Ball joint

Abstract

To provide a ball joint enabling suppression of delay in the transmission of torque.SOLUTION: The ball joint comprises: a ball stud comprising a spherical head portion having a spherical surface; a bracket holding the spherical head portion in such a manner that the spherical head portion can be rotated; a ball which is located on a second axis line perpendicular to a first axis line being the axis line of the ball stud and passing through the center of the spherical head portion and transmits torque between the ball stud and the bracket. The spherical head portion includes a groove into which the ball is fitted.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a ball joint.

Background Art

[0002] When installing a vibration damping damper on a structure, a ball joint may be used. Patent Document 1 describes an example of a ball joint used in a vibration damping damper of a type that operates by torque transmission such as an inertial mass damper. The rotation restricting mechanism of the ball joint of Patent Document 1 includes an engagement hole formed in a spherical head and a restricting bolt inserted into the engagement hole. While the rocking of the spherical head is allowed by the restricting bolt, the rotation around the damper axis is restricted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the ball joint of Patent Document 1, it is necessary to provide a gap between the engagement hole and the restricting bolt. For this reason, a delay may occur when transmitting torque.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a ball joint capable of suppressing a delay in torque transmission.

Means for Solving the Problems

[0006] To achieve the above object, a ball joint according to one aspect of the present disclosure includes a ball stud having a spherical head with a spherical surface, a bracket that holds the spherical head so that the spherical head can rotate, and a ball that is located on a second axis that is orthogonal to a first axis that is the axis of the ball stud and passes through the center of the spherical head, and transmits torque between the ball stud and the bracket. The spherical head includes a groove into which the ball fits.

[0007] Thereby, it becomes possible to make the gap between the groove and the ball in the circumferential direction centered on the first axis infinitely small. Or, it becomes possible to eliminate the gap between the groove and the ball in the circumferential direction centered on the first axis. When there is no gap between the groove and the ball in the circumferential direction centered on the first axis, preload is applied to the ball. Thus, according to the ball joint, the gap between the groove and the ball in the circumferential direction centered on the first axis becomes small or disappears. Therefore, the ball joint can suppress or eliminate the delay in torque transmission.

[0008] As a desirable aspect of the ball joint, the bracket includes a hole that penetrates in a direction parallel to the second axis.

[0009] Thereby, it is possible to insert the ball into the groove through the hole. For this reason, the operation of arranging the ball in the groove becomes easy.

[0010] As a desirable aspect of the ball joint, the bracket includes a ball pressing member that is located inside the hole and contacts the ball.

[0011] Thereby, the movement of the ball in the direction parallel to the second axis is restricted. That is, the ball is positioned in the direction parallel to the second axis. For this reason, the dropout of the ball is suppressed.

[0012] As a desirable aspect of the ball joint, the ball pressing member includes a recess into which the ball fits, and in a cross-section orthogonal to the first axis and including the second axis, the surface of the recess depicts a third tangent line that is a tangent line to the ball and a fourth tangent line that is a tangent line to the ball and forms an angle with the third tangent line.

[0013] Thereby, even when the axis of the ball pressing member is displaced with respect to the second axis, a state where the ball is in line contact with the surface of the recess is maintained. For this reason, the gap between the recess and the ball in the circumferential direction centered on the first axis disappears. Therefore, the ball joint can eliminate the delay in torque transmission.

[0014] As a desirable aspect of the ball joint, the ball pressing member includes a recess into which the ball fits, and in a cross-section orthogonal to the first axis and including the second axis, the surface of the recess depicts an arc having a radius of curvature larger than the radius of the ball.

[0015] Thereby, even when the axis of the ball pressing member is displaced with respect to the second axis, a state where the ball contacts the surface of the recess at one point is maintained. For this reason, the gap between the recess and the ball in the circumferential direction centered on the first axis becomes smaller or disappears. Therefore, the ball joint can suppress the delay in torque transmission or eliminate the delay in torque transmission.

[0016] As a desirable aspect of the ball joint, in a cross-section including the first axis and the second axis, the surface of the groove depicts an arc centered on the center of the spherical head.

[0017] Thereby, the relative rotation between the ball stud and the bracket around a straight line orthogonal to both the first axis and the second axis becomes smooth. For this reason, the ball joint can suppress vibration.

[0018] In a preferred embodiment of the ball joint, in a cross section perpendicular to the first axis and including the second axis, the surface of the groove describes an arc having a radius of curvature that is equal to or smaller than the radius of the ball.

[0019] This makes it easier to restrict the movement of the ball around the first axis, thereby suppressing fluctuations in the size of the gap between the groove and the ball in the circumferential direction around the first axis, making it easier for the ball joint to suppress delays in torque transmission.

[0020] In a preferred embodiment of the ball joint, in a cross section perpendicular to the first axis and including the second axis, the surface of the groove describes a first tangent that is a tangent to the ball, and a second tangent that is a tangent to the ball and forms an angle with the first tangent.

[0021] This ensures that the ball remains in contact with the surface of the groove at two points, even if the axis of the ball retainer member is misaligned with the second axis. This eliminates any gap between the groove and the ball in the circumferential direction around the first axis. As a result, the ball joint can eliminate delays in torque transmission.

[0022] In a preferred embodiment of the ball joint, in a cross section perpendicular to the first axis and including the second axis, the surface of the groove describes an arc having a radius of curvature larger than the radius of the ball.

[0023] This allows the ball to maintain single-point contact with the surface of the groove even if the axis of the ball-pressing member deviates from the second axis. This reduces or eliminates the gap between the groove and the ball in the circumferential direction centered on the first axis A1. Therefore, the ball joint can reduce or eliminate delays in torque transmission. [Effects of the Invention]

[0024] According to the ball joint of the present disclosure, delay in torque transmission can be suppressed.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0026] Hereinafter, the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the following embodiments for carrying out the invention (hereinafter referred to as embodiments). In addition, the constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those within the so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be combined as appropriate.

[0027] Figure 1 is a front view of the ball joint of the present embodiment. Figure 2 is a sectional view taken along line A-A of Figure 1. Figure 3 is an enlarged view of Figure 2. Figure 4 is a sectional view taken along line B-B of Figure 1. Figure 5 is an enlarged view of Figure 4.

[0028] The ball joint 1 of the present embodiment is used, for example, as a member for supporting a vibration damping damper. The vibration damping damper is, for example, an inertial mass damper and is a damper that operates when torque is transmitted.

[0029] As shown in FIGS. 1 and 2, the ball joint 1 includes a ball stud 3, a bracket 5, and two balls 9.

[0030] As shown in FIG. 2, the ball stud 3 includes a rod 31 and a spherical head 32. The rod 31 is a substantially cylindrical member. The rod 31 is fixed to, for example, a vibration damping damper. The spherical head 32 is located at the tip of the rod 31. The surface of the spherical head 32 is spherical. The center C32 of the spherical head 32 is located on a first axis A1 that is the axis of the ball stud 3. The first axis A1 is a straight line passing through the centroid of each cross-section obtained by cutting the rod 31 with a plane orthogonal to the longitudinal direction. As shown in FIG. 2, a second axis A2 is a straight line orthogonal to the first axis A1 and passing through the center C32 of the spherical head 32. The second axis A2 is a straight line passing through the center C32 of the spherical head 32 and the ball 9.

[0031] In the following description, an XYZ orthogonal coordinate system is used. The X-axis is parallel to the first axis A1. The Y-axis is parallel to the second axis A2. The Z-axis is orthogonal to both the first axis A1 and the second axis A2. A direction parallel to the X-axis is described as the X direction. A direction parallel to the Y-axis is described as the Y direction. A direction parallel to the Z-axis is described as the Z direction.

[0032] As shown in FIG. 2, the spherical head 32 includes two grooves 321. The grooves 321 are oval when viewed from the Y direction as shown in FIG. 1. The longitudinal direction of the grooves 321 when viewed from the Y direction is parallel to the first axis A1.

[0033] Figures 2 and 3 are cross-sections including the first axis A1 and the second axis A2. Figures 4 and 5 are cross-sections orthogonal to the first axis A1 and including the second axis A2. In the cross-sections of Figures 2 and 3, the surface of the groove 321 depicts an arc E1 centered on the center C32 of the spherical head 32. That is, in the cross-sections of Figures 2 and 3, the distance D321 (see Figure 2) from the center C32 of the spherical head 32 to the surface of the groove 321 is constant.

[0034] In the cross-sections of Figures 4 and 5, the surface of the groove 321 depicts an arc E2 centered on a point on the side of the center C9 of the ball 9. The radius of curvature RE2 of the arc E2 depicted by the surface of the groove 321 is equal to or less than the radius R9 of the ball 9. That is, in the cross-sections of Figures 4 and 5, the curvature of the arc E2 depicted by the surface of the groove 321 is equal to or greater than the curvature of the surface of the ball 9. For example, in the present embodiment, the radius of curvature RE2 is equal to the radius R9 of the ball 9. That is, in the cross-sections of Figures 4 and 5, the curvature of the arc E2 depicted by the surface of the groove 321 is equal to the curvature of the surface of the ball 9.

[0035] As shown in Figure 2, the bracket 5 is a cylindrical member that holds the spherical head 32. The bracket 5 supports the spherical head 32 so that the spherical head 32 can rotate. At least a part of the inner peripheral surface of the bracket 5 is in contact with the surface of the spherical head 32. The bracket 5 is fixed to a structure to which, for example, a vibration damping damper is attached. As shown in Figure 2, the bracket 5 includes a holder 55, two holes 51, and two ball pressing members 53. As shown in Figure 2, the holder 55 is arranged on the inner peripheral surface of the bracket 5 and is a member that supports the spherical head 32.

[0036] As shown in Figure 2, the holes 51 penetrate the bracket 5 in the Y direction. The two holes 51 are located on the second axis A2. One hole 51 overlaps the other hole 51 when viewed from the Y direction. The holes 51 are cylindrical. That is, as shown in Figure 1, the holes 51 are circular when viewed from the Y direction. When viewed from the Y direction, the center of the hole 51 overlaps the center C32 of the spherical head 32. The diameter of the hole 51 is equal to or larger than the diameter of the ball 9.

[0037] As shown in FIG. 2, the ball pressing member 53 is disposed inside the hole 51. The ball pressing member 53 contacts the ball 9. The ball pressing member 53 is, for example, a columnar metal member equal in diameter to the hole 51 and is press-fitted into the hole 51. Thereby, it becomes difficult for the ball pressing member 53 to come out of the hole 51. The ball pressing member 53 may be an elastic member such as rubber and synthetic resin. As shown in FIG. 2, the ball pressing member 53 does not protrude from the outer surface of the bracket 5. That is, the outer end portion of the ball pressing member 53 in the Y direction is located closer to the center C32 of the spherical head portion 32 than the outer surface of the bracket 5.

[0038] The ball 9 is a spherical member. As shown in FIGS. 2 and 4, the ball 9 is located on the second axis A2. The ball 9 is located at the boundary between the spherical head portion 32 of the ball stud 3 and the bracket 5. At least a part of the ball 9 overlaps the boundary line between the spherical head portion 32 of the ball stud 3 and the bracket 5. For example, in the present embodiment, as shown in FIG. 3, the center of the ball 9 overlaps the boundary line between the spherical head portion 32 of the ball stud 3 and the bracket 5.

[0039] The ball 9 contacts the ball stud 3 and the bracket 5. The ball 9 transmits the torque between the ball stud 3 and the bracket 5. For example, the length of the groove 321 in the Z direction is equal to the diameter of the ball 9. By the ball 9, the relative rotation of the ball stud 3 and the bracket 5 about the X axis is restricted. Therefore, when torque about the X axis is input to the ball stud 3 or the bracket 5, the ball stud 3, the bracket 5, and the ball 9 rotate integrally about the X axis.

[0040] As shown in FIG. 2, the length of the groove 321 in the X direction is larger than the diameter of the ball 9. Therefore, the ball stud 3 and the bracket 5 can rotate relative to each other about the Z axis. Also, the ball stud 3 and the bracket 5 can rotate relative to each other about the Y axis. That is, between the ball stud 3 and the bracket 5, torque about the X axis is transmitted, while torque about the Y axis and torque about the Z axis are not transmitted.

[0041] As described above, the vibration damping damper to which the ball joint 1 is applied is, for example, an inertial mass damper. The inertial mass damper is a device that converts an input axial external force into rotational energy. The ball joint 1 and the vibration damping damper are connected such that the X-axis is parallel to the axis of the vibration damping damper.

[0042] The ball joint 1 transmits torque about the X-axis. Therefore, the rotation about the axis of the vibration damping damper is transmitted to the structure to which the vibration damping damper is attached via the ball joint 1. On the other hand, the ball joint 1 does not transmit torque about the Y-axis and torque about the Z-axis. Therefore, when the vibration damping damper rotates (swings) such that the axis of the vibration damping damper forms an angle with respect to the X-axis, the rotation (swing) of the vibration damping damper is not transmitted to the structure.

[0043] Note that the ball joint 1 does not necessarily have to be used as a member for supporting the vibration damping damper. The object to which the ball joint 1 is connected is not particularly limited. The ball joint 1 can be widely used as a device for connecting two relatively rotatable members.

[0044] The ball joint 1 does not necessarily have to include two balls 9. The ball joint 1 only needs to include at least one ball 9. The spherical head 32 only needs to include at least one groove 321.

[0045] As described above, the ball joint 1 includes a ball stud 3, a bracket 5, and a ball 9. The ball stud 3 includes a spherical head 32 having a spherical surface. The bracket 5 holds the spherical head 32 such that the spherical head 32 can rotate. The ball 9 is located on a second axis A2 that is orthogonal to the first axis A1, which is the axis of the ball stud 3, and passes through the center C32 of the spherical head 32, and transmits torque between the ball stud 3 and the bracket 5. The spherical head 32 includes a groove 321 into which the ball 9 fits.

[0046] This makes it possible to minimize the gap between the groove 321 and the ball 9 in the circumferential direction about the first axis A1. Alternatively, it is possible to eliminate the gap between the groove 321 and the ball 9 in the circumferential direction about the first axis A1. If there is no gap between the groove 321 and the ball 9 in the circumferential direction about the first axis A1, a preload will be applied to the ball 9. In this way, according to the ball joint 1, the gap between the groove 321 and the ball 9 in the circumferential direction about the first axis A1 is reduced or eliminated. Therefore, the ball joint 1 can suppress or eliminate delays in torque transmission.

[0047] In the ball joint 1, in a cross section including the first axis A1 and the second axis A2, the surface of the groove 321 describes an arc E1 centered on the center C32 of the spherical head 32.

[0048] This allows smooth relative rotation between the ball stud 3 and the bracket 5 around a straight line perpendicular to both the first axis A1 and the second axis A2, thereby enabling the ball joint 1 to suppress vibration.

[0049] In the ball joint 1, in a cross section perpendicular to the first axis A1 and including the second axis A2, the surface of the groove 321 describes an arc E2 having a radius of curvature RE2 that is equal to or smaller than the radius R9 of the ball 9.

[0050] This makes it easier to restrict the movement of the ball 9 around the first axis A1, thereby suppressing fluctuations in the size of the gap between the groove 321 and the ball 9 in the circumferential direction around the first axis A1. Therefore, the ball joint 1 can more easily suppress delays in torque transmission.

[0051] In the ball joint 1, the bracket 5 has a hole 51 that penetrates in a direction parallel to the second axis A2.

[0052] As a result, the ball 9 can be inserted into the groove 321 through the hole 51. Therefore, the operation of arranging the ball 9 in the groove 321 becomes easy.

[0053] In the ball joint 1, the bracket 5 includes a ball pressing member 53 that is located inside the hole 51 and contacts the ball 9.

[0054] As a result, the movement of the ball 9 in the direction parallel to the second axis A2 is restricted. That is, the ball 9 is positioned in the direction parallel to the second axis A2. Therefore, the dropout of the ball 9 is suppressed.

[0055] (First Modification Example) FIG. 6 is a cross-sectional view corresponding to the A-A cross-sectional view of FIG. 1 in the first modification example. FIG. 6 is a cross-section including the first axis A1 and the second axis A2. FIG. 7 is a cross-sectional view corresponding to the B-B cross-sectional view of FIG. 1 in the first modification example. FIG. 7 is a cross-section orthogonal to the first axis A1 and including the second axis A2. Note that the same components as those described in the above-described embodiment are denoted by the same reference numerals, and redundant descriptions are omitted.

[0056] As shown in FIGS. 6 and 7, the spherical head 32A of the first modification example includes a groove 321A. In the cross-section of FIG. 7, the surface of the groove 321A depicts a substantially V shape. In the cross-section of FIG. 7, the surface of the groove 321A depicts a first tangent line F1 that is a tangent line to the ball 9 and a second tangent line F2 that is a tangent line to the ball 9 and forms an angle with the first tangent line F1. The second tangent line F2 is symmetric with the first tangent line F1 with the second axis A2 as the axis of symmetry. The ball 9 contacts the surface of the groove 321A at two points.

[0057] As shown in FIGS. 6 and 7, the bracket 5A of the first modification includes a ball pressing member 53A. The ball pressing member 53A is arranged with a gap with respect to the spherical head 32A. The ball pressing member 53A includes a recess 531A into which the ball 9 fits. The recess 531A is conical. In the cross-section of FIG. 7, the surface of the recess 531A depicts a third tangent line F3 that is a tangent line to the ball 9 and a fourth tangent line F4 that is a tangent line to the ball 9 and forms an angle with the third tangent line F4. The fourth tangent line F4 is symmetric with the third tangent line F3 with the second axis A2 as the axis of symmetry. The ball 9 is in line contact with the surface of the recess 531A.

[0058] FIG. 8 is a cross-sectional view when the axis of the ball pressing member 53A is displaced with respect to the second axis. As shown in FIG. 8, due to machining errors or the like, the axis A3 of the ball pressing member 53A may be displaced with respect to the second axis A2. The displacement of the axis A3 with respect to the second axis A2 means that the axis A3 is displaced in the X direction or the Z direction with respect to the second axis A2, or the axis A3 forms an angle with the second axis A2. In the ball joint 1A of the first modification, even when the axis A3 of the ball pressing member 53A is displaced with respect to the second axis A2, the state in which the ball 9 is in two-point contact with the surface of the groove 321A and in line contact with the surface of the recess 531A is maintained.

[0059] Note that the shape of the groove 321A is not limited to the shape described above. The surface of the groove 321A does not have to depict a substantially V shape in the cross-section of FIG. 7. For example, the surface of the groove 321A may depict a substantially U shape in the cross-section of FIG. 7. The shape of the recess 531A of the ball pressing member 53A is not limited to the shape described above. The recess 531A does not have to be conical. For example, the recess 531A may be frustoconical.

[0060] As described above, in a cross-section orthogonal to the first axis A1 and including the second axis A2, the surface of the groove 321A depicts a first tangent line F1 that is a tangent line to the ball 9 and a second tangent line F2 that is a tangent line to the ball 9 and forms an angle with the first tangent line F1.

[0061] As a result, even when the axis A3 of the ball pressing member 53A is displaced relative to the second axis A2, the state where the ball 9 is in contact with the surface of the groove 321A at two points is maintained. For this reason, the gap between the groove 321A and the ball 9 in the circumferential direction centered on the first axis A1 disappears. Therefore, the ball joint 1A can eliminate the delay in torque transmission.

[0062] In the ball joint 1A, the ball pressing member 53A includes a recess 531A into which the ball 9 fits. In a cross-section orthogonal to the first axis A1 and including the second axis A2, the surface of the recess 531A depicts a third tangent line F3 that is a tangent line to the ball 9 and a fourth tangent line F4 that is a tangent line to the ball 9 and forms an angle with the third tangent line F3.

[0063] As a result, even when the axis A3 of the ball pressing member 53A is displaced relative to the second axis A2, the state where the ball 9 is in line contact with the surface of the recess 531A is maintained. For this reason, the gap between the recess 531A and the ball 9 in the circumferential direction centered on the first axis A1 disappears. Therefore, the ball joint 1A can eliminate the delay in torque transmission.

[0064] (Second Modification Example) FIG. 9 is a cross-sectional view corresponding to the B-B cross-sectional view of FIG. 1 in the second modification example. FIG. 9 is a cross-section orthogonal to the first axis A1 and including the second axis A2. Note that the same reference numerals are given to the same components as those described in the above-described embodiment, and redundant descriptions are omitted.

[0065] As shown in FIG. 9, the spherical head 32B of the second modification example includes a groove 321B. In the cross-section of FIG. 9, the surface of the groove 321B depicts an arc G1. The radius of curvature RG1 of the arc G1 is larger than the radius R9 of the ball 9. That is, in the cross-section of FIG. 9, the curvature of the arc G1 depicted by the surface of the groove 321B is smaller than the curvature of the surface of the ball 9. The ball 9 is in contact with the surface of the groove 321B at one point.

[0066] As shown in Fig. 9, the bracket 5B of the second modification includes a ball pressing member 53B. The ball pressing member 53B includes a recess 531B into which the ball 9 fits. The recess 531B is hemispherical. In the cross-section of Fig. 9, the surface of the recess 531B describes an arc G2. The radius of curvature RG2 of the arc G2 is larger than the radius R9 of the ball 9. That is, in the cross-section of Fig. 9, the curvature of the arc G2 described by the surface of the recess 531B is smaller than the curvature of the surface of the ball 9. The ball 9 contacts the surface of the recess 531B at one point.

[0067] Fig. 10 is a cross-sectional view when the axis of the ball pressing member is displaced with respect to the second axis. As shown in Fig. 10, due to machining errors or the like, the axis A3 of the ball pressing member 53B may be displaced with respect to the second axis A2. In the ball joint 1B of the second modification, even when the axis A3 of the ball pressing member 53B is displaced with respect to the second axis A2, the state in which the ball 9 contacts the surface of the groove 321B at one point and contacts the surface of the recess 531B at one point is maintained.

[0068] As described above, in a cross-section orthogonal to the first axis A1 and including the second axis A2, the surface of the groove 321B describes an arc G1 having a radius of curvature RG1 larger than the radius R9 of the ball 9.

[0069] Thereby, even when the axis A3 of the ball pressing member 53A is displaced with respect to the second axis A2, the state in which the ball 9 contacts the surface of the groove 321B at one point is maintained. For this reason, the gap between the groove 321B and the ball 9 in the circumferential direction centered on the first axis A1 becomes smaller or disappears. Therefore, the ball joint 1B can suppress or eliminate the delay in torque transmission.

[0070] In the ball joint 1B, the ball pressing member 53B includes a recess 531B into which the ball 9 fits. In a cross-section orthogonal to the first axis A1 and including the second axis A2, the surface of the recess 531B describes an arc G2 having a radius of curvature RG2 larger than the radius R9 of the ball 9.

[0071] Thus, even when the axis A3 of the ball pressing member 53B is displaced with respect to the second axis A2, the ball 9 is maintained in a state of contacting the surface of the recess 531B at a single point. For this reason, the gap between the recess 531B and the ball 9 in the circumferential direction centered on the first axis A1 becomes smaller or disappears. Therefore, the ball joint 1B can suppress or eliminate the delay in torque transmission.

Explanation of Reference Numerals

[0072] 1, 1A, 1B Ball joint 3 Ball stud 31 Rod 32, 32A, 32B Spherical head 321, 321A, 321B Groove 5, 5A, 5B Bracket 51 Hole 53, 53A, 53B Ball pressing member 531A, 531B Recess 55 Holder 9 Ball A1 First axis A2 Second axis C32, C9 Center D321 Distance E1, E2 Arc F1 First tangent F2 Second tangent F3 Third tangent F4 Fourth tangent G1, G2 Arc R9 Radius RE2, RG1, RG2 Radius of curvature

Claims

1. A ball stud having a spherical head with a spherical surface, a bracket that holds the spherical head so that the spherical head can rotate, a ball located on a second axis that is orthogonal to a first axis which is the axis of the ball stud and passes through the center of the spherical head, and transmits torque between the ball stud and the bracket, comprising: the spherical head includes a groove into which the ball fits a ball joint.

2. The bracket according to claim 1, wherein the bracket includes a hole penetrating in a direction parallel to the second axis a ball joint according to claim 1.

3. The bracket according to claim 2, wherein the bracket includes a ball pressing member located inside the hole and in contact with the ball a ball joint according to claim 2.

4. The ball pressing member includes a recess into which the ball fits, in a cross-section orthogonal to the first axis and including the second axis, the surface of the recess depicts a third tangent that is a tangent to the ball and a fourth tangent that is a tangent to the ball and forms an angle with the third tangent a ball joint according to claim 3.

5. The ball pressing member includes a recess into which the ball fits, in a cross-section orthogonal to the first axis and including the second axis, the surface of the recess depicts an arc having a radius of curvature larger than the radius of the ball a ball joint according to claim 3.

6. In a cross-section including the first axis and the second axis, the surface of the groove depicts an arc centered on the center of the spherical head a ball joint according to any one of claims 1 to 5.

7. In a cross-section orthogonal to the first axis and including the second axis, the surface of the groove depicts an arc having a radius of curvature equal to or less than the radius of the ball a ball joint according to any one of claims 1 to 5.

8. In a cross-section orthogonal to the first axis and including the second axis, the surface of the groove depicts a first tangent that is a tangent to the ball and a second tangent that is a tangent to the ball and forms an angle with the first tangent a ball joint according to any one of claims 1 to 5.

9. In a cross-section orthogonal to the first axis and including the second axis, the surface of the groove depicts an arc having a radius of curvature larger than the radius of the ball a ball joint according to any one of claims 1 to 5.

Images