JP2006162019A - Thrust bearing for strut, and thrust bearing device for strut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thrust bearing for a strut and a thrust bearing device for the strut capable of properly supporting a coil spring by inhibiting the deformation of a bearing ring and a cover member without increasing a weight. <P>SOLUTION: In the thrust bearing device 10 for the strut, an annular second bearing ring 12 has a reinforcing rib portion 12d formed by bending its inner peripheral-side end portion 12c toward an axial lower portion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a strut thrust bearing and a strut thrust bearing device used in a strut suspension of a vehicle such as an automobile.

Conventionally, strut type suspensions are frequently used as suspensions used for steering wheels of vehicles such as automobiles. This strut suspension has a columnar strut provided with a coil spring that absorbs an impact from a wheel.
As described in, for example, Patent Document 1, the strut has, at its upper end, a strut upper plate (upper mount) fixed to the vehicle side and the coil spring disposed below the strut upper plate. A metal spring upper cover that is in contact with the upper end of the coil and receives the load from the coil spring is attached. A thrust bearing is mounted between the strut upper plate and the spring upper cover. The thrust bearing includes an annular first raceway that is press-formed from a steel plate, and an annular second raceway that is disposed opposite to the lower side in the axial direction of the first raceway and is press-formed from a steel plate. A ring, a plurality of rolling elements that are arranged to be freely rollable between the two race rings, and an upper cover and a lower cover that respectively cover the race rings, and the spring upper cover and the coil spring are connected to the strut upper. The wheel can be steered by supporting the plate (vehicle) so as to be swingable.

In recent years, automobiles and the like have been required to be lighter as a whole vehicle from the viewpoint of energy saving such as improvement in fuel efficiency, and a further reduction in weight has been required for a suspension mounted thereon.
Therefore, for the purpose of reducing the weight of the strut suspension, a seat surface is formed on the lower cover attached to the lower surface of the second bearing ring of the thrust bearing so that the upper end of the coil spring contacts and receives the coil spring. Therefore, a strut using a strut thrust bearing device in which the spring upper cover and the thrust bearing are integrally formed has been devised.
Such a thrust bearing device for struts can be configured such that the spring upper cover is eliminated, so that the number of strut parts is reduced, and the strut suspension is reduced in weight and size.

JP 2001-132761 A (page 5)

However, the thrust bearing described in Patent Document 1 is pressed against the vehicle side by the load from the coil spring, and an excessive axial load acts on the thrust bearing depending on the traveling state of the vehicle. In some cases, the two bearing rings are deformed by this load.
Further, in the thrust bearing device for struts in which the spring upper cover and the thrust bearing are integrally configured, the upper end surface of the coil spring does not contact the seat surface uniformly in the circumferential direction. The thrust bearing device for struts is subjected to a nonuniform uneven load in the circumferential direction by the coil spring. Due to this uneven load, in the thrust bearing device for struts, the deformation in the thrust direction occurs unevenly in the circumferential direction, and the same deformation may occur in both race rings. In particular, when the cover member is made of resin, the cover member itself is low in rigidity, so that it is easily deformed, and the deformation of the cover member induces deformation of the second race ring. There was a case.

As described above, when deformation occurs in both the races, the thrust bearing device for struts has a coil spring that prevents the smooth movement between the races and the rolling elements and increases the rotational torque. There was a risk that the vehicle could not be supported properly.
On the other hand, it is conceivable to increase the thickness of both the bearing rings and the cover member to increase the rigidity. However, in this case, the weight increases and the thickness of the thrust bearing device itself increases. Advantages such as weight reduction by mounting the thrust bearing device on the vehicle are impaired.

  The present invention has been made in view of such circumstances, and a thrust bearing for struts that can appropriately support a coil spring by suppressing deformation of the race and the cover member with almost no increase in weight. And it aims at providing the thrust bearing apparatus for struts.

  The present invention includes an annular first race ring, an annular second race ring disposed opposite to the first race ring in the axial direction, and a rollable arrangement between the two race rings. In the strut thrust bearing provided with the plurality of rolling elements, at least one of the race rings is formed by bending at least one of the inner circumferential side and the outer circumferential side end portions. It has the featured reinforcing rib portion.

  According to the strut thrust bearing configured as described above, the bearing ring has the reinforcing rib portion formed by bending the end portion thereof, so that the bearing ring does not cause a significant increase in weight. The rigidity of can be increased.

  Further, the present invention provides a ring-shaped first race ring, an annular second race ring arranged opposite to the first race ring in the axial direction, and freely rollable between the both race rings. A thrust bearing device for struts, comprising: a plurality of rolling elements disposed on the bearing ring; and a cover member that is formed of a material having lower rigidity than the raceway ring and covers the raceway ring. At least one of the race rings has a reinforcing rib portion formed by bending at least one of the inner peripheral side and the outer peripheral end.

According to the thrust bearing device for struts configured as described above, the raceway has the reinforcing rib portion formed by bending the end portion thereof, so that the raceway does not cause a large increase in weight. The rigidity of the ring can be increased.
Furthermore, the bearing ring whose rigidity is increased by the reinforcing rib portion acts as a reinforcing member that reinforces the cover member covering the bearing ring, and as a result, the rigidity of the cover member can be increased.

  In the strut thrust bearing device, the cover member is preferably configured to receive a load of a coil spring that absorbs an impact from a wheel. In this case, as described above, the rigidity of the raceway ring and the cover member can be increased, and therefore, even if a biased load from the coil spring is received, deformation of the raceway ring and the cover member in the thrust direction is suppressed. And the coil spring can be properly supported.

  In the thrust bearing device for a strut, it is preferable that the reinforcing rib portion is bent substantially in the axial direction. In this case, since the reinforcing rib portion is formed substantially parallel to the direction of the load acting on the strut thrust bearing device, the rigidity of the raceway can be further increased.

  In the thrust bearing device for a strut, it is preferable that the reinforcing rib portion is provided so as to contact the cover member. In this case, the bearing ring having the reinforcing rib portion can increase the contact area with the cover member. Therefore, the effect | action as a reinforcement member which reinforces the said cover member is heightened, and the rigidity of the said cover member can be improved more.

  As described above, according to the strut bearing and the strut thrust bearing device of the present invention, the rigidity of the bearing ring and the cover member can be increased without incurring a large weight increase. However, these deformations can be suppressed and the coil spring can be supported appropriately.

  Next, an embodiment of a thrust bearing device for a strut according to the present invention will be described with reference to the accompanying drawings. In the following description, a case where the present invention is applied to a strut of a strut suspension of a steering wheel of an automobile will be described as an example.

FIG. 1 is a partial cross-sectional view of an upper end portion of a strut using a strut thrust bearing device according to an embodiment of the present invention. In FIG. 1, a strut 51 is a columnar suspension constituent member provided with a coil spring 53 that absorbs an impact from a wheel, and an upper mount 52 fixed to the vehicle side at an upper end portion thereof, and the upper mount 52. A strut thrust bearing device 10 that contacts the lower surface of the coil spring 53 and contacts the upper end of the coil spring 53 to receive a load from the coil spring 53.
FIG. 2 is an enlarged cross-sectional view of the strut thrust bearing device 10 in FIG.
The strut thrust bearing device 10 is disposed between an upper mount 52 and a coil spring 53 that absorbs an impact from a wheel, and includes an annular first race ring 11 and the first race ring 11. The second ring ring 12 having an annular shape opposed to the lower side in the axial direction, a plurality of balls 13 as rolling elements arranged so as to roll freely between them, and the upper surface of the first ring 11 The first cover member 14 made of an annular resin that is integrally attached so as to cover the upper surface, and the second cover member 15 made of an annular resin that is integrally attached so as to cover the lower surface of the second race 12. And have.

The first track ring 11 is press-formed from a steel plate, and a track 11a on which the balls 13 roll is formed on the lower surface side. The first bearing ring 11 includes a first reinforcing rib portion 11c formed by bending the outer peripheral end portion 11b and a second reinforcing rib formed by bending the inner peripheral end portion 11d. Part 11e. Both the reinforcing rib portions 11c and 11e are formed by bending the inner peripheral side and the outer peripheral end of the first race ring 11, and for example, by a bent portion 11f bent to form the track 11a. The portion to be formed is not included in the reinforcing rib portion.
The first cover member 14 that covers the upper surface of the first track ring 11 is formed using a resin having a rigidity lower than that of the steel plate, and the first cover member 14 extends along the upper surface of the first track ring 11. One track ring 11 is attached integrally. The upper surface of the first cover member 14 is formed to be substantially flat and is in contact with the lower surface 52 a of the upper mount 52. The strut thrust bearing device 10 receives a load applied by the coil spring 53 to the first cover member 14. The upper surface is pressed against the upper mount 52. Moreover, the 1st cover member 14 has the cylinder part 14a extended in the axial direction downward on the inner peripheral side. A cylindrical portion 52b of the upper mount 52 is inserted into the inner peripheral surface of the cylindrical portion 14a, and the first cover member 14 is fixed to the upper mount 52. That is, the first track ring 11 is fixed to the upper mount 52 through the first cover member 14 attached integrally.

The second bearing ring 12 is formed by pressing from a steel plate in the same manner as the first bearing ring 11, and a track 12a on which the balls 13 roll is formed on the upper surface side. The second race ring 12, the first race ring 11, and the ball 13 constitute a thrust ball bearing. The contact angle with respect to the ball 13 is a predetermined value for the race 12a and the race 11a. It is set to be. Further, the balls 13 are arranged at equal intervals along both the tracks 11 a and 12 a by the cage 16.
The second race ring 12 has a third reinforcing rib portion 12d formed so as to extend in a cylindrical shape by bending an end portion 12c on the inner peripheral side substantially downward in the axial direction. The third reinforcing rib portion 12d is formed by bending an end portion 12c on the inner peripheral side of the second race ring 12, and for example, bent portions 12e, 12f, The portion formed by 12g is not included in the reinforcing rib portion.
Further, the second race ring 12 including the third reinforcing rib portion 12d is integrally attached while being in contact with the upper end portion on the inner peripheral side of the second cover member 15.

  The second cover member 15 is formed from the same resin or the like as the first cover member 14 and is integrated with the second raceway ring 12 along the lower surface of the second raceway ring 12 as described above. Is attached. The second cover member 15 has a cylindrical portion 15a that extends downward in the axial direction on the inner peripheral side thereof. The lower surface of the second cover member 15 has a flat portion 15b formed in a substantially flat surface, and the flat portion 15b and the outer peripheral surface of the cylindrical portion 15a are connected by a smooth concave curved surface. A curved surface portion 15c is formed. The curved surface portion 15c and the flat surface portion 15b constitute a sheet surface 15d with which the upper end of the coil spring 53 is in contact.

  In this manner, the strut thrust bearing device 10 is disposed between the upper mount 52 fixed to the vehicle and the coil spring 53, and receives the load from the coil spring 53 on the seat surface 15d while receiving the coil spring 53. The vehicle is swingably supported with respect to the vehicle.

According to the present embodiment configured as described above, both the race rings 11 and 12 of the thrust bearing device 10 for struts have the reinforcing rib portions 11b, 11c, and 12d formed by bending the end portions thereof. Therefore, the rigidity of both the race rings 11 and 12 can be improved without causing a large increase in weight.
Further, the second race ring 12 whose rigidity is enhanced by the reinforcing rib portion 12d acts as a reinforcement member that reinforces the second cover member 15 covering the lower surface of the second race ring 12, and as a result. The second cover member 15 can be reinforced to increase its rigidity.
Further, since the reinforcing rib portion 12d is formed to extend downward in the axial direction while being in contact with the second cover member 15 formed of resin, the contact area between the second race ring 12 and the second cover member 15 Can be increased. Thereby, the effect | action as a reinforcement member which the 2nd track ring 12 reinforces the 2nd cover member 15 is heightened, and the rigidity of the 2nd cover member 15 can be improved more.
The reinforcing rib portion only needs to be formed by bending the end portion on the inner peripheral side or the outer peripheral side, but the direction of the reinforcing rib portion is set in a range of 0 ° to 10 ° with respect to the axial direction. Further, it is more preferable that the angle is 0 ° with respect to the axial direction, that is, the third reinforcing rib portion 12d of the present embodiment is formed substantially parallel to the axial direction.
In this case, the reinforcing rib portion 12d is formed substantially parallel to the direction of the load from the coil spring 53 that acts on the thrust bearing device 10 for struts. As a result, the rigidity of the second race 12 can be further increased.

  As described above, the rigidity of the raceways 11 and 12 and the second cover member 15 can be increased without causing a significant increase in weight. Therefore, even if an unbalanced load from the coil spring 53 acts on the strut thrust bearing device 10, it is possible to suppress the deformation in the thrust direction, and the strut thrust bearing device 10 appropriately controls the coil spring 53. Can be supported.

  Next, a description will be given of the result of the FEM analysis verifying the deformation amount when the load is applied to the strut thrust bearing device 10 by the inventor. As an analysis model of the example, the thrust bearing device 10 for struts shown in the above-described embodiment, and as an analysis model of the comparative example, a thrust having a second race ring having no reinforcing rib portion shown in FIG. A bearing device was adopted. And about these analysis models, the FEM analysis was performed assuming the state where the load from the coil spring 53 acted at the time of vehicle mounting, the analysis model was deformed, the deformation state was quantified, and both were compared.

  FIG. 4 is a diagram illustrating an example of an analysis model obtained as a deformed state as a result of the FEM analysis. In the figure, a line A indicates a reference plane obtained by applying the least square method to an annular sheet surface in contact with a coil spring and in a deformed state. And by integrating the displacement in the vertical direction (thrust direction) between this reference plane and the sheet surface in the deformed state over the entire circumference, this integrated value is taken as the deformation amount (deflection amount) of the analysis model, The deformation state was quantified.

As a result, the amount of deflection calculated from the analysis model of the example was 7.1 mm, while the amount of deflection calculated from the analysis model of the comparative example was 8.2 mm or more. Thus, it was found that the amount of deflection by the analysis model of the example is smaller than that of the comparative example.
From the comparison result of the deflection amount calculated based on the above analysis model, the thrust bearing device of the present embodiment can improve the rigidity and suppress the deformation in the thrust direction by providing the reinforcing rib portion on the raceway ring. Was confirmed.

  In addition, this invention is not limited only to the said embodiment. For example, the reinforcing rib portion 11e of the first race 11 of the above embodiment is bent downward in the axial direction, but may be bent upward in the axial direction. Moreover, you may form a reinforcement rib part in the edge part of the outer peripheral side of a 2nd track ring. Moreover, the structure of the thrust bearing comprised by both the bearing rings and the balls, and the materials and shapes of the both bearing rings and the cover member can be appropriately changed based on the gist of the present invention.

It is a fragmentary sectional view of the strut upper end part using the thrust bearing device for struts which is one embodiment of the present invention. It is sectional drawing to which the thrust bearing apparatus 10 for struts in FIG. 1 was expanded. It is the fragmentary sectional view which showed the thrust bearing apparatus for struts of a comparative example. It is a figure which shows an example of the analysis model obtained as a result of having deformed as a result of performing FEM analysis about the thrust bearing device for struts.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Thrust thrust bearing apparatus 11 1st track ring 11b, 11d edge part 11c 1st reinforcement rib part 11e 2nd reinforcement rib part 12 2nd track ring 12c edge part 12d 3rd reinforcement rib part 13 ball ( Rolling element)
14 First cover member 15 Second cover member

Claims (5)

An annular first raceway,
An annular second race ring disposed opposite to the first race ring in the axial direction;
A plurality of rolling elements arranged so as to be freely rollable between the raceways;
Strut thrust bearing with
For struts, at least one of the bearing rings has a reinforcing rib portion formed by bending at least one of inner and outer end portions. Thrust bearing. An annular first raceway,
An annular second race ring disposed opposite to the first race ring in the axial direction;
A plurality of rolling elements arranged so as to be freely rollable between the raceways;
A cover member that is formed of a material that is less rigid than the bearing ring, and that covers the bearing ring;
In a thrust bearing device for struts comprising:
For struts, at least one of the bearing rings has a reinforcing rib portion formed by bending at least one of inner and outer end portions. Thrust bearing device.   The thrust bearing device for a strut according to claim 2, wherein the cover member is configured to receive a load of a coil spring that absorbs an impact from a wheel.   The thrust bearing device for a strut according to claim 2 or 3, wherein the reinforcing rib portion is bent substantially in an axial direction.   5. The strut thrust bearing device according to claim 2, wherein the reinforcing rib portion is provided so as to come into contact with the cover member.

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