JPH10211539A - Manufacture of gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a gear which can work an outer tooth (slice tooth) and an inner tooth (herical spline) in the one process regardless of a helical angle and can manufacture a product having good dimensional precision without controlling the dispersion of wt. of a blank at the time of forming a chamber. SOLUTION: After arranging the blank 1A on the inner periphery of a cylinder in a die 5, an upper die is lowered and a mandrel 12 is inserted into the inner periphery of the blank 1A and the blank 1A is pressed with a knock-out pin 6 and an outer punch 13. By this method, the inner tooth 1a is preformed on the inner periphery of the blank 1A by fluidizing the blank 1A into the inner diameter direction and the chamfer forming part 6c of the knock-out pin 6 to form the chamfer 1c at the lower end surface. Thereafter, at the time of further lowering by opening the back pressure of the knock-out pin 6, the outer tooth is formed on the outer periphery of the blank 1A with the forming tooth 5b of the die 5 by extruding the blank 1A with the outer punch 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a gear having a helical spline on the inner periphery and a spur gear on the outer periphery.

[0002]

2. Description of the Related Art Conventionally, there is a method of forming a helical spline on the inner periphery of a component by cold extrusion. However, in this cold extrusion, the processing limit of the helical angle is as low as about 18 degrees, and cannot be applied to a helical angle of 18 degrees or more. In contrast, Japanese Patent Publication No. 62-4
According to the “method of machining the inner diameter of a cylindrical part” disclosed in Japanese Patent No. 5012, the machining limit of the helical angle is set to about 36.
It is possible to improve to the degree. In this processing method, a flange is provided at an axial end of a cylindrical material, and a stepped inner diameter (hole) is formed in advance on an inner diameter of the flange, and a stamping die is formed from the flange at the inner diameter of the material. The helical spline can be formed on the inner diameter surface by plastic deformation while being pressed into the (hole) and applying a tensile force to the material (cylindrical portion).

In Japanese Patent Publication No. 53-8538,
A method of forming a chamfer on the end of a spur gear is disclosed. According to this method, the material is pressed by a punch against a die having a tooth forming portion on the inner periphery to form a tooth profile (spur gear).
After forming the chamfer, the chamfer can be continuously formed on the end face of the material at the chamfer forming portion provided at the back of the die.

[0004]

However, a gear 1 having a helical spline 1a (having a helical angle of 18 degrees or more) on the inner periphery and a spur gear 1b on the outer periphery as shown in FIG.
If the processing method disclosed in Japanese Patent Publication No. 62-45012 is used, it is necessary to divide the processing step into two steps. That is, in the first step, at the same time as the formation of the external teeth (spur gear), the flange part serving as the processing reference of the internal teeth (helical spline) is formed, and in the second step, the internal teeth are formed.
For this reason, it is necessary to adjust the accuracy of the coaxiality and the like in each step, and the processing time is greatly lengthened. In addition, Japanese Patent Publication No. 53-8
When the chamfer 1c is formed by the method disclosed in Japanese Patent No. 539, since the inside of the mold is in a sealed state, if the working pressure is excessively applied due to the variation in the weight of the material, the mold may be damaged at an early stage. Therefore, in order to manufacture a product having high dimensional accuracy, equipment for inspecting the weight of the raw material immediately before the forming process and an inspection time are required, which causes a problem that the cost is greatly increased.

The present invention has been made based on the above circumstances, and has as its object to process external teeth (spur gears) and internal teeth (helical splines) in the same process regardless of the helical angle of the helical splines. SUMMARY OF THE INVENTION It is an object of the present invention to provide a gear manufacturing method capable of manufacturing a gear with high dimensional accuracy without controlling the weight variation of the material at the time of chamfer molding.

[0006]

According to the first aspect of the present invention, the material is arranged in the outer peripheral space of the helical spline molding teeth, and the material is pressed from both end surfaces while the outer peripheral surface of the material is regulated. By forming a helical spline on the inner periphery of the material and continuously extruding the material into the inner peripheral space of the spur gear forming teeth, a spur gear can be formed on the outer periphery of the material. In this case, since the steps from the formation of the helical spline to the formation of the spur gear can be performed in a continuous step (the same step), it is not necessary to adjust the accuracy in each step as in the conventional case. Further, since the helical spline is formed on the inner periphery of the material by swaging, the external teeth (spur gear) and the internal teeth (helical spline) can be processed in the same process regardless of the helical angle.

According to the second aspect of the present invention, the material is placed in the outer peripheral space of the helical spline molding teeth, and the material is held at both ends by the knockout pin and the outer punch while the outer peripheral surface of the material is regulated by the inner peripheral surface of the die. Forming a helical spline on the inner periphery of the material by pressing from the surface, and forming the spur gear on the outer periphery of the material by continuously extruding the material into the inner peripheral space of the spur gear forming teeth while pressing with the outer punch Can be. In this case, since the steps from the formation of the helical spline to the formation of the spur gear can be performed in a continuous step (the same step), it is not necessary to adjust the accuracy in each step as in the conventional case. Further, since the helical spline is formed on the inner periphery of the material by swaging, the external teeth (spur gear) and the internal teeth (helical spline) can be processed in the same process regardless of the helical angle.

According to the third aspect, after the material is pressed from both end faces by the knockout pin and the outer punch, the backpressure of the knockout pin is released by the back pressure device, so that the knockout pin can be moved. Thus, the material can be pressed by the outer punch and extruded into the inner peripheral space of the spur gear forming teeth.

According to the fourth aspect, the chamfer forming portion is provided on the end face of the knockout pin facing the one end face of the material, and the chamfer can be formed on one end face of the material at the same time as the helical spline is formed. . in this case,
Variations in the weight of the material can be absorbed by molding the helical spline (that is, the degree of helical spline molding varies according to the weight of the material), so there is no need to manage the variation in the weight of the material during chamfer molding, resulting in weight variation. However, excessive working pressure can be prevented from being applied.

[0010]

Next, a method for manufacturing a gear according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of the gear manufacturing apparatus. The gear 1 of the present embodiment is used, for example, as a pinion gear of a starter, and has a helical spline 1a (hereinafter referred to as an internal tooth 1a) on the inner periphery and a spur gear 1b on the outer periphery as shown in FIG. (Hereinafter referred to as external teeth 1b). A chamfer 1 is provided on one axial end surface of the external teeth 1b.
c is formed, and a circular flange 1d is provided on the other end side in the axial direction of the external teeth 1b. The outer diameter of the flange 1d is substantially the same as the outer diameter of the external teeth 1b.

As shown in FIG. 1, the gear manufacturing apparatus 2 is composed of a lower mold 3 and an upper mold 4 and processes (forges) a material 1A previously formed into an annular body to manufacture the gear 1 described above. Device. The lower mold 3 includes a die 5 and a knockout pin 6, and the knockout pin 6 is provided so as to be vertically movable in FIG. 1 with respect to the die 5 fixed to the lower mold 3. As shown in FIG. 2, the die 5 has a cylindrical inner peripheral surface 5a, and a plurality of forming teeth 5b (spur gear forming teeth / figure) for forming the external teeth 1b of the gear 1 on the cylindrical inner peripheral surface 5a. 3) protruding toward the center. The knockout pin 6 is shown in FIG.
As shown in FIG. 5, a plurality of teeth 6b are protruded from the outer periphery of the cylindrical portion 6a, and the teeth 6b are inserted into the inner periphery of the die 5 in a state fitted to the molding teeth 5b of the die 5. However, the outer peripheral shape of the tooth portion 6b of the knockout pin 6 is smaller than the inner peripheral shape of the molding tooth 5b of the die 5 so that the knockout pin 6 can slide on the inner periphery of the die 5 in the axial direction (vertical direction in FIG. 1). It is set slightly smaller. A chamfer forming portion 6c for forming the chamfer 1c of the gear 1 is provided at the upper end of the tooth portion 6b.

An oil reservoir 7 for storing oil is formed in the lower mold 3, and the oil reservoir 7 is connected to a back pressure device 9 through an oil passage 8. The pressure of the back pressure device 9 (back pressure) is stored in the oil reservoir 7.
Cylinder 10 that can move oil reservoir 7 up and down in accordance with
The knockout pin 6 is connected to the cylinder 10 through a connection member 11. The back pressure device 9 includes a relief valve (not shown) that allows oil in the oil reservoir 7 to flow out through the oil passage 8, and controls the back pressure of the knockout pin 6 by adjusting the valve opening pressure of the relief valve. Accordingly, the knockout pin 6 is held by receiving the back pressure set by the back pressure device 9, and can move downward from above the knockout pin 6 when a pressure higher than the back pressure is applied.

The upper mold 4 includes a mandrel 12, an outer punch 13, and a slide knockout mechanism 14, and is provided so as to be vertically slidable with respect to the lower mold 3.
The mandrel 12 has a plurality of forming teeth 12a (helical spline forming teeth / see FIG. 2) for forming the internal teeth 1a of the gear 1 on the outer periphery of the lower end portion of the cylindrical shape. However, the outer diameter of the molded teeth 12a is slightly smaller than the inner diameter of the cylindrical portion 6a of the knockout pin 6, and is set to a size that can be inserted into the inner periphery of the cylindrical portion 6a. Also, the mandrel 12
It is provided rotatable with respect to the outer punch 13. The outer punch 13 is provided in a cylindrical shape fitted to the outer periphery of the mandrel 12. However, the outer diameter of the outer punch 13 is slightly smaller than the inner diameter of the cylindrical inner peripheral surface 5a of the die 5,
The size is set such that it can be inserted into the cylindrical inner peripheral surface 5a of the die 5. The slide knockout mechanism 14 moves the outer punch 13 relative to the mandrel 12 in the axial direction.

Next, a method of manufacturing the gear 1 by the gear manufacturing apparatus 2 will be described. First, the raw material 1A is arranged on the inner periphery of the cylinder of the die 5. The material 1A forming the annular body is formed so that the inner diameter is slightly larger than the outer diameter of the molding teeth 12a of the mandrel 12, and the outer diameter of the material 1A is slightly smaller than the inner diameter of the cylindrical inner peripheral surface 5a of the die 5. Subsequently, the upper mold 4 is lowered, the mandrel 12 is inserted into the inner periphery of the material 1A, and the external teeth 1b are slightly formed while the material 1A is sandwiched between the knockout pin 6 and the outer punch 13. Push the material 1A to the position. At this position, the back pressure of the knockout pin 6 is adjusted by the back pressure device 9 so that the chamfer 1c can be formed on the end face of the material 1A.

Thereafter, the upper die 4 is further lowered to press the blank 1A with the knockout pin 6 and the outer punch 13. Since the outer peripheral surface of the pressurized material 1A is regulated by the cylindrical inner peripheral surface 5a of the die 5, the material 1A flows to the chamfer forming portion 6c of the knockout pin 6 and the inner diameter direction having a gap. As a result, as shown in FIG.
When the material 1A flows into the groove between the second molding teeth 12a,
The internal teeth 1a are preformed on the inner periphery of the raw material 1A (at this point, not yet formed into the shape of the complete internal teeth 1a), and the chamfer 1c is formed on the lower end surface of the raw material 1A.

Next, the relief valve of the back pressure device 9 is opened to release the back pressure of the knockout pin 6. This allows
Since the knockout pin 6 can move downward, the material 1A whose lower end surface has been supported by the knockout pin 6 is pushed downward by the outer punch 13 as the upper die 4 descends. As a result, the external teeth 1b having the flange 1d on the outer periphery of the material 1A are extruded by the molding teeth 5b protruding from the inner periphery of the die 5, and the material 1A also moves in the inner diameter direction when the external teeth 1b are formed. By flowing, the preformed internal teeth 1a are formed into a final shape and completed as a forged gear 1 (see FIG. 3).

After the molding of the internal teeth 1a and the external teeth 1b is completed,
The upper die 4 is raised, and the knockout pin 6 is pushed upward to discharge the gear 1 from the die 5. Further, the outer punch 13 is slid downward by the slide knockout mechanism 14 while rotating the mandrel 12. As a result, the internal teeth 1 of the gear 1 meshed at the time of molding are formed.
a is disengaged from the molding teeth 12a of the mandrel 12, and the gear 1 is discharged from the mandrel 12.

(Effect of this embodiment) According to this embodiment, the helical spline 1a is provided on the inner periphery, and the spur gear 1b is provided on the outer periphery.
Can be manufactured by a single forging process using the gear manufacturing apparatus 2, so that precision adjustment for each process as in the related art is unnecessary. Further, since the helical spline 1a is formed on the inner periphery of the material 1A by swaging, the spur gear 1b and the helical spline 1a can be processed in the same step regardless of the helical angle (even at a helical angle of 18 degrees or more).

Further, in this embodiment, the knockout pin 6
A chamfer forming portion 6c is provided on the upper end surface of the material 1A, and the chamfer 1c can be formed on the lower end surface of the material 1A at the same time as the helical spline 1a is preformed. In this case, the weight variation of the material 1A is reduced by the helical spline 1a.
(That is, the degree of molding of the helical spline 1a changes in accordance with the weight of the material 1A), so that there is no need to manage the variation in the weight of the material 1A during the molding of the chamfer 1c. In addition, excessive working pressure can be prevented from being applied. This allows
Without checking the weight of the material 1A immediately before molding,
A product (gear 1) with good dimensional accuracy can be provided. In addition, since equipment for inspecting the weight of the material 1A and the inspection time are not required, the cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gear manufacturing apparatus.

FIG. 2 is a cross-sectional view showing a gear manufacturing process.

FIG. 3 is a cross-sectional view illustrating a manufacturing process of the gear.

FIG. 4 is a perspective view of a gear.

[Explanation of symbols]

 Reference Signs List 1 gear 1A material 1a internal teeth (helical spline) 1b external teeth (spur gear) 1c chamfer 1d flange 5 die (external tooth molding member) 5a cylindrical inner peripheral surface 5b molding teeth (spur gear molding teeth) 6 knockout pin 6c chamfer Forming part 9 Back pressure device 12 Mandrel (internal tooth forming member) 12a Forming tooth (helical spline forming tooth) 13 Outer punch

Claims (4)

[Claims] 1. A method of manufacturing a gear having a spur gear on an outer periphery and a helical spline on an inner periphery, comprising: a material forming an annular body; an outer tooth forming member having a spur gear forming tooth on an inner periphery; Preparing an internal tooth forming member having a helical spline forming tooth on the outer periphery, inserting the internal tooth forming member into the inner periphery of the external tooth forming member, and disposing the material in an outer peripheral space of the helical spline forming tooth. A helical spline is formed on the inner periphery of the material by pressing the material from both end surfaces in a state where the outer peripheral surface of the material is regulated, and the material is further continuously transferred to the inner peripheral space of the spur gear forming teeth. A method of manufacturing a gear, comprising forming a spur gear on the outer periphery of the material by extruding the material. 2. A method for manufacturing a gear having a spur gear on the outer periphery and a helical spline on the inner periphery, comprising: a material forming an annular body; a die having spur gear forming teeth on the inner periphery; A mandrel having splined teeth, inserted into the inner periphery of the die, a knockout pin movably provided in an annular space formed by the die and the mandrel, and an annular ring facing the knockout pin An outer punch provided movably in the space is prepared, the material is arranged in the outer peripheral space of the helical spline molding teeth, and the outer peripheral surface of the material is regulated by the cylindrical inner peripheral surface of the die. A helical spline is formed on the inner periphery of the material by pressing the material from both end surfaces with a knockout pin and the outer punch, and further continuously forming the outer material. Manufacturing method of the gear, which comprises forming a spur gear on the outer periphery of the material by extruding the material while pressing a punch to the inner peripheral space of the spur gear splines. 3. A back pressure device for applying a back pressure to the knockout pin, wherein the back pressure device presses the material from both end surfaces with the knockout pin and the outer punch, and then applies a back pressure to the knockout pin. 3. The method according to claim 2, wherein the pressure is released. 4. A chamfer forming part is provided on an end face of said knockout pin facing one end face of said material, and a chamfer is formed on one end face of said material at the same time as said helical spline is formed. 4. The method for manufacturing a gear according to any one of claims 3 to 3.