JP6718304B2 - Internal combustion engine valve device and internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulically driven valve operating device that hydraulically controls opening and closing of a valve in an internal combustion engine, and an internal combustion engine including the valve operating device.

BACKGROUND ART Conventionally, a hydraulic valve operating device has been used as a valve operating device that opens and closes intake and exhaust valves of an internal combustion engine that is used at a relatively low rotational speed used in ships and the like. The hydraulic valve operating device has the advantages that the operating noise is lower than that of the mechanical valve operating device, less oil is scattered during operation, and the inboard environment can be kept clean. As an example of such a hydraulically driven valve operating device, those described in Patent Documents 1 to 3 are known.
The valve operating device of the internal combustion engine described in Patent Document 1 has a mechanism for connecting the hydraulic chamber of the driving hydraulic piston device and the hydraulic chamber of the passive hydraulic piston device with the first fluid passage, the oil communication pipe, and the second fluid passage. I have it. The VVT control valve selectively discharges the lubricating oil in the second fluid passage to the outside to change the operation of the valve.

Further, the exhaust valve drive device described in Patent Document 2 has a hydraulic path that connects the first cylinder and the second cylinder, and a communication hole is formed in the plunger that slides in the second cylinder. There is. A hydraulic oil discharge path for discharging hydraulic oil is connected to a groove on the side surface of the second cylinder connected to the communication hole, and a discharge amount adjusting valve is provided in the hydraulic oil discharge path.
Further, in Patent Document 3, an accumulator that suppresses the pressure fluctuation of the hydraulic oil is provided between the cam side cylinder and the valve side cylinder.

Further, in the conventional hydraulic drive valve system 100 shown in FIG. 7, a drive cylinder 103 that slidably accommodates a drive hydraulic piston 102 pushed by a cam 101 and a passive hydraulic piston 105 that opens and closes an intake/exhaust valve 104 are provided. The stored passive cylinder 106 is connected by a hydraulic circuit 107. A check valve 108 for supplying new hydraulic oil from the engine body is installed on the upstream side of the hydraulic circuit 107, and a throttle valve is provided on the downstream side of the passive cylinder 106 as a control valve for opening and closing the hydraulic circuit 107 more easily. A flow control valve such as 109, a solenoid valve, a pilot check valve, or the like is installed.

If the intake/exhaust valve 104 is constantly operated in a closed system in the valve gear 100, there is a concern that the hydraulic oil may deteriorate early due to heat transfer from the intake/exhaust valve 104 and temperature rise due to friction due to the flow of hydraulic oil. .. In order to prevent this, when the intake/exhaust valve 104 is not lifted, the hydraulic circuit 107 is opened by the throttle valve 109 to discharge the heated hydraulic oil in the hydraulic circuit 107 and return it to the engine body to use the lubricating oil cooler. In addition to cooling, the working oil cooled from the engine body by the check valve 108 is supplied to the hydraulic circuit 107 for circulation.
In the throttle valve 109 described above, for example, as shown in FIGS. 8A and 8B, a valve body 112 is installed so as to be able to move forward and backward with respect to a tapered valve receiver 111. The valve body 112 is opened and closed by the hydraulic pressure in the hydraulic circuit 107 and the urging force of the valve spring 113, and the operating oil is sealed by the contact between the valve support 111 and the valve body 112. Then, when the valve is opened, the hydraulic oil is discharged through the orifice 112a provided in the throttle valve 109.

JP, 2014-29138, A JP, 2005-132192, A Japanese Utility Model Publication No. 59-58706

By the way, in the above-described conventional hydraulically operated valve operating system 100, the valve bearing 111 and the throttle valve 109 are worn due to long-term use of the throttle valve 109, and the valve bearing 111 and the throttle valve 109 are damaged due to foreign matter being caught. There was something to do. Further, in the solenoid valve or the like, the opening/closing mechanism of the hydraulic circuit sometimes fails due to electrical failure.

In view of such circumstances, it is an object of the present invention to provide a valve operating device and an internal combustion engine for an internal combustion engine, which can control opening and closing of a hydraulic circuit more easily without installing a control valve or the like. ..

A valve operating device for an internal combustion engine according to the present invention is a valve operating device for an internal combustion engine in which a valve is opened/closed by oil pressure of oil pressurized by a cam, and a drive piston reciprocated by a driven cam and a drive piston reciprocated. Connects a drive cylinder that changes the volume of hydraulic oil with a drive cylinder, a passive piston that opens and closes a valve by reciprocating, a passive cylinder that reciprocates the passive piston to change the volume of hydraulic oil, a drive cylinder and a passive cylinder A hydraulic transmission path for transmitting the hydraulic pressure of the hydraulic oil filled inside to the passive piston, and an operation for discharging the hydraulic oil from the hydraulic transmission path to the outside by being connected to a position near the passive piston in the hydraulic transmission path An oil discharge part is provided, and the hydraulic oil discharge part is opened and closed by the reciprocating movement of the passive piston.
According to the present invention, the drive piston is moved forward by the cam lift to compress the drive cylinder, thereby causing the hydraulic oil in the hydraulic pressure transmission path to flow to the passive cylinder side to increase the hydraulic pressure, and the heat-up operation is performed. By discharging the oil from the hydraulic oil discharge portion and operating the passive piston, valves such as intake and exhaust valves are opened, and the hydraulic oil discharge portion is closed by the operation of the passive piston. Then, when the lift of the cam is completed, the drive piston returns to the inside of the drive cylinder to reduce the hydraulic pressure in the hydraulic transmission path to open the hydraulic oil discharge portion by the return movement of the passive piston and close the valve. Therefore, the pressure control of the hydraulic pressure transmission path and the opening/closing operation of the valve by the cam can be performed without using a control valve such as a throttle valve or a solenoid valve. The hydraulic oil discharge portion is branched and connected to a position near the passive piston in the hydraulic pressure transmission path, and oil near the passive piston, which is easily affected by heat, is discharged. Here, "the position of the hydraulic transmission path near the passive piston" means a position relatively closer to the passive piston than the drive piston in the hydraulic transmission path, and preferably in the vicinity of the passive cylinder in the hydraulic transmission path. is there.

It is also preferable that the passive piston closes the hydraulic oil discharge portion when opening the valve.
By closing the hydraulic oil discharge portion when the passive piston opens the valve, the discharge of hydraulic oil from the hydraulic pressure transmission path can be stopped, the hydraulic pressure can be maintained, and the valve can be held in the open state.

Further, a hydraulic oil supply unit may be further provided which is connected to a position near the drive piston in the hydraulic pressure transmission path and supplies hydraulic oil according to the hydraulic pressure.
When the oil pressure in the hydraulic pressure transmission path increases, the hydraulic oil supply section is closed, and when the hydraulic pressure decreases, the hydraulic oil supply section is opened to supply hydraulic oil to the hydraulic pressure transmission path. Here, the “position near the drive piston in the hydraulic transmission path” means a position relatively closer to the drive piston than the passive piston in the hydraulic transmission path, and preferably in the vicinity of the drive cylinder in the hydraulic transmission path. Is.

Further, the passive piston may be formed with a discharge passage that can communicate with the hydraulic oil discharge portion, and the hydraulic oil may be discharged to the outside via the discharge passage.
When the hydraulic oil is discharged from the hydraulic oil discharge portion of the hydraulic pressure transmission path, the hydraulic oil is discharged to the outside via a discharge passage provided in the passive piston.

Further, an accumulator that stores excess hydraulic oil may be connected to the hydraulic pressure transmission path, the hydraulic oil discharge portion, or the hydraulic oil supply portion.
When the oil pressure in the hydraulic pressure transmission path is high, excess hydraulic oil is stored by the accumulator, and when the hydraulic pressure in the hydraulic pressure transmission path decreases at the end of the valve lift, the hydraulic oil in the accumulator is promptly transferred to the hydraulic pressure transmission path, hydraulic oil. Supply to the discharge part or hydraulic oil supply part to prevent negative pressure of hydraulic oil.

Further, it is preferable to provide a pressure loss portion that causes a pressure loss of the hydraulic oil in the hydraulic oil discharge portion.
When the hydraulic oil in the hydraulic transmission path is sent to the downstream side by the forward movement of the drive cylinder, the hydraulic oil is discharged at a high speed in the pressure loss section of the hydraulic oil discharge section and the pressure loss increases, and the hydraulic pressure in the hydraulic transmission path increases. Rise.

Further, it is preferable to provide a pressure loss portion in the discharge passage.
By using the discharge passage of the passive piston as the pressure loss portion, when the hydraulic oil passes through the discharge passage from the hydraulic oil discharge portion, the pressure loss increases and the hydraulic pressure in the hydraulic pressure transmission path can be increased.

Further, the pressure loss portion is preferably an orifice or a throttle portion that limits the flow rate of hydraulic oil.
The discharge flow rate of the hydraulic oil can be limited by forming the orifice in the hydraulic oil discharging portion. Further, by making the equivalent diameter of the discharge passage of the passive piston relatively smaller than the inner diameter of the hydraulic oil discharge portion of the hydraulic pressure transmission passage, a high pressure loss occurs in the discharge passage. Therefore, the hydraulic pressure of the hydraulic pressure transmission path can be increased.

A valve operating device for an internal combustion engine according to the present invention is a valve operating device for an internal combustion engine in which a valve is opened and closed by hydraulic pressure of oil pressurized by a cam, and a drive piston reciprocating by a driven cam and a drive piston reciprocating. Connects a drive cylinder that changes the volume of hydraulic oil with a drive cylinder, a passive piston that opens and closes a valve by reciprocating, a passive cylinder that reciprocates the passive piston to change the volume of hydraulic oil, a drive cylinder and a passive cylinder And a discharge passage for discharging the hydraulic pressure of the hydraulic oil filled in the inside to the passive piston, and a discharge passage for discharging the hydraulic oil in the passive cylinder to the outside provided in the passive piston. It is characterized in that the discharge passage is opened and closed by reciprocal movement.
According to the present invention, the lift of the cam causes the drive piston to move forward to cause the hydraulic oil in the hydraulic pressure transmission passage to flow to the passive cylinder side to increase the hydraulic pressure, and the hydraulic oil whose temperature has been raised by heat transfer or the like is passively used as a drain. A valve such as an intake/exhaust valve is opened by discharging the gas from the discharge passage of the cylinder and operating the passive piston, and closing the discharge passage on the downstream side of the passive cylinder by the operation of the passive piston. Then, when the lift of the cam is completed, the drive piston returns to the inside of the drive cylinder to lower the hydraulic pressure in the hydraulic pressure transmission path to open the discharge passage and close the valve by the return movement of the passive piston. Therefore, it is possible to open/close the hydraulic transmission path and open/close the valve with the cam without using a control valve such as a throttle valve or a solenoid valve.

The present invention is an internal combustion engine equipped with any one of the valve operating devices described above.
Gas exchange in the combustion chamber can be performed by opening/closing a valve that is an intake/exhaust valve of the combustion chamber by the valve operating device.

According to the valve operating device and the internal combustion engine of the present invention, the drive piston is moved forward to compress the drive cylinder, thereby increasing the hydraulic pressure of the hydraulic oil in the hydraulic transmission path and increasing the temperature by heat transfer or the like. It is possible to discharge the thus-operated hydraulic oil as a drain from the hydraulic oil discharge section, further close the hydraulic oil discharge section by the operation of the passive piston, and open a valve such as an intake/exhaust valve. Further, the drive piston can be returned to lower the hydraulic pressure in the hydraulic pressure transmission path, and the return of the passive piston can open the hydraulic oil discharge portion and close the valve.
Therefore, it is possible to open/close the hydraulic transmission path and open/close the valve with the cam without using a control valve such as a throttle valve or a solenoid valve.

According to the valve operating system and the internal combustion engine of the present invention, the drive piston is moved forward to increase the hydraulic pressure of the hydraulic oil in the hydraulic transmission path, and the hydraulic oil whose temperature is raised by heat transfer or the like is used as a drain. It is possible to discharge from the discharge passage of the piston, further close the discharge passage by the operation of the passive piston, and open valves such as intake and exhaust valves. Further, the drive piston can return to lower the hydraulic pressure in the hydraulic pressure transmission path, and the return path of the passive piston can open the discharge passage and close the valve. Therefore, it is possible to open/close the hydraulic transmission path and open/close the valve with the cam without using a control valve such as a throttle valve or a solenoid valve.

FIG. 1 is a diagram showing a main part configuration of a valve train for an internal combustion engine according to a first embodiment of the present invention. (A), (b), (c), (d) is a figure which shows the operation process of the valve operating apparatus shown in FIG. It is a figure which shows the principal part structure of the valve operating system of the internal combustion engine by 2nd embodiment of this invention. It is a figure which shows the principal part structure of the valve operating system of the internal combustion engine by 3rd embodiment of this invention. FIG. 11 is a diagram showing a main configuration of a valve train for an internal combustion engine according to a fourth embodiment of the present invention. FIG. 6 is a perspective view showing a passive hydraulic piston of the valve operating device shown in FIG. 5. It is a figure which shows the principal part structure of the valve operating device by the conventional hydraulic drive. It is a figure which shows the throttle valve of the valve operating apparatus shown in FIG. 7, (a) is a valve open state, (b) is a figure which shows a valve closed state.

Hereinafter, a valve train for an internal combustion engine according to each embodiment of the present invention will be described with reference to FIGS. 1 to 5.
1 and 2 show a valve train for an internal combustion engine according to a first embodiment of the present invention. The valve gear 1 shown in FIG. 1 is, for example, a hydraulically driven valve gear for a marine diesel engine. The valve gear 1 includes a drive hydraulic piston means 3 for transmitting the rotation of an intake cam 2 or an exhaust cam (hereinafter simply referred to as a cam 2) and a passive hydraulic piston means 5 for opening and closing an intake valve (or an exhaust valve) 4. , Are connected by a hydraulic flow path 6 filled with hydraulic oil.

The driving hydraulic piston means 3 has a driving cylinder 9 formed in a roller guide case 8, and a driving hydraulic piston 10 is fitted in the driving cylinder 9 so as to reciprocate by sliding. A roller guide 12 is fixed to a lower end portion of a rod 11 of the drive hydraulic piston 10, and a cam 2 is in contact with the roller guide 12 so that the drive hydraulic piston 10 can be pushed up during a lift, that is, when the cam portion comes into contact. Has been done. The drive cylinder 9 can increase or decrease the volume of the internal space 9a filled with hydraulic oil by moving the drive hydraulic piston 10 up and down.
The drive cylinder 9 is connected to the hydraulic flow passage 6, and a hydraulic oil supply pipe 14 is connected in the hydraulic flow passage 6 in the vicinity of the connection portion with the drive cylinder 9. A check valve 15 is installed in the hydraulic oil supply pipe 14, and the hydraulic oil supply pipe 14 and the check valve 15 constitute a hydraulic oil supply unit. When the hydraulic pressure in the hydraulic passage 6 decreases, the check valve 15 is opened to supply the cooled hydraulic oil from the engine body (not shown).

In the passive hydraulic piston means 5, a passive cylinder 18 filled with hydraulic oil is formed in the valve operating case 17, and a passive hydraulic piston 20 is slidably fitted in the passive cylinder 18 so as to reciprocate. ing. An intake valve (or an exhaust valve) 4 is connected to the lower end of the rod 21 of the passive hydraulic piston 20. When the cam 2 is lifted, the drive hydraulic piston 10 rises and the passive hydraulic piston 20 descends to open the intake valve 4. At the end of the lift of the cam 2, the drive hydraulic piston 10 descends and the passive hydraulic piston 20 rises to close the intake valve 4. A valve spring 23 that biases the passive hydraulic piston 20 in the upward valve closing direction is attached to the intake valve 4 in a compressed state. The passive cylinder 18 can increase or decrease the volume of the internal space 18a filled with hydraulic oil by moving the passive hydraulic piston 20 up and down.

Further, the hydraulic passage 6 is connected to the passive cylinder 18 on the downstream side of the hydraulic oil supply pipe 14, and a drain discharge passage 25 that is branched from the passive cylinder 18 is formed. The drain discharge passage 25 extends to a thick portion on the side of the passive cylinder 18 in the valve operating case 17, and a discharge port 25a for discharging hydraulic oil is opened in a wall surface of a drain chamber 28 below the passive cylinder 18. doing. An orifice 26 for narrowing the inner diameter of the flow path is attached to the discharge port 25a.
When the cam 2 is not lifted, excess hydraulic oil is discharged as drain from the orifice 26. This drain is recovered from the drain chamber 28 via a drain pipe (not shown), cooled and returned to the engine body. An accumulator 27 is connected in the middle of the drain discharge path 25. The accumulator 27 has at least a piston 30 and a spring 31 that partition an oil chamber 29 that communicates with the drain discharge passage 25 in the space and accumulates hydraulic oil. Is contained in the oil chamber 29, accumulated and released when the pressure becomes low.
The hydraulic flow path 6 is a flow path that physically connects the drive cylinder 9 and the passive cylinder 18, but more specifically, the flow path provided on the roller guide case 8 itself and the roller. It is composed of piping connecting the guide case 8 and the valve operating case 17, and a flow path provided in the valve operating case 17 itself.

The valve gear 1 according to the present embodiment has the above-described configuration, and its operation will be described next with reference to FIG.
In FIG. 2A, the passive hydraulic piston 20 stands still above the orifice 26 provided in the drain discharge passage 25, and the intake valve 4 is closed. At this time, the passive hydraulic piston 20 is located above the orifice 26. When the cam 2 rotates to start the lift, the drive hydraulic piston 10 is pushed to start the lift. Then, excess hydraulic oil having a high temperature is discharged from the orifice 26 as drain.

As the drive hydraulic piston 10 rises, hydraulic oil flows in the hydraulic passage 6 and the drain discharge passage 25 from the cam 2 side to the orifice 26 side. The flow rate of the hydraulic oil increases when it is discharged into the drain chamber 28 through the orifice 26, and the pressure loss when discharging the hydraulic oil from the orifice 26 as a drain increases. Therefore, the pressure in the hydraulic passage 6 and the drain discharge passage 25 increases. The check valve 15 closes due to the increase of the hydraulic oil pressure in the hydraulic flow path 6, and the flow of the hydraulic oil into the hydraulic flow path 6 is stopped.
Further, the accumulator 27 causes the hydraulic oil to resist the urging force of the spring 31 by increasing the pressure of the hydraulic oil from the non-lifted state of the cam 2 in the previous stage (the state in which the drive hydraulic piston 10 is not pushed). It is in a charged state stored in 29.

Next, as shown in FIG. 2B, the intake cam 2 lifts the drive hydraulic piston 10 to further increase the hydraulic oil pressure in the hydraulic passage 6. When the force (valve opening force) that pushes the passive hydraulic piston 20 due to the hydraulic oil pressure in the passive hydraulic piston means 5 exceeds the biasing force (load) of the valve spring 23 and the force that pushes the intake valve 4, the passive hydraulic piston 20 and The intake valve 4 starts to lift (fall), and the intake valve 4 starts to open in the combustion chamber 22.

Then, in FIG. 2C, when the lower portion of the passive hydraulic piston 20 moves below the position of the orifice 26 due to the increase in the lift amount of the passive hydraulic piston 20 and the intake valve 4, the orifice 26 is closed by the passive hydraulic piston 20. It Then, the outflow of the hydraulic oil from the drain discharge path 25 is stopped, and the valve opening lift is continued without the hydraulic pressure in the hydraulic pressure passage 6 being lowered, so that the intake valve 4 is held in the open state. On the other hand, when the lift of the drive hydraulic piston 10 by the cam 2 is completed, the flow of the hydraulic oil stops, and the pressure of the hydraulic oil becomes uniform in the hydraulic passage 6.

After that, as shown in FIG. 2D, when the lift ends, the drive hydraulic piston 10 descends and the hydraulic pressure decreases. Further, the passive hydraulic piston 20 is pushed back by the urging force of the valve spring 23, and the intake valve 4 is closed. After the lift is completed, the drive hydraulic piston 10 is lowered and the hydraulic pressure in the hydraulic flow path 6 is lowered. Therefore, the check valve 15 is opened to supply the working oil, and the hydraulic pressure is raised to the original state to be in the initial state. Return to.
The hydraulic oil in the hydraulic flow passage 6 and the drain discharge passage 25 is likely to be deteriorated early due to a temperature increase due to heat transfer from the intake/exhaust valve and friction caused by its own flow. However, the high-temperature drain discharged from the orifice 26 returns from the drain chamber 28 to the engine body via a drain pipe (not shown) and is cooled by a lubricating oil cooler (not shown). After that, the hydraulic oil is delivered by an oil pump (not shown) and is circulated by being supplied to the hydraulic flow passage 6 from the check valve 15 to suppress early deterioration.

Further, since the valve gear 1 according to the present embodiment has the accumulator 27 installed in the drain discharge passage 25, the hydraulic flow passage 6 and the drain discharge passage are formed between the start of the lift of the cam 2 and the end of the lift of the intake valve 4. Since the hydraulic pressure in 25 rises, a part of the hydraulic oil is stored (charged) in the oil chamber 29 of the accumulator 27.
After the lift is completed, when the hydraulic pressure in the hydraulic flow passage 6 and the drain discharge passage 25 decreases due to the descent of the drive hydraulic piston 10 in the drive cylinder 9, the check valve 15 opens and then the hydraulic flow passage When the recovery of the operating oil pressure in 6 is delayed, the oil pressure in the oil pressure passage 6 becomes a negative pressure, causing cavitation. In order to prevent this, the hydraulic oil of relatively high pressure charged by the accumulator 27 when the hydraulic pressure in the hydraulic pressure passage 6 and the drain discharge passage 25 decreases is promptly discharged into the hydraulic flow passage 6 and the drain discharge passage 25. To be done.
As a result, the negative pressure of the hydraulic pressure in the hydraulic pressure passage 6 and the drain discharge passage 25 at the time when the lift of the intake valve 4 is completed can be suppressed.

When the accumulator is not installed, the intake valve (or the exhaust valve) 4 is biased in the valve closing direction when the cam 2 is not lifted due to overload operation or the like. The intake (exhaust) air valve 4 may lift at an unintended timing due to an imbalance in intake (exhaust) air pressure. In this case, hydraulic oil flows in from the check valve 15 in order to fill the volumes of the drain discharge passage 25 and the hydraulic flow passage 6 that have expanded due to the lowering of the passive hydraulic piston 20. As a result, the volume of the hydraulic oil becomes larger than the volumes of the drain discharge passage 25 and the hydraulic flow passage 6 when the intake (exhaust) air valve 4 is not lifted, so that the intake (exhaust) air valve 4 is lifted. After that, it becomes difficult to close the valve again.
On the other hand, when the accumulator 27 is provided, even if the intake (exhaust) air valve 4 is lifted at an unintended timing, the hydraulic oil charged in the accumulator 27 is transferred to the drain discharge passage 25 and the hydraulic passage 6. By discharging to the check valve 15, the inflow of hydraulic oil from the check valve 15 can be suppressed. Further, even if the volume of the hydraulic oil is excessive when the intake (exhaust) air valve 4 is seated, the excess hydraulic oil re-flows into the accumulator 27, thereby avoiding poor seating of the intake (exhaust) air valve. it can.

As described above, according to the valve operating system 1 of the present embodiment, the passive hydraulic piston that opens and closes the hydraulic passage 6 moves up and down with the orifice 26 of the drain discharge passage 25 attached to the wall surface of the drain chamber 28 below the passive cylinder 18. It is carried out by the mutual position with the valve 20, and unlike the conventional valve seat and valve body of the throttle valve, there is no metal touch, so that the seat surface is not consumed. As a result, it is possible to achieve stable operation of the opening/closing functions of the hydraulic flow path 6 and the drain discharge path 25 and to prolong the service life thereof.

Further, since one drain chamber 28 can collect both the drain discharged from the orifice 26 of the drain discharge path 25 and the drain leaking from the fitting gap between the passive cylinder 18 and the passive hydraulic piston 20, the valve operating device 1 The manufacturing cost can be reduced, and the piping can be designed more easily.
Further, since the drain is discharged from the orifice 26 to the drain chamber 28 following the passive cylinder 18, the hydraulic oil is directly injected into the fitting portion of the passive hydraulic piston 20 and the passive cylinder 18 when the orifice 26 is closed by the passive hydraulic piston 20. .. As a result, good lubricity of the passive hydraulic piston 20 can be obtained, galling and burnout of the passive hydraulic piston 20 are prevented, and reliability is improved.

The present invention is not limited to the valve operating system 1 according to the first embodiment described above, and can be appropriately changed or replaced without changing the gist of the present invention. include. Next, other embodiments and modified examples of the present invention will be described, but the same or similar parts and members as those of the above-described embodiment will be described using the same reference numerals.

FIG. 3 shows a valve train 1A according to a second embodiment of the present invention.
The valve gear 1A shown in FIG. 3 has a structure that reduces the drainage discharged into the valve gear case 17. The second embodiment is different from the valve operating system 1 according to the first embodiment in that the orifice 26 is provided on the inner wall surface of the passive cylinder 18 so as to face the side surface of the passive hydraulic piston 20 in the non-lift position (rest position). Set. Then, an oil groove portion 35 for drain discharge is formed as a discharge passage on the entire outer peripheral surface of the passive hydraulic piston 20 having the same height. Further, in the valve operating case 17, another drain discharge hole 36 is provided at the same height position on the other inner wall surface facing the orifice 26 provided on the inner wall surface of the passive cylinder 18, and the discharge port is opened radially outward. It was

Therefore, in the valve gear 1A according to the second embodiment, the passive hydraulic piston 20 in the non-lift position (rest position) is discharged from the orifice 26 via the hydraulic flow path 6 and the drain discharge path 25 when the cam 2 is lifted. The drain is discharged to the outside from the drain discharge hole 36 through the oil groove portion 35 of the passive hydraulic piston 20. As a result, the amount of drain that drops into the valve operating case 17 can be reduced, and even if the orifice 26 has a large diameter and the amount of drain is large, it is possible to prevent an excessive amount of oil from being injected into the valve stem of the intake/exhaust valve.
Then, the lift of the cam 2 raises the drive hydraulic piston 10 and the hydraulic pressure in the hydraulic passage 6 rises, so that the passive hydraulic piston 20 lifts (falls) together with the intake valve 4, so that the oil groove portion 35 moves from the orifice 26. It is displaced and closed on the side surface of the passive hydraulic piston 20. Therefore, the outflow of hydraulic oil from the drain discharge passage 25 is stopped, and the intake valve 4 is held in the open state. Then, the lift of the drive hydraulic piston 10 by the cam 2 is completed, and the pressure of the hydraulic oil is uniformly held in the hydraulic passage 6.

FIG. 4 shows a valve train 1B according to a third embodiment of the present invention.
The valve gear 1B shown in FIG. 4 has a structure that reduces the drainage discharged into the valve gear case 17. In the third embodiment, the discharge port 25a of the drain discharge passage 25 is not provided with the orifice 26, and the cross-sectional area of the oil groove portion 35 formed on the outer peripheral surface of the passive hydraulic piston 20 in the second embodiment is discharged from the drain discharge passage 25. It was set smaller than the cross-sectional area of the outlet 25a. The oil groove portion of the present embodiment is shown by reference numeral 38. As a result, a pressure loss equivalent to that of the orifice 26 can be exhibited. Further, the drain discharge hole 39 is formed below through the thick portion of the valve operating case 17 so as to be discharged to the outside. Alternatively, the same structure as the drain discharge hole 36 described above may be adopted.
Moreover, the discharge port 25a of the drain discharge passage 25 communicates with the oil groove portion 38 formed at the position of the passive hydraulic piston 20 in the non-lifted state (stationary state) at the same height, and the inlet 39a of the drain discharge hole 39 also has the discharge port 25a. It was installed at the same height as.

Therefore, when the hydraulic oil flowing through the hydraulic flow passage 6 when the cam 2 is lifted flows from the discharge port 25a of the drain discharge passage 25 to the oil groove portion 38 having a relatively small diameter of the passive hydraulic piston 20, the flow velocity of the drain increases, resulting in a pressure loss. Since the pressure increases, the hydraulic pressure of the hydraulic oil in the hydraulic flow path 6 increases. The hydraulic oil passing through the drain discharge hole 39 from the oil groove portion 38 is discharged to the outside as a drain. Further, when the hydraulic pressure in the hydraulic passage 6 rises, the passive hydraulic piston 20 is lifted.
In the structure using the orifice 26 of the above-described embodiment, the pressure loss is adjusted by adjusting the orifice diameter, but in the third embodiment, the passive cylinder is used with respect to the cross-sectional area of the discharge port 25a of the drain discharge passage 25. The pressure loss can be adjusted by designing the cross-sectional shape of the oil groove 38 with the equivalent edge diameter obtained from the wetting edge length and the cross-sectional area of the flow passage cross section formed by the inner wall surface of 18 as the objective function. In this case, the oil groove portion 38 forms the throttle portion of the drain discharge passage 25.

Next, FIG. 5 shows a valve gear 1C according to a fourth embodiment of the present invention.
The valve gear 1C shown in FIG. 5 also has a structure that reduces drainage discharged into the valve case 17. In the fourth embodiment, in the passive hydraulic piston 20 slidable in the passive cylinder 18 provided in the valve operating case 17, the internal space 18a filled with the working oil of the passive cylinder 18 and the side surface of the passive hydraulic piston 20 are provided. The drain communication passage 42 that opens at the center is formed in a substantially inverted T-shape in cross section. Further, the drain discharge hole 36 having the inlet is provided on the wall surface of the passive cylinder 18 facing the horizontal portion of the drain communication passage 42 opening to the side surface of the passive hydraulic piston 20 in the non-lifted state (stationary state).

FIG. 6 shows the structure of the passive hydraulic piston 20 in this embodiment. The drain communication passage 42 has a vertical portion 42a that opens to the upper end surface of the passive hydraulic piston 20, a horizontal portion 42b that communicates with the vertical portion 42a and opens to the side surface, and a peripheral surface of the passive hydraulic piston 20 at a position that communicates with the horizontal portion 42b. It is configured by a groove portion 42c having a substantially semicircular cross section, which is cut into a groove shape over the entire circumference. Therefore, even if the passive hydraulic piston 20 rotates in the passive cylinder 18 around the central axis of the passive cylinder 18, the drain is drained.

Therefore, in the valve gear 1C according to the present embodiment, the hydraulic fluid flowing through the hydraulic flow passage 6 has a higher flow velocity when flowing into the drain communication passage 42 of the passive hydraulic piston 20 from the passive cylinder 18, which increases pressure loss. The pressure in the hydraulic passage 6 increases. The hydraulic oil passing through the drain communication passage 42 and the drain discharge hole 36 is discharged to the outside as drain. The flow rate of the working oil flowing through the drain communication passage 42 of the passive hydraulic piston 20 is increased by the lift of the drive hydraulic piston 10, and the hydraulic pressure is increased by the increase of the pressure loss to lift the passive hydraulic piston 20.

In addition, in the fourth embodiment, the drain discharge passage 25 is provided on the downstream side of the passive cylinder 18 in the hydraulic flow passage 6, but the drain discharge passage 25 may not be provided. In this case, the accumulator 27 may be connected to the hydraulic passage 6. Alternatively, in the valve trains 1, 1A, 1B, 1C according to the above-described embodiments, the accumulator 27 may be connected to the drain passage 25 in the vicinity of the check valve 15 on the downstream side of the check valve 15 instead of the drain discharge passage 25. In this case, the negative pressure of the hydraulic pressure can be prevented by discharging the hydraulic oil of the accumulator 27 into the hydraulic pressure passage 6 in which the hydraulic pressure has decreased after the lift is completed. Further, the release of the hydraulic oil from the accumulator 27 can suppress the valve opening operation of the check valve 15, and can suppress the excessive hydraulic oil from flowing into the hydraulic passage 6. The accumulator 27 may be installed both in the drain discharge passage 25 and the hydraulic passage 6, or in the hydraulic passage 6 near the drive cylinder 9 and the passive cylinder 18, respectively.

In the present invention, the accumulator 27 does not necessarily have to be installed.
The hydraulic pressure transmission path in the present invention is represented by the hydraulic pressure flow path 6, but is not limited to this. A portion of the upper portion of the passive cylinder 18 that does not overlap with the upward movement of the passive hydraulic piston 20 and a portion of the upper portion of the drive cylinder 9 that does not overlap with the upward movement of the driving hydraulic piston 10 also function as hydraulic transmission paths. The hydraulic transmission path includes these. Therefore, a hydraulic oil discharge part and a hydraulic oil supply part may be connected to these parts, respectively.
The drain discharge passage 25 and the discharge port 25a are included in the hydraulic oil discharge portion.
The drive hydraulic piston 10 is included in the drive piston, and the passive hydraulic piston 20 is included in the passive piston. The oil groove portions 35, 38 and the drain communication passage 42 of the passive hydraulic piston 20 form a discharge passage, and the orifice 26, the oil groove portion 38, and the drain communication passage 42 are included in the pressure loss portion.

1, 1A, 1B, 1C Valve device 2 Cam 4 Intake valve 6 Hydraulic flow path 9 Drive cylinder 10 Drive hydraulic piston 15 Check valve 18 Passive cylinder 20 Passive hydraulic piston 25 Drain discharge passage 26 Orifice 27 Accumulator 35, 38 Oil groove part 36, 39 Drain discharge hole 42 Drain communication passage

Claims (10)

In a valve operating system of an internal combustion engine, which opens and closes a valve by hydraulic pressure of oil pressurized by a cam,
A drive piston that reciprocates by the cam that is driven,
A drive cylinder that reciprocates the drive piston to change the volume of hydraulic oil;
A passive piston that opens and closes the valve by reciprocating;
A passive cylinder that reciprocates the passive piston to change the volume of hydraulic oil;
A hydraulic pressure transmission path that connects the drive cylinder and the passive cylinder and transmits the hydraulic pressure of the hydraulic oil filled therein to the passive piston;
And a hydraulic fluid discharge portion for discharging the working oil to the outside from the hydraulic transmission path is connected to the position of the passive piston closer in the hydraulic transmission path,
A valve operating system for an internal combustion engine, wherein the hydraulic oil discharge portion is opened and closed by the reciprocating movement of the passive piston. The valve operating system for an internal combustion engine according to claim 1, wherein the passive piston closes the hydraulic oil discharge portion when the valve is opened. The valve operating system for an internal combustion engine according to claim 1 or 2, further comprising a hydraulic oil supply unit that is connected to a position near the drive piston in the hydraulic pressure transmission path and supplies hydraulic oil. 4. The passive piston is formed with a discharge passage that can communicate with the hydraulic oil discharge portion, and the hydraulic oil is discharged to the outside through the discharge passage. Valve device for an internal combustion engine. The valve operating device for the internal combustion engine according to any one of claims 1 to 4, wherein an accumulator for storing excess hydraulic oil is connected to the hydraulic pressure transmission path, the hydraulic oil discharge portion, or the hydraulic oil supply portion. .. The valve operating system for an internal combustion engine according to claim 1, wherein a pressure loss portion that causes a pressure loss of the hydraulic oil is provided in the hydraulic oil discharge portion. The valve operating system for an internal combustion engine according to claim 4, wherein a pressure loss portion is provided in the discharge passage. The valve operating system for an internal combustion engine according to claim 6 or 7, wherein the pressure loss portion is an orifice or a throttle portion that limits a flow rate of the hydraulic oil. In a valve operating system of an internal combustion engine, which opens and closes a valve by hydraulic pressure of oil pressurized by a cam,
A drive piston that reciprocates by the cam that is driven,
A drive cylinder that reciprocates the drive piston to change the volume of hydraulic oil;
A passive piston that opens and closes the valve by reciprocating;
A passive cylinder that reciprocates the passive piston to change the volume of hydraulic oil;
A hydraulic transmission path that connects the drive cylinder and the passive cylinder and transmits the hydraulic pressure of the hydraulic oil filled inside to the passive piston;
And a discharge passage provided in the passive piston for discharging the hydraulic oil in the passive cylinder to the outside,
A valve operating system of an internal combustion engine, wherein the exhaust passage is opened and closed by the reciprocating movement of the passive piston. An internal combustion engine comprising the valve operating device for an internal combustion engine according to claim 1.

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