimension of the axial direction of the rotating shaft of an electric tool can be suppressed.

  According to the power tool of claim 8, the dynamic vibration absorber casing is formed with a groove extending in the axial direction of the rotating shaft and engageable with the connecting portion, and the dynamic vibration absorber casing includes the motor casing and the gear casing. And the connecting portion is also sandwiched between the motor casing and the gear casing, and the dynamic vibration absorber is positioned in the axial direction. Therefore, the assembly workability of the electric tool can be improved. Furthermore, when the dynamic vibration absorber casing and the dynamic vibration absorber have an integral structure, the strength of the connecting portion is weak and may be damaged. However, since the dynamic vibration absorber casing and the dynamic vibration absorber are separated from each other and the connecting portion is sandwiched between the motor casing and the gear casing, the strength of the connecting portion in the axial direction can be improved. Furthermore, when there is damage or the like, the dynamic vibration absorber can be easily replaced.

According to the electric tool of claim 9, a cylinder housed in the gear casing and provided so as to extend in the same direction as the axial direction of the electric motor, and a tool provided on the tip side of the cylinder and holding the tip tool A holding unit and a piston driven by a motion conversion mechanism and slidably provided on the inner periphery of the cylinder; Reciprocates in the same direction. Therefore, it is possible to provide an electric tool that reduces the vibration generated due to the reciprocating motion of the piston and improves the workability.

  An impact tool 1 according to a first embodiment in which the electric tool of the present invention is applied to an impact tool will be described with reference to FIGS. 1 and 2. In the following description, the left side in FIG. 1 is the front end side of the impact tool 1 and the right side is the rear end side of the impact tool 1. The impact tool 1 includes a handle portion 10, a motor casing 20, a weight casing 30, and a gear casing 40 that are connected to each other to form a casing.

  A power cable 11 is attached to the handle portion 10 and a switch mechanism 12 is built therein. A trigger 13 that can be operated by a user is mechanically connected to the switch mechanism 12. The power cable 11 connects the switch mechanism 12 to an external power source (not shown) and operates the trigger 13 to switch between connection and disconnection of the switch mechanism 12 and the power source.

  The motor casing 20 is provided on the upper portion of the handle portion 10. The handle portion 10 and the motor casing 20 are integrally formed of plastic. An electric motor 21 is accommodated in the motor casing 20. The electric motor 21 includes an output shaft 22 and outputs a rotational driving force.

  The weight casing 30 is a resin molded product provided in front of the motor casing 20. The weight casing 30 includes a first weight casing 30A connected to the motor casing 20, and a second weight casing 30B connected to the gear casing 40 and having a cylindrical shape. A bearing 32A is provided in the first weight casing 30A. A first intermediate shaft 31 is disposed coaxially with the output shaft 22 in the second weight casing 30B and is rotatably supported by a bearing 32A and a bearing 32B described later. The rear end portion 31A of the first intermediate shaft 31 is engaged with the output shaft 22, and the rotation of the output shaft 22 is transmitted to the first intermediate shaft 31 via the rear end portion 31A. The distal end portion of the first intermediate shaft 31 is located in the gear casing 40, and the first gear 31B is provided. The output shaft 22 is rotatably supported by the bearing 32A through the rear end portion 31A.

  A counterweight mechanism 33 is disposed in the second weight casing 30B. As shown in FIG. 2, which is a cross-sectional view taken along the line II-II in FIG. 1, the counterweight mechanism 33 includes a pair of connection members 34, a pair of weight support members 35, a counterweight 36, a bolt 37, and the like. It has. The pair of connection members 34 are provided at both ends of the second weight housing 60B in the vertical direction. In other words, the pair of connecting members 34 are provided at rotationally symmetric positions around the center of gravity of the counterweight 36. The pair of weight support members 35 are configured by leaf springs. Further, the upper and lower end portions of the weight support member 35 are connected to the second weight casing 30B via the connection members 34, respectively.

  The counterweight 36 has a substantially circular cross section, and a shaft insertion hole 36a is formed at the center thereof. Further, the counterweight 36 is fixed to the weight support member 35 with bolts 37. Therefore, the counterweight 36 is supported at both ends by the pair of weight support members 35. The first intermediate shaft 31 is inserted through the shaft insertion hole 36a. Therefore, the shaft insertion hole 36 a faces the output shaft 22. Further, the center of gravity G of the impact tool 1 is located in the weight casing 30.

  The gear casing 40 is a resin molded product provided in front of the second weight casing 30B. The gear casing 40 is provided with a first gear casing 40A that is connected to the second weight casing 30B and forms a cylindrical shape, and a second gear casing 40B that partitions between the first gear casing 40A and the second weight casing 30B. . The bearing 32B is provided in the second gear casing 40B. The first gear casing 40A and the second gear casing 40B define a deceleration chamber 40a that is a mechanism chamber that houses a rotation transmission mechanism described later. In the first gear casing 40A, a second intermediate shaft 42 rotates in parallel with the output shaft 21 to the first gear casing 40A and the second gear casing 40B via bearings 42B and 42C around the axis. It is supported as possible. Further, a side handle 16 is provided in the vicinity of the tool holding portion 15 described later of the first gear casing 40A.

  A second gear 41 that meshes with the first gear 31B is coaxially fixed to the end portion of the second intermediate shaft 42 on the electric motor 21 side. A gear portion 42A is formed on the distal end side of the second intermediate shaft 42 and meshes with a third gear 43 described later. A cylinder 44 is provided in the first gear casing 40 </ b> A and above the second intermediate shaft 42. The cylinder 44 extends parallel to the second intermediate shaft 42 and is rotatably supported by the second gear casing 40B. The third gear 43 is fixed to the outer periphery of the cylinder 44, and the cylinder 44 can rotate about its axis by meshing with the gear portion 42A described above.

  The tool holding portion 15 described above is provided on the tip side of the cylinder 44, and a tip tool (not shown) is detachably attached. A clutch 46 urged in the direction of the electric motor 21 by a spring is spline-engaged with an intermediate portion of the second intermediate shaft 42, and the clutch 46 is moved by a change lever 47 provided at the lower portion of the first gear casing 40A. It is possible to switch between hammer drill mode (position shown) and drill mode (position where the clutch 46 has moved in the distal direction). On the side of the electric motor 21 of the clutch 46, a motion conversion unit 50 that converts the rotational motion into a reciprocating motion is rotatably mounted on the second intermediate shaft 42. The arm portion 50 </ b> A of the motion conversion unit 50 is provided so as to be able to reciprocate in the front-rear direction of the impact tool 1 by the rotation of the second intermediate shaft 42.

  When the clutch 46 is switched to the hammer drill mode by the change lever 47, the second intermediate shaft 42 and the motion conversion unit 50 are coupled by the clutch 46, and the motion conversion unit 50 includes the piston pin 51. And is connected so as to interlock with a piston 52 provided in the cylinder 44. The piston 52 is mounted so as to reciprocate in a direction parallel to the second intermediate shaft 42 and to be slidable in the cylinder 44. A striking element 53 is housed in the piston 52, and an air chamber 54 is defined between the piston 52 and the striking element 53 in the cylinder 44. At a position opposite to the air chamber side of the striker 53, an intermediate element 55 is supported in the cylinder 44 so as to be slidable in the direction of movement of the piston 52. A tip tool (not shown) is located at a position opposite to the striker side of the intermediate piece 55. Therefore, the striker 53 strikes a tip tool (not shown) via the intermediate piece 55.

  A rotation output of a motor (not shown) is transmitted to the second intermediate shaft 42 via the first intermediate shaft 31, the first gear 31 </ b> B, and the second gear 41. The rotation of the second intermediate shaft 42 is transmitted to the cylinder 44 by meshing between the gear portion 42A and the third gear 43 that is externally mounted on the cylinder 44, and the rotational force is transmitted to a tip tool (not shown). When the clutch 46 is moved to the hammer drill mode by operating the change lever 47, the clutch 46 is coupled to the motion conversion unit 50, and the rotational driving force of the second intermediate shaft 42 is transmitted to the motion conversion unit 50. In the motion converter 50, the rotational driving force is converted into the reciprocating motion of the piston 52 via the piston pin 51. The pressure of the air in the air chamber 54 defined between the striking element 53 and the piston 52 by the reciprocating motion of the piston 52 repeatedly rises and falls, giving a striking force to the striking element 53. The striker 53 moves forward and collides with the rear end surface of the intermediate element 55, and the impact force is transmitted to the tip tool (not shown) via the intermediate element 55. In this manner, in the hammer drill mode, a rotational force and a striking force are simultaneously applied to a tip tool (not shown).

  When the clutch 46 is in the drill mode, the clutch 46 disconnects the connection between the second intermediate shaft 42 and the motion conversion unit 50, and only the rotational driving force of the second intermediate shaft 42 passes through the gear portion 42 </ b> A and the third gear 43. To the cylinder 44. Therefore, only the rotational force is applied to the tip tool (not shown).

  In the operation of the impact tool 1 of the present embodiment, vibration due to the reciprocating motion of the impactor 53 is generated. This vibration is transmitted to the connection member 34 via the second weight casing 30B. The vibration transmitted to the connection member 34 is transmitted to the weight support member 35 and the counter weight 36, and the counter weight 36 vibrates in the same direction as the reciprocating direction of the piston 52. This vibration can reduce the vibration of the striking tool 1 due to the reciprocating motion of the striking element 53 and can improve the workability of the striking tool 1.

  Further, as described above, the weight casing 30 is disposed between the motor casing 20 and the gear casing 40, and the counter weight mechanism 33 is provided in the weight casing 30. Therefore, the impact tool 1 can be provided by using the same motor casing and gear casing as the conventional impact tool not having the counterweight mechanism 33, and the impact tool 1 having the counterweight mechanism 33 can be provided at a low cost. Can do. Further, since the counterweight mechanism 33 is disposed in the second weight casing 30B, the radial dimension of the cylindrical second weight casing 30B can be designed to be compact. That is, by providing the counterweight mechanism 33 outside the weight casing 30, it is difficult to work on the wall, and it is difficult to grip the weight casing 30 and to prevent the workability from being lowered.

  The counterweight 36 has a shaft insertion hole 36a, and the first intermediate shaft 31 is inserted through the shaft insertion hole 36a. Therefore, it is possible to ensure the mass required for the counterweight 36 while effectively utilizing the space in the weight casing 30 and suppressing an increase in the size of the impact tool 1 in the longitudinal direction. Further, as described above, the counterweight mechanism 33 includes the connection member 34, the weight support member 35, and the counterweight 36. Therefore, no friction is generated between the weight support member 35 and the counterweight 36, which are leaf springs, and the weight casing 30. It can be done smoothly. Therefore, the vibration of the impact tool 1 due to the reciprocating motion of the piston 52 can be effectively reduced, and the workability of the impact tool 1 can be improved. Further, since the pair of connecting members 34 are provided at rotationally symmetric positions around the center of gravity of the counterweight 36, the counterweight 36 can be reciprocated in parallel with the reciprocating direction of the piston 52. Therefore, the vibration of the impact tool 1 due to the reciprocating motion of the piston 52 can be effectively reduced, and the workability of the impact tool 1 can be improved.

  Further, a first intermediate shaft 31 is provided in the weight casing 30, and the first intermediate shaft 31 is rotatably supported by a bearing 32A provided in the first weight casing 30A and a bearing 32B provided in the second gear casing 40B. . In the hitting tool that does not have the conventional weight casing 30 and the counterweight mechanism 33, the tip end portion of the output shaft 22 is rotatably supported by the bearing 32B. In the present embodiment, providing the weight casing 30 increases the distance between the electric motor 21 and the second gear 41. When the tip end portion of the output shaft 22 is rotationally supported by the bearing 32B as in the prior art, the length of the output shaft 22 increases, the strength of the output shaft 22 decreases, and the service life is shortened early. Furthermore, as the length of the output shaft 22 increases, the output shaft 22 is easily bent, and vibration due to rotational unbalance of the electric motor 21 increases. In the present embodiment, by providing the first intermediate shaft 31 in the weight casing 30, it is possible to provide the impact tool 1 having a long life and low vibration.

  Further, the gravity center position G of the impact tool 1 and the gravity center position of the counterweight 36 are set in the weight casing 30. Therefore, since the distance between the gravity center position G of the impact tool 1 and the gravity center position of the counterweight 36 approaches, the moment generated when the counterweight 36 reciprocates can be reduced, and the impact tool 1 with good workability is provided. can do.

  Next, an impact tool 101 according to a second embodiment in which the electric tool of the present invention is applied to an impact tool will be described with reference to FIGS. 3 and 4. The same members as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different portions are described.

  The counterweight mechanism 133 includes a support member 134, two springs 135, and a counterweight 136. The support member 134 has a cylindrical shape and extends in the axial direction of the output shaft 22. Both ends of the support member 134 are supported by the second gear casing 40B and the first weight casing 30A, respectively. The first intermediate shaft 31 is located in the hollow portion of the support member 134. On the outer periphery of the support member 134, a counterweight 136 is disposed so as to be slidable with respect to the support member 134. The counterweight 136 is formed with a support portion through hole 136a, and the support member 134 passes through the support portion through hole 136a. One of the two springs 135 is interposed between the counterweight 136 and the first weight casing 30A on the rear end side of the counterweight 136. The other spring 135 is interposed between the counterweight 136 and the second gear casing 40B on the distal end side of the counterweight 136.

  Also in the impact tool 101 of the present embodiment, the vibration caused by the reciprocating motion of the impactor 53 is transmitted to the spring 135 and the counter weight 136 via the first weight casing 30A and the second gear casing 40B, and the counter weight 136 vibrates in the same direction as the reciprocating direction of the piston 52. This vibration can reduce the vibration of the striking tool 101 caused by the reciprocating motion of the striking element 53, and can improve the workability of the striking tool 101. Moreover, the other effect of the impact tool 101 of this Embodiment is the same as that of the impact tool 1 of 1st Embodiment.

  Next, an impact tool 201 according to a third embodiment in which the electric tool of the present invention is applied to an impact tool will be described with reference to FIGS. 5 and 6. The same members as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different portions are described.

  As shown in FIG. 6, a groove 30 c extending in parallel with the axial direction of the first intermediate shaft 31 is formed on the side of the weight casing 30 from one end to the other end in the axial direction of the weight casing 30. Two counterweight mechanisms 233 are provided on the side of the weight casing 30. The counterweight mechanism 233 has a housing 233A, and two springs 235 (only one is shown) and a counterweight 236 are arranged in the housing 233A. Two springs 235 are arranged at both front and rear ends of the counterweight 236, respectively. Further, the counterweight 236 is provided in the housing 233A so as to be vibrated by the biasing force of the spring 235, and the amplitude of the vibration is configured to be larger than the width of the weight casing 30 in the axial direction of the output shaft 22. .

  The housing 233A has a connecting portion 237, and the connecting portion 237 is fitted in the groove portion 30c. When the weight casing 30 is sandwiched between the motor casing 20 and the gear casing 40, the connecting portion 237 is also sandwiched between the motor casing 20 and the gear casing 40. As a result, the housing 233A is positioned, and thus the counterweight mechanism 233 is positioned.

  Also in the impact tool 201 of the present embodiment, vibration due to the reciprocating motion of the impactor 53 is transmitted to the spring 235 and the counterweight 236 via the weight casing 30 and the housing 233A. Vibrates in the same direction as the reciprocating motion direction. This vibration can reduce the vibration of the striking tool 201 due to the reciprocating motion of the striking element 53, and can improve the workability of the striking tool 201. Further, by providing the counter weight mechanism 233 on the side of the weight casing 30, it is possible to suppress an increase in the size of the impact tool 201 in the longitudinal direction.

  Further, as described above, the counter weight mechanism 233 is positioned by fitting the connecting portion 237 into the groove portion 30c and sandwiching the weight casing 30 between the motor casing 20 and the gear casing 40. Therefore, the assembly workability of the impact tool 201 can be improved. Furthermore, when the weight casing 30 and the counter weight mechanism 233 (weight housing 233A) are integrated, the strength of the connecting portion is weak and may be damaged. However, since the weight casing 30 and the counterweight mechanism 233 (weight housing 233A) are separated from each other and the connecting portion 237 is in contact with the end surfaces of the motor casing 20 and the gear casing 40, the length of the impact tool 201 in the connecting portion 237 is reduced. Directional strength can be improved. Furthermore, the counterweight mechanism 233 can be easily replaced when there is damage or the like. Moreover, the other effect of the impact tool 201 of this Embodiment is the same as the effect of the impact tool 1 of 1st Embodiment.

  In addition, the impact tool of this invention is not limited to embodiment mentioned above, A various deformation | transformation and improvement are possible in the range described in the claim. For example, in the striking tool 1 of the first embodiment, two connection members 34 are provided at both ends in the vertical direction of the second weight casing 30B. However, three or more connection members 34 may be provided as long as they are rotationally symmetric positions. . In this case, the number of weight support members 35 corresponding to the number of connection portions 34 is provided. Moreover, in said embodiment, although the electric tool of this invention was applied to the impact tool, you may apply to a saver saw.

Sectional drawing of 1st Embodiment which applied the electric tool of this invention to the impact tool. Sectional drawing along the II-II line of FIG. Sectional drawing of 2nd Embodiment which applied the electric tool of this invention to the impact tool. Sectional drawing along the IV-IV line of FIG. Sectional drawing of 3rd Embodiment which applied the electric tool of this invention to the impact tool. Sectional drawing of the weight casing and counterweight mechanism of 3rd Embodiment which applied the electric tool of this invention to the impact tool.

Explanation of symbols

1, 101, 201 Impact tool, 15 Tool holder, 20 Motor casing, 21 Electric motor, 22 Output shaft, 30 Weight casing, 30A First weight casing, 30B Second weight casing, 30c Groove, 31 First intermediate shaft, 31B 1st gear, 32A, 32B Bearing, 33, 133, 233 Counter weight mechanism, 34 Connection member, 35 Weight support member, 36, 136, 236 Counter weight, 36a Shaft insertion hole, 37 bolt, 40 Gear casing, 40A 1st gear 1 gear casing, 40B second gear casing, 41 second gear, 42 second intermediate shaft, 44 cylinders, 50 motion conversion section, 50A arm section, 51 piston Down, 52 piston, 54 striker, 134 support member, 135, 235 spring, 136a support part through hole, 233A housing, 237 connection portion, G the center of gravity position

Claims (9)

A motor having a rotating shaft;
A rotating shaft that receives and rotates the rotating shaft;
A gear portion provided between the rotating shaft and the rotating shaft;
A motion conversion mechanism that drives by receiving the rotation of the rotating shaft, converts the rotational force of the rotating shaft into a reciprocating motion force along the axial direction of the rotating shaft, and reciprocates the reciprocating member;
A motor casing for housing the motor;
An electric tool having the gear portion and a gear casing that houses the motion conversion mechanism,
A dynamic vibration absorber having a weight that moves in the same direction as the reciprocating direction of the motion conversion mechanism, and that absorbs vibration applied to the main body by the movement of the weight;
A dynamic vibration absorber casing for holding the dynamic vibration absorber ;
The electric tool characterized in that the motor casing, the dynamic vibration absorber casing, and the gear casing are arranged linearly in this order along the axial direction of the rotary shaft .   The power tool according to claim 1, wherein the weight is located in the casing for the dynamic vibration absorber.   3. The weight according to claim 2, wherein a hole is formed in the weight, a central axis of the hole is coaxial with an axis of the rotating shaft, and the hole is opposed to the rotating shaft. Power tools. The dynamic vibration absorber further includes a weight support portion connected to the casing for the dynamic vibration absorber, and a plurality of connection portions provided at rotationally symmetric positions around the center of gravity of the weight,
4. The electric tool according to claim 2, wherein the weight support portion is connected to the dynamic vibration absorber casing through the plurality of connection portions.   The electric power tool according to any one of claims 1 to 4, wherein the center of gravity position of the power tool and the center of gravity of the weight are located in the casing for the dynamic vibration absorber. The dynamic vibration absorber casing includes a first dynamic vibration absorber casing that holds a bearing portion for rotatably supporting the rotary shaft, and a second dynamic vibration absorber casing that is sandwiched between the dynamic vibration absorber casing and the gear casing. Have
The gear casing is provided on a cylindrical first gear casing connected to the second dynamic vibration absorber casing, and on the second dynamic vibration absorber casing side of the first gear casing, and the second dynamic vibration absorber casing is provided. A second gear casing that partitions a space defined by the first gear casing and a space defined by the first gear casing;
In the casing for the second dynamic vibration absorber, the rotation extends in the axial direction of the rotary shaft, one end side engages with the rotary shaft, and the other end side engages with the gear portion located in the first gear casing. The transmission member is provided, and the rotation transmission member is rotatably supported by a bearing provided in the second gear casing. Electric tool. The dynamic vibration absorber is located on an outer periphery of the dynamic vibration absorber casing and has a connecting portion connected to the dynamic vibration absorber casing;
The power tool according to claim 1, wherein an amplitude of vibration of the weight is larger than an axial width of the rotary shaft of the casing for the dynamic vibration absorber. The dynamic vibration absorber casing is formed with a groove extending in the axial direction of the rotating shaft and engageable with the connecting portion,
When the casing for the dynamic vibration absorber is sandwiched between the motor casing and the gear casing, the connecting portion is also sandwiched between the motor casing and the gear casing, so that the dynamic vibration absorber is positioned in the axial direction. The power tool according to claim 7, wherein A cylinder housed in the gear casing and provided to extend in the same direction as the axial direction of the electric motor;
A tool holding portion that is provided on the tip side of the cylinder and holds the tip tool;
A piston driven by the motion conversion mechanism and slidably provided on the inner periphery of the cylinder;
The weights of the animals vibration absorber, according to any one of claims 1 to 8, characterized in that due to the reciprocating motion of the piston reciprocating in the reciprocating direction the same direction of the piston Power tools.

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