JPH01192442A - Sizing method - Google Patents

Abstract

PURPOSE:To improve the useful life of a punch and sizing device by ironing an undercut part by facing the punch into the hollow part of a work and executing ironing from the outer periphery of the work by a die with closely fitting the punch to the work. CONSTITUTION:A blank 10 is placed on a punch 36, a 2nd die 34 is displaced a little to a 1st die 32 side and the displacement of the 2nd die 34 is stopped at the position where the tapered part 52 of the bulging part 54 of a die 50 abuts to the blank 10. The punch 36 is further faced into the inner part of the blank 10 to perform the ironing for the inner peripheral face thereof. The sizing is executed so that the ceiling face 16 of the blank 10 may profile to the shape of an outer face part 44. In parallel thereto the notch part of the punch 36 presses the undercut part 24 of both end edges of the bulging part 22 of the blank 10 and it is formed in the necessary dimension. The 2nd die 34 is further displaced to the 1st die 32 side, the die 50 is displaced to the 1st die 32 side, the outer peripheral part of the blank 10 is subjected to ironing by the bulging part 54 and the blank 10 is made a final product.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for sizing layers, such as the outer ring of a constant velocity joint used in an automobile.
When sizing an item that has a hollow cup shape and requires precision in the shape of the inner circumferential groove in which the roller bearing rolls, the required part of the inner circumferential surface of the material is first pressed with a punch. After shaping, the inner circumferential surface of the material is regulated by the punch, and the outer circumferential surface of the material is squeezed by a die to perform final shaping into the inner circumferential groove, thereby finishing the article with precision. Moreover, the present invention relates to a sizing method that makes it possible to minimize galling and wear of punches and the like.

[Background of the Invention] Conventionally, a cold working method for bringing an article processed by forging or casting to its final finished size is called sizing. For example, in the wheel drive unit of an automobile, the above-mentioned sizing method is employed in the manufacturing process of the outer wheel of a constant velocity joint that connects a differential device and a rear wheel shaft.

That is, the outer ring of the constant velocity joint has a couple-like shape, and a plurality of grooves are formed in the axial direction of the inner surface of the outer ring. Since a rotatable bearing between the spider and the spider comes into contact with the groove, the groove needs to be formed with considerable precision. Therefore, the groove must be finished with high dimensional accuracy and surface accuracy by sizing.

Methods for sizing the outer ring of such a constant velocity joint include outer ironing and inner ironing. In this case, outer ironing means that the inner surface of the material is formed in advance to be slightly larger than a predetermined size, and a punch of a predetermined size is inserted into the inner surface, and the outer surface of the material is squeezed with a die to imitate the shape of the punch. (Tokuko Showa 4th)
8-19806). On the other hand, internal ironing is a process in which the inner surface of the material is formed slightly smaller than a predetermined size, and a punch of a predetermined size is inserted into the inner surface to iron the inner surface. Fifth
9-27668).

By the way, roller bearings that roll in the inner circumferential groove of the outer ring constituting the constant velocity joint are classified into two types, spherical rollers and cylindrical rollers, depending on their shapes. In this case, when a spherical roller is used, the spherical roller and the roller rolling surface of the outer ring come into point contact with each other when the rotational force is transmitted by the constant velocity joint. Therefore, the outer ring is required to have considerable strength. Therefore, generally, a cylindrical roller is used in which the roller and the roller rolling surface of the outer ring are in line contact.

When using a cylindrical roller, it is necessary to form a protrusion inside the outer shaft to prevent the cylindrical roller from coming off. In this case, a notch, that is, an undercut, is formed at the base of the protrusion, and both ends of the cylindrical roller are held by the undercut and the opposing inner peripheral surface of the outer ring.

However, among the above-mentioned sizing methods, it has been pointed out that the sizing method using external ironing has the disadvantage that flow due to plastic deformation of the material is difficult to occur in the undercut portion, and therefore it is impossible to obtain the desired shape or dimensional accuracy. ing.

On the other hand, in the case of the Ising method that uses internal ironing, the punch must be pressed in with a considerably large load in order to cause the material to flow out from the undercut part through plastic deformation and form a protrusion of the desired size. The wear of the punch is significant, which reduces the durability of the punch itself, and also causes the problem that the punch is likely to be galled, and in the worst case, it will be destroyed. Furthermore, in this case, when forming the roller rolling surface, which requires the most precision, various distortions appear due to the punches that are press-fitted, making it impossible to obtain a high level of surface precision. The drawback of not being able to maintain a durable life is exposed.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned disadvantages, and the present invention has been made in order to overcome the above-mentioned disadvantages. When sizing an article having a protrusion and an undercut formed at the base of the protrusion into the final shape, first, use a punch to punch the inner surface of the article formed into the substantially final shape. The bearing rolling surface is sized by inserting the material into the material and ironing the necessary parts of the inner surface of the material, and then squeezing the outer periphery while restricting the material with the punch. A sizing method that does not require a very large pressing force when inserting a roller, thereby improving the durability of punches, sizing devices, etc., and particularly improving the machining accuracy of roller rolling surfaces. The purpose is to provide

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention uses a die and a punch for a workpiece having a substantially final shape having a hollow portion and an undercut portion in a portion that bulges into the hollow portion. A sizing method in which ironing is performed to form a workpiece to a predetermined dimensional accuracy by using a sizing method, the method includes defining a predetermined gap between an inner surface defining a hollow part of a workpiece and an outer circumferential surface of the punch, and A first step of selecting a punch having a press-fitting allowance in a specific part of the punch for the undercut portion, and a second step of inserting the punch into the hollow portion of the workpiece and ironing the undercut portion into a predetermined shape. and a third step of ironing the work from the outer periphery using a die while keeping the punch in close contact with the work.

Further, in the present invention, the workpiece has a cup shape, and the inner peripheral surface thereof has a groove portion defined by a rolling surface on which the bearing rolls and a ceiling surface and extending in the axial direction, and a groove portion for preventing the bearing from coming off. The workpiece is characterized in that it has a substantially final shape of a constant velocity joint in which a bulging portion and an undercut portion on the groove side of the bulging portion are formed.

Further, the present invention provides that the first step is to define a predetermined gap between the rolling surface of the inner circumferential surface of the workpiece and the outer circumferential surface of the punch, and to define a predetermined gap at a specific portion of the punch corresponding to the ceiling surface and the undercut portion. The process consists of selecting a punch with a press-fitting allowance of
The second step consists of inserting the punch into the workpiece and ironing the undercut portion and the ceiling surface into a predetermined shape. The method is characterized by comprising the steps of ironing the workpiece from the outer peripheral surface using a die while regulating the upper part and the ceiling surface, and pressing the rolling surface against a punch to finish the workpiece into a final shape.

Further, in the present invention, the first step defines a predetermined gap between the rolling surface and the ceiling surface of the workpiece and the outer peripheral surface of the punch, and corresponds to the ceiling surface edge and the undercut portion. The process consists of selecting a punch having a predetermined press-fitting allowance for a specific part of the punch, and the second process involves inserting the punch into the workpiece and ironing the undercut portion and the edge of the ceiling surface into a predetermined shape. It consists of a process,
In the third step, while the punch is in close contact with the work, the undercut portion and the edge of the ceiling surface are restricted, ironing is performed from the outer circumferential surface of the work using a die, and the ceiling surface and rolling surface are punched. The method is characterized by comprising a step of finishing the work into a final shape by pressing the work into contact with the work.

[Embodiments] Next, preferred embodiments of the sizing method according to the present invention will be described in detail with reference to the accompanying drawings.

First, a blank 10 to be finally processed into an outer ring of a constant velocity joint by implementing the sizing method according to the present invention will be described. This blank 10 has already been formed by casting or forging into the substantially final shape of the outer ring of a constant velocity wheel.

In FIG. 1, the blank 10 has a cup shape with a driven shaft 12 integrally formed on one end thereof and open at the other end. Three rolling grooves 14 extending in the axial direction of the blank 10 and receiving trunnions (not shown) are formed at equal angles apart from each other. In this case, the rolling groove 14 is connected to the ceiling surface 16 and the roller rolling surface 18.2.
0, and a bulge 22 is formed between the three rolling grooves 14 so as to point inward. The roller rolling surfaces 18 and 20 are provided at both end edges of the bulging portion 22.
An undercut portion 24 is formed toward the bottom.

Note that a tapered portion 26 is formed at the edge of the ceiling surface 16 on the roller rolling surface 18.20 side.

Next, a sizing device for carrying out the sizing method according to the present invention will be described.

As shown in FIG. 2, the sizing device 30 includes a first mold 32 and a second mold 34, and the first mold 32 and the second mold 34 are arranged as indicated by arrows in the figure. In addition, they can be relatively displaced in directions toward and away from each other under the driving action of an actuator (not shown). Said first mold 32
A punch 36 is attached to the upper surface of. The punch 36
3 of the blank 10 whose outer shape is molded to correspond to the inner shape of the outer ring of the constant velocity joint.
Three prismatic portions 40 corresponding to the rolling grooves 14 of the strip are formed in a bulging manner, and between these prismatic portions 40, the bulging portion 22 and the undercut portion 24 of the blank 10 are formed with a predetermined precision. A long groove 42 for finishing is formed.

In the punch 36 configured in this way, the prismatic portion 4
0 and the long groove 42 can enter the inside of the blank 10 with a predetermined press-fitting allowance and clearance. That is, as shown in FIG. 3a, in the prismatic portion 40 of the punch 36, a predetermined press-fitting allowance is set on the outer surface 44 with respect to the ceiling surface 16 of the blank 10;
0 side portion 46 and the roller rolling surface 18 of the blank 10
A clearance at a predetermined interval is defined between the two. On the other hand, in the length a42 of the punch 36, the long groove 42
The undercut portion 2 of the blank 10 is inserted into the cutout portion 48 at both ends of the blank 10.
A predetermined press-fitting allowance for the blank 4 is set, and the bulging portion 22 of the blank 10 is configured to have a predetermined clearance with respect to the long groove 42.

In contrast to the first mold 32 configured as described above, the second mold 34 has a substantially cylindrical shape, and a die 50 is attached to the lower end thereof. As shown in FIG. 4, the die 50 has a substantially ring shape, and a bulging portion 54 that goes around the die 50 via a tapered portion 52 is formed at the upper part of the inner peripheral surface thereof. In this case, the inner diameter of the second mold 34 is selected to be larger than the inner diameter of the hollow portion defined by the bulge 54 of the die 50.

The apparatus for implementing the sizing method according to the present invention is basically configured as described above, and next, using this sizing apparatus 30, the actual blank 10 is
is sized and formed into the shape of the final constant velocity joint outer ring.

That is, in FIG. 4a, the blank 10 is
6. Place it on top. In this case, a punch 36 with a press-fitting allowance is used.
The end of the blank 10 comes into contact with the guide 56, and the guide 56 is brought into contact with the side surface of the blank 10 in order to ensure positioning accuracy of the blank 10.

Therefore, the second mold 34 is slightly displaced toward the first mold 32 side, and the second mold The displacement of the mold 34 is stopped. Thereby, the blank 10 is positioned and held by the guide 56 and the die 50.

Next, as shown in FIG. 4, the second mold 34 is further displaced to the punch 36 side, so that the punch 36
0 and ironing the inner peripheral surface thereof. In this case, as shown by the arrow in Figure 3a,
The outer surface 44 of the prismatic portion 40 of the punch 36 is the blank 1.
A part of the inner circumferential surface of 0, that is, the ceiling surface 16 is pressed. Therefore, the ceiling surface 16 of the blank 10 pressed against the outer surface portion 44 is sized to follow the shape of the outer surface portion 44 . Further, in parallel with this, the cutout portion 48 of the punch 36 presses the undercut portions 24 at both ends of the bulge portion 22 of the blank 10, and the undercut portions 24 are substantially adjusted to desired dimensions. It comes to be molded. In this way, when the ironing of a part of the inner circumferential surface of the blank 10 is completed, the blank 10 has been formed into the shape shown in FIG. 3.

Subsequently, the second mold 34 is further displaced toward the first mold 32 side, the die 50 is displaced toward the first mold 32 side, and the bulging portion 54 of the die 50 causes the outer periphery of the blank IO to Ironing is performed (see Figure 4C). In this case, as can be easily understood by referring to Figure 3, in the clearance previously defined between the blank 10 and the punch 36, the roller of the blank lO is moved as shown by the arrow in the figure. The rolling surface 18, 20 and the bulge 22 are the punch 3.
Plastic deformation that closely adheres to 6 occurs. As a result, the blank 10 is sized to follow the shape of the punch 36 as shown in FIG. 3C, and the outer ring of the constant velocity joint is obtained as a final product.

In addition, when carrying out the above sizing process, the vertical relationship of the first mold 32 and the second mold 34 is reversed, and the first mold 3
2 may be displaced downward toward the second mold 34 side. In this case, since the blank 10 is positioned by the die 50,
The id 56 in FIG. 3a becomes unnecessary.

In this case, according to this embodiment, it is possible to form the roller rolling surfaces 18, 20 and the undercut portion 24 on the inner peripheral surface of the blank 10 with extremely high precision. That is, when ironing the inner circumferential surface of the blank 10 with the punch 36, the prismatic portion 40 of the punch 36
By providing a press-fitting allowance in the outer surface portion 44 and notch portion 48 of the blank 10, first, a portion of the inner circumferential surface of the blank 10, that is, the ceiling surface 16 and the undercut portion 24, is ironed. The ceiling surface 16 and a portion other than the undercut portion 24, that is, the roller rolling surface 18.
A clearance is defined between the punch 36 and the bulge 20 . Therefore, it is possible to secure a space for releasing the strain generated during the ironing process, and to suitably promote the flow of the material due to plastic deformation. Also,
In this way, since the entire inner circumferential surface of the blank 10 is not ironed all at once, no unreasonable force is applied to the punch 36, and the punch 36 bites into the inside of the blank 10 and becomes unable to come out. This accident can be avoided. Furthermore, in this case, the punch 36
In the prismatic portion 40, force acts in a well-balanced manner on the outer surface portion 44 and the notch portion 48, and therefore, it is possible to improve the durability of the punch 36 without causing damage.

On the other hand, following the inner periphery ironing of the blank 10 using the punch 36, the blank 10 is
The blank 1 is cut by the die 50 while maintaining the regulation of the ceiling surface 16 and the undercut portion 24 on the inner peripheral surface of the blank 1.
Ironing is performed on the outer peripheral surface of 0. As a result, the roller rolling surface 18.20 of the blank 10 is punched by the punch 36.
When the ceiling surface 1 is pressed against the side surface 46 and deformed, the ceiling surface 1
6 and the undercut portion 24, and the machining accuracy of the roller rolling surface 18, 20 as well as the ceiling surface 16 and the undercut portion 24, which are already dimensioned, is improved.

Next, another embodiment of the sizing method according to the present invention is shown in FIG. In this case, as can be easily understood from FIG. The difference is that there is a press-fit allowance on the edge. Therefore, when inserting the punch 36 into the blank 10 and ironing the inner circumference, the blank 10
The tapered portion 26 at the edge of the ceiling surface 16 is squeezed. Then, the outer periphery is ironed using the die 50, and the ceiling surface 16 of the blank 10 is pressed using the punch 36.
(See FIG. 5C). Note that the molding of other parts of the blank 10 is the same as in the first embodiment.

As in this second embodiment, portions of the blank 10 may be selectively ironed during the initial inner periphery ironing. Also in this case, the balance of the forces acting on the punch 36 is taken into consideration when determining the dimensions of the undercut portion 24 of the blank 10.

[Effects of the Invention] As described above, according to the present invention, when the punch and die work together to finish the outer ring of a constant velocity joint into the final product shape, first the punch is used to remove the material of the outer ring. By inserting the blank into the blank and ironing the inner circumferential surface of the blank to obtain the dimensions of a specific part of the inner circumferential surface, that is, the undercut part, and then squeezing the outer circumference of the blank with a die, The inner peripheral surface of the blank is brought into close contact with a punch to form the final product shape. Therefore, there is an advantage that no unreasonable force is applied to the punch, and its durability is improved.

In addition, when ironing the outer periphery, the area where the dimensions have been obtained by ironing the inner periphery with a punch is regulated by the punch, so there is no interference between other areas due to the flow of the material, and therefore, especially when conventional dimensional accuracy is The effect is that it is possible to accurately size the undercut portion and the roller rolling surface, which have been difficult to remove.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

Figures 1a and b are partially omitted longitudinal and cross-sectional views showing the structure of a blank processed into the outer ring of a constant velocity joint by the sizing method according to the present invention, and Figure 2 is a longitudinal sectional view and a cross-sectional view showing the configuration of a blank processed into the outer ring of a constant velocity joint by the sizing method according to the present invention. A partially omitted perspective explanatory view of a sizing device for carrying out the sizing process; Figures 3a to C are explanatory diagrams of the sizing action of the punch and die in the sizing method according to the present invention; Figures 4a to C are shown in Figure 2; A diagram explaining the order of the sizing method according to the present invention carried out using a sizing device. FIGS. 5A to 5C are operation explanatory diagrams according to other embodiments of the sizing method according to the present invention. 10... Blank 12... Driven shaft 1
4...Rolling groove 16...Ceiling surface 18
．． 20...Roller rolling surface 22...Bulging portion 30
...Sizing device 32.34...Mold 3
6... Punch 40... Square column part 42
...Long groove 50...Die 52...
・Tapered part 54...Bulging part FIG, 1

Claims (4)

[Claims] (1) Sizing, in which a workpiece with a substantially final shape that has a hollow part and an undercut part in the part that bulges into the hollow part is ironed using a die and a punch to form it to a predetermined dimensional accuracy. The method includes selecting a punch that defines a predetermined gap between an inner surface defining a hollow portion of the workpiece and an outer circumferential surface of the punch and has a press-fitting allowance at a specific portion of the punch relative to the undercut portion. a first step, a second step of inserting the punch into the hollow part of the workpiece and ironing the undercut into a predetermined shape; A sizing method characterized by comprising a third step of ironing and forming. (2) In the method according to claim 1, the workpiece has a cup shape, and the inner peripheral surface thereof has a groove portion extending in the axial direction and defined by a rolling surface on which the bearing rolls and a ceiling surface, and a groove portion extending in the axial direction. A sizing method comprising: a workpiece having substantially the final shape of a constant velocity joint in which a bulge for preventing the bulge from coming off and an undercut portion on the groove side of the bulge are formed. (3) In the method according to claim 2, the first step is to define a predetermined gap between the rolling surface of the workpiece and the outer circumferential surface of the punch on the inner circumferential surface of the workpiece, and to correspond to the ceiling surface and the undercut portion. It consists of a step of selecting a punch having a predetermined press-fitting allowance for a specific part of the punch, and a second step is a step of inserting the punch into the workpiece and ironing the undercut portion and the ceiling surface into a predetermined shape. The third step is to iron the workpiece from the outer peripheral surface with a die while keeping the punch in close contact with the workpiece and restricting the undercut portion and ceiling surface, and press the rolling surface to the punch. A sizing method comprising the step of finishing the workpiece into a final shape. (4) In the method according to claim 2, in the first step, a predetermined gap is defined between the rolling surface and the ceiling surface of the inner peripheral surface of the workpiece and the outer peripheral surface of the punch, and the green part of the ceiling surface and The second step consists of selecting a punch having a predetermined press-fitting allowance for a specific part of the punch corresponding to the undercut, and the second step is to insert the punch into the workpiece to form the undercut and the edge of the ceiling surface into a predetermined shape. The third step is ironing forming from the outer peripheral surface of the workpiece using a die while keeping the punch in close contact with the workpiece and regulating the undercut portion and the edge of the ceiling surface. A sizing method comprising the steps of pressing the ceiling surface and the rolling surface with a punch to finish the workpiece into a final shape.