JP2901391B2 - Governor mechanism - Google Patents

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 the 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 keep the rotation speed constant, for example, as disclosed in Japanese Patent Application Laid-Open No. 2-221645. Some are provided with a centrifugal governor mechanism. Such a centrifugal governor mechanism is rotatably supported by the engine main body and is rotatably supported by a crankshaft or the like via a transmission mechanism, and is pivotally attached to the governor holder by a pin to correspond to the rotation speed of the engine. A governor weight that expands in the centrifugal direction, and is slidably fitted on a shaft that protrudes in the axial direction at the center of the governor holder, and reciprocates by contacting an arm portion formed on the governor weight. And a governor arm for transmitting the amount of movement of the governor slider to the throttle valve.

However, such a centrifugal governor mechanism as described above has a problem in that the structure for pivotally supporting the governor weight with the pins is complicated as described above, and assembly is complicated.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is a main object of the present invention to provide a governor mechanism which can simplify the structure and can be easily assembled.

[0005]

According to the present invention, there is provided, according to the present invention, a ball which is fitted on a shaft which rotates with the rotation of an engine, and which can reciprocate a ball as a governor weight in a radial direction of the shaft. A governor holder that guides the ball, 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 that is centrifugally acting on the ball. Means for resiliently biasing 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 An engagement protrusion that is provided on one of the outward flanges in the axial direction, and engages with the engagement protrusion to rotate the governor holder. An engagement recess provided on one of the governor holder and the outward flange portion to stop, an elastic engagement piece provided on an inner peripheral surface of the governor holder so as to be elastically deformable in a radial direction, This is achieved by providing a governor mechanism comprising: a locking portion provided on an outer peripheral surface of the shaft so as to engage with the mating piece to prevent the governor holder from coming off.

[0006]

In this way, the centrifugal force acting on the ball changes due to the shaft rotating with the rotation of the engine,
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 urging force of the governor slider are balanced. When assembling the governor holder to the shaft, the governor holder is fitted on the shaft, and the outwardly projecting 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, The governor holder can be fixed to the shaft by engaging an elastic retaining piece provided on the inner peripheral surface of the governor holder with the retaining portion on the outer peripheral surface of the shaft to prevent the governor holder from coming off.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a preferred embodiment of the present invention. FIG. 1 is a side sectional view showing a governor mechanism of an engine to which the present invention is applied, and FIGS.
FIG. 2 is a diagram viewed along the line II-II and III-III in FIG. 1. This governor mechanism is provided, for example, on a camshaft 1 of an OHV engine.

The camshaft 1 is rotatably mounted in a crankcase of an engine (not shown), and is connected to a crankshaft (not shown) through a cam gear 2 as an outward flange coaxially fixed to an intermediate portion. Are combined. For example, four cams for driving the intake and exhaust valves for each cylinder are formed on the left free end side in the axial direction of the camshaft 1 in FIG. In this embodiment, one exhaust valve cam 3 is shown, and when the camshaft 1 rotates with the rotation of the engine, the push rod 4 is reciprocated by the exhaust valve cam 3 and the push rod 4 is pushed. The corresponding exhaust valve is opened and closed at an appropriate timing through the rod 4 and a rocker arm (not shown). The other intake / exhaust valves are similarly opened and closed.

A governor holder 5 and a governor slider 6 are provided on the other axially free end side of the cam gear 2 of the camshaft 1.
Are provided coaxially. The governor holder 5 is made of a synthetic resin material and, as shown in FIG. 2, is formed in a star shape having five radially outwardly extending arms 7 disposed at an equal angular pitch. 1 is assembled. 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 to guide it reciprocally in the radial direction while receiving the ball 8 as a governor weight. The guide slot 7a
Is open so that a portion of the ball 8 can face outward.

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 extends in the circumferential direction. Each of the three equally divided positions is provided with a tongue-shaped elastic engaging piece 9 which is formed so as to extend along the axial direction so that it can be elastically deformed in the radial direction. ing. At the free end of the elastic engaging piece 9, an engaging convex portion 9a is formed which protrudes radially inward from the inner peripheral surface of the fitting hole 5a in a natural state.

On the outer peripheral surface of the camshaft 1, a circumferential groove 1 as an engaging portion is provided at a position corresponding to the engaging projection 9 a when the cam holder 5 is assembled to the camshaft 1.
The governor holder 5 is prevented from coming off in the axial direction and positioned with respect to the camshaft 1 by engaging the engaging projection 9 a with the circumferential groove 11. When assembling the governor holder 5 to the camshaft 1, the governor holder 5 is assembled so as to slide in the axial direction on the outer peripheral surface of the camshaft 1 to the assembling position. Since the elastic engaging pieces 9 can be bent so as to escape to the outside in the direction, the engaging convex portions 9a do not hinder the assembly.

On the surface of the governor holder 5 on the side of the cam gear 2, there is provided a projection 13 as a columnar engagement projection projecting in the axial direction as shown in FIG. The convex portion 13 is immersed in an engaging hole 14 as an engaging concave portion provided at a position corresponding to the cam gear 2, and the governor holder 5 rotates in the circumferential direction by the engagement between the convex portion 13 and the engaging hole 14. Be stopped.

The governor slider 6 has a bush 6a as a slide bearing which is slidably fitted along the axial direction on the outer peripheral surface of the camshaft 1, and is coaxially fitted on the outer peripheral portion of the bush 6a. And a dish-shaped flange 6b. A stopper ring 15 is provided at the right end in FIG. 1 of the outer peripheral surface of the camshaft 1 on which the governor slider 6 is fitted.
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 is directed toward the governor holder 5 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 in FIG.

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

Accordingly, since no centrifugal force is generated in the ball 8 before the engine is started, the ball 8 is positioned at the radially innermost end 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, when rotating, a centrifugal force is generated, so that the ball 8 moves radially outward of the guide slot 7a as shown by the imaginary line in FIG. The governor slider 6 is held at a position where the biasing force on the governor slider 6 from the 16 side is balanced. The engine is maintained at a constant speed in accordance with the displacement of the governor arm 16 in that state.

The governor mechanism using the ball weight is constructed as described above. The governor holder 5 for guiding the ball 8 is provided with the engaging projection 9 as described above.
a is prevented from slipping off in the axial direction by engagement of the circumferential groove 11 with the circumferential groove 11, and is prevented from rotating in the circumferential direction by engagement between the projection 13 and the engagement hole 14, and is assembled to the camshaft 1. I have. When assembling the governor holder 5, the cam gear 2 is fixed to the camshaft 1 in advance, the governor holder 5 is fitted into the camshaft 1 from the right end of the camshaft 1 in FIG. This is performed by pushing the governor holder 5 while aligning the protrusions 14 with the protrusions 13 so that the protrusions 13 are immersed in the recesses 14, and the engaging protrusions 9 a are elastically engaged with the circumferential grooves 11. Thus, the governor holder 5 can be easily assembled.

A pivot pin 17 extending in the axial direction is fixed to the left end face of the cam gear 2 in FIG. 1, as shown in FIG. The base end of a plate-shaped weight 18 formed in a C-shape is pivotally supported in a direction along the end face of the cam gear 2. The weight 18 is provided so as to substantially surround the camshaft 1 in the circumferential direction. An axial hole 1a is bored coaxially in the camshaft 1, and a part of the axial hole 1a is rotatably supported by a reduced diameter portion on the back side of the axial hole 1a. Decompression shaft 19
Are coaxially rotatably received. A circumferential groove 1 having a substantially semicircular cross-sectional shape is provided at an intermediate portion of the decompression shaft 19.
9a is formed over the entire circumference, and the decompression rod 2 is reciprocally received in the camshaft 1 so that the axes of the decompression rods are orthogonal to the decompression shaft 19.
1 is provided so that a part of the outer peripheral surface of the intermediate portion is received in the circumferential groove 19a. Thus, the decompression shaft 19 and the decompression rod 21 are provided so as to partially overlap each other and to be orthogonal to each other.

FIG. 5 and FIG. 1 showing enlarged main parts of FIG.
As shown in FIG. 6 showing an enlarged cross-sectional view of a main part corresponding to FIG. 6, a slit-shaped axis 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 the engagement pin 22 is received in the groove 19a. In a portion of the decompression rod 21 intersecting with the decompression shaft 19, a slit-shaped radial groove 21a cut in a direction orthogonal to the axis of the decompression rod 21 is formed, and an intermediate portion of the engagement pin 22 is formed. Both ends of the engaging pin 22 in the axial direction are received in the radial groove 21 a and the axial ends 19 b of the decompression shaft 19, respectively.
The two are engaged with each other via the engagement pin 22 such that the decompression rod 21 is displaced in the axial direction in accordance with 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 surfaces of the decompression rod 21, an intermediate engagement portion formed by cutting and raising at an intermediate portion of the weight 18, and the weight 18 so as to face the intermediate engagement portion with the decompression rod 21 interposed therebetween. The free end engaging portions formed by cutting and raising at the free end are in contact with each other. Accordingly, the decompression rod 21 reciprocates with the swinging 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, and the centrifugal force causes the weight 18 to swing such that the free end is displaced radially outward.
As shown in FIG. 3, a return spring 23, which is urged with a predetermined spring force, is connected to the weight 18 in a direction against the force in the swing direction due to the centrifugal force. The pin 20 for supporting the base end of the return spring 23 is fixed to the end face of the cam gear 2 opposite to the governor holder 5 in an upright state. It is formed coaxially so that it can be shared with the engaging hole 14.

The axial end of the shaft support of the decompression shaft 19 is extended to a position corresponding to the exhaust valve cam 3 and another exhaust valve cam (not shown). In addition, as shown in FIG. 7, a guide hole penetrating in a radial direction between the outer peripheral surface of the camshaft 1 and the axial hole 1a is formed in a portion of the camshaft 1 adjacent to the exhaust valve cam 3. 24 are drilled. A decompression pin 25 is supported in the guide hole 24 so as to be reciprocally movable.
The head of the camshaft 1 can protrude and retract from the outer peripheral surface of the camshaft 1.

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

Further, a portion of the decompression shaft 19 which contacts the decompression pin 25 is formed by a 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 is in contact with the arc surface of the decompression shaft 19, and the camshaft 1 resists the urging force of the C-shaped spring 26. The decomp pin 25 protrudes from the outer peripheral surface of. In this protruding state, the protruding end of the decomp pin 25 protrudes radially outward from the base circle of the exhaust valve cam 3, so that the exhaust valve is always opened. When the engine speed increases and the weight 18 swings in the direction of arrow A which is counterclockwise in FIG. 5 due to centrifugal force, the state shown by the imaginary line in FIG. 8 to the position shown in FIG. At this time, the flat surface 19 c of the D-shaped cross section of the decompression shaft 19 is
5b comes into contact, and the decomp pin 25 is pushed back by the urging force of the C-shaped spring 26. In this immersion state, the push rod 4 comes into sliding contact with the cam surface of the exhaust valve cam 3, and normal opening / closing valve control is performed.

An annular bottom plate 27 is provided between the cam gear 2 and the governor holder 5 so as to be movable in the circumferential direction in an annular recess provided on the end face of the cam gear 2 on the governor holder 5 side. Have been. As described above, the ball 8 is in contact with the bottom plate 27 through the opening of the guide slot 7a of the governor holder 5, and the ball 8 may directly contact the synthetic resin cam gear 2 in this embodiment. In addition, the cam gear 2 can be prevented from being worn by the movement of the ball 8.

[0025]

As described above, according to the present invention, the governor mechanism can be easily constructed using the ball and the governor holder, and the governor holder is moved in the axial direction while being fitted to 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 engagement of the elastic engaging piece and the engaging portion with the outer peripheral surface of the shaft. As a result, the governor holder can be easily assembled.

[Brief description of the 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 the line II-II in FIG.

FIG. 3 is a view taken along the line III-III in FIG. 1;

FIG. 4 is a view taken along line IV-IV in FIG. 3;

FIG. 5 is an enlarged view of a main part of FIG. 3;

FIG. 6 is an enlarged view corresponding to a main part of FIG. 1;

FIG. 7 is a view taken along line VII-VII of FIG. 1;

FIG. 8 is a view corresponding to FIG. 7 in an engine rotation state.

[Explanation of symbols]

 Reference Signs List 1 camshaft 1a axial hole 1b circumferential groove 2 cam gear 3 cam 4 push rod 5 governor holder 6 governor slider 6a bush 6b flange portion 7 arm portion 7a guide slot 8 ball 9 elastic engaging piece 9a engaging convex portion 11 circumferential groove Reference Signs List 12 concave portion 13 convex portion 14 engaging hole 15 retaining ring 16 governor arm 17 pivot pin 18 weight 19 decompression shaft 19a circumferential groove 19b axial direction groove 19c flat surface 21 decompression rod 22 engagement pin 22a groove 23 return spring 24 Guide hole 25 Decomp pin 25a Shoulder 25b Base end face 26 C-shaped spring 27 Bottom plate

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F02D 31/00 301 F02D 1/04

Claims (1)

(57) [Claims] 1. A governor holder fitted on a shaft that rotates with rotation of an engine and guiding a ball as a governor weight so as to be able to reciprocate in a radial direction of the shaft, and in accordance with the movement of the ball in the radial direction. A governor slider provided so as to engage with the ball so as to be displaceable in the axial direction, and the governor slider is resiliently pushed in a direction against the axial displacement force of the governor holder due to centrifugal force acting on the ball. A biasing means, an outward flange portion provided on a side of the shaft opposite to the ball guide side of the governor holder, and an axially protruding portion provided on one of the governor holder and the outward flange portion. An engagement convex portion, the governor holder and the outward flange portion engaging the engagement convex portion to prevent the governor holder from rotating. An engagement recess provided on one of the other, an elastic engagement piece provided on the inner peripheral surface of the governor holder so as to be elastically deformable in a radial direction, and engaging the elastic engagement piece with the governor holder. A governor mechanism provided with an engaging portion provided on an outer peripheral surface of the shaft to prevent the shaft from coming off.