JP4523559B2 - Engine valve drive - Google Patents

Description

  The present invention relates to an intake / exhaust valve (intake valve / exhaust valve) that exchanges gas in a cylinder of an internal combustion engine or a drive device that drives a fuel injection valve that supplies fuel into a cylinder of the internal combustion engine.

Conventionally, for example, a drive device for an intake / exhaust valve is disclosed in Patent Document 1. In this technique, a gas valve provided in front of an inlet valve of a combustion chamber of a gas engine is moved between a position where gas flow is blocked and a position where gas is flowed. The driving device has a working chamber between the upper and lower side of the piston, when moving the gas valve from the shutoff position to the inlet position, supplies pressure oil to the working chamber of the upper piston. As a result, the gas valve moves to the inflow position against the return force of the return spring provided on the lower side of the piston. At this time, the oil in the upper working chamber is returned to the tank. When returning the gas valve from the inflow position to the shut-off position, the upper working chamber of the piston is connected to a return pipe that leads to the tank. As a result, the piston starts to move back to the blocking position by the return force of the return spring. At this time, the lower working chamber of the piston is filled with pressure oil, and the oil in the lower working chamber of the piston is taken in and out through an intermediate hole communicating with the lower working chamber.

Japanese Patent Laid-Open No. 9-151715

  In this drive device, the oil in the working chamber below the piston is simply put in and out of the lower working chamber without being returned to the tank. The gas valve is provided in the cylinder head portion of the internal combustion engine, and the vicinity of the cylinder head portion is at a high temperature. Moreover, if it is exposed to high temperature too much, the oil will boil and air bubbles may be generated in the oil. If the valve is continuously operated in such a state, there is a risk of causing malfunction or failure.

  An object of the present invention is to provide an engine valve drive device that is less prone to malfunction and failure.

The valve drive device for an engine according to one aspect of the present invention exchanges gas in a cylinder of the internal combustion engine or supplies fuel to the cylinder of the internal combustion engine, and includes a spring that presses the valve in the closing direction. ing. Furthermore, a cylinder tube of a hydraulic cylinder is provided, and a piston is partitioned into first and second chambers in the cylinder tube. A rod is fixed to the piston and connected to the valve. A supply passage can supply pressure oil to the first chamber. The first discharge passage can discharge oil from the first chamber. A stopper chamber is defined by the piston in the second chamber when the valve is opened. The second discharge passage can discharge oil from the second chamber to the tank . The first discharge passage is connected to the second chamber, and a control valve is disposed in the first discharge passage. The control valve is closed when the pressure oil is supplied to the first chamber, and is opened when the oil is discharged from the first chamber. Note that the supply passage and the first discharge passage may be connected in parallel, and the supply passage and the first discharge passage may also be used for oil supply and discharge. In this case, the connection point connected in parallel is connected to the input side of the control valve and also connected to the pressure oil source.

  If comprised in this way, in a valve closing state, pressure oil will be supplied to a 1st chamber from a supply channel, and a piston will move, resisting the restoring force of a spring, and will open a valve. At this time, the oil in the second chamber is discharged through the second discharge passage. When the supply of the pressure oil in the first chamber is stopped in this valve open state, the piston moves in the closing direction by the return force of the spring, and the oil is discharged from the first discharge passage. At this time, the oil in the first discharge passage is supplied to the second chamber via the control valve in the open state. Accordingly, the oil in the second chamber is supplied from the first chamber when the valve is closed, and is discharged to a tank or the like when the valve is opened. Therefore, the oil is returned to the pressure oil source, circulates, and deteriorates the oil. In addition, it is possible to reduce malfunctions and failures due to oil deterioration.

  The stopper chamber can also be connected to the second discharge passage through a throttle. If comprised in this way, the oil of a stopper chamber will not be discharged | emitted rapidly, but a piston can be stopped in the buffered state.

Alternatively, a second discharge passage check valve that reverses the direction of the second chamber can be disposed in the second discharge passage. If comprised in this way, oil will not flow backward from the tank to which the 2nd discharge | emission channel | path is connected, but the oil of a 2nd chamber can be circulated efficiently.

  Alternatively, a check valve for a supply passage whose forward direction is the first chamber direction can be arranged in the supply passage. If comprised in this way, since all the oil discharged | emitted from the 1st chamber can be supplied to a 2nd chamber, the oil of a 2nd chamber can be circulated efficiently.

  As described above, according to the present invention, since the oil discharged from the first chamber is supplied to the second chamber and discharged from the second chamber, the oil is circulated. It is possible to make it difficult for malfunctions and failures to occur in the engine valve drive device.

  The engine valve drive apparatus according to the first embodiment of the present invention is for opening and closing a replacement valve 2 for exchanging gas in a cylinder of an internal combustion engine, for example, intake or exhaust, and has a cylinder tube 4. ing.

A piston 6 is disposed inside the cylinder tube 4 so as to be slidable along the length direction. The piston 6 divides the inside of the cylinder tube 4 into a first chamber 8 and a second chamber 10. The piston 6 faces the large-diameter portion 6a substantially matching the inner diameter of the cylinder tube 4, the small-diameter portion 6b on the side facing the first chamber 8 of the large-diameter portion 6a, and the second chamber 10 of the large-diameter portion 6a. And a small-diameter portion 6c on the side to be operated. A stopper chamber 12 is formed at the end of the cylinder tube 4 on the first chamber 8 side so that the small diameter portion 6b is completely fitted to stop the piston 6, and similarly, the end of the cylinder tube 4 on the second chamber 10 side is formed. A stopper chamber 14 for stopping the piston 6 by completely fitting the small diameter portion 6c is formed. When the small-diameter portion 6b or 6c of the piston 6 starts to fit into the stopper chamber 12 or 14, the cushion is surrounded by the cylinder tube 4, the stopper chamber 12 or 14, the large-diameter portion 6a and the small-diameter portion 6b of the piston 6. A chamber is formed.

  A rod 16 is coupled to the small diameter portion 6 c of the piston 6. The rod 16 passes through the second chamber 10, is led out of the cylinder tube 4, and is coupled to the above-described valve rod 2 a of the exchange valve 2 via the connecting portion 18. When the piston 6 is located in the stopper chamber 12 of the first chamber 8, the exchange valve 2 is closed, and when the piston 6 is located in the stopper chamber 14 of the second chamber 10, the exchange valve 2 is opened. It has been.

  The valve stem 2a is inserted through the fixed portion 20, and a spring, for example, a return spring 22 is disposed between the connecting portion 18 and the fixed portion 20 around the valve rod 2a. The return spring 22 presses the valve rod 2a in the closing direction, that is, in the first chamber 8 direction.

  A passage 24 through which pressure oil is supplied to and discharged from the first chamber 8 is connected to the first chamber 8, for example, the stopper chamber 12. The first chamber 8 is connected to a passage 26 for supplying and discharging oil. These passages 24 and 26 function as a supply passage and a first discharge passage. A parallel circuit of a check valve 28 and a flow rate adjusting means, for example, a throttle 30 is interposed in the passage 26. The check valve 28 can supply oil to the first chamber 8 side, but the first chamber 8 side is set in the forward direction so as to prevent the oil from being discharged from the first chamber 8. In addition, the throttle 30 discharges oil contained in the cushion chamber when the above-described cushion chamber is formed. The passage 24 and the passage 26 are connected to each other and connected to a control means such as an electromagnetic switching valve 36 through a high-pressure line 34 in which a check valve 32 is interposed. The check valve 32 prevents pressure oil from the electromagnetic switching valve 36 from flowing to the first chamber 8 side through the passage 24 and the passage 26 and prevents oil from the first chamber 8 from flowing to the electromagnetic switching valve 36. The first chamber 8 side is connected to the forward direction.

  The electromagnetic switching valve 36 selectively takes the first switching state and the second switching state. In the first switching state, the pressure oil source, for example, the pressure oil from the pump 38 is supplied to the high pressure line 34. In the second switching state, the high-pressure line 34 is connected to the tank 40.

  A connection point between the check valve 32 and the passage 24 and the passage 26 is connected to a passage 42 to the second chamber 10. In this passage 42, a flow rate adjusting means, for example, a throttle 44 and a control valve, for example, a pilot check valve 46 are connected in series in this order from the check valve 32 side. The pilot check valve 46 is connected to the second chamber 10 via a flow rate adjusting means, for example, a throttle 48 and directly connected to the stopper chamber 14. The pilot check valve 46 is arranged with the second chamber 10 side in the forward direction so as to flow oil from the throttle 44 side to the second chamber 10 side and prevent the oil from flowing in the reverse direction. Is configured to prevent oil from flowing to the second chamber 10 side when the pressure is a predetermined pressure, for example, a pressure when the electromagnetic switching valve 34 is switched to the first state. The check valve 48 is arranged with the second chamber 10 side in the forward direction so that oil flows from the pilot check valve 46 side to the second chamber 10 side and prevents oil from flowing in the reverse direction.

  The second chamber 10 and the stopper chamber 14 are connected to the tank 40 via a second discharge passage, for example, a discharge passage 50. The discharge passage 50 includes a flow rate adjusting means provided on the second chamber 10 side, such as a throttle 52, and a flow rate adjusting means provided on the stopper chamber 14 side, such as a throttle 54, which are connected via a check valve 56. Connected to the tank 40. The restrictor 54 is for discharging oil from the second chamber. The restrictor 52 discharges the oil contained in the cushion chamber when the above-described cushion chamber is formed. The check valve 56 is arranged with the tank 40 side in the forward direction so that oil flows from the throttles 52 and 54 side to the tank 40 side and prevents oil from flowing from the tank 40 side to the throttles 52 and 54 side. .

  In the valve drive device configured as described above, assuming that the valve 2 is in the closed state, the piston 6 is positioned on the cushion chamber 12 side of the cylinder tube 4 and the volume of the second chamber 10 is maximized. , There is a lot of oil. Further, it is assumed that the electromagnetic switching valve 36 is in the second state. In this state, when the electromagnetic switching valve 36 is switched to the first state, the pressure oil flowing through the high pressure line 34 from the pump 38 is supplied to the first chamber 8 via the check valve 32 and the passage 24. Further, the pressure oil is supplied to the first chamber 8 through the check valve 28. The pressing force of the piston 6 due to the pressure oil pressure at this time is larger than the return force of the return spring 22, and the piston 6 moves toward the stopper chamber 14 side while compressing the return spring 22 and starts to open the valve. To do. Since the pressure in the high pressure line 34 is applied to the pilot check valve 46, the pilot check valve 46 is closed, and no pressure oil is supplied to the second chamber 10.

At this time, the oil in the second chamber 10 is discharged to the tank 40 via the throttle 52 and the check valve 56. The moving speed of the piston 6 is adjusted by a throttle 54 that adjusts the flow rate of discharged oil. When the small-diameter portion 6c of the piston 6 begins fit into the stopper chamber 14, the cushion chamber is formed as described above, by the oil stop flow 54 flowing out from the cushion chamber to adjust the moving speed of the piston 6 is reduced And a cushioning action occurs. When the small diameter portion 6c is completely fitted into the stopper chamber 14, the piston 6 is stopped and the valve 2 is completely opened.

  In this valve open state, when the electromagnetic switching valve 36 is switched to the second state, the pressure in the high pressure line 34 decreases, and the piston 6 moves toward the stopper chamber 12 by the return force of the return spring 22 that is compressed. Start moving. As a result, oil is discharged from the passage 24. At this time, since the pressure in the high pressure line 34 is reduced, the pilot check valve 46 is opened, and oil can flow to the second chamber 10 side through the pilot check valve 46. Accordingly, the oil from the passage 24 is supplied to the second chamber 10 via the throttle 44 and the pilot check valve 46, and also supplied to the second chamber 10 via the check valve 48. The moving speed of the piston 6 at this time is adjusted by the diaphragm 44. In addition, since the check valve 32 is provided, the oil from the passages 24 and 26 does not flow to the electromagnetic switching valve 36 side.

  When the small-diameter portion 6b of the piston 6 begins to fit into the stopper chamber 12, a cushion chamber is formed, the flow rate of oil from the cushion chamber is adjusted by the throttle 30, cushion action is performed, and the small-diameter portion 6b is completely stopped. When fitted in the chamber 12, the piston 6 stops and the valve 2 is closed. Since the check valve 28 is provided, the oil in the passage 26 flows only on the throttle 30 side, and the cushioning action is effective. Further, since the check valve 56 is provided, the oil does not flow back from the tank 40 to the second chamber 10 when the oil is supplied to the second chamber 10 from the first chamber 8 side.

  Thus, in this drive device, when the piston 6 moves toward the stopper chamber 12 and closes, the oil discharged from the first chamber 8 is supplied to the second chamber 10, and the piston 6 When moving toward the stopper chamber 14 and closing the valve, the oil in the second chamber 10 is discharged to the tank 40. Since the oil in the tank 40 is supplied to the pump 38, the oil circulates eventually. Therefore, the oil supplied to and discharged from the second chamber 10 does not simply repeat entering and exiting the second chamber 10, and even if the valve 2 is provided near the cylinder head portion of the engine, it is not exposed to high temperatures. The deterioration of the oil is not promoted, and the oil does not boil, so that bubbles are not generated in the oil. As a result, valve malfunction and failure are less likely to occur.

  In the above embodiment, the oil supply / discharge to / from the first chamber 8 is performed using the passage 24 and the passage 26. However, the oil supply passage and the oil discharge passage are provided separately. You can also. In this case, the oil discharge passage is connected to a series circuit of the throttle 44 and the pilot check valve 46. Further, although the stopper chambers 12 and 14 are provided at both ends of the cylinder tube 4, only the stopper chamber 14 on the second chamber 10 side can be provided.

  The engine valve drive apparatus according to the second embodiment of the present invention is for a fuel injection valve that supplies fuel into a cylinder of an internal combustion engine. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. In the first embodiment, the valve driving device operates the exchange valve 2 that performs intake and exhaust, but in the second embodiment, the fuel injection valve 52 is operated via the measuring cylinder 51. Moreover, in 1st Embodiment, although it is a double rod type provided with the valve rod on the opposite side of the valve rod 16, in 2nd Embodiment, it is a single rod type only of the valve rod 16.

Similarly to the first embodiment, when the piston 6 moves toward the stopper chamber 12 to close the valve, the drive device of the second embodiment removes the oil discharged from the first chamber 8 into the second chamber 10. is supplied to the piston 6 when the closing moving toward the stopper chamber 14 side, and discharging oil in the second chamber 10 to the tank 40. Since the oil in the tank 40 is supplied to the pump 38, the oil circulates eventually. Therefore, the oil supplied to and discharged from the second chamber 10 does not simply repeat entering and exiting the second chamber 10, and even if the measuring cylinder 51 and the fuel injection valve 52 are provided in the vicinity of the cylinder head portion of the engine, the temperature is high. In other words, the oil is not deteriorated and the oil does not boil, so that bubbles are not generated in the oil. As a result, the malfunction and failure of the fuel injection valve 52 are less likely to occur.

1 is a hydraulic circuit diagram of a valve drive device according to a first embodiment of the present invention. It is a hydraulic-circuit figure of the drive device of the valve of 2nd Embodiment of this invention.

Explanation of symbols

2 Replacement Valve 2a Valve Rod 4 Cylinder Tube 6 Piston 8 First Chamber 10 Second Chamber 14 Stopper Chamber 24 26 Passage (Supply Passage, First Discharge Passage)
46 Pilot check valve (control valve)
50 Second discharge passage 51 Metering cylinder 52 Fuel injection valve

Claims (4)

A valve drive device for an engine used for a valve having a spring that performs gas exchange in a cylinder of an internal combustion engine or fuel injection into a cylinder of the internal combustion engine and presses in a closing direction,
A cylinder tube of a hydraulic cylinder;
A piston that divides the inside of the cylinder tube into first and second chambers;
A rod fixed to the piston and connected to the valve;
A supply passage capable of supplying pressure oil to the first chamber;
A first discharge passage capable of discharging oil from the first chamber;
A stopper chamber defined by the piston in a second chamber when the valve is opened;
A second discharge passage through which oil can be discharged from the second chamber to the tank ,
In the engine valve drive apparatus,
Connecting the first discharge passage to the second chamber;
An engine valve characterized in that a control valve that is closed when the pressure oil is supplied to the first chamber and is open when the oil is discharged from the first chamber is disposed in the first discharge passage. Drive device.   The engine valve drive device according to claim 1, wherein the stopper chamber is connected to the second discharge passage through a throttle. 2. The engine valve drive device according to claim 1, wherein a second discharge passage check valve having a second chamber direction opposite to the second discharge passage is disposed in the second discharge passage.   2. The engine valve drive device according to claim 1, wherein a supply passage check valve having a first chamber direction as a forward direction is disposed in the supply passage.

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