JP2890214B2 - Valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a valve operating camshaft for driving an engine valve supported on an engine body so as to be openable and closable. An actuating mechanism having a piston that is capable of controlling the rotational phase of the crankshaft and has one end face in the axial direction facing the hydraulic chamber and a spring biased to a side that reduces the volume of the hydraulic chamber;
The present invention relates to a valve train for an internal combustion engine in which phase control means including a hydraulic control valve for controlling the hydraulic pressure of the hydraulic chamber is provided.

[0002]

2. Description of the Related Art Conventionally, such a valve train is already known, for example, from Japanese Patent Application Laid-Open No. 59-120707.

[0003]

In such a phase control means of a valve train, the hydraulic pressure in the hydraulic chamber is controlled by an electromagnetic control valve at a two-port two-position, thereby controlling the opening / closing timing of the engine valve. However, basically, only two states of operating the hydraulic chamber or releasing the hydraulic pressure are obtained,
Therefore, only two types of rotation phases can be obtained between the valve operating camshaft and the crankshaft. However, depending on the operating state of the engine, particularly in a low to medium speed range, the effect of the change in the rotation phase on the engine performance is large, and the engine performance is significantly improved by changing the rotation phase in multiple stages or continuously. Becomes possible.

Japanese Patent Laid-Open Publication No. Sho 59-120707 discloses that the rotational phase can be continuously changed by finely changing the position of a 2-port 2-position electromagnetic control valve by duty control. However, considering that the amount of oil leak from each gap in the operating mechanism changes in accordance with the operating oil temperature, and that the amount of leak changes due to machining accuracy, the distance between the valve operating cam shaft and the crank shaft is considered. It is necessary to detect the rotational phase and perform feedback control of the electromagnetic control valve, and the configuration becomes complicated because the rotational phase detecting means is required or a feedback control system is required.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has a simple configuration in which the rotation phase between the valve operating camshaft and the crankshaft can be continuously controlled. It is intended to provide a device.

[0006]

According to a first aspect of the present invention, a hydraulic control valve is provided with an input port leading to a hydraulic source, an output port leading to a hydraulic chamber, and an oil tank. Axial direction between a housing having a release port communicating therewith, a refueling position communicating the input port with the output port, a shutoff position isolating the input port, the output port and the release port from each other, and a release position communicating the output port with the release port. A spool slidably fitted to the housing so as to be movable, a spring interposed between the housing and one end of the spool to bias the spool toward the refueling position, An actuator that exerts an operating force that biases toward one side, and a back pressure chamber that communicates with the output port exerts hydraulic pressure toward the release position. So formed so as to face the other end of the spool, the actuator is configured so as to exert a thrust that corresponds to the independent input electrical quantity and an operating position.

According to a second feature of the present invention, the actuator is a linear solenoid.

According to a third aspect of the present invention, a fixed gap is provided between the spool in the shut-off position and the actuator in the inoperative state.

According to a fourth aspect of the invention, the output port communicates with the back pressure chamber via an orifice.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 8 show an embodiment of the present invention. FIG. 1 is an overall vertical sectional side view, FIG. 2 is an enlarged vertical sectional view of a phase control means, and FIG. Corresponding axial thrust characteristic diagram, FIG. 4 is an axial thrust characteristic diagram corresponding to the stroke of the linear solenoid, FIG. 5 is a simplified diagram showing the force acting on the spool of the hydraulic control valve, and FIG. 6 is the application of the linear solenoid. FIG. 7 is an enlarged sectional view of a contact portion between a linear solenoid and a spool, and FIG. 8 is an enlarged vertical sectional view of a lift amount control means.

First, in FIG. 1, an intake valve port 3 opening at the top of a combustion chamber 2 formed between a cylinder block (not shown) and a cylinder block (not shown) is formed in a cylinder head 1 of an engine body E through an intake port 4. At the same time, an intake valve 5 as an engine valve capable of opening and closing the intake valve port 3 is arranged to be vertically movable. A flange 6 is provided at the upper end of the intake valve 5.
A valve spring 7 is contracted between the flange 6 and the cylinder head 1, and the intake valve 5 is urged upward, that is, in the valve closing direction by the spring force of the valve spring 7.

On the other hand, a valve operating cam shaft 9 is rotatably supported on the holder 8 at a position above the cylinder head 1.
The valve gear camshaft 9 is interlocked and connected to a crankshaft (not shown) via a phase control means 10. Also, the valve operating cam shaft 9
A lift control means 12 is interposed between the valve operating cam 11 provided integrally with the intake valve 5 and the intake valve 5.

Referring also to FIG. 2, the phase control means 10
Includes an operating mechanism 13 operable to change the rotational phase of the crankshaft and the valve operating camshaft 9 (not shown), and a hydraulic control valve 14 capable of controlling the hydraulic pressure applied to the operating mechanism 13.

The operating mechanism 13 includes a pulley 16 around which a timing belt 15 for transmitting rotational power from a crankshaft is wound, a rotating shaft 17 coaxially connected to the valve cam shaft 9 by bolts 23, A casing 18 having a substantially cylindrical shape with a bottom, which is provided integrally with the casing 16 and coaxially surrounds the end of the valve cam shaft 9 and the rotating shaft 15, an end plate 19 which closes an open end of the casing 18; A piston 21 slidably fitted to the rotating shaft 17 and the casing 18 while defining a hydraulic chamber 20 between the end plate 19 and a return for urging the piston 21 toward the hydraulic chamber 20. And a spring 22.

The casing 18 has a cylindrical portion 18a coaxially surrounding the valve operating cam shaft 9 at a closed end and is basically formed in a cylindrical shape with a bottom, and is formed between the outer surface of the cylindrical portion 18a and the holder 8. An annular seal member 24 is interposed. The pulley 16 is provided on the outer periphery of the housing 18.

The outer surface of the piston 21 has a housing 18
An O-ring 25 sliding on the inner surface of the rotary shaft 17 is fitted on the inner surface, and an O-ring 26 sliding on the outer surface of the rotating shaft 17 is fitted on the inner surface.
The rotating shaft 17 has a flange portion 17a that protrudes radially outward while facing the closed end of the casing 18, and a cylindrical portion 1 that extends from the outer end of the flange portion 17a to the piston 21 side.
7b, and the return spring 22 is connected to the flange 17
a and the piston 21 is contracted. Moreover, a cylindrical portion 21a disposed between the cylindrical portion 17a and the housing 18 is coaxially protruded from the piston 21. The outer surface of the cylindrical portion 21a and the inner surface of the casing 18 are connected via a helical spline 27. And the cylindrical portion 21
The inner surface of a and the outer surface of the cylindrical portion 17b are connected via a helical spline. Therefore piston 2
1 in accordance with the axial movement of the pulley 16 in the casing 18.
The rotation phase of the crankshaft connected via the timing belt 15 and the rotation shaft 17, that is, the valve gear camshaft 9 changes.

Referring again to FIG. 1, the cylinder head 1 is provided with an oil bath 32 as an oil tank, and a discharge port of an oil pump P as a hydraulic source for pumping oil from the oil bath 32 has An oil supply passage 31 including a relief valve 29 and a filter 30 is connected in order from the upstream side. Moreover, a branch oil passage 33 dedicated to the phase control means 10 and a lift amount control means 12
And a lubricating portion of the cylinder head 1, that is, a journal portion of the valve operating cam shaft 9 and the valve operating cam 11.
Lubricating oil passage 3 for supplying lubricating oil to the sliding contact part
5 is branched, and an orifice 36 is provided in the lubricating branch oil passage 35.

The branch oil passage 33 is provided in the cylinder head 1 and the holder 8 and has a phase control means 1.
Oil passage 37 having one end communicating with hydraulic chamber 20 at 0
The oil passage 37 is formed in the rotary shaft 17 and the valve cam shaft 9.
Is always communicated with the downstream portion 33 b of the branch oil passage 33.
In addition, an accumulator 53 is provided at an upstream portion of the branch oil passage 33.

The hydraulic control valve 14 is interposed between the upstream portion 33a and the downstream portion 33b of the branch oil passage 33. The hydraulic control valve 14 includes a housing 40 attached to a side surface of the cylinder head 1, a spool 41 slidably fitted to the housing 40, a spring 49 for urging the spool 41 to one side in the axial direction, A linear solenoid 42 as an actuator attached to the housing 40 to press the spool 41 in the axial direction.

The housing 40 has an input port 43 connected to the upstream portion 33a of the branch oil passage 33, and an output port 44 connected to the downstream portion 33b of the branch oil passage 33.
And a release port 45 connected to the oil bath 32. The housing 40 has a large-diameter sliding hole 46 having one end closed by a cap 48 and a small-diameter sliding hole 47 coaxially connected to the other end of the large-diameter sliding hole 46. The large-diameter sliding hole 46 and the small-diameter sliding hole 47 are slidably fitted. Thus, a spring 49 is contracted between the cap 48 and one end of the spool 41, and a linear solenoid 42 is coaxially interlocked and connected to the other end of the spool 41. That is, the linear solenoid 42 is
The drive rod 52 of the linear solenoid 42 is coaxially abutted on the other end of the spool 41. Further, a back pressure chamber 51 connected to the output port 44 via the orifice 50 is formed in the housing 40 so as to face the other end of the spool 41.

The spool 41 has a refueling position that connects the input port 43 and the output port 44, a blocking position that separates the output port 44 from the input port 43 and the release port 45, and a release position that communicates the output port 44 with the release port 45. Position the linear solenoid 4 on the other axial end
The switching is performed according to a change in the axial position due to the magnitude relationship between the axial thrust force and the hydraulic pressure of the back pressure chamber 51 and the spring force acting on one end in the axial direction.

The linear solenoid 42, as shown in Figure 3, which generates an axial thrust F _A that proportionally varies according to the input voltage when a constant the input amount of electricity for example applied current I or the resistor It is. Moreover, when the input electrical quantity for example applied current I is constant, as shown in Figure 4, with the exception of unstable areas of working stroke from "0" to a certain value "L _0", regardless of the operating stroke certain thrust corresponding to the applied current I ₀ ~1 / 4I ₀ linear solenoid 42 occurs.

Next, the operation of the hydraulic control valve 14 will be described. In a state where the linear solenoid 42 is demagnetized, the spool 41 is at a refueling position where the input port 43 communicates with the output port 44. In this state, when hydraulic pressure acts on the input port 43 from the upstream portion 33a of the branch oil passage 33,
The hydraulic pressure acts on the downstream portion 33 b of the branch oil passage 33 via the output port 44 and also acts on the back pressure chamber 51 via the orifice 50, and the spring force of the spring 49 is generated by the hydraulic pressure acting on the back pressure chamber 51. Hydraulic pressure acting on the spool 41 presses the output port 44 to a blocking position that isolates the output port 44 from the input port 43 and the release port 45. When a current is applied to the linear solenoid 42, the linear solenoid 42 is driven by the driving rod 52 with an axial thrust corresponding to the applied current.
In the axial direction, whereby the spool 41 is driven to a position that allows the output port 44 to communicate with the release port 45. By controlling the applied current of the linear solenoid 42 in this manner, the spool 41 is provided with a refueling position that connects the input port 43 and the output port 44, a blocking position that isolates the output port 44 from the input port 43 and the release port 45, In addition, the release position at which the output port 44 communicates with the release port 45 is switched, whereby the hydraulic pressure of the upstream portion 33a of the branch oil passage 33 is controlled to act on the downstream portion 33b, that is, the hydraulic chamber 20 of the operation mechanism 13. Become.

FIG. 5 shows the load direction of the hydraulic control valve 14 in a simplified manner as shown in FIG. 5, where the spring load of the spring 49 is F _S , the hydraulic pressure acting on the back pressure chamber 51 is P _C , and the spool 4
Assuming that the pressure receiving area facing the first back pressure chamber 51 is S and the axial thrust of the linear solenoid 42 is F _A , the force for pushing the spool 41 toward the release position (the right position in FIG. 5) and the spool 41 The force pressing toward the refueling position (the left position in FIG. 5) is balanced when the spool 41 is in the shut-off position (the middle position in FIG. 5).
Is obtained.

[0026]

(Equation 1)

The axial thrust F of the linear solenoid 42
_A, as a proportionality constant shown in FIG. 3 when the alpha F _A =
Since αI, Equation 2 is obtained from Equation 1 above.

[0028]

(Equation 2)

Here, the spring load F _S when the spool 41 is in the shut-off position is a constant value determined when the positions of the ports 43, 44, 45 in the housing 40 are set. As shown, the back pressure chamber 51
And the hydraulic pressure in the hydraulic pressure chamber 20 in the hydraulic P _C i.e. actuating mechanism 13 will have a proportional relationship as shown in FIG. 6 and the applied current I of the linear solenoid 42.

Incidentally, in the hydraulic control valve 14,
When the hydraulic pressure P _C of the back pressure chamber 51 i.e. the hydraulic chamber 20 it is assumed that the pressure was reduced than the value to be determined by the applied current I of the linear solenoid 42 due to a leakage or the like, the spool 41 is moved to the oil supply position, the input port 43 and an output The communication between the ports 44 increases the oil pressure in the back pressure chamber 51, and accordingly, the spool 41 moves to the shut-off position and the hydraulic chamber 20
Is controlled to a value corresponding to the applied current I. The linear solenoid 4 pressure P _C of the back pressure chamber 51 by overfilling
Assuming that the pressure is increased from a value to be determined by the applied current I of 2, the spool 41 moves to the release position and the hydraulic pressure in the back pressure chamber 51 decreases due to the communication between the output port 44 and the release port 45. Thereby, the spool 41 moves to the shut-off position, and the hydraulic pressure in the hydraulic chamber 20 is controlled to a value corresponding to the applied current I. In this manner, so that the hydraulic pressure P _C of the hydraulic chamber 20 i.e. the back pressure chamber 51 is provided with the hydraulic control valve 14 is a structure for self-resetting be shifted from a value corresponding to the applied current I of the linear solenoid 42.

As shown in FIG. 7, the spool 41 is in the shut-off position, and the linear solenoid 42 is in the non-operation state.
A gap 54 is provided at a constant interval between the linear solenoid 42 and the linear actuator 42, as shown in FIG. 4, when the operating stroke is between “0” and a certain value “L ₀ ”. In this case, the linear solenoid 42 has an idle stroke, and the linear solenoid 4
2 can be applied.

Further, in the operating mechanism 13, the piston 2
Numeral 1 is connected to the valve operating cam shaft 9 via a helical spline 28. The vibration component of the driving load of the valve operating cam 11 causes the piston 21 to vibrate in the axial direction. There is a possibility that the oil pressure of 51 will fluctuate.
However, since the back pressure chamber 51 communicates with the hydraulic chamber 20 via the orifice 50, fluctuations in the oil pressure in the back pressure chamber 51 can be avoided as much as possible, and adverse effects on the hydraulic control valve 14 can be avoided.

Next, the structure of the lift amount control means 12 will be described with reference to FIG. 8. The lift amount control means 12 includes a transmission mechanism 55 interposed between the intake valve 5 and the valve cam 11. , The transmission oil chamber 5 in the transmission mechanism 55
6, a hydraulic pressure release valve 57 for releasing the hydraulic pressure, an accumulator 58, a feed valve 59, and a check valve 60.

The transmission mechanism 55 includes a cylinder body 62 fixed to a support block 61 fixed to an upper portion of the cylinder head 1 and a support block 61 slidingly contacting the valve cam 11.
A lifter 63 slidably fitted to the upper portion of the cylinder, a cam driven piston 64 slidably fitted to the upper portion of the cylinder body 62 by abutting the upper end of the lifter 63, and an upper end of the intake valve 5. A valve drive piston 65 slidably fitted to the lower portion of the cylinder body 62 while contacting the
A transmission oil chamber 56 is formed between 4 and 65.

The cylinder body 62 has a partition wall 6 at its intermediate portion.
The cam driven piston 64 is slidably fitted to the upper portion of the cylinder body 62 while defining an upper oil chamber 56a between the cam driven piston 64 and the partition wall 66.
The valve drive piston 65 is provided between the lower oil chamber 56 and the partition wall 66.
It is slidably fitted to the lower part of the cylinder body 62 while defining b. Thus, the upper oil chamber 56a and the lower oil chamber 56b
Is connected via a check valve 67 provided on the lower oil chamber 56b side of the partition wall 66 so as to allow only the flow of oil from the upper oil chamber 56a to the lower oil chamber 56b. The transmission oil chamber 56 is formed in cooperation. Upper oil chamber 5
A spring 68 for urging the cam driven piston 64 toward the lifter 63 is housed in 6a.

Further, an annular concave portion 69 is provided on the inner surface of the cylinder body 62 below the partition wall 66.
The oil passage 7 that communicates the annular recess 69 with the upper oil chamber 56a.
0 is drilled in the cylinder body 62. An upper portion of the valve drive piston 65 is formed in a thin cylindrical shape, and an orifice 71 for constantly communicating the lower oil chamber 56b with the annular concave portion 69 is formed in the thin cylindrical portion.

The transmission mechanism 55 is in the state shown in FIG. 3 when the intake valve 5 is fully closed when the hydraulic pressure release valve 57 is closed. From this state, the cam is driven by the rotation of the valve operating cam 11. When the piston 64 is pushed down, the oil pressure in the upper oil chamber 56a is guided to the lower oil chamber 56b via the oil passage 70 and the orifice 71, but the oil pressure in the upper oil chamber 56a is higher than the oil pressure in the lower oil chamber 56b. Is larger than a predetermined value, the check valve 67 opens, so the hydraulic pressure acts on the lower oil chamber 56b from the upper oil chamber 56a via the check valve 67,
The valve drive piston 65 is pushed down.

During the downward sliding of the valve drive piston 65, the oil passage 70 communicates directly with the lower oil chamber 56b through the annular concave portion 69, and the amount of oil flowing into the lower oil chamber 56b becomes large. The drive piston 65 is pushed further downward,
The intake valve 5 opens against the spring force of the valve spring 7.

When the pressing force by the valve cam 11 is released after the intake valve 5 is fully closed, the intake valve 5 is driven upward, that is, in the valve closing direction by the spring force of the valve spring 7.
The valve drive piston 65 is also pushed upward by the closing operation of the intake valve 5, and the oil in the lower oil chamber 56b is returned to the upper oil chamber 56a via the oil passage 70.

Thus, the direct communication between the annular recess 69 and the lower oil chamber 56b is released during the closing operation of the intake valve 5, and the orifice 71 is interposed between the lower oil chamber 56b and the annular recess 69. Then, the return amount of oil from the lower oil chamber 56b to the upper oil chamber 56a is limited. Therefore, the upward moving speed of the intake valve 5, that is, the valve closing speed is relaxed during the valve closing operation, and the intake valve 5 is seated gently, so that the impact at the time of seating is reduced.

When the oil pressure in the transmission oil chamber 56 in the transmission mechanism 55, that is, the oil passage 70 is released during the opening operation of the intake valve 5, the transmission oil chamber 56 overcomes the spring force of the valve spring 7 and The intake valve 5 loses the transmission function of keeping the valve open, and the intake valve 5 receives the elastic force of the valve spring 7 from the oil pressure release even though the valve operating cam 11 keeps pushing the lifter 63 downward. The valve closing operation starts, and the transmission oil chamber 56 contracts.

The hydraulic release valve 57 is connected to the intake valve 5 as described above.
The oil pressure release from the transmission oil chamber 56 during the valve opening operation of the accumulator 58 and the passage 74 formed in the support block 61 in communication with the oil passage 70.
The passage 7 formed in the support block 61 while communicating with 2
5 is interposed.

The hydraulic release valve 57 includes a control valve portion 76,
And an electromagnetic drive unit 77 for driving the control valve unit 76. Thus, the control valve section 76 is
In addition, a main valve body 79 capable of switching between communication and shutoff between the two passages 74 and 75 is slidably fitted and a pilot valve 80 for opening and closing the main valve body 79 is provided. The drive unit 77 is connected to the control valve unit 76 to open and close the pilot valve 80. That is, the valve housing 78 of the control valve section 76 is connected to the casing 81 of the electromagnetic drive section 77.

The main valve body 79 is formed in a bottomed cylindrical shape. The main valve body 79 is provided with a passage 74 on the front surface thereof, that is, a passage 74, while applying the hydraulic pressure of the transmission oil chamber 56 in the valve opening direction.
The housing 78 is urged by a spring so as to shut off
A pilot chamber 82 is formed at the back of the main valve body 79. Therefore, the hydraulic pressure of the passage 74 acts on the main valve body 79 in the valve opening direction, and the hydraulic pressure and spring force of the pilot chamber 82 act on the valve closing direction. Further, the main valve body 79 is provided with an orifice 83 that allows the passage 74 to communicate with the pilot chamber 82.

The pilot valve 80 is connected to the pilot chamber 8.
And an electromagnetic drive unit 7 between the outside and the outside.
7 driven. That is, the electromagnetic drive unit 77 includes a solenoid 84 and a movable core 85 driven by the solenoid 84, and the pilot valve 80 opens according to the movement of the movable core 85 when the solenoid 84 is excited.

In such a hydraulic pressure release valve 57, when the solenoid 84 of the electromagnetic drive unit 77 is excited, the pilot valve 80 opens and the hydraulic pressure in the pilot chamber 82 is released.
Therefore, the balance of the hydraulic pressure acting on both surfaces of the main valve body 79 is lost, and the valve opening force of the passage 74 acting on the front surface thereof overcomes the hydraulic pressure of the pilot chamber 82 and the valve closing force of the spring to open the valve. Operate.

When the pilot valve 80 is closed due to the demagnetization of the solenoid 84, the hydraulic pressure in the passage 74 acts on the pilot chamber 82 via the orifice 83, and the main valve body 79 is closed.

The accumulator 58 includes a support block 61
An accumulator piston 89 is slidably fitted in a bottomed sliding hole 88 provided in the accumulator piston 89 between the closed end of the sliding hole 88 and the accumulator piston 89.
An accumulator spring 91 for urging the accumulator piston 89 in the direction of reducing the volume of the accumulator 92 is provided between the cap 90 closing the open end of the sliding hole 88 and the accumulator piston 89. You.

The feed valve 59 is connected to the accumulator 5
8 is disposed in the support block 61 bypassing the hydraulic pressure release valve 57 between the pressure accumulating chamber 92 and the passage 74, and only allows the oil to flow from the pressure accumulating chamber 92 to the passage 74. It is acceptable. The check valve 60 is connected to the pressure accumulating chamber 9.
2 and a connection portion of the feed valve 59, and is disposed on the support block 61 so as to allow the oil to flow toward the pressure accumulation chamber 92 and the feed valve 59.

The support block 1 is provided with a lift sensor S for detecting the upper end of the intake valve 5 when the intake valve 5 is completely closed.

The transmission mechanism 55, the hydraulic release valve 57, the accumulator 58, the feed valve 59, and the check valve 60 are respectively provided corresponding to the intake valves 5 of each cylinder in the multi-cylinder internal combustion engine. The check valve 60 in each cylinder is connected to a common oil passage 93 formed in the cylinder head 1 in common with each cylinder, and the common oil passage 93 is connected to the branch oil passage 34 including the pressure regulating valve 94. You.

The pressure regulating valve 94 includes a housing 95 mounted on a side surface of the cylinder head 1 and a spool 96 slidably fitted to the housing 95. In the housing 95, an input port 97 connected to the upstream portion 34 a of the branch oil passage 34, an output port 98 connected to the downstream portion 34 b of the branch oil passage 34, and a hole drilled in the cylinder head 1 in communication with the oil bath 32. And a release port 99 connected to the opened release oil passage 100. The housing 95 has a large-diameter sliding hole 101 with one end closed, and a large-diameter sliding hole 1.
A small-diameter sliding hole 102 coaxially continuous with the other end of 01 is bored, and the spool 96 is slidably fitted into the large-diameter sliding hole 101 and the small-diameter sliding hole 102. Thus, a spring 1 is provided between one end of the large-diameter sliding hole 101 and one end of the spool 96.
03 is reduced. Further, the housing 95 has a back pressure chamber 10 connected to the output port 98 through the orifice 104.
5 is formed facing the other end of the spool 96.

The spool 96 has a position for communicating the input port 97 with the output port 98, a position for separating the output port 98 from the input port 97 and the release port 99, and a position for communicating the output port 98 with the release port 99.
Spring 10 acting on one end in the axial direction with the hydraulic pressure of back pressure chamber 105
The switching is performed in accordance with the axial position change due to the magnitude relationship with the spring force of No. 3.

In the pressure regulating valve 94, the back pressure chamber 105
When the hydraulic pressure is low, the spool 96 is at a position where the input port 97 and the output port 98 are communicated as shown in FIG. 3, and in this state, the upstream portion 34a of the branch oil passage 34
When the oil pressure acts on the input port 97 through the output port 98, the oil pressure acts on the downstream portion 34b of the branch oil passage 34 via the output port 98, and also acts on the back pressure chamber 10 via the orifice 104.
5, the output port 98 is connected to the input port 9 against the spring force of the spring 103 by the hydraulic pressure applied to the back pressure chamber 105.
Hydraulic pressure is applied to the spool 96 to push it away from the port 7 and the release port 99. Thus, the output port 98
Is higher, the spool 96 is driven to a position that allows the output port 98 to communicate with the release port 99.
Therefore, the spool 96 moves so that the spring force of the spring 103 and the hydraulic pressure due to the hydraulic pressure of the back pressure chamber 105 are balanced, and the spool 96 moves to a position where the input port 97 communicates with the output port 98. 97 and the release port 99, and the position where the output port 98 communicates with the release port 99, thereby controlling the hydraulic pressure of the upstream portion 34a of the branch oil passage 34 so that the downstream portion 34b, ie, the common oil passage 93.

Next, the operation of this embodiment will be described. In the phase control means 10, the hydraulic pressure acting on the piston 21 by the oil pressure in the hydraulic chamber 20 and the spring force of the return spring 22 for urging the piston 21 are balanced. When the piston 21 is moved to the position where the piston 21 moves, the rotational phase of the crankshaft and the valve operating camshaft 9, that is, the opening / closing timing of the intake valve 5 is continuously controlled. In this case, the hydraulic pressure acting on the hydraulic chamber 20 may be continuously changed. Thus, the hydraulic control valve 14 has a refueling position,
A spring 49 is applied by a spring 49 toward a refueling position on a spool 41 slidably fitted to a housing 40 so as to be axially movable between a shut-off position and a release position. The hydraulic force and the axial thrust of the linear solenoid 42 act toward the release position, and the balance of these forces is used to continuously control the hydraulic pressure in the hydraulic chamber 20. The hydraulic pressure in the hydraulic chamber 20 can be continuously changed by a simple control that only changes the input electric quantity, for example, the applied current.

As another embodiment of the present invention, as shown in FIG. 9, the spool 41 is urged toward the refueling position by the spring force of the spring 49 'and the axial thrust of the linear solenoid 42' and the output port 44 is provided. 'may constitute, in this case, the hydraulic pressure P _C and the linear solenoid 42 which is output from the output port 44' of the hydraulic pressure control valve 14 so as to bias the spool 41 to the release position side as the back pressure applied The relationship with the current I is as shown in FIG.

In the above embodiment, the pump P for pumping the working oil from the oil bath 32 as an oil tank provided in the cylinder head 1 is used as the hydraulic pressure source, but the oil for supplying the lubricating oil around the crankshaft is used. A pump for pumping hydraulic oil from an oil pan serving as a tank may be used as the hydraulic pressure source. Further, the present invention can be implemented in relation to an exhaust valve as an engine valve.

[0058]

As described above, according to the first aspect of the present invention, a hydraulic control valve includes a housing having an input port communicating with a hydraulic source, an output port communicating with a hydraulic chamber, and a release port communicating with an oil tank. Sliding the housing with axial movement between an oiling position that connects the input port to the output port, a blocking position that isolates the input port, the output port, and the release port from each other, and a release position that connects the output port to the release port. A spool fitted freely, a spring interposed between the housing and one end of the spool to bias the spool toward the refueling position, and an operation for biasing the spool in one of its axial directions. A back pressure chamber communicating with the output port faces the other end of the spool so as to exert hydraulic pressure toward the release position. The actuator is configured to exert a thrust corresponding to the input electric quantity irrespective of the operating position, so that the hydraulic pressure in the hydraulic chamber can be continuously controlled by a simple control only by changing the input electric quantity of the actuator. , Thereby making it possible to continuously change the rotation phase between the crankshaft and the valve operating camshaft.

According to the second feature of the present invention, since the actuator is a linear solenoid, characteristics required for the actuator can be easily obtained.

According to the third feature of the present invention, since a constant gap is set between the spool in the shut-off position and the actuator in the non-operation state, the unstable region peculiar to the linear solenoid is established. It is possible to make the linear solenoid exert axial thrust only in the stable region.

According to a fourth aspect of the present invention, the output port communicates with the back pressure chamber through the orifice.
It is possible to prevent the fluctuation of the hydraulic pressure on the hydraulic chamber side from directly acting on the back pressure chamber and adversely affecting the operation of the hydraulic control valve.

[Brief description of the drawings]

FIG. 1 is an overall vertical side view of an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of a phase control means.

FIG. 3 is an axial thrust characteristic diagram corresponding to an applied current of a linear solenoid.

FIG. 4 is an axial thrust characteristic diagram corresponding to a stroke of a linear solenoid.

FIG. 5 is a diagram schematically illustrating a force acting on a spool of the hydraulic control valve.

FIG. 6 is a diagram showing a relationship between an applied current of a linear solenoid and a hydraulic pressure.

FIG. 7 is an enlarged sectional view of a contact portion between a linear solenoid and a spool.

FIG. 8 is an enlarged vertical sectional view of a lift amount control means.

FIG. 9 is a view corresponding to FIG. 5 of another embodiment of the present invention.

10 is a view corresponding to FIG. 6 in the hydraulic control valve of FIG. 9;

[Explanation of symbols]

Reference Signs List 5 intake valve as engine valve 9 valve operating camshaft 10 phase control means 13 operating mechanism 14, 14 'hydraulic control valve 20 hydraulic chamber 21 piston 32 oil bath as oil tank 40 housing 41 spool 42, 42' linear as actuator Solenoid 43 Input port 44 Output port 45 Release port 49, 49 'Spring 50 Orifice 51 Back pressure chamber 54 Air gap E Engine body P Pump as hydraulic pressure source

Continuation of front page (56) References JP-A-1-134011 (JP, A) JP-A-3-54307 (JP, A) JP-A-61-93215 (JP, A) JP-A-61-87913 (JP, A) JP-A-59-120707 (JP, A) JP-A-2-298612 (JP, A) JP-A-4-136405 (JP, A) JP-A-2-76108 (JP, U) JP-A 58-42334 (JP, U) Japanese Utility Model 62-57711 (JP, U) Japanese Utility Model Utility Model 55-104704 (JP, U) Japanese Utility Model Application Hei 3-99806 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) F01L 1/34

Claims (4)

(57) [Claims] An engine valve (5) supported on an engine body (E) so as to be openable and closable for driving an engine valve (5) between a camshaft (9) and a crankshaft according to an axial movement position. A piston which is capable of controlling the rotational phases of the camshaft (9) and the crankshaft and has one axial end face facing the hydraulic chamber (20) and is spring-biased to the side of reducing the volume of the hydraulic chamber (20). An operating mechanism (13) having (21) a hydraulic control valve (14, 14 ') for controlling the hydraulic pressure of the hydraulic chamber (20);
In the valve train of an internal combustion engine provided with a phase control means (10) having the following, the hydraulic control valves (14, 14 ')
The input port (43) leading to the hydraulic pressure source (P) and the hydraulic chamber (2)
0) and the oil tank (3)
A housing (40) with a release port (45) leading to 2) and an input port (43) connected to an output port (44);
Between the refueling position, the shutoff position isolating the input port (43), the output port (44) and the release port (45) from each other, and the release position communicating the output port (44) with the release port (45). A spool (41) slidably fitted to the housing (40) so as to be axially movable, and a housing (40) and a spool (41) for biasing the spool (41) toward the refueling position.
A spring (49, 49 ') interposed between one ends of the spool (41), and an actuator (42, 42') for exerting an operating force on the spool (41) in one of its axial directions, A back pressure chamber (51) communicating with the output port (44) is provided with a spool (4) for exerting hydraulic pressure toward the release position.
The internal combustion engine is formed so as to face the other end of 1), and the actuator (42, 42 ') is configured to exert a thrust corresponding to an input electric quantity irrespective of an operation position. Valve gear. 2. A valve operating apparatus for an internal combustion engine according to claim 1, wherein said actuator (42, 42 ') is a linear solenoid. 3. A gap (54) is provided between the spool (41) in the shut-off position and the actuator (42, 42 ') in the non-operation state. 3. The valve train for an internal combustion engine according to 2. 4. The valve train for an internal combustion engine according to claim 1, wherein said output port is communicated with a back pressure chamber via an orifice.