JPS61175206A - Valve operating device in engine - Google Patents

Abstract

PURPOSE:To simplify the arrangement of a valve operating mechanism, by constituting a rocker arm with two sections, which may be rest when a selector member shifts in the axial direction of the rocker arm, and by operating the selector member with the use of hydraulic pressure from an independent hydraulic passage. 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 a second arm 28 which abuts against a cam shaft. Meanwhile, 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 made to be movable. The above-mentioned plate 38 is provided integrally with a selector member 42 which is slid by hydraulic pressure fed into a hydraulic chamber 45 from a pipe line 52 through a hydraulic passage 54.

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 mechanism for selectively stopping the interlocking state of a cam and a valve of a specific valve operating mechanism of an engine depending on the operating state, for example, a valve operating stop mechanism is known. For example, Japanese Utility Model Application Publication No. 57-182205 discloses, for one valve, a rocker arm having high-speed and low-speed cams formed on the camshaft and an abutting member that abuts on each of these cams. A valve drive device is disclosed. 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. If the high-speed cam abutting member is prevented from sliding, the high-speed cam operates the rocker arm, and if the high-speed cam abutting member is sliding, the low-speed cam operates the rocker arm. The rocker arm can be activated. Furthermore, the device of this Utility Model Application Publication No. 57-182205 is equipped with a hydraulic actuator that utilizes the engine oil flowing in the rocker shaft in order to control the stopper; By controlling the operation according to the operating condition, the cam for quotient) or ((((
The function of the i* cam is selectively exerted to obtain the desired valve lift amount and valve timing.

(Problems to be Solved) However, in the device disclosed in the above-mentioned Japanese Utility Model Application Publication No. 57-182205, a hydraulic actuator is used to control a stopper for selectively operating the high-speed cam abutting member.

Since the eta is built into the rocker arm, the structure of the rocker arm becomes complicated, the inertia becomes large, and there are problems such as valves jumping at high engine speeds, as well as problems with vibration and durability. However, undesirable consequences occur. Furthermore, since the hydraulic pressure to the actuator is secured from the engine oil for lubrication of the rocker shaft that flows within the rocker shaft, there is also the problem that the amount of oil leakage increases.

(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. The first arm of the rocker arm is in contact with the stem end of the intake and exhaust light at one end, and the second arm is in contact with the stem end of the intake and exhaust light.
The arm abuts the cam surface of the camshaft at one end. The rocker arm 1- is composed of a first arm and a second rocker arm.
A locked state in which the second arm swings around the rocker shaft while being integrated with the arm, and an unlocked state in which the second arm swings around the rocker shaft independently from the first arm can be selectively achieved. +1. Y has been completed. Further, the valve actuating device of the present invention includes a selector member having 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 selector member that changes the selector member according to the operating state of the engine. It is equipped with a drive mechanism that controls movement.

The hydraulic pressure for driving the hydraulic drive mechanism is introduced through a hydraulic pressure supply passage provided separately from the rocker arm lubrication oil passage provided within the rocker shaft.

(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 through the second arm and the first arm, and the
I" opens and closes at a 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. It is not transmitted to the second arm.In other words, in this unlocked state, the second arm swings around the rocker arm independently from the first arm while contacting the cam surface, and the first arm is in a stopped state. The intake and exhaust valves are therefore kept closed.

The hydraulic drive mechanism provided to control the above-mentioned operation of the selector member is supplied with oil pressure via a hydraulic passage provided separately from the oil supply oil provided in the rocker shirts 1 to 1. Hydraulic pressure is introduced into the hydraulic drive mechanism provided for this purpose through a hydraulic passage provided separately from the oil supply passage provided within the rocker shaft. The oil inside is used only for rocker arm lubrication.

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 valve train to stop for a cylinder that is stopped, it is possible to reduce the pumping loss and improve fuel efficiency.

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 maintain a desired intake flow rate.

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

Referring to FIG. 1, each cylinder C, 2 of the engine of this example
It has two intake boats and one exhaust port, and a rocker arm 10.12 for the two intake valves is assembled for each intake valve in order to operate the two intake valves for opening and closing the intake boat. be combined. In addition, an exhaust valve rocker arm 4 is provided to open and close the exhaust valve.

The intake valve rocker arm 10.12 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 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 1o
The first arm 24 contacts the tip of the valve stem 22 of one intake valve at one end and is swingably supported by the rocker shaft 16 at the other end, and the first arm 24 contacts the camshaft 26 and the cam surface 26a at one end. and a 27th arm 28 which is swingably supported by the rocker shaft 16 at the other end. The first arm 24 has a bifurcated portion at its end, is supported by the rocker shaft 16 at this bifurcated portion, and holds the supported portion of the rocker shaft 16 of the second arm 28 between them. As shown in FIG. 3, a cylinder bore 30 is formed in the upper part of the second arm 28 and extends in a direction perpendicular to the axial direction of the rocker shaft 6.
2 is designed to slide. A spring 34 is press-fitted into a space formed by one end surface of the plunger 32 and the cylinder bore 30, and urges the plunger 32 toward the first arm 24. Plunger 32
The end surface opposite to the end surface that contacts the spring 34 contacts a stopper 24b provided at the tip of the projection 24a projecting upwardly of 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 in the axial direction. As shown in FIG. 2, the lock-off plate 38 is provided with a through hole 40, which has a large diameter portion 40a that is slightly larger than the diameter of the cylinder sliding portion 32a of the plunger 32, and a large diameter portion 40a that is slightly larger than the diameter of the cylinder sliding portion 32a of the plunger 32. A small diameter portion 40b that is smaller than the diameter of the sliding portion 32a of the plunger 32 and slightly larger than the small diameter portion 32b of the plunger 32.
It consists of. The large diameter portion 40a and the small diameter portion 40b are formed to communicate in the sliding 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 is coupled to an arm portion 42a of a ring-shaped selector member 42 rotatably supported around the rotocar shaft 1-16. 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 includes a casing 46 that forms a ring-shaped hydraulic chamber 45 around the rocker shaft 16.
a piston 48 disposed between the casing 46 and the periphery of the rocker shaft 16 and movable in the axial direction of the shaft 16 along the circumferential surface of the rocker shaft 16; and a selector having an opening-shaped cross section. A spring 50 is provided which engages with the ring-shaped groove of the member 42 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 no hydraulic pressure is 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 402 of the through-hole 40 of the mouth/7-off plate 1/38 coincides with the center of the plunger 32, and the plunger 32 freely moves inside the cylinder bore 30 via this large-diameter portion 40a. Can be slid. When hydraulic pressure is introduced into the hydraulic chamber 45, the piston 48 moves to the left in FIG. 2, and the selector member 42 is moved to the left against the elastic force of the spring 50. As a result, lock-off play 1-38 is
It moves from the position shown by the solid line in FIG. 2 to the position shown by the imaginary line. In this position, the small diameter portion 4. of the lock-off plate 38. The center of Ob coincides with the center of the plunger 32, and the small diameter portion 4. Ob 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. When the plunger 32 can freely slide within the cylinder 30, the operating force from the second arm is not transmitted to the first arm 24, and only the second arm 28 contacts the cam surface 25a while the rocker shaft 16 rotate around. Therefore, in this state, the intake valve is maintained in the closed state regardless of the rotation of the camshaft 26. Further, the plunger 32 is connected to the small single thread portion 40b of the lockoff plate 38
When the plunger 32 is engaged with the cylinder 30
Therefore, when the second arm 28 is rotated by the cam 26, the tip of the plunger 32 moves inside the first arm.
The actuating force of the cam is transmitted to the first arm 24 while in contact with the arm's latch 24b, and the first arm 24 is rotated in conjunction with the second arm 28. That is, plunger 3
2 is engaged with the lock-off plate, it is in a locked state, and in this locked state, the first arm 24 and the second arm 24 are engaged with the lock-off plate.
The arm 28 rotates around the rocker shaft in unison with the arm 28, thereby transmitting the operating force of the cam 26 to the stem 22 of the intake valve, thereby opening and closing the intake valve.

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 amount of intake air 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 plunger 32
The tip of the first arm 24 slides in the cylinder 30 against the elastic force of the spring 34 while being in contact with the stopper 24b of the first arm 24. This state is an unlocked state, and one intake valve does not operate and remains closed regardless of the rotation of the cam. This result 1. 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 to become locked, and the first arm 24 and the second arm rotate together around the rocker shaft according to the movement of the cam 26, and the intake air Open and close the valve at predetermined timing. As a result, during high-speed, high-load operation, intake air is introduced from the two intake boats,
Sufficient intake air volume can be secured.

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.
It is possible to suppress the friction between the casing 46 and the outer casing 46 as much as possible, and also to reduce oil leakage in the hydraulic chamber 45. Further, the selector member 42 is connected to the hydraulic chamber 4
5, there is no need to provide a hydraulic sealing function, and therefore the clearance between the rotocarshaft 1 and 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 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 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.

Furthermore, in the present invention, the hydraulic pressure supply passage for the hydraulic drive device 44 is provided separately from the oil passage for rocker shaft lubrication in the rocker shaft, and the hydraulic pressure for direct driving is ensured by this specially provided hydraulic pressure supply passage. This reduces the amount of oil leakage compared to when the hydraulic passages are shared. Therefore, a capacity amplifier for the oil pump is not required.

[Brief explanation of drawings]

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 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.Old...Selector member drive device, 46.Old...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; An engine comprising: a hydraulic drive mechanism that controls movement of a selector member; and a hydraulic pressure supply passage to the drive mechanism that is provided separately from a rocker arm lubrication oil passage provided in a rocker shaft. valve actuator.