JPS5913289Y2 - Pressure reducing lever device for multi-cylinder internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a pressure reducing device for a multi-cylinder internal combustion engine, and is particularly intended to perform a return action for returning from a reduced pressure state to a compressed state using an extremely simple structure.

Such a pressure reducing device for a multi-cylinder internal combustion engine uses a cam, a lever, a link mechanism, etc. to reduce the pressure of the intake valve against the valve plate and reduce the pressure in the cylinder. A pressure reducing device as shown is possible.

That is, in this device, the tip 2 of a valve pusher rod 1, which moves up and down by the action of a cam provided on a camshaft (not shown), is provided at one end of a drive-side lever 5 of a swinging arm 4 that swings around a swinging center 3. The receiver is engaged with a plate 6, and the other end of the swinging arm 4 constitutes a valve arm 7 for pressing downwardly the valve top 8 provided directly below the swinging arm 4, so that the valve push rod 1 rises. shaking arms 4
When the valve arm 7 swings clockwise around the center 3, the valve arm 7 presses the valve top 8 downward, and pushes down the valve stem 9 integrated with the valve top 8 and the intake valve (not shown) provided at its lower end. A horizontal insertion hole 12 into which a decompression shaft 11 is inserted is provided in the side wall of the bonnet 10.

Further, one end 13 of the decompression shaft 11 protrudes above the valve arm 7, and the end 13 has a notch 14 into which the valve arm 7 fits through a space 15. , and the other end 16 of the decompression shaft 11 is connected to the stepped portion 1
A torsion spring 18 is installed between the stepped portion 17 and the bonnet 1-10, a decompression prepper 19 is fixed to the stepped portion 17 with a bolt 2o, and a link 22 is attached to the tip 21 of the decompression prepper 19. It is engaged by a bolt 23.

Therefore, when the link 22 is moved in a direction perpendicular to the plane of the paper, the decompression lever 19 rotates around the decompression shaft 11, and the decompression shaft 11 integrated with the decompression prepper 19 rotates.
The outer surface 24 of the end 13 of is in contact with the upper surface 25 of the valve arm 7,
Since the upper surface 25 is pressed slightly downward, the valve top 8 and the intake valve (not shown) are always pressed downward by a certain amount or more, and the pressure in the cylinder is reduced.If the force for moving the link 22 is released, each Due to the restoring force of the torsion spring 18 provided for each cylinder, the retainer combination lever 19 returns to its original state, and the decompression shaft 11 simultaneously returns to the state in which it does not push the valve arm 7 (ie, the compressed state).

The conventional example described above has the advantage of being easy to operate, in that it is possible to reduce the pressure in each cylinder at the same time by simply moving the link 22, but on the other hand, it is necessary to provide a torsion spring 18 for each cylinder. In addition to having a large number of parts and making the device expensive, torsion springs have a short lifespan, and especially when installed directly on a high-temperature bonnet as mentioned above, they tend to wear out quickly and make it difficult to ensure accurate operation. be.

Furthermore, since the torsion spring is inserted into the decompression shaft, the combination shaft becomes long, and the torque generated by the force applied to the decompression lever causes premature wear between the insertion hole 12 and the decompression shaft 11. In addition, the decompression shaft has disadvantages in that it increases material costs and processing costs, and takes up a large amount of space because the amount of protrusion of the decompression shaft from the bonnet 10 is large.

The present invention has been devised to improve the drawbacks of the conventional device described above, and includes providing at least one return spring between any adjacent decompression levers, and adjusting the mounting position of the return spring on both decompression levers. An object of the present invention is to provide a decompression lever device for a multi-cylinder internal combustion engine in which the decompression lever automatically returns from a decompression position to a compression position by providing a difference between the distance between the decompression lever and the center of rotation. It is.

Hereinafter, embodiments of the pressure reducing lever device according to the present invention will be described in detail with further reference to the accompanying drawings starting from FIG.

FIG. 2 is a front view of the decompression lever device of the present invention including a part of the engine, and FIG. 3 is a sectional view taken along line A-A in FIG. The valve arm 37, which is one arm of the swinging arm 36, is inserted into the notch 35 at the tip that protrudes into the bonnet 32. It is inserted through a space 39 between the cutout 35 and the lower surface 38 of the cutout 35 .

The lower end 44 of the decompression prepper 43 is fixed to the other end 40 of the decompression shaft 31 that protrudes outside the bonnet 33 through a washer 42 with a bolt 41, and the decompression preper 43 swings to move the decompression shaft 31 into the insertion hole 34. An O-ring 45 is installed in a groove 44 provided in the insertion hole 34 on the decompression shaft 31.

On the other hand, a decompression prepper 43.43.
... has a port 48 attached to the link 47 at its upper end 46.
When one decompression prepper 43 is swung, all the decompression preppers 43, 43...
The decompression prepers 43a and 43b are constructed so that they can swing simultaneously at the same angle, and as is clear from FIG. 2, a return spring 49 is attached at spring attachment positions 50a and 50b between the pair of decompression prepers 43a and 43b.

In this embodiment, the return spring 49 is a tension spring, and the rotation center 52 b of the decompression lever 43 b is located on the side toward which the arrow 51 indicating the swinging of the decompression prepper 43 in the pressure reduction direction is directed.
to the mounting position 50b of the return spring 49 R'
is the center of rotation 52 of the other combination lever 43a.
The distance R is larger than the distance R from a to the mounting position 50a of the return spring 49.

Next, to explain the operation of this embodiment, when the decompression prepper 43 is in the position shown in FIG. 2, that is, in the compressed state, the decompression shaft 31 is in the state shown in FIG. and decompression shaft 4
A space 39 exists between the lower surface 38 of the notch 35 of No. 3, and the valve arm 37 and the decombination shaft 31 do not interfere in any way. Therefore, when the intake valve (not shown) is closed, the intake valve has a spring 52 on the valve seat. It is crimped by force and becomes in a so-called compressed state.

Next, when depressurizing, pull the link 47 in the direction of arrow 51 and rotate each of the combined levers 43 in the direction of arrow 51 at the same time, and the decompression shaft 31 will also rotate around its axis at the same time, closing the intake valve. When the valve arm 3
The upper plane 25 of the valve arm 37 when the valve arm 7 is lifted up.
comes into contact with the outer surface 24 of the decompression shaft 31 and prevents the intake valve from being safely closed. However, in order to return to the compressed state, if the pulling force on the link 47 is released, the decompression prepper 43 is released by the action of the return spring 49. As a result, the state shown in FIG. 2 is restored all at once.

That is, when comparing the tensile force of the return spring 49 in the compressed state shown in FIG. 2 and the reduced pressure state in which the link 47 is pulled in the direction of the arrow 51, it is clear from FIG. 4 that by making R' larger than R, Since the distance 1' between the mounting positions 50a' and 5Qb' of the return spring 49' in the reduced pressure state is larger than the distance 1 between the mounting positions 50a and 50b of the return spring 49 in the compressed state, the tensile force of the return spring 49 in the reduced pressure state is becomes larger than the compressed state, and if the force pulling the link 47 in the depressurizing direction is released, the entire combined lever 43, 43...
- returns to the compressed state all at once.

In the above embodiment, the return spring 49 is a tension spring, but if R is made larger than R', the same effect can be produced even if a compression spring is used.

In addition, the above function can be achieved by providing only one return spring 49 between a pair of adjacent decompression levers.
It is also possible to provide a plurality of return springs between the plurality of pairs of decompression levers if necessary.

As described above, the present invention provides a return spring between any adjacent decompression levers, and also provides a difference between the mounting position of the return spring on both decompression levers and the distance between the center of rotation of both decompression levers. This method eliminates the need to provide a torsion spring on each decompression shaft as in the conventional method, reducing the number of parts, prolonging the life of the return spring, and making the length of the decompression shaft extremely short, saving space and making it ideal for use with combination levers. Since the torque generated by this force is also small, there is little wear between the insertion hole and the decompression shaft, making it possible to provide a decompression lever device with reduced cost and high reliability.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional pressure reducing device, Fig. 2 is a front view of an embodiment of the present invention, Fig. 3 is a sectional view taken along line A-A in Fig. 2, and Fig. 4 is the operating principle of the present invention. FIG. 2 is a schematic explanatory diagram of a combination lever for explaining. 43, 43 a, 43 b...Decompression lever, 47...Link, 49...Return spring, 50.501.50 b...Mounting position, R
, R'...Rotation center 52 of the decompression prepper 43
Mounting position 50a, 50b of return spring 49 from a, 52b
Interval up to, 52.52 a, 52 b...
Rotation center.

Claims (1)

[Claims for Utility Model Registration] The decompression preppers 43 provided for each cylinder are connected by a link 47, and the decompression preppers 4 of the gold cylinder are connected by the link 47.
In the decompression device in which the decompression preppers 43a and 43b are operated at the same time, a return spring 49 is provided between any adjacent decompression preppers 43a and 43b, and the mounting position 50a of the return spring 49 is on both decompression preppers 43a and 43b.
50b and both decompression preppers 433, 43b rotation center 5
2a and 52b so that the decompressor preparer 43 automatically returns from the pressure reducing position to the compression position by providing a difference between the intervals R and R'. 2. The return spring 49 is composed of a tension spring,
In addition, the distance R' from the center of rotation 52b of the decompression preparer 43b provided on the decompression direction side of any adjacent decompression preparer 43a, 43b to the mounting position 50b of the return spring 49 is equal to the center of rotation 52 of the other decompression preparer 43a.
Distance R from a to the mounting position 50 a of the return spring 49
The first claim for utility model registration, which has a larger structure
A pressure reducing lever device for a multi-cylinder internal combustion engine as described in 2.