JPS5853337A - Working method of driving shaft - Google Patents

Abstract

PURPOSE:To manufacture a driving shaft whose fatigue characteristic is excellent, by using a pipe whose inside diameter is equal to the outside diameter of a spline of a driving force transfer part, expanding the pipe by leaving the coupling part, and coupling both of them. CONSTITUTION:Internal pressure by a pressurized fluid is loaded onto the inside surface of a pipe 1 through a hole of a center shaft 3. By the pressurized fluid and axial force, the pipe 1 is deformed in accordance with a die 5. A driving force transfer part 2 is cold-pushed into a pipe 6 worked by internal pressure forming and the pipe 6 and the driving force transfer part 2 are coupled. In this way, as for the pipe diameter expanded part by the pressurized fluid, its strength is raised by pressure hardening and residual stress. Also, the outside surface of the pipe 6 contacts the die, and its surface state becomes satisfactory.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of machining a drive shaft of an automobile (FF vehicle), for example. In recent years, there has been an increasing demand for lighter weight and quieter automobile parts based on the desire to improve reliability and lower fuel consumption.

A hollow shaft is used for the driving shaft, such as a drive shaft, and a driving force transmission part such as a constant velocity joint manufactured in a separate process is integrated via a spline, and the driving force is transmitted to the driven side. There is something I am doing. FIG. 1(a) shows the pipe 1 and the aforementioned driving force transmission section 2 before the drive shaft is processed, and FIG. 1(b) shows the drive shaft after the processing.

Conventionally, methods for processing such drive shafts include the following methods.

(4) In Fig. 1(a), a pipe having an inner diameter slightly larger than the outer diameter of the spline of the driving force transmission section 2 is shown in Fig. 1(1).
) As shown in Figure 2, the method involves drawing the ends of both ends and caulking the spline parts by cold swaging.

(B) As shown in FIG. 1(C), a method of joining a member including a driving force transmitting portion and a pipe by friction welding.

(0) A method of integrally machining the driving force transmission part using a solid shaft.

However, the amount of deformation caused by the processing method is strong and the amount of deformation is large, which causes deterioration of the material in the part concerned, and furthermore, there is a possibility that vertical cracks may occur on the inner surface of the groove due to drawing wrinkles. Further, although it is often used as a raw material pipe on an electric resistance welded pipe, there is a high possibility that the member will be damaged from the electric resistance welded part due to the difference in hardness and workability between the electric resistance welded part and other parts during this heavy processing.

Furthermore, tensile residual stress occurs after machining, and the notch effect due to the spline, the springback after machining, and the meshing part with the spline, due to the swaging process.
Since the cracks become localized depending on the direction of rotation, the cracks tend to develop. As described above, depending on the processing method, problems arise in the fatigue properties of the electric resistance welded portion and other areas. Processing method (B)l (0: In the case of 0, there are still problems that need to be solved in each process from the standpoint of reliability and quantification. In particular, high screw stiffness cannot be obtained, there are problems with fatigue properties, There are disadvantages such as complexity.

The present invention is intended to solve the above-mentioned drawbacks, and its gist is to use a pipe having an inner diameter approximately equal to the outer diameter of the spline of the driving force transmission section, leaving only the joint portion with this transmission section, and The drive shaft is characterized in that the inner and outer diameters of the parts are plastically deformed by pressurized fluid to expand the pipe, and in the subsequent process, the pipe is weakly machined in cold or warm □111 to join the two parts. It's in the processing method.

In the following, according to the processing method of the present invention, internal pressure (detailed in detail with reference to the drawings) is applied to the inner surface of each tube. In order to facilitate deformation, the chuck 4 allows the loading of an axial compressive force on the nozzle. Due to the pressurized fluid and axial force, the Tsuquib deforms according to the die 5. The obtained Tsukuib is shown in Figure 2 (b).
The shape will be as shown in . 3 to 5 show a method of connecting the molded pipe and the driving force transmission section. First, Figure 3 (
In a), the L-shape is formed by internal pressure molding, and in the figure (b), the joint part between the nine-arm rib and the spline is processed by internal pressure molding.
It is formed as follows. The joint manufactured in this manner has advantages such as a small amount of processing and the generation of compressive residual stress. Furthermore, the same effect can be obtained even if the joint is processed by shrink fitting instead of cold. Further, as shown in FIG. 4, a nozzle having an inner diameter slightly larger than the outer diameter of the spline is formed by internal pressure, and the joint portion is caulked using a die 7. In this case, there are advantages that the amount of machining is smaller than in conventional machining, and that the caulked portions are well connected without depending on the direction of rotation unlike swaging machining.

If processed between e1, the mechanical state will be further improved. FIG. 5 shows a method of joining two driving force transmitting parts to the tip of a Pizoro processed by internal pressure forming by friction welding. This method makes it possible to manufacture a drive shaft that is lighter in weight than conventional methods, and the process is also simplified.

The processing methods shown in FIGS. 3 to 5 above use the deformation means using pressurized fluid shown in FIG. 2 as a basic manufacturing method, and in any case, they have the following advantages.

The part where the diameter of the pipe is enlarged due to pressurized fluid is hardened due to pressure and residual stress.
Its obscurity increases. The surface quality of the outer surface of the tube becomes good due to contact with the die. It was. There are no vertical cracks on the inner surface of the e-vebe, and the stress state is good due to the residual compression. Furthermore, through appropriate processing and control, it is possible to suppress variations in the wall thickness of the pipe diameter enlarged section. Since the portion connecting the driving force transmitting portion via the spline is lightly machined, the metallurgical structure and mechanical condition of the connection portion are good. Furthermore, the occurrence of rotation-dependent notches caused by the swaging process can be suppressed. Therefore, the drive shaft processed according to the present invention has improved fatigue characteristics compared to the case of the first-mentioned processing method (4). Furthermore, if the joint part of the pipe is heated and processed in a wet environment, the residual stress will make the mechanical condition better than ever, and the Q1 fatigue properties will also improve. The present invention has the above-mentioned remarkable effects.

Hereinafter, the effects of the present invention will be more concretely shown by way of examples.
．． 0- automotive steel pipe 8TKM13B (JI83445
), and as shown in Figure 2 (a), a maximum of 800
The tube was expanded by applying an internal pressure of 'kai/cat and an axial compressive force proportional to this, and a tube having the shape shown in Fig. 2) and an outer diameter of 60 mm at the expanded tube portion was obtained. The shape and properties were good, and there was little variation in wall thickness. Using this, it was connected to the driving force transmission part in cold and warm conditions as shown in FIG. The obtained drive shaft was subjected to a torsional fatigue test, and the fatigue properties were better than those obtained by the processing method (A) mentioned above, and it is thought that the possibility of member breakage is reduced.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the conventional method of forming a drive shaft and its usage, and Fig. 2 is a schematic diagram showing the method of forming the drive shaft according to the present invention.
A schematic diagram showing the R-pipe forming method, and FIGS. 3 to 5 are schematic diagrams showing a method of connecting a pipe formed by pressurized fluid and a driving force transmission section. l...Material! Eve, 2... Drive force transmission section, 3... Central shaft, 4... Chuck, 5... Die, 6... Molding pipe, 7... caulking die. Agent Patent attorney Masamitsu Akizawa (a) (b CC) 11 7'? Figure 4 Figure 5

Claims (1)

[Claims] (1) Using a pipe with an inner diameter approximately equal to the spline outer diameter of the driving force transmission part, leaving only the part connected to this transmission part, the inner and outer diameters of the other parts are plastically deformed by pressurized fluid. A method for machining a drive shaft, which comprises expanding the tube and, in the subsequent step, subjecting the tube to weak cold or warm working to join the two.