JP2011052730A - Ball joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To buffer a tensile load acting between a housing and a stud part without lowering holding force with respect to a ball part of a bearing member. <P>SOLUTION: The ball joint includes: the housing 23 having an inner chamber 24 having first and second openings 24a, 24b; a bearing member 25 fit in the inner chamber; a ball stud 20 having the member 25 hold a ball part 22 and projecting the stud part 21 to a first opening 24a side; an annular receiving part fixed to the housing 23 and bearing one end of the bearing member 25; and a closing member 46 fit in and fixed to the second opening 24b. The receiving part is composed of a stop ring 40 having elasticity secured to an inner circumference of the housing 23, and by elastically deforming the stop ring 40 by pressing the bearing member 25 by the closing member 46, a set load energizing the bearing member 25 toward the closing member 46 is applied to the stop ring 40. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ball joint mainly used for a suspension device and a steering device of an automobile, and in particular, a housing having a cylindrical inner chamber opened with one end in the axial direction as a first opening and the other as a second opening. A synthetic resin bearing member fitted in the inner chamber of the housing, a ball portion held by the bearing member, and a ball stud comprising a stud portion protruding from the ball portion toward the first opening , A ball comprising an annular receiving portion provided on the housing for supporting one end portion of the bearing member, and a closing member fitted and fixed to the second opening portion so as to face the other end of the bearing member Regarding improvement of joints.

  Such a ball joint is already known as disclosed in Patent Document 1 below.

JP 2006-105306 A

  In such a conventional ball joint, as disclosed in Patent Document 1, the annular receiving portion that supports one end of the bearing member is formed integrally with the housing and has rigidity. When a tensile load is applied between the studs, the tensile load is transmitted and supported from the ball part to the receiving part via the bearing member, and is hardly buffered between them. It tends to occur, and its durability is impaired.

  Therefore, it is conceivable to provide the bearing member with elasticity that can relieve the tension load as described above. However, if this is done, the holding force of the bearing member with respect to the ball portion is reduced, which is not preferable.

  The present invention has been made in view of such circumstances, and is capable of buffering the tensile load acting between the housing and the stud portion without reducing the holding force of the bearing member with respect to the ball portion. The object is to provide a ball joint.

  In order to achieve the above object, the present invention is fitted to a housing having a cylindrical inner chamber opened with one axial end as a first opening and the other end as a second opening, and the inner chamber of the housing. A synthetic resin bearing member, a ball portion held by the bearing member and a stud stud projecting from the ball portion toward the first opening, and a housing provided on the housing. In a ball joint comprising an annular receiving portion for supporting one end portion and a closing member fitted and fixed to the second opening portion so as to be opposed to the other end of the bearing member, the receiving portion is connected to the housing. It is composed of a retaining ring having elasticity that is locked to the inner periphery, and by pressing the bearing member by the closing member and elastically deforming the retaining ring, That the serial bearing member to impart a set load that urges the closure member to the first feature.

  According to the present invention, in addition to the first feature, an auxiliary bearing member softer than the bearing member that is elastically compressed and deformed so as to be pressed against the top of the ball portion is provided between the ball portion and the bearing member. The second feature is that they are interposed.

  In addition to the second feature of the present invention, the third feature is that, when the ball joint is assembled, the deformation allowance of the auxiliary bearing member in the compression direction is set larger than the deformation allowance of the retaining ring in the bending direction. To do.

  Furthermore, in addition to the second feature of the present invention, the auxiliary bearing member includes a dish-shaped bearing portion interposed between the peripheral portion of the other pole of the ball portion and the bearing member. A fourth feature is that the bearing member is formed with a holding hole for holding the auxiliary bearing member, while the positioning cylinder portion projects from the central portion of the outer peripheral surface of the bearing portion toward the closing member.

  Furthermore, in addition to the first or third feature, the fifth feature of the present invention is that the retaining ring is made of a spring steel plate.

  According to the first feature of the present invention, when a tensile load acts between the stud portion and the housing from the outside and the load exceeds the set load of the retaining ring, the ball portion is accompanied by the bearing member and the retaining ring. Since the elastic deformation in the bending direction is applied to the bearing, the load can be buffered by the elastic deformation, and the wear of the bearing member due to the overload can be avoided and the durability of the ball joint can be improved. Moreover, since it is not necessary to give special elasticity to a bearing member, the strong holding force with respect to the ball | bowl part of a bearing member can be maintained.

  Moreover, the set load of the retaining ring can be easily adjusted by setting the fitting depth of the closing member with respect to the housing.

  Also, since the bearing member holding the ball stud ball part is fitted into the inner chamber of the housing from the ball part side, the stud part has a larger diameter than the inner diameter of the inner chamber, or there is a large member in the stud part. Even when connected together, the bearing member can be mounted on the housing together with the ball portion without being obstructed by them, and the assemblability is very good.

  According to the second feature of the present invention, since the auxiliary bearing member that is elastically compressed and deformed so as to be in pressure contact with the top of the ball portion is interposed between the ball portion and the bearing member, the initial elastic deformation amount of the auxiliary bearing member is reduced. That is, by selecting the set load, the swing torque of the ball stud can be set as desired. In addition, when a compressive load acts between the stud part and the housing from the outside and the compressive load exceeds the compression set load of the auxiliary bearing member, the ball part gives further compressive deformation to the auxiliary bearing member. The load can be buffered, the wear of the auxiliary bearing member and the bearing member due to overload can be avoided, and the durability of the ball joint can be improved.

  Moreover, since the auxiliary bearing member is made softer than the bearing member, the set load of the auxiliary bearing member can be set as desired with almost no interference with the bearing member, and the swing torque of the ball stud can be set as desired. It can be set easily.

According to the third feature of the present invention, sufficient elastic compression deformation is imparted to the auxiliary bearing member during the assembly of the ball joint to ensure that the necessary swing torque is imparted to the ball stud even when manufacturing the parts. can do.

  According to the fourth feature of the present invention, the auxiliary bearing member can be kept in pressure contact with the top of the ball portion without being displaced by fitting the positioning cylinder portion into the holding hole of the bearing member.

  According to the fifth feature of the present invention, since the retaining ring is made of a spring steel plate, the spring characteristics of the retaining ring are stabilized, and the retaining ring has a predetermined depth by selecting the fitting depth of the closing member into the housing. A set load can be easily applied.

The perspective view of the suspension device of the motor vehicle which uses the ball joint which concerns on one Example of this invention. FIG. 3 is an exploded perspective view around the ball joint in the suspension device. The expanded longitudinal cross-sectional view of the said ball joint. The side view of the bearing member in the said ball joint. FIG. 5 is a view taken in the direction of arrow 5 in FIG. 4. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. The top view of the retaining ring in the said ball joint. FIG. 4 is an explanatory diagram of the assembly procedure of the ball joint.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  First, referring to FIG. 1, a front suspension device of an FF type vehicle using the ball joint of the present invention will be described.

  The suspension device S includes an Al alloy knuckle 1 that rotatably supports a front wheel W, a bifurcated upper arm 2 that connects an upper portion of the knuckle 1 to a front portion of a vehicle body (not shown) so as to swing up and down, and a knuckle 1 The first and second lower arms 4a and 4b that connect the lower part to the sub-frame 3 of the vehicle body so as to be swingable up and down, and the damper that is interposed between the fork part of the upper arm 2 and between the second lower arm 4b and the front part of the vehicle body 5 and a coil spring 6 mounted on the upper portion of the damper 5 so as to expand and contract in accordance with the expansion and contraction of the damper 5.

  Further, the tie rod 8 of the steering device 7 is connected to the knuckle 1, and the knuckle 1 is rotated around the virtual kingpin axis A by the left and right movement of the tie rod 8 in accordance with the steering operation by the driver. The virtual kingpin axis A is such that the instantaneous center below it passes through the intersecting portion of the extension line of the first lower arm 4a and the extension line of the second lower arm 4b. The deviation (kingpin offset) between the intersection of the axis A and the road surface and the center of the front wheel W is significantly smaller than that of a normal suspension system.

  Further, the hub 10 of the front wheel W is held on the knuckle 1 via a hub bearing (not shown), and a drive shaft 11 driven by a power unit (not shown) is connected to the hub 10.

  As shown in FIG. 2, a substantially rectangular parallelepiped joint bracket 12 having a long side extending in the front-rear direction of the vehicle body is fastened to the lower surface of the knuckle 1 by a pair of front and rear bolts 13, 13. The upper end is connected to the outer end of the first lower arm 4a and the lower end is connected to the outer end of the second lower arm 4b via a pair of ball joints J, J according to the present invention. The pair of upper and lower ball joints J and J are offset from each other with a relatively short interval along the longitudinal direction of the vehicle body.

  Now, the configuration of the ball joint J according to the present invention will be described with reference to FIGS.

  As shown in FIGS. 2 and 3, the ball joint J is integrally formed with the ball stud 20 protruding integrally with the upper or lower surface of the joint bracket 12 and the outer end of the first lower arm 4a or the second lower arm 4b. And a housing 23 to be formed. In the following description, for the sake of convenience, the housing 23 side is the upper side and the ball stud 20 side is the lower side.

  The ball stud 20 includes a stud base 21a raised from the joint bracket 12 and a stud portion 21 having a smaller diameter neck portion 21b integrally connected thereto, and a ball portion integrally provided to the neck portion 21b. 22, and the stud base 21 a has a larger diameter than the ball portion 22. The ball portion 22 is held by a synthetic resin bearing member 25 having a cylindrical outer peripheral surface.

  The housing 23 has a cylindrical inner chamber 24. The inner chamber 24 is opened with the lower end in the axial direction as the first opening 24a and the upper end as the second opening 24b, and the bearing member 25 is closely fitted into the inner chamber 24 from the first opening 24a. The

  As shown in FIGS. 4 to 7, the bearing member 25 is adapted to the equator e of the ball portion 22 (a great circle on the ball portion 22 orthogonal to the axis y of the stud portion 21) and its peripheral portion on the inner peripheral side thereof. A spherical holding surface 27 is formed. An annular groove 28 extending along the equator e of the ball portion 22 is formed on the holding surface 27. A plurality of slits 29, 29... Extending from the one end on the first opening 24 a side beyond the holding surface 27 are provided on the peripheral wall of the bearing member 25 at equal intervals in the circumferential direction. Further, the outer peripheral surface of the upper end portion of the bearing member 25 is provided with a plurality of notched grooves 30, 30.

  An auxiliary bearing member 31 that is in pressure contact with the top of the ball portion 22 is interposed between the bearing member 25 and the ball portion 22. The auxiliary bearing member 31 includes a dish-shaped bearing portion 32 having a spherical pressure contact surface 33 that is in pressure contact with the top of the ball portion 22, and a positioning cylinder portion 34 that protrudes from the center of the outer peripheral surface of the bearing portion 32. The positioning cylinder portion 34 is provided with a through hole 35 penetrating the central portion thereof, and the pressure contact surface 33 is formed with radial grooves 36, 36... Extending from the through hole 35.

  A holding hole 37 for holding the auxiliary bearing member 31 is provided in the bearing member 25. The holding hole 37 includes a large-diameter hole 37a that extends from the upper edge of the holding surface 27 and fits the outer peripheral edge of the bearing portion 32, a small-diameter hole 37b that fits the positioning cylinder portion 34, and a large-diameter hole 37b. The hole 37a and the small diameter hole 37b are connected to each other and a tapered hole 37c for supporting the inclined outer peripheral surface of the bearing portion 32 is formed.

  Thus, the bearing portion 32 of the auxiliary bearing member 31 is given a predetermined tightening allowance in advance, and the ball portion 22 is held by the bearing member 25 so as to be in close contact with the holding surface 27 of the bearing member 25. The bearing portion 32 is elastically compressed and deformed by a predetermined amount between the bearing member 25 and the ball portion 22, and a predetermined compression set load is applied to the bearing portion 32. Thereby, the swing torque of the ball stud 21 is set.

  An annular locking groove 38 is provided on the inner peripheral surface of the housing 23 in the vicinity of the first opening 24a, and a retaining ring 40 made of a spring steel plate for supporting the lower end surface of the bearing member 25 is provided in the locking groove 38. Installed.

  As shown in FIGS. 3 and 8, the retaining ring 40 has a circlip shape having a single cut 41, and the opposite ends of the cut 41 are reduced in diameter and locked. Tool holes 42 are provided for tools to be used when mounting in the groove 38. The retaining ring 40 elastically engages with the engaging groove 38 on the inner peripheral surface of the bearing member 25, and supports the lower end surface of the bearing member 25 at a portion protruding from the engaging groove 38.

  In FIG. 3 again, an annular recess 44 having a diameter larger than that of the inner chamber 24 is provided on the inner peripheral surface of the second opening 24 b of the housing 23, and an annular caulking portion 45 is raised from the outer end edge of the annular recess 44. is doing. A closing member 46 is fitted into the annular recess 44. The closing member 46 closes the second opening 24b and presses the upper end surface of the bearing member 25 to impart a predetermined elastic bending deformation to the retaining ring 40. The caulking portion 45 is caulked inward in the radial direction so as to maintain the fitting state. Further, when the bearing member 25 deforms the retaining ring 40 by pressing from the closing member 46, the bearing member 25 simultaneously compresses the bearing portion 32 of the auxiliary bearing member 31 and presses it against the ball portion 22.

  By the way, the bearing member 25 is made of a relatively hard synthetic resin such as polyacetal, and can exert a large holding force with respect to the ball portion 22, and the auxiliary bearing member 31 is made of, for example, a polyester elastomer. The bearing member 25 is made of a synthetic resin that is softer than the bearing member 25, and can regulate the swing torque of the ball portion 22 and absorb the impact force from the ball portion 22.

  Thus, when the ball joint J is assembled, the deformation allowance of the auxiliary bearing member 31 in the compression direction is set larger than the deformation allowance of the retaining ring 40 in the bending direction.

  A flexible boot 47 covering the periphery of the first opening 24 a of the housing 23 is stretched between the stud portion 21 and the housing 23. That is, the boot 47 includes a bellows portion 47a and annular first and second lip portions 47b and 47c formed at both ends in the axial direction. The first lip portion 47b is an outer peripheral surface of the stud base 21a. The second lip portion 47c is mounted in an annular lip mounting groove 48 provided on the outer peripheral surface of the housing 23 on the side of the first opening 24a.

  Next, the operation of this embodiment will be described.

  The assembly procedure of the ball joint J will be described with reference to FIGS. 3 and 9. First, the first lip 47b of the boot 47 is press-fitted into the stud base 21a, and then the cut ring 41 of the stop ring 40 is opened, and the stop ring 40 is inserted into the stud. Wait around the part 21.

  Next, grease is applied to the outer peripheral surface of the ball portion 22, and grease is also applied to the inner peripheral surface of the ball member 22 with the auxiliary bearing member 31 fitted to the bearing member 25. These greases are held in the annular groove 28 of the bearing member 25, the through hole 35 of the auxiliary bearing member 31 and the radial grooves 36, 36... Between the ball portion 22, the bearing member 25 and the auxiliary bearing member 31. It is used for lubrication of sliding parts.

  Then, the ball portion 22 is pushed into the opening of the bearing member 25 opposite to the auxiliary bearing member 31. Thus, since the peripheral wall of the bearing member 25 is provided with a plurality of slits 29, 29... Extending from the opening end of the bearing member 25 beyond the spherical holding surface 27, according to the pushing force of the ball portion 22. ., So that the peripheral wall of the bearing member 25 expands in a conical shape so that the slits 29, 29... Expand and receive the ball portion 22, and then the bearing surface 25 comes into close contact with the ball portion 22. However, since the bearing portion 32 of the auxiliary bearing member 31 is provided with a predetermined tightening allowance as described above, the ball portion 22 is a bearing before compression deformation. It is obstructed by the portion 32 and is fitted to the holding surface 27 in an incomplete state. Therefore, the peripheral wall of the bearing member 25 is slightly expanded in a conical shape.

  Then, when the bearing member 25 is fitted into the inner chamber 24 of the housing 23 together with the ball portion 22 from the first opening 24a side, that is, the locking groove 38 side, the conical diameter-enlarged portion of the bearing member 25 is obtained. Is reduced in diameter by the inner peripheral surface of the inner chamber 24, and the ball portion 22 compresses the bearing portion 32 with the bearing member 25 while being forcibly pushed into contact with the holding surface 27. Go. Thus, a compression set load is applied to the auxiliary bearing member 31. At this time, since the auxiliary bearing member 31 is made of a softer synthetic resin than the bearing member 25, the set load of the auxiliary bearing member 31 can be set as desired without being substantially interfered with the bearing member 25. The swing torque of the ball stud 21 can be easily set as desired.

  After the fitting of the bearing member 25 into the inner chamber 24 proceeds and the bearing member 25 passes through the locking groove 38, the retaining ring 40 is attached to the locking groove 38. Since the diameter of the peripheral wall of the bearing member 25 fitted in the inner chamber 24 of the housing 23 is blocked by the inner peripheral surface of the inner chamber 24, the ball portion 22 is firmly held by the holding surface 27. Exit from 25 is prevented.

  Next, the bearing member 25 is placed on the retaining ring 40 locked in the locking groove 38, and the closing member 46 is fitted into the annular recess 44 of the housing 23, and this closing member 46 is the bottom surface of the annular recess 44. The closing portion 46 is fixed to the housing 23 by caulking the caulking portion 45 of the housing 23 radially inward so as to be in close contact with the housing 23.

  Thus, the caulking force applied to the closing member 46 of the caulking portion 45 is transmitted to the retaining ring 40 via the bearing member 25 and given a predetermined elastic bending deformation to give a predetermined set load. Become. At that time, the bearing member 25 is slightly elastically compressed and deformed, and the holding force for the ball portion 22 is increased in cooperation with the auxiliary bearing member 31.

  After fixing the closing member 46, the second lip 47c of the boot 47 is mounted in the lip mounting groove 48 of the housing 23, and the assembly of the ball joint J is completed.

  As described above, in this ball joint J, the bearing member 25 mounted on the ball portion 22 is fitted into the inner chamber 24 of the housing 23 from the ball portion 22 side. Even if the stud base portion 21a has a larger diameter than the inner diameter of the inner chamber 24 or a large member such as the joint bracket 12 is integrally connected to the stud portion 21, the bearing member 25 is not disturbed. It can be mounted on the housing 23 together with the ball portion 22.

  While the automobile is running, a load is applied to the ball joint J from all directions depending on the operating state of the suspension device S. Thus, the bearing member 25 in the housing 23 is strongly held between the retaining ring 40 and the closing member 46 due to the set load of the retaining ring 40, so that the bearing member 25 rattles in the housing 23. In addition, the ball portion 22 is urged below the holding surface 27 by the compression set load of the auxiliary bearing member 31, so that the ball portion 22 is not rattled in the bearing member 25. Therefore, the ball joint J can smoothly swing with a predetermined torque without rattling between the housing 23 and the ball stud 20 in a normal load state.

  Moreover, the set load of the retaining ring 40 can be easily adjusted by setting the depth of the annular recess 44 of the housing 23, in other words, the depth of fitting of the closing member to the housing 23.

  Furthermore, since the auxiliary bearing member 31 has its positioning cylinder portion 34 fitted in the small diameter hole 37b of the holding hole 37 of the bearing member 25, the auxiliary bearing member 31 can be kept in pressure contact with the top of the ball portion 22 without being displaced. .

  By the way, when a tensile load acts between the stud portion 21 and the housing 23 from the outside and the tensile load exceeds the set load of the retaining ring 40, the ball portion 22 is attached to the retaining ring 40 with the bearing member 25. Since the elastic deformation in the bending direction is given, the tensile load can be buffered by the elastic deformation.

  Further, when a compression load acts between the stud portion 21 and the housing 23 from the outside and the compression load exceeds the compression set load of the auxiliary bearing member 31, the ball portion 22 gives further elastic compression deformation to the bearing portion 32. Therefore, the compressive load can be buffered by the elastic compressive deformation.

  As described above, the wear of the bearing member 25 due to overload can be avoided, and the durability of the ball joint J can be improved. Moreover, since it is not necessary to give special elasticity to the bearing member 25, the strong holding force with respect to the ball | bowl part 22 of the bearing member 25 can be maintained.

  By the way, when the ball joint J is assembled, the deformation allowance in the compression direction of the auxiliary bearing member 31 is set larger than the deformation allowance in the bending direction of the retaining ring 40 at that time. Sufficient compressive deformation can be imparted to the member 31 to reliably impart the necessary swing torque to the ball stud 21.

  Further, since the retaining ring 40 is made of a spring steel plate, the spring characteristics of the retaining ring 40 are stabilized, and a predetermined set load can be easily applied to the retaining ring 40 by selecting the fitting depth of the closing member 46 to the housing 23. Can be granted.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the scope of the present invention.

J ... Ball joint 20 ... Ball stud 21 ... Stud portion 22 ... Ball portion 23 ... Housing 24 ... Inner chamber 25 ... Bearing member 31 ... Auxiliary bearing member 32 ... Bearing part 33 ... Pressure contact surface 37 ... Holding hole 40 ... Stop ring 46 ... Closing member

Claims (5)

A housing (23) having a cylindrical inner chamber (24) opened with one end in the axial direction as a first opening (24a) and the other end as a second opening (24b), and an inner chamber ( 24) a synthetic resin bearing member (25) to be fitted to the bearing member (25), a ball part (22) held by the bearing member (25), and the first opening part (24a) side from the ball part (22) A ball stud (20) comprising a stud portion (21) projecting into the housing, an annular receiving portion provided on the housing (23) for supporting one end of the bearing member (25), and the bearing member (25) In a ball joint comprising a closing member (46) fitted and fixed to the second opening (24b) to face the other end of
The receiving portion is constituted by an elastic retaining ring (40) that is latched to the inner periphery of the housing (23), and the bearing member (25) is pressed by the closing member (46) to form the retaining ring. A ball joint characterized in that a set load for urging the bearing member (25) toward the closing member (46) is applied to the retaining ring (40) by elastically deforming (40). The ball joint according to claim 1,
An auxiliary bearing member (31) softer than the bearing member (25), which is elastically compressed and deformed so as to be pressed against the top of the ball portion (22), is interposed between the ball portion and the bearing member. A ball joint characterized by The ball joint according to claim 2,
A ball joint characterized in that, when the ball joint (J) is assembled, a deformation margin in the compression direction of the auxiliary bearing member (31) is set larger than a deformation margin in the bending direction of the retaining ring (40). The ball joint according to claim 2,
The auxiliary bearing member (31) includes a dish-shaped bearing portion (32) interposed between a peripheral portion of the other pole of the ball portion (22) and the bearing member (25), and the bearing portion. The positioning cylinder portion (34) projecting toward the closing member (46) side from the central portion of the outer peripheral surface of (32), and the holding hole (34) for holding the auxiliary bearing member (31) is formed in the bearing member. A ball joint formed in (25). The ball joint according to claim 1 or 3,
A ball joint characterized in that the retaining ring (40) is made of a spring steel plate.

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