JPH0640916Y2 - Governor device for general-purpose engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a governor device for a general-purpose engine that controls rotation at a constant speed.

(Prior Art) A general-purpose engine is provided with a governor device that keeps the rotation speed constant in response to demands for power generation and other uses.

An example of the governor device is shown in FIG.
The governor housing a is rotatably mounted by a support shaft b, and is rotated by a driven gear c provided on the outer periphery in conjunction with the crankshaft. A centrifugal weight d is axially supported in the governor housing a, and an engagement piece e at its inner end contacts the tail end of the governor slider f. A slot control lever g is elastically contacted with the tip of the governor slider f.
When a centrifugal force acts on the centrifugal weight d, the governor slider f is pushed out and the slot control lever g is pushed. The slot control lever g is set so as to lower the throttle opening when it moves in this direction and increase the throttle opening when it moves in the opposite direction. When the rotation speed decreases, the centrifugal force decreases, the throttle opening degree increases and the rotation speed increases, and conversely, when the rotation speed increases, the throttle opening degree decreases.

In this way, the centrifugal force of the centrifugal weight d and the urging force of the throttle control lever g at the set rotational speed are balanced, and the set constant rotational speed is maintained by the above-described action centering on that.

On the other hand, in a large-sized general-purpose engine, the decompression device is used because the operation force of the recoil starter or the like becomes excessive at the time of starting. In the decompression device, for example, as shown in FIG. 6, a decompression cam i that is projected and retracted by rocking is placed in a portion formed on the profile of the exhaust cam h so as to close the exhaust valve. The decompression cam i is provided with an engaging pin j so as to be engaged with a tip end of a centrifugal weight 1 axially mounted on a cam driven gear k or the like.

Thus, at the time of start-up, the decompression cam i projects above the exhaust cam h and the exhaust valve in the compression stroke is slightly opened, so the compression pressure is weakened and the operating force of the recoil starter and the like is saved. When the rotation is increased, the decompression cam i is retracted by the action of the centrifugal weight l, and normal valve control is performed.

The above-mentioned governor device and decompression device are used in a general-purpose engine, which complicates the structure of the engine part.

(Problems to be solved by the invention) This invention focuses on the fact that both the conventional governor device and the decompression device used for general-purpose engines use centrifugal weights, which are individually equipped to complicate the structure. Then
It is an object of the present invention to provide a general-purpose engine governor device having a simplified structure in which one centrifugal weight device has two control functions.

[Constitution of device]

(Means for Solving the Problem) With the above-mentioned object, the governor device for a general-purpose engine of the present invention has a centrifugal weight support plate for supporting the centrifugal weight fixed to the valve operating camshaft and a slider rotating. The slider is integrally and slidably mounted, and this slider is integrally provided with a decompression cam extending in the exhaust cam direction, and is pressed in the exhaust cam direction by a spring.
The decompression cam tip is made to overlap the valve closing portion of the exhaust cam, and the tip of the throttle control lever is elastically contacted.The centrifugal weight is slidable in a centrifugal direction to attach a slider. The engaging piece that pushes in the axial direction against the biasing force of the spring is integrally formed.

(Operation) With this configuration, the slider is axially controlled by the centrifugal weight, and at the time of starting, the decompression cam integrally installed is on the profile of the exhaust cam and the exhaust valve is slightly opened. While reducing the starting operation force, after starting, the decompression cam retracts due to axial movement and shifts to normal valve control, and further axial movement advances due to the increase in rotation, and the spring with the biasing force of the throttle control lever is applied. A constant number of rotations is maintained by the balance with the force.

(Embodiment) FIGS. 1 to 4 show an embodiment of the present invention.

Reference numeral 1 denotes a valve actuating cam shaft, which is driven by a driven gear 2 in conjunction with a crankshaft, and an intake cam 3 and an exhaust cam 4 open and close the intake valve and the exhaust valve, respectively.

On the camshaft 1, a centrifugal weight support plate 5 that supports a centrifugal weight 6 is fixed adjacent to the exhaust cam 4, and a slider 7 is interposed by a guide pin 8 interposed between the camshaft 1 and the camshaft 1. The shaft is mounted so that it can rotate and slide in the axial direction.

The slider 7 has a decompression cam extending in the direction of the exhaust cam 4.
10 is projected and is urged toward the exhaust cam 4 by the spring 9, and the tip 10a of the decompression cam 10 is placed on the profile of the exhaust cam 4 so as to overlap with the portion formed to close the exhaust valve.

A throttle control lever 11 is elastically contacted with the slider 7 on the side opposite to the exhaust cam. The throttle control lever 11 is set so that when it moves in the direction of the exhaust cam 4, the throttle opening degree decreases, and when it moves in the opposite direction, the throttle opening degree increases.

An engaging piece 6a extending in the centripetal direction is provided on the centrifugal weight 6 and is in contact with the exhaust cam 4 side of the slider 7. When a centrifugal force acts on the centrifugal weight 6, the engaging piece
6a pushes the slider 7 against the force of the spring 9.

It is configured as described above and operates as follows.

First, at the time of start-up, the tip end 10a of the decompression cam projects above the exhaust cam 4 to slightly open the exhaust valve in the compression stroke, so that the compression pressure is weakened and the operation force of the recoil starter or the like is saved. That is, it becomes easier to start.

When the rotation is increased, the slider 7 is moved by the action of the centrifugal weight 6.
Moves and the tip 10a of the decompression cam retracts from the exhaust cam, and the exhaust valve is controlled to open and close normally to operate the engine.

At this time, the throttle opening by the slot control lever 11 is large and the engine is rapidly accelerated. As the rotation speed increases, the centrifugal force increases and the slider 7 and the slot control lever 11 are greatly moved, and the throttle opening degree decreases. When the centrifugal force and the urging force of the spring 9 and the slot control lever 11 are balanced at a certain rotation speed, the constant speed operation is started. This constant speed rotation speed is set by selecting the biasing force of the slot control lever 11 and the like.

If the rotation decreases from this state, the centrifugal force decreases, the throttle opening increases, the rotation increases and returns to a certain number of rotations, and conversely when the rotation increases, the centrifugal force increases and the throttle opening decreases. However, the rotation is reduced and the action of returning to the original speed is always performed. In this way, the above operation is repeated around the set rotation speed, and the constant rotation speed is maintained.

[Advantages of the Invention] As described above, in the governor device for a general-purpose engine according to the present invention, the camshaft for valve operation is provided with the centrifugal weight device and the rotation integral and slidable sliders that engage with the centrifugal weight device. In this slider, the decompression cam is integrally projected, and the spring is pressed against the centrifugal force acting direction of the centrifugal weight device by a spring, and the tip of the throttle control lever is elastically contacted.
With one centrifugal weight device, the two functions of the decompression device and the governor device are made to function, and there is an effect that the structure of the general-purpose engine is simplified and the cost is reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a governor device according to an embodiment of the present invention, FIG. 2 is a vertical sectional side view taken along the arrow AA in FIG. 1, and FIG. 3 is a vertical sectional side view taken along the arrow BB in FIG. 4 is a perspective view of the slider of FIG. 1, FIG. 5 is a vertical sectional front view of a conventional governor device, and FIG. 6 is a vertical sectional front view of a conventional decompression device. 1 ... Cam shaft, 4 ... Exhaust cam, 5 ... Centrifugal weight support plate, 6 ... Centrifugal weight, 7 ... Slider, 9 ... Spring, 10 ... Decompression cam, 10a ...
Decompression cam tip, 11 …… Throttle control lever.

Claims (1)

[Scope of utility model registration request] 1. A centrifugal weight support plate for supporting a centrifugal weight is fixed to a valve operating camshaft, and
A slider is integrally mounted so as to be rotatable and slidably mounted. This slider is integrally provided with a decompression cam extending in the exhaust cam direction, and is pressed in the exhaust cam direction by a spring, so that the tip of the decompression cam closes the valve of the exhaust cam. The throttle control lever is elastically contacted with the tip of the throttle control lever, and the centrifugal weight is swung in the centrifugal direction so that the slider resists the urging force of the spring. A governor device for a general-purpose engine, characterized in that an engaging piece that pushes in the axial direction is formed integrally.