JP2003013716A - Variable valve timing device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change the rotating phase of a camshaft to a most-retarded phase or an intermediate phase in a specified operation without causing the lowering of control accuracy in the normal operation of an internal combustion engine. SOLUTION: A first rotor 41 is drivingly connected to a crankshaft, and rotated relative to the camshaft 23. A housing 40 is rotated relative to a first rotor 41 by the hydraulic pressure of hydraulic oil 71 supplied thereto through a specified passage. A second rotor 51 is installed on the camshaft 23 so as to be rotated integrally with each other, and rotated relative to the housing 40 by the hydraulic pressure of hydraulic oil 71 supplied thereto through another passage. Accordingly, the rotating phase of the camshaft 23 relative to the crankshaft varies within a specified range. The device comprises a torsional coiled spring 86 for elastically energizing the housing 40 in the spark advancing direction, and a rotation restricting means for restricting the relative rotation of the housing 40 in further spark advancing direction when the rotating phase of the camshaft 23 is positioned at an intermediate phase within a specified range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing varying device that changes the operation timing of at least one of an intake valve and an exhaust valve in an internal combustion engine according to the engine operating state.

[0002]

2. Description of the Related Art In a general internal combustion engine, the rotation of a crankshaft is transmitted to a camshaft, and a cam of the camshaft periodically pushes down an intake / exhaust valve to reciprocate to move the intake / exhaust passage. Open and close. In this type of internal combustion engine, the rotational phase of the camshaft with respect to the crankshaft is always constant. On the other hand, in recent years, a valve timing varying device has been mounted on an internal combustion engine for the purpose of improving output, improving emission, and the like. The variable device changes the rotation phase of the cam shaft with respect to the crank shaft,
The operation timing (valve timing) of at least one of the intake and exhaust valves is to be changed.

As a valve timing variable device of this type, there is, for example, a valve timing adjusting mechanism disclosed in Japanese Patent Application Laid-Open No. 11-241608. The adjusting mechanism includes a housing and a rotor. The housing is rotatably supported by the cam shaft and is drivingly connected to the crank shaft by a chain or the like. The rotor has a plurality of vanes on its outer periphery, and is attached to the cam shaft so as to be integrally rotatable while being housed in the housing. Inside the housing, hydraulic chambers are formed on both front and rear sides with respect to the rotation direction of each vane. And
Depending on the operating state of the internal combustion engine, hydraulic oil of the engine is supplied to or discharged from each hydraulic chamber, whereby the rotor rotates relative to the housing, and the rotational phase of the camshaft with respect to the crankshaft changes. For example, at the time of idling, the rotation phase of the cam shaft with respect to the crank shaft is set to the most delayed state (the most retarded angle phase). In this most retarded phase, the operation timing of the intake valve becomes the latest with respect to the rotation of the crankshaft, so that combustion is stabilized and the idle rotation speed is suppressed.

In the above valve timing adjusting mechanism, a spring is used which biases the rotor in the direction of advancing (advancing) the rotational phase of the cam shaft. With this spring, the rotational phase of the camshaft is advanced from the most retarded phase to the intermediate phase while the engine is stopped. Therefore, the internal combustion engine is started in a state where the rotation phase of the camshaft is in the intermediate phase, and the emission deterioration at the start is suppressed.

[0005]

By the way, in order to surely advance the rotational phase of the camshaft from the most retarded phase to the intermediate phase only by the urging force of the spring while the internal combustion engine is stopped,
It is desirable to use a spring having a large spring force. But,
This makes it difficult to change the rotational phase of the camshaft to the most retarded phase during idling. This is because it is necessary to urge the rotor with a force that overcomes the spring force in order to achieve the most retarded phase, but the engine rotation speed is low during idling and the hydraulic pressure is accordingly low.

On the other hand, it is considered that the pressure receiving area is increased by increasing the number of vanes. By doing this, the rotor can be rotated against the spring force even with a low hydraulic pressure, and the rotational phase of the camshaft can be set to the most retarded phase at the time of idling, but the reaction of the rotor becomes sensitive and the hydraulic pressure will slightly increase. Even if it changes, the rotor will rotate. As a result, it becomes difficult to control the camshaft to a desired rotation phase when the internal combustion engine is in a normal operating state except during idling, which causes a new problem that the control accuracy is reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent a decrease in control accuracy during normal operation of an internal combustion engine and to perform a specific operation such as start-up or idle operation. Another object of the present invention is to provide a valve timing varying device for an internal combustion engine that can change the rotational phase of the camshaft to the most retarded angle phase or the intermediate phase.

[0008]

[Means for Solving the Problems] Means for achieving the above-mentioned objects and their effects will be described below. According to the first aspect of the present invention, the first rotor that is drivingly connected to the crankshaft of the internal combustion engine and that rotates relatively to the valve driving camshaft, and the pressure of the working fluid of the internal combustion engine that is supplied through a predetermined passage. And a housing that rotates relative to the first rotor and the working fluid that is attached to the cam shaft so as to rotate integrally with the housing while being disposed in the housing, and that is supplied through a passage different from the predetermined passage. Second rotor for rotating the camshaft relative to the crankshaft within a predetermined range by rotating relative to the housing based on the pressure of the second rotor, and biasing means for elastically biasing the housing in the advance direction. And a rotation restricting means for restricting relative rotation of the housing in the advance direction when the rotation phase of the camshaft reaches an intermediate phase within the predetermined range. Eteiru.

According to the above structure, the rotation of the crankshaft is transmitted to the valve via the first rotor, the housing, the working fluid of the internal combustion engine, the second rotor, the camshaft and the like. By this transmission, the valve opens and closes at a predetermined operation timing (valve timing). The valve timing is changed within a predetermined range by the housing rotating relative to the first rotor, the second rotor rotating relative to the housing, and the cam shaft rotating relative to the crankshaft. It In other words, the range in which the rotational phase of the housing with respect to the first rotor and the rotational phase of the second rotor with respect to the housing are combined, that is, the range of relative rotation that the second rotor can take with respect to the first rotor is the above-mentioned ""Predeterminedrange", and the rotation phase of the camshaft is changed within this predetermined range.

In this specification, regarding the rotational phase of the cam shaft, the slowest rotational phase of the "predetermined range" is referred to as "the most retarded angle phase", and the most advanced rotational phase is the "most advanced angle phase". ". Regarding the rotational phase of the housing and the second rotor, the slowest one of the rotational phase ranges is expressed as the "latest phase" and the most advanced one is expressed as the "most advanced phase". And

The relative rotation of the housing is performed on the basis of the pressure of the working fluid of the internal combustion engine supplied through the predetermined passage, the elastic biasing force of the biasing means in the advance direction, and the like. However,
Relative rotation of the housing in the advance direction is restricted by the rotation restricting means.

The relative rotation of the second rotor depends on the pressure of the working fluid supplied through a passage different from the predetermined passage,
It is performed based on the rotation torque of the cam shaft and the like. here,
The rotational torque by the cam shaft is a torque that tends to delay the rotational phase of the cam shaft due to the reaction force that accompanies the opening and closing of the valve, and increases as the rotational speed of the cam shaft decreases.

When the range that the second rotor can actually take is the "movable range", this movable range changes depending on the rotation phase of the housing with respect to the first rotor. When the rotation phase of the housing is the "slowest phase", the second
The movable range of the rotor is the maximum, that is, the predetermined range (“the most retarded phase” to “the most advanced phase”). When the housing relatively rotates within the range from the "latest phase" to immediately before being regulated by the rotation regulating means, the movable range of the second rotor is "the most advanced state" from the rotational phase of the housing at that time. It is limited to the range up to "angular phase". On the other hand, when the rotation phase of the housing is restricted by the rotation restriction means, the movable range of the second rotor is changed from the “intermediate phase” to the “maximum retardation phase” within the predetermined range. It is limited to the range of "advance phase". Here, from the viewpoint of the rotational phase with respect to the crankshaft, the "most advanced phase" of the housing and the "intermediate phase" of the camshaft are the same.

The second rotor may or may not be affected by the elastic biasing force of the biasing means depending on the rotational phase of the housing. When the rotation phase of the housing is within the range where it is not restricted by the rotation restricting means (the "latest phase" to the "advanced phase"), the second rotor becomes the latest phase in the movable range. , Housing and second
The rotor and the rotor are connected to each other so that power can be transmitted in the rotation direction. Therefore, the elastic biasing force of the biasing means applied to the housing is also transmitted to the second rotor via the housing.

On the other hand, when the relative rotation of the housing is restricted by the rotation restricting means, the second rotor is not affected by the elastic biasing force. This is because the rotation of the rotation restriction means prevents the housing from rotating relative to the advance angle any more, the connection state in the rotation direction is released, and the power transmission from the housing to the second rotor is cut off. Because it is.

Therefore, by adjusting the pressure of the working fluid applied to the housing and the second rotor according to the operating state (including stop) of the internal combustion engine, the rotational phase of the camshaft is variously changed as follows. It is possible to

For example, when an operation for stopping the internal combustion engine is performed, the rotation speed of the crankshaft decreases and the pressure of the working fluid decreases. Therefore, the elastic biasing force of the biasing means overcomes the pressure of the working fluid, and the housing tends to relatively rotate in the advance direction. On the other hand, as described above, the rotational torque of the camshaft increases as the rotational speed decreases, and
The rotor tries to rotate relative to the retard angle side. At this time, by using as the urging means an elastic urging force having a magnitude that overcomes the rotational torque, it is possible to relatively rotate the housing in the advance direction against the rotational torque. This relative rotation is regulated by the rotation regulating means, and the housing is in the "most advanced phase". Further, the second rotor comes into contact with the housing, and the relative rotation of the second rotor in the retard direction is restricted, and as a result, the cam shaft is in the "intermediate phase". In this way, the rotation phase of the cam shaft is
The intermediate phase can be reliably achieved by the time the internal combustion engine is started.

Also, for example, when the internal combustion engine is idle,
The rotation phase of the camshaft can be set to the "most retarded phase" as follows. Generally, at idle, the rotation speed of the crankshaft decreases and the pressure of the working fluid decreases.
If this pressure is below the elastic biasing force of the biasing means, the housing relatively rotates in the advance direction, and it is difficult to change the rotation phase of the housing to the "most retarded phase". . However, by increasing the pressure receiving area of the housing, a force of a magnitude that overcomes the elastic biasing force of the biasing means is generated, and the housing is relatively rotated in the retard direction, and the rotation phase is set to the "latest phase". It is possible to change.

On the other hand, in the second rotor, if the pressure in the retard angle direction due to the working fluid is set to be higher than the pressure in the advance angle direction, it follows the relative rotation of the housing in the retard angle direction. The second rotor also relatively rotates in the same direction.
The relative rotation of the second rotor stops when it comes into contact with the housing that has reached the "latest phase". As a result, the rotation phase of the camshaft becomes the "most retarded phase".

Further, during the normal operation of the internal combustion engine except during the idling or starting, the rotational phase of the housing is changed to the "most advanced phase", and then the second rotor is relatively rotated, whereby the camshaft is rotated. Rotation phase is "intermediate phase"
To "the most advanced phase" can be changed. The "most advanced phase" of the housing is, for example,
It can be realized by reducing the pressure of the working fluid acting on the housing. This is because the elastic biasing force of the biasing means overcomes the pressure of the working fluid and the housing relatively rotates in the advance direction, and the relative rotation is restricted to the "most advanced phase" by the rotation restriction of the rotation restricting means. This is because

When the relative rotation of the housing is restricted by the rotation restricting means, as described above,
The elastic biasing force of the biasing means is not transmitted to the second rotor. Therefore, with respect to the second rotor, unlike the housing, it is not necessary to increase the pressure receiving area in order to realize the “maximum retardation phase” of the cam shaft. Therefore, it is possible to suppress the adverse effect due to the increase in the pressure receiving area, that is, the second rotor's hypersensitivity reaction to the pressure change of the working fluid. It becomes easy to control the camshaft to a desired rotation phase, and control accuracy is improved.

In this way, according to the first aspect of the invention, the camshaft of the camshaft can be operated during a specific operation such as starting or idling without degrading the control accuracy during normal operation of the internal combustion engine. The rotation phase can be changed to the “most retarded phase” and the “intermediate phase”.

According to a second aspect of the present invention, in the first aspect of the present invention, a first lock mechanism for connecting the housing, the relative rotation of which is regulated by the rotation regulating means, to the first rotor so as not to be relatively rotatable. Is further equipped.

According to the above construction, when the pressure of the working fluid decreases and falls below the elastic biasing force of the biasing means, for example, when the internal combustion engine stops, the housing relatively rotates in the advance direction. When this relative rotation is restricted by the rotation restricting means and the housing is in the "most advanced phase", the housing is connected (locked) to the first rotor by the first lock mechanism so as not to be relatively rotatable. That is, the rotational phase of the housing is kept at the "most advanced phase". Along with this, the movable range of the relative rotation of the second rotor is limited to the range from the “intermediate phase” to the “advanced phase” advanced from the “maximum retarded phase” in the predetermined range. . On the other hand, the rotation torque of the cam shaft causes the second rotor to relatively rotate toward the retard side, but when the second rotor contacts the locked housing, further relative rotation in the retard direction is restricted. To be done. As a result, the rotation phase of the cam shaft can be maintained at the "intermediate phase".

Further, for example, when the pressure of the working fluid acting on the housing is forcibly reduced during the normal operation of the internal combustion engine, the rotational phase of the housing is "the most advanced phase" in this case as well. ”, And is connected (locked) to the first rotor by the first lock mechanism. Therefore, with the housing locked as described above,
It is possible to limit the movable range of the relative rotation of the second rotor and prevent the rotational phase of the camshaft from becoming slower than the “intermediate phase”.

According to a third aspect of the present invention, in the second aspect of the present invention, the housing is connected to the first rotor by the first lock mechanism when the internal combustion engine is stopped, and the second rotor is used. When the rotation phase of the cam shaft becomes the intermediate phase due to the relative rotation of
Second connecting the rotor to the housing in a non-rotatable manner
It also has a lock mechanism.

According to the above construction, when the internal combustion engine is stopped, the housing is locked by the first lock mechanism and the rotational phase is kept at the "most advanced phase". In addition, when the rotation phase of the camshaft becomes an intermediate phase due to the relative rotation of the second rotor toward the retard side, the second rotor is coupled (locked) to the housing by the second lock mechanism so as not to be relatively rotatable. Therefore, by locking the housing and the second rotor, it is possible to hold the camshaft in an intermediate phase suitable for starting while the internal combustion engine is stopped.

According to a fourth aspect of the present invention, in the second or third aspect of the present invention, the working fluid is a working oil whose viscosity changes according to temperature. A drain mechanism is provided for discharging the hydraulic oil when the internal combustion engine is stopped.

If at least one of the housing and the second rotor is not properly locked by the lock mechanism when the internal combustion engine is stopped, it is necessary to lock it at the next start. However, when the engine is started at an extremely low temperature, the viscosity of the working oil as the working fluid is high, so the working oil may hinder the movement of the housing and the second rotor.

On the other hand, according to the above configuration, when the internal combustion engine is stopped, the working fluid in the housing is discharged by the drain mechanism in accordance with the stop. Therefore, even if the engine is started at an extremely low temperature as described above, the amount of hydraulic oil that hinders the movement of the housing and the second rotor is small in the housing. Therefore, even if the lock is not properly performed when the internal combustion engine is stopped, it is possible to relatively rotate the housing and the second rotor at the time of starting the engine so that the rotation phase of the cam shaft becomes the intermediate phase. Particularly, immediately after the internal combustion engine is stopped, the temperature of the hydraulic oil is high and the viscosity is low, so that the oil can be discharged smoothly.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the drain mechanism is provided in a discharge passage communicating the inside and outside of the housing, and is provided in the middle of the discharge passage, and the internal combustion engine is provided. And an on-off valve that opens only when the vehicle is stopped.

According to the above construction, when the internal combustion engine is operating, the opening / closing valve of the drain mechanism is closed and the discharge passage is closed. Therefore, it becomes difficult for the working fluid to be discharged to the outside of the housing through the discharge passage. On the other hand, when the internal combustion engine is stopped, the open / close valve is closed and the discharge passage is opened, so that the working fluid is easily discharged to the outside of the housing through the discharge passage.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a vehicle is equipped with a gasoline engine (hereinafter, simply referred to as engine) 11 which is a form of an internal combustion engine. The engine 11 includes a cylinder head 12 and a cylinder block 14 having a plurality of cylinders (cylinders) 13. Piston 15 housed in each cylinder 13
Is connected to a crankshaft 17 via a connecting rod 16. After the reciprocating motion of each piston 15 is converted into a rotary motion by the connecting rod 16,
It is transmitted to the crankshaft 17.

The combustion chamber 18 is formed above the pistons 15 between the cylinder block 14 and the cylinder head 12. The cylinder head 12 is provided with an intake port 19 and an exhaust port 20 which communicate with each combustion chamber 18. An intake valve 21 and an exhaust valve 22 are reciprocally supported by the cylinder head 12, and the camshaft 2 is provided above the valves 21 and 22.
3 and 24 are rotatably provided respectively. Sprocket 25, 2 provided at the end of each cam shaft 23, 24
6 is drivingly connected to the crankshaft 17 by a chain 27.

When the crankshaft 17 is rotated,
The rotation of the two sprocket wheels 25,
26. When the cam shafts 23 and 24 rotate as the sprockets 25 and 26 rotate, the corresponding valves 21 and 22 reciprocate to open and close the ports 19 and 20. A timing pulley and a timing belt may be used instead of the sprockets 25 and 26 and the chain 27 in order to transmit the rotation of the crank shaft 17 to the cam shafts 23 and 24.

An intake passage 28 for guiding the air outside the engine 11 to the combustion chamber 18 is connected to the intake port 19, and a fuel injection valve 31 for injecting fuel toward each intake port 19 is connected to the intake port 28. It is attached to the passage 28.
Then, the air-fuel mixture including the fuel injected from each fuel injection valve 31 and the intake air is introduced into each combustion chamber 18. The introduced air-fuel mixture is exploded and burned by ignition of the ignition plug 32 attached to the cylinder head 12. The high temperature and high pressure combustion gas generated at this time causes the piston 15 to reciprocate, the crankshaft 17 is rotated, and the driving force of the engine 11 is obtained. An exhaust passage 33 is connected to the exhaust port 20, and the combustion gas generated in the combustion chamber 18 is discharged to the outside of the engine 11 through the exhaust passage 33.

In the engine 11 having the above structure, the camshaft 2
A force (rotational torque) for delaying the rotational phase of the cam shafts 23, 24 is applied to 3, 24 by the reaction force associated with the opening / closing drive of the valves 21, 22. This rotation torque increases as the rotation speed of the cam shafts 23 and 24 decreases.

A valve timing varying device 34 is provided on the intake camshaft 23. The variable device 34 changes the operation timing (valve timing) of the intake valve 21 to the angle (crankshaft) of the crankshaft 17 by changing the phase of the camshaft 23 with respect to the rotation of the sprocket 25 and eventually the crankshaft 17 within a predetermined range. A device for continuously changing the angle, and is driven by fluid pressure (hydraulic pressure). It should be noted that the delay of the rotation phase is expressed as "retard" and the advance of the rotation phase is expressed as "advance".

Next, the structure of the valve timing varying device 34 will be described with reference to FIGS. As shown in FIG. 2, the cam shaft 23 is rotatably supported by the cylinder head 12 in a predetermined direction (the direction indicated by arrow A in FIGS. 3 and 4). A case 37 having a sprocket 25, a case body 35, and a cover 36 is attached to the end of the cam shaft 23 so as to be relatively rotatable. Sprocket 2
5 is rotatably supported on the outer periphery of the end of the cam shaft 23, and is drive-connected to the crank shaft 17 by the chain 27 as described above. The case body 35 is fastened to the sprocket 25 with bolts 38 and the like.
The cover 36 has an annular step portion 36a at the center thereof, and is fastened to the case body 35 with bolts 39 or the like. Thus, the sprocket 25, the case body 35, and the cover 36 are connected to each other and integrated. The sprocket 25 and the case body 35 may be integrally formed.

As shown in FIGS. 2 and 3, in the case 37, the central portion of the cover 36, more specifically, the step portion 3
A first rotor 41 is fastened around the 6a by bolts 42 and the like. Therefore, the first rotor 41 is the case 3
7, and is connected to the crankshaft 17 via a chain 27 and the like, and is relatively rotatable about the camshaft 23. The first rotor 41 includes a plurality of vanes 43 extending radially.

A housing 40 is arranged in the case 37 so as to be rotatable relative to the case 37. The housing 40 includes a first housing 44, a plate 46, and a second housing 47. First housing 44
Are arranged so as to be relatively rotatable around the first rotor 41. On the inner peripheral surface of the first housing 44, a plurality of (the same number as the vanes 43) protrusions 45 protruding toward the center,
It is formed at substantially equal angles in the circumferential direction. Then, in a state where the inner peripheral surface of the first housing 44 slidably contacts the tip of the vane 43, each of the protrusions 45 is adjacent to the vane 43.
It is located in between and the tip of the protrusion 45 slidably contacts the outer peripheral surface of the first rotor 41.

The first housing 44 is rotatable relative to the first rotor 41 when the pressure of the fluid is received by the protrusion 45. In addition, in the first rotor 41 and the first housing 44, a large number of vanes 43 and protrusions 45 are formed in order to increase the pressure receiving area. In the present embodiment, “12” is set as these numbers, but this is only an example and can be changed as appropriate.

As shown in FIGS. 2 and 4, the plate 46
The second housing 47 is arranged closer to the cam shaft 23 than the first housing 44 in the case 37. The plate 46 and the second housing 47 are integrally rotatably connected to the first housing 44 by a pin 48. On the inner peripheral surface of the second housing 47, a plurality of protrusions 49 projecting toward the center are formed at substantially equal angles in the peripheral direction.

The rotational phase of the housing 40 becomes the "latest phase" when at least one protrusion 45 of the first housing 44 comes into contact with the rear vane 43 in the rotational direction of the cam shaft 23 (FIG. 12). reference). Further, in the same rotation phase, at least one protrusion 45 is
When it comes into contact with the vane 43 on the front side in the rotation direction of, the phase becomes the "most advanced phase" (see FIGS. 14 and 16).

A second rotor 51 is provided in the second housing 47.
Are arranged, and the rotor 51 is integrally rotatably fastened to the cam shaft 23 by bolts 52 and the like. Second rotor 5
1 has a plurality of vanes 53 extending radially.
Then, the outer peripheral surface of the central portion of the second rotor 51 has a protrusion 49.
Each vane 53 is slidably in contact with the tip end of the second housing 47 and is slidably in contact with the inner peripheral surface of the second housing 47.

The second rotor 51 applies the pressure of the fluid to the vane 5
By being received by 3, it rotates relative to the housing 40. Due to this relative rotation, the rotational phase of the cam shaft 23 with respect to the crank shaft 17 changes within a predetermined range. The numbers of the protrusions 49 and the vanes 53 are the same as those of the protrusions 45 and the vanes 4.
Less than three. In the present embodiment, these numbers are set to "4", but can be changed as appropriate.

The rotational phase of the second rotor 51 becomes the "latest phase" when at least one vane 53 comes into contact with the rear projection 49 in the rotational direction of the cam shaft 23 (see FIG. 13). Further, the same rotational phase becomes the “most advanced phase” when at least one vane 53 comes into contact with the front projection 49 in the rotational direction of the cam shaft 23.

The hydraulic pressure of the working oil 71, which is the working fluid of the engine 11, is used as the pressure of the fluid for relatively rotating the second rotor 51. Specifically, the space between the adjacent protrusions 49 in the second housing 47 is divided into two spaces by the vanes 53. Among these, in the rotational direction of the cam shaft 23, the space on the front side of the vane 53 is the retard side hydraulic chamber 54, and the rear side space is the advance side hydraulic chamber 55.

In the cylinder head 12, the camshaft 23, the second rotor 51, etc., the retard side oil passage 56 connected to the retard side hydraulic chamber 54 and the advance side oil passage 57 connected to the advance side hydraulic chamber 55.
And are formed. A supply passage 59 is provided in both oil passages 56 and 57 via an oil control valve (OCV) 58.
And two discharge passages 61 are connected. OCV58
Is an electromagnetically driven flow control valve, which is controlled by an electronic control unit (ECU) 62 for engine control. The supply passage 59 is connected to an oil pan 64 via an oil pump 63, and both discharge passages 61 are directly connected to the oil pan 64. The oil pump 63 is drivingly connected to the crankshaft 17 and operates in accordance with the operation of the engine 11 to suck and discharge the hydraulic oil 71 from the oil pan 64. As is well known, the hydraulic oil 71 has a characteristic that its viscosity decreases as the temperature of the engine 11 rises.

5 to 7 show the internal structure of the OCV 58. The casing 65 of the OCV 58 is formed with a retard side port 65a, an advance side port 65b, a supply port 65c, and discharge ports 65d and 65e. The retard side oil passages 56, 56 are respectively connected to the ports 65a-65e.
The advance side oil passage 57, the supply passage 59, and both discharge passages 61 are connected. Inside the casing 65, a spool 68 having four valve portions 66 and elastically biased by a spring 67 is reciprocally housed. In the OCV 58, the ECU 62 duty-controls the energization time of the electromagnetic solenoid 69. Spool 6 according to this control
8 is changed, and each port 65a is changed by the valve unit 66.
~ 65e is opened and closed.

For example, when the duty ratio is 0%,
As shown in FIG. 5, the spring 67 extends and the spool 68 is arranged at one end side (right side in FIG. 5). The retard side oil passage 56 and the supply passage 59 communicate with each other, and the hydraulic oil 7 in the oil pan 64
1 is supplied to the retard side hydraulic chamber 54. Further, the advance side oil passage 57 communicates with one (left side in FIG. 5) discharge passage 61,
The hydraulic oil 71 in the advance hydraulic chamber 55 is returned to the oil pan 64. As a result, the second rotor 5 with respect to the housing 40
1 relatively rotates in the direction opposite to the rotation direction of the cam shaft 23 (retard angle direction). This relative rotation, as shown in FIG.
The vane 53 stops when it comes into contact with the rear projection 49 in the rotational direction of the cam shaft 23.

When the duty ratio is 100%, the spool 68 compresses the spring 67 and is arranged on the other end side (left side in FIG. 6) as shown in FIG. The advance side oil passage 57 and the supply passage 59 communicate with each other, and the working oil 71 in the oil pan 64 is supplied to the advance side hydraulic chamber 55. Further, the retard side oil passage 56 communicates with the other (right side in FIG. 6) discharge passage 61, and the hydraulic oil 71 in the retard side hydraulic chamber 54 is transferred to the oil pan 6.
Returned to 4. As a result, the second rotor 51 rotates relative to the housing 40 in the rotation direction (advance direction) of the cam shaft 23. This relative rotation is stopped by the vane 53 coming into contact with the front projection 49 in the rotation direction of the cam shaft 23.

Therefore, by arbitrarily changing the duty ratio between 0 and 100%, the hydraulic oil is supplied to and discharged from the retard side hydraulic chamber 54 and the advance side hydraulic chamber 55, respectively. The hydraulic pressure within 55 can be adjusted. By this adjustment, the rotational phase of the second rotor 51 can be arbitrarily changed within the range from the “latest phase” to the “leading phase”.

Further, the OCV 58 includes the second housing 4
It functions as a second drain mechanism that discharges the hydraulic oil 71 inside 7 to the outside of the second housing 47 when the engine is stopped. Specifically, the ECU is stopped when the engine 11 is stopped.
The power supply to the electromagnetic solenoid 69 is stopped by 62.
As the energization is stopped, in the OCV 58, as shown in FIG. 7, the spring 67 extends further than that in FIG.
Moves to the electromagnetic solenoid 69 side more than when the duty ratio is 0%. When the spool 68 moves to this position, both the retard angle side oil passage 56 and the advance angle side oil passage 57 communicate with the discharge passage 61. 65a-65
The size and position of e are set.

As shown in FIGS. 2 and 3, the housing 4
The hydraulic pressure of the hydraulic oil 71 is used as the pressure of the fluid for rotating 0 relative to the first rotor 41.
Specifically, in the space between the adjacent protrusions 45 in the first housing 44, the vane 4 is arranged in the rotation direction of the cam shaft 23.
A space on the rear side of 3 is a retard side hydraulic chamber 72a. The space on the front side of the vane 43 is an advance side hydraulic chamber 72b.

The following mechanism is employed as a means for supplying the hydraulic oil 71 to the retard side hydraulic chamber 72a and discharging the hydraulic oil 71. As shown in FIGS. 2 and 8, in the boundary portion of the first rotor 41 with the cover 36, the passage 7 for communicating the retard angle side hydraulic chamber 72a and the step portion 36a with each other.
3a is formed. A passage 73b is formed in a portion of the first rotor 41 near the plate 46 to connect the advance-side hydraulic chamber 72b and the central hole portion 74. A housing hole 76 is formed in the chain cover 75 of the engine 11 at a position on the same axis as the cam shaft 23, and a valve body 77 is housed therein so as to be reciprocally movable and rotatable. The cam shaft 23 side end of the valve body 77 penetrates the cover 36 and enters the central hole 74. The valve body 77 is always elastically biased toward the chain cover 75 by a spring 78 arranged in the central hole 74.

The chain cover 75 has a plunger 79.
And a solenoid valve 81 having an electromagnetic coil 80 is attached. The plunger 79 enters the accommodation hole 76 and is connected to the valve body 77 via the bearing 82. The electromagnetic coil 80 is excited by energization, and moves the plunger 79 toward the cam shaft 23 side against the spring 78. The energization of the electromagnetic coil 80 is controlled by the ECU 62. Specifically, the electromagnetic coil 80 is energized (ON) when the engine 11 is in operation, and the energization is stopped (OFF) when the engine 11 is stopped.

The valve body 77 is formed with an oil drain oil passage 90 for draining oil when the first rotor is advanced. The upstream end of the oil drain oil passage 90 opens at the end face of the valve body 77 located in the central hole 74, and the downstream end thereof is the same.
Has an opening on the outer peripheral surface thereof. Both the upper and lower openings are the valve body 7
It is always open regardless of position 7.

A supply passage 83 for the hydraulic oil 71 is formed in the valve body 77, the chain cover 75 and the like. Supply passage 83
The upstream end of the is connected to an oil pan 64 via an oil pump 63. The valve body 77 of the supply passage 83
The downstream portion of the valve extends radially and opens at the outer peripheral surface of the valve body 77. The opening 83a, as shown in FIG.
When the valve body 77 moves to the camshaft 23 side with the energization (ON) of the electromagnetic coil 80, the stepped portion 36 of the cover 36
matches a. By this matching, the supply passage 83 and the retard angle side hydraulic chamber 72a are communicated with each other through the opening 83a, the step portion 36a and the passage 73a, and the hydraulic oil 71 is supplied to the hydraulic chamber as indicated by a solid arrow in FIG. 72a.
At this time, the opening 83a, the step portion 36a, and the passage 73a function as a supply passage. Further, at this time, as shown by the broken line arrow in FIG. 8, the hydraulic oil 71 in the advance side hydraulic chamber 72b flows into the central hole portion 74 through the passage 73b and then passes through the oil drain oil passage 90. And is discharged to the outside of the housing 40. The hydraulic oil 71 is supplied to the retard side hydraulic chamber 72a and the hydraulic oil 71 from the advance side hydraulic chamber 72b.
The first rotor 41 rotates in the retard direction due to the discharge of.

On the other hand, as shown in FIG. 9, the opening 83a has a stepped portion 36 when the valve body 77 moves toward the electromagnetic coil 80 when the energization of the electromagnetic coil 80 is stopped (OFF).
Remove from a. A part of the opening 83a is connected to the step portion 36a, but a part thereof is opened to the outside of the housing 40. Therefore, the hydraulic oil 71 in the retard side hydraulic chamber 72a is
In the figure, as indicated by the solid arrow, it is discharged to the outside of the housing 40 through the passage 73a, the step portion 36a, and the opening 83a in order. At this time, the passage 73a and the step portion 36a
And the opening 83a functions as a discharge passage (drain passage). In addition, at this time, the air in the central hole 74 is
As indicated by a dashed arrow in FIG. 6, the gas flows into the advance side hydraulic chamber 72b through the passage 73b. The hydraulic oil 71 is discharged from the retard side hydraulic chamber 72a and the advance side hydraulic chamber 72
The first rotor 41 rotates in the advance direction due to the inflow of air into b.

Thus, the passage 73a, the step portion 36a,
A discharge passage that connects the inside and the outside of the housing 40 is configured by the opening 83a and the like. Further, the valve body 77, the spring 78, the solenoid valve 81, the bearing 82, and the like constitute an opening / closing valve 70 that opens only when the engine 11 is stopped. Further, the drain passage, the on-off valve, and the like constitute a first drain mechanism that drains the hydraulic oil 71 in the housing 40 when the engine 11 is stopped.

As shown in FIG. 2, an oil is provided in the middle of the supply passage 83 as a means for adjusting the hydraulic pressure of the hydraulic oil 71 acting on the projection 45 of the first housing 44 from the retard side hydraulic chamber 72a. Switching valve (OSV) 84
Is provided. The OSV 84 is an electromagnetically driven on-off valve, and based on the operating state of the engine 11, the ECU 62
Controlled by. By this control, the OSV 84 closes the supply passage 83, for example, during normal operation or stop of the engine 11, and opens the supply passage 83 during warm idle or the like. By opening the supply passage 83, the retard angle side hydraulic chamber 72
The hydraulic oil 71 is supplied to a, and the supply of the hydraulic oil 71 is stopped by closing the supply passage 83.

Then, the OSV 84 opens and closes the supply passage 83, and the reciprocating movement of the valve body 77 causes the discharge passage (opening 83).
The hydraulic pressure of the hydraulic oil 71 acting on the protrusion 45 of the first housing 44 is adjusted according to the opening / closing of a), and the housing 40 is
Rotate relative to the first rotor 41.

Further, the torsion coil spring 86 is used as an urging means for elastically urging the first housing 44 in a direction (advancing direction) for changing from the "latest phase" to the "most advanced phase". There is. The torsion coil spring 86 is arranged in the central hole 74, one end of which is locked to the first rotor 41 and the other end of which is locked to the plate 46. As the torsion coil spring 86, one having a spring force large enough to overcome the rotational torque of the camshaft 23 even when the rotational torque of the camshaft 23 becomes the largest as the engine rotational speed decreases. ing.

As described above, the relative rotation of the housing 40 is restricted by the at least one protrusion 45 contacting the front and rear vanes 43 in the rotational direction of the cam shaft 23. Among these, the vane 43 on the front side in the rotation direction of the cam shaft 23 functions as a rotation restricting means that restricts the housing 40 from further rotating in the advance direction.

The basic skeleton of the valve timing varying device 34 is constructed as described above. This variable device 34
According to the above, the rotation of the crankshaft 17 depends on the first rotor 41,
It is transmitted to the intake valve 21 via the housing 40, the hydraulic oil 71, the second rotor 51, the cam shaft 23, and the like. By this transmission, the intake valve 21 opens and closes at a predetermined operation timing (valve timing). This valve timing is
The housing 40 rotates relative to the first rotor 41, the second rotor 51 rotates relative to the housing 40, and the cam shaft 23 rotates relative to the crank shaft 17 to change within a predetermined range. To be done. In other words, the range in which the rotation phase of the housing 40 with respect to the first rotor 41 and the rotation phase of the second rotor 51 with respect to the housing 40 are combined, that is, the relative rotation that the second rotor 51 can have with respect to the first rotor 41. The rotation range is the “predetermined range”, and the rotation phase of the cam shaft 23 is changed within this predetermined range.

The relative rotation of the housing 40 depends on the operating oil 71.
And the elastic biasing force in the advance direction by the torsion coil spring 86. However, in the first rotor 41, the vane 4 on the front side in the rotation direction of the cam shaft 23
Since 3 functions as a rotation restricting means, relative rotation of the housing 40 is restricted by the protrusion 45 of the housing 40 coming into contact with the vane 43. Further, the relative rotation of the second rotor is caused by the operating oil 7 supplied through the oil passages 56, 57 and the like.
It is performed based on the hydraulic pressure of 1, the rotational torque of the cam shaft 23, and the like.

The movable range, which is the range that the second rotor 51 can actually take, changes depending on the rotation phase of the housing 40 with respect to the first rotor 41. Housing 40
When the rotation phase of is the "latest phase", the movable range of the second rotor 51 is maximum, that is, the predetermined range ("the most retarded phase" to "the most advanced phase"). Housing 40
However, when the relative rotation occurs within the range from the “latest phase” to immediately before the rotational phase regulated by the vane 43, the movable range of the second rotor 51 is from the rotational phase of the housing 40 at that time. It is limited to the range up to "the most advanced phase". On the other hand, when the relative rotation of the housing 40 in the advance direction is restricted by the vanes 43,
The movable range of the second rotor 51 is, of the predetermined range,
It is limited to the range from the “middle phase” to the “advanced phase”, which is advanced from the “latest phase”. Here, from the viewpoint of the rotational phase with respect to the crankshaft 17, the “most advanced phase” of the housing 40 and the “intermediate phase” of the camshaft 23 are the same.

The second rotor 51 may or may not be affected by the elastic biasing force of the torsion coil spring 86 depending on the rotational phase of the housing 40. When the rotation phase of the housing 40 is within the range not controlled by the vanes 43 (“latest phase” to “most advanced phase”),
When the second rotor 51 becomes the slowest one in its movable range, the housing 40 and the second rotor 51 are separated from each other by the camshaft 2
3 is in a connected state so that power can be transmitted in the rotation direction. Therefore, the elastic biasing force of the torsion coil spring 86 applied to the housing 40 is also transmitted to the second rotor 51 via the housing 40.

On the other hand, when the relative rotation of the housing 40 in the advance direction is restricted by the vanes 43, the second rotor 51 is not affected by the elastic biasing force. This is because the rotation of the vanes 43 prevents the housing 40 from rotating relative to the advance angle any more, the connection state in the rotation direction is released, and the power transmission from the housing 40 to the second rotor 51 is performed. Because it is blocked.

Therefore, the housing 40 and the second rotor 5
The rotational phase of the camshaft 23 can be variously changed by adjusting the hydraulic pressure of the hydraulic oil 71 added to the hydraulic pressure 1 according to the operating state (including stop) of the engine 11.

The variable valve timing device 34 further includes a first lock mechanism 87 and a second lock mechanism 95. The first lock mechanism 87 is a mechanism for connecting the first housing 44, whose relative rotation in the advance direction is restricted by the vanes 43, to the first rotor 41 such that the first housing 41 cannot rotate relative to the first rotor 41. The mechanism 87 will be described. As shown in FIG. 10, a predetermined vane 43 of the first rotor 41 has a stepped accommodating hole 88 formed in parallel with the cam shaft 23. The lock pin 89 is slidably inserted. The first lock pin 89 is always elastically biased toward the plate 46 by the spring 91. On the other hand, a lock hole 92 is formed in the plate 46 at a position corresponding to the accommodation hole 88.
When 8 is matched, the tip of the first lock pin 89 elastically biased by the spring 91 is inserted. The accommodation hole 8
The position corresponding to 8 corresponds to the accommodation hole 88 when the relative rotation of the first housing 44 in the advance direction is restricted by the vane 43.

In the accommodation hole 88, the first lock pin 8
The space between the flange 89a of the No. 9 and the step 88a of the accommodation hole 88 communicates with the retard angle side hydraulic chamber 72a via the passage 93, and the hydraulic oil 71 is supplied from the hydraulic chamber 72a. The bottom of the lock hole 92 communicates with the retard angle side hydraulic chamber 72a via a passage 94, and the hydraulic oil 71 is supplied from the hydraulic chamber 72a.

In the first lock mechanism 87 having the above-described structure, the retard side hydraulic chamber 72a is used when the engine 11 is idle or the like.
When the hydraulic oil 71 is supplied to the first lock pin 89, the first lock pin 89 is pulled out from the lock hole 92 against the spring 91 by the hydraulic pressure of the hydraulic oil 71 from the hydraulic chamber 72a. The lock is released, and the housing 40 can rotate relative to the first rotor 41.

When the engine 11 is stopped, etc.
When the supply of the hydraulic oil 71 to the retard angle side hydraulic chamber 72a is stopped and the hydraulic pressure decreases, the first lock pin 89 tries to protrude from the accommodation hole 88 by the spring 91. At this time, if the lock hole 92 is aligned with the housing hole 88, the first lock pin 89 projects from the housing hole 88 and is inserted into the lock hole 92, and the housing 40 is connected (locked) to the first rotor 41.
And is held at the "most advanced phase".

The second lock mechanism 95 is a mechanism for connecting the second rotor 51 to the housing 40 so that they cannot rotate relative to each other when the cam shaft 23 is in the intermediate phase. This mechanism 9
5 has the same configuration as the first lock mechanism 87 described above. As shown in FIG. 11, a stepped accommodating hole 96 is formed in the predetermined vane 53 of the second rotor 51 in parallel with the cam shaft 23, and the second lock pin 97 with a flange is slidable therein. Has been inserted into. Second lock pin 97
Is constantly elastically urged toward the sprocket 25 by a spring 98. On the other hand, a lock hole 99 is formed in the bottom portion of the case body 35 at a position corresponding to the housing hole 96, and when the housing hole 96 is aligned with the lock hole 99 due to the relative rotation of the second rotor 51, the spring 98 is used. The tip end of the elastically biased second lock pin 97 is inserted. The location corresponding to the accommodation hole 96 is the location that matches the accommodation hole 96 when the rotational phase of the cam shaft 23 becomes the intermediate phase.

In the accommodation hole 96, the second lock pin 9
A space between the flange 97 a of the No. 7 and the step 96 a of the accommodation hole 96 communicates with the retard angle side hydraulic chamber 54 via the passage 101, and the hydraulic oil 71 is supplied from the hydraulic chamber 54. Further, the bottom portion of the lock hole 99 communicates with the advance side hydraulic chamber 55 via the passage 102, and the hydraulic oil 71 flows from the hydraulic chamber 55 to the advance side hydraulic chamber 55.
Is supplied.

In the second lock mechanism 95 having the above structure, when the engine 11 is in operation and the hydraulic oil 71 is supplied to at least one of the retard side hydraulic chamber 54 and the advance side hydraulic chamber 55, The hydraulic pressure causes the second lock pin 97 to be pulled out from the lock hole 99 against the spring 98. The lock is released, and the second rotor 51 can rotate relative to the housing 40.

Further, when the engine 11 is stopped and the supply of the hydraulic oil 71 to the retard side hydraulic chamber 54 and the advance side hydraulic chamber 55 is stopped and the hydraulic pressure decreases, the second lock pin 9
7 tries to protrude from the accommodation hole 96 by the spring 98. At this time, if the accommodation hole 96 is aligned with the lock hole 99, the second lock pin 97 projects from the accommodation hole 96 and is inserted into the lock hole 99, and the second rotor 51 is connected to the housing 40 via the case 37 ( Locked). The second rotor 51 cannot rotate relative to the housing 40, and the rotational phase of the cam shaft 23 is maintained at the intermediate phase.

Next, the valve timing changing device 34 is used.
The operation of will be described for each operating state of the engine 11. Figure 1
2 and FIG. 13 show the states of the housing 40 and the rotors 41 and 51 when the engine 11 is warmly idle. At this time, the supply passage 83 is opened by energizing the OSV 84, the valve body 77 is moved to the position shown in FIG. 8 by energizing the solenoid valve 81, and the opening 83a is aligned with the step portion 36a. The supply passage 83 is in communication with the step portion 36a and the passage 73a through the opening 83a. The opening 83a, the step portion 36a, and the passage 73a function as a supply passage.

As shown by the solid arrows in FIG.
The hydraulic oil 71 is supplied into the retard angle side hydraulic chamber 72a through the supply passage 83 (including the opening 83a), the step portion 36a and the passage 73a. The hydraulic oil 71 in the advance side hydraulic chamber 72b is
As shown by the broken line arrow in FIG. 8, after flowing into the central hole portion 74 through the passage 73b, it passes through the oil drain oil passage 90 and exits to the outside of the housing 40. On the other hand, in the second housing 47, the retard side hydraulic chamber 54 is more than the advance side hydraulic chamber 55.
The OCV 58 is controlled so that the internal hydraulic pressure is increased. In the lock mechanisms 87 and 95, the first lock pin 89 and the second lock pin 89
The lock pin 97 is pulled out from the lock holes 92 and 99, and the lock is released.

Therefore, the housing 40 rotates in the retard direction against the torsion coil spring 86. This rotation is stopped when at least one protrusion 45 of the first housing 44 contacts the vane 43 of the first rotor 41.
The projection 49 of the housing 40 rotates in the retard direction as the housing 40 rotates.
Rotates in the same direction following the rotation of. This rotation is the second
At least one of the vanes 53 of the rotor 51 comes into contact with the protrusion 49 of the second housing 47 to stop. As a result, the rotational phase of the camshaft 23 with respect to the crankshaft 17 is the most delayed (the most retarded phase). In the most retarded phase,
The operation timing of the intake valve 21 is the latest with respect to the rotation of the crankshaft 17.

14 and 15 show the states of the housing 40 and the rotors 41 and 51 during normal operation of the engine 11. At this time, the supply passage 83 is closed by stopping the energization of the OSV 84, and the solenoid valve 8
The valve body 77 is moved to the position shown in FIG. 8 by the energization of No. 1, and the opening 83a is formed in the step portion 36 in the same manner as in the warm idle.
matches a. The retard angle side hydraulic chamber 72 of the first housing 44
The hydraulic oil 71 is not supplied to a. On the other hand, in the second housing 47, the supply / discharge of the hydraulic oil 71 to the retard side hydraulic chamber 54 and the advance side hydraulic chamber 55 is adjusted by the duty control of the OCV 58.

In the process in which the housing 40 elastically biased by the torsion coil spring 86 relatively rotates in the advance direction, the accommodation hole 88 of the first lock mechanism 87 is aligned with the lock hole 92. The first lock pin 89 enters the lock hole 92, and the housing 40 is connected (locked) to the first rotor 41.
Thus, the rotational phase of the housing 40 is kept at the “most advanced phase”.

In the second rotor 51, the relative rotation to the retard side relative to the intermediate phase is regulated, but the relative rotation to the advance side is not restricted. Therefore, due to the relative rotation of the second rotor 51, the rotational phase of the camshaft 23 with respect to the crankshaft 17 is in the range of the intermediate phase slightly advanced from the most retarded phase and the most advanced state (most advanced phase). It can be changed arbitrarily.

In the most advanced phase, the operation timing of the intake valve 21 becomes earliest with respect to the rotation of the crankshaft 17. Further, the rotation phase of the cam shaft 23 with respect to the crank shaft 17 can be changed within the range from the intermediate phase to the most advanced angle phase, and the operation timing of the intake valve 21 can be set to an arbitrary timing.

FIGS. 16 and 17 show the states of the housing 40 and the rotors 41, 51 when an operation for stopping the engine such as turning off the ignition key is performed (when the engine is stopped). There is. At this time, the supply passage 83 is closed by stopping the energization of the OSV 84, the valve body 77 is moved to the position shown in FIG. 9 by stopping the energization of the solenoid valve 81, and the opening 83a is disengaged from the step portion 36a. The step portion 36a and the passage 73a are connected to the outside of the housing 40 through the opening 83a.
The opening 83a, the step portion 36a, and the passage 73a function as a discharge passage. Air in the central hole 74 can flow into the advance side hydraulic chamber 72b through the passage 73b.

Since the working oil 71 is not supplied to the first housing 44, the working oil 71 in the retard angle side hydraulic chamber 72a is supplied to the passage 73a and the step portion 36 as shown by the solid arrow in FIG.
It is discharged to the outside of the housing 40 through a and the opening 83a. Further, when the OCV 58 is de-energized, the retard side oil passage 56 and the advance side oil passage 57 respectively communicate with the discharge passage 61, and in the second housing 47, the inside of the retard side hydraulic chamber 54 and the advance side hydraulic chamber 55. The hydraulic oil 71 inside is discharged together.

Rotation torque due to the cam of the cam shaft 23 is applied to the second rotor 51, and this rotation torque increases as the engine speed decreases, but the spring of the torsion coil spring 86 that has been stored under pressure is applied. The force overcomes this rotational torque, and the housing 40 relatively rotates toward the advance side. In the process of this relative rotation, the accommodation hole 88 is locked by the lock hole 92.
And the first lock pin 89 enters the lock hole 92. The housing 40 is coupled (locked) to the first rotor 41 so that it cannot rotate relative to the first rotor 41, and the rotational phase of the housing 40 is held at the “most advanced phase”. In addition, the second rotor 5
The accommodation hole 96 is aligned with the lock hole 99 and the second lock pin 97 is inserted into the lock hole 99 during the relative rotation of the device 1.
The second rotor 51 is connected (locked) to the case 37, and the rotational phase of the cam shaft 23 is maintained at the intermediate phase.

As described above in detail, in the present embodiment, the conventional rotor and housing combination is divided into the first rotor 41 and the housing 4 by dividing the rotor into two.
It is changed to a combination of 0 and the second rotor 51. From this, the following various effects can be obtained.

(1) A torsion coil spring 86 having a large spring force is used as the biasing means. Therefore, the camshaft 2
The housing 40 can be relatively rotated in the advance direction against the rotation torque of No. 3, and the rotation phase can be changed to the "most advanced phase". The rotation phase of the cam shaft 23 is set to the housing 4
In the movable range limited by 0, it can be set to the intermediate phase which is the slowest rotation phase. In this way, the rotation phase of the cam shaft 23 can be surely set to the intermediate phase by the time the engine 11 is started. Therefore, when the engine is started, it is possible to perform a stable start in an intermediate phase, and an effect of reducing exhaust emissions of HC and the like at the time of starting can be expected.

(2) Crankshaft 17 during warm idling
Of the hydraulic oil 71 decreases, and the hydraulic pressure of the hydraulic oil 71 decreases.
In the relative rotation of the housing 40 to the "latest phase", a force of a magnitude that overcomes the elastic biasing force of the torsion coil spring 86 is required.

On the other hand, in this embodiment, the number of protrusions 45 is increased and the pressure receiving area of the first housing 44 is increased. Therefore, the torsion coil spring 86 having a large spring force
Despite using, the force of a magnitude that overcomes it is generated to change the rotational phase of the housing 40 to the “latest phase”, and the rotational phase of the camshaft 23 is surely set to the most retarded angle phase. be able to. By setting the most retarded phase in this way, it is possible to stabilize combustion during idle operation and improve fuel efficiency.

(3) During normal operation of the engine 11, the supply of the hydraulic oil 71 to the retard angle side hydraulic chamber 72a is stopped by stopping the energization of the OSV 84 and closing the supply passage 83. By this stop, the spring force of the torsion coil spring 86 is released, and the first housing 44 relatively rotates in the advance direction. Therefore, the rotational phase of the cam shaft 23 can be arbitrarily changed from the intermediate phase to the most advanced angle phase by adjusting the hydraulic pressure acting on the vanes 53 and relatively rotating the second rotor 51. Intake valve 21
Can be opened and closed at a valve timing suitable for the operating state.

(4) First rotor 41 and housing 40
By providing the torsion coil spring 86 therebetween, the spring force is directly applied to the housing 40 and is indirectly transmitted to the second rotor 51. Therefore, regarding the second rotor 51 and the second housing 47, the first
Unlike the rotor 41 and the first housing 44, it is not necessary to increase the number of the vanes 53 and the protrusions 49 to increase the pressure receiving area. Therefore, it is possible to suppress the adverse effect caused by increasing the pressure receiving area, that is, the second rotor 51 can be prevented from reacting excessively to the pressure change of the hydraulic oil 71 during the normal operation. It becomes easy to control the cam shaft 23 to a desired rotation phase, and control accuracy is improved.

Further, according to this embodiment, the above (1)
In addition to (4), the following effects are also obtained. (5) The first lock mechanism 87 is provided between the housing 40 and the first rotor 41. Therefore, for example, the engine 1
When the hydraulic pressure of the hydraulic oil 71 is reduced with the stop of No. 1, the spring force of the torsion coil spring 86 is released, and the rotation phase of the housing 40 is changed to the "most advanced phase", the housing 40 is locked by the first lock. The mechanism 87 is connected to the first rotor 41 so as not to rotate relative to it. That is, the rotation phase of the housing 40 is maintained at the “most advanced phase”, and the movable range of the relative rotation of the second rotor 51 is reliably limited. Therefore, the relative rotation of the second rotor 51 toward the retard side allows the rotational phase of the cam shaft 23 to be held at the intermediate phase.

Further, when the hydraulic pressure of the hydraulic oil 71 acting on the protrusion 45 is lowered by stopping the energization of the OSV 84 during the normal operation of the engine 11, for example, in this case as well, the housing 40 of the housing 40 is subjected to the same operation. The rotation phase is changed to the “most advanced phase” and is connected to the first rotor 41 by the first lock mechanism 87. Therefore, the housing 40
Can be held at the "most advanced phase", the movable range of the relative rotation of the second rotor 51 can be limited, and the rotation phase of the cam shaft 23 can be prevented from becoming slower than the intermediate phase.

(6) A second lock mechanism 95 is provided between the second rotor 51 and the case 37. Therefore, when the engine 11 is stopped, the housing 40 is locked by the first lock mechanism 87 and the rotational phase is not only held at the "most advanced phase" but also to the retard side of the second rotor 51. When the rotational phase of the cam shaft 23 becomes the intermediate phase due to the relative rotation of the second rotor 51, the second rotor 51 is locked by the second lock mechanism 95. Therefore, by locking the housing 40 and the second rotor 51, the camshaft 23 can be held in an intermediate phase suitable for starting while the engine 11 is stopped.

(7) If at least one of the housing 40 and the second rotor 51 is not locked by the lock mechanism 87, 95 when the engine 11 is stopped, it is necessary to lock it at the next start. However, when the engine 11 is started at an extremely low temperature, the viscosity of the hydraulic oil 71 is high, and the hydraulic oil 71 is not contained in the housing 40 or the second rotor 51.
May interfere with the movement of.

On the other hand, in this embodiment, the valve timing varying device 34 is provided with the first drain mechanism and the second drain mechanism. Therefore, when the engine 11 is stopped, the hydraulic oil 71 in the first housing 44 is discharged by the first drain mechanism and the hydraulic oil in the second housing 47 is discharged by the second drain mechanism when the engine 11 is stopped. . Therefore, even if the engine is started at an extremely low temperature as described above, the amount of the hydraulic oil 71 in both the housings 44 and 47 that hinders the movement of the first housing 44 and the second rotor 51 is small. Therefore, even if the locking by the lock mechanisms 87 and 95 is not properly performed due to the stop of the engine 11, the housing 40 and the second rotor 51 are relatively rotated at the time of starting, so that the rotation phase of the cam shaft 23 becomes the intermediate phase. can do.

Particularly, immediately after the engine 11 is stopped, the temperature of the hydraulic oil 71 is high and the viscosity thereof is low, so that the hydraulic oil 71 can be smoothly discharged. (8) The torsion coil spring 86 is used as the biasing means. Therefore, a large elastic biasing force can be easily obtained as compared with the case where another type of spring is used as the biasing means.

The present invention can be embodied in another embodiment shown below. The torsion coil spring 86 may be locked to the case 37 at one end and to the housing 40 at the other end. Therefore, unlike the above-described embodiment, the case 37 may be locked to a position other than the first rotor 41 or the housing 40 to a position other than the plate 46.

The valve timing varying device of the present invention may be applied to the exhaust side cam shaft 24 to change the operation timing of the exhaust valve. The variable valve timing device may be applied to both the intake side cam shaft 23 and the exhaust side cam shaft 24.

As the biasing means, a spring of a type different from the torsion coil spring may be used, or an elastic member other than the spring may be used. Further, a mechanism utilizing an elastic biasing force such as a spring may be adopted as the biasing means. What is essential is that the first rotor 41 is elastically biased toward the advance side.

Other technical ideas that can be understood from the above-described embodiments will be described together with their effects. (A) In the valve timing varying device for an internal combustion engine according to any one of claims 1 to 5, the urging means includes:
The torsion coil spring has one end locked to the first rotor and the other end locked to the housing.

According to the above construction, a large elastic biasing force can be easily obtained as compared with the case where another type of spring is used as the biasing means.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an engine equipped with a valve timing varying device of the present invention.

FIG. 2 is a cross-sectional view showing a valve timing variable device and a hydraulic oil supply structure to the device.

3 is an enlarged sectional view taken along line 3-3 of FIG.

FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG.

FIG. 5 is a partial cross-sectional view showing an operation mode of OCV.

FIG. 6 is a partial sectional view showing an operating mode of the OCV.

FIG. 7 is a partial sectional view showing an operating mode of the OCV.

FIG. 8 is a partial cross-sectional view showing an operation mode of a first drain mechanism in the variable valve timing device.

FIG. 9 is also a first example of a valve timing varying device.
FIG. 6 is a partial cross-sectional view showing an operation mode of the drain mechanism.

10 is an enlarged sectional view taken along line 10-10 of FIG.

11 is an enlarged sectional view taken along line 11-11 of FIG.

FIG. 12 is a partial enlarged cross-sectional view corresponding to FIG. 3, showing an operation mode of the first housing at the time of warm idling of the engine.

FIG. 13 is a partial enlarged cross-sectional view corresponding to FIG. 4, showing an operation mode of the second rotor during warm idling of the engine.

FIG. 14 is a partial enlarged cross-sectional view corresponding to FIG. 3, showing an operating mode of the first housing during normal operation of the engine.

FIG. 15 is a partial enlarged cross-sectional view corresponding to FIG. 4, showing an operation mode of the second rotor during normal operation of the engine.

16 is a partial enlarged cross-sectional view corresponding to FIG. 3, showing an operation mode of the first housing when the engine is stopped.

FIG. 17 is a partial enlarged cross-sectional view corresponding to FIG. 4, showing an operating mode of the second rotor when the engine is stopped.

[Explanation of Codes] 11 ... Engine, 17 ... Crankshaft, 21 ... Intake valve, 23 ... Camshaft, 34 ... Valve timing variable device,
40 ... Housing, 41 ... First rotor, 43 ... Vane,
51 ... Second rotor, 56 ... Retardation side oil passage, 57 ... Advancement side oil passage, 70 ... Open / close valve, 71 ... Hydraulic oil, 83 ... Supply passage, 8
4 ... OSV, 86 ... Torsion coil spring, 87 ... 1st locking mechanism, 95 ... 2nd locking mechanism.

Continued front page    (72) Inventor Yoshikazu Ishii             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. (72) Inventor Mutsumi Nishimura             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F-term (reference) 3G018 AA01 AB07 AB17 BA33 CA20                       DA24 DA49 DA57 DA58 DA72                       DA73 DA74 EA01 EA21 EA31                       EA32 EA33 FA01 FA07 GA02                       GA07 GA09                 3G092 AA01 AA05 AA11 AB02 DA01                       DA02 DA10 DG05 DG09 EA03                       EA04 EA13 EA28 EA29 FA06                       FA18 FA24 GA01 GA10

Claims (5)

[Claims] 1. A first rotor which is drivingly connected to a crankshaft of an internal combustion engine and which rotates relative to a valve driving camshaft, and a pressure of a working fluid of the internal combustion engine supplied through a predetermined passage, A housing that rotates relative to one rotor; and a housing that is integrally rotatably attached to the cam shaft in a state of being arranged in the housing, and is based on the pressure of the working fluid supplied through a passage different from the predetermined passage. A second rotation mechanism that changes the rotation phase of the cam shaft with respect to the crank shaft within a predetermined range by rotating relative to the housing.
A rotor, an urging means for elastically urging the housing in an advance direction, and a relative rotation of the housing in the advance direction when the rotational phase of the cam shaft reaches an intermediate phase within the predetermined range. A valve timing varying device for an internal combustion engine, comprising: 2. The valve timing varying device for an internal combustion engine according to claim 1, further comprising a first lock mechanism that connects the housing, the relative rotation of which is restricted by the rotation restricting means, to the first rotor so that the housing cannot rotate relative to the first rotor. . 3. The housing is connected to the first rotor by the first locking mechanism when the internal combustion engine is stopped, and the rotational phase of the cam shaft becomes the intermediate phase due to relative rotation of the second rotor. The valve timing varying device for an internal combustion engine according to claim 2, further comprising a second lock mechanism that connects the second rotor to the housing such that the second rotor cannot rotate relative to the housing. 4. A hydraulic fluid, the viscosity of which changes with temperature, is used as the hydraulic fluid, and a drain mechanism is provided for discharging the hydraulic fluid in the housing when the internal combustion engine is stopped. The variable valve timing device for an internal combustion engine according to claim 2 or 3, 5. The drain mechanism according to claim 4, further comprising an exhaust passage communicating the inside and the outside of the housing with each other, and an opening / closing valve provided midway in the exhaust passage and opened only when the internal combustion engine is stopped. A variable valve timing device for an internal combustion engine as described above.