JPH11722A - Press formed parts, forming method thereof and forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a shape without hindrance to use the inside surface on the side of a cylindrical part with a groove by forming the groove with a press on the side of a plate-shaped part in the vicinity of the corner part on the outside of a bended part where the cylindrical part and plate-shaped part are mutually connected. SOLUTION: A groove forming punch 7 is lowered. Before the back surface of the plate-shaped part 14 is brought into contact with a die 8, bite into the work W with a projected line 71 is started and, as a result, thickness on the inner side of the projected line in the radial direction of the material flows plastically toward the corner part. Compression with the groove forming punch 7 is further progressed, the back surface of the plate-shaped part 14 is brought into contact with the die 8 and, when compression acts slightly on the entire surface of plate, forming stroke is ended. In this stage, the radius R' of the corner is also formed to the chamfering in upper corner part on the inner peripheral side of the die 8. In such a case, the plastic flow of thickness of the material in the direction of the corner part is already enough executed, so it is not neccessay to especially inrease a compressive load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-formed part, a method for forming the same, and a forming apparatus, and more particularly to press-forming a corner of a drum-shaped part.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a drum-shaped part, a processing method of drawing a plate-shaped material into a cylindrical shape by drawing is employed. For example, as shown in FIG. 5, such a drum-shaped component is used as a stepped drum D of a multi-plate clutch or a multi-plate brake as a friction engagement device such as an automatic transmission. In this example, the small-diameter cylindrical portion Ds of the stepped drum D is
The hydraulic servo piston P is a cylinder on which the piston slides, and the large-diameter cylindrical portion Dl is a support for the friction engagement element F.

[0003] By the way, at the corner of the bent portion L connecting the cylindrical portion Ds and the plate-shaped portion Df of such a drum-shaped component,
According to the press working, a certain degree of roundness is formed (in the sense of indicating a radius when viewed in a cross section, it is generally called a radius (R), and accordingly, the roundness of a corner portion is referred to as a corner radius throughout this specification). Inevitable. It is difficult for the corner radius to be equal to or less than the sheet thickness by ordinary press molding.

[0004]

[0006] Such a corner radius may not be preferable depending on the use form of the component. In particular, as in the above example, when the corner radius is one end of the cylinder and the seal portion of the piston P is in contact with the corner radius, leakage of servo hydraulic pressure occurs. Therefore, in such a case, the corner radius is outside the sliding range of the seal portion, and an extra shaft length is required for the drum D, which hinders the compactness of the apparatus. Conversely, if the corner radius can be reduced, the stroke amount of the piston P can be effectively secured within a limited space.

[0005] In view of this, the side to become the plate-shaped portion Df at the time of press-forming the work W as shown in FIG. Further, the outer corner R of the boundary between the cylindrical portion Dl and the plate-shaped portion Df is reduced by being compressed between the flat portion punch a and the die b. However, in the compression by the flat pressing punch a, there is a limit in obtaining a corner radius R approximately equal to the thickness of the work W. Further, even if the compression force of the punch a is increased in order to further reduce the corner radius, the material spreads to the side opposite to the corner portion, and the corner radius cannot be sufficiently reduced. So, in order to prevent the flesh of such material from escaping in the outer diameter direction,
As shown in FIG. 7, it is not inconceivable to consider a method of restricting the outer peripheral side by the die c. However, in such a case, the load between the plate-shaped portion Df of the work W and the die c increases.
There is a concern that the die c may be cracked or deformed at the time of dispensing due to the work W sticking to the die c.

Accordingly, the present invention provides a press-formed product comprising:
It is a first object to provide a shape capable of obtaining a small corner radius.

A second object of the present invention is to obtain an effective groove position for obtaining the small corner radius.

A third object of the present invention is to obtain the small corner radius over the entire circumference of the press-formed product.

A fourth object of the present invention is to reduce the size of the automatic transmission by utilizing a press-formed product having the small corner radius.

Next, a fifth object of the present invention is to provide a method for forming the above-mentioned molded part.

A sixth object of the present invention is to provide an apparatus used for carrying out the above-mentioned molding method.

Further, the present invention provides the above molding apparatus,
A seventh object is to provide a punch shape that promotes formation of a small corner radius while improving the durability of the punch and the mold release performance.

[0013]

In order to achieve the first object, the present invention relates to a press-formed part having a cylindrical portion and a plate-shaped portion, wherein the bent portion connects the cylindrical portion and the plate-shaped portion to each other. A groove formed by pressing is formed on the plate-like portion near the outer corner portion of the portion.

Next, in order to achieve the second object, a configuration is adopted in which the groove is located on an extension of the outer peripheral surface of the cylindrical portion.

Further, in order to achieve a third object, the groove is formed so as to surround a corner portion.

In order to achieve the fourth object, the press-formed part is a drum-shaped member used for a friction engagement device of an automatic transmission.

According to a fifth aspect of the present invention, there is provided a method for forming a press-formed part by a punch and a die, wherein the inner part of the cylindrical part of the formed part is connected to the cylindrical part while being supported by the punch. At the time of pressing the plate-shaped part by pressing the die against the die with a punch, a groove is formed by pressing the punch on the plate-shaped part near the outer corner of the bent part where the cylindrical part and the plate-shaped part are connected to each other. Configuration.

According to a sixth aspect of the present invention, there is provided an apparatus for forming a press-formed part using a punch and a die, wherein the cylindrical part and the plate-shaped part of the formed part are mutually opposed on a surface of the punch facing the die. On the side of the plate-shaped portion near the outer corner portion of the connected bent portion, a ridge for forming a groove is provided.

Further, in order to achieve the seventh object, the ridge is configured to have a trapezoidal cross section with the upper side facing the die.

[0020]

According to the first aspect of the present invention, the groove for reducing the corner radius of the press-formed part by plastically flowing the flesh of the material toward the inner diameter side of the plate-shaped part is formed. Since the groove is formed on the plate surface side, it is possible to realize a form in which the groove does not hinder the use of the inner surface of the cylindrical portion while obtaining a small corner radius by forming the groove.

According to the second aspect of the present invention, the material is effectively plastically flowed into the corner portion on the inner diameter side of the plate-shaped portion to reduce the corner radius without deteriorating the component strength. A part form is obtained.

Further, according to the configuration of the third aspect, the corner radius of the press-formed part can be reduced over the entire circumference.

Further, according to the configuration of the fourth aspect, since the corner radius is small, the piston stroke of the clutch or the brake, which is the friction engagement device of the automatic transmission, can be lengthened in a limited space. . As a result, the axial dimension of the automatic transmission can be reduced.

According to the fifth aspect of the present invention, since the groove is formed near the corner where the cylindrical portion and the plate-shaped portion of the press-formed part are connected, the material of the material is reduced at the time of forming the groove. The plastic flow can be caused to flow toward the inner diameter side of the groove toward the groove, and a press-formed part having a small corner radius can be obtained.

Next, according to the forming apparatus of the present invention, the groove is formed on the punch so that the ridge is formed near the corner where the cylindrical part and the plate part of the press-formed part are connected. When forming the groove, not only can the material of the material be prevented from flowing to the outer diameter side of the plate-shaped part, but also the plastic flow can be positively plastically flowed to the inner diameter side corner, and the groove forming ridge is formed on the punch. Only by providing the same, the corner radius of the press-formed part can be reduced.

Further, according to the configuration of the seventh aspect, the inclination of the trapezoidal side surface of the ridge on the side of the corner promotes the extruding of the meat of the material in the direction of the corner, thereby improving the flow of the meat. The corner radius can be further reduced.
In addition, the inclination of both sides of the trapezoidal side surface of the ridge makes it easy to remove the punch, thereby facilitating dispensing of the formed part after processing. Furthermore, since the upper base of the trapezoid of the ridge is flat, the durability of the ridge of the punch is improved.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an axial cross section of a press-formed part according to the embodiment. This part is composed of three cylindrical tubular parts 11, 12, 13 and three disk-shaped plate parts 14, 15. , 16 and a stepped drum-shaped member 1 having a conical portion 17 and having a uniform cross section in the circumferential direction.

According to the present invention, the cylindrical portion 1 of the drum-shaped member 1
A groove 18 is formed by pressing on the plate-like portion 14 near the outer corner R of the bent portion L where the plate 1 and the plate-like portion 14 are connected to each other. The groove 18 is formed around the corner portion R so as to be located on an extension of the outer peripheral surface S of the tubular portion 11.

As shown in FIG. 2, the drum-shaped member 1 as a press-formed part according to this embodiment is used as a hydraulic servo cylinder in a friction engagement device of an automatic transmission, for example. In this use mode, the plate-like portion 14 of the drum-like member 1 is formed with spline peaks between the grooves by a subsequent groove cutting process, and is fitted into the inner peripheral spline groove 21 of the transmission case 2 so as not to rotate. Is axially stopped by the drum-shaped member 3. On the inner periphery of the drum-shaped member 1,
A piston 4 having a similar shape is axially movably fitted, and O-rings 41 and 42 arranged near both ends in the axial direction of the piston 4 allow the inner periphery of the cylindrical portion of the drum-shaped member 1 and the piston 4 to have the same shape. Leakage between the outer periphery of the cylindrical portion is prevented.

As is well known, the piston 4 supplies a hydraulic pressure between the piston 4 and the cylinder made of the drum-shaped member 1 to move the piston 4 from the initial retracted position (the position shown) due to the load of the return spring 5 to the return spring. 5 is compressed and pushed out in the axial direction (to the right in the example of the figure), and the frictional engagement device is brought into engagement by pressing the brake plate 6 with the tip of the piston 4. With the movement of the piston 4, the O-ring 41 fitted to the distal end side of the piston 4 also moves the cylindrical portion 1 of the drum-shaped member 1.
1 slides to the tip side. The limit of the engagement direction of the piston stroke is just before the O-ring 41 reaches the corner radius of the drum-shaped member 1. This is because when the O-ring 41 reaches the corner radius, oil leakage may occur.

Thus, according to the friction engagement device of this embodiment, the corner radius is substantially reduced to about half of the plate thickness, so that the same piston is used as compared with the conventional case where the corner radius is greater than the plate thickness. In order to obtain a stroke, the axial dimension of the cylinder composed of the drum-shaped member 1 can be shortened accordingly. This contributes to a reduction in weight and size by reducing the axial dimension of the entire automatic transmission. Moreover, since the groove 18 for reducing the corner radius R over the entire circumference is located on the plate surface side of the corner portion, the groove 18 makes the inner surface of the cylindrical portion side the piston sliding surface without impairing the component strength. A form that does not hinder use can be realized.

Next, FIG. 3 shows an apparatus for forming the press-formed part. In the figure, the left half shows the state before molding, and the right half shows the state after molding. This device is a device for forming a press-formed part W by a groove forming punch 7 and a die 8, and a lower holder 90 for holding the die 8.
The pad 92 is supported by a pad spring 91 so as to hold the work W and be lowered for forming and lifted for discharging, and a lifter 93 which is arranged to surround the outer periphery thereof and which can be raised and lowered similarly. And a die 8 which is arranged so as to surround the outer periphery thereof and is fixed by pressing the outer peripheral side with a pressing plate 94.

On the other hand, a punch 101 fitted on the inner peripheral side of the work W is fixed to the upper plate 100 via a backing plate 102, and the groove forming punch 7 is guided by the knockout pin 103 so as to surround the outer periphery. The knockout 104 supports the punch 101 so as to be able to move up and down. The groove forming punch 7 is provided with groove forming ridges 71. The ridge 71 has a trapezoidal cross section with the side facing the die 8 as the upper bottom. In the drawings, reference numeral 95 indicates a guide bush, 96 indicates a lifter pin, 97 indicates a cushion pin, 98 indicates a spool retainer, 105 indicates a guide post, 106 indicates an upper holder, and 107 indicates an adapter plate.

Finally, the molding method will be described with reference to FIGS. As shown in FIG. 3, in this embodiment, in the material W, another portion has already been formed by drawing, and only the plate-shaped portion 14 remains at a large corner radius. The workpiece W in this state is placed on the pad 92 with the processing portion facing upward.
Align with the top.

When the elevator is lowered, the groove forming punch 7 is lowered as shown in FIG.
01 also descends and fits on the circumference of the work W. FIG. 4A shows a state before the molding, and the work W is supported by the punch 101, the die 8 and the lifter 93 to support the cylindrical portion 11 and the plate-like portion 15 and is immovably restrained.

Next, the molding is started, and the groove forming punch 7 is lowered as shown in FIG. As a result, before the lower surface of the plate-shaped portion 14 has not yet contacted the die 8, the ridge 71 starts to bite into the work W, and accordingly, the material radially inward of the ridge 71 of the material faces the corner portion ( Plastic flow in the direction of the arrow). In this case, the radial position of the ridge 71 is such that the material can be effectively extruded radially inward from the ridge 71, and the position of the workpiece W is as close to the corner as possible in processing. It is on an extension of the outer peripheral surface of the shape portion 11.

Further, the compression by the groove forming punch 7 further proceeds, and as shown in FIG. 4C, the lower surface of the plate-like portion 14 comes into contact with the die 8 and a slight compression acts on the entire plate surface. , End the molding stroke. Thus, a corner radius of about half the thickness of the work can be formed at the bent portion of the work W. In this process, the corner radius R ′ of the inner corner side of the bent portion is also formed in accordance with the chamfer of the inner peripheral upper corner of the die 8. In this case, since the plastic flow of the material in the direction of the corner has already been sufficiently performed according to the present invention, it is not necessary to substantially compress the entire surface of the plate-like portion 14 as in the prior art. Need not be particularly large.

When the molding is completed in this way, the elevator is raised toward the position shown in the left half of FIG. At this time, the work W initially held by the groove forming punch 7
01 comes off, and then the punch 7 that comes off easily comes off due to the inclination of both sides of the trapezoidal side surface of the ridge 71 of the groove forming punch 7. Thereafter, the work W is paid out by raising the pad 92 as in the conventional case.

As described in detail above, according to the molding apparatus and the molding method using the same, the groove forming punch 7 is provided with the groove forming protrusions 71, so that the protrusions 71 When forming the groove 18 in the vicinity of the corner portion where the portion 11 and the plate portion 14 are connected, not only can the material of the material be prevented from flowing to the outer diameter side of the plate portion 14, but also to the inner diameter side toward the corner portion. Positively plastic flow,
Only by providing the groove forming ridge 71 on the punch 7, the corner radius of the press-formed part can be reduced. Furthermore,
The inclination of the trapezoidal side surface of the ridge 71 on the corner portion side promotes the extruding of the meat of the material in the corner direction and improves the flow of the meat, so that the corner radius can be further reduced. Also, due to the inclination of both sides of the trapezoidal side surface of the ridge 71,
The removal of the punch 7 is improved, and the dispensing of the formed part after processing is facilitated. Further, since the upper base of the trapezoid of the ridge 71 is flat, the durability of the ridge of the punch 7 is improved.

As described above, the present invention has been described in detail based on one embodiment. However, the present invention is not limited to the disclosed contents of the above embodiment, and various details can be set within the scope of the claims. Needless to say, the present invention can be implemented by changing the specific configuration.

[Brief description of the drawings]

FIG. 1 is an axial sectional view showing an embodiment of a press-formed part to which the present invention is applied.

FIG. 2 is a partial cross-sectional view in a cross-axial direction showing a state where the press-formed part is assembled into an automatic transmission.

FIG. 3 is a longitudinal sectional view showing the configuration of a molding apparatus to which the present invention is applied, including its operation.

FIG. 4 is a processing explanatory view showing the forming method of the present invention step by step.

FIG. 5 is an axial sectional view showing a drum of a friction engagement device of a conventional automatic transmission and its related parts.

FIG. 6 is a processing explanatory view showing a conventional method of forming a corner portion of a press-formed part.

FIG. 7 is a processing explanatory view showing another method of forming a corner portion of a conventional press-formed part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drum-shaped member (press-formed part) 7 Groove forming punch 8 Die 11 Cylindrical part 14 Plate-shaped part 18 Groove 71 Convex L bent part R Corner radius (corner part)

Claims (7)

[Claims] 1. A press-formed part having a cylindrical portion and a plate-shaped portion, wherein a groove formed by a press is formed on a plate-shaped portion near an outer corner of a bent portion where the cylindrical portion and the plate-shaped portion are interconnected. A press-formed part characterized by being formed. 2. The press-formed part according to claim 1, wherein the groove is located on an extension of an outer peripheral surface of the cylindrical portion. 3. The press-formed part according to claim 1, wherein the groove is formed around a corner portion. 4. The press-formed part according to claim 1, wherein said press-formed part is a drum-shaped member used for a friction engagement device of an automatic transmission. 5. A method for forming a press-formed part using a punch and a die, wherein a plate-shaped part connected to the cylindrical part is pressed against the die with a punch while supporting the inner peripheral side of the cylindrical part of the formed part with the punch. Forming a groove on a plate-like portion near a corner at an outer corner side of a bent portion where the cylindrical portion and the plate-like portion are connected to each other at the time of pressing by press-fitting a punch. 6. An apparatus for forming a press-formed part by using a punch and a die, wherein:
A molding device, characterized in that a convex portion for forming a groove is provided on a plate-like portion near an outer corner of a bent portion where a cylindrical portion and a plate-like portion of the molded part are connected to each other. 7. The molding apparatus according to claim 6, wherein the ridge has a trapezoidal cross section with the side facing the die as an upper bottom.