JP3094679B2 - Inner ring forming equipment for constant velocity ball joints - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for forming an inner ring of a constant velocity joint or an intermediate product for an inner ring by forging, and more particularly to forming an inner ring of a constant velocity joint having a ball groove on an outer peripheral surface or an intermediate product thereof. And a device for the same.

[0002]

2. Description of the Related Art In a ball type constant velocity joint, a ball held by a cage called a cage is positioned in a groove of an inner and outer ring, and the center of the groove is equidistant in a direction opposite to the joint center. By offsetting, the ball is maintained on the bisecting plane of the input / output axis, and the uniform velocity is maintained. Because the inner ring and outer ring are irregularly shaped parts,
Conventionally, it is generally manufactured by forging and machining. The present applicant used a forging die for the inner ring as disclosed in Japanese Utility Model Laid-Open No. 3-85.
No. 144 has already proposed this. This is because a plurality of split dies having ridges for forming cross grooves that are alternately inclined in the spiral direction are held at equal intervals on a circumference by a holder, and both sides of the ridges are formed by molding. By providing a restraint that regulates the outer diameter of the product to the outer diameter of the product, by pressing the coarse material in the axial direction with a pair of punches and projecting in the radial direction,
A cross groove is formed, and the shape and the outer diameter are adjusted.

[0003]

The above-described conventional forging die is a forming die for performing closed forging, and therefore, the outer diameter of the molded product does not greatly vary. However, since it will regulate that the material overhangs beyond the product outer diameter, the working pressure must be high, especially in the case of cold forging using high carbon steel as a material, the tendency is remarkable, As a result, there have been inconveniences such as a shortened mold life and a need for a press machine having a large capacity. In addition, since the above-mentioned conventional forging die regulates the overhang of the material to a specified size or more, it is hardly able to absorb the excess thickness, and therefore the volume variation of the coarse material is not allowed. There was an inconvenience requiring a lot of man-hours and labor for management.

On the other hand, it is conceivable to form the inner race of the constant velocity joint by die forging in which the overhang of the material is free to a certain extent. The machining allowance increases, so that machining is increased, and not only the material yield but also productivity may be deteriorated.

[0005] The present invention has been made in view of the above circumstances, the working pressure can be lowered, also it is a child mold the ball groove with high precision, spot volume of the coarse profile is greater
It is an object to provide a equipment to prevent burrs and step occurs in case.

[0006]

SUMMARY OF THE INVENTION The present invention, in order to achieve the above object, a plurality having a collision conditions for cross-groove forming
The inner die for a constant velocity ball joint is formed by distributing the divided dies in the circumferential direction equally on the outer periphery of the crude material and forming the cross groove by pressing the coarse material in the axial direction and projecting to the outer periphery. in the apparatus, prior Symbol ridges in each divided die
Over the entire area of the surface located on both sides in the circumferential direction of the
To set radially outwardly than the outer diameter of the can product
Ri, is relief portion is formed that allows the coarse profile overhangs until the outer diameter larger than the outer diameter of the resulting Rubeki product Rutoto
In addition, a circumferential side edge of the surface portion is formed inside the coarse material.
And it is characterized in that you are sincerely most separated from each other.

[0007]

In the molding apparatus of the present invention, too, a pressure in the axial direction is applied to the rough material to make the rough material protrude to the outer peripheral side.
Since the ridges for forming the cross groove are equally arranged on the outer periphery of the rough material, the ridge portion has a concave shape, and the cross groove is formed here. The flow of the material from which the crude material protrudes to the outer peripheral side is generated toward the side so as to wrap the ridge. A relief portion is formed on the side of this ridge, and the material can overhang to an outer diameter larger than the outer diameter of the product, so that a so-called pressure release state occurs in this portion, so that the processing pressure is low. May be. Accordingly, an excessive load is not applied to the ridge, so that the molding accuracy of the ball groove is improved and the life thereof is also improved . In addition, the face
The circumferential side edge of the furthest away from the center of the
, It is difficult for the crude material to enter the gap between the split dies.
It becomes.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the apparatus of the present invention is substantially an apparatus for performing closed forging. Is pressed by the upper and lower punches 2 and 3 so that the coarsely shaped material 1 protrudes to the outer peripheral side, and the outer shape is given by a plurality of split dies 4. That is, upper punch 2
Are vertically movably inserted into a cylindrical punch holder 5, and the lower punch 3 is a cylindrical split die holder 6 arranged on the same axis as the punch holder 5.
It is arranged to be able to move up and down inside. The punches 2 and 3 have the same outer diameter, and are provided with truncated cone-shaped protrusions at their tip portions.

On the upper surface of the split die holder 6, six projecting guides 7 are provided radially at regular intervals, and the split die 4 is interposed between the guides 7.
Are arranged to be able to move back and forth in the radial direction. A positioning ring 8 that restricts the movement of the split die 4 toward the outer circumference is disposed on the outer peripheral side of the split die 4 so as to be vertically movable. The inner peripheral surface of the tip of the positioning ring 8 is a tapered surface as shown in FIG. 1, while the rear end surface of each split die 4 is an inclined surface corresponding to the inner peripheral surface of the positioning ring 8. Therefore, the taper surface and the inclined surface generate a pressing force toward the center of each split die 4.

Each of the split dies 4 gives the outer shape of the forged product 9, and the shape of the forged product 9 to be obtained is as shown in FIG . That is, in FIG. 3 , reference numeral 10 denotes a cross groove serving as a ball groove for rolling a ball when assembled as a constant velocity joint, and is formed at six locations on the outer periphery of the forged product 9. These cross grooves 1
0 is formed along the helical direction of the outer peripheral surface of the forged product 9 as shown by the respective names, and the adjacent cross grooves 1
The directions of 0 are opposite to each other. Further, the outer peripheral surface portion other than the cross groove 10 has a substantially spherical shape. A total of six split dies 4 are provided, one for each cross groove 10, in order to enable the forged product 9 to be taken out with the cross grooves 10 being alternately opposite in direction. Each split die 4 is provided with a ridge 11 for forming a corresponding cross groove 10.

[0011] The split die 4, ridges 11 of the arc-shaped cross section in front of the base block 12 has an inclined surface to the rear end face, screw
It is formed in the turning direction . This protrusion 11 has a shape corresponding to the shape of the cross grooves 10 to be formed, its ridges 1
1 in the circumferential direction of the positive surface 13 formed on both sides, in the above <br/> downward (the axial direction of Sokatachizai 1) is flattened, and the outer should be obtained as a final product径位It is retracted to the outside further in the radial direction Ri by location.

The front portion 13 is provided with the corresponding split die 4
Formed as a plane perpendicular to the direction of movement (arrow direction)
Have been. In other words, the circumferential side edge of the front portion 13
The part 50 is furthest away from the center of the crude material 1. Soshi
Thus, a relief portion P is formed between the front portion 13 and the coarse material 1.
Is done.

A molding procedure by the above-described apparatus will be described with reference to FIG. First, as shown in FIG. 4A, the upper punch 2, the punch holder 5 and the positioning ring 8 are sufficiently raised, and the lower punch 3 is lowered, and the coarse material 1 is placed on the lower punch 3. Then, when the punch holder 5 and the positioning ring 8 are lowered as shown in (B), the tapered surface of the positioning ring 8 comes into contact with the rear end face of each split die 4 and the position of the split die 4 in the radial direction is determined. And the punch holder 5 clamps the split die 4 between the split die 4 and the split die holder 6. This is a so-called closed state of the mold, and subsequently the upper and lower punches 2 and 3 are brought close to each other to press the coarse material 1 as shown in FIG.

The crude material 1 is compressed in the axial direction,
Since the truncated cone-shaped protrusions provided on the punches 2 and 3 bite, the crude material 1 protrudes in the outer peripheral direction. Since the split dies 4 equally arranged on the outer periphery of the coarse material 1 are fixed by the holders 5 and 6 and the positioning ring 8, the protrusion of the split die 4 is obtained by projecting the rough material 1 to the outer peripheral side. The ridges 11 relatively bite into the outer periphery of the crude material 1, so that the cross grooves 10 are formed. In this way, the excess thickness resulting from the formation of the cross groove 10 flows toward both sides of the ridge 11 in each of the split dies 4, and both sides of the ridge 11 have the outer diameter of the final product as described above. Since the escape portion P is recessed from the position, the flow of the material in this portion is basically not restricted. Therefore, since there is a certain degree of freedom in the material flow, the processing pressure may be lower than that of completely closed forging. Further, since the forming load applied to each of the split dies 4 is reduced and stabilized, the distortion is substantially constant. Therefore, the accuracy of the cross groove 10 is improved, and the life of the mold is prolonged.

If the volume of the rough material 1 is as specified, the portion projecting to the relief portion P has a substantially spherical outer shape due to friction between the mold and the internal friction of the rough material 1. Shape. On the other hand, if the volume of the crude material 1 is larger than the prescribed volume, the amount of protrusion at the relief portion P becomes large.
You. However, the circumferential side edges 5 0 of the front portion 13
However, since it is the most distant from the center of the
Prevents excess material 1 from cutting into gaps between split molds 4
Is done. Therefore, burrs and steps occur in the forged product 9.
Can be avoided, and the forged product 9 is cut in the process of removing excess material
Tooling does not adversely affect the life of the cutting tool.
No.

After the molding is completed as described above, FIG.
(D), the punch holder 5 and the positioning ring 8 are raised to release the fixing of the split die 4, and then the upper punch 2 is raised, and the forged product 9 is pushed up by the lower punch 3 to form the forged product 9. Take out.

Accordingly, in the above-described apparatus, the closed forging apparatus (mold) using the plurality of split dies 4 is used in view of forming the cross grooves 10 which are inclined in the spiral direction and the directions are alternately opposite. Nevertheless, since the relief portion P that allows a part of the material to freely project is provided, the processing pressure can be reduced and the pressure change can be reduced, and the mold can be prevented from being deformed to perform high-precision molding. it can. Even if there are variations in the volume of or coarse profile 1, burrs and stage of forging 9
To avoid the occurrence of differences, it can be kept low at the same time processing pressure.

The escape portion P in the present invention is formed.
The structure for this is not limited to the structure shown in the above embodiment, and may be configured as shown in FIG. That is, FIG. 5 is a diagram showing another example of the escape portion P together, and the example shown by the reference numeral A is a boundary portion between the ridge 11 and the front portion 13 and the outer diameter of the final product. the outer part of the position, to form a curved portion R of the appropriate radius, the curved portion R
This is an example in which a restraining portion 24 is configured by the front portion 13 and the front portion 13 .
The circumferential side edge portion 60 of the front portion 13 is
Most distant from the center of Therefore, the code in FIG.
Even in the portion indicated by A, the volume of the coarse material 1 varies.
Even if there is, the excess thickness of the crude material 1
It is hard to bite in between, and the generation of burrs and steps is suppressed.
In the example of Matako, since overhang of coarse profile 1 is reduced by the restraining portion 24, overhanging coarse profile 1 is suppressed by the resistance force involved.

In the example shown by reference numeral B, a step portion having a predetermined dimension L is provided in the ridge 11 continuously to the radius ro of the cross groove 10, and the step portion is used as a constraint portion 34 . further
In the circumferential direction of the restraining portion 34, the axial direction
A flat front portion 70 is formed.
Is located farthest from the center of the crude material 1.
I'm waiting. In this example, since overhanging material abuts to the restraint portion 34, and is squeezed in the portion exceeding this, deformation resistance is increased by providing the restricting portion 34, excess of Sokatachizai 1 The increase in outer diameter is suppressed. In the case where the restraining portion 34 including the step portion is provided, the shape is given to the forged product 9, so that the chamfering process on the left and right ridge lines of the cross groove 10 which has been conventionally required can be omitted. Note that an appropriate value is selected for the dimension L of the step portion forming the restraining portion 34 depending on the material and shape of the rough material 1. A circumferential side edge portion 71 of the front portion 70 is also provided.
Are most distant from the center of the crude material 1. Accordingly
Therefore, even in the portion indicated by the symbol B in FIG.
Even if there is variation in the product, the excess thickness of the rough material 1 is formed
It is difficult to cut into the gap between the dies 4 and burrs and steps are generated.
Is suppressed.

Furthermore examples of a portion indicated by reference sign C in FIG. 5, the predetermined surface that follows the curved portion R of the radius in the example of the portion of code A described above, with respect to the tangential direction at the end of the curved portion R angle inclined at θ slope (front portion) and 80, an example in which the restraint portion 4 4 these curved portions R Contact and slope 80. In other words, the circumferential side edge of the slope 80
81 is furthest away from the center of the crude material 1. And in this example I but <br/>, overhanging material, these curved portions R
Since squeezed in your Yobihasu surface 80, an excessive increase in the outer diameter can be prevented. Also, the circumferential side edge 81 of the slope 80 is
Since it is the most distant from the center of the crude material 1,
Even in the portion indicated by symbol C, the volume of the crude material 1 varies.
Even if there is, the excess thickness of the rough material 1
It is hard to bite into gaps, and the occurrence of burrs and steps is suppressed
You.

Next, a check was made to confirm the effects of the present invention.
The following shows the measured results. Variation in weight as the coarse material 1
Use a device in the range of about 10 g and use the apparatus shown in FIG.
Performs formed form Te, punch surface pressure and a pitch circle diameter (cross-groove
(The dimension between the centers of curvature). For comparison,
Completely closed by the forging die described in Japanese Utility Model Laid-Open No. 3-85144.
Forging was performed and the same measurement was performed.

FIG. 6 shows the results of measurement of the punch surface pressure.
According to the apparatus of the present invention, the weight (body
Product), the punch surface pressure hardly changes
won. On the other hand, in the conventional forging die, the weight of the
As the volume (volume) increases, the punch contact pressure increases considerably.
Was.

FIG. 7 shows the measurement results of the pitch circle diameter.
As described above, according to the apparatus of the present invention,
The deviation of the pitch circle diameter from the increase in weight (volume) is small.
However, in the conventional forging die, the weight (body
Product) increases the deviation of the pitch circle diameter from the example of the present invention.
And reached several times.

As is apparent from these measurement results,
In the apparatus according to the invention, the allowable width of the variation of the coarse material 1 is wide.
In addition, it is possible to reduce the processing pressure and perform high-precision forging.
it can.

[0025]

As explained above, according to the present invention,
Despite being a device for performing closed forging, a relief is formed on the side of the ridge for the cross groove so as not to particularly restrict the overhang of the coarse material to this part, As the deformation resistance decreases, the working pressure can be reduced, and as a result, not only can the capacity of the press machine be reduced,
High-precision molding can be performed while suppressing distortion of the forging die. Consequently, according to the present invention, it is not necessary or easy to control the dimensions of the coarse material, and the post-cutting can be omitted or reduced, so that the productivity can be improved and the cost can be reduced. . Also, the circle on the front
Circumferential side edges are furthest away from center of coarse material
The excess material of the crude material bites into the gap between the split dies
Is suppressed. Therefore, burrs and
Steps can be avoided and the product can be removed
The cutting tool life when cutting
I will not do it.

[Brief description of the drawings]

1 is a longitudinal sectional view showing an embodiment of the invention of this.

FIG. 2 shows a state at the end of molding in the present invention .
It is a schematic plan view .

FIG. 3 is a perspective view showing an example of a forged product to be obtained.

FIG. 4 is a schematic view showing a forging process using the apparatus of the present invention.

FIG. 5 is an explanatory view showing the shape of a split die according to three other embodiments of the present invention.

FIG. 6 shows a measurement of a punch surface pressure in an example of the present invention and a comparative example.
It is a graph which shows a fixed result .

7 is a graph showing the <br/> measurement results of a pitch circle diameter that put in the present invention and comparative example embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Coarse material 10 Cross groove 11 Ridge 13, 70 Front part 50, 60, 71, 81 Side edge part 80 Slope P Escape part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-142046 (JP, A) JP-A-62-54535 (JP, A) Fully open Flat 3-85144 (JP, U) Really open 108446 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B21K 1/14 B21J 5 / 02,13 / 02

Claims (1)

(57) [Claims] 1. A plurality of distribution with collision conditions for cross-groove forming
An inner ring forming device for constant velocity ball joints, in which the split die is equally distributed in the circumferential direction on the outer periphery of the coarsely formed material, and the crossed groove is formed by pressing the coarsely shaped material in the axial direction and projecting to the outer periphery. in, it is located on both sides of the circumferential direction of the ridges prior Symbol each divided dies
Radius of the product to be obtained over the entire surface area
By setting the outside in direction, resulting Rubeki product of said outside diameter larger than the outer diameter or have relief portion is formed that allows the coarse profile overhangs Rutotomoni, a circumferential direction of the face
The side edge portion of the inner ring is most distant from the center of the coarsely shaped material .