JP2832624B2 - Valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of the Invention The present invention relates to an engine valve and a crankshaft supported by a cylinder head so as to be able to open and close according to a change in hydraulic pressure in a hydraulic chamber. The present invention relates to a valve operating device for an internal combustion engine in which valve operating mode changing means capable of changing the operating mode of the engine valve is provided.

(2) Prior Art Conventionally, such a valve train is disclosed in, for example, Japanese Patent Application Laid-Open No.
And Japanese Patent Application Laid-Open No. 61-275516.

(3) Problems to be Solved by the Invention In the valve operating mode changing means described in the above publication, a cam driven piston is slidably fitted on an upper part of a cylinder body fixed to a cylinder head, and the cam driven piston is A valve driving piston that forms a hydraulic chamber is slidably fitted to the lower part of the cylinder body, and when the operation of the engine is stopped for a relatively long time, the valve driving piston is located between the outer surface of the valve driving piston and the inner surface of the cylinder. The hydraulic oil in the hydraulic chamber leaks downward from the minute interval. For this reason, the operating oil in the oil passage connected to the hydraulic chamber above the lowermost position of the sliding portion of the valve drive piston and the cylinder body in the closed state of the engine valve leaks, and when the engine is restarted. Oil supply to the hydraulic chamber may be delayed.

The present invention has been proposed in view of the above, and has as its main object to avoid a delay in refueling a hydraulic chamber due to a hydraulic oil leak in the valve train.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above object, according to a first feature of the present invention, between an engine valve and a crankshaft supported by a cylinder head so as to open and close. In a valve operating device for an internal combustion engine in which valve operating mode changing means capable of changing the operating mode of the engine valve in accordance with a change in the hydraulic pressure of the hydraulic chamber is provided, the valve operating mode changing means is fixed to a cylinder head. Cylinder body,
A cam driven piston slidably fitted to the upper part of the cylinder body while being interlocked and connected to a valve operating cam shaft connected to a crankshaft, and slidable to a lower part of the cylinder body while being interlocked and connected to an engine valve. A valve drive piston fitted to the
A hydraulic chamber formed between the two pistons in the Cinder body to mutually transmit the operations of the two pistons, and a hydraulic release valve connected to the hydraulic chamber, wherein the hydraulic release valve is branched from an oil supply passage connected to an oil pump. In the middle part of the branch oil passage for the valve operation mode changing means connected to the hydraulic chamber, a high position higher than a horizontal line passing through the lowermost positions of the sliding portions of the valve drive piston and the cylinder body when the engine valve is closed. And a lower portion that is lower than the horizontal line and that continues to the hydraulic chamber side end of the higher portion.

According to a second aspect of the present invention, the oil pump is an oil pump dedicated to a cylinder head disposed on a cylinder head for pumping hydraulic oil from an oil bath provided on the cylinder head. According to the third feature, in addition to the second feature, each lubricating portion of the valve train including the valve train camshaft connected to the crankshaft and the valve operation mode changing means is connected to the cylinder head dedicated oil pump. A lubrication branch oil passage branched from the oil supply passage is connected.

Further, according to the fourth aspect of the present invention, the valve operation mode changing means includes an accumulator and the accumulator and the hydraulic chamber so as to bypass the accumulator and the hydraulic release valve interposed between the accumulator and the hydraulic chamber. A one-way valve that is interposed between the valves and opens at a set valve opening pressure to allow only the flow of the hydraulic oil to the hydraulic chamber side, and only the flow of the hydraulic oil to the one-way valve and the accumulator side. A check valve connected between the accumulator and the one-way valve to allow, and a branch oil passage for valve operation mode changing means connected to the check valve while being branched from an oil supply passage connected to the oil pump. According to a fifth aspect of the present invention, in addition to the fourth aspect, a transmission mechanism including both the pistons and the cylinder body and the hydraulic release valve are provided on a plurality of engine valves. It is arranged correspondingly individually, Accumulator is arranged in common to the transmission mechanism.

According to a sixth aspect of the present invention, in addition to the first, second or third aspect, a hydraulic pressure difference between the branch oil passage for the valve operation mode changing means and the hydraulic chamber is provided. A plurality of one-way valves are provided in parallel with each other to allow the flow of the hydraulic oil from the branch oil passage for the valve operation mode changing means to the hydraulic chamber side when the pressure becomes equal to or more than a predetermined value.

(2) Operation According to the configuration of the first aspect, the lower portion is connected to the hydraulic chamber side end of the higher portion provided in the middle portion of the branch oil passage for the valve operation mode changing means. Even if the hydraulic oil in the hydraulic chamber leaks from the sliding part of the body and the valve drive piston, the hydraulic oil can be stored at least in the lower part of the branch oil passage for the valve operation mode changing means.

Further, according to the configuration of the second feature, the oil chamber dedicated to the cylinder head is connected to the hydraulic chamber of the valve operation mode changing means provided in the cylinder head, so that the oil pump and the hydraulic chamber are connected to each other. The distance between them can be made relatively short, and the hydraulic chamber can be refueled quickly at the time of starting.

Further, according to the configuration of the third aspect, each lubricating portion of the valve train including the valve train camshaft and the valve operating mode changing means connected to the crankshaft is branched from the oil supply passage connected to the cylinder head dedicated oil pump. Since the lubricating branch oil passage is connected, the distance between the oil pump and each lubrication passage can be made relatively short, and the lubricating portion can be quickly lubricated at the time of starting.

Further, according to the configuration of the fourth aspect, since the oil pressure supplied to the valve operation mode changing means is adjusted by the pressure adjusting valve, the oil pump which discharges the operating oil at a pressure equal to or higher than the pressure required by the valve operation mode changing apparatus is used. Lubricating parts other than the valve operation mode changing means can be supplied with oil.

Further, according to the configuration of the fifth aspect, since the accumulators are arranged in common to the plurality of transmission mechanisms, the number of accumulators can be smaller than the number of transmission mechanisms.

Further, according to the configuration of the sixth aspect, by using a plurality of one-way valves, each one-way valve can be downsized,
Accordingly, the opening / closing operation of each one-way valve is speeded up, and it is possible to speed up oil supply to the hydraulic chamber as a whole and to prevent leakage from the hydraulic chamber.

(3) Example Hereinafter, an example of the present invention will be described with reference to the drawings.

Referring to the first embodiment of the present invention with reference to Figure 1 to Figure 3, first in Figure 1, the engine body E, and a lower oil supply system O _D, mutually upper oil supply system O _U It is arranged independently. Thus the lower oil supply system O _D with the hydraulic oil from the oil pan 1 is disposed in the lower portion of the engine body E to the discharge port of the pumping gel the oil pump P, the oil supply passage 3 provided with a filter 4 is a relief valve 2 A plurality of branch oil passages 5, 6... Branched from the oil supply passage 3 are respectively connected to hydraulic oil consumption units such as a crank journal portion 7 and a cooling jet 8 provided at a lower portion of the engine body E. Be connected. The upper oil supply system O _U is provided with the cylinder head 9 for pumping hydraulic oil from an oil bath 10 provided in a cylinder head 9 (see FIG. 2) constituting an upper portion of the engine body E.
To disposed a cylinder head dedicated oil pump P _C of the discharge port, the oil supply passage 13 provided with a filter 12 is connected through a relief valve 11, pressure regulating valve 14 has a valve operation mode changing means 15
A lubricating oil passage having a branch oil passage 16 for valve operation mode changing means connected to the lubricating unit and an orifice 17 connected to each lubricating unit disposed on the cylinder head 9 such as the cam journal unit 18 and the cam shower unit 19. The branch oil passage 20 is branched from the oil supply passage 13.

The valve operation mode changing means 15 is capable of changing the valve opening lift amount operation mode of the engine valve according to the operation state of the engine,
Next, a configuration of a portion related to the valve operation mode changing means 15 will be described with reference to FIG.

The cylinder head 9 has an intake valve opening that opens at the top of a combustion chamber 21 formed between the cylinder head 9 and a cylinder block (not shown).
22 is drilled through the intake port 23, and an intake valve V as an engine valve capable of opening and closing the intake valve port 22 is disposed so as to be vertically movable with an axis inclined sideways from a vertical axis. Is done. A flange 24 is provided at the upper end of the intake valve V.
A valve spring 25 is contracted between the cylinder head 9 and the cylinder head 9. Thus, the intake valve V is urged upward, that is, in the valve closing direction by the spring force of the valve spring 25.

On the other hand, at a position above the cylinder head 9, a valve operating camshaft 26 linked to and connected to a crankshaft (not shown) is rotatably disposed. Between the cam 27 and the intake valve V, valve operating mode changing means 15 is provided.

The valve operation mode changing means 15 includes an intake valve V and a valve operating cam 27.
The transmission mechanism 30 includes a transmission mechanism 30 interposed therebetween and a hydraulic circuit 32 connected to a hydraulic chamber 31 in the transmission mechanism 30.

The transmission mechanism 30 includes a cylinder body 34 fixed to the support block 33 fixed to the upper part of the cylinder head 9 coaxially with the intake valve V, and the support block 33 while slidingly contacting the valve cam 27.
Lifter 35 slidably fitted to the upper part of the
A cam driven piston 36 as a cam-side operating member, which is slidably fitted to the upper portion of the cylinder body 34 with its upper end abutting on
And a valve drive piston 37 as a valve-side operating member slidably fitted to the lower portion of the cylinder body 34 while abutting on the upper end of the intake valve V. A hydraulic chamber 31 is provided between the pistons 36, 37. It is formed.

The cylinder body 34 is formed in a cylindrical shape having a partition wall 38 at an intermediate portion thereof, and the cam driven piston 36 defines an upper hydraulic chamber 31a between the cylinder body 34 and the cylinder body 3 while defining the upper hydraulic chamber 31a.
The valve drive piston 37 is slidably fitted to the lower portion of the cylinder body 34 while defining a lower hydraulic chamber 31b between itself and the partition wall 38. The upper hydraulic chamber
The lower hydraulic chamber 31a and the lower hydraulic chamber 31b are partitioned by a partition wall 38 so as to allow only the flow of oil from the upper hydraulic chamber 31a to the lower hydraulic chamber 31b.
Are connected via a check valve 39 disposed on the lower hydraulic chamber 31b side, and form the hydraulic chamber 31 in cooperation.
In the upper hydraulic chamber 31a, a cam driven piston 36 is
The spring 40 biasing to the fifth side is housed.

Moreover, an annular recess 41 is provided on the inner surface of the cylinder body 34 below the partition wall 38, and an oil passage 42 communicating the annular recess 41 and the upper hydraulic chamber 31a is formed in the cylinder body 34. The upper portion of the valve drive piston 37 is formed in a thin cylindrical shape, and an orifice 43 for constantly communicating the lower hydraulic chamber 31b with the annular concave portion 41 is formed in the thin cylindrical portion.

The transmission mechanism 30 is in the state shown in FIG. 2 when the intake valve V is fully closed when the hydraulic pressure in the hydraulic chamber 31 is not released, and from this state, the cam driven piston 37 Is depressed downward, the hydraulic pressure in the upper hydraulic chamber 31a is reduced via the oil passage 42 and the orifice 43.
When the hydraulic pressure in the upper hydraulic chamber 31a is larger than the hydraulic pressure in the lower hydraulic chamber 31b by a predetermined value or more, the check valve 39
Is opened, hydraulic pressure acts on the lower hydraulic chamber 31b from the upper hydraulic chamber 31a via the check valve 39, and the valve drive piston 37 is pushed downward.

During the downward sliding of the valve driving piston 37, the oil passage 42 communicates directly with the lower hydraulic chamber 31b via the annular concave portion 41, and the amount of oil flowing into the lower hydraulic chamber 31b increases, so that the valve driving piston 3
7 is pushed further downward, and the intake valve V opens against the spring force of the valve spring 25.

When the pressing force by the valve cam 27 is released after the intake valve V is fully opened, the intake valve V is driven upward, that is, in the valve closing direction by the spring force of the valve spring 25. This intake valve V
The valve drive piston 37 is also pushed upward by the valve closing operation, and the oil in the lower hydraulic chamber 31b is returned to the upper hydraulic chamber 31a via the oil passage.

When the direct communication between the annular recess 41 and the lower hydraulic chamber 31b is released during the closing operation of the intake valve V, and the orifice 43 is interposed between the lower hydraulic chamber 31b and the annular recess 41, the lower The amount of oil returned from the hydraulic chamber 31b to the upper hydraulic chamber 31a is limited. For this reason, the upward moving speed of the intake valve V, that is, the valve closing speed is relaxed during the valve closing operation,
When the intake valve V is gently seated, the shock at the time of seating is reduced.

The support block 33 is provided with a lift sensor S for detecting the upper end of the intake valve V when the intake valve V is completely closed.

When the hydraulic pressure in the hydraulic chamber 31, that is, the oil passage 42 in the transmission mechanism 30 is released during the opening operation of the intake valve V, the hydraulic chamber 31 is released.
Will lose the transmission function of continuing to open the intake valve V by overcoming the spring force of the valve spring 25, and the intake valve V will not move even though the valve cam 27 continues to push the lifter 35 downward. When the hydraulic pressure is released, the valve closing operation is started by the elastic force of the valve spring 25, and the hydraulic chamber 31 contracts.

The hydraulic circuit 32 is responsible for releasing the hydraulic pressure from the hydraulic chamber 31 and supplying hydraulic oil to the hydraulic chamber 31, and includes a hydraulic release valve 44, an accumulator 45, and a pair of one-way valves 46,4.
6 and a check valve 47 are provided on the support block 33.

The hydraulic release valve 44 is provided between a passage 48 communicating with the oil passage 42 and formed in the support block 33 and a passage 49 formed in the support block 33 while communicating with the accumulator chamber 63 of the accumulator 45. Is established. The hydraulic release valve 44 includes a control valve portion 51 and an electromagnetic drive portion 52 that drives the control valve portion 51. The control valve portion 51 is provided in the valve housing 53 between the two passages 48 and 49. A pilot valve that is slidably fitted with a main valve body 54 that can switch between communication and cutoff and controls opening and closing movement of the main valve body 54
The electromagnetic drive unit 52 is connected to the control valve unit 51 so as to open and close the pilot valve 55. That is, the valve housing 53 of the control valve unit 51 is provided on the casing 56 of the electromagnetic drive unit 52.
Are combined.

The main valve body 54 is formed in a bottomed cylindrical shape. And the main valve body
54 is spring-biased on the front surface thereof in a direction to shut off between the passages 48 and 49 while applying the hydraulic pressure of the passage 48, that is, the hydraulic chamber 31 in the valve opening direction, and is slidably fitted in the valve housing 53. A pilot chamber 57 is formed behind the main valve body 54. Therefore, the hydraulic pressure of the passage 48 acts on the main valve element 54 in the valve opening direction, and the hydraulic pressure and spring force of the pilot chamber 57 act on the valve closing direction. Further, a passage 48 is provided in the main valve body 54.
An orifice 58 is provided to communicate with the pilot chamber 57.

The pilot valve 55 is interposed between the pilot chamber 57 and the outside, and is driven by the electromagnetic drive unit 52. That is, the electromagnetic drive unit 52 includes a solenoid 59 and a movable core 60 driven by the solenoid 59, and the pilot valve 55 opens according to the movement of the movable core 60 when the solenoid 59 is excited.

In such a hydraulic release valve 44, when the solenoid 59 of the electromagnetic drive unit 52 is excited, the pilot valve 55 is opened, and the hydraulic pressure in the pilot chamber 57 is released. Accordingly, the balance of the hydraulic pressure acting on both sides of the main valve element 54 is lost, and the valve opening force of the passage 48 acting on the front surface thereof due to the hydraulic pressure is reduced by the pilot chamber.
Hydraulic release valve overcoming 57 hydraulic and spring closing forces
44 is opened.

When the pilot valve 55 is closed by the demagnetization of the solenoid 59, the hydraulic pressure of the passage 48 acts on the pilot chamber 57 via the orifice 58, the main valve body 54 operates in the valve closing direction, and the hydraulic release valve
44 is closed.

The accumulator 45 has an accumulator piston 62 slidably fitted in a bottomed sliding hole 61 provided in the support block 33, and accumulator pressure is stored between the closed end of the sliding hole 61 and the accumulator piston 62. A chamber 63 is defined, and an accumulator spring 65 for urging the accumulator piston 62 in a direction to reduce the volume of the accumulator chamber 63 is contracted between a cap 64 closing the open end of the sliding hole 88 and the accumulator piston 62. Is done.

Referring also to FIG. 3, a pair of one-way valves 46, 46
Between the passage 67 communicating with the accumulator chamber 63 of the accumulator 45 and the passage 48, they are arranged in the support block 33 in parallel with each other while bypassing the hydraulic pressure release valve 44, and The valve is opened when the oil pressure becomes higher than the oil pressure in the passage 48 by a set pressure or more, and only the flow of oil from the accumulator 63 to the passage 48 is permitted.

These one-way valves 46, 46 are provided in the valve chamber 68 provided in the support block 33 while communicating with the passage 48, and the passage 67
A valve body 70 capable of opening and closing a valve hole 69 opened to the valve chamber 68 while communicating with the valve chamber 68 is housed while being urged by a spring 71 in a valve closing direction. At the open end of the valve hole 69 to the valve chamber 68, a tapered valve seat 72 is provided, and the valve body 70 is formed in a shape that can be seated on the valve seat 72. That is, the valve body 70
Is formed in a mushroom shape having an umbrella portion 70b provided at the tip of the shaft portion 70a, and a spherical contact surface 70c that can be seated on the valve seat 69 is formed on the outer surface near the tip of the umbrella portion 70b. And made of ceramics such as alumina, silicon nitride and zirconia.

When the valve body 70 has the shape described above, the size of the one-way valve 46 can be reduced. That is, conventionally, the valve body is generally a sphere as shown by a chain line in FIG. 3, but by forming a mushroom shape, the axial length and the maximum diameter of the valve body can be reduced, The overall size can be reduced. In addition, since the valve body 70 is made of ceramic, the weight can be further reduced in addition to the weight reduction associated with the miniaturization, and the operation responsiveness can be improved accordingly.

Referring again to FIG. 2, the check valve 47 includes an accumulator 45
Between the pressure accumulation chamber 63 and the two-way valves 46, 46, that is, between the passage 67 and the branch oil passage 16 for the valve operation mode changing means, and the branch oil path 16 for the valve operation mode changing means. From the valve passage 73 to the passage 67 side, and the valve is connected to the valve chamber 73 provided in the support block 33 in communication with the passage 67, while communicating with the branch passage 16 for valve operation mode changing means. A spherical valve body 75 that can open and close a valve hole 74 that opens into the chamber 73 is housed.
Moreover, the valve body 75 is formed of a ceramic such as alumina, silicon nitride, and zirconia. Such check valve 47, even if relatively low hydraulic pressure supplied from the valve operation mode changing means for branch oil passage 16 is possible opening, contributing to the output reduction of the cylinder head only the oil pump P _C Can be.

By the way, the transmission mechanism 30 and the hydraulic circuit 32 are respectively provided corresponding to the intake valves V of each cylinder in the multi-cylinder internal combustion engine. On the other hand, the branch oil passage 16 for the valve operation mode changing means includes an upstream portion 16a connected to the oil supply passage 13 and a downstream portion 16b connected to the check valve 47 in the hydraulic circuit 32 corresponding to each intake valve V. The pressure regulating valve 14 is interposed therebetween, and the downstream portion 16b includes a common oil passage 76 common to each hydraulic circuit 32.

The pressure regulating valve 14 includes a housing 78 attached to a side surface of the cylinder head 9 and a spool 79 slidably fitted to the housing 78. The housing 78 has an input port 80 connected to the upstream portion 16a of the branch oil passage 16 for valve operation mode changing means, an output port 81 connected to the downstream section 16b of the branch oil passage 16 for valve operation mode changing means, and an oil. A release port 83 communicating with the bus 10 and communicating with a release oil passage 82 formed in the cylinder head 9 is provided. The housing 78
A large-diameter sliding hole 84 having one end closed and a small-diameter sliding hole 85 coaxially connected to the other end of the large-diameter sliding hole 84 are formed. It is slidably fitted in the moving hole 85. Thus, a spring 86 is contracted between one end of the large-diameter sliding hole 84 and one end of the spool 79. Further housing 78
An output chamber 88 connected to the output port 81 via the orifice 87 is formed facing the other end of the spool 79.

The spool 79 moves the position where the input port 80 communicates with the output port 81, the position where the output port 81 is isolated from the input port 80 and the release port 83, and the position where the output port 81 communicates with the release port 83, into the output chamber 88. The switching is performed according to a change in the axial position due to the magnitude relationship between the hydraulic pressure of the spring 86 and the spring force of the spring 86 acting on one end in the axial direction.

In such a pressure regulating valve 14, when the oil pressure in the output chamber 88 is low, the spool 79 is located at a position where the input port 80 and the output port 81 communicate with each other as shown in FIG.
When oil pressure acts on the input port 80 from the upstream portion 16a of the branch oil passage 16 for valve operation mode changing means, the oil pressure is applied to the output port.
It acts on the downstream portion 16b of the branch oil passage 16 for the valve operation mode changing means via 81 and the output chamber 8 via the orifice 87.
8, the hydraulic pressure acting on the output chamber 88 causes the oil pressure to press the output port 81 to a position separating from the input port 80 and the release port 83 against the spring force of the spring 86.
Acts on 79. When the hydraulic pressure of the output port 81 further increases, the spool 79 is driven to a position where the output port 81 communicates with the release port 83. So Spare 79 is
The input port 80 and the output port are moved so that the spring force of the spring 86 and the hydraulic pressure of the output chamber 88 are balanced.
81, the position that isolates the output port 81 from the input port 80 and the release port 83, and the output port
The position at which 81 communicates with the release port 83 is switched, whereby the hydraulic pressure of the upstream portion 16a of the branch oil passage 16 for the valve operation mode changing means is controlled and acts on the downstream portion 16b.

The downstream portion 16b of the branch oil passage 16 for the valve operation mode changing means
Is provided with a common oil passage 76 on the way to connect the output port 81 of the pressure regulating valve 14 and the check valve 47 in the hydraulic circuit 32 of each intake valve V, but in the middle of the downstream portion 16b. , Valve drive piston in the closed state of the intake valve V (the state shown in FIG. 2)
A higher portion 16b _U higher than the horizontal line L which passes through 37 and the lowermost position of the sliding portion of the cylinder body 34, lower and lower portion 16b _D is provided than the horizontal line L. Moreover low portion 16b _D are those comprising a common oil channel 76, the upstream end of the lower portion 16b _D is connected to the hydraulic chamber 31 side end or the downstream end of the high portion 16b _U. That is, the hydraulic oil after pressure regulation by the pressure regulating valve 14 is guided to the position above the horizontal line L by the high portion 16b _U , and then guided to the position below the horizontal line L by the low portion 16b _D , Further, it is led to the hydraulic circuit 32 of each valve operation mode changing means 15.

The highest portion of the higher portion 16b _U is an air vent means 90 are provided. The air venting means 90 may be a check valve that closes in response to a hydraulic pressure acting on the downstream portion 16b of the valve operating mode changing means branch oil passage 16, and allows some leakage of hydraulic oil. In this case, the inside of the downstream portion 16b may be communicated with the outside by an orifice.

Next, the operation of the first embodiment will be described. In the valve operation mode changing means 15, when the hydraulic release valve 44 is opened during the opening operation of the intake valve V, the hydraulic pressure in the hydraulic chamber 31 is stored in the accumulator 45. The lift amount of the intake valve V can be controlled by controlling the hydraulic pressure release timing.

By the way, when the oil pressure in the hydraulic chamber 31 is released during the valve opening operation, the oil pressure in the pressure accumulating chamber 63 is returned to the hydraulic chamber 31 via the pair of one-way valves 46, 46 before the next valve opening operation starts. The shortage is supplied to the hydraulic chamber 31 via the check valve 47. Thus the check valve
The hydraulic pressure acting on the oil passage 67 via 47 needs to be between the lower limit pressure that is the valve opening pressure of the one-way valves 46 and 46 and the upper limit pressure that is the accumulation start pressure of the accumulator 45. The hydraulic pressure is adjusted by the pressure adjusting valve 14 so as to fall within such a range.
Therefore, the cam journal section 18 and the cam shower section
A valve operating mode changing means 15 that requires a hydraulic pressure different from the hydraulic pressure at each lubricating portion disposed on the cylinder head 9 such as 19
Hydraulic can pressure regulated by the pressure regulating valve 14 to the can cover the lubrication necessary hydraulic pressure to the different respective portions of a single cylinder head dedicated oil pump P _C.

Moreover the cylinder head only the oil pump P _C is intended to be disposed hydraulic oil to the cylinder head 9 Beku pumping gel from the oil bath 10 provided in the cylinder head 9, the hydraulic pressure chamber 31 and the valve operation mode changing means 15 cylinder heads oil pump P _C distance can be relatively short that the, thus, at the time of start of the engine, it is possible to perform fueling to the hydraulic chamber 31 of the valve operation mode changing means 15 quickly.

When the operation of the engine is stopped for a relatively long time, the hydraulic oil in the hydraulic chamber 31 leaks downward from the minute gap between the outer surface of the valve drive piston 37 and the inner surface of the cylinder body 34 in the valve operation mode changing means 15. I do. However, the horizontal line L passing through the lowermost position of the sliding portion of the valve drive piston 37 and the cylinder body 34 in the closed state of the intake valve V is located on the downstream side portion 16b of the branch oil passage 16 for the valve operation mode changing means. Higher high part 16b
And _U, because the and the lower portion 16b _D which was lower than the horizontal line L connected to the hydraulic chamber 31 side end portion of the higher portion 16b _U is provided, at least on low portion 16b _D be the leakage occurs Hydraulic oil can be stored. Moreover, the lower part 16b _D
Includes a common oil passage 76 having a relatively large capacity, so that a relatively large amount of hydraulic oil can be stored, and when the engine is restarted, supply to the hydraulic chamber 31 is promptly performed to change the valve operation mode. It can be prepared for the activation of the means 15.

Further, the hydraulic circuit 32 in the valve operation mode changing means 15
Is provided with a pair of one-way valves 46, 46 in parallel with each other, and compared with a single one-way valve, the one-way valves 46, 46 have the same opening area. Miniaturization is possible. Therefore, the operation of the valve body 70 is speeded up, a delay in refueling the hydraulic chamber 31 when the valve is opened is avoided, and the valve body 70 is closed when the valve is closed.
Can be quickly seated to prevent the useless leakage from the hydraulic chamber 31 from occurring.

FIG. 4 shows a second embodiment of the present invention, in which parts corresponding to those in the first embodiment are denoted by the same reference numerals.

From an oil supply passage 3 connected to an outlet of an oil pump P for pumping hydraulic oil from an oil pan 1, branch oil passages 5, 6,. And a branch oil passage 16 for valve operation mode changing means connected to the valve operation mode changing means 15 having a pressure regulating valve 14, and a cam journal section 18 and a cam shower section 19 having an orifice 17 And the like, and a lubricating branch oil passage 20 connected to the lubricating portion is branched.

According to the second embodiment, since the hydraulic oil regulated by the pressure regulating valve 14 is supplied to the valve operation mode changing means 15 which requires a hydraulic pressure within a certain range, each of the lubricating parts and the hydraulic oil consumption is reduced. Hydraulic oil having a hydraulic pressure different from the hydraulic pressure required in the section can be supplied from a single oil pump P to the valve operation mode changing means 15.

FIG. 5 shows a third embodiment of the present invention, in which parts corresponding to the above embodiments are given the same reference numerals.

The transmission mechanism 30, the hydraulic release valve 44, and the one-way valve 46 are individually provided corresponding to each intake valve V, and the accumulator 45 and the check valve 47 are each provided in common with the plurality of engine valves V. Are arranged one by one. By doing so, the number of the accumulator 45 and the check valve 47 can be reduced, which can contribute to the reduction in the number of components, and also avoids the complexity of the circuit due to the provision of the accumulator 45 and the check valve 47. Can be.

In still Figure 5, as a hydraulic source for fueling the hydraulic fluid to the transmission mechanism 30, an oil bath 10, the cylinder head only the oil pump P _C, the relief valve 11, and the filter
14 or an oil pan 1, an oil pump P, a relief valve 2 and a filter 4.

In each of the above embodiments, the intake valve has been described as the engine valve. However, the present invention can be implemented in connection with the exhaust valve as the engine valve.

C. Effects of the Invention As described above, according to the first feature of the present invention, the lower portion is connected to the hydraulic chamber side end of the higher portion provided in the middle portion of the branch oil passage for the valve operation mode changing means. Even if the hydraulic oil in the hydraulic chamber leaks when the engine valve is stopped, the hydraulic oil can be stored at least in the lower part of the branch oil passage for the valve operation mode changing means, and the hydraulic oil operates in the hydraulic chamber when the engine is restarted. Oil can be supplied promptly.

According to the second feature, in particular, since the hydraulic chamber of the valve operation mode changing means is supplied with oil from the cylinder head dedicated oil pump, the distance between the oil pump and the hydraulic chamber is relatively short, It is possible to prevent an operation delay at the time of starting.

According to the third feature, in particular, the lubrication portions branched from the oil supply passage connected to the cylinder head dedicated oil pump are provided to each lubrication portion of the valve train including the valve train camshaft connected to the crankshaft and the valve operation mode changing means. Since the branch oil passage is connected, the distance between the oil pump and each lubricating part can be made relatively short, and the lubricating part can be quickly lubricated at the time of starting.

According to the fourth feature, in particular, the operating oil adjusted by the pressure adjusting valve is supplied to the valve operation mode changing means. Therefore, a necessary minimum oil pump is used to lubricate the lubricating parts other than the valve operation mode changing apparatus. It becomes possible.

According to the fifth feature, in particular, since the accumulators are arranged in common for the plurality of transmission mechanisms, the number of accumulators can be reduced, the number of parts can be reduced, and the circuit configuration can be simplified.

According to the sixth feature, in particular, by using a plurality of one-way valves, the size of each one-way valve is reduced, the opening / closing operation of each one-way valve is speeded up, the speed of oil supply to the hydraulic chamber, and Can be prevented from leaking.

[Brief description of the drawings]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a view showing an oil supply system of an engine body, FIG. 2 is a longitudinal sectional view showing a structure of a valve operation mode changing means, FIG. 3 is an enlarged longitudinal sectional view of the one-way valve, FIG. 4 is a diagram of a fuel supply system according to a second embodiment of the present invention, and FIG. 5 is a diagram of a fuel supply system according to a third embodiment of the present invention. 3, 13 ... oil supply path, 9 ... cylinder head, 10 ... oil bath, 14 ... pressure regulating valve, 15 ... means for changing valve operation mode, 16 ...
… Branch oil passage for valve operation mode changing means, 16b _D …… Lower part, 16
b _U ... high section, 20 ... branch oil passage for lubrication, 26 ... valve-operated camshaft, 30 ... transmission mechanism, 31 ... hydraulic chamber, 34 ... cylinder body, 36 ... as cam-side operating member Cam driven piston,
37: Valve-driven piston as a valve-side operating member, 44: Hydraulic release valve, 45: Accumulator, 46: One-way valve, 47
...... check valve, L ...... horizon, P ...... oil pump, P _C ...
… Oil pump exclusively for cylinder head, V …… intake valve as engine valve

Continued on the front page (72) Inventor Kazuhide Kumagai 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside the Honda R & D Co., Ltd. (72) Takashi Yokoi 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside the research laboratory (72) Inventor Eizou Kaiyama 1-4-1 Chuo, Wako-shi, Saitama Prefecture Honda Technical Research Institute Co., Ltd. (56) References JP-A-61-275516 (JP, A) JP-A-57-116114 ( JP, A) JP-A-1-275974 (JP, A) JP-A-63-138407 (JP, U) JP-A-64-21204 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , (DB name) F01L 13/00 301 F01L 1/34 F01M 1/02 F16K 15/00

Claims (6)

(57) [Claims] An operating mode of said engine valve (V) between a crankshaft and an engine valve (V) operably supported by a cylinder head (9) in response to a change in hydraulic pressure in a hydraulic chamber (31). In a valve operating device for an internal combustion engine provided with a variable valve operation mode changing means (15), the valve operation mode changing means (15) includes: a cylinder body (34) fixed to a cylinder head (9); A cam driven piston (36) slidably fitted to the upper part of the cylinder body (34) while being linked to and connected to a valve operating cam shaft (26) connected to a crankshaft; and an engine valve (V). A valve drive piston (37) slidably fitted to the lower part of the cylinder body (34) while being connected thereto, and a valve drive piston (37) inside the cylinder body (34) for mutually transmitting the operations of the pistons (36, 37). With both pistons (36,3
7) hydraulic chamber is formed between the (31), and a hydraulic pressure releasing valve (44) connected to said hydraulic chamber (31), the oil supply passage leading to the oil pump (P, P _C) (3, 13 ), A valve drive piston (37) in a closed state of the engine valve (V) is provided at an intermediate portion of a branch oil passage (16) for valve operation mode changing means connected to the hydraulic chamber (31) while being branched from the hydraulic chamber (31). and higher the higher portion than the horizontal line (L) passing through the lowermost position of the sliding portion of the cylinder body (34) and (16b _U), the hydraulic pressure of said higher portion and lower than the horizontal line (L) (16b _U) A valve train for an internal combustion engine, comprising: a lower portion (16b _D ) connected to an end of the chamber (31). 2. The oil pump (P _C ) is an oil pump dedicated to a cylinder head (9) that is disposed on the cylinder head (9) to pump hydraulic oil from an oil bath (10) provided on the cylinder head (9). The valve train of an internal combustion engine according to claim 1, wherein: 3. An oil supply passage connected to the cylinder head dedicated oil pump (P _C ) at each lubricating portion of a valve train including a valve train camshaft (26) connected to a crankshaft and a valve operation mode changing means (15). The valve train of an internal combustion engine according to claim 2, wherein a lubricating branch oil passage (20) branched from (13) is connected. 4. A valve operating mode changing means (15) bypasses an accumulator (45) and the hydraulic pressure release valve (44) interposed between the accumulator (45) and the hydraulic chamber (31). A one-way valve interposed between the accumulator (45) and the hydraulic chamber (31) to open only at a set valve opening pressure and allow only the flow of hydraulic oil to the hydraulic chamber (31). (46) and a check valve (47) connected between the accumulator (45) and the one-way valve (46) to allow only the flow of hydraulic oil to the one-way valve (46) and the accumulator (45). ), And is branched from the oil supply path (3, 13) connected to the oil pump (P, P _C ) while being connected to the check valve (47) while being branched from the oil supply path (3, 13). 4. The valve train of an internal combustion engine according to claim 1, wherein a pressure regulating valve (14) is interposed. 5. A transmission mechanism (30) comprising said pistons (36, 37) and a cylinder body (34), and said hydraulic release valve (4).
And (4) are individually arranged corresponding to the plurality of engine valves (V), respectively, and the accumulator (45) is arranged commonly to the plurality of transmission mechanisms (30). Item 5. A valve train for an internal combustion engine according to item 4. 6. A branch oil passage (16) for said valve operation mode changing means.
Between the hydraulic chamber (31) and the hydraulic chamber (31), the hydraulic oil flows from the branch oil passage (16) for the valve operating mode changing means to the hydraulic chamber (31) when the hydraulic pressure difference between the hydraulic chamber and the hydraulic chamber (31) becomes a predetermined value or more. The valve train of an internal combustion engine according to claim 1, 2, or 3, wherein a plurality of one-way valves (46, 46) are provided in parallel with each other to allow circulation.