JPS61175208A - Valve operating device in engine - Google Patents

Abstract

PURPOSE:To reduce the inertial mass of a rocker arm, by constituting a rocker arm with two sections, and by enabling the rocker arm to be rested in association with the axial shift of a selector member, and by forming one of the arm sections with a material having a low specific weight. CONSTITUTION:In an arrangement in which two intake valves disposed in each engine cylinder C are operated by two rocker arms 10, 12 while one exhaust valve is operated by a rocker arm 14, the rocker arm 10 for one of the intake valves, is composed of a first arm 24 which abuts against the front end of a valve stem and is made of S45C or the like, and a second arm 28 which abuts against a cam shaft and is made of aluminum or the like. A plunger 32 urged by a spring is fitted onto the first arm 24, and fits the small diameter section 40b of a lock-off plate 38 onto the small diameter section 32b of the plunger 32 to lock the arm 24 at the projecting extremity of the plunger 32 so that the intake valve is set in the operating condition. The above-mentioned plate 38 is integrally incorporated with a selector member 42 which is driven by hydraulic pressure fed into a hydraulic chamber 45.

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 interlock between an engine cam and a valve depending on the operating state.

(Prior Art) A structure 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 Application No. 57-182205, for one valve,
A valve driving device is disclosed that includes a rocker arm in which high-speed and low-speed cams are formed on a camshaft and has an abutting member that abuts each of these cams. In this disclosed device, the high-speed cam contact member that contacts the high-speed cam is configured to be slidable, and is provided with a stopper that prevents this sliding.

When the high-speed cam abutting member is prevented from sliding by the stopper, the high-speed cam operates the rocker arm, and when the high-speed cam abutting member is sliding, the low-speed cam operates the rocker arm. It is ready to be activated. Furthermore, the device of this Japanese Utility Model Application Publication No. 182205/1982 provides 1. It is equipped with a hydraulic actuator that uses engine oil flowing inside the rocker shaft, and by controlling the operation of this actuator according to the operating condition, the function of the high-speed cam or low-speed cam can be selectively exerted. The desired valve lift amount and valve timing are obtained.

(Problems to be Solved) However, in the device disclosed in Utility Model Application No. 57-182205, the high-speed cam abutting member is selectively created. Since the actuator is built into the rocker arm, the structure of the rocker arm becomes complicated and the inertial weight increases.
There is a problem that the valve jumps when the engine rotates at high speed, and undesirable results occur 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.

Valve operation of the present invention'+! The second position includes a rocker arm having a first arm and a second arm that are both swingably supported on the same tonneau car shaft. A first arm of the port/lug arm abuts the steno end of the intake and exhaust valves at one end, and a second arm abuts the cam surface of the camshaft at one end. And ”- Diary Soker Arm is the first
There is a 1':1 state where the arm and the second arm are integrated and swing around the rocker shaft, and a second state where the second arm swings around the rocker shaft 1- independently from the first arm. It is configured so that it can be selectively set to an unlocked state. Furthermore, the valve actuation device of the present invention includes:
A selector member having an opening/locking member that moves in the axial direction of the rocker shaft to switch between the opening/locking state and the unlocked state, and the operating state of the engine! , and a drive mechanism that controls movement of the selector member in response to the pull.

The first arm and the second arm of the present invention are made of different materials. In this case, the second arm
It is made of a material with a lower specific gravity than the arm.

(Function) 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 integrally formed. and 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 via the second arm and the first arm, and the intake and exhaust valves are opened and closed at predetermined timing. On the other hand, when the selector member moves in the axial direction of the rocker shaft and the locked state by the lock member is released, the operating force from the cam surface is only transmitted 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.

According to the present invention, the second arm, which is constantly rotated by cam operation, is made of a light material. For example, such a mechanism can be applied to an engine that obtains a desired output through so-called cylinder reduction operation, in which some cylinders are stopped during low-load engine operation, and only specific cylinders are operated. By configuring the valve train of the cylinder to stop,
The effect of reducing bombing loss and improving fuel efficiency can be obtained. 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 2 cylinders.
It has two intake ports and one exhaust port, and a rocker arm 10.12 for the two intake valves is connected to each intake valve in order to operate the two intake valves for opening and closing the intake ports. be combined. Further, an exhaust valve rocker arm 14 is provided to open and close the exhaust valve.

The intake valve rocker arm 1.0.12 and the exhaust valve rocker arm 14 are swingably supported by a rocker shaft 16.18 extending in the column direction of the cylinders C.

One intake valve rocker arm 12 and one exhaust valve rocker arm 1 have the structure and function of a normal rocker arm. Regarding the other intake valve rocker arm 10, 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 has a first arm 24 that is swingably supported on the Illustrator shaft 16.
Then, one end contacts the force surface 26a of the camshaft 26, and the other end +II! The second arm 28 is swingably supported by the rotocar shaft L1.6. First arm 24
has a bifurcated portion at its end, and is supported by the rocker shaft 16 at this bifurcated portion, sandwiching the supported portion of the rocker shaft 16 of the second arm 28 . That is, the first arm 24 and the second arm 28 are in sliding contact with each other at the side end surfaces of the supported portion by the rocker shaft. The first team 24 and the second arm 2B in this example are made of 345C and aluminum, respectively, and therefore, they are made of different materials and the second arm 28 is lightweight. As shown in Figure 3, the second
A cylinder bore 30 extending in a direction perpendicular to the axial direction of the rocker shaft 16 is formed in one part of the arm 28, and a plunger 32 is inserted into the cylinder bore 30.
is designed to slide. A spring 34 is press-fitted into a space formed by one end of the plunger 32 and the cylinder bore 30, and a spring 34 is inserted into the space formed by one end of the plunger 32 and the cylinder bore 30.
The arm 24 is biased toward the arm 24. The end surface of the plunger 32 opposite to the end that contacts the spring 34 contacts a stopper 24b provided at the tip of the projection 24a projecting upward from the first arm 24 due to the elastic force of the spring 34. Further, the second arm 28 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.
6, the lock-off plate 38 is connected to the rocker shaft 16.
It is designed to slide in the axial direction. As shown in FIG. 2, the lock-off plate 38 has a pierced i! 7040, and this one through hole 4o has a large diameter portion 40 that is slightly larger than the diameter of the cylinder sliding portion 32a of the plunger 32.
a, and a small diameter portion 40b that is smaller than the diameter of the tr1 moving portion 32a of the plunger 32 and slightly larger than the small diameter portion 32b of the plunger 32. Large diameter part 40a and small diameter part 4
0b is formed to communicate in the rocking direction of the lock-off plate 38, that is, in the axial direction of the rocker shaft 16. As shown in FIG. 2, the lock-off plate 38 includes an arm fJT+ of a ring-shaped selector member 42 rotatably supported around the rocker shaft 16.
42 a. The selector member 42 is configured 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 1 and the circumferential surface of the rocker shaft 16, and is arranged along the circular surface of the rocker shaft 160. , a piston 48 movable in the axial direction of the shaft 16, 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. There is. As shown in Figure 1, the oil pressure is applied to the rocker shaft 1
The oil is introduced into a hydraulic passage 54 in the casing 46 through a hydraulic pipe 52 extending parallel to the hydraulic pipe 6 , 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 500, and are placed in a position shifted to the right in FIG.

At this time, the lock-off plays 1 and 38 are held at the positions shown by solid lines in FIG. In this case, the center point of the large diameter portion 40a of the one 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 large diameter portion 40a of the plunger 32. can do.

The piston 48 through which hydraulic pressure is introduced into the hydraulic chamber 45 moves to the left in FIG.
Move it to the left against an elastic force of 0. As a result, the lock-off play 1 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 coincides with the center of the plunger 32, and the small diameter portion 40b of the through hole 40 and the small diameter portion 32b of the plunger 32 are engaged. As a result, the sliding movement of the plunger 32 within the cylinder 30 is 1 (11
will be stopped. When the plunger 32 can freely slide within the cylinder 30, the actuation force from the second arm is not transmitted to the first arm 24, and only the second arm 28 is connected to the cam surface 25.
It rotates around the rocker shaft 16 while contacting the rocker shaft 16. Therefore, the intake valve remains closed regardless of the rotation of the camshaft 26. On the other hand, when the plunger 32 is engaged with the small diameter portion 40a of the lock-off plate 38, the plunger 32 cannot move within the cylinder 30, so when the second arm 28 is rotated by the cam 26, , the tip of the plunger 32 is connected to the stopper 24 of the first arm.
While in contact with b, the operating force of the cam is transmitted to the first arm 24 and rotated in conjunction with the first arm 24 and the second arm 28. That is, the plunger 32 is in lock-off play 1.
When the cam 26 is engaged, it is in a locked state. In this locked state, the first arm 24 and the 27th arm 28 rotate together around the rocker shaft, thereby controlling the operation of the cam 26. Power is transmitted to the stem 22 of the intake valve;
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 connected to the stopper 24 of the first arm 24. b and slides in the cylinder 30 against the elastic force of the spring 34. This state is an unlocked state, and one intake valve is not operated and remains closed regardless of the rotation of the cup 2. As a result, since intake air is introduced into the combustion chamber only from the other intake boat, 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 and become locked, and the first arm 24 and the second arm
The arm integrally rotates around the rocker shaft in accordance with the movement of the cam 26, and opens and closes the intake valve at a predetermined timing. As a result, during high-speed, high-load operation, intake air is introduced from the two intake boats, so a sufficient amount of intake air can be ensured.

In the drive device 44 of this example, since the selector member 42 and the piston 38 are configured separately, the rotational motion of the selector member is not transmitted to the piston 38.
Not only can friction between the hydraulic pressure chamber 45 and the outer casing 46 be suppressed as much as possible, but also oil leakage within the hydraulic chamber 45 can be reduced. In addition, the select member 42 is connected to the hydraulic chamber 4.
Since it is isolated from the rocker shaft 5, there is no need to provide a hydraulic sealing function, and therefore, the clearance between the rocker shaft 16 and the rocker shaft 16 can be increased to reduce frictional resistance.

Furthermore, by securing the hydraulic pressure to the drive unit Wt 4.4 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 a type of valve control having a plurality of intake boats, 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 rocker arm can be made more compact.

Therefore, the inertial weight of the rocker arm can be reduced and the engine can be operated at +14 revolutions without any problem. Furthermore, since the drive mechanism and the selector members are supported by the rocker shaft, no special support structure is required, and the structure can be made compact within the cylinder. It also works reliably.

Sara? ,'',, In the present invention, since the first arm and the second arm are made of different materials, it is possible to prevent the sliding portions of each other from seizing during relative rotation.

In addition, since the second arm, which can be constantly rotated between the locked and unlocked states, is made of a light material, the weight is reduced, so the inertial weight of the second arm is reduced.
As a result, the rotational resistance of the camshaft when the lock is unlocked can be reduced, and the rotation range of the engine can be increased.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a valve mechanism including a rocker arm according to the present invention, FIG. 2 is a sectional view of the rocker arm and selector member drive device as seen in the axial direction of the rocker shaft, and FIG.
The figure is a horizontal folded view of the rocker arm. DESCRIPTION OF SYMBOLS 10...Rocker arm, 16...Rocker shaft, 24...m], 7-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] It has a first arm and a second arm that are swingably supported on 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. Select a locked state in which the first arm and the second arm are in contact and integrally swing around the rocker shaft, and an unlocked state in which the second arm independently swings around the rocker shaft. 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 an unlocked state; A drive mechanism for controlling movement of a selector member, wherein the second arm is made of a material having a smaller specific gravity than the first arm.