JPH0526070A - Governor mechanism - Google Patents

Abstract

PURPOSE:To easily integrate a governor holder into a cam shaft by engaging a protruding part with an engagement hole to prevent rotation, and engaging the engagement protruding part of an elastic engagement piece with a circumferential groove to prevent slippage. CONSTITUTION:An elastic engagement piece 9 elastically deformable in the radial direction is provided on the inner circumferential surface part of the fitting hole 5a of a governor holder 5, and an engagement protruding part 9a is formed on the free end part of the elastic engaging piece 9. A circumferential groove 11 is provided on the part corresponding to the integrating position of the governor holder 5 on the outer circumferential surface of a cam shaft 1. A protruding part 13 axially protruding is provided on the surface on a cam gear 2 side of the governor holder 5, and an engagement hole 14 is provided in the position corresponding thereto of the cam gear 2. The governor holder 5 is fitted to the cam shaft 1, and moved on the cam gear 2 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a governor mechanism for controlling a rotation speed of an engine, and more particularly to a governor mechanism using a ball as a governor weight.

[0002]

2. Description of the Related Art In an engine used for a pump, a generator, a lawn mower, or the like, in order to maintain a constant rotation speed, for example, as disclosed in Japanese Patent Laid-Open No. 2-221645. Some are equipped with a centrifugal governor mechanism. Such a centrifugal type governor mechanism is rotatably supported by the engine body and is driven by a crankshaft or the like via a transmission mechanism.The governor holder is pivotally attached by a pin to the governor holder to correspond to the rotation speed of the engine. And a governor weight that expands in the centrifugal direction, and a central portion of the governor holder that is slidably fitted to a shaft that projects in the axial direction, and reciprocates by contacting an arm portion formed on the governor weight. The governor slider thus configured and the governor arm that transmits the movement amount of the governor slider to the throttle valve are provided.

However, in the centrifugal type governor mechanism as described above, there is a problem that the structure in which the governor weight is pivotally supported by the pin as described above is complicated and the assembly becomes complicated.

[0004]

SUMMARY OF THE INVENTION In view of the problems of the prior art as described above, a main object of the present invention is to provide a governor mechanism having a simple structure and easy assembling.

[0005]

According to the present invention, such a purpose is fitted on a shaft which rotates with engine rotation, and a ball as a governor weight can reciprocate in the radial direction of the shaft. Of the governor holder, a governor slider provided to engage with the ball so as to be displaceable in the axial direction according to the radial movement of the ball, and a governor holder by a centrifugal force acting on the ball. Means for elastically urging the governor slider in a direction against the axial displacement force; an outward flange portion provided on a side of the shaft opposite to the ball guide side of the governor holder; the governor holder and the One of the outward flanges is provided with an engaging projection that is provided to project in the axial direction, and the governor holder is rotated by engaging with the engaging projection. An engaging recess provided in the other one of the governor holder and the outward flange portion for stopping, an elastic engaging piece provided in the inner peripheral surface of the governor holder so as to be elastically deformable in the radial direction, and the elastic engaging member. It is achieved by providing a governor mechanism having a locking portion provided on an outer peripheral surface of the shaft so as to prevent the governor holder from coming off by engaging with a joint piece.

[0006]

By doing so, the centrifugal force acting on the ball is changed by the shaft that rotates as the engine rotates,
Since the ball can be moved in the radial direction of the shaft by being guided by the governor holder, the rotational speed is kept constant where the centrifugal force of the ball and the biasing force of the governor slider balance. When assembling the governor holder on the shaft, the governor holder is fitted on the shaft, and the outward flange portion of the shaft and the engaging convex portion and the engaging concave portion provided on the governor holder are engaged to prevent rotation. It is possible to fix the governor holder to the shaft by engaging an elastic locking piece provided on the inner peripheral surface of the governor holder with the locking portion on the outer peripheral surface of the shaft to prevent it from coming off.

[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 of the present invention, and FIGS.
FIG. 3 is a view taken along line II-II and line III-III in FIG. 1. This governor mechanism is provided, for example, on the camshaft 1 of an OHV engine.

The camshaft 1 is rotatably pivotally mounted in a crankcase of an engine (not shown), and a camshaft 2 and a gear (not shown) are coaxially fixed to an intermediate portion via a cam gear 2 as an outward flange portion. Are combined. 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.

A governor holder 5 and a 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 inner peripheral surface of the fitting hole 5a of the governor holder 5 is arranged in the circumferential direction. A tongue-shaped elastic engaging piece 9 is provided at each of the three divided positions so as to be elastically deformable in the radial direction by being formed so as to extend along the axial direction. ing. 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.

On the outer peripheral surface of the cam shaft 1, at the position corresponding to the engaging convex portion 9a in the assembled state of the cam holder 5 to the cam shaft 1, the circumferential groove 1 as a locking portion is formed.
1 is provided, and the engaging projection 9a is engaged with the circumferential groove 11 to prevent the governor holder 5 from axially slipping out and being positioned with respect to the camshaft 1. When the governor holder 5 is assembled to the camshaft 1, the governor holder 5 is assembled so as to slide axially on the outer peripheral surface of the camshaft 1 to the assembled position. Since the elastic engagement piece 9 can be bent so as to escape outward in the direction, the engagement protrusion 9a does not become an obstacle during assembly.

As shown in FIG. 4, the surface of the governor holder 5 on the cam gear 2 side is provided with a protrusion 13 as a cylindrical engagement protrusion that protrudes in the axial direction. The convex portion 13 is recessed in an engaging hole 14 as an engaging concave portion provided at a corresponding position of the cam gear 2, and the engagement between the convex portion 13 and the engaging hole 14 causes the governor holder 5 to rotate in the circumferential direction. Will be stopped.

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, centrifugal force is not generated in the ball 8, so that the ball 8 is positioned at the innermost end in the radial direction of the guide slot 7a as shown by the solid line in FIG. It is elastically pushed back by the governor slider 6. On the other hand, during rotation, a centrifugal force is generated, so that the ball 8 moves outward in the radial direction of the guide slot 7a as shown by the imaginary line in FIG. 1, and the centrifugal force pushes the governor slider 6 against the governor slider 6 and the governor arm. The governor slider 6 is held at a position where the urging force from the 16 side to the governor slider 6 is balanced. The engine is kept at a constant speed according to the displacement of the governor arm 16 in that state.

In this way, the governor mechanism using the ball weight is constructed. The governor holder 5 for guiding the ball 8 has the engaging projection 9 as described above.
a is engaged with the circumferential groove 11 to prevent it from coming off in the axial direction, and is engaged with the camshaft 1 by being prevented from rotating in the circumferential direction by the engagement of the protrusion 13 and the engaging hole 14. There is. When assembling the governor holder 5, the cam gear 2 is fixed to the cam shaft 1 in advance, the governor holder 5 is fitted from the right shaft end side of the cam shaft 1 in FIG. 1, and the convex portion 13 is formed into the concave portion. This is done by pushing the governor holder 5 while aligning it with the protrusion 14 to immerse the protrusion 13 in the recess 14, and elastically engage the engagement protrusion 9a with the circumferential groove 11. In this way, the governor holder 5 can be easily assembled.

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. 5 and FIG. 1 showing an enlarged main part of FIG.
As shown in FIG. 6 which is an enlarged cross-sectional view of an essential portion corresponding to FIG. 6, a slit-shaped axial line cut along the axial direction so as to traverse the circumferential groove 19a is formed 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 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 rotation of the camshaft 1 causes the weight 18
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 connected with a return spring 23 that biases the weight 18 with a predetermined spring force in a direction against the swinging force of the centrifugal force. The pin 20 that supports the base end of the return spring 23 is fixed to the end surface of the cam gear 2 opposite to the governor holder 5 side in an upright state, but the support hole for mounting the pin 20 is It is formed coaxially with the engaging hole 14 described above.

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 camshaft 1 adjacent to the exhaust valve cam 3, as shown in FIG. 7, a guide hole radially extending between the outer peripheral surface of the camshaft 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 in the circumferential direction 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 the decompression pin 25 is D as shown in FIG.
It is formed in a V-shaped cross section. FIG. 7 corresponds to the state shown by the solid line in FIG. 5, and is a 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 against the urging force of the C-shaped spring 26. The decompression pin 25 projects from the outer peripheral surface of the. 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. When the engine speed increases and the weight 18 swings in the direction of arrow A, which is the counterclockwise direction in FIG. 5, due to centrifugal force, the state shown by the imaginary line in FIG. Rotate to the position shown in 8. At this time, the base end surface 2 of the decompression pin 25 is attached to the flat surface 19c of the D-shaped cross section of the decompression shaft 19.
5b comes into contact with each other, 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.

[0025]

As described above, according to the present invention, the governor mechanism can be simply constructed by using the ball and the governor holder, and by moving the governor holder in the axial direction while fitting it on the shaft. , The governor holder is prevented from rotating by the engagement of the engaging concave portion and the engaging convex portion with the outward flange portion of the shaft, and the elastic engaging piece and the engaging portion are engaged with the outer peripheral surface of the shaft. Can be prevented from coming off, and the governor holder can be easily assembled.

[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 a view taken along line IV-IV in FIG.

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

FIG. 6 is an enlarged view corresponding to the main part of FIG.

FIG. 7 is a view taken along line VII-VII in FIG.

FIG. 8 is a diagram corresponding to FIG. 7 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 decompression rod 22 engagement pin 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

Claims (1)

Claim: What is claimed is: 1. A governor holder fitted to a shaft that rotates as an engine rotates, and which guides a ball as a governor weight so as to be reciprocally movable in a radial direction of the shaft; A governor slider provided to engage with the ball so as to be displaceable in the axial direction in response to a radial movement, and a direction against the axial displacement force of the governor holder due to a centrifugal force acting on the ball. A means for elastically urging the governor slider, an outward flange portion provided on a side of the shaft opposite to the ball guide side of the governor holder, and an axis line on one of the governor holder and the outward flange portion. Direction and the engaging convex portion, and the governor holder for engaging with the engaging convex portion to prevent the governor holder from rotating. An engaging concave portion provided on the other of the outward flange portion, an elastic engaging piece provided on the inner peripheral surface of the governor holder so as to be elastically deformable in the radial direction, and engaging with the elastic engaging piece. And a locking portion provided on the outer peripheral surface of the shaft to prevent the governor holder from coming off.