JPH0639478A - Producing mechanism for lovrd joint @(3754/24)cross groove universal joint) outer ring - Google Patents

Abstract

PURPOSE:To prevent the crack and the breakage of a die and to promote a fill-up around a cross groove. CONSTITUTION:In base plates 60a diagonally forming projection lines 60b for forming the cross grooves, the projection parts 61 are arranged on the diagonal line in the direction crossed to this projecting lines 60b, or in the neighborhood thereof. Both side surfaces 60c, 60d of the base plate part 60a are formed as the tapered surface. Bending moment toward the outer part in the radius direction to the base plate part 60a developed through this tapered surfaces at the time of forming is cancelled by bringing the projecting parts 61 into contact with the inner surface of a preformed material 4 and receiving the load from the outer part. Therefore, as excess bending is not acted to the base plate part 60a, the crack and the breakage of the divided die 60 are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for manufacturing an outer ring of a rebro joint which is a kind of constant velocity joint.

[0002]

2. Description of the Related Art First, an example of the shape of the outer ring of a rebro joint to which the present invention is applied will be described.
A hollow cup portion is provided at one end of the shaft portion, and a plurality of cross grooves are formed on the inner surface of the cup portion. The cross grooves are formed in the spiral direction with respect to the inner surface of the cup portion, and the directions of the adjacent cross grooves are opposite to each other. An example of this type of outer ring is shown in FIGS. 8 and 9, in which reference numeral 1 indicates a shaft portion, reference numeral 2 indicates a cup portion, and reference numeral 3 indicates a cross groove.

As a method of forming the cup portion 2 of the rebro joint outer ring, a forging method has been conventionally adopted in order to improve productivity and material yield. An example of the method will be described with reference to FIG. , As follows:

That is, in FIG. 10, the applicant of the present invention filed Japanese Patent Application No. 3-
FIG. 2 is a cross-sectional view schematically showing the device proposed in No. 283854, in which a mandrel punch 5 is inserted inside a rough material 4, and the mandrel punch 5 is provided with the cross groove 3;
A plurality of split dies 6 provided with ridges for forming
The holder 7 is held on the outer peripheral portion at a constant interval.
A plurality of radial dies 8 that move back and forth in the radial direction of the rough material 4 are arranged on the outer peripheral side of the rough material 4, and a wedge member 10 is provided between the radial dies 8 and the reaction force receiving portion 9. Has been inserted. Therefore, by pushing the wedge member 10 between the radial die 8 and the reaction force receiving portion 9, the radial die 8 presses the rough material 4 toward the split die 6,
As a result, the rough material 4 is plastically deformed along the mandrel punch 5, and the outer ring of the rebro joint having the desired shape is obtained.

A large load acts on the split die 6, and its positioning accuracy and dimensional accuracy greatly influence the accuracy of the cross groove 3. Therefore, in the past,
As shown in FIG. 11, the split die 6 has a ridge 6b formed on a surface of a substrate 6a having a rectangular cross section along a direction substantially parallel to a diagonal line of the substrate 6a.
The positioning accuracy is improved by using d as a tapered surface. Note that reference numeral 6e is an enlarged portion for forming a grinding clearance.

[0006]

Since the spiral grooves (inclination directions) of the cross grooves 3 of the above-mentioned REBRO joint outer ring are alternately opposite to each other, the intervals between the cross grooves 3,
That is, the interval between the protrusions 6b is alternately changed between large and small in the opening and the bottom of the cup portion 2. Therefore, as shown in FIG.
Locations where b is narrow (hereinafter referred to as a small pitch portion) 1
The material 1 flows into and fills (fills up) 1 before a portion (hereinafter, temporarily referred to as a large pitch portion) 12 having a wide interval between the protrusions 6b. Since the pressure applied to the rough material 4 is continued thereafter, the pressure in the small pitch portion 11 becomes higher than the pressure in the large pitch portion 12. Therefore, an external force that pushes toward the large pitch portion 12 acts on each split die 6 via the ridge 6b, and the direction of the external force is opposite between the opening end side and the bottom side of the cup portion 2, After all, a force acts on the split die 6 in the direction of twisting it. The pressure difference between both sides of the protrusion 6b is further increased if the enlarged portion 6e is formed.

On the other hand, the reaction force against this external force is
It acts from the holder 7 via the side surfaces 6c and 6d of a. In that case, the side surfaces 6c and 6d of the substrate portion 6a are
As described above, since it is tapered for positioning, a component force (indicated by arrow Y in FIG. 12) outward in the radial direction based on the reaction force is generated. As a result, in the molding process, a torque that pushes the base portion 6a of the split die 6 toward the large pitch portion 12 side in the radial direction acts on the portion extending toward the large pitch portion 12, and this causes the ridge 6b. There is a problem that a crack is formed at the boundary between the substrate portion 6a and the substrate portion 6a or the split die 6 is damaged.

As described above, since the filling (fill-up) of the material into the large pitch portion 12 is delayed, the forming load is further increased even after the filling up to the small pitch portion 11 is almost completed and the molding resistance is increased. Therefore, there is a disadvantage that a press machine having a large capacity has to be used. Furthermore, since the fill up of the ridge line portion of the cross groove on the side of the large pitch portion 12 is insufficient, an extra cutting allowance for adjusting the shape is increased, and as a result, there are problems such as an increase in man-hours and a deterioration in material yield. there were.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manufacturing mechanism of a rebro joint outer ring having a good cross groove formability.

[0010]

In order to achieve the above-mentioned object, the present invention forms a cross groove in the inner side of a cylindrical hollow portion in a spiral direction with respect to the inner peripheral surface of the hollow portion. A plurality of divided dies provided with protruding ridges are evenly arranged at regular intervals so that the spiral directions of the ridges are alternately opposite, and the hollow portion toward the divided dies is pressed from the outer peripheral side to achieve plasticity. In a manufacturing mechanism of a Reblo joint outer ring that causes deformation, the split die is provided with one of the protrusions on a rectangular cross-section substrate part having tapered surfaces on both sides receiving a load pressing the hollow part from the outer peripheral side. The structure is formed diagonally in a diagonal direction, and on the surface of the substrate portion on which the ridge is provided, a predetermined location near another diagonal in a direction intersecting with the ridge or the hollow facing the predetermined location. The inner surface of the part has few predetermined places Also characterized in that the protrusions are formed in one.

[0011]

The split die according to the present invention is arranged inside the rough shaped material so that the spiral directions of the cross grooves to be formed by the protrusions are alternately opposite to each other, and the outer circumferential side of the rough shaped material is directed toward the split die. A load is applied to the rough shape material to cause plastic deformation. The split die has a rectangular cross-section substrate portion formed with protrusions diagonally along the diagonal direction thereof, so that a portion that greatly extends toward the so-called large pitch portion is located on each end side of the protrusions. Has been formed. Further, this split die is held by the tapered surfaces on both sides thereof. Therefore, due to the difference in material fill-up on both sides of the ridge, a load is applied to the split die in the lateral direction, that is, in the circumferential direction of the hollow part of the rough material, and the reaction force against this is tapered. It acts on the side surface, which is a surface, and as a result, a bending moment is applied to the portion of the substrate portion of the split die that extends toward the large pitch portion side. However, since a protrusion is formed at a predetermined position on the inner surface of the hollow portion facing this portion or the portion extending toward the large pitch portion, by contacting the substrate portion and the rough shape member through this protrusion portion, The forming load acts in a direction to cancel the bending moment. Therefore, according to the present invention, it is possible to prevent the split die from cracking or breaking.

Further, when the protrusion is formed on the substrate portion of the split die, the protrusion accelerates the flow of material to the periphery of the protrusion on the so-called large pitch side. Good material fill up around the ridges.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. In the following description of the embodiments, the same parts as those of the conventional example shown in FIGS. 8 to 12 are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a view showing a molding process according to an embodiment of the present invention, in which a Rebro joint outer ring which is an object of the present invention has a shape shown in FIGS. 8 and 9. The split die 60 used here basically has a structure similar to that of the conventional one, and as shown in FIG. 2, a substrate section 60a having a rectangular cross section with both side surfaces 60c and 60d as tapered surfaces, A ridge 60b is formed diagonally in one of the diagonal directions. Further, in the substrate portion 60a, the protrusion portion 61 is formed on the opposing line in the direction intersecting with the protrusion 60b, particularly near both ends thereof. The reference numeral 60e is an enlarged portion for forming a clearance for the grinding process in the cross groove.

Also in this embodiment, each split die 60 is used.
Are held on the outer peripheral portion of the holder 7 at regular intervals while being positioned on both side surfaces thereof, and are arranged on the inner peripheral side of the cup portion 2 in this state. In this arrangement, the protrusions 60b of the adjacent split dies 60 are opposite to each other in the spiral direction of the cup portion 2. Then, the radial die 8 is pressed from the outer peripheral side of the rough material 4 to cause the cup portion 2 to be plastically deformed and to be molded. In that case, the fill-up in the small pitch portion 11 where the interval between the protrusions 60b is narrow precedes, and the fill-up in the large pitch portion 12 where the interval between the protrusions 60b is wide is delayed. As a result, the load on the large pitch portion 12 side acts on the split die 60 due to the difference in pressure on both sides of the protrusion 60b.
Since the reaction force against this load acts via the side surface which is the tapered surface, the portion of the substrate portion 60a extending toward the large pitch portion 12 acts outward in the radial direction via the tapered surface. The component force that acts acts as a bending moment.

On the other hand, since the protrusion 61 is formed on the portion of the substrate portion 60a extending toward the large pitch portion 12, the protrusion is formed at the same time when the molding is started or when the molding is advanced to some extent. The portion 61 contacts the inner surface of the rough shape member 4. Since the rough material 4 is pressed toward the center by the radial die 8, the protrusion 61 comes into contact with the inner surface of the rough material 4 to extend toward the large pitch portion 12 side of the substrate portion 60a. The protruding part is pushed toward the center part, so that the bending moment is canceled out. Since this state continues until the molding of the cup portion 2 is completed, an excessive bending moment that has been conventionally generated does not act on the substrate portion 60a, so that cracking or damage is prevented.

The bending moment described above is caused by the protrusion 6
0b is caused by the difference in the fill-up on both sides. Therefore, if the protrusion 60b is formed with the enlarged portion 60e, the difference in the fill-up and the bending moment become remarkable. It may be provided only on the same end side as the enlarged portion 60e.

Further, as is apparent from the above description, the protrusion 61 has the end portion of the substrate portion 60a before the difference between the fill-ups on both sides of the protrusion 60b and the pressure difference resulting therefrom become excessive. And the inner surface of the cup portion 2 are brought into contact with each other. Therefore, as shown in FIG. 3, for example, as shown in FIG. 3, the protrusion 61 is provided on the inner peripheral surface of the cup portion 2 in addition to the substrate portion 60a of the split die 60.
You may form in the part facing.

The shape of the protrusion 61 is the substrate portion 60a.
Alternatively, it may be provided in any shape such as a polygon, a circle, a triangle, or a sphere even if it is provided on any of the inner surfaces of the cup portion. If a specific example is shown, as shown in FIG.
Square with a side L of 2 to 8 mm and a protrusion height H of 0.1 to 3
A thin plate having a diameter of 2 to 8 mm and a protruding height H of 0.3 to 3 mm can be used as a thin plate having a diameter of 2 mm as shown in FIG.

Next, another embodiment of the present invention will be described.
FIG. 5 shows a split die 6 used in another embodiment of the present invention.
In the split die 60 shown here, a larger protrusion 62 is formed instead of the protrusion 61 shown in FIG. That is, a protrusion 62 having a trapezoidal cross section is formed at a portion of the substrate portion 60a extending to the large pitch portion 12 side so as to be parallel to the protrusion 60b with a constant interval between the protrusion 62 and the protrusion 60b. .

FIG. 6 is a view showing a split die 60 used in still another embodiment of the present invention, in which the split die 60 shown in FIG. The surface is changed from a flat slope to an arc surface.

FIG. 7 schematically shows a molding state using the split die 60 shown in FIG. 5 or the split die 60 shown in FIG. In such a split die 60 as well, since the protrusions 62 come into contact with the inner surface of the rough shaped member 4 from the beginning of molding or at a relatively early time after the start of molding,
A bending moment is not generated in the portion of the substrate portion 60a extending to the large pitch portion 12 side, so that the split die 60 can be prevented from cracking or breaking as in the above-described embodiment.

The split die 60 shown in FIG. 5 and the split die 60 shown in FIG.
However, since a part of the material flow is guided between the ridge 60b and the ridge 60b, as shown by the arrow Z in FIG.
Fill up to the 2nd side is promoted. As a result, the ridge line portion A of the cross groove 3 is formed in a desired shape. Since such a material flow on the large pitch portion 12 side occurs relatively early after the start of molding, that is, in parallel with the material fill-up on the small pitch portion 11 side, a large molding load is not required. It is possible to cause fill-up on the large pitch portion 12 side.

The shape of the protrusion that causes the material to flow toward the large pitch portion 12 may be various other than the shape shown in FIG. 5 or 6.

[0025]

As described above, according to the present invention,
The bending moment for the split dies due to the material fill-up on both sides sandwiching the ridge for cross groove forming,
Since the projection formed on one of the split die or the rough shape member is brought into contact with the other so as to be offset by the molding load, cracks and breakage of the split die are prevented in advance to improve the mold life, As a result, the cost of parts can be reduced. Further, since the substrate portion of the split die can be thinned, the die cost can be reduced, and further, since the split die is not deformed at the time of molding, the accuracy of the inclination angle and pitch of the cross groove can be improved.

If the protrusion is formed on the substrate of the split die, the flow of the material can be guided toward the periphery of the ridge, so that the fill-up property to the periphery of the ridge is improved and the cross groove is formed. It is possible to clarify the shape of the ridge and, by extension, omit or reduce post-processing, and accordingly improve the material yield. Further, since the molding load may be small, the capacity of the press machine can be reduced.

[Brief description of drawings]

FIG. 1 is a partial view showing a molding process according to an embodiment of the present invention.

FIG. 2 is a perspective view showing one of the split dies.

FIG. 3 is a cross-sectional view showing an example of the rough material.

FIG. 4 is a perspective view showing an example of the shape of a protrusion.

FIG. 5 is a perspective view showing another example of the split die.

FIG. 6 is a perspective view showing still another example of the split die.

FIG. 7 is a partial view showing a state where molding is performed using the split die shown in FIG.

FIG. 8 is a plan view of a rebro joint outer ring.

FIG. 9 is a cross-sectional view of a rebro joint outer ring.

FIG. 10 is a partial cross-sectional view showing an example of a manufacturing apparatus already proposed by the applicant.

FIG. 11 is a perspective view showing an example of a conventional split die.

12 is a partial view showing a state where molding is performed using the split die shown in FIG. 11. FIG.

[Explanation of symbols]

 2 cup part 3 cross groove 4 rough material 60 split die 60a substrate part 60b ridges 60c, 60d side face 61, 62 protrusion part

Claims (1)

[Claims] 1. A plurality of split dies, each of which is provided with a projecting ridge for forming a cross groove in a spiral direction with respect to an inner peripheral surface of the hollow inside of the cylindrical hollow part, In the manufacturing mechanism of the Rebro joint outer ring for uniformly deforming the spiral direction alternately at regular intervals, and causing plastic deformation by pressing the hollow portion toward the split die from the outer peripheral side, the split die is It is a structure in which the protrusions are formed obliquely in one diagonal direction on a substrate portion having a rectangular cross section with tapered surfaces on both sides receiving a load that presses the hollow portion from the outer peripheral side, and the protrusion of the substrate portion is formed. A protrusion is formed on at least one of a predetermined location in the vicinity of another diagonal line in the direction intersecting with the protrusion or a predetermined location on the inner surface of the hollow portion facing the predetermined location on the surface provided with the stripe. Is characterized by Production mechanism of Les Bro joint outer ring.