JPS5987208A - Tappet valve mechanism - Google Patents

Abstract

PURPOSE:To facilitate the fitting of an oil hydraulic lifter itself into a limited space such as an engine room by assembling it in a rocker arm. CONSTITUTION:An oil hydraulic lifter 15 is directly arranged on the main body 19 of a rocker arm 11 and has a plunger 21 forming a pressure chamber 20. The pressure chamber 20 can be communicated to a reservoir chamber 24 through passages 22, 23, and this communication is controlled by a ball-type check valve 26. This check valve 26 is energized in the direction to cut off the communication by a relatively weak spring 28 with one end locked to a retainer 27, therefore the reservoir chamber 24 allows the working oil to flow only to the pressure chamber 20. When the plunger is moved upward to compress the pressure chamber 20, the working oil in the pressure chamber 20 flows out to the reservoir chamber 24 through a leak clearance 32 formed between the plunger 21 and the main body 19. The plunger 21 is extended or shrinked against the main body 19 of the rocker arm 11, thereby the valve clearance is kept zero.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve train, and more particularly to a valve train for use between internal combustion legs of a city shaft.

In the overhead cam type internal valve mechanism, a cam held on the camshaft is brought into contact with a rocker arm that rotates around the rocker arm axis, and the cam moves the [F] of the rocker arm.
]7 controls the opening and closing of the engine valves for intake and exhaust. In this type of valve train, a one-pressure lifter is used to maintain correct valve clearance, mainly taking into account the difference between the elongation of the cylinder head due to heat and the elongation of the lateral sides of the valve. However, in the past, this hydraulic lifter itself was constructed as a separate body from the rocker arm.
, is arranged so that one end contacts the cam and interlocks with the other end of the rocker arm, so that Ti,
There was a drawback that installation within the limited width of the engine room of a vehicle was troublesome.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to reduce the above-mentioned drawbacks of the prior art by incorporating the hydraulic lifter itself into the rocker arm.

In the valve operating mechanism of the present invention, a hydraulic lifter inserted into the rocker arm is disposed directly on the rocker arm to form a pressure chamber together with the rocker arm, and a plunger that interlocks with the valve stem operates only on the pressure chamber. It has a check valve that allows the oil flow]ffl, a spring that biases the plunger toward the valve stem, and a leak clearance formed between the plunger and the rocker arm, and a leak clearance that is formed in the rocker arm. It has a reservoir room,
The reservoir chamber has an inlet for working oil in its upper part and an outlet leading to the pressure chamber in its lower part.
installed in the rocker arm and placed at 7'1:
The desired goal can be achieved.

In the valve operating mechanism according to the present invention, the hydraulic plunger is directly disposed on the rocker arm as described above, so there is no need for a body for the hydraulic lifter, and the number of parts can be reduced, resulting in lower costs. In addition, since it can be formed on the rocker arm at a location different from the oil/sweat lifter in the reservoir chamber C, it is effective to downsize the hydraulic lifter that is incorporated into the rocker arm. Although there is an inlet for oil and an outlet for working oil in the lower part, even if the engine on the opposite shore is stopped due to the compressed hydraulic lifter, there is still a lot of working oil in the reservoir chamber. When starting the internal combustion engine, there is an effect of preventing the occurrence of a single sound due to tappet noise or the like due to insufficient supply of In oil to the pressure chamber.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

(7) 'AA is in contact with the cam 13 supported by the camshaft 12, and the rotation of the camshaft 12 causes the rocker arm to 11 swings around the rocker arm shaft 14. A hydraulic lifter 15 incorporated in the other end of the rocker arm cooperates with a valve stem 17 that receives the biasing force of a spring 16, and opens and closes an intake and exhaust valve 18 in accordance with the movement of the rocker arm 11.

2rT1. is shown in detail in FIG. As shown, the hydraulic lifter 15 has a plunger 21 which is directly disposed on the body 19 of the rocker arm 11 and generates a pressure ♀2° together with the body 19 of the rocker arm 11. Pressure chamber 20G goblin gear 2
A passage 221 formed in the main body 19 can communicate with an outlet 25 of a cylindrical reservoir chamber 24 provided in the main body 19 in the vicinity of the hydraulic lifter 15G, through a passage 23 formed in the main body 19. This communication is controlled by a ball-shaped check valve 26 located within the pressure chamber 20. The other end of a small spring 28 with a specific axial biasing force, one end of which is locked in the retainer 27 of the check valve 26, is formed on the plunger 21. The biasing point J] is biased in the direction of cutting off communication between the chamber 24, and therefore, the flow of working oil only from the reservoir chamber 24 to the pressure chamber 20 is allowed. The plunger 2] is biased downward as shown in the figure through the retainer 27 by the other end of the spring 30, which has a relatively large biasing force and is engaged with one end of the main body 196J.
The lower prong 81 interlocks with the valve stem 17. When the plunger 21 moves upward and the pressure chamber 20 becomes compressed,
The working oil in the pressure chamber 20 is distributed between the plunger 2 and the main body 1.
The leakage air 2' is sent to the reservoir chamber 24, oil pan, etc. through the leak clearance 82 formed during the period 9.

The reservoir chamber 24-r is covered by a blind plug 88 fixed to the main body 19. In the upper part of the reservoir chamber 24, an inlet 84 for operating oil is formed in the main body 19. It is connected to an operating oil source such as an oil pump (not shown) via a groove 36.87 formed in the rocker end shaft 14.

As described above, the ff7B valve train mechanism uses the rocker arm 1 by the camshaft 12 which is rotated between the internal combustion parts.
1 is swung, the plunger 21 contracts or extends with respect to the main body 19 of the rocker arm 11, and the hydraulic lifter 15 repeatedly expands and contracts by a predetermined dimension, thereby maintaining the valve clearance of the valve mechanism at zero. be. In the above, when the pressure chamber 20 is compressed, the check valve 26 is closed and the oil in the pressure chamber 20 flows out through the leak clearance 82, and when the pressure chamber 20 is expanded, the check valve 26 is opened. Working oil flows into the pressure chamber 20 .

In the above embodiment, the reservoir chamber is arranged on one side of the hydraulic lifter, but it may be provided around the hydraulic lifter so as to surround the hydraulic pressure 11 lid.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway Mi diagram of a valve train according to the present invention, and FIG. 2 is an enlarged sectional view of the main part of FIG. 1. 10... Valve mechanism, 11... Rocker arm, 12.
...Camshaft, 13...Cam, 14...Rocker arm riil! +, 15... Hydraulic lifter, 17.
,・Valve stem, 20...Pressure chamber, 21...Plunger, 24-...Reservoir chamber, 25...Outlet, 26
...Check valve, 30...Sbringe, 82...
Leak clearance, 34... Entrance Patent applicant Aisin Seiki Co., Ltd. Figure 1 8 33 Figure 2

Claims (1)

[Claims] It has a rocker arm incorporating a hydraulic pressure +17 in contact with the valve stem which receives the biasing force of the spring at one end thereof, and the hydraulic pressure switch is directly disposed on the rocker arm. A plunger which is formed together with the rocker arm and is interlocked with the valve stem described in 1), a check valve that allows the flow of operating oil only to the pressure shown in 0'i7, and the plunger 1 if'
86 valve stem, and a leak clearance formed between the plunger and the rocker arm, and the rocker arm is formed so as to be able to communicate with the i7+ pressure chamber via the check valve. The reservoir chamber has an inlet for working oil in its upper part and an outlet leading to the force chamber in its lower part. .