JP2016031079A - Ball joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball joint capable of securing sealing performance while suppressing abrasion of a dust cover due to contact with a mating member in rocking of a ball stud.SOLUTION: A bent portion 55 is provided on at least one portion between both ends in an axial direction of a cylindrical dust cover body 51 of a duct cover 24. Tightening force to tighten a stud 32 of a first lip 52 provided on one end side in the axial direction of the dust cover body 51 makes larger than tightening force to tighten a housing 23 of a second lip 53 provided on the other end side in the axial direction of the dust cover body 51. The first lip 52 surely flows the stud 32 in rocking of a ball stud 21 so as to restrain sliding with a knuckle 12, and abrasion of the dust cover 24 due to contact with the knuckle 12 can be suppressed. Force generated in deformation of the dust cover 24 in accordance with rocking of the ball stud 21 is concentrated on the bent portion 55, and the second lip 53 is prevented from coming off the housing 23, and sealing performance can be secured.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a ball joint that is partially clamped and fixed to a counterpart member by a clamp portion.

  Conventionally, a ball joint used for a suspension device of a vehicle such as an automobile has a ball stud having a ball portion and a stud portion that is a shaft portion protruding from the ball portion, and the ball portion of the ball stud can be rotated. A cylindrical ball sheet that is a bearing sheet made of synthetic resin or the like to hold, and a housing such as a bottomed cylinder that has an inner chamber that receives the ball sheet that holds the ball portion on the sliding contact surface and is integral with the lower arm; A cylindrical dust cover is provided to cover the space between the ball stud and the housing. And this ball joint is connected with the knuckle which the stud part of a ball stud is a counter member, for example.

  For connecting the stud portion of the ball stud and the knuckle, for example, the stud portion is inserted into an insertion hole provided in the knuckle and fixed with a nut or the like (for example, see Patent Document 1), and the insertion hole is continuous. In some cases, a pair of clamp portions divided by slits are provided, and a stud portion inserted into an insertion hole is sandwiched by tightening the clamp portion with a bolt (pinch bolt) (see, for example, Patent Document 2).

Japanese Utility Model Laid-Open No. 2-2413 (2nd page, FIG. 2) Japanese Patent No. 3421480 (page 3-4, FIGS. 1-4)

  Normally, the dust cover slides the inner periphery of the ball stud side, which is the smaller diameter side, against the outer peripheral surface of the stud portion in order to prevent twisting due to the rotational movement of the knuckle integrally connected to the stud portion of the ball stud. It is common to move. However, for example, in the configuration in which the stud portion is sandwiched by the clamp portion as in the configuration described in Patent Document 2, when the knuckle rotates, the ball stud side of the dust cover and the contact surface of the knuckle come into sliding contact with each other, and the dust at the edge of the slit. The cover may be worn or damaged.

  Such a problem occurs not only for a ball joint for a vehicle but also for an arbitrary ball joint that sandwiches a stud portion by a clamp portion.

  The present invention has been made in view of these points, and an object of the present invention is to provide a ball joint that can ensure sealing performance while suppressing wear of a dust cover due to contact with a mating member when the ball stud swings. And

  The ball joint according to claim 1 is fixed in such a manner that a part of the ball joint is sandwiched between the insertion hole, the slit communicating with the insertion hole, and the clamp part divided by the slit. A ball joint including a spherical ball portion, and a ball stud provided with a stud portion protruding from the ball portion and inserted into the insertion hole and sandwiched and fixed by the clamp portion; and the ball portion. A housing that is rotatably received, and a dust cover that is formed of an elastic member and covers the space between the ball stud and the housing. The dust cover is formed in a cylindrical shape between the axial ends. A dust cover body having a bent portion at at least one location, and one end side in the axial direction of the dust cover body. A first lip that is pressed against a member and that tightens the outer surface of the stud portion; and a second lip that is provided on the other end side in the axial direction of the dust cover body and tightens the outer surface of the housing. The tightening force for tightening the stud portion is larger than the tightening force for tightening the housing of the second lip.

  A ball joint according to a second aspect is the ball joint according to the first aspect, wherein the outer surface of the ball stud and the first lip are provided with concave and convex shapes that fit together.

  A ball joint according to a third aspect is the ball joint according to the first or second aspect, wherein at least one of the outer surface of the housing and the second lip is provided with a recess at a position facing the other.

  The ball joint according to claim 4 is the ball joint according to any one of claims 1 to 3, wherein the ball joint is interposed between the second lip of the dust cover and the housing to reduce sliding resistance between the second lip and the housing. A low sliding member is provided.

  A ball joint according to a fifth aspect is the ball joint according to any one of the first to third aspects, wherein at least one of the second lip of the dust cover and the position where the second lip of the housing contacts the second lip. 2 A low-sliding process that reduces the sliding resistance between the lip and the housing is applied.

  According to the ball joint of the first aspect, the bent portion is provided at least at one position between both ends in the axial direction of the cylindrical dust cover main body of the dust cover, and the first is provided on one end side in the axial direction of the dust cover main body. The tightening force for tightening the stud portion of one lip is set larger than the tightening force for tightening the housing of the second lip provided on the other end side in the axial direction of the dust cover body, so that the first stud is swung. The lip is made to follow the stud part reliably and the sliding contact with the mating member is suppressed, so that the wear of the dust cover due to the contact with the mating member can be suppressed and the force generated when the dust cover is deformed due to the swing of the ball stud is bent. It is possible to prevent the second lip from coming off from the housing by concentrating on the portion, and to ensure sealing performance.

  According to the ball joint of the second aspect, in addition to the effect of the ball joint of the first aspect, the outer surface of the ball stud and the first surface of the ball stud are provided with an uneven shape that fits to each other. The contact area with one lip can be increased, and the tightening force for tightening the stud portion of the first lip can be more reliably increased.

  According to the ball joint according to claim 3, in addition to the effect of the ball joint according to claim 1 or 2, by providing a recess at a position facing the other of at least one of the outer surface of the housing and the second lip. The contact area between the outer surface of the housing and the second lip can be reduced to reduce the sliding resistance, and the tightening force for tightening the housing of the second lip can be more reliably reduced.

  According to the ball joint of the fourth aspect, in addition to the effect of the ball joint according to any one of the first to third aspects, the sliding between the second lip and the housing is provided between the second lip of the dust cover and the housing. By interposing a low-sliding member that lowers the dynamic resistance, it is possible to more reliably reduce the tightening force for tightening the housing of the second lip.

  According to the ball joint of the fifth aspect, in addition to the effect of the ball joint according to any one of the first to third aspects, at least one of the second lip of the dust cover and the position where the second lip of the housing abuts. Furthermore, by applying a low sliding process that reduces the sliding resistance between the second lip and the housing, the tightening force for tightening the housing of the second lip can be more reliably reduced.

BRIEF DESCRIPTION OF THE DRAWINGS The ball joint of the 1st Embodiment of this invention is shown, (a) is a longitudinal cross-sectional view of a ball joint, (b) is a top view of a ball joint. It is sectional drawing which expands and shows a part of dust cover of a ball joint same as the above, (a) shows the state of one side when a ball stud rocks, (b) shows when a ball stud rocks The state on the other side is shown. It is sectional drawing which expands and shows a part of ball joint of the 2nd Embodiment of this invention. It is sectional drawing which expands and shows a part of ball joint of the 3rd Embodiment of this invention. It is sectional drawing which shows the dust cover of the ball joint of the 4th Embodiment of this invention.

  The configuration of the first embodiment of the present invention will be described below with reference to FIGS.

  In FIGS. 1 (a) and 1 (b), 11 is a ball joint, and this ball joint 11 is used for a suspension device of a vehicle such as an automobile. The ball joint 11 is configured to connect a lower arm (not shown) and a knuckle 12 which is a counterpart member.

  Here, the knuckle 12 has a circular insertion hole 14, a slit 15 that communicates with the insertion hole 14 and continues to the tip of the knuckle 12, and a pair of clamps divided by the slit 15 (a pair). 16 and 16. In addition, the clamp portions 16 and 16 have a circular through-hole at a position that overlaps a part of the insertion hole 14 in a direction intersecting (orthogonal) with the insertion hole 14, that is, along the axial direction of the insertion hole 14. Holes 17 and 17 are provided, and bolts (pinch bolts) 18 that are fastening members are inserted into the through holes 17 and 17, and a nut 19 is screwed to the tip side of the bolt 18. The clamp portions 16 and 16 are open on the side facing the slit 15. The knuckle 12 is clamped by bolts 18 so that the clamp portions 16 and 16 are brought close to each other, so that a part of the ball joint 11 is sandwiched and fixed.

  On the other hand, the ball joint 11 includes a ball stud 21 that is a ball side member, a ball sheet 22 that is a bearing seat that holds a part of the ball stud 21, and a receiver that holds the ball sheet 22 together with a part of the ball stud 21. A housing 23 that is a side member and a dust cover 24 that is a dust-proof member disposed between the ball stud 21 and the housing 23 are provided. The vertical direction shown below is a direction along the axial direction of the ball joint 11 in a normal state where no load is applied, and the ball stud 21 side is the upper side and the housing 23 side is the lower side.

  The ball stud 21 is made of, for example, a metal such as steel. The ball portion 31 is a substantially spherical sphere head, and the ball stud 21 protrudes from the ball portion 31 and is inserted into the insertion hole 14 of the knuckle 12 from below to above. And a stud portion 32 which is a shaft portion having a round shaft shape (substantially cylindrical shape) which is vertically long.

  The stud portion 32 is formed with a groove portion 34 with which the bolt 18 is engaged on the outer surface on the tip (upper end) side, that is, the outer peripheral surface. Further, on the outer peripheral surface of the stud portion 32, a stud having a predetermined width along the axial direction of the stud portion 32 (stud) is provided at a position facing the upper end side of the dust cover 24 on the base end side (lower end side) with respect to the groove portion 34. (Side side) An uneven shape 35 is formed.

  The groove 34 is formed on the outer peripheral surface of the stud portion 32 at a position where it is inserted into the insertion hole 14 of the knuckle 12. The groove portion 34 is formed in an arc shape in cross section, and a part of the outer peripheral surface of the bolt 18 inserted through the through holes 17, 17 is fitted therein.

  The uneven shape 35 is located on the outer peripheral surface of the stud portion 32 located below the insertion hole 14 of the knuckle 12. The concave / convex shape 35 is formed by alternately forming a concave groove portion (concave portion) and a stud portion (protruding portion) along the circumferential direction of the stud portion 32 in the axial direction of the stud portion 32. Or a plurality of grooves or protrusions are intermittently formed in the axial direction of the stud portion 32 along the circumferential direction of the stud portion 32. In the present embodiment, the concavo-convex shape 35 is formed by alternately forming a plurality of concave grooves and protrusions having a triangular cross section or an arc shape in the axial direction of the stud portion 32.

  The ball seat 22 is formed of, for example, a synthetic resin and has a cylindrical shape with openings 37 and 38 at both ends in the vertical direction. The inner surface of the ball sheet 22 is a spherical holding surface (sliding surface) 39 continuous with the openings 37 and 38, and the holding surface 39 rotatably holds the outer peripheral surface of the ball portion 31. ing. In addition, fluid grease, which is a lubricant (not shown), is interposed between the holding surface 39 (ball seat 22) and the outer peripheral surface of the ball portion 31.

  The housing 23 is also called a socket, and is integrally formed of, for example, aluminum and has a substantially cylindrical shape. That is, the housing 23 has a cylindrical shape having openings 41 and 42 at both ends in the vertical direction. A mounting recess 43 into which the lower end side of the dust cover 24 is fitted is formed in the outer surface of the housing 23, that is, the outer peripheral surface, in a groove shape continuous in the circumferential direction. Further, inside the housing 23, the ball portion 31 is received (held) through the ball seat 22 in communication with the openings 41, 42, in other words, the ball seat 22 holding the ball portion 31 is fitted. An inner chamber 44 as a receiving portion is formed. Accordingly, the openings 41 and 42 are in communication with the openings 37 and 38 of the ball seat 22 held in the inner chamber 44, and the opening 41 on the upper end side is inserted into the opening 37 on the upper end side of the ball seat 22. The stud portion 32 of the ball stud 21 is inserted. Furthermore, the opening 42 on the lower end side of the housing 23 is closed by a plug 45 that is a closing member. The plug 45 is formed in a circular plate shape, and the outer peripheral edge portion of the plug 45 is formed with respect to the housing 23 by a caulking portion 46 in which the edge portion of the opening portion 42 of the housing 23 is caulked and deformed inward (center axis side). Is fixed. The housing 23 is formed integrally with the lower arm (not shown).

  The mounting recess 43 rises vertically from the inner peripheral side of the end-side lip surface portion 43a to receive the lower end side of the dust cover 24 in the axial direction, and rises vertically from the inner peripheral side of the end-side lip surface portion 43a. The inner circumferential side lip surface portion 43b that receives the inner circumferential side in the radial direction is formed in a substantially L-shaped cross section. A plurality of recesses 48 are formed in the inner peripheral lip surface portion 43b so as to be spaced apart from each other in the axial direction of the housing 23, and these recesses 48 reduce the contact area with the dust cover 24 to reduce the sliding resistance ( To improve the slidability).

  The dust cover 24 is also called a dust seal or a boot, and is entirely formed of an elastic member such as soft rubber or soft synthetic resin, for example. The dust cover 24 includes a substantially cylindrical dust cover main body 51, a first lip (upper end lip) 52 positioned at the upper end that is one end of the dust cover main body 51, and a lower end that is the other end of the dust cover main body 51. And a second lip (lower end lip) 53 located at the same position.

  In the present embodiment, the dust cover main body 51 has an axial dimension, that is, a vertical dimension that is smaller than a radial dimension, that is, a flat shape in the axial direction. Further, the dust cover main body 51 is formed such that the upper end side has a smaller diameter than the lower end side. Further, the dust cover main body 51 bulges from the upper and lower ends to the intermediate portion in the axial direction so that the diameter dimension gradually increases. Therefore, an intermediate portion between both ends of the dust cover main body 51 is a bent portion 55 that protrudes (bulges) in the radial direction from the other portions of the dust cover main body 51. The bent portion 55 is curved in a curved surface shape.

  The first lip 52 is formed to have a smaller diameter than the second lip 53, and an end surface 52a which is the upper end surface is pressed against the lower portion of the clamp portions 16 and 16 of the knuckle 12 from below to above, The peripheral surface 52b is a portion that tightens the outer peripheral surface of the stud portion 32 toward the central axis side of the stud portion 32 (dust cover 24). That is, the inner peripheral surface 52 b of the first lip 52 faces the uneven shape 35 of the stud portion 32. Further, an annular (first) fastening member 56 such as a metal wire for fastening the outer peripheral surface of the stud portion 32 is embedded in the first lip 52. Further, the inner peripheral surface 52b of the first lip 52 is formed with an uneven shape 57 that fits with the uneven shape 35 of the stud portion 32 (on the dust cover side). In other words, the concave and convex shape 57 has protrusions (convex portions) and (dust cover side) concave grooves (concave portions) alternately formed in the axial direction of the dust cover 24 along the circumferential direction of the dust cover 24. Or a plurality of protrusions and concave grooves are intermittently formed in the axial direction of the dust cover 24 along the circumferential direction of the dust cover 24. In the present embodiment, the concavo-convex shape 57 is formed by alternately forming a plurality of triangular and arcuate projections and recesses in the axial direction of the dust cover 24 that fit into the recesses and projections of the concavo-convex shape 35, respectively. Has been configured. Therefore, the concave and convex shapes 57 and 35 improve the contact area between the dust cover 24 and the stud portion 32 and increase the sliding resistance (decrease the sliding property).

  The second lip 53 is an end lip surface in which an end surface 53a which is a lower end surface is pressed from the upper side to the lower side lip surface portion 43a of the mounting recess 43 of the housing 23, and an inner peripheral surface 53b is The inner lip surface 43b of the mounting recess 43 of the housing 23 is a shaft lip surface that is tightened toward the central axis of the housing 23 (dust cover 24). That is, the inner peripheral surface 53 b of the second lip 53 is opposed to the inner peripheral lip surface portion 43 b of the mounting recess 43 on the outer peripheral surface of the housing 23. Further, an annular (second) fastening member such as a metal wire for fastening the outer peripheral surface (inner peripheral side lip surface portion 43b) of the housing 23 (mounting recess 43) is provided inside the second lip 53. 59 is embedded.

  The first and second lips 52 and 53 are different from each other in the tightening force F1 and F2 for tightening the stud portion 32 and the housing 23, and the first and second lips 52 and 53 are different from each other. Is set larger than. As a result, the first lip 52 is fixed so as not to slide (rotate) in the circumferential direction with respect to the outer peripheral surface of the stud portion 32, and the second lip 53 is fixed to the outer peripheral surface of the housing 23 (the mounting recess 43 (inner It is slidable in the circumferential direction relative to the circumferential lip surface portion 43b)). The tightening force F2 of the second lip 53 is set within a range in which the sealing performance with the housing 23 can be maintained.

  Next, the operation of the first embodiment will be described.

  In the assembled ball joint 11, the stud portion 32 of the ball stud 21 is inserted from below into the insertion hole 14 of the knuckle 12, and the end surface 52a of the first lip 52 of the dust cover 24 is inserted into the knuckle 12 (clamp portions 16, 16). The groove 34 is aligned with the through-holes 17 and 17 in a state in which the slit 15 is pressed against the lower portion of the screw, and the bolt 18 is inserted into the through-holes 17 and 17 and the nut 19 is screwed and tightened so that the slit 15 is narrowed. Then, the clamp portions 16 and 16 are brought close to each other in the axial direction of the ball stud 21 (stud portion 32) to sandwich the stud portion 32, and the ball joint 11 is connected and fixed.

  When the knuckle 12 rotates due to vibration generated in the vehicle, the ball stud 21 integrally fixed to the knuckle 12 follows and swings. At this time, in the dust cover 24, the first lip 52 is fixed to the outer peripheral surface of the stud portion 32, so that the end surface 52a of the first lip 52 basically has the knuckle 12 (the clamp portions 16 and 16). The close contact state is maintained, and the knuckle 12 (clamp portions 16, 16) is not slidably contacted.

  When the ball stud 21 swings, the dust cover 24 is deformed as shown in FIGS. 2A and 2B, so that the first lip 52 and the second lip 53 are Pulling forces F3 and F4 and pressing forces F5 and F6 are applied. At this time, the first lip 52 has a sufficiently large tightening force F1 and is fixed to the stud portion 32, so that there is no displacement with respect to the pulling force F3 and the pressing force F5, and the sealing performance. Is secured. On the other hand, the second lip 53 has a relatively small tension force F2, but the bending portion 55 extends against the pulling force F4, so that a reaction force acts on the pulling force F4 to reduce the pulling force F4. For the pressing force F6, the bending portion 55 bends to absorb the pressing force F6 and reduce the pressing force F6. Therefore, the pressing force F6 is removed from the housing 23 (mounting recess 43) or the end side of the mounting recess 43. The end surface 53a and the inner peripheral surface 53b are not separated from the lip surface portion 43a and the inner peripheral lip surface portion 43b, and sealing performance is ensured.

  As described above, according to the first embodiment, the bent portion 55 is provided at least at one position between both ends in the axial direction of the cylindrical dust cover main body 51 of the dust cover 24, and the dust cover main body 51 The tightening force F1 for tightening the stud portion 32 of the first lip 52 provided on one end side in the axial direction is more than the tightening force F2 for tightening the housing 23 of the second lip 53 provided on the other end side of the dust cover body 51 in the axial direction. When the ball stud 21 swings, the knuckle 12 (the lower part facing the slit 15 of the clamp parts 16, 16 (the dust cover 24 side) The sliding contact with the edge of the ball stud 21 can be suppressed (prevented), the wear of the dust cover 24 (first lip 52) due to contact with the knuckle 12 can be suppressed, and the dust cover 24 can be deformed when the ball stud 21 swings. The resulting force (tensile force and push Force) is concentrated to the bending portion 55, even if small straining force F2 of the second lip 53 can be prevented from coming off from the housing 23 of the second lip 53 can ensure the sealing property.

  That is, the first lip 52 side is fixed to the stud portion 32 and does not slide with the knuckle 12 that moves integrally with the ball stud 21 when the ball stud 21 swings. By making the side slidable with respect to the housing 23, the dust cover 24 is not twisted when the ball stud 21 swings.

  Further, by providing the outer surface of the ball stud 21 and the concavo-convex shapes 35 and 57 which are fitted to the first lip 52, the contact area between the outer surface of the ball stud 21 and the first lip 52 is increased. The tightening force F1 for tightening the stud portion 32 can be increased more reliably, and the tightening force F1 of the first lip 52 can be easily and reliably increased than the tightening force F2 of the second lip 53.

  Furthermore, the contact area between the outer surface of the housing 23 and the second lip 53 is reduced by providing a recess 48 at a position facing the outer surface of the housing 23 and at least one of the second lips 53 to form a labyrinth. Thus, the sliding resistance can be reduced, and the tightening force F2 for tightening the housing 23 of the second lip 53 can be more reliably reduced.

  Further, since the wear and scratches of the first lip 52 of the dust cover 24 can be suppressed, it is possible to suppress the deterioration of the sealing performance at the end face 52a of the first lip 52 due to the wear and scratches. It is possible to reliably suppress abnormal wear due to inundation or rusting that occurs, or deterioration of the sealing performance due to the immersion of the water to the second lip 53, and further infiltration due to the deterioration of the sealing performance. Can be suppressed, and better performance stable over a long period of time can be maintained.

  In the first embodiment, for example, as in the second embodiment shown in FIG. 3, instead of the recess 48, for example, a low-sliding member such as an annular formed of synthetic resin or metal. 61 may be interposed between the housing 23 (mounting recess 43 (inner peripheral lip surface 43b)) and the second lip 53 of the dust cover 24. By reducing the sliding resistance of the second lip 53 with the low sliding member 61 in this way, the tension force F2 of the second lip 53 can be more reliably reduced, and the tension force F2 of the second lip 53 can be reduced. The tension force F1 of the first lip 52 can be easily and reliably reduced.

  Similarly, for example, as in the third embodiment shown in FIG. 4, instead of the recess 48, at least one of the inner peripheral lip surface portion 43b of the mounting recess 43 and the second lip 53 (in this embodiment) A low sliding process 63 may be applied to the inner peripheral lip surface portion 43b). The low-sliding process 63 is configured by, for example, applying a DLC (Diamond-Like Carbon) film or a coating material (coating). Further, by reducing the sliding resistance of the second lip 53 by the low sliding process 63 as described above, the tightening force F2 of the second lip 53 can be more reliably decreased, and the tightening force of the second lip 53 is reduced. F2 can be easily and reliably made smaller than the tightening force F1 of the first lip 52.

  Further, in each of the above embodiments, as in the fourth embodiment shown in FIG. 5, the dust cover 24 is gradually expanded in diameter from the upper end to the lower end, and has a plurality of bent portions 55 between both ends. Even if it is formed in a bellows shape, the same effect can be obtained.

  In each of the above embodiments, for example, the first lip 52 is fixed from the outer peripheral side with an annular clip or the like in order to make the urging force F1 of the first lip 52 larger than the urging force F2 of the second lip 53. The diameter of the inner periphery of the first lip 52 may be relatively decreased to increase the tightening allowance. For example, the diameter of the inner periphery of the second lip 53 may be relatively increased to tighten. You may reduce the bill.

  Further, in order to more reliably prevent the second lip 53 from dropping from the mounting recess 43 due to the swing of the ball stud 21, the area of the end surface 53a and the inner peripheral surface 53b of the second lip 53 and the mounting recess of the housing 23 are prevented. The area of the end lip surface portion 43a and the inner peripheral lip surface portion 43b of 43 is enlarged so that the housing 23 and the second lip 53 have an amount that exceeds the amount of movement of the second lip 53 due to the swing of the ball stud 21. You may comprise so that a contact range may be ensured.

  Furthermore, the ball joint 11 can be used, for example, for a tie rod end of a vehicle steering apparatus, and can be configured to connect the stud portion 32 of the ball stud 21 to a steering knuckle that is a counterpart member.

  The ball joint 11 can also be used in any device other than the vehicle.

  The present invention can be suitably used for a suspension device of a vehicle such as an automobile.

11 Ball joint
12 Knuckle that is the mating member
14 Insertion hole
15 slit
16 Clamp part
21 Ball stud
23 Housing
24 Dust cover
31 Ball
32 Stud section
35, 57 Uneven shape
48 Recess
51 Dust cover body
52 1st lip
53 2nd lip
55 Bend
61 Low sliding member
63 Low sliding processing
F1, F2 Tension

Claims (5)

A ball joint that is partly sandwiched and fixed by an insertion hole, a slit communicating with the insertion hole, and a counterpart member having a clamp part divided by the slit,
A ball stud provided with a spherical ball portion, and a stud portion protruding from the ball portion and inserted into the insertion hole and sandwiched and fixed by the clamp portion;
A housing for receiving the ball portion in a rotatable manner;
A dust cover formed by a member having elasticity, and covering between the ball stud and the housing;
The dust cover is
A dust cover body which is formed in a cylindrical shape and has a bent portion at least at one place between both ends in the axial direction;
A first lip that is provided on one end side in the axial direction of the dust cover body, is pressed against the mating member and tightens the outer surface of the stud portion;
A second lip provided on the other end side in the axial direction of the dust cover main body and tightening an outer surface of the housing;
The ball joint according to claim 1, wherein a tightening force for tightening the stud portion of the first lip is larger than a tightening force for tightening the housing of the second lip. The ball joint according to claim 1, wherein the outer surface of the ball stud and the first lip have an uneven shape that fits with each other. The ball joint according to claim 1, wherein at least one of the outer surface of the housing and the second lip is provided with a recess at a position facing the other. The low-sliding member interposed between the second lip of the dust cover and the housing and reducing sliding resistance between the second lip and the housing is provided. Ball joint. A low-sliding process for reducing the sliding resistance between the second lip and the housing is applied to at least one of the second lip of the dust cover and the position of the housing in contact with the second lip. The ball joint according to any one of claims 1 to 3.

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