JP2580795Y2 - Hydraulic governor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic governor for controlling a fuel injection amount of a diesel engine according to an engine speed.

[0002]

2. Description of the Related Art A conventional hydraulic governor 101 shown in FIG.
A housing 102, a power piston 103 built in the housing 102 and connected to a fuel injection device (not shown), and a control valve built in the housing 102 and interposed between the power piston 103 and the hydraulic pump 104 105, a compensating piston 108 built in the housing 102 and connected to the power piston 103 via compression springs 106 and 107, and a pair of oils partitioned by the compensating piston 108 and communicated with the tank 109. Chambers 110 and 111 and one of the oil chambers 11
0 and a variable throttle valve 112 interposed between the tank 109.

The spool 105a of the control valve 105 is interlocked with the flyweight 113, and is displaced upward in the figure when the engine speed is increased.
Due to the displacement of 5a, high-pressure oil is supplied from the pump 104 to the oil chamber 114 above the power piston 103, and the power piston 103 is displaced downward in the drawing, and the displacement of the power piston 103 reduces the fuel injection amount. When the engine speed decreases, the spool 105a is displaced downward in the figure, and the movement of the spool 105a also supplies high-pressure oil to the oil chamber 115 below the power piston 103, and the power piston 103 moves upward in the figure. The displacement of the power piston 103 increases the fuel injection amount.

[0004] The displacement of the power piston 103 in the fuel decreasing direction causes the compensating piston 1 to move.
08 increases the volume of one oil chamber 110 partitioned by the oil chamber 110. Due to the increase in the volume of the oil chamber 110, one oil chamber 110
The hydraulic pressure between and the variable throttle valve 112 becomes a negative pressure. When this negative pressure acts on the spool 105a of the control valve 105, the displacement of the spool 105a in the downward direction in the drawing, that is, in the fuel increasing direction is promoted. Further, the displacement of the power piston 103 in the fuel increasing direction causes the one oil chamber 1 to move.
The volume of 10 is reduced. Due to the decrease in the volume of the oil chamber 110, the oil pressure between the one oil chamber 110 and the variable throttle valve 112 becomes positive. When the positive pressure acts on the spool 105a of the control valve 105, the displacement of the spool 105a in the upper direction in the drawing, that is, in the fuel decreasing direction is promoted.
With this compensator function, the response speed of the change in the fuel injection amount to the change in the engine speed is increased, and hunting is prevented. Further, by adjusting the opening degree of the variable throttle valve 112, the settling time of the engine speed is adjusted.

[0005]

In order to prevent hunting of the engine, it is preferable to reduce the opening of the variable throttle valve 112. However, if the opening becomes excessively small, the engine is rapidly decelerated from a high speed range to a low speed range. When this is done, there is a problem that the settling time becomes longer and the engine stalls. That is, when the engine is suddenly decelerated, it takes time to decelerate because the difference in the number of revolutions is large. Then, the hydraulic pressure between one of the oil chambers 110 partitioned by the compensating piston 108 and the variable throttle valve 112 becomes a negative pressure at the beginning of deceleration as described above. Oil flows in from 109 and becomes positive pressure. Then, the positive pressure prevents the compensating piston 108 from displacing upward in the drawing, and prevents the power piston 103 interlocking with the compensating piston 108 from displacing in the fuel increasing direction. It takes a long time to set the rotation speed,
An engine stall is likely to occur.

An object of the present invention is to provide a hydraulic governor capable of solving the above-mentioned problems of the prior art.

[0007]

The first aspect of the present invention is characterized by a housing, a power piston built in the housing and connected to a fuel injection device,
A control valve built into the housing and interposed between the power piston and the hydraulic pump, a compensating piston built into the housing and interlocking with the power piston, and separated by the compensating piston into the tank A pair of communicating oil chambers, and a variable throttle valve interposed between one of the oil chambers and the tank, the power piston is operated by the displacement of the control valve according to the engine speed, and the fuel injection amount is adjusted. The displacement of the power piston in the fuel decreasing direction increases the volume of the one oil chamber,
In the hydraulic governor in which the hydraulic pressure between one oil chamber and the variable throttle valve acts on the control valve, a communication path communicating the one oil chamber side and the other oil chamber side is provided, and the communication path is It is opened and closed by the compensating piston, and is opened when the power piston is displaced by a certain amount or more in the fuel decreasing direction from the idle position.

[0008] The compensating piston is
Are interlocked via the compression spring to the power piston, the other the regulating member of the pair of oil chambers are built, the regulating member, before
The compensating piston opens the communication passage
When sea urchin said power piston being displaced beyond a predetermined distance in the fuel decreasing direction than the idle position, it is preferably to regulate the displacement of the fuel decreasing direction of the Compensating piston
No. In this case, it is preferable that the regulating member is constituted by a cam, and the cam is rotatable from the outside of the housing, and the regulation of the displacement of the power piston in the fuel decreasing direction is preferably adjusted by the rotation of the cam.

[0009]

According to the structure of the first aspect of the present invention, when the power piston is displaced by more than a predetermined amount in the fuel decreasing direction from the idle position, the communication passage between the pair of oil chambers partitioned by the compensating piston is opened. By opening the communication passage, the pressure between one oil chamber and the variable throttle valve communicates with the tank via the other oil chamber side, so that the pressure does not become positive, and the compensating piston moves in the fuel increasing direction. The generation of pressure for preventing displacement can be prevented. As a result, it is possible to prevent the displacement of the power piston linked to the compensating piston in the fuel increasing direction at the time of rapid deceleration of the engine, thereby preventing a prolonged settling time of the engine speed and an engine stall. Further, when the position of the power piston is on the fuel increasing side from the idle position where the engine speed becomes the idling speed, the communication passage is closed by the compensating piston, so that the compensator function is not impaired.

With the provision of the regulating member, when the power piston is displaced by a certain amount or more in the fuel decreasing direction from the idle position, the compensating piston comes into contact with the regulating member and the displacement of the power piston in the fuel decreasing direction is prevented. You. Further, the compression spring interposed between the compensating piston and the power piston is elastically deformed by restricting the displacement of the compensating piston by the restricting member, so that the elastic force acts on the power piston. This makes it possible to quickly return the power piston linked to the compensating piston in the fuel increasing direction, thereby preventing a prolonged settling time and a stall during sudden deceleration of the engine. In addition, when the position of the power piston is on the fuel increase side from the idle position where the engine speed is the idling speed, the displacement of the compensating piston in the fuel decreasing direction is not prevented, so that the compensator function is not provided. It will not be compromised. By configuring the regulating member with a cam,
The regulation amount of the displacement of the compensating piston in the fuel decreasing direction can be adjusted to an optimum value.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

[0012] Hydraulic governor 1 shown in FIG. 1 comprises a housing 2, the power piston 3 is built in the housing 2
To have. The power piston 3 has an output lever 3b swingably attached to the housing 2 about the output shaft 3c.
Via a link mechanism 3a, and its output lever 3b
Is connected to a control rack (not shown) of a fuel injection device such as a fuel injection pump or a unit injector. A pair of oil chambers 15 and 16 partitioned by the power piston 3 are formed in the housing 2. The pressure receiving area of the power piston 3 is the oil chamber 1 on the upper side in the figure.
Write in 5 is smaller than in the oil chamber 16 on the lower side
Have been.

The housing 2 has a hydraulic pump 1
0 is built in. The pump 10 is a gear pump having a driving gear 11 and a driven gear 12 that mesh with each other, and the driving gear 11 is driven by an engine,
The driven gear 12 is integrated with a sleeve 13 rotatably inserted into the housing. A fly weight 18 is attached to the upper end of the sleeve 13, and the fly weight 18 is connected to the spool 14. The control valve 19 is formed by the spool 14 and the sleeve 13.
Is configured. When the sleeve 13 is rotated by the rotation of the engine and the flyweight 18 is displaced by centrifugal force, the spool 14 is displaced vertically in the drawing according to the amount of displacement. Pressure oil is supplied from the pump 10 to the power piston 3 via the control valve 13.

The housing 2 has a compensating piston 4 built therein. A connecting rod 30 is integrated with the compensating piston 4, the rod 30 is inserted into the power piston 3, and a compression spring 31 sandwiched between a flange 30 a provided on the outer periphery of the rod 30 and the power piston 4. 32 are provided. A pair of oil chambers 5 and 6 partitioned by the compensating piston 4 and communicated with the tank 7
Are formed in the housing 2. One oil chamber 5
A needle valve (variable throttle valve) 8 is interposed between the fuel cell and the tank 7.

The space between one oil chamber 5 and the needle valve 8 partitioned by the compensating piston 4 communicates with the insertion hole 13 ′ of the sleeve 13 of the control valve 19. As a result, the hydraulic pressure between one of the oil chambers 5 and the needle valve 8 is reduced by the spool 1 of the control valve 19.
Acts on 4.

The spool 1 of the control valve 19
4 is displaced upward in the figure when the engine speed increases, and the displacement of the spool 14 connects an oil passage 16a that connects the control valve 19 and the oil chamber 16 below the power piston 3 to the tank 7, and High pressure oil is supplied from the pump 10 to the oil chamber 15 above the piston 3 only in the oil passage 15a.
Is supplied via As a result, the power piston 3 is displaced downward in the drawing, and the displacement of the power piston 3 decreases the fuel injection amount and the engine speed. When the engine speed decreases, the spool 14 is displaced downward in the figure. Due to the displacement of the spool 14, an oil passage 16a connecting the control valve 19 and the oil chamber 16 below the power piston 3 is connected to the pump 10. Then, high-pressure oil is also supplied from the pump 10 to the oil chamber 16 below the power piston 3. As a result, the power piston 3 is displaced upward in the drawing, and the displacement of the power piston 3 increases the fuel injection amount and the engine speed.

The displacement of the power piston 3 in the fuel decreasing direction, that is, the downward direction in the figure, increases the volume of one oil chamber 5 partitioned by the compensating piston 4. Due to the increase in the volume of the oil chamber 5, the oil pressure between the one oil chamber 5 and the needle valve 8 becomes negative. When the negative pressure acts on the spool 14 of the control valve 19, the displacement of the spool 14 in the downward direction in the drawing, that is, in the fuel increasing direction is promoted. Further, the displacement of the power piston 3 in the fuel increasing direction, that is, the upward movement in the drawing, reduces the volume of one oil chamber 5 partitioned by the compensating piston 4. Due to the decrease in the volume of the oil chamber 5, the oil pressure between the one oil chamber 5 and the needle valve 8 becomes positive. When the positive pressure acts on the spool 14 of the control valve 19, the displacement of the spool 14 upward in the drawing, that is, in the fuel decreasing direction is promoted. With this compensator function, the response speed of the change in the fuel injection amount to the change in the engine speed is increased, and hunting is prevented. In addition, the needle valve 8
By adjusting the opening degree, the settling time of the engine speed is adjusted.

A control lever 25 is swingably attached to the housing 2, and a compression spring 27 is connected to the control lever 25 via a link mechanism 26. The spring 27 serves as a spool 14 of the control valve 19. An elastic force that pushes in the middle and downward directions, that is, in the fuel increasing direction is applied. The elastic force changes by operating the control lever 25. Thus, when the control lever 25 is operated, the spool 14 is displaced and the engine speed changes.

Then, the compensating piston 4
A communication passage 40 is provided for communicating one oil chamber 5 and the other oil chamber 6 which are partitioned by each other. This communication passage 40 is closed by the compensating piston 4 in the state shown in FIG. From this state, when the power piston 3 is displaced more than a certain amount in the fuel decreasing direction from the idle position,
When the compensating piston 4 interlocking with the power piston 3 is displaced downward, the communication passage 40 is opened, and both oil chambers 5,
6 communicates.

Thus, when the power piston 3 is displaced in the fuel decreasing direction from the idle position and the communication passage 40 is opened at the time of rapid deceleration of the engine, the space between the one oil chamber 5 and the needle valve 8 becomes the other oil chamber. Since it communicates with the tank 7 via the 6 side, the pressure does not become positive. That is, it is possible to prevent generation of a pressure that prevents the displacement of the compensating piston 4 in the fuel increasing direction. As a result, it is possible to prevent a prolonged settling time of the engine rotational speed and a stall during sudden deceleration of the engine. Further, when the position of the power piston 3 is on the fuel increasing side from the idle position where the engine speed becomes the idling speed, the communication passage 40 is closed, so that the compensator function is not impaired and the engine hunting is effectively performed. Can be prevented.

A shim 45 (a regulating member) is incorporated in the other oil chamber 6 partitioned by the compensating piston 4. When the power piston 3 is displaced by a certain amount or more in the fuel decreasing direction from the idle position, the shim 45 abuts on the rod 30 of the compensating piston 4 and prevents the displacement of the compensating piston 4 in the fuel decreasing direction. . Also, one compression spring 31 interposed between the compensating piston 4 and the power piston 3 is elastically deformed by the displacement of the compensating piston 4 being regulated by the shim 45. Acts on piston 3. As a result, the power piston 3 linked to the compensating piston 4 can quickly return to the fuel increasing direction, so that the settling time and the engine stall at the time of rapid deceleration of the engine can be prevented. When the position of the power piston 3 is on the fuel increase side from the idle position where the engine speed is the idling speed, the shim 45 does not prevent the displacement of the compensating piston 4 in the fuel decreasing direction. Since there is no compensator function, the hunting of the engine can be effectively prevented without impairing the compensator function. The position at which the displacement of the compensating piston 4 is restricted by the shim 45 in the fuel decreasing direction is lower than the position at which the compensating piston 4 opens the communication passage 40, that is, on the fuel decreasing direction side. In a state where the displacement of the saving piston 4 in the fuel decreasing direction is restricted by the shim 45, the communication path 40 is open.

FIGS. 2A and 2B show a different embodiment. The difference from the above embodiment is that the cam 4 is replaced with the shim 45. FIG.
5 'restricts the displacement of the compensating piston 4 in the fuel decreasing direction. That is, the cam 4
5 'is inserted into the housing 2 so as to be rotatable around a support shaft 46, and the end of the support shaft 46 projects outside the housing 2, and a plate 47 is fixed to the protruding end. An elongated hole 48 located on a concentric circle of the support shaft 46 is formed in the plate 47.
The plate 47 is fixed to the housing 2 by screws 49 inserted into the long holes 48. Thus, when the screw 49 is loosened and the plate 47 is rotated, the cam 45 ′ rotates around the support shaft 46. This cam 45 '
By controlling the rotation of, the regulating amount of the displacement of the compensating piston 4 in the fuel decreasing direction can be adjusted to the optimal value.

[0023]

According to the hydraulic governor of the present invention, it is possible to prevent a prolonged settling time and a stall during sudden deceleration of the engine without impairing the compensator function for preventing hunting of the engine.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a hydraulic governor according to an embodiment of the present invention.

FIG. 2 is a partial sectional view and a partial side view of a hydraulic governor according to another embodiment of the present invention.

FIG. 3 is a diagram illustrating the configuration of a conventional hydraulic governor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic governor 2 Housing 3 Power piston 4 Compensating piston 5 One oil chamber 6 The other oil chamber 8 Variable throttle valve 40 Communication path 45 Regulator 45 'Cam

Claims (3)

(57) [Scope of request for utility model registration] 1. A housing, a power piston built in the housing and connected to the fuel injection device, a control valve built in the housing and interposed between the power piston and the hydraulic pump, A compensating piston built in and interlocked with the power piston, a pair of oil chambers partitioned by the compensating piston and communicating with the tank, and a variable throttle valve interposed between one of the oil chambers and the tank; The power piston is operated by the displacement of the control valve according to the engine speed, the fuel injection amount is adjusted, the displacement of the power piston in the fuel decreasing direction increases the volume of the one oil chamber, The hydraulic pressure between one oil chamber and the variable throttle valve acts on the control valve. In the hydraulic governor, a communication path communicating the one oil chamber side and the other oil chamber side is provided,
The hydraulic governor is characterized in that the communication passage is opened and closed by the compensating piston, and is opened when the power piston is displaced by a predetermined amount or more in a fuel decreasing direction from an idle position. 2. The compensating piston has a front end.
The power piston is interlocked via a compression spring, and a regulating member is incorporated in the other of the pair of oil chambers .
The compensating piston opens the communication passage
2. The hydraulic governor according to claim 1 , wherein the displacement of the compensating piston in the fuel decreasing direction is restricted when the power piston is displaced in the fuel decreasing direction more than the idle position. 3. A regulating member comprising a cam, the cam being rotatable from the outside of the housing, and the regulating amount of the displacement of the power piston in the fuel decreasing direction is adjusted by the rotation of the cam. The hydraulic governor according to claim 2, wherein