JP2002205137A - Manufacturing method of ring gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a ring gear which has short manufacturing time, is excellent in yield of the material, and is capable of reducing the manufacturing cost. SOLUTION: A first intermediate product 5 is obtained by forming a bottomed hole 2a having internal teeth 3 on the inner circumference by forging a material 30. Next, a second intermediate product 6 is formed by punching a hole bottom 19 of the bottomed hole 2a having the internal teeth 3 by a press to form a hole 2 having the internal teeth 3 and to form a second intermediate product 6. Then, the second intermediate product 6 is fitted in a setting groove part 8 of a fitting groove 11 of a die 7, and the pressure is applied to an upper part of the second intermediate product 6 by a punch 12 to form recesses 18 in an outer circumferential part of the second intermediate product 6 by a blade part 9, and to form the ring gear 4 with a part between the recesses 18 forming an arm 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ring gear having a hole having internal teeth on the inner periphery and an arm on the outer periphery.

[0002]

2. Description of the Related Art Conventionally, as a ring gear 4 used for a seat belt mechanism of an automobile, as shown in FIG. 11, a ring gear 4 having a hole having internal teeth on an inner periphery and an arm 1 on an outer periphery is known. ing. The ring gear 4 is used to drive up a seat belt of the vehicle when the vehicle collides. That is, a pinion 32 is provided on the drum 31 for winding the seat belt by the spring winding mechanism, and the pinion 32 is disposed in the hole 2 of the ring gear 4. The ring gear 4 is fixed to a base 32 that rotatably supports the drum 31 with pins 33, and the internal teeth 3 of the ring gear 4 and the external teeth 35 of the pinion 32 are not normally engaged. On the other hand, when receiving an impact such as a collision, the explosive provided at one end of the guide tube 34 explodes,
A steel ball (not shown) is fired from the guide tube 34, and the steel ball collides with the arm 1 protruding from the outer periphery of the ring gear 4, pushing off the pin 33 holding the ring gear 4 and rotating the ring gear 4. Then, the internal teeth 3 of the ring gear 4 and the external teeth 35 of the pinion 32 mesh with each other to wind up and drive the seat belt.

In manufacturing the ring gear 4 as described above, conventionally, the ring gear 4 has been manufactured in the order shown in FIG.

First, as shown in FIG. 10A, the raw material 30 is placed in a mold 36, and pressure is applied to the raw material 30 in the direction of the arrow in FIG. First
Is formed. In this case, the blade 3 of the mold 36
In FIG. 9, a slope 40 is formed to allow the material 30 to escape during molding. The material 30 is thicker than the final product in order to secure this escape. next,
The second intermediate product 38 is obtained by cutting the first intermediate product obtained as described above by cutting the portion A indicated by cross-hatching in FIG. 10B. In this cutting, a portion of the first intermediate product 38 for absorbing the escape of the material indicated by a in FIG. 10B is removed by cutting. Next, the second intermediate product 38 is further cut as shown in FIG. 10C to form the hole 2 and the projection 37 is formed to form the arm 1 on the outer peripheral portion. Get 41. Next, the internal teeth 3 are formed on the inner periphery of the hole 2 of the third intermediate product 41 by broaching. Finally, although not shown, the ring gear 4 is manufactured by performing pin hole processing.

[0005] In the above-described conventional example, since the internal teeth 3 are formed by broaching with a lot of cutting work, it takes a long time to manufacture, and a thick material is required as the raw material 30. There is a problem that the yield is low and the manufacturing cost is increased for these reasons.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing a ring gear capable of shortening a manufacturing time, improving a material yield, and reducing a manufacturing cost. It is an issue.

[0007]

According to the present invention, there is provided a method of manufacturing a ring gear, comprising the steps of:
A method of manufacturing a ring gear 4 having a hole 2 provided with a hole and having an arm 1 protruding on an outer peripheral portion, the material 30 being forged and having an inner tooth 3 on an inner periphery. Hole with bottom 2
a step of obtaining the first intermediate product 5 forming the first intermediate product 5a, and punching a hole bottom 19 of the bottomed hole 2a of the first intermediate product 5 by a press to form the hole 2 having the internal teeth 3 on the inner periphery thereof. Product 6
And a molding groove 10 in which the upper portion of the mold 7 has a setting groove portion 8 having the same inner peripheral shape as the outer peripheral shape of the second intermediate product 6 and the lower portion has a blade portion 9 protruding from the inner wall. A fitting groove 11 is formed, and the inside of the fitting groove 11 has the same outer peripheral shape as the inner peripheral shape of the forming groove portion 10 and the inner periphery has a second shape.
A sleeve 13 having the same shape as the hole 2 provided with the internal teeth 3 of the intermediate product 6 is vertically movably housed, and has the same cross-sectional shape as the hole 2 provided with the internal teeth 3 of the second intermediate product 6 and has an outer peripheral portion. A guide body 16 having guide teeth 14 meshing with the internal teeth 3 is disposed in the fitting groove 11 of the mold 7, and the guide teeth 14 of the guide body 16 mesh with the sleeve teeth 15 on the inner periphery of the sleeve 13. The upper part of the guide body 16 is protruded from the sleeve 13, the second intermediate product 6 is fitted into the setting groove 8 of the fitting groove 11, and the hole 2 of the second intermediate product 6 is fitted into the upper part of the guide body 16 and the hole 2. Internal teeth 3 around
Is engaged with the guide teeth 14 on the outer periphery of the guide body 16, and has the same outer peripheral shape as the inner peripheral shape of the forming groove portion 10 having the blade portion 9 protruding from the inner wall, and the relief groove portion 17 provided on the outer periphery has the blade portion 9.
A pressure is applied to the upper portion of the second intermediate product 6 by the punching punch 12 having a positional relationship overlapping in plan view, and a concave portion 18 is formed on the outer peripheral portion of the second intermediate product 6 by the blade portion 9 to form a portion between the concave portions 18. Forming the ring gear 4 which has become the arm 1, and thereafter, protruding the ring gear 4 by the sleeve 13 and taking out the ring gear 4 from the mold 7.

By employing such a method, a first intermediate product 5 is formed by forging to form a bottomed hole 2a having an inner tooth 3 on the inner periphery, and then the inner product 3 is provided by pressing. After the hole bottom 19 of the bottomed hole 2a is punched out by a press to form the hole 2 having the internal teeth 3 on the inner periphery to obtain the second intermediate product 6,
The second intermediate product 6 is set in the mold 7 and the punch 1
By applying pressure to the upper part of the second intermediate product 6 by means of 2 and forming the concave portion 18 on the outer peripheral portion of the second intermediate product 6 by the blade portion 9, the ring gear 4 having the arm 1 between the concave portions 18 is formed. In manufacturing the ring gear 4 having the hole 2 provided with the internal teeth 3 and having the arm 1 formed on the outer periphery,
Forging, pressing, and punching can be used except for the finishing cutting process, eliminating the need for time-consuming broaching as in the past. It is.

The hole 2 of the second product 6 is fitted into the upper part of the guide body 16, and the internal teeth 3 around the hole 2 are engaged with the guide teeth 14 on the outer periphery of the guide body 16, and pressure is applied by the punch 19. In addition, since the punching is performed by processing with the blade portion 9, the intermediate product 6 is prevented from escaping to the outside by the inner wall of the fitting groove 11, and the guide body 16.
As a result, the material is prevented from escaping inwardly, and punched chips are discharged only from the escape groove 17 provided on the outer periphery of the punching punch 12, so that molding can be performed with high precision.

Further, the ring gear 4 is engaged with the blade portion 9 of the mold 7 for positioning, and the ring gear 4 and the guide body 16 are engaged and positioned. By positioning the internal teeth 3 of the inner periphery by meshing with the internal teeth 3, the internal teeth 3 of the intermediate product 6 and the blades 9 of the mold 7 can be used as they are by using the internal teeth 3 provided in the holes 2 required for completion. Can be positioned so as to have a predetermined positional relationship, and the internal teeth 3 and the arm 1 can be formed in an accurate positional relationship by a simple method. Moreover, the positioning member can be formed by using the guide body 16 which is a member for preventing the material 30 from escaping to the inside and the sleeve 13 which is a member for knocking the product out of the mold. is there.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the accompanying drawings.

The ring gear 4 to be manufactured according to the present invention is used for a seat belt mechanism of an automobile. As shown in FIG. 2, the ring gear 4 has internal teeth 3 on an inner periphery and a plurality of arms 1 on an outer periphery. It has a protruding structure.

The manufacturing of the ring gear 4 having the structure as shown in FIG. 2 is performed as follows.

First, a raw material 30 as shown in FIG. 1A is forged to form a first intermediate product 5 having a bottomed hole 2a provided with internal teeth 3 on the inner periphery as shown in FIG. 1B. Is what you get. As shown in FIG. 3, the step of obtaining the first intermediate product 5 is performed by a forming punch 22 having a disk-shaped material 30 set in a forging die 20 and a tooth forming projection 21 provided on the outer periphery. A first intermediate product 5 is formed by forging to form a bottomed hole 2a having an internal tooth 3 on the inner periphery as shown in FIG. 1 (b). The step of obtaining the first product 5 is a forging step. In FIG. 3, reference numeral 23 denotes a knockout spacer, which knocks out the first intermediate product 5 from the forging die 20 by moving the knockout pin 24 after processing the first intermediate product 5 and using the knockout spacer 23. It has become.

Next, the hole bottom 19 of the bottomed hole 2a of the first intermediate product 5 is punched out by a press to form the hole 2 having the internal teeth 3 on the inner periphery to form the second intermediate portion as shown in FIG. The product 6 is formed. The step of obtaining the second intermediate product 6 is a pressing step.

Next, the second intermediate product 6 is machined in a punching step, and has a ring gear 4 as shown in FIG. 1D having inner teeth 3 on the inner periphery and a plurality of arms 1 protruding on the outer periphery. Is to manufacture.

This punching step is performed by a punching device as shown in FIG. The punching device includes a mold 7 and a punch 12. The mold (die) 7 has a fitting groove 11 opened upward, and the upper part of the fitting groove 11 is a setting groove 8, and a lower part of the forming groove 8 communicates with the setting groove 8. It is 10.

The setting groove 8 constituting the upper part of the fitting groove 11 has the same inner peripheral shape as the outer peripheral shape of the second intermediate product 6, and the length of the setting groove 8 in the vertical direction is as described above. The length is set to be longer than the vertical length of the second intermediate product 6. A plurality of blades 9 project from an inner wall of a forming groove 10 which forms a lower portion of the fitting groove 11.

A sleeve 13 is provided in the fitting groove 11 so as to be movable up and down. The sleeve 13 has the same outer peripheral shape as the inner peripheral shape of the molding groove 10 and the inner periphery is provided with the internal teeth 3. It has the same shape as the hole 2. That is, a fitting groove 26 for fitting with the blade portion 9 is formed on the outer periphery of the sleeve 13, and the sleeve teeth 1 are formed on the inner periphery of the sleeve 13.
5 are formed. Sleeve 13 is knockout pin 2
By driving 5, the inside of the fitting groove 11 moves up and down.

A guide 16 is provided at the center of the fitting groove 11 of the mold 7, and the lower end of the guide 16 is attached to the bottom of the fitting groove 11. The guide body 16 has the same cross-sectional shape as the hole 2 of the second intermediate product 6, and the guide teeth 16 are formed on the outer periphery of the guide body 16 so as to mesh with the internal teeth 3 formed on the inner periphery of the hole 2. .

Sleeve teeth 15 on the inner circumference of the sleeve 13
, And the fitting groove 26 on the outer periphery of the sleeve 13 is fitted with the blade portion 9. Therefore, the blade 9, the sleeve 13, and the guide body 16 are positioned in a plan view, and the sleeve 13 includes the blade 9, the guide 1.
6 is movable in the vertical direction while being positioned in a plan view.

The punching punch 12 has the same outer peripheral shape as the inner peripheral shape of the forming groove 10, and has a relief groove 17 having the same outer peripheral shape as the blade 9 protruding from the inner wall of the forming groove 10 on the outer peripheral surface. The clearance groove portion 17 has a positional relationship to overlap with the blade portion 9 in a plan view.

Thus, the second intermediate product 6 is transferred to the mold 7
The hole 2 of the second intermediate product 6 is fitted into the upper part of the guide body 16 and the internal teeth 3 around the hole 2 are engaged with the guide teeth 14 on the outer periphery of the guide body 16. . By engaging the internal teeth 3 of the second intermediate product 6 with the guide teeth 14 of the guide body 16 in this manner, the second intermediate product 6 can be positioned at a predetermined position of the mold 7 in plan view.

As described above, the second intermediate product 6 is
Is pressed in the upper part of the second intermediate product 6 by the punch 12 and the concave portion 18 is formed in the outer peripheral portion of the second intermediate product 6 by the blade 9 in a state where is positioned in a plan view. In this case, when pressure is applied from above by the punch 12, the internal teeth 3 of the second intermediate product 6
6 are guided by the guide teeth 14 and moved downward while being positioned in a plan view, the recesses 18 are formed in the outer peripheral portion by the blade 9, and the portion between the recesses 18 is the arm 1.
Is formed. Therefore, in the ring gear 4 thus formed, the positional relationship (phase relationship) in plan view between the internal teeth 3 formed on the inner periphery and the arm 1 formed on the outer periphery is equal to the predetermined positional relationship as designed. It is formed so that it becomes. In the above punching, the punching waste 27 escapes upward from the escape groove 17 provided in the outer peripheral portion of the punching punch 12. The punching waste 27 has a shape as shown in FIG.

After punching as described above, the punch 12 is moved upward,
5, the sleeve 13 is moved upward, and the sleeve 1 is moved.
The ring gear 4 is pushed upward by 3 to be taken out of the mold 7.

The ring gear 4 formed as described above is subjected to finish cutting as shown in FIG. 1 (e), and thereafter, though not shown, is subjected to pin hole processing as in the prior art to complete the finished product. It is assumed that.

[0027]

As described above, according to the first aspect of the present invention, a step of forging a material to obtain a first intermediate product in which a bottomed hole having internal teeth is formed on the inner periphery. Forming a second intermediate product by punching the bottom of the bottomed hole provided with the internal teeth by pressing to form a hole having the internal teeth on the inner periphery, and inserting the second intermediate product into a mold fitting groove. The ring gear in which the concave portion is formed on the outer peripheral portion of the second intermediate product by the blade portion by applying pressure to the upper portion of the second intermediate product by the punching punch, and the portion between the concave portions becomes an arm. The third step is to form the ring gear and then remove the ring gear from the mold by protruding the ring gear from the mold. In order to manufacture a ring gear having a hole provided with internal teeth and an arm formed on the outer periphery, finishing cutting is performed. Forging, pressing, and punching are sufficient except for the process. It does not require time-consuming broaching, and it requires only cutting for the final finishing, which can greatly reduce the manufacturing time. The yield of the material is good, and for these reasons, the manufacturing cost can be reduced as compared with the related art. Also, the hole of the second intermediate product is fitted into the upper part of the guide body, and the internal teeth around the hole are engaged with the guide teeth on the outer periphery of the guide body, and pressure is applied by a punch to be processed by the blade portion to perform punching. So do
In the intermediate product, the material is prevented from escaping outward by the inner wall of the fitting groove, and the material is prevented from escaping inward by the guide body. It can be molded with high accuracy. Further, the ring gear is engaged with the blade of the mold and positioned, and the ring gear and the guide are engaged and positioned, and the guide is engaged with the internal teeth of the inner periphery of the hole of the intermediate product. By positioning the internal teeth of the intermediate product and the cutting edge of the mold by using the internal teeth provided in the holes required for completion, the positioning can be performed so that the predetermined positional relationship is established. , The inner teeth and the arms can be formed in a precise positional relationship by a simple method, and a very accurate ring gear can be manufactured by a simple method.
As a positioning member, it is possible to use the guide body, which is a member for preventing the material from escaping to the inside of the material, and the sleeve, which is a member for knocking the product out of the mold, so that the manufacturing apparatus is simplified. In addition to this, it can be manufactured by a simple method, and the manufacturing cost can be reduced in this respect as well.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a manufacturing order of the present invention.

FIG. 2 shows a ring gear manufactured according to the above;
(A) is a plan view and (b) is a sectional view.

FIG. 3 is a cross-sectional view showing the forging device of the above.

FIG. 4 is an explanatory view showing the punching apparatus of the above.

FIG. 5 is a sectional view taken along line AA of FIG.

FIG. 6 is a sectional view taken along line BB of FIG.

FIG. 7 is a sectional view taken along line CC of FIG. 4 of the above.

FIG. 8 is a sectional view taken along line DD of FIG.

9A is a sectional view of a blade portion, FIG. 9B is a sectional view of a sleeve, FIG. 9C is a sectional view of a guide body,
(D) is a cross-sectional view of the punching punch, and (e) is a cross-sectional view of the punching waste.

FIG. 10 is an explanatory view showing a manufacturing order of a conventional example.

FIG. 11 is an explanatory diagram showing a use state of a ring gear.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arm 2 hole 2a Bottom hole 3 Internal teeth 4 Ring gear 5 First intermediate product 6 Second intermediate product 7 Mold 8 Set groove 9 Blade 10 Molding groove 11 Fitting groove 12 Punching punch 13 Sleeve 14 Guide teeth 15 Sleeve teeth 16 Guide body 17 Escape groove 18 Recess 30 Material

Claims (1)

[Claims] 1. A ring gear manufacturing method for manufacturing a ring gear having a hole provided with internal teeth on an inner periphery thereof and having an arm protruding on an outer periphery thereof. Obtaining a first intermediate product forming a bottomed hole with teeth, and punching a bottom of the bottomed hole of the first intermediate product with a press to form a hole having internal teeth on the inner periphery to form a second intermediate product. A step of forming a product, and a fitting groove in which the upper portion is a setting groove portion having the same inner peripheral shape as the outer peripheral shape of the second intermediate product and the lower portion is a forming groove portion in which a blade portion protrudes from the inner wall. A sleeve having the same outer peripheral shape as the inner peripheral shape of the molding groove portion and the inner periphery having the same shape as the hole provided with the inner teeth of the second intermediate product is formed inside the fitting groove so as to be vertically movable. (2) Guide teeth having the same cross-sectional shape as the holes provided with the internal teeth of the intermediate product and meshing with the internal teeth on the outer peripheral portion Is formed in the groove of the mold, the guide teeth of the guide body are engaged with the sleeve teeth on the inner periphery of the sleeve, and the upper part of the guide body is protruded from the sleeve. And the hole of the second intermediate product was fitted into the upper part of the guide body, the internal teeth around the hole were engaged with the guide teeth on the outer periphery of the guide body, and the blade part was protruded from the inner wall. The punching punch which has the same outer peripheral shape as the inner peripheral shape of the forming groove portion and the relief groove portion provided on the outer periphery overlaps the blade portion in plan view and applies pressure to the upper portion of the second intermediate product by the blade portion is used. A third step in which a concave portion is formed in the outer peripheral portion of the second intermediate product to form a ring gear in which a portion between the concave portions serves as an arm, and thereafter, the ring gear is protruded by a sleeve and removed from the mold. Method of manufacturing a ring gear, wherein.