JPH0413413Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a fuel injection pump that can be easily mounted on an engine.

(Prior Art) Some in-line fuel injection pumps installed in diesel engines are designed to variably control the prestroke of the plunger, that is, the stroke required to start injection from the bottom dead center position of the plunger, depending on the load or rotation of the engine. There is something I did.

For example, in Japanese Utility Model Application No. 61-118936, an engagement pin that engages with a control sleeve slidably fitted onto a plunger is attached to a control rod, and the shaft end of the rod is rotated by a rotary solenoid. A fuel injection pump is shown in which the pre-stroke can be changed by being connected to a rotating shaft and swinging an engagement pin through the rotation of the shaft to move the control sleeve up and down.

(Problems to be Solved by the Invention) However, in this conventional injection pump, the rotary solenoid and the rotating shaft linked thereto are attached to the drive side end face of the pump housing.
Since these protruded to the upper side of the end face and occupied the space, when assembling the injection pump to the engine, which is installed with this end face facing the engine, the work space is limited and the assembly area is There was a problem that visibility was obstructed, making work difficult.

The present invention solves these conventional problems by installing an actuator that rotationally drives the control rod and a sensor that detects the rotation angle of the rod at the opposite end of the drive side of the pump housing. By opening the side end faces, it is possible to easily assemble the product into the engine, reduce the installation space on the side opposite to the driving side, and improve the power transmission efficiency of the actuator and the reliability of the sensor output. Moreover, it is an object of the present invention to provide a fuel injection pump that can readily respond to modification of existing equipment.

(Means for Solving the Problems) Therefore, in the fuel injection pump of the present invention, an engagement pin that engages with a control sleeve slidably fitted on the plunger is attached to the control rod, and the engagement pin is attached to the control rod. The pump is equipped with an actuator that rotates and a sensor that detects the rotation angle of the control rod, and the actuator is disposed inside the pump housing at an end opposite to the driving side, and the driving side end face of the pump housing is opened. In the fuel injection pump, an auxiliary rod is connected to the opposite end of the control rod, and a pair of engagement grooves are formed in a diametrical position on the circumferential surface of the auxiliary rod in parallel to the axial direction. The actuator and sensor are arranged on both sides of the rod, and the drive shaft of the actuator and the rotation axis of the sensor are arranged perpendicularly and coaxially with respect to the auxiliary rod, while the drive shaft of the actuator and the rotation axis of the sensor are opposite to each other. Engagement pins are eccentrically protruded from the ends, and these engagement pins are engaged with the pair of engagement grooves, respectively, to facilitate assembly into the engine and to save space on the side opposite to the drive side. The compactness of
It is characterized by improving the power transmission efficiency of the actuator and the reliability of the sensor output, and also by being able to quickly respond to modifications to existing equipment.

(Embodiment) Below, illustrated embodiments in which the present invention is applied to an in-line fuel injection pump will be explained.
In the figure, reference numeral 1 denotes a pump housing, inside which vertical holes 3 corresponding to the number of cylinders of the engine are provided.These holes 3 communicate with an oil reservoir chamber 4, and a hollow cylindrical plunger is inserted into this hole 3. Barrel 5 is fixed.

The inside of the plunger barrel 5 communicates with the oil reservoir chamber 4 through an opening window 6, and a plunger 7 is housed inside this so as to be able to move up and down. Plunger 7
is made vertically movable by engaging a tappet assembly (not shown) attached to its lower end with a cam of a camshaft (not shown) linked to the gearbox 2 of the engine, which is the driving side. An oil guide hole 9 communicating with the oil reservoir chamber 4 and the pressurizing chamber 8 is opened.

The upper circumferential surface of the plunger 7 includes a vertical groove 10 communicating with the oil guide hole 9 and an inclined groove 1 communicating with the groove 10.
1 are formed, and these holes 9 and grooves 10, 11 can be opened and closed by a control sleeve 12. The control sleeve 12 is slidably fitted onto the plunger 7, and has a cut-off hole 13 in its interior that can communicate with the grooves 10 and 11, and has a guide groove 14 and an engagement groove 15 formed on its circumferential surface. has been done.

Of these, the guide groove 14 is formed in the axial direction of the control sleeve 12, and a guide pin 16 fixed to the plunger barrel 5 is engaged in this groove 14 to regulate the rotation of the control sleeve 12. The engagement groove 15 is formed in the middle portion of the control sleeve 12, and the tip of the engagement pin 17 is inserted into the groove 15.

The engagement pin 17 is fixed to the control rod 19 via a set screw 18, and the rod 19
is rotatably supported within the oil reservoir chamber 4 via a bush 20 and a bearing 21, and a hollow auxiliary rod 22 is connected to one end thereof.

Engagement grooves 23 and 24 are formed parallel to each other in the diametrical position on the circumferential surface of the auxiliary rod 22.
An engaging pin, which will be described later, is engaged in 24. That is, on one side of the circumferential surface of the pump housing 1 along the control rod 19, opposite to the drive-side side surface 1a side connected to the gear box 2, that is, on one side of the governor installation side end, there is an actuator housing box 25. is attached, and the box 25
There is an actuator 26 such as a stepping motor inside.
is accommodated.

The operation of the actuator 26 is controlled by a control unit (not shown), and signals from various sensors installed on the engine and fuel injection pump are input to this control unit according to the load or rotational state of the engine. Based on the signal, a built-in microcomputer calculates a target prestroke of the plunger 7, and outputs the calculated value to the actuator 26 as a control signal.

The rotor 27 of the actuator 26 has a drive shaft 2.
One end of the rod 8 is fixed, and the other end is disposed perpendicularly toward the auxiliary rod 22. An engagement pin 2 is provided on the other end surface of the drive shaft 28 at a position eccentric from the shaft center.
9 is provided in a protruding manner, and the pin 29 is engaged in the engagement groove 23 to enable the power of the actuator 26 to be transmitted to the auxiliary rod 22.

On the other hand, on the opposite side of the auxiliary rod 22, a rotation shaft 31 of a sensor 30 such as a potentiometer for detecting the rotation angle of the rod 22 is disposed coaxially with the drive shaft 28, and the end of the shaft 31 An engaging pin 32 protruding eccentrically is engaged in the engaging groove 24. The sensor 30 is installed in a stepped mounting hole 33 formed in the pump housing 1 on the opposite side from the actuator housing box 25, and this is fitted with a synthetic resin sensor housing 34 molded so as to be insertable into the hole 33. It is equipped with

The sensor housing 34 rotatably accommodates the rotation shaft 31, and a terminal 35 to which a constant voltage is applied is provided inside the sensor housing 34.
By touching and moving the wiper 36 provided at the end of the rotating shaft 31 above, a partial pressure V proportional to the position of the wiper 36, that is, the rotation angle of the rotating shaft 31, can be detected at the terminal 35. This detection voltage V can be input to the control unit as a feedback signal.

In addition, 37 in the figure is an oil-tight O-ring attached to the circumferential surface of the sensor housing 34, and 38 is a terminal 35.
This is the lead wire drawn out from the

FIG. 7 shows another embodiment of the present invention, in which the same reference numerals are used for parts corresponding to those of the embodiment described above. In this embodiment, a substantially rectangular flange 39 is provided at the end of the sensor housing 34 exposed on the surface of the pump housing 1, and arc-shaped elongated holes 40, 40 are formed at relative positions of the flange 39. By making the mounting position of the sensor 30 adjustable along the line 40, it is possible to easily match or adjust the prestroke and the corresponding output of the sensor 30. In the figure, 41, 41 are mounting screws.

In the above-described embodiment, the means for transmitting power from the drive shaft 28 to the auxiliary rod 22 and from the auxiliary rod 22 to the rotating shaft 31 is the means for engaging the engaging pins 29, 32 and the engaging grooves 23, 24. Although a bevel gear or a link mechanism may be used in addition to this, it is also possible to use engagement balls in place of the engagement pins 29 and 32.

Furthermore, in the embodiments described above, the actuator 26
and sensors 30 are installed separately on both sides of the circumferential surface of the end portion of the pump housing 1 on the governor installation side.
These may be integrated and installed on one of the peripheral surfaces of the end portions, in short, the driving side end surface 1 of the pump housing 1.
Of course, any installation structure for the actuator 26 and sensor 30 may be adopted as long as it frees up the space around a.

(Function) The fuel injection pump configured in this manner accommodates the actuator 26 on one side of the circumferential surface of the pump housing 1 at the end opposite to the drive side end surface 1a that is linked to the gear box 2 of the engine that is the driving side. Attach the actuator housing box 25,
The sensor 30 is inserted into the stepped hole 33 from the opposite circumferential surface and fixed, and the drive shaft 28 and rotation shaft 3
The engaging pins 29 and 30 protruding from the shaft end of the control rod 19 are engaged in the engaging grooves 23 and 24 of the auxiliary rod 22 connected to the control rod 19, thereby assembling the rod.

Therefore, in this injection pump, by relocating the actuator 26 and sensor 30 from the drive side of the pump housing 1 to the governor installation side, the area around the drive side end face 1a is opened as shown in FIG. This makes it easier to assemble the pump to the engine 2. Unlike the conventional art, where the actuator 26 and sensor 30 occupy the drive side end face of the pump housing 1, the work space is limited and the assembly area is Eliminates the problem of deteriorating the work environment due to obstructed visibility of the surrounding area. In this case, by connecting the auxiliary rod 22 to the end of the control rod 19, the existing control rod 19 can be used, making it easy to modify the existing device.

Further, since the actuator 26 and the sensor 30 are arranged on both sides of the above-mentioned end of the control rod 19, and their drive shaft 28 and rotation shaft 31 are arranged coaxially, the actuator 26 and the sensor 3
Compared to the case where the fuel injection pump 0 is disposed coaxially with the control rod 19, the protrusion toward the governor mounting side is suppressed, and the installation space for the fuel injection pump in this part can be reduced.

Moreover, the drive shaft 28 and the rotation shaft 31 are positioned coaxially and orthogonally to the auxiliary rod 22, and their engagement pins 29, 32 are engaged in the engagement grooves 23, 24. Therefore, the auxiliary rod 22 can be made shorter and the protrusion on the governor mounting side can be suppressed.

In the fuel injection pump assembled to the engine in this manner, the control operation of the control unit is started at the same time as the engine is started, and the prestroke of the plunger 7 is variably controlled in accordance with the load or rotational state of the engine.

In other words, when the load or rotational state of the engine is detected by various sensors installed at appropriate locations on the engine and injection pump, and these signals are input to the control unit, the control unit uses a built-in microcomputer to detect these signals. The target prestroke of the plunger 7 is calculated based on the pre-stroke calculation information of the plunger 7 stored in advance with the input signal as a condition, and the calculated value is outputted to the actuator 26 as a control signal.

The actuator 26 is driven by the control signal and rotates the drive shaft 28 via the rotor 27.
The power is transmitted from an engaging pin 29 protruding from the shaft 28 to an auxiliary rod 22 formed with an engaging groove 23 that engages with the pin 29. The pin 29 is eccentric as shown in the third figure, and when it rotates together with the drive shaft 28, for example in the direction of the upper arrow in the figure, the auxiliary rod 22 is pushed downward through the engagement groove 23. , the control rod 19 to which the rod 22 is connected rotates in the direction of the upper arrow in the figure.

As a result, the engagement pin 17 attached to the control rod 19 swings upward, and the control sleeve 12 that engages with the pin 17 is pushed up through the engagement groove 15, opening the oil guide hole 9. By increasing the stroke of the plunger 7 required for closing, the prestroke is adjusted to increase. Therefore, in this case, the start of injection is delayed.

On the other hand, when the auxiliary rod 22 is pushed around as described above, the power is transmitted to the rotating shaft 31 via the engagement groove 24. As shown in FIG. 5, an engagement pin 32 is eccentrically protruded from the end of the rotation shaft 31.
When the pin 32 is pushed up through the engagement groove 24, the rotation shaft 31 rotates in the direction of the arrow shown in the figure.
For this reason, the wiper 3 fixed to the shaft end of the rotating shaft 31
6 moves together with the shaft 31 and moves in contact with the terminal 35,
The amount of movement is detected between the terminals 35 as a partial pressure value V proportional to the rotation angle of the rotation shaft 31, and the rotation angle of the control rod 19, in other words, the prestroke of the plunger 7 is actually measured.

In this way, in the present invention, the drive shaft 28 and the rotation shaft 3
1 are positioned on the same axis, and are arranged perpendicularly to the auxiliary rod 22, thereby shortening the power transmission path and the displacement transmission path, thereby suppressing their losses and improving their transmission efficiency. sensor 3
The reliability of zero output can be improved.

Moreover, the engagement pins 29 in the engagement grooves 23 and 24,
32 is displaced approximately coaxially with the drive shaft 28 and the rotating shaft 31, it is possible to prevent errors caused by shaft vibration of the auxiliary rod 22.

The above detection signal is then input as a feedback signal to the control unit, which compares the target prestroke and the actual prestroke, and outputs a control signal corresponding to the error to the actuator 26, so that the current prestroke can be adjusted to the target. Corrected in prestroke.

(Effects of the Invention) As described above, the fuel injection pump of the present invention has the effect of easily adapting to modification of existing equipment because the auxiliary rod is connected to the opposite end of the control rod.

In addition, the present invention forms a pair of engagement grooves parallel to the axial direction on the circumferential surface of the auxiliary rod, arranges the actuator and sensor on both sides of the auxiliary rod, and rotates the drive shaft of the actuator and the sensor. Since the moving shaft is disposed perpendicularly and coaxially with the auxiliary rod, the power transmission path by the actuator and the rotational displacement transmission path of the auxiliary rod can be shortened, suppressing their losses and improving the transmission. It is possible to improve efficiency and reliability of sensor output.

Furthermore, compared to the case where the actuator and sensor are disposed coaxially with the control rod, protrusion toward the governor protruding side is suppressed, and the installation space for the fuel injection pump in the relevant portion can be reduced.

Moreover, in the present invention, engagement pins are eccentrically protruded from opposite ends of the drive shaft of the actuator and the rotating shaft of the sensor, which are arranged coaxially, and these engagement pins are respectively engaged with a pair of engagement grooves. Since they are combined, the auxiliary rod can be made shorter and the space can be made more compact.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a sectional view of the main part along line A-A' in Figure 1,
The figure is an exploded perspective view of the main parts of the present invention, Fig. 4 is an enlarged sectional view of the main parts of Fig. 1, and Fig. 5 is an explanatory diagram showing the relationship between the auxiliary rod and the rotation axis. FIG. 6 is a sectional view taken along line B-B' in FIG. 1, and FIG. 7 is an external view showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Pump housing, 1a... Drive side end surface, 7... Plunger, 12... Control sleeve,
17... Engagement pin, 19... Control rod, 26... Actuator, 30... Sensor.

Claims (1)

[Scope of utility model registration request] an actuator for rotationally driving the control rod by mounting an engagement pin on the control rod that engages with a control sleeper slidably fitted on the plunger;
A fuel injection pump comprising a sensor for detecting the rotation angle of the control rod, the actuator being disposed inside the pump housing at an end opposite to the driving side, and the driving side end face of the pump housing being open. An auxiliary rod is connected to the opposite end of the control rod, and a pair of engagement grooves are formed parallel to the axial direction on the circumferential surface of the auxiliary rod, and an actuator and a sensor are mounted on both sides of the auxiliary rod. The drive shaft of the actuator and the rotation axis of the sensor are arranged perpendicularly and coaxially with respect to the auxiliary rod, while an engaging pin is installed at opposite ends of the drive shaft of the actuator and the rotation axis of the sensor. A fuel injection pump characterized in that the engaging pins are provided eccentrically and projectingly, and these engaging pins are respectively engaged with the pair of engaging grooves.