JPS611812A - Valve driving device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the durability of a light alloy rocker arm by fitting a casing made of a hard material to one end of the rocker arm, and also by accormodating a hydraulic lifter in the casing. CONSTITUTION:A rocker arm is made of a light alloy, and a cylindrical casing 20 with a bottom, made of a hard material is fitted to one end of the rocker arm 4. The plunger 7 of a hydraulic lifter 5 is inserted into the casing 20 so that it can slide freely in the casing 20. The plunger 7 is also placed against the upper end of a valve 6. Since the reaction force and load at lifting which are input to the hydraulic lifter 5 are received by casing 20 made of a hard material, the durability and reliability of the rocker arm is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a valve train for an internal combustion engine, and more particularly to a rocker arm with a built-in hydraulic lifter that automatically adjusts the valve clearance to zero based on hydraulic pressure. .

(Prior technology) Various valve train systems equipped with hydraulic valves or hydraulic tappets have been proposed to reduce the noise of internal combustion valve train systems and eliminate the need for adjusting valve gaps. One of them is a rocker arm with a built-in hydraulic lifter as shown in Figure 14. (See Utility Application No. 58-53738, etc.) To explain this, 1 is a rocker arm that is integrated with the -L section of the Isoseki cylinder head. 2 is a camshaft rotatably supported by the cam bracket 1; 3 is a hollow tubular rocker shaft supported at the side end of the cam bracket 1; 4 is a front ff, a; This is a rocker arm that is swingably supported by the lever shaft 3.The rocker arm 4 has its driven i4A in sliding contact with the cam 2A of the camshaft 2, while its swinging end 4B is connected to the stem end of the intake and exhaust valve via the hydraulic lifter 5. It is in contact with 6.

The hydraulic pressure lever 7 includes a tappet piston 7 that directly contacts the stem end 6, and a sleeve 9 that defines an oil reservoir chamber 8.
It is equipped with a check valve 11 interposed between the oil reservoir chamber 8 and the pressure chamber 10, and a coil spring j2 that always biases the tappet piston 7 in the protruding direction. 17 Ring-shaped holding hole 4 C1: is housed.

After passing through the f8 junction between the camshaft 2 and the cam bracket 1, the oil (TE) from the oil pump (not shown) passes through the passage 14 formed in the cam bracket 1 and the passage 15 in the rocker shaft 3. The oil is supplied to the oil hole 16 and the pongee receiving portion 4D of the rocker arm 4, and a part of the oil is introduced into the oil reservoir chamber 8 of the hydraulic lifter 5 as working oil pressure via the lubricating oil passage 13 of the rocker arm 4.

The working oil pressure introduced into the oil reservoir chamber 8 is checked based on the oil pressure drop in the pressure chamber 10 when the gap between the stem end 6 and the tappet piston 7 is about to expand while the intake/exhaust valve is closed. The valve 11 is opened to act on the pressure chamber 10 and push out the tappet piston 7. Therefore, the valve clearance is always adjusted to zero. On the other hand, when the reaction force from the stem end 6 acts on the tappet piston 7 when the intake/exhaust valve is opened, the pressure in the pressure chamber 10 increases and the check valve 11 closes, so the tappet piston 7 does not move back. ,
Therefore, the force of the cam 2A is effectively transmitted to the intake and exhaust valves.

(Problem to be solved by the invention, Hiroshi) By the way, in this device, the reaction force acting on the tappet piston 7 during cam rifting is input to the sleeve 9, and the bottom surface 4E of the holding hole 4C, which the distal end 9A of the sleeve 9 abuts. The reaction force is stopped at .

For this reason, when the rocker arm 4 is made of a lightweight material such as an aluminum alloy, the bottom surface 4E of the holding hole is likely to wear out due to repeated friction and impact force with the sleeve 9, and as this wear progresses, the hydraulic pressure will increase. Not only does it interfere with the operation of SrL, but it also has a negative effect on the operation of the valve train.
It's possible. On the other hand, if the rocker arm 4 is made of a relatively hard material such as iron or steel, the above-mentioned wear problem can be solved, but the inertial mass of the valve train increases, which lowers the rotational limit of the engine. Put it away.

(Means for Solving the Problems) According to the present invention, in the above-mentioned valve train in which a hydraulic lifter is disposed at the end of the rocker 7, the case portion housing the hydraulic lifter is made of a hard material. The bottom cylinder was formed into a cylindrical shape, and the bottom part was fitted into a holding hole formed at the end of the rocker arm.

(Function) According to the above configuration, the case part that the sleeve fJ of the hydraulic lever 7 comes into contact with is made of a hard material (therefore, wear is less likely to occur), and the case part 1 is not easily attached to the swinging end of the rocker arm. The rocker arm itself does not need to be very hard because the bottom surface 11 transmits the reaction force with a wide area such as the 7 run part provided as necessary. Embodiment) FIG. 1 shows an embodiment of the present invention. Substantially the same parts in FIG. 4 or between the embodiments below are designated by the same reference numerals.

In the figure, 20 is a steel material, vl is a bottomed cylindrical case portion made of a wear-resistant hard material such as ceramics, and 21 is a rocker arm swinging end 4Bj formed into which the case portion 20 is fitted. This is a holding hole for holding the joint.

The opening edge 4F of the holding hole 21 is located around the open end of the case portion 20 in which the hydraulic lifter 5 is housed.

(The bottom surface of the swinging end 4B) is formed with a 7-run no. 920A, while the holding hole 21 extends through the swinging end 4B. The bottom of the portion 20 is formed to protrude somewhat upward.

In this case, in order to supply the working oil pressure to the oil reservoir chamber 8, the outlet end of the lubricating oil passage 13 is formed in an annular shape along the inner peripheral surface of the holding hole 21, and an opening is opened at a position corresponding to this annular passage. This is done through the oil hole 22 provided on the bottom surface of the case portion 20 so as to do so.

As for the hydraulic lifter 5, the load input from the stem end 6 when the intake/exhaust valve lifts is stopped at the portion where the inner bottom surface 20B of the case s20 formed of a hard material contacts the sleeve end portion 9A.

Regarding rocker arm 4, case 7 run section 2OA
The receiver is stopped by the abutment surface between the and the swinging member 114B.

The contact surface is wider than the contact surface of the sleeve 9, and therefore the surface pressure acting on the bottom surface of the swinging end 4B is small.

In the figure, reference numeral 23 denotes a drawer 11-. A snap ring is used to prevent the case part 20 and the hydraulic valve 7 from falling off from the rocker arm 4 when the rocker arm 4 is assembled to the rocker shaft 3 or when the rocker shaft 3 is assembled to the sill head. The aim is to improve assembly workability. As such a retaining means, for example, a second
As shown in the figure, the cap 24 may be press-fitted into the bottom of the case portion 20.

! ¥S3 Figure shows another embodiment of this invention.

In the figure, 20 is a cylindrical case part, which has a bottomed holding hole 21 formed to have the same diameter as the case part 20, so that the outer bottom surface 20C is brought into contact with the bottom surface 21A of this holding hole 21. The hydraulic pressure is supplied to the six oil reservoir chambers 8 which are fitted and held in the same manner as in the embodiment shown in FIG.

When the intake/exhaust valve lifts, the load input from the stem end 61r is applied to the hydraulic slide 5, and the inner bottom surface 20B of the entrance part 20 formed of a hard material is applied to the sleeve end 9.
The receiver stops at the point of contact with A.

Also, if the rocker arm 41 is stuck,
The receiver is stopped by the contact surface between the Il bottom surface 20C and the bottom surface 21A of the holding hole 21. The contact surface is wider than the contact surface of the sleeve 9, and therefore the surface pressure acting on the bottom portion 21A is small.

(Effects of the Invention) According to the present invention, since the reaction force and load input to the hydraulic pressure lever during lift are stopped by the case portion made of a hard material, the rocker arm is secured while ensuring its durability and reliability. The internal combustion engine itself can be made of lightweight materials such as light metals and reinforced resins, and therefore has the effect of increasing the speed and output of the internal combustion engine.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sectional view of an embodiment of the present invention, pIS
FIG. 2 is a sectional view of another example of retaining the case portion. FIG. 3 is a partially cutaway sectional view of another embodiment of the invention. Fig. 4 is a partially cutaway sectional view of a conventional example.
...Rocker arm, 4B... Rocker arm swing! Mr.
a, 5...Hydraulic pressure slide, 7...Tappet piston,
8... Oil reservoir chamber, 9... Sleeve, 10... Pressure chamber, 11... Check valve, 12... Coil spring, 1
3... Lubricating oil passage, 20... Case g, 2OA...
・7 run part, 21...retention hole, 21A...bottom surface,
22...Oil hole, 23...Snap ring, 24
···cap.

Claims (1)

[Claims] In a valve train in which a hydraulic lifter is disposed at the end of a rocker arm of an internal combustion engine, a case portion for accommodating the hydraulic lifter is formed in a bottomed cylindrical shape from a hard material, and this case portion is formed in a holding hole at the end of the rocker arm. A valve train for an internal combustion engine, characterized in that it is fitted with a valve train.