JP2005133871A - Ball joint and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the lubricating property of a ball joint without impairing the durability of a bearing. <P>SOLUTION: In this ball joint comprising a ball stud composed of a prolate part having the elliptic cross-sectional shape, and a handle part extended from the prolate part, the bearing made out of a synthetic resin, oscillatably rotatably holding the prolate part of the ball stud, and having the inner peripheral shape approximately same as an outer peripheral shape of the prolate part, and a housing accommodating the bearing, and having an opening from which the handle part of the ball stud is projected, at its one side, the prolate part of the ball stud is mounted in the bearing in a state that an axial center of the ball stud is inclined to an axial center of the bearing, and a recessed part is formed on an inner peripheral face of the bearing by heating the bearing at its softening temperature. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a ball joint used for, for example, a suspension device and a steering device of an automobile.

  Conventionally, ball joints have been frequently used for connecting parts of automobile suspensions and steering devices. As shown in FIG. 7, such a ball joint 101 includes a ball stud 102 having a spherical ball head 104 and a handle 103 extending from the ball head 104, and a ball head 104 of the ball stud 102. A synthetic resin bearing 105 having a bearing opening 106 at one end and a small opening 110 for encasing the bearing 105 and projecting the handle 103 of the ball stud 102 from the inner periphery thereof. A housing 109 having a large opening 111 on the other side, a closing plate 114 that is caulked and fixed to the end of the large opening 111 of the housing 109, and a dust cover small opening 119 on the outer periphery of the handle 103 of the ball stud 102. And a dust cover 118 for mounting the large opening 120 on the outer periphery of the housing 109.

  The ball head portion 104 of the ball stud 102 has a perfectly circular cross section with the same diameter c extending in the axial direction and the diameter d extending in the horizontal direction. Further, as shown in FIG. 8, the bearing 105 has an inner peripheral surface 107 having substantially the same shape as the outer peripheral surface of the ball head 104, and a plurality of slits 124 extending from the bearing opening 106 side end portion toward the opposite opening side. Was formed.

  A method for manufacturing the ball joint 101 will be described. First, the ball stud 102 in which the bearing 105 is fitted to the ball head 104 is inserted into the large opening 111 of the housing 109 from the handle 103 and the bearing 105 is disposed at a predetermined position in the housing 109. Subsequently, after the closing plate 114 is inserted into the inner periphery of the large opening 110 of the housing 109, the end of the large opening 111 of the housing 109 is crimped to the inner peripheral side. Finally, a dust cover 118 was attached to manufacture the ball joint 101 as shown in FIG.

In the ball joint 101 as described above, a lubricant is applied in the bearing 105 in order to smooth the swing and rotation of the ball head 104, and this lubricant spreads over the entire circumference of the ball head 104. A plurality of slits 124 are formed in the bearing 105. However, the formation of the slit 124 in the bearing 105 results in a reduction in the inner peripheral area of the bearing 105 that abuts the ball head 104 of the ball stud 102, and thus the load applied to the inner peripheral surface 107 of the bearing 105 is large. Therefore, the deformation is promoted, and the ball head 104 of the ball stud 102 sometimes rattles in the bearing 105. The same applies to the case where a groove is formed on the inner peripheral surface of the bearing.
JP-A-9-42270 JP 2000-145755 A

  The problem to be solved is that the contact area between the ball head of the ball stud and the bearing decreases if a slit or a groove on the inner peripheral surface is formed in the bearing in order to improve the lubricity of the ball head of the ball joint. Since the load of the load that the inner peripheral surface receives increases, the durability of the bearing decreases.

  A ball stud composed of a long sphere having an elliptical cross section and a handle extending from the long sphere, and the ball sphere's long sphere are held in a swingable manner, and are substantially the same as the outer shape of the long sphere. In a ball joint including a bearing made of a synthetic resin having an inner circumferential shape and a housing including the bearing and having an opening for projecting a handle portion of the ball stud on one side, the axis of the ball stud serves as the axis of the bearing. The main feature is that the ball stud has a long spherical portion disposed in the bearing so as to be inclined, and has a recess formed on the inner peripheral surface of the bearing by heating to a temperature at which the bearing softens.

  A ball stud composed of a long sphere having an elliptical cross section and a handle extending from the long sphere, and the ball sphere's long sphere are held in a swingable manner, and are substantially the same as the outer shape of the long sphere. In a ball joint manufacturing method comprising: a synthetic resin bearing having an inner peripheral surface of an inner peripheral surface; and a housing including an opening for enclosing the bearing and projecting a handle portion of the ball stud on one side. A first step of disposing the ball stud long sphere in the bearing with the center substantially aligned with the bearing axis; a second step of tilting the ball stud axis with respect to the bearing axis; The main feature is that it consists of a third step of heating to a temperature at which the bearing softens, and a fourth step of hardening the bearing and then making the ball stud axis substantially coincide with the axis of the bearing. To.

  In the ball joint of the present invention, the ball joint is heated to a temperature at which the bearing softens in a state where the long sphere portion of the ball stud is disposed in the bearing so that the axis of the ball stud is inclined with respect to the axis of the bearing. Since the concave portion becomes a lubricating oil reservoir and can improve lubricity, the concave portion formed shallowly deforms the concave portion when the bearing receives a large load and holds the long sphere portion. Therefore, it is possible to suppress a decrease in the area of the inner peripheral surface of the bearing that comes into contact with the long sphere, and thus it is possible to suppress an increase in load applied to the inner peripheral surface of the bearing, thereby reducing durability. There is no.

  Further, the ball joint manufacturing method of the present invention includes a first step of disposing the long sphere portion of the ball stud in the bearing in a state where the axis of the ball stud is aligned with the axis of the bearing, and the axis of the ball stud. A second step of tilting the bearing with respect to the axis of the bearing, a third step of heating to a temperature at which the bearing softens, and a fourth step of hardening the bearing and aligning the ball stud axis with the bearing axis. Therefore, the ball joint of the present invention can be easily manufactured.

  The purpose of improving the lubricity of the ball joint was achieved without reducing the durability of the bearing.

  Shown in FIG. 1 is a ball joint 1 according to an embodiment of the present invention. This ball joint 1 includes a long sphere portion 4 having a long diameter a extending in the axial direction and a short diameter b extending shorter than the long diameter a and extending in the horizontal direction, and a handle portion 3 protruding from the long sphere portion 4. 2 includes a stud 2 and a synthetic resin bearing 5 having a bearing bottom portion 26 which includes a long spherical portion 4 of the ball stud 2 in a swingable and rotatable manner and closes a bearing opening 6 on the other side, as shown in FIG. The inner peripheral surface 7 of the bearing 5 is formed with a recess 8 that forms a gap between the long sphere portion 4 and the bearing 5, particularly in the right half on the bearing opening 6 side and the left half on the bearing bottom 26 side. The one recessed portion 8 formed in the right half of the bearing opening 6 side is gradually formed thin from the bearing opening 6 side toward the equator line passing through the center of the bearing, and toward the center from both circumferential ends of the one recessed portion 8. And gradually formed. The other recess 8 formed in the left half of the bearing bottom 26 side is gradually formed thinner from the bearing bottom 26 side toward the equator line passing through the center of the bearing, and from the circumferential both ends of the other recess 8 to the center. It is formed deeper gradually. Such a bearing 5 is held in a substantially cylindrical housing 9. The housing 9 has a small opening 10 for projecting the handle 3 of the ball stud 2 on one side, and a disk-shaped closing plate 14 on the inner periphery of the other end. A large opening 11 that is caulked and fixed, and two circumferential grooves 12 and 13 that are formed on the outer peripheral surface of the housing 9 at intervals in the axial direction are formed. Between the bearing bottom 26 of the bearing 5 and the closing plate 14, a metal washer 15 and a disc spring 16 which is an elastic member positioned in the washer 15 are arranged. A dust cover 18 has a dust cover small opening 19 in which an L-shaped ring 21 having a substantially L-shaped cross section is embedded, and a dust cover large opening in which a press-fit ring 22 is embedded in the outer periphery of the handle 3 of the ball stud 2. 20 are mounted on the outer periphery of the small opening 10 of the housing 9. The ball joint 1 has a groove 12 formed on the side of the small opening 10 of the housing 9 and a groove 33 of the arm 31 in the hole 32 of the arm 31 having one circumferential groove 33 on the inner peripheral surface of the hole 32. Are press-fitted while facing each other. A C-shaped retaining ring 17, which is partially cut, is press-fitted between the groove 12 formed on the small opening 10 side of the housing 9 and the groove 33 of the arm 31, and the ball joint 1 and the arm 31 are coupled. doing.

  The manufacturing process of the said ball joint 1 is demonstrated based on figures.

  First, as shown in FIG. 4, the bearing 5 is fitted into the long sphere portion 4 of the ball stud 2 from the bearing opening 6 of the bearing 5, and the axial center O1 of the ball stud 2 and the axial center O2 of the bearing 5 are substantially coincident. To. In the state before assembly, the bearing opening 6 side of the bearing 5 has a straight portion 23 extending in the axial direction, and an inner peripheral surface 7 having substantially the same shape as the outer peripheral surface of the long sphere portion 4 is formed. Next, as shown in FIG. 5, the bearing 5 is fitted to the long sphere portion 4 of the ball stud 2 and inserted into the inner periphery of the large opening 11 of the housing 9 from the handle portion 3 side of the ball stud 2. Is deformed along the inner peripheral surface of the housing 9 on the small opening 10 side, and the bearing 5 is disposed at a predetermined position in the housing 9. Next, the washer 15 and the disc spring 16 are disposed outside the bearing bottom portion 26 of the bearing 5, and then the closing plate 14 is inserted into the inner periphery of the large opening 11 of the housing 9. Subsequently, the end of the large opening 11 of the housing 9 is caulked to the inner peripheral side to fix the closing plate 14, and a preliminary assembly 51 as shown in FIG. 6 is assembled.

  Next, as shown in FIG. 3, the axis O <b> 1 of the ball stud 2 of the preliminary assembly 51 is inclined with respect to the axis O <b> 2 of the bearing 5. Here, since the long spherical portion 4 has an elliptical cross section, when the axis O2 of the ball stud 2 is inclined, the inner peripheral surface 7 of the bearing 5 and the outer peripheral surface of the long spherical portion 4 do not coincide with each other. The outer peripheral surface of the long sphere portion 4 strongly presses the peripheral surface 7. In this state, the preliminary assembly 51 is put into a heating chamber having a heating function, subjected to heat treatment, and heated until the bearing 5 is in a desired softened state, and then the preliminary assembly 51 is taken out from the heating chamber. At this time, since the bearing 5 is softened by heating, the right half of the bearing opening 6 side and the left half of the bearing bottom 26 side along which the long spherical portion 4 of the inner peripheral surface 7 of the bearing 5 strongly presses are along the long spherical portion. And deform. In this state, the preliminary assembly 51 is cooled at room temperature and the bearing 5 is hardened again, so that the inner peripheral surface 7 of the bearing 5 is in a state in which the right half of the bearing opening 6 side and the left half of the bearing bottom 26 side are inclined elliptically. Cured with. After the bearing 5 is cured, the axial center O1 of the ball stud 2 of the pre-assembly 51 and the axial center O2 of the bearing 5 are substantially matched to return to the state before heating. At this time, the inner peripheral surface 7 of the bearing 5 is deformed. The right half portion on the bearing opening 6 side and the left half portion on the bearing bottom portion 26 side become the concave portion 8, and there is a state where there is a gap between the outer peripheral surface of the long sphere portion 4 and the inner peripheral surface 7 of the bearing 5. Thereafter, the dust cover small opening 19 is mounted on the outer periphery of the handle 3 of the ball stud 2 and the dust cover 18 large opening 20 is mounted on the outer periphery of the small opening 10 of the housing 9 to complete the ball joint 1 as shown in FIG. .

  Therefore, according to the ball joint 1 as described above, the ball stud 2 including the long sphere portion 4 having an elliptical cross section and the handle portion 3 extending from the long sphere portion 4 and the long sphere portion 4 of the ball stud 2 are swung. A synthetic resin bearing 5 having an inner peripheral surface 7 having an inner peripheral shape substantially the same as the outer peripheral shape of the long sphere portion 4 and a bearing 5, and a handle of the ball stud 2 on one side. In a ball joint including a housing 9 having a bearing opening 6 for projecting the portion 3, the long spherical portion 4 of the ball stud 2 is bearing so that the axis O 1 of the ball stud 2 is inclined with respect to the axis O 2 of the bearing 5. 5 is provided in the inner peripheral surface 7 of the bearing 5 so that the recess 8 becomes a lubricating oil reservoir and can improve lubricity. Together, since the recess 8 is formed shallower deforms when subjected to a load greater bearing 5 can hold a long bulb 4.

  Further, according to the ball joint manufacturing method of the present invention, the ball stud 2 including the long sphere portion 4 having an elliptical cross section and the handle portion 3 extending from the long sphere portion 4, and the long sphere portion 4 of the ball stud 2. And a synthetic resin bearing 5 having an inner peripheral surface 7 having an inner peripheral shape substantially the same as the outer peripheral shape of the long sphere portion 4 and a bearing 5. In a method for manufacturing a ball joint including a housing 9 having a bearing opening 6 for projecting the handle portion 3 of the ball 2, the ball stud 2 has a shaft center O 1 substantially aligned with the shaft center O 2 of the bearing 5. A first step of disposing the long sphere portion 4 in the bearing 5, a second step of inclining the axis O1 of the ball stud 2 with respect to the axis O2 of the bearing 5, and a step of heating to a temperature at which the bearing 5 softens. Three steps After curing the bearing 5, since composed of a fourth step in which the axis O1 of the ball stud 2 is substantially coincident with the axis O2 of the bearing 5 can be manufactured the ball joint.

  In the above embodiment, the long spherical portion of the ball joint has an elliptical cross section composed of a major axis extending in the axial direction and a minor axis extending shorter than the major axis in the horizontal direction, but the minor axis portion in the axial direction and the minor axis in the horizontal direction. Needless to say, an elliptical cross-section having a longer-diameter part than the part may be used.

It is a fragmentary sectional top view showing the ball joint by the Example of this invention. It is the A section enlarged view of FIG. It is a partial section top view showing the state when the ball stud of the ball joint by the example of the present invention is inclined. It is a fragmentary sectional top view showing the 1st assembly | attachment process of the ball joint by the Example of this invention. It is a fragmentary sectional top view showing the 2nd assembly | attachment process of the ball joint by the Example of this invention. 1 is a partial cross-sectional plan view illustrating a ball joint preliminary assembly according to an embodiment of the present invention. It is a fragmentary sectional top view showing the conventional ball joint. It is a cross-sectional top view showing the bearing of the conventional ball joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ball joint 2 Ball stud 3 Handle part 4 Long ball part 5 Bearing 6 Bearing opening 7 Inner peripheral surface 8 Recessed part 9 Housing O1 Shaft center (ball stud)
O2 shaft center (bearing)

Claims (2)

  A ball stud (2) composed of a long spherical portion (4) having an elliptical cross section and a handle portion (3) extending from the long spherical portion (4), and a long spherical portion (4) of the ball stud (2) And a bearing (5) made of synthetic resin having an inner peripheral surface (7) having an inner peripheral shape substantially the same as the outer peripheral shape of the long sphere portion (4), and the bearing ( 5) and a housing (9) having a bearing opening (6) for projecting the handle (3) of the ball stud (2) on one side, the axial center of the ball stud (2) The long spherical portion (4) of the ball stud (2) is disposed in the bearing (5) so that (O1) is inclined with respect to the axis (O2) of the bearing (5), and the bearing (5 ) Is formed by heating to a temperature at which the Ball joint, characterized in that it comprises on the inner peripheral surface of the bearings (5) (7).   A ball stud (2) composed of a long spherical portion (4) having an elliptical cross section and a handle portion (3) extending from the long spherical portion (4), and a long spherical portion (4) of the ball stud (2) And a bearing (5) made of synthetic resin having an inner peripheral surface (7) having an inner peripheral shape substantially the same as the outer peripheral shape of the long sphere portion (4), and the bearing ( 5) and a housing (9) having a bearing opening (6) for projecting a handle (3) of the ball stud (2) on one side, the ball stud (1), The long spherical portion (4) of the ball stud (2) is disposed in the bearing (5) with the axial center (O1) of (2) substantially aligned with the axial center (O2) of the bearing (5). And the bearing of the ball stud (2) axial center (O1) 5) a second step of inclining with respect to the axis (O2), a third step of heating to a temperature at which the bearing (5) softens, and after the bearing (5) is cured, the ball stud ( 2) A ball joint manufacturing method comprising the fourth step of substantially matching the axis (O1) of the bearing (5) with the axis (O2) of the bearing (5).

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