JPH0313402B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field The present invention provides a cam or a perfectly circular protrusion that corresponds to the operation mode of an intake valve or an exhaust valve during low-speed operation of an engine; A cam corresponding to the operation mode of the intake valve or exhaust valve during high-speed operation of the engine is installed on the camshaft, and between a plurality of cam followers that individually slide on the cams or protuberances, the intake valve is adjusted according to the operating state of the engine. The present invention relates to a valve operating system for an internal combustion engine that is provided with a connection switching mechanism that switches connection and disconnection of a cam follower to open and close a valve or an exhaust valve.

(2) Conventional technology Conventionally, such a valve train has been developed, for example, by
It is publicly known from Publication No. 19911 and the like.

(3) Problems to be solved by the invention By the way, in such a valve train, in order to lubricate the sliding contact between the cam or the protrusion and the cam follower,
Lubricating oil is supplied to the sliding contact portions, and in conventional systems, lubricating oil is supplied equally to each sliding contact portion. However, the sliding contact area between the cam or the protrusion and the cam follower, which is compatible with low-speed engine operation, has a relatively small sliding load when the engine is running at high speed, and the sliding contact area between the cam and cam follower, which is compatible with high-speed engine operation, is relatively small. The sliding load is relatively small when the engine is operating at low speed. Therefore, if the amount of lubricating oil supplied to each sliding contact part is controlled according to the operating state of the engine, it is possible to achieve sufficient lubrication with a relatively small amount of lubricating oil, and the hydraulic pressure supply of oil pumps, etc. It would also be possible to downsize the source.

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.

B. Structure of the Invention (1) Means for Solving the Problems According to the present invention, a low speed control system for supplying lubricating oil toward the sliding contact portion between the cam or the protrusion and the cam follower corresponding to low speed operation of the engine is provided. A high-speed lubricating oil passage for supplying lubricating oil to the sliding contact parts of the cam and cam follower corresponding to high-speed operation of the engine are provided independently from each other,
A low-speed lubricating oil passage and a hydraulic oil supply source are provided between the low-speed lubricating oil passage and the hydraulic pressure supply source, and are configured to control the flow rate between both the lubricating oil passages and the hydraulic pressure supply source in accordance with changes in the operating state of the engine. A control valve is interposed.

(2) Effect According to the above configuration, when the engine is operating at low speed, the lubricating oil path for low speed is lubricated as the sliding load on the sliding contact area between the cam or protrusion corresponding to low speed operation and the cam follower increases. When the engine is operating at high speed, lubricating oil can be supplied to the high-speed lubricating oil path in response to the increased sliding load on the sliding contact area between the cam and cam follower, which supports high-speed operation.
The total supply amount of lubricating oil can be controlled to the necessary minimum.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIGS. 1, 2, and 3, a pair of intake valves 1 provided in the engine body E are shown.
a and 1b are low-speed cams 3, 3 and high-speed cam 5, which are provided integrally with a camshaft 2 that is rotationally driven from the engine crankshaft at a reduction ratio of 1/2, and a rock shaft 6 that is parallel to the camshaft 2. 1st, 2nd and 3rd as pivoted cam followers
Rotsuka arms 7, 8, 9 and each Rotsuka arm 7~
The opening/closing operation is performed by the action of the connection switching mechanism 10 provided between the openings and the openings.

The camshaft 2 is rotatably arranged above the engine body E, both low-speed cams 3, 3 are integrated into the camshaft 2 in correspondence with the respective intake valves 1a, 1b, and the high-speed cam 5 is connected to both low-speed cams. It is integrated into the camshaft 2 between the cams 3 and 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 circular portion 3a and a high portion 3b protruding radially outward from the base circular portion 3a. The high-speed cam 5 has a shape suitable for high-speed operation of the engine, and has a base circular portion 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 includes a first rocker arm 7 having a cam slipper 11 on its upper part that slides against one of the low-speed cams 3, a second rocker arm 8 that has a cam slipper 12 on its upper part that slides against the other low-speed cam 3, and a high-speed rocker arm 8. cam 5
A third cam slipper 13 having a cam slipper 13 in sliding contact with the third
A rocker arm 9 is adjacent to and pivotally supported in the axial direction of the rocker shaft 6, respectively.

Intake valves 1a and 1b are interlocked and connected to the first and second rocker arms 7 and 8. That is, each intake valve 1a, 1b has a flange 14 provided at its upper end,
15 and the valve spring 1 interposed between the engine body E
6 and 17 in the valve closing direction, that is, upwardly, and the first and second rocker arms 7,
Tappet screws 18 and 19 that abut the upper ends of the intake valves 1a, 1b are screwed into the tips of the valves 8 so as to be movable forward and backward.

The third rocker arm 9 is biased by resilient biasing means 20 provided between the third rocker arm 9 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 lifter 21 whose closed end is in contact with the lower surface of the third rocker arm 9.
and a lifter spring 22 interposed between the lifter 21 and the engine body E, and the lifter 21 is slidably fitted into a bottomed hole 23 provided in the engine body E.

Above the camshaft 2 is a cam holder (not shown) that rotatably supports the camshaft 2.
A passage forming body 24 is constructed across the space,
This passage forming body 24 includes a low-speed lubricating oil passage 25.
and a high-speed lubricating oil passage 26 are drilled independently and parallel to each other. In addition, an ejection hole 27 communicating with the low-speed lubricating oil passage 25 is bored in the lower part of the passage forming body 24 at a position corresponding to the sliding contact portion of the low-speed cams 3, 3 and the cam slippers 11, 12. In addition, 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 to form a passage. connected to the body 24;

Referring also to FIG. 4, the connection switching mechanism 10
A first switching pin 33 that can connect between the first and third rocker arms 7 and 9, and a second switching pin 34 that can connect between the third and second rocker arms 9 and 8.
, a third switching pin 35 that restricts movement of the first and second switching pins 33 and 34, and each connecting pin 33 to
and a return spring 36 that urges 35 toward the disconnection side.

A first guide hole 37 parallel to the rocker shaft 6 is bored in the first rocker arm 7, and the end of the first guide hole 37 opposite to the third rocker arm 9 is closed with a closing member 38. . The first switching pin 33 is slidably engaged with the first guide hole 37 , and a hydraulic chamber 39 is defined between the closing member 38 and the first switching pin 33 within the first guide hole 37 .
Further, an oil passage 40 communicating with the hydraulic chamber 39 is bored in the first rocker arm 7, and a hydraulic pressure supply passage 41 is provided in the rocker shaft 6. The oil passage 40 and the oil pressure supply passage 41 are connected to the first rocker arm 7 through a communication hole 42 bored in the side wall of the rocker shaft 6.
Always communicates regardless of the swing state. The communication hole 42 also functions to supply lubricating oil from the hydraulic pressure supply path 41 between the rocker shaft 6 and the first rocker arm 7.

In the third rocker arm 9, a second guide hole 43 having the same diameter as the first guide hole 37 is bored between both sides of the third rocker arm 9 in parallel with the rocker shaft 6. A second switching pin 34 having a length spanning the entire length of the second switching pin 34 is slidably engaged.

A third guide hole 44 having the same diameter and the same diameter as the second guide hole 43 is bored in the second rocker arm 8 in parallel with the rocker shaft 6, and the third guide hole 44 is opposite to the third rocker arm 9. The side end is closed with a closing member 45. Third guide hole 44
A third switching pin 35 is slidably connected to the third switching pin 35, and a small-diameter shaft portion 4 coaxially connected to the third switching pin 35 is slidably connected to the third switching pin 35.
6 is movably inserted into a guide hole 47 formed in the closing member 45. Moreover, a return spring 36 is interposed between the closing member 45 and the third switching pin 35 so as to surround the shaft portion 46 . 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.

On the side wall of the rock shaft 6, a third and a second
Communication hole 4 in the part corresponding to rocker arms 9 and 8
8 and 49 are drilled, and these communication holes 4
Reference numerals 8 and 49 supply lubricating oil from the hydraulic pressure supply path 41 to the rocker shaft 6 and the third and second rocker arms 9,8.
Supply between.

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 surface is located at a position corresponding to between the first and third rocker arms 7 and 9, and the contact surface is located between the second and third switching pins 34 and 35.
The abutment surface of is located at a position corresponding to between the third and second rocker arms 9 and 8, and the rocker arms 7 to 9 are not connected. Further, when high hydraulic pressure is supplied to the hydraulic chamber 39, each switching pin 33 to 35 is moved by the return spring 36.
The first switching pin 33 slides into the second guide hole 43, the second switching pin 34 slides into the third guide hole 44, and each rocker arm moves in the direction away from the hydraulic chamber 39 against the spring force. 7 to 9 are connected.

The hydraulic pressure supply path 41 and the high-speed lubricating oil path 26 are
They are communicated via an oil passage 50 having a throttle 51 in the intermediate portion, and the hydraulic pressure supplied to the oil pressure supply passage 41 is throttled by the throttle 51 and supplied to the high-speed lubricating oil passage 26 .

An oil passage 52 connected to the oil pressure supply passage 41 , an oil passage 53 connected to the low-speed lubricating oil passage 25 , and the oil pressure supply source 5
A control valve 56 that operates in response to changes in the operating state of the engine is interposed between the oil passage 55 and the oil passage 55 connected to the engine 4.

This control valve 56 has a cylinder body 60 having three annular recesses 57, 58, 59 spaced apart in the axial direction on the inner surface, and three annular grooves 61, 62, 63 spaced apart in the axial direction on the outer surface. Plunger 6 with
4 are rubbed together. The cylinder body 60 is provided with an input port 65 connected to the oil pressure supply source 54 via an oil path 55 corresponding to the annular recess 58, an output port 66 connected to the oil path 52, and an output port 66 connected to the oil path 53. The port 67 is connected to the annular recess 57,5
It is drilled corresponding to 9.

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. Annular grooves 61, 6 of this plunger 64
The land 68 between the two is formed so that it slides on 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. 62,
The land 69 between the cylinders 63 and 63 is formed so as to be in sliding contact with the inner surface of the cylinder body 60 between the annular recesses 58 and 59 regardless of the operating state of the engine. Moreover, land 68
A throttle hole 70 connecting the annular grooves 61 and 62 is bored in the land 69, and a throttle hole 71 is bored in the land 69 with one end opening into the annular groove 62 and the other end opening into the outer surface of the land 69. The other end of the throttle hole 71 communicates with the annular recess 59 when the engine is operating at low speed, and is opened to the outer surface of the land 68 so as to be closed by the inner surface of the cylinder body 60 when the engine is operating at high speed.

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 65 and the output port 66 communicate with each other through 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. The hydraulic pressure throttled by the throttle hole 70 is ejected little by little from the lubricating oil spouting pipe 28, thereby increasing the hydraulic pressure supply path 41, that is, the hydraulic pressure chamber 3.
9 becomes a relatively low pressure, and the connection switching mechanism 10
In this case, each of the switching pins 33 to 35 is at a position where it has been moved to the maximum extent toward the hydraulic chamber 39 by the spring force of the return spring 36. In this state, the first and second switching pins 3
The contact surfaces of 3 and 34 are located at positions corresponding to between the first and third rocker arms 7 and 9, and
The contact surfaces of the switching pins 34 and 35 are located at positions corresponding to between the third and second rocker arms 9 and 8. Therefore, each of the rocker arms 7 to 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 second rocker arms 7, 8 to
swings in response to sliding contact with the low-speed cams 3, 3, and both intake valves 1a, 1b are opened and closed at timing and lift amount depending on the shape of the low-speed cams 3, 3.
At this time, the third rocker arm 9 swings in response to sliding contact with the high-speed cam 5, but the swinging action has no effect on the first and second rocker arms 7, 8.

In addition, in this disconnected state, the control valve 56
The input port 65 and the output port 67 communicate with each other through a throttle hole 71, and the hydraulic pressure from the hydraulic pressure supply source 54 is throttled through the throttle hole 71 and supplied to the low-speed lubricating oil passage 25, thereby reducing the sliding load. Low-speed cams 3, 3 and cam slipper 11, which are relatively large.
A relatively small amount of lubricating oil is ejected from the ejection hole 27 onto the sliding contact portion 12 . At this time, as described above, a small amount of lubricating oil is also jetted 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 urged upward by the elastic urging means 20. The sliding contact portion between the cam slipper 13 of the third rocker 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. As a result, the annular recesses 57 and 58 communicate with each other via the annular groove 62, and the throttle hole 71 is blocked. 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.
Therefore, in the connection switching mechanism 10, each switching pin 33
35 moves toward the connection position against the spring force of the return spring 36, the first switching pin 33 slides into the second guide hole 43, and the second switching pin 34 slides into the third guide hole 44. The rocker arms 7 to 9 are connected to each other. At this time, since the amount of rocking of the third rocker arm 9 in sliding contact with the high-speed cam 5 is the largest, the first and second rocker arms 7 and 8
Both intake valves 1a and 1b are opened and closed at timing and lift amount according to the shape of the high-speed cam 5.

During the connection operation of such a connection switching mechanism 10,
The area where the sliding load is large is the sliding contact between the high-speed cam 5 and the cam slipper 13, where oil, which has been squeezed by the throttle 51 and has a relatively low pressure, flows from the lubricating oil spouting pipe 28. It is squirted. On the other hand, since the sliding load on the sliding contact portions of the low-speed cams 3, 3 and the cam slippers 11, 12 is small, the low-speed lubricating oil path 25
There is no problem even if the oil supply is cut off.

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.

In another embodiment of the present invention, at least one of the low-speed cams 3, 3 is formed into a perfectly circular raised portion concentric with the camshaft 2, so that the intake valve 1
At least one of a and 1b may be closed and paused.

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.

C. Effects of the Invention As described above, according to the present invention, there is provided a low-speed lubricating oil path for supplying lubricating oil toward the sliding contact portion between the cam or the protrusion and the cam follower corresponding to low-speed operation of the engine, and the engine. A high-speed lubricating oil passage for supplying lubricating oil to the sliding contact parts of the cam and cam follower corresponding to high-speed operation is provided independently from each other, and a low-speed lubricating oil passage and a high-speed lubricating oil passage are provided. A control valve configured to control the flow rate between both lubricating oil passages and the hydraulic pressure supply source in accordance with changes in the operating state of the engine is interposed between the oil pressure supply source and the oil pressure supply source. It is possible to supply the required amount of lubricating oil to the low-speed lubricating oil path and the high-speed lubricating oil path depending on the situation, reducing the overall amount of lubricating oil supplied, and making the hydraulic supply source more compact and energy-saving. can.

[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 -- in FIG. 3, and FIG. 2 is a longitudinal sectional side view taken along the line -
3 is a simplified plan view of FIGS. 1 and 2, FIG. 4 is an enlarged sectional view taken along the - line in FIG. 2 when the connection switching mechanism is disconnected, and FIG. FIG. 5 is a sectional view corresponding to FIG. 4 when the mechanism is connected; 1a, 1b...Intake valve, 2...Camshaft,
3, 5...Cam, 7, 8, 9...Rocker arm as cam follower, 10...Connection switching mechanism, 2
5...Low speed lubricating oil passage, 26...High speed lubricating oil passage, 56...Control valve.

Claims (1)

[Scope of Claims] 1. A cam or a perfectly circular protrusion that corresponds to the operation mode of the intake valve or exhaust valve when the engine is running at low speed, and a cam or a perfectly circular protrusion that corresponds to the operation mode of the intake valve or exhaust valve when the engine is running at high speed. A cam is provided on the camshaft, and between a plurality of cam followers that individually slide into contact with these cams or protrusions, the cam followers are connected and disconnected in order to open and close the intake valve or exhaust valve depending on the operating state of the engine. A low-speed lubricating oil passage for supplying lubricating oil toward a sliding contact portion between a cam or a raised portion and a cam follower corresponding to low-speed operation of the engine in a valve train for an internal combustion engine that is provided with a coupling switching mechanism for switching; A high-speed lubricating oil path is provided independently from each other to supply lubricating oil to the sliding contact parts of the cam and cam follower during high-speed operation of the engine, and a low-speed lubricating oil path and a high-speed lubricating oil path are provided. and the hydraulic supply source.
A valve train for an internal combustion engine, characterized in that a control valve configured to control the flow rate between both lubricating oil passages and a hydraulic pressure supply source according to changes in the operating state of the engine is installed. 2. The valve train for an internal combustion engine according to claim 1, wherein the connection switching mechanism is configured to perform a switching operation by the action of hydraulic pressure, and the high-speed lubricating oil passage is connected to the connection switching mechanism. Device.