JP2009050912A - Cylindrical body manufacturing method and drawn cylindrical body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical body manufacturing method enabling a cylindrical body to have the desired thickness. <P>SOLUTION: A motor yoke manufacturing method provides a substantially bottomed cylindrical motor yoke from a plate material by performing multi-stage drawing processes using a die and a punch. In a partial thickness-increasing drawing process to be performed as one of the multi-stage drawing processes, the outer circumference of only a bottom part side of a workpiece is reduced while suppressing the axial elongation (the material flow) of the workpiece by a cushion plate 21 (having the axial length being substantially same as that of the workpiece in the previous stage), the punch 22 and the die 23 and thus, a partially thickness-increased intermediate yoke 11e with the thickness of only the bottom part side in the axial direction of the workpiece being increased can be obtained. Thereafter, the motor yoke is obtained by performing a process substantially similar to a general known drawing process (a poststage drawing process). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a cylindrical body such as a motor yoke and a cylindrical body for a drawn product.

Conventionally, as a manufacturing method of a cylindrical body for obtaining a substantially bottomed cylindrical cylindrical body such as a motor yoke provided in a rotating electric machine, a multi-stage drawing process is performed by using a die and a punch from a plate-shaped material. There is a method of obtaining a desired tubular body as a gradually elongated tubular body. And as a manufacturing method of such a cylindrical body, there exists a method provided with the thickening drawing process which increases the plate | board thickness of the cylinder part of the cylindrical body in the middle of manufacture entirely (for example, refer patent document 1). .
Japanese Patent No. 3415033

  However, the cylindrical body (drawn product cylindrical body) obtained by the manufacturing method as described above has a problem that the plate thickness of the cylindrical portion becomes thinner toward the bottom side in the axial direction. In the experimental results, the plate thickness increased 1.3 times from the bottom side to the opening side. This axial thickness difference causes, for example, a large amount of material for the motor yoke and an increase in weight. That is, in the motor yoke, if there is a thin plate portion, there is a concern about magnetic saturation, so it is necessary to secure the plate thickness also on the bottom side, and then the plate on the opening side where the plate thickness is thicker than the bottom side. Thickness becomes excessive, and as a result, waste is generated, resulting in a large amount of material and an increase in weight.

The present invention has been made to solve the above problems, and a first object of the present invention is to provide a method of manufacturing a cylindrical body capable of setting the plate thickness of the cylindrical body to a desired thickness. There is.
A second object is to provide a drawn product cylindrical body capable of reducing waste.

  The invention according to claim 1 is a method of manufacturing a cylindrical body that obtains a substantially bottomed cylindrical cylindrical body from a plate-shaped material by performing a multistage drawing process with a die and a punch. At least one of these drawing processes was a partial thickening drawing process for increasing the thickness of only a part of the cylindrical body in the axial direction during the production.

  According to the invention, in the partially thickening drawing process performed as at least one of the multistage drawing processes, the thickness of only a part of the cylindrical body in the axial direction is increased during the manufacturing process. The plate thickness of the cylindrical body can be set to a desired thickness.

  According to a second aspect of the present invention, in the method for manufacturing a cylindrical body according to the first aspect, the partial thickening drawing step includes an outer periphery of the cylindrical body while suppressing an axial extension of the cylindrical body. By reducing the thickness, the thickness of the portion is increased.

  According to the invention, in the partial thickening drawing process, the outer periphery of the cylindrical body is reduced while the axial extension of the cylindrical body is suppressed, so that the plate thickness of that part is increased. If it does in this way, the manufacturing method of Claim 1 can be performed more concretely easily.

  According to a third aspect of the present invention, in the method for manufacturing a cylindrical body according to the first or second aspect, the partial thickening drawing step is a plate only on the bottom side in the axial direction of the cylindrical body during the manufacturing. Increase thickness.

  According to the invention, in the partial thickening drawing process, the plate thickness only on the bottom side in the axial direction of the cylindrical body during the manufacturing is increased, and therefore the partial thickening drawing process is not performed (prior art). Compared to the above, it is possible to reduce the difference in plate thickness in the axial direction based on the thinning of the bottom side.

According to a fourth aspect of the present invention, in the cylindrical body manufacturing method according to the third aspect, the cylindrical body is a motor yoke in which a permanent magnet is fixed to an inner peripheral surface.
According to the present invention, the axial thickness difference in the motor yoke can be reduced compared with the case where the partial thickening drawing process is not performed. The material and weight of the yoke can be reduced to the minimum.

  The invention according to claim 5 is an axially intermediate portion in a drawn product cylindrical body that is made into a substantially bottomed cylindrical shape from a plate-like material by performing a multistage drawing process with a die and a punch. Has a maximum value of the plate thickness.

  According to the present invention, since the plate thickness has a maximum value in the middle portion in the axial direction, for example, the plate thickness difference in the axial direction is reduced as compared with the conventional one in which the plate thickness increases from the bottom side toward the opening side. It is possible to reduce the size, and it is possible to reduce waste. In addition, this drawing processed product cylindrical body is easily manufactured by the manufacturing method of the cylindrical body according to any one of claims 1 to 4.

According to invention of Claims 1-4, the manufacturing method of the cylindrical body which can make plate | board thickness of a cylindrical body desired thickness can be provided.
Further, according to the invention described in claim 5, it is possible to provide a drawn product cylindrical body capable of reducing waste.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, a motor yoke 1 as a cylindrical body (drawn processed product cylindrical body) provided in a rotating electric machine such as a DC motor is subjected to a multistage drawing process described later with a die and a punch. In this way, the plate-shaped material has a substantially bottomed cylindrical shape. Specifically, the cylindrical cylindrical portion 1a, the bottom portion 1b closing one end thereof, and the flange portion 1c extending radially outward from the other end (open end) Is provided.

  The permanent magnet 2 is fixed to the inner peripheral surface of the cylindrical portion 1a of the motor yoke 1. In addition, an armature core around which a winding (not shown) is wound is rotatably provided inside the motor yoke 1.

Next, a method for manufacturing the motor yoke 1 will be described with reference to FIGS.
First, as shown in FIGS. 2A to 2D, a disk-shaped plate material (not shown) is shown by performing first to fourth drawing processes using a general known die and punch (not shown). Gradually (in the order of the intermediate yokes 11a, 11b, 11c, and 11d), the intermediate yoke 11d is obtained. In each process, a die having a smaller (diameter) hole than the previous stage in order to make the outer periphery smaller than the previous stage work (intermediate yokes 11a to 11c), and the axial direction from the previous stage work A punch that protrudes larger than the previous stage is used so as to promote the extension of the first step.

  Next, as shown in FIG. 3, a plate which is a part of the workpiece (the intermediate yoke 11d (see FIG. 2D)) in the axial direction and is only on the bottom side by the cushion plate 21, the punch 22 and the die 23. A partial thickening drawing process for increasing the thickness is performed to obtain a partial thickened intermediate yoke 11e.

  Specifically, the cushion plate 21 is formed in a plate shape on which a work (the intermediate yoke 11d (see FIG. 2D)) can be placed, and a through hole 21a is formed in the center thereof. The punch 22 is formed in a substantially cylindrical shape that can protrude upward from the through hole 21a. The axial length of the punch 22 is substantially the same as the axial length of the intermediate yoke 11d (see FIG. 2D) in a state where the punch 22 protrudes to the maximum from the through hole 21a (see FIG. 3) (ie, The length is substantially the same as the punch used when forming the intermediate yoke 11d, and only the tip shape is slightly different in this embodiment. The die 23 has a throttle hole 23a (diameter) smaller than the outer circumference (diameter) of the intermediate yoke 11d in order to reduce the outer circumference only on the bottom side in the axial direction of the intermediate yoke 11d (see FIG. 2D). Have. In addition, a cylindrical support portion 23c is formed at the lower end (lower end in FIG. 3) of the die 23 of the present embodiment, which communicates with the throttle hole 23a and has a large-diameter hole 23b having a diameter larger than that of the throttle hole 23a. Has been. The axial length of the support portion 23c is approximately half of the axial length of the intermediate yoke 11d. When the support portion 23c abuts the cushion plate 21 in the axial direction as shown in FIG. Any further downward movement of is restricted.

  As shown in FIG. 3, the support portion 23 c abuts the cushion plate 21 with the die 23 against the cushion plate 21 and the punch 22 on which the workpiece (the intermediate yoke 11 d (see FIG. 2D)) is placed. Down (movable in the axial direction). As a result, by reducing the outer circumference of only the bottom side of the workpiece while suppressing the axial extension of the workpiece, the thickness of the portion is increased and the partially thickened intermediate yoke 11e is obtained. That is, in this step, the axial length of the punch 22 is substantially the same as the axial length of the intermediate yoke 11d (see FIG. 2D), and the lower end of the intermediate yoke 11d is brought into contact with the cushion plate 21. The die 23 is lowered in a state where the axial extension (flow of meat) is suppressed, and the outer periphery (diameter) only on the bottom side is reduced in the throttle hole 23a, so that the plate thickness is increased in this portion. In other words, in this process, the extension of the workpiece in the axial direction is not promoted as in the first to fourth drawing processes, and the meat is reduced while suppressing the axial extension (flow of meat). Since it is made to concentrate on the bottom side, the plate thickness is increased in this portion. In addition, the increase in the plate thickness in the partial thickening drawing process includes not only the case where the plate thickness is increased more than the material but also the case where only the reduction in the plate thickness due to the drawing process is suppressed.

  Next, as shown in FIG. 4, the cushion plate 31, punch 32, and die 33 reduce the outer circumference (diameter) of the workpiece (the partially thickened intermediate yoke 11e (see FIG. 3)) and increase the axial length. A lengthening step for the subsequent stage is performed to obtain the motor yoke 1.

  Specifically, the cushion plate 31 is formed in a plate shape on which a work (partial thickening intermediate yoke 11e (see FIG. 3)) can be placed, and a through hole 31a is formed in the center thereof. The punch 32 is formed in a substantially cylindrical shape that can protrude upward from the through hole 31a. The axial length of the punch 32 is set to be longer than the axial length of the partial thickening intermediate yoke 11e (see FIG. 3) in a state where the punch 32 protrudes to the maximum from the through hole 31a (see FIG. 4). . The die 33 is smaller than the outer circumference (diameter) at the bottom of the partial thickening intermediate yoke 11e in order to make the entire outer circumference in the axial direction of the partial thickening intermediate yoke 11e (see FIG. 3) constant. ) It has a throttle hole 33a.

  Then, as shown in FIG. 4, the die 33 is lowered with respect to the cushion plate 31 and the punch 32 on which the workpiece (partial thickening intermediate yoke 11e (see FIG. 3)) is placed (movable in a direction approaching the axial direction). Let As a result, the outer circumference (diameter) of the workpiece is reduced (a constant size in the axial direction) and the axial length is increased, whereby the motor yoke 1 is obtained. That is, this process is substantially the same as a general known drawing process, and the thickening drawing process is performed to the end on the opening side where the plate thickness increases only by performing the known drawing process. The motor yoke 1 is obtained.

  The plate thickness of the (cylindrical portion 1a) of the motor yoke 1 manufactured in this way has a maximum value X of the plate thickness at the intermediate portion in the axial direction, as shown in FIG. FIG. 5 is a height (axial position) -plate thickness characteristic diagram, and shows a tube from the position near the flange 1c (left end in FIG. 5) to the position near the bottom 1b (right end in FIG. 5). The plate | board thickness in the shape part 1a is illustrated. The axial position of the maximum value X corresponds to the axial position where the plate thickness is increased during the partial thickening drawing process, that is, the axial length of the support portion 23c, and the axial length of the support portion 23c. It is known that the axial position of the maximum value X is shifted by changing the height, and the plate thickness of the maximum value X increases as it approaches the flange portion 1c side. In the present embodiment, the plate thickness at the maximum value X is large so that the minimum plate thickness is secured in the axial range in consideration of the axial position where the permanent magnet 2 is fixed. The axial length of the support portion 23c is set so that the plate thickness at the maximum value X does not become too large in consideration of the problem of biting into the die (punch 32 and die 33) due to being too large.

Next, characteristic effects of the above embodiment will be described below.
(1) In a partial thickening drawing process performed as one of multistage drawing processes (first to fourth drawing processes, partial thickening drawing process, and subsequent drawing process), By reducing the outer circumference of only the bottom side of the workpiece while suppressing the axial extension of the workpiece (intermediate yoke 11d), the thickness of only the bottom side in the axial direction of the workpiece is increased. As a result, the motor yoke 1 has a maximum value X of the plate thickness in the middle portion in the axial direction, and the plate thickness difference in the axial direction is smaller than when the partial thickening drawing process is not performed (prior art). The thickness of the motor yoke 1 (its cylindrical portion 1a) can be made closer to a desired thickness. As a result, in the present embodiment, compared to the case where the partial thickening drawing process is not performed (prior art), for example, the motor yoke 1 avoiding magnetic saturation can be reduced while the waste of the motor yoke 1 can be reduced. The material and weight can be reduced to the minimum.

The above embodiment may be modified as follows.
In the above embodiment, the partial thickening drawing process increases the plate thickness only on the bottom side in the axial direction of the workpiece (intermediate yoke 11d) as a cylindrical body during manufacture, but is not limited thereto. It is good also as a partial thickness reduction drawing process (manufacturing method of a cylindrical body) which increases the plate | board thickness of the other part of the axial direction of the cylindrical body in the middle of manufacture. For example, partial thickening drawing may be performed in a plurality of stages.

  For example, as shown in FIG. 6, in addition to the bottom side in the axial direction of the cylindrical body 51, a partial thickening drawing process (step) for increasing the plate thickness may be performed on the opening side away from the axial side. Specifically, after the partial thickening drawing process similar to the partial thickening drawing process of the above embodiment is performed on the bottom side, the subsequent drawing process similar to the subsequent drawing process of the above embodiment is performed in the axial direction. To the middle part, the outer circumference (diameter) of the workpiece is reduced and the axial length is increased (without suppressing), and the partial thickening drawing process (shaft) similar to the partial thickening drawing process of the above embodiment is further performed. The step of reducing the outer circumference while suppressing the extension in the direction) may be performed on the opening side. In this way, the plate thickness can be increased on the bottom side and the opening side in the axial direction of the cylindrical body 51 (compared to the case where the partial thickening drawing process is not performed). The tubular body 51 of this example is desired to have the above-described thickness, and is not limited to the motor yoke 1. That is, the above-described embodiment and this example may be other cylindrical body manufacturing methods.

  In the above embodiment, the support portion 23c is formed on the die 23. However, the present invention is not limited to this, and it is assumed that the support portion 23c is not formed. A partially thickened intermediate yoke 11e similar to that of the above-described embodiment may be obtained by lowering to an intermediate position of (the intermediate yoke 11d (see FIG. 2D)) and stopping (position control).

Sectional drawing of the motor yoke and permanent magnet of this Embodiment. (A)-(d) Sectional drawing of an intermediate yoke. Explanatory drawing for demonstrating the partial thickening drawing process of this Embodiment. Explanatory drawing for demonstrating the back | latter stage drawing process of this Embodiment. The height (axial direction position) -plate thickness characteristic view in the motor yoke of the present embodiment. Sectional drawing of the cylindrical body of another example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Motor yoke (cylindrical body (drawn article cylindrical body)), 2 ... Permanent magnet, 11d ... Intermediate yoke (cylindrical body in the middle of manufacture), 22, 32 ... Punch, 23, 33 ... Die, 51 ... Tubular body (drawn product tubular body).

Claims (5)

In the method of manufacturing a cylindrical body that obtains a substantially bottomed cylindrical body from a plate-like material by performing a multi-stage drawing process with a die and a punch,
At least one of the multi-stage drawing processes is a partial thickening drawing process for increasing the thickness of only a part of the cylindrical body in the axial direction during manufacture. A method of manufacturing a body. In the manufacturing method of the cylindrical object according to claim 1,
The partial thickening drawing step increases the plate thickness of the cylindrical body by reducing the outer circumference of the cylindrical body while suppressing the axial extension of the cylindrical body. Production method. In the manufacturing method of the cylindrical body according to claim 1 or 2,
The said partial thickness reduction drawing process increases the plate | board thickness only in the axial bottom part side of the said cylindrical body in the middle of manufacture, The manufacturing method of the cylindrical body characterized by the above-mentioned. In the manufacturing method of the cylindrical object according to claim 3,
The cylindrical body is a motor yoke in which a permanent magnet is fixed to an inner peripheral surface. In a drawn product cylindrical body that is made into a substantially bottomed cylindrical shape from a plate material by performing a multistage drawing process with a die and a punch,
A drawn product cylindrical body having a maximum value of a plate thickness at an intermediate portion in an axial direction.

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