JP2014159797A - Variable valve mechanism of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably switch from a non-connecting state to a connecting state even when a position of a pin hole of an input arm is not determined in contact with a base circle.SOLUTION: An arm position correcting mechanism 60 is disposed to prevent difficulty in displacement from a non-connecting position to a connecting position, of pins 25, 35 caused by that positions of both pin holes 25, 35 are not aligned in contact with a base circle in a non-connecting state, as a position of the pin hole 25 of an input arm 20 in contat with the base circle, is not determined caused by displacement of the position of the input arm 20 in the oscillating direction in contact with the base circle, when the position of the input arm 20 in contact with a nose, is displaced in the oscillating direction by an operation angle variable device 40. The arm position correcting mechanism 60 displaces the position of an output arm 30 to be aligned with the position of the input arm 20 in the non-connecting state, thus the positions of both pin holes 25, 35 in contact with the base circle in the non-connecting state, are aligned.

Description

  The present invention relates to a variable valve mechanism that switches a connection state of valves in accordance with an operation state of an internal combustion engine.

  Among the variable valve mechanisms of the internal combustion engine, like the variable valve mechanism 90 of the conventional example shown in FIG. 8 (Patent Document 1), the valve 7 is driven to swing by being driven by the cam 95. By interposing between the swing arm 92 and the cam 95 and the swing arm 92, the position of the swing arm 92 when the nose 97 of the cam 95 contacts is displaced in the swing direction. Some of them are configured to include a working angle varying device 94 that changes the working angle of the valve 7.

Japanese Patent Laid-Open No. 2006-77089

  According to the variable valve mechanism 90 of the conventional example, the operating angle of the valve 7 can be continuously changed by the operating angle variable device 94 as necessary, so that both low fuel consumption and high output can be achieved. However, the present inventor wanted to further improve fuel consumption.

  Therefore, the present inventor considered that the variable valve mechanism 90 of the conventional example is changed to the variable valve mechanism 100 of the reference example shown in FIG. 9, and the driving of the valve 7 is stopped when it is unnecessary. That is, the conventional swing arm 92 is divided into an input arm 102 and an output arm 103, and the input arm 102 is swung by being driven by a cam 95, and at the time of nose contact by the operating angle variable device 94. The output arm 103 is configured to swing together with the input arm 102 to drive the valve 7 when connected to the input arm 102. Further, pin holes 107 and 108 are provided in the input arm 102 and the output arm 103, respectively, and a switching device 105 having a pin 106 is provided, and the pin 106 is connected to both pin holes 107 as shown in FIG. , 108 is displaced to a coupling position that straddles the valve 7 to switch to a coupling state in which the valve 7 is driven, and as shown in FIG. 9C, both pin holes 107, 108 are displaced to a non-coupling position that does not straddle. Then, the valve 7 is switched to a non-connected state in which the driving of the valve 7 is stopped.

  According to the variable valve mechanism 100 of this reference example, the operating angle of the valve 7 can be continuously changed by the operating angle variable device 94, and the connected state in which the valve 7 is driven by the switching device 105 and the driving of the valve 7. It is also possible to switch to a non-connected state that pauses. However, it is expected that the following problems will occur. That is, when the position of the input arm 102 at the time of nose contact is shifted in the swing direction by the operating angle varying device 94, the position of the input arm 102 at the time of base circle contact with which the base circle 96 of the cam 95 contacts is also in the swing direction. Therefore, the position of the pin hole 107 of the input arm 102 when the base circle is in contact is not fixed. Therefore, as shown in FIG. 9C, in the non-connected state, the positions of the pin holes 107 and 108 of both arms 102 and 103 are not aligned when the base circle contacts, and the pin 106 is displaced from the non-connected position to the connected position. It becomes difficult to do. This is because even if the positions of the pin holes 107 and 108 of both arms 102 and 103 are aligned at a timing other than when the base circle is in contact (at the time of nose contact), the timing is instantaneous. This is because it is difficult for 106 to be displaced. Therefore, it is not possible to stably switch from the unconnected state to the connected state.

  Therefore, the operating angle of the valve can be continuously changed by the operating angle varying device, and the switching device can be switched between a connected state in which the valve is driven and a non-connected state in which the driving of the valve is stopped, and the base circle An object is to stably switch from a non-connected state to a connected state even if the position of the pin hole of the input arm at the time of contact is not fixed.

  To achieve the first object, the variable valve mechanism of the internal combustion engine of the present invention swings with an input arm that swings when driven by a cam, and swings together with the input arm when connected to the input arm. Switch to the connected state that drives the valve by displacing the pin to the connecting position that straddles the pin hole of both the input arm and the output arm to drive the valve, and it does not straddle both pin holes A switching device that switches to a non-coupled state in which the drive of the valve is stopped by displacing the pin to a position, and an input arm at the time of nose contact that is interposed between the cam and the input arm and that contacts the nose of the cam When the position is displaced in the swing direction, the operating angle variable device that changes the operating angle of the valve in the connected state, and the position of the input arm at the time of nose contact in the operating angle variable device is displaced in the swing direction. The cam The position of the input arm when the base circle is in contact with the base circle is also displaced in the swing direction, so that the position of the pin hole of the input arm when the base circle is in contact is not fixed. To prevent the holes from becoming aligned when the base circle contacts, and thus making it difficult for the pin to move from the unconnected position to the connected position, the position of the output arm is displaced to align with the position of the input arm in the unconnected state. And an arm position correction mechanism that aligns the positions of both pin holes when the base circle is in a non-connected state.

  The arm position correction mechanism is not particularly limited, but includes a latching portion provided on the side surface of the one arm of the input arm and the output arm that is closer to the swing direction than the opening of the pin hole of one arm, and is not connected Position of both pin holes when the base circle is in a non-connected state so that the output arm is displaced with the input arm by hooking the tip of the pin protruding from the pin hole of the other arm to the latching part in the state Are preferably aligned.

  More specifically, the arm position correction mechanism includes a guide groove that is recessed in the side surface of one arm and extends in a swinging direction from the front of the opening of the pin hole of the arm, and the latching portion is an end of the guide groove. It is preferable to form in the part. This is because it is easy to guide the pin to the latching portion and the pin hole.

  The pin is not particularly limited, and includes a cylindrical outer pin and an inner pin provided on the inner side of the outer pin, and the tip of the outer pin protruding from the pin hole of the other arm is hooked on the latching portion. Therefore, it is preferable that the tip of the inner pin enters the pin hole of one arm as the inner pin advances from the inside of the outer pin. This is because the friction between the pin and the latching portion can be reduced, whereby the pin can be smoothly displaced from the unconnected position to the connected position.

  The lost motion mechanism or the like is not particularly limited, but the variable valve mechanism includes a valve spring that urges the valve in the closing direction, a first lost motion spring that urges the input arm to the cam, and an output arm that is attached to the valve. It is preferable to provide a second lost motion spring that is weaker than either the valve spring or the first lost motion spring. This is because the output arm can be quickly returned to the predetermined rest position by the second lost motion spring. And since the second lost motion spring is weaker than the valve spring, there is no fear of opening the valve against the valve spring. In addition, since it is weaker than the first lost motion spring, there is no concern that the first lost motion spring will prevent the input arm from following the cam.

  According to the present invention, the working angle of the valve can be continuously changed by the working angle varying device, and the switching state can be switched between the connected state in which the valve is driven and the unconnected state in which the driving of the valve is suspended. In addition, even if the pin hole position of the input arm at the time of base circle contact is not fixed, the position of both pin holes at the time of non-connected base circle contact can be aligned by the arm position correction mechanism. There is no difficulty in displacement from the non-connected position to the connected position. Therefore, it is possible to stably switch from the unconnected state to the connected state.

It is a perspective view which shows the variable valve mechanism of an Example. It is a front view which shows the variable valve mechanism of an Example. It is a side view which shows the variable valve mechanism of an Example. It is a perspective view which shows the output arm of the variable valve mechanism of an Example. It is a fragmentary sectional view which shows when changing the variable valve mechanism of an Example from a connection state to a non-connection state in order to (a)-(c). It is a fragmentary sectional view which shows when changing the variable valve mechanism of an Example from a non-connection state to a connection state in order to (a)-(c). It is a side view which shows the variable valve mechanism of the example 1 of a change of an Example. It is a side view which shows the variable valve mechanism of a prior art example. (A) is a side view showing a variable valve mechanism of a reference example, (b) is a partial cross-sectional view showing a connected state of the variable valve mechanism of the reference example, and (c) is a non-connection of the variable valve mechanism of the reference example. It is a fragmentary sectional view showing a state.

  The variable valve mechanism 8 of the embodiment shown in FIGS. 1 to 6 is a mechanism for driving the valves 7 and 7 according to the rotation of the internal combustion engine, and includes the following valve springs 9 and 9, a cam 10, and the like. The input arm 20, the output arms 30, 30, the operating angle variable device 40, the switching device 50, and the arm position correction mechanism 60 are configured. Hereinafter, one of the input arms 20 and the output arms 30 and 30 in the width direction is referred to as “left”, and the other is referred to as “right”.

[Valve springs 9, 9]
The valve springs 9 are composed of a left valve spring 9 provided for the left valve 7 and a right valve spring 9 provided for the right valve 7. Each valve spring 9 is a spring for urging the valve 7 in the closing direction, and is attached between the cylinder head and the valve 7.

[Cam 10]
The cam 10 includes a base circle 11 having a true circular cross section provided on a cam shaft 19 that rotates in accordance with the rotation of the internal combustion engine, and a nose 12 protruding from the base circle 11.

[Input arm 20]
The input arm 20 is an arm that swings by being driven by the cam 10, and is pivotally supported by a rocker shaft 29 whose lengthwise intermediate portion extends in the left-right direction. The upper surface of the rear end portion is in contact with the lower end of the first lost motion spring 23 via the lost motion lifter 24. The first lost motion spring 23 is a spring for urging the input arm 20 to the cam 10 to cause the input arm 20 to follow the cam 10 in a connected state and a non-connected state. Further, pin holes 25 and 25 are recessed in both side surfaces of the rear portion of the input arm 20.

[Output arms 30, 30]
The output arms 30 are composed of a left output arm 30 provided on the left side of the input arm 20 and a right output arm 30 provided on the right side. When each output arm 30 is connected to the input arm 20, it swings together with the input arm 20 to drive the valve 7. Each output arm 30 is pivotally supported by the rocker shaft 29 at the middle in the length direction, and the lower surface of the front part is in contact with the valve 7 via the intervening arm 37. The rear end portion of the intervening arm 37 is supported by a lash adjuster 39 so as to be swingable, and a roller 38 that is in contact with the lower surface of the front portion of the output arm 30 is rotatably supported at an intermediate portion in the longitudinal direction. The lower surface is in contact with the valve 7.

  Further, a projection 34 is provided on the side surface opposite to the input arm 20 side of the tip of each output arm 30, and the output arm 30 is biased toward the valve 7 on the upper surface of the projection 34. One end of the two lost motion springs 33 abuts from above. The second lost motion spring 33 is a torsion coil spring. The coil-shaped intermediate portion in the longitudinal direction is externally fitted to the rocker shaft 29, and the other end is supported by a support portion (not shown). The second lost motion spring 33 is weaker than both the first lost motion spring 23 and the valve spring 9. Further, a pin hole 35 is recessed in the side surface on the input arm 20 side at the rear of each output arm 30. And this pin hole 35 is comprised so that it may align with the pin hole 25 of the input arm 20 at the time of nose contact | abutting in a non-connecting state (an axial line is located in a straight line).

[Working angle variable device 40]
The operating angle varying device 40 is interposed between the cam 10 and the input arm 20, and is displaced by displacing the position of the input arm 20 when the nose is in contact with the nose 12 in the swinging direction. The operating angle of the valve 7 is changed. The operating angle varying device 40 includes a rotating device (not shown) that rotates the rocker shaft 29 to both sides in the circumferential direction, and a first link 41 that is fixed to the rocker shaft 29 and rotates together with the rocker shaft 29. The upper end portion of the first link 41 is pivotally attached to the upper end portion of the first link 41, the input roller 43 abutting on the cam 10 is rotatably supported at the intermediate portion in the longitudinal direction, and the input arm 20 is supported at the lower end portion. An output roller 44 that abuts on the upper surface of the distal end portion of the head includes a second link 42 that is rotatably supported. Then, by rotating the rocker shaft 29 with a rotating device (not shown), the position of the input arm 20 at the time of nose contact is displaced in the swinging direction via the first link 41 and the second link 42. The operating angles of the valves 7 and 7 are continuously changed.

[Switching devices 50, 50]
The switching devices 50, 50 are a left switching device 50 provided across the input arm 20 and the left output arm 30, and a right switching device 50 provided across the input arm 20 and the right output arm. It consists of. Each switching device 50 is switched to a connected state in which the valve 7 is driven by connecting the input arm 20 and the output arm 30, and is switched to a non-connected state in which the driving of the valve 7 is stopped by releasing the connection. Each switching device 50 includes a pin 51 and a displacement device 52 described below.

  The pin 51 is between a connection position that spans between the pin hole 25 of the input arm 20 and the pin hole 35 of the output arm 30 and a non-connection position that is accommodated in the pin hole 25 of the input arm 20 without straddling. Displaceable. Specifically, the pin 51 includes a cylindrical outer pin 51a and an inner pin 51b provided inside the outer pin 51a. Then, after the side surface of the distal end portion of the outer pin 51a is hooked on the latching portion 62 of the arm position correction mechanism 60 in the unconnected state, the distal end portion of the inner pin 51b is advanced by the inner pin 51b extending from the inner side of the outer pin 51a. Enters the pin hole 35 of the output arm 30. As a result, the state is switched to a connected state. In the connected state, the input load from the cam 10 is transmitted to the second link 42, the input arm 20, the pin 51, and the output arm 30, and the valve 7 is driven via the interposition arm 37. Is done.

  The displacement device 52 is a device for displacing the pin 51 between a connected position and a non-connected position. The displacement device 52 includes a hydraulic chamber 53 in which the pin hole 35 of the output arm 30 is closed by a hydraulic pin 54, an oil passage 55 that supplies hydraulic pressure to the hydraulic chamber 53, and a bottom surface of the pin hole 25 of the input arm 20. And a first return spring 56 interposed between the outer pin 51a and a second return spring 57 interposed between the bottom surface of the outer pin 51a and the inner pin 51b.

[Arm position correction mechanism 60]
The arm position correction mechanism 60 is a mechanism for solving the following problems. That is, when the position of the input arm 20 at the time of nose contact is displaced in the swing direction by the operating angle varying device 40, the position of the input arm 20 at the time of contact of the base circle with which the base circle 11 contacts is also displaced in the swing direction. To do. Therefore, the position of the pin hole 25 of the input arm 20 at the time of base circle contact is not determined. Therefore, in the non-connected state, the positions of both pin holes 25 and 35 are not aligned when the base circle contacts. Therefore, the pins 25 and 35 are not easily displaced from the non-connection position to the connection position. This is because even if the positions of both pin holes 25 and 35 are aligned at the timing of the nose contact other than the base circle contact, the timing is instantaneous, so it is difficult for the pin 51 to be displaced in that instant. Because.

  The arm position correction mechanism 60 corrects the position of the output arm 30 from the predetermined rest position to the swinging direction of the input arm 20 during a period including the time of base circle contact before switching from the non-connected state to the connected state. This is a mechanism for aligning the positions of both pin holes 25 and 35. Specifically, the arm position correcting mechanism 60 is provided with a guide groove 61 that is recessed in the side surface of each output arm 30 on the input arm 20 side and extends in the swing direction from the front of the opening of the pin hole 35 of the output arm 30. It includes a latching portion 62 formed at the end portion of the groove 61 on the pin hole 35 side. Therefore, the latching portion 62 is provided on the swing direction side of the opening of the pin hole 35 of the output arm 30. When the latching portion 62 is in nose contact with the side surface of the distal end portion of the pin 51 projecting from the opening of the pin hole 25 of the input arm 20 to the opening of the pin hole 35 of the output arm 30 in the unconnected state. By hooking before the end of the step, the positions of the pin holes 25 and 35 are aligned so that the output arm 30 is displaced together with the input arm 20 during a period including the subsequent base circle contact.

  The manner in which the variable valve mechanism 8 shown above is switched between the connected state and the unconnected state will be described below.

[1] When switching from the connected state to the non-connected state When switching from the connected state shown in FIG. 5A to the non-connected state, as shown in FIG. 5B, the hydraulic pressure in the hydraulic chamber 53 increases (becomes ON). Thus, the inner pin 51b is pressed to the input arm 20 side by hydraulic pressure, whereby the tip of the inner pin 51b retreats from the pin hole 35 of the output arm 30 and retreats inside the outer pin 51a. As a result, the state is switched to the disconnected state, and the input arm 20 can swing relative to the output arm 30 (idle vibration). After that, as shown in FIG. 5 (c), the entire pin 51 is pressed against the input arm 20 by hydraulic pressure, so that the tip of the pin 51 is retracted from the guide groove 61 and the pin hole of the input arm 20. Retreat to 25. As a result, the pin 51 is not caught by the hook 62.

[2] When switching from the non-connected state to the connected state When switching from the non-connected state to the connected state shown in FIG. 5 (c), the hydraulic pressure in the hydraulic chamber 53 decreases (turns OFF) as shown in FIG. 6 (a). ), The pin 51 is displaced to the output arm 30 side by the restoring force of the first return spring 56, and the tip of the pin 51 protrudes from the pin hole 25 of the input arm 20 to the output arm 30 side and engages with the guide groove 61. Enter. Thereafter, as shown in FIG. 6B, the pin 51 is displaced along the guide groove 61, and the side surface of the distal end portion of the outer pin 51a is caught by the latching portion 62 before the end of the nose contact. As a result, the output arm 30 is displaced together with the input arm 20 in the swinging direction during a period including the subsequent base circle contact. During this time, the pin holes 25 and 35 are aligned (the axes are aligned in a straight line). At this time, as shown in FIG. 6C, the tip of the inner pin 51b advances from the inner side of the outer pin 51a and is output. It enters the pin hole 35 of the arm 30. As a result, the state is switched to the connected state, and the output arm 30 swings together with the input arm 20 to drive the valve 7.

According to the present embodiment, the following effects [A] to [D] can be obtained.
[A] In addition to being able to continuously increase and decrease the lift amount of the valves 7 and 7 with the working angle variable device 40, the switching device 50 switches between a connected state in which the valve is driven and a non-connected state in which the valve drive is stopped. You can also. Therefore, it leads to improvement in fuel consumption.

[B] Even if the position of the pin hole 25 of the input arm 20 at the time of base circle contact is not determined, both pin holes 25, Since the positions of the pins 35 can be aligned, the pin 51 can be displaced from the unconnected position to the connected position at any time during the period including the time when the base circle contacts. Therefore, the pin 51 is not easily displaced and can be stably switched from the non-connected state to the non-connected state. Further, since the arm position correction mechanism 60 includes the guide groove 61, the pin 51 can be guided to the latching portion 62 and the pin hole 35.

[C] Since the pin 51 is composed of an outer pin 51 a that abuts on the latching portion 62 and an inner pin 51 b that enters the pin hole 35 of the output arm 30, compared with a case where they are integrally configured. Thus, friction between the pin 51 and the latching portion 62 can be reduced. Therefore, the pin 51 can be smoothly displaced from the unconnected position to the connected position.

[D] Since the second lost motion springs 33 and 33 are provided, the output arms 30 and 30 can be quickly returned to a predetermined rest position. Since the second lost motion springs 33 and 33 are weaker than the valve springs 9 and 9, there is no fear of opening the valves 7 and 7 against the valve springs 9 and 9. Further, since it is weaker than the first lost motion spring 23, there is no concern that the first lost motion spring 23 will cause the input arm 20 to follow the cam 10 in the connected state.

In addition, this invention is not limited to the said Example, For example, like the following modification 1, it can also be changed and embodied suitably in the range which does not deviate from the meaning of invention.
[Modification 1] Instead of the second lost motion spring 33 of the embodiment, as shown in FIG. 7, a second lost motion spring 33 ′ that contacts the lower surface of the rear end portion of the output arm 30 from below may be provided. Good.

7 valve 8 valve spring 9 variable valve mechanism 10 cam 11 base circle 12 nose 20 input arm 23 first lost motion spring 25 input arm pin hole 30 output arm 33 second lost motion spring 35 output arm pin hole 40 working angle Variable device 50 Switching device 51 Pin 51a Outer pin 52b Inner pin 60 Arm position correction mechanism 61 Guide groove 62 Hook

Claims (5)

An input arm (20) that swings when driven by a cam (10);
An output arm (30) that drives the valve (7) by swinging with the input arm (20) when coupled to the input arm (20);
Connection for driving the valve (7) by displacing the pin (51) to a connection position straddling the pin holes (25, 35) of both the arms (20, 30) of the input arm (20) and the output arm (30). A switching device (50) for switching to a non-connected state in which the driving of the valve (7) is suspended by switching to a state and displacing the pin (51) to a non-connected position that does not straddle both pin holes (25, 35);
It is interposed between the cam (10) and the input arm (20), and the position of the input arm (20) at the time of nose contact with which the nose (12) of the cam (10) contacts is displaced in the swinging direction. A working angle varying device (40) for changing the working angle of the valve (7) in the connected state;
When the position of the input arm (20) at the time of nose contact is displaced in the swinging direction by the operating angle variable device (40), the input arm at the time of base circle contact that the base circle (11) of the cam (10) contacts. Since the position of (20) is also displaced in the swinging direction, the position of the pin hole (25) of the input arm (20) at the time of base circle contact is not fixed, so both pin holes (25, 35 are not connected). ) Are not aligned when the base circle is in contact, and the pin (25, 35) is not easily displaced from the unconnected position to the connected position. An internal combustion engine including an arm position correction mechanism (60) that aligns the positions of both pin holes (25, 35) when the base circle is in contact with each other by being displaced so as to align with the position of (20). Variable valve mechanism.   The arm position correcting mechanism (60) is provided on the one arm (30) on the swing direction side of the opening of the pin hole (35) of one arm (30) of the input arm (20) and the output arm (30). The front end of the pin (51) protruding from the pin hole (25) of the other arm (20) is hooked to the hook (62) in a disconnected state, including the hook (62) provided on the side surface. 2. The internal combustion engine according to claim 1, wherein the positions of both pin holes (25, 35) when the base circle is brought into contact with each other in a non-connected state are aligned so that the output arm (30) is displaced together with the input arm (20). Variable valve mechanism.   The arm position correction mechanism (60) includes a guide groove (61) that is recessed in the side surface of one arm (30) and extends in the swinging direction from the front of the opening of the pin hole (35) of the arm (30). The variable valve mechanism for an internal combustion engine according to claim 2, wherein the latching portion (62) is formed at an end portion of the guide groove (61).   The pin (51) includes a cylindrical outer pin (51a) and an inner pin (51b) provided inside the outer pin (51a), and the pin hole (25) of the other arm (20). After the tip of the outer pin (51a) protruding from the hook is hooked on the latch (62), the inner pin (51b) advances from the inside of the outer pin (51a), so that the tip of the inner pin (51b) The variable valve mechanism for an internal combustion engine according to claim 2 or 3, which enters the pin hole (35) of one arm (30).   A valve spring (9) for urging the valve (7) in the closing direction, a first lost motion spring (23) for urging the input arm (20) to the cam (10), and an output arm (30) for the valve ( The second lost motion spring (33) weaker than any of the valve spring (9) and the first lost motion spring (23), which is biased to 7), is provided according to any one of claims 1 to 4. Variable valve mechanism.

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