JPS63167014A - Hydraulic circuit of valve action time control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the responsiveness of an actuator by letting lubricating oil to flow through an oil path disposed in a rocker shaft for driving the actua tor adapted to connect and disconnect rocker arms even during medium-low speed operation of an engine. CONSTITUTION:During medium-low speed operation of an engine, a spool 32 of a solenoid valve 30 is placed at a position shown in the drawing, so that the first and second ports 35, 38 communicate with each other. Therefore lubri cating oil flows through oil paths 39, 16 in order to lubricate a cam for low speed. A part of the lubricating oil flows from the first leak passage 54 connecting the first end third ports 35, 40 in an oil path 42 in a rocker shaft 8 through an oil path 41. A part of the lubricating oil flows through an oil path 44, an orifice 45 and an oil path 17 in order, and then it lubricates a cam for high speed or the like. Since a little lubricating oil flows through an oil path 42 even during medium-low speed operation, the lubricating oil can be heated so that the first to third rocker arms 5-7 can be connected favorably by a actuator 43.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a hydraulic circuit for a valve operation timing control device that varies the operation timing of an intake valve or an exhaust valve of an internal combustion engine.

<Conventional technology> Increase the output of the internal combustion engine to i+! As one method for controlling I, for example, as disclosed in the specification of JP-A-61-19911, by making the valve operating timing variable between low speed and high speed operation of the engine, Techniques are known that improve the efficiency with which air-fuel mixture is charged into the combustion chamber over a wide operating range. Such a valve operation timing control device uses the inside of the rocker shirt l~ as an oil passage, and supplies hydraulic pressure from the engine to a coupling mechanism consisting of a hydraulic actuator built into the rocker arm to switch the valve. It is structured to do so.

The hydraulic circuit for supplying this oil pressure is closed in the engine's medium and low speed range, but opens when the engine speed reaches a predetermined set speed, and lubricating oil is pumped from the engine side to the actuator. .

For this reason, when the oil is cold, the lubricating oil in the oil passage has a low temperature, so its fluidity decreases, and even if an activation signal for valve switching is issued, the hydraulic response is poor, making it difficult for the valve to switch smoothly. The problem was that it wasn't done.

<Problems to be Solved by the Invention> Therefore, an object of the present invention is to provide a valve timing control device for an internal combustion engine with excellent responsiveness of hydraulic pressure even in cold conditions, and to ensure smooth valve switching at all times. The purpose of the present invention is to provide a hydraulic circuit that can be used for various purposes.

Means for Solving Problems> According to the present invention, the above-mentioned object is achieved by a cam that rotates synchronously with the crankshaft. In order to reach the actuator provided in the rocker arm for opening the intake valve or exhaust valve, which is driven in the valve closing direction and is biased in the valve closing direction, an oil passage installed in the rocker shaft that pivotally supports the rocker arm is connected. A hydraulic circuit for a valve timing control device for an internal combustion engine in which hydraulic pressure is applied from one end, the other end of the oil passage communicating with an open end via an orifice. This can be accomplished quickly by providing a hydraulic circuit for a valve timing control device.

<Operation> With this arrangement, the lubricating oil always flows through the hydraulic circuit from the engine side, so that the temperature of the lubricating oil in the oil passage can be easily raised even when the engine is cold.

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

FIG. 1 shows a valve train for an internal combustion engine to which a hydraulic circuit according to the present invention is applied. In this valve mechanism, the operating timing of the valve is variable in the medium-low speed range and the high-speed range of the engine, and a pair of intake valves 1a and 1b provided in the engine body (not shown) are connected to the crankshaft. Cam shirt i driven synchronously at 1/2 speed of (not shown)
A pair of low-speed cams 3a, 3b and a single high-speed cam 4 with an open cross section are integrally provided in ~2, and a cam hood that engages with these cams 3a, 3b, 4 to perform a swinging motion. The opening/closing operation is performed by working with the first to thirtieth lever arms 5 to 7 as the t-lower. Further, this engine is equipped with a pair of exhaust valves (not shown), which are driven to open and close in the same manner as the intake valves 1a and 1b described above.

The first to thirtieth lever arms 5 to 7 are pivotably supported adjacent to each other in a rocker foot 8 which is fixed below the camshaft 2 in parallel to the camshaft. The 30th lever arm 5.7 has basically the same shape, its base is pivotally supported by the rocker shaft 8, and each of its free ends extends above both intake valves 1a, 1b.

The free ends of these double-ended hook arms 5.7 are provided with tappets 1 to screws 9a and 9 that come into contact with the upper ends of each intake valve 1a and 1b.
b are screwed so that they can move forward and backward, and each of the tappets 1 to screws are prevented from loosening by lock nuts 10a and 10b, respectively.

The 20th claw arm 6 is connected to the first and 30th claw arms 5.
7 and is pivotally supported on a rocker shaft 8, and slightly extends from the rocker shaft 8 toward the middle of both intake valves 1a11b. A cam slipper 6a that slides on the high-speed cam 4 is formed on the upper surface of the 20th lever arm 6, and the upper end surface of the lost motion spring 11 is in contact with the lower end of the cam slipper 6a. This lost motion spring 11
has a built-in coil spring, high-speed cam 4 and cam slipper 6
This is for applying an upward biasing force to the 20th lug arm 6 so that it is always in sliding contact with the lug arm 6.

The camshaft 2 is rotatably supported above the engine body, and includes low-speed cams 3a and 3b formed in a cam profile having a relatively small lift that is suitable for low-speed engine operation, and low-speed cams 3a and 3b that are suitable for high-speed engine operation. A high-speed cam 4 formed in a cam profile having a larger lifting height over a wider angle than the low-speed cams 3a and 3b is integrally connected to the high-speed cam 4. The low-speed cams 3a, 3b come into sliding contact with cam slippers 5a, 7a formed on the upper surfaces of the first and thirtieth lever arms 5.7, respectively, on their outer peripheral surfaces. In addition, these first to 30th arm arms 5 to 7
A connecting device is installed in a hole drilled through the center of these parts in parallel with the rotary shaft It is possible to switch between the state of angular displacement and 1q.

At the top of both intake valves 1a and 1b, a retainer 12a,
12b are provided respectively, and these retainers 12
Both intake valves 1a are installed between a and 12b and the engine body.
, a valve spring 13a surrounding the stem portion of 1b,
13b is interposed, and biases both intake valves 1a and 1b toward the valve closing direction, respectively.

An oil supply pipe 14 for the low-speed cam 3a13 and an oil supply pipe 15 for the high-speed cam 4 are disposed above the camshaft 2. Lubricating oil is supplied from

Injection holes 18a and 18b that open above the low-speed cams 3a and 3b are bored in the outer circumferential surface of the oil supply pipe 14, and the lubricating oil supplied through the oil passage 16 flows into each low-speed cam in a Java manner. 3a and 3b.

The other oil supply pipe 15 has two pipes perpendicular to its axial direction.
Two branch pipes 23 and 24 are connected, and their free ends 23a and 24a extend across the high-speed cam 4 to a position facing the sliding surface between the cam and the cam slipper 6a. There is. A nozzle 25 that opens toward the sliding surface of the high-speed cam 4 and the cam slipper 6a is attached to the free end 23a of the branch pipe 23. The lubricating oil is injected in the same direction as the rotation direction A of 4. Similarly, the free end 24a of the other branch pipe 24 is accessed from the opposite side of the cam 4!
A nozzle 26 that opens toward the covered surface is attached,
Lubricating oil is injected from the rear side of the cam 4 in a direction opposite to the rotational direction A of the cam 4. Furthermore, the lubricating oil supplied through the oil passage 17 includes a passage 19a connected to the oil supply pipe 15,
The journals 20a and 20b, which are integrally formed on the camshaft 2 via the camshaft 19b, are also flattered.

FIG. 2 schematically shows a hydraulic circuit applied to a valve timing control device for a four-cylinder internal combustion engine equipped with the valve operating mechanism shown in FIG. In the electromagnetic valve 30, a spool 32 that slides into a guide hole 31 is urged by a spring 33 to the position shown in the figure, and is attracted upward when a solenoid 34 is energized. The first port 35 is an inlet for hydraulic pressure, and is connected to the engine oil pump 3 through an oil passage 36.
It is connected to 7. The second port 38 communicates via an oil passage 39 with an oil passage 16 for supplying oil to the low-speed cams 3a and 3b. The third port 40 communicates with an oil passage 42 provided inside the rocker shaft 8 via an oil passage 41, and supplies hydraulic pressure to a coupling mechanism 43 consisting of a hydraulic actuator provided inside the rocker arm each day. supply and the second
The zero tension arm 6 is lubricated. An oil passage 44 is connected to the rear end of the oil passage 42, and an orifice 45 is provided in the oil passage 44, and an oil passage 17 for supplying oil to the high-speed cam 4.
is connected to. The oil passage 17 also lubricates the journals 20a to 20e of the camshaft 2 via passages 19a to 19e.

A drain hole 46 is bored at the lower end of the guide hole 31, so that lubricating oil leaking from the gap between the spool 32 and the guide hole 31 flows into the cylinder head (not shown) without staying in the guide hole 31. It's starting to swell.

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

When the engine is operating at medium to low speeds, the spool 32 is in the position shown in the figure, so the first port 35 and the second port 38 communicate with each other, and lubricating oil supplied from the engine side flows into the oil path 16 via the oil path 39. It is supplied to lubricate the low speed cams 3a and 3b. The spool 32 is provided with a first leak passage 54 that communicates the first port 35 and the third bow 1-40 at the above-mentioned position, and a portion of the lubricating oil supplied from the engine side is formed in the spool 32. The oil flows through an oil path 41 to an oil path 42 inside the rocker shirt 1-8. When the lubricating oil supplied to the oil passage 42 passes through the oil passage 44, it is throttled by an orifice 45 and flows slightly toward the oil passage 17 to lubricate the high-speed cam 4 and the cam slipper 6a. . In this way, a slight flow of lubricating oil is formed in the oil passage 42 inside the rocker shaft 8 even when the engine is operating at low to medium speeds.

During high-speed operation of the engine, the spool 32 is sucked upward by the solenoid 33, so the first port 35 and the third port 40 communicate with each other, and the lubricating oil supplied from the engine is mainly supplied to the oil passage inside the rocker shaft 8. 42. As a result, the actuator 43 is driven, the first to thirtieth lever arms 5 to 7 are integrally connected, and the valves are switched. This actuator 43 is a known one disclosed in, for example, Japanese Patent Laid-Open No. 19911/1983. The lubricating oil supplied to the oil passage 42 flows into the oil passage 17 with its flow rate adjusted by the orifice 45, and is then passed through the high-speed cam 4, the cam slipper 6a, and the journals 20a to 2.
Lubricate 0e.

Further, the solenoid valve 30 is in the first port 35 in the energized state.
Since the second leak passage 55 that communicates with the first port 35 and the second ports 1 to 38 is M'AC, a portion of the lubricating oil flows from the first port 35 to the second port 38 even in this spool position. , is supplied to the oil passage 16 via the oil passage 39, and lubricates the low-speed cams 3a, 3b and the cam slippers 5a, 7a.

In the above embodiment, the lubricating oil flowing out from the rear end of the oil passage 42 through the orifice 45 is used to lubricate the high-speed cam 4, the cam slipper 6a, and the journal. It can also be used to oil the low-speed cams 3a, 3b, etc.

<Effects of the Invention> As described above, according to the present invention, the rocker arms can be connected and
An orifice is provided at the rear end of the oil passage provided in the rocker shaft to drive the actuator to be released, and lubricating oil always flows through the oil passage from the engine side even when the engine is operating at medium to low speeds. This makes it possible to raise the temperature of the lubricating oil in the core oil passage even when it is cold, thereby significantly improving the responsiveness of valve switching. In addition, by using the lubricating oil leaked from the orifice to lubricate each cam, rocker arm, or V-nal, the lubricating oil can be used effectively.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically illustrating a valve train for an internal combustion engine to which the present invention is applied. FIG. 2 is an explanatory diagram showing the hydraulic circuit of the present invention. 1811b...Intake pulp 2...Camshaft 3a, 3b...Low speed cam 4...High speed cam 5...10th lever arm 5
a... Cam slipper 6... 20th lug arm 6a
...Cam slipper 7...30th lug arm 7a.
...Cam slipper 8...Rocker shaft 9a, 9b
...Tappet screws 10a, 10b...Lock nuts 11...Lost motion springs 12a, 12b
...Retainers 13a, 13b...Valve springs 14.15...
・Oil supply pipe 16.17...Oil passage 18a, 18b-...
Injection holes 198-19e...Passages 20a-20e...Journal 23...Branch pipe 23a...Free end 24...
...Branch pipe 24a...Free end 25.26.
... Nozzle 30 ... Solenoid valve 31 ... Guide hole
32...Spool 33...Spring 34.
...Solenoid 35...First port 36...Oil passage 37...Oil pump 38...Second port 39
...Oil channel 40...3rd boat 4L42.
...Oil passage 43...Connection mechanism 44...Oil passage
45... Orifice 46... Drain hole 5
4...First leak passage 55...Second leak passage

Claims (2)

[Claims] (1) The rocker arm is pivoted so as to reach the actuator provided on the rocker arm for opening the intake valve or exhaust valve, which is oscillated by a cam that rotates in synchronization with the crankshaft and is biased in the valve-closing direction. A hydraulic circuit for a valve actuation timing control device for an internal combustion engine, in which hydraulic pressure is applied from one end of an oil passage installed in a supported rocker shaft, wherein the other end of the oil passage is connected to an open end via an orifice. A hydraulic circuit for a valve timing control device, characterized in that the hydraulic circuit is in communication with the valve timing control device. (2) The open end is comprised of an oil supply passage for lubricating the cam, a camshaft or journal that rotates integrally with the cam, or the rocker arm. Hydraulic circuit for valve timing control device.