JP2003239712A - Valve control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve control device with high degree of freedom of design for controlling a valve timing and an amount of lift with a simple constitution. <P>SOLUTION: A control arm 30 is turned with a control shaft 12 by a motor. One end of a follower 40 is pivotably supported to the control arm at an eccentric position different from the control shaft 12. A pivot cam 50 is pivotably mounted to the control shaft 12. A rocker arm 60 bonded to a shaft 70 of an intake valve is butted to a pivot cam surface 56 of the pivot cam 50 by an arm roller 62. When a valve cam 2 is rotated at one round and the pivot cam 50 is pivoted at one reciprocation with the follower 40, the intake valve is opening/closing-driven. When a rotation position of the control arm 30 is changed by the motor, a distance between a part where a second roller 44 and the pivot cam 50 are butted and the control shaft 12 is varied. At the same rotation angle position of the cam shaft 1, a circumferential position of the valve cam 2 butted to a first roller 42 is varied. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an internal combustion engine (hereinafter,
The present invention relates to a valve control device that controls the opening / closing timing (hereinafter, "opening / closing timing" is referred to as valve timing) of an intake valve or an exhaust valve of an "internal combustion engine" and the lift amount according to an operating state.

[0002]

2. Description of the Related Art Conventionally, as a valve control device for controlling a valve timing and a lift amount of an intake valve or an exhaust valve of an engine according to an operating state of the engine, a cam having a cam profile different in an axial direction is provided on a camshaft. It is known to change a cam profile for driving an intake valve or an exhaust valve by reciprocating a shaft in an axial direction.

However, in the valve control device that changes the cam profile that drives the intake valve or the exhaust valve by moving the cam shaft in the axial direction, the lift amount decreases and the valve opening period shortens, or the lift amount increases. The maximum lift position does not change even when the valve opening period is extended. That is, the maximum lift position cannot be changed with the change in the lift amount. Therefore, the degree of freedom in design for controlling the valve timing and the lift amount of the intake valve or the exhaust valve is low.

For example, in the case of a valve control device for an intake valve, if the lift amount is reduced and the valve opening period is shortened, the maximum lift position does not change, so the valve opening timing moves to the retard side. When the opening timing of the intake valve moves to the retard side, the piston in the cylinder of the engine descends before the intake valve opens, so the inside of the cylinder becomes negative pressure. Then, pumping loss occurs and fuel consumption is reduced.

In the valve timing control device disclosed in Japanese Unexamined Patent Publication No. 6-117207, the cam of the camshaft is formed in a taper shape in the axial direction, and the cam profile is different in the axial direction. Rotational phase changing means for changing the phase is provided. Thus, the maximum lift position is independently controlled regardless of the change in the lift amount of the intake valve or the exhaust valve.

[0006]

However, in the valve timing control device disclosed in Japanese Patent Laid-Open No. 6-117207, the drive means for axially reciprocating the camshaft and the drive means for the rotational phase varying means are provided. Both are required, which complicates the configuration. Further, when the camshaft is driven by both driving means, it is difficult to control the lift amount and phase of the intake valve or the exhaust valve during the transition with high accuracy.

An object of the present invention is to provide a valve control device having a high degree of freedom in design, which controls the valve timing and the lift amount with a simple structure. Another object of the present invention is to provide a valve control device that controls the valve timing and lift amount of an intake valve to improve fuel efficiency.

[0008]

According to the valve control device of the first aspect of the present invention, when the control shaft is rotated by the rotation drive means to change the rotational position of the control member, the same rotation of the cam shaft is performed. At the angular position, the circumferential position of the valve cam that contacts the transmission member changes. That is, when the rotation driving means rotates the control member to change the rotation position of the control member, the swing cam receives the driving force of the valve cam from the transmission member and opens and closes the intake valve or the exhaust valve. The maximum lift position of the valve or exhaust valve changes.

Further, when the rotation shaft of the control member is changed by rotating the control shaft by the rotation driving means, the distance between the control shaft and the position where the swing cam and the transmission member contact each other changes. The swing angle width of the transmission member is the same even if the rotational position of the control member changes. However, even if the swing angle width of the transmission member is the same, the swing angle width of the swing cam changes when the distance between the position where the swing cam and the transmission member abut and the control shaft changes.
The swing angle width of the swing cam increases as the distance between the control shaft and the position where the swing cam and the transmission member contact each other decreases, and decreases as the distance increases. The larger the swing angle width of the swing cam, the larger the lift amount of the intake valve or the exhaust valve, and the smaller the swing angle width of the swing cam, the smaller the lift amount of the intake valve or the exhaust valve.

By rotating the control shaft by one rotation drive means to change the rotational position of the control member, the maximum lift position of the intake valve or the exhaust valve is changed and the lift of the intake valve or the exhaust valve is changed. The amount increases and decreases. It is possible to realize a valve control device having a high degree of freedom in design that controls the valve timing and the lift amount with a simple configuration.

According to the second aspect of the present invention, there is provided the valve control device for the intake valve, wherein the rotation drive means is arranged so that the rotation drive means becomes longer in the direction in which the distance between the control shaft and the position where the rocking cam and the transmission member contact each other increases. When is rotated, the lift amount of the intake valve is reduced, and the circumferential position of the valve cam that abuts the transmission member at the same rotational angle position of the cam shaft moves to the advance side. That is, when the lift amount of the intake valve becomes small and the valve opening period becomes short, the valve opening period of the intake valve moves to the advance side. Even if the lift amount becomes small, the intake valve can be kept in the open state when the valve opening timing is moved to the advance side and the piston in the cylinder descends, so pumping loss can be reduced and fuel consumption can be improved.

According to the third aspect of the present invention, there is provided the valve control device for the intake valve, wherein the rotation drive means is arranged so that the distance between the control shaft and the position where the rocking cam and the transmission member come into contact becomes longer. When is rotated, the timing of opening the intake valve does not change, and the timing of closing the intake valve moves to the advance side.
That is, even if the lift amount of the intake valve becomes small and the valve opening period becomes short, the valve opening timing of the intake valve does not change. Since the intake valve can be kept open when the piston in the cylinder descends, pumping loss can be reduced and fuel consumption can be improved.

According to the valve control device of the fourth aspect of the present invention, since the contact surface of the rocking cam that contacts the transmission member is a flat surface, the rocking cam can be easily manufactured. Claim 5 of the present invention
According to the mounted valve control device, the oscillating cam surface moves from the valve opening start position of the intake valve or the exhaust valve to the maximum lift position, and the introduction portion with a small increase rate of the speed of lifting the intake valve or the exhaust valve, And an increasing portion that is formed closer to the maximum lift position than the inlet portion and has a larger rate of increase in the speed of lifting the intake valve or the exhaust valve than the introduction portion. The rocking cam drives the intake valve or the exhaust valve to open and close with one reciprocating rocking motion. Therefore, the oscillating cam opens the intake valve or the exhaust valve from the introducing portion to the increasing portion, and closes the intake valve or the exhaust valve from the increasing portion to the introducing portion. The moving speed of the intake valve or the exhaust valve when driven in the introduction portion is slow, and the moving speed of the intake valve or the exhaust valve when driving in the increasing portion is fast. Since the seating noise when the intake valve or the exhaust valve is closed is reduced, the operating noise can be reduced.

According to the sixth aspect of the valve control device of the present invention, the transmission member has a first roller that comes into contact with the valve cam and a second roller that comes into contact with the swing cam. Since the friction when the driving force of the valve cam is transmitted from the transmission member to the swing cam is reduced, the fuel consumption of the engine that drives the valve cam is improved.

According to the valve control device of the seventh aspect of the present invention, the first roller and the second roller are installed coaxially, so that the structure is simplified and the manufacturing cost is reduced.
According to the valve control device of the eighth aspect of the present invention, the rotational position at which the control member is attached to the control shaft can be adjusted by the adjusting member. It is possible to reduce variations in valve timing or lift amount for each cylinder due to manufacturing errors, assembly errors, etc.
Combustion in each cylinder is stable and fuel efficiency is improved.

When the oscillating cam makes one reciprocation by one rotation of the valve cam, the accelerating motion of the oscillating cam is between the valve open position and the maximum lift position and between the maximum lift position and the valve close position. It becomes the maximum respectively. According to the valve control device of the ninth aspect of the present invention, the opening of the intake valve or the exhaust valve is started on the retard side of the rotational angle position of the valve cam at which the maximum acceleration of the swing cam swings. The oscillating cam surface has a cam profile. That is, the intake valve or the exhaust valve is closed on the advance side of the rotation angle position of the cam shaft where the acceleration of the swing cam swing is maximized. Even if the lift amount becomes smaller and the valve opening period becomes shorter, the intake valve or exhaust valve closes before the maximum acceleration of the swing cam swings. Seating noise can be reduced.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment showing an embodiment of the present invention will be described with reference to the drawings. A valve control system for an intake valve using the valve control device of the present invention is shown in FIG. The engine control unit (ECU) 100 inputs an accelerator opening, water temperature, and other sensor signals for detecting engine operation,
Sending control signals to ignition devices, injectors, and other control devices. The motor 20 of the valve control device 10 shown in FIG.
A drive current is supplied from the control circuit 102.

Valve timing adjusting devices 110 and 112 for adjusting the valve timing independently of the valve control device 10 are provided on the intake valve camshaft 1 and the exhaust valve camshaft 5, respectively. The valve timing adjusting devices 110 and 112 transmit the driving force of the crankshaft to the camshafts 1 and 5 and adjust the rotational phase of the camshafts 1 and 5 with respect to the crankshaft. The rotation angle position of the control shaft 12 is controlled by a motor 20 as a rotation driving means.

As shown in FIG. 1, the control arm 30 as a control member is fixed to the control shaft 12 by a bolt 34 as an adjusting member. By loosening the bolt 34, the mounting rotational position of the control arm 30 with respect to the control shaft 12 can be adjusted. The follower 40 as a transmission member is swingably supported at one end by the control arm 30 at an eccentric position 32 different from the control shaft 12. A first roller 42 and a second roller 44 are coaxially rotatably attached to the other end of the follower 40. First roller 42
Is in contact with the valve cam 2 installed on the camshaft 1. The second roller 44 is in contact with a swing cam 50 described later on the side opposite to the position where the first roller 42 and the valve cam 2 are in contact with each other with the follower 40 interposed therebetween. The first roller 42 contacts the valve cam 2 and rotates, and the second roller 44 moves the swing cam 50.
The contact between the follower 40 and the valve cam 2 causes the friction between the follower 40 and the swing cam 50 to decrease.

The swing cam 50 is swingably attached to the control shaft 12. Spring 16 as biasing means
Has one end locked to a locking member 14 installed on a cylinder head or the like, and the other end locked to a locking portion 52 installed on the swing cam 50. The swing cam 50 is biased toward the second roller 44 by the biasing force of the spring 16. The contact surface 54 of the swing cam 50 that contacts the second roller 44 is a flat surface.

The rocker arm 60 includes an arm roller 62.
Is in contact with the swing cam surface 56 of the swing cam 50.
The rocker arm 60 has one end rotatably attached to the support shaft 64. The other end of the rocker arm 60 is connected to the intake valve shaft 70. The shaft 70 is coupled to the seat member 72, and the spring 74 biases the seat member 72 in the direction in which the intake valve closes. The intake valve is opened and closed by rotating the rocker arm 60 around the support shaft 64.

Next, the operation of the valve control device 10 will be described. When the valve cam 2 makes one rotation, the follower 40 swings once in the X and Y directions of FIG. The swing cam 50 swings back and forth together with the follower 40 once the valve cam 2 makes one rotation. When the valve cam 2 reaches the rotation angle position shown in FIG. 1 (A), the swing cam 50 starts swinging, and when the valve cam 2 reaches the rotation angle position shown in FIG. 1 (B), it swings. The cam 50 reaches the maximum swing position.

The oscillating cam surface 56 has an introducing portion 56a on the side where the intake valve starts to open, and an increasing portion 56b on the maximum lift position side with respect to the introducing portion 56a. As shown in FIG. 4, the rate of increase in the speed at which the swing cam 50 lifts the intake valve from the valve opening start position to the maximum lift position is determined by the introduction portion 56.
The increasing portion 56b is larger than a. Therefore, the lift speed of the intake valve gradually increases while the intake valve starts to lift and the arm roller 62 of the rocker arm 60 is in contact with the introduction portion 56a. The arm roller 62 is the introduction part 5
The lift speed of the intake valve rapidly increases when it contacts the increasing portion 56b through 6a.

When the swing cam 50 reaches the maximum lift position and returns toward the valve opening start position, the arm roller 62 contacts the swing cam surface 56 in the order of the increasing portion 56b and the introducing portion 56a. The lift characteristic shown in FIG. 4 is reversed. That is, the seating speed when the intake valve is closed becomes slow. Therefore, the seating sound of the intake valve is reduced.

The lift amount of the valve cam 2, that is, the swing position of the swing cam 50, the acceleration at which the swing cam 50 swings due to the rotation of the valve cam 2, and the lift amount of the intake valve have the characteristics shown in FIG. Have. The position where the swing cam 50 starts swinging is on the advance side of the position where the intake valve starts opening the valve. The maximum swing acceleration of the swing cam 50 is reached during the period from the start of swing to the maximum lift position, that is, the maximum swing position, and the return from the maximum swing position to the swing start position. Has become. The cam profile of the oscillating cam surface 56 is such that the intake valve lift is retarded from the position where the oscillating acceleration of the oscillating cam 50 becomes maximum from the time when the oscillating cam is started until the maximum oscillating position is reached. In other words, the intake valve is closed on the advance side of the position where the swing acceleration of the swing cam 50 is maximum during the period from the maximum swing position to the return to the swing start position. Has been done. As will be described later, even if the rotation position of the control arm 30 is changed by the motor 20 to reduce the lift amount of the intake valve, the intake valve is advanced on the advance side of the position where the swing acceleration of the swing cam 50 is maximum. Is set to close. Since the intake valve closes before the maximum swing acceleration of the swing cam 50, the seating noise of the intake valve can be reduced.

Next, the motor 20 is rotated to rotate the control arm 30 to the position shown in FIG. The distance between the portion where the second roller 44 and the swing cam 50 contact each other and the control shaft 12 is longer than the position shown in FIG. Further, the circumferential position where the valve cam 2 comes into contact with the first roller 42 moves toward the advance side with respect to FIG. 1 at the same rotation angle position of the cam shaft 1. That is, the rocking cam 50 starts rocking at an advanced position as compared with FIG.

The swing angle width of the follower 40 is determined by the first roller 4
It is the same even if the position where 2 abuts the valve cam 2 moves to the advance side or the retard side of the valve cam 2. However, the second roller 4
When the distance between the control shaft 12 and the position where the rocking cam 4 and the rocking cam 50 contact each other becomes longer, the rocking angle width of the rocking cam 50 becomes smaller than the rocking angle width of the same follower 40. On the contrary, when the distance between the contact point between the second roller 44 and the swing cam 50 and the control shaft 12 becomes shorter, the swing angle width of the swing cam 50 becomes larger than the swing angle width of the same follower 40. Become.

As shown in FIG. 3, when the distance between the contact point between the second roller 44 and the swing cam 50 and the control shaft 12 becomes long and the swing angle width of the swing cam 50 becomes small, the intake valve of the intake valve moves. The lift amount becomes smaller. The smaller the lift amount, the shorter the valve opening period. As described above, since the first roller 42 contacts the valve cam 2 on the advance side, the maximum lift position of the intake valve advances. In the present embodiment, when the lift amount of the intake valve becomes small and the valve opening period becomes short, the maximum lift position is advanced. At this time, as shown in FIG. 6, the position where the intake valve starts opening the valve is set to substantially the same timing, and the valve closing timing is moved to the advance side. Since the intake valve can be kept open when the piston in the cylinder descends, negative pressure in the cylinder can be prevented and pumping loss can be reduced. Therefore, fuel efficiency is improved.

In this embodiment, the valve control device for the intake valve is set so that the maximum lift position is advanced when the lift amount is reduced. However, the intake valve is retarded so that the maximum lift position is retarded when the lift amount is decreased. It is also possible to set a valve control device for the. For example, in FIG. 1, if the relative rotation direction of the camshaft 1 is opposite to that of the follower 40, the maximum lift position moves to the retard side when the lift amount decreases. Even when the configuration of the present invention is applied to the valve control device that controls the valve timing and lift amount of the exhaust valve, the valve control device can be easily adjusted so that the maximum lift position advances or retards when the lift amount is reduced. Can be set. The drive means for controlling the valve timing and the lift amount is the motor 20.
With such a simple configuration, it is possible to realize a valve control device having a high degree of freedom in design for controlling the valve timing and the lift amount.

In this embodiment, the motor is used as the rotation driving means for rotating the control shaft 12, but the accelerator and the control shaft 1 are used.
2 and the wire link, and control shaft 1 according to the accelerator opening
The rotation position of 2 may be controlled. In this embodiment, the valve timing adjusting device 100 that adjusts the valve timing of the intake valve independently of the valve control device 10 is used in the valve control system. However, the valve timing of the intake valve and the lift amount of the intake valve can be adjusted only by the valve control device 10. You may control.

[Brief description of drawings]

FIG. 1 is an operation diagram showing a valve control device according to an embodiment of the present invention, in which (A) shows a swing start position of a swing cam,
(B) shows the maximum swing position.

FIG. 2 is a schematic configuration diagram showing a valve control system using the valve control device of the present embodiment.

FIG. 3 is an operation diagram showing the valve control device when the lift amount is reduced, (A) shows a swing start position of the swing cam, and (B) shows a maximum swing position.

FIG. 4 is a characteristic diagram showing a relationship between a swing angle of a swing cam and a lift amount of an intake valve.

FIG. 5 is an explanatory diagram showing a relationship among a valve cam lift amount, a swing cam acceleration, and an intake valve lift amount.

FIG. 6 is a characteristic diagram showing a relationship among a crank angle, a lift amount, and a valve timing.

[Explanation of symbols]

1 camshaft (camshaft) 2 valve cam 10 valve controller 12 control axes 16 spring (biasing means) 20 motor (rotating drive means) 30 control arm (control member) 32 Eccentric position 40 Follower (Transmission member) 42 First roller 44 Second roller 50 swing cam 54 Contact surface 56 Swing cam surface 56a Introduction 56b increment 60 rocker arms

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Jun Yamada             14 Iwatani Shimohakaku-cho, Nishio-shi, Aichi Stock Association             Company Japan Auto Parts Research Institute (72) Inventor Shoji Hayashi             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO F-term (reference) 3G018 AB04 BA18 CA13 DA02 DA03                       DA10 DA15 DA19 DA29 EA35                       FA01 FA06 FA07 FA08 FA26                       GA02 GA07 GA14 GA17 GA18                       GA32

Claims (9)

[Claims] 1. A valve control device that receives a driving force from a camshaft to control opening / closing timing and a lift amount of an intake valve or an exhaust valve of an internal combustion engine, a control shaft, and a control member that rotates together with the control shaft. Rotational drive means for rotating the control shaft to change the rotational position of the control member, and a valve cam provided on the camshaft so as to be swingably attached to the control member at an eccentric position different from the control shaft. A transmission member that abuts and swings around the eccentric position by the rotation of the valve cam; and a transmission member that is swingably attached to the control shaft and that is opposite to the position where the valve cam abuts the transmission member. An oscillating cam surface that abuts on the transmission member, oscillates around the control shaft as the transmission member oscillates, and opens and closes the intake valve or the exhaust valve within a predetermined rotation angle range. And a swing cam having the same, wherein when the rotation drive means rotates the control shaft to change the rotation position of the control member, the valve comes into contact with the transmission member at the same rotation angle position of the cam shaft. A valve control device characterized in that a circumferential position of a cam changes, and a distance between a position where the swing cam and the transmission member come into contact with each other and the control shaft changes. 2. A valve control device for controlling the opening / closing timing and lift amount of an intake valve, wherein the valve is rotated in a direction in which a distance between a position where the rocking cam and the transmission member contact and the control shaft increases. 2. The circumferential position of the valve cam, which comes into contact with the transmission member at the same rotational angle position of the cam shaft, moves toward the advance side when the dynamic drive means rotates the control member. Valve control device. 3. The intake valve is opened when the rotation drive means rotates the control member in a direction in which a distance between the control shaft and a position where the swing cam and the transmission member contact each other increases. 3. The timing of closing the intake valve does not change, and the timing of closing the intake valve moves to the advance side.
The valve control device described. 4. The valve control device according to claim 1, wherein an abutment surface of the rocking cam that abuts the transmission member is a flat surface. 5. The oscillating cam surface includes an introduction portion having a small rate of increase in the speed at which the intake valve or the exhaust valve is lifted from the valve opening start position of the intake valve or the exhaust valve toward the maximum lift position. 5. The increasing portion, which is formed closer to the maximum lift position than the introducing portion, and has an increasing rate of increasing speed of lifting the intake valve or the exhaust valve is larger than that of the introducing portion. The valve control device according to any one of claims. 6. The transmission member includes a first roller that comes into contact with the valve cam, and a second roller that comes into contact with the swing cam, according to any one of claims 1 to 5. Valve control device. 7. The valve control device according to claim 6, wherein the first roller and the second roller are coaxially installed. 8. The valve control device according to claim 1, further comprising an adjusting member capable of adjusting a rotational position for attaching the control member to the control shaft. 9. A cam profile for starting the opening of the intake valve or the exhaust valve on the retard side of the rotational angle position of the cam shaft when the acceleration at which the swing cam swings is maximum. 9. The valve control device according to claim 1, wherein the swing cam surface has.