JP4517399B2 - Thrust ball bearing for suspension upper support - Google Patents

Description

  The present invention relates to a thrust ball bearing for a suspension upper support.

Noto 2501751 gazette

  In the suspension connecting the wheel and the vehicle body, a thrust ball bearing is used for the upper support. This thrust ball bearing swings and rotates in a fixed angle range in both the left and right directions corresponding to the steering operation angle (Patent Document 1).

  Here, the thrust ball bearing described above is one of the factors governing the straight running stability of the suspension, and if the straight running stability is not good, the steering shakes or fluctuates due to fine vibration that reflects the undulation state of the road surface. Sometimes. In addition, in the case of a suspension with poor straight running stability, there is a problem that wobbling tends to occur even when the steering wheel is largely turned and then returned to the straight running state.

  An object of the present invention is to provide a thrust ball bearing for a suspension upper support that contributes to improving the straight running stability of a steering.

Means for Solving the Problems and Effects of the Invention

The thrust ball bearing for suspension upper support of the present invention for solving the above problems is
Balls forming a plurality of rolling elements arranged in the rotational circumferential direction between the first and second race rings arranged opposite to each other in the axial direction of the bearing, and the first and second race rings. And a retainer for holding the arrangement interval of these balls at a predetermined value, and the neutral point of the first race ring relative to the second race ring is predetermined with respect to the relative rotational angular position. At the same time, the first race ring swings and rotates within a predetermined upper limit swing angle range in both forward and reverse directions with respect to the second race ring with respect to the neutral point,
On at least one of the raceway surfaces of the first raceway and the second raceway, a part of the section set smaller than the upper limit swing angle range is a section in which the sliding resistance of the ball with respect to the raceway remains. While the low sliding resistance section is set smaller than, a predetermined one of a plurality of balls is determined as a torque control ball,
In a state where the first race ring is at the neutral point with respect to the second race ring, the torque control ball is located in the low sliding resistance section, and the first race ring is located between the neutral point and the low slide resistance section. The torque control ball is allowed to escape from the low sliding resistance section by swinging and rotating at an escape angle or more determined according to the length.

  The upper limit swing angle is determined in accordance with the allowable steering angle of the wheel, and is generally set in a range of less than 90 °, for example, 40 ° to 50 °. According to the thrust ball bearing for suspension upper support of the present invention, the neutral point is also determined in the relative rotation angle phase of the two race rings constituting the thrust ball bearing, corresponding to the steering neutral point when traveling straight. On the other hand, a low sliding resistance section is provided on at least one of the raceways of the second raceway with respect to the first raceway, and a part of the balls constituting the rolling elements are determined as torque control balls. The torque control ball is located in the low sliding resistance section at the neutral point, and the torque control ball escapes from the low sliding resistance section by rotating a certain angle from the neutral point with steering. did. As a result, the rotational sliding resistance of the thrust ball bearing and thus the rotational torque of the steering wheel are minimized at the neutral point. On the other hand, if the torque control ball escapes from the low sliding resistance zone with steering, the rotational torque of the steering wheel increases. The reaction becomes a restoring force, and the steering can be held at the neutral point. As a result, even if fine vibrations or the like due to road surface unevenness occur, it is difficult for the steering to sway, and the straight running stability can be greatly increased. Further, even when the steering wheel is largely turned and returned to the straight traveling state, it can be quickly stabilized at the neutral point, and fluctuation or the like hardly occurs.

  Radial restricting means for restricting the movement of the balls in the radial direction along the circumferential direction of the raceway surface is formed at the radial direction end of the raceway surface. The aforementioned low sliding resistance section can be formed, for example, by setting the radial width of the raceway surface to be larger than the remaining section. As the radial width of the raceway increases, the radial clearance formed between the ball on the raceway and the radial restricting means also increases, so the probability of sliding contact between the ball and the raceway decreases and the low It can function as a sliding resistance section.

  Next, a plurality of balls can be used as a torque control ball, but by providing a plurality of torque control balls, the torque minimum point depth at the neutral point increases, and at the neutral point. It is possible to further improve the steering stability.

  In this case, in a state where the first track ring is at the neutral point, a plurality of torque control balls can be positioned with respect to the same low sliding resistance section. By collecting multiple torque control balls in one low sliding resistance section, the overall shape of the raceway surface can be simplified and manufactured compared to separate low sliding resistance sections for multiple torque control balls. Is easy and smoother sliding characteristics can be obtained. In addition, since a plurality of torque control balls enter and exit sequentially with respect to the low sliding resistance section, the rotational sliding torque gradually increases and decreases according to the number of torque control balls entering and exiting. The torque change with the movement is also smooth, so there is little discomfort during steering.

  In this case, the arrangement interval of the plurality of torque control balls can be set narrower than the arrangement interval of the remaining balls. In this way, the sliding resistance outside the low sliding resistance section of the torque control ball train with a reduced arrangement interval is increased, and a sharper torque minimum point can be formed at the neutral point. Therefore, steering at the neutral point is possible. Is further improved. In this case, if a plurality of torque control balls are arranged closely in a single pocket by a cage, the above-described effects can be further enhanced, and the assembly process of the bearing can be simplified.

Embodiments of the present invention will be described below with reference to the drawings.
1 and 2 are cross-sectional views showing an example of a suspension ball bearing for suspension upper support (hereinafter also simply referred to as a thrust ball bearing) to which the present invention is applied. As shown in FIG. 1, the thrust ball bearing 1 is provided on an upper part of a strut suspension used in a vehicle such as an automobile, and the upper end portion of the strut pin rod 31 so as to rotate integrally with the strut pin rod 31. The upper case 3 is combined with the upper case 3. On the lower surface side of the upper case 3, the first track ring 5 is integrated in a shape surrounding the rotation axis of the strut pin rod 31. A lower case 4 is disposed below the upper case 3. As shown in FIG. 2, the lower case 4 is configured as an integral injection-molded part made of fiber reinforced resin, and a cylindrical case body 4m in which the insertion hole 8 of the strut pin rod 31 is formed to penetrate in the axial direction. The case main body 4m is formed in a flange shape protruding outward in the radial direction from the outer peripheral surface of the case body 4m, and has a bearing ring mounting protrusion 4s having a bearing ring mounting recess 4g on the upper surface side. As shown in FIG. 1, the lower case 4 is axially formed in such a manner that the relative rotation of the strut pin rod 31 is allowed by an elastic support mechanism 40 disposed below the upper case 3 and outside the strut pin rod 31. Elastically supported from the lower side. The second raceway ring 6 is attached to the raceway mounting recess 4g of the lower case 4 in a shape surrounding the rotation axis of the strut pin rod 31. A plurality of balls 2 are arranged between the first raceway ring 5 and the second raceway ring 6.

  The strut suspension shown in FIG. 1 includes a coil spring seat 25 that holds a spring seat 24 of a string spring 23, a shock absorber 30, and a thrust ball bearing 1 that is fitted to an upper end portion of a strut pin rod 31 of the shock absorber 30. A nut 26 for fixing the thrust ball bearing 1 at the upper part of the thrust ball bearing 1, a strut mount rubber 22 that holds the thrust ball bearing 1 so as to surround it, a strut support 21, and the like are included. The string spring 23, the spring seat 24 and the coil spring seat 25 constitute an elastic support mechanism 40.

  The shock absorber 30 includes a cylinder 32 and a strut pin rod 31 extending from a piston housed in the cylinder 32. Further, a bound stopper 28 made of a porous elastic body such as foamed urethane rubber is provided on the outer periphery of the strut pin rod 31. When the cylinder 32 is raised, the bound stopper 28 abuts against the piston rod protruding side end surface 32S of the cylinder 32 and is elastically compressed and deformed in the axial direction, so as to absorb impact energy and reduce impact sound. That is, in order to prevent the cylinder 32 from moving excessively, the bound stopper 28 such as foamed urethane rubber is attached to the strut pin rod 31.

  The thrust ball bearing 1 is disposed between the strut mount rubber 22 and the coil spring seat 25. The strut mount rubber 22 is fixed to the strut pin rod 31 and is disposed so as to cover the upper case 3 of the thrust ball bearing 1. The coil spring seat 25 is an annular plate-like support body supported by the upper end portion of the spring seat 24 on the lower surface of the outer peripheral portion 25a, and supports the lower case 4 of the thrust ball bearing 1 on the upper surface of the inner peripheral portion 25b. To do. A strut pin rod 31 is inserted into the inner peripheral surfaces 7 and 8 of the upper case 3 and the lower case 4, and the upper case 3 rotates relative to the lower case 4 integrally with the strut pin rod 31. A seal ring 17 (for example, made of rubber) is disposed between the inner peripheral surface (insertion hole) 8 of the lower case 4 and the outer peripheral surface of the strut pin rod 31.

  Next, as shown in FIG. 2, between the first raceway ring 5 and the second raceway ring 6, balls 2 that form a plurality of rolling elements arranged in the rotational circumferential direction, and the arrangement interval between these balls 2. Is disposed at a predetermined value. As shown in FIG. 3, a neutral point M is predetermined with respect to the rotational angle position of the first track ring 5 relative to the second track ring 6, and the second track ring 6 has a neutral point M. As a reference, it swings and rotates with respect to the first track ring 5 in the forward and reverse directions in an upper limit swing angle range 2θ of less than 90 ° (for example, 45 °) (θ in each of the forward and reverse directions).

  As shown in FIGS. 6, 7, and 8, at least one raceway surface RS of the first raceway ring 5 and the second raceway ring 6 is set to be smaller than the upper limit swing angle range 2θ. A low sliding resistance section 50 in which the sliding resistance of the ball with respect to the raceway surface RS is set to be smaller than the remaining section is formed in a partial section. The low sliding resistance section 50 may be formed on the first track ring 5 side as shown in FIG. 6, or may be formed on the second track ring 6 side as shown in FIG. As shown in FIG. 8, it may be formed on both the first raceway ring 5 and the second raceway ring 6. Hereinafter, the case where it is provided on the second race ring 6 will be described as a representative.

  As shown in FIG. 4, the plurality of balls 2 are determined in advance as torque control balls 2 '. In a state where the first raceway ring 5 is at the neutral point M with respect to the second raceway ring 6, the torque control ball 2 ′ is located in the low sliding resistance section 50, and the first raceway ring 5 is The torque control ball 2 ′ escapes from the low sliding resistance section 50 by swinging and rotating from the neutral point M at an escape angle or more determined according to the length of the low sliding resistance section 50. .

  According to the above configuration, the neutral point M is also determined in the relative rotational angle phase of the two race rings constituting the thrust ball bearing 1 corresponding to the steering neutral point during straight traveling shown in FIG. On the other hand, the above-mentioned low sliding resistance section 50 is provided on the raceway surface RS, and, as shown in FIG. 5A, the torque control ball 2 ′ is rotated at a certain angle from the neutral point M as a result of steering. Escape from the dynamic resistance section 50. As a result, the rotational sliding resistance of the thrust ball bearing 1 and thus the rotational torque of the steering are minimized at the neutral point M. On the other hand, if the torque control ball 2 'escapes from the low sliding resistance section 50 with steering, the rotation of the steering is performed. Since the torque increases, the reaction becomes a restoring force, and the steering can be held at the neutral point M. As a result, even if fine vibration due to road surface unevenness or the like occurs, it is difficult for the steering to sway, and straight running stability can be greatly increased. Further, even when the steering wheel is largely turned and then returned to the straight traveling state, the neutral point M can be quickly stabilized, and fluctuation or the like is hardly generated.

  As shown in FIG. 2, radial restricting means for restricting movement of the balls 2 in the radial direction along the circumferential direction of the raceway surface RS is formed at the radial direction end of the raceway surface RS. In FIG. 6, FIG. 7 and FIG. 8, the low sliding resistance section 50 is formed, for example, with the radial width of the raceway surface RS set larger than the remaining section. Moreover, in this embodiment, as shown in FIG. 2, the cross-section of the raceway surface RS is formed in an arc shape, and both edges of the raceway surface RS that bends following the ball form a radial restricting hand. Is clear (however, the cross-sectional shape of the raceway surface RS is not limited to this). As shown in FIG. 5B, if the radial width of the raceway surface RS increases in the low sliding resistance section 50, the radial clearance formed between the balls 2 and both edges of the raceway surface RS also increases. The probability of sliding contact between the ball 2 and the race 6 can be reduced and function as the low sliding resistance section 50.

  As shown in FIG. 12, the low sliding resistance section 50 can be formed such that its outer peripheral edge 50 </ b> A protrudes outward in the radial direction from the outer peripheral edge of the remaining section. Further, as shown in FIG. 13, the low sliding resistance section 50 can be formed such that its inner peripheral edge 50B protrudes radially inward from the inner peripheral edge of the remaining section. Furthermore, as a combination of both, as shown in FIG. 4, both the outer peripheral edge 50 </ b> A and the inner peripheral edge 50 </ b> B can be formed so as to protrude. Specific examples are as follows.

  In FIG. 12, the low sliding resistance section 50 is formed in a shape in which the outer peripheral edge 50 </ b> A bulges outwardly in a form of an arc having a smaller radius of curvature than the outer peripheral edge of the remaining section. . Further, in FIG. 13, the low sliding resistance section 50 is formed in a shape in which its inner peripheral edge 50B is bulged inwardly in a form of an arc having a smaller radius of curvature than the inner peripheral edge of the remaining section. Yes. The inner peripheral edge may be a reverse arc segment 50B or a straight segment 50BS.

  In FIG. 14, the low sliding resistance section 50 forms an arc shape having a larger curvature radius than the remaining section, with the outer peripheral edge 50C sharing the center of curvature radius with the outer peripheral edge of the remaining section. It is formed in a shape protruding outward. Further, at both ends, a connection section 50j with the outer peripheral edge of the remaining section is formed so as to gradually reduce the radius of curvature toward the end of the remaining section. On the other hand, in FIG. 15, the low sliding resistance section 50 has an arc shape having a smaller radius of curvature than the remaining section, with the inner peripheral edge 50 </ b> D sharing the center of curvature radius with the inner peripheral edge of the remaining section. It is formed in a shape protruding inward. Further, at both ends thereof, a connection section 50j with the outer peripheral edge of the remaining section is formed so as to gradually increase the radius of curvature toward the end of the remaining section. FIG. 16 corresponds to a combination of the two. In FIG. 17, the low sliding resistance section 50 has its outer peripheral edge 50E extended outwardly in a cusp shape in a linear form extending tangentially from the outer peripheral end position of the remaining section. It is formed with.

  Next, in the thrust bearing 1 of FIG. 2, as shown in FIG. 4, in the state where the first bearing ring 5 is at the neutral point M, a plurality (here, Three) torque control balls 2 ′ are positioned. In this case, at the neutral point M, the torque control ball 2 ′ located near the end of the low sliding resistance section 50 escapes from the low sliding resistance section 50 with a smaller sliding angle. That is, as shown in FIG. 5A, when the steering is displaced from the neutral point M, the plurality of torque control balls 2 ′ escape from the section 50 in order from the end near the displacement direction end of the low sliding resistance section 50. However, when the displacement returns to the neutral point, it returns to the section 50 in the reverse order. In other words, the rotational sliding torque increases or decreases stepwise according to the number of torque control balls 2 ′ entering and exiting, and the torque change associated with the sliding becomes smooth. Therefore, there is an advantage that there is less discomfort during steering.

  In FIG. 5A, the arrangement interval of the plurality of torque control balls 2 ′ is set narrower than the arrangement interval of the remaining balls 2. As shown in FIG. 3, the arrangement interval of the balls 2, 2 ′ can be regulated by the formation interval of the pockets 21 p, 21 s that accommodate the balls 2, 2 ′ formed in the holder 20. Since the sliding resistance outside the low sliding resistance section 50 of the torque control balls 2 'row with a reduced arrangement interval is increased, and a sharper torque minimum point can be formed at the neutral point M, steering at the neutral point M is possible. Is further improved. In FIG. 3, a plurality of torque control balls 2 ′ are arranged in close contact with each other in a single pocket 21 p by the cage 20.

  9 (the cage side) and FIG. 10 (the race ring side), and FIG. 18 (the cage side) and FIG. 19 (the race ring side), respectively, the low sliding resistance section 50 is the raceway surface. It is possible to form a dispersion at a plurality of locations in the circumferential direction of the RS, and distribute the torque control balls 2 ′ to each of the plurality of low sliding resistance sections 50. As a result, the total number of torque control balls 2 ′ involved in the low sliding resistance section 50 can be further increased, which can contribute to the sharpening of the torque minimum point formed at the neutral point. 9 and 10, a plurality of torque control balls 2 ′ are distributed to each low sliding resistance section 50. In FIGS. 18 and 19, a plurality of torque control balls 2 are arranged in the low sliding resistance section 50. An example of distributing 'is shown.

  As shown in FIG. 5A, when the swing angle of the bearing 1 is increased, the torque control balls 2 ′ located in the low sliding resistance section 50 at the neutral point are sequentially escaped from the swing end portion. However, instead, at the end on the opposite side, the ball 2 that was not in the low sliding resistance section 50 at the neutral point gradually approaches. When the ball 2 newly enters the low sliding resistance section 50 when it rotates to the vicinity of the upper limit swing angle, FIGS. 11A and 11B show an upper limit swing angle range 2θ centered on the neutral point M. An example in which balls 2 other than the torque control ball 2 'are excluded from the inner section is shown.

  Further, as shown in FIG. 20, the low sliding resistance section 50 can be formed as a recess 50X in which a part of the raceway surface RS is recessed in the axial direction.

The longitudinal view which shows the 1st Example of the thrust ball bearing for suspension upper supports of this invention with the peripheral part. The longitudinal cross-sectional view which expands and shows the thrust ball bearing of FIG. The top view which extracts and shows the ball | bowl and cage | basket part of FIG. The top view which extracts and shows the ball | bowl of FIG. 2, and a 2nd track ring. Action explanatory drawing of the thrust ball bearing of FIG. Explanatory drawing of the radial control means in the thrust ball bearing of FIG. The perspective view which shows the example which provided the low sliding resistance area only in the 1st track ring side. The perspective view which shows the example which provided the low sliding resistance area only in the 2nd track ring side. The perspective view which shows the example which provided the low sliding resistance area in both the 1st track ring side and the 2nd track ring side. The top view which extracts and shows the ball | bowl and the holder | retainer part in the 1st of the example which provided multiple low sliding resistance area. The top view which extracts and shows the ball | bowl and the 2nd track ring in the 1st of the example which provided multiple low sliding resistance area. FIG. 4 is a first diagram illustrating a configuration example in which balls other than torque control balls are excluded from a section within an upper limit swing angle range in FIG. 3. Similarly second figure. The top view which shows the 1st example of the low sliding resistance area formed by extending the raceway surface in the radial direction. The top view which similarly shows a 2nd example. The top view which similarly shows a 3rd example. The top view which similarly shows a 4th example. The top view which similarly shows a 5th example. The top view which similarly shows a 6th example. The top view which extracts and shows the ball | bowl and the holder | retainer part in the 2nd of the example which provided multiple low sliding resistance area. The top view which extracts and shows the ball | bowl and the 2nd track ring in the 2nd of the example which provided multiple low sliding resistance area. The figure which shows the example which formed the low sliding resistance area as a recess which dented a part of raceway surface to the axial direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thrust ball bearing for suspension upper support 2 Ball 2 'Torque control ball 5 First race ring 6 Second race ring 20 Cage RS Raceway surface M Neutral point 50 Low sliding resistance section

Claims (7)

Balls forming a plurality of rolling elements arranged in the rotational circumferential direction between the first and second race rings arranged opposite to each other in the axial direction of the bearing, and the first and second race rings. And a retainer that holds the arrangement intervals of the balls at a predetermined value, and the first raceway has a neutral point with respect to the rotational angle position relative to the second raceway in advance. And the first race is oscillated and rotated within a predetermined upper limit oscillating angle range in both forward and reverse directions with respect to the second race with respect to the neutral point,
On at least one of the raceway surfaces of the first raceway and the second raceway, a partial section set smaller than the upper limit swing angle range has a sliding resistance of the ball with respect to the raceway surface. While the low sliding resistance section is set smaller than the remaining section, a predetermined one of the plurality of balls is determined as a torque control ball,
In a state where the first track ring is at the neutral point with respect to the second track ring, the torque control ball is located in the low sliding resistance section, and the first track ring is moved from the neutral point. The suspension upper characterized in that the ball for torque control is allowed to escape from the low sliding resistance section by swinging and rotating at an escape angle or more determined according to the length of the low sliding resistance section. Thrust ball bearing for support. Radial restricting means for restricting movement of the balls in the radial direction along the circumferential direction of the raceway surface is formed at a radial direction end of the raceway surface, and the low sliding resistance section is the track. The thrust ball bearing for suspension upper support according to claim 1, wherein the radial width of the surface is set larger than the remaining section. The thrust ball bearing for suspension upper support according to claim 1, wherein a plurality of the torque control balls are provided. The thrust ball bearing for suspension upper support according to claim 3, wherein a plurality of torque control balls are positioned with respect to the same one in the low sliding resistance section in a state where the first race ring is at the neutral point. The thrust ball bearing for suspension upper support according to claim 4, wherein an arrangement interval of the plurality of torque control balls is set to be narrower than an arrangement interval of the remaining balls. The thrust ball bearing for a suspension upper support according to claim 5, wherein the plurality of torque control balls are closely arranged in a single pocket by the cage. The low sliding resistance section is dispersed formed at a plurality of positions in the circumferential direction of the raceway surface, the plurality of each of the torque control ball is distributed name Ru請 Motomeko 1 to claims low sliding resistance section The thrust ball bearing for suspension upper support according to any one of items 6.

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