JP4795271B2 - Cage for constant velocity universal joint and assembly method thereof - Google Patents

Description

  The present invention is used in, for example, a power transmission mechanism for automobiles and various industrial machines, and is a constant velocity universal joint cage that is one of the components of a constant velocity universal joint that transmits rotational torque between an outer ring and an inner ring. It relates to the assembly method.

  Constant velocity universal joints are used to transmit torque at a constant angular speed by connecting the rotating shaft on the drive side and the rotating shaft on the driven side in the power transmission system of automobiles and various industrial machines. As the ball type constant velocity universal joint, there are various types such as a Barfield type constant velocity universal joint (BJ), a double offset type constant velocity universal joint (DOJ), and a Lebro type constant velocity universal joint (LJ). The number of torque transmission balls is typically 6 or 8.

  These constant velocity universal joints include an outer ring, an inner ring, a ball, and a cage as main components. A plurality of track grooves extending in the axial direction are formed along the circumferential direction on the inner peripheral surface of the outer ring, and a plurality of track grooves extending in the axial direction are also formed along the circumferential direction on the outer peripheral surface of the inner ring. ing. A driving-side rotating shaft and a driven-side rotating shaft are connected to the outer ring and the inner ring. Each track groove of the outer ring and each track groove of the inner ring make a pair to form a ball track, and the ball is incorporated in each ball track. These balls are housed in pockets formed in the circumferential direction of the cage and are held so as to roll freely.

  Therefore, when torque is transmitted with the joint at an operating angle, the ball is always regulated by the cage so that it is located in a plane that bisects the angle formed by the rotation axis of the outer ring and the rotation axis of the inner ring. Thereby, the constant velocity of the joint is ensured. As described above, the cage, which is one component of the constant velocity universal joint, is incorporated between the outer ring and the inner ring, and is one of the important parts that can withstand a large load and hold the ball on the constant velocity bisector. is there.

  In conventional cages, carburized steel is generally used. After making the material into a barrel-shaped ring with a large central diameter, pockets are formed by window cutting, and after carburizing and quenching, the outer spherical surface and inner The contact surface between the spherical surface and the ball (the peripheral wall surface of the pocket) was finished.

There is an inexpensive press method for windowing of this cage, but it is difficult to process when the material hardness of medium carbon steel or the like is high. Become. Therefore, there is a window extraction process using laser light that is not affected by the material hardness and has a relatively short processing time (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-288266

  By the way, the above-described window extraction processing using laser light is performed by piercing an appropriate point near the center of the inside of the pocket formation planned portion by laser light irradiation, and moving the laser light along the pocket shape starting from that point. The final cut with light is completed.

  However, when the cut by the laser light irradiation approaches the final cut portion, the heat by the laser light irradiation becomes excessive in the vicinity of the final cut portion. As a result, in the final cut portion, the cut is caused by overheating rather than the cut by the laser beam, and the roughness of the cut surface (the peripheral wall surface of the pocket) is increased.

  The cage pocket has a substantially rectangular shape with four corners having an R shape, and is composed of a peripheral wall surface portion opposed in the cage axial direction and a peripheral wall surface portion opposed in the cage circumferential direction. The aforementioned corners are located between the wall surfaces.

  The peripheral wall surfaces facing each other in the cage axial direction are surfaces that restrict the axial movement of the ball and hold the ball in a bisecting plane, and are therefore finished by grinding or cutting after laser processing. When the final cut portion is a peripheral wall surface portion facing in the cage axis direction, the surface roughness is poor, so that it is necessary to increase the machining allowance, which is expensive.

  In addition, when the last cut part of the laser processing is a peripheral wall part facing in the circumferential direction of the cage, since the peripheral wall part is a pillar part located between the pockets, the surface is rough and the concave part is a starting point for damage. This may reduce the strength of the column.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to provide a low-cost and high-strength constant velocity universal joint cage and its assembling method by window cutting using laser light. It is to provide.

  As technical means for achieving the above-mentioned object, the present invention provides a constant velocity universal joint cage in which a plurality of ball storage windows are formed along the circumferential direction of the annular peripheral wall. It is characterized in that it is formed by window cutting using laser light, and the final cut portion by the laser light is a corner portion of the ball storage window and a position that does not interfere with the ball at the circumferentially moving end.

  A cage ball storage window is formed by a window extraction process using a laser beam. That is, an appropriate point near the center of the inside of the window formation scheduled portion is drilled by laser light irradiation, and the laser light is moved along the window shape starting from that point, and the process is completed by the final cut portion by the laser light. In that case, the final cut portion by the laser beam is set to a position that does not interfere with the ball at the corner of the ball storage window and at the circumferentially moving end.

  In this way, the last cut portion by the laser beam is a corner portion of the ball storage window, so that the movement of the ball in the axial direction is restricted and the ball is held in a bisector, that is, facing in the cage axial direction. Since the surface roughness of the peripheral wall surface portion is good, when machining is performed by grinding or cutting after laser processing, the machining allowance can be reduced, and the cost can be reduced. Moreover, since the surface roughness becomes good also about the column part located between windows, ie, the surrounding wall surface part which opposes in a cage circumferential direction, the intensity | strength of a column part is securable.

  Further, it is desirable that the corner portion of the ball storage window located at the final cut portion by the laser beam is thicker in the axial direction and the circumferential direction than other corner portions adjacent in the circumferential direction. If it does in this way, even if surface roughness will worsen in the last cut part, intensity | strength in the corner | angular part can be ensured, without intensity | strength falling.

  Furthermore, it is desirable that the final cut portion of at least one pair of the ball storage windows opposed in the radial direction among the plurality of ball storage windows is formed to be a mirror image symmetrical position in the radial cross section. In this way, when the cage is assembled to the outer joint member of the constant velocity universal joint, it is possible to prevent the final cut portion of the ball storage window from interfering with the inner peripheral surface of the outer ring.

  It should be noted that the mirror image symmetrically formed in the radial cross section may be formed with a minimum of a pair of ball storage windows opposed to each other in the radial direction, and may be a plurality of pairs or all of the ball storage windows. In addition, “mirror symmetry” means, for example, that the image reflected in the mirror is the same as the original figure. Of the final cut portions of the pair of ball storage windows, the final of one ball storage window When the cut portion is copied to the mirror, the image becomes the final cut portion of the other ball storage window.

  The constant velocity universal joint cage configured as described above can be assembled to the outer joint member of the constant velocity universal joint in the following manner.

  When the cage is inserted into the outer joint member in a state in which the cage is rotated 90 ° relative to the axial direction of the outer joint member of the constant velocity universal joint, of the final cut portions of the pair of ball storage windows , In a state where the ball storage window of one final cut portion is inclined toward the outer joint member along the circumferential direction, the opening end portion of the outer joint member is allowed to pass through and contact the inner peripheral surface of the outer joint member, Using this as a fulcrum, it is rotated in the direction in which the ball housing window of the other final cut portion is inserted, and the opening end portion of the outer joint member is passed.

  In this way, when the cage is assembled to the outer joint member of the constant velocity universal joint, the final cut portion of the ball storage window does not interfere with the inner peripheral surface of the outer ring, and the constant velocity universal joint is attached to the outer joint member. The cage can be easily assembled.

  According to the present invention, since the final cut portion by the laser beam is the corner portion of the ball storage window, the surface that restricts the axial movement of the ball and holds the ball on the bisector, that is, the cage shaft Since the surface roughness of the peripheral wall surfaces facing each other in the direction is good, when machining is performed by grinding or cutting after laser processing, a machining allowance can be reduced, and cost can be reduced. Moreover, since the surface roughness becomes good also about the column part located between windows, ie, the surrounding wall surface part which opposes in a cage circumferential direction, the intensity | strength of a column part is securable. As a result, a cage for a constant velocity universal joint having high strength and low cost can be provided.

  Further, when the cage is assembled to the outer joint member of the constant velocity universal joint, the outer joint member extends along the circumferential direction of the ball storage window of one final cut portion of the pair of ball storage windows. Rotate in the direction to insert the ball storage window of the other final cut part with the opening end of the outer joint member passing through the opening end of the outer joint member in contact with the inner peripheral surface of the outer joint member. Assembling the cage to the outer joint member of the constant velocity universal joint without causing the final cut portion of the ball housing window to interfere with the inner peripheral surface of the outer joint member by passing through the opening end of the outer joint member Can be done easily.

  Embodiments of a constant velocity universal joint cage according to the present invention and a method of assembling the cage to an outer joint member of the constant velocity universal joint will be described in detail below.

  As shown in FIG. 1, the constant velocity universal joint includes an outer ring 3 as an outer joint member in which a plurality of track grooves 2 extending in the axial direction are formed at equal intervals in the circumferential direction of the inner spherical surface 1, and the track grooves 2 of the outer ring 3. The inner ring 6 as an inner joint member in which a plurality of track grooves 5 extending in the axial direction in pairs with the outer spherical surface 4 are formed at equal intervals in the circumferential direction, the track groove 2 of the outer ring 3, and the track groove 5 of the inner ring 6 And a cage 8 for holding the balls 7 interposed between the inner spherical surface 1 of the outer ring 3 and the outer spherical surface 4 of the inner ring 6. Each ball 7 is housed in a pocket 9 which is a ball housing window formed in the cage 8 and is arranged at equal intervals in the circumferential direction.

  The constant velocity universal joint is a bar field type (BJ) having an outer ring 3 and an inner ring 6 having track grooves 2 and 5 having a single circular arc surface in the longitudinal direction in the axial direction. Other constant velocity universal joints such as an undercut free type (UJ) having an outer ring and an inner ring having a track groove having a straight bottom parallel to the axial direction may be used.

  A shaft 11 is inserted into the center hole (inner diameter hole) 12 of the inner ring 6 and is spline-fitted, and the torque can be transmitted between the two by the spline fitting. The shaft 11 is prevented from coming off from the inner ring 6 by a retaining ring 13.

Center of curvature O ₂ of the track grooves 5 of the center of curvature O ₁ and the inner ring 6 of the track grooves 2 of the outer ring 3, is offset in the opposite direction in the axial direction by an equal distance f with respect to the joint center O including a ball center O ₃ Yes (track offset). The center of curvature of the inner spherical surface 1 of the outer ring 3 (the outer spherical surface 21 of the cage 8) and the center of curvature of the outer spherical surface 4 of the inner ring 6 (the inner spherical surface 22 of the cage 8) coincide with the joint center O described above. Thus, by providing the track offset, a wedge-shaped ball track is formed with a pair of track grooves 2 and 5 in which the radial interval gradually increases from the back side of the outer ring 3 toward the opening side.

  The cage 8 which is one of the components of the constant velocity universal joint is manufactured in the following manner shown in FIGS.

  First, a barrel-shaped torus material having a large diameter in the central portion in the axial direction is formed. As this torus material, for example, steel having carbon content of 0.4% to 0.55% (carbon steel for mechanical structure JIS G 4051, G 4104) is used.

  Next, the toric material is induction-hardened to produce a hardening material. Here, induction hardening is performed by causing induction current to be generated on the surface portion of the derivative (workpiece) by flowing a high frequency to generate heat, and the surface of the work piece is rapidly heated by this heat for quenching. Is the method. Under the present circumstances, the hardening process raw material has the hardened layer formed in the whole surface, ie, an internal-diameter surface, an outer-diameter surface, and both axial direction end surfaces.

  Since the hardening treatment material is induction hardened, the core can be made harder than carburized and hardened. This improves the durability and strength associated with wear of the outer and inner spherical surfaces. As described above, the constant velocity universal joint can be made compact by improving the strength. Further, the use of steel having a carbon content of 0.4% to 0.55% as the material of the hardening treatment material can further increase the strength. Furthermore, it is more preferable to use spring steel in order to increase the strength.

  In addition, induction hardening can be performed in-line, and production efficiency can be improved. Further, since the quenching is performed before the window cutting process, the shape of the quenching can be simplified, and the quenching can be easily performed in a short time.

  Thereafter, as shown in FIGS. 2A and 2B, the cage 8 is manufactured by window-cutting the pocket 9 with respect to the cured material by the laser processing machine 23. Here, the laser processing machine 23 includes a laser oscillator (not shown) and a torch 24 that irradiates a laser beam from the laser oscillator toward the curing material, and the laser beam from the torch 24 is a pocket of the curing material. Window cutting is performed by irradiating the part to be formed. Thus, the cage 8 having the eight pockets 9 is manufactured at a predetermined pitch (45 ° pitch in the case of a constant velocity universal joint of eight balls) along the circumferential direction of the annular peripheral wall 25.

  The pocket 9 of the cage 8 has a substantially rectangular shape with four corners 9a having an R shape, and includes a peripheral wall surface portion 9b facing in parallel in the cage axial direction and a peripheral wall surface portion 9c facing in the cage circumferential direction. The aforementioned corner portion 9a is located between the two peripheral wall surface portions 9b and 9c adjacent to each other. Thus, the pocket 9 has a circumferentially symmetrical shape having a maximum working angle or a circumferential length that does not hinder the circumferential movement of the ball 7 when the ball is incorporated, a curved shape of the circumferential wall portion 9c, and an R shape of the corner portion 9a. .

  On the other hand, when the pocket 9 of the cage 8 is formed by windowing with a laser beam, as shown in FIG. 3, an appropriate point A closer to the inner center of the portion where the pocket is to be formed is drilled by laser beam irradiation. The laser beam is moved along the pocket shape starting from (see FIG. 2A), and the final cut portion B is completed by the laser beam.

The specific window cutting process by this laser light is performed with a radius of curvature R ₂ smaller than the radius of curvature R ₁ of the peripheral wall surface portion 9 c from the drilled starting point A to one peripheral wall surface portion 9 c opposed in the circumferential direction of the cage. Cutting is performed with the radius of curvature R ₁ from the time when the one peripheral wall surface portion 9c is reached to the next corner portion 9a.

Thereafter, the corner portion 9a and cut with a radius of curvature R _3, cut straight to one of the peripheral wall surface 9b facing cage axis direction along the cage circumferential direction, the next corner portion 9a radius of curvature R ₃ and the other peripheral wall surface portion 9c opposed cage circumferential direction at a radius of curvature R _1, the next corner portion 9a radius of curvature R _3, along the other wall surface portion 9b facing cage axis direction in the cage circumferential direction And cut straight. And let the last cut part B by a laser beam be the position which does not interfere with the ball | bowl 7 in the first corner | angular part 9a drilled, and the circumferential direction movement end.

Here, the broken line in the figure indicates the ball position that is in contact with the circumferential wall surface portion 9c facing in the circumferential direction of the cage and located at the circumferentially moving end (the distance L at which the ball center O ₃ is separated in the circumferential direction of the cage is the ball position). This is a position where the outer side area m of the ball position at the corner 9a does not interfere with the ball 7 at the circumferential movement end.

  Thus, by making the last cut portion B by the laser beam the corner portion 9a of the pocket 9, the surface of the ball 7 that restricts the movement of the ball 7 in the axial direction and holds the ball 7 in a bisector, that is, the cage axial direction Since the surface roughness of the peripheral wall surface portion 9b facing each other is good, the machining allowance can be reduced and the cost can be reduced when finishing by grinding or cutting after laser processing. Moreover, since the surface roughness is good also about the column part 26 (refer FIG. 2 (a) (b)) located between the pockets 9, ie, the surrounding wall surface part 9c which opposes in a cage circumferential direction, column part 26 strength can be ensured.

  Further, the corner portion 9a of the pocket 9 located at the final cut portion B by the laser beam is thicker in the axial direction and the circumferential direction than the other corner portion 9a adjacent in the circumferential direction. Thereby, even if the surface roughness is deteriorated in the final cut portion B, the strength at the corner portion 9a can be ensured without decreasing the strength.

  As for the final cut portion B formed by the laser beam in this way, as shown in FIG. It is formed so as to be a mirror image symmetry position X [indicated by a broken line in FIG. Accordingly, as will be described later, when the cage 8 is assembled to the outer ring 3 of the constant velocity universal joint, it is possible to prevent the final cut portion B of the pocket 9 from interfering with the inner spherical surface 1 of the outer ring 3.

  In addition, it is sufficient to form the pair of pockets 9 that are opposed to each other in the radial direction at the minimum, and the plurality of pairs or all the pockets 9 may be formed at the mirror image symmetry position X in the radial cross section. Further, the mirror image symmetry position X means that when the final cut portion B of one pocket 9 out of the last cut portions B of the pair of pockets 9 opposed in the radial direction is reflected in a mirror, the image of the other pocket 9 It is to become the final cut part B.

  The cage 8 having the above structure can be assembled to the outer ring 3 of the constant velocity universal joint in the following manner shown in FIGS.

  First, as shown in FIG. 4, a pair of pockets 9 at the mirror image position X in the cage 8 in a state where the cage 8 is disposed relative to the axial direction of the outer ring 3 of the constant velocity universal joint in a direction rotated by 90 °. In the final cut portion B [see FIGS. 2 (a) and 2 (b)], the pocket 9 of one final cut portion B is inserted while being inclined toward the outer ring along the circumferential direction. Then, as shown in FIG. 5, one final cut portion B is brought into contact with the inner spherical surface 1 of the outer ring 3 through the opening end of the outer ring 3.

  Then, as shown in FIG. 6, the contact portion Y between the above-mentioned one final cut portion B and the inner spherical surface 1 of the outer ring 3 is used as a fulcrum to rotate in the direction in which the pocket 9 of the other final cut portion B is inserted. The opening end of the outer ring 3 is passed. Finally, as shown in FIG. 7, the entire cage is pushed into the inner side of the outer ring 3, and the cage 8 is rotated by 90 ° with respect to the axial direction of the outer ring 3, so that the cage 8 is moved relative to the outer ring 3. A normal posture is obtained by aligning the axes (see FIG. 1).

  When the cage 8 is assembled to the outer ring 3 of the constant velocity universal joint in this way, the final cut portion B of the pocket 9 does not interfere with the inner spherical surface 1 of the outer ring 3 and the cage to the outer ring 3 of the constant velocity universal joint is obtained. 8 can be easily assembled.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

It is sectional drawing which shows the whole structure of a constant velocity universal joint in embodiment of this invention. It is for demonstrating the pocket formation point of the cage which is a component of the constant velocity universal joint of FIG. 1, (a) is sectional drawing of a cage, (b) is a top view of a cage. FIG. 5 is an enlarged view showing a pocket for explaining a pocket formation procedure of a cage. It is sectional drawing for demonstrating the point which incorporates the cage shown to Fig.2 (a) in an outer ring | wheel. It is sectional drawing for demonstrating the point which incorporates the cage shown to Fig.2 (a) in an outer ring | wheel. It is sectional drawing for demonstrating the point which incorporates the cage shown to Fig.2 (a) in an outer ring | wheel. It is sectional drawing for demonstrating the point which incorporates the cage shown to Fig.2 (a) in an outer ring | wheel.

Explanation of symbols

3 Outer joint member (outer ring)
7 Ball 8 Cage 9 Ball storage window (pocket)
9a Corner 25 Annular wall B Final cut X Mirror position

Claims (4)

  In the constant velocity universal joint cage in which a plurality of ball storage windows are formed along the circumferential direction of the annular peripheral wall, the ball storage window is formed by a window cutting process using a laser beam, and is finally cut by the laser beam. The constant velocity universal joint cage is characterized in that the portion is positioned at a corner of the ball storage window and does not interfere with the ball at the circumferentially moving end.   2. The constant velocity universal joint according to claim 1, wherein a corner portion of the ball storing window positioned at the final cut portion by the laser beam is thicker in the axial direction and the circumferential direction than other corner portions adjacent in the circumferential direction. For cages.   3. The constant velocity according to claim 1, wherein a final cut portion of at least one pair of the ball storage windows opposed in the radial direction among the plurality of ball storage windows is formed to be a mirror image symmetrical position in the radial cross section. Universal joint cage. A plurality of window for ball storage is formed by laser windowing along the circumferential direction of the annular peripheral wall, and the final cut portion by the laser beam is moved at the corner of the ball storage window and in the circumferential direction. By making the position that does not interfere with the ball at the end, the corner of the ball storage window located in the final cut portion is thicker in the axial direction and the circumferential direction than the other corners adjacent in the circumferential direction, A constant-velocity universal joint cage in which the final cut portion of at least one pair of ball storage windows facing each other in the radial direction among the plurality of ball storage windows is formed in a mirror image symmetrical position in the radial cross section is freely adjustable. A method of assembling the outer joint member of the joint,
When the cage is inserted into the outer joint member in a state where the cage is rotated 90 ° relative to the axial direction of the outer joint member, one of the final cut portions of the pair of ball storage windows With the ball storage window of the final cut part tilted toward the outer joint member along the circumferential direction, the opening end of the outer joint member is passed through and brought into contact with the inner peripheral surface of the outer joint member. A method for assembling the cage for a constant velocity universal joint, characterized in that the ball housing window of the other final cut portion is rotated in the insertion direction so as to pass through the opening end portion of the outer joint member.