JP2783131B2 - Valve train for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve train for an internal combustion engine,
In particular, the present invention relates to a valve train for an internal combustion engine in which a low speed cam and a high speed cam on a cam shaft selectively drive or stop an intake / exhaust valve.

[0002]

2. Description of the Related Art During operation of an internal combustion engine, intake and exhaust valves can be selectively switched between low-speed cams and high-speed cams in order to increase the output by driving intake and exhaust valves at opening and closing timings suitable for each operation range. Exhaust valve variable mechanism, or
An intake / exhaust valve that can selectively switch and drive low-speed cams or high-speed cams, stop intake and fuel supply to some cylinders, and perform cylinder-stop operation in order to reduce output and reduce fuel consumption in a timely manner. 2. Description of the Related Art An internal combustion engine in which a variable mechanism is attached to a valve train is known. The valve train of this kind of internal combustion engine is, for example,
As shown in FIGS. 8 and 9, the DOHC is mounted on a cylinder head 100 of a four-valve engine (not shown).
The intake and exhaust valves 101 and 102 corresponding to each cylinder are opened and closed. As shown in FIG. 8, an intake valve driving section in this valve operating system includes a rocker shaft section 103 pivotally supported by a cylinder head 100, and a rotation end driving two intake valves 101 integrally with the shaft. A mold lever 104, a rocker arm 105 provided in parallel with the T-shaped lever and pivotally supported by the rocker shaft portion 103, a cam shaft 106 provided in parallel with the rocker shaft portion 103 at a predetermined interval, and a camshaft 106. The rocker arm 105 is opposed to a low-speed cam 108 that is integrally formed and abuts a low-speed roller 107 pivotally supported by a T-shaped lever, and a high-speed cam 110 that is integrally formed on a cam shaft and abuts a high-speed roller 109 that is pivotally supported by a rocker arm 105. And a biasing means 111 for resiliently biasing the high-speed cam 110.

As shown in FIG. 8, this valve train also has a valve train on the exhaust valve drive section side as well as the intake valve side.
In the figure, the same members as those on the intake side are indicated by adding the same reference numerals and adding e at the end. In the valve train shown in FIG. 8, in particular, the main part of the variable intake / exhaust valve mechanism is formed in the rocker shaft portion 103 at the portion facing the rocker arm 105. Here, a receiving hole 112 for slidably supporting a pin 113 is formed in the rocker shaft portion 103, and this pin 113 is
4, when the high-pressure hydraulic oil is supplied to the housing hole 112, the rocker arm 105 and the rocker arm 105 are integrated with the rocker arm 105 when the high-pressure hydraulic oil is supplied to the housing hole 112. Therefore, when the operating oil is not supplied to the engagement hole 116, the rocker arm 105 is separated from the rocker shaft portion 103. During this time, the T-shaped lever 104 is driven by the low-speed cam 108, and the T-shaped lever is moved to the intake / exhaust valve 101, The valve train 102 is driven in the low speed mode. On the other hand, when the hydraulic oil is supplied to the housing hole 112, the pin 113 projects into the engagement hole 116, and the rocker arm 105 is integrated with the rocker shaft portion 103. During this time, the rocker arm 105 and the T-shaped lever 104 integrated therewith have a high lift. Driven by a high speed cam 110 with a circle,
The T-shaped lever drives the intake and exhaust valves 101 and 102, and the valve train is operated in a high-speed mode.

By the way, both rocker arms 105, 105e for transmitting the pressing force of the high-speed cams 110, 110e to the intake and exhaust valves 101, 102 are formed with protrusions a at opposite ends. Each rocker arm 10
High-speed cams 110, 11 facing the respective 5, 105e
The urging means 111, 111e which elastically urges to 0e are vertically engaged. The urging means 111 and 111e are provided between the rocker shaft portions 103 and 103e, and are attached to the cylinder head 100 via a bracket 117. As described above, in the conventional intake / exhaust valve variable mechanism, the rocker arms 105 and 105e driven by the high-speed cam are provided with the pair of vertically arranged urging means 111 and 111e. 103e.

[0005]

As described above, in the variable intake / exhaust valve mechanism provided opposite to each cylinder in the valve operating system described above, the rocker arm 105,
The urging means 111 and 111e for resiliently urging the 105e are required, and the urging means 111 and 111e are provided between the pair of rocker shaft portions 103 and 103e for intake and exhaust. For this reason, the valve opposing angle α tends to be relatively wide, and furthermore, a pair of vertical urging means 111, 111
e tends to increase the height (vertical direction in FIG. 8) of the cylinder head 100, and as a result, there is a problem in making the cylinder head 100 compact. SUMMARY OF THE INVENTION It is an object of the present invention to provide a valve train for an internal combustion engine that makes it easy to reduce the size of a cylinder head.

[0006]

In order to achieve the above object, the present invention provides a low-speed intake cam and a high-speed intake cam integrally formed on an intake camshaft of an internal combustion engine. An intake T driven by a cam to drive an intake valve
A mold lever, an intake rocker arm pivotally supported by an intake T-shaped lever and driven by a high-speed intake cam, an exhaust low-speed cam and an exhaust high-speed cam integrally formed on an exhaust cam shaft of the internal combustion engine. A cam, an exhaust T-shaped lever driven by the exhaust low-speed cam and driving an exhaust valve; an exhaust rocker arm pivotally supported by the exhaust T-shaped lever and driven by the exhaust high-speed cam; It is characterized by having biasing means disposed between the rocker arm and the exhaust rocker arm and for urging the two rocker arms toward the opposing high-speed cams.

In the first invention, the urging means includes a cylindrical casing supported by the engine body, two piston members provided in the cylindrical casing and abutting on the respective rocker arms, and an inner space between the two piston members. May be provided.

The first valve mechanism of the second invention is driven by the intake low-speed cam and the intake high-speed cam integrally formed on the intake camshaft of the internal combustion engine, and is driven by the intake low-speed cam. An intake T-shaped lever for driving a valve, an intake rocker arm pivotally supported by the intake T-shaped lever and driven by an intake high-speed cam, and exhaust gas integrally formed on an exhaust cam shaft of the internal combustion engine; Low-speed cam and high-speed exhaust cam, an exhaust T-shaped lever driven by the exhaust low-speed cam and driving an exhaust valve, and an exhaust driven by the high-speed exhaust cam pivotally supported by the exhaust T-shaped lever. A second rocker arm, and first biasing means disposed between the intake rocker arm and the exhaust rocker arm and for urging the two rocker arms toward opposed high-speed cams.
The low-speed intake cam and the high-speed intake cam integrally formed on an intake camshaft of an internal combustion engine, a rocker shaft portion at a pivot end side of the engine main body is pivotally supported, and The intake T-shaped lever drives an intake valve, and the rocker shaft is selectively supported by both sides of a rocker shaft of the intake T-shaped lever and driven by a low-speed intake cam and a high-speed intake cam. An intake rocker arm integrally connected to the engine, a low-speed exhaust cam and a high-speed exhaust cam integrally formed on an exhaust cam shaft of the internal combustion engine, and a rocker shaft portion at a pivot end side of the engine body. An exhaust T-shaped lever that is pivotally supported and whose rotating end drives an exhaust valve, and is driven by a low-speed exhaust cam and a high-speed exhaust cam that is pivotally supported on both sides of a rocker shaft portion of the exhaust T-lever. Is A second exhaust rocker arm selectively coupled integrally to the rocker shaft portion; and a second exhaust rocker arm disposed between the intake rocker arm and the exhaust rocker arm and for urging the two rocker arms toward opposed high-speed cams. And a biasing means.

In the second invention, the first valve train may be formed in one bank of the V-type engine, and the second valve train may be formed in the other bank.

In the second invention, the urging means comprises a cylindrical casing supported by the engine body, two piston members provided in the cylindrical casing and abutting on the respective rocker arms, and an inner space between the two piston members. A configuration having a spring member disposed in the first position may be adopted.

In the first and second inventions, an air passage may be formed in the cylindrical casing.

[0012]

According to the present invention, an intake rocker arm pivotally supported by an intake T-type lever for driving an intake valve and driven by a high-speed intake cam, and an exhaust T-arm for driving an exhaust valve.
An exhaust rocker arm pivotally supported by the mold lever and driven by the exhaust high-speed cam, and a single urging means can elastically urge both rocker arms toward the opposing high-speed cams. In the first invention, in particular, the urging means operates in the same manner even when the urging means has a cylindrical casing, two piston members, and a spring member. According to the second aspect, the first valve mechanism is pivotally supported by the intake T-shaped lever that drives the intake valve and is driven by the intake high-speed cam, and the exhaust rocker arm that drives the exhaust valve. An exhaust rocker arm pivotally supported by the T-shaped lever and driven by a high-speed exhaust cam, and a single first urging means can elastically urge both rocker arms toward the opposing high-speed cams, A second valve train is pivotally supported by an intake T-shaped lever for driving an intake valve and is also pivotally supported by an intake rocker arm driven by a high-speed intake cam and an exhaust T-shaped lever for driving an exhaust valve. And an exhaust rocker arm driven by the exhaust high-speed cam, and a single second urging means can elastically urge both rocker arms toward the opposing high-speed cams.

In the second invention, the first valve train is formed in one bank of the V-type engine, and the second valve train operates in the same manner when it is formed in the other bank. Second
The same effect is obtained when the first and second urging means have a cylindrical casing, two piston members and a spring member. In the first and second inventions, if an air passage is formed in the cylindrical casing, the operation of each biasing means can be ensured.

[0014]

1 shows a valve train for an internal combustion engine shown in FIG.
The OHC is mounted on a four-valve internal combustion engine (hereinafter simply referred to as engine 1). An intake path Ri and an exhaust path Re are formed in the cylinder head 2 of the engine 1 so as to communicate with each cylinder. Each of the paths is opened and closed by an intake valve 3 and an exhaust valve 4, and each intake and exhaust valve is a valve operating mechanism. Driven by In other words, the valve operating mechanism here is divided into the cylinders 2 along the center lines Li, Le (see FIG. 2) and the intake / discharge cam shafts 5, 6 (see FIG. 1) for each cylinder, and is the same as a whole. Inlet and exhaust rocker shaft parts 7, 8 arranged on the center line
Attach. Each of the camshafts 5 and 6 is integrally provided with a timing gear (not shown) at one end, and the two timing gears are connected to a crankshaft (not shown) so that the two camshafts are rotated at half the engine speed. It is configured to be rotated.

Here, all the intake and exhaust valves of each cylinder are opened and closed by the same valve operating mechanism, and are driven by the low-speed cam 12 to be driven by the rocker shaft portion as in the intake valve operating mechanism shown in FIGS. 1, 3 and 4. 7 and a rocker arm 15 driven by the high-speed cam 13. Note that both ends of the rocker shaft portion 7 are pivotally supported by a pivotal support member 201 integrally connected to the cylinder head 2. The T-shaped lever 16 has a pivotal end formed in a bifurcated shape, which drives the pair of intake valves 3 and 3 to open and close. T-shaped lever 16 and rocker arm 16,
Rollers 9 and 10 are pivotally supported at the rotating end of the shaft 15, and low and high cams 12 and 13 are opposed thereto. The rocker shaft 7, which is a pivotal support at the other end, sucks and exhausts as shown in FIG. Low-high switching means KH, which is a main part of the variable valve mechanism, is mounted.
The rocker arm 15 projects a protrusion b (see FIG. 1) directly below the rocker shaft portion 7, and the urging means 2 urges the rocker arm 15 against the high-speed cam 13 facing the protrusion b.
7 is abutted. Here, the rocker arm 15 for air supply and exhaust is
15e is resiliently urged by the single common urging means 27 to the high speed cams 13 and 13e facing each other.

The urging means 27 has a substantially cylindrical shape, and is disposed horizontally between a pair of protrusions b of the intake / exhaust rocker arms 15 and 15e. The biasing means 27 includes a cylindrical casing 271 fitted to a rocker shaft cap 202 for pivotally supporting the camshaft 8 in cooperation with the camshaft holder 200, a rocker arm 15 and an exhaust rocker arm provided in the cylindrical casing. 15 e, two piston members 272 and 273 abutting on the projection b, a spring member 274 provided between the two piston members, and an air passage 274 formed in the cylindrical casing 271. Therefore, each time a pressing force is received from the intake / exhaust rocker arms 15, 15 e, the one urging means 27 here causes the piston members 272, 273 to slide alternately within the cylindrical casing 271, and the spring member 274 becomes elastic. The rollers 10 and 10e of the intake and exhaust rocker arms 15 and 15e can be constantly held in contact with the intake and exhaust high-speed cams 13 and 13e.

Since one biasing means 27 is provided for the intake / exhaust rocker arms 15 and 15e of each cylinder, it is easy to narrow the interval between the intake / exhaust rocker arms 15 and 15e and to move upward. Can be reduced,
As a result, the valve opposing angle α can be reduced, and the cylinder head 2 accommodating the valve train can be easily made compact. As shown in FIG. 4, the low / high switching means KH includes a rocker shaft portion 7.
The pin 17 slidably supported in the receiving hole 21 and the pin 17 receiving the pressing force by the hydraulic pressure supplied to the receiving hole 21.
Are engaged with each other by switching operation against the elastic force of the spring 19, and the switching oil passage 2 communicating with the accommodation hole 21.
3 and a low-high solenoid valve 26 that connects the switching oil passage to a hydraulic pump (not shown) so as to be able to be connected and disconnected. The low / high solenoid valve 26 shown in FIGS. 2 and 4 is a three-way valve that supplies pressure oil to each of the receiving holes 21 when the valve is turned on, and supplies each of the receiving holes 21 when the valve is turned off.
Is connected to the drain side (not shown) via the switching oil passage 23. The low and high solenoid valve 26 is driven and controlled by a well-known engine control unit (ECU).

Here, when the low / high electromagnetic valve 26 is off, only the elastic force of the spring 19 acts, the pin 17 is disengaged from the engagement hole 701, and the rocker shaft portion 7 and the rocker arm 15 Separate. During this time, the T-shaped lever 16 is driven by the low-speed cam 12, the T-shaped lever drives the intake and exhaust valves 3 and 4, and the valve train is operated in the low-speed mode. When high-pressure hydraulic oil is supplied to the accommodation hole 21,
The rocker arm 15 and the rocker shaft portion are integrated with each other by projecting into the engagement hole 701 of the rocker shaft portion 7. For this reason,
When hydraulic oil is not supplied to the receiving hole 21, the rocker arm 15
Is separated from the rocker shaft portion 7, during which the T-shaped lever 1
6 is driven by the low-speed cam 12, and the T-shaped lever 16
Drives the intake valve 3. The exhaust-side low-high switching means KH operates in the same manner, and the low-high switching means KH is operated in the low-speed mode.

On the other hand, when the low / high solenoid valve 26 is on, the spring 19
The hydraulic oil in the receiving hole 21 works against the elastic force of
Project into the engagement hole 701, and the rocker arm 15 is integrated with the rocker shaft portion 7. Therefore, the intake rocker arm 15 and the T-shaped lever 16 integral therewith are driven by the high-speed intake cam 13 having a high lift circle, and the T-shaped lever 16 drives the intake and exhaust valves 3 and 4. The low-high switching means KH on the exhaust side works in the same way, and the valve train is operated in the high-speed mode. In this manner, the urging means 27 is elastically displaced and always brings the intake / exhaust rocker arms 15, 15e into contact with the intake / exhaust high-speed cams 13, 13e, regardless of whether the valve train is operated in the low or high operation mode. Can be held in contact.
FIGS. 5 to 7 show a valve train for an internal combustion engine as another embodiment of the present invention.

Here, it is mounted on a V-type 6-cylinder, DOHC, 4-valve internal combustion engine (hereinafter simply referred to as engine 1a). The engine 1a includes cylinder heads 2r and 21 in left and right banks, respectively.
The intake passage Ri and the exhaust passage Re that can communicate with each cylinder are provided in 2l.
Are formed, each flow passage is opened and closed by an intake valve 3 and an exhaust valve 4, and each intake and exhaust valve is driven by a valve operating mechanism. The first valve operating mechanism of the cylinder head 21 here is the same as the valve operating mechanism of FIG. 1 except that the number of cylinders is three.
The second valve train is equipped with low / high switching and cylinder closing means KMD. For this reason, here, the cylinder head 2
The description of l will be omitted, and the description will be mainly given of the low / high switching of the cylinder head 2r and the cylinder stopping means KMD. The same members as those in the valve train of FIG. 1 are denoted by the same reference numerals, and redundant description is omitted. The intake and exhaust valves of each cylinder of the cylinder head 2r are all opened and closed by the same valve operating mechanism, and like the intake valve operating mechanism shown in FIGS. 6 and 7, a low speed rocker arm 14 driven by a low speed cam 12, a high speed cam A T-shaped lever 16 'integrated with the high-speed rocker arm 15 and the rocker shaft 7' driven by the motor 13. The rocker shaft portion 7 'is integrally connected with a T-shaped lever 16' at the center thereof, and its left and right ends are pivotally supported by a pivot 201 integral with the cylinder head 21. The low and high speed rocker arms 14, 15 are pivoted from its left and right ends. Support.

The rotary end of the T-shaped lever 16 'is bifurcated and drives the pair of intake valves 3 and 3 to open and close. Rollers 9 'and 10 are pivotally supported at the rotating ends of the low and high rocker arms 14 and 15, and low and high cams 12 and 13 are opposed to the rollers 9' and 10, respectively. A low / high switching and cylinder closing means KMD as intake / exhaust valve operation switching means which is a main part of a variable intake / exhaust valve variable mechanism is mounted. Each of the low and high rocker arms 14 and 15 has a projection b (see FIG. 1) projecting directly below its rocker shaft portion 7 ', as shown in FIG. The same urging means 27 that elastically urges the high-speed cams 12 and 13 are in contact with each other. In addition,
The exhaust valve operating mechanism is also configured in the same manner as the intake valve operating mechanism shown in FIGS. 6 and 7. In FIGS. 5 and 8, the same members as those on the intake side are denoted by the same reference numerals, and e is added to the end thereof. Shown.

Also in this case, the low-speed rocker arms 14 and 14e for supplying and exhausting the respective cylinders are resiliently urged toward the opposing low-speed cams 12 and 12e by a single urging means 27 which is shared. High-speed rocker arms 15, 15e
Is the high-speed cam 1 by one shared urging means 27.
It is urged by 3,13e. Each of the urging means 27 has the same configuration as that described in FIGS. 1 and 3, and a duplicate description is omitted here. The two biasing means 27 provided for each cylinder can relatively narrow the intervals between the intake and exhaust rocker arms 14, 14e and 15, 15e for low speed and high speed, and project upward. The amount of the cylinder head 21. 2r can be easily made compact.

The low / high switching and cylinder rest means KMD engages with the pins 18 and 17 slidably supported in the receiving hole 21 of the rocker shaft portion 7 'and the engaging hole 22 on the low speed rocker arm 14 side. The low-speed switching oil passage 24 for supplying a hydraulic pressure for releasing the pin 18 against the elastic force of the spring 20 and the high-speed rocker arm 15 for engaging the pin 17 at the retracted position by the elastic force of the spring 19 with the hydraulic pressure of the engaging hole 21. Mating hole 701
Oil passage 23 for supplying hydraulic oil to rush
And low and high solenoid valves 27 and 26 for connecting the switching oil passages to a hydraulic pump (not shown) in an intermittent manner. The low and high solenoid valves 27 and 26 are three-way valves, and supply pressure oil to each of the receiving holes 21 when turned on, and connect each of the receiving holes 21 to the drain when turned off. The low and high solenoid valves 27 and 26 are connected to a well-known engine control unit (ECU).

As shown in FIG. 7, the low / high switching and cylinder closing means KMD constituting the second valve operating mechanism are provided with low / high solenoid valves 27,2.
When both 6 are off, the elastic forces of the springs 20 and 19 act, and only the low-speed rocker arm 14 is integrated with the T-shaped lever 16 'via the pin 18 at the locking position L1 to drive the intake valve 3 in the low-speed mode. (The exhaust valve 4 is similarly operated). At this time, the pin 17 is held at the non-locking position H1. At this time, the first valve operating mechanism of the cylinder head 2r also drives both the intake and exhaust valves in the low speed mode when both the low and high solenoid valves 27 and 26 are off. On the other hand, when both the low and high solenoid valves 27 and 26 are turned on, hydraulic pressure acts against each spring force, and the pin 18 is moved to the unlocked position L.
2, the pin 17 reaches the locking position H2, and only the high-speed rocker arm 15 is integrated with the T-shaped lever 16 'to drive the intake valve 3 in the high-speed mode (the exhaust valve 4 is also operated). At this time, the first valve operating mechanism of the cylinder head 2r also drives both the intake and exhaust valves in the high-speed mode when both the low and high solenoid valves 27 and 26 are on.

Further, when only the low solenoid valve 27 is turned on, the first valve operating mechanism of the cylinder head 2r holds the intake and exhaust valves in the low speed mode. On the other hand, the cylinder head 21
In the second valve operating mechanism, the switching chamber 24
1 only acts on the hydraulic pressure of the operating oil applied to the non-locking position L2.
Then, the pin 18 is retracted, the pin 17 is held at the unlocked position H1, and the T-shaped lever 167 is held inoperative. Therefore, the second valve mechanism of the cylinder head 2r having the cylinder-stop cylinder is operated in the cylinder-stop mode. In this way, the urging means 27 is reliably operated even when the first and second valve operating mechanisms of the cylinder heads 2r and 21 of the left and right banks of the engine 1a are operated in the cylinder-stopped or low-height operation mode. Each low-and-high-speed cam 1 that is elastically displaced and always faces each of the rocker arms 14, 14e, 15, and 15e for low- and high-speed intake and exhaust.
2, 12e, 13 and 13e can be elastically urged and held.

[0026]

As described above, according to the present invention, the intake rocker arm for selectively driving the intake valve via the intake T-lever, and the exhaust valve selectively via the exhaust T-lever. A single urging means can be resiliently urged to the opposing high-speed cams with the exhaust rocker arm that is driven in the opposite direction, making it easier to narrow the gap between the intake and exhaust rocker arms, reducing the amount of upward protrusion, and as a result The valve opposing angle can be narrowed, and the cylinder head that houses the valve operating mechanism can be easily made compact. According to the second aspect, the first valve mechanism selectively drives the intake valve via the intake T-lever, and selectively switches the exhaust valve via the exhaust T-lever. A single urging means can urge the driven exhaust rocker arm to the opposing high-speed cams, and the second valve train selectively drives the intake valve via the intake T-shaped lever. A single urging means is provided for each of the low and high rockers, and a single urging means is provided for each of the low and high rockers to selectively drive the exhaust valve through an exhaust T-shaped lever. Can be fired, resulting in first
The valve opposing angle of each of the second valve mechanisms is narrowed, and the cylinder head that houses the valve mechanisms can be easily made compact.
In the second aspect, when the first and second valve mechanisms are formed in the left and right banks of the V-type engine, the same effect can be obtained in both banks. In the first and second aspects of the invention, if the air passage is formed in the cylindrical casing, the operation of each of the urging means can be reliably performed, and the operation failure can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a valve train for an internal combustion engine as one embodiment of the present invention.

2 is a plan view of a cylinder head of an engine equipped with the valve train for an internal combustion engine of FIG. 1;

FIG. 3 is a perspective view of a low / high switching means provided in the valve train for an internal combustion engine of FIG. 1;

4 is a cross-sectional view of a low-high switching means provided in the internal combustion engine valve train shown in FIG. 1;

FIG. 5 is a plan view of a cylinder head of an engine equipped with a valve train for an internal combustion engine as another embodiment of the present invention.

6 is a perspective view of a low-high switching means provided in the valve train for an internal combustion engine of FIG. 5;

7 is a cross-sectional view of a low-high switching means provided in the internal combustion engine valve train of FIG. 5;

FIG. 8 is a sectional side view of a main part of a conventional valve train.

FIG. 9 is a perspective view of a low / high switching means of a conventional valve train.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder head 9 Roller 10 Roller 12 Low speed cam 13 High speed cam 12e Exhaust low speed cam 13e Exhaust high speed cam 14 Low speed rocker arm 15 High speed rocker arm 14e Exhaust low speed rocker arm 15e Exhaust high speed rocker arm 16 Intake T-shaped lever 16e Exhaust T-type lever 27 biasing means KH low / high switching means KMD low / high switching and cylinder closing means

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01L 13/00 301 F01L 13/00 302

Claims (6)

(57) [Claims] 1. An intake low-speed cam and an intake high-speed cam integrally formed on an intake cam shaft of an internal combustion engine, and an intake T-shaped lever driven by the intake low-speed cam to drive an intake valve. An intake rocker arm pivotally supported by an intake T-shaped lever and driven by a high-speed intake cam; a low-speed exhaust cam and a high-speed exhaust cam integrally formed on an exhaust cam shaft of the internal combustion engine; An exhaust T-shaped lever driven by the exhaust low-speed cam to drive an exhaust valve;
An exhaust rocker arm pivotally supported by a mold lever and driven by an exhaust high-speed cam; and an exhaust rocker arm disposed between the intake rocker arm and the exhaust rocker arm and for urging both rocker arms toward the opposing high-speed cams. And a valve operating device for an internal combustion engine. 2. The urging means is provided in a cylindrical casing supported by an engine main body, two piston members provided in the cylindrical casing and abutting on each rocker arm, and provided between the two piston members. 2. The valve train for an internal combustion engine according to claim 1, further comprising a spring member. 3. A first valve mechanism is driven by an intake low-speed cam and an intake high-speed cam integrally formed on an intake camshaft of an internal combustion engine, and drives the intake valve by driving the intake low-speed cam. An intake T-shaped lever, an intake rocker arm pivotally supported by the intake T-shaped lever and driven by a high-speed intake cam, and an exhaust low-speed cam integrally formed on an exhaust cam shaft of the internal combustion engine. An exhaust high-speed cam, an exhaust T-shaped lever driven by the exhaust low-speed cam and driving an exhaust valve, and an exhaust rocker arm pivotally supported by the exhaust T-shaped lever and driven by the exhaust high-speed cam. A first urging means disposed between the intake rocker arm and the exhaust rocker arm and for urging the two rocker arms toward the high-speed cams facing each other; and a second valve mechanism having an internal combustion engine On the intake cam shaft An intake low-speed cam and an intake high-speed cam integrally formed with the engine body; and an intake T-shaped lever for pivotally supporting a rocker shaft on the pivot end side of the engine main body and driving the intake valve at the rotation end side. , Which are pivotally supported on both sides of the rocker shaft of the intake T-shaped lever and driven by the intake low-speed cam and the intake high-speed cam to be selectively integrated with the rocker shaft.
Two intake rocker arms, an exhaust low-speed cam and an exhaust high-speed cam integrally formed on the exhaust camshaft of the internal combustion engine, and a rocker shaft portion at a pivot end side pivotally supported by the engine main body. An exhaust T-shaped lever whose driving end drives an exhaust valve, and a rocker selectively driven by a low-speed exhaust cam and a high-speed exhaust cam that are pivotally supported on both sides of a rocker shaft of the exhaust T-lever. Two exhaust rocker arms integrally connected to a shaft portion, and second biasing means disposed between the intake rocker arm and the exhaust rocker arm and for urging the two rocker arms toward opposed high-speed cams. A valve train for an internal combustion engine, comprising: 4. A valve for an internal combustion engine according to claim 3, wherein the first valve train is formed in one bank of the V-type engine, and the second valve train is formed in the other bank. Valve device. 5. The urging means is provided in a tubular casing supported by an engine body, two piston members provided in the tubular casing and abutting on each rocker arm, and provided between the two piston members. 4. A valve train for an internal combustion engine according to claim 3, further comprising a spring member. 6. A valve train for an internal combustion engine according to claim 2, wherein an air passage is formed in said cylindrical casing.