JPH0455205Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an oil tappet. More specifically, the present invention relates to improvements in oil tappets that control the operation of intake and exhaust valve systems, etc. of internal combustion engines.

[Conventional technology]

At high speeds, the intake and exhaust valve systems of internal combustion engines may not be able to perform normal opening and closing operations due to intake and exhaust inertia, which tends to cause pumping losses and increase fuel consumption. For this reason, the tappet, which is a part of the operation control system of the intake and exhaust valve system, is equipped with a mechanism that adjusts the operation timing and stroke of the intake and exhaust valve system. Eligibility for adjustment and simplicity of structure are required.

[The problem that the idea aims to solve]

Conventionally, an oil tappet using oil pressure has been known as the adjustment mechanism, and has a general structure as shown in FIG. 4.

This conventional oil tappet T is slidably mounted in a mounting hole 2 formed in a cylinder block 1, etc., and is driven by a cam 3. The effective stroke of the oil tappet T is varied by controlling the oil pressure supplied from the oil supply path 4 and sliding a plunger (not shown) built in the oil tappet T. A push rod 5 is connected to the plunger, and by varying the effective stroke of the oil tappet T, the timing and stroke of opening and closing the valve 7 can be varied via the rocker arm 6.

Specific examples of such conventional oil tappets are known as Japanese Patent Publication No. 55-8647 and Japanese Patent Publication No. 55-14894, but as a result of pursuing suitability in adjusting the adjustment mechanism, the structure became complicated and manufacturing was difficult. The process becomes troublesome, increasing manufacturing costs, and there is a risk of wear and tear caused by complicated operations.

The present invention has been developed in view of the prior art described above, and its purpose is to simplify the structure without impairing the adjustability of the tappet.

[Means to solve the problem]

To achieve the above object, the oil tappet according to the present invention includes a tappet body that is slidably installed in a mounting hole formed in a cylinder block or the like and is driven by a cam, and a plunger that is slidably fitted into the tappet body. and an oil chamber that is formed inside the tapepet body and supplies hydraulic pressure to the plunger via a check valve, and the effective stroke of the tapepet body and the plunger can be made variable by controlling the hydraulic pressure supplied to the plunger. , both cylindrical ends are slidably fitted around the outer periphery of the tapepet body, and one end is applied with hydraulic pressure proportional to the engine speed, and the other end is pressed by a spring that acts in a direction opposite to the force caused by the hydraulic pressure. In between,
A sleeve is provided with a leak hole in the tapepet body communicating with the oil chamber formed by the tapepet body and the plunger, and a leak hole communicating with the leak chamber that overlaps and communicates with each other and is shut off and closed by vertical movement of the tapepet body. A leak chamber is formed between the oil chamber and the leak chamber, and the timing when the leak holes, which are formed in the tapepet body and the sleeve to communicate with each other, overlap each other, communicate with each other, or shut off and close is controlled by hydraulic pressure proportional to the engine speed. It is characterized by being controlled.

[Effect]

The oil tappet according to the present invention changes the effective stroke by leaking oil from the oil chamber to the leak chamber through the leak hole using hydraulic pressure proportional to the engine speed, and when the hydraulic pressure is high, the oil tappet slides with the hydraulic pressure. The effective stroke is shortened by delaying the timing at which the leak hole in the sleeve and the leak hole in the tappet body driven by the cam are connected or shut off, and when the oil pressure is low, the timing at which the leak hole in the sleeve and the leak hole in the tappet body that is driven by the cam are connected or shut off is delayed, and when the oil pressure is low, the leak hole is connected or shut off when the oil pressure is low. The effective stroke is lengthened by accelerating the timing of the stroke.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the oil tappet according to the present invention will be described below with reference to FIGS. 1 to 3.

The oil tappet according to the present invention has the main components of a tappet body 8, a plunger 9, an oil chamber 10, a sleeve 11, and a leak chamber 12, as shown in FIG.

The tapepet body 8 is slidably mounted in a mounting hole 2 formed in the cylinder block 1 and is driven by the cam 3. An oil passage 8a is provided at one end of the tapepet body 8, and an oil passage 8a is provided in the mounting hole 2 to supply oil.
An oil inlet 8b communicates with the oil supply passage 4 provided in the cylinder block 1, and an insertion part 8c into which the plunger 9 is inserted is formed at the other end.

The plunger 9 is slidably inserted into the charging portion 8c, and a push rod 5 is attached to one end of the plunger 9.
are connected.

The oil chamber 10 is formed between the plunger 9 and an oil passage 8a of the tapepet body 8, and a check valve 13 consisting of a ball 13b pressed by a spring 13a is built into the end of the oil passage 8a.

The sleeve 11 is cylindrical and is fitted around the outer periphery of the tapepet body 8 in the vicinity of the oil chamber 10. One end of the sleeve 11 has a flange 11a facing the oil supply path 4, and a hydraulic pressure proportional to the engine speed acts thereon. . A spring 11b is provided between the other end of the sleeve 11 and a retainer 14 fixed to the cylinder block 1, and is pressed in a direction opposite to the force of the hydraulic pressure, that is, in the direction of one end.

The leak chamber 12 is formed between the sleeve 11 and the cylinder block 1, and the leak chamber 12 is formed between the sleeve 11 and the cylinder block 1.
The diameter of the sleeve 11 is larger than that of the sleeve 11.

In such main components, a retainer 15 is fixed to the end of the insertion part 8c of the tapepet body 8 to prevent the plunger 9 from coming off, and an oil chamber 10 and a leak chamber 12 are attached to the tapepet body 8 and sleeve 11. leak holes 8d for polymerizing communication and blocking/closing between the
11c is bored to communicate with the oil chamber 10 and the leak chamber 12.

When oil proportional to the engine speed is supplied to such an oil tappet from the oil supply passage 4 of the cylinder block 1, the oil that has entered the oil passage 8a from the oil inlet 8b of the tappet body 8 will flow into the ball of the check valve 13. 13b and enter the oil chamber 10. and,
When the tappet body 8 is driven by the cam 3, the oil in the oil chamber 10 flows through the check valve 1.
3 prevents backflow and compresses the plunger 9.
is slid integrally with the tappet body 8, and the valve 7 is operated via the push rod 5 and the rocker arm 6 shown in FIG.

Figures 2 and 3 show oil leakage from the oil chamber 10 to the leak chamber 12. Figure 2 shows the case when the supplied oil is at low pressure, and Figure 3 shows the case when the supplied oil is at high pressure. .

The oil that has entered the oil chamber 10 through the above-described route leaks to the leak chamber 12 when both the leak holes 8d and 11c are at least partially overlapped, and the flange 11a of the sleeve 11 faces the oil supply path 4. This means that the entire sleeve 11 is moving (moving upward in the drawing). This amount of movement varies depending on the oil pressure depending on the rotation speed, so
Leak hole 8 of tapepet body 8 driven by cam 3
The timing at which d completely blocks and closes the leak hole 11c of the sleeve 11 to prevent oil leakage is different. In other words, the higher the oil pressure, the more the timing will deviate. 2 and 3, the lengths H and H' of the end of the leak hole 8d of the tappet body 8 and the oil supply passage 4 are compared. In other words, this difference in the timing of leak prevention is due to the difference in the effective stroke of the tappet made up of the tappet body 8 and the plunger 9 (the higher the oil pressure, the shorter the effective stroke, and the lower the oil pressure, the longer the effective stroke). Therefore, the operating timing and operating stroke of the valve 7 will be different. That is,
When the rotational speed of the internal combustion engine increases and the oil pressure becomes high, the operating timing of the valve 7 is delayed and the operating stroke is shortened, so that the adverse effects of intake and exhaust inertia can be eliminated.

On the other hand, when the rotation speed becomes low and the oil pressure becomes low,
Since the operating timing of the valve 7 is accelerated and the operating stroke is lengthened, proper opening and closing operations can be achieved.

In this way, the oil tappet according to the present invention can eliminate the adverse effects of intake and exhaust inertia at high speed rotation by controlling the supplied oil pressure, but this oil pressure control is based on the oil pressure of the lubricating circuit of a normal internal combustion engine. This lubrication circuit can be used because the rotation speed increases in proportion to the rotation speed, but it is also possible to attach a separate supply device and control it with a rotation sensor, controller, etc.

[Effect of idea]

As mentioned above, the oil tappet according to the present invention is
Compared to conventional oil tappets, the number of parts is small and the structure is simple, so it has the advantage of being easy to manufacture and having low manufacturing costs. Furthermore, the simple structure has the effect of reducing wear and damage, improving durability, and maintaining suitability for adjustment of the opening/closing operation timing of the intake and exhaust valve system.

Furthermore, although the oil tappet according to the present invention has a simple structure, it utilizes oil leakage, so the adjustment is smooth and accurate, and the increase in fuel consumption due to pumping loss at high speed rotation can be effectively reduced. It has the effect of preventing

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the oil tappet according to the present invention, FIGS. 2 and 3 are enlarged views of the essential parts of FIG. 1 in an operating state, and FIG. 4 is a sectional view showing a conventional example. 1...Cylinder block, 2...Mounting hole, 3...
...Cam, 4...Oil supply path, 8...Tappet body, 8d...Leak hole, 9...Plunger, 1
0...Oil chamber, 11...Sleeve, 11
c...Leak hole, 12...Leak chamber, 13
...Check valve.

Claims (1)

[Scope of utility model registration request] A tapepet body is slidably mounted in a mounting hole formed in a cylinder block or the like and driven by a cam, a plunger is slidably inserted into the tapepet body, and a check valve formed inside the tapepet body is inserted into the tapepet body. The oil tappet is provided with an oil chamber for supplying hydraulic pressure to the plunger, and the effective stroke of the tapepet body and the plunger is made variable by controlling the hydraulic pressure supplied to the plunger. A tapepet body and a plunger are formed between the two ends of a cylindrical body, one end of which is pressed by a spring acting in a direction opposite to the force of the oil pressure, and the other end being pressed by a spring acting in a direction opposite to the force of the oil pressure. A sleeve is provided in which a leak hole in a tapepet body communicating with an oil chamber is formed and a leak hole is formed in communication with a leak chamber that overlaps and communicates with each other or is blocked and closed by vertical movement of the tapepet body, and a leak chamber is formed between the sleeve and the cylinder block,
A feature is that the timing at which the leak holes, which are formed in the tapepet body and the sleeve to communicate the oil chamber and the leak chamber, are mutually overlapped and communicated with each other, and when they are shut off and closed is controlled by hydraulic pressure proportional to the engine rotation speed. Oil tappet.