JPS63167009A - Valve system of internal combustion engine - Google Patents

Abstract

PURPOSE:To supply the required minimum quantity of lubricating oil to each lubricating oil path and to reduce an oil pressure supply source in size by providing lubricating oil paths for low speed and high speed, and disposing a control valve for throttling the quantity of lubricating oil during low-speed operation of an engine between each lubricating oil path and the oil pressure supply source. CONSTITUTION:During low-speed operation of an engine, a plunger 64 of a control valve 56 is placed at a position shown in the drawing and input and output ports 65, 66 are communicated with each other through a restriction 70, so that oil pressure from an oil pressure supply source 54 is throttled to be supplied to an oil pressure supply path 41. Oil pressure in the oil pressure supply path 41 is further throttled by a throttle 5 to be supplied to a lubricating oil path 26 for high speed, so that low-pressure lubricating oil is jetted from a jet pipe 28. Accordingly oil pressure in an oil pressure chamber 39 becomes low, so that switching pins 33-35 are returned by a return spring 36 to put rocker arms 7-9 in the state of disconnection. Oil pressure from the oil pressure supply source 54 is throttled by a restriction 71 to be supplied to a lubricating oil path 25 for low speed, and a small quantity of lubricating oil is jetted from a jet nozzle 27. During high-speed operation of the engine, a control valve 56 is adapted to limit the quantity of oil circulating between the oil pressure supply source and the lubricating oil path for low speed to the small quantity to be communicated with each other.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to a low-speed cam or a perfectly circular protuberance that corresponds to the operation mode of an intake valve or an exhaust valve during low-speed operation of an engine. and a high-speed cam that corresponds to the operation mode of the intake valve or exhaust valve during high-speed operation of the engine, is provided on the camshaft,
A cam follower that slides into low-speed cam or raised portion,
A connection switching mechanism is provided between the cam follower, which is biased by the elastic biasing means and slides into contact with the high-speed cam, and which switches the connection and disconnection of the cam follower to drive the intake valve or exhaust valve to open or close depending on the operating state of the engine. The present invention relates to a valve train for an internal combustion engine in which a valve train is provided.

(2) Prior Art Conventionally, such a valve train has been developed, for example, in Japanese Patent Application Laid-open No. 61-1991.
) is publicly known.

(3) Problems to be Solved by the Invention In such a valve train, the sliding contact portion between the cam or the raised portion and the cam follower is lubricated (lubricating oil is supplied to the sliding contact portion, but conventionally, lubricating oil is supplied to the sliding contact portion). However, when the engine is running at high speed, the sliding load on the sliding contact area between the low-speed cam or the protrusion and the cam follower is relatively small, and The sliding load on the sliding contact parts of high-speed cams and cam followers is relatively small when the engine is running at low speed.Therefore, if the amount of lubricant supplied to each sliding contact part is controlled according to the engine operating condition, a relatively small amount of lubricant can be supplied to the sliding contact parts of the high-speed cam and cam follower. It will be possible to achieve sufficient lubrication with lubricating oil, and it will be possible to downsize and save energy in hydraulic supply sources such as oil pumps.

The present invention has been made in view of the above circumstances, and is capable of supplying a minimum amount of lubricating oil to the sliding contact portion between the cam or the protruding portion and the cam follower according to the operating condition of the engine, thereby providing a hydraulic supply source. An object of the present invention is to provide a valve operating system for an internal combustion engine that is designed to reduce the size and save energy.

B3 Structure of the Invention fll Means for Solving the Problems According to the present invention, there is provided a low-speed lubricating oil passage for supplying lubricating oil toward the sliding contact portion between the low-speed cam or the protrusion and the cam follower, and the high-speed lubricating oil passage. A high-speed lubricating oil passage for supplying lubricating oil to the sliding parts of the cam and cam follower is provided independently from each other, and a low-speed lubricating oil passage and a high-speed lubricating oil passage are connected to the hydraulic supply source. During low-speed operation of the engine, the amount of circulating oil is reduced to provide communication between the high-speed lubricating oil passage and the hydraulic pressure supply source over the entire operating range of the engine, and at least one communication between the low-speed lubricating oil passage and the hydraulic pressure supply source is established. A control valve is provided that is configured to be in communication during low speed operation of the engine.

(2) Effect According to the above configuration, when the engine is operating at low speed, lubricating oil is supplied to the sliding contact area between the low-speed cam or the protrusion and the cam follower as the sliding load increases, and when the engine is operating at low speed, During operation, lubricating oil is supplied to the sliding contact area between the high-speed cam and the cam follower as the sliding load increases.
Moreover, since the cam follower is always in elastic sliding contact with the high-speed cam, a small amount of lubricant is supplied to the sliding contact parts of the high-speed cam and cam follower even when the engine is running at low speed, and the minimum amount of lubrication is required. Sufficient lubrication is provided with oil.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. First, in FIGS. 1, 2 and 3, a pair of intake valves 1a provided on the sides of the engine body are shown.

1b is a low-speed cam 3, 3 and a high-speed cam 5 that are integrally provided on a camshaft 2 that is rotationally driven from the engine's crankshaft at a reduction ratio of 1/2, and a rocker shaft 6 that is parallel to the camshaft 2. 1st, 2nd and 30th arm as a cam follower pivoted to ? , 8.9 and the connection switching mechanism 10 provided between each of the rocker arms 7 to 9 to open and close.

The camshaft 2 is rotatably arranged above the engine body E, and the cams 3, 3 for both image speeds are connected to each intake valve 1a, lb
The high-speed cam 5 is integrated into the camshaft 2 in response to
is integrated into the camshaft 2 between the two image speed cams 3, 3. Each of the low-speed cams 3.3 has a shape suitable for low-speed operation of the engine, and each has a base interior 3a and a high portion 3b that projects radially outward from the base interior 3a. The high-speed cam 5 has a shape suitable for high-speed operation of the engine, and has an inner base 5a and a high portion 5b having a larger protrusion amount and center angle range than the high portion 3b.

The rocker shaft 6 is fixedly arranged below the camshaft 2. This rocker shaft 6 has a first cam slipper 1) on its upper part that slides into contact with one of the low-speed cams 3.
The 20th hook arm 8 has a cam slipper 12 on its top that slides against the other low-speed cam 3, and the 30th hook arm 9 has a cam slipper 13 on its top that slides on the high-speed cam 5. They are respectively pivotally supported adjacent to the shaft 6 in the axial direction.

The first and 20th lever arms 7.8 have intake valves la and l.
b are interlocked and connected. That is, each intake valve 1a, lb
is biased in the valve-closing direction, that is, upward, by a valve spring 16-17 interposed between a flange 14-15 provided at its upper end and the engine body E, and the first and 20th lever arms Tappet screws 18.19, which abut the upper ends of the intake valves 1a, lb, are screwed to the tips of the valves 7.8 so as to be movable forward and backward.

The 30th lever arm 9 is biased by resilient biasing means 20 provided between it and the engine body E in a direction in which its cam slipper 13 is always in sliding contact with the high-speed cam 5.

The spring biasing means 20 includes a bottomed cylindrical glue lid 21 whose closed end is in contact with the lower surface of the 30th hook arm 9, and the lifter 2.
1 and a lifter spring 22 interposed between the engine body E, and the lifter 21 is slidably fitted into a bottomed hole 23 provided in the engine body E.

A passage forming body 24 is installed above the camshaft 2 between cam holders (not shown) that rotatably support the camshaft 2, and a low speed lubricating oil passage 25 is provided in the passage forming body 24. and a high-speed lubricating oil passage 26 are drilled independently and parallel to each other. Moreover, the jet hole 27 communicating with the low-speed lubricating oil passage 25 is connected to the low-speed cam 3.3 and the cam slipper 1). It is bored in the lower part of the passage forming body 24 at a position corresponding to the sliding contact portion 12. Furthermore, a pair of lubricating oil spouting pipes 28 arranged to spout lubricating oil from both sides of the camshaft 2 toward the sliding contact portions of the high-speed cam 5 and the cam slipper 13 communicate with the high-speed lubricating oil passage 26. It is connected to the passage forming body 24 .

Referring also to FIG. 4, the connection switching mechanism 10 connects a first switching pin 33 that can connect between the first and 30th lever arms 7.9 and between the third and 20th lever arms 9 and 8. the second switching pin 34 and the first and second switching pins 3
3.34, and a return spring 36 that urges each of the connecting pins 33 to 35 toward the disconnection side.

A first guide hole 37 parallel to the rocker shaft 6 is bored in the tenth lever arm 7.
The end opposite to the 30th hook arm 9 of 7 is the closing member 3
Blocked at 8. The first guide hole 37 has a first switching pin 3.
3 are slid together, and the closing member 3 is inserted into the first guide hole 37.
A hydraulic chamber 39 is defined between the first switching pin 8 and the first switching pin 33 . Further, the tenth lever arm 7 is provided with an oil passage 40 communicating with the hydraulic chamber 39, and the rocker shaft 6 is provided with an oil pressure supply passage 41. Oil passage 40 and hydraulic supply passage 41
are always in communication through a communication hole 42 formed in the side wall of the rocker shaft 6, regardless of the swinging state of the tenth hook arm 7. Further, the communication hole 42 is connected to the rocker shaft 6 and the first
It also functions to supply lubricating oil from the hydraulic pressure supply path 41 between the zero tension arms 7.

In the 30th hook arm 9, a second guide hole 43 having the same diameter as the first guide hole 37 is bored parallel to the rocker shaft 6 between both sides thereof. A second switching pin 34 having a length spanning the entire length is slid together.

A third guide hole 44 having the same diameter as the second guide hole 43 is bored in the 20th claw arm 8 in parallel with the rocker shaft 6, and the third guide hole 44 is opposite to the 30th claw arm 9. The side end is closed with a closing member 45.

A third switching pin 35 is slid into the third guide hole 44 , and a small-diameter shaft portion 46 coaxially connected to the third switching pin 35 moves into a guide hole 47 formed in the closing member 45 . It can be inserted freely. Moreover, the closing member 4 surrounds the shaft portion 46.
A return spring 36 is interposed between the switching pin 5 and the third switching pin 35. The return spring 36 urges the switching pins 33 to 35 that are in contact with each other toward the connection release side, that is, toward the hydraulic chamber 39 side.

Communication holes 48 and 49 are bored in the side wall of the rocker shaft 6 at portions corresponding to the third and 20th lever arms 9 and 8, and these communication holes 48 and 49 connect to the hydraulic pressure supply path 41.
lubricating oil from the rocker shaft 6 is supplied between the rocker shaft 6 and the third and twentieth claw arms 9.8.

In a state where high oil pressure is not supplied to the hydraulic chamber 39, each switching pin 33 to 35 is moved toward the connection release side by the spring force of the return spring 36, and in this state, the first and second switching pins 33, 34 The contact surfaces of the pins 34.35 are located at positions corresponding to between the first and 30th lever arms 7.9, and the contact surfaces of the second and third switching pins 34.35 are located between the third and 20th lever arms 9.
, 8, and the rocker arms 7-9 are not connected. Further, when high hydraulic pressure is supplied to the hydraulic chamber 39, each of the switching pins 33 to 35 moves in a direction away from the hydraulic chamber 39 against the spring force of the return spring 36, and the first switching pin 33 moves into the second guide hole 49. and the second switching pin 34
slides into the third guide hole 44 to connect each of the rocker arms 7 to 9.

The hydraulic pressure supply path 41 and the high-speed lubrication oil path 26 are communicated via an oil path 50 that has a throttle 51 in the middle, and the hydraulic pressure supplied to the hydraulic pressure supply path 41 is throttled by the throttle 51 to provide high-speed lubrication. The oil is supplied to the oil path 26.

Between the oil passage 52 connected to the oil pressure supply passage 41, the oil passage 53 connected to the low-speed lubricating oil passage 25, and the oil passage 55 connected to the oil pressure supply source 54, there is a control system that operates according to changes in the operating state of the engine. A valve 56 is interposed.

The control valve 56 includes a cylinder body 60 having three axially spaced annular recesses 57, 58, 59 on its inner surface.
A plunger 64 having three annular grooves 61, 62, 63 on its outer surface which are spaced apart in the axial direction is slid together. In the cylinder body 60, an input port 6 connected to the oil pressure supply source 54 via an oil passage 55 is bored corresponding to the annular recess 58, an output port 6 connected to the oil passage 52, and an output connected to the oil passage 53. A port lower is bored corresponding to the annular recesses 57 and 59.

The plunger 64 is slidably driven in the axial direction by a drive means (not shown) in response to changes in the operating state of the engine.When the engine is operating at low speed, the plunger 64 is in the position shown in FIG. During operation, the plunger 64 moves to the left as shown in FIG. The land 68 between the annular grooves 61 and 62 of this plunger 64 is in sliding contact with the inner surface of the cylinder body 60 between the annular recesses 57 and 58 when the engine is operating at low speed, and is located at a position corresponding to the annular recess 57 when the engine is operating at high speed. Also, the land 69 between the annular m62 and 63 is formed in the annular recesses 58 and 59 regardless of the operating state of the engine.
It is formed so as to be in sliding contact with the inner surface of the cylinder body 60 between. Moreover, the land 68 is provided with a throttle hole 70 that connects the annular grooves 61 and 62, and the land 69 is provided with a throttle hole 71 that has one end opened in the annular groove 62 and the other end opened on the outer surface of the land 69. The other end of this throttle hole 71 is opened on the outer surface of the land 68 so that it communicates with the annular recess 59 when the engine is operating at low speed, and is located at a position corresponding to the inner surface of the cylinder body 60 when the engine is operating at high speed. Ru. Further, on the inner surface of the cylinder body 60 between the annular recesses 58 and 59, a throttle notch 72 is provided that connects the other end of the throttle hole 71 and the annular recess 59 at the position of the plunger 64 during high-speed operation of the engine.

Next, the operation of this embodiment will be explained. When the engine is operated at low speed, the plunger 64 of the control valve 56 is in the position shown in the fourth figure. In this state, the input port 5 and the output port 6 communicate with each other via the throttle hole 70, so the hydraulic pressure from the hydraulic pressure supply source 54 is throttled and supplied to the hydraulic pressure supply path 41. Further, the oil pressure in the oil pressure supply path 41 is further throttled by a throttle 51 and supplied to the high-speed lubricating oil path 26, and the relatively low pressure lubricating oil is sent from the lubricating oil spouting pipe 28 to the high-speed cam 5 and the cam slipper 13. It is ejected towards the sliding contact area. As the hydraulic pressure throttled by the throttle hole 70 is ejected little by little from the lubricating oil spouting pipe 28, the hydraulic pressure in the hydraulic pressure supply path 41, that is, the hydraulic chamber 39, becomes a relatively low pressure, and in the connection switching mechanism 10, each switching pin 33-35 return spring 3
It is at the position where it has been moved to the maximum extent toward the hydraulic chamber 39 by the spring force of No. 6. In this state, the first and second switching pins 33°3
The abutment surface of No. 4 is located at a position corresponding to between the first and 30th lever arms 7°9, and the contact surface of No.
The abutment surface of is located at a position corresponding to between the third and twentieth hook arms 9 and 8. Therefore, each rocker arm 7-9 is in a state in which relative angular displacement is possible with respect to each other.

In such a disconnected state, the rotation of the camshaft 2 causes the first and twentieth claw arms 7.8 to engage the low-speed cam 3.
．． 3, and both intake valves 1a, lb open and close at a timing and lift amount depending on the shape of the low-speed cam 3.3.

At this time, the 30th lever arm 9 moves t8 in accordance with the sliding contact with the high-speed cam 5, but its swinging motion is
It has no effect on Tsuka Arm 7.8.

In addition, in this disconnected state, the input port lower 5 and the output port lower in the control valve 56 communicate with each other through the throttle hole 71, and the hydraulic pressure from the hydraulic pressure supply source 54 is throttled through the throttle hole 71, so that the low speed A relatively small amount of lubricating oil is supplied to the lubricating oil passage 25 and is ejected from the ejection hole 27 to the sliding contact portion of the low-speed cam 3.3 and the cam slipper 1), where the sliding load is relatively large. At this time, as mentioned above, a small amount of lubricating oil is also spouted from the lubricating oil spouting pipe 28 to the sliding contact portions of the high-speed cam 5 and the cam slipper 13, and is biased upward by the elastic biasing means 20. The sliding contact portion between the cam slipper 13 of the 30th latch arm 9 and the high-speed cam 5 is sufficiently lubricated, which can contribute to reducing the valve operating load.

When the engine is operated at high speed, the plunger 64 of the control valve 56 moves to the left as shown in FIG. Thereby, the annular recesses 57 and 58 communicate with each other via the annular groove 61. Therefore, a relatively high hydraulic pressure is supplied to the hydraulic pressure supply path 41, and the high hydraulic pressure is also supplied to the hydraulic chamber 39. For this reason,
In the connection switching mechanism 10, each of the switching pins 33 to 35 moves toward the connection position against the spring force of the return spring 36, and the first switching pin 33 slides into the second guide hole 43, and the second switching pin 3
4 slides into the third guide hole 44 and each rocker arm 7 to 9
are concatenated. At this time, the third
Since the amount of swing of the zero tension arm 9 is the largest, the first and 20th link arms 7°8 swing together with the 30th link arm 9, and both intake valves 1a and 1b have the timing and lift amount according to the shape of the high-speed cam 5. It opens and closes with.

During the connection operation of the connection switching mechanism 10, the sliding load increases because of the high-speed cam 5 and the cam slipper 1.
3, and oil that has been throttled by the throttle 51 and has a relatively low pressure is ejected from the lubricating oil spouting pipe 28 to the sliding contact portion. On the other hand, the low-speed lubricating oil passage 25 is supplied with hydraulic pressure throttled by the throttle hole 71 and the throttle notch 72, and a small amount of lubricating oil is spouted from the spout hole 27, but the low-speed cam 3.3
and cam slippers 1). Since the sliding contact portion 12 has a small sliding load, there is no problem even if the amount of lubricating oil is small.

In this way, by controlling the amount of oil supplied to the low-speed lubricating oil passage 24 and the high-speed lubricating oil passage 25 according to the operating state of the engine using the control valve 56, the minimum necessary lubricating oil is supplied to the hydraulic supply source 54. The oil pressure can be supplied from the hydraulic pressure supply source 54, thereby making it possible to downsize the hydraulic pressure supply source 54 and save energy accordingly.

As another embodiment of the present invention, at least one of the low-speed cams 3, 3 is formed as a perfectly circular raised portion concentric with the camshaft 2, and the intake valve 1a is used during low-speed operation of the engine.

At least one of the valves 1b may be closed.

In the above embodiments, a valve operating device for an intake valve has been described, but it is also possible to implement the present invention in connection with an exhaust valve.

C8 Effects of the Invention As described above, according to the present invention, there is provided a low-speed lubricating oil passage for supplying lubricating oil to the sliding contact portion between the low-speed cam or the raised portion and the cam follower, and a high-speed cam and the cam follower. A high-speed lubricating oil passage for supplying lubricating oil toward the sliding portion is provided independently from each other, and between the low-speed lubricating oil passage and the high-speed lubricating oil passage and the hydraulic pressure supply source, When the engine is operating at low speeds, the amount of circulating oil is reduced to provide communication between the high-speed lubricating oil path and the hydraulic pressure supply source over the entire operating range of the engine, and the communication between the low-speed lubricating oil path and the hydraulic power supply source is maintained at least during low-speed engine operation. Since a control valve configured to communicate with the engine is installed, the necessary amount of lubricant is supplied to the low-speed lubricating oil passage and the high-speed lubricating oil passage depending on the operating state of the engine, and the overall lubricating oil supply amount is This makes it possible to downsize the hydraulic supply source and save energy. Moreover, since the high-speed cam and the cam follower are in sliding contact over the entire operating range of the engine, lubricating oil can be constantly supplied to the sliding contact portion, contributing to reducing the valve operating load.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional side view taken along the line II in FIG. 3 is a simplified plan view of FIGS. 1 and 2, FIG. 4 is an enlarged sectional view taken along line IV-IV of FIG. 2 when the connection switching mechanism is disconnected, and FIG. The figure is a sectional view corresponding to FIG. 4 when the connection switching mechanism is connected. la, lb...Intake valve, 2...Camshaft, 3...
...Low speed cam, 5...High speed cam, 7,8.9...
・Rocker arm as a cam follower, IO...Connection switching mechanism, 25...Low speed lubricating oil path, 26...High speed lubricating oil path, 56...Control valve

Claims (3)

[Claims] (1) A low-speed cam or a perfectly circular protuberance that corresponds to the operation mode of the intake valve or exhaust valve during low-speed operation of the engine;
A high-speed cam corresponding to the operation mode of the intake valve or exhaust valve during high-speed operation of the engine is provided on the camshaft, and is biased by a low-speed cam or a cam follower that slides on the protrusion, and a resilient biasing means. In a valve train for an internal combustion engine, a connection switching mechanism is provided between a cam follower that slides on a high-speed cam and switches the connection and disconnection of the cam follower to open and close an intake valve or an exhaust valve depending on the operating state of the engine. , a low-speed lubricating oil passage for supplying lubricating oil toward the sliding contact between the low-speed cam or the protrusion and the cam follower, and a low-speed lubricating oil passage for supplying lubricating oil toward the sliding contact between the high-speed cam and the cam follower. High-speed lubricating oil passages are provided independently from each other, and a system is installed between the low-speed lubricating oil passage and the high-speed lubricating oil passage and the hydraulic pressure supply source so as to reduce the amount of oil flowing during low-speed operation of the engine. A control valve is interposed to communicate between the high-speed lubricating oil passage and the hydraulic pressure supply source over the entire operating range of the engine, and to communicate between the low-speed lubricating oil passage and the hydraulic pressure supply source at least during low-speed operation of the engine. A valve train for an internal combustion engine characterized by: (2) The control valve is configured to allow communication between the hydraulic pressure supply source and the low-speed lubricating oil path during high-speed operation of the engine by limiting the amount of circulating oil to a small amount. A valve train for an internal combustion engine according to item (1). (3) The connection switching mechanism is configured to be switched by the action of hydraulic pressure, and the high-speed lubricating oil passage is connected to the connection switching mechanism. (2) A valve train for an internal combustion engine as described in item (2).