JPS63170513A - Valve system for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the biased abrasion by forming a connecting arm section on a driven rocker arm and providing a connection switching mechanism between the connecting arm section and a free rocker arm. CONSTITUTION:A connecting arm section 12 bent to a free rocker arm 8 side and extended in parallel with a rocker shaft 6 is integrally formed on a driven rocker arm 7, A connection switching mechanism 9 having a connecting pin 22 movable in the vertical direction to the axis of the rocker shaft 6 is provided between the connecting arm section 12 and the free rocker arm 8. Accordingly, no angular moment is applied to the rocker arms when they are connected, thus the biased abrasion of a cam can be prevented.

Description

Detailed Description of the Invention A0 Objective of the Invention (1) Industrial Field of Application The present invention relates to a drive rocker arm that is interlocked and connected to an intake valve or an exhaust valve, and a drive rocker arm that can be freed from the intake valve or the exhaust valve. The rocker arms are arranged adjacent to each other so as to be able to operate in different manners depending on the rotation of the camshaft, and a connection switching mechanism is provided between each rocker arm that can switch between connection and disconnection. Regarding a valve device.

(2) Conventional technology Conventionally, such a valve train has been developed, for example, by
It is known from the publication No. 317.

(3) Problems to be Solved by the Invention However, in the conventional technique described above, the connection switching mechanism is configured to move the connection pin in a direction parallel to the axis of the rocker shaft. Therefore, when the rocker arms that operate in different manners are connected with the connecting pin when the connection is released, the other rocker arm will move in response to the movement of one adjacent rocker arm along the axis of the rocker shaft. A rotational moment about an axis perpendicular to the rocker shaft in a plane including the axes of the rocker shaft and the connecting pin acts on the rocker arm, and the cam slipper provided on the rocker arm comes into partial contact with the cam, causing uneven wear.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a valve operating system for an internal combustion engine that avoids the application of rotational moment to the rocker arm during connection by the connection switching mechanism.

B0 Structure of the Invention (11 Means for Solving the Problems) According to the present invention, one of the driving rocker arm and the free rocker arm is provided with a connecting arm portion extending to the other side, and the connecting arm portion is connected to the other rocker arm. A connection switching mechanism having a connection pin movable in a direction substantially perpendicular to the axis of the rocker shaft is provided in between.

(2) Effect According to the above configuration, the connecting pin moves in a direction substantially perpendicular to the axis of the rocker shaft to switch between connecting and disconnecting, so no rotational moment is applied to each rocker arm when connecting, and the cam Also, uneven wear of the cam slipper is also prevented.

(3) Examples Examples of the present invention will be explained below with reference to drawings.
First, in FIGS. 1 and 2 showing a first embodiment of the present invention, an intake valve 1 provided in an engine body E is connected to a camshaft 2 driven by a camshaft 2 driven at a reduction ratio of 1/2 from the engine crankshaft.
A low speed cam 3 and a high speed cam 5 provided in It is driven to open and close by working with the connection switching mechanism 9.

The camshaft 2 is rotatably arranged above the engine body E, and the low-speed cam 3 is integrated into the camshaft 2 in correspondence with the drive rocker arm 7, and the high-speed cam 5 corresponds to the free rocker arm 8. and is integrated into the camshaft 2. The low-speed cam 3 has a shape suitable for low-speed operation of the engine, and includes 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 a base interior 5a and the high portion 3b.
It has a higher portion 5b which has a larger protrusion amount and center angle range than the other.

The rocker shaft 6 is fixedly arranged below the camshaft 2. This rocker shaft 6 has a low speed cam 3.
a drive rocker arm 7 having a cam slipper 10 on its upper part that slides on the cam slipper 11 that slides on the high-speed cam 5;
Free rocker arms 8 having upper portions thereof are each pivoted axially adjacent to the rocker shaft 6 .

The drive rocker arm 7 is integrally provided with a connecting arm 12 that is bent toward the free rocker arm 8 and extends parallel to the rocker shaft 6, and the intake valve 1 is interlocked and connected to the tip of the connecting arm 12. . That is, the intake valve 1 is biased upward by a valve spring 14 interposed between a flange 13 provided at the upper part of the intake valve 1 and the engine body E, and a tappet screw that can come into contact with the upper end of the intake valve 1 is pressed upward. 15 is screwed onto the tip of the connecting arm 12 so that it can move forward and backward.

The free rocker arm 8 is biased by resilient biasing means 16 provided between the free rocker arm 8 and the engine body E in a direction in which its cam slipper 11 is constantly in sliding contact with the high-speed cam 5.

This spring biasing means 16 allows the closed end to be moved to the free rocker arm 8.
A bottomed cylindrical glue lid 17 that is brought into contact with the lower surface of the engine, and a lifter spring 1B that is interposed between the lifter 17 and the engine body 8.
The lifter 17 is slidably fitted into a bottomed hole 19 provided in the engine body E.

The distal end surface of the free rocker arm 8 and the connecting arm portion 12 of the drive rocker arm 7 are in sliding contact so that the double-ended hook arm 7.8 can relative swing about the axis of the rocker shaft 6. namely the free rocker arm 8 and the driving rocker arm 7.
A sliding contact surface 20.21 with the connecting arm portion 12 is formed in an arc shape centered on the axis of the rocker shaft 6.

The connection switching mechanism 9 includes a connection pin 22 that can connect the free rocker arm 8 and the drive rocker arm 7, and a connection pin 22.
2, and a return spring 24 that urges the connecting pin 22 and the stopper 23 toward the disconnection side.

A first guide hole 25 extending in a direction substantially perpendicular to the axis of the rocker shaft 6 is bored in the sliding surface 20 of the free rocker arm 8, with a step 26 facing the open end thereof. A connecting pin 22 is slid into the first guide hole 25 , and a hydraulic chamber 27 is defined between the closed end of the first guide hole 25 and the connecting pin 22 . Further, an oil passage 28 communicating with the hydraulic chamber 27 is bored in the free rocker arm 8, and an oil passage 29 communicating with a hydraulic pressure supply source (not shown) is provided in the rocker shaft 6.
The two oil passages 28 and 29 provided with the rocker shaft 6
The free rocker arm 8 is always in communication with the free rocker arm 8 through a communication hole 30 formed in the side wall thereof, regardless of the swinging state of the free rocker arm 8.

A first guide hole 2 is provided in the sliding surface 21 of the drive rocker arm 7.
5, a second guide hole 31 extending in a direction perpendicular to the axis of the rocker shaft 6 is bored with the same diameter as the first guide hole 25. A disc-shaped stopper 23 is slid into the second guide hole 31 . A small-diameter shaft portion 32 is coaxially connected to the 7 bar 23, and the shaft portion 32 is movably inserted into a guide hole 33 provided in the drive rocker arm 7 at the closed end of the second guide hole 31. Ru.

A stopper 23 and a second guide hole 31 surround the shaft portion 32.
A return spring 24 is interposed between the closed end and the stopper 23, and the spring force of the return spring 24 causes the stopper 23 to come into contact with the connecting pin 22, and the stopper 23 and the connecting pin 22 are urged toward the disconnection side.

Moreover, the axial length of the connecting pin 22 is such that when the connecting pin 22 and the stopper 23 are in contact with the stepped portion 26, the contact surfaces of the connecting pin 22 and the stopper 23 are
It is set at a position corresponding to the sliding contact surface 20.21.

Next, the operation of the first embodiment will be explained. When the engine is operated at low speed, hydraulic pressure is not supplied to the hydraulic chamber 27. Therefore, in the coupling switching mechanism 9, the coupling pin 22 and the stopper 23 are moved toward the hydraulic chamber 27 by the return spring 24. moving as much as possible. In this state, the contact surfaces of the connecting pin 22 and the stopper 23 are in positions corresponding to the sliding contact surfaces 20.21, and the free rocker arm 8 and the drive rocker arm 7 are capable of relative angular displacement.

In such a disconnected state of the connection switching mechanism 9,
Due to the rotation of the camshaft 2, the free loca arm 8 swings in accordance with the sliding contact with the high speed cam 5, and the drive loca arm 7
swings in response to sliding contact with the low speed cam 3. Therefore, the intake valve 1 opens and closes at a timing and lift amount depending on the shape of the low-speed cam 3.

When the engine is operating at high speed, hydraulic pressure is supplied to the hydraulic chamber 27. As a result, the connecting pin 22 slides into the second guide hole 31 while pressing the stopper 23 against the spring force of the return spring 24 . This movement occurs through the first and second guide holes 25.
31 are aligned, and the drive rocker arm 7 and the free rocker arm 8 are connected via the connection pin 22.

Therefore, the free rocker arm 8 in sliding contact with the high-speed cam 5
The drive rocker arm 7 operates in response to the operation of the intake valve l.
The opening/closing operation is performed at a timing and lift amount depending on the shape of the high-speed cam 5.

By the way, when the driving rocker arm 7 and the free rocker arm 8 are connected in this way, the connecting pin 22 connecting them is perpendicular to the axis of the rocker shaft 6, so the connecting pin 22 is connected to the double-ended lock arm 7°8. (Therefore, uneven contact between the low-speed cam 3 and the cam slipper 10 and the high-speed cam 5 and the cam slipper 11 is prevented, and the cam 3.5 and the cam slipper 10.11 The occurrence of uneven wear can be prevented.

FIG. 3 shows a second embodiment of the present invention, and parts corresponding to those in the first embodiment are given the same reference numerals.

The drive rocker arm 7 has a connecting arm 12 formed in an oval shape on the opposite side of the rocker shaft 6 from the connecting arm 12 of the first embodiment and extending toward the free rocker arm 8.
a is integrally provided, and the free rocker arm 8 is provided with a projecting portion 34 that slides into sliding contact with the connecting arm portion 12a. Furthermore, a connection switching mechanism 9 having a connection pin 22 that moves in a direction orthogonal to the axis of the rocker shaft 6 is provided between the connection arm 12a and the protrusion 34.

This second embodiment can also provide the same effects as the first embodiment.

FIG. 4 shows a third embodiment of the present invention, in which the free rocker arm 8 has a connecting arm 12a of the drive rocker arm 7.
An abbreviated connecting arm portion 12b that slides into contact with is integrally provided, and a connection switching mechanism 9 is provided between the reconnecting arm portions 12a and 12b.

This third embodiment can also provide the same effects as the first and second embodiments.

FIG. 5 shows a fourth embodiment of the present invention, which shows a first free rocker arm 8 having cam slippers 1, 1 that are in sliding contact with a high-speed cam (not shown), and a cam slipper that is in sliding contact with a medium-speed cam (not shown). A second free rocker arm 36 having 35 is pivotally mounted on the rocker shaft 6 adjacent to each other. Also, a pair of drive rocker arms 7.7 are interlocked and connected to the pair of intake valves 1, 1, respectively, and have cam slippers 10.10 that slide into low-speed cams (not shown). It is pivotally supported on rocker shafts 6 on both sides. Moreover, the drive rocker arm 7
．． 7 connecting arms 12.12 and both free rocker arms 8.
A connection switching mechanism 9 having a connection pin 22 that moves in a direction perpendicular to the axis of the rocker shaft 6 is individually provided between the rocker shaft 36 and the rocker shaft 6 .

According to this fourth embodiment, when the engine is operating at low speed, both coupling switching mechanisms 9.9 are in a disconnected state, and both intake valves 1.1
opens and closes with timing and lift amount depending on the shape of the low-speed cam. Also, when the engine is operating at medium speed, one of the coupling switching mechanisms 9 is used to connect one of the drive rocker arms 7 and the second drive rocker arm.
The free rocker arm 36 is connected, and the other driving rocker arm 7 and the first free rocker arm 8 are in a disconnected state. In such a state, one intake valve 1 opens and closes with timing and lift amount depending on the shape of the medium-speed cam, while the other intake valve 1 opens and closes with timing and lift amount depending on the shape of the low-speed cam. Opens and closes. Furthermore, during high-speed operation of the engine, the second free rocker arm 36 and one drive rocker arm 7 remain connected, and the first free rocker arm 8 and the other drive rocker arm 7 are connected by the connection switching mechanism 9. Therefore, one intake valve 1
The intake valve 1 opens and closes with timing and lift amount depending on the shape of the medium-speed cam, and the other intake valve 1 opens and closes with timing and lift amount depending on the shape of the high-speed cam. Moreover, when each connection switching mechanism 9.9 is connected, each rocker arm 7
．． Similar to the above embodiments, no rotational moment acts on 7.8.36.

As a fifth embodiment, which is a modification of the fourth embodiment, the redrive rocker arm 7.7 is connected to the first and second rocker arms as shown in FIG.
It may also be pivoted to the rocker shaft 6 between free rocker arms 8.36.

FIG. 7 shows a sixth embodiment of the present invention, and parts corresponding to each of the above embodiments are given the same reference numerals.

On both sides of the free rocker arm 8', which has cam slippers 11' that slide on a high-speed cam (not shown), the rocker shaft 6 has cam slippers that are interlocked and connected to the intake valve 1.1 and that slide on a low-speed cam (not shown). A drive rocker arm 7.7 having a diameter of 10.10 is pivoted. Moreover, between the free rocker arm 8' and the connecting arm part 12.12 of the re-driving rocker arm 7.7, a connecting switching mechanism 9. 9 is provided.

In this sixth embodiment, one coupling switching mechanism 9 is operated to couple the free rocker arm 8' and one driving rocker arm 7.
When the two intake valves 1 and 1 are connected, one of the intake valves 1 opens and closes at a timing and lift amount according to the shape of the high-speed cam, and when the reconnection switching mechanism 9.9 is connected and operated, both intake valves 1.
1 opens and closes with timing and lift amount depending on the shape of the high-speed cam.

In each of the embodiments shown in FIGS. 5, 6, and 7, only one of the redrive rocker arms 7.7 is brought into sliding contact with the low-speed cam, and the other is not brought into sliding contact with the cam to connect the connection switching mechanism. The valve may be stopped when the valve is released.

In each of 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.

C0 Effects of the Invention As described above, according to the present invention, one of the driving rocker arm and the free rocker arm is provided with a connecting arm extending to the other side, and between the other rocker arm and the connecting arm,
Since a connection switching mechanism having a connection pin movable in a direction substantially perpendicular to the axis of the rocker shaft is provided, rotational moment is prevented from acting on the rocker arm when the connection pin is connected, and uneven contact between the cam and the cam slipper is prevented. By preventing this from occurring, uneven wear of the cam and cam slipper can be prevented.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view, FIG. 2 is a view taken along line nn of FIG. 1, and FIGS. 5, 6 and 7 are second, third, fourth, fifth and sixth embodiments of the present invention.
It is a top view corresponding to the figure.

Claims (1)

[Claims] A driving rocker arm that is interlocked and connected to the intake valve or the exhaust valve and a free rocker arm that can be free with respect to the intake valve or the exhaust valve are arranged adjacently so that they can operate in different manners depending on the rotation of the camshaft. In a valve train for an internal combustion engine, in which a connection switching mechanism is provided between each rocker arm and can switch between mutual connection and disconnection, one of the drive rocker arm and the free rocker arm is provided with a connection arm portion extending to the other side. A valve train for an internal combustion engine, characterized in that a connection switching mechanism having a connection pin movable in a direction substantially orthogonal to the axis of the rocker shaft is provided between the other rocker arm and the connection arm.