Automatic ball assembling method of constant velocity universal joint

Abstract

An automatic ball assembly method for a constant velocity universal joint (1, 201) is characterized in that: an inner assembly (I) in which a spherical outer peripheral surface (8, 208) of an inner joint member (3, 203) is fitted to a spherical inner peripheral surface (13, 213) of a holder (5, 205) is fitted to a spherical inner peripheral surface (6, 206) of an outer joint member (2, 202); the cage (5, 205), the inner joint member (3, 203), and the outer joint member (2, 202) are disposed in a state in which the axes of the cage (5, 205), the inner joint member (3, 203), and the outer joint member (2, 202) substantially coincide with each other, the axis of the inner joint member (3, 203) is tilted with respect to the axis of the outer joint member (2, 202) by means of a tilt bar (61), balls (4, 204) are assembled to pockets (5a, 205a) of the cage (5, 205) exposed at the open end of the outer joint member (2, 202), and then the balls (4, 204) are attached to the pockets (5a, 205a). In order to assemble the balls (4, 204) to other pockets (5a, 205a) of the retainers (5, 205), the retainers (5, 205) are pressed by a retainer press-fitting mechanism (65) when the axis of the inner joint member (3, 203) is tilted and returned by a tilt lever (61).

Description

Technical Field

[0001] The present invention relates to a method for automatically assembling balls of a constant velocity universal joint. Background Art

[0002] The present invention relates to a method for automatically assembling balls of a constant velocity universal joint, which constant velocity universal joint includes: an outer joint member having a plurality of race grooves extending in the axial direction formed on a spherical inner peripheral surface, and having an open side and an inner side separated in the axial direction; an inner joint member having a plurality of race grooves extending in the axial direction formed on a spherical outer peripheral surface; a plurality of balls disposed between the race grooves of the outer joint member and the corresponding race grooves of the inner joint member to transmit torque; and a cage having recessed pockets for receiving the balls, and having a spherical outer peripheral surface and a spherical inner peripheral surface that are respectively in sliding contact with the spherical inner peripheral surface of the outer joint member and the spherical outer peripheral surface of the inner joint member.

[0003] As an example of such a constant velocity universal joint, there is a constant velocity universal joint in which the race grooves of the outer joint member and the inner joint member have an arc-shaped ball track center line, the ball track center line has a curvature center that is not offset axially with respect to the joint center, the plane including the ball track center line and the joint center is inclined circumferentially with respect to the axis of the joint, and the inclination direction is opposite between the race grooves of the outer joint member and the race grooves of the inner joint member. Further, in a constant velocity universal joint in which the inclination directions of the race grooves of the outer joint member and the inner joint member are alternately opposite in the circumferential direction, torque loss and heat generation are small, and high efficiency can be achieved.

[0004] As a conventional assembling method, Patent Document 1 describes an automatic assembling method for a ball cage type constant velocity universal joint using six balls. The automatic assembling method includes a reference ball insertion step, an inner assembly assembling step, and a ball assembling step. Specifically, in the reference ball insertion step, after aligning the race groove of the inner ring with the recessed pocket of the cage with respect to the inner ring and the inner assembly in which the cage is fitted on the outside thereof, a reference ball is inserted into one recessed pocket. Next, in the inner assembly assembling step, with the reference ball in one recessed pocket located outside the outer ring, the recessed pockets formed on both sides of the axis of the cage sandwiching the cage are aligned with the protrusions at the opposing positions formed between the race grooves of the outer ring, and the inner assembly is fitted and inserted into the inside of the outer ring, and assembled in such a manner that their axes are orthogonal to each other. Then, after rotating the inner assembly by a certain angle in the circumferential direction of the outer ring, the inner assembly is inverted into the outer ring in a coaxial state with the outer ring, and the reference ball is fitted into a pair of race grooves of the inner ring and the outer ring.

[0005] Further, an automatic assembly method is proposed, which is characterized in that, in the ball assembly process, with the reference ball fitted into the raceway groove, the inner assembly is tilted relative to the outer ring, whereby the recessed pockets in a 120° positional relationship with respect to the reference ball in the phase direction are exposed from the open end of the outer ring. Then, balls are inserted into the exposed recessed pockets, and then the inner assembly is restored to fit the balls into the corresponding raceway grooves of the outer ring. For each of the remaining recessed pockets, balls are inserted in sequence while tilting the inner assembly.

[0006] Prior art documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 62-37519 Summary of the invention

[0009] Problems to be solved by the invention

[0010] Patent Document 1 is premised on the assembly of a constant velocity joint of the ball cage type. The constant velocity joint of the ball cage type uses six balls in which the raceway grooves of the inner coupling member and the outer coupling member are not inclined in the circumferential direction and the plane containing the center line of the ball track including the raceway groove and the center of the coupling is in the same direction as the axis of the coupling. Therefore, after the balls are inserted into the recessed pockets of the cage, when the inner assembly composed of the cage and the inner coupling member is restored to fit the balls into the corresponding raceway grooves of the outer ring, the inner assembly tilts relatively smoothly, and automatic assembly of the constant velocity joint can be performed.

[0011] However, in the case of a constant velocity joint with a tolerance raceway groove form in which the plane containing the center line of the ball track including the raceway groove and the center of the coupling is inclined in the circumferential direction with respect to the axis of the coupling, it has been found that the following problem of poor ball assembly occurs during the development of automatic ball assembly. This problem will be described with reference to FIG. 19. Figure 19A , Figure 19C is a perspective view observed from the plane direction, Figure 19B , Figure 19D is a perspective view observed from the front direction.

[0012] As Figure 19A , Figure 16 shown in B, after the balls 4 are inserted into the recessed pockets 5a of the cage 5, when the inclination of the inner assembly I composed of the inner coupling member 3 and the cage 5 is to be returned, as Figure 19C , Figure 19D shown, the cage 5 stays as it is, only the inner coupling member 3 tilts, and the balls 4 are pressed by the shoulders of the raceway grooves 7 of the inner coupling member 3, and the phase of the balls 4 is shifted. As a result, as Figure 19CAs shown, the ball 4 interferes with the shoulder K of the raceway groove 7 of the outer coupling member 2, and the ball 4 is jammed without entering the raceway groove 7 of the outer coupling member 2. Also, it was found that the inner assembly I could not return to the horizontal state, and there was a problem of poor ball assembly during the automatic ball assembly of the constant velocity universal joint 1 with a tolerance raceway groove type.

[0013] In addition, although not shown in the drawings, in a ball cage type constant velocity universal joint, in order to achieve light weight and compactness, for example, in the case of an internal specification with a reduced amount of raceway offset, it was also found that problems such as the occurrence of the same poor ball assembly and the stable tilting of the inner assembly could not be obtained.

[0014] In view of the above problems, an object of the present invention is to provide a method for automatically assembling balls of a constant velocity universal joint, which can achieve automatic ball assembly regardless of the raceway groove form such as a constant velocity universal joint with a cross raceway groove form or the internal specifications such as a ball cage type constant velocity universal joint.

[0015] Means for Solving the Problem

[0016] The inventors of the present invention conducted various studies to achieve the above object, and as a result, came up with the idea of operating the cage pressing mechanism simultaneously with the tilting return operation of the tilting rod when returning the tilt of the inner assembly in which a part of the balls are assembled, thereby completing the present invention.

[0017] As a technical solution for achieving the above object, the present invention relates to a method for automatically assembling balls of a constant velocity universal joint. The constant velocity universal joint includes: an outer joint member having a plurality of raceway grooves extending in the axial direction formed on a spherical inner peripheral surface, and having an open side and an inner side separated in the axial direction; an inner joint member having a plurality of raceway grooves extending in the axial direction formed on a spherical outer peripheral surface; a plurality of balls disposed between the raceway grooves of the outer joint member and the corresponding raceway grooves of the inner joint member to transmit torque; and a cage having pockets for receiving the balls, and having a spherical outer peripheral surface and a spherical inner peripheral surface that respectively slide in contact with the spherical inner peripheral surface of the outer joint member and the spherical outer peripheral surface of the inner joint member. The method is characterized in that an inner assembly obtained by fitting the spherical outer peripheral surface of the inner joint member into the spherical inner peripheral surface of the cage is fitted into the spherical inner peripheral surface of the outer joint member, and the cage, the inner joint member, and the outer joint member are arranged in a state where their respective axes are substantially aligned. Then, the axis of the inner joint member is inclined relative to the axis of the outer joint member by using an inclined rod, and the balls are assembled into the pockets of the cage exposed at the open end of the outer joint member. Subsequently, in order to assemble the balls into other pockets of the cage, when the inclination of the axis of the inner joint member is returned by using the inclined rod, the cage is pressed in by using a cage pressing mechanism. According to the above structure, regardless of the groove form of a constant velocity universal joint with a crossed raceway groove form or the internal specifications of a ball cage type constant velocity universal joint, etc., a method for automatically assembling balls of a constant velocity universal joint capable of automatically assembling balls can be achieved.

[0018] Specifically, when the axis of the inner joint member is inclined relative to the axis of the outer joint member by using the above inclined rod, the cage can be pressed in by using a cage erecting rod. Thereby, the inner joint member in a horizontal posture can be reliably inclined, thus promoting the ball automatic assembly method.

[0019] Preferably, the above cage pressing mechanism is driven by a drive source different from the drive source of the inclined rod. Thereby, the advancing end of the cage pressing rod of the cage pressing mechanism can be reliably defined.

[0020] The above cage pressing mechanism can be attached to the inclined rod and driven by the drive source of the inclined rod. Thereby, the cage pressing mechanism can be simplified and can be configured at low cost.

[0021] The characteristics of the automatic ball assembling method for the constant velocity universal joint of the present invention are as follows. The above constant velocity universal joint is in the form of a cross-raceway groove. In the raceway groove of the outer joint member, the center line of the ball track has an arc-shaped part with the center of the joint (O) as the center of curvature. The plane (M) containing the center line of the ball track and the center of the joint (O) is inclined with respect to the axis (N-N) of the joint, and the inclination directions of the raceway grooves adjacent in the circumferential direction are opposite to each other. The center line of the ball track of the raceway groove of the inner joint member is mirror-symmetrical with the center lines of the ball tracks of the paired raceway grooves of the outer joint member with respect to the plane (P) which contains the center of the joint (O) and is orthogonal to the axis (N-N) of the joint in the state where the working angle is 0°. Thus, an automatic ball assembling method for a high-efficiency cross-raceway groove type constant velocity universal joint can be realized.

[0022] The characteristics of the automatic ball assembling method for the constant velocity universal joint of the present invention are as follows. The raceway groove of the outer joint member of the above constant velocity universal joint is composed of a first raceway groove part (7a) located on the inner side and a second raceway groove part (7b) located on the opening side. The first raceway groove part (7a) has an arc-shaped center line (Xa) of the ball track with the center of the joint (O) as the center of curvature. The plane (M) containing at least the center line (Xa) of the ball track and the center of the joint (O) is inclined with respect to the axis (N-N) of the joint, and the inclination directions of the adjacent first raceway groove parts (7a) in the circumferential direction are opposite to each other. When the center line (Xb) of the ball track of the second raceway groove part (7b) is projected onto the plane (M), the center line (Xb) of the ball track has a straight part, and this straight part is formed to be inclined in a manner that approaches the axis (N-N) of the joint as it tends towards the opening side. The end (A) of the center line (Xa) of the ball track of the first raceway groove part (7a) is located at a position closer to the opening side than the center of the joint (O), and the center line (Xb) of the ball track of the second raceway groove part (7b) is connected to this end (A). The center line (Y) of the ball track of the raceway groove of the inner joint member is formed to be mirror-symmetrical with the center lines (X) of the ball tracks of the paired raceway grooves of the outer joint member with respect to the plane (P) which contains the center of the joint (O) and is orthogonal to the axis (N-N) of the joint in the state where the working angle is 0°. Thus, an automatic ball assembling method for a high-working-angle and high-efficiency cross-raceway groove type constant velocity universal joint can be realized.

[0023] The above constant velocity universal joint is characterized in that the center of curvature of the axially extending arcuate raceway groove of the outer joint member is offset from the center of curvature of the axially extending arcuate raceway groove of the inner joint member by an equal distance in the opposite axial direction with respect to the center of the joint. Thus, an automatic ball assembling method for a lightweight and compact constant velocity universal joint of the ball cage type can be realized.

[0024] Advantages of the Invention

[0025] According to the present invention, an automatic ball assembling method for a constant velocity universal joint can be realized, which can achieve automatic ball assembly regardless of the raceway groove form such as a constant velocity universal joint of the crossed raceway groove type and internal specifications such as a constant velocity universal joint of the ball cage type. Description of the Drawings

[0026] Figure 1A is a partial longitudinal sectional view of a constant velocity universal joint for an automatic ball assembling method according to an embodiment of the present invention.

[0027] Figure 1B is Figure 1A a right side view of the constant velocity universal joint.

[0028] Figure 2A is Figure 1A a partial longitudinal sectional view of the outer joint member of the constant velocity universal joint.

[0029] Figure 2B is Figure 2A a right side view of the outer joint member.

[0030] Figure 3A is Figure 1A a left side view of the inner joint member of the constant velocity universal joint.

[0031] Figure 3B represents Figure 1A a view of the outer peripheral surface of the inner joint member of the constant velocity universal joint.

[0032] Figure 3C is Figure 1A a right side view of the inner joint member of the constant velocity universal joint.

[0033] Figure 4 represents Figure 1A a partial longitudinal sectional view showing details of the raceway groove of the outer joint member.

[0034] Figure 5 represents Figure 1A a longitudinal sectional view showing details of the raceway groove of the inner joint member.

[0035] Figure 6It is a side view of the whole device which is an example of a device for the automatic ball assembling method of a constant velocity universal joint implementing an embodiment of the present invention.

[0036] Figure 7 It is Figure 6 An enlarged top view of the device shown.

[0037] Figure 8 It represents Figure 6 The cage pressing mechanism and the cage erecting mechanism of the device shown, and it is a front view obtained by observing in the direction of the A - A line of Figure 7 The cage pressing mechanism and the cage erecting mechanism of the device shown, and it is a front view obtained by observing in the direction of the A - A line of

[0038] Figure 9 It is an enlarged view of the main part of the tilting rod mechanism, and it is Figure 10 A right side view of

[0039] Figure 10 It is an enlarged view of the main part of the tilting rod mechanism, and it is a cross - sectional view obtained by observing in the direction of the B - B line of Figure 6 The cage pressing mechanism and the cage erecting mechanism of the device shown, and it is a cross - sectional view obtained by observing in the direction of the B - B line of

[0040] Figure 11 It is Figure 6 A longitudinal cross - sectional view obtained by enlarging the main part of the chuck device of

[0041] Figure 12 It is Figure 11 A transverse cross - sectional view obtained by observing in the direction of the D - D line of

[0042] Figure 13 It is an enlarged view of the main part of the device showing the state where the tilting rod is inserted into the spline hole of the inner coupling member.

[0043] Figure 14 It is an enlarged view of the main part of the device showing the state where the tilting action of the tilting rod is completed and the balls are assembled.

[0044] Figure 15A It is a flowchart showing the old method of ball assembly.

[0045] Figure 15B It is a flowchart showing the automatic ball assembling method of this embodiment.

[0046] Figure 16 It is an enlarged top view of the inner assembly showing the ball assembly sequence.

[0047] Figure 17A It is a top view of the front fixture of the cage pressing mechanism.

[0048] Figure 17B It is a perspective view of the front fixture of the cage pressing mechanism.

[0049] Figure 18 It is an enlarged view of the main part showing a modified example of the cage pressing mechanism.

[0050] Figure 19A It is a perspective view observed from the planar direction showing the insights during the development of automatic ball assembly.

[0051] Figure 19B It is a perspective view observed from the front direction showing the insights during the development of automatic ball assembly.

[0052] Figure 19C It is a perspective view observed from the planar direction showing the insights during the development of automatic ball assembly.

[0053] Figure 19D It is a perspective view observed from the front direction showing the insights during the development of automatic ball assembly.

[0054] Figure 20A It is a partial longitudinal sectional view of a constant velocity universal joint of a different form targeted at the automatic ball assembly method of the constant velocity universal joint of the present embodiment.

[0055] Figure 20B It is Figure 20A A transverse sectional view taken along the C - C line of Detailed implementation mode

[0056] Based on Figures 1A - 5 A constant velocity universal joint targeted at the automatic ball assembly method of the constant velocity universal joint of one embodiment of the present invention will be described.

[0057] <Structure of constant velocity universal joint>

[0058] Figures 1A - 5 It represents a constant velocity universal joint targeted at the automatic ball assembly method of the constant velocity universal joint of one embodiment of the present invention, Figure 1A It is a partial longitudinal sectional view of the constant velocity universal joint, Figure 1B It is Figure 1A The right side view of the constant velocity universal joint of Figure 2A It is Figure 1A A partial longitudinal sectional view of the outer coupling member of the constant velocity universal joint of Figure 2B It is Figure 2A The right side view of the outer coupling member of Figure 3A It is Figure 1A The left side view of the inner coupling member of the constant velocity universal joint of Figure 3B It represents Figure 1A A view of the outer peripheral surface of the inner coupling member of the constant velocity universal joint of Figure 3C It is Figure 1ARight side view of the inner coupling member of the constant velocity universal joint. Figure 4 represents Figure 1A detailed partial longitudinal sectional view of the raceway groove of the outer coupling member of Figure 5 represents Figure 1A longitudinal sectional view showing details of the raceway groove of the inner coupling member of

[0059] The constant velocity universal joint 1 is a fixed constant velocity universal joint, mainly composed of an outer coupling member 2, an inner coupling member 3, balls 4, and a cage 5. As Figure 1B , Figure 2A , Figure 2B , Figure 3A , Figure 3B and Figure 3C shown, eight raceway grooves 7, 9 of each of the outer coupling member 2 and the inner coupling member 3 are inclined circumferentially with respect to the axis N - N of the coupling, and the inclination directions are formed in opposite directions in the circumferentially adjacent raceway grooves 7A, 7B and 9A, 9B. And, eight balls 4 are arranged at each intersection of the paired raceway grooves 7A, 9A and 7B, 9B of the outer coupling member 2 and the inner coupling member 3. Details of the raceway grooves 7, 9 will be described later.

[0060] The longitudinal section of the coupling is as Figure 1A shown. In order to accurately represent the forms and shapes such as the inclination state and bending state of the raceway groove extending in the axial direction, in this specification, terms such as the ball track center line are used for description. Here, the ball track center line refers to the trajectory described by the center of the ball when the ball arranged in the raceway groove moves along the raceway groove. Therefore, the inclination state of the raceway groove is the same as the inclination state of the ball track center line, and in addition, the arc-shaped or linear state of the raceway groove is the same as the arc-shaped or linear state of the ball track center line.

[0061] As Figure 1AAs shown, the raceway groove 7 of the outer coupling member 2 has a ball track center line X. The raceway groove 7 is composed of a first raceway groove portion 7a having an arc-shaped ball track center line Xa with the coupling center O as the center of curvature and a second raceway groove portion 7b having a linear ball track center line Xb. The ball track center line Xb of the second raceway groove portion 7b is smoothly connected to the ball track center line Xa of the first raceway groove portion 7a as a tangent line. It should be noted that the raceway groove 7 of the outer coupling member 2 may also be provided only with an arc-shaped portion composed of the ball track center line Xa with the coupling center O as the center of curvature. On the other hand, the raceway groove 9 of the inner coupling member 3 has a ball track center line Y. The raceway groove 9 is composed of a first raceway groove portion 9a having an arc-shaped ball track center line Ya with the coupling center O as the center of curvature and a second raceway groove portion 9b having a linear ball track center line Yb. The ball track center line Yb of the second raceway groove portion 9b is smoothly connected to the ball track center line Ya of the first raceway groove portion 9a as a tangent line. It should be noted that the raceway groove 9 of the inner coupling member 3 may also be provided only with an arc-shaped portion composed of the ball track center line Ya with the coupling center O as the center of curvature.

[0062] By arranging the centers of curvature of the ball track center lines Xa and Ya of the first raceway groove portions 7A and 9A at the coupling center O on the axis N - N of the coupling, the depth of the raceway groove can be made uniform, and the machining can be made easy. The cross-sectional shape of the raceway grooves 7 and 9 is formed into an elliptical shape or a pointed arch shape, and the raceway grooves 7 and 9 and the balls 4 are in contact at a contact angle (about 30° to 45°), so-called angular contact. Therefore, the balls 4 contact on the side surface of the raceway grooves 7 and 9 slightly away from the bottom of the raceway grooves 7 and 9.

[0063] Based on Figure 2A 、 Figure 2B The state in which the raceway groove 7 of the outer coupling member 2 is inclined in the circumferential direction with respect to the axis N - N of the coupling will be described in detail. The raceway groove 7 of the outer coupling member 2 is labeled with reference numerals 7A and 7B of the raceway grooves due to the difference in its inclination direction. As Figure 2A shown, the plane M including the ball track center line X of the raceway groove 7A and the coupling center O is inclined at an angle γ with respect to the axis N - N of the coupling. And the raceway groove 7B adjacent to the raceway groove 7A in the circumferential direction is not shown, but the plane M including the ball track center line X of the raceway groove 7B and the coupling center O is inclined at an angle γ with respect to the axis N - N in the direction opposite to the inclination direction of the raceway groove 7A. The raceway grooves 7A and 7B (and 9A and 9B described later) are inclined at an angle γ, but extend substantially along the axial direction. The raceway groove extending along the axial direction in this specification and the technical solution includes the concept inclined at an angle γ as described above.

[0064] Here, the reference numerals of the raceway grooves are supplemented. When referring to the entire raceway groove of the outer coupling member 2, the reference numeral 7 is marked. For the first raceway groove portion, the reference numeral 7a is marked, and for the second raceway groove portion, the reference numeral 7b is marked. Further, when differentiating the raceway grooves with different inclination directions, the reference numerals 7A and 7B are marked. For each first raceway groove portion, the reference numerals 7Aa and 7Ba are marked, and for the second raceway groove portion, the reference numerals 7Ab and 7Bb are marked. For the raceway grooves of the inner coupling member 3 described later, the reference numerals are marked in the same manner.

[0065] Next, based on Figure 3A 、 Figure 3B 、 Figure 3C the state in which the raceway groove 9 of the inner coupling member 3 is inclined in the circumferential direction with respect to the axis N - N of the coupling will be described in detail. The raceway grooves 9 of the inner coupling member 3 are marked with the reference numerals 9A and 9B due to their different inclination directions. As shown in Figure 3B , the plane Q including the ball track center line Y of the raceway groove 9A and the coupling center O is inclined at an angle γ with respect to the axis N - N of the coupling. And although the illustration of the raceway groove 9B adjacent to the raceway groove 9A in the circumferential direction is omitted, the plane Q including the ball track center line Y of the raceway groove 9B and the coupling center O is inclined at an angle γ with respect to the axis N - N in the direction opposite to the inclination direction of the raceway groove 9A. Considering the operability of the constant velocity universal joint 1 and the closest spherical width F of the raceway groove of the inner coupling member 3, the inclination angle γ is preferably 4° to 12°. The ball track center line Y of the raceway groove 9 of the inner coupling member 3 is formed to be mirror-symmetrical with respect to the ball track center line X of the pair of raceway grooves 7 of the outer coupling member 2, with the plane P including the coupling center O and orthogonal to the axis N - N of the coupling as a reference in the state of the working angle of 0°.

[0066] Based on Figure 4 the details of the raceway groove observed from the longitudinal section of the outer coupling member 2 will be described. Figure 4 The partial longitudinal section of Figure 2A is a cross-sectional view observed in the plane M including the ball track center line X of the raceway groove 7A of the above-mentioned Figure 4 . Therefore, strictly speaking, it is not a longitudinal cross-sectional view in the plane including the axis N - N of the coupling, but a section inclined at an angle γ. The raceway groove 7A of the outer coupling member 2 is shown in

[0067] , but since the raceway groove 7B only has the inclination direction opposite to that of the raceway groove 7A and the other structures are the same as those of the raceway groove 7A, the description thereof is omitted.On the spherical inner peripheral surface 6 of the outer coupling member 2, a raceway groove 7A is formed along the axial direction. The raceway groove 7A has a ball track center line X, and the raceway groove 7A is composed of a first raceway groove portion 7Aa having an arc-shaped ball track center line Xa with the coupling center O as the center of curvature (without axial offset) and a second raceway groove portion 7Ab having a linear ball track center line Xb. And, at the end A on the opening side of the ball track center line Xa of the first raceway groove portion 7Aa, the linear ball track center line Xb of the second raceway groove portion 7Ab is smoothly connected as a tangent line. That is, the end A is the connection point between the first raceway groove portion 7Aa and the second raceway 7Ab. Since the end A is located at a position closer to the opening side than the coupling center O, the linear ball track center line Xb of the second raceway groove portion 7Ab connected as a tangent line at the end A on the opening side of the ball track center line Xa of the first raceway groove portion 7Aa is formed to approach the axis N-N of the coupling as it tends to the opening side (refer to Figure 1A ). Thereby, the effective raceway length at the maximum working angle can be ensured, and the wedge angle can be suppressed from becoming too large.

[0068] As Figure 4 shown, let the straight line connecting the end A and the coupling center O be L. The axis N'-N' of the coupling projected on the plane M (refer to Figure 2A ) including the ball track center line X of the raceway groove 7A and the coupling center O is inclined by γ with respect to the axis N-N of the coupling, and the angle formed by the perpendicular line K at the coupling center O of the axis N'-N' and the straight line L is set as β'. The above-mentioned perpendicular line K is located on the plane P including the coupling center O in the state of the working angle 0° and orthogonal to the axis N-N of the coupling. Therefore, the angle β formed by the straight line L with respect to the plane P including the coupling center O in the state of the working angle 0° and orthogonal to the axis N-N of the coupling has a relationship of sinβ = sinβ'×cosγ.

[0069] Similarly, based on Figure 5 the longitudinal section of the inner coupling member 3 is used to explain the details of the raceway groove. Figure 5 The longitudinal section is a cross-sectional view observed in the plane Q including the ball track center line Y of the raceway groove 9A of the aforementioned Figure 3B and the coupling center O. Therefore, similar to Figure 4 , strictly speaking, it is not a longitudinal cross-sectional view of the plane including the axis N-N of the coupling, but a cross-section inclined by an angle γ. The raceway groove 9A of the inner coupling member 3 is shown in Figure 5 , but the raceway groove 9B is only inclined in the direction opposite to that of the raceway groove 9A, and other structures are the same as those of the raceway groove 9A, so the description is omitted.

[0070] On the spherical outer peripheral surface 8 of the inner coupling member 3, a raceway groove 9A is formed along the axial direction. The raceway groove 9A has a ball track center line Y, and the raceway groove 9A is composed of a first raceway groove portion 9Aa having an arc-shaped ball track center line Ya with the coupling center O as the center of curvature (without axial offset) and a second raceway groove portion 9Ab having a linear ball track center line Yb. And, at the inner end B of the ball track center line Ya of the first raceway groove portion 9Aa, the ball track center line Yb of the second raceway groove portion 9Ab is smoothly connected as a tangent line. That is, the end B is the connection point of the first raceway groove portion 9Aa and the second raceway 9Ab. Since the end B is located on the inner side of the coupling center O, the linear ball track center line Yb of the second raceway groove portion 9Ab connected as a tangent line on the inner side of the ball track center line Ya of the first raceway groove portion 9Aa is formed to tend to the inner side and approach the axis N-N of the coupling (refer to Figure 3A ). Thereby, the effective raceway length at the maximum working angle can be ensured, and the wedge angle can be suppressed from becoming too large.

[0071] As Figure 5 shown, let the straight line connecting the end B and the coupling center O be R. The axis N'-N' of the coupling projected on the plane Q including the ball track center line Y of the raceway groove 9A and the coupling center O (refer to Figure 3B ), is inclined by γ with respect to the axis N-N of the coupling. Let the angle formed by the perpendicular line K at the coupling center O of the axis N'-N' and the straight line R be β'. The above-mentioned perpendicular line K is located on the plane P that includes the coupling center O in the state of the working angle of 0° and is orthogonal to the axis N-N of the coupling. Therefore, the angle β formed by the straight line R with respect to the plane P that includes the coupling center O in the state of the working angle of 0° and is orthogonal to the axis N-N of the coupling satisfies the relationship of sinβ = sinβ'×cosγ.

[0072] Next, the angles β formed by the straight lines L and R with respect to the plane P that includes the coupling center O in the state of the working angle of 0° and is orthogonal to the axis N-N of the coupling will be described. When obtaining the working angle θ, the ball 4 moves by θ / 2 with respect to the plane P that includes the coupling center O of the outer coupling member 2 and the inner coupling member 3 and is orthogonal to the axis N-N of the coupling. The angle β is determined based on 1 / 2 of the working angle with a high usage frequency, and the range of the raceway groove contacted by the ball 4 is determined within the range of the working angle with a high usage frequency. Here, the working angle with a high usage frequency will be defined. First, the common angle of the coupling refers to the working angle generated in the fixed constant velocity universal joint of the front drive shaft when the steering wheel is in the straight-ahead state in a motor vehicle when one person is riding on a horizontal and flat road surface. The common angle is usually selected and determined between 2° and 15° according to the design conditions of each vehicle model.

[0073] Moreover, the working angle with high usage frequency refers to the working angle generated by the fixed constant velocity universal joint when the above-mentioned motor vehicle is on a curved road during continuous driving, etc., rather than the high working angle generated during right or left turns at intersections, etc. This is also determined according to the design conditions of each vehicle model. The maximum working angle with high usage frequency aims at 20°. Thus, the angle β formed by the straight lines L and R with respect to the plane P that contains the coupling center O in the state with a working angle of 0° and is orthogonal to the axis N-N of the coupling is set to 3° to 10°. However, the angle β is not limited to 3° to 10° and can be appropriately set according to the design conditions of the vehicle model. By setting the angle β to 3° to 10°, it can be applicable to various vehicle models.

[0074] According to the above-mentioned angle β, in Figure 4 , the end A of the ball track center line Xa of the first raceway groove portion 7Aa becomes the center position of the ball when it moves axially to the most open side at the working angle with high usage frequency. Similarly, in the inner coupling member 3, in Figure 5 , the end B of the ball track center line Ya of the first raceway groove portion 9Aa becomes the center position of the ball when it moves axially to the innermost side at the working angle with high usage frequency. Due to such setting, within the range of the working angle with high usage frequency, the balls 4 are located in the 7Ba and 9Ba (refer to Figure 2A , Figure 3B ) where the inclination direction is opposite to that of the first raceway groove portions 7Aa and 9Aa of the outer coupling member 2 and the inner coupling member 3. Therefore, forces in opposite directions act on the pocket portions 5a adjacent to the balls 4 in the circumferential direction of the cage 5, and the cage 5 is stable at the position of the coupling center O (refer to Figure 1A ). Therefore, the contact force between the spherical outer peripheral surface 12 of the cage 5 and the spherical inner peripheral surface 6 of the outer coupling member 2, and the contact force between the spherical inner peripheral surface 13 of the cage 5 and the spherical outer peripheral surface 8 of the inner coupling member 3 are suppressed. The coupling operates smoothly under high loads and high-speed rotations, torque loss and heat generation are suppressed, and the aging resistance is improved.

[0075] The overall description of the constant velocity universal joint 1 is as described above. Next, with reference to an example of implementing the ball automatic assembly method, the ball automatic assembly method of the constant velocity universal joint of the present embodiment will be described. The device for implementing this ball automatic assembly method is an example and is not limited thereto. Within the scope of not departing from the gist of the ball automatic assembly method of the constant velocity universal joint of the present invention, it can be implemented in various ways.

[0076] <Overall and Main Structure of the Device for Implementing the Ball Automatic Assembly Method>

[0077] Regarding an example of the device for implementing the ball automatic assembly method, Figures 6 - 12 shows the overall device and the main structure.Figure 6 FIG. 1 is a side view of an entire apparatus which is an example of an apparatus for a ball automatic assembling method of a constant velocity universal joint showing one embodiment of the present invention. Figure 7 FIG. 2 is an enlarged plan view of the apparatus. Figure 8 FIG. 3 shows a cage pressing mechanism and a cage erecting mechanism of the apparatus, and is a front view obtained by observing in the direction of arrow A - A in Figure 7 FIG. 4. Figure 9 FIG. 5 is an enlarged view of a main part of an inclined rod mechanism, and is a right side view of Figure 10 FIG. 6. Figure 10 FIG. 7 is an enlarged view of a main part of the inclined rod mechanism, and is a sectional view obtained by observing in the direction of arrow B - B in Figure 6 FIG. 8. Figure 11 FIG. 9 is a longitudinal sectional view showing an enlarged main part of a chuck device of Figure 6 FIG. 10, Figure 12 and FIG. 10 is a transverse sectional view obtained by observing in the direction of arrow D - D in Figure 11 FIG. 11.

[0078] As shown in Figure 6 FIG. 12, an apparatus 50 for implementing the ball automatic assembling method mainly includes: a base part 51, a main frame part 52, an inclination operation part 53 of an inner assembly I composed of an inner coupling member and a cage, a lifting operation part 54 for lifting and lowering the inclination operation part 53 of the inner assembly I, a chuck device 55 for an outer coupling member 2, and a ball supply part 90 (refer to Figure 7 , Figure 14 ). The inclination operation part 53 of the inner assembly I is slidably provided through a linear guide device 57 and a guide rail 59. The lifting operation part 54 performs a lifting operation through a linear motion device 58 (for example, an air cylinder).

[0079] The chuck device 55 for the outer coupling member 2 is provided on the base part 51. The chuck device 55 is rotated in the rotational direction by a predetermined phase angle corresponding to a raceway groove for assembling balls 4. An axis of the chuck device 55 coincides with an axis of an inclined rod mechanism 60 of the inclination operation part 53 of the inner assembly I. Thus, in a state where the inclined rod 61 of the inclined rod mechanism 60 is not inclined, a front end shaft part 61b of the inclined rod 61 can be inserted into a spline hole of an inner coupling member 3 of the inner assembly I assembled inside the outer coupling member 2.

[0080] The inclination operation part 53 of the inner assembly I includes an inclined rod mechanism 60, a cage pressing mechanism 65, and a cage erecting mechanism 70. As shown in Figure 6 , Figure 7As shown, the frame 62 of the tilting portion 53 of the inner assembly I is configured in a substantially U-shape when viewed from the planar direction. A linear guide device 57 is mounted on the side plate portion 62a via a base plate 62c and is slidable along a guide rail 59. Linear motion devices 63, 64 (e.g., air cylinders) are mounted on the side plate portion 62a of the frame 62 to operate a cage pressing mechanism 65 and a cage erecting mechanism 70. Here, the cage pressing mechanism in the technical solution being driven by a drive source different from that of the tilting rod means the above-mentioned meaning is included.

[0081] A connecting plate 73 is provided across a pair of upright plate portions 62b of the frame 62, and a pivot shaft 66 is provided on the connecting plate 73. The pivot shaft 66 serves as the swing fulcrum of the cage pressing rod 65a of the cage pressing mechanism 65 and the cage erecting rod 70a of the cage erecting mechanism 70, respectively. The base ends of the cage pressing rod 65a and the cage erecting rod 70a are connected to the linear motion devices 63, 64 via a link mechanism 67 (see Figure 6 ). By the stretching motion of the linear motion devices 63, 64, the cage pressing rod 65a and the cage erecting rod 70a rotate rightward (rotate in the clockwise direction) respectively. The advancing ends of the cage pressing rod 65a and the cage erecting rod 70a are defined by stoppers 71, 72 respectively. Thus, the advancing ends of the cage pressing rod 65a of the cage pressing mechanism 65 and the cage erecting rod 70a of the cage erecting mechanism 70 can be reliably defined.

[0082] In the method for automatically assembling balls of the constant velocity universal joint and the device for implementing the assembling method in this embodiment, a structure in which a cage pressing mechanism 65 and a cage erecting mechanism 70 are provided simultaneously is exemplified. However, the cage pressing mechanism 65 is a necessary mechanism, but the cage erecting mechanism 70 can also be omitted according to circumstances.

[0083] On the front end side of the pair of upright plate portions 62b of the frame 62 ( Figure 7 the upper end side), a tilting rod mechanism 60 is provided. The connecting shaft portion 80 of the tilting rod mechanism 60 is shown on the upper end side of Figure 7 . The ball supply portion 90 is disposed opposite to the connecting shaft portion 80 in an inclined state (inclination angle α = 22.5°).

[0084] Herein, the reason for arranging the ball supply unit 90 in an inclined state in a facing manner will be supplemented and described below. The constant velocity universal joint 1 targeted by the ball automatic assembly method and the device for implementing the assembly method of the constant velocity universal joint according to the present embodiment has the following structure as described above. That is, the eight raceway grooves 7 and 9 of the outer coupling member 2 and the inner coupling member 3 respectively are inclined in the circumferential direction with respect to the axis N - N of the coupling, and the inclination directions are formed in opposite directions in the circumferential direction in the adjacent raceway grooves 7A, 7B and 9A, 9B. And, eight balls 4 are arranged at each intersection of the paired raceway grooves 7A, 9A and 7B, 9B of the outer coupling member 2 and the inner coupling member 3. Considering the ball assembly operation at each intersection of the phase angles of the eight balls 4, it is arranged in a facing manner in an inclined state with α = 22.5°. In contrast, in the case of the ball cage type constant velocity universal joint described later, the raceway grooves of the inner coupling member and the outer coupling member are not inclined in the circumferential direction, and the plane including the ball track center line of the raceway groove and the coupling center is in the same direction as the axis of the coupling, so it is arranged in a non-inclined facing manner (α = 0°).

[0085] As viewed in the direction of the A - A line in Figure 7 obtained by looking, Figure 8 as shown, two linear motion devices 63 and 64 are provided on the side plate portion 62a of the frame 62 of the tilt operation portion 53 of the inner assembly I. One linear motion device 63 is connected to the cage pressing rod 65a via a link mechanism 67, and the other linear motion device 64 is connected to the cage erecting rod 70a via a link mechanism 67. In addition, the cage pressing rod 65a and the cage erecting rod 70a are accommodated in the opening portion 61a of the tilt rod 61 to avoid interference.

[0086] In Figure 6 the sectional view obtained by looking in the direction of the B - B line in Figure 10 enlargely shows the main part of the tilt rod mechanism 60. The swing shafts 82 and 83 are rotatably supported via rolling bearings 81 at the lower parts of the pair of vertical plate portions 62b of the frame 62. As Figure 7 shown, a connecting shaft portion 80 is provided between the pair of swing shafts 82 and 83, but is omitted in Figure 10 the illustration. A gantry - type swing frame 84 is provided on the swing shafts 82 and 83, and a tilt rod 61 is provided on the upper plate portion 84a of the swing frame 84, and the aforementioned opening portion 61a is formed in the tilt rod 61.

[0087] An upper plate portion 62c is provided across the pair of vertical plate portions 62b of the frame 62, and a rotating device 100 (such as a cylinder) is provided on the upper plate portion 62c. An arm member 102 is installed on the output shaft 101 of the rotating device 100. An arm member 103 is also installed on the swing shaft 82. As Figure 9As shown, an arm member 102 mounted on the output shaft 101 of the rotating device 100 and an arm member 103 mounted on the swing shaft 82 are connected by a connecting member 104. Thus, the swing shaft 82 swings at a specified angle (ball assembly angle θm, for example, about 72°), and the inclined rod 61 provided on the swing frame 84 swings about the central position ( Figure 10 T-T line) of the front end shaft portion 61b. The central position of the front end shaft portion 61b is the axial position that becomes the coupling center O of the inner coupling member 3 (refer to Figure 3B ). Thus, the tilting operation of the inner assembly I to the ball assembly angle θm and the return operation of the inner assembly I to the horizontal posture can be performed.

[0088] Based on Figure 11 , Figure 12 The chuck device 55 of the outer coupling member 2 will be described. Figure 11 is a longitudinal sectional view showing an enlarged main part of the chuck device 55 of Figure 6 , Figure 12 is a cross-sectional view obtained by observing in the direction of the D-D line of Figure 11 . The chuck device 55 is provided on the base portion 51. A setting table 110 is provided on the upper part of the substantially cylindrical portion 114 of the chuck device 55. A guide hole 111 for the rod shaft portion 2b of the outer coupling member 2 and a reference surface 112 for abutting against the back surface of the outer coupling member 2 are formed on the setting table 110. A chuck holding portion 113 is formed below the setting table 110, and the holding portion 113 is constituted by, for example, a three-jaw chuck. The holding portion 113 advances to the position of the double-dot chain line, and the holding portion 113 clamps and fixes the rod shaft portion 2b of the outer coupling member 2 provided on the setting table 110.

[0089] A main shaft portion 115 is provided on the substantially cylindrical portion 114 and is supported by a rolling bearing 116 so as to be rotatable. By rotating and driving the main shaft portion 115 with appropriate power (for example, synchronous belt drive), the chuck device 55 can be indexed. Thus, the rotational phase of the supply port 91 of the ball supply portion 90 (refer to Figure 7 , Figure 14 ) can be made to correspond to the raceway groove 7 of the outer coupling member 2. As Figure 6 shown, the cam base plate 118 is brought into contact with and guided by the guide portion 117 provided on the upper part of the substantially cylindrical portion 114 of the chuck device 55, thereby suppressing the swing of the chuck device 55.

[0090] The above is an example of the overall device and the main structure related to the device for the ball automatic assembly method of the constant velocity universal joint according to the present embodiment. Next, in conjunction with an example of the device for implementing the above-mentioned ball automatic assembly method, the ball assembly operation of the ball automatic assembly method of the constant velocity universal joint according to the present embodiment will be described.

[0091] <Ball assembly operation of the device for implementing the ball automatic assembly method>

[0092] As shown in Figure 6 , the tilting operation part 53 of the inner assembly I rises and retracts to the upper end. In this state, the tilting rod 61 is not tilted but in a vertical posture. The outer coupling member 2 is set on the chuck device 55, and then the holding part 113 advances, and the holding part 113 clamps and fixes the rod shaft part 2b of the outer coupling member 2. The inner assembly I is assembled horizontally on the inner peripheral part of the outer coupling member 2, and the axis of the outer coupling member 2 coincides with that of the inner assembly I. After clamping and fixing the outer coupling member 2 to the chuck device 55, starting from the state shown in Figure 6 , the tilting operation part 53 descends, and the front end shaft part 61b of the tilting rod 61 is inserted into the spline hole of the inner coupling member 3 of the inner assembly I. This state is as shown in Figure 13 . Figure 13 is an enlarged view of the main part of the device showing the state where the tilting rod 61 is inserted into the spline hole of the inner coupling member 3.

[0093] Then, the tilting rod 61 performs a tilting operation. During this tilting operation, the front end of the cage erection rod 70a presses the end of the cage 5, and the inner coupling member 3 and the cage 5 of the inner assembly I perform tilting operations. If the front end of the cage erection rod 70a presses the end of the cage 5 during the initial operation of the tilting rod 61, the tilting operations of the inner coupling member 3 and the cage 5 can be smoothly performed. The advancing end of the cage erection rod 70a generated by the stretching operation of the linear motion device 64 is defined by the stopper 72.

[0094] As shown in Figure 14 , the inner coupling member 3 is tilted relative to the outer coupling member 2 to the ball assembly angle θm, and a state is formed in which the concave pocket 5a of the cage 5 is exposed from the opening end of the outer coupling member 2, and the tilting operation of the tilting rod 61 is completed. Figure 14 is an enlarged view of the main part of the device showing the state where the tilting operation of the tilting rod 61 is completed and the balls are assembled. One ball 4 is supplied from the supply port 91 of the ball supply part 90 to the concave pocket 5a of the cage 5 exposed from the opening end of the outer coupling member 2, thereby assembling the ball 4. This ball 4 is set as the first ball 4. The ball supply part 90 is initially adjusted for product change according to the model of the constant velocity universal joint and is set at the position of Figure 14 . That is, the ball supply part 90 is also provided in Figure 6 , Figure 11 , Figure 13 , etc., but the illustration is omitted.

[0095] Then, the tilting rod 61 performs a return operation. As shown inFigure 14 As shown, while the tilting lever 61 performs a return action, the front end of the cage pressing lever 65a presses the end of the cage 5, and the inner coupling member 3 and the cage 5 of the inner assembly I perform a return action. If the cage pressing lever 65a presses the end of the cage 5 during the initial action of the tilting lever 61, the balls 4 enter the raceway groove 7 of the outer coupling member 2, thus eliminating the problem of the balls 4 getting stuck in the raceway groove 7. Therefore, the return actions of the inner coupling member 3 and the cage 5 can be performed smoothly. The advancing end of the cage pressing lever 65a based on the stretching action of the linear motion device 63 is defined by the stopper 71. When the inner assembly I returns to the horizontal state, the indexing chuck device 55 is rotated to assemble the next ball 4.

[0096] Based on Figure 16 The assembly sequence of the balls 4 into the inner assembly I will be specifically described. The first ball described above is labeled with the reference numeral 4(1). The rotational phase of this ball 4(1) is set to 0°. Based on the rotational phase of 0° of this ball 4(1), the rotational phases of the second ball 4(2) to the eighth ball 4(8) going to the right (clockwise) are: the second ball 4(2) is 225°, the third ball 4(3) is 90°, the fourth ball 4(4) is 135°, the fifth ball 4(5) is 45°, the sixth ball 4(6) is 315°, the seventh ball 4(7) is 270°, and the eighth ball 4(8) is 180°. By setting the assembly sequence and rotational phases of the balls 4 in this way, the assembly of the balls 4 becomes smooth.

[0097] After assembling the first ball 4(1), the chuck device 55 is indexed to the rotational phase of 225°, and the tilting action of the inner assembly I, the assembly of the ball 4(2), and the return action are performed. And the tilting action of the inner assembly I, the assembly of the ball 4, and the return action are repeatedly performed in sequence until the eighth ball 4(8) is assembled. Thus, the automatic ball assembly process is completed.

[0098] The above-described assembly sequence of the balls 4 is an example, and the assembly sequence and rotational phases of the balls 4 can be appropriately changed. Alternatively, the clearance between the pocket 5a of the cage 5 and the ball 4 can be set to a slightly excessive interference amount. In a state where one reference ball is assembled into the inner assembly I in advance, the inner periphery of the outer coupling member 2 is assembled, and then the remaining balls are assembled in sequence.

[0099] In Figure 15A , Figure 15B summarizes the process flow for comparing the automatic ball assembly method of this embodiment with the old method. Figure 15A Indicates the old method, Figure 15BShows the automatic ball assembly method of this embodiment. In the automatic ball assembly method of this embodiment, while the tilting rod is performing a return motion, the cage pressing rod presses the end of the cage, and the inner coupling member and the cage of the inner assembly perform a return motion. Since the balls enter the raceway groove of the outer coupling member, the problem of the balls getting stuck in the raceway groove is eliminated. Therefore, the return motion of the inner coupling member and the cage can be smoothly performed.

[0100] Figure 17A , Figure 17B Indicates the front clamp 65b of the cage pressing mechanism 65. Figure 17A Is a top view, Figure 17B Is a perspective view. The contact surface 65c of the front clamp 65b of the cage pressing mechanism 65 that contacts the cage 5 is formed into a smooth arc shape with a radius of curvature R. The radius of curvature R is appropriately set to about 20 mm to 50 mm. In addition, the contact surface 65c is surface hardened by high-frequency quenching or the like. Therefore, the generation of damage to the end face of the cage 5 can be suppressed, and the wear resistance is also good.

[0101] <Deformation example of the cage pressing mechanism>

[0102] Figure 18 Indicates a deformation example of the cage pressing mechanism 65. Figure 18 Is an enlarged view of the main part of this deformation example. A cage pressing mechanism 65 is attached to the tilting rod 61. A buffer device 68 is installed on the tilting rod 61 and the cage pressing mechanism 65 is added. In the tilting rod 61 of the above-mentioned embodiment, it is driven by a separately provided linear motion device, but in this deformation example, no separate driving device is provided. Therefore, the cage pressing mechanism can be simplified and can be constructed at low cost. The other structures and functions of the tilting rod 61 and the cage pressing mechanism 65 are the same as those of the tilting rod mechanism 65 and the cage pressing mechanism 65 of the above-mentioned embodiment. The same reference numerals are used for parts having the same functions, and only the main points are described.

[0103] The cage pressing mechanism 65 of this deformation example is provided on the tilting rod 61. The cage pressing mechanism 65 is composed of a buffer device 68 and a cage pressing rod 65a. The buffer device 68 is installed on the tilting rod 61, and the cage pressing rod 65a abuts against the end of the cage 5. The cage pressing rod 65a moves integrally with the tilting rod 61 via the buffer device 68. Here, the cage pressing mechanism attached to the tilting rod and driven by the drive source of the tilting rod in the technical solution includes the above meaning.

[0104] <Structure of constant velocity universal joints in different forms for the automatic ball assembly method>

[0105] Based on FIG. 20, constant velocity universal joints of different forms for the ball automatic assembly method of the constant velocity universal joint of the present embodiment will be described. Figure 20A is a partial longitudinal sectional view, Figure 20B and Figure 20A is a cross-sectional view taken along line C-C of the figure.

[0106] As Figure 20A , Figure 20B shown, the constant velocity universal joint 201 of the ball cage type mainly consists of an outer coupling member 202, an inner coupling member 203, balls 204, and a cage 205. Eight arc-shaped raceway grooves 207 extending axially are formed on the spherical inner peripheral surface 206 of the outer coupling member 202, having an open side and an inner side separated axially. Eight arc-shaped raceway grooves 209 extending axially are formed on the spherical outer peripheral surface 208 of the inner coupling member 203. One of the eight balls 204 for transmitting torque is assembled between the raceway groove 207 of the outer coupling member 202 and the corresponding raceway groove 209 of the inner coupling member 203. The cage 205 has a pocket 205a for accommodating the balls 204, and has a spherical outer peripheral surface 212 and a spherical inner peripheral surface 213 that are in sliding contact with the spherical inner peripheral surface 206 of the outer coupling member 202 and the spherical outer peripheral surface 208 of the inner coupling member 203, respectively.

[0107] The centers of curvature of the spherical inner peripheral surface 206 of the outer coupling member 202 and the spherical outer peripheral surface 208 of the inner coupling member 203 are both formed at the center O of the coupling. In contrast, the center of curvature Oo of the raceway groove 207 of the outer coupling member 202 and the center of curvature Oi of the raceway groove 209 of the inner coupling member 203 are offset by an equal distance f1 in the opposite axial direction with respect to the center O of the coupling. Thus, when the coupling has a working angle, the balls 204 are always guided on the plane that bisects the angle formed by the two axes of the outer coupling member 202 and the inner coupling member 203, and the rotational torque is transmitted isostatically between the two shafts.

[0108] In order to achieve lightweight and compactness, the above-mentioned constant velocity universal joint 201 of the ball cage type, for example, has an internal specification that reduces the amount of raceway offset f1. However, when the inclination of the axis of the inner coupling member is returned by using an inclined rod, the balls can be automatically assembled by simultaneously pressing in the cage using a cage pressing mechanism. The foregoing content regarding the ball automatic assembly method of the constant velocity universal joint of the foregoing embodiment, the overall device and the main structure related to an example of the device for implementing this assembly method, the ball assembly operation, the assembly sequence of the balls into the inner assembly I, etc. are also the same in the constant velocity universal joint 201 of the ball cage type, and thus applicable.

[0109] In the embodiment described above, the case where the number of balls of the constant velocity universal joint is eight is illustrated, but the number of balls may be appropriately six to ten or more.

[0110] The present invention is in no way limited by the foregoing embodiments, and of course can be further implemented in various ways without departing from the gist of the present invention. The scope of the present invention is shown by the claims, and also includes the equivalent meanings described in the claims and all changes within the scope.

[0111] Explanation of reference numerals:

[0112] 1, 201 Constant velocity universal joint

[0113] 2, 202 Outer coupling member

[0114] 3, 203 Inner coupling member

[0115] 4, 204 Ball

[0116] 5, 205 Cage

[0117] 5a, 205a Pocket

[0118] 6, 206 Spherical inner peripheral surface

[0119] 7, 207 Raceway groove

[0120] 7a First raceway groove portion

[0121] 7b Second raceway groove portion

[0122] 8, 208 Spherical outer peripheral surface

[0123] 9, 209 Raceway groove

[0124] 9a First raceway groove portion

[0125] 9b Second raceway groove portion

[0126] 12, 212 Spherical outer peripheral surface

[0127] 13, 213 Spherical inner peripheral surface

[0128] M Plane including the ball track center line

[0129] N Axis of the coupling

[0130] O Center of the coupling

[0131] Oo Center of curvature

[0132] Oi Center of curvature

[0133] P Plane

[0134] X ball rail center line

[0135] Xa ball rail center line

[0136] Xb ball rail center line

[0137] Y ball rail center line

[0138] Ya ball rail center line

[0139] Yb ball rail center line.

Claims

1. A method for automatically assembling balls of a constant velocity universal joint, the constant velocity universal joint comprising: an outer joint member having a plurality of raceways extending axially on a spherical inner peripheral surface, and having an open side and an inner side separated axially; an inner joint member having a plurality of raceways extending axially on a spherical outer peripheral surface; a plurality of balls disposed between the raceways of the outer joint member and the corresponding raceways of the inner joint member to transmit torque; and a cage having pockets for receiving the balls and having a spherical outer peripheral surface and a spherical inner peripheral surface that are in sliding contact with the spherical inner peripheral surface of the outer joint member and the spherical outer peripheral surface of the inner joint member, respectively, characterized in that, an inner assembly obtained by fitting the spherical outer peripheral surface of the inner joint member into the spherical inner peripheral surface of the cage is fitted into the spherical inner peripheral surface of the outer joint member, and the cage, the inner joint member, and the outer joint member are arranged in a state where their respective axes are substantially aligned, the axis of the inner joint member is inclined relative to the axis of the outer joint member by using an inclined rod, and the balls are assembled into the pockets of the cage exposed at the open end of the outer joint member, then, in order to assemble the balls into other pockets of the cage, when the inclination of the axis of the inner joint member is returned by using the inclined rod, the cage is pressed in by using a cage pressing mechanism.

2. The method for automatically assembling balls of a constant velocity universal joint according to claim 1, characterized in that, when the axis of the inner joint member is inclined relative to the axis of the outer joint member by using the inclined rod, the cage is pressed in by using a cage erecting rod.

3. The method for automatically assembling balls of a constant velocity universal joint according to claim 1 or 2, characterized in that, the cage pressing mechanism is driven by a drive source different from the drive source of the inclined rod.

4. The method for automatically assembling balls of a constant velocity universal joint according to claim 1 or 2, characterized in that, the cage pressing mechanism is attached to the inclined rod and is driven by the drive source of the inclined rod.

5. The method for automatically assembling balls of a constant velocity universal joint according to any one of claims 1 to 4, characterized in that, the constant velocity universal joint is of a crossed raceway type. In the raceways of the outer joint member, the center line of the ball track has an arc-shaped portion with the center of the joint (O) as the center of curvature. The plane (M) including the center line of the ball track and the center of the joint (O) is inclined with respect to the axis (N - N) of the joint, and the inclination directions of the plane (M) in the circumferentially adjacent raceways are opposite to each other. The center line of the ball track of the raceways of the inner joint member is formed to be mirror-symmetrical with the center lines of the ball tracks of the paired raceways of the outer joint member with respect to a plane (P) that includes the center of the joint (O) and is orthogonal to the axis (N - N) of the joint in a state of a working angle of 0°.

6. The method for automatically assembling balls of a constant velocity universal joint according to any one of claims 1 to 5, characterized in that the raceway groove of the outer coupling member of the constant velocity universal joint is composed of a first raceway groove portion (7a) located on the inner side and a second raceway groove portion (7b) located on the opening side. The first raceway groove portion (7a) has an arc-shaped ball track center line (Xa) with the coupling center (O) as the center of curvature. The plane (M) containing at least the ball track center line (Xa) and the coupling center (O) is inclined with respect to the axis (N-N) of the coupling, and the inclination directions of the circumferentially adjacent first raceway groove portions (7a) are opposite to each other. When the ball track center line (Xb) of the second raceway groove portion (7b) is projected onto the plane (M), the ball track center line (Xb) has a straight-line portion, and this straight-line portion is formed to be inclined in a manner that approaches the axis (N-N) of the coupling as it tends towards the opening side. The end (A) of the ball track center line (Xa) of the first raceway groove portion (7a) is located on the opening side relative to the coupling center (O), and the ball track center line (Xb) of the second raceway groove portion (7b) is connected to this end (A). The ball track center line (Y) of the raceway groove of the inner coupling member is formed to be mirror-symmetrical with the ball track center lines (X) of the paired raceway grooves of the outer coupling member with respect to the plane (P) that contains the coupling center (O) and is orthogonal to the axis (N-N) of the coupling in the state of the working angle being 0°.

7. The method for automatically assembling balls of a constant velocity universal joint according to any one of claims 1 to 4, characterized in that in the constant velocity universal joint, the center of curvature of the axially extending arc-shaped raceway groove of the outer coupling member and the center of curvature of the axially extending arc-shaped raceway groove of the inner coupling member are equidistantly offset from the center of the coupling towards the opposite axial sides.

Images