JPH10280918A - Valve system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve system for an internal combustion engine capable of opening and closing smoothly an inlet valve or an exhaust valve without lowering fuel consumption or output even during the high speed rotation of the internal combustion engine. SOLUTION: An inlet side drive shaft 21 to which the rotation of the output shaft of an engine is transmitted is rotatably supported by a cylinder head 15. The rotation of the shaft 21 is converted into the circulating movement (rotation) of first and second belt members 43 and 44 through first and second worm gears 55 and 56. These belt members 43 and 44 are provided with guide grooves 47 and 48 extending circumferentially. The guide grooves 47 and 48 are provided with curved parts 47a and 48a for opening and closing an inlet valve 19. Then, when the belt members 43 and 44 circulate, the inner walls of the guide grooves 47 and 48 (curved parts 47a, 48a) press a valve roller 57 attached to the valve 19 so as to open and close the inlet valve 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve mechanism for opening and closing an intake valve and an exhaust valve of an internal combustion engine.

[0002]

2. Description of the Related Art Generally, an internal combustion engine such as an on-vehicle engine has a piston reciprocally movable in a cylinder block, and the piston is connected to a crankshaft (output shaft) of the internal combustion engine via a connecting rod. . The reciprocating movement of the piston is converted into rotation of the crankshaft by the connecting rod.

[0003] A cylinder head is mounted on the cylinder block, and a combustion chamber is provided between the cylinder head and the head of the piston. This cylinder head has
An intake passage and an exhaust passage communicating with the combustion chamber, a fuel injection valve for injecting fuel into the combustion chamber, and a spark plug for igniting a mixed gas in the combustion chamber are provided.

[0004] The cylinder head is provided with an intake valve for communicating and shutting off the intake passage and the combustion chamber, and an exhaust valve for communicating and shutting off the exhaust passage and the combustion chamber.
Usually, the intake valve is held at a position where the intake passage and the combustion chamber are shut off by the urging force of the coil spring,
The exhaust valve is also held at a position where the exhaust passage and the combustion chamber are shut off by the urging force of the coil spring.

Further, the cylinder head is provided with an intake cam shaft and an exhaust cam shaft for opening and closing the intake valve and the exhaust valve. These camshafts are connected to a crankshaft via a timing belt, and the rotation of the crankshaft is transmitted by the timing belt.

An intake cam is provided at a position corresponding to the intake valve on the intake camshaft, and an exhaust cam is provided at a position corresponding to the exhaust valve on the exhaust camshaft. When the intake and exhaust camshafts rotate due to the transmission of rotation from the crankshaft,
The intake and exhaust cams press the intake and exhaust valves against the urging force of the coil spring at predetermined intervals. In this pressed state, the intake valve communicates the intake passage with the combustion chamber, and the exhaust valve communicates the intake passage with the combustion chamber.

In the internal combustion engine having the above structure, in the intake stroke, the intake valve is opened by the pressing force of the intake cam to communicate the intake passage with the combustion chamber, and the exhaust valve is connected to the exhaust passage by the urging force of the coil spring. And the combustion chamber. Then, the movement of the piston generates a negative pressure in the combustion chamber, and the negative pressure sucks air into the combustion chamber via the intake passage. At this time, fuel is injected from the fuel injection valve toward the combustion chamber,
The mixed gas composed of the air and the fuel is filled in the combustion chamber.

Thereafter, in the compression stroke of the internal combustion engine,
The pressure of the intake cam does not act on the intake valve, and the intake valve moves to a position where the intake passage and the combustion chamber are shut off by the urging force of the coil spring. At this time, the exhaust valve is kept in a state where the exhaust passage and the combustion chamber are shut off. The mixed gas in the combustion chamber is compressed by the movement of the piston, and the compressed mixed gas is ignited by the spark plug and explodes. Due to the explosion of the mixed gas, the piston moves in the opposite direction, and the internal combustion engine moves to the explosion stroke and obtains driving force.

Then, in the exhaust stroke of the internal combustion engine,
With the intake valve keeping the intake passage and the combustion chamber shut off, the exhaust valve is opened by the pressing force of the exhaust cam, and the exhaust passage and the combustion chamber communicate. Then, due to the movement of the piston, the mixed gas exploded in the combustion chamber is discharged to the outside as an exhaust gas through an exhaust passage.

[0010]

In the above internal combustion engine, the opening operation of the intake and exhaust valves is performed by the pressing force of the intake and exhaust cams, and the closing operation of the intake and exhaust valves is performed by the urging force of the coil spring. Will be Therefore, in order to ensure that the intake and exhaust valves perform the closing operation when the internal combustion engine rotates at a high speed, it is preferable to increase the elastic coefficient of the coil spring.

However, if the elastic modulus of the coil spring is excessively increased, when the intake and exhaust cams press the intake and exhaust valves due to the rotation of the intake and exhaust camshafts, the intake and exhaust cams, the intake and exhaust valves, A large frictional force starts to work between them. Then, this frictional force becomes a resistance at the time of driving these valves, and causes a reduction in fuel consumption and output of the internal combustion engine.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to smoothly operate an intake valve or an exhaust valve without causing a reduction in fuel consumption or output even when the internal combustion engine is rotating at a high speed. It is an object of the present invention to provide a valve mechanism for an internal combustion engine that can open and close a valve.

[0013]

In order to achieve the above object, according to the first aspect of the present invention, the internal combustion engine has a predetermined band width in the valve opening / closing direction, and the internal combustion engine moves around in rotation with rotation of an output shaft of the engine. A loop-shaped band member to be provided, and a guide groove that is provided in an annular shape in the circumferential direction with respect to the band member, a part of which is curved in the valve opening and closing direction, and is slidably engaged with the guide groove, On the other hand, there is provided a valve lifter which is connected to the valve and drives the valve to open and close as the band member moves around.

In the above configuration, when the band member moves orbiting with the rotation of the output shaft of the internal combustion engine, the guide groove of the band member moves relative to the valve lifter slidably engaged with the groove. I do. When the curved portion of the guide groove passes through a position corresponding to the valve lifter engaged with the groove, the inner wall of the guide groove pushes the valve lifter to open and close the valve of the internal combustion engine. Therefore, according to the configuration, both the opening operation and the closing operation of the valve are performed by pushing the valve lifter on the inner wall of the guide groove in the band member. Therefore, even when the internal combustion engine is rotating at a high speed, the valves can be smoothly opened and closed without increasing the driving resistance of the valves.

According to the second aspect of the present invention, the plurality of valves corresponding to the plurality of cylinders of the internal combustion engine are grouped by a predetermined number in accordance with the ignition order of the cylinders, and the band members correspond to the respective groups. In addition, the curved position and the circulating direction of the guide groove in the band members are determined according to the ignition order of the cylinders.

In the same configuration, the ignition sequence for each cylinder is different, but the valves provided for each cylinder are grouped by a predetermined number, and each group is opened and closed by a band member. The curved position and the circulating direction of the guide groove in the band members are determined according to the ignition order for each cylinder, so that the valves of each cylinder can be opened and closed at appropriate timing.

According to the third aspect of the present invention, the engagement portion of the valve lifter with the guide groove is provided with roller means engaged in the groove and rotatably supported by the valve lifter. And

According to this configuration, when the inner wall of the guide groove comes into contact with the roller means provided on the lifter when the belt member moves around and the guide groove moves relative to the valve lifter, the roller means rotates. As a result, the frictional resistance between the guide groove and the valve lifter is reduced. Therefore, the driving resistance when the valve is opened and closed can be further reduced.

According to a fourth aspect of the present invention, the connecting portion of the valve lifter with the valve supports an engaging portion with the guide groove, and the upper end of the valve is slidable in the opening and closing direction of the valve. It is configured to include a supporting body to be supported and a pair of elastic bodies each having one end fixed to the upper end of the valve and the other end sandwiching the supporting body.

In this configuration, the pair of elastic members are elastically deformed so as to further urge the valve in the valve closing direction when the valve is closed. Therefore, even if the valve thermally expands in the opening and closing direction, the thermal expansion is absorbed by the elastic deformation of the pair of elastic members, and the valve can be reliably closed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which the present invention is applied to an in-line four-cylinder automobile engine will be described below with reference to FIGS.

As shown in FIG. 1, four pistons 12 (only one is shown in FIG. 1) are provided in a cylinder block 11a of the engine 11 so as to be able to reciprocate.
Is connected via a connecting rod 13 to a crankshaft 14 which is an output shaft of the engine. The reciprocating movement of the piston 12 is converted into rotation of the crankshaft 14 by the connecting rod 13.

A cylinder head 15 is provided at the upper end of the cylinder block 11a, and a combustion chamber 16 is provided between the cylinder head 15 and the piston 12.
An intake port 17 and an exhaust port 18 provided in the cylinder head 15 are connected to the combustion chamber 16, and an intake valve 19 is connected to the intake port 17 and the exhaust port 18, respectively.
And an exhaust valve 20. The intake port 17 and the combustion chamber 16 are communicated and shut off by opening and closing the intake valve 20, and the exhaust port 18 and the combustion chamber 16 are communicated and shut off by opening and closing the exhaust valve 20.

The cylinder head 15 rotatably supports an intake-side drive shaft 21 and an exhaust-side drive shaft 22 for opening and closing the intake valve 19 and the exhaust valve 20. The drive shafts 21 and 22 on the intake side and the exhaust side are connected to the crankshaft 14 via a timing belt 26 (the connection with the crankshaft 14 is not shown). The power is transmitted to the exhaust-side drive shafts 21 and 22.

An intake pipe 30 and an exhaust pipe 31 are connected to the intake port 17 and the exhaust port 18, respectively. The inside of the intake pipe 30 and the inside of the intake port 17 form an intake passage 32, and the inside of the exhaust pipe 31 and the inside of the exhaust port 18 form an exhaust passage 33. At the upstream end in the intake pipe 30, a throttle valve 35 is provided.
Is adjusted based on the accelerator operation of the vehicle. By adjusting the opening of the throttle valve 35, the amount of air taken into the combustion chamber 16 is adjusted.

A fuel injection valve 38 for injecting fuel into the combustion chamber 16 is provided at an end (downstream end) of the intake pipe 30 on the combustion chamber 16 side. The fuel injection valve 38 allows air to pass through the intake passage 32 and
When it is sucked into 6, the fuel is injected toward the combustion chamber 16 to form a mixed gas composed of fuel and air.

On the other hand, the cylinder head 15 is provided with an ignition plug 39a. And the spark plug 3
When the mixed gas filled in the combustion chamber 16 is ignited by 9a, the power of the engine 11 is obtained by the explosion of the mixed gas, and the mixed gas after combustion is discharged to the exhaust passage 33 as exhaust gas. Will be sent out.

Next, the intake and exhaust valves 19, 20
FIGS. 2 and 3 show a valve train mechanism for opening and closing the valve.
This will be described in detail based on FIG. Since the mechanism for opening and closing the intake valve 19 and the mechanism for opening and closing the exhaust valve 20 have almost the same structure, the mechanism for opening and closing the intake valve 19 will be mainly described below. Detailed description of the mechanism is omitted.

As shown in FIG. 2, the cylinder block 11a is provided with four cylinders # 1 to # 4 sequentially in a row, and the combustion chambers 16 are provided corresponding to the cylinders # 1 to # 4, respectively. I have. Further, in the cylinder head 15, a position corresponding to each combustion chamber 16 is provided with an intake valve 19.
And an exhaust valve 20 (only the intake valve 19 is shown in FIG. 2).

Further, in the cylinder head 15, a pair of rotating shafts 41a and 41b are provided at positions corresponding to the first cylinder # 1 and the second cylinder # 2, and are provided for the third cylinder # 3 and the fourth cylinder # 4. At a corresponding position, a pair of rotating shafts 42a, 42
b is provided. These rotating shafts 41a, 41b, 4
2a and 42b are rotatably supported while extending in the same direction as the opening and closing direction of the intake valve 19. A first band member 43 having a loop shape is mounted on the pair of rotation shafts 41a and 41b, and a second band member 44 having the same loop shape is mounted on the pair of rotation shafts 42a and 42b. ing.

The first band member 43 includes a pair of rotating shafts 4.
When 1a and 41b rotate, their rotating shafts 41a and 41b
It moves around (rotates) around b. The first band member 43 is provided with the intake valves 19 of the first and second cylinders # 1 and # 2 in a state where the circumferential movement of the band member 43 is not restricted.
It is drivingly connected by a first guide groove 47 and a valve roller 57 described later. When the pair of rotating shafts 42a and 42b rotate, the second band member 44 rotates the rotating shafts 42a and 42b.
a, 42b. In the second band member 44, the intake valves 19 of the third and fourth cylinders # 3 and # 4 are provided with second guide grooves 48 and The driving connection is performed by a valve roller 57.

The first and second band members 43 and 44 are
As shown in FIG. 3, the plurality of connecting bodies 45 arranged in a loop are connected to the rotation shafts 41a and 41b or the rotation shafts 42a and 42a.
It is constituted by a so-called endless track connected to each other by a pin 46 extending in the same direction as 2b. As shown in FIG. 2, the first and second guide grooves 47, which extend annularly in the circumferential direction of the band members 43, 44, are formed on the outer peripheral surfaces of the first and second band members 43, 44. 48 are provided respectively. The first and second guide grooves 47 and 48 are provided with curved portions 47a and 48a, respectively, for bending a part of the grooves 47 and 48 downward in FIG. The guide grooves 47 and 48 have the same shape.

A pair of guide rollers 4 sandwiching the band member 43 is provided on one of the rotating shafts 41a on which the first band member 43 is mounted.
9 is attached to the other rotating shaft 41b.
3 and a face gear 50 and a guide roller 51 are provided. The face gear 50 is fixed to the rotating shaft 41b, and each of the guide rollers 49, 51 is connected to the rotating shaft 41a, 4
1b. In addition, the same band member 4 is attached to one rotating shaft 42a on which the second band member 44 is mounted.
A pair of guide rollers 52 sandwiching the same member 4 are attached to the other rotating shaft 41b.
3 and a guide roller 54 are attached. The face gear 53 is also fixed to the other rotating shaft 42b, and the guide rollers 52 and 54 are rotatable with respect to the rotating shafts 42a and 42b.

As described above, the guide rollers 49 and 5 are attached to the rotating shafts 41a and 41b and the rotating shafts 42a and 42b, respectively.
1, or by attaching the guide rollers 52, 54, the first and second band members 43, 44 are guided so that the orbital movement (rotation) is performed along a predetermined track.

On the other hand, first and second worm gears 55 and 56 attached to the intake-side drive shaft 21 mesh with face gears 50 and 53 of the rotating shafts 41b and 42b, respectively. The first and second worm gears 55 and 56 are formed to have opposite threads to each other, and transmit the rotation of the intake-side drive shaft 21 to the rotation shafts 41b and 42b. Then, the rotating shaft 4 via the first worm gear 55
When the rotation of the drive shaft 21 is transmitted to 1b, the first band member 43 moves around in the direction of arrow A. When the rotation of the rotation shaft 42b is transmitted via the second worm gear 56, the second band member 44 moves in the direction of arrow B (the direction opposite to the direction of arrow A).
Move around to.

In the first band member 43, the first guide groove 47 located between the pair of rotating shafts 41a and 41b extends in one direction (the left-right direction in the drawing).
The valve rollers 57 attached to the intake valves 19 of the cylinders # 1 and # 2 are inserted. Then, the first band member 4
3 moves in the direction of arrow A, the first guide groove 47
Moves relative to the valve roller 57. Further, due to the relative movement of the first guide groove 47, the curved portion 47a
Passes through a position corresponding to the valve roller 57,
The roller 57 moves vertically in the figure to open and close the intake valves 19 of the first and second cylinders # 1 and # 2.

In the second band member 44, portions extending in one direction (left and right directions in the drawing) of the second guide groove 48 located between the pair of rotation shafts 42a and 42b are numbered 3 and 4. The valve rollers 57 attached to the intake valves 19 of the fourth cylinders # 3 and # 4 are inserted. When the second band member 44 moves in the direction of arrow B, the second guide groove 48 moves relative to the valve roller 57.
Further, when the curved portion 48a passes through the position corresponding to the valve roller 57 due to the relative movement of the second guide groove 48, the roller 57 moves in the vertical direction in the figure and the third and fourth cylinder # 3. , # 4 intake valves 19 are opened and closed.

The four-cylinder engine 11 as in this embodiment
Then, when the first and second band members 43 and 44 move orbit with the rotation of the intake side drive shaft 21, the first cylinder # 1, the third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 2. , The intake valve 19 is opened and closed. That is, the first valve is opened and closed so that the intake valves 19 of the cylinders # 1 to # 4 open and close in the above order.
And the curved portions 47a in the second guide grooves 47, 48,
48a is positioned.

In the mechanism for opening and closing the exhaust valve 20, the first and second band members 43, 44 move orbit with the rotation of the exhaust-side drive shaft 22, and the bending portion 47.
a and 48a are 180 ° crank angles with respect to the curved portions 47a and 48a of the mechanism for opening and closing the intake valve 19.
It is provided at a position advanced by a minute.

Next, the rotating shafts 41a and 41b on which the first and second band members 43 and 44 are mounted, or the rotating shaft 42
a, 42b and their band members 43, 44
The connection structure between the air intake and exhaust valves 19 and 20 will be described in detail with reference to FIG.

As shown in FIG.
5, the rotating shafts 41a and 41b and the rotating shaft 42
a, 42b (only the rotating shafts 41b, 42b are shown in FIG. 4)
The pair of upper and lower mounting plates 58a, 58b
And a substantially U-shaped support bracket 58 having Then, the rotating shafts 41a and 41b and the rotating shaft 42
a and 42b are rotatably supported by the support bracket 58 by bearings 59a and 59b mounted on the mounting plates 58a and 58b, respectively.

On the other hand, the upper ends of the intake and exhaust valves 19 and 20 pass through the roller support 61. The roller support 61 is provided with a pin 62 projecting toward the first and second guide grooves 47 and 48. And
The valve roller 57 inserted into the first and second guide grooves 47 and 48 is rotatably attached to the pin 62.

A screw groove 63 is formed at the upper end of each of the intake and exhaust valves 19 and 20. A pair of nuts 64 a and 64 b are screwed to upper ends of the valves 19 and 20 so as to sandwich the roller support 61 so as to adjust the position. A coil spring 65a is provided between the nut 64a and the roller support 61, and a coil spring 65b is provided between the nut 64b and the roller support 61.

As described above, the intake and exhaust valves 19, 20
Are nuts 64a, 64b, coil springs 65a,
The first and second belt members 43 and 44 are drivingly connected to the first and second belt members 43 and 44 via the roller support 65 and the valve roller 57. That is, in the present embodiment, these nuts 64
a, 64b, coil springs 65a, 65b, a roller support 61, and a valve roller 57, and constitute valve lifters for the intake and exhaust valves 19, 20.
In the valve lifter, nuts 64a, 64b
When the intake and exhaust valves 19, 20 are in the closed state (FIG. 4),
9a and 20a are operated by the biasing force of the coil springs 65a and 65b, and the intake and exhaust ports 1 for the combustion chamber 16
It is adjusted so as to be pressed against the openings 7 and 18.

Next, the operation of the valve train configured as described above will be described with reference to FIGS. Engine 11
When the crankshaft 14 rotates, the rotation is transmitted via the timing belt 26 to the intake-side and exhaust-side drive shafts 2.
1 and 22. Further, the rotation of the intake-side and exhaust-side drive shafts 21 and 22 is controlled by the first and second worm gears 5.
5 and 56 to the rotating shafts 41b and 42b.
The rotation of the rotation shafts 41b and 42b causes the first and second band members 43 and 44 to rotate the rotation shafts 41a and 41b.
b, or move around the rotation shafts 42a and 42b. Since the first and second worm gears 55 and 56 are reverse-threaded with each other, the first and second worm gears 55 and 56 only rotate one intake-side drive shaft 21 and one exhaust-side drive shaft 22 in one direction. The second belt members 43 and 44 surely rotate in opposite directions.

The first and second band members 43, 44
The first and second guide grooves 47 and 48
Moves relative to the valve roller 57 of the intake and exhaust valves 19 and 20. Due to this relative movement, the first and second
When the curved portions 47a, 48a of the guide grooves 47, 48 pass through the position corresponding to the valve roller 57, the inner walls of the guide grooves 47, 48 (curved portions 47a, 48a) open and close the intake and exhaust valves 19, 20. The roller 57 is pressed to perform the operation.

That is, when the intake and exhaust valves 19 and 20 are opened, the upper inner walls of the curved portions 47a and 48a in FIG. 2 are connected to the intake and exhaust valves 19 and 20 via the valve roller 57 constituting the valve lifter. This is done by pushing down. On the other hand, the intake and exhaust valves 19, 2
The closing operation of “0” is performed by pushing the intake and exhaust valves 19 and 20 upward by the inner walls on the lower side in FIG. 2 of the curved portions 47 a and 48 a via the valve rollers 57.
In addition, the first and second guide grooves 47, 48 (curved portion 47)
a, 48a) when the inner wall contacts the valve roller 57,
The roller 57 rotates around the pin 62 of the roller support 61 to reduce frictional resistance.

In this embodiment, the first and second guide grooves 4 having the same shape are formed in the first and second belt members 43 and 44.
7 and 48, the first and second band members 43 and 44 are circulated in opposite directions, and the position of the curved portion 48a in the second band member 44 is changed to the curved portion in the first band member 45. 18 in crank angle to 47a position
The angle was advanced by 0 °. Therefore, the intake and exhaust valves 19 and 20 of each of the cylinders # 1 to # 4 can easily be connected to the first cylinder ##.
The first and third cylinders # 3, # 4, and # 2 are opened and closed in that order.

According to the embodiment described in detail above, the following effects can be obtained. When the first and second band members 43 and 44 move around with the rotation of the crankshaft 14, the band members 43 and 44
44, the inner walls of the first and second guide grooves 47, 48 (curved portions 47a, 48a)
The valve roller 57 constituting the valve lifter is pushed so that the valves 9 and 20 open and close. Thus the intake and exhaust valves 1
Both the opening operation and the opening operation of 9 and 20 are performed by the inner walls of the first and second guide grooves 47 and 48 (curved portions 47 a and 48 a) being pressed against the valve roller 57. Therefore, even when the engine 11 is rotating at high speed, unlike the conventional case, the valves 19 and 20 are smoothly moved without increasing the driving resistance of the valves 19 and 20, that is, without lowering the fuel consumption and output of the engine. Can be opened and closed.

When the valve roller 57 contacts the inner walls of the first and second guide grooves 47 and 48, the roller 5
7 rotates around the pin 62, so that the frictional resistance when the first and second band members 43, 44 circulate is reduced, and the driving resistance of the intake and exhaust valves 19, 20 is further reduced. Can be.

In general, in the four-cylinder engine 11, the opening and closing operations of the intake and exhaust valves 19 and 20 are performed by the first cylinder # 1, the third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 2
It is performed in order. In this embodiment, the first and second guide grooves 4 having the same shape are formed in the first and second band members 43 and 44.
7 and 48, the first and second band members 43 and 44 are circulated in opposite directions, and the position of the curved portion 48a in the second band member 44 is changed to the first band member 45.
At a crank angle with respect to the position of the curved portion 47a in FIG.
Since the valve is advanced by 80 °, the intake and exhaust valves 1
9, 20 can be easily opened and closed in the above order.

First and second worm gears 55 and 56 having opposite threads are attached to one intake side drive shaft 21 and one exhaust side drive shaft 22, and intake is performed via the worm gears 55 and 56. -Side and exhaust-side drive shafts 21 and 22
Is transmitted to the rotation shafts 41b and 42b, respectively. Therefore, the first and second band members 43 and 44 can be easily orbited in opposite directions by simply rotating one intake-side drive shaft 21 and one exhaust-side drive shaft 22 in one direction. it can.

The orbital movement of the first and second band members 43 and 44 is performed by the guide rollers 49 and 5 of the rotating shafts 41a and 41b.
1, or the guide rollers 52 of the rotating shafts 42a and 42b,
Guided by 54. Therefore, it is assumed that the orbital movement of the first and second band members 43 and 44 is along a predetermined trajectory, and the band members 43 and 44 are rotated by the rotating shafts 41a and 41b.
Alternatively, it is possible to preferably prevent the rotation shafts 42a and 42b from coming off.

Generally, intake and exhaust valves 19, 20
In some cases, the heat expansion of the engine 11 causes the length in the opening / closing direction to increase. In particular, since the exhaust gas is blown to the exhaust valve 20, the above-described thermal expansion easily occurs. In this regard, in this embodiment, the positions of the nuts 64a and 64b of the intake and exhaust valves 19 and 20 are adjusted, and
When the valves 9 and 20 are closed, the valve portions 19a and 20a of the valves 19 and 20 are pressed against the openings of the intake and exhaust ports 17, 18 by the urging force of the coil springs 65a, 65b. Therefore, even when the thermal expansion occurs, the thermal expansion is absorbed by the expansion and contraction of the coil springs 65a and 65b, and the intake and exhaust valves 1
During the closing operation of the valves 9, 20, the valves 19, 20 can reliably close the openings of the intake and exhaust ports 17, 18.

The present embodiment can be modified, for example, as follows. In the present embodiment, the present invention is applied to both the valve operating mechanism of the intake valve 19 and the valve operating mechanism of the exhaust valve 20, but may be applied to only one of the valve operating mechanisms.

In the valve operating mechanism of this embodiment, the intake valve 19 or the exhaust valve 20 is opened and closed by the first band member 43 and the second band member 44.
When the number of cylinders in one is other than four, the number of band members may be one or three or more according to the number of cylinders.

In this embodiment, the case where the present invention is applied to the in-line four-cylinder engine 11 has been described.
The present invention may be applied to other types of engines such as a cylinder, a V-type 8-cylinder engine, and an in-line 6-cylinder engine.

In this embodiment, one first and second guide groove 4 is provided in each of the first and second belt members 43 and 44.
Although 7, 48 are provided, the present invention is not limited to this. For example, the first band member 43 has separate first guide grooves 47 for the first cylinder # 1 and the second cylinder # 2, and the second band member 44 has the third cylinder # 3. A second guide groove 48 may be provided for each of the second and fourth cylinders # 4 and # 4.

In the present embodiment, one intake-side drive shaft 2
1, all the intake valves 19 are driven to open and close, and one exhaust-side drive shaft 22 drives all the exhaust valves 20 to open and close. However, the present invention is not limited to this. For example, the intake and exhaust valves 19, 2 of the first and second cylinders # 1, # 2
0 and an exhaust side drive shaft 21 for opening and closing the
22 and intake-side and exhaust-side drive shafts 21 and 22 for opening and closing the intake and exhaust valves 19 and 20 of the third and fourth cylinders # 3 and # 4 may be provided separately. in this case,
The first band member 43 is orbitally moved by one of the intake-side and exhaust-side drive shafts 21 and 22, and the second band member 44 is orbited by the other intake-side and exhaust-side drive shafts 21 and 22.

In the present embodiment, the face gears 50 and 5
3 and the first and second worm gears 55 and 56, the rotation of the intake-side and exhaust-side drive shafts 21 and 22 is controlled by the rotation shafts 41b and 41b.
Although the rotation is transmitted to 42b, the rotation may be transmitted by a bevel gear or the like instead.

An appropriate elastic body may be provided in place of the coil springs 65a and 65b constituting a part of the valve lifter.

[0062]

According to the first aspect of the present invention, since both the opening operation and the closing operation of the valve are performed by pushing the valve lifter on the inner wall of the guide groove in the band member, the high rotation speed of the internal combustion engine is increased. At times, the valves can be opened and closed smoothly without increasing the driving resistance of the valves.

According to the second aspect of the present invention, the valves provided in each cylinder are divided into groups of a predetermined number, and each group is opened and closed by the band member. Since the curved position and the circulating movement direction of the guide groove in these band members are determined according to the ignition order for each cylinder, the valves of each cylinder can be opened and closed at appropriate timing.

According to the third aspect of the present invention, when the belt member moves around and the guide groove moves relative to the valve lifter, when the inner wall of the guide groove comes into contact with the roller means provided on the lifter, the guide member is moved. The roller means rotates to reduce the frictional resistance between the guide groove and the valve lifter. Therefore, the driving resistance when opening and closing the valve can be further reduced.

According to the fourth aspect of the present invention, the pair of elastic members are elastically deformed so as to further urge the valve in the valve closing direction when the valve is closed, and the valve thermally expands in the opening and closing direction. Then, the thermal expansion is absorbed by the elastic deformation of the pair of elastic bodies. Therefore, even when thermal expansion occurs in the valve, the valve can be reliably closed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an engine to which a valve train according to an embodiment is applied.

FIG. 2 is an enlarged view showing a valve operating mechanism that drives an intake valve to open and close.

FIG. 3 is a plan view showing a configuration of first and second band members.

FIG. 4 is a cross-sectional view showing a connection structure between intake and exhaust valves and first and second band members, and a support structure of a rotating shaft that moves the band members around.

[Explanation of symbols]

11 engine, 14 crankshaft, 19 intake valve, 20 exhaust valve, 43 first band member, 44
... second band member, 47 ... first guide groove, 48 ... second guide groove, 57 ... valve roller, 61 ... roller support,
65a, 65b: coil springs.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02B 75/18 F02B 75/18 L

Claims (4)

[Claims] 1. A loop-shaped band member having a predetermined band width in a valve opening / closing direction of an internal combustion engine, and moving around with rotation of an output shaft of the engine; A guide groove partially curved in the valve opening / closing direction, and is engaged with the guide groove so as to be slidable on the one hand, and is connected to the valve on the other hand, and the valve is connected to the orbital movement of the band member. And a valve lifter for driving the valve to open and close. 2. A plurality of valves corresponding to a plurality of cylinders of the internal combustion engine are grouped by a predetermined number according to the ignition order of the cylinders, and a plurality of the band members are provided corresponding to the respective groups. 2. The valve operating mechanism for an internal combustion engine according to claim 1, wherein the curved position and the circling direction of the guide groove in the band members are determined according to the ignition order of the cylinders. 3. The valve lifter according to claim 1, wherein the engagement portion of the valve lifter with the guide groove includes roller means engaged in the groove and rotatably supported by the valve lifter. Valve train of an internal combustion engine. 4. A supporter for connecting the valve lifter with the valve, the supporter supporting an engagement portion with the guide groove and supporting an upper end of the valve slidably in the opening and closing direction of the valve; The valve train of an internal combustion engine according to any one of claims 1 to 3, comprising a pair of elastic bodies each having one end fixed to an upper end of the valve and the other end sandwiching the support.