Fixed type constant velocity universal joint

Abstract

The diameter (E) of the cylindrical surface (5d) of the cage (5) is smaller than the apparent maximum outer diameter (D1) of the inner coupling member (3) when viewed from the axial direction of the cage (5), with the axis of the inner coupling member (3) orthogonal to the axis of the cage (5) and the two raceway grooves (90, 91) of the inner coupling member (3) being 180 degrees out of phase. Furthermore, the diameter (E) of the cylindrical surface (5d) of the cage (5) is larger than the apparent maximum outer diameter (D3) of the inner coupling member (3) when viewed from the axial direction of the cage (5), with the axis of the inner coupling member (3) tilted at an angle (α) relative to the surface orthogonal to the axis of the cage (5) and the two raceway grooves (90, 91) of the inner coupling member (3) being 180 degrees out of phase with the inner circumferential surface of the cage (5).

Description

Technical Field

[0001] This invention relates to a fixed constant velocity universal joint, specifically a fixed constant velocity universal joint used in the power transmission systems of motor vehicles and various industrial machinery, which allows only angular displacement between the two shafts on the driving and driven sides. Background Technology

[0002] For example, in the drive shaft of a motor vehicle, a sliding constant velocity universal joint with a small maximum working angle but capable of axial displacement while having a working angle is usually installed on the inner side (differential gear side), while a fixed constant velocity universal joint with a large working angle but no axial displacement is installed on the outer side (wheel side) because the wheel is turned.

[0003] As fixed constant velocity universal joints, ball cage type constant velocity universal joints (also known as BJ type) and root-cut-free type constant velocity universal joints (also known as UJ type) are known. Among them, as a means to ensure strength, load capacity, durability and further compactness while reducing temperature rise and torque loss during operation, there is an eight-ball type fixed constant velocity universal joint (Patent Document 1) as shown in Figure 17. This fixed constant velocity universal joint 101 is a ball cage type constant velocity universal joint, mainly composed of an outer coupling member 102, an inner coupling member 103, torque-transmitting balls 104 and a cage 105. Eight torque-transmitting balls 104 are inserted into the axially extending arc-shaped raceway grooves 107 and 109 of the outer coupling member 102 and the inner coupling member 103, and each ball 104 is held in the ball pocket 105a of the cage 105. The cage 105 is positioned on the axial side relative to the ball bag 105a (in Figure 17A The inner circumferential surface of the annular portion 105b (right side) is provided with a cylindrical surface 105c for inserting the inner coupling component 103. The curvature centers of the raceway grooves 107 and 109 are offset by an equal distance f from the coupling center to the opposite axial direction.

[0004] Recently, with the aim of improving the environmental performance of motor vehicles, there is a demand for further high efficiency. In order to achieve higher performance than the aforementioned fixed constant velocity universal joint with eight ball bearings, a fixed constant velocity universal joint with a raceway cross type, as shown in Figure 19 (Patent Document 2), has been proposed to reduce heat generation by reducing the contact between the spherical outer and inner circumferential surfaces of the cage. This fixed constant velocity universal joint 151 mainly consists of an outer coupling member 152, an inner coupling member 153, torque-transmitting balls 154, and a cage 155. Eight torque-transmitting balls 154 are inserted into the axially extending arc-shaped raceway grooves 157 and 159 of the outer coupling member 152 and the inner coupling member 153, and each ball 154 is held in the ball pocket 155a of the cage 155. The balls 154 are positioned on the axial side of the cage 155, closer to the ball pocket 155a. Figure 19A The inner circumferential surface of the annular portion 155b (right side) is provided with a cylindrical surface 155c for inserting the inner coupling component 153. Adjacent raceway grooves 157 and 159 in the circumferential direction are inclined to opposite sides relative to the axis. Opposite raceway grooves 157 and 159 in the radial direction are inclined to opposite sides relative to the axis. The center of curvature of the raceway grooves 157 and 159 coincides with the center of the coupling.

[0005] Furthermore, various studies have been conducted on improving the efficiency (Patent Document 3) and increasing the angle (Patent Document 4) of the fixed constant velocity universal coupling with cross-type raceway grooves.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent No. 3859267

[0009] Patent Document 2: Japanese Patent No. 5138449

[0010] Patent Document 3: Japanese Patent No. 6113459

[0011] Patent Document 4: Japanese Patent No. 5912419 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] In the eight ball-cage type fixed constant velocity universal couplings shown in Patent Document 1, such as Figure 18As shown, with the inner coupling member 103's axis orthogonal to the cage 105's axis and the two raceway grooves 109 (the upper and lower raceway grooves 109 in the figure) with a phase difference of 180 degrees between them and the inner circumference of the cage, the apparent outer diameter D' of the inner coupling member 103 when viewed from the axial direction of the cage 105 (direction T in the figure) is slightly smaller than the diameter E' of the cylindrical surface 105c of the cage 105 (E'>D'). Therefore, the inner coupling member 103 can be inserted into the inner circumference of the cage 105 via the cylindrical surface 105c (refer to arrow U).

[0014] On the other hand, in fixed constant velocity universal couplings with raceway tolerance type, such as Figure 10 As shown, the adjacent raceway grooves 159 of the inner coupling member 153 are inclined to opposite sides relative to the axis, so the circumferential width of the spherical portion 153a provided between the raceway grooves 159 narrows as it tends toward one side of the axial direction or the other side of the axial direction. Therefore, when the phase of the inner coupling member 153 is adjusted such that the axis of the inner coupling member 153 is orthogonal to the axis of the cage 155 and the two raceway grooves 159 of the inner coupling member 153 are 180 degrees out of phase with the inner circumferential surface of the cage, the axial direction of the cage 155 ( Figure 10 When observing the inner coupling member 153 from the orthogonal direction of the paper, the apparent outer diameter of the inner coupling member 153 becomes uneven. Specifically, the apparent outer diameter D1 of the inner coupling member 153 at the wider circumferential portion of the spherical part 153a is slightly larger than the apparent outer diameter D2 at the narrower circumferential portion of the spherical part 153a (D1 > D2). As shown in the figure, if the maximum apparent outer diameter of the inner coupling member 153 (≈D1) is greater than the diameter E of the cylindrical surface 155c of the cage 155, the inner coupling member 153 cannot be installed into the inner circumference of the cage 155. Therefore, the cylindrical surface 155c of the cage 155 needs to be enlarged, and the wall thickness in the radial direction of the annular portion 155b of the cage 155 becomes thinner, thus resulting in a decrease in the strength of the cage 155.

[0015] Therefore, the object of the present invention is to avoid a decrease in the strength of the cage in a fixed constant velocity universal coupling with a cross-type raceway groove.

[0016] Methods for solving problems

[0017] The present invention, which was made to solve the above-mentioned problems, is characterized by having: an outer coupling member having eight raceway grooves formed on its spherical inner circumferential surface;

[0018] The inner coupling component has eight raceway grooves formed on its spherical outer circumferential surface;

[0019] Eight balls, sandwiched between the raceway grooves of the outer coupling member and the raceway groove of the inner coupling member, transmit torque; and

[0020] The cage has a spherical outer peripheral surface that engages with the spherical inner peripheral surface of the outer coupling member, a spherical inner peripheral surface that engages with the spherical outer peripheral surface of the inner coupling member, eight ball pockets each holding one of the ball balls, and a cylindrical surface disposed at the axial end of the inner peripheral surface, wherein...

[0021] The outer coupling component has a first raceway groove with an arc-shaped ball track centerline Xa, and the inner coupling component has a first raceway groove with an arc-shaped ball track centerline Ya.

[0022] The plane containing the ball track centerline Xa of the first raceway groove portion of each raceway groove of the outer coupling component and the plane containing the ball track centerline Xa of the first raceway groove portion of the raceway groove adjacent to each raceway groove are inclined at an angle γ to the opposite side relative to the axial direction.

[0023] The plane containing the ball track centerline Ya of the first raceway groove portion of each raceway groove of the inner coupling component and the plane containing the ball track centerline Ya of the first raceway groove portion of the raceway groove adjacent to each raceway groove are inclined at an angle γ to the opposite side relative to the axial direction.

[0024] The plane containing the first raceway groove portion of the outer coupling member, the ball track centerline Xa, and the plane containing the first raceway groove portion of the inner coupling member, which is radially opposite to the outer coupling member, are inclined to opposite sides relative to the axial direction.

[0025] The diameter E of the cylindrical surface of the cage is smaller than the apparent maximum outer diameter D1 of the inner coupling member when viewed from the axial direction of the cage, with the axis of the inner coupling member orthogonal to the axis of the cage and the two raceway grooves of the inner coupling member 180 degrees out of phase facing the inner circumferential surface of the cage.

[0026] The diameter (E) of the cylindrical surface of the cage is larger than the apparent maximum outer diameter D3 of the inner coupling member when viewed from the axial direction of the cage, with the axis of the inner coupling member tilted at an angle α relative to a plane orthogonal to the axis of the cage and the two raceway grooves of the inner coupling member being 180 degrees out of phase facing the inner circumferential surface of the cage.

[0027] The inventors have focused on the fact that the apparent maximum outer diameter of the inner coupling member of a fixed constant velocity universal coupling of raceway cross type is greater when the axis of the inner coupling member is inclined relative to a plane orthogonal to the axis of the cage (see Figure 8) than when the axis of the inner coupling member is orthogonal to the axis of the cage (see Figure 9). Figure 10 This is small. Furthermore, by making the diameter E of the cage's cylindrical surface larger than the apparent maximum outer diameter D3 of the inner coupling member when its axis is inclined relative to a plane orthogonal to the cage's axis, the inner coupling member can be fitted into the inner circumference of the cage (see Figure 8). Additionally, by making the diameter E of the cage's cylindrical surface smaller than the apparent maximum outer diameter D1 of the inner coupling member when its axis is orthogonal to the cage's axis, the cage's wall thickness can be ensured while maintaining strength (see Figure 8). Figure 10 ).

[0028] If the axial width of the inner coupling component is too large, then in order to assemble the inner coupling component onto the inner circumference of the cage, the cylindrical surface of the cage needs to be enlarged. Therefore, it is preferable to make the axial width W of the inner coupling component and the diameter D of the balls... BALL ratio W / D BALL Set to 1.74 to 1.99. In particular, when the axial distance W2 between the end face of the inner coupling member on the other axial side and the center of the coupling is greater than the axial distance W1 between the end face of the inner coupling member on one axial side and the center of the coupling, it is preferable to set the axial distance W2 between the end face of the inner coupling member on the other axial side and the center of the coupling and the diameter D of the ball. BALL The ratio of W2 / D BALL Set it to 0.99~1.13.

[0029] For example, by setting the angle α between the axis of the inner coupling member and the axis of the cage to more than three times the inclination angle γ of the plane containing the ball track center lines X and Y of each raceway groove relative to the axial direction, it is possible to make the apparent maximum outer diameter D3 of the inner coupling member smaller than the diameter E of the cylindrical surface of the cage.

[0030] The inclination angle γ of the raceway groove relative to the axial direction is preferably 4° to 8°. This prevents inevitable malfunctions and a decrease in constant velocity of the coupling, and ensures the circumferential wall thickness of the column portion of the cage and the wall thickness of the spherical portion of the inner coupling component, thereby ensuring the strength of the coupling.

[0031] In the aforementioned fixed constant velocity universal coupling, it is preferable to use a ball pitch circle diameter PCD. BALL With the diameter D of the ball BALL PCD BALL / D BALL Set in the range of 3.89 to 4.48.

[0032] Each raceway groove of the outer coupling component can have the following structure (refer to Figure 1 for reference numerals).

[0033] • A second raceway groove 7b having an end that is continuous with one end of the first raceway groove 7a along its axial direction and having a straight ball track centerline Xb.

[0034] • The connection point A between the ball track center line Xa of the first raceway groove 7a and the ball track center line Xb of the second raceway groove 7b is located on the axial side of the coupling center O.

[0035] • The ball track centerline Xb of the second raceway groove 7b is inclined in a manner that approaches the axis of the outer coupling member as it tends to the axial side.

[0036] In this case, each raceway groove of the inner coupling component has the following structure (refer to Figure 1 for reference numerals).

[0037] • A second raceway section having a continuous end on the axial side of the first raceway section and having a straight ball track centerline Yb.

[0038] • The connection point B between the ball track centerline Ya of the first raceway groove and the ball track centerline Yb of the second raceway groove is located on the opposite side of the axial direction from the center O of the coupling.

[0039] • The ball track centerline Yb of the second raceway groove is inclined in such a way that it approaches the axis of the inner coupling component as it tends to the other side of the axis.

[0040] By providing the aforementioned straight second raceway groove in the raceway grooves of both the outer and inner coupling components, the effective raceway length can be increased, thereby achieving a high operating angle. Furthermore, within the operating angle range, the balls can contact the arc-shaped first raceway groove, thus suppressing torque loss and heat generation within the operating angle range and achieving high efficiency.

[0041] Invention Effects

[0042] As described above, according to the present invention, in a fixed constant velocity universal coupling of raceway cross type, a decrease in the strength of the cage can be avoided. Attached Figure Description

[0043] Figure 1A This is a partial longitudinal sectional view of a fixed constant velocity universal coupling according to an embodiment of the present invention.

[0044] Figure 1B Viewed from the axial direction Figure 1A Front view of a fixed constant velocity universal joint.

[0045] Figure 2A This is a partial longitudinal sectional view of the outer coupling component of the fixed constant velocity universal coupling shown in Figure 1.

[0046] Figure 2B Viewed from the axial direction Figure 1A Front view of the outer coupling component.

[0047] Figure 3A This is a front view of the inner coupling component in Figure 1, viewed from the axial side.

[0048] Figure 3B Observation from the periphery Figure 3A Side view of the inner coupling component.

[0049] Figure 3C Viewed from the other side of the axis Figure 3A Rear view of the inner coupling component.

[0050] Figure 4 It means Figure 1A A partial longitudinal sectional view detailing the raceway groove of the outer coupling component.

[0051] Figure 5 It means Figure 1A A longitudinal sectional view showing the details of the raceway groove of the inner coupling component.

[0052] Figure 6A This is a diagram showing the assembly method of the cage and the inner coupling components. It is a partial longitudinal sectional view viewed from the radial direction of the cage.

[0053] Figure 6B This is a diagram showing the assembly method of the cage and the inner coupling components. It is a front view viewed from the axial direction of the cage.

[0054] Figure 7A This is a diagram showing the assembly method of the cage and the inner coupling components. It is a partial longitudinal sectional view viewed from the radial direction of the cage.

[0055] Figure 7B This is a diagram showing the assembly method of the cage and the inner coupling components. It is a front view viewed from the axial direction of the cage.

[0056] Figure 8A This is a diagram showing the assembly method of the cage and the inner coupling components. It is a partial longitudinal sectional view viewed from the radial direction of the cage.

[0057] Figure 8B This is a diagram showing the assembly method of the cage and the inner coupling components. It is a front view viewed from the axial direction of the cage.

[0058] Figure 9A This is a diagram showing the assembly method of the cage and the inner coupling components. It is a partial longitudinal sectional view viewed from the radial direction of the cage.

[0059] Figure 9B This is a diagram showing the assembly method of the cage and the inner coupling components. It is a front view viewed from the axial direction of the cage.

[0060] Figure 10 This is a front view of the cage from the axial direction, with the cage axis orthogonal to the axis of the inner coupling components.

[0061] Figure 11 It is an enlarged representation Figure 1A A partial longitudinal sectional view of a fixed constant velocity universal joint.

[0062] Figure 12 It is an enlarged representation Figure 1A A partial longitudinal sectional view of a fixed constant velocity universal joint.

[0063] Figure 13A This is a partial longitudinal sectional view of the outer coupling component.

[0064] Figure 13B This is a front view of the outer coupling component assembled with the cage, viewed from the axial direction of the outer coupling component.

[0065] Figure 13C This is the front view of the cage viewed from the axial direction.

[0066] Figure 14A This is a partial longitudinal sectional view of the outer coupling component.

[0067] Figure 14B yes Figure 14A A cross-sectional view at the PP line.

[0068] Figure 15 This is a partial longitudinal sectional view of a fixed constant velocity universal coupling according to another embodiment of the present invention.

[0069] Figure 16A This is a partial longitudinal sectional view of a fixed constant velocity universal coupling according to another embodiment of the present invention.

[0070] Figure 16B yes Figure 16A Enlarged view of the T-section.

[0071] Figure 17A This is a partial longitudinal sectional view of a conventional fixed constant velocity universal coupling (ball cage type).

[0072] Figure 17B Viewed from the axial direction Figure 17AFront view of a fixed constant velocity universal joint.

[0073] Figure 18 Viewed from the axial direction Figure 17A The front view of the inner coupling component of the fixed constant velocity universal joint, and the longitudinal sectional view of the cage.

[0074] Figure 19A This is a partial longitudinal sectional view of a conventional fixed constant velocity universal coupling (raceway groove cross type).

[0075] Figure 19B Viewed from the axial direction Figure 19A Front view of a fixed constant velocity universal joint. Detailed Implementation

[0076] The embodiments of the present invention will be described with reference to the accompanying drawings.

[0077] First, the basic structure of the fixed constant velocity universal joint 1 of the raceway cross type according to this embodiment will be described based on Figures 1 to 5. The fixed constant velocity universal joint 1 mainly includes an outer coupling component 2, an inner coupling component 3, balls 4, and a cage 5.

[0078] Eight raceway grooves 7 are formed on the spherical inner circumferential surface of the outer coupling component 2, and eight raceway grooves 9 are formed on the spherical outer circumferential surface of the inner coupling component 3 (see reference). Figure 1B A spherical portion 6 remains between the raceway grooves 7 on the inner circumferential surface of the outer coupling component 2, and a spherical portion 8 remains between the raceway grooves 9 on the outer circumferential surface of the inner coupling component 3 (see reference). Figure 1A The center of curvature of the spherical portion 6 of the inner circumferential surface of the outer coupling member 2 and the center of curvature of the spherical portion 8 of the outer circumferential surface of the inner coupling member both coincide with the coupling center O. One ball 4 is disposed between each of the radially opposed raceway grooves 7 and 9. The cage 5 has: a spherical outer circumferential surface 12 that engages with the spherical portion 6 of the inner circumferential surface of the outer coupling member 2; a spherical inner circumferential surface 13 that engages with the spherical portion 8 of the outer circumferential surface of the inner coupling member 3; and eight ball pockets 5a, each holding one ball 4. The cage 5 has a pair of annular portions 5b and 5c disposed on both axial sides of the ball pockets 5a, and a column portion 5e connecting the pair of annular portions 5b and 5c axially (see reference). Figure 1B A cylindrical surface 5d centered on the axis NN is provided on the inner circumferential end of the inner circumferential surface of the annular portion 5c, which is one side in the example shown.

[0079] It should be noted that, below, the opening side of the outer coupling component 2, which is cup-shaped in the axial direction ( Figure 1A The right side is called the "coupling opening side", and its opposite side ( Figure 1AThe left side of the coupling is referred to as the "inner side". Furthermore, to accurately describe the inclination, curvature, and other forms and shapes of the raceway grooves 7 and 9, this specification uses the term "ball track centerline". Here, the ball track centerline refers to the trajectory traced by the center of the ball as it moves along the raceway groove. Therefore, the inclination of the raceway groove is the same as the inclination of the ball track centerline; moreover, the arc or straight shape of the raceway groove is the same as the arc or straight shape of the ball track centerline.

[0080] like Figure 1A As shown, the raceway groove 7 of the outer coupling member 2 has a ball track centerline X. Specifically, the raceway groove 7 is composed of a first raceway groove portion 7a with an arc-shaped ball track centerline Xa and a second raceway groove portion 7b with a straight ball track centerline Xb. The center of curvature of the ball track centerline Xa of the first raceway groove portion 7a (i.e., the center of the ball encompassing all the ball track centerlines Xa) is axially offset by f relative to the coupling center O (the intersection of the plane P containing the centers of the 8 balls 4 and the axis NN at the working angle of 0°) towards the coupling opening side. The ball track centerline Xa of the first raceway groove portion 7a and the ball track centerline Xb of the second raceway groove portion 7b are smoothly continuous. That is, the ball track centerline Xb of the second raceway groove portion 7b coincides with the tangent at the coupling opening side end of the ball track centerline Xa of the first raceway groove portion 7a.

[0081] The raceway groove 9 of the inner coupling component 3 has a ball track centerline Y. Specifically, the raceway groove 9 is composed of a first raceway groove portion 9a with an arc-shaped ball track centerline Ya and a second raceway groove portion 9b with a straight ball track centerline Yb. The center of curvature of the ball track centerline Ya of the first raceway groove portion 9a (i.e., the center of the ball encompassing the entire ball track centerline Ya) is axially offset by f relative to the coupling center O towards the inner side of the coupling. The ball track centerline Ya of the first raceway groove portion 9a and the ball track centerline Yb of the second raceway groove portion 9b are smoothly connected. That is, the ball track centerline Yb of the second raceway groove portion 9b coincides with the tangent of the ball track centerline Ya of the first raceway groove portion 9a at the inner end of the coupling.

[0082] The cross-sectional shapes of raceway grooves 7 and 9 are elliptical or pointed arched. Raceway grooves 7 and 9 make contact with ball 4 at a contact angle (approximately 30°–45°), a so-called angular contact. Therefore, ball 4 contacts the side of raceway grooves 7 and 9 slightly away from the bottom of the groove. It should be noted that the cross-sectional shape of raceway grooves 7 and 9 can also be arc-shaped, and the contact between raceway grooves 7 and 9 and ball 4 can be a so-called annular contact.

[0083] As shown in Figures 2 and 3, the raceway grooves 7 and 9 of the outer coupling component 2 and the inner coupling component 3 are inclined circumferentially relative to the axial direction (the NN direction of the coupling axis). Adjacent raceway grooves in the circumferential direction are inclined to opposite sides relative to the axial direction. Opposite raceway grooves 7 and 9 in the radial direction are inclined to opposite sides relative to the axial direction, and a ball 4 is arranged at their intersection.

[0084] The raceway groove 7 of the outer coupling member 2 will be described in detail based on Figure 2. The raceway groove 7 of the outer coupling member 2 is labeled with reference numerals 7A and 7B depending on its inclination direction. Furthermore, when referring to the entire raceway groove of the outer coupling member 2, reference numeral 7 is used; for the first raceway groove portion, reference numeral 7a is used, and for the second raceway groove portion, reference numeral 7b is used. Moreover, when distinguishing raceway grooves with different inclination directions, reference numerals 7A and 7B are used; for each first raceway groove portion, reference numerals 7Aa and 7Ba are used, and for the second raceway groove portions, reference numerals 7Ab and 7Bb are used. The raceway groove of the inner coupling member 3, which will be described later, is labeled with reference numerals in the same manner.

[0085] like Figure 2A As shown, the plane M containing the ball track centerline X of the raceway groove 7A (more specifically, the plane containing the ball track centerline Xa of the first raceway groove portion 7Aa of the raceway groove 7A and its center of curvature) is inclined at an angle γ relative to the coupling axis NN. Furthermore, although the raceway groove 7B adjacent to the raceway groove 7A in the circumferential direction is not shown, the plane containing the ball track centerline X of the raceway groove 7B (more specifically, the plane containing the ball track centerline Xa of the first raceway groove portion 7Ba of the raceway groove 7B and its center of curvature) is inclined at an angle γ relative to the coupling axis NN to the side opposite to the inclination direction of the raceway groove 7A.

[0086] Next, the raceway groove 9 of the inner coupling component 3 will be described in detail based on Figure 3. The raceway groove 9 of the inner coupling component 3 is labeled with reference numerals 9A and 9B due to its different inclination direction. For example... Figure 3BAs shown, the plane Q containing the ball track centerline Y of the raceway groove 9A (more specifically, the plane containing the ball track centerline Ya of the first raceway groove portion 9Aa and its center of curvature) is inclined at an angle γ relative to the coupling axis NN. Furthermore, although the raceway groove 9B adjacent to the raceway groove 9A in the circumferential direction is omitted from the diagram, the plane Q containing the ball track centerline Y of the raceway groove 9B (more specifically, the plane containing the ball track centerline Ya of the first raceway groove portion 9Ba and its center of curvature) is inclined at an angle γ relative to the coupling axis NN to the side opposite to the inclination direction of the raceway groove 9A. With the working angle at 0°, the ball track centerline Y of each raceway groove 9 of the inner coupling member 3, with reference to the plane P containing the coupling center O and orthogonal to the coupling axis NN, is inclined at an angle γ relative to the ball track centerline X of the raceway groove 7 of the outer coupling member 2, which is opposite to it in the radial direction (see reference). Figure 1A It forms a mirror image symmetry.

[0087] based on Figure 4 The details of the raceway groove 7A of the outer coupling component 2 are described below. Figure 4 It is in the above-mentioned Figure 2A A cross-sectional view taken from plane M, showing the centerline X of the ball track in raceway groove 7A. Therefore, strictly speaking, Figure 4 Instead of a longitudinal sectional view of the plane containing the coupling's axis NN, this shows a section tilted at an angle γ. Figure 4 The image shows the raceway groove 7A of the outer coupling component 2, but the raceway groove 7B is only tilted in the opposite direction to the raceway groove 7A. The other structures are the same as the raceway groove 7A, so the description is omitted.

[0088] The raceway 7A is composed of a first raceway section 7Aa with an arc-shaped ball track centerline Xa and a second raceway section 7Ab with a straight ball track centerline Xb. The arc-shaped ball track centerline Xa has a center of curvature offset axially relative to the coupling center O. The straight ball track centerline Xb of the second raceway section 7Ab is smoothly connected to the end of the ball track centerline Xa of the first raceway section 7Aa on the coupling opening side. In the example shown, the connection point A of the ball track centerlines Xa and Xb is located closer to the coupling opening side than the coupling center O. Therefore, the straight ball track centerline Xb approaches the coupling axis NN (see reference) as it moves towards the coupling opening side. Figure 1A The wedge is tilted in a certain way. This ensures the effective raceway length at the maximum working angle and prevents the wedge angle from becoming too large. Figure 1A The diagram is illustrated with the inclination angle γ of raceway grooves 7 and 9 set to 0°.

[0089] like Figure 4As shown, let L be the straight line connecting the connection point A of the ball track centerlines Xa and Xb and the coupling center O. Project it onto the plane M (refer to the plane containing the raceway groove 7A of the ball track centerline X). Figure 2A The axis N'-N' of the coupling is inclined γ relative to the axis NN of the coupling. Let β' be the angle between the perpendicular K from the coupling center O at axis N'-N' and the straight line L. The perpendicular K lies on a plane P that contains the coupling center O at a working angle of 0° and is orthogonal to the coupling axis NN. Therefore, the angle β between the straight line L and the plane P containing the coupling center O at a working angle of 0° and orthogonal to the coupling axis NN is sinβ = sinβ' × cosγ.

[0090] Similarly, based on Figure 5 The details of the raceway groove 9A are explained based on the longitudinal section of the inner coupling component 3. Figure 5 The longitudinal section is within the range described above. Figure 3B A cross-sectional view taken from plane Q, showing the centerline Y of the ball track in raceway groove 9A. Therefore, with... Figure 4 Similarly, strictly speaking, it is not a longitudinal sectional view of the plane containing the axis NN of the coupling, but rather a section shown at an angle γ. Figure 5 The inner coupling component 3 is shown with raceway groove 9A, but raceway groove 9B is only tilted in the opposite direction to raceway groove 9A. The other structures are the same as raceway groove 9A, so the description is omitted.

[0091] The raceway 9A is composed of a first raceway section 9Aa with an arc-shaped ball track centerline Ya and a second raceway section 9Ab with a straight ball track centerline Yb. The arc-shaped ball track centerline Ya has a center of curvature offset axially relative to the coupling center O. The straight ball track centerline Yb of the second raceway section 9Ab is smoothly connected to the inner end of the ball track centerline Ya of the first raceway section 9Aa. In the example shown, the connection point B of the ball track centerlines Ya and Yb is located closer to the inner side of the coupling than the coupling center O. Therefore, the straight ball track centerline Yb approaches the coupling axis NN (see reference) as it moves towards the inner side of the coupling. Figure 1A The wedge is tilted in a manner that ensures the effective raceway length at the maximum working angle and prevents the wedge angle from becoming excessive. As described above, Figure 1A The diagram is illustrated with the inclination angle γ of raceway grooves 7 and 9 set to 0°.

[0092] like Figure 5 As shown, the straight line connecting point B of the ball track centerlines Ya and Yb and the coupling center O is set as R. The plane Q (referring to the plane containing the raceway groove 9A of the ball track centerline Y) is projected onto the plane containing the raceway groove 9A. Figure 3B Let the axis N'-N' of the coupling be inclined γ relative to the axis NN of the coupling. Let the angle between the perpendicular line K at the center O of the coupling (axis N'-N') and the straight line R be β'. The perpendicular line K lies on a plane P containing the center O of the coupling and orthogonal to the axis NN of the coupling, with a working angle of 0°. Therefore, the angle β between the straight line R and the plane P containing the center O of the coupling and orthogonal to the axis NN of the coupling is sinβ = sinβ' × cosγ.

[0093] Next, the angle β formed by the straight lines L and R relative to the plane P, which includes the coupling center O and is orthogonal to the coupling axis NN, when the working angle is 0°, will be explained. When the working angle is θ, the ball 4 moves θ / 2 relative to the plane containing the coupling center O and orthogonal to the axis of the outer coupling member 2 (or the inner coupling member 3). The angle β is determined based on half of the most frequently used working angle, and the range of the raceway groove contacted by the ball 4 is determined within the range of the most frequently used working angle. Here, the most frequently used working angle is defined. First, the common angle of the coupling refers to the working angle generated by a fixed constant velocity universal joint with a drive shaft at the front in a motor vehicle with one passenger on a level and flat road, when turning to a straight-ahead position. The common angle is selected / determined based on the design conditions of each vehicle model. Furthermore, the frequently used working angle does not refer to the high working angle generated by motor vehicles, such as when turning right or left at intersections, but rather to the working angle generated by the fixed constant velocity universal joint in continuously traveling curved roads. This angle is determined based on the design conditions of each vehicle model, but is larger than the commonly used angle. In this embodiment, angle β is set to a range of 8° to 12°. This ensures, in particular, the length of the raceway groove of the outer coupling component, the strength of the coupling, and prevents the generation of abnormal noises.

[0094] Based on the aforementioned angle β, in Figure 4 In the first raceway groove 7Aa, the connection point A between the ball track centerline Xa and the ball track centerline Xb of the second raceway groove 7Ab becomes the center position of the ball when it moves axially to the side closest to the opening during the working angle with high usage frequency. Similarly, in the inner coupling component 3, in Figure 5 In this configuration, the connection point B between the ball track center line Ya of the first raceway groove 9Aa and the ball track center line Yb of the second raceway groove 9Ab becomes the center position of the ball when it moves axially to the innermost side during the most frequently used operating angle. Due to this configuration, within the range of most frequently used operating angles, the ball 4 is located at 7Ba and 9Ba, whose tilt direction is opposite to that of the first raceway grooves 7Aa and 9Aa of the outer coupling member 2 and the inner coupling member 3 (see Figures 2 and 3).

[0095] The overall structure of the fixed constant velocity universal coupling 1 in this embodiment is as described above. Next, using Figures 6- Figure 11 The sequence in which the inner coupling component 3 is inserted into the inner circumference of the opposing cage 5 will be explained.

[0096] First, as shown in Figure 6, with the axis of the inner coupling member 3 approximately orthogonal to the axis of the cage 5, a portion of the inner coupling member 3 is inserted into the inner circumference of the cage 5 from the coupling opening side (cylindrical surface 5d side). Furthermore, any one of the raceway grooves 9 of the inner coupling member 3... Figure 6A The lower end of the raceway groove (also referred to as "raceway groove 90") is fitted from the inner circumferential side into the annular portion 5c on the coupling opening side of the cage 5. In this embodiment, as... Figure 6B As shown, the axis of the inner coupling member 3 is slightly inclined relative to the direction orthogonal to the axis of the cage 5. Specifically, the axis of the inner coupling member 3 is inclined approximately at the inclination angle γ of the raceway groove 9 (refer to...). Figure 3B The amount of ) . As a result, the extending direction of the raceway groove 90 (the center line X of the ball track) is approximately orthogonal to the axial direction of the cage 5, and is arranged approximately parallel to the annular portion 5c of the cage 5.

[0097] Then, with the engagement portion C of the raceway groove 90 and the annular portion 5c of the cage 5 as the center, the inner coupling member 3 is rotated counterclockwise in the figure (see figure). Figure 6A (The arrow indicates that the inner coupling member 3 is moved towards the inner circumference (inner side of the coupling) of the cage 5. Furthermore, as shown in Figure 7, the inner coupling member 3 has a raceway groove 90 and a raceway groove with a phase difference of 180 degrees (…). Figure 7A The raceway groove at the upper end, also referred to as "raceway groove 91") is disposed on the inner circumference of the annular portion 5c of the cage 5.

[0098] At this time, as Figure 7B As shown, the adjacent raceway grooves 9 of the inner coupling member 3 are inclined to opposite sides relative to the axial direction, thereby narrowing the circumferential width of the spherical surface 8 formed between the adjacent raceway grooves 9 as it tends towards one side or the other side of the axial direction. Therefore, from the axial direction of the cage 5 ( Figure 7B When observing the inner coupling component 3 from the orthogonal direction of the paper, the apparent outer diameter becomes uneven. Specifically, as... Figure 10As shown, with the phase of the inner coupling member 3 adjusted such that the axis of the inner coupling member 3 is orthogonal to the axis of the cage 5 and the phase difference between the two raceway grooves 90 and 91 of the inner coupling member 3 is 180 degrees, and the cylindrical surface 5d of the inner circumferential surface of the cage 5 is opposite to it, when the inner coupling member 3 is viewed from the axial direction of the cage 5, the apparent outer diameter D1 of the inner coupling member 3 at the wider circumferential width of the spherical part 8 is larger than the apparent outer diameter D2 of the inner coupling member 3 at the narrower circumferential width of the spherical part 8 (D1 > D2). In the example shown in the figure, Figure 10 In the state shown, the apparent maximum outer diameter (≈D1) of the inner coupling member 3 is larger than the diameter E of the cylindrical surface 5d of the cage 5. In this case, if the inner coupling member 3 is moved directly in parallel to the inside of the coupling, the inner coupling member 3 and the cage 5 will interfere with each other.

[0099] Therefore, as Figure 8A As indicated by arrow J, the inner coupling component 3 is positioned around a central axis S that is orthogonal to both the axis of the inner coupling component 3 and the axis of the cage 5. Figure 8A The inner coupling component 3 is rotated (up and down) so that its axis is tilted at an angle α relative to the plane orthogonal to the axis of the cage 5. At this time, the two raceway grooves 90 and 91 of the inner coupling component 3, which are 180 degrees out of phase, remain opposite to the cylindrical surface 5d of the inner circumferential surface of the cage 5. Therefore, it is possible to rotate the inner coupling component 3 (up and down) so that its axis is tilted at an angle α relative to the plane orthogonal to the axis of the cage 5. Figure 8B When observing the inner coupling member 3 from the orthogonal direction of the paper, the apparent maximum outer diameter D3 of the inner coupling member 3 is smaller than the diameter E of the cylindrical surface 5d of the cage 5. For example, by making the angle α between the axis of the inner coupling member 3 and the axis of the cage 5 more than three times the inclination angle γ of the raceway groove 9 relative to the axis, the apparent maximum outer diameter D3 of the inner coupling member 3 can be made smaller than the diameter E of the cylindrical surface 5d of the cage 5. However, if the angle α is too large, the apparent maximum outer diameter of the inner coupling member 3 will actually increase. Therefore, the angle α is preferably set to minimize the apparent maximum outer diameter of the inner coupling member 3.

[0100] In this state, such as Figure 9A As indicated by arrow I, the inner coupling member 3 is moved inwards towards the inside of the coupling, and the inner coupling member 3 is moved in the direction of arrow J' (in line with...). Figure 8A Rotate the inner coupling member 3 (in the opposite direction of arrow J) to engage the spherical surface 8 of the inner coupling member 3 with the spherical inner circumferential surface 13 of the cage 5. Then, rotate the inner coupling member 3 further relative to the cage 5 so that the axis of the inner coupling member 3 is aligned with the axis of the cage 5, thereby completing the assembly of the two.

[0101] As described above, even if the diameter E of the cylindrical surface 5d of the cage 5 is smaller than that of the cage 5, Figure 10 As shown in Figure 8, when the apparent maximum outer diameter D1 of the inner coupling member 3 is viewed orthogonally to the plane of the paper, by tilting the axis of the inner coupling member 3 relative to the plane orthogonal to the axis of the cage 5, the apparent maximum outer diameter D3 of the inner coupling member 3 can be made smaller than the diameter E of the cylindrical surface 5d of the cage 5, thereby allowing the inner coupling member 3 to be installed into the inner circumference of the cage 5. Therefore, the diameter E of the cylindrical surface 5d of the cage 5 can be made smaller than the apparent maximum outer diameter D1 of the inner coupling member 3 when viewed orthogonally to the plane of the paper in Figure 9, thereby ensuring the radial wall thickness of the annular portion 5c of the cage 5 and maintaining the strength of the cage 5.

[0102] In addition to the above, the fixed constant velocity universal coupling 1 of this embodiment also has the following structure.

[0103] (1) The axial width W of the inner coupling component and the diameter D of the ball bearing BALL ratio W / D BALL The value ranges from 1.74 to 1.99.

[0104] (2) The axial distance W2 between the inner end face of the coupling component and the center of the coupling, and the diameter D of the balls. BALL The ratio of W2 / D BALL The value ranges from 0.99 to 1.13.

[0105] If the axial width W of the inner coupling component 3 is increased (refer to...) Figure 3B The spherical part 8 extends axially. Therefore, as shown in FIG8, even if the axis of the inner coupling member 3 is tilted relative to a plane orthogonal to the axis of the cage 5, it is sometimes impossible to make the apparent maximum outer diameter D3 of the inner coupling member 3 smaller than the diameter E of the cylindrical surface 5d of the cage 5. In this case, it is necessary to increase the diameter of the cylindrical surface 5d of the cage 5, which leads to a decrease in the strength of the cage 5. Therefore, the axial width W of the inner coupling member 3 is preferably suppressed to below a predetermined value. In particular, as in this embodiment, when the axial distance W2 between the inner end face of the inner coupling member 3 and the coupling center O is greater than the axial distance W1 between the inner end face of the inner coupling member 3 and the coupling center O, it is preferable to suppress the axial distance W2 between the inner end face of the inner coupling member 3 and the coupling center O to below a predetermined value.

[0106] On the other hand, if the axial width W of the inner coupling component 3 is too small, the raceway length becomes too short, making it difficult to ensure the contact point between the balls 4 and the raceway grooves 7 and 9 at high operating angles, resulting in a significant reduction in functionality at high angles. Therefore, the axial width W of the inner coupling component 3, and especially the axial distance W2 between the inner end face of the inner coupling component 3 and the coupling center O, is preferably a specified value or higher.

[0107] (3) Pitch circle diameter PCD of the ball BALL With the diameter D of the ball BALL PCD BALL / D BALL The range is 3.89 to 4.48.

[0108] like Figure 11 As shown, the pitch circle diameter PCD of the ball... BALL It is the pitch circle diameter between the centers of the plurality of balls 4 arranged on the center O of the coupling; more specifically, it is the diameter of the ball along the center lines Xa and Ya of the ball track, which includes all the raceway grooves 7 and 9. The fixed constant velocity universal coupling 1 of this embodiment uses the diameter D of the balls... BALL The pitch circle diameter (PCD) of the ball as a reference BALL PCD BALL / D BALL Set in the range of 3.89 to 4.48. Figure 11 The diagram is illustrated with the inclination angle γ of raceway grooves 7 and 9 set to 0°.

[0109] With the diameter D of the ball BALL The pitch circle diameter (PCD) of the ball as a reference BALL The ratio of PCD BALL / D BALL When the value is less than 3.89, the diameter D of the ball is... BALL Relative to the pitch circle diameter PCD of the ball BALL The diameter of the balls 4 becomes too large, so the circumferential distance between their outer diameters becomes closer, and the circumferential width F of the spherical surface 8 between the raceway grooves (refer to...) Figure 3C ), the column portion 5e of the cage 5 (refer to) Figure 1B The cross-sectional area of ​​the ball bearings becomes smaller, making it impossible to ensure the strength of each component. Alternatively, due to the reduced pitch circle diameter (PCD) of the balls... BALL Relative to the diameter D of the ball BALL If the size is too small, the load distributed among each ball 4 will increase, making it impossible to ensure the strength of each component.

[0110] On the other hand, with the diameter D of the ball... BALL The pitch circle diameter (PCD) of the ball as a reference BALL The ratio of PCD BALL / D BALL When the value is greater than 4.48, the diameter D of the ball is... BALL Relative to the pitch circle diameter PCD of the ball BALL If the diameter is too small, the contact pressure between the raceway grooves 7 and 9 and the ball 4 becomes too large relative to the input torque, compromising durability. Alternatively, the contact pressure relative to the ball diameter D... BALL The pitch circle diameter (PCD) of the ball bearing BALLIt becomes too large, so the outer diameter of the outer coupling component 2 becomes larger, making it impossible to maintain compactness.

[0111] (4) The axial offset f between the center O of the coupling and the center of curvature of the arc-shaped ball track and the pitch circle diameter PCD of the ball. BALL The ratio f / PCD BALL It is 0.009.

[0112] like Figure 12 As shown, in this embodiment, the center of curvature of the ball track centerline Xa of the first raceway groove 7a of the raceway groove 7 of the outer coupling member 2 (hereinafter referred to as "outer raceway center Oo1") and the center of curvature of the ball track centerline Ya of the first raceway groove 9a of the raceway groove 9 of the inner coupling member 3 (hereinafter referred to as "inner raceway center Oi1") are offset axially to opposite sides relative to the coupling center O (this axial offset is referred to as "offset f"). In addition, in this embodiment, a structure is illustrated in which the outer raceway center Oo1 is arranged on the coupling opening side and the inner raceway center Oi1 is arranged on the inner side of the coupling relative to the coupling center O, but it is also possible to arrange the outer raceway center Oo1 on the inner side of the coupling and the inner raceway center Oi1 on the coupling opening side relative to the coupling center O.

[0113] If the outer raceway center Oo1 and the inner raceway center Oi1 are offset as described above, a force is generated during torque transmission, causing the balls 4 to press against the cage 5. In this case, friction is generated at the contact points between the spherical inner circumferential surface (spherical part 6) of the outer coupling member 2 and the spherical outer circumferential surface 12 of the cage 5, and between the spherical outer circumferential surface (spherical part 8) of the inner coupling member 3 and the spherical inner circumferential surface 13 of the cage 5, thus causing energy loss corresponding to this friction. However, on the other hand, if the outer raceway center Oo1 and the inner raceway center Oi1 are unintentionally offset relative to the coupling center O, the direction of the offset of the outer raceway center Oo1 and the inner raceway center Oi1 relative to the coupling center O becomes random, which may cause functional deviation. Therefore, it is preferable to offset the outer raceway center Oo1 and the inner raceway center Oi1 in opposite axial directions relative to the coupling center O with an energy loss level that will not be a practical problem. Therefore, focusing on the offset angle of 1°, the offset amount f is compared with the pitch circle diameter PCD of the ball. BALL The ratio f / PCD BALL The upper limit is set to 0.009. On the other hand, considering the offset angle of 0.02° that produces the effect of offset, it will be higher than f / PCD. BALL The lower limit is set to 0.0002.

[0114] In the example shown, the center of curvature of the spherical part 6 of the inner circumferential surface of the outer coupling member 2, i.e., the center of curvature of the spherical outer circumferential surface 12 of the cage 5 (hereinafter referred to as "cage outer spherical center Oc1"), and the center of curvature of the spherical part 8 of the outer circumferential surface of the inner coupling member 3, i.e., the center of curvature of the spherical inner circumferential surface 13 of the cage 5 (hereinafter referred to as "cage inner spherical center Oc2"), both coincide with the coupling center O. That is, the axial offset of the cage outer spherical center Oc1 and the cage inner spherical center Oc2 relative to the coupling center O (hereinafter referred to as "cage offset f2") is 0. In this case, the offset f is equal to the axial offset of the outer raceway center Oo1 and the inner raceway center Oi1 relative to the cage outer spherical center Oc1 and the cage inner spherical center Oc2 (hereinafter referred to as "raceway offset f1"). In this way, by setting the cage offset f2 to 0, the wall thickness in the radial direction of the cage 5, and more specifically the radial distance between the spherical outer circumferential surface 12 and the spherical inner circumferential surface 13, becomes uniform, thus ensuring the strength of the cage.

[0115] (5) Diameter D of the inlet fitting part of the outer coupling component INLET With the diameter D of the ball BALL The ratio of D INLET / D BALL The values ​​range from 4.18 to 4.76.

[0116] In a fixed constant velocity universal coupling with a cross-type raceway groove, the raceway grooves are inclined circumferentially relative to the axis of the coupling, and the inclination direction is opposite to that of adjacent raceway grooves in the circumferential direction. Therefore, there are large and small portions of spherical width (circumferential width of the spherical surface between the raceway grooves) between the raceway grooves on the open end side of the outer coupling member.

[0117] like Figure 13B As shown, with the axis of the retainer 5 orthogonal to the axis of the outer coupling member 2, the retainer 5 is inserted into the inner circumference of the outer coupling member 2. At this time, the retainer 5 can be inserted from a position where the spherical width W4 of the outer coupling member 2 is smaller than the window width W3 of the ball pocket 5a of the retainer 5. Furthermore, Figure 13A The diameter D of the inlet fitting portion of the outer coupling component 2 shown is... INLET It needs to be set to be greater than that. Figure 13C The window height H is determined by the window length W5 of the cage 5 shown.

[0118] like Figure 13A As shown, at the inlet fitting portion, diameter D INLET With the diameter D of the ball BALL The ratio of D INLET / D BALLWhen the value is less than 4.18, in order to insert the retainer 5 into the outer coupling member 2, the window length W5 of the retainer 5 needs to be increased (the window height H needs to be reduced), but the circumferential length of the retainer column 5e becomes smaller, making it difficult to ensure the strength of the retainer 5. On the other hand, when the value is less than D... INLET / D BALL When the angle is greater than 4.76, the contact area becomes smaller when the spherical inner circumferential surface of the outer coupling member 2 contacts the spherical outer circumferential surface 12 of the cage 5 at high operating angles. This results in increased surface pressure and reduced durability.

[0119] In this embodiment, the fixed constant velocity universal coupling 1 has an inlet fitting portion diameter D of the outer coupling component 2. INLET With the diameter D of the ball BALL The ratio of D INLET / D BALL The value is set within the range of 4.18 to 4.76. This ensures the strength of the cage 5, suppresses the contact surface pressure between the spherical inner circumferential surface of the outer coupling member 2 and the spherical outer circumferential surface 12 of the cage 5 at high operating angles, and ensures durability.

[0120] (6) The plane containing the ball track centerline of the first raceway groove and the coupling center O is inclined at an angle γ of 4° to 8° relative to the coupling axis NN.

[0121] The inclination angle γ of the first raceway grooves 7a and 9a relative to the axial direction (refer to...) Figure 2A and Figure 3B When the angle is less than 4°, the force controlling the balls at the cross angle (2γ) decreases, resulting in unavoidable malfunctions and reduced speed uniformity of the coupling. On the other hand, when the inclination angle γ of the first raceway grooves 7a and 9a relative to the axial direction is greater than 8°, the circumferential movement of the balls at the working angle increases, and the column portion 5e of the cage 5 (refer to...) Figure 1B The circumferential wall thickness of the inner coupling component 3 and the circumferential width F of the spherical part 8 (refer to) Figure 3C (Insufficient) strength cannot be guaranteed.

[0122] In this embodiment, the fixed constant velocity universal joint 1 sets the inclination angle γ of the first raceway groove portions 7a and 9a relative to the axial direction to a range of 4° to 8°. This prevents unavoidable malfunctions and a decrease in constant velocity, ensures the circumferential wall thickness of the cage column portion and the wall thickness of the spherical portion of the inner coupling component, and guarantees the strength of the coupling.

[0123] (7) Outer diameter D of the outer coupling component OUTER With the pitch circle diameter PCD of the ball BALL The ratio of D OUTER / PCD BALLIt ranges from 1.34 to 1.44.

[0124] Figure 14 shows the outer diameter D of the outer coupling component 2. OUTER The pitch circle diameter (PCD) of the ball bearing BALL The outer diameter D of the outer coupling component. OUTER With the pitch circle diameter PCD of the ball BALL The ratio of D OUTER / PCD BALL When the value is less than 1.34, the wall thickness of the outer coupling component 2 becomes too small, making it difficult to ensure the strength of the outer coupling component 2. In the case of D... OUTER / PCD BALL When the thickness is greater than 1.44, the wall thickness of the outer coupling component 2 becomes too large, thus increasing the weight and making it difficult to achieve a lightweight and compact design.

[0125] In this embodiment, the fixed constant velocity universal coupling 1 connects the outer diameter D of the outer coupling component 2. OUTER With the pitch circle diameter PCD of the ball BALL The ratio of D OUTER / PCD BALL The value is set within the range of 1.34 to 1.44. This ensures the strength of the outer coupling component 2 and achieves a lightweight and compact design.

[0126] This invention is not limited to the embodiments described above. Other embodiments of the invention will be described below, but repeated descriptions of points identical to those described above will be omitted.

[0127] In the above embodiments, it is shown that the raceway grooves 7 and 9 are composed of first raceway groove portions 7a and 9a having arc-shaped ball track center lines Xa and Ya and second raceway groove portions 7b and 9b having straight ball track center lines Xb and Ya. However, it is not limited to this. For example, the raceway grooves 7 and 9 may be formed only by the first raceway groove portions having arc-shaped ball track center lines Xa and Ya.

[0128] In the above embodiments, a case is shown where the cage offset f2 is 0 and the offset f is equal to the raceway offset f1, but this is not the only possibility. For example, in Figure 15 In the illustrated embodiment, by aligning the outer raceway center Oo1 with the cage outer spherical center Oc1 and the inner raceway center Oi1 with the cage inner spherical center Oc2, the raceway offset f1 is set to 0. In this case, the offset f is equal to the cage offset f2. Thus, by setting the raceway offset f1 to 0, the depths of the first raceway grooves 7a and 9a can be made uniform, thereby preventing a decrease in durability caused by the upward movement of the balls 4 into the first raceway grooves 7a and 9a. Furthermore, Figure 15The diagram is illustrated with the inclination angle γ of raceway grooves 7 and 9 set to 0°.

[0129] Alternatively, as shown in Figure 16, both raceway offset f1 and cage offset f2 can be assigned. In this case, the outer raceway center Oo1 and the cage outer spherical center Oc1 are offset in the same axial direction (in the example, the coupling opening side) relative to the joint center O, and the inner raceway center Oi1 and the cage inner spherical center Oc2 are offset in the same axial direction (in the example, the inner side of the coupling) relative to the joint center O. The sum of the raceway offset f1 and the cage offset f2 is the offset f (f = f1 + f2). Furthermore, Figure 16 illustrates the state with the inclination angle γ of raceway grooves 7 and 9 set to 0°.

[0130] Alternatively, if there is no malfunction in the coupling, the raceway offset f1 and the cage offset f2 can both be set to 0, and the offset f can be set to 0.

[0131] This invention is not limited to any of the above-described embodiments. It can be implemented in various ways without departing from the spirit of the invention. The scope of the invention is shown by the technical solutions, and also includes the equivalent meanings described in the technical solutions and all modifications within the scope.

[0132] Explanation of reference numerals in the attached figures

[0133] 1. Fixed constant velocity universal joint

[0134] 2. Outer coupling components

[0135] 3. Inner coupling components

[0136] 4 ball bearings

[0137] 5. Cage

[0138] 5D cylindrical surface

[0139] 6. Spherical face

[0140] 7. Raceway groove

[0141] 7a First raceway groove

[0142] 7b Second raceway groove

[0143] 8. Sphere

[0144] 9. Raceway groove

[0145] 9a First raceway groove

[0146] 9b Second raceway groove

[0147] 12 Spherical outer circumference

[0148] 13 Spherical inner circumferential surface

[0149] The apparent outer diameters of the inner coupling components D1, D2, and D3

[0150] E is the diameter of the cylindrical surface of the cage.

[0151] O Coupling center X Outer coupling component raceway groove ball track centerline

[0152] Xa Centerline of the ball track in the first raceway groove

[0153] Xb The centerline of the ball track in the second raceway groove

[0154] The centerline of the ball track in the raceway groove of the Y-shaped inner coupling component.

[0155] Ya, the center line of the ball track in the first raceway groove

[0156] Yb The centerline of the ball track in the second raceway groove

[0157] Oo1 Outer raceway center

[0158] Oi1 Inner Ring Raceway Center

[0159] Oc1 Cage outer spherical center

[0160] Oc2 Cage Inner Spherical Center

[0161] f offset

[0162] f1 Roller offset

[0163] f2 is the cage offset.

Claims

1. A fixed constant velocity universal joint, comprising: The outer coupling component has eight raceway grooves formed on its spherical inner circumferential surface; The inner coupling component has eight raceway grooves formed on its spherical outer circumferential surface; Eight balls, sandwiched between the raceway grooves of the outer coupling member and the raceway groove of the inner coupling member, transmit torque; and The cage has a spherical outer peripheral surface that engages with the spherical inner peripheral surface of the outer coupling member, a spherical inner peripheral surface that engages with the spherical outer peripheral surface of the inner coupling member, eight ball pockets each holding one of the ball balls, and a cylindrical surface disposed at the axial end of the inner peripheral surface, wherein... The outer coupling component has a first raceway groove with an arc-shaped ball track centerline (Xa), and the inner coupling component has a first raceway groove with an arc-shaped ball track centerline (Ya). The plane containing the ball track centerline (Xa) of the first raceway groove portion of each raceway groove of the outer coupling member and the plane containing the ball track centerline (Xa) of the first raceway groove portion of the raceway adjacent to each raceway groove are inclined at an angle γ to opposite sides relative to the axial direction. The plane containing the ball track centerline (Ya) of the first raceway groove portion of each raceway groove of the inner coupling component and the plane containing the ball track centerline (Ya) of the first raceway groove portion of the raceway groove adjacent to each raceway groove are inclined at an angle γ to opposite sides relative to the axial direction. The plane containing the first raceway groove portion of the outer coupling member, along with the ball track centerline (Xa), and the plane containing the first raceway groove portion of the inner coupling member, which is radially opposite to the outer coupling member, are inclined to opposite sides relative to the axial direction. The diameter (E) of the cylindrical surface of the cage is smaller than the apparent maximum outer diameter (D1) of the inner coupling member when viewed from the axial direction of the cage, with the axis of the inner coupling member orthogonal to the axis of the cage and the two raceway grooves of the inner coupling member 180 degrees out of phase facing the inner circumferential surface of the cage. The diameter (E) of the cylindrical surface of the cage is larger than the apparent maximum outer diameter (D3) of the inner coupling member when viewed from the axial direction of the cage, with the axis of the inner coupling member tilted at an angle α relative to a plane orthogonal to the axis of the cage and the two raceway grooves of the inner coupling member being 180 degrees out of phase facing the inner circumferential surface of the cage.

2. The fixed constant velocity universal coupling according to claim 1, wherein, The axial width W of the inner coupling component is related to the diameter D of the balls. BALL ratio W / D BALL The value ranges from 1.74 to 1.

99.

3. The fixed constant velocity universal coupling according to claim 1 or 2, wherein, The axial distance W2 between the end face of the inner coupling component on the other axial side and the center of the coupling is greater than the axial distance W1 between the end face of the inner coupling component on one axial side and the center of the coupling. The axial distance W2 between the end face of the inner coupling component on the other side of the axial direction and the center of the coupling, and the diameter D of the ball. BALL The ratio of W2 / D BALL The value ranges from 0.99 to 1.

13.

4. The fixed constant velocity universal joint according to claim 1 or 2, wherein, The angle α is more than 3 times the angle γ.

5. The fixed constant velocity universal joint according to claim 1 or 2, wherein, The angle γ is 4° to 8°.

6. The fixed constant velocity universal joint according to claim 1 or 2, wherein, The pitch circle diameter (PCD) of the ball BALL ) and the diameter (D) of the ball BALL The ratio of PCD BALL / D BALL The range is 3.89 to 4.

48.

7. The fixed constant velocity universal joint according to claim 1 or 2, wherein, In each raceway groove of the outer coupling component, A second raceway section has an end that is continuous with one axial direction of the first raceway section and has a straight ball track centerline (Xb). The connection point (A) between the ball track centerline (Xa) of the first raceway groove and the ball track centerline (Xb) of the second raceway groove is located on the axial side of the coupling center (O). The ball track centerline (Xb) of the second raceway groove (7b) is inclined in such a way that it approaches the axis of the outer coupling member as it tends toward one side of the axial direction. In each raceway groove of the inner coupling component, A second raceway section having a continuous end on the axial side of the first raceway section and having a straight ball track centerline (Yb). The connection point (B) between the ball track centerline (Ya) of the first raceway groove and the ball track centerline (Yb) of the second raceway groove is located on the opposite side of the axial direction from the center (O) of the coupling. The ball track centerline (Yb) of the second raceway groove is inclined in such a way that it approaches the axis of the inner coupling member as it tends to the other side of the axis.

Images