JPH07279941A - Manufacture of main shaft for transmission - Google Patents

Abstract

PURPOSE:To prevent clearance from being produced between bushes to ensure the strength of a main shaft by providing splines on the main shaft for transmission over its entire length, and pressing bushes into the outside of the shaft with the shaft cooled to very low temperatures. CONSTITUTION:After a main shaft 1 on which splines are formed over its entire length, is cooled to very low temperatures using liquid nitrogen, etc., bushes 3a, 3b, 3c... equivalent to conventional stepped parts are pressed into on the main shaft, and hubs 4, 5... are spline-fitted in the splines 2 between 3a, 3b, 3c. Thus, machining, assembly of the main shaft are remarkably simplified, and no clearance is produced between the bushes during assembling the main shaft. Further, since a compressive load is constantly produced on the shaft 1, the strength of the shaft can be ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for facilitating processing and assembling of a main shaft of an automobile transmission.

[0002]

2. Description of the Related Art As shown in FIG. 2, a general shaft of this type is a shaft c having a thick stepped portion a in the center and a spline portion b in the middle thereof, which requires high processing accuracy. In addition to being a part, there was a problem that it took a lot of man-hours to process.

Here, if the main shaft is simply made into a total spline shaft, the force generated by the meshing of the gears is applied, which may cause fatigue damage. Then, by pressing the bush, the load will be received by this bush, but according to the generally used warm-fitting method in which the bush is heated to high temperature, the bush becomes the same temperature as the shaft after press fitting. At this time, the bush shrinks, a gap is generated between the bushes, a tensile load is generated in the shaft, and the strength between the bushes is significantly reduced.
Practicality is lost.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for ensuring the strength of a shaft without causing a gap between bushes.

[0005]

That is, according to the present invention, the main shaft of the transmission is used as the shaft of the total spline, and the bush corresponding to the conventional step portion is press-fitted in a state where the shaft is cooled to an extremely low temperature. The present invention proposes a method of manufacturing a main shaft of a transmission, which is characterized by the above.

[0006]

In the present invention, the main shaft of the total spline is cooled to an extremely low temperature by using liquid nitrogen or the like, and the bush is fitted so that no gap is generated between the bushes when the main shaft is assembled. Moreover, a compressive load is constantly generated in the shaft, and the strength is secured.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 is a main shaft having a spline 2 formed along its entire length, and this main shaft 1 corresponds to a conventional stepped portion when it is cooled to an extremely low temperature using liquid nitrogen or the like. The bushes 3a, 3b, 3c ... Which are to be pressed are press-fitted, and the hubs 4, 5, ... Are spline-fitted to the spline 2 between these bushings 3a, 3b, 3c.

[0008]

As described above, with the main shaft of the total spline being cooled to an extremely low temperature, the bush corresponding to the stepped portion is fitted, and then the predetermined gear is fitted to the spline portion. By doing so, it becomes possible to remarkably simplify the processing and assembling of the main shaft and maintain a predetermined strength.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a diagram showing a general form of a main shaft.

[Explanation of symbols]

 1 Main shaft 2 Splines 3a, 3b, 3c ... Bush, 4,5, ... Hub

Claims (1)

[Claims] 1. A main shaft of a transmission is a shaft of a total spline, and a bush corresponding to a conventional step portion is press-fitted in a state where the shaft is cooled to an extremely low temperature. Main shaft manufacturing method.