JPH0368257B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temporary fixing structure for manufacturing an assembled camshaft by bonding component parts such as a cam lobe and journal to a shaft by liquid phase sintering.

In the manufacture of prefabricated camshafts, components such as cam lobes and journals must be bonded to predetermined positions on the shaft during the liquid-phase sintering process, so accurate axial and circumferential positioning of these components relative to the shaft is critical. This is an important issue. Conventionally,
Such positioning has been performed by providing through holes in each of the component parts and the shaft prior to liquid phase sintering, and passing positioning pins with oil holes through these through holes. However, in this method, a pin hole with a diameter larger than the pin diameter must be provided in the component part, taking into consideration the shrinkage rate due to liquid phase sintering of the powder sintered material that makes up the component part. Therefore, when a pin is passed through the pin hole provided in the component and the shaft, a gap is created between the pin hole of the component and the positioning pin, and during liquid phase sintering, the component is attached to the shaft by this gap. They were displaced and sometimes even fell off. Further, since the pin holes must be provided in the component parts and the shaft so as to be in line with each other, highly accurate machining is required, and therefore machining operations are difficult.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, an object of the present invention is to provide a temporary fixing structure for an assembled camshaft that can improve the positioning accuracy of components relative to the shaft.

According to the present invention, in the temporary fixing structure of an assembled camshaft in which component parts such as a cam lobe and a journal are integrally joined to the shaft by liquid phase sintering, the outer circumference of the shaft has a predetermined width in the axial direction. A groove is provided, and a recess with a semicircular cross section perpendicular to the groove is provided in the circumferential direction of the outer circumference of the shaft, and the inner circumference of the component is tightly fitted into the groove in the axial direction. A protrusion of a predetermined width is formed, and the protrusion is provided with a recess that traverses it at a midpoint of its length, the two recesses facing each other and cooperating with a portion of the inner circumferential surface of the component to form an empty space. an elastic member is disposed in the cavity, and the elastic member has a circumferential surface that engages with an inner surface of the two opposed recesses to prevent axial displacement of the component relative to the shaft; , characterized in that circumferential displacement of the component relative to the shaft is prevented by fitting the protrusion of the component into the groove of the shaft.

To illustrate the invention with reference to the drawings, FIGS. 1A and 1B show an assembled camshaft according to the invention, in which the shaft 2 fits into a hole 32 in the cam lobe 3. FIG.

As shown in FIGS. 2A, 2B, and 2C, a groove 5 having a predetermined width and a rectangular cross section
extends along the entire length of the shaft 2 at its outer periphery. Further, a plurality of recesses 21 are provided in the circumferential direction of the shaft 2, perpendicular to the groove 5, and spaced apart at predetermined intervals depending on the mounting positions of components such as cam lobes and journals. Each of the recesses 21 has a semicircular cross section and extends for a predetermined length in the circumferential direction of the shaft 2, so that each recess 21 and the groove 5 are perpendicular to each other. The depth of the recess 21 is determined by the elastic member 4 disposed within the recess 21.
It is preferable that the thickness be greater than the thickness of .

Similarly, as shown in FIGS. 3A and 3B,
A protrusion 6 having a width slightly smaller than the width of the groove 5 and having a rectangular cross section so as to fit snugly into the groove 5.
is formed in the axial direction of the cam lobe at a predetermined location on the inner circumference of the hole 32 of the cam lobe 3 that fits into the shaft. Further, a recess 61 is provided so as to cross the protrusion 6. Preferably, the recess 61 is provided in the middle of the length of the protrusion 6. This is because, in a sintered material shaped like a cam lobe, such an intermediate location is least susceptible to shrinkage during liquid phase sintering. The recess 61 has a triangular cross section.

As can be seen from FIG. 1B, the recess 21 of the shaft 2 and the recess 61 of the cam lobe 3 face each other at predetermined positions, and the edges 21A and 61A of the recess, and 21B and 61
When B are the same and the protrusion 6 of the cam lobe 3 is fitted into the groove 5 of the shaft 2,
The recesses 21, 61 and the circumferential surface 3A of the cam lobe constitute a cavity (see FIG. 1A).

As can be seen from FIGS. 1A, 1B, and 5, an elastic member 4 is arranged in the cavity 7 in the assembled camshaft 1, and the circumferential surface of the elastic member meets the inner surface of the recesses 21 and 61. A portion of the edge thereof is in contact with the inner surface 21C of the recess 21. Recess 21
The shaft 2
The axial displacement of the cam lobe 3 relative to the shaft 2 is prevented by the engagement of the circumferential surface of the elastic member 4 with the inner surface 21D of the recess 21 and the opposing slope 61C of the recess 61. Displacement is prevented.

Next, I will explain the temporary fixing procedure.
Arranging the elastic member 4 in the recess 21 of the shaft 2,
The elastic member is fixed by spot welding or adhesive, and the elastic member is compressed toward the center of the shaft 2 by a pushing guide blade (not shown) using a well-known method. As mentioned above, since the depth of the recess 21 is greater than the thickness of the elastic member 4, most of the compressed elastic member is in the recess 2.
1 and curves into a U shape as shown in Figure 4. Next, the protrusion 6 of the cam lobe 3 is fitted into the groove 5 of the shaft 2, and the cam lobe 3 is fitted onto the shaft.
Move it relative to the shaft. When the end face of the cam lobe 3 reaches the elastic member, the pushing guide blade is pulled out, and the cam lobe 3 is further moved relative to the shaft, so that the recess 21 of the shaft 2 and the recess 61 of the cam lobe 3 match. When both the recesses 21 and 61 match, the elastic member 4 restores its shape due to its elasticity and the protrusion 6
As described above, the circumferential surface of the elastic member engages with the inner surface of both recesses, temporarily fixing the shaft 2 and cam lobe 3 in a predetermined position (first A).
(See Figures 1B and 5).

Next, these are subjected to liquid phase sintering to integrate the cam lobe 3 and the shaft 2 to produce an assembled camshaft.

In the temporary fixing structure of the assembled camshaft according to the present invention, since the elastic member is surrounded by the shaft and the cam lobe in an engaged state, there is no risk of it falling off, and the positioning accuracy of the cam lobe with respect to the shaft is excellent. Therefore, it has the advantage that the cam lobe is not displaced relative to the shaft during liquid phase sintering.

In the embodiment of the present invention, the recess of the shaft 2 has a semicircular cross section, and the recess 6 of the protrusion 6 of the cam lobe 3
1 has a triangular cross section, but as a modification, these may be reversed. Further, the recesses provided in the shaft and the cam lobe may have any shape, and in this case, an elastic member having a shape corresponding to the space formed by the recesses is arranged.

Furthermore, in the present invention, the shaft and the cam lobe are provided with grooves and protrusions, respectively, but these may be reversed, or a plurality of grooves and protrusions may be provided.

Although the present invention employs a cam lobe as an example, it is clear that the present invention can also be applied to other components such as journals.

[Brief explanation of drawings]

FIG. 1A is a cross-sectional view of the temporary fixing structure of the assembled camshaft according to the present invention, and FIG.
FIG. 3 is a side sectional view taken along line A-A of the assembled camshaft shown in the figure. Figures 2A, 2B, and 2C are
A cross-sectional view of the shaft of the present invention, a side cross-sectional view of the shaft shown in FIG. 2A, taken along line B-B, respectively;
FIG. 3 is a plan view of the shaft. FIG. 3A is a cross-sectional view of the cam lobe of the present invention, and FIG. 3B is a side cross-sectional view of the cam lobe of FIG. 3A taken along line C--C. FIG. 4 is an enlarged detail view of the circled area D of the assembled camshaft shown in FIG. 1A, before the cam lobe and shaft recesses meet each other. FIG. 5 is an enlarged detail view of the circled area D of the assembled camshaft shown in FIG. 1A, showing the cam lobe and shaft recesses mating with each other. 1...Assembling camshaft, 2...shaft,
3...Cam lobe, 4...Elastic member, 5...Groove, 6
... protrusion, 7 ... void, 21, 61 ... recess.

Claims (1)

[Claims] 1. In a temporary fixing structure of an assembled camshaft in which component parts such as a cam lobe and a journal are integrally joined to a shaft by liquid phase sintering, the outer circumference of the shaft is provided with a predetermined width in the axial direction. A groove is provided, and a recess with a semicircular cross section perpendicular to the groove is provided in the circumferential direction of the outer circumference of the shaft, and the inner circumference of the component is tightly fitted into the groove in the axial direction. A protrusion of a predetermined width is formed, and the protrusion is provided with a recess that traverses it at a midpoint of its length, the two recesses facing each other and cooperating with a portion of the inner circumferential surface of the component to form an empty space. an elastic member is disposed in the cavity, and the elastic member has a circumferential surface that engages with an inner surface of the two opposed recesses to prevent axial displacement of the component relative to the shaft; A temporary fixing structure for an assembled camshaft, characterized in that circumferential displacement of a component with respect to the shaft is prevented by fitting a protrusion of the component into a groove of the shaft. 2. The recess of the protrusion of the component and the recess of the groove of the shaft each have a triangular cross section;
The temporary fixing structure for an assembled camshaft according to claim 1, characterized in that it has a semicircular shape.