JPH04253540A - Production of gear - Google Patents

Abstract

PURPOSE:To eliminate the need for increasing the size of a device and to enhance the phase accuracy between both tooth profiles by setting the section in the radial direction of a blank material at approximately the same area ratio as the sectional area ratio in the radial direction of the molded gear. CONSTITUTION:The section in the radial direction of the blank material 5 is set at approximately the same area ratio as the sectional area ratio of the molded gear. The cylindrical blank material 5 is, therefore, pressed into a die 1 having the tooth profiles 2 for forming outside diameter teeth by means of a punch 3 having the tooth profiles for inside diameter teeth 4 under lower working load and both the inner and outer teeth are simultaneously formed no matter whether the relations between the inner and the outer teeth are the same in phase and no matter whether the number of teeth is the same. Then, the need for increasing the size of the device is eliminated.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is capable of forming both the inner and outer teeth by plastic working by pushing a cylindrical material into a die equipped with a tooth profile for forming outer diameter teeth using a punch equipped with tooth profiles for forming inner diameter teeth. This invention relates to a method for manufacturing gears that are formed simultaneously.

0002

[Prior Art] In recent years, attempts have been made to improve productivity by adopting plastic working technology in the field of gear forming, where cutting has been the mainstream, as described in Japanese Patent Application Laid-Open No. 64-22442. It's starting to look like this. However, even if plastic forming technology is actively adopted, especially when it comes to gears with both internal and external teeth, one tooth profile is first forged and then the other tooth profile is machined, or the other tooth profile is processed in two steps. Each piece was forged and formed.

0003

[Problems to be Solved by the Invention] Gear forging requires a high processing load, which not only leads to an increase in the size of the equipment, but also has fatal consequences such as shortening the life of the mold due to the heavy load placed on the equipment. There are drawbacks. In addition, when forming a gear with both internal and external teeth, the process is divided into two steps: forming the internal tooth profile and forming the external tooth profile, so there is also the drawback that the phase accuracy between the two tooth profiles is low.

0004

[Means for solving the problem] It is known that when a load is applied to a cylindrical material, the forging load can be lowered by deforming it in the tangential direction than in the radial direction even if the deformation rate is the same. It is being The present invention is a gear manufacturing method developed based on this theory, in which the cross section of the material in the radial direction is set to approximately the same area ratio as the cross-sectional area ratio in the radial direction of the molded gear.

[0005]

[Operation] By setting the cross-section of the material in the radial direction to approximately the same area ratio as the cross-sectional area ratio of the molded gear, the relationship between the inner and outer teeth will be different even if they are in the same phase or have the same number of teeth. However, since the deformation rate in the radial direction, which requires a large processing load, can be reduced, and the deformation rate in the tangential direction, which requires a small processing load, can be increased, the forging load can be set low.

[0006]

[Example] First, an apparatus for carrying out the method of manufacturing a gear according to the present invention will be explained based on the drawings. In FIG. A die with a tooth profile 2 and a punch 3 are cylindrical and equipped with a tooth profile 4 for forming internal teeth around the periphery, the die 1 and the punch 3 are arranged coaxially, the die 1 is fixed to a base, punch 3
moves up and down and presses into the recess 1a of the die 1.

Reference numeral 5 denotes a material, and this material 5 is basically cylindrical, and depending on the product shape of the molded gear, its cross-sectional area in the radial direction is approximately the same as the ratio of the cross-sectional area in the radial direction of the molded gear. The area ratio is set.

To give an example of a specific material shape, when forming a gear A in which both the inner and outer teeth have the same phase and the inner teeth 6 and outer teeth 7 alternately protrude, the radial cross-sectional area of the molded product A1 -A1, A2 -A2, A3 -A3
Since both have approximately the same area, they remain cylindrical and no preforming is necessary, as shown in FIG.

When forming a gear B of the type in which the inner and outer teeth have different phases and the inner and outer teeth 6 and 7 protrude in the same phase, the radial cross-sectional area of the molded product is B1 - B1
, B2 -B2 and B3 -B3 are different, so Fig. 3
It is preformed into a shape in which thick parts and thin parts are arranged alternately, as shown in FIG.

[0010] In the case of a gear C in which the numbers of both inner and outer teeth are different from each other, the cross-sectional area in the radial direction of the molded product is C1 - C1
, C2 - C2, and C3 - C3 change irregularly, and accordingly, the cross-sectional area of the material in the radial direction is also preformed into a shape that changes irregularly as shown in FIG.

The above embodiment is merely an example, and the shape of the material can be changed as appropriate depending on the phase of the waveform, the number and size of teeth, and the material has the same cross-sectional area in the radial direction as the forming gear. Not only can the length (thickness) in the radial direction be made the same, but it can also be adjusted in the axial direction (height) as shown in FIG.

0012

According to the present invention, a cylindrical material is pushed into a die having a tooth profile for forming an outer tooth by a punch having a tooth profile for forming an inner tooth with a small processing load, and both the inner and outer teeth are formed. Since molding can be performed simultaneously, there is no need to increase the size of the device, and it is possible to improve the phase accuracy between both tooth profiles.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a forming apparatus used in a gear manufacturing method according to the present invention.

FIG. 2 is an explanatory diagram showing the relationship between the raw material and the molded product according to the present invention.

FIG. 3 is another explanatory diagram showing the relationship between the raw material and the molded product according to the present invention.

FIG. 4 is yet another explanatory diagram showing the relationship between the raw material and the molded product according to the present invention.

FIG. 5 is an explanatory diagram showing an example of changing the material used in the gear manufacturing method according to the present invention.

[Explanation of symbols]

1...Die, 1a...Concave portion, 2...Tooth profile for forming outer diameter teeth,
3. Punch, 4. Tooth profile for forming internal teeth, 5. Material,
6. Inner tooth, 7. Outer tooth, 8. Preformed product, A.
B, C... Gears.

Claims (1)

[Claims] 1. A method for manufacturing a gear, in which both the inner and outer teeth are simultaneously formed by pushing a cylindrical material into a die having a tooth profile for forming an outer diameter tooth by using a punch having a tooth profile for forming an inner diameter tooth. A method for manufacturing a gear, wherein the cross section of the material in the radial direction is set to approximately the same area ratio as the cross-sectional area ratio in the radial direction of the molded gear.