JPH0423143B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a camshaft made of steel that is a solid shaft or a hollow shaft, and assembly parts such as a cam lobe, a journal, and a gear that are separately manufactured are assembled on the outside of the camshaft. The present invention relates to a method of manufacturing an assembly type camshaft that is manufactured integrally by bonding, brazing, or liquid phase sintering.

[Prior art] Conventionally, when joining this type of assembled parts to a camshaft by brazing or liquid phase sintering, a part was attached to the outer circumferential surface of the camshaft in order to position the camshaft in the circumferential direction. One or more grooves are formed in the longitudinal direction, and protrusions into which the grooves fit are formed at desired positions on the inner peripheral surface of the fitting hole of the assembly part. In order to improve the performance, the shapes, dimensions, positions, etc. of the grooves and protrusions had to be manufactured accurately, which required a large number of manufacturing steps.

In addition, when this type of assembly parts are joined to the camshaft by liquid phase sintering, the assembly position of the assembly parts in the longitudinal direction of the camshaft will vary from part to part, and the assembly dimensions will vary. There was a drawback that they were not aligned.

The inventors of the present invention have conducted extensive research to find out the cause of this problem, and have found that the uneven assembly dimensions are due to the following causes. That is, Figures 1 and 2
As shown in the figure, when the cam lobe 10, which is a sintered assembly part, is fitted and assembled onto the camshaft 11 and put into a sintering furnace and subjected to liquid phase sintering, the cam lobe 10 is attached to the camshaft 11. It has become clear that the dimensions of the assembled parts after sintering are not uniform because the cam lobe 10 contracts around the position where joining was first started, and this position is not constant for each cam lobe 10.

For example, when the cam lobe 10 is assembled to the camshaft 11, as shown in FIG.
If the cam lobe 10 is first joined to the camshaft 11 at a point, after liquid phase sintering, the cam lobe 10 will contract around this point A as shown by the imaginary line in FIG. If the cam lobe 10 is first joined to the cam shaft 11, the cam lobe 10 will contract around point B after liquid phase sintering, as shown by the imaginary line in FIG. The above shrinkage phenomenon occurs not only in the cam lobe but also in other assembled parts such as sintered journals and gears. Therefore, the position of the assembled parts relative to the camshaft after liquid phase sintering changes depending on the initial joining point and is not constant.

The present inventors have found that by forming grooves instead of protrusions and inserting metal wires into the two grooves as a means for positioning the camshaft of the assembly parts in the periaxial direction, the manufacturing steps can be reduced. The present invention was completed by paying attention to this fact.

In addition, as a means for positioning the camshaft in the longitudinal direction of the sintered assembly, the shrinkage characteristics of the assembly described above are used to insert a metal wire rod with a melting point lower than the melting point of the assembly into the liquid phase of the assembly. 2 as a joining starting material during sintering
The present invention was completed based on the realization that the above-mentioned drawbacks can be overcome by inserting the connector into one of the grooves and actively creating a joining starting point for the assembled parts.

[Object of the Invention] The first object of the present invention is to provide a method for manufacturing a camshaft in which assembly parts such as cam lobes, journals, gears, etc. can be easily joined at predetermined positions around the camshaft with a small number of manufacturing steps. A second object of the present invention is to provide a method for manufacturing a camshaft in which the longitudinal assembly dimensions of the sintered assembly parts of the camshaft can be uniformly aligned with extremely high precision. .

[Structure of the Invention] The method for manufacturing a camshaft according to the present invention includes forming a groove in the longitudinal direction at one location on the outer peripheral surface of the camshaft,
On the other hand, a groove is formed on the inner circumferential surface of the fitting hole of the assembly part to be fitted to the camshaft, and the groove is opposed to the groove when the assembly part is placed at a predetermined position with respect to the camshaft; After fitting and arranging the assembly part on the camshaft so that both the concave grooves face each other, a metal wire is inserted into the both concave grooves to fix the assembly part to the camshaft. It is characterized by joining.

At this time, the connection of the assembled parts to the camshaft is as follows:
This can be done by brazing or liquid phase sintering, and in the case of liquid phase sintering, the assembled parts are made of sintered parts, and the metal wire is heated at a temperature lower than the liquid phase generation temperature of the assembled parts. If it is made of a metal that produces a liquid phase,
The metal wire serves as the joining starting material, which is desirable because it eliminates deviation of the assembly position of the assembly part in the direction around the axis of the camshaft from a predetermined position.

In particular, by forming protrusions on this low melting point metal wire,
When the metal wire is inserted into the double grooves, if only one convex portion contacts the double grooves, the welding starting point can be arbitrarily set at a desired position.

In addition, if the assembled parts consist of multiple parts, the low-melting point metal wire may be a short piece that is inserted into each part individually, or a long piece that is commonly inserted into the multiple parts. Good too. When a long material is used, it is desirable to form a convex portion for each component in accordance with a predetermined mounting interval of each component, since the assembly dimensions of a plurality of components to be assembled will be uniform all at once.

[Example] Next, an example of the present invention will be described in detail based on the drawings.

6 and 7 are cross-sectional views of a cam lobe and a camshaft in a method of manufacturing a camshaft according to a first embodiment of the present invention. The characteristic feature of this embodiment is that there is a groove 12 in the longitudinal direction at one location on the outer peripheral surface of the camshaft 11.
The cam lobe 10 is formed on the inner circumferential surface of the fitting hole 14 of the cam lobe 10 that fits into the cam shaft 11.
1, forming a groove 15 that faces the groove 12 when placed at a predetermined position relative to the groove 12,
After the cam lobe 10 is fitted onto the cam shaft 11 so that the lobes 15 face each other, the double concave grooves 12 and 15 are arranged.
The cam lobe 10 is fixed by inserting a metal wire 16 thereinto and joined to the cam shaft 11.

Here, the cross-sectional shape of each of the grooves 12 and 15 may be a rectangular combination as shown in FIG. 8 or a triangular combination as shown in FIG. 9. Further, the cross-sectional shape of the metal wire 16 may be square (FIG. 8) corresponding to the two grooves 12, 15, as long as it contacts both grooves 12, 15 at the same time.
15 may be circular (FIG. 9).

The cam lobe 10 and the camshaft 11 having such a configuration are joined by brazing or liquid phase sintering.
In the case of brazing, the cam lobe 10 is made of a member that can be brazed, and in the case of liquid phase sintering, the cam lobe 10 is made of a sintered member.

This manufacturing method eliminates the need to manufacture the shapes, dimensions, etc. of the grooves 12 and 15 with strict precision as in the case of conventional projections and grooves, and furthermore, the cam lobe 10 is attached to the camshaft
After the cam lobe 10 has been fitted to a predetermined position in the longitudinal direction of the cam lobe 10, the cam lobe 10 can be quickly assembled by simply making the groove 15 face the groove 12 and inserting the metal wire 16 into both grooves.

FIG. 10 is a longitudinal sectional view of a cam lobe and a cam shaft joined together in a method of manufacturing a camshaft according to a second embodiment of the present invention. The characteristic feature of this embodiment is that the cam lobe 10 and the cam shaft 11 are joined by liquid phase sintering, and the metal wire 16 is made of a metal that forms a liquid phase at a temperature lower than the liquid phase generation temperature of the cam lobe 10, such as copper. or copper alloy, aluminum or aluminum alloy, lead or lead alloy, tin or tin alloy, bismuth or bismuth alloy,
It is made of antimony or an antimony alloy, zinc or a zinc alloy, and furthermore, the metal wire 16 is formed into a short piece with a protrusion 17 at the end (the left end in this example). Note that this convex portion 17 is formed in the fitting hole 14 when the metal wire 16 is inserted into both the concave grooves 12 and 15.
The convex portion 17 is located at the center of the concave groove, and is dimensioned so that only the convex portion 17 contacts both concave grooves.

The cam lobe 10 having such a configuration is fitted onto the camshaft 11, and with the center position of the cam lobe 10 aligned with a predetermined position of the camshaft 11, a biconcave hole is inserted from one end (the left end in this example) of the fitting hole 14. If liquid phase sintering is performed after inserting the metal wire 16 into the grooves 12 and 15, the protrusion 17 of the metal wire 16 having a low melting point will melt first during sintering, so the center position of the fitting hole 12 will be The cam lobe 10 contracts based on . As a result, the assembly position of the cam lobe 10 does not change at all times, and the cam lobe 10
When a plurality of cam lobes are assembled to the camshaft 11, the assembly dimensions of each cam lobe are uniform.

FIG. 11 is a longitudinal sectional view of a cam lobe and a cam shaft joined together in a method for manufacturing a camshaft according to a third embodiment of the present invention. The characteristic feature of this embodiment is that the metal wire 16 shown in the second embodiment is made into a long member that is commonly inserted into a plurality of cam lobes 10, and the convex portions 19 are formed in accordance with the predetermined mounting intervals of each cam lobe 10. It is located at the point formed by each cam lobe.

A plurality of cam lobes 10 configured as described above are fitted to the camshaft 11, and the fitting hole 14 is inserted with the center position of the cam lobe 10 aligned with a predetermined position of the camshaft 11.
After inserting the metal wire 16 from one end into the double grooves 12 and 15 and setting one end of the long wire as a reference so that each convex part 19 is located at the center of the fitting hole 14, liquid phase sintering is performed. For example, as in the second embodiment, the cam lobe 10 contracts with respect to the center position of the fitting hole 14, and the assembly dimensions of a plurality of cam lobes can be made uniform all at once.

In the above example, a cam lobe is used as the sintered assembly part, but other sintered assembly parts such as journals and gears can be used in the same manner.

In addition, in the second and third embodiments, the reference position for assembling the cam lobe is the center position of the cam lobe, and the convex portion 17
and 19 are both arranged at the center position of the fitting hole 14, but the reference position of the cam lobe and the protrusion 17 are
and 19 are arranged at the respective ends of the cam lobe and the fitting hole, without being limited to the above example.

[Effects of the Invention] As described above, according to the present invention, a concave groove is formed on the outer peripheral surface of the camshaft, and the cam lobe, journal,
After forming a groove at a predetermined position on the inner circumferential surface of the fitting hole of an assembly part such as a gear, and placing the assembly part on the camshaft so that these grooves face each other,
By inserting a metal wire into the double-concave groove and fixing the assembled parts to the camshaft, there is no need to manufacture the shape, dimensions, etc. of the double-concave groove with the same exact precision as with conventional protrusions and grooves. Moreover, after fitting the assembly parts to the predetermined position in the longitudinal direction of the camshaft, all you have to do is to make both grooves face each other and insert the metal wire into both grooves.
Because the assembly parts can be assembled quickly,
The assembly parts can be easily joined at a predetermined position in the periphery of the camshaft with a small number of manufacturing steps.

In particular, when joining the assembled parts to the camshaft by liquid phase sintering, the assembled parts are made of sintered material, and the metal wire is brought into a liquid phase at a temperature lower than the liquid phase generation temperature of the assembled parts. If it is made of metal that produces
The metal wire serves as a joining starting material, and the assembly position of the assembly part in the axial direction of the camshaft can be matched with a predetermined position with extremely high accuracy.

In addition, by forming a convex part on this low melting point metal wire,
When this metal wire is inserted into the double-concave groove, if only one convex part contacts the double-concave groove at a predetermined position, the assembled parts will shrink in a certain direction with respect to the convex part. Therefore, the longitudinal assembly dimension of the camshaft of the assembly part does not always change, and can be made uniform without variation between camshafts.

Furthermore, when the assembled parts consist of multiple parts, it is possible to cut the low melting point metal wire into short pieces, insert each part separately, and position each part separately.
In addition, if this metal wire is made into a long material and a convex portion is formed on the long material for each component in accordance with the predetermined installation interval of each component to communicate with multiple components, the camshaft of multiple assembled components The assembly dimensions in the longitudinal direction can be made uniform all at once, and the number of assembly steps can be reduced.

[Brief explanation of drawings]

Figure 1 is a vertical sectional view of the assembled camshaft, Figure 2 is an enlarged cross-sectional view of Figure 1, and Figure 3 is the joining of the cam lobe and camshaft before liquid phase sintering in the conventional camshaft manufacturing method. 4 and 5 are longitudinal cross-sectional views of the cam lobe and camshaft before and after sintering shown in FIG. 7 is a cross-sectional view of FIG. 6, and FIGS. 8 and 9 are cross-sectional views of the grooves formed in the cam lobe and the camshaft, and the metal wire inserted into these grooves. 10 is a longitudinal cross-sectional view of the joint between the cam lobe and the camshaft in the method of manufacturing a camshaft according to the second embodiment of the present invention, and FIG. It is a diagram. 10: Cam lobe, 11: Cam shaft, 12, 15:
Concave groove, 14: Fitting hole, 16: Metal wire, 17, 1
8, 19: Convex portion.

Claims (1)

[Scope of Claims] 1. A longitudinal concave groove is formed at one location on the outer peripheral surface of the camshaft, while a groove is formed in the inner peripheral surface of the fitting hole of the assembly part of the sintered member that fits into the cam groove. When the assembly part is placed at a predetermined position with respect to the camshaft, a concave groove is formed opposite to the concave groove, and the assembly part is fitted onto the camshaft such that both the concave grooves face each other. In the method for manufacturing a camshaft, the method for manufacturing a camshaft includes inserting a metal wire into both grooves to fix the assembled part, and joining the assembled part to the camshaft by liquid phase sintering. A method for manufacturing camshafts in which the metal wire is a metal that forms a liquid phase at a temperature lower than that of the assembled parts. 2. The camshaft according to claim 1, wherein a convex portion is formed on the metal wire so that when the metal wire is inserted into the double concave groove, only one convex portion contacts the double concave groove. manufacturing method. 3. The method for manufacturing a camshaft according to claim 2 or 3, wherein the assembly part is composed of a plurality of parts, and the metal wire is a short piece inserted separately for each part. 4. A patent in which the assembly part consists of a plurality of parts, and the metal material is a long material that is commonly inserted into the plurality of parts, and a convex part is formed for each part in accordance with the predetermined installation interval of each part. A method for manufacturing a camshaft according to claim 2 or 3.