CN201155345Y - Decompression device for manual start gasoline engine - Google Patents

Abstract

The utility model discloses a decompression device for a manual starting gasoline engine. The decompression device is arranged between a timing driven wheel and an exhaust cam. The decompression device includes a weight block, a weight shaft, a top block, and a tension spring and the fixed plate; the counterweight shaft is bent at right angles, one side of which is perpendicular to the camshaft and connected to the counterweight, and the other side is parallel to the camshaft and connected to the top block after passing through the shaft hole on the fixed plate. One end of the tension spring used to control the rotation of the counterweight shaft is hung on the timing driven wheel, and the other end is hung on the counterweight shaft; the shape of the top block should ensure that when the counterweight shaft rotates around the shaft hole on the fixed plate, the top block can change The profile of the exhaust cam. The utility model has strong universality and compact structure, and can be applied to most hand-start gasoline engines through a simple design, so that the starting is easy and smooth.

Description

Decompression device for manual start gasoline engine

technical field

The utility model relates to a hand-start decompression device used in a hand-start gasoline engine.

Background technique

Hand-start gasoline engines are widely used in garden machinery. When starting the gasoline engine, the user pulls the pull rope with arm strength. The user's arm strength is high, and it is often necessary to repeatedly pull the pull rope to start. The existing decompression device of the manual starter has a complex structure or poor versatility.

Contents of the invention

Purpose of the invention: The purpose of this utility model is to provide a starting decompression device for a hand-start gasoline engine that is easy and smooth to start.

Technical solution: The decompression device of the hand-start gasoline engine described in the utility model is characterized in that the decompression device is arranged between the timing driven wheel and the exhaust cam, and the decompression device includes a counterweight, a counterweight shaft , top block, extension spring and fixed plate; the counterweight shaft is bent at right angles, one side is perpendicular to the camshaft and connected with the counterweight, and the other side is parallel to the camshaft and passes through the shaft hole on the fixed plate Connected with the top block, one end of the tension spring used to control the rotation of the counterweight shaft is hung on the timing driven wheel, and the other end is hung on the counterweight shaft; the shape of the top block should ensure that when the counterweight shaft rotates around the shaft hole on the fixed plate , the top block can change the profile of the exhaust cam. For this purpose, the top piece can be cam-shaped or round with cut edges. During manufacture, the counterweight, the counterweight shaft and the top block can be made into one.

The working principle of the utility model is: Figure 1 is the working state, when the rotating speed of the camshaft is lower than a certain value, the extension spring force is greater than the centrifugal force generated by the rotation of the counterweight and the top block, and the top block remains at the position shown in the figure, and the When the top block is higher than the base circle of the cam, the valve is pushed open, the pressure in the cylinder is reduced during the compression stroke, and the manual starting becomes easy and smooth.

Figure 4 is the non-working state. When the rotational speed of the camshaft is higher than a certain value, the tension spring force is smaller than the centrifugal force generated by the rotation of the counterweight and the top block. At this time, the top block rotates with the counterweight shaft. When the top block is lower than the cam At the base circle, the valve falls back to the fully closed state.

Beneficial effects: compared with the prior art, the utility model has the advantages of compact structure and high reliability, and is suitable for most hand-start gasoline engines.

Description of drawings

Fig. 1 is a schematic diagram of the working state structure of the utility model.

FIG. 2 is a schematic diagram of a cross-sectional structure in the right view direction of FIG. 1 .

FIG. 3 is a schematic top view of the structure of FIG. 1 .

Fig. 4 is a schematic cross-sectional view of the utility model in a non-working state.

Detailed ways

As shown in the figure, the symbols in the figure represent timing driven wheel 1, camshaft 2, intake cam 3, exhaust cam 4, counterweight 5, counterweight shaft 6, cam jack 7, extension spring 8, fixed plate 9. The timing driven wheel 1 is installed on one end of the camshaft 2, the exhaust cam 4 and the intake cam 3 are installed on the camshaft 2 in turn, and the counterweight shaft 6 is bent into a right angle, and one side is parallel to the center line of the camshaft 2. When the counterweight shaft 6 rotates around the shaft hole on the fixed plate 9, the cam top piece 7 changes the profile of the exhaust cam 4. One end of extension spring 8 is hung on the timing driven wheel 1, and the other end is hung on the counterweight shaft 6.

The utility model has a compact structure and takes up little space. The mechanism only needs to be installed with a tension spring and a fixed plate at a suitable position on the timing driven wheel. The critical speed at which the cam top block turns over can be determined by the tension of the extension spring, the quality of the cam top block and the counterweight, so as to adapt to different models, and the design is simple and versatile.

Claims (3)

1, a kind of decompressor that pulls starting up gasoline engine is characterized in that: decompressor is arranged between timing follower (1) and the exhaust cam (4), and this decompressor comprises balancing weight (5), balancer shaft (6), jacking block (7), extension spring (8) and fixed plate (9); Described balancer shaft (6) bending that meets at right angles, wherein vertical with camshaft (2) on one side, and be connected with balancing weight (5), another side is parallel with camshaft (2), and be connected with jacking block (7) after passing axis hole on the fixed plate (9), extension spring (8) one ends hang on the timing follower (1), and an end hangs on the balancer shaft (6); The axis hole rotation of balancer shaft (2) on fixed plate (9), jacking block (7) changes the molded lines of exhaust cam (4).

2, the decompressor that pulls starting up gasoline engine according to claim 1 is characterized in that: jacking block (7) is a cam face, or has the circle of side cut.

3, the decompressor that pulls starting up gasoline engine according to claim 1 and 2 is characterized in that: balancing weight (5), balancer shaft (6) and jacking block (7) are integral.

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