JP3268850B2 - Engine valve drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a valve (intake valve or intake valve).
The low-speed cam and the high-speed cam are integrally formed on the camshaft that drives the exhaust valve. The low-speed cam drives the valve at low-speed valve timing, while the high-speed cam drives the valve at high-speed. The present invention relates to a valve drive device for an engine that is driven at a timing.

[0002]

2. Description of the Related Art Conventionally, as a valve driving device for an engine of the above-described example, there are devices described in U.S. Pat. No. 4,203,397 and JP-A-3-151510. That is, the apparatus described in the former U.S. Pat. No. 4,203,397 has a low-speed arm 102 driven by a low-speed cam 101 as shown in FIGS. A high-speed arm 104 is disposed in the hollow portion of the rectangular frame-shaped arm via a pin 103, and the high-speed arm 104 is driven by a high-speed cam 105. .

A pivot 106 as a swing fulcrum is integrally formed at one end (the right end in the drawing) of the low-speed arm 102, and the pivot 106 is supported by a hydraulic lash adjuster, so-called HLA 107.
Latch means 110 driven around a support shaft 109 by an actuator 108 is provided.

Further, a spring retainer 111 integrally formed on the lower surface of the above-described high-speed arm 104 and a spring retainer 112 provided below the low-speed arm 102 are provided.
While the spring 113 is stretched, the upper end of the valve stem 116 of the valve 115 is pressed against the slipper-like valve contact portion 114 at the other end (left end in the drawing) of the low-speed arm 102 described above. .

According to this conventional device, as shown in FIG.
When the lock between the high-speed arm 104 and the high-speed arm 104 is released, the high-speed arm 104 swings freely with the pin 103 as a fulcrum, and the low-speed arm 102 swings with the low-speed cam 101. The valve timing at a low speed when the valve 115 is driven by the use cam 101 can be obtained.

On the other hand, when the latch means 110 is locked to the high-speed arm 104 by the actuator 108 as shown in FIG. 12, the high-speed arm 104 and the low-speed arm 102 are integrally formed with the pivot 106 as a swing fulcrum. Since the swing is performed by the high-speed cam 105, the valve timing at a high speed in which the valve 115 is driven by the high-speed cam 105 can be obtained as a result.

However, in this conventional apparatus, the low-speed arm 102 is formed in a substantially rectangular frame shape, and the high-speed arm 104 is disposed in the hollow portion of the rectangular frame-shaped arm. Since it is necessary to provide the arms 102 and 104 with the latch means 110 for changing to the free state and the restrained state and the spring 113 for returning the high-speed arm 104, the shapes of the arms 102 and 104 become substantially large, As a result, the entire valve driving device becomes large, and the weight is increased by the latch means 110, so that there is a problem that commercialization is difficult.

On the other hand, as shown in FIG. 13 and FIG. 14, the latter device described in Japanese Patent Application Laid-Open No. 3-151510 has a camshaft 200 with a low-speed cam 2 having a small cam profile.
01 and a high-speed cam 202 having a large cam profile are integrally formed, and a low-speed rocker arm 204 that swings around a rocker shaft 203 is provided at a position corresponding to the low-speed cam 201. A roller follower 205 that contacts the above-described low-speed cam 201 is provided in a concave groove formed in an intermediate portion of the rocker arm 204.

On both sides of the low-speed rocker arm 204, a pivot receiver 20 is provided at one end (the right end in the drawing).
6 is provided with high-speed rocker arms 208 and 208 (only one is shown in the drawing) having an HLA 207 at the other end (left end in the drawing), and the plunger 20 of the HLA 207 at the other end of the high-speed rocker arm 208 is provided.
9 is pressed against the upper end of the valve stem 211 of the valve 210, and the engagement concave portion having a semicircular cross section at the upper end on the other end side of the high-speed rocker arm 208 is configured to be able to engage with the pin 212 protruding from the low-speed rocker arm 204. On the other hand, the pivot receiver 206 at one end of the high-speed rocker arm 208 is connected to the pivot 2 at the upper end of the plunger 214 in the actuator 213.
A slipper 216 that is swingably attached to the high-speed cam 15 and that is integrally formed on the upper surface of the high-speed rocker arm 208 corresponds to the high-speed cam 202 described above.

According to this conventional apparatus, as shown in FIG. 13, when the hydraulic pressure of the actuator 213 is drained, the plunger 214 and the pivot 215 are moved downward, and the pivot receiver 206 of the high-speed rocker arm 208 is in the low position. The slipper 216 of the high-speed rocker arm 208 is separated from the high-speed cam 202 by allowing the rocker arm 208 to slant so that the movement of the low-speed cam 201 is controlled by the elements 205, 204, 212, and 20.
The valve timing at a low speed transmitted to the valve 210 via 7, 209 can be obtained.

On the other hand, when hydraulic pressure is supplied to the actuator 213 as shown in FIG. 14, the plunger 214 and the pivot 215 are moved upward, and the pivot receiver 206 of the high-speed rocker arm 208 is moved upward, so that
8 is displaced substantially horizontally, so that the high-speed rocker arm 2
08 slipper 216 is brought into contact with the high-speed cam 202,
The movement of the high-speed cam 202 is determined by the elements 216, 208, and 20.
The valve timing at the high speed transmitted to the valve 210 via 7, 209 can be obtained.

However, in this conventional device, the engaging recess having a semicircular cross section at the upper end of the other end of the high-speed rocker arm 208 and the pin 2 protruding from the low-speed rocker arm 204 are provided.
12 are engageable with each other, but the low-speed rocker arm 204 and the high-speed rocker arms 2 on both sides thereof.
There is no member for pivotally supporting the rocker arm 08 and the rocker arms 204 and 208 individually, and the rocker arms 204 and 208 are separately supported.
8 has a problem that it is difficult to secure a sufficient supporting rigidity.

[0013]

The invention according to claim 1 of the present invention not only reduces the sliding resistance at low speed but also includes two low speed rocker arms and one low speed roller follower. Each arm (two low-speed rocker arms and one high-speed swing arm) is swingably and integrally pivotally supported by one common high-speed swing arm .
It is possible to improve the supporting rigidity of the swingarm reference)
And one high-speed swing for two valves
Share both arm and one low speed roller follower
By doing so, the valve drive device in the cylinder row direction of the engine
Dimensions are further reduced and the two valves
It is an object of the present invention to provide an engine valve drive device capable of obtaining a uniform load input .

[0014]

The invention of claim 1, wherein of this invention SUMMARY OF] is a valve driving device for an engine which is integrally formed a low-speed cam and the high speed cam on a camshaft for driving the valve, Two low-speed rocker arms abutting on the upper ends of the valve stems of the two valves, a low-speed roller follower that is in rolling contact with the low-speed cam, and a high-speed swingably mounted on the engine so as to be in contact with and separate from the high-speed cam. The high-speed swing arm is configured to be vertically movable while the three members are arranged side by side in the longitudinal direction of the engine, and the three members are pivotally supported by a common single pin.
Single high-speed swing door between low-speed rocker arms
And a single roller follower for low speed
The high-speed cam separates from the high-speed swing arm and
When the speed cam and the low speed roller follower contact each other,
Single low speed roller follower with single pin and low speed
Drive two valves simultaneously via the rocker arm for
While the high-speed cam is
Contact with the single high-speed swing arm
Two pins via the single pin and the low-speed rocker arm.
The valve drive device of the engine is configured to simultaneously drive the valves .

[0015]

According to the first aspect of the present invention, when the high-speed swing arm is at the swinging position separated from the high-speed cam, the low-speed cam moves with the low-speed roller follower and the low-speed roller follower. The valve timing at the low speed transmitted to the valve via the rocker arm for high speed can be obtained. On the other hand, when the swing arm for high speed is in the swinging position in contact with the cam for high speed, the high speed cam moves at high speed. Valve timing at high speed transmitted to the valve via the swing arm for low speed and the rocker arm for low speed can be obtained.

Further, since the low speed roller follower described above at the time of low speed is rolling contact with the low-speed cam, of course it can be reduced in sliding resistance of the low speed, for the two low-speed Since the rocker arm, one low-speed roller follower, and one high-speed swing arm were swingably and integrally supported by a common single pin,
Combined with the load from the cam side and the load from the valve side being dispersed through the single pin, the support rigidity of each arm, that is, two low-speed rocker arms and one high-speed swing arm, is provided. There is an effect that can be improved .

In addition , a single high-speed swing arm and a single low-speed roller follower are disposed between the two low-speed rocker arms, and the high-speed swing arm and the low-speed roller follower are provided for the two valves. And a structure in which both are shared, so that the size of the valve drive device in the cylinder row direction of the engine can be further reduced, and the load input to the two valves can be set substantially uniformly. is there.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The drawings show a valve driving device for an engine. In FIGS. 1, 2 and 3, a cylinder head 3 is mounted on a cylinder block 2 having a cylinder bore 1 and three cylinder heads 3 which communicate with a combustion chamber 4 as appropriate are provided. Intake ports 5, 6, 7 and two exhaust ports 8, 9 are formed.

An intake valve 10 for opening and closing the intake port 5 and an intake valve 11 for opening and closing the intake port 6
And an intake valve 12 for opening and closing the above-described intake port 7 and exhaust valves 13 and 13 for opening and closing each of the above-mentioned exhaust ports 8, 9 to form a five-valve configuration of three intake valves and two exhaust valves. ing.

Each of these valves 10 to 13 is provided in a valve guide 14 provided in the cylinder head 3 in a valve stem 1.
5 and a split collet 16 at the upper end of the valve stem 15.
, And a valve spring 19 is stretched between a lower spring retainer 18 disposed at a predetermined portion of the cylinder head 3 and the above-described upper spring retainer 17. .

On the other hand, an intake camshaft 20 and an exhaust camshaft 21 extending in the cylinder row direction are provided, and the above-described intake camshaft 20 is provided with a plurality of camshaft bearings 22, 23.
And the exhaust camshaft 21 is supported by a plurality of camshaft bearings 24 and 25. The illustration of the bearing cap attached to the upper part of each of the above-described camshaft bearings 22 to 25 is omitted.

The above-described intake camshaft 20 has a low-speed cam 26 and a high-speed cam 27 corresponding to the two intake valves 10 and 11, and a low-speed cam 28 and a high-speed cam 28 corresponding to the remaining one intake valve 12. A cam 29 is formed, and the two intake valves 10, 11 are simultaneously driven by the above-mentioned cams 26, 27 via the first valve variable mechanism 30, and the second valve variable mechanism is made by the above-mentioned respective cams 28, 29. It is configured to drive the remaining one intake valve 12 via 31.
On the exhaust side, a third valve variable mechanism 32 (see FIG. 1) having the same configuration as the first valve variable mechanism 30 is disposed between the upper portions of the two exhaust valves 13, 13 so that the third valve variable mechanism 32 is arranged. The mechanism 32 is configured to simultaneously drive the two exhaust valves 13 on the exhaust side.

The specific configuration of the first variable valve mechanism 30 will be described in detail below with reference to FIGS. 4, 5, 6, and 7. The first variable valve mechanism 30 is provided with a rocker shaft 33 as a swing axis parallel to the intake camshaft 20 below the intake camshaft 20, and the rocker shaft 33 has a swing support end (left end in the drawing). A swing arm 34 for high speed is pivotally supported so that the swing arm 34 for high speed extends from the swing support end on the rocker shaft 33 side to the free end on the upper end side of the valve stem 15. A concave portion 35 for disposing a roller follower is formed on the free end side of the high-speed swing arm 34, and a tappet 36 is integrally formed on the free end.

A low-speed roller follower 38 which is in contact with the low-speed cam 26 is mounted in the roller follower recess 35 by using a single pin 37, and a high-speed swing is utilized by using the pin 37. On both sides of the arm 34, low-speed rocker arms 39 and 40 are mounted.

In other words, two low-speed rocker arms 3
A single high-speed swing arm 34 and a single low-speed roller follower 38 are provided between the high-speed swing arm 34 and the single low-speed roller follower 38. The intake valves 10 and 11 are configured to be simultaneously driven, and the four parts 3
4, 38, 39, and 40 are pivotally supported.

Here, the low-speed roller follower 38 described above is used.
2 and 4, the tappet 36 is located immediately below the high-speed cam 37, as shown in FIGS. An arc-shaped pivot portion 39 at the other end (left end in the drawing) of each of the low-speed rocker arms 39 and 40.
a, 40a are in contact with the upper surface of the plunger 42 of the hydraulic shock adjuster 41 (hereinafter simply abbreviated as HLA) attached to the cylinder head 3 and at one end (right end in the drawing) of each of the low-speed rocker arms 39, 40. The slipper-shaped valve contact portions 39b and 40b contact the upper ends of the valve stems 15 of the intake valves 10 and 11, respectively.

The above-mentioned low-speed rocker arms 39, 40
The low-speed rocker arms 39 and 40 are set to be shorter than the high-speed swing arm 34 so that the other end of the high-speed swing arm 34 does not overlap with the rocker shaft 33 as a swing fulcrum of the high-speed swing arm 34, while the HLA 41 is high-speed. Rocker shaft 3 arranged at the pivot of swing arm 34
3 is disposed on the inner side of the cylinder head 3.

On the other hand, the rocker shaft 33 for pivotally supporting the swing support end of the high-speed swing arm 34 is
Guide holes 43, 43 penetrating in the vertical direction are formed in both sides of the rocker shaft 33 so as to protrude outward in the width direction from both sides in the width direction of the high-speed swing arm 34. ing.

Then, for example, guide pins 44, 44 as guide means implanted in the cylinder head 3 are inserted through the guide holes 43, 43, and
Coil springs 45 and 45 as urging means are stretched between predetermined portions of the rocker shaft 33 and lower surfaces of both side portions of the rocker shaft 33.

An actuator 46 is disposed above the swing support end of the high-speed swing arm 34 so as to be substantially vertically opposed to the guide pins 44, 44 and the coil springs 45, 45. As shown in FIG. 2, the actuator 46 is of a hydraulic drive type provided solely at the swing support end of the above-described high-speed swing arm 34 at the widthwise intermediate portion of the swing arm 34. When moving, the swing support end of the high-speed swing arm 34 is pushed down.

At the time of lowering of the swing support end of the high-speed swing arm 34, the rocker shaft 33 is
Since the swing arm 34 moves downward while being guided by 4, the swing arm 34 swing support end is moved down while securing the swing center of the high-speed swing arm 34 swing support end.

The above-described actuator 46 is configured as shown in FIGS. That is, the actuator 46 has a cylindrical body 48 and a plunger 47 slidably disposed in the body 48, and supplies hydraulic pressure into the body 48 from a port 49 facing the back surface of the plunger 47. Then, the plunger 47 moves downward from the state shown in FIG. 6 as shown in FIG. 7, and the plurality of knock pins 5 are supplied by the hydraulic pressure supplied to the oil passage 50 in the plunger 47.
.. Project into the locking hole 52 on the body 48 side to maintain the plunger 47 in the lower movement position even when the supply oil pressure is released, while the plunger 47 in the lower movement position shown in FIG. When returning to the normal position shown in FIG. 6, when hydraulic pressure is applied to a plurality of ports 53 at positions corresponding to the outer end surfaces of the knock pins 51, the knock pins 51 enter the oil passage 50, and the coil springs 45 move. , 45 so that the plunger 47 returns to the normal position shown in FIG.

In this embodiment, as shown in FIG. 6, the swing support end of the high-speed swing arm 34 is urged to the upper side on the actuator 46 side by the spring force of the coil springs 45, 45, so that the high-speed swing When the swing support end of the arm 34 is moved upward, the high-speed tappet 36 is set at a position separated from the cam profiles of the low-speed and high-speed cams 26 and 27, and only the roller follower 38 is used for the low-speed. Since the cam 26 comes into contact with the cam profile of the cam 26, the movement of the high-speed swing arm 34, which is movable with the rocker shaft 33 as a swing fulcrum, is simultaneously transmitted to the two intake valves 10 and 11 via the respective elements 37, 39 and 40. Thus, it is possible to obtain a valve timing at a low speed with a small valve lift.

Further, as shown in FIG.
When the swing support end of the high-speed swing arm 34 is moved downward, the high-speed swing arm 34 rotates counterclockwise in FIG. Since it is set at a position where it abuts on the cam profile of the cam 27, the movement of the high-speed swing arm 34, which moves with the rocker shaft 33 as a swing fulcrum, causes the two intake valves 10, 37 to move through the respective elements 37, 39, 40. 11, the valve timing at a high speed with a large valve lift can be obtained.

By the way, the above-described second valve variable mechanism 31
Drives the remaining one intake valve 12, and the first
While the variable valve mechanism 30 includes low-speed rocker arms 39 and 40 on both sides of the high-speed swing arm 34, the second variable valve mechanism 31 includes one low-speed rocker arm 54 on one side of the high-speed swing arm. 2 and the other points are the same. Therefore, in the second variable valve mechanism 31 of FIG. 2, portions having the same operation as the first variable valve mechanism 30 are denoted by the same reference numerals , and The detailed description is omitted. 2, 55 denotes a plug hole for disposing a spark plug, and in FIGS. 1, 6, and 7, 26BC and 27BC denote base circles of the corresponding cams 26 and 27.

FIG. 8 shows a control circuit of the valve driving device of the engine. The CPU 60 controls the valve via the actuator 46 in accordance with a program stored in the ROM 61 based on necessary inputs such as the engine speed Ne and the engine load CE. Drive control of the variable mechanisms 30, 31, 32,
The RAM 62 stores necessary data and maps such as a map as shown in FIG.

Here, the above-mentioned CPU 60 does not directly drive the actuator 46, but drives the above-mentioned actuator 46 via an electromagnetic solenoid valve provided on a hydraulic supply line, but is schematically shown in FIG. ing.

In the map shown in FIG. 9, the horizontal axis represents the engine speed Ne and the vertical axis represents the engine load CE.
High load high rotation region α for driving the actuator 46
And a low-load low-rotation region β in which the actuator 46 is not driven.

FIG. 10 shows an example of changes in valve timing and valve lift by the variable valve mechanism. The first and second variable valve mechanisms 30 and 31 on the intake side are switched to a low speed mode as shown in FIG. When the first and second variable valve mechanisms 30 and 31 are switched to the high-speed mode as shown in FIG. 7, the intake and exhaust overlap period becomes longer. .

Further, a first variable valve mechanism 30 for simultaneously driving two of the three intake valves 10, 11 and 12, and a second variable mechanism for driving the remaining one of the intake valves 12.
The variable valve mechanism 31 is provided independently, and each of these mechanisms 3
If the cam profiles corresponding to 0 and 31 are different, 2
Since there is a difference between the movement of one intake valve 10 and 11 and the movement of the remaining one intake valve 12, the swirl S
It is also possible to form

The illustrated embodiment is constructed as described above, and the operation will be described below. When the CPU 60 determines that the operating state of the engine is in the low-load low-rotation region β shown in FIG. 9, the actuator 46 maintains the state shown in FIG. 6, so that the swing support end of the high-speed swing arm 34 is in the upper position. , And the tappet 36 is separated from the high-speed cam 27, so that the two intake valves 10 and 11 are connected to the first valve variable mechanism 30.
, And is driven by the low-speed cam 26.

On the other hand, when the CPU 60 determines that the operating state of the engine is in the high-load high-rotation region α shown in FIG. 9, the swing support end of the high-speed swing arm 34 is pushed down by driving the actuator 46. The swing support end of the high-speed swing arm 34 is located at the lower position as shown in FIG. 7, and the tappet 36 is in contact with the high-speed cam 27, so that the two intake valves 10, 11 can be changed by the first valve. Mechanism 30
And is driven by the high-speed cam 27 via.

That is, the above-described high-speed swing arm 3
When the tappet No. 4 is at a position away from the high-speed cam 27 (see FIG. 6), the movement of the low-speed cam 26 is controlled by the low-speed roller follower 38 and the low-speed rocker arm 39,
The valve timing at low speed transmitted to the intake valves 10 and 11 via the intake valve 40 can be obtained. On the other hand, when the tappet 36 of the swing arm 34 for high speed is in a position where it comes into contact with the cam 27 for high speed (see FIG. 7) has a high-speed cam 2
7 is transmitted to the intake valves 10 and 11 via the high-speed swing arm 34 and the low-speed rocker arms 39 and 40, so that high-speed valve timing can be obtained.

[0044] Further, since the low speed roller follower 38 described above at the time of low speed is rolling contact with the low-speed cam 26, that of course this can be reduced low speed sliding resistance of the two Low-speed rocker arms 39, 40
Since one low-speed roller follower 38 and one high-speed swing arm 34 are swingably and integrally supported by a common single pin 37, the load from the cam side and the intake valve 10 , 11 is distributed via the single pin 37 described above, so that the support rigidity of each arm, that is, the two low-speed rocker arms 39 and 40 and the one high-speed swing arm 34 is established. There is an effect that can be improved.

[0045] Here, by disposing the single high-speed swing arm 34 between the two low speed rocker arms 39 and 40 described above, a single high-speed swing arm 34 relative to the two intake valves 10, 11 Since the structure is shared, the size of the variable valve mechanism 30 and thus the entire valve driving device in the cylinder row direction of the engine can be reduced. In addition, from the high-speed swing arm 34 located between the low-speed rocker arms 39 and 40, the low-speed rocker arms 3 on both sides via a single common pin 37.
Since the load on the cam side is transmitted to 9, 40, there is an effect that the load input to the two intake valves 10, 11 can be set substantially equally.

Also, the two low-speed rocker arms 3 described above are used.
Since a single low-speed roller follower 38 is provided between the first and second low-speed roller followers 38 and 9, the two intake valves 10 and 11 share one low-speed roller follower 38. As a result, there is an effect that the dimension of the mechanism 30 in the cylinder row direction of the engine of the valve drive device can be reduced. In particular, at a low speed, the load on the low-speed cam 26 side is applied to the low-speed rocker arms 39 and 40 on both sides via the single and common pin 37 from the roller follower 38 located between the low-speed rocker arms 39 and 40 described above. Since the power is transmitted, the load input to the two intake valves 10 and 11 can be set substantially uniformly.

[0047] Moreover, by arranging a single high-speed swing arm 34 and a single low-speed roller follower 38 between the two low speed rocker arms 39 and 40 described above, for the two intake valves 10, 11 As a result, the high-speed swing arm 34 and the low-speed roller follower 38 are commonly used, so that the size of the variable valve mechanism 30 and thus the valve driving device in the cylinder row direction of the engine can be further reduced. In addition, the load input to the two intake valves 10 and 11 can be set substantially equally.

In addition, as shown in the embodiment, a tappet 36 which is in contact with the high-speed cam 27 is formed at a position offset from the center of the high-speed swing arm 34 in the cylinder row direction to one side in the cylinder row direction. Since the low-speed roller follower 38 that is in contact with the low-speed cam 26 at the position offset to the other side in the cylinder row direction is disposed, the load distribution from the cam side to the high-speed swing arm 34 in the high and low operation range of the engine. Therefore, there is an effect that metal fatigue of the high-speed swing arm 34 can be prevented and uneven wear can be prevented.

In correspondence between the configuration of the present invention and the above-described embodiment, the valve of the present invention is different from the intake valve 10 of the embodiment,
In the same manner, the camshaft corresponds to the intake camshaft 20, but the present invention is not limited to the configuration of the above-described embodiment.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a valve drive device for an engine according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is an explanatory diagram showing a layout of each intake / exhaust port with respect to a cylinder bore and a swirl generation state.

FIG. 4 is a perspective view of a first variable valve mechanism.

FIG. 5 is an exploded perspective view of the first variable valve mechanism.

FIG. 6 is an explanatory diagram showing a state in which low-speed valve timing is set.

FIG. 7 is an explanatory diagram showing a state in which high-speed valve timing is set.

FIG. 8 is a block diagram of a control circuit.

FIG. 9 is an explanatory diagram of a map stored in a RAM.

FIG. 10 is an explanatory diagram showing an example of changes in valve timing and valve lift by a variable valve mechanism.

FIG. 11 is an explanatory diagram at a low speed, showing an example of a conventional engine valve drive device.

FIG. 12 is a diagram illustrating an example of a conventional engine valve driving device at a high speed.

FIG. 13 is an explanatory view of another example of a conventional valve drive device for an engine at a low speed.

FIG. 14 is an explanatory diagram of another example of a conventional valve drive device for an engine at a high speed.

[Explanation of symbols]

10, 11 ... intake valve (valve) 15 ... valve stem 20 ... intake camshaft (camshaft) 26 ... low-speed cam 27 ... high-speed cam 34 ... high-speed swing arm 37 ... pin (single pin) 38 ... low-speed Roller followers 39, 40 ... Rocker arm for low speed

Claims (1)

(57) [Claims] 1. A valve drive device for an engine in which a low-speed cam and a high-speed cam are integrally formed on a cam shaft for driving a valve, comprising: two low-speed rocker arms abutting on upper ends of valve stems of two valves; A low-speed roller follower that is in rolling contact with the low-speed cam, and a high-speed swing arm that is swingably provided on the engine so as to be in contact with and separate from the high-speed cam, and are arranged side by side in the engine longitudinal direction. These three members are pivotally supported by a common single pin, and the high-speed swing arm is configured to be vertically movable, and a single high-speed swing arm is provided between the two low-speed rocker arms.
Wing arm and a single roller follower for low speed
Was set, the said high-speed cam is moved away with the high-speed swing arm
When the low-speed cam and low-speed roller follower abut,
The single low speed roller follower and the single pin and the low speed
Simultaneously drive two valves via speed locker arm
On the other hand, when the high-speed cam comes into contact with the high-speed swing arm,
The single high-speed swing arm and the single pin and the
Simultaneous drive of two valves via low-speed rocker arm
A valve drive for the engine that is configured to work .