JPS63167011A - Hydraulic circuit of valve train for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a valve mechanism for an internal combustion engine that has a plurality of intake valves or exhaust valves that are driven via a rocker arm by a cam that rotates in synchronization with a crankshaft. related to hydraulic circuits.

<Conventional technology> Regarding the above-mentioned internal combustion engine, in order to optimize the intake and exhaust efficiency over the entire rotation range from low speed to high speed, the number of activated intake and exhaust valves is changed according to the engine speed. Valve actuating body locking mechanisms are known. In addition, in Japanese Patent Application Laid-open No. 19911/1983 by the applicant of the present application, by changing the timing of operation of a valve between low speed and high speed operation of the engine, mixing into the combustion chamber over a wide operating range is disclosed. Methods have been proposed to improve the air filling efficiency.

These valve-like grooves open and close hydraulic circuits by operating electromagnetic valves in response to engine rotational speeds, moving pistons built into one rocker arm to connect or connect adjacent rocker arms. When the valve is released, the valves are switched by operating the two lever arms together or separately. On the other hand, it is important to provide sufficient lubrication to the cam and the rocker arm that contacts it in response to valve switching.

A fixed amount of lubricating oil held in the engine is pumped into these hydraulic circuits and lubricating oil passages by an oil pump, but if hydraulic pressure is supplied and controlled separately for each, the oil supply system will be ! As the fuel becomes more complicated, there is a risk that sufficient fuel cannot be supplied to each fuel. Therefore, the necessary and sufficient hydraulic pressure is always supplied to ensure valve switching operation.
In order to achieve sufficient rrU slippage, it is necessary to configure the hydraulic circuit in consideration of economy so that lubricating oil can be used as effectively as possible, and to easily control the hydraulic circuit so as to achieve 1q.

<Problems to be Solved by the Invention> Therefore, an object of the present invention is to effectively use the hydraulic pressure supplied from the engine side to ensure that the valves are switched in accordance with the engine rotational speed on the same day. First, it is an object of the present invention to provide a hydraulic circuit for a valve mechanism for an internal combustion engine, in which the cams are supplied with necessary and sufficient oil and can be easily controlled.

According to the present invention, a plurality of intake valves or exhaust valves that are biased in the valve closing direction, and a plurality of intake valves or exhaust valves corresponding to the intake valves or exhaust valves are A connecting means for selectively connecting or disconnecting a plurality of rocker arms that are pivotally supported on a rocker shaft and that are driven to swing by a cam that rotates in synchronization with the crankshaft, and the adjacent rocker arms by the action of hydraulic pressure. and a hydraulic circuit for supplying hydraulic pressure to the connecting means, and an oil supply passage for lubricating the cam, in which the hydraulic circuit and the oil supply passage are connected in series via a throttle means. The lubricant is connected to and supplied from the engine side so that i1η lubricant oil supplied from the engine side flows from the oil supply passage side to the hydraulic circuit side when the engine is running at low speed, and from the hydraulic circuit side to the oil supply passage side when the engine is running at high speed. This is achieved by providing a hydraulic circuit for a valve mechanism for an internal combustion engine, characterized in that it is equipped with a switching means for switching the direction of flow of lubricating oil.

<Operation> By doing this, by switching the direction of lubricating oil supplied from the engine side with a single control operation, the valve can be reliably switched between high-speed and low-speed engine operation. At the same time, the cam can be appropriately lubricated in response to this valve switching.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 schematically shows a valve train 11 structure of an internal combustion engine to which a hydraulic circuit according to the present invention is applied. A pair of intake valves 1.2 provided in the engine body (not shown) are connected to a spring 3.
．． 4 in the valve closing direction. Both of these intake valves 1.2 are connected to a cam 6 having an egg-shaped cross-section and parallel to the camshaft 5, which is integrally provided with a camshaft 5 that is synchronously driven at a rotation speed of 1/2 of a crankshaft (not shown). The opening/closing operation is performed by a rocker arm 8.9 which is swingably supported by a rocker shaft 7. This engine also has a pair of exhaust valves (not shown).
is provided, and is driven to open and close in the same manner as the intake valve 1.2 described above.

The double-ended hook arms 8.9 are arranged adjacent to each other, and tappet screws 10 and 11 that abut the upper ends of the respective valves 1.2 move forward and backward at the free ends that extend above both the intake valves 1.2. Each tappet screw 10, 11 is secured by a lock nut 12, 13. Further, a cam slipper 14 is formed on the upper surface of the tenth claw arm 8 and is in contact with the cam 6 once. Furthermore, an oil supply pipe 26 having an oil supply passage 25 inside is arranged above the camshaft 5, and lubricating oil is directed toward the cam 6 in a Java style from an injection hole 27 bored above the cam 6. It is designed to be sprayed.

As shown in FIG. 2, the double-ended hook arms 8 and 9 have a built-in connecting device that connects or disconnects them depending on the engine speed.

This coupling device includes a piston 16 accommodated so as to be movable in a first guide hole 15 bored inside a tenth lever arm 8, and a twentieth lever arm 9 corresponding to the guide hole 15.
The coil spring 2 is inserted into the second guide hole 21 bored inside the coil spring 2.
3, the stopper 22 is biased toward the tenth claw arm B side by the stopper 22.

A hydraulic chamber 1B is defined on the bottom side of the first guide hole 15, and is always in communication with an oil passage 20 provided in the rocker shaft 7 via a passage 19.

When a predetermined hydraulic pressure is supplied from the engine side to the hydraulic chamber 19 via the oil passage 20, the piston 16 moves toward the 20th lever arm 9.
It is pushed out to the side and enters the second guide hole 21 against the biasing force of the spring 23 while pressing the stopper 22, thereby integrally connecting the tenth claw arm 8 and the twentieth claw arm 9. When the hydraulic pressure acting on the hydraulic chamber 18 is released, the piston 16 is pushed back into the first guide hole 15 by the biasing force of the spring 23, and the double-ended hook arms 8.9 are again separated so as to be able to be relatively angularly displaced. In this way, the valves are switched between when the engine is operating at medium to low speeds and when operating at high speeds.

As clearly shown in FIG. 2, lubricating oil stored in an oil tank 30 is pumped by an oil pump 31 toward a flow rate adjustment switching valve 32. This flow rate adjustment switching valve 32
is composed of a spool valve 33 and a variable orifice 34, and the spool valve 33 has first bows 1 to 35, which are usually inlets for hydraulic pressure, communicating with a second port 36, and a solenoid 37.
When energized, the first port 35 and the third boat 3B communicate with each other. A variable orifice 34 is provided on the downstream side of the second port 36 and communicates with the cam oil supply passage 25.The third port 38 communicates with the oil passage 20 in the cam oil supply passage 25. The oil supply passage 25 and the oil passage 20 are connected in series via an A refit 39.

The operating procedure of this hydraulic circuit will be explained below.

When the engine is running at medium to low speed, the first part of the spool valve 33
Since the bow i~35 and the second port 36 are in communication,
Lubricating oil is pumped from the engine side through a variable orifice 34
After adjusting the flow rate, the oil flows into the oil supply passage 25 to lubricate the cam 6 and the cam slipper 14, and at the same time, the flow rate is further adjusted by the A refill 39, and then introduced into the oil passage 20.

In this way, the variable orifice 34 is provided on the upstream side of the oil supply passage 25.
By providing the fixed orifice 39 between the oil supply passage 25 and the oil passage 20, the amount of oil supplied to the cam 6 and the oil pressure within the oil passage 20 can be controlled. That is, if the pressure of the lubricating oil pumped from the engine side is Po, the oil pressure in the oil supply passage 25 is P2, and the oil pressure in the oil passage 20 is P2, then P2<P* must be satisfied. However, even if the oil pressure Po supplied from the engine increases with the engine speed, P2 can always be maintained below P* by adjusting the variable orifice 34 (one line margin).

During high-speed operation of the engine, the solenoid 37 is operated to communicate the first boat 35 and the third port 3B, and the hydraulic pressure supplied from the engine side is supplied directly to the oil passage 20. In this case, since the oil pressure Po=P2>P* is established, the piston 16 is driven, the tenth claw arm 8 and the twentieth claw arm 9 are connected, and the valves are switched. The lubricating oil supplied to the oil passage 20 has its flow rate adjusted by the orifice 39 and is supplied to the cam oil supply passage 25 to lubricate the cam 6 and the cam slipper 14.

<Effects of the Invention> As described above, according to the present invention, the cam oil supply passage and the oil passage for the coupling device are connected in series via the orifice,
By using a spool valve to switch the flow direction of lubricating oil supplied from the engine side, it is possible to simultaneously control the cam lubricating system and the operation of the coupling device with a single control operation, and to effectively utilize the lubricating oil. This can be used to supply the necessary and sufficient oil to the cam depending on the operating conditions of the engine.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a valve train to which the present invention is applied. FIG. 2 is a hydraulic system diagram showing a hydraulic circuit according to the present invention. 1.2...Intake valve 3.4...Spring 5...Camshaft 6...Cam 7...Rocker shaft
8... 10th Tsuka Arm 9... 20th Tsuka Arm 1
0,11... Tappet screw 12.13... Lock nut 14... Cam slipper 15... First guide hole 16
... Piston 18 ... Hydraulic chamber 19 ... Passage 20 ... Oil passage 21 ... Second guide hole 2
2...Stopper 23...Coil spring 25...
Oil supply passage 26...oil supply pipe 27...injection hole 3
0... Oil tank 31... Oil pump 32.
...Flow rate adjustment switching valve 33...Spool valve 34...Variable A refit 35...First boat 36...Second port 37...Solenoid 38...Third port
39...A Lifts Special Edition Applicant: U Giken Kogyo Co., Ltd. Representative Patent Attorney Yo Oshima - Figure 1 Figure 2

Claims (1)

[Scope of Claims] A plurality of intake valves or exhaust valves biased in the valve closing direction, and a plurality of intake valves or exhaust valves that are pivotably supported on a rocker shaft in correspondence with the intake valves or exhaust valves, and that rotate synchronously with the crankshaft. a plurality of rocker arms that are swing-driven by cams, a connecting means that can selectively connect or disconnect adjacent rocker arms by the action of hydraulic pressure, a hydraulic circuit that supplies hydraulic pressure to the connecting means, and a hydraulic circuit that lubricates the cam. In the valve operating mechanism for an internal combustion engine, the hydraulic circuit and the oil supply passage are connected in series through a throttle means, and the lubricating oil supplied from the engine side is used to control the low speed operation of the engine. The lubricating oil is characterized by comprising a switching means for switching the direction of flow of the lubricating oil so that the lubricating oil flows from the oil supply passage side to the hydraulic circuit side at times, and from the hydraulic circuit side to the oil supply passage side during high-speed operation. Hydraulic circuit for valve train for internal combustion engine.