JP4953023B2 - Sealing device for bearing - Google Patents

Description

  The present invention relates to a bearing sealing device.

JP 2003-194077 A JP 2005-282669 A

  Due to demands for smaller and lighter automobiles and further expansion of living space, the engine room space has been inevitably reduced, and electrical components and engine accessories have been further reduced in size and weight. Electromagnetic clutches and compressors for car air conditioners The idler pulley is no exception. However, a reduction in output is unavoidable due to downsizing, and an electromagnetic clutch compensates for the reduction in output by increasing the speed, and accordingly, the idler pulley is also increased in speed. Furthermore, since the engine room is being sealed due to a demand for improvement in quietness, and the high temperature in the engine room is promoted, these parts are also required to withstand high temperatures. In addition, since these parts are often attached to the lower part of the engine room, they are likely to be exposed to rain water, muddy water, etc. during traveling, and high sealing performance is required for the rolling bearings for these parts.

  Roller bearings for idler pulleys are used in such a manner that the inner ring is on the non-rotating side and the outer ring on which the pulley is fixed is on the rotating side. Such a rolling bearing sealing device includes a rubber main seal lip formed on the radially inner peripheral edge of the outer peripheral edge of the outer ring so as to be relatively non-rotatably fitted to the inner peripheral side of the axial end of the outer ring. However, it has a sliding seal part which slidably contacts the outer peripheral side of the axial end of the inner ring. In Patent Document 1, an inner ring side slinger (dust cover) fitted to a non-rotating inner ring is arranged oppositely on the outer side in the axial direction of such a sliding seal portion to suppress intrusion of dust or the like into the bearing. ing.

  In recent years, the conditions of use of automobiles have become more severe, and there are cases in which further increase in the amount of water is expected, such as when splashed muddy water or car wash water is jetted at a strong pressure, and flooding seen in RV cars, etc. Considering use in a submerged state or a submerged state, the bearing sealing device is required to have higher waterproofness. In Patent Document 2, a secondary seal lip (axial lip) that protrudes toward the inner ring-side slinger and contacts the inner surface of the slinger is formed on the outer surface in the axial direction of the sliding seal portion to further improve the sealing performance.

  However, in the configuration of Patent Document 2, the front end surface of the sub seal lip is formed flat and slanted outward in the radial direction, and is in sliding contact with the inner ring side slinger at the front end surface. When the secondary seal lip is elastically deformed by the centrifugal force, the tip end surface is likely to lift from the inner ring side slinger, and the sealing performance is likely to deteriorate even at a relatively low speed. In particular, when traveling while submerging in a river, even if the traveling speed is low, the sealing performance of the secondary seal lip is liable to be impaired, and the water that fills the surroundings can quickly penetrate into the bearing. Easy to connect.

  An object of the present invention is to provide a bearing sealing device that can achieve both high sealing performance of a bearing and low rotational torque during high-speed rotation.

Means for Solving the Problems and Effects of the Invention

The present invention is a bearing sealing device used for a radial bearing used in outer ring rotation, in order to solve the above problems,
An inner ring-side slinger that is arranged in such a manner as to block the annular opening of the rolling element arrangement space formed between the inner and outer rings in the axial direction, and the radially inner peripheral edge fits in the axial direction end of the inner ring in a relatively non-rotatable manner;
The inner ring side slinger is placed facing the inner ring in the axial direction to form an axial seal gap. The outer peripheral edge of the radial direction is fitted to the axial end of the outer ring in a relatively non-rotatable manner, and the inner ring is positioned on the inner peripheral side of the radial direction. A main seal lip made of an elastic polymer material that is in sliding contact with the outer end of the axial direction is formed, and the surface facing the inner ring side slinger is an axial base surface, and the tip portion extends from the axial base surface. A sliding seal portion formed with a secondary seal lip that is in sliding contact with the inner surface of the slinger in the axial direction;
The auxiliary seal lip that branches from the radially inner circumferential surface toward the inner surface of the inner ring side slinger has a predetermined amount of auxiliary seal clearance between the inner ring side slinger and the inner ring side slinger when the outer ring is not rotating. It is integrally formed with the extension length to be formed, and the auxiliary seal lip moves integrally with the auxiliary seal lip while reducing the auxiliary seal gap as the auxiliary seal lip collapses toward the axial base surface due to the increase in centrifugal force. Then, as the centrifugal force reaches a predetermined value, a sliding contact state with the inner ring side slinger inner surface is formed.

  According to the above configuration, since the secondary seal lip extends from the axial base surface of the sliding seal portion, the inner ring side is elastically deformed in such a way that it receives the centrifugal force accompanying the rotation of the outer ring and falls to the axial base surface side. The axial direction tightening margin by the inner ring side slinger at the lip tip which is in sliding contact with the inner surface in the axial direction of the slinger is reduced as the centrifugal force is reduced. As a result, the sliding resistance of the sub seal lip when the bearing rotates at a high speed can be reduced, and a reduction in rotational torque during high speed rotation can be achieved. For example, when driving while submerging in a river, the engine speed is not so high, so the centrifugal force acting on the outer ring of the bearing is low, and the secondary seal lip has a sufficient axial tightening allowance. It is possible to effectively prevent the problem that the water filling the surroundings penetrates into the bearing.

  On the other hand, when the centrifugal force becomes extremely large, the axial direction tightening margin of the secondary seal lip is significantly reduced, and the sealing effect by the secondary seal lip can no longer be expected. However, according to the present invention, the auxiliary seal lip that branches from the radially inner circumferential surface to the inner surface of the inner ring side slinger is provided between the inner surface of the inner ring side slinger when the outer ring is not rotating. It is integrally formed with an extension length that forms a predetermined amount of auxiliary seal gap. If the secondary seal lip falls greatly and deforms toward the axial base surface due to an increase in centrifugal force, the auxiliary seal lip moves integrally with the secondary seal lip while reducing the auxiliary seal gap, and a new sliding surface is formed between the inner ring side slinger inner surface. Since the contact state is formed, the sealing property can be maintained well even in such a case. As mentioned above, when running while submerging in a puddle on a rough road or in a river, if the wheels are stuck and floated in the water, the rotational speed of the wheels will rise rapidly, even though it is submerged. The margin for tightening the auxiliary seal lip in the axial direction is eliminated, and water can more easily penetrate into the bearing. However, in the present invention, since a new sliding contact state is formed by the auxiliary seal lip even in such a situation, leakage of water into the bearing can be effectively suppressed.

  If the axial force of the secondary seal lip by the inner ring side slinger increases to zero or negative (that is, there is a gap between the secondary seal lip and the inner ring side slinger) when the centrifugal force increases, Excluding the labyrinth sealing effect due to formation), the sealing effect by the secondary seal lip cannot be expected. Therefore, the size of the auxiliary seal gap is set so that the auxiliary seal lip moves from the non-sliding contact state to the sliding contact state with respect to the inner surface of the inner ring side slinger before the axial direction tightening margin of the sub seal lip becomes zero or negative. It can be said that it is desirable to define.

  The front end surface of the auxiliary seal lip can be flattened so as to face the inner surface of the inner ring side slinger in parallel. If the auxiliary seal lip is flattened and the auxiliary seal gap is formed in parallel with the inner surface of the inner ring side slinger, the movement direction of the auxiliary seal lip's tip surface with deformation of the sub seal lip is Even if it is inclined with respect to the inner normal direction of the inner ring side slinger, the auxiliary seal lip can be slidably contacted with the inner surface of the inner ring side slinger somewhere on the flat tip surface to ensure the sealing performance at high speed rotation. it can.

  It is desirable that the auxiliary seal lip be formed so as to branch obliquely inward in the radial direction from the radial inner peripheral surface of the sub seal lip. More specifically, in the cross section including the bearing rotation axis, the intersection of the radial inner circumferential surface and the axial base surface of the sub seal lip is S, and the perpendicular foot that is lowered from the intersection S toward the inner surface of the inner ring side slinger. And T, and the radial inner peripheral edge position of the tip end surface of the auxiliary seal lip from the intersection S is SE> ST, and the line segment SE is inclined with respect to the line segment ST in an acute angle inward in the radial direction. It is desirable to determine the cross-sectional shape of the auxiliary seal lip so that Thus, when the sub seal lip is greatly tilted and deformed by the centrifugal force, the auxiliary seal lip can be reliably brought into sliding contact with the inner surface of the inner ring side slinger.

  Next, the secondary seal lip has a sliding contact edge formed at the tip of the lip, and in a virtually undeformed state in which the inner ring side slinger is omitted, the sliding contact edge is a fixed distance in the axial direction from the inner surface position of the inner ring side slinger. It is located on the outside, and the tip of the lip against the inner surface of the inner ring side slinger forms an annular belt-like slidable contact surface on the radially inner circumferential surface with the slidable contact edge as the contact start side. However, the radial width of the annular belt-shaped sliding contact surface formed between the lip tip and the inner ring side slinger is reduced toward the sliding contact edge as the centrifugal force increases. Can be configured.

  According to the above configuration, the secondary seal lip that is in sliding contact with the inner ring side slinger has a sliding contact edge at the lip tip. When the inner ring side slinger is omitted and is virtually undeformed, the sliding contact edge is positioned outside by a certain distance in the axial direction from the inner surface position of the inner ring side slinger. When considered in the non-deformed state, the axial extension amount of the sliding contact edge from the inner ring side slinger inner surface corresponds to the axial tightening allowance of the sub seal lip. By forming such an allowance, the lip tip of the secondary seal lip is in the radial direction with the sliding contact edge (not the tip) as the contact start side with respect to the inner surface of the inner ring side slinger. Abutting in an elastic bending deformation while forming an annular belt-like sliding contact surface on the inner peripheral surface.

  In this state, when the centrifugal force accompanying the rotation of the outer ring acts, the secondary seal lip elastically deforms outward in the radial direction, that is, tilts toward the axial base surface side, and the amount of tilt increases as the acting centrifugal force increases. Increase. Considering the above-mentioned non-deformation state, the axial extension amount (tightening margin) from the inner ring side slinger inner surface of the sliding contact edge decreases as the acting centrifugal force increases. Along with this, the radial inner circumferential surface of the lip tip part is turned up in the radial direction from the opposite side while maintaining the contact position of the sliding contact edge substantially constant, and is formed in an annular band shape formed on the inner ring side slinger. As the centrifugal force increases, the radial width of the sliding contact surface decreases toward the sliding contact edge.

  As a result, the sealability of the bearing and the self-adjusting function of the rotational torque according to the rotational speed can be further enhanced. That is, the sliding contact surface of the secondary seal lip is formed in an annular belt shape, and as the rotational speed of the bearing increases, the width of the sliding contact surface decreases in the radial direction due to the centrifugal force, so sliding friction can be effectively reduced. It is possible to prevent an increase in bearing torque during high-speed rotation. Further, the secondary seal lip of this form can maintain the sliding contact state only by reducing the width of the sliding contact surface even if the centrifugal force is increased to some extent, and the secondary seal lip is less likely to be lifted from the inner ring side slinger. In addition, the ring-shaped sliding contact surface is formed while elastically bending and deforming in such a way that it does not hit the surface in the normal direction of the slinger inner surface from the tip side but hits the line from the sliding contact edge. Even if the width of the surface is somewhat reduced, the sealing performance is not easily lost.

  For the secondary seal lip, the lip length defined as the dimension from the starting point of the axial base surface to the sliding contact edge in the generatrix direction of the inner circumferential surface in the radial direction is defined as the radial dimension of the crossing surface with the axial base surface It is desirable that the thickness is adjusted to be larger than the lip base end thickness. As a result, when centrifugal force is applied, the elastic deformation of the collapsed form of the secondary seal lip toward the axial base surface can proceed smoothly, and the sealing performance and the self-adjusting function of the rotational torque according to the bearing rotational speed Can be made more obvious.

  In addition, when a situation occurs in which the rolling element arrangement space becomes negative pressure, the suction force is more likely to enter the bearing such as water droplets, but when the configuration of the present invention is adopted, the negative pressure suction force As a result, the secondary seal lip is elastically deformed inward in the radial direction. As a result, the radial width of the ring-shaped sliding contact surface formed between the lip tip and the inner ring side slinger can be increased as the negative pressure increases, greatly improving the sealing performance when negative pressure occurs. be able to.

  The front end surface of the sub seal lip can be a flat surface. As a result, the secondary seal lip can sharpen the sliding contact edge formed at the intersection of the radially inner circumferential surface and the tip surface while maintaining an appropriate rigidity, and can enhance the effect of improving the sealing performance by line contact. it can.

  The lip tip of the sub-seal lip can be shaped to taper at an acute angle in the cross section including the bearing rotation axis. By making the tip of the lip taper like this, the tip of the sub-seal lip can bend well and the adhesion to the inner ring side slinger can be improved.

  Further, the entire sub seal lip can be formed in a wedge shape that continuously reduces the lip thickness from the rising base end side to the sliding contact side tip in the cross section including the bearing rotation axis. . As a result, the lip thickness at the base end of the secondary seal lip can be secured above a certain level, the secondary seal lip can be prevented from reversing in the radial direction during assembly, and the tip of the lip is tapered. The above effects can be achieved at the same time. In this case, the sub-seal lip may have a shape that is curved in advance so that the whole or the lip tip bulges toward the radially inner circumferential surface that is in contact with the inner ring side slinger. However, from the viewpoint of ensuring a large seal tightening margin, in the cross section including the bearing rotation axis, the acute angle crossing angle between the outer peripheral line indicating the radial inner peripheral surface and the axial base surface is the same as the outer line indicating the outer peripheral surface. It is desirable that all of the outlines in the non-deformed state are linear so as to be smaller than the acute angle crossing angle with the axial base surface.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a bearing to which a bearing sealing device of the present invention is applied. The bearing 1 is for rotating and supporting an automobile idler pulley, and is configured as a double row deep groove ball bearing (radial bearing) used so that the inner ring 3 is non-rotating and the outer ring 4 is rotating. Yes. The balls 5 and 5 forming the rolling elements are arranged in the rolling element arrangement space 15 formed between the inner ring 3 and the outer ring 4 while the circumferential arrangement interval is regulated by the cages 6 and 6 in each row. Yes. A pulley 20 is concentrically fitted on the outer peripheral surface of the outer ring 4.

  The bearing 1 is provided with bearing sealing devices 7 and 7 in annular openings 15 a and 15 a that respectively appear at both ends in the axial direction of the rolling element arrangement space 15. The bearing sealing devices 7 and 7 on either side have exactly the same configuration, and the main parts thereof include an inner ring side slinger 10 and a sliding seal portion 8.

  FIG. 2 is an enlarged cross-sectional view showing details of one of the bearing sealing devices 7, and the inner ring side slinger 10 has an annular opening 15 a in the rolling element arrangement space 15 formed between the inner and outer rings 3 and 4. Is arranged in such a manner that the inner peripheral edge portion in the radial direction is fitted to the end portion in the axial direction of the inner ring 3 so as not to be relatively rotatable. Specifically, the inner ring side slinger 10 has an annular main body plate 10m disposed concentrically with the inner ring 3 so that the plate thickness direction coincides with the axial direction, and the inner ring side slinger 10 extends in the axial direction from the inner periphery of the opening of the main body plate 10m. And a cylindrical portion 10f integrally formed so as to protrude in the direction. A midway section portion in the radial direction of the main body plate 10m bulges inward in the axial direction from both end section portions, and is an annular reinforcing bulge portion 10d having a flat inner surface 10a. An annular inner ring side step 42 is formed on the outer peripheral edge of the axial end surface of the inner ring 3. The cylindrical portion 10f of the inner ring side slinger 10 is press-fitted to the inner peripheral surface 42a of the inner ring side stepped portion 42.

  Next, the sliding seal portion 8 is disposed opposite to the inner ring side slinger 10 so as to form an axial seal gap 17 on the inner side in the axial direction. The outer peripheral edge in the radial direction is fitted to the axial direction end of the outer ring 4 so as not to be relatively rotatable, and the main seal lip 9 made of an elastic polymer material slidably in contact with the outer side of the axial end of the inner ring 3 on the inner peripheral edge side in the radial direction. Is formed. Further, a surface opposite to the inner ring side slinger 10 is used as an axial base surface 8b, and a secondary seal lip made of an elastic polymer material so as to rise obliquely outward in the radial direction while traversing the axial seal gap 17 from the axial base surface 8b. 94 is formed, and the tip of the sub seal lip 94 is in sliding contact with the inner surface 10a in the axial direction of the inner ring side slinger 10 (which forms the inner surface of the reinforcing bulging portion 10d described above).

  Specifically, the sliding seal portion 8 includes a seal core 81 arranged so that the plate thickness direction coincides with the axial direction, and an elastic polymer material covering a plate surface outside the axial direction of the seal core 81 And a seal main body 8M. The main seal lip 9 is integrally formed with the seal body 8M so as to extend inward in the radial direction from the radial inner peripheral edge of the seal core 81. The sub seal lip 94 is integrally formed with the seal body 8M in such a manner that the outer surface in the axial direction of the seal body 8M is an axial base surface 8b.

  The seal core 81 is integrally formed with an annular main body plate 81m arranged so that the plate thickness direction coincides with the axial direction, and protruding inward in the axial direction from the outer peripheral edge of the main body plate 81m. It has a cylindrical wall portion 81a and a flange portion 81b extending radially outward from the axial end edge of the cylindrical wall portion 81a. The outer peripheral edge portion of the seal body 8M forms an annular fitting lip 8e having a rectangular cross section so as to surround the cylindrical wall portion 81a and the flange portion 81b. On the other hand, a reinforcing bent portion 81c is formed on the inner peripheral side of the seal core 81 so as to be bent obliquely inward in the axial direction. The seal body 8M wraps around the reinforcing bent portion 81c in the radial direction. A main seal lip 9 is formed extending inward.

  The inner peripheral edge portion of the end surface in the axial direction of the outer ring 4 is notched in a stepped shape in the circumferential direction, and an annular outer ring side notch portion 41 is formed. The fitting lip 8e is press-fitted and fitted so as to be in close contact with the bottom surface 41a and the inner peripheral surface 41b of the outer ring side cutout 41. In addition, a retaining rib 41r is formed to protrude in the circumferential direction at an end portion in the axial direction on the open side of the inner peripheral surface 41b of the outer ring side cutout portion 41, and the fitting lip 8e elastically moves the retaining rib 41r. It gets over and is fitted in the outer ring side cutout 41.

  The main seal lip 9 has a base 91 extending radially outward from the seal body 8M and an inner lip 92 extending axially inward from the base 91. The inner lip 92 extends from the base 91 on the radially inner side toward the bottom surface 42b of the inner ring side stepped portion 42 and slidably contacts the bottom surface 42b, and the base 91 on the radially outer side of the inner slidable lip 92a. The inner auxiliary lip 92b extends from the base 91 on the radially outer side of the inner auxiliary lip 92b to the inner side in the axial direction. The outer lip 93 has a first outer lip 93a extending outward in the axial direction at substantially the same position as the radial direction of the inner sliding lip 92a in the base 91, and a radial position of the inner auxiliary lip 92b in the base 91. A second outer lip 93b extending outward in the axial direction.

  At the beginning of use, the inner lip 92 is configured such that only the inner sliding lip 92a is in sliding contact with the bottom surface 42b of the inner ring side step portion 42, and the inner auxiliary lip 92b is not in sliding contact with the bottom surface 42b of the inner ring side step portion 42. Yes. The inner auxiliary lip 92b comes into slidable contact with the bottom surface 42b of the inner ring side stepped portion 42 when the inner slidable contact lip 92a wears a certain amount after the service of the bearing 1 is started. The axial lip 92 c forms a labyrinth seal with the outer peripheral surface 3 a of the inner ring 3. In order to perform sliding lubrication of each seal lip, grease is attached to the bottom surface 42b of the inner ring side stepped portion 42 and the inner surface 10a of the inner ring side slinger 10.

  Next, FIG. 3 is an enlarged cross-sectional view of the sub seal lip 94, and FIG. 6 is an enlarged cross-sectional view of the sliding contact side tip portion 94t. The sub seal lip 94 has a slidable contact edge 94e formed at the intersection of the tip surface 94c of the lip tip portion 94t and the radially inner circumferential surface 94a. The upper part of FIG. 3 shows the sub seal lip 94 in a virtual undeformed state in which the inner ring side slinger 10 is omitted. In the actual assembled state of the bearing, the secondary seal lip 94 is always elastically deformed by the inner ring side slinger 10 when the bearing is not rotating. However, if the internal ring side slinger 10 is removed, the secondary seal lip 94 is not removed. The shape in the deformed state can be confirmed. The sliding contact edge 94e is located outside by a certain distance in the axial direction from the position of the inner surface 10a of the inner ring side slinger 10 in the non-deformed state (and the bearing non-rotating state). The axial extension amount of the sliding contact edge 94e from the inner ring-side slinger 10 inner surface when considered in the non-deformed state gives an axial direction tightening allowance δ of the sub seal lip 94.

  If the inner ring side slinger 10 is actually arranged by being in a non-deformed state as shown in FIG. 3, as shown in the lower part of FIG. 3, the secondary seal lip 94 has a lip tip 94t with respect to its inner surface 10a. Thus, the sliding contact edge 94e is brought into contact with the contact start side, and an annular belt-shaped sliding contact surface 94a ′ is formed on the radial inner circumferential surface 94a so as to be elastically bent and deformed. The tip surface 94c is not in contact with the inner ring side slinger 10.

  In this state, when a centrifugal force accompanying the rotation of the outer ring 4 acts, as shown in FIG. 4, the sub seal lip 94 is elastically deformed so as to fall outward in the radial direction, that is, to fall to the axial base surface 8b side. The amount of tilting increases as the acting centrifugal force increases. Considering the non-deformed state shown in FIG. 3, the axial direction tightening allowance δ becomes smaller as the amount of tilt increases. Then, as shown by a broken line in FIG. 4, the radial inner peripheral surface 94a of the lip tip 94t is turned up in the radial direction from the opposite side while maintaining the contact position of the sliding contact edge 94e substantially constant, The annular band-shaped sliding contact surface 94a ′ formed on the inner ring side slinger 10 has a radial width W that decreases toward the sliding contact edge 94e as the centrifugal force increases. That is, when the radial width of the sliding contact surface 94a ′ when the outer ring 4 is not rotating is W0, and the radial width when the outer ring 4 is rotated and centrifugal force is applied is W1, W1 <W0. Become.

  Thereby, the sub seal lip 94 embodies the function of self-adjusting the sealing performance and the rotational torque of the bearing according to the rotational speed of the outer ring 4. That is, the sliding contact surface 94a ′ of the secondary seal lip 94 is formed in an annular belt shape, and the width of the sliding contact surface 94a ′ is reduced in the radial direction by the centrifugal force as the rotational speed of the outer ring 4 increases. Can be effectively reduced, and an increase in bearing torque during high-speed rotation can be prevented.

  Even if the centrifugal force is increased to some extent, the secondary seal lip 94 can maintain the sliding contact state only by reducing the width of the sliding contact surface 94 a ′, and the secondary seal lip 94 is less likely to be lifted from the inner ring side slinger 10. And, as shown in FIG. 6, it is not a surface contact from the front end side in the normal direction of the slinger inner surface, but a line contact from the sliding contact edge 94 e at the boundary between the front end surface 94 c and the radial inner peripheral surface 94 a. Therefore, as shown in the lower part of FIG. 3, the ring-shaped sliding contact surface 94a ′ is formed while being elastically bent and deformed. Therefore, even if the width of the sliding contact surface 94a ′ is somewhat reduced by centrifugal force, the sealing performance is not easily impaired. For example, when traveling while submerging in a river, the width of the sliding contact surface 94a ′ becomes sufficiently large as the centrifugal force decreases, so that the sealing performance of the secondary seal lip 94 can be enhanced. Can be effectively prevented from penetrating into the bearing.

  As shown in the upper part of FIG. 3, when the sub seal lip 94 is subjected to centrifugal force in the above-described non-deformed state, the sub seal lip 94 smoothly deforms elastically in a collapsed state toward the axial base surface 8 b side. In order to advance, the lip length L defined as the dimension from the rising starting position from the axial base surface 8b to the sliding contact edge 94e in the generatrix direction of the radially inner peripheral surface 94a is the radial of the plane intersecting the axial base surface 8b. It is adjusted to be larger than the lip base end thickness θ defined as the directional dimension.

  Further, the front end surface 94c of the sub seal lip 94 is a flat surface as shown in the left of FIG. As a result, the sub seal lip 94 can sharpen the sliding contact edge 94e formed at the crossing position between the radially inner circumferential surface 94a and the tip end surface 94c while maintaining an appropriate rigidity, and the effect of improving the sealing performance due to line contact. Can be increased. As shown on the right side of FIG. 6, the front end surface 94c of the sub seal lip 94 may be a stepped shape. Specifically, the stepped shape is achieved by forming the projection 94f on the opposite side of the tip 94c where the sliding contact edge 94e is formed. Further, as shown in FIG. 7, it is also possible to use a tip surface 94c ′ having a convex curved surface shape, or a tip surface 94c ″ having a concave curved surface shape as shown in FIG. In the case where the rotating body is in the shape of the axis and the tip surface 94c ′ has a convex curved surface as shown in FIG. 7, the sliding contact edge 94e is defined as follows: That is, as shown in FIG. Thus, when considered in the cross section including the bearing rotation axis in the non-deformed state, the tangent line 10c ′ circumscribing in parallel with the inner surface of the inner ring side slinger 10 with respect to the outer line of the lip tip portion 94t including the tip surface 94c. (It becomes a cylindrical surface spatially.) At this time, it is considered that a contact point (spatially a circle) between the tangent line 10c ′ and the outer shape line forms the sliding contact edge 94e. As shown in FIG. When chamfering is given to the sliding contact edge position, the lip tip portion is slidably contacted with the belt-like surface 94j having a certain width in the chamfering section. In this case, the lip tip portion is radially inward of the belt-like surface 94j. The positioned edge is regarded as the sliding contact edge 94e.

  Returning to FIG. 3, the lip front end portion 94 t of the sub seal lip 94 has an acute angle tapered shape in a cross section including the bearing rotation axis. By making the lip tip portion 94t have such a tapered shape, the tip end of the sub seal lip 94 becomes good and the adhesion to the inner ring side slinger 10 can be improved. In the configuration of FIG. 3, the entire secondary seal lip 94 has a wedge that continuously reduces the lip thickness from the rising base end side from the axial base surface 8 b toward the sliding contact side tip in a cross section including the bearing rotation axis. It is made into a shape. Since the lip thickness at the base end portion of the sub seal lip 94 is increased, the problem that the sub seal lip 94 is reversed in the radial direction at the time of assembly or the like can be prevented, and the lip tip side is tapered. The effect of can be achieved at the same time.

  Further, as shown in the upper part of FIG. 3, the sub seal lip 94 has the same acute angle crossing angle φ1 between the outer peripheral line showing the radial inner peripheral surface 94a and the axial base surface 8b in the cross section including the bearing rotation axis. The outer shape in the non-deformed state is all linear so as to be smaller than the acute angle crossing angle φ2 between the outer shape line indicating the outer peripheral surface and the axial base surface 8b. However, in order to adjust the tightening margin of the lip tip, the entire sub-seal lip 94 or the lip tip 94t is arranged on the radial inner peripheral surface 94a side, which is a contact side with the inner ring side slinger 10, as shown in FIG. It is also possible to have a shape bent in advance, or as shown in FIG. 10, a shape that is curved in advance so as to bulge toward the radially inner circumferential surface 94a.

  Next, as shown in FIG. 3, the auxiliary seal lip 94 has an annular auxiliary seal lip 95 that branches from the radially inner circumferential surface toward the inner surface of the inner ring side slinger 10, while the outer ring 4 is not rotated. The inner ring side slinger 10 is integrally formed with an extended length that forms a predetermined amount of auxiliary seal gap β between the inner ring side slinger 10 and the inner ring side slinger 10. As shown in FIG. 4, the auxiliary seal lip 95 is integrated with the auxiliary seal lip 94 while reducing the auxiliary seal gap β as the auxiliary seal lip 94 falls and deforms toward the axial base surface 8b due to an increase in centrifugal force. Moving. As the centrifugal force reaches a predetermined value, as shown in FIG. 5, the auxiliary seal lip 95 erodes the auxiliary seal gap β and newly forms a sliding contact state with the inner surface of the inner ring side slinger 10.

That is, when the centrifugal force becomes extremely large, the axial direction tightening margin of the sub seal lip 94 is significantly reduced, and the lip tip 94t is lifted from the inner ring side slinger 10 as shown in FIG. (That is, a state where the axial direction interference is a negative value). In this state, except for the labyrinth seal effect due to a slight gap width ε,
The sealing effect by the secondary seal lip 94 can no longer be expected. However, since the auxiliary seal lip 95 as described above is formed on the sub seal lip 94, a new sliding contact state is formed between the inner ring side slinger 10 and the inner surface, so that the sealing performance can be maintained well. it can. For example, when driving while submerging in a puddle on a rough road or in a river, if the wheel stacks and floats in the water, the rotation speed of the wheel temporarily increases rapidly, and the sub seal lip is in spite of being submerged. The allowance of 94 in the axial direction is eliminated, and water becomes more easily penetrated into the bearing. However, by forming a new slidable contact state with the auxiliary seal lip 95, water leakage to the bearing can be effectively suppressed.

  The size of the auxiliary seal gap β is such that the auxiliary seal lip 95 is first tightened in the axial direction when the auxiliary seal lip 95 moves from the non-sliding contact state to the sliding contact state with respect to the inner surface of the inner ring side slinger 10. It can be determined to be zero or a negative value. In this case, when the centrifugal force increases to a predetermined value, there occurs a period in which both the auxiliary seal lip 94 and the auxiliary seal lip 95 are in a non-sliding state. Therefore, the high-speed rotation state of the bearing corresponding to the centrifugal force In, the bearing rotational torque can be greatly reduced. However, it is also possible to determine the size of the auxiliary seal gap β so that when the auxiliary seal lip 95 shifts from the non-sliding contact state to the slidable contact state, a certain amount of axial tightening margin of the sub seal lip 94 remains. is there.

  In FIG. 3, the front end surface 95 c of the auxiliary seal lip 95 is flattened so as to face the inner surface of the inner ring side slinger 10 in parallel. If the auxiliary seal lip 95 is flattened so that the auxiliary seal gap β is formed so as to face the inner surface of the inner ring side slinger 10 in parallel, the front end of the auxiliary seal lip 95 accompanying the deformation of the sub seal lip 94 is formed. Even if the moving direction of the surface 95c is inclined with respect to the normal direction of the inner surface of the inner ring side slinger 10, the auxiliary seal lip 95 can be slidably contacted with the inner surface of the inner ring side slinger 10 somewhere on the flat tip surface. Sealing performance during rotation can be ensured.

  Next, the auxiliary seal lip 95 is formed so as to branch obliquely inward in the radial direction from the radially inner circumferential surface of the sub seal lip 94. More specifically, as shown in FIG. 4, in the cross section including the bearing rotation axis, the intersection of the radial inner peripheral surface 94a and the axial base surface 8b of the sub seal lip 94 is S, and the inner ring side slinger is formed from the intersection S. 10 is SE> ST and the line segment SE with respect to the line segment ST, where T is the foot of the perpendicular line that is directed toward the inner surface of 10 and E is the radial inner peripheral position of the tip surface 95c of the auxiliary seal lip 95 from the intersection S. The cross-sectional shape of the auxiliary seal lip 95 is determined so as to incline with an acute angle inward in the radial direction. When the radial inner peripheral surface 94a is considered to rotate approximately around the intersection S (that is, the base end point extending from the axial base surface 8b) as the sub seal lip 94 falls down, The radial inner peripheral edge position E of the surface 95c moves along a rotation locus having a radius R as the line segment SE. Since SE> ST, the radially inner peripheral edge position E of the front end surface 95c is rotated by a certain angle so as to come into contact with the inner surface 10c of the inner ring side slinger 10. Thereafter, as the sub seal lip 94 further falls and deforms, the front end surface 95c of the auxiliary seal lip 95 expands the sliding contact area with the inner surface 10c of the inner ring side slinger 10 from the inner peripheral edge position E side outward in the radial direction. Will be.

  In addition, the outer surface in the axial direction of the inner ring side slinger 10 may be coated with at least a seal layer 98 formed of rubber or the like in the radial inner peripheral edge portion to be fitted to the inner ring 3 as shown by a one-dot chain line in FIG. it can. Thereby, it can suppress effectively that water etc. osmose | permeate the fitting surface of the inner ring | wheel side slinger 10 and the inner ring | wheel 3. In the present embodiment, the seal layer 98 covers the entire outer surface in the axial direction of the inner ring side slinger 10 so as to wrap around the inner surface in the axial direction on the outer peripheral edge side in the radial direction.

Sectional drawing which shows an example of the bearing for idler pulleys which applied the sealing device for bearings of this invention. Sectional drawing which expands and shows the sealing device part for bearings of FIG. Sectional drawing which expands and shows the sub seal lip of the sealing device for bearings of FIG. 2 in both a non-deformation state and a mounting state. Action | operation explanatory drawing of a sub seal lip. Explanatory drawing of an effect | action of a sub seal lip when a centrifugal force further increases. The expanded sectional view which shows the 1st example of the lip tip shape of a sub seal lip. The expanded sectional view which shows a 2nd example similarly. The expanded sectional view which shows a 3rd example similarly. The front-end | tip expanded sectional view which shows the modification which carries out bending formation of the sub seal lip previously. The front-end | tip expanded sectional view which shows the modification which carries out curve formation of the sub seal lip previously.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bearing 3 Inner ring 4 Outer ring 7 Bearing sealing device 8 Sliding seal part 8b Axial base surface 9 Main seal lip 94 Sub seal lip 94a Radial direction inner peripheral surface 94a 'Sliding contact surface 94e Sliding contact point 94t Lip tip portion 95 Auxiliary seal Lip 10 Inner ring side slinger 15 Rolling element arrangement space 15a Annular opening 17 Axial seal gap β Auxiliary seal gap

Claims (4)

A radial bearing sealing device used in outer ring rotation,
An inner ring side slinger that is arranged in such a manner as to block the annular opening of the rolling element arrangement space formed between the inner and outer rings in the axial direction, and the radial inner peripheral edge is fitted to the axial end of the inner ring in a relatively non-rotatable manner. When,
The inner ring side slinger is opposed to the inner ring side so as to form an axial seal gap, and the outer peripheral edge portion in the radial direction is fitted in the axial direction end portion of the outer ring so as not to rotate relative to the inner ring side. A main seal lip made of an elastic polymer material that is slidably in contact with the outer end of the inner ring in the axial direction is formed. A sliding seal portion formed with a sub seal lip that is in sliding contact with the inner surface in the axial direction of the inner ring side slinger,
The sub seal lip has an auxiliary seal lip branched from the radially inner circumferential surface toward the inner surface of the inner ring side slinger, and a predetermined amount between the inner ring side slinger and the inner ring side slinger when the outer ring is not rotating. The auxiliary seal lip is formed integrally with an extension length that forms an auxiliary seal gap, and as the centrifugal force increases, the auxiliary seal lip collapses toward the axial base surface and deforms. A bearing sealing device, wherein the bearing sealing device moves integrally with the sub seal lip while being reduced, and forms a sliding contact state with the inner ring side slinger inner surface as the centrifugal force reaches a predetermined value.   At least until the auxiliary seal lip is in non-sliding contact with the inner surface of the inner ring side slinger until the centrifugal force increases and the axial direction tightening margin of the sub seal lip by the inner ring side slinger becomes zero or negative. The bearing sealing device according to claim 1, wherein a size of the auxiliary seal gap is determined so as to shift to the sliding contact state.   The bearing sealing device according to claim 1 or 2, wherein a front end surface of the auxiliary seal lip is flattened so as to face the inner surface of the inner ring side slinger.   The secondary seal lip has a sliding contact edge formed at the tip of the lip, and in a virtually undeformed state in which the inner ring side slinger is omitted, the sliding contact edge is a fixed distance in the axial direction from the inner surface position of the inner ring side slinger. An annular belt-like slidable contact is formed on the radially inner circumferential surface so that the lip tip is on the contact start side with respect to the inner surface of the inner ring side slinger. A radial contact width of the ring-shaped sliding contact surface formed between the inner lip side slinger and the lip tip is formed by elastic bending deformation while forming a surface, as the centrifugal force increases. The bearing sealing device according to any one of claims 1 to 3, wherein the bearing sealing device is reduced toward the sliding contact edge.

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