JPH06126372A - Manufacture of shaft having inner and outer sprines - Google Patents

Abstract

PURPOSE:To improve working precision by forge-forming an outer spline to the outer periphery at the one end part of a work, boring a guide hole on the end surface of the other end part of the work while using the outer spline as the working reference and forming an inner spline along the inner periphery thereof. CONSTITUTION:In a first process, the work 4 as a blank for shaft is forge- formed to almost the product shape. In a second process, the outer spline 7 is forge-formed along the outer periphery of the one end part of the work 4. In a third process, the guide hole 8 is bored on the end surface of the other end part of the work 4 while using the formed outer spline 7 as the working reference. In a fourth process, the inner spline 14 is forge-formed along the inner periphery of the guide hole 8. By this method, the shaft can efficiently be manufactured and the miniaturization and the lightening can easily be executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a shaft having inner and outer splines.

[0002]

BACKGROUND OF THE INVENTION Shafts with internal and external splines, for example input shafts for transmitting engine power to a transmission, are conventionally divided into several parts, each part being shaped in a suitable manner and then each part being formed in a suitable manner. It was manufactured using the joining method.

FIG. 7 shows an example of a conventional input shaft. In this case, the input shaft is the shaft part 1,
The sun gear portion 2 and the sleeve yoke portion 3 are divided into three parts, each part is machined, and then each part is joined as shown in the drawing. Reference numerals 8 and 18 are guide holes.

As another manufacturing method of the input shaft other than the above, for example, there is a method of integrally forging the sun gear portion 2 and the shaft portion 1 of FIG. 7 by forging an outer spline on the shaft portion. In addition, JP-A-4-8
In Japanese Patent No. 1242, an outer spline (for example, a ridge provided along the outer circumference of the sun gear portion 2 in FIG. 7) and an inner spline (for example, in the sleeve yoke portion 3 in FIG. 7) are formed on a workpiece that is a shaft material that has been processed into a predetermined shape in advance. There is disclosed an inner and outer spline molding device capable of simultaneously molding concave grooves provided along the inner circumference.

[0005]

However, when the input shaft is manufactured by the method of joining a plurality of parts which are manufactured separately, the manufacturing process becomes complicated because the whole manufacturing process is increased, and as a result, the productivity is lowered. It has the drawback of high manufacturing costs. Further, since the processing accuracy is different for each part, when the parts are integrally bonded, the mechanical strength of the bonded part is likely to be reduced, and the processing accuracy as a whole may be reduced. Further, in order to secure sufficient mechanical strength in the joint portion, the thickness of the joint portion of each portion must be increased, so that the size and weight of the input shaft are likely to increase.

On the other hand, in the method of using the inner / outer spline forming apparatus disclosed in Japanese Patent Laid-Open No. 4-81242, the inner / outer splines can be formed at the same time, but a work made of a shaft material preliminarily processed into a predetermined shape, It is necessary to use a work that has a hole for forming the inner spline at one end with a predetermined dimensional accuracy, and to set an appropriate processing standard in advance when forming the inner and outer splines at the same time. Since it must be done, the manufacturing becomes complicated.

The present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a shaft having inner and outer splines which is excellent in processing accuracy and mechanical strength and which is small and lightweight. It is to provide a manufacturing method that can be obtained.

[0008]

That is, a method of manufacturing a shaft having inner and outer splines according to the present invention comprises a first step of forging a work which is a shaft material into a substantially product shape, and a step of forming an outer circumference of one end of the work. Second step of forging the outer spline by forging, a third step of forming a guide hole in the end face of the other end of the work using the formed outer spline as a processing reference, and along the inner circumference of the guide hole And a fourth step of forging the inner spline.

In the first step, a work, which is a shaft material, is formed into a general shape of a product by using an appropriate forging method such as hot forging and warm forging. Properties such as the material and size of the work may be appropriately determined according to the purpose.
Further, in this step, a rough tooth shape is formed along the outer circumference of one end of the work on which the outer spline is to be formed in the next step.

Then, in a second step, the outer spline is forged along the outer circumference of one end of the work. Cold forging is preferably used as a method for forging the outer spline, whereby the rough tooth profile formed in the first step is further processed into a desired outer spline shape. The size and shape of the outer spline (for example, the number and shape of ridges) are appropriately determined so that the desired performance can be obtained.

In the third step, a guide hole is bored in the end face of the other end of the workpiece with the outer spline formed in the second step as a processing reference. When the formed outer spline is used as a processing reference, specifically, for example, a reference for positioning is brought into contact with one or more surfaces of the outer spline, and the reference is applied to the longitudinal direction and / or the longitudinal direction. It means to position the work in the direction. The guide hole may be bored by a suitable machining method, for example, a conventional method such as boring with a lathe. Further, the properties of the guide hole (for example, diameter, depth, etc.) are determined in consideration of the properties of the inner spline.

Finally, in the fourth step, the inner spline is forged along the inner circumference of the guide hole using the guide hole as a processing standard. As a method for forging the inner spline, it is preferable to use cold forging as in the case of the outer spline.

If desired, the shaft having the obtained inner and outer splines may be further finished.

[0014]

Since the guide hole is formed by using the outer spline as a processing reference, the coaxiality between the outer spline and the inner spline formed on the inner circumference of the guide hole can be easily ensured.

[0015]

The method of the present invention will be described in more detail by the following examples.

FIG. 1 shows an example of steps for manufacturing an automobile input shaft by the method of the present invention.
In the first step, a work, which is a shaft material, is hot or warm forged to obtain a work 4 formed into a general shape of a product as shown in FIG. In this step, a rough tooth profile is also formed along the outer periphery of one end of the work 4 in which the outer spline is to be formed in the next step. FIG. 2 shows the tooth profile I surrounded by the one-dot chain line in FIG. 2 (a) is shown in FIG. 1 (a).
2 (b) is a view of the tooth profile portion of FIG. 2 (a) as seen from the direction of arrow B. FIG. The rough tooth-shaped gear tooth 5 has a substantially spherical end.

In the second step, the work 4 is cold forged, and the outer spline 7 is formed by performing outer spline formation (precision production) and chamfer molding (chamfering of the gear teeth 5) as shown in FIG. 1 (b). To do. FIG. 3 shows the tooth profile II surrounded by the one-dot chain line in FIG. FIG. 3A is a view of the tooth profile portion of FIG. 1B viewed from the direction of arrow C, and FIG. 3B is a view of FIG. 3A viewed from the direction of arrow D. By the outer spline formation and the chamfer molding, the gear teeth 6 are chamfered at the ends to have an acute angle.

Next, in the third step, as shown in FIG. 1C, with reference to the end surface of the outer spline 7 (reference in the longitudinal direction) and the outer diameter of the outer spline 7 (reference in the direction orthogonal to the longitudinal direction). Work 4 using a lathe (not shown)
A guide hole 8 is formed in the end face of the other end of the. FIG. 4 shows the tooth profile III surrounded by the one-dot chain line in FIG. That is, the positioning member 10 is brought into contact with the end face 9 to serve as a reference in the longitudinal direction, and the gear tooth 6 is brought into contact with a collet chuck (accessory tool of a lathe) 11 to serve as a reference in a direction orthogonal to the longitudinal direction. Further, a retracting clamp 13 is brought into contact with the surface of the flange portion 12 opposite to the gear teeth 6 to hold the work 4.

Finally, in the fourth step, as shown in FIG. 1D, the inner spline 14 is formed by cold forging along the inner circumference of the guide hole 8 with the guide hole 8 as a reference. FIG. 5 shows an example of the inner spline forming die for forming the inner spline 14. In FIG. 5, reference numeral 15 is an upper mold, 16 is a lower mold, and 17 is a mandrel inserted into the guide hole 8 to form the inner spline 14. The lower mold 16 is held by air pressure (pressed in the direction of the thick arrow).

FIG. 6 shows an example of a shaft having inner and outer splines manufactured by using the method of the present invention. The shaft has a guide hole 18 in addition to the guide hole 8.

[0021]

According to the method of manufacturing a shaft having inner and outer splines of the present invention, since the guide hole is formed by using the outer spline as a processing reference with the above structure, the outer spline and the inner spline formed on the inner circumference of the guide hole are formed. The coaxiality can be easily ensured, and the processing accuracy of the obtained shaft as a whole is improved. Further, since the outer spline and the inner spline are sequentially formed on one work, the manufacturing efficiency is good, and the resulting shaft has no joint portion, so that the mechanical strength is particularly high compared with the conventional split-formed shaft. Excellent strength.

Further, since the shaft can be integrally molded, it is possible to easily reduce the size and weight of the shaft obtained as compared with the conventional separately formed shaft. Specifically, for example, as is clear from comparison between FIG. 6 and FIG. 7, it is possible to reduce the weight of the portion corresponding to the connecting portion between the sleeve yoke portion and the shaft portion of the conventional split shaft by about 200 g.

Further, since the method of the present invention can obtain the processing standard for forming the guide hole in the outer spline molding, the manufacturing process is simplified as compared with the conventional method using the inner and outer spline molding apparatus. .

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of a method for manufacturing a shaft having inner and outer splines of the present invention.

FIG. 2 is an enlarged view of a portion I surrounded by a one-dot chain line in FIG.

FIG. 3 is an enlarged view of a II portion surrounded by an alternate long and short dash line in FIG.

FIG. 4 is an enlarged view of a III portion surrounded by a one-dot chain line in FIG.

FIG. 5 is an explanatory diagram of a step of forming an inner spline on a work in the method of the present invention.

FIG. 6 is an explanatory view of an example of a shaft having inner and outer splines manufactured by the method of the present invention.

FIG. 7 is an explanatory view of an example of a shaft having inner and outer splines manufactured by a conventional method.

[Explanation of symbols]

 1 Shaft Part 2 Sun Gear Part 3 Sleeve Yoke Part 4 Work 5,6 Gear Tooth 7 Outer Spline 8,18 Guide Hole 9 End Face 10 Positioning Member 11 Collet Chuck 12 Flange Part 13 Retractable Clamp 14 Inner Spline 15 Upper Die 16 Lower Die 17 Mandrel

Claims (1)

[Claims] 1. A first step of forging a workpiece that is a shaft material to a substantially product shape, and a second step of forging an outer spline along the outer periphery of one end of the workpiece.
It is composed of a third step of forming a guide hole in the end face of the other end of the work using the formed outer spline as a machining reference, and a fourth step of forging the inner spline along the inner circumference of the guide hole. A method for manufacturing a shaft having inner and outer splines, comprising: