JPS62130725A - Production of hollow assembly cam shaft - Google Patents

Abstract

PURPOSE:To prevent the force higher than the allowable stress working and to prevent deformation and breakage by interposing the buffer consisting of the soft material having sufficient elongation between a pipe and a cam or a journal, etc. CONSTITUTION:The unevenness 4 of a triangular tooth serration shape or the unevenness of knurling shape is formed on the inner peripheral face of the cam 2 and journal, etc., consisting of the wear resistant material which is fitted to the outer peripheral face of the pipe 1 of a hollow assembly cam shaft and the pipe 1. The unevenness of a triangular tooth serration shape of the buffer 6 consisting of the soft material annularly formed is interposed between the pipe 1 and cam 2 or journal, etc. And when the unevenness of the pipe 1 is fitted to the unevenness of the cam 2 and journal by expanding the pipe 1, the buffer 6 is combined as well by following the change thereof and the deformation and breakage of the cam 2 and journal are prevented as well as the sufficient combining strength.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a camshaft for an internal combustion engine, and more particularly to members such as cams and journals made of steel pipes and wear-resistant materials for hollow assembled camshafts. This relates to the method of combining with.

Conventional technology and problems How to manufacture camshafts for internal combustion engines.

In response to the traditional methods of casting and hot forging, as well as recent demands for higher performance and lighter weight engines, hollow steel pipes are combined with parts such as cams and journals made of wear-resistant materials. There are assembled camshafts, etc.

Hollowing technology for cast camshafts is being established to reduce weight, but the material remains the same, so the cam surface of the sliding part, which requires wear resistance, is hardened by quenching or chilling. There are layers. In addition, it is difficult to make a camshaft made by hot forging hollow due to manufacturing technology, there is no established technology, and it is difficult to reduce the weight of the camshaft. For example, at present, a hardened layer is provided by induction hardening or the like.

In addition, for hollow assembled camshafts, the method of joining sliding members such as cams and journals made of pipes made of steel with excellent strength and sintered alloys with excellent wear resistance is not possible using conventional casting or hot forging. There are several joining methods, such as brazing, liquid phase sintering, and pipe expansion joining methods, which have the advantage of being lighter and more wear resistant than conventional methods. There are also pros and cons.

If a heat treatment process is involved during joining, the pipes will bend significantly due to thermal distortion, and the camshaft has poor machinability, so it will be necessary to increase the final polishing method, resulting in a decrease in productivity.

Also, in the pipe expansion and connection method, in order to firmly attach parts such as cams to the pipe, it is necessary to expand the pipe by a rate of 5% or more, and for this reason, the hole diameter of the cam etc. has to be expanded by a few percent. Therefore, when using sintered alloys or ceramics with low elongation as cams and journals, the appropriate If the pipe expansion ratio is not correct, there is a problem in that a force exceeding the allowable stress acts on components such as cams, causing deformation and cracking.

Means for Solving the Problems The present invention has been made in view of these conventional problems, and provides a joining method that prevents deformation and cracking of cams, journals, etc. in the pipe expansion joining method. By interposing a cushioning material made of a soft material with sufficient elongation between the pipe and the cam, journal, etc., the expansion force of the pipe does not directly apply to the cam, journal, etc.

This prevents a force exceeding the allowable stress from acting on the cam or journal, thereby preventing deformation or damage to the cam or journal.

The cushioning material made of a soft material inserted between the pipe constituting the hollow assembled camshaft of the present invention and parts such as cams and journals is made of, for example, copper, copper alloy, aluminum alloy, resin, etc. It is formed in the shape of an annular body or a ring with serration-like unevenness.

In order to prevent the coupling force between the pipe and the cam, journal, etc. from decreasing by interposing a buffer material and increase the coupling force, and to prevent the rotation of the cam and determine the phase of the cam, the outer surface of the pipe is and engraved on the inner peripheral surface of the hole of the cam or journal. By inserting a cam or journal into a pipe that has irregularities in the form of triangular tooth serrations or knurled grooves, and expanding the pipe by inserting the soft material into the voids of each irregularity, the pipe and the cam or journal can be It is something that is combined.

As a result, the expansion force of the pipe does not directly affect the cam and journal parts, and the soft material acts as a buffer zone, which elastically deforms and prevents the generation of localized high stress areas, resulting in wear resistance with low elongation. By not exceeding the allowable stress of cams, journals, etc. made of the material, and by meshing the concavities and convexities of the pipe with the cams and journals, it is possible to firmly connect them even if the expansion rate is small, preventing deformation or damage. Things will disappear.

In order to prevent insufficient coupling between the pipe and the cam or journal due to the presence of the cushioning material, it is necessary to appropriately select the shape and size of the unevenness, the rigidity of the cushioning material, the shape and dimensions, etc.

Example Embodiments of the present invention will be described based on the drawings.

As shown in Fig. 1, the outer peripheral surface of the pipe 1 of the hollow assembled camshaft has a triangular shape in order to increase the bonding force with the cushioning material, prevent the rotation of the cam and journal, or determine the phase of the cam. The tooth serration-shaped unevenness 4 or the knurled groove unevenness 5 extends along the entire length of the pipe, or as shown in FIGS. 8 and 9, the cam position 1! (a) and ja-naru localization II
(b). This pipe has a cam 2 and a journal 3 having triangular serration-shaped unevenness 4 or knurled groove unevenness 5 on the inner peripheral surface that fits into the unevenness of the pipe 1 as shown in FIG. After inserting the cushioning material 6 made of a soft material having a triangular tooth serration shape or a ring shape as shown in FIG. 4 and FIG. As shown in FIG. 7, the unevenness of the pipe 1 bites into the unevenness of the cam 2 and journal 3, and at that time, the buffer material 6 follows the change and is bonded, so that the cam 2 and the journal 3 have sufficient bonding strength. There was no longer any deformation or damage to the journal 3.

Furthermore, in order to interpose the buffer material 6, an appropriate gap is formed between the pipe 1 and the cam 2 and journal 3, but even if there is a slight difference in the gap, the buffer material 6 should be able to sufficiently accommodate the difference. Compared to the case where a member such as a cam is directly inserted into and connected to a pipe, which requires high processing accuracy, processing becomes easier because processing accuracy is not required as much.

Effect according to the present invention. When connecting a cam, journal, etc. to a pipe in a hollow assembled camshaft, it is necessary to create unevenness to increase the bonding force between the pipe and the cam, journal, etc., and to prevent rotation of the cam or determine the phase of the cam. By providing grooves and interposing a buffer material between these pipes and the cams and journals, expanding the pipes and connecting them, the cams and journals will not be deformed or damaged, and an excellent connection can be easily obtained. The industrial effects are significant.

[Brief explanation of drawings]

Fig. 1 A perspective view of a pipe having irregularities in the shape of triangular tooth serrations. Fig. 2 A perspective view of a cam having irregularities in the shape of triangular tooth serrations. Figure 3 A perspective view of a cushioning material formed with irregularities in the shape of triangular tooth serrations. Figure 4: A schematic partial external view of a pipe with a cam and journal connected to it Figure 5: A sectional view taken along line A-A in Figure 4 Figure 6: An enlarged view of part B in Figure 5 Figure 7: an enlarged view of part C in Figure 6 Figure 9 External view of a pipe with triangular tooth serrations in the fixed positions of the cam and journal Figure 9 External view of a pipe with knurling-shaped unevenness in the fixed positions of the cam and journal 1 = Pipe 2: Cam 3: Journal 4: Triangular Tooth serration-shaped unevenness 5: Knurling-like unevenness 6: Cushioning material

Claims (1)

[Claims] Triangular tooth serration-shaped irregularities are formed on the outer circumferential surface of the steel pipe (1) and the inner circumferential surface of the cam (2), journal (3), etc. made of wear-resistant material that fits on the outer circumferential surface of the steel pipe (1). (4) Or, in addition to forming knurling-like unevenness (5), the steel pipe (1), cam (2), or journal (3)
A cushioning material (6) made of a soft material formed in the triangular tooth serration shape or ring shape between the members.
A method for producing a hollow assembled camshaft, which comprises connecting a cam (2), a journal (3), etc. to a steel pipe (1) by expanding the steel pipe (1) with the intervening.