JPH0429665Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to the structure of a power transmission shaft such as a half shaft of a model car.

FIG. 2 is a partial plan cross-sectional view of the power transmission section of the model car. Input from a prime mover (not shown) is transmitted to wheels d via a differential device a, a half shaft b, and further a wheel shaft c. The present invention relates to an improvement of the half shaft b, which is extremely important for power transmission.

(Prior art) As is clear from FIG. 2, this half shaft b has a spherical joint part b'' at both ends of the shaft part b'. This spherical joint part b'' further has a plurality of radial legs. It is designed to transmit power. Conventionally, the spherical joint part b'' having a plurality of legs has been molded integrally with the shaft part b' out of plastic, or by processing metal.
With plastic molding, even complex shapes can be easily molded, but there are problems with strength or accuracy.

Next, for the metal molded one, a spherical joint part b'' with two legs was machined out, a hole was drilled into this, and a piano wire was shrink-fitted into this to form the shaft part b' (No. (Figure 3).Since the shaft and spherical part are not integrated, there are of course problems in quality control, but
There were also problems in terms of productivity.

Alternatively, the spherical joint part b'' and the shaft part b' are made integrally by machining, and a hole is later drilled through the center of the spherical part, and a pin is shrink-fitted or brazed thereto.

In general, a power transmission shaft such as a half shaft has no problem when transmitting power in a straight line, but when transmitting power at a certain angle, slippage occurs at the joint, reducing speed and power transmission efficiency. Therefore, in order to prevent the joint from slipping, it is preferable that the spherical part has at least four legs.

However, apart from molding with synthetic resin,
In the case of metal forming, there are the following problems. That is, when the legs are machined integrally with the spherical part as described above, only two legs can be machined, and four legs are impossible in terms of cost or efficiency.

In addition, if the spherical part and the shaft part are made integrally and a foot is to be added later, a hole is drilled through the center of the spherical part and a pin is shrink-fitted or brazed into this, but the pins meet at the center. Even if the hole is drilled, it is not possible to insert a pin crosswise through the hole. If the pins are implanted without passing through the center, it is possible to have four legs, but due to strength issues, large amounts of power cannot be transmitted.

(Problems to be Solved by the Invention) In view of the problems of the prior art, the joint part of the half-shaft in a model car, which is subject to strong impacts at extremely high speeds, has four legs, and is made of metal, and the half-shaft is made of one piece. This is what we are trying to provide.

(Solution by invention) Consisting of a pair of joint parts and an intermediate shaft part integrally molded with resin between them, the joint part becomes a shaft part and a spherical part integral with the shaft part. It has a plurality of legs that are integrally formed with a spherical part in a radial direction perpendicular to the shaft part, and these legs are integrally formed by metal forging.

(Example) FIG. 1A shows a half shaft according to the present invention, which is composed of a joint part B consisting of a spherical part 1 and a shaft part 2, and an intermediate shaft part 5. Reference numeral 3 denotes four legs provided radially on the spherical part 1 and perpendicular to the shaft part 2. A plurality of legs 3, particularly four legs, is preferred from the viewpoint of power transmission efficiency, but two legs may be used. A knurling 4 is provided at the end of the shaft portion 2 integral with the spherical portion 1 formed in this way.
is engraved.

Now, two joint parts B are prepared, and the intermediate shaft part 5 is formed by covering the knurling parts 4 with resin, thereby forming the integral half shaft A.

The joint portion B is made of metal and has four legs 3, and these spherical portions 1 and legs 3 are integrally formed by forging. A thin burr is deposited between the legs 3 during molding, but it is later cut off in one shot using a press or the like to complete the joint part B.

Shaft part 2 of joint part B made in this way
A knurling 4 is machined on the end of the shaft, and an intermediate shaft portion 5 is integrally molded with synthetic resin.

(Effects) Since the joint part B having the spherical part 1 with legs is integrally formed by metal forging, production can be extremely efficient, and the finishing accuracy is also outstanding.

Since the part of the knurling 4 at the end of the shaft is covered with resin for molding the intermediate shaft part, an extremely tight fit is achieved at this part, and a completely integrated half shaft is completed.

Since the shaft part 2 can be processed with high precision by forging,
This part can be made thinner. Therefore, during assembly, the space in this part may be narrow, and there is no need to worry about the vicinity of the joint coming into contact with other parts as in the past.

[Brief explanation of the drawing]

Figure 1 shows a half shaft according to the present invention. Figure 2 is a partially detailed sectional view of the power transmission section of the model car. Figure 3 shows the spherical joint of a conventional metal half shaft. In the figure, A... Half shaft, B... Spherical joint part, 1... Spherical part, 2... Shaft part, 3
...4 legs, 4...knurling, 5...middle shaft.

Claims (1)

[Claims for Utility Model Registration] 1. Consists of a pair of joint parts B and an intermediate shaft part 5 integrally molded with resin between them, the joint part B having a spherical shape integral with the shaft part 2 and the shaft part 2. The spherical part 1 is provided with a plurality of legs 3 that are radially provided integrally with the spherical part so as to be perpendicular to the shaft part 2, and these legs are integrally formed by metal forging. Power transmission shaft for model cars. 2. A power transmission shaft for a model automobile according to claim 1, wherein the end of the shaft portion 2 is knurled.