JP2001132416A - Valve opening/closing timing control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set phase change response to the advance angle side and the delay angle side to be roughly similar at the phase change in a valve opening/closing timing control device. SOLUTION: Total of an acting surface of operating fluid supplied to an advance angle chamber 76 on a vane 44 is set to be larger than an acting surface of operating fluid supplied to a delay angle chamber 78 on the vane 44 for setting acting force to the advance angle side larger, thereby force on the delay angle side acting on a can shaft for opening/closing gas discharge/intake valves is offset.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control apparatus for an internal combustion engine.

[0002]

2. Description of the Related Art Hitherto, a number of valve timing control devices for controlling the timing between a timing pulley and a camshaft have been introduced. One type of the valve timing control device is disclosed in US Pat. No. 5,870,983. A type of valve timing control device is known.

The valve timing control devices disclosed in these publications include a camshaft that opens and closes an intake valve or an exhaust valve by rotating in a predetermined direction, and a housing that is rotatably mounted on the outer periphery of the camshaft. A plurality of hydraulic chambers formed between the camshaft and the housing, and an advance chamber and a rotational phase of the camshaft with respect to the housing which are attached to the camshaft and which advance the rotational phase of each of the hydraulic chambers with respect to the housing of the camshaft. A plurality of vanes partitioned into a retard chamber for delaying the hydraulic pressure, an advance hydraulic passage for increasing and decreasing the hydraulic pressure of the advance chamber, a retard hydraulic passage for increasing and decreasing the hydraulic pressure of the retard chamber, an advance hydraulic passage and a retard hydraulic pressure And hydraulic control means for controlling the hydraulic pressure in the passage.

In the valve timing control apparatus having the above-described structure, the vane is moved in the hydraulic chamber by providing a difference in oil pressure between the advance chamber and the retard chamber divided by the vane in the hydraulic chamber. When the vane moves, the camshaft to which the vane is attached also moves integrally, so that the camshaft and the housing relatively rotate to generate a phase difference. The valve opening / closing timing control device advances or retards the rotation of the camshaft with respect to the rotation of the housing rotated by the driving force of the engine by generating this phase difference, and the intake valve that opens and closes by opening and closing the camshaft. Alternatively, the opening / closing timing of the exhaust valve is changed.

However, the driving energy applied to the camshaft for opening and closing the exhaust or intake valve causes
The camshaft as the driven shaft receives a force on the retard side with respect to the drive shaft. Therefore, during driving of the engine, the camshaft is always urged to the retard side. This means that when the vane, which can move within the range of the radial length of the hydraulic chamber, is located at an intermediate position of the moving range, the vane is advanced by adjusting the hydraulic pressure of the advance chamber and the hydraulic pressure of the retard chamber. To rotate the vane to the side, a high oil pressure is required on the advance chamber side, whereas when rotating the vane to the retard side, it can be achieved by supplying a relatively small oil pressure to the retard chamber side. . In other words, in order to rotate the vane to the advance side, it is necessary to supply hydraulic pressure to the advance chamber side to rotate the camshaft against the force for urging the camshaft to the retard side. The response to advance the intake valve or exhaust valve by the device,
This delays the response much longer than the response of retarding, which causes a problem that the desired output performance of the engine cannot be obtained.

[0006]

In the invention disclosed in the above prior art, a coil spring is arranged between a vane attached to a camshaft and a housing, and the coil spring is provided with the above-mentioned prior art. The solution is achieved by urging the vane (camshaft) to the advanced side. However, the hydraulic pressures of the advance chamber and the retard chamber during the rotation of the engine greatly change depending on the number of revolutions of the engine. The range of force fluctuation is greatly different from that of the coil spring that urges the (camshaft) to the advanced side. In other words, when arranging the coil sprue, it is very difficult to select a spring constant for determining the urging force of the coil spring.

Therefore, the present invention provides a valve timing control apparatus which solves the above-mentioned technical problems of the prior art.

[0008]

The technical measures taken to solve the above-mentioned problems include a camshaft that opens and closes an intake valve or an exhaust valve by rotating in a predetermined direction, and a relative rotation around an outer periphery of the camshaft. A housing that can be mounted, a plurality of hydraulic chambers formed between the camshaft and the housing, and an advance chamber and a camshaft that are mounted on the camshaft and advance the rotational phase of each of the hydraulic chambers with respect to the housing. A plurality of vanes partitioned into a retard chamber that delays the rotation phase of the housing, an advance hydraulic passage that increases and decreases the hydraulic pressure of the advance chamber, a retard hydraulic passage that increases and decreases the hydraulic pressure of the retard chamber, and an advance hydraulic In the valve timing control apparatus including the passage and the hydraulic pressure control means for controlling the hydraulic pressure of the retard hydraulic passage, the total area of the advance chamber acting on the vane acts on the vane. It is obtained by a greatly configuration than the total area of the hydraulic chamber.

According to the above-described means, the total area of the retard chamber for urging the vane is smaller than the total area of the advance chamber for urging the vane. Can be provided. Due to this difference in the pressure receiving area, when the vane attached to the camshaft is relatively rotated with respect to the housing, the urging force of the hydraulic pressure to the advance side can be increased, and the rotation to the advance side and the retard angle The response to the rotation to the side can be substantially the same. Further, by providing a difference in the pressure receiving area of the vane, even if the hydraulic pressure of the advance chamber and the retard chamber changes due to the operating condition of the engine, the change in the hydraulic pressure causes the relative rotation to the advance side and the retard side. The response can be kept constant.

Further, in the above invention, it is preferable that the retard hydraulic passage communicates with only some of the plurality of retard chambers.

Further, in the above invention, it is preferable that the hydraulic control means comprises two on / off valves for controlling only the hydraulic pressure of the advance chamber.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A valve timing control apparatus according to the present invention will be described below with reference to the drawings.

A valve timing control apparatus according to a first embodiment of the present invention shown in FIGS. 1 to 3 comprises a camshaft 12 rotatably supported by a cylinder head 10 of an internal combustion engine,
The camshaft 12 has a rotating shaft composed of an internal rotor 16 integrally attached to a tip end portion of the camshaft 12 with bolts 14. This valve opening / closing timing control device includes an outer rotor 20 externally mounted on the inner rotor 16 so as to be relatively rotatable within a predetermined range and having a timing sprocket 18 on an outer peripheral portion.
The front plate 22 and the rear plate 24 also have a rotation transmitting member integrally fixed by bolts (not shown). As shown in FIG. 2, bolt holes 25 to 29 through which the bolts are formed are formed in the outer rotor 20 at positions indicated by reference numerals 25 to 29 at substantially equal intervals in an annular shape. Further, bolt holes (not shown) are formed at positions corresponding to the positions of the bolt holes 25 to 29 of the front plate 22 and the rear plate 24. As shown in FIG. 1, the driving force of the internal combustion engine is transmitted to the timing sprocket 18 from the crankshaft 30 via the timing chain 32 to the rotation transmission member, and the rotation transmission member is a clock indicated by an arrow in FIGS. 2 and 3. Rotate in the direction of rotation. A shunt hole 34 extending in the radial direction is cut in the external rotor 20, and a lock pin 36, a lock pin 3
A spring 38 for urging the valve 6 and a lid 40 for closing the outer edge of the escape hole 34 are enclosed. The lock pin 36 is for maintaining a desired relative phase between the internal rotor 16 and the external rotor 20, and locks at the most retarded position shown in FIG. 2 in the present embodiment.

The inner rotor 16 has four radial grooves 42 formed therein, and each groove 42 has a vane 44.
The plate spring 45 urges and holds the vane 44 outward.

The camshaft 12 has a well-known cam for opening and closing an intake valve (not shown). The camshaft 12 and the internal rotor 16 have an advance passage 46 therein.
And a retard passage 48 are formed. The advance angle passage 46 and the retard angle passage 48 are respectively connected to the first port 52 and the second port 54 of the switching valve 50 through passages formed in the cylinder head.
Is in communication with

The switching valve 50 can move the spool 58 against the spring 60 by energizing the solenoid 56. When the energizing is not performed, the switching valve 50 is connected to an oil pump 62 driven by the internal combustion engine. The port 64 communicates with the first connection port 54, and the second connection port 52 communicates with the discharge port 66. In addition, when the power is supplied, the supply port 64 communicates with the second connection port 52, and the first connection port 54 communicates with the discharge port 66. Therefore, when the switching valve 50 is not energized, the working oil is supplied to the retard passage 48 and the hydraulic oil is discharged from the advance passage 46. When the switching valve 50 is energized, hydraulic oil is supplied to the advance passage 46 and hydraulic oil in the retard passage 48 is discharged. In the present embodiment, the first port 52 and the second port 54 are connected to the supply port 64 and the discharge port 6.
The spool 58 can be held at a position not connected to the spool 6.

The internal rotor 16 is fixed to the camshaft 12 by bolts 14 via spacers 68. In addition, in addition to the vane 44, the lock pin 36 is provided on the outer peripheral portion of the inner rotor 16 when the relative position between the rotation transmitting member and the camshaft 12 is at the most retarded phase (most retarded position) shown in FIG. An insertable receiving hole 70 is formed. A hydraulic passage 72 communicating between the receiving hole 70 and the advance passage 46 is formed in the internal rotor 16, and when hydraulic oil is supplied to the advance passage 46, the hydraulic oil is also supplied to the receiving hole 70. Is supplied. The spring constant of the spring 38 is determined by the hydraulic pressure of the operating oil supplied to the receiving hole 70.
6 is set to such a strength as to push it back into the escape hole 34.

The outer periphery of the outer rotor 20 has four notches in the circumferential direction, and four hydraulic chambers 74 are formed between the outer rotor 20 and the outer periphery of the inner rotor 16. Each hydraulic chamber 74 is partitioned by the vane 44 into an advance chamber 76 and a retard chamber 78. The vane 44 has a length corresponding to the circumferential length of the hydraulic chamber 74.
The vane 4 is rotatable relative to the external rotor 20.
4. Since the internal rotor 16 and the camshaft 12 are integrated, the relative phase between the external rotor 20 and the camshaft 12 can be changed. Here, FIG. 2 shows the most retarded position, and only the vane 44 disposed in the upper right hydraulic chamber 74 in FIG. 2 is in contact with the stopper 80 formed on the external rotor 20. FIG. 3 shows the most advanced position, and the vanes 4 arranged in the upper left hydraulic chamber 74 in FIG.
Only 4 is in contact with a stopper 82 formed on the outer rotor 20.

Of the four hydraulic chambers 74, only the retard chamber 78 of the hydraulic chamber 74 shown in the upper left of FIGS.
Are connected to each other, and the other retard chambers 78
Is not communicating. On the other hand, the advance passage 46 communicates with all four advance chambers 76. Accordingly, in the entire four hydraulic chambers 74, the hydraulic oil in the advance chamber 76 causes the vane 44 to move the vanes 44 in FIGS.
The area urged in the rotation direction of the clock at
The area within which the hydraulic oil urges the vane 44 in the counterclockwise direction of the clock in FIGS. 2 and 3 is four times as large. Also, 4
Of the individual retard chambers 78, each of the retard chambers 78 to which the retard passage 48 does not communicate (i.e., the upper right, lower right, and lower left retard chambers 78 in FIGS. 2 and 3) has a retard angle. A passage 84 communicating between the chamber 78 and the outside of the external rotor 20 is formed. As shown in FIG. 3, the passage 84 is located at the most advanced position,
4 Even if it is located on the most advanced side, it is cut to a position that does not become the advanced chamber 76. Therefore, in these three hydraulic chambers 74, even if the hydraulic oil in the advance chamber 76 flows into the retard chamber 78 beyond the sealing surface of the tip of the vane 44 with the external rotor 20, the hydraulic oil flows through the passage 84. Can be discharged to the outside through

The operation of the valve timing control apparatus according to the first embodiment having the above configuration will be described.

When the phase is changed from the most retarded position shown in FIG. 2 to the advanced side, the switching valve 50 is moved to the position shown in FIG. 1 (that is, the spool 58 is moved to the position where the solenoid 56 is energized). Then, the hydraulic oil pressurized by the pump 62 is supplied to the advance passage 46 and the hydraulic passage 72 branched from the advance passage 46, and the hydraulic oil in the retard passage 48 is discharged. Accordingly, the hydraulic oil is supplied to the four advance chambers 76 and the receiving holes 70, and the lock pins 3 inserted into the receiving holes 70.
6 is returned to the escape hole 34 against the urging force of the spring 38, and the hydraulic oil in the retard chamber 78 (the retard chamber 78 located at the upper left of FIGS. 2 and 3) filled with hydraulic oil is discharged. Is done. The camshaft 12, the internal rotor 16, and the vane 44 rotate relative to the external rotor 20 in the clockwise direction due to the change in the pressure balance of the hydraulic oil between the advance chamber 76 and the retard chamber 78, and the solenoid 56 rotates. Unless the power is not supplied, the relative rotation is performed to the most advanced position shown in FIG. 3 (the position where the vane 44 in the upper left hydraulic chamber 74 contacts the stopper 82 shown in FIGS. 2 and 3).

On the other hand, when changing the phase from the most advanced position shown in FIG.
6 is de-energized, and the spool 58 is moved to the right end chamber shown in FIG.
By adjusting 66, the hydraulic oil pressurized by the pump 62 is supplied to the retard passage 48, and the hydraulic oil in the advance passage 46 is discharged. As a result, the hydraulic oil in the four advance chambers 76 is discharged, and the hydraulic oil is supplied to the upper left retard chamber 74 shown in FIGS. The camshaft 12, the internal rotor 16, and the vane 44 rotate relative to the external rotor 20 in a direction opposite to the clockwise direction due to the change in the pressure balance of the hydraulic oil between the advance chamber 76 and the retard chamber 78. Unless the solenoid 56 is energized, the most retarded position shown in FIG.
The vane 44 in the upper right hydraulic chamber 74 shown in FIG.
Relative rotation up to the position where it abuts).

In the above operation, when the total volume of the four advance chambers 76 supplied with the hydraulic oil is compared with the volume of one retard chamber 78, there is a difference in the volume, but the pump 62
Is a pump having a large capacity for supplying oil for cooling to the entire internal combustion engine, and the valve timing control device uses only a part of the large capacity. Therefore, 4
The force for rotating the vane 44 in the clockwise direction in the one advance chamber 76 can be four times the force for rotating the vane in the clockwise direction in one retard chamber 78. It is possible to balance with the biasing force to the retard side transmitted to the camshaft 12 when opening and closing the exhaust or intake valve, and the response speed of the phase conversion to the advance and the retard side is substantially the same. can do.

In the above description of the operation, the phase conversion from the most advanced position to the most retarded position has been described. By adjusting the current supplied to the solenoid 56 of the switching valve 50 linearly, By fixing 58 in the middle chamber shown in FIG. 1, the phase of camshaft 12 and external rotor 20 can be fixed at a desired position.

In the first embodiment, the timing sprocket 18 and the crankshaft 3
However, the timing belt 32 is connected by a timing chain 32, but it is also possible to use a timing belt formed of rubber or a resin material. However, in this case, the passage 84 for discharging the hydraulic pressure in the retard chamber 78 to which no hydraulic pressure is supplied so as not to discharge the hydraulic oil to the outside of the external rotor 20.
Instead, it is necessary to form a passage inside.

FIG. 4 shows a second embodiment of the present invention, and the same members as those of the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals. The feature of the second embodiment resides in a method of supplying hydraulic oil, and is characterized in that the switching valve 50 of the first embodiment is replaced by two inexpensive on / off valves 90 and 92 and a check valve 94. As is clear from FIG. 4, the hydraulic oil pressurized by the pump 62 is supplied to the only retard chamber 100 to which hydraulic pressure is always supplied via the retard passage 48. In order to change the phase from the intermediate position shown in FIG. 4 to the advance side, the on-off valve 90 is connected and the on-off valve 92 is closed, so that the advance chambers 102, 104, 1
06, 108 are supplied with hydraulic pressure. To maintain the intermediate position, both on-off valves 90, 92 are closed. When the phase is changed from the intermediate position shown in FIG. 4 to the retard side, the hydraulic pressure is discharged to the advance chambers 102, 104, 106 and 108 by closing the on / off valve 90 and opening the on / off valve 90. When the operating oil is supplied to the advance passage 46, the check valve 94 operates to control the retard chamber 100 and the advance chambers 102, 104, and 1.
Advance chambers 102, 10 and 10
This is for preventing the hydraulic pressure from flowing into the retard chamber 100 from 4, 106, 108.

With the configuration of the embodiment shown in FIG. 4, the use of two relatively inexpensive on / off valves allows
The operation similar to that of the switching valve 50 of the first embodiment shown in FIG. 1 can be ensured, and the manufacturing cost of the valve timing control device can be reduced.

[0028]

As described above, according to the present invention, despite the fact that the camshaft is biased to the retard side by the driving energy for opening and closing the intake / exhaust valves, the relative phase of the valve opening / closing timing control device is controlled. Can be made substantially the same in the phase change of the phase to the advance side and the retard side.

[Brief description of the drawings]

FIG. 1 is an overall view of a valve timing control apparatus according to a first embodiment of the present invention.

FIG. 2 is a drawing showing the phase of the most retarded angle in the first embodiment.

FIG. 3 is a drawing showing the phase of the most advanced angle of the first embodiment.

FIG. 4 is an overall schematic diagram of a second embodiment of the present invention.

[Explanation of symbols]

 12 Camshaft 20 External rotor 22 Front plate 24 Rear plate 44 Vane 46 Advance passage 48 Delay passage 50 Switching valve 74 Hydraulic chamber 76, 102, 104, 106, 108 Advance chamber 78, 100 Delay chamber 90, 92 ON / OFF valve

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G016 AA06 AA19 BA23 CA01 CA11 CA21 CA24 CA27 CA29 CA33 CA36 CA51 DA06 DA22 DA23 EA12 EA13 GA00 3G092 AA11 DA01 DA02 DA09 DF04 DF09 DG02 DG05 DG09 EA28 EA29 FA09 FA48

Claims (3)

[Claims] A camshaft that opens and closes an intake valve or an exhaust valve by rotating in a predetermined direction; a housing that is rotatably mounted on an outer periphery of the camshaft;
A plurality of hydraulic chambers formed between the camshaft and the housing; an advancing chamber attached to the camshaft and each of the hydraulic chambers for advancing a rotational phase of the camshaft with respect to the housing; A plurality of vanes partitioned into a retard chamber for delaying the rotation phase of the shaft with respect to the housing, an advance hydraulic passage for increasing and decreasing the hydraulic pressure of the advance chamber, and a retard hydraulic passage for increasing and decreasing the hydraulic pressure of the retard chamber; And a hydraulic control means for controlling the hydraulic pressures of the advance hydraulic passage and the retard hydraulic passage, wherein the total area of the advance chamber acting on the vane is retarded acting on the vane. A valve timing control device characterized by being larger than the total area of the room. 2. The valve opening / closing timing control device according to claim 1, wherein the retard hydraulic passage communicates only with a part of the plurality of retard chambers. 3. The valve opening / closing timing control device according to claim 1, wherein the hydraulic pressure control means comprises two on / off valves for controlling only the hydraulic pressure of the advance chamber.