JP5252198B2 - Ball joint - Google Patents

Description

  The present invention relates to a ball joint.

  In general, a ball joint has a spherical head provided at one end of a ball stud and a resin sheet covering the spherical head. One end of the housing is sealed and the other end is used as an inlet for the resin sheet and the spherical head. It is configured to be accommodated in a cylindrical accommodation chamber. The resin sheet is usually formed in one piece in a cup shape in which one end of a cylindrical peripheral wall portion is provided with a bottom portion facing the bottom of the storage chamber, and the opposite side is opened.

For example, an inner ball joint or the like of a steering device for an automobile should have a smaller diameter than other parts by caulking the inlet with the resin sheet and the ball head housed in a housing chamber and filled with a lubricant such as grease. The ball head is prevented from slipping off and the resin sheet is pressurized.
At the bottom of the resin sheet, a through-hole is formed for accelerating deformation and alleviating the impact when force is applied from the ball head. The through-hole also functions to store a lubricant.

On the inner surface of the resin sheet, in order to supply the lubricant to almost the entire surface of the ball head from the through hole, a concave groove extending mainly in a direction parallel to the central axis of the cylinder and reaching the opening or the vicinity thereof is provided. (Patent Documents 1 and 2).
Japanese Utility Model Publication No. 61-84221 JP-A-8-326739

  However, in the conventional ball joint, when the resin sheet is accommodated in the accommodating chamber together with the ball head and the inlet of the accommodating chamber is caulked to have a smaller diameter than other portions, the opening side of the resin sheet is caulked. Since the compression deformation is mainly performed in the thickness direction so as to fill a gap between the inner surface of the storage chamber and the surface of the spherical head, the groove on the opening side becomes extremely shallow due to the compression deformation. Or, it tends to be completely crushed and lost. Therefore, there is a problem that the lubricant cannot be sufficiently supplied through the groove to the region on the opening side of the resin sheet, and the resin sheet is easily worn in a short period due to insufficient supply of the lubricant.

  An object of the present invention is to provide a ball joint capable of suppressing wear of a resin sheet over a long period of time because it is difficult to cause insufficient supply of a lubricant.

To achieve the above object, the present invention accommodates a ball stud (18) having a ball head (23) at one end, a resin sheet (17) covering the ball head, the resin sheet and the ball head. A housing (16) having a small diameter by caulking after accommodating a spherical head covered with a resin sheet. The resin sheet has a cylindrical portion (21) that surrounds the spherical head, and a bottom portion (22) that closes one end of the cylindrical portion and faces the bottom of the storage chamber, and is open at the other end of the cylindrical portion. A plurality of concave grooves (52) reaching the opening (50) from the bottom side are provided on the inner surface of the resin sheet, and the depth of each concave groove is on the opening side. bottom side is deeper than, the resin sheet is accommodated in the accommodating chamber The depth of the concave groove is substantially constant from the bottom side to the opening in a state where the inlet is caulked and elastically deformed and pressurized so as to fill a gap between the storage chamber and the ball head. there is provided a ball joint (12), characterized in that it is (claim 1). The alphanumeric characters in parentheses represent corresponding components in the embodiments described later.

According to the present invention, when the resin sheet is accommodated in the accommodation chamber together with the ball head, and the entrance of the accommodation chamber is caulked to have a smaller diameter than other portions, the opening side of the resin sheet is the same as in the conventional case. It is compressed and deformed so as to fill a gap between the inner surface of the crimped storage chamber and the surface of the ball head. However, since the depth of the concave groove is set deeper than the bottom side on the opening side of the resin sheet as described above, the concave groove becomes extremely shallow on the opening side or completely crushed even after compressive deformation. The depth can be maintained substantially constant , suitable for the supply of lubricant, without being lost. Therefore, according to the present invention, a sufficient amount of lubricant can be supplied over almost the entire surface of the ball head through the concave groove, and the supply of lubricant is unlikely to occur. It is possible to provide a ball joint that can suppress the above for a long time.

According to the present invention, the depth of each of the concave grooves can be gradually increased in the cylindrical portion from the bottom side toward the opening side (Claim 2).
In this case, it is easy to process the region corresponding to the concave groove of the injection mold that is the basis of the resin sheet, injection molding using the injection mold, die cutting after injection molding, etc. .

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a schematic diagram illustrating a schematic configuration of a steering apparatus 1 including a ball joint according to an embodiment of the present invention. The steering device 1 includes a steering wheel 2 as a steering member and a rack and pinion mechanism 3 as a turning mechanism for turning steered wheels (not shown).

The steering wheel 2 is connected to the rack and pinion mechanism 3 via a steering shaft 4 and an intermediate shaft 5. The rotation of the steering wheel 2 is transmitted to the rack and pinion mechanism 3 via the steering shaft 4 and the intermediate shaft 5.
The rack and pinion mechanism 3 includes a pinion shaft 6 and a rack shaft 7. The pinion shaft 6 includes a shaft portion 8 connected to the intermediate shaft 5 and a pinion 9 connected to the tip of the shaft portion 8. The rotation of the steering wheel 2 is transmitted to the pinion shaft 6 via the steering shaft 4 and the intermediate shaft 5.

The rack shaft 7 extends along the left-right direction of the vehicle. A rack 10 is formed on the rack shaft 7. The pinion 9 and the rack 10 are meshed with each other. The rotation of the pinion shaft 6 is converted into an axial movement of the rack shaft 7 by the rack 10 and the pinion 9.
The rack shaft 7 is inserted into a cylindrical housing 11. Both end portions of the rack shaft 7 protrude from the housing 11. One end of a tie rod 14 is connected to each end of the rack shaft 7 via an inner ball joint 12. An outer ball joint 13 is provided at the other end of the tie rod 14 (so-called tie rod end). Although not shown, the steered wheels are connected to the outer ball joint 13 via a knuckle arm.

  A cylindrical rack boot 15 is disposed at each end of the housing 11. One end of each rack boot 15 is fitted around the end of the housing 11 and is fixed to the end. Further, the other end of each rack boot 15 is externally fitted to the tie rod 14 and is fixed to the tie rod 14. The end of the housing 11 and the inner ball joint 12 are covered with a corresponding rack boot 15. The rack boot 15 prevents foreign matters such as water and dust from entering the housing 11 and the inner ball joint 12.

  In the steering operation (rotation operation), as described above, the rotation of the steering wheel 2 is transmitted to the pinion shaft 6 by the steering shaft 4 and the intermediate shaft 5, and the rotation of the pinion 9 is moved in the axial direction of the rack shaft 7 through the rack 10. Converted. The axial movement of the rack shaft 7 at that time is transmitted to the tie rod 14 via the inner ball joint 12, and the movement of the tie rod 14 is further transmitted to the knuckle arm via the outer ball joint 13.

FIG. 2 is a cross-sectional view of a part of the steering device 1 including the inner ball joint 12 and the outer ball joint 13.
The inner ball joint 12 includes a housing 16 connected to an end of the rack shaft 7 (see FIG. 1), and a resin sheet 17 and a ball stud 18 held by the housing 16. The housing 16 includes a storage chamber 19 that stores the resin sheet 17 and the ball stud 18, and a connecting portion 20 that is connected to the end of the rack shaft 7. The storage chamber 19 has a cylindrical shape with a sealed bottom and has an inlet. The resin sheet 17 has a cup shape and includes a cylindrical portion 21 and a bottom portion 22. The resin sheet 17 is disposed so that the bottom portion 22 faces the bottom of the storage chamber 19.

  The ball stud 18 is integrally provided with a spherical head 23 having a spherical outer surface and a rod 24 extending so as to protrude from the spherical head 23. The spherical head 23 is covered with the resin sheet 17, and the rod 24 protrudes from the storage chamber 19. The entrance of the storage chamber 19 is caulked after receiving the ball head 23 covered with the resin sheet 17 to have a small diameter so that the ball head 23 and the resin sheet 17 are prevented from coming off.

A part of the tie rod 14 is constituted by a ball stud 18. That is, the tie rod 14 includes a ball stud 18 and a connecting shaft 25 connected to the rod 24 of the ball stud 18.
A male screw portion 26 is formed at the tip portion (right end portion in FIG. 2) of the rod 24. The male screw portion 26 is screwed into a female screw hole 27 formed in the connecting shaft 25. The male screw portion 26 is screwed into the female screw hole 27, whereby the connecting shaft 25 is coaxially connected to the ball stud 18.

  A lock nut 28 is screwed into the male screw portion 26. The ball stud 18 and the connecting shaft 25 are fixed to each other by a lock nut 28. Further, the screwing amount of the male screw portion 26 with respect to the female screw hole 27 is adjusted by a lock nut 28. The toe angle of the steered wheel can be adjusted by adjusting the screwing amount of the male screw portion 26 into the female screw hole 27.

  The ball head 23 is held so as to be wrapped in the storage chamber 19 via the resin sheet 17. The inner peripheral surface of the resin sheet 17 has a shape along the outer surface of the ball head 23. The ball head 23 is slidable with respect to the resin sheet 17. A lubricant such as grease is filled between the resin sheet 17 and the ball head 23. The ball stud 18 can swing with respect to the housing 16 with the ball head 23 as a fulcrum. Therefore, the movement of the rack shaft 7 (see FIG. 1) in the axial direction is not transmitted linearly to the tie rod 14 in the axial direction, but is transmitted in the angular direction where the inner ball joint 12 swings.

  On the other hand, the outer ball joint 13 includes a housing 29 and a resin sheet 30 and a ball stud 31 held by the housing 29. The housing 29 includes a cylindrical member 32 in which the resin sheet 30 is disposed, and a closing plate 33 fixed to the one end so as to close one end (the lower end in FIG. 2) of the cylindrical member 32. The cylindrical member 32 is integrally formed at the distal end portion of the connecting shaft 25, for example.

  The resin sheet 30 includes a cup-shaped first sheet 34 and a plate-shaped second sheet 35. The first sheet 34 is integrally provided with a peripheral wall portion 36 and a bottom portion 37. The first sheet 34 is disposed such that the peripheral wall portion 36 is along the inner peripheral surface of the cylindrical member 32. The second sheet 35 is interposed between the bottom 37 of the first sheet 34 and the closing plate 33. The resin sheet 30 is held between an annular flange 38 projecting inward from the other end (upper end in FIG. 2) of the cylindrical member 32 and the closing plate 33.

  The ball stud 31 is integrally provided with a spherical head 39 having a spherical outer surface and a rod 40 protruding upward from the spherical head 39. The spherical head 39 is covered with the first sheet 34, and the rod 40 protrudes from the cylindrical member 32. The spherical head 39 is held by the housing 29 via the first sheet 34. That is, the ball stud 31 is held by the housing 29 via the first sheet 34.

  The inner peripheral surface of the first sheet 34 is shaped along the outer surface of the ball head 39. The spherical head 39 is slidable with respect to the resin sheet 30. A lubricant is filled between the first sheet 34 and the ball head 39. The ball stud 31 can swing with respect to the housing 29 with the ball head 39 as a fulcrum. Further, the ball stud 31 is rotatable around the central axis of the rod 40. The outer ball joint 13 transmits the movement of the tie rod 14 to the knuckle arm in the swinging angular direction.

  A cylindrical cover 41 is attached to the housing 29 and the ball stud 31. One end of the cover 41 is fitted around the end of the cylindrical member 32 and is fixed to the end. The other end of the cover 41 is externally fitted to the rod 40 and is fixed to the rod 40. An end of the cylindrical member 32 and a part of the rod 40 are covered with a cover 41. The cover 41 prevents foreign matters such as water and dust from entering the outer ball joint 13.

Next, a specific configuration of the ball joint according to this embodiment will be described by taking the inner ball joint 12 as an example.
FIG. 3 is a partial cross-sectional view showing a schematic configuration of the inner ball joint 12 according to the embodiment of the present invention. FIG. 4 is a partial cross-sectional view showing a state in which the inner ball joint 12 is being assembled. FIG. 5 is a cross-sectional view showing an example of the resin sheet 17 incorporated in the inner ball joint 12.

With reference to FIG. 3, the inner ball joint 12 includes a ball stud 18, a housing 16, and a resin sheet 17. The ball stud 18 is an integrally molded product using a single member made of metal such as steel, and includes a ball head 23 and a rod 24. The center C of the spherical head 23 is disposed on the central axis L1 of the rod 24.
The housing 16 accommodates the ball head 23 and supports the ball stud 18 via the resin sheet 17 so as to be swingable with the ball head 23 as a fulcrum. The housing 16 is an integrally molded product using a single member made of metal such as steel, and includes a storage chamber 19 and a connecting portion 20 (see FIG. 2). The storage chamber 19 includes a cylindrical peripheral wall 42 that surrounds the spherical head 23, and a bottom wall 43 that is connected to one end of the peripheral wall 42 in the axial direction and seals one end of the cylinder to form the bottom.

  The bottom of the storage chamber 19 has a tapered shape in which the opening diameter increases from one side surface (inner bottom surface) 45 of the bottom wall 43 to the other end (front end) side of the peripheral wall 42 from the inner bottom surface 45 side. And the tapered surface 46 is connected to the inner bottom surface 45 and the inner peripheral surface 44 of the cylinder of the peripheral wall 42, and the inner bottom surface 45, the tapered surface 46 and the inner peripheral surface 44 allow the spherical head 23 and the resin sheet 17. A storage space 47 for storing the space is defined. The inner peripheral surface 44 and the tapered surface 46 are opposed to the surface of the spherical head 23. A connecting portion 20 (see FIG. 2) is integrally formed on the bottom wall 43.

  An opening 48 is formed at the other end (tip) of the peripheral wall 42, and the spherical head 23 is accommodated in the accommodation space 47 through the opening 48. The rod 24 is inserted through the opening 48. The peripheral portion 49 of the opening 48 of the peripheral wall 42 has a smaller diameter than the other portions of the peripheral wall 42, and the ball head 23 and the resin sheet 17 are prevented from coming out of the storage chamber 19. 3 and 4, this peripheral portion 49 has a small diameter by caulking (plastically deforming) the other end (tip) of the peripheral wall 42 on the side of the opening 48 of the peripheral wall 42 having a substantially constant outer diameter. It is said that.

  Referring to FIGS. 3 to 5, the resin sheet 17 has a cylindrical portion 21 whose outer periphery is along the inner peripheral surface 44 of the storage chamber 19 and surrounds the spherical head 23, and the cylindrical portion 21. One end is formed in a cup shape with the other end of the cylindrical portion 21 being an opening 50 through which the rod 24 is inserted. The bottom portion 22 is formed in a tapered shape along the tapered surface 46 in the bottom of the storage chamber 19.

A through hole 51 is formed at the center of the bottom 22. The through hole 51 is formed concentrically with the central axis L <b> 2 of the resin sheet 17. By providing the through-hole 51, when a force acts on the resin sheet 17 from the ball head 23, the deformation can be promoted to reduce the impact. The through hole 51 is filled with a lubricant.
4 and 5, a plurality of concave grooves 52 reaching the openings 50 from the through holes 51 are provided on the inner surface of the resin sheet 17. The depth of each concave groove 52 is deeper on the opening 50 side than on the bottom 22 side.

  For example, in the example shown in the drawing, the depth of each concave groove 52 gradually increases in the cylinder portion 21 from the bottom 22 side toward the opening 50 side, and the depth D1 in the opening 50 is the bottom 22 side of the cylinder portion 21. It is deeper than the depth D2 at the end (D1> D2). In such a configuration, processing of the region corresponding to the concave groove 52 of the injection mold that is the basis of the resin sheet 17, injection molding using the injection mold, die cutting after injection molding, etc. Both have the advantage of being easy.

The depth of the concave groove 52 in the bottom 22 is constant up to the through hole 51. 4 and 5 show only two grooves 52, they are provided at a plurality of circumferential positions (for example, six, eight, etc.) of the cylindrical portion 21 at equal angular intervals.
With reference to FIGS. 3 and 4, the other end (tip) of the peripheral wall 42 on the side of the opening 48 is caulked while the resin sheet 17 and the ball head 23 are accommodated in the accommodation space 47 of the accommodation chamber 19. By making 49 a small diameter, the cup-shaped resin sheet 17 is elastically deformed and pressurized so as to fill the gap between the storage chamber 19 and the ball head 23.

With reference to FIG. 3, the inner peripheral surface 53 of the deformed resin sheet 17 is formed in a shape along the surface of the ball head 23, and supports the ball head 23 so as to be slidable. The outer peripheral surface 54 of the resin sheet 17 is formed in a shape along the inner peripheral surface 44 and the tapered surface 46 of the storage chamber 19, and is supported by the inner peripheral surface 44 and the tapered surface 46.
In such a deformed state, the depth of the concave groove 52 is substantially constant from the through hole 51 to the opening 50. This is because the depth on the opening 50 side, which is greatly compressed in the thickness direction, of the concave groove 52 before deformation is set deeper than the bottom portion 22 side as described above. Therefore, a sufficient amount of the lubricating oil stored in the through hole 51 can be supplied to the opening 50 side through the concave groove 52, that is, over almost the entire surface of the ball head 23, and insufficient supply of lubricant is unlikely to occur. Thus, wear of the resin sheet 17 can be suppressed over a long period of time.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims. In the following, differences from the embodiment shown in FIGS. 1 to 5 will be mainly described, and the same components are denoted by the same reference numerals, and description thereof will be omitted.
For example, as shown in FIG. 6, each concave groove 52 has a constant depth D2 of the region 55 on the bottom 22 side of the cylindrical portion 21 and a depth of the region 56 on the opening 50 side of the region 55. However, the depth D1 gradually increases toward the opening 50, and the depth D1 at the opening 50 is deeper than the depth D2 at the bottom 22 side (D1> D2).

  In addition, the ball joint of the present invention can be used for purposes other than the purpose of connecting the rack shaft and the tie rod.

It is a mimetic diagram showing a schematic structure of a steering device provided with a ball joint concerning one embodiment of the present invention. It is a sectional view of a part of a steering device including an inner ball joint and an outer ball joint. It is a partial sectional view showing a schematic structure of an inner ball joint concerning one embodiment of the present invention. It is a partial sectional view showing a state during the assembly of the inner ball joint. It is sectional drawing which shows an example of the resin sheet incorporated in an inner ball joint. It is sectional drawing which shows the modification of a resin sheet.

Explanation of symbols

  12: Ball joint (inner ball joint), 16: Housing, 17: Resin sheet, 18: Ball stud, 21: Tube part, 22: Bottom part, 23: Ball head, 42: Storage chamber, 50: Opening, 52: Ditch

Claims (2)

A ball stud having a ball head at one end;
A resin sheet covering the ball head;
A housing chamber for housing the resin sheet and the ball head, the bottom of the housing chamber is sealed, and the inlet is a caulked housing having a small diameter after housing the ball head covered with the resin sheet. Prepared,
The resin sheet has a cylindrical part surrounding a spherical head and a bottom part that closes one end of the cylindrical part and faces the bottom of the storage chamber, and is formed in a one-piece cup shape with the other end of the cylindrical part opened. ,
A plurality of concave grooves reaching the opening from the bottom side are provided on the inner surface of the resin sheet, and the depth of each concave groove is deeper than the bottom side on the opening side ,
The resin sheet is accommodated in the accommodation chamber, caulked at the inlet, and is elastically deformed and pressurized so as to fill a gap between the accommodation chamber and the ball head. A ball joint characterized in that the length is substantially constant from the bottom side to the opening .   2. The ball joint according to claim 1, wherein the depth of each of the concave grooves is gradually increased from the bottom side toward the opening side in the cylindrical portion.

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