JP3564727B2 - Engine Valve Actuator - Google Patents

Description

[0001]
[Industrial applications]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating device for an engine, and more particularly to a valve operating device for an engine in which a valve lift characteristic is switched between a low rotation and a high rotation of the engine.
[0002]
[Prior art]
Conventionally, in order to achieve both high torque characteristics during low-medium speed operation and improved output during high-speed operation, the lift characteristics of the intake valve or the exhaust valve are changed according to the operation state. Alternatively, it is known to control the amount of intake and exhaust (see, for example, JP-A-63-167016 and JP-A-63-57805).
[0003]
In these, a low-speed rocker arm having a swinging tip abutting on a valve and a high-speed rocker arm which is a free cam follower provided between the low-speed rocker arm and having no contact portion with the valve swing on a common rocker shaft. The low-speed rocker arm is slidably contacted with a low-speed cam, and the high-speed rocker arm is slidably contacted with a high-speed cam having a profile in which the valve opening angle or valve lift is larger than that of the low-speed cam. .
[0004]
In the rocker arm for high speed and the rocker arm for low speed, a fitting hole is formed in a swinging part separated by a predetermined distance from the rocker shaft in a direction parallel to the rocker shaft, and the inside of the fitting hole is formed. The three rocker arms are connected or disconnected when the plunger is fitted into or removed from the fitting hole in response to the operating oil pressure. A mechanism is provided.
[0005]
[Problems to be solved by the invention]
However, in such a conventional valve operating device, the sub-rocker arm for the high-speed cam follower attached to the main rocker arm is connected to or disconnected from the main rocker arm so that the valve lift characteristics between low-speed rotation and high-speed rotation are obtained. However, play may occur in the connecting portion due to variations in dimensional accuracy and the like, so that when the connecting state is established, a gap may be generated in the connecting portion between the sub rocker arm and the main rocker arm . Therefore, when the lift via the connecting portion from the sub-rocker arm to the main rocker arm is transmitted by the high-speed cam, impact load is applied to the abutting portion of the consolidated portion, giving abnormal wear, jump during opening and closing operation of the valve There is a possibility that abnormal movement such as this may occur.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to focus on the above problem, and to solve the problem, a contact portion when a sub rocker arm (second rocker arm) for a high-speed cam follower and a main rocker arm (first rocker arm) are coupled by (coupling switching means). An object of the present invention is to provide a valve operating device for an engine in which an input load for a stable valve lift can always be transmitted to a valve from a cam without generating a gap, and an abnormal operation can be prevented from occurring. .
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a first rocker arm that is swingably supported by a rocker shaft and has a distal end linked to an intake valve or an exhaust valve and is driven by a first cam. Rutotomoni is swingably supported on the rocker arm is biased toward the second cam by a spring, and a second rocker arm driven by a second cam, pivotably supported on said first rocker arm, the second A coupling switching lever member rotatable between a first position for coupling the two rocker arms with the first rocker arm and a second position for disengaging the rocker arm, wherein the coupling switching lever member is in the second position. is configured so that a gap is maintained between the second rocker arm and the base circle portion of the second cam when in, upon rotation to the first position of the coupling switching lever member, the As engaging end of edged changeover lever member is engaged with the second rocker arm while pushing up the second rocker arm to said second cam side, which is characterized in that the relative position therebetween is set It is.
[0008]
[Action]
According to the present invention, when the coupling switching lever member rotates from the second position to the first position, the engagement end of the coupling switching lever member engages with the second rocker arm while pushing the second rocker arm toward the second cam. Combine . Thus, the coupling state between the first rocker arm and the second rocker arm, coupling the control lever member and rather greens that gap is formed between the second rocker arm, both of collision when the lift by the second cam has started prevented Is done.
[0009]
【Example】
Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.
[0010]
1 to 5 show one embodiment of the present invention.
[0011]
Note that the present embodiment is a case where the present invention is applied to an engine provided with two valves (either an intake valve or an exhaust valve, the illustrated one being an intake valve) having the same function for one cylinder. Is shown. That is, each cylinder is provided with a single main rocker arm (first rocker arm) 1 corresponding to two intake valves 2, and the base end of the main rocker arm 1 is a hollow main rocker shaft 3 common to each cylinder. The main rocker arm 1 has a bifurcated distal end 1A abutting on the stem top of the intake valve 2.
[0012]
The main rocker arm 1 is formed substantially bifurcated in a plan view, and a low-speed cam follower 4 is provided substantially above the center of each of the arms 1E, 1E formed bifurcated of the main rocker arm 1.
[0013]
Reference numeral 5 denotes a sub rocker arm (second rocker arm) which is swingably supported by a support shaft 6 above a crotch formed at the fork of the main rocker arm 1, and 7 denotes a high-speed cam follower provided at an end of the sub rocker arm 5. is there. The high-speed cam follower 7 and the two low-speed cam followers 4 are arranged in the axial direction of the cam shaft 8 as shown in FIGS. 9 and 10 are a high-speed cam (second cam) and a low-speed cam (first cam) formed integrally with the camshaft 8, and the high-speed cam follower 7 and the low-speed cam follower 4 Each is driven by sliding contact.
[0014]
Next, the high / low speed switching mechanism according to the present invention will be described with reference to FIGS.
[0015]
4 (A), (B) and FIG. 5 show the low-speed operation state, and FIG. 4 (C) shows the high-speed operation state. 4, 5B is a first plunger storage hole drilled in the sub rocker arm 5, 1B is a second plunger storage hole drilled in the main rocker arm 1, and 1C shown in FIG. 3 is a third plunger storage hole. 21 is a first plunger slidably fitted in the first plunger storage hole 5B, 22 is a spring for biasing the tip of the first plunger 21 toward the butting portion 1D of the main rocker arm 1, and 23 is a spring. The stopper ring 24 that regulates the stroke of the first plunger 21 is an air vent.
[0016]
On the other hand, an oil passage 25 for guiding oil from an oil passage 3A provided at the center of the rocker shaft 3 communicates with the second plunger housing hole 1B, and the second plunger is slidably held in the housing hole 1B. The plunger 26 is inserted. Reference numeral 11 denotes a lever member, which is supported by the main rocker arm 1 on a lever support shaft 12 so as to be swingable. Reference numeral 13 denotes an engagement end provided at one end of the lever member 11, and reference numeral 11B denotes an operating end that contacts the second plunger 26. 4B is a third plunger slidably held in the third plunger housing hole 1C, and 28 is directed to the projection 11A (see FIG. 1) provided on the lever member 11 with the third plunger 27. The spring is biased. In a low-speed operation state as shown in FIG. 5A, the clearance S is maintained between the base circle portion 9A of the high-speed cam 9 and the high-speed cam follower 7. . The gap S is set such that the engagement end 13 of the lever member 11 can push up the sub rocker arm 5 even when the base circle portion 9A of the high-speed cam 9 faces the high-speed cam follower 7. Further, when the locking portion 5A of the sub rocker arm 5 engages with the engagement end 13 of the lever member 11 as shown in FIG. 5B, the engagement end 13 pushes the sub rocker arm 5 up. It is set so as to be operated slightly, and both corners are chamfered or curved so that the above operation can be performed smoothly.
[0017]
Subsequently, the valve operation at the time of high-speed operation and at the time of low-speed operation according to the present embodiment will be described with reference to FIGS. 4 (A) to 4 (C) and FIGS. 5 (A) and 5 (B).
[0018]
When a low-speed operation is performed as shown in FIG. 5A or FIGS. 4A and 4B, hydraulic pressure is supplied to the second plunger 26 via the oil passage 3A of the rocker shaft 3. 4B, the lever member 11 is rotated clockwise by the third plunger biased by the spring 28 as shown in FIG. 4B, and the locking portion 5A of the sub rocker arm 5 and the lever member 11 are rotated. The engagement end 13 is kept at the disengaged position. Thus, the sub rocker arm 5 is allowed to swing with respect to the main rocker arm 1, and even if the high speed cam 9 slides on the high speed cam follower 7 in FIG. The lift by the high-speed cam 9 is not transmitted to the valve shaft 2A merely by absorbing the cam profile, while the low-speed cam 10 slides on the low-speed cam follower 4, so that the valve shaft 2A of the valve 2 is lifted by the lift by the low-speed cam 10. Operate.
[0019]
At the time of high-speed operation, a control unit (not shown) supplies oil pressure to the oil passage 3A via oil pressure supply means, and the second plunger 26 is stored in the second plunger 26 as shown in FIG. By projecting from the chamber 1B and pressing the operating end 11B of the lever member 11, the lever member 11 is rotated in a counterclockwise direction. In this case, the lever member 11 operates so as to push the third plunger 27 back into the third plunger housing hole 1C against the spring force of the spring 28, and as shown in FIG. The mating end 13 is engaged with the locking end 5A so as to push up the sub rocker arm 5. In addition, such a push-up is made possible by the gap S described above.
[0020]
Thus, during the switching operation from low-speed rotation to high-speed rotation, there is no gap between the engagement end 5A of the sub rocker arm 5 and the engagement end 13 of the lever member 11, so that the engagement of the sub rocker arm 5 does not occur. The toe 5A and the engagement end 13 of the lever member 11 are always kept in contact. Therefore, even if the lift of the high-speed cam 9 is started during the transition of the switching operation, the engaging end 5A of the sub rocker arm 5 does not collide with the engaging end 13 of the lever member 11, and the engaging end 13 of the lever member 11 The impact load to be received can be prevented beforehand, and abnormal wear and hammering noise can be prevented between the two sliding contact portions, and abnormal operation of the valve lift can be prevented.
[0021]
When switching from high-speed rotation to low-speed rotation, the hydraulic pressure supplied to the oil passage 3A is stopped, and the third plunger 27 rotates the lever member 11 clockwise by the spring force of the spring 28. . Therefore, the engagement end 13 of the lever member 11 is pulled off from the engagement end 5A of the sub rocker arm 5, and a low-speed operation state as shown in FIG.
[0022]
In the embodiment described above, an example of application to an engine having two valves having the same function in one cylinder is described. However, application of the present invention is not limited to such an engine. For example, it goes without saying that the present invention can be applied to an engine in which one intake valve and one exhaust valve are provided for one cylinder.
[0023]
【The invention's effect】
As described above, according to the present invention, when the coupling switching lever member rotates from the second position to the first position, the engagement end of the coupling switching lever member moves the second rocker arm toward the second cam. Since the first rocker arm is engaged with the second rocker arm while being pushed up, no gap is formed between the coupling switching lever member and the second rocker arm in a state where the first rocker arm and the second rocker arm are coupled. Therefore, the cam input load transmitted from the second cam to the second rocker arm does not act as an impact load and acts between the coupling switching lever member and the second rocker arm, and the stable cam input load is always transmitted to the valve. In addition, it is possible to prevent abnormal wear and hitting noise between the engaging portions of the lever member and the second rocker arm, thereby contributing to prevention of abnormal valve lift operation.
[Brief description of the drawings]
FIG. 1 is a side view showing a configuration of an embodiment of the present invention.
FIG. 2 is a top view excluding the cam device of the embodiment shown in FIG.
FIG. 3 is a front view of the embodiment shown in FIG. 1;
FIG. 4 is a sectional view taken along the line AA in FIG. 2 and FIG. 1B along the line BB in FIG. 1 showing the valve operating state at the time of low lift according to the embodiment shown in FIG. FIG. 3 is an explanatory view showing a valve operating state of FIG.
FIG. 5 is an explanatory diagram showing a valve operating state of the embodiment shown in FIG. 1 at the time of a low lift, with the state diagram (A) and an enlarged view (B) of a portion P in FIG.
[Explanation of symbols]
1 Main Rocker Arm 1A (Arm) Tip 1B Second Plunger Storage Hole 1C Third Plunger Storage Hole 1D Abutment 1E Arm 2 (Intake) Valve 3 Rocker Shaft 3A Oil Passage 4 Low Speed Cam Follower 5 Sub Rocker Arm 5A Lock 6 Support shaft 7 High-speed cam follower 8 Cam shaft 9 High-speed cam 10 Low-speed cam 11 Lever member 11A Projection 11B Working end 12 Lever support shaft 13 Engaging end 21 First plunger 22, 28 Spring 25 Oil passage 26 Second plunger 27 Third plunger S gap

Claims (1)

A first rocker arm that is swingably supported by the rocker shaft and has a distal end linked to an intake valve or an exhaust valve and is driven by a first cam;
A second rocker arm that Rutotomoni is swingably supported on said first rocker arm is biased toward the second cam by a spring, and is driven by a second cam,
A coupling switching lever member rotatably supported by the first rocker arm and rotatable between a first position for coupling the second rocker arm with the first rocker arm and a second position for disengaging the second rocker arm; With
When the coupling switching lever member is at the second position, a gap is maintained between a base circle portion of the second cam and the second rocker arm,
During rotation in the first position of the coupling switching lever member, as engaging end of said binding edged changeover lever member is engaged with the second rocker arm while pushing up the second rocker arm to said second cam side, A valve operating device for an engine, wherein a relative position between the two is set .

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