JP3313802B2 - Variable valve lift device for engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve lift device for an engine.

[0002]

2. Description of the Related Art In an engine such as an automobile, a lift amount or opening / closing timing (valve timing) of intake and exhaust valves is changed according to an operating state of the engine as described in, for example, Japanese Patent Application Laid-Open No. 63-106310. There is one that can be switched. This is because two types of cams, a low-speed cam and a high-speed cam, having different profiles are provided on the camshaft, and one end is swingably supported by a rocker arm shaft, and the other end corresponds to an intake valve or an exhaust valve. A low-speed rocker arm that is in contact with and contacts the low-speed cam at an intermediate portion; a high-speed rocker arm that is pivotally supported at one end on the rocker arm shaft and abuts the high-speed cam at an intermediate portion; Connecting means for connecting the rocker arms of the low and high speed rockers at the time of high-speed operation of the engine, so that the valve can be opened and closed according to the high-speed cam, At low speed rotation, the valve is opened and closed according to the low speed cam by separating the low speed rocker arm from the high speed one. It is possible, so that the valve lift amount to the valve timing of the best respectively with time during a high-speed operation low-speed operation of the engine is obtained.

[0003]

However, in the prior art described in the above-mentioned publication, the high-speed rocker arm or the low-speed rocker arm moves integrally during high-speed operation. Conversely, the inertial mass increases, and there is a problem that speeding up of the engine is hindered. In addition, since the low-speed cam and the high-speed cam having different profiles are switched, there is a problem that abnormal noise is generated at the time of the switching.

The present invention addresses the above-described problem in an engine in which a camshaft drives intake and exhaust valves via a rocker arm, and provides a valve lift without increasing an inertial mass of a valve train. The main object is to realize a device capable of changing the value.

[0005]

That is, a variable valve lift device for an engine according to the invention of claim 1 of the present application (hereinafter referred to as the first invention) drives a suction and exhaust valve via a rocker arm by a camshaft. Engine
To fraud and mitigating risk support position of the rocker arm for driving the air intake valve or exhaust valve in response to the cam profile of the first cam provided on the camshaft, the low speed rotation of the engine is low interest
Change to shift side, high-speed rotation is provided a supporting position changing means for changing the high-lift side, the supporting position changing means, Kamushi
The second cam provided on the shaft and the camshaft are separate
Is rockably mounted on the shaft of
A first swing arm having a support for the arm, and the shaft
And is connected to the second cam at one end side.
And the rocker arm supporting position
Lock means for holding the lift side,
Contact the other end of the arm with the support of the first swing arm.
Hydraulic clearance adjustment mechanism with a contacting plunger
The second cam has the cam nose of the first cam on the rocker arm.
In the area where the second swing arm faces when
The cam has a small diameter and the locking means is
Evacuated by return spring provided on the body side
Lock piston that moves forward and backward under hydraulic pressure
And the lock pin provided on the second swing arm
And the engagement hole
However, the base circle of the first cam acts on the rocker arm
The second rocking movement so as to correspond to the lock pin
It is characterized by being provided on the arm .

The variable valve lift device for an engine according to the invention of claim 2 of the present application (hereinafter, referred to as a second invention) sucks and discharges the camshaft through a rocker arm.
In the engine that drives the air valve, the intake valve is also
Or raise the rocker arm supporting the exhaust valve.
Corresponds to the cam shape of the first cam provided on the camshaft
When the engine is running at low speed, change to low
A support position changing means that changes to the high lift side during high-speed rotation is provided.
And the supporting position changing means is provided on the camshaft.
Having a second cam and a rocker arm support portion.
A first swing arm both in contact with the first cam, and a cam shaft
Is pivotally supported on a different shaft from the first
A second swing arm that rotatably supports the arm, and a rocker arm.
Locking means for holding the arm support position on the high lift side.
Having a connecting portion between the first swing arm and the second swing arm.
If the roller in contact with the second cam is rotatably supported
In both cases, the engine body comes into contact with the base end of the rocker arm.
The main body of the hydraulic clearance adjustment mechanism with a plunger
The second cam is provided on the first swing arm.
When the nose works, the area where the rollers face
The cam has a small diameter.
Provided on the gin body side and retracted by the return spring
Lock that moves forward and backward under hydraulic pressure while being urged in the evacuation direction
And a lock pin provided on the second swing arm.
And an engagement hole with which the
The mating hole is in the first swing arm and the base circle portion of the first cam.
The lock pin
It is characterized in that it is provided on two swing arms .

[0007]

[0008]

[0009]

[0010]

[0011]

[0012]

The invention of claim 3 of the present application (hereinafter referred to as the
According to a third aspect of the present invention, in the variable valve lift device for an engine, the second swing arm according to the first or second aspect of the invention is disposed so as to straddle between two adjacent valves arranged in the camshaft direction. In addition, a lock means is provided at the center of the second swing arm in the valve arrangement direction.

[0014]

First, according to the first and second aspects of the present invention, the support position of the rocker arm for driving the intake valve or the exhaust valve is set at a low lift position where the lift amount is small and a high position where the lift amount is large according to the operating state of the engine. Since the valve lift is changed to the lift position, the valve lift can be changed without increasing the inertial mass.

[0015] Then, while rotating mosquitoes Mushafuto and synchronization, the cam nose of the first cam acts on the rocker arm
The first rocking arm supporting the rocker arm comes into contact with the second cam having a small diameter in a region facing the second rocking arm via the second rocking arm. Therefore, when these rocking arms are not locked, the support position of the rocker arm is lowered, and the valve lift is reduced. Meanwhile, these rocking
When the arm is locked, the support position of the rocker arm is held on the high lift side, and the valve lift becomes relatively large. Thus, the valve lift can be changed with a simple configuration.

[0016] Particularly, it means that the support position of the rocker arm during high-speed rotation of the engine is changed to a high lift position, it is possible to increase the valve lift without increasing the inertial mass, the engine Can be improved.

In particular , since the second cam is provided on the camshaft, an extra shaft for supporting the second cam is not required, and the number of parts is reduced.

Also , the base support of the first cam is attached to the rocker arm.
When the vehicle part operates, the engagement hole provided in the second swing arm and the lock pin coincide with each other, so that the swing arm can be smoothly locked and released.

Meanwhile, the plunger of the hydraulic clearance adjustment mechanism provided in the second swing arm supported on the sheet Yafuto,
Since it comes into contact with the support portion of the rocker arm provided on the first swing arm supported on the shaft,
The rocker arm reliably comes into contact with the cam surface, so that good followability can be obtained. At the time of high-speed rotation, the rocker arm elastically contacts the locked second swing arm via the hydraulic gap adjusting mechanism. As a result, good support rigidity can be obtained.

Further, according to the second aspect of the invention, by providing the main body of the hydraulic clearance adjusting mechanism in the engine main body, the valve train can be reduced in weight, and the hydraulic supply system for operating the mechanism can be reduced. Is also simplified.

[0021] According to the first and second invention, Rokkaa
When the base circle of the first cam acts on the
Or the base circle part of the first cam is formed on the first swing arm.
When used, the engagement hole provided in the second swing arm coincides with the lock pin, so that the locking and releasing operation of the second swing arm is performed smoothly.

Further, according to the third aspect of the present invention, the second swing arm having the hydraulic clearance adjusting mechanism is arranged so as to straddle between two adjacent valves arranged in the camshaft direction. Since the locking means is provided at the center of the two swing arms in the valve arrangement direction, the loads acting on the two hydraulic clearance adjusting mechanisms provided on the second swing arm corresponding to both valves are substantially balanced. As a result, it acts on the lock means, and unreasonable deformation is prevented.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, a combustion chamber 3 is formed in a cylinder head 2 of the engine 1 by recessing a bottom surface of a central portion thereof. The cylinder head 2 is provided with an intake port 4 communicating from one side to the combustion chamber 3 and an exhaust port 5 communicating from the other side to the combustion chamber 3. , 5 are provided with intake and exhaust valves 6, 7 for opening and closing the openings to the combustion chamber ceiling surface. The intake valve 6 is shown in FIG.
As shown in the figure, three are provided for each cylinder along the cylinder row direction. Although not shown, two exhaust valves 7 are provided for each cylinder along the cylinder row direction.

[0025] Then, as shown in FIG. 1, the intake valve 6 ₁ arranged at the center of the cylinder row direction is a valve shaft 6b extending upward is provided continuously to the valve body 6a, the valve The shaft 6b penetrates the cylinder head 2 almost vertically, and a spring retainer 8 is provided at the upper end thereof. A valve spring 9 is interposed between the retainer 8 and the upper surface of the cylinder head. .

[0026] Incidentally, the intake valves 62 and 63 arranged on both sides of the intake valve 61, the valve shaft 6 b, 6 b are disposed so as to penetrate the cylinder head 2 at the upper left side.

The exhaust valve 7 disposed on the opposite side of the combustion chamber 3 is provided with an upwardly extending valve shaft 7b connected to the valve body 7a, and the valve shaft 7b is connected to the cylinder head. 2
, And a spring retainer 8 is provided at the upper end thereof, and a valve spring 9 is interposed between the retainer 8 and the upper surface of the cylinder head.

On the other hand, on the upper side of the cylinder head 2, first and second camshafts 10 and 11 are distributed and arranged corresponding to the intake and exhaust valves 6 and 7. The exhaust cam 12 provided on the second camshaft 11 disposed above the exhaust valve 7 has a plunger 13 a of a base end side of an HLA (hydraulic lash adjuster) 13.
Rocker arm 14 pivotally supported by the pump
A roller 15 rotatably supported at an intermediate portion of the exhaust valve 7 abuts, and a distal end portion of the exhaust rocker arm 14 is disposed in contact with a valve shaft head of the exhaust valve 7.

As shown in FIG. 2, on the valve shaft heads of the _two intake valves 6 ₁ and 62 arranged at the center and on the other side thereof, as support position changing means according to the first embodiment. The base end portions 17a, 18a
The tip portions 17b, 18b of the first and second intake rocker arms 17, 18 which are supported so as to be movable up and down are arranged in contact with each other, and pins 19, 19 are provided at intermediate portions between the rocker arms 17, 18. Rollers 20, 20 rotatably supported via contact with the lower surfaces of first and second intake cams 21, 22 as first cams provided on the first camshaft 10.

[0030] Note that the valve stem heads of the front side of the intake valve 6 _3, the distal end 23b of the third intake rocker arm 23 having a base end portion 23a is pivot supported by HLA24 is arranged Taise', A roller 25 supported by an intermediate portion of the rocker arm 23 is in contact with a lower surface of a third intake cam 26 provided on the first camshaft 10.

Here, the variable valve lift mechanism 16 will be described. As shown in FIGS. 2 to 6, the first camshaft 10 is located between the first and second intake cams 21 and 22. An operation cam 27 constituting two cams is provided. The operation cam 27 includes first and second intake cams 21,
With a phase difference of approximately 90 degrees clockwise with respect to 22, concentric arc portions 27 corresponding to the base circle portions 21 a, 22 a of the first and second intake cams 21, 22.
a and the cam nose 21b, 2 of the intake cam 21, 22
A small-diameter portion 27b whose area corresponding to 2b has a small diameter is formed.

On the other hand, a hollow shaft 29 provided with an oil gallery 28 therein is disposed in a parallel state below the first camshaft 10 on the side of the cylinder head. Two first swing arms 30, 30, which support the first and second intake rocker arms 17, 18 at positions corresponding to the first and second intake cams 21, 22, respectively, are pivotally supported pivotally. And the operating cam 2 is located between the first swing arms 30, 30.
The second swing arm 31 is pivotally supported at a position corresponding to 7.

The second swing arm 31 is provided with two support pieces 31a and 31b.
A roller 33 rotatably supported between a and 31b via a pin 32 is configured to roll on the outer peripheral surface of the operation cam 27. Below the second swing arm 31, extension portions 31c and 31d projecting to both sides are provided, and these extension portions 31c and 31d are respectively provided with HLAs 34 and 34 constituting a hydraulic clearance adjusting mechanism. Built-in.

Here, the roller 33 provided on the second swing arm 31 and the first and second intake rocker arms 1
For example, as shown in FIG. 4, when the rollers 20 of the first intake rocker arm 17 are in contact with the base circle portion 21a of the first intake cam 21 as shown in FIG. The second swing arm 3 is attached to the arc portion 27a of the operation cam 27 corresponding to the base circle portion 21a.
One roller 33 is set so as to abut.

On the other hand, each of the first swing arms 30, 30 has a base end 1 of the first and second intake rocker arms 17, 18, respectively.
7a, 18a are swingably supported via pins 35, 35, and a receiving portion 30a provided at the distal end of the first swing arms 30, 30 projects from the HLAs 34, 34 so as to be able to advance and retreat. Plungers 34a, 34a are arranged in contact with each other. The hydraulic oil is supplied to an oil chamber 34b formed at the back of the HLA 34 via an oil passage 36 provided between the hollow shaft 29 and the oil gallery 28. Thus, the oil gallery 28 can be used as an oil sump.

As shown in FIG. 5, a support base 3 is provided on the cylinder head 2 at a position substantially corresponding to the center of the intake valves 6 ₁ and 6 _2.
7 is protruded, a cylinder 38 is bored in the support base 37, and a lock pin 39 constituting a lock means for the cylinder 38 is able to move forward and backward through a plug 40 attached to the cylinder 38. Is interpolated. An operating oil pressure is supplied / discharged via a hydraulic passage 42 to a hydraulic chamber 41 formed at the back of a pressure receiving portion 39 a connected to the bottom of the lock pin 39. A return spring 43 is provided between the pressure receiving portion 39a and the plug 40. On the other hand, the second swing arm 3
1 has an engagement hole 44 with which the lock pin 39 is engaged.
The roller 33 provided on the swing arm 31 is used for the operation cam 2.
7 is provided so as to correspond to the lock pin 39 when in contact with the arcuate portion 27 a provided on the lock 7.

As shown in FIG. 7, an electromagnetic three-way valve 46 is interposed between a hydraulic supply source 45 and a hydraulic passage 42 leading to a hydraulic chamber 41 for operating the lock pin 39. In the OFF state, the electromagnetic three-way valve 46 connects the hydraulic chamber 41 to the drain passage 47 and
The hydraulic oil supplied by the hydraulic pressure supply source 45 during the N operation is supplied to the hydraulic chamber 41.

Further, the engine 1 has the electromagnetic three-way valve 4
Control unit 48 for ON / OFF operation of 6
Is provided, the control unit 48 inputs the signal from the rotation sensor 49 for detecting an engine speed, when the engine speed N _E as shown in FIG. 8 is greater than the predetermined switching revolution speed N ₀ The electromagnetic three-way valve 46 is turned on.

According to the above configuration, the engine speed N _E
Is smaller than the switching speed N ₀ , the lock pin 39 is in the retracted state, and the second swing arm 31 is in the free state. Therefore, as shown in FIG. 9, when the first intake rocker arm 17 is pushed down by the cam nose 21 b of the first intake cam 21, for example, the roller 33 at the upper end of the second swing arm 31 is moved to the small diameter portion 27 of the operation cam 27.
b. Therefore, the second swing arm 31 rotates clockwise around the hollow shaft 29, and accordingly, the first swing arm 30 also rotates clockwise around the hollow shaft 29. As a result, the fulcrum position of the first intake rocker arm 17 decreases. Thus, pressing of the intake valves 6 ₁ of the first intake rocker arm 17 is reduced, FIG. 1
As shown by the solid line of 0, the valve lift becomes small.

On the other hand, the engine speed N _E is switching rotational speed N ₀
When it is larger than the hydraulic chamber 4 through the hydraulic passage 42,
1 is supplied with hydraulic oil. Therefore, the lock pin 39 projects as shown by the chain line in FIG.
The second swing arm 31 engages with the engagement hole 44 formed in the second swing arm 31.
Will be locked. At this time, the engagement hole 44 formed in the second swing arm 31 as described above makes the roller 33 provided in the swing arm 31 abut against the arc portion 27 a provided in the operation cam 27. Is provided so as to correspond to the lock pin 39 when
The locking operation of the second swing arm 31 is smoothly performed.

In the state where the second swing arm 31 is locked as described above, when the first intake rocker arm 17 is pushed down by the cam nose 22b of the first intake cam 21, as shown in FIG. 2 swing arm 31
The roller 33 at the tip does not contact the small diameter portion 27b of the operation cam 27, whereby the HLA 34 provided on the second swing arm 31 is held at a high position, and the plunger 34a provided on the HLA 34 The rotation of the first swing arm 30 in the clockwise direction is regulated by the contact of the stopper 30a of the first swing arm 30. As a result, the fulcrum position of the first intake rocker arm 17 supported by the first swing arm 30 is maintained higher than at the time of low-speed rotation, and the amount of depression of the intake valve 61 by the first intake rocker arm 17 is large. Fig. 10
Valve lift as shown by a chain line is relatively larger than the low speed rotation of the.

Furthermore, at the time of high-speed rotation, the first intake rocker arm 17 is elastically supported by the locked second swing arm 31 via the plunger 34a of the HLA 34, so that good support rigidity can be obtained. Will be.

Of course, the second intake rocker arm 18 also performs the same movement as described above, so that the fulcrum position decreases during low-speed rotation to reduce the valve lift, and the fulcrum position increases during high-speed rotation. To increase the valve lift relatively.

The exhaust rocker arm 14 may be provided with a variable valve lift mechanism.

Next, referring to FIG. 12 to FIG.
The variable valve lift mechanism 50 according to the embodiment will be described.

As shown in FIG. 12, also in the second embodiment, the first and second intake cams 5 are provided on the camshaft 51.
Actuating cam 5 which is located between 2 and 53 and constitutes the second cam
4 are provided. The operating cam 54 has approximately 60 clockwise directions with respect to the first and second intake cams 52 and 53.
The first and second intake cams 52,
A concentric arc portion 54a corresponding to the base circle portions 52a, 53a of 53 and a small diameter portion 5 in which the area corresponding to the cam nose 52b, 53b of the cams 52, 53 has a small diameter.
4b are formed.

On the other hand, a hollow shaft 56 provided with an oil gallery 55 therein is disposed in parallel at a position below the camshaft 51 on the side of the cylinder head. The second swing arm 57 in the embodiment is pivotally supported so as to freely swing. Here, the second swing arm 57 and the first intake rocker arms 58 and 59 disposed on the side are firstly supported.
The swing arm 60 is rotatably connected to each other via a pin 61. The roller 62 disposed between the support pieces provided on the first swing arm 60 is
And is rotatably supported via the. The roller 62 rolls on the outer peripheral surface of the operation cam 54.

On the other hand, the first rocking arm 60 supports rocker arms 58 and 59 via its intermediate portion so as to be rockable, and the rocker arms 58 and 5.
A plunger 63a protruding from the HLA 63 so as to be able to move forward and backward is disposed at the base end of the pipe 9 in contact with the HLA 63. In this embodiment, the HLA 63 is built in the cylinder head 64.

The lock of the second swing arm 57 is turned ON and OF
The mechanism for performing F is the same as in the first embodiment.

[0050] Thus, when the engine rotational speed N _E is less than the changeover rotational speed N _O, as in the first embodiment, the second Yuradoa locking pin 65 is in the retracted state - arm 57 is pretending - state Becomes

Accordingly, as shown in FIG. 14, for example, when the first oscillating arm 60 is pushed down by the cam nose 52b of the first intake cam 52, it is disposed between the support pieces of the first oscillating arm 60. Roller 62 is actuated by cam 54
It will come into contact with the small diameter portion of b. Accordingly, the second swing arm 57 rotates counterclockwise about the hollow shaft 56 as an axis, and accordingly, the first swing arm 60 rotates clockwise. The support position of the first intake rocker arm 58 is held higher than when the operating cam 54 is locked.
As a result, the amount by which the first intake rocker arm 58 pushes down the intake valve 66 ₁ is reduced, and the valve lift is reduced.

Meanwhile, the engine speed N _E is switching rotational speed N _O
When it is larger than the above, the second swing arm lock mechanism described above operates.

In this state, as shown in FIG.
When the first oscillating arm 60 is pushed down by the cam nose 52 b of the intake cam 52, the roller 62 disposed between the first oscillating arm support pieces causes the small-diameter portion 54 of the operating cam 54.
b, and the position of the pin 61 connecting the first and second swing arms is also kept low. Therefore, the first
The support position of the intake rocker arm 58 is maintained lower than at the time of low-speed rotation, and the first intake rocker arm 5
8 increases the amount of depression of the intake valve 66 ₁ by the amount of valve lift becomes relatively larger than the low speed rotation.

Of course, the second intake rocker arm 59 also operates in the same manner as described above. At low speed rotation, the support position rises to reduce the valve lift, and at high speed rotation, the support position decreases. To increase the valve lift relatively.

The exhaust rocker arm may be provided with a variable valve lift mechanism 50.

[0056]

First, according to the first and second aspects of the present invention, the support position of the rocker arm for driving the intake valve or the exhaust valve is set at a low lift position where the lift amount is small and a high position where the lift amount is large according to the operating state of the engine. Since the valve lift is changed to the lift position, the valve lift can be changed without increasing the inertial mass. Moreover, since the rocker arm always comes into contact with the valve opening / closing cam, no noise is generated when changing the valve lift.

[0057] Then, while rotating mosquitoes Mushafuto and synchronization, the cam nose of the first cam acts on the rocker arm
The first rocking arm supporting the rocker arm comes into contact with the second cam having a small diameter in a region facing the second rocking arm via the second rocking arm. Therefore, when these rocking arms are not locked, the support position of the rocker arm is lowered, and the valve lift is reduced. Meanwhile, these rocking
When the arm is locked, the support position of the rocker arm is held on the high lift side, and the valve lift becomes relatively large. Thus, the valve lift can be changed with a simple configuration.

[0058] Particularly, it means that the support position of the rocker arm during high-speed rotation of the engine is changed to a high lift position, it is possible to increase the valve lift without increasing the inertial mass, the engine Can be improved.

In particular , since the second cam is provided on the camshaft, an extra shaft for supporting the second cam is not required, and the number of parts is reduced.

Also , the base support of the first cam is attached to the rocker arm.
When the vehicle part operates, the engagement hole provided in the second swing arm and the lock pin coincide with each other, so that the swing arm can be smoothly locked and released.

[0061] On the other hand, the plunger of the hydraulic clearance adjustment mechanism provided in the second swing arm supported on the sheet Yafuto,
It means that contacts the support portion of the rocker arm provided in the first swing arm supported on said shaft,
The rocker arm reliably comes into contact with the cam surface, so that good followability can be obtained. At the time of high-speed rotation, the rocker arm elastically contacts the locked second swing arm via the hydraulic gap adjusting mechanism. As a result, good support rigidity can be obtained.

Further, according to the second aspect of the present invention, since the HLA constituting the hydraulic gap adjusting mechanism is provided on the engine body side, the valve operating mechanism can be reduced in weight, and the hydraulic supply system for operating the HLA can be provided. Simplified.

Further, according to the first and second invention, Rokkaa
When the base circle of the first cam acts on the
Or the base circle part of the first cam is formed on the first swing arm.
When used, the engagement hole provided in the second swing arm coincides with the lock pin, so that the locking and releasing operation of the second swing arm is performed smoothly.

Further, according to the third aspect of the present invention, the second swing arm having the hydraulic clearance adjusting mechanism is arranged so as to straddle between two adjacent valves arranged in the camshaft direction. Since the locking means is provided at the center of the two swing arms in the valve arrangement direction, the loads acting on the two hydraulic clearance adjusting mechanisms provided on the second swing arm corresponding to both valves are substantially balanced. As a result, it acts on the lock means, and unreasonable deformation is prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of an upper part of an engine.

FIG. 2 is a partial plan view of the engine.

FIG. 3 is an arrow view showing a variable valve lift mechanism and a structure around the variable valve lift mechanism as viewed from a direction of line AA in FIG. 2;

FIG. 4 is a cross-sectional view of a main part taken along line BB of FIG. 2;

FIG. 5 is a cross-sectional view of a main part taken along line CC of FIG. 2;

FIG. 6 is a cross-sectional view of a main part taken along line DD in FIG. 2;

FIG. 7 is a system configuration diagram showing a control system of a lock pin.

FIG. 8 is an operation characteristic diagram of the three-way solenoid valve with respect to the engine speed.

FIG. 9 shows a variable valve lift mechanism 1 during low-speed operation.
It is a schematic diagram which shows operation | movement of No.6.

FIG. 10 is a characteristic diagram showing a valve lift curve.

FIG. 11 is a schematic diagram showing the operation of the variable valve lift mechanism during high-speed operation.

FIG. 12 is a plan view of a main part of a variable valve lift mechanism of an engine according to a second embodiment.

FIG. 13 is a side view of a main part of the variable valve lift mechanism.

FIG. 14 is a schematic view showing the operation of the variable valve lift mechanism of the engine according to the second embodiment at the time of low-speed operation.

FIG. 15 is a schematic diagram showing the operation of the variable valve lift mechanism during high-speed operation.

[Explanation of symbols]

Reference Signs List 1 engine 10 first camshaft 21 first intake cam 21a base circle portion 21b cam nose 22 second intake cam 22a base circle portion 22b cam nose 6 ₁ intake valve 6 ₂ intake valve 17 first intake rocker arm 18 second intake rocker arm 27 Actuating cam 27a Arc portion 27b Small diameter portion 30 First swing arm 31 Second swing arm 34 HLA 34a Plunger 39 Lock pin 44 Engagement hole

Claims (3)

(57) [Claims] 1. A variable valve lift device for an engine, wherein a camshaft drives a suction valve and an exhaust valve via a rocker arm, wherein the position of the rocker arm for driving an intake valve or an exhaust valve is set to the camshaft. in response to the cam profile of the first cam provided on, during low speed rotation of the engine is variable in the low-lift side
Further, a support position changing means for changing to a high lift side at the time of high-speed rotation is provided , and the support position change means swings on a second cam provided on the camshaft and a shaft different from the camshaft. Movably supported
Swing arm having a rocker arm support portion
And a second cam supported swingably on the shaft.
A second swing arm that contacts one end of the rocker arm, and a lock that holds the support position of the rocker arm on the high lift side.
And the other end of the second swing arm has the first swing arm.
Hydraulic clearance adjustment with plunger abutting on support side
Mechanism is provided, the second cam nose of the first cam to the rocker arm is created
Small diameter in the area where the second swing arm faces when using
The locking means is provided on the engine body side and the return
Reduce the hydraulic pressure while being urged in the evacuation direction by the pulling.
A lock pin for receiving and moving back and forth, and
And an engagement hole with which the lock pin is engaged.
And the above-mentioned engagement hole is provided with the first cam of the rocker arm.
Corresponds to the above lock pin when the base circle part works
A variable valve lift device for an engine, wherein the variable valve lift device is provided on a second swing arm so as to be positioned . 2. A camshaft through a rocker arm.
Variable valve of the engine that drives the intake and exhaust valves
A lift device for supporting a rocker arm that drives an intake valve or an exhaust valve
Cammed first cam position provided in the Kamushafu DOO
To the low lift side when the engine is running at low speed.
Change the support position to change to the high lift side during high-speed rotation
Means for changing the support position , the support position changing means having a second cam provided on the camshaft and a support portion for the rocker arm and contacting the first cam.
A first swing arm and a camshaft pivotally supported on a different shaft.
Second swing arm that rotatably supports the first swing arm
And the locker that supports the rocker arm on the high lift side.
Means for connecting the first swing arm and the second swing arm to each other.
The rollers in contact with the system are rotatably supported,
The engine body has a protuberance that abuts the base end of the rocker arm.
The main body of the hydraulic clearance adjustment mechanism with a lancer is provided.
Is, the second cam, the cam nose of the first cam to the first swing arm
When acting, the roller has a small diameter in the area facing the roller.
A cam profile that is, locking means, provided on the engine body side Ritansu
Reduce the hydraulic pressure while being urged in the evacuation direction by the pulling.
A lock pin for receiving and moving back and forth, and
And an engagement hole with which the lock pin is engaged.
And the engaging hole is provided in the first swing arm with the first cam.
When the base circle part of
Variable valve lift device characteristics and to Rue engine that is provided in the second swing arm to respond position. 3. A second oscillating arm is disposed so as to straddle between two adjacent valves arranged in the camshaft direction, and is locked at a central portion of the second oscillating arm in the valve arranging direction. A means is provided.
3. The variable valve lift device for an engine according to claim 1 .