JPS6121571Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is designed to allow fuel oil supplied from a fuel inlet to flow into a plunger chamber through a feed valve, and pressurize the fuel oil by a plunger that reciprocates in conjunction with a servo piston. and a servo piston chamber inlet for introducing a portion of the supplied fuel, which becomes the working oil of the servo piston, into the servo piston chamber, which accommodates the servo piston; A servo piston chamber outlet is provided for discharging water from the servo piston chamber, and a conical valve is disposed facing the servo piston chamber inlet to open and close the servo piston chamber inlet and the servo piston chamber outlet in conjunction with each other. By introducing or discharging fuel oil into the conical valve chamber housing the conical valve, the conical valve closes or opens the inlet of the servo piston chamber, and the signal is transmitted in synchronization with the rotation of the engine. A solenoid valve driven by a solenoid coil whose excitation is controlled by an electric signal opens and closes a fuel inlet and a fuel outlet of the conical valve chamber, thereby introducing and discharging fuel into the conical valve chamber. The present invention relates to a pump nozzle for an internal combustion engine that can be controlled and further injects fuel oil pressurized by the plunger from a nozzle valve.

The pump nolls for internal combustion engines having the above-mentioned basic configuration were independently developed by the present applicant and a patent application was previously filed (Japanese Patent Application No. 168388-1988, etc.).
In the pump nolls for internal combustion engines according to the earlier application, there remained room for improvement in the points listed below.

That is, in the internal combustion engine pump nozzle according to the earlier application, (1) the plunger 20 as shown in FIGS. 1 and 2;
a plunger body 205 having a plunger chamber 201 for housing the servo piston 204; and a servo piston chamber 20 for housing the servo piston 204.
3, a conical valve body 208 having a conical valve chamber 207 for accommodating the conical valve 214, and a fuel inlet 20 for introducing fuel oil as hydraulic oil into the conical valve chamber 207.
9, a solenoid valve 212 for opening and closing the fuel inlet 209 and the fuel outlet 217, and the solenoid valve 2.
Solenoid coil 21 for driving 12
When the solenoid mechanism A formed by incorporating the solenoid structure A into the solenoid body 213 is sequentially disposed coaxially and integrally connected, first, the plunger body 205 and the servo piston body 206
and the conical valve body 208 are tightened in the axial direction with an appropriate number of connecting bolts 216, 216, . Since the valve body 208 and the solenoid body 213 of solenoid structure A are screwed together, the structure of the pump nolls is complicated, which makes disassembly and assembly of the pump nolls complicated.
Inspection, adjustment, repair, or parts replacement work is difficult. Connecting bolt 2 installed parallel to the axial direction of the nozzle
16, 216,... were used, it was necessary to secure a space in the thickness direction of the pump nozzle for mounting the coupling bolts 216, 216,..., and the pump nozzle became thicker by that amount. (3) Bolts 216, 21 connect the plunger body 205, servo piston body 206, conical valve body 208, and solenoid mechanism A.
In particular, plunger body 2 is connected by both means of screw engagement.
05 and the conical valve body 208 had problems such as having to form both a bolt hole and a threaded hole, which increased the number of processing steps and increased the manufacturing cost.

The present invention was made with the aim of improving the shortcomings of the pump nozzle for internal combustion engines according to the earlier application as described above, and in the pump nozzle for internal combustion engines having the basic configuration as shown in the header, the servo piston chamber and the plunger are A plunger body having a chamber, a conical valve body having a conical valve chamber, a solenoid valve seat having a fuel inlet, and a solenoid mechanism in which a solenoid coil and a solenoid valve are assembled in the solenoid body are assembled into a nut shape with a hole. The plunger body, conical valve body, solenoid valve seat, and solenoid mechanism can be integrally connected by sequentially coaxially housing the solenoid body in a connecting holder and screwing the solenoid body onto the connecting holder. The present invention is characterized by simplifying and compacting the structure and reducing manufacturing costs.

Below, the pump nozzle for internal combustion engines of the present invention will be described in the third section.
The explanation will be based on the embodiment shown in FIGS. 9 to 9. FIG. 3 shows a fuel injection device Z having a pump nozzle according to an embodiment of the present invention, which is mounted on the cylinder head of a diesel engine Y. .
This fuel injection device Z has a nozzle installed in a pump nozzle mounting hole 119 provided in a cylinder head 116 with the nozzle at its tip facing into hydraulic oil 118 formed above a piston 117 in a cylinder block 121. A controller that controls a pump nozzle X attached by a presser foot 120, a fuel supply pump 126 disposed outside the diesel engine Y, and a solenoid valve (described in detail later) housed in the pump nozzle. 129, the sensor 1 detects the rotational state of the engine by detecting the fuel in the fuel tank 125, which is sent into the pump nozzle X by the fuel supply pump 126 via the fuel pipe 114 and the fuel supply pipe 111.
controller 12 according to an input signal provided from 30.
9 controls the solenoid valve of the pump nozzle X to inject a predetermined amount of fuel into the working chamber 118.

Hereinafter, the structure of this pump nozzle X will be described in detail. As shown in FIG. 4, this pump nozzle A pump section 25 having a servo piston 27 and a control section 70 having a solenoid valve 71 for controlling a servo piston 27 of the pump section 25 are sequentially connected coaxially.

As shown in FIG. 4, the injection nozzle section 1 is composed of a nozzle body 3 into which a nozzle valve 2 is slidably inserted, a short-shaft nozzle stop spacer 4, and an injector cage 5. The nozzle valve 2 is fitted with a spring 7 in a nozzle spring seat fitting hole 6 which is formed to communicate with the nozzle stop spacer 4 and the injector cage 5.
A nozzle spring seat 8 is fitted which always biases the valve in the valve closing direction. This nozzle body 3
The nozzle stop spacer 4 and the injector cage 5 are integrally fastened to the tip of a plunger body 28, which will be described later, by means of a nozzle mounting nut 18.

Note that the end surface 4a of the nozzle stop spacer 4 on the nozzle body 3 side is the upper end surface 2a of the nozzle valve 2.
The upper limit of the lift of the nozzle valve 2 is controlled by the collision with the nozzle valve 2.

One end 12a of a high-pressure fuel passage 12 communicating with an oil reservoir chamber 11 formed at the tip of the nozzle body 3 is opened at the upper end surface 5a of the injector cage 5.

Note that one end 12a of this high-pressure fuel passage 12 is communicated with a plunger chamber 32 that opens at the lower end surface of a plunger body 28, which will be described later. or,
Between the upper end surface 5a of the injector cage 5 and the nozzle spring seat fitting hole 6, there is a nozzle for introducing fuel oil for biasing the nozzle valve 2 into the nozzle spring seat fitting hole 6, as described later. A diagonal hole 35 that becomes a part of a valve biasing fuel passage 36 is formed.

In FIG. 4, reference numeral 9 is a shim for adjusting the spring 7, and 13, 13, . . . are plunger body 2.
8, a parallel pin for positioning the injector cage 5 and the nozzle stop spacer 4 in the circumferential direction, 10
indicates each nozzle hole.

As shown in FIGS. 4, 5, and 7, the pump section 25 has a plunger chamber 32 for accommodating the plunger 26 and a servo piston chamber 31 for accommodating the servo piston 27 coaxially. Plunger bodies 28 formed to communicate with each other
and a conical valve body 29 having a conical valve chamber 40 for accommodating a conical valve 30, which will be described later, are coaxially connected. A large diameter servo piston 27 is fitted into the servo piston chamber 31, and a small diameter plunger 26 is fitted into the plunger chamber 32 so as to be slidable in the axial direction. The servo piston chamber 31 and the plunger chamber 32 are caused to integrally reciprocate in accordance with the pressure of the fuel flowing into and out of the chamber. This servo piston 27
The fuel injection pressure is determined by the cross-sectional area ratio of the plunger 26 and the plunger 26. Further, the servo piston chamber 31 and the plunger chamber 32 are each formed eccentrically relative to the axis of the plunger body 28 by an appropriate dimension.

The conical valve body 29 has a horizontal hole 38 of an appropriate depth formed in the radial direction from one side thereof, and the fuel supply pipe 111 is screwed into the outer end of the horizontal hole 38 .
This horizontal hole 38 is a passage for receiving the fuel pumped from the fuel supply pump 126, and hereinafter, this horizontal hole 38 will be referred to as the fuel supply passage 38.

Further, the inner part of the supply fuel passage 38 is slightly expanded to form a supply fuel chamber 39.

The conical valve body 29 includes a supply fuel chamber 3.
The conical valve chamber 40 communicates orthogonally with the valve chamber 9.
and a servo piston chamber inlet 64 are formed coaxially. This servo piston chamber inlet 64
The servo piston 27 is inserted into the servo piston chamber 31 from the servo piston chamber inlet 64.
The opening end surface on the fuel supply chamber 39 side serves as a conical valve seat 62 for a conical valve 30, which will be described later. On the other hand, the conical valve chamber 40 is connected to the supply fuel chamber 39 from the upper end surface of the conical valve body 29.
The conical valve chamber 4
A conical valve 30 for opening and closing the servo piston chamber inlet 64 is fitted into the inside of the conical valve 30 so as to be slidable in the axial direction.

The conical valve 30 is formed into a bottomed cylindrical shape with the supply fuel chamber 39 side closed, and is moved up and down by controlling the back pressure inside the conical valve chamber 40, and its tip is connected to the servo piston. The servo piston acts to open and close the chamber inlet 64 by being seated on or separated from the valve seat 62 of the chamber inlet 64 .

This conical valve 30 is always biased toward the conical valve seat 62 with an appropriate biasing force by a spring 51 fitted inside the conical valve 30.

Furthermore, an annular groove 5 of an appropriate width is formed on the sliding surface of the conical valve 30 against the chamber wall of the conical valve chamber 40.
7 is formed. When the conical valve 30 is closed, as shown in FIG. When the valve is open, the oil escape hole 5
The formation position in the axial direction is appropriately set so as to be in a non-communicating state at 6. One end of this oil escape hole 56 is communicated with the servo piston chamber 31 via the servo piston chamber outlet 65, and the other end is fitted into the outer peripheral surface of the conical valve body 29 and the outside of the conical valve body 29. It communicates with a return oil passage 60 formed between the inner circumferential surfaces of a connecting holder 69, which will be described later. Hereinafter, a series of oil passages 66 consisting of the servo piston chamber outlet 65 and the oil relief hole 56 will be referred to as a hydraulic oil relief passage 66.

By doing as described above, the conical valve 3
When valve 0 is opened, the servo piston chamber outlet 6
5 is closed, the fuel introduced into the servo piston chamber 31 from the servo piston chamber inlet 64 acts to move the servo piston 27 downward due to its fuel pressure, and the conical valve 30 is opened. When the servo piston chamber outlet 65 is opened, the servo piston 27 is connected to the plunger chamber 3 via a feed valve 45, which will be described later.
2 is moved upward by the pressure of the fuel introduced into it.

Further, as shown in FIG. 5, the conical valve body 29 has a vertical hole 49 extending in the axial direction so as to communicate with the fuel supply passage 38 thereof. This vertical hole 49
is the end surface 29a of the conical valve body 29 on the opening side of the conical valve chamber 40.
The end face 29b on the plunger body 28 side communicates with the upper groove 33 formed on the upper end face 28a of the plunger body 28. Furthermore, this upper groove 33 is connected to the plunger body 28 through a first vertical hole 41 formed in the plunger body 28.
8 is communicated with a feed valve chamber 42 formed in a deep hole shape from the lower end surface 28b side of the valve 8. Inside this feed valve chamber 42 is a feed valve 4 which is normally biased in the valve closing direction by a spring 46.
5 is fitted. Furthermore, this feed valve chamber 42 is connected to the lower end surface 28 of the plunger body 28.
It is communicated with the plunger chamber 32 by a lower groove 43 formed on the lower part b.

A series of oil passages 44 extending from the supply fuel passage 38 to the plunger chamber 32 through the vertical hole 49, further through the upper groove 33, the first vertical hole 41, the feed valve chamber 42, and the lower groove 43 are connected to the plunger chamber 32. This oil passage 44 serves as a passage for fuel to be filled into the chamber 32, and will be referred to as a fuel filling passage 44 hereinafter.

Also, the upper end surface 28a of this plunger body 28
The upper groove 33 formed on the upper side is connected to the second vertical hole 3 formed through the plunger body 28 as shown in FIG.
4 and the nozzle spring seat fitting hole 6 through the oblique hole 35 formed in the injector cage 5.
is communicated with. A series of oil passages 36 constituted by the vertical hole 49 of the conical valve body 29, the upper groove 33 of the plunger body 28, the second vertical hole 34, and the diagonal hole 35 of the injector cage 5.
(Fig. 4), since the opening pressure of the nozzle valve 2 is determined by the sum of the mounting load of the nozzle spring 7 and the back pressure load of the nozzle valve 2, the nozzle spring seat fitting hole is used to generate the back pressure. 6
Hereinafter, this oil passage 36 will be referred to as the nozzle valve biasing fuel passage 3.
It's called 6.

On the other hand, the conical valve chamber 40 has a disc-shaped solenoid valve seat 73 attached to its outer end surface.
One end is closed by the lower end surface of. This solenoid valve seat 73 has through holes 77 and 81 formed at its axial center and at positions closer to the outer periphery by an appropriate dimension from the axial center. These two through holes 7
7, 81, a through hole 77 formed in the shaft center part
As shown in FIG. 5, the groove 50 of the conical valve body 29 communicates with the fuel supply passage 38, and the lower recess 7 formed in the lower end surface of the solenoid spacer 88 placed on the upper part of the solenoid valve seat 73.
9 are communicated with each other. On the other hand, another through hole 81 formed closer to the outer periphery allows the lower recess 79 of the solenoid spacer 88 and the conical valve chamber 40 to communicate with each other.

That is, the through hole 77 near the outer periphery allows the fuel supplied into the supply fuel chamber 39 to be passed through the conical valve chamber 4.
It serves as a fuel inlet to introduce the fuel into the
Further, the through hole 81 formed in the axial center functions as a fuel intake/exhaust port for introducing fuel into the conical valve chamber 40 and discharging fuel within the conical valve chamber 40. Hereinafter, they will be referred to as a fuel inlet port 77 and a fuel intake/exhaust port 81, respectively. The upper end of the fuel inlet 77 is a valve seat 78 on which a solenoid valve 71, which will be described later, is seated.

Note that this valve seat 78 will be particularly referred to as the inflow side valve seat 78 below. By forming the fuel inlet 77 and the fuel inlet/outlet 81 as described above, when the fuel inlet 77 is open, the fuel in the supply fuel chamber 39 flows through the vertical hole 49 in the conical valve body 29 and the recess. The fuel enters the lower recess 79 of the solenoid spacer 88 from the groove 50 through the fuel inlet 77, and is further introduced into the conical valve chamber 40 through the fuel intake/exhaust port 81. Hereinafter, a series of oil passages 76 from this supply fuel chamber 39 to the conical valve chamber 40 will be referred to as the conical valve chamber fuel introduction passage 7.
6 (Figures 4 and 6).

Further, the conical valve body 29, the plunger body 28, and the solenoid valve seat 73 are housed in a connection holder 69 shaped like a cap nut with a hole. Circumferential grooves 58 are provided on the inner circumferential surface of the connection holder 69 and at two positions vertically sandwiching the supply fuel passage 38 of the conical valve body 29.
59 is formed. These circumferential grooves 58, 59
7 serves as a return oil passage 60 for returning discharged fuel from the servo piston chamber 31 and leakage oil from the plunger 26 and servo piston 27 to the fuel tank 125 side, and as shown in FIG. 58 communicates with one end of the oil escape hole 56, and the other end of the oil passage hole 55, which has one end open with the continuous portion 53 of the servo piston chamber 31 and the plunger chamber 32, communicates with the lower circumferential groove 59. There is.

Also, the supply fuel passage 38 of this connection holder 69
An annular gap 113 formed between each of the circumferential grooves 58 and 59 and between the fuel supply pipe attachment hole 112 of the cylinder head 116 and the fuel supply pipe 111 is located at the position where they overlap.
A through hole 54 is formed so as to communicate with both at the same time. This annular gap 113 serves as a passage for fuel discharged through the return oil passage 60, and hereinafter this will be referred to as the fuel return passage 1.
It's called 13. Further, a first fuel return pipe 115 is attached to the outer end of this fuel return path 113 (FIG. 3).

As shown in FIGS. 4 and 6, the control unit 70 includes a solenoid coil 72 whose excitation timing and excitation time are controlled by the controller 129, and an on-off valve driven by the attraction force of the solenoid coil 72. It has a solenoid valve 71.

The solenoid valve 71 is formed of a round rod body of an appropriate length, which has a lower valve element 83 and an upper valve element 84 in the shape of an oblique valve at both ends, and has a disc-shaped flange nearer to the upper valve element 84. 85 is formed. This solenoid valve 71 has a lower valve body 8 having a long rod body.
3 side is inserted into a straight cylindrical active core 90 in which a through hole 86 having a stepped inner peripheral surface is formed at its axial center from its small diameter inner peripheral surface side, and the flange 85 is inserted into the lower end opening of the through hole 86. It is accommodated in a recess 87 formed in the section. At this time, the lower end surface 9 of the active core 90
The depth of the recess 87 is set appropriately so that the lower end surface 85a of the flange 85 is flush with the lower end surface 85a of the flange 85.

In this way, the lower end surface 90a of the active core 90
and the lower end surface 85 of the flange 85 of the solenoid valve 71
When a is formed flush, the lower end surface 9 of the active core
0a and the lower end surface 85a of the collar of the solenoid valve 71
Since the leakage magnetic flux of the solenoid coil 72 is reduced as much as possible compared to the case where the solenoid coil 72 has a non-planar shape, the attractive force to the active core 90 is strengthened.

Further, a flanged, elongated cylindrical starter core 89 is fitted onto the lower valve body 83 side that protrudes downward from the lower end surface of the active core 90 with a lower spring 108 interposed between it and the active core 90. It is inserted. The static core 89 and the active core 90 are a core guide 9 in the shape of a slender cylinder with a flange.
The core is inserted into the core insertion hole 105 of No. 1. or,
The upper part of the core guide 91 is a small diameter threaded hole 107 that is continuous with the core insertion hole 105, and a fuel discharge port 103 is provided at the axial center of the threaded hole 107.
An upper sheet 74 having a shape formed thereon is fitted thereto.

The lower end opening of the fuel discharge port 103 serves as a valve seat 106 on which the upper valve element 84 of the solenoid valve 71 is seated. This valve seat 106
Since it is located in the path of fuel flowing out from the conical valve chamber 40, it will be particularly referred to as the outflow side valve seat 106 below. Further, between the upper seat 74 and the active core 90, the lower spring 1
An upper spring 109 having a spring constant and a load at the time of installation smaller than 08 is fitted.

At this time, the upper valve element 84 of the solenoid valve 71 is attached to the valve seat 106 of the upper seat 74, and the lower valve element 83 is attached to the solenoid valve seat 73.
The solenoid valves 7
1 is always urged toward the upper seat 74 together with the active core 90 due to the difference in spring force between the upper spring 109 and the lower spring 108, thereby closing the fuel discharge port 103.

In addition, this pump nozzle
The relative gap S in the axial direction between the active core 90 and the static core 89 when the active core 90 and the static core 89 are seated on the outflow side valve seat 106 is appropriately set. In this way, the valve lift h of the solenoid valve 71 can be adjusted to
0 and the static core 89 (i.e.,
If the maximum movable distance of the active core 90 is made smaller than the maximum movable distance of the active core 90, the upper surface 89a of the static core 89 and the lower surface 90a of the active core 90 will not come into close contact with each other as the solenoid valve 71 opens and closes. (That is, when the active core 90 moves upward), the active core 90 becomes easier to separate from the static core 89 side, and the operability of the active core 90 during high-speed rotation becomes better.

The static core 89 and the active core 90 each have an appropriate number of through holes 1 on their outer peripheries so as to overlap and communicate with each other in the axial direction.
01, 101, . . . 102, 2102, . . . are formed, respectively. These through holes 101, 10
1, . . . , 102, 102, . . ., the through holes 101, 101, .
02, 102, . . . are respectively communicated with the fuel discharge port 103 of the upper seat 74. Therefore, when the solenoid valve 71 moves downward to close the fuel inlet port 77 and open the fuel outlet port 103, the conical valve chamber 40 is connected to the upper recess 80 of the solenoid spacer 88 and the through hole 101 of the static core 89. , 101, . . . are communicated with the second fuel return pipe 123 through the through holes 102, 102, . A series of oil passages 100 from the conical valve chamber 40 to the second fuel return vibe 123 are connected to the conical valve chamber 4
This is for returning the hydraulic oil in the conical valve chamber 0 to the fuel tank 125 side, and hereinafter this will be referred to as the conical valve chamber fuel outflow passage 100.

A cylindrical solenoid coil 72 is fitted in an annular space formed between the solenoid body 92 and the core guide 91 to open and close the solenoid valve 71 by its suction force. The axial center of the solenoid coil 72 is located below the axial center of the active core 90 so that the active core 90 can be attracted and moved downward when the solenoid coil 72 is excited. Therefore, when the solenoid coil 72 is energized, the solenoid valve 71 is pulled down together with the active core 90 by its attractive force, and the lower valve body 83 closes the fuel inlet 77 and at the same time closes the fuel outlet 103. Open the door.

Furthermore, when the solenoid coil 72 becomes de-energized, its attractive force is released, so the solenoid valve 71 is pulled upward again due to the difference in spring force between the lower spring 108 and the upper spring 109, and the fuel inlet is closed. It acts to open the valve 77 and close the fuel discharge port 103 at the same time.

At this time, by screwing the upper seat 74 and changing the relative position in the axial direction with respect to the solenoid valve 71, the solenoid valve 7
The valve opening degree and valve stroke of No. 1 can be adjusted as appropriate.

Further, this control section 70 controls the static core 8
9. A solenoid body 9 in the form of a cap nut with a hole, together with an active core 90 and an upper seat 74, etc.
The solenoid body 92, the static core 89, the active core 90, the upper seat 74, and the like constitute a solenoid mechanism A. This solenoid mechanism A is integrally connected to the pump section 25 by screwing the solenoid body 92 of the solenoid mechanism A into the connection holder 69.

That is, the plunger body 28 of the pump section 25 and the conical valve body 29 are disposed within the connection holder 69.
and the solenoid valve seat 73 are sequentially housed coaxially so that the shoulder portion 28a of the plunger body 28 and the hooking portion 69a of the connecting holder 69 are engaged with each other in the axial direction, and the connecting holder 6
9, screw the male threaded part 97 formed on the outer peripheral surface of the lower end of the solenoid holder 92 of the solenoid structure A into the female threaded part 75 formed on the upper opening side of the solenoid structure A, and screw the solenoid structure A into the connection holder 69 side as appropriate. By applying an axial compressive force between the solenoid holder 92 of the solenoid mechanism A and the hook portion 69a of the connection holder 69, the solenoid mechanism A and each member of the pump section 25 are coupled in the axial direction.

In addition, the symbols 114, 114a, 114b, 114
c is a fuel pipe; 94 is a coupling nut 95 for integrally coupling the core guide 91 and the lower support 92; a lock nut of the upper sheet 74;
115, 115a, 115b, and 115c indicate second fuel return pipes.

Next, the operation and effect of the pump nozzle for an internal combustion engine according to the illustrated embodiment will be explained with reference to FIGS. 7 and 8 (simplified illustrations of a fuel injection device using the pump nozzle). The fuel injection device Z is connected to a fuel tank 125 by a fuel supply pump 126 driven by an internal combustion engine Y.
While supplying the fuel inside to pump nozzle X,
Depending on the rotational state of the internal combustion engine Y, a controller 129 controls the opening and closing of the solenoid valve 71 in the pump nozzle X as appropriate in accordance with a signal from a sensor 130 attached to a flywheel 131 thereof.

Note that the supply pressure of the supplied fuel is appropriately set by a pressure regulating valve 127, and the pressure pulsations thereof are absorbed by an accumulator 128.

First, referring to FIG. 8, the solenoid coil 72
To explain the operation of the pump nozzle X when the pump nozzle It acts to close the fuel inlet port 77 and open the fuel outlet port 103 at the same time.
When the fuel discharge port 103 opens, the fuel oil stored in the conical valve chamber 40 is discharged from the fuel intake/discharge port 81 of the conical valve chamber 40 through the fuel discharge passage 100 and then from the second fuel return pipe 123 to the fuel tank 125. It flows out to the side. When the fuel oil flows out from the conical valve chamber 40, a pressure difference is generated before and after the conical valve chamber 30, and the conical valve chamber 30 is moved upward by the fuel pressure in the supply fuel chamber 39, and the inlet 64 of the servo piston chamber 31 is moved up. Open the door. When the servo piston chamber inlet 64 is opened, the fuel in the supply fuel chamber 39 is introduced into the servo piston chamber 31.

At this time, since the servo piston chamber outlet 65 is closed by the sliding surface of the conical valve 30, when the servo piston 27 is pushed downward by the fuel pressure, the plunger 26 is also pushed downward together with the servo piston 27. When the plunger 26 is moved downward, the plunger chamber 32
The fuel oil in the nozzle body 3 is pressurized, and the feed valve 45 is closed by the fuel pressure. At the same time, the fuel pressure in the oil reservoir 11 formed in the nozzle body 3 is suddenly increased, and the nozzle valve 2 is opened. The fuel in the plunger 32 is sequentially discharged from the nozzle holes 10, 10, ... through the high-pressure fuel passage 12 to the working chamber 11.
When the plunger 26 reaches the lower lift limit position, the fuel pressure in the fuel reservoir 11 drops, and the spring 7 acting on the nozzle valve 2 decreases.
The nozzle valve 2 is closed by the biasing force of the nozzle spring 31 and the pressure of the fuel oil that has flowed into the nozzle spring seat fitting hole 6 via the nozzle valve biasing fuel passage 36, and the fuel injection is terminated.

Next, referring to FIG. 9, the solenoid coil 72
To explain the operation of the pump nozzle X when the current is cut off from the energized state, the solenoid valve 71
Since the suction force is released, the solenoid valve 71 is moved upward by the spring force, opening the fuel inlet 77 of the conical valve chamber 40 and closing the fuel outlet 103. When the fuel inlet 77 is opened, the fuel oil in the supply fuel chamber 39 flows into the conical valve chamber 40, the fuel pressures before and after the conical valve 30 are balanced, and the conical valve 30 is moved by the spring force of the spring 51. As a result, it is moved downward, and the servo piston chamber inlet 64 is closed. When the conical valve 30 moves downward, the annular groove 57 formed on its sliding surface communicates with the oil escape hole 56, so the servo piston chamber outlet 65 is opened, and the fuel oil in the servo piston chamber 31 is discharged from the hydraulic oil. It flows out to the fuel tank 125 side through the relief passage 66, and the pressure in the servo piston chamber 31 drops. Then, the pressure inside the plunger chamber 32 also drops accordingly. To this end, the high-pressure fuel oil in the fuel filling passage 44 pushes open the feed valve 45 and flows into the plunger chamber 32, further moving the plunger 26 and servo piston 27 upward.

By sequentially repeating the injection process shown in FIG. 8 and the filling process shown in FIG. 9, the internal combustion engine Y is continuously operated.

Further, the injection amount of the pump nozzle X is determined by the fuel filling time, that is, the return stroke length of the plunger 26 and the return speed of the servo piston 27. This filling time is adjusted by appropriately setting the energization cutoff time of the solenoid coil 72.

Next, to explain the effect of the present invention, the pump nozzle for an internal combustion engine of the present invention has a solenoid mechanism that is screwed onto a connecting holder that accommodates each member of the pump section, so that each member of the pump section can be connected to the solenoid. Since the structure A can be connected in the axial direction, it is possible to connect the mechanism A in the axial direction, compared to the case where the pump nozzle for the internal combustion engine of the earlier application shown in FIG. 1 and FIG. Its structure is simple and it can be easily disassembled and reassembled, and has the effect of simplifying inspection, adjustment, repair, and parts replacement work.

In addition, as a means of connecting each member of the pump part and the solenoid mechanism, a connecting bolt is not used as in the pump nozzle for an internal combustion engine related to the earlier application, so the space for installing the connecting bolt is limited to the radial direction of the pump nozzle. There is no need to bulge the pump nozzle, and the pump nozzle can be made slimmer and more compact.

Furthermore, since each member of the pump section and the solenoid mechanism are connected only by screw engagement, there is no need to form bolt holes in each member as in the pump nozzle for internal combustion engines of the earlier application. This has the practical effect of reducing manufacturing costs by reducing the number of processing steps.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of a pump nozzle for an internal combustion engine according to the earlier application, Fig. 2 is a longitudinal sectional view of the main part of Fig. 1, and Fig. 3 is a pump nozzle for an internal combustion engine according to an embodiment of the present invention installed. FIG. 4 is a vertical sectional view of the main part of an internal combustion engine having a fuel injection device shown in FIG. 3, FIG. 5 is a vertical sectional view of the main part of FIG. Figure 4 is an enlarged view of the part, Figure 7 is a vertical sectional view of Figure 5, Figures 8 and 9 are Figure 3.
FIG. 3 is an explanatory diagram of the operation of the pump nozzle shown in the figure. 2... Nozzle valve, 26... Plunger, 2
7... Servo piston, 28... Plunger body, 29... Conical valve body, 30... Conical valve, 31... Servo piston chamber, 32
... Plunger chamber, 38 ... Fuel inlet, 40 ...
Conical valve, 45...Feed valve, 64
...Servo piston chamber inlet, 65...Servo piston chamber outlet, 69...Connection holder, 71...
... Solenoid valve, 72 ... Solenoid coil, 73 ... Solenoid valve seat, 77 ...
Fuel inlet, 92...Solenoid body, 103
...Fuel outlet, A...Solenoid mechanism.

Claims (1)

[Scope of utility model registration request] The fuel oil supplied from the fuel inlet 38 is made to flow into the plunger chamber 32 via the feed valve 45, and is pressurized by the plunger 26 which reciprocates in conjunction with the servo piston 27. A servo piston chamber inlet 64 is provided for introducing a portion of the supplied fuel, which becomes the working oil for the servo piston 27, into the servo piston chamber 31 that accommodates the piston 27; A servo piston chamber outlet 65 for discharging air from the chamber 31 is provided, while the servo piston chamber inlet 64
In this step, a conical valve 30 that opens and closes the servo piston chamber inlet 64 and the servo piston chamber outlet 65 in conjunction with each other is disposed facing each other, and fuel oil is introduced into the conical valve chamber 40 that accommodates the conical valve 30. Or, by discharging the conical valve 30, the servo piston chamber inlet 64 and the servo piston chamber outlet 65 are closed or opened, respectively, and an electric signal is transmitted in synchronization with the rotation of the engine. The fuel inlet 77 and fuel outlet 103 of the conical valve chamber 40 are opened and closed by a solenoid valve 71 driven by a solenoid coil 72 which is excited and controlled, thereby introducing and discharging fuel into the conical valve chamber 40. controllably and further introduce fuel oil into the plunger chamber 32;
The solenoid valve 71 opens the fuel inlet 77 of the conical valve chamber 40 to introduce fuel into the conical valve chamber 40, and the conical valve 30 opens the servo piston chamber inlet 6.
4 and the servo piston chamber outlet 65
This is done by opening the servo piston chamber 31 to discharge the hydraulic oil from the servo piston chamber 31 and moving the plunger 26 together with the servo piston 27 in the fuel introduction direction, and pressurizing the fuel introduced into the plunger chamber 32. and injection into the conical valve chamber 4 by the solenoid valve 71.
0 to open the fuel outlet 103 to discharge fuel from the conical valve chamber 40, open the conical valve 30 to open the servo piston chamber inlet 64, and close the servo piston chamber outlet 65. Introducing fuel into the servo piston chamber 31, moving the plunger 26 together with the servo piston 27 to the fuel pressurizing side, and injecting the pressurized fuel from the nozzle valve 2 that opens according to the fuel pressure. This is a pump nozzle for an internal combustion engine, which includes a plunger body 28 having the servo piston chamber 31 and the plunger chamber 32, and the conical valve chamber 4.
0 and a solenoid valve seat 7 having the fuel inlet 77.
3 and a solenoid mechanism A in which the solenoid coil 72 and the solenoid valve 71 are assembled in a solenoid body 92 are sequentially coaxially housed in a cap nut-shaped connection holder 69 with a hole, and the solenoid mechanism A is installed in the connection holder 69. On the other hand, the solenoid body 9
2 by screwing the plunger body 2.
8, a conical valve body 29, a solenoid valve seat 73, and a solenoid mechanism A can be integrally combined.