JP2012021600A - Ball joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball joint which exhibits a satisfactory sealing property by maintaining a proper assembling state of a dust cover with respect to a ball stud even when a film part of the dust cover is strongly pulled and which has an improved sealing property of the dust cover while maintaining a swingable range of the ball stud.SOLUTION: The ball joint includes: the ball stud 12 having a ball head part; a socket which stores the ball head part in a turnable manner and has an opening part on one side; and the dust cover 36, wherein the ball stud 12 includes a first shaft part 20, a flange part 22 having an outer diameter larger than that of the first shaft part 20 and a second shaft part 24 having an outer diameter smaller than that of the flange part 22, and wherein the dust cover 36 includes an inner circumferential part 44 fit to the first shaft part 20 and a lip part 48 to make close contact with the second shaft part 24.

Description

The present invention relates to a ball joint used mainly as a connecting device for a vehicle link mechanism, and more particularly to a ball joint in which the sealing performance of a dust cover does not deteriorate.

  2. Description of the Related Art Conventionally, as a ball joint used in a vehicle suspension mechanism or steering mechanism, for example, one described in Patent Document 1 is known.

FIG. 8 is an explanatory view showing a conventional ball joint described in Patent Document 1. As shown in FIG. In FIG. 8, a ball joint 100 is a lip that elastically adheres to the end 110a of the small-diameter opening 110 of the dust cover 106 made of an elastic material such as rubber over the entire circumference of the outer peripheral surface 104b of the flange 104 of the ball stud 102. A portion (annular protrusion) 112 is provided, and the end portion 110 a of the small-diameter opening 110 is in close contact with the flange end surface 104 a of the ball stud 102 by the urging force of the dust cover 106.

Japanese Utility Model Publication No. 1-139119

  However, the elastic force of the dust cover 106 decreases with time, such as thermal deterioration, and in a low temperature environment, the elastic material such as rubber is cured and the elastic force is significantly reduced compared to that in a normal temperature environment. . Therefore, in such a conventional ball joint 100, as the elastic force of the dust cover 106 decreases, the extension side tension and the compression side pressing force of the dust cover 106 when the ball stud 102 swings increase, and the lip portion Adhesiveness between 112 and the flange portion outer peripheral surface 104b cannot be maintained.

  In particular, when the ball stud 102 swings in a low-temperature environment, as shown in FIG. 9, the side on which the film portion (bellows portion) 108 of the dust cover 106 extends, that is, the outer peripheral surface of the socket 114 to which the dust cover 106 is attached. The extended side 108a in which the distance between the flange portion 104 of the ball stud 102 and 114a is increased is that the small-diameter opening 110 of the dust cover 106 is strongly pulled in the direction of the socket 114 by the hardened film portion 108, so The assembled state cannot be maintained, and the sealing performance of the dust cover 106 is deteriorated.

  Further, the side on which the film part 108 of the dust cover 106 shrinks, that is, the compression side 108b in which the distance between the socket outer peripheral surface 114a to which the dust cover 106 is attached and the flange part 104 of the ball stud 102 is shortened is caused by the hardened film part 108. The small-diameter opening 110 of the dust cover 106 may be strongly pushed out toward the outer side of the flange portion 104. In this case, the proper assembly state with respect to the ball stud 102 cannot be maintained, and the sealing performance of the dust cover 106 is deteriorated.

  In this way, when the sealing performance of the dust cover 106 is lowered, in order to maintain the proper assembly state of the small diameter opening 110 and prevent the sealing performance from being lowered, the thickness of the lip portion 112 is increased and the ball stud is increased. It is necessary to increase the adhesion force due to elasticity to the flange portion outer peripheral surface 104b of 102.

  However, when the radial thickness of the lip portion 112 is increased, the outer diameter of the lip portion 112 with the dust cover 106 attached to the ball stud 102 increases, and the lip portion 112 and the film portion 108 start to interfere with each other. The swing angle of the stud 102 becomes small. Further, when the interference part 108c between the lip part 112 and the film part 108 deteriorates due to wear or the like and breaks, the sealing performance of the dust cover 106 is lost.

  Therefore, the conventional ball joint described in Patent Document 1 has a problem that the sealability of the dust cover cannot be improved while maintaining the swingable range of the ball stud.

The present invention maintains the dust cover properly assembled to the ball stud even when the dust cover film is pulled strongly, and can provide a good sealing performance, while maintaining the swingable range of the ball stud. An object of the present invention is to provide a ball joint that can improve the sealing performance of a dust cover.

  In order to achieve this object, the present invention is configured as follows. First, the present invention provides a ball stud that has a ball head at one end of the stud portion and a handle at the other end, and a socket that rotatably accommodates the ball head and has an opening from which the stud portion protrudes. And a ball joint including a dust cover having a small diameter opening to be attached to the stud and a large diameter opening to be attached to the socket and having elasticity.

  In such a ball joint, the ball stud has a first shaft portion, a flange portion having an outer diameter larger than the first shaft portion, and an outer diameter of the handle portion side end portion in order from the ball head side to the stud portion. The dust cover has a small-diameter opening, an inner peripheral portion that is elastically fitted to the first shaft portion, and a lip portion that is elastically fitted to the second shaft portion. Is provided.

  Here, the second shaft portion of the ball stud has a substantially constant outer diameter from the end portion on the ball head side to the end portion on the handle portion side. In this case, the end portion on the handle portion side is on the ball head side. The outer diameter may gradually decrease toward the handle portion side.

  Alternatively, the outer diameter of the second shaft portion of the ball stud gradually decreases from the ball head side end portion toward the handle portion side end portion.

Alternatively, the outer diameter of the ball stud gradually decreases from the ball head side end portion of the collar portion toward the handle portion side end portion of the second shaft portion.

  According to the present invention, the ball stud has a first shaft portion into which the inner peripheral portion of the dust cover small-diameter opening is fitted, a flange portion having a larger diameter than the first shaft portion, and a columnar or conical shape having a smaller diameter than the flange portion. By providing the second shaft portion and fitting the lip portion of the dust cover small-diameter opening to the second shaft portion, movement of the lip portion in the socket side direction is suppressed.

  Thereby, since the proper assembly | attachment state of the dust cover with respect to a ball stud can be maintained, the favorable sealing performance of a dust cover can be exhibited in all the environments where a ball joint is used.

Also, with the dust cover attached to the ball stud, the lip thickness can be increased without increasing the lip outer diameter, so the dust cover sealability is maintained while maintaining the swingable range of the ball stud. Can be improved.

Explanatory drawing which shows embodiment of the ball joint which concerns on this invention Explanatory drawing which shows the dust cover and ball stud of FIG. Explanatory drawing which expands and shows the fitting part of the ball stud and dust cover of FIG. Explanatory drawing which shows contrast with the lip | rip part of FIG. 1 and the lip | rip part of the conventional ball joint Explanatory drawing which shows other embodiment of the ball joint which concerns on this invention. Explanatory drawing which shows other embodiment of the ball joint which concerns on this invention. Explanatory drawing which shows other embodiment of the ball joint which concerns on this invention. Explanatory drawing showing a conventional ball joint Explanatory drawing which shows the state of a dust cover when the ball stud of FIG. 8 rocks

  FIG. 1 is an explanatory view showing an embodiment of the ball joint of the present invention. In FIG. 1, the ball joint 10 includes a ball stud 12, a ball seat 30, a socket 32, and a dust cover 36.

  In the ball joint 10, the ball head 16 formed at one end of the ball stud 12 is assembled into a socket 32 via a ball seat 30, and an opening 34 of the socket 32 is crimped to swing and rotate the ball stud 12. Supports freely. A dust cover 36 is installed between the ball stud 12 and the socket 32 to prevent water and dust from entering through the opening 34.

  FIG. 2 is an explanatory view showing each of the dust cover 36 and the ball stud 12 of FIG. 1, FIG. 2A shows a cross section of the dust cover 36, and FIG. 2B shows the ball stud 12. 2A, the dust cover 36 is formed of an elastic material such as rubber. The dust cover 36 has a small-diameter opening 40 at one end and a large-diameter opening 50 at the other end. A peripheral portion 54 in which a metal reinforcing ring 52 is embedded is formed. The reinforcing ring 52 secures rigidity and is fixed to the socket 32.

  In the present embodiment, the reinforcing ring 52 is embedded in the large-diameter opening 50, but the large-diameter opening 50 may be fixed to the socket 32 in other forms. Further, the shape of the film portion 38 is not limited to the shape shown in FIG. 2A, and may be other shapes.

  2B, the ball stud 12 has a ball head 16 provided at one end of the stud portion 14, and the stud portion 14 has a neck portion 18, a first shaft portion 20, a collar portion 22, A biaxial portion 24, a locking portion 26, and a handle portion 28 are provided.

  The neck portion 18, the first shaft portion 20, and the second shaft portion 24 each have a columnar shape with a substantially constant outer diameter, but the values of the outer diameters are different. Further, the outer diameter of the flange portion 22 is larger than that of the first shaft portion 20, and the outer diameter of the second shaft portion 24 is smaller than that of the flange portion 22.

  In the present embodiment, there are steps on the outer periphery of the cylindrical neck 18 and the first shaft portion 20, but this is a design matter, and depending on the specifications required for the ball joint, The neck portion 18 and the first shaft portion 20 may be integrally formed in a truncated cone shape (tapered shape) without providing a step on the outer peripheral portion of the one shaft portion 20.

  In this embodiment, a screw is formed on the outer periphery of the handle portion 28 and a locking portion 26 is provided. The handle portion 28 is fixed to a part to be assembled, for example, a suspension arm with a nut. The arrangement and shape of the handle portion 28 are arbitrary depending on the mounting method of the ball joint 10.

  FIG. 3 is an enlarged explanatory view showing a fitting portion between the ball stud 12 and the dust cover 36 of FIG. 1, and the dust cover 36 shown in FIG. B) is inserted into the handle portion 28 side of the ball stud 12 and the small-diameter opening 40 is engaged with a predetermined position of the stud portion 14 beyond the locking portion 26.

  In FIG. 3, the dust cover 36 has an end surface 42 that abuts against the first shaft portion side end surface 22 a of the flange portion 22, and an inner peripheral portion 44 that is elastically fitted to the first shaft portion 20 of the ball stud 12. The inner peripheral surface 44a of the peripheral portion 44 and the outer peripheral surface 20a of the first shaft portion 20 are in close contact with each other to ensure sealing performance.

  Note that the shape of the end surface 42 of the dust cover 36 is not limited to the shape shown in FIG. 3, and may be any other shape as long as it can contact the first shaft side end surface 22 a of the flange portion 22. .

  Further, the lip portion 48 is brought into close contact with the outer peripheral surface 24a of the second shaft portion 24 by elasticity, thereby reinforcing the sealing performance of the small diameter opening portion 40 when the film portion 38 is pulled. In this state, gaps 46 are formed at the inner corners of the lip portion 48 and the inner peripheral portion 44, and the degree of freedom of elastic deformation of the lip portion 48 is ensured, so that the lip portion 48 adheres to the outer peripheral surface 24a. Is certain.

  Therefore, even when the ball stud 12 swings and the small-diameter opening 40 of the dust cover 36 is pulled by the film portion 38, the flange portion 22 of the ball stud 12 causes the lip portion 48 of the dust cover 36 to move toward the socket 32 side. Therefore, the proper assembly state of the small-diameter opening 40 of the dust cover 36 with respect to the ball stud 12 can be maintained.

  Note that the lip portion 48 of the dust cover 36 may be in contact with the flange portion 22 as long as the lip portion 48 is in close contact with the outer peripheral surface 24a of the second shaft portion 24 as long as the adhesiveness with the outer peripheral surface 24a is not impaired.

  FIG. 4 is an explanatory view showing the comparison between the present invention and the conventional example of the lip portion, and FIG. 4 (A) shows the lip portion 48 of the dust cover 36 according to the present invention shown in FIG. B) shows a lip portion 112 of the dust cover 106 of the conventional example shown in FIG.

  When the outer diameter D1 of the lip 48 shown in FIG. 4A is equal to the outer diameter D2 of the lip 112 shown in FIG. 4B, the thickness W1 of the lip 48 is greater than the thickness W2 of the lip 112. Can be configured large.

  That is, by making the outer diameter of the second shaft portion 24 smaller than the outer diameter of the flange portion 22, while ensuring the size of the first shaft portion side end surface 22a of the flange portion 22 with which the end surface 42 of the dust cover 36 abuts. The thickness W1 of the lip 48 can be increased in the inner diameter direction of the second shaft portion 24, and the sealing performance of the dust cover can be improved.

  Even if the thickness W1 of the lip 48 is increased with respect to the thickness W2 of the lip 112, the outer diameter D1 of the lip 48 is the same as the outer diameter D2 of the lip 112. The maximum swing angle can be maintained at the maximum swing angle of the ball stud 102.

  5-7 is explanatory drawing which shows other embodiment of the ball joint which concerns on this invention, and has shown the fitting part of the ball stud 12 and the dust cover 36. As shown in FIG.

  In FIG. 5, the step part 22c between the flange part 22 and the second shaft part 24 of the ball stud 12 is different from the shape of the step part 22b in FIG. The step portion 22c, that is, the end portion on the second shaft portion side of the flange portion 22 has an outer diameter from the first shaft portion 20 side to the second shaft portion 24 side (from the spherical head 16 side to the handle portion 28 side). The shape gradually decreases.

  In the dust cover 36, the lip portion 48 is elastically adhered to the outer peripheral surface 24 a of the second shaft portion 24, the ball stud 12 is swung, and the small-diameter opening 40 of the dust cover 36 is pulled by the film portion 38. However, the movement of the lip portion 48 of the dust cover 36 toward the socket 32 side is suppressed by the step of the flange portion 22 of the ball stud 12, and the small-diameter opening 40 of the dust cover 36 is properly assembled to the ball stud 12. Can be maintained.

  In FIG. 6, the shape of the inclined portion 24 b where the second shaft portion 24 of the ball stud 12 is connected to the flange portion 22 is different from that in FIG. 3. The inclined portion 24b, that is, the collar portion side of the second shaft portion 24 is directed from the collar portion 22 side end portion to the locking portion 26 side end portion (from the ball head 16 side end portion to the handle portion 28 side end portion). The outer diameter gradually decreases.

  In the dust cover 36, the lip portion 48 is in close contact with the inclined portion 24 b of the second shaft portion 24 due to elasticity, the ball stud 12 swings, and the small-diameter opening 40 of the dust cover 36 is pulled by the film portion 38. However, the movement of the lip portion 48 of the dust cover 36 toward the socket 32 side is suppressed by the inclination of the inclined portion 24b, and the proper assembly state of the small diameter opening 40 of the dust cover 36 with respect to the ball stud 12 is maintained. Can do.

  In FIG. 7, the shapes of the flange portion 22 and the second shaft portion 24 of the ball stud 12 are different from those in FIG. 3. That is, there is no level | step difference which divides the collar part 22 and the 2nd axial part 24, from the 1st axial part side edge part 22a of the collar part 22 to the latching | locking part 26 edge part (from the ball head 16 side edge part of the collar part 22). The tapered portion 24c has a shape in which the outer diameter gradually decreases toward the handle portion 28 side end portion of the second shaft portion 24.

  The dust cover 36 has a lip portion 48 that is in close contact with the taper portion 24c due to elasticity, and even if the ball stud 12 swings and the small-diameter opening 40 of the dust cover 36 is pulled by the film portion 38, the taper portion 24c. Accordingly, the movement of the lip portion 48 of the dust cover 36 toward the socket 32 side is suppressed, and the proper assembly state of the small-diameter opening 40 of the dust cover 36 with respect to the ball stud 12 can be maintained.

The present invention is not limited to a ball joint used as a connecting device of a vehicle link mechanism, but can be applied to any ball joint provided with a dust cover, and is not limited to the above-described embodiment, and the object and advantages thereof are impaired. Appropriate modifications that do not occur are included.

10: Ball joint 12: Ball stud 14: Stud portion 16: Ball head 18: Neck portion 20: First shaft portion 22: Saddle portion 24: Second shaft portion 26: Locking portion 28: Handle portion 30: Ball seat 32 : Socket 34: opening 36: dust cover 38: film part 40: small diameter opening 42: end face 44: inner peripheral part 46: gap 48: lip part 50: large diameter opening part 52: reinforcing ring 54: peripheral part 100: Ball joint 102: Ball stud 104: Flange portion 106: Dust cover 108: Film portion 110: Small diameter opening portion 112: Lip portion 114: Socket

Claims (5)

A ball stud having a ball head at one end of the stud portion and forming a handle at the other end, a socket having the ball head rotatably accommodated and a socket provided with an opening from which the stud portion protrudes; In a ball joint comprising a small-diameter opening to be attached to a stud and a dust cover having a large-diameter opening to be attached to the socket and having elasticity,
The ball stud is in order from the ball head side to the stud portion,
A first shaft portion;
A flange portion having an outer diameter larger than that of the first shaft portion;
A second shaft portion having an outer diameter of the handle portion side end portion smaller than the flange portion;
Provided,
The dust cover is in the small diameter opening,
An inner peripheral portion that is elastically fitted to the first shaft portion;
A lip portion that is elastically fitted to the second shaft portion;
A ball joint characterized by providing
The ball joint according to claim 1, wherein the second shaft portion of the ball stud is
A ball joint characterized in that the outer diameter is substantially constant from the ball head side end to the handle portion side end.
The ball joint according to claim 2, wherein the flange portion of the ball stud is
A ball joint characterized in that the outer diameter of the handle portion side end portion gradually decreases from the ball head side toward the handle portion side.
The ball joint according to claim 1, wherein the second shaft portion of the ball stud is
A ball joint characterized in that the outer diameter gradually decreases from the ball head side end toward the handle side end.
The ball joint according to claim 1, wherein the ball stud is
The ball joint, wherein an outer diameter gradually decreases from a ball head side end portion of the flange portion toward a handle portion side end portion of the second shaft portion.

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