JPS6258005A - Starting decompressor for engine - Google Patents

Abstract

PURPOSE:To simplify operation with obtaining the decompression action for a necessary time at the one time lever operation of a decompressor, by pivotably supporting a rocker arm with a hydraulic rush adjustor adjusting automatically the clearance of a tappet mechanism. CONSTITUTION:When the wire of a decompressor is stretched on starting of an engine, the lever 19 of the decompressor is pivotally moved to the position of a full line, so that a decompressor cam 20 presses down a rocker arm 9. Thereby, an exhaust valve 4 is lowered to the position of a full line so as to open against a valve spring 5. At the same time, a hydraulic rush adjustor body 12 also descends to the position of a full line. Then, after oil flows into a high pressure chamber 16 from a reservoir chamber 13 by the action of a check valve 15, this oil leaks through the gap between the adjustor body 12 and a plunger 14, so that the adjustor body 12 is raised gradually. Therefore, the decompressor action of a necessary time can be obtained at a one time operation.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention allows compressed gas in the cylinder to escape to the exhaust hole when starting the engine of a car, motorcycle, etc.
This invention relates to a decompressor (reducing pressure) device that facilitates startup.

(Prior art) Conventionally, when starting an engine in a motorcycle or the like, the compression pressure in the cylinder is released and the piston is allowed to reciprocate up and down with a light load before the engine starts without any inconvenience. An easy-to-start decompressor device is used.

By the way, in a motorcycle that starts the engine using the kick method, in order to activate the decompressor device, pull the decompressor lever, perform a kick operation, and then return the decompressor lever to simulate starting the engine. It was difficult to operate. -Furthermore, in the case where the engine is started by driving the starter motor, the torque is relatively small immediately after starting the starter motor, so the starter motor must be continuously driven for a sufficient amount of time until the engine starts. Therefore, the operating time of the decompressor device, which lightens the load on the starter motor and facilitates starting, becomes longer.

However, with conventional decompressor equipment, during that period,
The decompressor lever must be continuously pulled, which is not easy to operate. Moreover, in general, the decompressor device forcibly opens the exhaust valve against the locking force of the exhaust valve spring.
The compressed gas in the cylinder is released to the exhaust hole, and it is tiring to continuously pull the decompressor lever against the biasing force of the exhaust valve spring. In addition, in the starter motor drive system, unless a decompressor device such as the one mentioned above is provided, the starting load is large, especially for engines with a large displacement per single cylinder, so a large-capacity battery and a large starter motor are required. It also has problems.

(Objective of the Invention) The present invention solves the above-mentioned problems. By simply pulling the decompressor lever once when starting the engine, the decompressor can operate continuously for a reasonable period of time, which is different from the conventional method. To provide an engine starting decompressor device which is easy to operate without the need to continuously pull a decompressor lever.

(Structure of the Invention) The present invention is an engine starting decompressor device that releases compressed gas in a cylinder to an exhaust hole when the engine is started. In addition to being pivotally supported, a suppression mechanism is provided that pushes down the rocker arm and opens the exhaust valve when the decompressor lever is operated when the engine is started.

With this configuration, when the rocker arm is pushed down by operating the decompressor lever, the hydraulic lash adjuster extends and oil is supplied to it, causing the exhaust valve to open until oil leaks from the hydraulic lash adjuster. It is something that continues to be said.

(Example) In FIGS. 1 to 3, 1 is a cylinder head of an engine, and an exhaust valve 4 for opening and closing an exhaust hole 3 opening into a combustion chamber 2 in the cylinder is supported so as to be able to reciprocate up and down. 5 is a valve spring fitted onto the valve stem 6 of the exhaust valve 4 and biases the exhaust valve 4 in the closing direction; 7 is a camshaft having a cam 8 driven by the rotation of the engine crankshaft; 9 is a movable spring; A rocker arm that constitutes a valve mechanism. One end of this rocker arm 9 is in sliding contact with the cam 8, and the other end is in contact with the upper end of the valve stem 6.
The intermediate portion is pivotally supported by a hydraulic lash adjuster 10, which will be described later. The hydraulic lash adjuster 10 automatically adjusts the clearance of the valve mechanism, and may be of a well-known structure provided on the cylinder head cover 11.
A spherical hollow adjuster body 12 whose lower end pivots around the rocker arm 9 and which moves up and down; a plunger t714 that is fitted into the hollow part of the adjuster body 12 and has a reservoir chamber 13 in the center; and a lower end of the plunger 14. A check valve 15 is formed in a check valve case provided corresponding to the oil passage hole in the section, and is biased in a direction to close the oil passage hole by a check valve spring, and is formed between the adjuster body 12 and the plunger 14. The plunger ring 17 is provided in the high pressure chamber 16 and biases the adjuster body 12 in a downward direction.

An oil supply path 18 and an adjuster body 1 are connected to the reservoir chamber 13 by an oil pump (not shown).
2. Oil is supplied through the oil passage of the plunger 14.

Also, when the adjuster body 12 descends, the check valve 1
5, oil flows from the reservoir chamber 13 into the high pressure chamber 16, and from that state, the oil in the high pressure chamber 16 leaks through the gap between the 1F stabilizer body 12 and the plunger 14, causing the adjuster to leak. body 1
2 rises slowly. Note that the downward movement of the adjuster body 12 is performed by the plunger spring 17 and the check valve 15.
It is done instantly by the action of

Reference numeral 19 denotes a decompressor lever as a pressing mechanism that pushes down the side of the rocker arm 9 that comes into contact with the valve stem 6. This decompressor lever 19 is provided with a decompressor cam 20 that comes into contact with the rocker arm 9 at one end, and a decompressor cam 20 that comes into contact with the rocker arm 9 at the other end. Decompressor wire 21 (Fig. 2, 3)
Figure) is connected.

Next, the operation of the above configuration will be explained.

By pulling the decompressor wire 21 when starting the engine, the decompressor lever 19 rotates from the state shown by the dashed-dotted line to the state shown by the solid line, and the decompressor cam 20 pushes down the rocker arm 9 to the state shown by the dashed-dotted line. Therefore, the exhaust valve 4 changes from the one-dot chain line state to the solid line state,
The exhaust valve 4 is forcibly opened against the valve spring 5. At the same time, the adjuster body 12 of the hydraulic lash adjuster 10 also descends from the state shown by the dashed line to the state shown by the solid line. In this way, Ajisesta body 12
Once it falls, it does not return to its original state instantly as described above, but gradually rises depending on the rate at which oil leaks through the gap between the adjuster body 12 and the plunger 14. Therefore, during that time, even if the pulling operation of the decompressor wire 21 is released and the decompressor lever 19 returns to the state shown by the dashed-dotted line, and the decompressor cam 20 is released from pushing down the rocker arm 9, the rocker arm 9 and The exhaust valve 4 gradually transitions from the state shown by the solid line to the state shown by the dashed-dotted line.

Through this operation, the exhaust valve 4 is forcibly opened for a predetermined period of time by only one operation of the decompressor wire 21, even if the tension operation is not continued, and the compressed gas in the combustion chamber 2 of the cylinder is It is released into the exhaust hole 3.

Then, this predetermined time may be set to a time necessary for the decompressor to operate when starting the engine.

In this way, a single operation of the decompressor lever 19 provides decompressor action for the required time, which not only simplifies the operation, but also allows continuous operation of the exhaust valve 4.
In order to open the valve, there is no need to apply force against the biasing force of the valve spring 5, so there is no fatigue due to the operation, and it is easy to use. Furthermore, it goes without saying that by providing the decombrestor device, it is possible to reduce the capacity of the battery and the size of the starter motor.

In addition, to start the engine, it generally takes one hour longer to use the decompressor when the engine is cold than when it is warm, but as in the present invention, the required time is secured by using the oil leak from the hydraulic lash adjuster 10. This is advantageous because the viscosity of the oil increases when it is cold, and it takes a long time for leakage to occur.

In addition, in order to secure the predetermined time required for the de-embresser, the adjuster body 12 and the plunger t? The amount of oil leak through the gap 14 may be set appropriately, and it is also conceivable to separately provide an orifice for adjusting the leak m in the oil passage.

(Effects of the Invention) As described above, according to the present invention, the rocker arm is pivotally supported by the hydraulic lash adjuster, and the rocker arm is pushed down by operating the decompressor lever when starting the engine. Since the decompressor starts for one hour by utilizing the slow recovery action caused by the oil leak of the type lash adjuster 1/star, the decompressor action for the required time can be obtained with one operation of the decompressor lever. Since there is no need to continuously pull the decompressor lever, the operation becomes easier and user-friendliness improves.

In addition, the decompressor takes one hour longer to start the engine when it is cold than when it is warm, but due to changes in oil viscosity, the oil leak time meets the above requirements, allowing for accurate startup decompressor action. is obtained.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of the engine starting decompressor device of the present invention, FIG. 2 is a schematic top view of the same device, and FIG. 3 is a side sectional view of a portion of the decompressor lever of the same device. It is. 3...Exhaust hole, 4...Exhaust valve, 9...Rocker arm, 10...Hydraulic lash adjuster, 19
...Decompressor lever (pressing mechanism). Patent applicant: Yamaha Motor Co., Ltd. Agent
Patent Attorney Etsushi Kotani Patent Attorney
1) Masamukai Patent Attorney Yasuo Itaya Figure 1

Claims (1)

[Claims] 1. In the engine starting decompressor device, which releases compressed gas in the cylinder to the exhaust hole when the engine is started, the rocker arm is pivoted by a hydraulic lash adjuster that automatically adjusts the clearance of the valve mechanism, and the engine starts. An engine starting decompressor device comprising a pressing mechanism that pushes down the rocker arm and opens the exhaust valve when the decompressor lever is operated.