Sealing structure of ball joint

Abstract

This ball joint seal structure has a ferrule ring interposed between the small-diameter opening of a dust cover and a knuckle. The ball joint connects the knuckle to a stud, and a ball head on the end of the stud is housed in a socket so as to be rockable and rotatable. A dust cover has a large-diameter opening surrounding the socket that houses the ball head, and the small-diameter opening surrounding the stud, the large-diameter opening and the small-diameter opening being connected by a membrane. The ferrule ring is provided with an annular portion that suppresses entrance of dust through a notch that occurs when, for example, a pinch bolt knuckle is employed, and has, at the outer peripheral end, an inclined portion that is inclined toward the dust cover side.

Description

Technical Field

[0001] The present disclosure relates to a seal structure of a ball joint and a method for attaching a ferrule ring.

Background Art

[0002] Ball joints are widely used in automotive suspension and steering systems. A ball joint has a structure in which a knuckle is fixed to one end of a stud, and a ball head provided at the other end of the stud is housed and held in a socket. In order to smoothly operate the ball head of the stud, the socket is filled with grease.

[0003] The dust cover attached to the ball joint prevents the leakage of grease and blocks the entry of foreign matter into the socket. Such a dust cover is a membranous member having a small-diameter opening and a large-diameter opening. The stud is elastically covered with a seal lip provided at the small-diameter opening, and the accommodation region of the ball head is surrounded and sealed at the large-diameter opening.

[0004] There are two types of connection structures between the stud and the knuckle of the ball joint: a taper mating method and a pinch bolt method.

[0005] The taper mating method is a structure in which the outer peripheral surface of the stud and the inner peripheral surface of the mounting hole of the knuckle into which the stud is inserted are axially aligned with each other by taper surfaces, and the stud and the knuckle are fixed in this state.

[0006] The pinch bolt method is a structure in which a notch that is axially cut is provided in the knuckle, and a fastener such as a bolt and a nut is used to narrow the interval of the notch, thereby clamping and fixing the knuckle to the stud (see Patent Document 1).

[0007] In recent years, with the popularization of EVs (Electric Vehicles), there has been an increasing demand for space-saving in the undercarriage. Of course, not only in the undercarriage but also in various parts such as the engine room in the field of automobiles, space-saving is required. For such a demand for space-saving, a ball joint using a pinch bolt method is more adaptable than a taper fitting method.

[0008] On the other hand, a ball joint using a pinch bolt method has a structure in which a notch is provided in the knuckle. Therefore, it is vulnerable to the intrusion of dust into the notch, and often a dust lip is not provided at the small-diameter opening of the dust cover. For this reason, rust occurs significantly on the stud and knuckle parts of the ball joint, and the rust increases the wear of the seal lip provided at the small-diameter opening of the dust lip, thereby deteriorating the sealing function.

[0009] Therefore, for example, as shown in International Publication No. 2017 / 018169 (hereinafter referred to as "Patent Document 1"), a metal annular member called a ferrule ring (referred to as "annular plate 6" in Patent Document 1) is interposed between the knuckle and the small-diameter opening of the dust cover to suppress the intrusion of foreign matter from the notch. In this case, it is also an advantage of providing the ferrule ring that it becomes easy to adopt a structure in which a dust lip is provided at the small-diameter opening of the dust cover.

[0010] Regarding the ferrule ring, for example, as described in Japanese Patent Application Laid-Open No. 2011-064208 (hereinafter referred to as "Patent Document 2"), a ferrule ring having a shape in which the outer peripheral edge is bent toward the dust cover is also known (referred to as "ferrule 9" in Patent Document 2). Such a shape of the ferrule ring is a device for preventing dust from entering the dust cover when a so-called opening phenomenon occurs in which a gap is generated between the ferrule ring on the knuckle side and the small-diameter opening of the dust cover (see FIG. 8 of Patent Document 2) (see paragraph

[0010] of Patent Document 2).

[0011] Japanese Patent Application Laid-Open No. 2016-125625 (hereinafter referred to as "Patent Document 3") describes a "ferrule ring 150" shaped such that not only is the outer peripheral edge bent toward the dust cover side, but it also holds the small-diameter opening of the dust cover in a wrapped manner. According to such a box-shaped ferrule ring, it is presumed that the small-diameter opening is held within the box shape, suppressing the occurrence of the opening phenomenon. Patent Document 3 states that "the posture of the seal portion is stably maintained within the second annular member" (see paragraph

[0010] of Patent Document 3).

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0013] In a ferrule ring with a bent outer peripheral edge as described in Patent Document 2, sliding occurs between the bent outer peripheral edge and the small-diameter opening of the dust cover when the stud rocks and rotates. The repeatedly occurring sliding promotes wear of the small-diameter opening, so improvement is desired.

[0014] For a ferrule ring that holds the small-diameter opening of the dust cover in a wrapped manner as described in Patent Document 3, it is necessary to process the ferrule ring to wrap the small-diameter opening, which increases the number of manufacturing steps. If one does not want to increase the number of manufacturing steps, a structure that wraps the small-diameter opening with the ferrule ring cannot be adopted.

[0015] An object of the present disclosure is to suppress an increase in sliding torque between a ferrule ring on the knuckle side and a small-diameter opening of a dust cover when the stud swings or rotates.

Means for Solving the Problem

[0016] One aspect of the seal structure of a ball joint is a seal structure of a ball joint in which a ferrule ring is interposed between a knuckle connected to a stud of the ball joint and a small-diameter opening of a dust cover covering the stud, and an outer peripheral end of the ferrule ring is inclined toward the dust cover side at an angle forming an obtuse angle with respect to a surface on the inner peripheral side of the ferrule ring. has an inclined portion It is. As an example, the small-diameter opening of the dust cover An annular reinforcing ring is embedded therein, and the reinforcing ring exposes a portion facing the ferrule ring from the small-diameter opening and contacts the ferrule ring. The inclination of the ferrule ring portion is smaller in diameter than the minimum-diameter portion of Moreover, the inclined portion of the ferrule ring is provided at a position that covers the small-diameter opening from the outer peripheral side and does not interfere with the small-diameter opening. it. As another example, the small-diameter opening of the dust cover An annular reinforcing ring is embedded therein, exposing a portion facing the ferrule ring. The inclination of the ferrule ring portion contacts the ferrule ring on the inner peripheral side of the minimum-diameter portion of Moreover, the inclined portion of the ferrule ring is provided at a position that covers the small-diameter opening from the outer peripheral side and does not interfere with the small-diameter opening. the inclination.

[0017] Another aspect of the seal structure of a ball joint includes a ball joint that connects a knuckle to a stud and accommodates a ball head provided at an end of the stud in a socket so as to be swingable and rotatable, a large-diameter opening surrounding an accommodation region of the socket that houses the ball head, and a small-diameter opening surrounding the stud, a dust cover that connects the large-diameter opening and the small-diameter opening with a film portion, and a ferrule ring interposed between the knuckle and the small-diameter opening of the dust cover, wherein the ferrule ring includes an annular portion that contacts one surface of the knuckle on the dust cover side, and an inclined portion provided on an outer peripheral side of the annular portion and inclined toward the dust cover side at an angle forming an obtuse angle with respect to the annular portion. As an example, the small-diameter opening of the dust cover An annular reinforcing ring is embedded therein, and the reinforcing ring exposes a portion facing the ferrule ring from the small-diameter opening and contacts the ferrule ring. The inclination of the ferrule ring portion is smaller in diameter than the minimum-diameter portion of Moreover, the inclined portion of the ferrule ring is provided at a position that covers the small-diameter opening from the outer peripheral side and does not interfere with the small-diameter opening. it. As another example, the small-diameter opening of the dust cover An annular reinforcing ring is embedded therein, exposing a portion facing the ferrule ring. the inclination of the ferrule ring portion contacts the ferrule ring on the inner circumferential side of the minimum diameter portion of Moreover, the inclined portion of the ferrule ring is provided at a position that covers the small-diameter opening from the outer peripheral side and does not interfere with the small-diameter opening. it.

Advantages of the Invention

[0019] When the stud swings or rotates, it is possible to suppress an increase in the sliding torque between the ferrule ring on the knuckle side and the small-diameter opening of the dust cover.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0021] The embodiments will be described with reference to the drawings. This embodiment is an example of a ball joint 101 that connects a lower arm (not shown), which is an object to be jointed, and a knuckle 201. The seal structure of the ball joint 101 in this embodiment defines a structure for sealing between the knuckle 201 and the small-diameter opening 133 of the dust cover 131, which will be described later.

[0022] The embodiments will be described along the following items. [First Embodiment] 1. Configuration (1) Ball joint (2) Dust cover (3) Ferrule ring 2. Method of attaching the ferrule ring (1) Manufacture of the ferrule ring (2) Fixing of the ferrule ring (3) Comparative examples (a) Comparative Example 1 (b) Comparative Example 2 (c) Comparative Example 3 3. Operational effects (1) Basic operational effects (2) Countermeasures against the mouth-opening phenomenon (3) Suppression of an increase in sliding torque (4) Prevention of an increase in the number of manufacturing processes [Second Embodiment] [Modification Example]

[0023] [First Embodiment] The first embodiment will be described with reference to FIGS. 1 to 5.

[0024] 1. Configuration (1) Ball joint As shown in FIG. 1, the ball joint 101 has a basic structure in which a ball head portion 112 provided on a ball stud 111 is held in a socket 121 so as to be swingable and rotatable, and this holding region is sealed with a dust cover 131. In FIG. 1, the swing direction of the ball joint 101 with respect to the axis AX is indicated by an arrow A, and the rotation direction is indicated by an arrow B.

[0025] The ball stud 111 is a metal member having a rod-shaped stud 113 extending from the ball head portion 112. The stud 113 extends from the ball head portion 112 so that the axis AX passes through the center point of the ball head portion 112. The ball joint 101 connects the stud 113 to the knuckle 201. The knuckle 201 is a metal member having a thick flat plate shape.

[0026] As shown in FIG. 2, the knuckle 201 has a mounting hole 202 through which the stud 113 passes, and a notch 203 that communicates the mounting hole 202 with the external space over the entire length in the axial direction (coinciding with the direction of the axis AX of the ball joint 101) is provided. Bolt holes 204 are provided on both sides of the knuckle 201 sandwiching the notch 203, and a nut 206 is screwed to the tip of a bolt 205 passing through the bolt hole 204. The bolt 205 and the nut 206 constitute a fastening tool 207, and by tightening the bolt 205, it is possible to reduce the interval of the notch 203, that is, the inner diameter of the mounting hole 202. Therefore, by tightening the bolt 205, the stud 113 can be fixed to the knuckle 201.

[0027] As shown in FIG. 1, the stud 113 has a large-diameter portion 113a, a seal portion 113b, and a mounting portion 113c in order from the side of the ball head portion 112 toward the tip portion.

[0028] The large-diameter portion 113a is the portion having the largest diameter among the stud 113.

[0029] The seal part 113b is a part that contacts the seal lip 141 provided in the small-diameter opening 133 (described later) of the dust cover 131 and causes the seal lip 141 to perform a sealing function. The seal part 113b has a uniform diameter over its entire length.

[0030] The mounting part 113c is a part that is inserted into the mounting hole 202 of the knuckle 201 and fixed in the mounting hole 202 by tightening the fastener 207. The outer diameter of the mounting part 113c is uniform over its entire length. A step is provided between the mounting part 113c and the seal part 113b, and the mounting part 113c is formed with a smaller diameter than the seal part 113b. When the mounting part 113c is inserted into the mounting hole 202 of the knuckle 201, the knuckle 201 abuts against the step between it and the seal part 113b and is positioned at this position.

[0031] The socket 121 houses a resin bearing 123 in a cylindrical housing 122 with both ends open, and the bottom is closed by a bottom plate 124. One end of the housing 122 that opens is the opening 125, and the stud 113 part of the ball stud 111 is exposed to the outside from this opening 125. The bearing 123 is housed in the housing 122 without a gap and is fixedly held, and holds the ball head 112 of the ball stud 111 so as to be swingable and rotatable. The contact area between the bearing 123 and the ball head 112 is filled with lubricating grease (not shown).

[0032] The housing 122 forms a mounting part 126 on the outer peripheral surface near the opening 125. The mounting part 126 is a small-diameter opening part in a stepped shape for attaching the dust cover 131.

[0033] (2) Dust cover The dust cover 131 is a film-like member formed of a rubber-like elastic member. The dust cover 131 is provided with a small-diameter opening 133 on one end side and a large-diameter opening 134 on the other end side of a cup-shaped film part 132. Because it is a rubber-like elastic member, the dust cover 131 has flexibility and elastic restoring force.

[0034] The large-diameter opening 134 has a clamp 135 that is fitted and attached to a mounting portion 126 provided on the outer peripheral surface of the housing 122. The clamp 135 is a metal annular member embedded in the large-diameter opening 134 made of rubber. By fitting the large-diameter opening 134 into the mounting portion 126 of the housing 122, the rubber-like elastic member is elastically deformed, and the large-diameter opening 134 is fixedly attached to the housing 122.

[0035] As shown in FIG. 3, the small-diameter opening 133 is provided with a seal lip 141 and a dust lip 151. These lips 141 and 151 are both formed integrally with the dust cover 131 to form an annular shape. The seal lip 141 is disposed at the inner peripheral portion of the small-diameter opening 133, and the dust lip 151 is disposed at the opening end portion of the small-diameter opening 133.

[0036] The seal lip 141 elastically covers the seal portion 113b of the stud 113 through the cylindrical portion 304 of the ferrule ring 301 described later, and seals the space S that houses the ball head portion 112 defined by the film portion 132 of the dust cover 131.

[0037] The dust lip 151 has two lip ends 151a that project annularly from the opening end of the small-diameter opening 133 facing the knuckle 201. A ferrule ring 301 described later is interposed between the knuckle 201 and the small-diameter opening 133. The lip ends 151a of the dust lip 151 elastically deform and contact the lower surface of the knuckle 201 through the ferrule ring 301, preventing foreign matter from entering the space S in the dust cover 131 from the outside.

[0038] A reinforcing ring 161 is embedded in the small-diameter opening 133 of the dust cover 131. The reinforcing ring 161 is an annular metal member and has an L-shaped cross section. One piece of the L shape extends in the axial direction of the dust cover 131, that is, in the direction along the axis AX of the ball stud 111, and the other piece of the L shape extends in a direction orthogonal to the axis of the dust cover 131.

[0039] (3) Ferrule ring As shown in FIGS. 3 and 4(A), the ferrule ring 301 is mainly composed of an annular portion 302 that is in surface contact with the lower surface 201U, which is one surface on the dust cover 131 side of the knuckle 201. It has an inclined portion 303 on the outer peripheral edge and a cylindrical portion 304 on the inner peripheral edge, respectively. The ferrule ring 301 is an integrally formed product obtained by forming these annular portion 302, inclined portion 303, and cylindrical portion 304 by pressing.

[0040] The annular portion 302 is a flat annular body that contacts the lower surface 201U of the knuckle 201. Due to their mutual contact, the intrusion of foreign matter from the outside is suppressed between the knuckle 201 and the ferrule ring 301.

[0041] As shown in FIG. 5, the inclined portion 303 provided at the outer peripheral end of the ferrule ring 301 is inclined toward the dust cover 131 side at an obtuse angle with respect to the annular portion 302 that forms the inner peripheral side surface of the ferrule ring 301.

[0042] As an example, the inclined portion 303 is formed by bending the outer peripheral end of the ferrule ring 301 by, for example, 30 degrees with respect to a virtual plane including the annular portion 302. As a result, the inclined portion 303 is inclined toward the dust cover 131 side at an angle of 150 degrees with respect to the annular portion 302. At this time, the inclined portion 303 is set at an angle of 30 degrees with respect to the lower surface 201U of the knuckle 201 when the ferrule ring 301 is incorporated (see FIG. 3).

[0043] The inclination angle of the inclined portion 303 of 150 degrees is, of course, just an example. The inclined portion 303 may be inclined at another angle. If the inclined portion 303 is formed by bending the outer peripheral end of the ferrule ring 301 in this case, the inclined portion 303 can be obtained by bending the outer peripheral end of the ferrule ring 301 at an angle not exceeding 90 degrees.

[0044] As shown in FIG. 3, the dust lip 151 provided at the small-diameter opening 133 of the dust cover 131 has a smaller diameter than the inclined outer peripheral end (inclined portion 303) of the ferrule ring 301. More specifically, the outer diameter of the lip end 151a on the outer peripheral side of the dust lip 151 is smaller than the circumference forming the boundary between the annular portion 302 and the inclined portion 303. As a result, the dust lip 151 contacts the ferrule ring 301 on the inner peripheral side of the inclined portion 303.

[0045] At this time, as a mode in which the dust lip 151 contacts the ferrule ring 301 on the inner peripheral side of the inclined portion 303, (Mode 1) When the stud 113 of the ball joint 101 is not inclined, the dust lip 151 contacts the ferrule ring 301 on the inner peripheral side of the inclined portion 303. (Mode 2) Even when the stud 113 of the ball joint 101 is inclined, the dust lip 151 contacts the ferrule ring 301 on the inner peripheral side of the inclined portion 303. Two modes can occur. In practice, either Mode 1 or Mode 2 may be used. However, the effect of reducing the sliding torque described later is higher in Mode 2.

[0046] As shown in FIG. 1, a seal portion 113b of the stud 113 that forms a part of the ball stud 111 fits into the cylindrical portion 304. The inner diameter of the cylindrical portion 304 has the same dimension as the outer diameter of the seal portion 113b.

[0047] As shown in FIG. 4(A), the cylindrical portion 304 of the ferrule ring 301 before incorporation is formed in a straight tube shape that fits the seal portion 113b of the stud 113. On the other hand, as shown in FIGS. 1, 3, 4(B), and 5, the cylindrical portion 304 after incorporation has an enlarged diameter at the end. This part is a caulked part.

[0048] 2. Method of attaching the ferrule ring In this embodiment, first, the ferrule ring 301 is manufactured alone, and the manufactured ferrule ring 301 is attached to the small-diameter opening 133 of the dust cover 131. More specifically, the following steps are involved.

[0049] (1) Manufacture of the ferrule ring As shown in FIG. 6(A), the outer peripheral end of the ferrule ring 301 is bent, for example, at 30 degrees to form the inclined portion 303. Subsequently, the inner peripheral end of the ferrule ring 301 is bent at a right angle to form the cylindrical portion 304. The inclined portion 303 and the cylindrical portion 304 may be formed either successively or simultaneously.

[0050] (2) Fixation of the ferrule ring As shown in FIG. 6(B), the dust cover 131 and the ferrule ring 301 are faced so that the surface on the cylindrical portion 304 side of the ferrule ring 301 faces the small-diameter opening 133 of the dust cover 131. At this time, grease G is applied to the outer peripheral surface of the cylindrical portion 304 of the ferrule ring 301.

[0051] In this state, the cylindrical portion 304 is fitted into the opening portion of the small-diameter opening 133, and the ferrule ring 301 is attached to the dust cover 131. Then, the seal lip 141 provided in the small-diameter opening 133 comes into contact with the outer peripheral surface of the cylindrical portion 304, and the dust lip 151 abuts against the annular portion 302 of the ferrule ring 301.

[0052] FIG. 6(C) shows a state where the dust lip 151 provided in the small-diameter opening 133 abuts against the annular portion 302 of the ferrule ring 301. In this state, the jig 401 of a caulking machine (not shown) is pressed against the opening portion of the cylindrical portion 304, and a pressing force is applied as it is. The jig 401 is a pressing body having a cylindrical or cylindrical shape with an outer diameter dimension slightly larger than the inner diameter of the cylindrical portion 304, and the outer peripheral edge of the tip portion is formed in a curved surface shape so that it can enter the inner peripheral side of the cylindrical portion 304.

[0053] As shown in FIG. 6(D), when the jig 401 is pressed against the cylindrical portion 304 of the ferrule ring 301 to apply a pressing force, the end portion of the cylindrical portion 304 is pushed by the jig 401 and deformed. As a result, the small-diameter opening 133 of the dust cover 131 is caulked to the cylindrical portion 304 of the ferrule ring 301 (see FIG. 3). In FIG. 6(D), the caulked portion is indicated by reference numeral 305.

[0054] As shown in FIG. 1, the caulked portion 305 of the cylindrical portion 304 has an enlarged diameter, which matches the size and shape of the large-diameter portion 113a provided on the stud 113. Thereby, the ferrule ring 301 is fitted with the large-diameter portion 113a and the seal portion 113b of the stud 113.

[0055] (3) Comparative Example To compare with the attachment method of attaching the ferrule ring 301 of the present embodiment to the dust cover 131, three comparative examples are given.

[0056] (a) Comparative Example 1 The ferrule ring 301C1 of Comparative Example 1 is an example without the inclined portion 303. The annular portion 302 of the ferrule ring 301C1 has the portion of the inclined portion 303 of the present embodiment as a straight portion 311 (see FIG. 7(D)). The straight portion 311 is positioned on the same plane as the annular portion 302.

[0057] In other respects, regarding the manufacture of the ferrule ring 301C1 (see FIG. 7(A)) and the fixing of the ferrule ring 301C1 to the dust cover 131 (FIGS. 7(B) to (D)), they are the same as the manufacture and fixing of the ferrule ring 301 of the present embodiment (FIGS. 6(A), FIGS. 6(B) to (D)).

[0058] Considering that the ferrule ring 301C1 of Comparative Example 1 is specialized in not having the inclined portion 303, it has similarity with the configuration example described in Patent Document 1.

[0059] (b) Comparative Example 2 The ferrule ring 301C2 of Comparative Example 2 is an example in which the outer peripheral end of the ferrule ring 301C2 is bent at a right angle to form a bent portion 321 instead of the inclined portion 303 (see Fig. 8(D)). The ferrule ring 301C2 is provided with a bent portion 321 at the outer peripheral end which is the inclined portion 303 in the present embodiment, and the dust lip 151 of the dust cover 131 is brought into contact with the inner peripheral surface of the bent portion 321.

[0060] Regarding other points, regarding the manufacture of the ferrule ring 301C2 (see Fig. 8(A)) and the fixing of the ferrule ring 301C2 to the dust cover 131 (Figs. 8(B) to (D)), they are the same as the manufacture and fixing of the ferrule ring 301 of the present embodiment (Figs. 6(A), Figs. 6(B) to (D)).

[0061] Considering the ferrule ring 301C2 of Comparative Example 2 in particular, where the outer peripheral end of the annular portion 302 is bent and raised, and the dust lip 151 is brought into contact with the inner peripheral surface of this raised portion, it has similarity with the configuration example described in Patent Document 2.

[0062] (C) Comparative Example 3 The ferrule ring 301C3 of Comparative Example 3 is an example in which the outer peripheral end of the ferrule ring 301C3 is folded back to form a folded-back portion 331 instead of the inclined portion 303 (see Fig. 9(D)). The folded-back portion 331 is formed by bending the outer peripheral end of the ferrule ring 301C3 at an angle exceeding 90 degrees. The ferrule ring 301C3 is provided with a folded-back portion 331 at the outer peripheral end which is the inclined portion 303 in the present embodiment, and the dust lip 151 of the dust cover 131 is pressed in by the folded-back portion 331. As a result, the small-diameter opening 133 of the dust cover 131 is held so as to be wrapped by the ferrule ring 301C3.

[0063] The ferrule ring 301C3 of Comparative Example 3 differs from the ferrule ring 301 of the present embodiment, the ferrule ring 301C1 of Comparative Example 1, and the ferrule ring 301C2 of Comparative Example 2 in the method of attaching to the dust cover 131. The folded-back portion 331 is not created during the manufacturing stage of the ferrule ring 301C3 (see Fig. 9(A)). After fitting the cylindrical portion 304 of the ferrule ring 301C3 into the opening portion of the small-diameter opening 133 (see Figs. 9(B) and (C)), it is created before and after the caulking process using the jig 401.

[0064] Therefore, during the manufacturing stage of the ferrule ring 301C3, similar to the ferrule ring 301C1 of Comparative Example 1, no processing is performed to bend the outer peripheral end of the annular portion 302 (see Fig. 9(A)).

[0065] Considering that the ferrule ring 301C3 of Comparative Example 3 is specialized in holding so as to wrap around the small-diameter opening 133 of the dust cover 131, although the wrapping shape itself is different, it has similarity with the configuration example described in Patent Document 3.

[0066] The above three Comparative Examples 1 to 3 have been described. These Comparative Examples 1 to 3 illustrate what differences in operational effects there are between the ferrule ring 301 of the present embodiment when the inclined portion 303 is changed to the straight portion 311 (Comparative Example 1), the bent portion 321 (Comparative Example 2), and the folded-back portion 331 (Comparative Example 3), and how the ferrule ring 301 differs from the ferrule ring 301 in terms of the method of attaching to the dust cover 131. Regarding the outer peripheral end of the ferrule ring 301 (ferrule rings 301C1 to 3), although similarity is recognized with the structures described in Patent Document 1 for the straight portion 311, Patent Document 2 for the bent portion 321, and Patent Document 3 for the folded-back portion 331, Comparative Examples 1 to 3 are not prior art. They are merely comparative examples to be compared with the ferrule ring 301 of the present embodiment.

[0067] 3. Operational Effects (1) Basic Operational Effects In such a configuration, the seal lip 141 seals the seal portion 113b of the stud 113 via the cylindrical portion 304 of the ferrule ring 301. As a result, the seal lip 141 prevents the leakage of the lubricating grease accommodated in the space S defined by the film portion 132 of the dust cover 131, that is, inside the joint.

[0068] The knuckle 201 of the pinch bolt method adopted in the present embodiment allows the intrusion of external foreign matter into the notch 203. In the present embodiment, the external foreign matter that has entered from the notch 203 can be blocked by the ferrule ring 301, and it is possible to make it difficult for the stud 113 and the knuckle 201 to generate rust.

[0069] The ferrule ring 301 also has the effect of facilitating the provision of the dust lip 151 at the small-diameter opening 133 of the dust cover 131. The dust lip 151 contacts the lower surface 201U of the knuckle 201 via the annular portion 302 of the ferrule ring 301, and prevents the intrusion of external foreign matter such as water and dust into the joint.

[0070] In the environment where the ball joint 101 is used, an angular change occurs between a lower arm (not shown) that is a joint object and the knuckle 201. In response to this, the ball stud 111 swings or rotates, and the ball head portion 112 swings (arrow A in FIG. 1) or rotates (arrow B) in the socket 121 so that the ball head portion 112 can swing or rotate. The angular change between the two joint objects is absorbed by the movement of the ball head portion 112 in this way.

[0071] When the ball stud 111 swings, the dust cover 131 deforms. Since the dust cover 131 is a rubber-like elastic member, it has flexibility and elastic restoring force. When the ball stud 111 swings, the film portion 132 is stretched on the stretching side (the right side in FIG. 1), and the film portion 132 is bent and contracted on the contracting side (the left side in FIG. 1). The dust cover 131 absorbs the deformation accompanying the swing of the ball stud 111.

[0072] (2) Countermeasures against the mouth opening phenomenon When the ball stud 111 swings, the dust lip 151 provided at the small-diameter opening 133 on the extension side (corresponding to the right side in FIG. 1) may move away from the lower surface 201U of the knuckle 201. This is the so-called mouth-opening phenomenon.

[0073] The outer peripheral end of the ferrule ring 301C1 of Comparative Example 1 is a straight portion 311 that is continuous in the same plane as the annular portion 302 (see FIG. 7(D)). Therefore, when the mouth-opening phenomenon occurs, it allows the intrusion of external foreign matter from the gap generated between it and the small-diameter opening 133.

[0074] This is the same for the ferrule ring (referred to as "annular plate 6" in the same document) described in Patent Document 1.

[0075] When the mouth-opening phenomenon occurs in the ferrule ring 301 of the present embodiment, the inclined portion 303 covers the gap formed between it and the small-diameter opening 133. Therefore, according to the present embodiment, even if the mouth-opening phenomenon occurs, the intrusion of external foreign matter from the gap generated between the knuckle 201 and the small-diameter opening 133 is suppressed by the inclined portion 303, and the sealing function can be maintained.

[0076] (3) Suppression of increase in sliding torque The ferrule ring 301C2 of Comparative Example 2 has a bent portion 321 formed by bending the outer peripheral edge at a right angle, and the dust lip 151 of the small-diameter opening 133 is in contact with the inner peripheral surface of the bent portion 321 (see FIG. 8(D)). When the stud 113 swings and rotates, sliding occurs between the bent outer peripheral edge and the small-diameter opening 133 of the dust cover 131. The repeatedly occurring sliding promotes the wear of the small-diameter opening 133.

[0077] This is the same for the ferrule ring (referred to as "ferrule 9" in the same document) described in Patent Document 2.

[0078] In the present embodiment, instead of bending the outer peripheral edge of the ferrule ring 301 at a right angle, an inclined portion 303 is formed which is inclined toward the dust cover 131 at an obtuse angle with respect to the annular portion 302 on the inner peripheral side, thereby reducing the sliding torque between the dust cover 131 and the dust lip 151 provided at the small-diameter opening 133. Moreover, the lip end 151a on the outer peripheral side of the dust lip 151 is made smaller in diameter than the inclined portion 303, and the dust lip 151 is brought into contact with the ferrule ring 301 on the inner peripheral side of the inclined portion 303, so that no sliding torque is generated between the dust lip 151 and the inclined portion 303 (in the case of the above-described aspect 2), or even if it is generated, its reduction can be achieved (in the case of the above-described aspect 1). Therefore, wear of the small-diameter opening 133 can be suppressed and its durability can be improved.

[0079] (4) Prevention of increase in the number of manufacturing processes In the ferrule ring 301C3 of Comparative Example 3, the small-diameter opening 133 of the dust cover 131 is pressed in by the folding-back portion 331 and held so as to wrap around the small-diameter opening 133. For this reason, it is possible to suppress the opening phenomenon of the small-diameter opening 133. On the other hand, the folding-back portion 331 cannot be formed in advance on the ferrule ring 301C3. The folding-back portion 331 needs to be formed before and after the caulking portion 305 is formed by the jig 401 after the cylindrical portion 304 of the ferrule ring 301C3 is fitted into the opening portion of the small-diameter opening 133. Therefore, when manufacturing the ferrule ring 301C3, the folding-back portion 331 cannot be press-worked at the same time, and the number of manufacturing processes inevitably increases.

[0080] This also applies to the ferrule ring (the "ferrule ring 150" in the same document) described in Patent Document 3.

[0081] Regarding the number of manufacturing processes, consider the ferrule ring 301C1 of Comparative Example 1 which is not provided with a structure for suppressing the intrusion of external foreign matter due to the opening phenomenon such as the inclined portion 303 (present embodiment), the bending portion 321 (Comparative Example 2), and the folding-back portion 331 (Comparative Example 3) as a reference.

[0082] Although the ferrule ring 301C1 of Comparative Example 1 was described as having a straight portion 311 at its outer peripheral end, the straight portion 311 is not formed by any special processing and is merely the outer peripheral end of the annular portion 302. By forming the flat annular portion 302, its outer peripheral end naturally becomes the straight portion 311.

[0083] On the other hand, if the inclined portion 303 provided on the ferrule ring 301 of the present embodiment is integrally formed including the cylindrical portion 304 by pressing the ferrule ring 301, it can be formed by a single pressing process. Therefore, although an element (the inclined portion 303) that does not exist in Comparative Example 1 is provided, the number of manufacturing steps is the same as that of Comparative Example 1.

[0084] Alternatively, even when the inclined portion 303 is formed as a separate member from the annular portion 302, the ferrule ring 301 can be completed before being combined with the dust cover 131. Unlike the folded-back portion 331 of Comparative Example 3, processing after combination with the dust cover 131 is unnecessary. Therefore, there is no complexity of performing processing on the ferrule ring 301 after combination with the dust cover 131, and workability is improved.

[0085] [Second Embodiment] The second embodiment will be described with reference to FIGS. 10 and 11. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0086] As shown in FIG. 10, this embodiment is an example in which a dust lip 151 is not provided in the small-diameter opening 133 of the dust cover 131, and the metal reinforcing ring 161 is exposed. The rubber-like elastic material constituting the small-diameter opening 133 is provided so as to cover the inner peripheral side and the outer peripheral side of the reinforcing ring 161, respectively.

[0087] As shown in FIG. 11, the inclined portion 303 of the ferrule ring 301 is provided at a position that covers the small-diameter opening 133 of the dust cover 131 from the outer peripheral side and does not interfere with the small-diameter opening 133.

[0088] [Modification Example] During implementation, various modifications and changes are possible.

[0089] For example, when bending the ferrule ring 301 to form the inclined portion 303, the angle of bending the inclined portion 303 does not necessarily have to be 30 degrees. For example, it may be 5 degrees or more and less than 90 degrees. As a result, an inclined portion 303 that is obtusely inclined at an angle of 175 degrees or less toward the dust cover 131 side can be obtained with respect to the inner peripheral side surface of the ferrule ring 301. It is desirable that the angle of bending the inclined portion 303 is 5 degrees or more, in other words, the angle formed with the inner peripheral side surface of the ferrule ring 301 is 175 degrees or less, from the viewpoint of suppressing the so-called opening phenomenon when the stud 113 of the ball joint 101 swings, that is, the phenomenon that the small-diameter opening 133 of the dust lip 151 separates from the annular portion 302 of the ferrule ring 301 when foreign matter from the outside invades.

[0090] However, the inclined portion 303 does not necessarily have to be formed by bending the outer peripheral end of the ferrule ring 301. Another member constituting the inclined portion 303 may be joined to the outer peripheral edge of the ferrule ring 301. Also in this case, it is desirable that the inclined portion 303 is obtusely inclined at an angle of 175 degrees or less with respect to the inner peripheral side surface of the ferrule ring 301.

[0091] In the above-described embodiment, an example of the configuration in which the clamp 135 is embedded in the large-diameter opening 134 is shown, but the clamp 135 may be configured to tighten the large-diameter opening 134 from its outer peripheral side. Alternatively, the clamp 135 does not necessarily have to be provided.

[0092] In the above-described embodiment, an example in which two lip ends 151a are provided on the dust lip 151 is shown, but the number of lip ends 151a provided on the dust lip 151 does not have to be two, and may be, for example, one or three or more.

[0093] In the above embodiment, an example in which an L-shaped metal reinforcing ring 161 is embedded in the small-diameter opening 133 has been shown. However, the reinforcing ring 161 may be made of a material other than metal, for example, resin, etc., and may have a shape other than L-shape, for example, a rectangular cross-sectional shape, etc. The reinforcing ring 161 is not necessarily an essential element, and the small-diameter opening 133 may be configured without embedding the reinforcing ring 161.

[0094] In other implementations, all kinds of modifications and changes are allowed.

Explanation of reference numerals

[0095] 101 Ball joint 111 Ball stud 112 Ball head 113 Stud 113a Large-diameter portion 113b Seal portion 113c Mounting portion 121 Socket 122 Housing 123 Bearing 124 Base plate 125 Opening 126 Attachment portion 131 Dust cover 132 Membrane portion 133 Small-diameter opening 134 Large-diameter opening 135 Clamp 141 Seal lip 151 Dust lip 151a Lip end 161 Reinforcing ring 201 Knuckle 201U Lower surface 202 Mounting hole 203 Notch 204 Bolt hole 205 Bolt 206 Nut 207 Fastener 301 Ferrule ring 302 Annular portion 303 Tapered portion 304 Cylindrical part 305 Crimped part 311 Straight part 321 Bent part 331 Folded-back part A Swing direction B Rotation direction AX axis S Space

Claims

1. A seal structure for a ball joint in which a ferrule ring is interposed between a knuckle connected to a stud of the ball joint and a small-diameter opening of a dust cover covering the stud, wherein an outer peripheral end of the ferrule ring has an inclined portion that inclines toward the dust cover side at an obtuse angle with respect to a surface on the inner peripheral side of the ferrule ring, an annular reinforcing ring is embedded in the small-diameter opening of the dust cover, the reinforcing ring exposes a portion facing the ferrule ring from the small-diameter opening and contacts the ferrule ring, and has a smaller diameter than a minimum-diameter portion of the inclined portion of the ferrule ring, the inclined portion of the ferrule ring is provided at a position that covers the small-diameter opening from the outer peripheral side and does not interfere with the small-diameter opening, a seal structure for a ball joint.

2. A seal structure for a ball joint in which a ferrule ring is interposed between a knuckle connected to a stud of the ball joint and a small-diameter opening of a dust cover covering the stud, wherein an outer peripheral end of the ferrule ring has an inclined portion that inclines toward the dust cover side at an obtuse angle with respect to a surface on the inner peripheral side of the ferrule ring, an annular reinforcing ring is embedded in the small-diameter opening of the dust cover such that a portion facing the ferrule ring is exposed, the reinforcing ring contacts the ferrule ring on the inner peripheral side of a minimum-diameter portion of the inclined portion of the ferrule ring, the inclined portion of the ferrule ring is provided at a position that covers the small-diameter opening from the outer peripheral side and does not interfere with the small-diameter opening, a seal structure for a ball joint.

3. A ball joint that connects a knuckle to a stud and accommodates a ball head provided at an end of the stud in a socket so as to be swingable and rotatable, a dust cover including a large-diameter opening surrounding an accommodation region of the socket that houses the ball head and a small-diameter opening surrounding the stud, and connecting the large-diameter opening and the small-diameter opening with a film portion, a ferrule ring interposed between the knuckle and the small-diameter opening of the dust cover, comprising: the ferrule ring, has an annular portion that contacts one surface of the knuckle on the dust cover side, and an inclined portion provided on the outer peripheral side of the annular portion and inclining toward the dust cover side at an obtuse angle with respect to the annular portion, comprising: an annular reinforcing ring is embedded in the small-diameter opening of the dust cover, The reinforcing ring exposes the portion facing the ferrule ring from the small-diameter opening and contacts the ferrule ring, and has a diameter smaller than the minimum-diameter portion of the inclined portion of the ferrule ring. The inclined portion of the ferrule ring covers the small-diameter opening from the outer peripheral side and is provided at a position where it does not interfere with the small-diameter opening. Sealing structure of a ball joint.

4. A ball joint that connects a knuckle to a stud and accommodates a ball head provided at an end of the stud in a socket so as to be swingable and rotatable, A dust cover having a large-diameter opening surrounding an accommodation region of the socket that houses the ball head and a small-diameter opening surrounding the stud, and connecting the large-diameter opening and the small-diameter opening with a film portion, A ferrule ring interposed between the knuckle and the small-diameter opening of the dust cover, Comprising: The ferrule ring, An annular portion that contacts one surface of the knuckle on the dust cover side, An inclined portion provided on the outer peripheral side of the annular portion and inclined toward the dust cover side at an obtuse angle with respect to the annular portion, Comprising: An annular reinforcing ring is embedded in the small-diameter opening of the dust cover with a portion facing the ferrule ring exposed, The reinforcing ring contacts the ferrule ring on the inner peripheral side of the minimum-diameter portion of the inclined portion of the ferrule ring, The inclined portion of the ferrule ring covers the small-diameter opening from the outer peripheral side and is provided at a position where it does not interfere with the small-diameter opening. Sealing structure of a ball joint.

5. The rubber-like elastic material constituting the small-diameter opening is provided so as to cover the inner peripheral side and the outer peripheral side of the reinforcing ring. The sealing structure of the ball joint according to any one of Claims 1 to 4.

6. The reinforcing ring has an L-shaped cross section in which the inner peripheral side contacts the ferrule ring and the outer peripheral side faces the ferrule ring in a non-contact state. The sealing structure of the ball joint according to Claim 5.

7. The exposed portion of the reinforcing ring and the small-diameter opening are arranged in the same plane. The sealing structure of the ball joint according to Claim 5.

8. The ferrule ring has a cylindrical portion into which the stud fits, The small-diameter opening of the dust cover has a sealing lip that contacts the outer peripheral surface of the cylindrical portion at a portion covering the inner peripheral side of the reinforcing ring. The sealing structure of the ball joint according to any one of Claims 1 to 4.

9. The end of the cylindrical portion caulks the small-diameter opening of the dust cover. The seal structure of the ball joint according to claim 8.

10. The reinforcing ring is made of metal. The seal structure of the ball joint according to any one of claims 1 to 4.

11. The reinforcing ring is made of resin. The seal structure of the ball joint according to any one of claims 1 to 4.

12. The knuckle has a mounting hole through which the stud passes, a notch that communicates the mounting hole with the external space over the entire axial length, and a fixture that fixes the stud passing through the mounting hole by narrowing the interval between the notches. The seal structure of the ball joint according to any one of claims 1 to 4, comprising the above.

13. The inclined outer peripheral end of the ferrule ring is inclined at an angle of 5 degrees or more and less than 90 degrees. The seal structure of the ball joint according to any one of claims 1 to 4.

14. The ferrule ring is an integrally formed product. The seal structure of the ball joint according to any one of claims 1 to 4.

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