JPH0444821Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an injection amount control device for a fuel injection pump for a diesel engine.

Prior Art As shown in Fig. 1, the sleeve 4 is reciprocated by the mounting load of the main spring 2 whose mounting load is set by the control lever 1 and the centrifugal force of the flyweight 3 rotated by the engine. An injection amount control device is known in which the sleeve 4 is connected to a hydraulic tracing mechanism 6 via a link 5, and the hydraulic tracing mechanism 6 causes a control rack 7 of a fuel injection pump to reciprocate.

In this injection amount control device, the sleeve 4 stops when the mounting load of the main spring 2 and the centrifugal force of the flyweight 3 are balanced, and the position of the control rack 7 is determined to match the position of the sleeve 4. When the engine rotation speed changes due to the influence of load or the position of control lever 1 changes, the centrifugal force of flyweight 3 and the mounting load of main spring 2 are balanced. The alignment is broken and the sleeve 4 moves to a position where it is even.

This movement of the sleeve 4 causes the link 5 to swing, moving the input side of the hydraulic tracing mechanism 6, and moving the output side by the same stroke in the direction in which the input side moved, moving the control rack 7 and adjusting the injection amount. It operates to increase or decrease.

According to this injection amount control device, since the control rack 7 is pushed by the hydraulic tracing mechanism 6, it is possible to reliably push the control rack 7 even when the engine speed is low and the force pushing the sleeve 4 by the flyweight 3 is small. can.

However, when this hydraulic tracing mechanism 6 is used, its responsiveness is poor, so that the control rack 7 does not move immediately in response to changes in engine speed, but moves with a time delay, which is undesirable.

Purpose of the invention: The control rack can be reliably moved from low engine speeds to locked-down engine speeds, and
To enable a control rack to be moved immediately without delay in response even when the engine rotation speed is high.

Structure of the invention The hydraulic tracing mechanism is composed of a power piston and a valve, and the valve is provided with a stopper that comes into contact with the power piston when the valve moves a predetermined stroke in the direction of increasing the injection amount.

Embodiment FIG. 2 is a sectional view of a hydraulic tracing mechanism, in which the hydraulic tracing mechanism 6 has a power piston 1 attached to a valve body 13.
4 are fitted and inserted to form the first and second pressure receiving chambers 15 and 16, and a valve 17 is fitted and inserted into the power piston 14 to disconnect the first and second pressure receiving chambers 15 and 16 from the drain port 18. At the same time, the inlet port 19 is opened and communicated with the first pressure receiving chamber 15, and the power piston 14 is opened and communicated with the first pressure receiving chamber 15.
is connected to the control rack 7,
In the illustrated state, the first and second large diameter portions 1 of the valve 17
7a and 17b block off the first pressure receiving chamber 15 and the second pressure receiving chamber 16 and the drain port 18 to hold the power piston 14 in the illustrated position, and move the valve 17 to the right from the illustrated state. Then, the second pressure receiving chamber 16 and the drain port 18 communicate with each other, and the power piston 14 moves to the right due to the pressure in the first pressure receiving chamber 15. When the power piston 14 moves by the amount of movement of the valve 17, the second pressure receiving chamber 16 and the drain port 18 communicate with each other. 18 is cut off and the power piston 14 stops, and when the valve 17 is moved to the left from the illustrated state, the first and second pressure receiving chambers 15 and 16 are communicated with each other, and the drain port 18 is cut off, and the first and second The power piston 14 moves to the left due to the pressure receiving area difference between the two pressure receiving chambers 15 and 16, and when it moves the same amount as the valve 17, the first
The pressure receiving chamber 15 and the second pressure receiving chamber 16 are cut off, the drain port 18 and the second pressure receiving chamber 16 are cut off, and the power piston 14 is stopped.

That is, as the valve 17, which is the input side, moves, the power piston 14, which is the output side, moves in the same direction and by the same distance.

A valve 17 is connected to the sleeve 4 via a link 5.

A stopper pin 20 is fitted and fixed to the valve 17, and this stopper pin 20 faces slidably into the notched groove 21 of the power piston 14, and the stopper pin 20 is fitted and fixed to the valve 17.
7 is pushed leftward to some extent by the sleeve 4 via the link 5, the stopper pin 20 comes into contact with one end surface 21a of the notched groove 21, and the valve 17 and the power piston 14 move as one. It is set as.

Because of this, the valve 17 is connected to the sleeve 4, and the stopper pin 20 is connected to the one end surface of the notched groove.
When the control rack 7 is moved to a range where it does not come into contact with the sleeve 1a, that is, when the engine speed is low and the force of pushing the sleeve 4 by the flyweight 3 is weak, the control rack 7 is moved by the hydraulic pressure of the hydraulic tracing mechanism 6. , the control rack 7 can be moved reliably in a low speed range.

Further, when the engine rotational speed reaches a high speed range and the stopper pin 20 comes into contact with the one end surface 21a of the notch groove, the movement of the sleeve 4 is caused by the link 5, the valve 17,
It acts directly on the power piston 14 via the stopper pin 20, and the control rack 7 can be moved immediately without response delay.

At this time, the moving force of the sleeve 4 and the centrifugal force of the flyweight 3 increase, so that the control rack 7 can be moved reliably by these forces.

Effect of the invention In the low speed range, the stroke of the valve 17 toward the first position due to the centrifugal force of the flyweight 3 is short and the stopper does not come into contact with the power piston 14, so the control rack 7 is moved by the hydraulic pressure of the hydraulic tracing mechanism 6. Even if the centrifugal force of the flyweight 3 is small, the control rack 7 can be moved reliably, and in the high-speed range, the stroke of the valve 17 toward the first position due to the centrifugal force of the flyweight 3 is long, and the stopper hits the power piston 14. Because they touch each other, the centrifugal force causes control rack 7
Since the control rack 7 is directly moved, the control rack 7 can be reliably moved from a low speed to a high speed range, and at the same time, the control rack 7 can be moved quickly without response delay in a high speed range.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional example, and FIG. 2 is a sectional view showing an embodiment of the hydraulic tracing mechanism of the present invention. 1 is the control lever, 2 is the main spring,
3 is a fly weight, 4 is a sleeve, 5 is a link, 6 is a hydraulic tracing mechanism, 7 is a control rack, 14 is a power piston, and 17 is a valve.

Claims (1)

[Scope of utility model registration request] The sleeper 4 is moved by the mounting load of the main spring 2 whose mounting load is set by the control lever 1 and the centrifugal force of the flyweight 3, and the sleeper 4 operates the hydraulic tracing mechanism 6 to move the control rack 7. In the injection amount control device, the oil pressure tracing mechanism 6 is connected to the control rack 7 and the pressure in the first pressure receiving chamber 15 communicating with the hydraulic source is used to move the injection amount in the direction of increasing or decreasing the injection amount. a power piston 14 that moves in the direction of increasing the injection amount by the pressure of the second pressure receiving chamber 16;
A first position where the first pressure receiving chamber 15 and the second pressure receiving chamber 16 are communicated along the power piston 14 and a first position where the first pressure receiving chamber 15 and the second pressure receiving chamber 16 are disconnected and the second pressure receiving chamber 16 is in communication with each other.
and a valve 17 that moves to a second position communicating with the drain, and when the sleeve 4 is moved by the centrifugal force of the flyweight 3 by a link 5, the valve 17 and the sleeve 4 are moved to the first position. When the sleeve 4 moves under the mounting load of the main spring 2, the valve 17 is connected to move toward the second position, and the valve 17 is connected to the valve 17 so that the valve 17 moves toward the first position. An injection amount control device for a fuel injection pump, characterized in that a stopper is provided that comes into contact with the power piston 14 when the piston moves a predetermined stroke.