JPH028141B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection pump for a diesel engine, and in particular to a fuel injection pump for a diesel engine, in which a plurality of plunger pumps are arranged radially around one rotating shaft to simplify and compact the structure. Regarding injection pumps.

Conventionally, in-line fuel injection pumps used in diesel engines have pump units arranged in a straight line for the number of cylinders in the engine, and in-line pumps require separate ties and governors. For this reason, the structure is complicated and large, and the weight is also large, resulting in high cost. Furthermore, in the recently used distribution type fuel injection pump, the fuel pumped from one pump unit is distributed to each cylinder by a distributor.
The drawback was that a large amount of fuel could not be injected.

In addition, in the fuel injection pump disclosed in Japanese Utility Model Publication No. 15-9548, a single rotating swash plate reciprocates the same number of plungers having the same metering function through a plurality of thrust rods, thereby producing the same number of plunger pumps. The fuel injection amount of the plunger pump is adjusted by rotating the same number of small gears as described above by a single master gear that can be driven and rotated relative to the rotating swash plate. In the conventional example, since the fuel injection pump itself was not equipped with a structure for controlling the fuel injection timing, there was an inconvenience that a timer, which is commonly used in the past, had to be separately installed.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art, and its purpose is to provide a plurality of plungers having a fuel metering function around one rotating shaft. By radially arranging the plunger pumps,
Eliminates the need for a separate fuel metering valve device,
An object of the present invention is to provide a small and lightweight fuel injection pump. Another purpose is to enable fuel injection with a simple structure by pressing the plungers attached to each of a plurality of plunger pumps with the cam surface of a single cam body in the order of injection. . Another purpose is to install a tappet that engages with the cam surface of the cam body and presses the plunger so that it can rotate relative to a plurality of plunger pumps, and adjusts the injection timing by detecting at least the rotational speed of the engine. To enable adjustment of fuel injection timing with a simple structure by rotating a timing control sleeve connected to a detector. Still another object is to make it possible to adjust the fuel injection amount with a simple structure by using a single control gear to rotate a control pinion that integrally rotates the plungers attached to each of a plurality of plunger pumps. It is to do so.

In short, the present invention includes a short cylindrical frame, a cam drive shaft that is supported by the axial center of the frame with limited axial movement and rotates in conjunction with the rotation of the engine, and the cam drive shaft. A plunger having a fuel metering function, which includes a sleeve arranged radially around the frame and fixed to the frame, and a control pinion that is slidably inserted into the shaft center of the sleeve and integrally attached thereto. a plurality of plunger pumps, each having a plurality of plunger pumps; a cam body fixed to the cam drive shaft; a timing control sleeve connected to a detector that detects engine rotational speed and adjusts injection timing; and a cam surface of each plunger of the plunger pump and the cam body that is slidably fitted into the timing control sleeve. a plurality of tappets arranged so as to be able to face each other, and a control gear that is rotatably fitted into the cam drive shaft, meshes with the plurality of control pinions, and rotates in conjunction with the operation of the fuel injection amount adjustment device. It is characterized by having the following.

The present invention will be explained below based on embodiments shown in the drawings. The fuel injection pump 1 according to the present invention includes a frame 2
, cam drive shaft 3, and plunger pump 4
, a cam body 5, a timing control sleeve 6, a tappet 7, and a control gear 8. The frame body 2 is fixed to the engine body 11 and is formed into a short cylindrical shape.

The cam drive shaft 3 is rotatably supported at the axial center of the frame body 2 by a bearing 12 having a structure capable of withstanding thrust loads, and is rotatably supported by an engine (not shown). It is designed to rotate in conjunction with rotation.

A plurality of plunger pumps 4 are arranged radially around the frame body 2 around the cam drive shaft 3, and in this embodiment, four plunger pumps are arranged.
The plunger pump is fitted with a sleeve 13 that is fitted into a hole 2a formed on the outer peripheral surface of the frame body 2, and a hollow hole 13a formed in the axial center of the sleeve. The plunger 14 is fitted into the plunger 14 and has a fuel metering function, and a control pinion 15 is provided. A cutout groove 14a is obliquely formed on the outer peripheral surface of the plunger 14. Also, the shaft portion 14b of the plunger
Two grooves 14c are formed facing each other in the axial direction.
, the collar 15a of the control pinion 15
is fitted therein, and the control pinion rotates integrally with the plunger 14. In Fig. 2, 18 is a fuel intake/discharge port, 19
is the injection pipe.

Then, the plunger 14 moves in the direction of arrow A in FIG. When the cutout groove 14a meets the fuel intake/discharge port 18, the fuel flows back into a fuel reservoir (not shown), and the pumping of the fuel ends.

The cam body 5 is formed into a disk shape and is fixed to the cam drive shaft 3. The timing control sleeve 6 is rotatably fitted into the cam drive shaft 3, and a collar portion 6a formed on the timing control sleeve is disposed between the plunger 14 and the cam body 5. Further, a timing control lever 21 is fixed to the timing control sleeve, and the timing control lever is connected to a forked portion 23 of an actuator 23 of a detector 22 fixed to the frame body 2.
The timing control sleeve 6 is connected to the detector 22 by being fitted into the portion a. When the detector 22 detects the engine speed, load, temperature, etc. and operates, the actuator 23 moves, and the timing control sleeve 6 can rotate by a certain angle via the timing control lever 21. The tappets 7 are arranged so as to be able to face the plungers 14 of the plunger pump 4, respectively, and the collar portion 6 of the timing control sleeve 8.
The tappet is slidably inserted into four holes 6b formed in the tappet, and rollers 25, 2 are provided at both ends of the tappet.
6 is pivotally mounted. The roller 25 is set so as to come into contact with the cam surface 5a of the cam body 5, and the roller 26 is set so as to come into contact with four spring receivers 27 arranged between the roller and the plunger 14. The spring receiver is compressed by a compression spring 28.
As shown in FIG. 2, they are opposed in the direction of arrow B, so that the lower end of the plunger 14 can come into contact with them.

The control gear 8 is fitted into the cam drive shaft 3 and is adapted to mesh with control pinions 15 respectively attached to the four plungers 14. And the control gear is
A fuel injection amount adjusting device, for example in a car, is connected to a governor 29 that operates in conjunction with the operation of an accelerator pedal, etc., and the governor detects the engine speed and rotates the control gear 8. ing.

The present invention is configured as described above, and its operation will be explained below. When the cam drive shaft 3 rotates in conjunction with the rotation of the engine and the cam body 5 rotates, the cam surface 5a of the cam body causes the tappet 7 and the spring receiver 27 to
Plunger pump 4 arranged in injection order via
The plunger 14 is sequentially pressed in the direction of arrow A, as shown in FIG. 2, against the spring pressure of the compression spring 28. The compressed high-pressure fuel then passes through the injection pipe 19 from the injection nozzle (not shown) to the combustion chamber of the engine (not shown).
is injected into.

As described above, the four plunger pumps 4 arranged radially around the cam drive shaft 3 on the frame body 2 inject high-pressure fuel in the injection order for each revolution of the cam body 5, and are injected into a single pump. Since a plurality of plunger pumps 4 can be operated by the cam body 5, the fuel injection pump 1 has a simple structure and is small and lightweight.

In this case, the load applied to the cam surface 5a of the cam body 5 will be quite large, but if a material with high wear resistance, such as a cemented carbide chip, is used, the durability will be sufficiently increased. Further, the number of plunger pumps 4 is not limited to four, and more can be attached to the frame 2, and the tappet 7 can be adjusted accordingly.
All you have to do is set it up. Further, although rollers 25 and 26 are pivotally attached to both ends of the tapepet, one roller 26 may be separated and attached to the spring receiver 27.

In Fig. 2, for example, if the rotation direction of the cam drive shaft 3 is clockwise when viewed from the right side (counterclockwise in Fig. 1), the engine speed will increase and the injection timing of the plunger pump 4 should be made earlier. In this case, the detector 22 detects the rotational speed of the engine and operates the actuator 23, and the timing control sleeve 6 rotates in the direction of arrow D via the timing control lever 21. As a result, the engagement between the cam surface 5a of the cam body 5 and the roller 25 of the tappet 7 is made earlier, and the injection timing of the plunger pump 4 can be made earlier. Conversely, when the engine speed becomes low and it is desired to delay the injection timing of the plunger pump 4, the timing control sleeve 6 rotates in the direction of arrow E. In the embodiment, the injection timing is adjusted according to the engine rotation speed, but the combination of a microcomputer and an actuator allows the timing control lever 21 to be controlled based on engine load, engine cooling water temperature, oil oil temperature, engine load, engine rotation speed, etc. It is also possible to select the optimal injection timing for the operating condition of the engine by controlling the temperature and other factors.

In this way, plunger 1 of plunger pump 4
4 and the cam surface 5a of the cam body 5, the timing control sleeve 6 is slidably fitted with four tappets 7 arranged so as to be able to face each other, respectively, and is rotated according to the engine speed, etc. Therefore, since the injection timing of the fuel injection pump 1 can be adjusted, there is no need for a conventional large-sized timer with a complicated structure.

Next, the adjustment of the fuel injection amount will be explained. For example, when the accelerator pedal is operated, the governor 29 is activated, the governor detects the engine speed, and the control gear 8 is rotated appropriately. Then, the four control pinions 15 rotate appropriately at the same time, the plunger 14 rotates, and the position of the notch groove 14a of the plunger 14 relative to the fuel intake/discharge port 18 moves, thereby adjusting the fuel injection amount. can. In this way, the fuel injection amount can be adjusted by rotating the control gear 8 and rotating the plunger 14 via the control pinion 15. There is no need for a control rack that slides around and requires a considerable amount of space, and the entire device is shaped like a thin disk and is more compact.

Since the present invention is constructed and operates as described above, a plurality of plunger pumps each having a plunger having a fuel metering function are arranged radially around one rotating shaft. Therefore, it is possible to eliminate the need to separately provide a fuel metering valve device and to obtain a small and lightweight fuel injection pump. Furthermore, since the plungers attached to each of the plurality of plunger pumps can be pressed in the order of injection by the cam surface of a single cam body, there is an advantage that fuel can be injected with a simple structure. It is also equipped with a tappet that engages with the cam surface of the cam body and presses the plunger, so that it can rotate relative to multiple plunger pumps, and is connected to a detector that detects at least the engine rotation speed and adjusts the injection timing. By rotating the timing control sleeve, it is possible to easily adjust the fuel injection timing. In addition, since the control pinions integrally attached to the plungers attached to each of multiple plunger pumps can be simultaneously rotated by one control gear, the fuel injection amount can be adjusted with a simple structure. Much better results can be obtained compared to fuel injection pumps.

[Brief explanation of drawings]

The drawings relate to embodiments of the present invention, and FIG. 1 is a front view of the fuel injection pump, FIG. 2 is a vertical cross-sectional view taken in the direction of the - arrow in FIG. It is a partial cross-sectional front view showing the relationship. 1 is a fuel injection pump, 2 is a frame body, 3 is a cam drive shaft, 4 is a plunger pump, 5 is a cam body,
6 is a timing control sleeve, 7 is a tappet, 8 is a control gear, 13 is a sleeve,
14 is a plunger, 15 is a control pinion, 22 is a detector, and 29 is a governor which is an example of a fuel injection amount adjusting device.

Claims (1)

[Claims] 1. A short cylindrical frame, a cam drive shaft that is supported by the axial center of the frame with limited axial movement and rotates in conjunction with the rotation of the engine, and the cam drive shaft that is centered around the cam drive shaft. Each includes a sleeve arranged radially on the frame and fixed to the frame, and a plunger having a fuel metering function, which is slidably inserted into the shaft center of the sleeve and has a control pinion integrally attached thereto. a plurality of plunger pumps, a cam body fixed to the cam drive shaft;
a timing control sleeve rotatably fitted into the cam drive shaft, rotatable relative to the plurality of plunger pumps, and connected to a detector that detects at least the rotational speed of the engine and adjusts the injection timing; , a plurality of tappets slidably fitted into the timing control sleeve and arranged so as to face each plunger of the plunger pump and the cam surface of the cam body, respectively; and a plurality of tappets rotatably fitted to the cam drive shaft. A fuel injection pump comprising: a control gear that is fitted and meshed with the plurality of control pinions and rotates in conjunction with operation of the fuel injection amount adjusting device.