JPS6160742B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for forming a fitting surface of a drawn or burred steel plate product, and is particularly effective when applied to the forming of stators of electric motors, bearing housing parts, etc. be.

Although this invention can be applied to various fitting surface forming methods, for convenience of explanation, a steel plate frame of an electric motor will be described.

As a conventional method for manufacturing a steel plate frame, there is a drawing method using a press having the configuration shown in FIG. In this conventional example, a knockout 3 is attached to a die holder 1 via a spring 2, and is capable of vertical movement. The die 4 is fixed to the die holder 1. The wrinkle presser 5 is supported by a dicing rod 6 pushed up by a dicing device of a press machine, and is capable of vertical movement. A punch holder 7 fixes a punch 9 for squeezing a workpiece 8 serving as a steel plate frame.

Note that the figure shows the state after the aperture is finished.

The dicing rod 6 pushed up by the dicing device of the press, whose operation will be explained next, pushes up the wrinkle presser 5 and is adjusted to the same height as the punch 9. Now, when the work 8 is placed on the wrinkle presser 5 and the press ram descends, the work 8 is held between the die 4 and the wrinkle presser 5, and the work 9 is squeezed following the punch 9.

When the die 4 rises, the wrinkle press 5 which is being pushed up by the dicing device also rises and stops at the same height as the punch 9. Therefore, the knockout 3, which is pressurized by the spring 2, pushes out the workpiece 8 contained in the die 4.

An enlarged view of the work 8 squeezed in this manner is shown in FIG. In the conventional method, as shown in FIG. 2, when the workpiece 8 is drawn down to the inner diameter d, there is a difference between the maximum wall thickness t and the minimum wall thickness _t1 due to variations in the thickness of the workpiece 8, resulting in a tapered drawing shape.

For this reason, the workpiece 8 that becomes the conventional steel plate frame has been subjected to ironing after the above-mentioned drawing process in order to obtain high-precision fitting dimensions, but the drawn product (workpiece 8)
It is difficult to obtain high accuracy due to problems such as material variation, uneven wall thickness, and material quality. Therefore, in order to obtain high dimensional accuracy, cutting is performed after drawing. be.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional products, and its purpose is to obtain a highly accurate fitting surface only by press working.

An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 3 to 10, numeral 11 indicates a press-drawn workpiece. The punch 12 is a mold for shaping the inner diameter of a workpiece, has a protrusion 12a on its outer peripheral surface, which is a feature of the present invention, and is fixed to a punch holder 14 via a spacer 13.

The die 15 is a mold for forming the outer diameter of the workpiece 11.
It is fixed to the die holder 16.

A knockout plate 1 is provided on the inner diameter side of the die 15.
7 is attached to the die holder 16 by a hanging bolt 18 so as to be movable up and down with a spring 19 in between.

The wrinkle presser 20 is moved up and down by a dicing device of a press machine connected to a dicing rod 21 to take out the work 11 crimped to the punch 12 and is provided as a height adjustment plate for the work 11.

The pin 22 faces the dicing rod 21 so as to push it down in order to insert the work 11 into the punch 12. The die holder 16 and the punch holder 14 are movable up and down in a sliding relationship by a guide post 23 and a guide bush 24, and the punch 12 and die 15 are fixed concentrically.

FIG. 4 shows a mold for molding the workpiece 11, which was molded with the protrusion 11a in FIG. 3, into a predetermined fitting surface. A punch 31 for squeezing the inner diameter of the work 11 is fixed to a punch holder 32, and a die 33 for squeezing the outer diameter of the work 11 is fixed to a die holder 34. A knockout plate 35 is attached to the inner diameter of the die 33 by a hanging bolt 36 to a die holder 34 so as to be movable up and down with a spring 37 in between. Pin 38 attached to die 33
serves to push down the dicing rod 39 and lower the wrinkle presser 40 in order to insert the workpiece 11 into the punch 31. The dicing rod 39 is connected to the dicing device of the press machine, and can move up and down by pushing up the wrinkle presser 40 by applying a predetermined pressure. Die holder 34 and punch holder 32
can be moved up and down by a guide post 41 and a guide bush 42, and the punch 31 and die 33 are fixed concentrically.

In FIGS. 2 and 3, the sectional views on the right side of the center line show the state during molding, and the sectional views on the left side show the state before molding.

Next, to explain the operation shown in FIG.
is lowered, and the knockout putter 17 is placed in work 1.
1 to insert the workpiece 11 into the punch 12. Thereafter, the die 15 presses the workpiece 11, and as shown in FIG. 7, the projections 11a are formed on the inner surface of the workpiece 11 while squeezing the ironing allowance g and producing extra thickness into the relief grooves between the protrusions 12a of the punch 12.

After forming, the die 15 rises as the press rises, but the knockout plate 17 still presses the workpiece 11 under the pressure of the spring 19, so it remains in the punch 12. When the press further rises, the pin 22 fixed to the die 15
As the pressure rises, the dicing rod 21 rises and pushes up the wrinkle presser 20. Therefore, the workpiece 11 contained in the punch 12 is taken out and press work 1 is performed.
The process is finished.

Next, the workpiece 11 having the inner protrusion 11a formed thereon is machined to a predetermined fitting surface accuracy using an ironing die shown in FIG. The explanation will be given below.

The pin 38 pushes down the cushion rod 39 and lowers the wrinkle presser 40, and also lowers the knockout plate 3.
5 presses the work 11 to insert the work 11 into the punch 31. Since the punch 31 is machined to a predetermined fitting surface accuracy, the die 3 is then
3 presses the workpiece 11 and squeezes the protrusion 11a formed in the above step, the workpiece 11 has valleys formed between the protrusions 11a that can leave extra meat, so the squeezed extra meat is crushed. and flows into the valley. Then, as the press rises after forming, the die 33
moves up, but the knockout plate 35 still presses the workpiece 11 due to the pressure of the spring 19, so it remains in the punch 31, and as the press rises further, the pin 3 fixed to the die 33
3 rises, the dicing rod 39 rises and pushes up the wrinkle presser 40, and the workpiece 11 contained in the punch 31 is taken out, completing one step of the press operation.

The main part of the workpiece 11 formed in this way is the fifth
It is shown enlarged in FIG.

Conventional press-drawn products and the like were as explained in FIGS. 1 and 2, and it was difficult to obtain a high degree of production. However, in the method of the present invention, in order to form a highly accurate fitting surface, as shown in FIGS. By squeezing with the die 15, the excess material is plastically moved into the groove of the protrusion 12a of the punch 12, thereby preventing the material from moving in the axial direction due to squeezing. As a result, groove-shaped protrusions 11a are formed on the inner surface of the workpiece 11. Note that the angle, shape, and size of the protrusion 12a of the punch 12 vary depending on the thickness and size of the product material. Furthermore, since the amount of squeezing also differs depending on the conditions, it may be set appropriately.

Next, the protrusion 11a is squeezed using the method shown in FIG. Figure, 6th
The peaks of the protrusions 11a on the inner surface of the workpiece 11 shown in the figure are crushed, and the material plastically moves into the grooves in the valleys.
Therefore, the flow of material in the axial direction is prevented, and wall thickness variations and spring back during forming due to the ironing process are made uniform, making it possible to form a very precise fitting surface on the inner surface of the workpiece 11. can.

In the above embodiment, the press-drawn product (work)
We have explained how to improve accuracy on the inner diameter side of the die, but it is also possible to create a groove on the die side and tighten it later.It is also possible to create relief grooves on both the punch and die and tighten it later with the punch die to improve accuracy on both the inner and outer diameters. can. Additionally, the surface without relief grooves has improved accuracy and can be used as a mating surface. Furthermore, it can be easily applied to improve the accuracy of the inner and outer diameters of cold forging and to square shapes other than circular ones if it is cylindrical.

As described above, according to the present invention, it is possible to improve the dimensional accuracy of the inner and outer diameters of the fitting surface in press working,
There are great effects such as being able to obtain a mating surface with high production speed and high precision.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional drawing die, Fig. 2 is an explanatory diagram showing the relationship between the drawn workpiece of Fig. 1, a die, and a punch, and Fig. 3 shows an embodiment of the present invention. , a cross-sectional view of the press die structure used in the first step of forming the protrusion, FIG. 4 is a cross-sectional view of the press die structure used in the second step of crushing the top of the protrusion, and FIG. 5 is a cross-sectional view of the press die structure used in the second step of crushing the top of the protrusion. FIG. 6 is an enlarged cross-sectional view of the workpiece, FIG. 7 is an enlarged longitudinal cross-sectional view of the main part during the first step, and FIG. 8 is an enlarged longitudinal cross-sectional view of the main part during the second step. Enlarged vertical cross-sectional view,
FIG. 9 is an enlarged longitudinal cross-sectional view of the main part of the workpiece after the second step, and FIG. 10 is an enlarged cross-sectional view of the main part of the workpiece after the second step. In the figure, 4, 15, 33 are dies, 8, 11 are workpieces, 9, 12, 31 are punches, 11a is a protrusion, 1
2a is a protrusion. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 In a method of forming a cylindrical fitting surface, a first punch having a protrusion on the peripheral edge is inserted into a cylindrical fitting part of a cylindrical workpiece, and is pressed by a die to form the fitting surface. a first step of forming a large number of protrusions on the fitting portion; and a second punch having an outer diameter corresponding to the bottom of the groove formed in the fitting portion of the workpiece by the step is inserted into the fitting portion. and a second step of crushing the tops of the protrusions by pressing with a die.