JP3165529B2 - Engine valve drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake valve driven through a swing arm by an intake cam provided on an intake camshaft, and an intake valve driven through a swing arm by an exhaust cam provided on an exhaust camshaft. The present invention relates to a valve driving device for an engine, comprising: an exhaust valve having a variable valve timing according to an operating state of the engine.

[0002]

2. Description of the Related Art Conventionally, as a valve driving device for an engine of the above-mentioned example, for example, US Pat. No. 4,203,397
There is a device described in the item. That is, as shown in FIGS. 11 and 12, a low-speed arm 102 driven by a low-speed cam 101 is provided, and this low-speed arm 102 is formed in a substantially rectangular frame shape when viewed from a plane. A high-speed arm 104 is disposed in a hollow portion of the arm via a pin 103, and the high-speed arm 104 is configured to be 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, there is a problem that the entire valve driving device becomes large.

[0008]

According to the first aspect of the present invention, a valve driving device is provided which has a unique structure in which one end of a swing arm is moved up and down while securing a swing center of one end of the swing arm. While avoiding an increase in the size of the swing arm, the swing arm one end can be reliably supported, and the swing arm one end can be reliably moved up and down. By this vertical movement of the swing arm one end, the valve timing can be changed to a plurality . In particular, by disposing a hydraulic drive type actuator above one end of the swing arm,
An object of the present invention is to provide a valve drive device for an engine that can stop using an actuator hydraulic pressure that drives one end of a swing arm downward by driving an actuator by hydraulic pressure at a high speed.

According to a second aspect of the present invention, in addition to the object of the first aspect, a valve drive of an engine capable of securing a stable vertical movement of one end of a swing arm with a single actuator. The purpose is to provide the device.

According to a third aspect of the present invention, in addition to the object of the first aspect, the length of the valve driving device in the cylinder row direction is reduced, and the device is reduced in size and size. It is an object of the present invention to provide a valve drive device for an engine that can perform the operation.

According to a fourth aspect of the present invention, in addition to the object of the third aspect, the valve driving device including the swing arm is compactly arranged even when the number of intake and exhaust valves is increased. It is an object of the present invention to provide a valve drive device for an engine that can perform the operation.

[0012]

According to a first aspect of the present invention, there is provided an intake valve for opening and closing an intake port, an exhaust valve for opening and closing an exhaust port, and intake and exhaust valves for driving the intake and exhaust valves. A swing arm, one end of which is pivotally supported with respect to the rocker shaft and is supported movably up and down, and the other end of which is in contact with a cam. It was allowed to move up and down, by obtaining a state not in contact with the state in contact with the cam, a valve drive device of an engine to change the valve timing in a plurality, on the swing arm end
An actuator for the downward movement of said swing arm at one end on the side provided with guide means for guiding the vertical movement of said swing arm at one end on the lower side of the swing arm end, biasing means for biasing the swing arm to the actuator side preparative provided, and the upper Symbol actuator has a plunger that is driven by hydraulic, characterized in that it is a valve driving device for an engine configured so as to move downward on the SL swing arm at one end via the plunger.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the actuator is provided solely at an intermediate portion of the one end of the swing arm in the same arm width direction, and the guide means is provided. Further, the present invention is characterized in that the biasing means is a valve drive device for an engine in which the biasing means is disposed on both sides of the actuator.

According to a third aspect of the present invention, in addition to the configuration of the first aspect, the swing arm has
It is a valve drive device for an engine constituted by a single arm that drives two valves simultaneously.

According to a fourth aspect of the present invention, in addition to the configuration of the third aspect , one of the intake valve and the exhaust valve has a three-valve structure and the other has a two-valve structure. And a valve drive device for an engine configured to simultaneously drive two of the three valve sides by the swing arm having a single arm configuration.

[0016]

Effects of the Invention According to the invention of claim 1, wherein the present invention, the accession <br/> Chueta hydraulic drive type on the upper side of the swing arm at one end, a guide means and the biasing means on the lower side, and the actuator Since the guide means and the urging means are substantially opposed in the vertical direction, it is possible to stably move one end of the swing arm up and down while securing the swing center of the one end of the swing arm by the rocker shaft.

As a result, the one end of the swing arm can be reliably supported, and the one end of the swing arm can be moved up and down without fail. The valve timing can be changed to a plurality of times by the up and down movement of the one end of the swing arm. . In addition, since it is not necessary to incorporate a spring or a latch means into the above-mentioned swing arm, it is possible to avoid an increase in the size of the valve driving device .

According to the second aspect of the present invention of this invention,
In addition to the effect of the first aspect of the present invention, a single actuator is provided at a widthwise intermediate portion of one end of the swing arm,
Since the guide means and the urging means are provided on both sides, the vertical movement of one end of the swing arm can be guided by the guide means having a relatively long span located on both sides. The movement can be ensured, and the number of actuators used can be reduced.

According to the third aspect of the present invention,
In addition to the effect of the first aspect of the present invention, the swing arm is constituted by a single arm that simultaneously drives two valves, so that the swing arm is compared with a case where separate swing arms are provided for each valve. Thus, the length of the valve driving device in the cylinder row direction can be reduced, and the device can be made compact and compact.

According to the invention described in claim 4 of the present invention,
In addition to the effect of the third aspect of the present invention, since two of the three valve sides are simultaneously driven by a swing arm having a single arm configuration, even when the number of intake and exhaust valves is increased, the number of intake and exhaust valves is increased. Thus, there is an effect that the valve driving device including the swing arm described above can be compactly arranged.

[0021]

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 connected to a plurality of camshaft bearings 22, 23.
And the exhaust camshaft 2
1 is configured to be supported by a plurality of camshaft bearings 24 and 25. Each of the camshaft bearings 22 to 2 described above
The illustration of the bearing cap attached to the upper part of 5 is omitted.

The above-described intake camshaft 20 includes 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 structure 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 below the intake camshaft 20 (see FIG. 1).
A rocker shaft 33 is provided in parallel with the swing arm 3, and a swing arm 34 whose one end (the left end in the drawing) is pivotally supported is provided on the rocker shaft 33.
4 from one end of the rocker shaft 33 side to the valve stem 15
The swing arm 34 has a recess 35 for disposing a roller follower on the other end, and a tappet 36 integrally formed on the other end.

A roller follower 38 is mounted in the roller follower disposing recess 35 by using a pin 37, and rocker arms 39 and 40 are mounted on both sides of the swing arm 34 by using the pin 37. .

Here, the roller follower 38 is located immediately below the low-speed cam 26, as shown in FIGS. 2 and 4, and the tappet 36 is located immediately below the high-speed cam 37.
Further, arc-shaped pivot portions 39a, 40a at one ends (left ends in the drawing) of the rocker arms 39, 40, respectively.
Abuts on the upper surface of a plunger 42 of a hydraulic shock adjuster 41 (hereinafter simply abbreviated as HLA) attached to the cylinder head 3, and rocker arms 39, 40.
The slipper-shaped valve abutting portions 39b and 40b at the other end (right end in the drawing) of each of the intake valves 10 and 11
At the upper end of the valve stem 15.

On the other hand, the rocker shaft 33 that pivotally supports one end of the swing arm 34 is set to have a length protruding outward in the width direction from both sides in the width direction of the swing arm 34. Guide holes 43, 43 penetrating vertically are formed in both side portions of the rocker shaft 33.

For example, guide pins 44, 44 as guide means implanted in the cylinder head 3 are inserted through the guide holes 43, 43, and the cylinder head 3
Coil springs 45, 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 one end of the 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 one end of the swing arm 34 in the widthwise middle part of the arm 34, and its plunger 47 (see FIG. 6) is moved downward. Sometimes, one end of the swing arm 34 is pushed down.

When the one end of the swing arm 34 moves downward, the rocker shaft 33 moves downward while being guided by the guide pins 44, 44, so that the one end of the swing arm 34 is moved downward while securing the swing center of the one end of the swing arm 34. It is configured to work.

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 to return to the normal position shown in FIG. 6, when energizing the hydraulic pressure to a plurality of ports 53 ... of the position corresponding to the knock pins 51 ... outer end face of, and retracted into Nokkupi down 51 ... oil passage 50, a coil spring The plunger 47 is configured to return to the normal position shown in FIG.

In this embodiment, as shown in FIG. 6, one end of the swing arm 34 is urged upward on the actuator 46 side by the spring force of the coil springs 45, 45 to move one end of the swing arm 34 upward. , The high-speed tappet 36 is moved to either the low-speed or high-speed cam 26,
Also separated from the cam profile of No. 27, the roller follower 3
Since only 8 contacts the cam profile of the low-speed cam 26, the movement of the swing arm 34, which is movable with the rocker shaft 33 as a swing fulcrum, is applied to the two intake valves 10, 11 via the respective elements 37, 39, 40. Simultaneously transmitted, it is possible to obtain a valve timing at a low speed with a small valve lift.

Further, as shown in FIG.
When one end of the swing arm 34 is moved downward, the swing arm 34 rotates counterclockwise in the drawing around the pin 37 so that the high-speed tappet 36
7 comes into contact with the cam profile, so the rocker shaft 3
The movement of the swing arm 34, which is movable with the swinging pivot 3 as a swing fulcrum, causes the two intake valves 1 to move through the respective elements 37, 39, 40.
The valve timing is transmitted to 0 and 11 at the same time, and a valve timing at a high speed with a large valve lift can be obtained. The second variable valve mechanism 31 drives the remaining one intake valve 12, and the first variable valve mechanism 30
Rocker arms 39 on both sides of the swing arm 34,
40, the second variable valve mechanism 31 has one rocker arm 54 on one side of the swing arm.
2 and the other points are the same, so the first variable valve mechanism 31 in FIG.
The same parts as those of the variable valve mechanism 30 have the same action.
The reference numerals are attached and the detailed description is omitted. Note that FIG.
Reference numeral 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 one end of the swing arm 34 is located at the upper movement position. , Two intake valves 1
0 and 11 are driven by the low speed cam 26 via the first variable valve mechanism 30.

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 actuator 46 drives one end of the swing arm 34 to be pushed down. Is located at the lower position, and the two intake valves 10 and 11 are driven by the high-speed cam 27 via the first valve variable mechanism 30.

That is, the valve timing can be changed between low speed and high speed by moving the one end of the swing arm 34 up and down while securing the swing center of the one end of the swing arm 34.

In addition, the upper part of one end of the swing arm 34
The hydraulic drive type actuator 46, the guide pins 44, 44 and the coil spring 45, 45 provided on the lower side, the upper side of the actuator 46 and the lower guide pins 4
4, 44 and the coil springs 45, 45 are substantially opposed to each other in the vertical direction, so that the swing center of the one end of the swing arm 34 by the rocker shaft 33 is secured.
The one end of the swing arm 34 can be stably moved up and down. As a result, the one end of the swing arm 34 can be reliably supported and the one end of the swing arm 34 can be moved up and down without fail.

In addition, since it is not necessary to incorporate a spring or a latch means into the swing arm 34 as in the prior art, it is possible to avoid an increase in the size of the first variable valve mechanism 30 .

[0047] is found to provide a single actuator 46 in the width direction intermediate portion of the swing arm 34 at one end, is provided with the guide pins 44, 44 and the coil spring 45, 45 on the both sides corresponding positions, located on both sides The vertical movement of one end of the swing arm 34 can be guided by the guide pins 44, 44 having a relatively long span, so that a stable vertical movement of one end of the swing arm 34 can be ensured and the number of actuators used can be reduced. Reduction can be achieved.

Further, since the swing arm 34 is constituted by a single swing arm for simultaneously driving two valves, for example, two intake valves 10 and 11, each of the intake valves 1
Compared to the case where separate swing arms are provided for 0 and 11, respectively, the length of the first variable valve mechanism 30 in the cylinder row direction can be shortened, and as a result, the valve driving device can be reduced in size and size. There is an effect that can be achieved.

In addition, since the two valves 10 and 11 out of the three valve sides (the intake side in the embodiment) are simultaneously driven by the swing arm 34 having a single arm structure, the number of intake and exhaust valves is increased. Also in this case, there is an effect that the valve driving device including the swing arm 34 described above can be arranged compactly in the valve operating chamber.

In the correspondence between the structure of the present invention and the above-described embodiment, the guide means of the present invention corresponds to the guide pin 44 of the embodiment, and similarly, the urging means corresponds to the coil spring. The present invention is not limited only to the configuration of the above 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 of a conventional engine valve drive device at low speed.

FIG. 12 is an explanatory diagram of a conventional engine valve drive device at high speed.

[Explanation of symbols]

5, 6, 7 ... intake port 8, 9, ... exhaust port 10, 11, 12 ... intake valve 13, exhaust valve 20, 21, ... camshaft 26 ... low-speed cam 27 ... high-speed cam 33 ... rocker shaft 34 ... swing arm 44: guide pin (guide means) 45: coil spring (biasing means) 46: actuator 47: plunger

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01L 13/00 301 F01L 1/18 F01L 1/26

Claims (4)

(57) [Claims] An intake valve for opening and closing an intake port, an exhaust valve for opening and closing an exhaust port, and intake and exhaust camshafts for driving the intake and exhaust valves, one end of which is connected to the rocker shaft. A swing arm that is pivotally supported so as to be swingable, vertically supported, and has the other end in contact with the cam, and one end of the swing arm is moved up and down so as not to be in contact with the cam. by obtaining a state, a valve drive device of an engine to change the valve timing in a plurality, said swing arm at one end on the upper side of the swing arm end
The actuator for the downward movement is provided, provided with guide means for guiding the vertical movement of said swing arm at one end to the lower portion of the swing arm at one end, and a biasing means for biasing the swing arm to the actuator side, and the actuator Is a plunger driven by hydraulic pressure
And one end of the swing arm through the plunger
A valve driving device for an engine configured to move down . 2. The swing arm according to claim 1, wherein
A single unit is provided at one end in the middle part of the same arm width direction,
Guiding means and urging means of the actuator
The valve drive device for an engine according to claim 1, wherein the valve drive device is disposed at a corresponding portion on both sides . 3. The swing arm drives two valves simultaneously.
The valve drive device for an engine according to claim 1, wherein the valve drive device is constituted by a single arm . 4. A three-valve structure comprising one of an intake valve and an exhaust valve.
And forming, in the other one of the second valve structure, said third valve side
The same two valves are used simultaneously with the swing arm of the single arm configuration
4. The valve drive device for an engine according to claim 3 , wherein the valve drive device is configured to be driven.