JPS6124092B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inner ring forming device for a constant velocity universal joint that transmits rotational motion from a drive shaft to a driven shaft at the same angular velocity as the drive shaft.

Generally, as shown in Figures 1 to 3, in a universal joint that uses a ball 3 as an intermediate member for torque transmission between a driving shaft 1 and a driven shaft 2, uniform velocity between both shafts is maintained. In order to achieve this, it is necessary to always maintain the position of the ball 3 on the bisecting plane of the angle formed by the drive shaft 1 and the driven shaft 2. For this purpose, drive shaft 1
It is known that the center of curvature A of the ball groove 6 of the outer ring 5 on the side and the center of curvature B of the ball groove 8 of the inner ring 7 on the driven shaft 2 side can be shifted by an equal distance left and right from the angular center O of the joint. . In this case, the locus of the center point C of the ball rolling in the ball groove is points A and B.
It becomes a curve with the center of curvature at . The angular center O of the joint is the center of the inner spherical surface 9 of the outer ring 5, the outer spherical surface 10 of the inner ring 7, and the inner and outer spherical surfaces of the cage 11 disposed between these spherical surfaces 9 and 10. 7 is always angularly displaced about O via the cage 11. In other words, the angular center O of the joint is always determined at a constant position by the cage 11.

By setting the centers A and B of the ball groove 6 of the outer ring 5 and the ball groove 8 of the inner ring 7 as described above, the distances (offsets) from the angular center O of the joint to A and B, The distances from the ball center C to A and B are both equal, and △OAC and △OBC have three sides that are equal and congruent. Therefore, the distances L ₁ and L ₂ of the ball center C from both axes 1 and 2 are equal, and the ball 3 is always aligned with both axes 1 and 2.
It is controlled on the bisector of the angle formed by This is the same even when the ball is not on the paper, such as the ball in the center of FIG. 3, for example. Therefore, with this type of constant velocity joint, it is possible to maintain constant velocity of both shafts at any operating angle and any rotation angle.

By the way, as mentioned above, this type of constant velocity universal joint has a special design for the shape of the inner and outer rings, so if they were simply manufactured by milling, it would take a lot of time to manufacture, and Because the yield of the materials used was low, it was necessary to go through a special process. For example, in the conventional manufacturing of the inner ring 7, as shown in FIG.
2. This is carried out using a forging die that includes a power punch 13 and a counter punch 14 that cooperate with it. In this case, the portions corresponding to the outer peripheral surface of the inner ring and the portions corresponding to the ball grooves could not be formed into a spherical shape because the punch 13 had to be pulled out upwards, but had to be formed into a substantially straight shape. For this reason, after forging the inner ring material using the forging die, post-cutting processing is performed in which the outer diameter portion and ball groove of the inner ring material are removed by milling or the like in order to finish the respective spherical surfaces. Requires. Moreover,
The post-cutting process also requires a very complicated and inefficient curved cutting process, resulting in long cutting times and poor material yields.

Therefore, the following two methods have been developed to improve and eliminate the disadvantages of manufacturing the inner ring in the conventional constant velocity universal joint described above. Specifically, one of them is, as shown in FIG. 5, by pressing the inner ring material and using a forging die that includes mating dies 15 and 16 having a desired shape to fit therein, a punch 17 and a counter punch 18 that cooperate with the mating dies 15 and 16. I am doing it. With this, it is possible to form a spherical surface, but since the center of the ball groove and the center of the outer diameter spherical surface are offset in the axial direction in the inner ring to be manufactured, the mating mold 15 and 16, and it was impossible to forge the ball groove and the outer spherical surface at the same time. For this reason, if the ball groove is formed by forging, it is necessary to cut the outer diameter spherical surface after forging, and if the outer diameter spherical surface is formed by forging, it is necessary to cut the outer diameter spherical surface after forging. The ball groove required cutting. In addition, since they are mated molds, the centers of the molds 15 and 16 may be misaligned, which may deteriorate precision or cause molds 15 and 1
On the mating surface of No. 6, burrs were generated on the ball groove and the outer spherical surface, which was an obstacle to post-processing.

Next, as shown in FIG. 6, the inner ring material is first formed by a primary forming forging die that includes a die 19 having a desired shape to match the inner ring material, a punch 20 that cooperates with the die 19, and a counter punch 21. The ball groove and the outer diameter spherical surface are each forged into a curved shape with the center of curvature at a predetermined point, and then the molded product obtained by primary forming is adapted to it, as shown in Fig. 7. A secondary forming forging die including a die 22 having a desired shape, a punch 23 and a counter punch 24 cooperating with the die 22 makes the ball groove and the outer diameter spherical surface continuous with the curves described above for approximately the remaining half in the axial direction. It is manufactured by forging into a curved shape. With this, post-cutting processing such as milling can be omitted, and it also prevents a decrease in accuracy of the ball groove due to misalignment in the mating die, and also prevents burrs from occurring during post-processing. Although there were no problems, the ball groove could not completely restrain the primary molded part during secondary molding, resulting in the problem of deformation of the shape, and two forging steps were required.

This invention is intended to improve and eliminate the above-mentioned conventional drawbacks in manufacturing the inner ring of constant velocity universal joints of this type.Hereinafter, an embodiment of the inner ring forming apparatus for a constant velocity universal joint according to the present invention will be described as shown in the drawings. It is as follows.

The inner ring forming device for a constant velocity universal joint according to the present invention is as shown in the embodiment shown in FIGS. 8 and 9, and includes a split die 25 in FIG. A combination die 30 composed of a knockout punch 29
and a means 3 for pushing the combination die 30 downward.
2 and a punch 31
Consists of 3.

The split die 25, which constitutes a part of the combination die 30, has an inner ball groove and an outer diameter spherical surface turned upside down on the inner circumferential surface, and the outer circumferential surface is tapered downward. The ball grooves are formed into equal parts in the circumferential direction (six equal parts in the example shown in the drawings), and the outer circumferential side of each part is guided by a die guide 28, so that when moving up and down, the diameter It has a structure that can be opened and closed in both directions. A split die 25 is vertically slidably inserted into the tapered base 26, and the outer periphery of the die 28 is press-fitted or shrink-fitted with a reinforcing ring 27 so as to withstand the large pressure during molding. The die guide 28 positions the split dies 25 equally on the outer circumferential surface, guides the split dies 25, and opens the split dies 25 in the radial direction by a knockout force. The reinforcing ring 27 fixes the tapered base 26 and the die guide 28 by press-fitting or shrink-fitting them, so that the tapered base 26 and the die guide 28 can withstand the large pressure during molding. The knockout punch 29 is located at the center of the split die 25, and its lower part is held by a pressure receiving plate 34 to form the lower surface of the workpiece under pressure, and also moves in the vertical direction to eject the workpiece.

A positioning means 32 constituting a part of the die set 33 is fixed to a press slide 36 via a cushion 35 made of springs, air, etc., and presses the split die 25 downward to position it in the axial direction before molding the workpiece. Further, the punch 31 is fixed to a press slide 36 so as to be insertable into the split die 25.

The above is the configuration of the inner ring forming device for a constant velocity universal joint according to the present invention.Next, the function and operation of the above configuration will be explained.

First, the material 37 for the inner ring of the constant velocity universal joint is loaded into the split die 25 of the combination die 30, and then the press slide 36 is lowered. Then,
The positioning means 32 pushes the combination die 30 downward and positions it within the die guide 28 and the tapered base 26, and at the same time the punch 31 is inserted into the split die 25, and the knockout punch 2 is inserted into the split die 25.
9, the material 37 is pressed between the split die 2
It is molded into the inner circumferential shape of 5. When the molded product 38 is molded in this manner, the punch 31 is raised by the press slide 36, and at the same time, the knockout punch 29 is pushed upward. Then,
The knock-out force of the knock-out punch 29 causes the molded product 38 to move upward together with the split die 25, and during this upward movement, the split die 25 is opened radially by the taper base 26 and the die guide 28, and the molded product 38 Knock Out Punch 2
9 and is discharged upward.

In the molded product 38 formed in this way, the ball groove, outer diameter spherical surface, and width part are forged at the same time, so the post-processing steps of outer circumference turning, ball groove milling, chamfer milling, and ball groove grinding are omitted. can. This makes it possible to reduce post-process man-hours and at the same time improve material yield by reducing machining allowance. Furthermore, by omitting the ball groove grinding process, in the case of carbon-depleted materials, the time required for de-charcoal heat treatment can be shortened.

As explained above, in this invention, both end faces are parallel end faces orthogonal to the axial direction, the outer diameter face is a spherical face with the center of curvature on the central axis, and the outer diameter face is arranged at equal positions in the circumferential direction of the outer diameter spherical face. The inner ring of a constant velocity universal joint is shaped like an arc with a center of curvature at a position offset on the center axis from the center of curvature of the outer diameter spherical surface, and a ball groove along the axial direction is formed over the entire axial length. It is a device for forging and forming from a raw material, which is equally divided in the circumferential direction and expandable and contractible in the radial direction, and for forming an inner ring that has the same shape as the ball groove and outer diameter spherical surface of the inner ring when the diameter is reduced. It has a split die with a cavity formed on its inner circumferential surface, and a tapered inner circumferential surface that guides and accommodates each split die so that it can slide in the axial direction of the inner ring. A tapered base that expands and contracts the split dies in the radial direction; a die guide that positions and guides each split die at equal circumferential positions within the tapered base; and a die guide that positions and guides each split die at equal circumferential positions within the tapered base; A positioning means for compressing and maintaining the diameter of the split die and a positioning means that are arranged so as to be movable in the axial direction of the inner ring forming cavity formed by the inner circumferential surface of the split die, and the opposing end surfaces are aligned with the respective axes of the inner ring. A pair of punches serve as forming surfaces for the directional end faces, and also compress both ends of the material in the axial direction to cause the material to plastically flow outward in the radial direction to fill the inner ring forming cavity formed by the die. Since the structure is configured, the pair of punches are moved axially close to each other within the cavity formed by the die to compress the material in the axial direction, thereby causing the material to plastically flow radially outward and compressing the material into the cavity. As a result, the inner ring of a constant velocity universal joint, which has a ball groove whose center of curvature is offset in the axial direction and an outer spherical surface, can be formed with high precision in just one forging process. , post-processing such as cutting can be eliminated, and material yield can be improved.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a constant velocity universal joint, and
-Y line sectional view, Figure 2 is a XX line sectional view of Figure 1, Figure 3 is a diagram showing the case where both axes in Figure 1 are angularly displaced, Figures 4 to 7 are conventional A schematic diagram showing an inner ring forming device, FIG. 8 is a longitudinal sectional view showing an inner ring forming device according to the present invention, and FIG.
-Z line sectional view. 25...Split die, 26...Tapered base, 2
7... Reinforcement ring, 28... Dice guide, 29... Knockout punch, 30... Combination die, 32...
Positioning means, 31... Punch, 33... Die set, 36... Press slide, 37... Inner ring material,
38... Molded product.

Claims (1)

[Claims] 1. Both end surfaces are parallel end surfaces perpendicular to the axial direction, the outer diameter surface forms a spherical surface with the center of curvature on the central axis, and the outer diameter surface has a spherical surface at equal positions in the circumferential direction. A device for forging the inner ring of a constant velocity universal joint, which has a circular arc shape with the center of curvature at a position offset from the central axis and a ball groove along the axial direction, formed over the entire axial length, from inner ring material. It is equally divided in the circumferential direction and can be expanded and contracted in the radial direction, and when the diameter is reduced, the inner ring forming cavity having the same shape as the ball groove and the outer spherical surface of the inner ring is formed on the inner peripheral surface. It has a tapered inner circumferential surface that guides and houses each split die in a slidable manner in the axial direction of the inner ring. a tapered base that expands and contracts; a die guide that positions and guides the split dies at equal positions in the circumferential direction within the taper base; A positioning means for maintaining the diameter and a molding surface of each axial end surface of the inner ring are arranged so as to be movable in the axial direction of the inner ring forming cavity formed by the inner peripheral surface of the split die, and the mutually opposing end surfaces are arranged to face each other so as to be movable in the axial direction. and a pair of punches for compressing both ends of the material in the axial direction to cause the material to plastically flow radially outward, filling the inner ring forming cavity formed by the die. Inner ring forming equipment for constant velocity universal joints.