JP4885893B2 - Stepped shaft manufacturing method, armature shaft manufacturing method, and stepped shaft molding apparatus - Google Patents

Description

  The present invention relates to a method for manufacturing a shaft with a stepped portion, a method for manufacturing an armature shaft, and a molding device for a shaft with a stepped portion. The present invention relates to a stepped shaft manufacturing method and an armature shaft manufacturing method that can be formed with high quality and low cost, and a stepped shaft molding apparatus.

Conventionally, a long-axis object in which the diameter of the tip (not only indicating the exact circular diameter but also including the longest opposing size such as an ellipse or a polygon) is smaller than the diameter of the main body is used. In manufacturing, it has been difficult to process the tip portion having a reduced diameter with high accuracy.
Thus, a method for manufacturing a long-axis object in which the diameter of the tip portion is formed smaller than the diameter of the main body portion has been proposed (see, for example, Patent Document 1).

Patent Document 1 discloses a method for manufacturing a stepped shaft.
In the narrowing processing device described in Patent Document 1, a long bar-shaped material that has been subjected to imposition by a forging processing device is loaded into a die, and the end portion on the loading opening side of the loaded long bar-shaped material is formed. Narrowing is performed by pressing with a punch.
A slate hole with a smaller diameter than the charging port is formed coaxially at one end of the charging port of the die (the end opposite to the charging opening side of the material), and the material is pressed by the die. Then, one end of the long rod-shaped material is plastically deformed into a shape that matches the shape of the slate hole.
That is, one end of the long bar-shaped material is narrowed down to form a stepped shaft.

JP 2000-202564 A

However, in the case of an apparatus based on the principle of plastically changing the shape of the other end side by pressing one end with a punch in this way, it is possible to effectively carry out drawing processing of the tip portion in the case of a short object. However, there is a problem that the longer the length, the more difficult the processing becomes.
That is, if the material is long, the pressing force of the punch is not effectively transmitted to the tip, and there is a problem that the plastic deformation of the tip is not performed sufficiently.
For example, as shown in FIG. 8, the ratio of effective pressure at each point is shown as follows: A 'point is about 50%, B' point is about 30%, C 'point is about 15%, D' point Thus, the pressure at the plastic deformation portion (tip portion) is insufficient, so that the plastic deformation of the tip portion cannot be performed reliably.

  An object of the present invention is to solve each of the above-mentioned problems, and in the process of narrowing the tip when manufacturing a stepped shaft in which the diameter of the tip is smaller than the main body, the tip is sufficiently narrowed. A method of manufacturing a stepped shaft and an armature shaft capable of forming a stepped shaft with a narrowed tip at high quality and low cost, capable of reliably performing a narrowing process by transmitting a processing pressure It is in providing the manufacturing method of this, and the shaping | molding apparatus of the shaft with a step part.

According to the method for manufacturing a shaft with a step portion according to the present invention, the above-described problem is a method for manufacturing a shaft with a step portion having a large diameter portion and a small diameter portion. A first mold in which a first molding hole supported and movable in the axial direction and capable of sliding a pressure pin is formed in the internal axial direction; and an end face in the axial direction of the first mold; A second molding hole that is disposed to face each other and is configured as a gap that aligns with the tapered portion that connects the large diameter portion and the small diameter portion, and the large diameter portion and the small diameter portion. A second mold formed in the axial direction, and a first elastic member for transmitting an elastic force in the axial direction is disposed on the other axial end surface of the first mold. One end of the second mold is fixed to the axial end surface of the second mold not facing the first mold. The other end of the second elastic member that transmits sexual force is disposed, and the first mold and the second mold are opposed to each other with a predetermined gap, and the first molding hole The second molding hole is disposed at a communicating position, and the small-diameter portion of the second molding hole is disposed on the second elastic member side. A first step of inserting a rod-shaped member to be molded; and pressing and contracting the first elastic member toward the first mold side, and the pressure pin is moved into the first molding hole. The second mold is slid toward the axial direction end portion on the side where the second mold is disposed, and the first mold is moved to the second mold by the pressing force of the first elastic member. A third step of contacting the first mold, and further contracting the first elastic member to press the first mold against the second mold, and The pressing force applied from the first elastic member is transmitted, and the second elastic member moves the second die from the first die by a restoring force with respect to the pressing force transmitted from the second die. While acting to push back in the direction in which it is disposed, the end of the pressure pin is brought into pressure contact with the object to be molded, and the object to be molded is pressed toward the small diameter part, and the restoring force and the pressure pin And a fourth step of forming a shape matching the tapered portion and the small diameter portion at the tip portion of the molding object by the pressing force.

  In addition, the above-described problem is a step-shaft forming device having a large-diameter portion and a small-diameter portion according to the step-shaft shaft forming device according to the present invention. A pressure pin that presses the rod-shaped workpiece, and a first molding hole that is supported by a guide and is movable in the axial direction and in which the pressure pin can slide is formed in the internal axial direction. A taper-like shape is disposed opposite to one end face in the axial direction of the mold and the first mold, and connects the large-diameter portion and the small-diameter portion and the large-diameter portion and the small-diameter portion inside. A second mold hole configured as a gap that matches the taper portion is formed in the axial direction, and a second mold is disposed on the other end surface of the first mold in the axial direction. The first elastic member to be transmitted and one end of the first elastic member are fixed, and the other end is opposite to the first mold of the second mold And a second elastic member that is disposed on an end surface on the non-side and transmits an elastic force in the axial direction, and further contracts the first elastic member so that the first mold is The pressing force applied from the first elastic member to the second mold is transmitted to the second mold, and the pressing force transmitted from the second mold is transmitted to the second elastic member. The second mold is caused to push back in the direction in which the first mold is disposed by a restoring force to the mold, and the end of the pressure pin is inserted into the second molding hole. A shape that presses the molding object toward the small diameter portion by pressing against the object, and is aligned with the tapered portion and the small diameter portion at the tip of the molding object by the restoring force and the pressing force of the pressure pin. It is solved by forming.

In the present invention, the first step of inserting the rod-shaped member into the second molding hole formed in the second mold, and pressing the first mold side by the first elastic member, A second step of sliding the pressure pin toward the axial end portion on the side where the second die is disposed in the first molding hole formed in the first die; The molding preparation stage is realized by performing the third step of bringing the first mold into contact with the second mold with the pressing force of the one elastic member.
Next, by performing the fourth step which is a characteristic configuration of the present invention, the stepped portion of the shaft is surely molded.
In the fourth step, the first elastic member is further contracted to press the first mold against the second mold, and the pressing force applied from the first elastic member is transmitted to the second mold. The second elastic member causes the second die to be pushed back in the direction in which the first die is disposed by the restoring force against the pressing force transmitted from the second die, and the end portion of the pressure pin is In this step, the workpiece is pressed against the small diameter portion and pressed toward the small diameter portion, and the tapered portion and the small diameter portion are formed at the tip portion of the molded material by the restoring force and the pressing force of the pressure pin.

That is, in the fourth step “step with stepped portion forming step (squeezing step)”, one end of the object to be molded (the end on the side where the stepped portion is not formed) is pressed with a pressure pin. A pressure is applied, and a pressing force applied from the second elastic member (due to a restoring force of the second elastic member) is applied to the other end portion of the molding object.
In other words, the object to be molded is plastically deformed into a shape in which the tip is aligned with the small diameter portion by being pushed in the direction of the small diameter portion (that is, the stepped portion forming direction) by the pressing force applied from one end side from the pressure pin. The rod-shaped member that is being advanced by being pushed in the large-diameter direction (that is, the direction opposite to the direction of the pressing force applied by the pressure pin) by the pressing force applied from the second elastic member. Promotes plastic deformation.
More specifically, the object to be molded is a mold (second molding) that is sandwiched from both ends in the axial direction by the pressing force applied by the pressure pin and the pressing force applied by the second elastic member. To the hole).
For this reason, the pressure on the small-diameter portion side where the pressure applied from the pressure pin is in a low state is reduced by being disposed at a position separated from the pressing point (end portion on the large-diameter side) of the pressure pin. It can be compensated by the pressing force (restoring force) of the second elastic member.
Moreover, according to the shaping | molding apparatus of the shaft with a step part which concerns on this invention, the said process can be implemented effectively.

Therefore, it is possible to reliably ensure the processing pressure at the tip of the object to be molded which is a long-axis object, and it is possible to provide a high-strength part by plastic processing.
In addition, since it is possible to reduce the tip of a workpiece that is a long-axis object, productivity can be improved by high-speed machining, and quality can be stabilized by stabilizing the accuracy of the tip.
In addition, since secondary processing steps such as knurling and cutting are not required, manufacturing costs can be reduced, and shape changes and volume fluctuations can be flexibly handled, reducing capital investment. can do.
As described above, it is possible to realize a significant reduction in manufacturing cost and to provide a high quality and low cost stepped shaft.

  In the first aspect of the invention, the other end of the first elastic member connected to the first mold is fixed to a pressing member to which a pressing force is applied from the outside. The pressure pin is disposed on the surface of the pressing member on the side to which the first elastic member is connected. In the second to third steps, the pressing member is When a pressing force is applied to the first elastic member and the pressure pin through the operation, it is possible to improve the efficiency of the operation.

  Further, according to the method for manufacturing an armature shaft according to the present invention, there is provided a method for manufacturing an armature shaft in which worm teeth are formed on the small diameter portion of a stepped shaft having a large diameter portion and a small diameter portion. The stepped shaft molding apparatus is supported by a guide and is movable in the axial direction, and a first mold in which a first molding hole in which a pressure pin is slidable is formed in the inner axial direction. The taper-shaped taper portion that is disposed to face the one end surface in the axial direction of the first mold and connects the large-diameter portion and the small-diameter portion and the large-diameter portion and the small-diameter portion inside. And a second mold formed in the axial direction with a second molding hole configured as a gap that matches the gap, and an elastic force is transmitted in the axial direction to the other axial end surface of the first mold. A first elastic member is disposed and faces the first mold of the second mold One end is fixed to the axial end surface on the non-side, and the other end of the second elastic member that transmits the elastic force in the axial direction is disposed. The first mold and the second mold And facing with a predetermined gap, the first molding hole and the second molding hole are disposed in a communicating position, and the small-diameter portion of the second molding hole is: A first step of inserting a rod-shaped member to be molded into the second molding hole, and pressing the first elastic member toward the first mold side. And the second step of sliding the pressure pin toward the axial end portion on the side where the second mold is disposed in the first molding hole, A third step of bringing the first mold into contact with the second mold by the pressing force of the first elastic member; and further collecting the first elastic member. Then, the first die is pressed against the second die, the pressing force applied from the first elastic member is transmitted to the second die, and the second elastic member is moved to the second die. The second die is pushed back in the direction in which the first die is arranged by the restoring force against the pressing force transmitted from the die, and the end of the pressure pin is pressed against the workpiece. Then, the object to be molded is pressed toward the small-diameter portion, and a shape that matches the tapered portion and the small-diameter portion is formed at the distal end portion of the object to be molded by the restoring force and the pressing force of the pressure pin. This is solved by including a fourth step and a fifth step of forming a worm in the small diameter portion by a rolling device provided with a rolling die.

Thus, according to the present invention, by rolling the small diameter portion of the stepped shaft formed in the same manner as in the invention according to claim 1, a worm is formed in the small diameter portion, and the armature shaft is It can be created easily and efficiently.
In addition, this rolling process can squeeze and form a material that is thinner than the outer shape of the product, which can reduce the waste of raw materials compared to the cutting process that cuts the shape and contributes to the reduction of manufacturing costs. .

According to the present invention, in narrowing the tip when manufacturing a shaft with a stepped portion whose diameter is smaller than that of the main body, a sufficient narrowing pressure is transmitted to the tip to ensure the narrowing. Can be done.
In addition, since the device according to the present invention has a simple configuration and can reliably narrow the tip portion, it is possible to form a stepped shaft with a narrowed tip at high quality and at low cost. is there.
In addition, since secondary processing steps (knurling process, cutting process, etc.) are unnecessary, it is possible to reduce manufacturing costs, flexibly respond to shape changes and quantity fluctuations, and capital investment. It is possible to suppress the manufacturing cost.
Further, by forming the worm by rolling the small diameter portion of the shaft with the stepped portion, the armature shaft can be easily formed at a low cost.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Note that the configuration described below does not limit the present invention and can be variously modified within the scope of the gist of the present invention.
In the present embodiment, in the narrowing of the tip when manufacturing the shaft with the stepped portion whose diameter is smaller than that of the main body, a sufficient narrowing pressure is transmitted to the tip to ensure the narrowing. And a stepped shaft manufacturing method and an armature shaft manufacturing method, and a stepped shaft molding apparatus capable of forming a stepped shaft with a narrowed tip at high quality and low cost (Hereinafter simply referred to as “molding apparatus S”).

  1 to 5 show an embodiment of the present invention. FIG. 1 is an explanatory diagram showing a molding apparatus, FIG. 2 is an explanatory diagram showing the operation of the molding apparatus, and FIG. 3 is an operation of the molding apparatus. FIG. 4 is an explanatory view showing the pressing principle of the molding apparatus, FIG. 5 is an explanatory view showing the pressure distribution of the molding apparatus, FIG. 6 is an explanatory view showing the rolling process, and FIG. 7 is an explanatory view of the armature shaft. .

FIG. 1 shows a molding apparatus S according to this embodiment.
As shown in FIG. 1, the molding apparatus S according to this embodiment includes a pressure pin 1, a first mold 2, a second mold 3, a pressing member 4, a first elastic member 5, a support member 6, a first member. 2 elastic members 7.
FIG. 1 is a partial cross-sectional view.

In the present embodiment, the characteristic configuration according to the present invention is mainly disclosed, and detailed control of the molding apparatus S, other configurations (for example, a guide member of the die), and the like are known narrowing devices. Since it is the same structure, illustration and description are abbreviate | omitted.
In the present embodiment, the molding object G is a rod-shaped member.
The material is carbon steel of S45C or less, the cross-sectional area reduction rate is set to about 35% to 65%, and the ratio of diameter to length (length / diameter) is set to about 15% to 25%. did.

The pressure pin 1 according to the present embodiment is a known pressure punch and presses one end side of the molding object G.
The first mold 2 according to this embodiment is a so-called die for molding, and a first molding hole 21 is formed at a substantially central portion thereof.
In the present embodiment, the first molding hole 21 is formed as a cylindrical hole extending in the axial direction.
Moreover, a substantially cylindrical first mold side first elastic member fixing portion 22 is formed on the position end surface side of the first mold 2 (the surface facing the pressing member 4 described later).

The second mold 3 according to the present embodiment is a so-called die for molding, and a second molding hole 31 is formed at a substantially central portion thereof.
In the present embodiment, the second molding hole 31 has a cylindrical long shaft portion 31a (corresponding to a large diameter portion), is coaxial with the long shaft portion 31a, and has a smaller diameter than the inner diameter of the long shaft portion 31a. A cylindrical tip portion 31c (corresponding to a small diameter portion), and a tapered portion 31b that connects the long shaft portion 31a and the tip portion 31c.

A second mold side second elastic member fixing portion 32 having a substantially cylindrical shape is formed on one end surface side of the second mold 3 (surface facing the support member 6 described later).
Note that the shapes of the first molding hole 21 and the second molding hole 31 are not limited to this, and the shape of the molding G is within a range that does not depart from the gist of the present invention, such as a shape that is squeezed in multiple steps. In addition, it may be formed in any manner according to the processed shape of the molding G.

The pressing member 4 according to the present embodiment includes a first pressing member 41 and a second pressing member 42.
The first pressing member 41 is a substantially cylindrical member, and is disposed on one end surface side (end surface on the first mold 2 side) in a state where the second pressing member 42 is in contact with the same axis. Yes.
On the one end face side of the second pressing member 42, a substantially cylindrical second pressing member side first elastic member fixing portion 42a having a smaller diameter than the second pressing member 42 is formed coaxially.

The one end side of the pressure pin 1 is fixed inside the first pressing member 41 and the second pressing member 42.
That is, by applying a force to the first pressing member 41 and the second pressing member 42, the pressing pin 1 moves in the direction in which the force is applied.
In the present embodiment, the first pressing member 41 and the second pressing member 42 are separated from each other, but the present invention is not limited to this, and the first pressing member 41 and the second pressing member are not limited thereto. 42 may be integrated.

The first elastic member 5 according to the present embodiment is a known spring, and both ends thereof are a first mold side first elastic member fixing part 22 formed on the first mold 2 and a second pressing member. The second pressing member side first elastic member fixing portion 42a formed on the member 42 is fixed to each.
That is, the pressing force from the second pressing member 42 is transmitted to the first mold 2 through the first elastic member 5.

The support member 6 according to the present embodiment is a substantially columnar member, and has a substantially cylindrical support member side second elastic member fixing portion on one end surface thereof (a surface on the side facing the second mold 3). 61 is formed.
The second elastic member 7 according to the present embodiment is a known spring, and both end portions thereof are connected to the second mold side second elastic member fixing portion 32 formed on the second mold 3 and the support member 6. It is respectively fixed to the formed support member side second elastic member fixing portion 61.
That is, transmission of force between the second mold 3 and the support member 6 is performed via the second elastic member 7.

The first die 2 and the pressing member 4 are covered with a punch case K1, and the second die 3 and the supporting member 6 are covered with a die case K2.
The punch case K1 is supported by a guide member (not shown) and is configured to be movable in the axial direction along the guide member.
Further, the first die 2 and the pressure pin 1 are slidable relative to each other, and the punch case K1 and the first die 2 are configured to slide integrally.

Next, the operation of the molding apparatus S according to this embodiment will be described with reference to FIGS.
In the following description, the end face on the side facing the second mold 3 among the axial end faces of the first mold 2 will be referred to as “surface D”, and the end face in the axial direction of the second mold 3 The end surface on the side facing the mold 3 of 1 is referred to as “surface E”.
The side on which the support member 6 is disposed is referred to as “front end”, and the side on which the first mold 2 and the pressing member 4 are disposed is referred to as “rear end”.

As shown in FIG. 2A, a predetermined clearance is formed between the surface D and the surface E in a state where the surface is not pressed.
That is, the surface D and the surface E are not in contact with each other and are in a separated state.
At the time of molding, as shown in FIG. 2 (b), the surface D and the surface E are in pressure contact, and the pressing force applied from the first pressing member 41 and the second pressing member 42 is the first elastic member 5. Is transmitted from the first mold 2 to the second mold 3, and at this time, due to the reaction of the second mold 3 contracting the second elastic member 7, the second mold 3 is It is pressed toward the rear end by the elastic member 7.

Further, the pressure pin 1 presses the rear end portion of the molding object G, and the tip portion of the molding object G is plastically deformed into a shape that matches the tip shape of the first molding hole 21. .
In addition, the front-end | tip part of the to-be-molded object G is comprised so that plastic deformation may be carried out until it contacts the edge part of a knockout pin. However, the configuration is not limited to this, and a stopper or the like may be disposed at a specified tip portion, or the deformation may be completed with a specified size by adjusting the pressing force.

Details of the operation of the molding apparatus S will be described in order with reference to FIG.
As described above, in the molding apparatus S according to the present embodiment, as shown in FIG. 3A, a predetermined clearance is formed between the surface D and the surface E when not pressed.
That is, the surface D and the surface E are not in contact with each other and are in a separated state. In this state, no pressure is applied to the molding apparatus S and the workpiece G.

In this state, the rear end portion of the molding object G inserted into the second molding hole 31 is pressed with the pressing pin 1.
As shown in FIG. 3B, the first mold 2 and the pressing member 4 are moved in the direction of the second mold 3, and the object to be molded is inserted into the first molding hole 21 formed in the first mold 2. Insert the rear end of G.
At this time, the first mold 2 slides integrally with the punch case K1.

When the sliding movement of the first die 2 and the punch case K1 is continued in this way, the surface D and the surface E come into contact with each other as shown in FIG.
In this state, the rear end portion of the workpiece G is not in contact with the front end portion of the pressure pin 1.
Next, as shown in FIG. 3D, the pressing force applied from the first pressing member 41 to the second pressing member 42 when the first pressing member 41 and the second pressing member 42 are further pressed in the distal direction. Is transmitted to the first mold 2 through the first elastic member 5 and is transmitted to the second mold 3 through the first mold 2.

Further, since the gap between the second pressing member 42 and the first mold 2 is reduced by the amount of the first elastic member 5 contracted, the front end portion of the pressure pin 1 is the rear end of the workpiece G. The pressing force is applied to the workpiece G from the pressing pin 1.
That is, the pressing force applied from the first pressing member 41 is applied from the second pressing member 42 to the second mold 3 through the first pressing member 41, the first elastic member 5, and the first mold 2 in this order. It is transmitted from the pressure pin 1 to the workpiece G while being transmitted.

The state of transmission of the pressing force on the tip side of the second mold 3 at this time is shown in FIG.
The pressing force F0 applied to the first pressing member 41 is transmitted from the second pressing member 42 to the first elastic member 5 as the pressing force F1.
The pressing force F1 presses the first mold 2, but the first mold 2 is in contact with the surface E of the second mold 3 at the surface D, so the pressing force F1 is the first mold 2. Is transmitted to the second mold 3 as a pressing force F3.

  The pressing force F3 causes the second elastic member 7 to contract, but the end of the second elastic member 7 (the end opposite to the side fixed to the second mold 3) is applied to the support member 6. Since the support member 6 is fixed and does not move, the second elastic member 7 pushes back the second mold 3 with a pressing force F4 which is a restoring force as a reaction of the pressing force F3.

In addition, the pressing force F0 applied to the first pressing member 41 is also transmitted to the pressing pin 1 in the distal direction, and is transmitted as the pressing force F2.
This pressing force F2 is a direct force that presses the rear end portion of the molding target G and causes plastic deformation of the leading end portion of the molding target G.

As described above, according to the molding apparatus S according to the present embodiment, the pressing force F1 that presses the rear end portion of the molding object G, and the tip side of the molding object G is pressed to the side opposite to the pressing force F1 ( With the pressing force F4 (which presses the workpiece G toward the rear end side), a sufficient pressing force can be secured even at the front end portion of the molding G where the transmission of the pressing force is insufficient in the conventional apparatus.
Therefore, the pressure inside the first mold 2 and the second mold 3 is equalized only by pressing from one side without requiring complicated equipment that presses from both ends of the molding G. It is possible to secure a sufficient pressing force on the other end side and reliably process the tip of the molding G.

FIG. 5 shows the pressure distribution.
FIG. 5A shows the ratio of effective pressure applied at each point in a conventional molding apparatus, about 50% at point A ′, about 30% at point B ′, about 15% at point C ′, The point D ′ was about 5%, and the pressure at the plastic deformation portion (tip portion) was insufficient, so that the plastic deformation of the tip portion could not be reliably performed.

FIG. 5B shows the ratio of effective pressure applied at each point in the molding apparatus S according to this embodiment. The point A is about 30%, the point B is about 20%, and the point C is about 20%. The point D is about 30%, and a sufficient pressing force can be applied to the plastic deformation portion (tip portion).
For this reason, the plastic deformation of the tip portion can be performed reliably.
That is, in the conventional molding apparatus, the pressing force gradually decreases as it goes to the plastic deformation side (tip end side), but in the molding apparatus S according to the present embodiment, the pressing force is efficiently applied. Can do.
In addition, it is possible to perform pressure adjustment (about 50% to 70%) with emphasis on the plastic deformation side (tip end side).

Next, referring to FIG. 6, a process of forming a worm in the small diameter portion (hereinafter referred to as “small diameter portion G1”) of the molded object G with the step portion molded as described above will be described.
In FIGS. 6 and 7, the worm portion W is shown slightly larger for explanation.
The worm portion W is molded by rolling a small diameter portion of the workpiece G with a stepped portion.
This rolling process is carried out by plastically deforming a part to be molded by a rolling die 8 in which a spiral recess that matches the shape of the worm part W is formed.

  In the present embodiment, the small diameter of the workpiece G is formed on cylindrical rolling dies 8, 8 (a recess that matches the shape of the worm portion W is formed on the outer peripheral surface) formed as a pair. By rotating these rolling dies 8 and 8 with the portion G1 sandwiched therebetween, the surface of the small diameter portion G1 is plastically deformed to form the shape of the worm portion W.

Note that the shape and number of the rolling dies 8, 8 are not limited to this, and any number of rolling dies may be used as long as they do not depart from the spirit of the present invention.
For example, a plurality of plate-shaped flat dies are used as the rolling dies 8 and the small-diameter portion G1 is sandwiched between these flat dies (a concave portion that aligns with the worm portion W is formed on the opposing surfaces on the sandwiching side). However, by moving these flat dies, the surface of the small diameter portion G1 may be plastically deformed to shape the shape of the worm portion G1.

FIG. 7 shows the armature shaft N thus molded.
As described above, according to the present embodiment, the armature shaft N in which the worm portion W is molded is formed with high accuracy and efficiency on the small diameter portion of the stepped shaft having the large diameter portion and the small diameter portion G1. be able to.

As described above, according to the processing by the molding apparatus S according to the present embodiment, it is possible to ensure the processing pressure at the tip portion of the molding target G that is a long-axis object, and a high-strength component by plastic processing. Can be provided.
In addition, as described above, the tip of the workpiece G, which is a long-axis object, can be drawn, so that high-speed machining improves productivity and stabilizes the quality of the tip by stabilizing the accuracy of the tip. Can do.
In addition, since secondary processing steps such as knurling and cutting are not required, manufacturing costs can be reduced, and shape changes and volume fluctuations can be flexibly handled, reducing capital investment. can do.
As described above, the manufacturing cost can be greatly reduced, and the molding G and the armature shaft N with high quality and low cost can be provided.

It is explanatory drawing which shows the shaping | molding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the action | operation of the shaping | molding apparatus which concerns on one Embodiment of this invention. It is detail drawing which shows the action | operation of the shaping | molding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the pressing principle of the shaping | molding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the pressure distribution of the shaping | molding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the rolling process which concerns on one Embodiment of this invention. It is explanatory drawing of the armature shaft which concerns on one Embodiment of this invention. It is explanatory drawing which shows a prior art example.

Explanation of symbols

1. Pressure pin,
2... First mold 21. First molding hole 22. First mold side first elastic member fixing portion
3. Second type,
31 ... second molding hole, 31a ... long shaft part, 31b ... taper part, 31c ... tip part,
32 ... the second mold side second elastic member fixing portion,
4 ... pressing member, 41 ... first pressing member, 42 ... second pressing member,
42a ... 2nd pressing member side 1st elastic member fixing | fixed part,
5. First elastic member,
6... Support member, 61... Support member side second elastic member fixing portion,
7. Second elastic member,
8 Rolling dies,
D, E ... face, G ... molding object, G1 ... small diameter part, N ... armature shaft,
K1 Punch case, K2 Die case, S Molding device, W Worm part

Claims (4)

A method for producing a stepped shaft having a large diameter portion and a small diameter portion,
The stepped shaft molding device is:
A first mold which is supported by a guide and is movable in the axial direction, and a first molding hole in which a pressure pin can slide is formed in the inner axial direction;
A taper-shaped taper portion that is disposed to face one end surface in the axial direction of the first mold and connects the large-diameter portion and the small-diameter portion, and the large-diameter portion and the small-diameter portion inside. A second mold in which a second molding hole configured as a matching gap is formed in the axial direction, and
A first elastic member that transmits an elastic force in the axial direction is disposed on the other axial end surface of the first mold, and the side of the second mold that does not face the first mold One end is fixed to the axial end surface of the second end, and the other end of the second elastic member that transmits the elastic force in the axial direction is disposed.
The first mold and the second mold are opposed to each other with a predetermined gap, the first molding hole and the second molding hole are disposed at a position where they communicate with each other, and The small diameter portion of the second molding hole is disposed on the second elastic member side,
A first step of inserting a rod-shaped member into the second molding hole;
The first elastic member is pressed against the first mold side to be contracted, and the pressure pin is moved in the axial direction on the side where the second mold is disposed in the first molding hole. A second step of sliding toward the end direction;
A third step of bringing the first mold into contact with the second mold by the pressing force of the first elastic member;
The first elastic member is further contracted to bring the first mold into pressure contact with the second mold, and the pressing force applied from the first elastic member to the second mold is transmitted to the first mold. The second elastic member acts to push back the second mold in the direction in which the first mold is disposed by a restoring force against the pressing force transmitted from the second mold, and the pressure pin An end portion is pressed against the molding object and the molding object is pressed toward the small-diameter portion, and the taper portion and the taper are formed on the distal end portion of the molding object by the restoring force and the pressing force of the pressure pin. And a fourth step of forming a shape that matches the small-diameter portion. The other end of the first elastic member connected to the first mold is fixed to a pressing member to which a pressing force is applied from the outside, and the first elastic member of the pressing member is The pressure pin is disposed on the connected surface,
2. The stage according to claim 1, wherein in the second step to the third step, a pressing force is applied to the first elastic member and the pressure pin through the pressing member. Manufacturing method of shaft with part. A method for manufacturing an armature shaft in which a worm is formed on the small diameter portion of the stepped shaft having a large diameter portion and a small diameter portion,
The stepped shaft molding device is:
A first mold which is supported by a guide and is movable in the axial direction, and a first molding hole in which a pressure pin can slide is formed in the inner axial direction;
A taper-shaped taper portion that is disposed to face one end surface in the axial direction of the first mold and connects the large-diameter portion and the small-diameter portion, and the large-diameter portion and the small-diameter portion inside. A second mold in which a second molding hole configured as a matching gap is formed in the axial direction, and
A first elastic member that transmits an elastic force in the axial direction is disposed on the other axial end surface of the first mold, and the side of the second mold that does not face the first mold One end is fixed to the axial end surface of the second end, and the other end of the second elastic member that transmits the elastic force in the axial direction is disposed.
The first mold and the second mold are opposed to each other with a predetermined gap, the first molding hole and the second molding hole are disposed at a position where they communicate with each other, and The small diameter portion of the second molding hole is disposed on the second elastic member side,
A first step of inserting a rod-shaped member into the second molding hole;
The first elastic member is pressed against the first mold side to be contracted, and the pressure pin is moved in the axial direction on the side where the second mold is disposed in the first molding hole. A second step of sliding toward the end direction;
A third step of bringing the first mold into contact with the second mold by the pressing force of the first elastic member;
The first elastic member is further contracted to bring the first mold into pressure contact with the second mold, and the pressing force applied from the first elastic member to the second mold is transmitted to the first mold. The second elastic member acts to push back the second mold in the direction in which the first mold is disposed by a restoring force against the pressing force transmitted from the second mold, and the pressure pin An end portion is pressed against the molding object and the molding object is pressed toward the small-diameter portion, and the taper portion and the taper are formed on the distal end portion of the molding object by the restoring force and the pressing force of the pressure pin. A fourth step of forming a shape that matches the small diameter portion;
A fifth step of forming a worm in the small-diameter portion by a rolling device equipped with a rolling die;
A method of manufacturing an armature shaft, comprising: A molding device for a stepped shaft having a large diameter portion and a small diameter portion,
The stepped shaft molding device is:
A pressure pin for pressing the rod-shaped object,
A first mold supported by a guide and movable in the axial direction, wherein a first molding hole in which the pressure pin can slide is formed in the inner axial direction;
A tapered portion that is disposed to face one axial end surface of the first mold and connects the large-diameter portion and the small-diameter portion, and the large-diameter portion and the small-diameter portion inside. A second mold in which a second molding hole configured as a matching gap is formed in the axial direction;
A first elastic member disposed on the other axial end surface of the first mold and transmitting an elastic force in the axial direction;
A second elastic member having one end fixed and an other end disposed on an end surface of the second mold not facing the first mold, and transmitting an elastic force in an axial direction; It is configured with
The first elastic member is further contracted to bring the first mold into pressure contact with the second mold, and the pressing force applied from the first elastic member to the second mold is transmitted to the first mold. The second elastic member acts to push back the second mold in the direction in which the first mold is disposed by a restoring force against the pressing force transmitted from the second mold, and the pressure pin An end portion is pressed against the molding object inserted into the second molding hole to press the molding object toward the small-diameter portion, and the molding object is pressed by the restoring force and the pressing force of the pressure pin. A molding device for a stepped shaft, wherein a shape matching the tapered portion and the small-diameter portion is formed at a tip portion of a molded product.

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