WO2021193211A1

WO2021193211A1 - Method and apparatus for manufacturing arc spring

Info

Publication number: WO2021193211A1
Application number: PCT/JP2021/010461
Authority: WO
Inventors: 昌昭前田; 高橋　秀志
Original assignee: 日本発條株式会社
Priority date: 2020-03-25
Filing date: 2021-03-15
Publication date: 2021-09-30
Also published as: JP6975873B1; CN115315323A; JPWO2021193211A1; CN115315323B

Abstract

Provided is a method for manufacturing an arc spring whereby the formation of twists in an arc spring after blasting can be inhibited. In this manufacturing method, wedges 21 are sequentially driven into spiral-shaped gaps 9a in a semi-finished product 5A of an arc spring 1 before a wire X thereof has been curved, at least one of the driving positions at which the wedges 21 have been sequentially driven in is shifted in the circumferential direction to increase the twist, in the arc spring 1, produced by the driving in of the wedges 21 when the semi-finished product 5A is curved to shape the arc spring 1, and the arc spring 1 is blasted to impart a twist in the opposite direction, with respect the twist in the arc spring 1, to cancel out the twist.

Description

Arc spring manufacturing method and equipment

The present invention relates to a method and an apparatus for manufacturing an arc spring in which the axis of the coil spring is curved.

As a conventional method for manufacturing an arc spring, there is a method in which a wedge portion is sequentially driven between spiral lines to bend the axis of a semi-finished arc spring before the axis is curved.

In such an arc spring manufacturing method, if the cuneus is driven between the lines in sequence while simply shifting the semi-finished product in the axial direction, the semi-finished product will be twisted according to the spiral shape each time the wedge is driven.

For this reason, conventionally, as in Patent Document 1, by gradually shifting the driving position of the wedge portion in the circumferential direction, the twist caused by the immediately preceding driving is offset by the twist generated by the immediately following driving.

According to this manufacturing method, it is possible to obtain a coil spring having a curved axis while suppressing twisting.

However, the arc spring may be subjected to injection processing such as shot peening after that. In this case, even if the twist is suppressed when the wedge portion is driven, the twist is generated after the injection process.

Japanese Patent No. 6538486

The problem to be solved is that the arc spring was twisted after the injection process.

The present invention provides a method and an apparatus for manufacturing an arc spring capable of suppressing twisting of the arc spring after injection processing.

The method of manufacturing an arc spring is a method of manufacturing an arc spring in which the axis of a coil spring in which a wire is spirally wound is curved. In this manufacturing method, a cuneus is sequentially driven between the spiral lines of a semi-finished product of the arc spring before the axis is curved, and at least one of the driving positions where the cuneus is sequentially driven is rotated. By shifting in the direction and bending the axis of the semi-finished product to increase or decrease the twist generated in the arc spring by driving the cuneus when forming the arc spring, the arc spring is injected. A twist in the opposite direction to the twist of the arc spring is applied to cancel the twist.

The arc spring manufacturing device is an arc spring manufacturing device in which the axis of the coil spring in which the wire is spirally wound is curved. In this manufacturing apparatus, a cuneus is sequentially driven between the spiral lines with respect to the semi-finished product of the arc spring before the axis is curved, and at least one of the driving positions where the cuneus is sequentially driven is rotated. When the semi-finished product is displaced in the direction and the axis of the semi-finished product is curved to form the arc spring, the driving portion for increasing or decreasing the twist generated in the arc spring due to the driving of the wedge portion and the arc spring are injected. As a result, it is provided with an injection processing unit that imparts a twist in the opposite direction to the twist of the arc spring and cancels the twist.

In the present invention, since the twist can be canceled by performing the injection processing, it is possible to suppress the occurrence of the twist in the arc spring after the injection processing.

1 (A) is a side view showing an arc spring according to an embodiment of the present invention, FIG. 1 (B) is a side view showing a semi-finished product of an S-winding arc spring, and FIG. 1 (C) is a Z-winding arc spring. It is a side view which shows the semi-finished product of. FIG. 2 is a block diagram showing an arc spring manufacturing apparatus according to an embodiment together with a twisted state of the arc spring. 3 (A) and 3 (B) are partially omitted side views showing a driving portion of the arc spring manufacturing apparatus according to the embodiment, FIG. 3 (A) is the initial driving stage, and FIG. 3 (B) is the driving stage. It is in the state of. 4 (A) and 4 (B) are plan views of semi-finished products showing the driving position and the twisting direction of the wedge portion according to the embodiment, FIG. 4 (A) is winding S, and FIG. 4 (B) is Z. It is a volume. FIG. 5 is a graph showing the amount of twist in each step in comparison between Examples and Comparative Examples. FIG. 6 is a schematic view of an arc spring showing a method of measuring the twist amount of FIG.

The purpose of suppressing the occurrence of twisting in the arc spring after injection processing was realized by causing twisting that is offset by injection processing by driving the wedge part when molding the arc spring.

The method for manufacturing the arc spring (1) of the present invention is to manufacture the arc spring (1) by bending the axis (X) of the coil spring in which the wire rod (3) is spirally wound. In this manufacturing method, the wedge portion (21) is driven and the injection process is performed on the semi-finished products (5A, 5B) of the arc spring (1).

To drive the wedge portion (21), the wedge portion (21) is sequentially driven between the spiral lines (9a) with respect to the semi-finished products (5A, 5B) of the arc spring (1) before the axis (X) is curved. .. When at least one of the driving positions where these wedge portions (21) are sequentially driven is shifted in the circumferential direction and the axis (X) of the semi-finished products (5A, 5B) is curved to form the arc spring (1). The twist of the arc spring (1) caused by the driving of the wedge portion (21) is increased or decreased.

The injection process cancels the twist by imparting a twist in the opposite direction to the twist of the arc spring (1). The direction of twisting due to injection processing is set according to the direction of the coiled winding of the arc spring (1). The offsetting of the twist may not only completely eliminate the twist, but may also leave the twist within a predetermined allowable range remaining.

The increase or decrease of the twist of the arc spring (1) sets the twist that is offset by the reverse twist due to the injection process, and is performed according to the reverse twist. The increase or decrease of the twist of the arc spring (1) can be set by the direction in which the driving position is shifted, the amount of the shift, and the number of shifts.

The driving position can be shifted by relative rotation between the semi-finished products (5A, 5B) and the wedge portion (21).

The driving position may be gradually shifted in the circumferential direction. In this case, the amount of shift of the driving position may be the same.

The molded arc spring (1) may be heat-treated before the injection process. The heat treatment imparts a twist in the opposite direction to the twist of the arc spring (1) to partially cancel the twist. In this case, the injection process imparts a reverse twist to the remaining twist after the partial offset.

The injection process may be shot peening performed from the radial outside of the arc spring (1). In this case, the compressive residual stress on the outer circumference is made larger than the inner circumference of the arc spring (1).

The arc spring (1) manufacturing apparatus (13) includes a driving portion (15) and an injection processing portion (19). The driving portion (15) sequentially drives the wedge portion (21) between the spiral lines (9a) with respect to the semi-finished products (5A, 5B) of the arc spring (1) before the axis (X) is curved. In the driving portion (15), at least one of the driving positions in which these wedge portions (21) are sequentially driven is shifted in the circumferential direction, and the axis (X) of the semi-finished products (5A, 5B) is curved to form an arc spring. While forming (1), the twist of the arc spring (1) caused by the driving of the wedge portion (21) is increased or decreased. The injection processing unit (19) performs injection processing on the arc spring (1) to impart a twist in the opposite direction to the twist of the arc spring (1) and cancel the twist.

[Arc spring]
1 (A) to 1 (C) are a side view showing an arc spring, a side view showing a semi-finished product of an S-winding arc spring, and a side view showing a semi-finished product of a Z-winding arc spring, respectively.

The arc spring 1 of this embodiment is an arc-shaped coil spring in which the wire rod 3 is spirally wound and the axis X is curved. The semi-finished product 5A is in a state before the axis X is curved, and is in a straight shape in this embodiment. The arc spring 1 and the semi-finished product 5A have a so-called S winding (left winding), and are wound counterclockwise around the axis X when viewed from the

ends

7a and 7b.

The winding direction may be reversed as in the semi-finished product 5B. The semi-finished product 5B is a so-called Z winding (right winding), and is wound clockwise around the axis X when viewed from the

ends

7a and 7b. The arc spring (not shown) formed from this semi-finished product 5B is also Z-wound.

Note that the

semi-finished products

5A and 5B mean those before the axis X is curved, and do not have to be straight. Therefore, the

semi-finished products

5A and 5B also include those in which the axis X is curved or bent with respect to the straight shape in the manufacturing process.

The arc spring 1 of this embodiment has a main body portion 9 and endwind

portions

11a and 11b on both sides. The main body 9 is formed with a relatively large distance (hereinafter referred to as “pitch”) in the direction along the axis X of the spiral line 9a (gap between adjacent coil portions 9b), and is a countersunk portion. The pitches of 11a and 11b are relatively small. Seat surfaces 12a and 12b formed by cutting on both end surfaces of the arc spring 1 are formed on the

end winding portions

11a and 11b. The

end winding portions

11a and 11b can be omitted.

In the following, the direction along the curved axis X is referred to as "axial direction", and the direction along the curved axis X before bending is referred to as "curved front axial direction".

The semi-finished product 5A has the same configuration as the arc spring 1 except that the axis X is straight. Further, the semi-finished product 5B has the same configuration as the arc spring 1 except that the axis X is straight and the winding direction is different.

[Arc spring manufacturing equipment]
FIG. 2 is a block diagram showing an arc spring manufacturing apparatus together with a twisted state of the arc spring. 3 (A) and 3 (B) are partially omitted side views showing a driving portion of the arc spring manufacturing apparatus, FIG. 3 (A) is a state at the initial stage of driving, and FIG. 3 (B) is a state at the late stage of driving. ..

The manufacturing apparatus 13 of the arc spring 1 of this embodiment (hereinafter, simply referred to as “manufacturing apparatus 13”) includes a driving unit 15, a heat treatment unit 17, and an injection processing unit 19.

The driving portion 15 sequentially drives the wedge portion 21 into the spiral line spacing 9a of the semi-finished product 5A before the axis X is curved. In this embodiment, the driving position of the wedge portion 21 is gradually shifted in the circumferential direction (see FIG. 4). By this driving, the semi-finished product 5A is curved to form the arc spring 1, and the twist of the arc spring 1 caused by the driving of the wedge portion 21 is increased. The circumferential direction refers to the circumferential direction around the axis X of the semi-finished product 5A.

The driving portion 15 of this embodiment includes a pair of

grip portions

23a and 23b and a wedge portion 21. The pair of

gripping portions

23a and 23b are composed of gripping mechanisms such as an air chuck, and can rotate around the axis X and move in the curved front axial direction, respectively. As a result, each time the wedge portion 21 is driven, the

grip portions

23a and 23b rotate the semi-finished product 5A by a predetermined angle around the axis X and move the semi-finished product 5A by a predetermined amount in the curved front axis direction. The rotation around the axis X and the movement in the curved front axis direction may be relative to the wedge portion 21. Therefore, it is also possible to rotate the wedge portion 21 and move it in the curved front axis direction.

The

gripping portions

23a and 23b may be rotated or moved in the curved front axis direction by an appropriate driving portion. For example, the rotation of the

grip portions

23a and 23b can be performed by a servomotor. Further, the

grip portions

23a and 23b can be moved in the curved front axis direction by a servomotor and a ball screw.

One grip 23a grips one end 7a of the semi-finished product 5A, and the other grip 23b grips the other end 7b of the semi-finished product 5A. The grip by one grip portion 23a is performed from the beginning of driving the wedge portion 21, and the grip by the other grip portion 23b is performed by the one grip portion 23a while the wedge portion 21 is being sequentially driven into the semi-finished product 5A. It is performed by switching from gripping.

The wedge portion 21 is an expansion tool having a wedge-shaped tip. The wedge portion 21 is driven in synchronization with the movement and rotation of the semi-finished product 5A so that the wedge portion 21 is driven into the line interval 9a of the semi-finished product 5A. At the time of this driving, the semi-finished product 5A is supported by the die 25 facing the wedge portion 21 in the driving direction (vertical direction in the embodiment).

The wedge portion 21 may be driven by an appropriate drive unit, but for example, the rotational operation of the servomotor can be converted into an operation in the driving direction by a cam and transmitted to the wedge portion 21.

The arc spring 1 formed by driving the wedge portion 21 is conveyed to the heat treatment portion 17 by a conveying means (not shown).

The heat treatment unit 17 performs annealing as a heat treatment on the arc spring 1 before the injection process. The heat treatment unit 17 can be configured by a well-known electric furnace or the like. Therefore, the details of the heat treatment unit 17 will be omitted.

The heat treatment in the heat treatment section 17 imparts a twist in the opposite direction to the twist of the arc spring 1 due to the driving of the wedge portion 21, and partially cancels the twist of the arc spring 1.

The injection processing unit 19 performs shot peening from the radial outside of the arc spring 1 as injection processing. The injection processing unit 19 can be configured by a well-known shot peening device. Therefore, the details of the injection processing unit 19 will be omitted.

By the injection processing in the injection processing unit 19, the twist of the arc spring 1 due to the driving of the wedge portion 21 is offset by giving a twist in the opposite direction. In this embodiment, a reverse twist is applied to the remaining twist after being partially offset by the heat treatment.

Note that each part of the manufacturing apparatus 13 may be controlled by a computer (not shown).

[Manufacturing method of arc spring]
In the method of manufacturing the arc spring 1 of this embodiment, a case where the arc spring 1 is manufactured from a semi-finished product 5A having an effective number of turns of 49 and an outer diameter of 15.25 mm will be described. However, it is also possible to manufacture the arc spring 1 from the semi-finished product 5A having other dimensions by applying the manufacturing method of this embodiment.

In such a manufacturing method, the arc spring 1 is first formed by driving the wedge portion 21 into the semi-finished product 5A.

At the time of driving, the semi-finished product 5A is conveyed to the driving portion 15 by a conveying means (not shown), and as shown in FIG. 3A, one end portion 7a of the semi-finished product 5A is gripped by one grip portion 23a and the other end. The portion 7b is positioned on the die 25.

Then, as shown in FIG. 3B, while rotating the semi-finished product 5A around the axis X and moving it in the curved front axis direction, the wedge portion is formed from the other end 7b side of the semi-finished product 5A to the spiral line interval 9a. Type 21 in sequence. As a result, the semi-finished product 5A is plastically deformed so as to bend the axis X, and the arc spring 1 is formed. In this embodiment, the wedge portion 21 is driven 49 times.

At this time, the arc spring 1 is twisted by driving the wedge portion 21, and the twist is increased or decreased by the rotation of the semi-finished product 5A.

4 (A) and 4 (B) are plan views of semi-finished products showing the driving position of the wedge portion and the direction of twisting, FIG. 4 (A) is winding S, and FIG. 4 (B) is winding Z.

In the case of the S-wound semi-finished product 5A, the arc spring 1 is twisted in the S direction due to the driving of the wedge portion 21. The S direction refers to a direction in which the other end portion 7b of the arc spring 1 or the semi-finished product 5A is rotated counterclockwise when viewed from the axial direction. The Z direction is a direction opposite to the S direction, and refers to a direction in which the other end portion 7b of the arc spring 1 or the semi-finished product 5A is rotated clockwise when viewed from the axial direction. When the other end 7b of the twisted arc spring 1 is viewed from the axial direction due to the twist in the S direction, the twist is centered on the axis X of the non-twisted arc spring 1 (see FIG. 1 (A)). The axis Xt (see FIG. 6) of a certain arc spring 1 is deformed in a clockwise spiral. The opposite is true for the Z-volume semi-finished product 5B.

When increasing the twist in the S winding, the twist in the S direction is added by rotating the semi-finished product 5A in the S direction by a predetermined angle each time the wedge portion 21 is driven. Therefore, in this embodiment, the driving position is gradually shifted, and the amount of shifting of the driving position at this time is the same. On the contrary, when reducing the twist, the semi-finished product 5A is rotated in the Z direction by a predetermined angle each time the wedge portion 21 is driven, thereby adding the twist in the Z direction and partially canceling the twist in the S direction. .. In the case of volume Z, the opposite is true for volume S.

The arc spring 1 of this embodiment increases the twist in the S direction in the S winding in response to the twist in the heat treatment and the injection process described later. Therefore, each time the wedge portion 21 is driven, the semi-finished product 5A is rotated in the S direction by a predetermined angle. The rotation of the semi-finished product 5A may be performed by rotating the

grip portion

23a or 23b in the Z direction, which is the opposite direction to the initial position, and returning the

grip portion

23a or 23b to the initial position. The driving position of the wedge portion 21 due to rotation is gradually shifted in the Z direction from the other end portion 7b to the one end portion 7a. The virtual line L1 connecting the driving positions of the wedge portions 21 is as shown in FIG. The virtual line L2 in the case of the Z winding is the opposite of that in the case of the S winding.

Due to such a shift in the driving position, in this embodiment, the semi-finished product 5A is rotated by 0.489 degrees each time the wedge portion 21 is driven in the twist of 8.5 degrees in the S direction when the semi-finished product 5A is not rotated. A twist of 24 degrees in the S direction is added by driving 49 times. Therefore, the twist in the S direction generated in the molded arc spring 1 is 32.5 degrees.

Here, the angle indicates the amount of twist and corresponds to the angle obtained by rotating the other end 7b of the semi-finished product 5A in the circumferential direction with respect to the initial position. Further, the angle is positive in the S direction and negative in the Z direction.

The arc spring 1 thus formed is annealed as a heat treatment. That is, the arc spring 1 is conveyed from the driving unit 15 to the heat treatment unit 17 by a transfer means (not shown), and the heat treatment unit 17 performs appropriate annealing.

At the time of annealing, a twist in the opposite direction to the twist of the arc spring 1 due to the driving of the wedge portion 21 is given, and the twist of the arc spring 1 is partially offset.

In the case of winding S, the arc spring 1 is twisted in the Z direction due to annealing. Therefore, the twist in the S direction generated in the arc spring 1 is partially offset. The case of volume Z is the opposite of that of volume S.

After annealing, the arc spring 1 is subjected to shot peening as an injection process. That is, the arc spring 1 is conveyed from the heat treatment unit 17 to the injection processing unit 19 by a transfer means (not shown), and the injection processing unit 19 performs appropriate shot peening.

By shot peening in the injection processing unit 19, the twist of the arc spring 1 remaining partially offset by the heat treatment is offset by giving a twist in the opposite direction.

In the case of winding S, the compressive residual stress on the outer circumference becomes larger than that on the inner circumference of the arc spring 1 due to the difference in the amount of collision of the shot particles on the inner circumference and the outer circumference of the arc spring 1, and twisting due to shot peening occurs in the Z direction. .. The amount of twist can be set by the compressive residual stress on the inner circumference and the outer circumference. In the case of volume Z, the opposite is true for volume S.

The twist in the Z direction due to shot peening in this embodiment is -32.5 degrees when combined with the twist due to annealing. Therefore, in this embodiment, after the shot peening is completed, the twist of the arc spring 1 is removed, and a flat arc spring 1 without twist can be obtained. The amount of twist due to annealing is significantly smaller than the amount of twist due to shot peening. Therefore, the amount of twist due to annealing can be ignored.

Note that annealing may be performed as a heat treatment even after shot peening. This annealing offsets the twist that remains after shot peening. However, as with the annealing before shot peening, the amount of twist due to annealing after shot peening is significantly smaller than the amount of twist due to shot peening, and can be ignored. In this case, only one of the twist amounts due to annealing before and after shot peening may be ignored.

The relationship of angles related to the offsetting of the above-mentioned twist can be expressed by the following equation. The closer θ is to zero, the higher the flatness of the arc spring 1. The angle has a directional property in the circumferential direction, and when the angle in one circumferential direction is positive, the angle in the other circumferential direction is negative.

Θ = α + β × N + γ

Here, α is the angle of twist that occurs when the wedge portion 21 is driven without rotating the semi-finished product 5A, β is the angle at which the semi-finished product 5A is rotated each time the wedge portion 21 is driven, and N is the wedge portion. The number of times 21 is driven and γ are the total values of the twist angles generated in the process after the wedge portion 21 is driven.

FIG. 5 is a graph showing the amount of twist in each step in comparison between the examples and the comparative examples. FIG. 6 is a schematic view of an arc spring showing a method of measuring the twist amount of FIG.

In FIG. 5, an example shows an arc spring 1 manufactured by the manufacturing method of the above embodiment. In the comparative example, the same semi-finished product 5A as in the example was used, the twist of the arc spring was removed when the wedge portion was driven, and then annealing and shot peening were performed. That is, in the comparative example, the twist in the Z direction of −8.5 degrees is added by rotating the semi-finished product, and the twist in the S direction of 8.5 degrees due to the driving of the wedge portion is offset.

In FIG. 5, the height H represents the amount of twist of the arc spring 1 on a scale different from the angle, and the arc spring 1 with respect to the surface F in a state where the arc spring 1 is placed on the flat surface F. Shows the height of the top of the. This height H is measured after each step on the left end, and the corresponding twist angle is shown on the right end. The value of the height H means that the flatness of the arc spring 1 increases as the outer diameter of the semi-finished product 5A approaches 15.25 mm. This is shown as (height H-outer diameter) in FIG. The angles at the right end are added up after heat treatment and injection processing.

In the embodiment, the twist in the S direction of 32.5 degrees occurs after the arc spring 1 is formed, whereas in the comparative example, the twist is offset. Therefore, the value of (height H-outer diameter) is significantly smaller in the comparative example than in the example.

However, when the shot peening is completed through annealing, the twist in the S direction is offset by the twist in the Z direction in the embodiment. On the other hand, in the comparative example, a twist of -32.5 degrees in the Z direction occurs. Therefore, the value of (height H-outer diameter) is significantly larger in the comparative example than in the example.

[Effect of Examples]
As described above, in the method of manufacturing the arc spring 1 of the present embodiment, the wedge portion 21 is sequentially driven into the spiral line interval 9a with respect to the semi-finished product 5A of the arc spring 1 before the axis X is curved, and the wedge portion is formed. At least one of the driving positions in which 21 is sequentially driven is shifted in the circumferential direction to increase the twist of the arc spring 1 caused by the driving of the wedge portion 21 when the semi-finished product 5A is curved to form the arc spring 1. By performing injection processing on the arc spring 1, a twist in the opposite direction to the twist of the arc spring 1 is imparted to cancel the twist.

Therefore, in this embodiment, the twist can be controlled when the wedge portion 21 is driven, and the controlled twist can be offset by the reverse twist during the injection process. Therefore, it is possible to reliably suppress the occurrence of twisting in the arc spring 1 after the injection process.

In this embodiment, the arc spring 1 is heat-treated before the injection process to partially cancel the twist of the arc spring 1 by the reverse twist, and after the twist is partially offset by the injection process. Gives a reverse twist to the remaining twist.

Therefore, in this embodiment, even if the heat treatment is performed before the injection processing, it is possible to reliably suppress the occurrence of twisting in the arc spring 1 after the injection processing.

The injection process is shot peening performed from the radial outside of the arc spring 1, and the compressive residual stress on the outer circumference is larger than that on the inner circumference of the arc spring 1.

Thereby, in the present embodiment, the twisting in the direction opposite to the twisting caused by the driving of the wedge portion 21 can be reliably imparted by the injection processing, and the twisting of the arc spring 1 after the injection processing can be more reliably suppressed.

Further, in this embodiment, when the wedge portions 21 are sequentially driven, the driving position is gradually shifted, and the shifting amount of the driving position at this time is the same. Therefore, the twist of the arc spring 1 can be easily and surely increased.

The manufacturing apparatus 13 sequentially drives the cuneus 21 into the spiral interline 9a with respect to the semi-finished product 5A of the arc spring 1 before bending the axis X, and at least one of the driving positions where the cuneus 21 is sequentially driven. Is shifted in the circumferential direction, and when the semi-finished product 5A is curved to form the arc spring 1, the driving portion 15 for increasing the twist of the arc spring 1 caused by the driving of the wedge portion 21 and the arc spring 1 are injected. As a result, the injection processing unit 19 is provided so as to impart a twist in the opposite direction to the twist of the arc spring 1 and cancel the twist of the arc spring 1.

Therefore, the manufacturing apparatus 13 can surely suppress the occurrence of twisting of the arc spring 1 after the injection processing, as in the above manufacturing method.

1 Arc spring 3

Wire

5A, 5B Semi-finished product 9a Line-to-line 13 Manufacturing equipment 15 Driving part 17 Heat treatment part 19 Injection processing part 21 Wedge part

Claims

A method for manufacturing an arc spring in which the axis of a coil spring in which a wire is spirally wound is curved.
A wedge portion is sequentially driven between the spiral lines of the semi-finished product of the arc spring before the axis is curved, and at least one of the driving positions where the wedge portion is sequentially driven is shifted in the circumferential direction. When the axis of the semi-finished product is curved to form the arc spring, the twist generated in the arc spring due to the driving of the wedge portion is increased or decreased.
By performing injection processing on the arc spring, a twist in the opposite direction to the twist of the arc spring is imparted to cancel the twist.
How to manufacture an arc spring.
The method for manufacturing an arc spring according to claim 1.
By heat-treating the arc spring before the injection process, a twist in the opposite direction to the twist of the arc spring is imparted to partially cancel the twist.
The injection process imparts a reverse twist to the remaining twist after the partial offset.
How to manufacture an arc spring.
The method for manufacturing an arc spring according to claim 1 or 2.
The injection process is shot peening performed from the radial outside of the arc spring, and the compressive residual stress on the outer circumference is made larger than the inner circumference of the semi-finished product.
How to manufacture an arc spring.
The method for manufacturing an arc spring according to any one of claims 1 to 3.
The driving position is gradually shifted in the circumferential direction.
How to manufacture an arc spring.
The method for manufacturing an arc spring according to claim 4.
The amount of shift of the driving position that is gradually shifted in the circumferential direction is the same.
How to manufacture an arc spring.
This is an arc spring manufacturing device in which the axis of a coil spring in which a wire is spirally wound is curved.
A wedge portion is sequentially driven between the spiral lines of the semi-finished product of the arc spring before the axis is curved, and at least one of the driving positions where the wedge portion is sequentially driven is shifted in the circumferential direction. A driving portion that increases or decreases the twist generated in the arc spring by driving the wedge portion when the axis of the semi-finished product is curved to form the arc spring, and a driving portion.
By performing injection processing on the arc spring, an injection processing portion that imparts a twist in the opposite direction to the twist of the arc spring and cancels the twist, and an injection processing portion.
An arc spring manufacturing device equipped with.