JPS629728A - Manufacture of cam shaft - Google Patents

Abstract

PURPOSE:To make it unnecessary to execute after-working of a cam piece by executing a surface treatment such as quenching and grinding, etc. to a cam surface of the cam piece of a steel material or a sintered material, and thereafter, fitting it externally to a pipe material, caulking the pipe material from the inside surface, and fixing the cam piece to the pipe material. CONSTITUTION:A cam piece is formed by forging a steel material, and becomes a finished product by performing a surface treatment such as induction hardening and grinding, etc. to its cam surface, and thereafter, fitted externally to a pipe material 2. Subsequently, when the pipe material 2 is caulked from the inside surface side, and the outside surface of the pipe material 2 is welded by pressure to a recessed part 3B of the inside peripheral surface of a pipe fitting hole 3A of the cam piece 3, the cam piece is formed as one body with the pipe material 2. Accordingly, as for the cam piece 3, working such as a formation of the cam surface, quenching of the cam surface, grinding, etc. can be performed in a stage of a single item, therefore, its after-working becomes unnecessary. Also, many cam pieces 3 can be worked in a lump. Furthermore, said working is executed in the pre-stage for fixing it to the pipe material 2, therefore, the work can be executed easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a camshaft that opens and closes intake and exhaust valves of an engine.

(Prior Art and its Problems) A cam that opens and closes an intake and exhaust valve at a set timing to intake and exhaust air from an engine cylinder is provided on a shaft that rotates in synchronization with a crankshaft.

The old camshaft is! The cam was integrally formed on the shaft by l'jL construction, casting, etc., and the cam surface was formed by post-processing by machining, but this increased the total weight of the camshaft and made it difficult for the vehicle This made it unsuitable for weight reduction.

Therefore, in recent years, a hollow vibrating material has been used for the camshaft, and a sintered cam piece is fixed to this pipe material, so that the camshaft can be made of pumice.

By the way, in order to fix the sintered cam piece to the pipe material, as shown in an example in FIG. The pipe material 2 is inserted into the hole 1A, the pipe material 2 is partially deformed by bulge processing, etc., and the pipe material 2 is press-fitted into the four parts 1B to be integrated.

However, as shown in FIG. 2, this type of cam has a protruding cam shape on a portion of its outer periphery and a thin wall on the other portion. Therefore, the recess 1B is formed on the inner surface of the vibrator fitting hole 1A at a position corresponding to the protruding cam part 1C, but when internal pressure is applied to the pipe material 2 to fix the sintered cam piece 1, the protruding cam There is a problem in that cracks are likely to occur at locations other than the portion 1C.

Therefore, it is necessary to form the sintered cam piece 1 thick in advance, and after fixing it to the pipe material 2, cut the cam surface and post-process it into a predetermined shape. Since it is necessary to fix the camshaft to the shaft, machining is not easy and the cost of the camshaft is high.

[Purpose of the invention]

The present invention has focused on the above-mentioned drawbacks of the prior art, and has been made with the aim of improving these.It is possible to produce camshafts with high efficiency by using a pipe material for the shaft, and also prevent cracking of cam pieces and post-processing. The present invention aims to provide a method for manufacturing a camshaft that eliminates the need for camshafts and that can be obtained at low cost.

[Summary of the invention]

In order to achieve the above object, the method for manufacturing a camshaft according to the present invention involves forming a cam piece from steel or sintered material, subjecting the cam surface of the cam piece to surface treatment such as hardening and polishing, and then fitting it onto a pipe material. However, the cam piece is fixed to a predetermined position of the pipe material by caulking the pipe material from its inner surface to form a camshaft, thereby eliminating the need for post-processing of the cam piece.

(Embodiments of the Invention) The present invention will be described below with reference to the embodiment shown in FIG. 1, using the same reference numerals for parts common to those in FIG.

The cam piece 3 is formed by forging from steel, and the cam surface is subjected to surface treatments such as induction hardening and polishing to form a finished product.The cam piece 3 is fitted onto the outside of the pipe material 2, and the pipe material 2 is pressurized from the inner side to form a pipe. The material 2 is integrated by pressing the outer surface of the material 2 against the four portions 3B of the inner peripheral surface of the vibrator fitting hole 3A of the cam piece 3. In this case, in addition to using the conventional fixing means shown in FIG. 2, the inner circumferential surface of the vibrator fitting hole 3A of the cam piece 3 is processed with unevenness such as an O-let shape, a spiral shape, and an axial unevenness strip. By doing so, the strength of caulking with the pipe material 2 can be increased. Further, as for the caulking means, any appropriate pressurizing means such as press-fitting a core metal into the inside of the pipe material 2, a bulge, etc. can be adopted.

Therefore the camshaft according to the invention! If the cam piece 3 is decided, the cam surface shape, cam surface hardening, polishing, etc. can be applied to the cam piece 3 as a single item, so it is possible to process a large number of cam pieces 3 at once, and the pipe material can also be processed. Since the machining is performed before fixing the camshaft to the camshaft 2, the work is easy and the camshaft can be obtained at a low cost.

〔Effect of the invention〕

As explained above, the method for manufacturing a camshaft according to the present invention includes forming a cam piece from a steel material or a sintered material,
After surface treatment such as hardening and polishing is applied to the cam surface of this cam piece, it is fitted onto the pipe material at a predetermined position, and the cam piece is fixed at a predetermined position on the pipe material by caulking the pipe material from its inner surface. Since the camshaft is formed, there is no need for post-processing of the cam piece, and the processing and surface treatment of the cam piece can be carried out at the same time.This greatly improves work efficiency and allows the cam piece to be machined to the specified accuracy. Since it can be made into a product immediately after caulking, it has various effects such as increasing manufacturing efficiency, being superior in productivity, and being able to be provided at low cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a camshaft formed according to the present invention, and FIG. 2 is an exploded perspective view of a conventional camshaft. 2... Pipe material, 3... Cam piece, 3Δ... Vibe fitting hole, 3B... Uneven processing. Applicant's agent Sato-Yuna 1 Figure C Houki 2 Figure Procedural amendment 8 August 1985 Commissioner of the Patent Office Michibe Uga Tono Rei Invention name Kamushi Left manufacturing method 3 Relationship with the case of the person making the amendment Patent applicant Hitoshi Fukasawa 4th generation
Personal statement (7) I"v>01(7') ili17: rf
fcJII+11 (7) R1-Contents of correction ``1'' on page 6, line 12 of the aS for this application ``1'' is corrected as follows. Yes. Furthermore, the hole end surface of the cam piece is also 1 in advance, so it may break during caulking. There's no 'no.'

Claims (1)

[Claims] A cam piece is formed from steel material or sintered material, and the cam surface of this cam piece is subjected to surface treatments such as hardening and polishing, and then fitted onto the pipe material at a predetermined position, and the pipe material is caulked from the inside. A method for manufacturing a camshaft, characterized in that the camshaft is formed by fixing the cam piece to a predetermined position on a pipe material, thereby eliminating the need for post-processing of the cam piece.