JPH0526009A - Fixing structure of synthetic resin made member toward shaft - Google Patents

Abstract

PURPOSE:To prevent looseness from being generated between a cam gear and a cam shaft even under a high temperature, while assembling a synthetic resin made cam gear into the cam shaft easily. CONSTITUTION:A cam gear 2 and a plate 32 are piled in this order on the outward flange part 31 of a cam shaft 1. A taper shaped opening part 34 is provided on the side opposite to a side where the cam gear 2 of the rivet penetrating hole of the outward flange part 31, is piled and a taper shaped opening part 35 is provided on a side where the plate 32 of the rivet penetrating hole of the cam gear 2, is piled and furthermore a taper hole part 36 adapted to the taper surface of the opening part 35 is provided on the plate 32. Since only by piling each member, and guiding a rivet 33 through the pile and calking it, it becomes possible to combine the cam gear 2 with the cam shaft 1 easily, while preventing looseness along circumference direction without being influenced by heat-deformation of the cam gear 2 by engaging taper surfaces with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for fixing a synthetic resin member to a shaft.

[0002]

2. Description of the Related Art Gears used in a torque transmission mechanism include
For example, in some cases, a synthetic resin gear is used for the purpose of reducing noise. Conventionally, resin gears are attached to shafts by pressing synthetic resin gears directly into the shaft and fixing them with some sort of rotation-stopping structure, or by inserting metal bushes into synthetic resin gears and insert-molding them. There was one that pressed the bush into the shaft.

However, in the case where the synthetic resin gear is directly press-fitted, the inner diameter of the fitting hole for the shaft of the synthetic resin gear increases when the ambient temperature rises due to changes in the operating conditions. However, there is a problem that rattling occurs between the shaft and the shaft. Also, in the case of fixing via a metal bush, the metal bush and the synthetic resin gear must be centered and integrated with high precision with respect to each other, and processing work during insert molding is required. There was a problem of complication.

[0004]

In view of the above problems of the prior art, the main object of the present invention is that the assembly is easy and the gap between the shaft and the shaft is high even when used at high temperature. It is an object of the present invention to provide an improved structure for fixing a synthetic resin member to a shaft so as to prevent rattling.

[0005]

According to the present invention, a shaft made of a synthetic resin member of the type in which a synthetic resin member is integrally connected to a flange portion formed on the shaft by a rivet. In the fixing structure to, the metal plate is superposed on the side opposite to the flange portion side of the member, and the side of the member of the insertion hole of the rivet provided in the flange portion is superposed. A first tapered opening formed on opposite sides; a second tapered opening formed on a side of the insertion hole of the rivet provided in the member where the plate overlaps; A tapered hole portion that is recessed in the plate so that the rivet can be inserted therethrough, and the member is sandwiched between the flange portion and the plate; Rivet A shaft made of a synthetic resin member, characterized in that end portions are formed so as to respectively fit in the first tapered opening portion and the tapered hole portion, and the member is integrally coupled to the shaft. This is accomplished by providing a fixed structure.

[0006]

With this configuration, when a rivet is used, the tapered surface of the rivet head of the rivet conforms to either the first tapered opening or the tapered hole. Since the caulking part of the rivet is formed in a taper shape so as to fit to the other, it is possible to prevent rattling of the member with respect to the shaft in the circumferential direction by engagement of the tapered surfaces at both ends of the rivet You can Further, when the rivet is swaged, the rivet does not directly contact the synthetic resin member and the metal plate is interposed,
The stress concentration at the time of crimping can be dispersed by the plate, and the synthetic resin member can be fixed while being sandwiched between the flange portion of the shaft and the plate.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a side sectional view showing a governor mechanism of an engine to which the present invention is applied, and FIGS. 2 and 3 are sectional views of FIG.
It is the figure seen along the II-II line and the III-III line. This governor mechanism is, for example, a camshaft 1 of an OHV type engine.
It is provided in.

The camshaft 1 is rotatably pivotally mounted in a crankcase of an engine (not shown), and is geared to a crankshaft (not shown) via a synthetic resin member cam gear 2 fitted in an intermediate portion. There is. The cam gear 2 has both an outward flange portion 31 integrally formed in the intermediate portion of the cam shaft 1 and an annular metal plate 32 superposed on the side opposite to the outward flange portion 31 side of the cam gear 2. In the state of being sandwiched between them, they are integrally coupled to the camshaft 1 by rivets 33 inserted between the respective members.

Four cams for driving intake and exhaust valves for each cylinder are formed on the left axial end of the camshaft 1 in the axial direction in FIG. In this embodiment, one exhaust valve cam 3 is shown. When the camshaft 1 rotates with the rotation of the engine, the exhaust valve cam 3 causes the push rod 4 to reciprocate to push the push rod 4. Through the rod 4 and a rocker arm (not shown), the corresponding exhaust valve is driven to open / close at an appropriate timing. The other intake and exhaust valves are similarly controlled to be opened and closed.

The governor holder 5 and the governor slider 6 are provided on the other axial free end side of the cam gear 2 of the cam shaft 1.
And are provided coaxially. The governor holder 5 is made of a synthetic resin material, and as shown in FIG. 2, it is formed in a star shape having five radially outward arm portions 7 arranged at equal angular pitches. Assembled in 1. Each arm 7 is provided with a guide slot 7a extending in the radial direction. Each of the guide slots 7a is formed in a groove shape so as to receive the ball 8 as a governor weight and guide the ball 8 so as to be reciprocally movable in the radial direction. The guide slot 7a
A part of the bottom wall portion of the ball is open so that a part of the ball 8 can be exposed to the outside.

At the center of the governor holder 5, there is formed a fitting hole 5a to be fitted on the outer peripheral surface of the intermediate portion of the camshaft 1, and the fitting hole 5a of the governor holder 5 is divided into three equal parts in the circumferential direction. At each position, a tongue-shaped elastic engaging piece 9 formed so as to extend along the axial direction is provided. The free end portion of the elastic engagement piece 9 is formed with an engagement protrusion 9a that protrudes radially inward from the inner peripheral surface of the fitting hole 5a in a natural state.

A circumferential groove 11 is provided on the outer peripheral surface of the camshaft 1 at a position corresponding to the engaging projection 9a in the assembled state of the cam holder 5 to the camshaft 1, and the circumferential groove 11 is provided. The engagement protrusion 9a engages with the shaft 11 to prevent the governor holder 5 from coming off and being positioned with respect to the camshaft 1 in the axial direction. When the governor holder 5 is assembled to the camshaft 1, the governor holder 5 is moved to the assembled position.
Slide on the outer peripheral surface of the camshaft 1,
At that time, since the elastic engagement piece 9 bends and the engagement protrusion 9a can escape to the outside in the radial direction, the engagement protrusion 9a is assembled.
a does not get in the way.

Further, on the surface of the governor holder 5 on the cam gear 2 side, there is provided a cylindrical convex portion 13 projecting in the axial direction. The convex portion 13 is recessed in the engaging hole 14 provided at a corresponding position of the cam gear 2, and the convex portion 13 and the engaging hole 1
The governor holder 5 is prevented from rotating in the circumferential direction by the engagement with 4.

The above-mentioned governor slider 6 is a bush 6a as a slide bearing which is slidably fitted to the outer peripheral surface of the camshaft 1 along the axial direction, and is coaxially fitted to the outer peripheral portion of the bush 6a. It is composed of a dish-shaped flange portion 6b. A retaining ring 15 is provided at the right end portion of the outer peripheral surface of the camshaft 1 on which the governor slider 6 is fitted in FIG.
Is attached so that the governor slider 6 can reciprocate between the governor holder 5 and the retaining ring 15. The governor slider 6 is assembled so that the inside of the dish-shaped flange portion 6b faces the governor holder 5 side so as to cover the ball 8 described above.
Therefore, the inclined surface portion on the edge side of the flange portion 6b engages with the ball 8, and the ball 8 can move between the solid line and the imaginary line shown in FIG.

A part of the bush 6a of the governor slider 6 is
The flange portion 6b is formed in a radially outward flange shape for positioning, and the outward flange portion is swingable on the crankcase so as to transmit the movement amount of the governor slider 6 to a throttle valve (not shown). The free end of the supported governor arm 16 is resiliently impacted. The governor arm 16 is spring-biased by its free end in such a direction as to push the governor slider 6 back to the governor holder 5 side.

Therefore, before the engine is started, the centrifugal force acting on the ball 8 is small because no centrifugal force is generated, so that the ball 8 is radially innermost in the guide slot 7a as shown by the solid line in FIG. It is elastically pushed back by the governor slider 6 so as to be located at the end. On the other hand, when rotating, a centrifugal force is generated, so that the ball 8 moves outward in the radial direction of the guide slot 7a as shown by an imaginary line in FIG. 1, and the governor slider 6 by the centrifugal force is moved.
The governor slider 6 is held at a position where the pushing force to the governor arm 16 and the biasing force from the governor arm 16 side to the governor slider 6 are balanced. The engine is kept at a constant speed according to the displacement of the governor arm 16 in that state.

By the way, a pivot pin 17 oriented along the axial direction is fixed to the left end face of the cam gear 2 in FIG. 1, as also shown in FIG. A base end of a plate-shaped weight 18 formed in a C shape is pivotally supported in the direction of the end of the cam gear 2. The weight 18 is provided so as to substantially surround the cam shaft 1 in the circumferential direction. Further, an axial hole 1a is coaxially bored in the camshaft 1, and a part of the axial hole 1a is axially supported by a reduced diameter portion on the inner side of the axial hole 1a. Decompression shaft 19
Are coaxially and rotatably received. In the middle portion of the decompression shaft 19, a circumferential groove 1 having a substantially semicircular cross section is formed.
9a is formed over the entire circumference, and the decompression rod 2 is reciprocally received in the camshaft 1 so that the axial directions of the decompression shaft 19 are orthogonal to each other.
1 is provided so that a part of the outer peripheral surface of the intermediate portion thereof is received in the circumferential groove 19a. As described above, the decompression shaft 19 and the decompression rod 21 are provided so as to partially overlap with each other and be orthogonal to each other.

FIG. 4 and FIG. 1 showing an enlarged main part of FIG.
5, which is an enlarged cross-sectional view of an essential portion corresponding to FIG. 5, the slit-shaped axial line cut along the axial direction so as to cross the circumferential groove 19a on the outer peripheral portion of the decompression shaft 19. A direction groove 19b is formed, and an engagement pin 22 is received in the groove 19a. A slit-shaped radial groove 21a cut in a direction orthogonal to the axis of the decompression rod 21 is formed at a portion of the decompression rod 21 that intersects with the decompression shaft 19, and an intermediate portion of the engaging pin 22 is formed. The engagement pin 22 is received in the radial groove 21 a, and both ends of the engagement pin 22 in the axial direction are received in the axial groove 19 b of the decompression shaft 19.
Through the engagement pin 22, the decompression rod 21 is engaged with each other so that the decompression rod 21 is displaced in the axial direction in response to the rotation of the decompression shaft 19.

As shown clearly in FIG. 3, the decompression rod 21 is formed to be somewhat longer than the outer diameter of the corresponding portion of the camshaft 1. On both axial end faces of the decompression rod 21, an intermediate engaging portion formed by cutting and raising at an intermediate portion of the weight 18 and a weight 18 of the weight 18 are provided so as to face each other with the intermediate engaging portion sandwiching the decompression rod 21. The free end engaging portions formed by cutting and raising the free ends are in contact with each other. Therefore, the decompression rod 21 reciprocates according to the swing motion of the weight 18, and the decompression shaft 19 rotates via the engagement pin 22.

The weight 18 is rotated by the rotation of the camshaft 1.
A centrifugal force acts on the weight 18, and the centrifugal force causes the weight 18 to swing so as to displace the free end portion radially outward.
As shown in FIG. 3, the weight 18 is provided on the side opposite to the governor holder 5 side of the cam gear 2 in order to urge the weight 18 with a predetermined spring force in a direction against the swinging force of the centrifugal force. A return spring 23 having a base end supported by a pin 20 fixed to the end face in an upright state is connected.

The axial end portion of the axial support portion of the decompression shaft 19 extends to a position corresponding to the exhaust valve cam 3 and other exhaust valve cams (not shown). Further, in a portion of the cam shaft 1 adjacent to the exhaust valve cam 3, as shown in FIG. 6, a guide hole radially extending between the outer peripheral surface of the cam shaft 1 and the axial hole 1a. 24 is drilled. In the guide hole 24, a decompression pin 25 is supported so as to be reciprocally movable.
The head portion 5 is adapted to be able to project and retract with respect to the outer peripheral surface of the camshaft 1.

On the projecting side of the decompression pin 25, a shoulder 25a is formed by cutting off a part of the projecting end, and the camshaft 1 has a shoulder 25a when the decompression pin 25 is assembled. Circumferential groove 1 passing through
b is formed, and a C-shaped spring 26 formed of a leaf spring material is assembled in the circumferential groove 1b with its own elastic force. A part of the C-shaped spring 26 is adapted to engage with the shoulder portion 25a of the decompression pin 25,
The decompression pin 25 is retained so as to be elastically pushed back into the camshaft 1.

The portion of the decompression shaft 19 that abuts on the decompression pin 25 is D as shown in FIG.
It is formed in a V-shaped cross section. This FIG. 6 corresponds to the state shown by the solid line in FIG. 4, and is the state before the engine is started. As shown in FIG. 7, before starting, the base end surface 25b of the decompression pin 25 contacts the circular arc surface of the decompression shaft 19, and the C-shaped spring 26
The decompression pin 25 projects from the outer peripheral surface of the camshaft 1 against the urging force of. In this projecting state, the projecting end of the decompression pin 25 projects further outward in the radial direction than the base circle of the exhaust valve cam 3, so that the exhaust valve is always open. The engine rotates and centrifugal force causes
When the weight 18 swings in the direction of arrow A, which is the counterclockwise direction in FIG. 7, the state shown by the imaginary line in FIG. 4 is reached, and the decompression shaft 19 rotates to the position shown in FIG. 7. At this time, the base end surface 25 of the decompression pin 25 is attached to the flat surface 19c of the D-shaped cross section of the decompression shaft 19.
b comes into contact, and the decompression pin 25 is pushed back by the urging force of the C-shaped spring 26. In this retracted state, the push rod 4 comes into sliding contact with the cam surface of the exhaust valve cam 3, and normal on-off valve control is performed.

Between the cam gear 2 and the governor holder 5, an annular bottom plate 27 is movably received in a circumferential direction in an annular recessed portion provided on the end face of the cam gear 2 on the governor holder 5 side. Has been done. As described above, the ball 8 is in contact with the bottom plate 27 via the opening of the guide slot 7a of the governor holder 5, and the ball 8 may directly contact the cam gear 2 made of synthetic resin in this embodiment. It is possible to prevent the cam gear 2 from being worn by the movement of the ball 8.

By the way, as described above, the cam gear 2
Is riveted in a state of being sandwiched between the outward flange portion 31 and the plate 32, but the axis line of the rivet 33 inserted from the outward flange portion 31 side is the direction along the axis line of the camshaft 1. That is, the direction is orthogonal to the rotation direction. Further, an opening 34, which is a first tapered opening on the side of the rivet insertion hole of the outward flange 31 opposite to the cam gear 2 side, is formed in a tapered shape that expands in the direction opposite to the insertion direction of the rivet 33. ing. Therefore, by using, for example, a rivet as the rivet 33,
The tapered surface formed on the head of the rivet 33 and the tapered surface of the opening 34 are engaged with each other.

Plate 3 of rivet insertion hole of cam gear 2
An opening 35, which serves as a second tapered opening on the side where 2 is overlapped, is formed in a tapered shape that widens in the insertion direction of the rivet 33. Further, a portion corresponding to the opening portion 35 of the plate 32, which is superposed in close contact with the end surface of the cam gear 2 opposite to the outward flange portion 31 side, has a hole through which the rivet 33 can be inserted and has an opening. Part 3
5. Tapered hole 3 formed to fit the tapered surface of 5
6 is provided. Therefore, after inserting the rivet 33, by caulking the insertion direction end of the rivet 33 which is exposed to the outside from the insertion hole of the taper hole 36, the rivet 33 is inserted so as to fit into the taper hole 36. A taper surface is formed at the end in the direction, and the outward flange portion 31, the cam gear 2, and the plate 32 are integrally connected to each other.

In the state where the rivet 33 is coupled in this way, the tapered surface of the head of the rivet 33 and the tapered surface of the opening 34 of the outward flange portion 31 are brought into surface contact with each other to engage with each other. It is possible to prevent rattling in the circumferential direction around the axis of the camshaft 1 between the outward flange portion 31 and the rivet 33. Further, the tapered surface of the opening 35 of the cam gear 2 and the tapered surface of the tapered hole 36 of the plate 32 on the convex side are in surface contact with each other, and are engaged with each other.
Moreover, since the concave tapered surface of the tapered hole portion 36 of the plate 32 and the tapered surface of the caulking portion of the rivet 33 are in surface contact with each other and engage with each other, rattling of the cam gear 2 with respect to the rivet 33 in the circumferential direction can be prevented. ..

In this way, the cam gear 2 is riveted via the metal plate 32, and the rivet 33 is not caulked directly to the cam gear 2 made of synthetic resin. The cam gears 2 made of synthetic resin can be suitably riveted because they are dispersed by the contact surfaces. In this example,
Further, although the rivet 33 is inserted from the outward flange portion 31 side and the plate 32 side of the rivet 33 is caulked, it may be inserted in the opposite direction and caulked on the outward flange portion 31 side.

[0030]

As described above, according to the present invention, the play in the circumferential direction of the synthetic resin member with respect to the shaft is secured by the engagement of the tapered surface between the flange portion and the rivet, and the member and the metal plate. By the engagement of the tapered surface of the rivet, it can be preferably prevented, and since the member is riveted through the metal plate, the stress concentration on the synthetic resin member due to the caulking of the rivet can be prevented, The member may suitably be integrally connected to the shaft.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a main part of a governor mechanism to which the present invention is applied.

FIG. 2 is a view taken along line II-II in FIG.

FIG. 3 is a view taken along line III-III in FIG.

FIG. 4 is an enlarged view of a main part of FIG.

5 is an enlarged view corresponding to the main part of FIG. 1. FIG.

6 is a view taken along line VI-VI in FIG. 1. FIG.

FIG. 7 is a view corresponding to FIG. 6 in an engine rotating state.

[Explanation of symbols]

 1 Camshaft 1a Axial hole 1b Circumferential groove 2 Cam gear 3 Cam 4 Push rod 5 Governor holder 6 Governor slider 6a Bushing 6b Flange part 7 Arm part 7a Guide slot 8 Ball 9 Elastic engaging piece 9a Engaging convex part 11 Circumferential groove 12 recessed part 13 convex part 14 engagement hole 15 retaining ring 16 governor arm 17 pivot pin 18 weight 19 decompression shaft 19a circumferential groove 19b axial groove 19c flat surface 21 engagement pin 22 decompression rod 22a groove 23 return spring 24 Guide hole 25 Decompression pin 25a Shoulder portion 25b Base end face 26 C-shaped spring 27 Bottom plate 31 Outward flange portion 32 Plate 33 Rivet 34 Opening portion 35 Opening portion 36 Taper hole portion

Claims (1)

Claim: What is claimed is: 1. A structure for fixing a synthetic resin member to a shaft, wherein the synthetic resin member is integrally joined to a flange portion formed on the shaft by a rivet. The metal plate is superposed on the side opposite to the flange portion side, and the first side is formed on the side opposite to the side where the member of the insertion hole of the rivet provided in the flange portion is superposed. A tapered opening, a second tapered opening formed on a side of the insertion hole of the rivet provided in the member that overlaps the plate, and the second opening
And a taper hole portion which is recessed in the plate so that the rivet can be inserted therethrough, and the member is sandwiched between the flange portion and the plate to form the rivet. To the shaft of a synthetic resin member, characterized in that both ends of the member are formed so as to respectively match the first tapered opening and the tapered hole, and the member is integrally connected to the shaft. Fixed structure.