JPH0255602B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve operating device that selectively turns on and off the interlocking state between a cam and a valve of an engine depending on the operating state.

(Prior Art) A mechanism for selectively stopping the interlocking state between a cam and a valve of a specific valve operating mechanism of an engine according to the operating state, for example, a valve operating stop mechanism is known. For example, in Utility Model 57-182205, 1
A valve driving device is disclosed that includes a rocker arm having high-speed and low-speed cams formed on a camshaft and an abutting member that abuts each of the cams for each valve. In this disclosed device, the high-speed cam abutting member that abuts the high-speed cam is configured to be slidable, and the stopper that prevents this sliding is configured to be actuated by an actuator driven by engine oil depending on the operating state. The high-speed cam abutting member or the low-speed cam abutting member of the rocker arm is operated selectively.

(Problems to be Solved) However, in the device disclosed in Utility Model Application No. 57-182205, a hydraulic actuator for controlling a stopper for selectively operating the high-speed cam contact member is assembled in the rocker arm. Because it is crowded,
As the structure of the Rocker arm becomes more complex, the inertial weight increases, causing problems such as valve jumps at high engine speeds, as well as unfavorable results in terms of vibration and durability.

(Means for solving the above problems) The present invention is configured as follows in order to solve the above problems.

The valve operating device of the present invention includes a rocker arm having a first arm and a second arm, both of which are swingably supported by a rocker shaft. One end of the first arm of the rocker arm abuts the stem ends of the intake and exhaust valves, and the second arm abuts the cam surface of the camshaft at one end. The rocker arm has two states: a locked state in which the first arm and the second arm swing around the rocker shaft in an integrated state, and a locked state in which the second arm swings around the rocker shaft independently from the first arm. It is configured to be able to selectively take the unlocked state. Furthermore, the valve actuation device of the present invention includes:
The selector member includes a lock member that moves in the axial direction of the rocker shaft to switch between the locked state and the unlocked state, and a drive mechanism that controls the movement of the selector member depending on the operating state of the engine. The selector member is mounted on the rocker shaft so as to be movable at least in the axial direction of the rocker shaft in close proximity to a side portion of the rocker arm consisting of the first arm and the second arm.

(Operation) According to the present invention, when the locking member of the selector member is activated by the drive mechanism, the first arm and the second arm of the rocker arm are in a locked state, and the first arm and the second arm are integrated. hand,
It swings around the rocker shaft. Therefore,
In this state, the valve operating force transmitted to the rocker arm via the cam surface is transmitted to the valve stem through the second arm and the first arm, and the intake and exhaust valves are opened and closed at predetermined timing. Meanwhile, the selector member moves in the axial direction of the rocker shaft,
When the locking state by the locking member is released, the operating force from the cam surface is transmitted only to the first arm and not to the second arm. That is, in this state, the second arm swings around the rocker arm independently of the first arm while contacting the cam surface, and the first arm is maintained in a stopped state.
The intake and exhaust valves are maintained closed.

For example, such a mechanism can be applied to an engine that obtains a desired output through so-called reduced-cylinder operation, in which some cylinders are stopped during low-load operation of the engine, and only specific cylinders are operated. By configuring the system to stop the valve train of the stopped cylinder, pumping loss can be reduced and fuel efficiency can be improved.

Furthermore, the present invention can be applied to an engine having a plurality of intake valves in one cylinder, and the operation of some specific valves can be stopped to obtain a desired intake flow rate.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, each cylinder C of the engine of this example has two intake ports and one exhaust port, and two intake valves are used to open and close the intake ports. Two intake valve rocker arms 10, 12 are associated with each intake valve. Further, an exhaust valve rocker arm 14 is provided to open and close the exhaust valve. The rocker arms 10 and 12 for intake valves and the rocker arm 14 for exhaust valves are swingably supported by rocker shafts 16 and 18 extending in the column direction of the cylinders C. One intake valve rocker arm 12 and one exhaust valve rocker arm 16 have the structure and function of a normal rocker arm. To explain the other intake valve rocker arm 10 in detail, as shown in FIGS. 1 and 3, the rocker arm 10 has one end in contact with the tip of the valve stem 22 of one intake valve, and the other end in contact with the rocker shaft. The first arm 24 is swingably supported by the rocker shaft 16, and the second arm 28 is in contact with the camshaft 26 and the cam surface 26a at one end, and is swingably supported by the rocker shaft 16 at the other end. The first arm 24 is
It has a branched part that branches into two ends, and is supported by a rocker shaft 16 at this branched part,
The supported portion of the rocker shaft of the second arm 28 is sandwiched therebetween. As shown in Figure 3, the second
A cylinder bore 30 is provided in the upper part of the arm 28 and extends in a direction perpendicular to the axial direction of the rocker shaft 16.
A plunger 32 is configured to slide inside the cylinder bore 30.
One end face of plunger 32 and cylinder bore 30
A spring 34 is press-fitted into the space formed by the plunger 32 and the first arm 24.
It is biased towards. The end surface of the plunger 32 opposite to the end surface that contacts the spring 34 is brought into contact with a stopper 24b provided at the tip of a protrusion 24a projecting upward from the first arm 24 due to the elastic force of the spring 34. Also, the second arm 2
8 is provided with a cavity 36 having a rectangular cross section and extending in the axial direction of the rocker shaft 16 across the cylinder bore 30, and a lock-off plate 38 slides within this cavity 36.
As shown in FIG. 2, the lock-off plate 38 is provided with a through hole 40.
0 is a large diameter portion 40a that is slightly larger than the diameter of the cylinder sliding portion 32a of the plunger 32 and the plunger 3.
The plunger 3 is smaller than the diameter of the sliding portion 32a of the plunger 3.
A small diameter portion 40b that is slightly larger than the small diameter portion 32b of No. 2
It consists of. Large diameter part 40a and small diameter part 40
b is formed to communicate in the sliding direction of the lock-off plate 38, that is, in the axial direction of the rocker shaft 16. The lock-off plate 38 is
As shown in FIG. 2, the arm portion 42a of a ring-shaped selector member 42 is rotatably supported by the rocker shaft 16. The selector member 42 is adapted to be moved in the axial direction of the rocker shaft 16 by a drive device 44. The drive device 44 is disposed between a casing 46 that forms a ring-shaped hydraulic chamber 45 around the rocker shaft, and the periphery of the casing 46 and the rocker shaft 16. It is provided with a piston 48 that can move in the direction, and a spring 50 that engages with a ring-shaped groove of a selector member 42 having a U-shaped cross section and presses the selector member 42 toward the piston 48. As shown in FIG. 1, hydraulic pressure is introduced into a hydraulic passage 54 in the casing 46 through a hydraulic pipe 52 extending parallel to the rocker shaft 16, and further led to a hydraulic chamber 45. When hydraulic pressure is not introduced into the hydraulic chamber 45, the piston 48 and the selector member 42 are pushed by the elastic force of the spring 50 and are placed in a position shifted to the right in FIG. At this time, the lock-off plate 38 is held at the position shown by the solid line in FIG. In this case, the center point of the large diameter portion 40a of the through hole 40 of the lock-off plate 38 coincides with the center of the plunger 32, and the plunger 32
can freely slide within the cylinder bore 30 via the cylinder bore 30.

When hydraulic pressure is introduced into the hydraulic chamber 45, the piston 48
moves to the left in FIG. 2, and the selector member 4
2 to the left and right against the elastic force of the spring 50. As a result, the lock-off plate 38
moves from the position shown by the solid line in FIG. 2 to the position shown by the imaginary line. In this position, the center of the small diameter portion 40b of the lock-off plate 38 is aligned with the plunger 32.
The small diameter portion 40 of the through hole 40 and the small diameter portion 32b of the plunger 32 engage with each other. This prevents the plunger 32 from sliding within the cylinder 30. The plunger 32 is the cylinder 30
If the first arm 24 can slide freely within the
The operating force from the second arm is not transmitted to the second arm 28, and only the second arm 28 rotates around the rocker shaft 16 while contacting the cam surface 25a. Therefore, in this state, the intake valve is maintained in the closed state regardless of the rotation of the camshaft 26. Also, plunger 3
2 is engaged with the small diameter portion 40b of the lock-off plate 38, the plunger 32 is connected to the cylinder 3.
Therefore, when the second arm 28 is rotated by the cam 26, the plunger 32
The tip of the cam transmits the operating force of the cam to the first arm 24 while being in contact with the stopper 24b of the first arm, causing the first arm 24 to rotate in conjunction with the second arm 28. That is, when the plunger 32 is engaged with the lock-off plate, it is in a locked state;
In this locked state, the first arm 24 and the second arm 28 rotate together around the rocker shaft, thereby transmitting the actuation force of the cam 26 to the stem 22 of the intake valve. Then, the opening and closing operations of the intake valve are performed.

In this example, the hydraulic pressure supply to the hydraulic chamber 45 of the drive device 44 is controlled according to the operating state. In a certain operating state, for example, when the intake air amount is small, the rotation is relatively low, and the load is low, the hydraulic pressure supply to the hydraulic chamber 45 is controlled to be stopped. As a result, only the second arm 28 rotates while contacting the cam surface 26a, and the tip of the plunger 32 is in contact with the stopper 24b of the first arm 24, resisting the elastic force of the spring 34 and rotating into the cylinder. Slide within 30. This state is an unlocked state, and one intake valve does not operate and remains closed regardless of the rotation of the cam. As a result, intake air is introduced into the combustion chamber only from the other intake port, so a high intake air flow rate can be obtained. Furthermore, during high rotation and high load, control is performed so that hydraulic pressure is introduced into the hydraulic chamber 45 of the drive device 44. As a result, the plunger 32 and the lock-off plate 38 are engaged to become locked, and the first arm 24 and the second arm rotate together around the rocker shaft in response to the movement of the cam 26. The intake valve is opened and closed at a predetermined timing. As a result, during high-speed, high-load operation, intake air is introduced from the two intake ports, so a sufficient amount of intake air can be ensured.

Note that in the drive device 44 of this example, the selector member 4
Since the rotary motion of the selector member is not transmitted to the piston 48 since the piston 2 and the piston 48 are constructed separately, the piston 48 and the casing 4 outside thereof
In addition to being able to suppress friction with 6 as much as possible,
Oil leakage within the hydraulic chamber 45 can be reduced. Further, since the selector member 42 is isolated from the hydraulic chamber 45, it is not necessary to have a hydraulic sealing function, and therefore the clearance between the selector member 42 and the rocker shaft 16 can be increased to reduce frictional resistance.

Furthermore, by securing the hydraulic pressure to the drive device 44 by dividing it from the main gear rally, it is possible to eliminate the need for separately providing an oil pump.

The above is an example in which the present invention is applied to valve control of a type having a plurality of intake ports, but the present invention can be similarly applied to other types of control.

(Effects of the Invention) According to the present invention, the rocker arm is controlled by hydraulic power, but since the hydraulic actuation mechanism is not built into the rocker arm, the structure can be extremely simple. At the same time, the Rotsuker arm can be made more compact. Therefore, the inertial weight of the rocker arm can be reduced, and the engine can be operated at high speeds without any problem. Further, since the drive mechanism and the selector member are supported by the rocker shaft, no special support structure is required and the structure can be made simple and compact. It also works reliably.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a valve train including a rocker arm according to the present invention, FIG. 2 is a cross-sectional view of the rocker arm and selector member drive device as seen in the rocker shaft axial direction, and FIG. 3 is a cross-sectional view of the rocker arm. . 10... Rocker arm, 16... Rocker shaft, 24... First arm, 28... Second arm, 30... Cylinder bore, 38... Lock-off plate, 42... Selector member, 44... Selector member drive device, 46...Casing, 48...
…piston.

Claims (1)

[Claims] 1 It has a first arm and a second arm that are swingably supported by a rocker shaft, the first arm has one end in contact with the stem end of the intake and exhaust valve, and the second arm has one end in contact with the cam surface of the camshaft. A locked state in which the first arm and the second arm are in contact with each other and integrally swing around the rocker shaft, and a non-locked state in which the second arm independently swings around the rocker shaft can be selectively achieved. a selector member having a locking member that moves in the axial direction of the rocker shaft to switch the rocker arm between a locked state and a non-locked state, and controls the movement of the selector member according to the operating state of the engine. and a drive mechanism, wherein the selector member is mounted so as to be movable at least in the axial direction of the rocker shaft in close proximity to a side portion of the rocker arm consisting of the first arm and the second arm on the rocker shaft. valve actuator.