JP5933382B2 - Electromagnetic drive device and high-pressure pump using the same - Google Patents

Description

  The present invention relates to an electromagnetic drive device and a high-pressure pump using the same.

Conventionally, a high-pressure pump that pressurizes fuel supplied to an internal combustion engine is known. The high-pressure pump communicates or shuts off a pump chamber that pressurizes fuel by a reciprocating movement of a plunger and a fluid chamber that supplies the pump chamber with a suction valve. The high-pressure pump includes an electromagnetic drive device that controls the operation of the suction valve.
In the high-pressure pump described in Patent Document 1, a needle valve in which a suction valve and a drive shaft are integrated is connected to a movable core of an electromagnetic drive device. A communication hole communicating with the movable core chamber and the fluid chamber is provided in one of the valve body and the flange that separates the movable core chamber and the fluid chamber in which the movable core is accommodated. With this communication hole, the movable core chamber functions as a damper that reduces noise caused by a collision between a valve seat provided in the fluid chamber and the needle valve.

JP 2001-304068 A

Incidentally, in the electromagnetic drive device described in Patent Document 1, when the movable core is magnetically attracted to the fixed core, a positive vibration force is generated from the gap between the movable core and the fixed core. This exciting force excites the fuel in the gap between the inner wall of the movable core chamber and the movable core and the fuel in the communication hole. Then, when the vibrated fuel mass rapidly flows out from the communication hole to the fluid chamber, a negative reflected wave (hereinafter referred to as “generated negative pressure”) is generated at the opening end of the communication hole on the fluid chamber side. When the fuel in the movable core chamber becomes equal to or lower than the saturated vapor pressure due to the generated negative pressure, the volume ratio of cavitation in the movable core chamber increases, and erosion may occur on the movable core and the inner wall of the movable core chamber.
The present invention has been made in view of the above problems, and an object thereof is to provide an electromagnetic drive device capable of suppressing erosion and a high-pressure pump using the electromagnetic drive device.

The present invention provides an electromagnetic driving device in which a partition that separates a movable core chamber and a fluid chamber has a communication hole that communicates the movable core chamber and the fluid chamber. It is more than the cross-sectional area of the core flow path provided in the moving direction . Furthermore, the cross-sectional area of the communication hole which the partition part has is 1.0 to 2.3 times the cross-sectional area of the core flow path.

  When the movable core is magnetically attracted to the fixed core, the excitation force generated in the gap between the movable core and the fixed core excites the fluid in the core channel and the communication hole. If the cross-sectional area of the communication hole is large, the fluid mass of the communication hole to be vibrated is large. Therefore, the speed at which the fluid mass flows out to the fluid chamber is reduced, and the amplitude of the generated negative pressure generated at the open end of the communication hole on the fluid chamber side is reduced. Therefore, the volume ratio of cavitation in the movable core chamber can be reduced, and erosion of the movable core and the inner wall of the movable core chamber can be suppressed.

1 is a cross-sectional view of a high pressure pump according to a first embodiment of the present invention. The principal part enlarged view of FIG. The principal part enlarged view of FIG. 2, and the figure of its equivalent model. Sectional drawing of the IV-IV line of FIG. Explanatory drawing when the cross-sectional area of a communicating hole is less than 1.0 times the cross-sectional area of a core flow path. Explanatory drawing when the cross-sectional area of a communicating hole is 1.0 time the cross-sectional area of a core flow path. Explanatory drawing when the cross-sectional area of a communicating hole is 1.0 time the cross-sectional area of a core flow path. Explanatory drawing when the cross-sectional area of a communicating hole is larger than 1.0 of the cross-sectional area of a core flow path, and is 2.3 times or less. Explanatory drawing when the cross-sectional area of a communicating hole is larger than 1.0 of the cross-sectional area of a core flow path, and is 2.3 times or less. Explanatory drawing when the cross-sectional area of a communicating hole is larger than 2.3 times the cross-sectional area of a core flow path. Explanatory drawing when the length of a communicating hole is less than 0.8 times the length of a core flow path. Explanatory drawing when the length of a communicating hole is 0.8 to 1.2 times the length of a core flow path. Explanatory drawing when the length of a communicating hole is larger than 1.2 times the length of a core flow path. The graph which shows the relationship between a communicating hole cross-sectional area ratio and a cavitation volume ratio. The graph which shows the relationship between a communicating hole length ratio and a cavitation volume ratio. Sectional drawing of the principal part of the high pressure pump by 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A first embodiment of the present invention is shown in FIGS. The electromagnetic drive device 10 of this embodiment is used for the high-pressure pump 1. The high-pressure pump 1 is provided in a fuel supply system that supplies fuel to the internal combustion engine, pressurizes the fuel pumped up from the fuel tank, and accumulates the pressure in the delivery pipe. The fuel accumulated in the delivery pipe is injected and supplied from the injector to each cylinder of the internal combustion engine. The fuel of the present embodiment corresponds to “fluid” recited in the claims.

(Configuration of high-pressure pump and electromagnetic drive)
As shown in FIG. 1, the high-pressure pump 1 includes a pump body 20, a plunger 21, a damper chamber 30, a suction valve unit 40, an electromagnetic drive device 10, a discharge valve unit 60, and the like.
The pump body 20 is provided with a cylindrical cylinder 22. A plunger 21 is accommodated in the cylinder 22 so as to be capable of reciprocating in the axial direction. A spring 26 is provided between a spring seat 23 provided at an end of the plunger 21 protruding from the pump body 20 and an oil seal holder 25 that holds an oil seal 24 on the outer periphery of the plunger 21. By this spring 26, the plunger 21 is urged toward the camshaft side of the engine (not shown). Therefore, the plunger 21 reciprocates in the axial direction according to the cam profile of the camshaft. By the reciprocating movement of the plunger 21, the volume of the pump chamber 27 is changed, so that fuel is sucked and pressurized.

Next, the damper chamber 30 will be described.
The pump body 20 is provided with a cylindrical cylindrical portion 31 that protrudes on the opposite side of the cylinder 22. The damper chamber 30 is formed by covering the cylindrical portion 31 with the bottomed cylindrical cover 32.
A pulsation damper 33 and a support member 34 are accommodated in the damper chamber 30.
The pulsation damper 33 is composed of two metal diaphragms, and a gas having a predetermined pressure is sealed therein. The pulsation damper 33 reduces the fuel pressure pulsation in the damper chamber 30 by elastically deforming the two metal diaphragms according to the pressure change in the damper chamber 30.

  The damper chamber 30 communicates with a fuel inlet (not shown) through a fuel passage (not shown). Fuel is supplied to the fuel inlet from a fuel tank (not shown). Therefore, the damper chamber 30 is supplied with fuel from the fuel tank from the fuel inlet.

Next, the suction valve unit 40 will be described.
The suction valve unit 40 is composed of a valve body 41, a suction valve stopper 42, a suction valve 43, and the like.
The pump body 20 is provided with a recess 28 substantially perpendicular to the central axis of the cylinder 22. By covering the opening of the recess 28 with the flange 11, the fluid chamber 44 from the damper chamber 30 to the pump chamber 27 is defined. The flange 11 and the pump body 20 of the present embodiment correspond to a “housing” described in the claims.

  As shown in FIG. 2 or 3, the valve body 41 is fitted into the inner wall of the fluid chamber 44. A shaft portion 431 of the suction valve 43 is supported in a reciprocating manner in a hole 47 provided in the axial direction of the valve body 41. The valve body 41 has an annular valve seat 46 inside. The intake valve 43 can be seated on and separated from the valve seat 46. The fluid chamber 44 is closed when the suction valve 43 is seated on the valve seat 46, and the fluid chamber 44 is opened when the suction valve 43 is separated from the valve seat 46.

The suction valve stopper 42 is provided inside the valve body 41 on the pump chamber side of the suction valve 43. The suction valve stopper 42 restricts the movement of the suction valve 43 on the pump chamber side (the valve opening direction). The suction valve stopper 42 has a hole 48 through which fuel can flow.
A first spring 45 is provided between the suction valve stopper 42 and the suction valve 43. The first spring 45 urges the suction valve 43 toward the valve seat (in the valve closing direction).

Next, the electromagnetic drive device 10 will be described.
The electromagnetic drive device 10 includes a flange 11, a drive shaft 12, a fixed core 13, a movable core 14, a coil 15, and the like.
The flange 11 has a partition 17 that separates the movable core chamber 16 that houses the movable core 14 and the fluid chamber 44. The partition portion 17 has a communication hole 4 that allows the movable core chamber 16 and the fluid chamber 44 to communicate with each other.
A guide tube 19 is provided inside a hole provided in the center of the partition portion 17. The drive shaft 12 is supported by the partition portion 17 through the guide cylinder 19 so as to be able to reciprocate. One end of the drive shaft 12 is fixed to the movable core 14, and the other end can be brought into contact with or separated from the suction valve 43.

  The movable core 14 is made of a magnetic material and is accommodated in a movable core chamber 16 provided inside the flange 11 so as to be capable of reciprocating in the axial direction. The movable core 14 has a plurality of breathing holes 50 communicating with the moving direction. As shown in FIG. 4, the movable core 14 is provided with a plurality of breathing holes 50. Further, a gap 51 in which the movable core 14 can reciprocate is provided between the inner wall of the movable core chamber 16 and the movable core 14. Hereinafter, the gap 51 between the inner wall of the movable core chamber 16 and the movable core 14 and the breathing hole 50 are collectively referred to as a core flow path 3.

FIG. 3 shows an equivalent model of the core flow path 3 and the communication hole 4. The cross-sectional area of the core channel 3 in the equivalent model is the sum of the cross-sectional area of the gap 51 between the inner wall of the movable core chamber 16 and the movable core 14 and the cross-sectional area of the breathing hole 50. The length of the core channel 3 in the equivalent model is the length from the end surface on the fixed core side of the movable core 14 to the end surface on the movable core side of the partition portion 17.
The cross-sectional area of the communication hole 4 in the equivalent model is the sum of the cross-sectional areas of the plurality of communication holes 4. The length a of the communication hole 4 in the equivalent model is the same as the length a from the opening on the movable core chamber side of the communication hole 4 to the opening on the fluid chamber side.
The cross-sectional area of the communication hole 4 is 1.0 to 2.3 times the cross-sectional area of the core flow path 3. Further, the length of the communication hole 4 is 0.8 to 1.2 times the length of the core flow path 3. The core flow path 3 includes a space 52 between the end surface of the movable core 14 on the communication hole side and the end surface of the flange 11 on the movable core side.

The fixed core 13 is made of a magnetic material, and is provided with a flange 11 and an annular portion 53 made of a nonmagnetic material interposed therebetween. The fixed core 13 is provided with a first spring accommodation hole 54. The movable core 14 is provided with a second spring accommodation hole 55. A second spring 56 is provided in the first spring accommodation hole 54 and the second spring accommodation hole 55. The second spring 56 biases the movable core 14 toward the pump chamber with a stronger force than the first spring 45.
Note that the second spring 56 of the present embodiment corresponds to “biasing means” described in the claims.

A connector 57 is provided outside the diameter of the fixed core 13. The connector 57 is held by a bottomed cylindrical yoke 58. The yoke 58 is fixed to the flange 11.
The coil 15 is wound around a bobbin 59 provided inside the connector 57. When the coil 15 is energized through the terminal 571 of the connector 57, the coil 15 generates a magnetic field.

When the coil 15 is not energized, the movable core 14 and the fixed core 13 are separated from each other by the elastic force of the second spring 56. The drive shaft 12 moves to the pump chamber side, and the suction valve 43 opens when the end surface of the drive shaft 12 presses the suction valve 43.
When the coil 15 is energized, magnetic flux flows through the magnetic circuit formed by the fixed core 13, the movable core 14, the yoke 58 and the flange 11, and the movable core 14 resists the elastic force of the second spring 56, and the fixed core side. Is magnetically attracted. As a result, the drive shaft 12 releases the pressing force on the suction valve 43.

Next, the discharge valve unit 60 will be described.
As shown in FIG. 1, the discharge valve portion 60 includes a discharge valve 61, a regulating member 62, a spring 63, and the like.
A discharge passage 64 is formed in the pump body 20 substantially perpendicular to the central axis of the cylinder 22. The discharge valve 61 is accommodated in the discharge passage 64 so as to be able to reciprocate. The discharge valve 61 opens or closes the discharge passage 64 by being seated on or separated from the valve seat 65.
The regulating member 62 provided on the fuel discharge port 66 side of the discharge valve 61 regulates the movement of the discharge valve 61 to the fuel discharge port 66 side.
One end of the spring 63 is in contact with the regulating member 62, the other end is in contact with the discharge valve 61, and the discharge valve 61 is urged toward the valve seat.

The pressure of the fuel in the pump chamber 27 increases, and the force that the discharge valve 61 receives from the fuel on the pump chamber side is the sum of the spring force of the spring 63 and the force that the discharge valve 61 receives from the fuel on the downstream side of the valve seat 65. Also, the discharge valve 61 moves away from the valve seat 65. As a result, fuel is discharged from the fuel discharge port 66.
On the other hand, the pressure of the fuel in the pump chamber 27 decreases, and the force that the discharge valve 61 receives from the fuel on the pump chamber side is the sum of the spring force of the spring 63 and the force that the discharge valve 61 receives from the fuel on the downstream side of the valve seat 65. When smaller than this, the discharge valve 61 is seated on the valve seat 65. This prevents fuel on the downstream side of the valve seat 65 from flowing back to the pump chamber 27.

(High pressure pump operation)
Next, the operation of the high pressure pump 1 will be described.
(1) Suction stroke When the plunger 21 is lowered from the top dead center toward the bottom dead center by the rotation of the camshaft, the volume of the pump chamber 27 increases and the fuel is depressurized. The discharge valve 61 is seated on the valve seat 65 and closes the discharge passage 64.
On the other hand, the suction valve 43 moves to the pump chamber side against the urging force of the first spring 45 due to the pressure difference between the pump chamber 27 and the fluid chamber 44 and is opened. At this time, since energization to the coil 15 is stopped, the drive shaft 12 integrated with the movable core 14 moves to the pump chamber side by the urging force of the second spring 56 and presses the suction valve 43 to the pump chamber side. To do. Therefore, the intake valve 43 maintains the valve open state. As a result, fuel is sucked into the pump chamber 27 from the damper chamber 30 via the fluid chamber 44.

(2) Metering stroke When the plunger 21 rises from the bottom dead center toward the top dead center due to the rotation of the camshaft, the volume of the pump chamber 27 decreases. At this time, since energization to the coil 15 is stopped until a predetermined time, the drive shaft 12 and the suction valve 43 are in the open position by the urging force of the second spring 56. Thereby, the fluid chamber 44 is maintained in an open state. For this reason, the low-pressure fuel once sucked into the pump chamber 27 is returned to the damper chamber 30 via the fluid chamber 44. Therefore, the pressure in the pump chamber 27 does not increase.

(3) Pressurization stroke The coil 15 is energized at a predetermined time while the plunger 21 rises from the bottom dead center toward the top dead center. Then, a magnetic attractive force is generated between the fixed core 13 and the movable core 14 by the magnetic field generated in the coil 15. When this magnetic attractive force becomes larger than the difference between the elastic force of the second spring 56 and the elastic force of the first spring 45, the movable core 14 and the drive shaft 12 move to the fixed core side. Thereby, the pressing force of the drive shaft 12 on the suction valve 43 is released. The suction valve 43 moves to the valve seat side by the elastic force of the first spring 45 and the force generated by the flow of low-pressure fuel discharged from the pump chamber 27 to the damper chamber side. Therefore, the suction valve 43 is seated on the valve seat 46 and the fluid chamber 44 is closed.

From the time when the intake valve 43 is seated on the valve seat 46, the fuel pressure in the pump chamber 27 increases as the plunger 21 rises toward the top dead center. When the force that the fuel pressure in the pump chamber 27 acts on the discharge valve 61 becomes larger than the force that the fuel pressure in the discharge passage 64 acts on the discharge valve 61 and the urging force of the spring 63, the discharge valve 61 opens. As a result, the high-pressure fuel pressurized in the pump chamber 27 is discharged from the fuel discharge port 66 via the discharge passage 64.
Note that energization of the coil 15 is stopped during the pressurization stroke. Since the force that the fuel pressure in the pump chamber 27 acts on the suction valve 43 is larger than the biasing force of the second spring 56, the suction valve 43 maintains the closed state.
The high-pressure pump 1 repeats steps (1) to (3) to pressurize and discharge a necessary amount of fuel to the internal combustion engine.

(Cross-sectional area of communication hole)
Next, the relationship between the sectional area of the communication hole 4 and the generated negative pressure will be described.
Hereinafter, in FIGS. 5 to 11, an equivalent model of the core flow path 3 and the communication hole 4 is shown in the center of the figure, a positive vibration force is shown on the right side of the equivalent model, and a generated negative pressure is shown on the left side of the equivalent model. Indicates. In the equivalent model, the upper side of FIGS. 5 to 11 shows the core flow path 3 and the lower side shows the communication hole 4.

(1) FIG. 5 shows an excitation force A and a generated negative pressure B when the cross-sectional area of the communication hole 4 is less than 1.0 times the cross-sectional area of the core flow path 3 (hereinafter referred to as “case 1”). It shows.
When the movable core is magnetically attracted to the fixed core, the fuel mass in the gap between the movable core and the fixed core tends to flow out from the core flow path 3 through the communication hole 4 to the fluid chamber. This outflow is a positive pressure and becomes an oscillating force. The vibration force A generated in the gap in the case 1 is small because the amount of the fuel mass α of the communicating hole 4 to be vibrated is small. However, since the speed with which the small amount of fuel mass α flows out to the fluid chamber increases, the amplitude of the generated negative pressure generated at the opening end of the communication hole 4 on the fluid chamber side becomes large. Therefore, in the case 1, the generated negative pressure B of the movable core chamber having the core flow path 3 is increased.

(2) FIG. 6 shows the excitation force C and the generated negative pressure D when the cross-sectional area of the communication hole 4 is 1.0 times the cross-sectional area of the core flow path 3 (hereinafter referred to as “case 2”). Indicates. In FIG. 6, the excitation force in the case 1 described above is indicated by a broken line A, and the generated negative pressure is indicated by a broken line B.
FIG. 7 shows the excitation force C and the generated negative pressure D in case 2 including the time axis.

In the case 2, the amount of the fuel mass β in the core flow path 3 and the communication hole 4 to be vibrated is larger than the amount of the fuel mass α in the case 1 described above. Therefore, the excitation force C generated from the gap in the case 2 is larger than the excitation force A in the case 1.
However, in the case 2, the speed at which the excited fuel mass β flows out to the fluid chamber is slower than in the case 1, and the amplitude of the generated negative pressure D generated at the open end of the communication hole 4 on the fluid chamber side. Becomes smaller. Therefore, in the case 2, the generated negative pressure D in the movable core chamber having the core flow path 3 is smaller than the generated negative pressure B in the case 1.

(3) FIG. 8 shows vibration generation when the cross-sectional area of the communication hole 4 is larger than 1.0 times and smaller than 2.3 times the cross-sectional area of the core flow path 3 (hereinafter referred to as “case 3”). A force E, generated negative pressures F and G, and a composite negative pressure wave H are shown.
FIG. 9 shows the vibration force E, the generated negative pressures F and G, and the combined negative pressure wave H in case 3 including the time axis.

In case 3, the excitation force E generated from the gap in case 3 is substantially the same as the excitation force C in case 2.
However, in the case 3, the excited fuel mass is divided into a fuel mass γ in the core flow path 3 and a fuel mass δ in the communication hole 4. Therefore, the excitation force E generated from the gap is generated by the generated negative pressure F reflected at the opening end on the communication hole side of the core flow path 3 and the generated negative pressure G reflected at the opening end on the fluid chamber side of the communication hole 4. Divided. The amplitudes of the two generated negative pressures F and G are smaller than the amplitude of the excitation force E. In addition, since the two generated negative pressures F and G have a phase difference, the amplitude b of the combined negative pressure wave H obtained by combining the two generated negative pressures F and G is relative to the amplitude of the excitation force E. It will be small. Therefore, in the case 3, the composite negative pressure wave H in the movable core chamber having the core flow path 3 is smaller than the generated negative pressure D in the case 2.

(4) FIG. 10 shows the excitation force I and the generated negative pressure when the cross-sectional area of the communication hole 4 is larger than 2.3 times the cross-sectional area of the core flow path 3 (hereinafter referred to as “case 4”). J. In FIG. 10, the excitation force in the case 3 described above is indicated by a broken line E.
In the case 4, the fuel mass to be vibrated is only the fuel mass ε of the core flow path 3. The fuel mass in the communication hole 4 becomes excessive with respect to the vibration force I and acts as a material that attenuates the vibration force I. Therefore, the excitation force I generated from the gap in the case 4 is smaller than the excitation force in the case 3.
However, in the case 4, the fuel mass to be vibrated is only the fuel mass ε of the core flow path 3, and is smaller than the fuel mass to be vibrated in the case 3. Therefore, the speed at which the fuel mass ε flows out to the communication hole 4 is increased, and the amplitude c of the generated negative pressure J generated at the open end of the core channel 3 on the communication hole side is substantially the same as the amplitude of the excitation force I. It becomes. Therefore, in the case 4, the generated negative pressure J in the movable core chamber having the core flow path 3 is larger than the combined negative pressure wave H in the case 3.

(Length of communication hole 4)
Next, the relationship between the length of the communication hole 4 and the generated negative pressure will be described.
Hereinafter, FIGS. 11 to 13 are obtained by changing the lengths of the core flow path 3 and the communication hole 4 based on the case 3 described above.
(5) FIG. 11 shows an excitation force K and a generated negative pressure L when the length of the communication hole 4 is less than 0.8 times the length of the core flow path 3 (hereinafter referred to as “case 5”). , M and the composite negative pressure wave N. In FIG. 11, the excitation force in the case 3 described above is indicated by a broken line E.
In the case 5, the excited fuel mass is divided into a fuel mass ζ in the core flow path 3 and a fuel mass η in the communication hole 4. In the case 5, the length of the communication hole 4 is shorter than in the case 3, so that the amount of fuel mass ζ and η to be oscillated is smaller than the amount of fuel mass γ and δ in case 3. Therefore, the excitation force K generated from the gap in the case 5 is smaller than the excitation force E in the case 3.
However, in the case 5, since the amount of the fuel mass ζ, η in the core flow path 3 and the communication hole 4 is small, the speed at which the fuel mass ζ, η flows into the fluid chamber is increased. The amplitudes of the generated negative pressures L and M generated at the opening end on the communication hole side and the opening end on the fluid chamber side of the communication hole 4 are increased.
Moreover, since the phase difference between the generated negative pressure L reflected at the opening end on the communication hole side of the core channel 3 and the generated negative pressure M generated at the opening end on the fluid chamber side of the communication hole 4 is small, two generation negative pressures are generated. The amplitude d of the combined negative pressure wave N obtained by combining the pressures L and M is larger than the amplitude b of the combined negative pressure wave H in the case 3.

(6) FIG. 12 shows an excitation force E when the length of the communication hole 4 is 0.8 to 1.2 times the length of the core flow path 3 (hereinafter referred to as “case 6”). , The generated negative pressures F and G and the composite negative pressure wave H are shown.
The case 6 is the same as the case 3 and will not be described.

(7) FIG. 13 shows the excitation force O and the generated negative pressure when the length of the communication hole 4 is larger than 1.2 times the length of the core flow path 3 (hereinafter referred to as “case 7”). P. In FIG. 13, the excitation force in the case 6 described above is indicated by a broken line E.
In the case 7, the fuel mass to be vibrated is only the fuel mass θ of the core flow path 3. The fuel mass in the communication hole 4 is excessive with respect to the vibration force O, acts as a damping force for the vibration force O, and is hardly vibrated. Therefore, the excitation force O generated from the gap in the case 7 is smaller than the excitation force E in the case 6.
However, in the case 7, the fuel mass to be vibrated is as small as the fuel mass θ of the core flow path 3 alone. Therefore, the speed at which the fuel mass θ flows out to the communication hole 4 is increased, and the amplitude e of the generated negative pressure P generated at the open end of the core flow path 3 on the communication hole side is substantially the same as the amplitude of the excitation force O. become. Therefore, in the case 7, the generated negative pressure P in the movable core chamber having the core flow path 3 is larger than the combined negative pressure wave H in the case 6.

(Cross sectional area of communication hole and cavitation volume ratio)
Next, the relationship between the cross-sectional area of the communication hole and the cavitation volume ratio will be described.
FIG. 14 is a graph with the cross-sectional area ratio of the communication holes as the horizontal axis and the cavitation volume ratio of the movable core chamber as the vertical axis. The communication hole cross-sectional area ratio refers to the ratio of the cross-sectional area of the communication hole 4 to the cross-sectional area of the core channel 3.
In FIG. 14, a solid line S1 indicates the cavitation volume ratio when the cross-sectional area perpendicular to the axis of the movable core has a predetermined size.
The solid line S2 indicates the cavitation volume ratio when the cross-sectional area perpendicular to the axis of the movable core is 0.75 times similar to that of the solid line S1.
A solid line S3 indicates a cavitation volume ratio in a case where the cross-sectional area perpendicular to the axis of the movable core is 1.25 times similar to that of the solid line S1.
From the graph of FIG. 1 4, regardless of the cross-sectional area of the movable core, communicating Anadan area ratio when 1.0 to 2.3, cavitation volume ratio of the movable core chamber has been shown to remain the bottom.

(Communication hole length and cavitation volume ratio)
Next, the relationship between the length of the communication hole 4 and the cavitation volume ratio will be described.
FIG. 15 is a graph with the communication hole length ratio as the horizontal axis and the cavitation volume ratio of the movable core chamber as the vertical axis. The communication hole length ratio refers to the ratio of the length of the communication hole 4 to the length of the core flow path 3.
In FIG. 15, the solid line X indicates the cavitation volume ratio of the gap between the inner wall of the movable core chamber and the movable core.
A solid line Y indicates the cavitation volume ratio of the breathing hole of the movable core.
A solid line Z indicates an average of the solid line X and the solid line Y.
The graph of FIG. 14 shows that the cavitation volume ratio of the movable core chamber changes from the bottom when the communication hole length ratio is 0.8 to 1.2.

(Effect of this embodiment)
In the present embodiment, the following effects are obtained.
(1) In this embodiment, the communication hole cross-sectional area ratio is 1.0 to 2.3.
When the communication hole cross-sectional area ratio is 1.0, the speed at which the fuel mass β excited in the core flow path 3 and the communication hole 4 flows into the fluid chamber is less than the case where the communication hole cross-sectional area ratio is less than 1.0. And the amplitude D of the generated negative pressure generated at the opening end of the communication hole 4 on the fluid chamber side becomes small. Therefore, the volume ratio of cavitation in the movable core chamber 16 can be reduced, and erosion of the movable core 14 and the inner wall of the movable core chamber 16 can be suppressed.
When the communication hole cross-sectional area ratio is greater than 1.0 and equal to or less than 2.3, the excitation force E generated from the gap is communicated with the generated negative pressure F reflected at the open end of the core flow path 3 on the communication hole side. The generated negative pressure G is reflected at the opening end of the hole 4 on the fluid chamber side. Since the two generated negative pressures F and G have a phase difference, the amplitude b of the combined negative pressure wave H obtained by combining the two generated negative pressures F and G is smaller than the amplitude of the excitation force E. It becomes. Therefore, the volume ratio of cavitation in the movable core chamber 16 can be reduced, and erosion of the movable core 14 and the inner wall of the movable core chamber 16 can be suppressed.

(2) In this embodiment, the communication hole length ratio is 0.8 to 1.2.
If the communication hole length ratio is less than 0.8 times, the length of the communication hole 4 is shortened, so that the amount of fuel mass ζ and η to be vibrated becomes small. Therefore, the speed at which the fuel mass ζ, η flows out into the fluid chamber is increased, and the generated negative pressures L, M generated at the opening end of the core channel 3 on the communication hole side and the opening end of the communication hole 4 on the fluid chamber side. The amplitude of becomes larger. Further, since the phase difference between the two generated negative pressures L and M is small, the amplitude d of the combined negative pressure wave N obtained by combining the two generated negative pressures L and M is large.
Further, if the communication hole length ratio is larger than 1.2 times, the fuel mass to be vibrated is only the fuel mass θ of the core flow path 3. Therefore, the speed at which the fuel mass θ flows out to the communication hole 4 is increased, and the amplitude e of the generated negative pressure P is substantially the same as the amplitude of the vibration force O.
Therefore, in this embodiment, by setting the communication hole length ratio to 0.8 to 1.2, the volume ratio of cavitation in the movable core chamber 16 is reduced, and the erosion of the inner walls of the movable core 14 and the movable core chamber 16 is reduced. Can be suppressed.

(Second Embodiment)
A second embodiment of the present invention is shown in FIG. In the second embodiment, components substantially the same as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
In the second embodiment, the flange 110 that covers the opening of the recess 28 of the pump body 20 and the partition 170 that separates the movable core chamber 16 and the fluid chamber 44 are configured separately.
Further, one end of the second spring 56 is locked to a spring locking portion 121 extending radially outward from the drive shaft 12, and the other end is locked to the partition portion 170. The second spring 56 biases the drive shaft 12 and the movable core 14 toward the pump chamber with a stronger force than the first spring 45.
Also in the second embodiment, the cross-sectional area of the communication hole 4 is 1.0 to 2.3 times the cross-sectional area of the core channel. The length of the communication hole 4 is 0.8 to 1.2 times that of the core channel.
The second embodiment has the same effects as the first embodiment.

(Other embodiments)
In the embodiment described above, the electromagnetic driving device 10 used in the high-pressure pump 1 has been described. On the other hand, in other embodiments, the electromagnetic drive device can be used for various devices having a function of opening and closing a fluid chamber.
In the embodiment described above, the electromagnetic drive device 10 has been described as a normally open valve in which the movable core 14 opens the suction valve 43 when the coil 15 is not energized. On the other hand, in other embodiments, the electromagnetic drive device may be a normally closed valve in which the movable core closes the suction valve when the coil is not energized.
In the embodiment described above, the suction valve 43 and the drive shaft 12 are configured separately. On the other hand, in another embodiment, the suction valve and the drive shaft may be configured integrally.
The present invention is not limited to the above embodiment, and can be implemented in various forms without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 3 ... Core flow path 4 ... Communication hole 10 ... Electromagnetic drive device 11, 110 ... Flange (housing)
16 ... movable core chambers 17, 170 ... partition 20 ... pump body (housing)
44 ... Fluid chamber 50 ... Breathing hole (core flow path)
51 ... Gap (core flow path)

Claims (5)

A fixed core (13);
A movable core (14) provided to be reciprocally movable with respect to the fixed core;
A coil (15) for generating a magnetic attractive force between the fixed core and the movable core by energization;
Biasing means (56) for biasing the movable core in a direction away from the fixed core;
A housing (11, 20, 110) having a movable core chamber (16) for accommodating the movable core, and a fluid chamber (44) through which a fluid flows;
A partition (17, 170) having a communication hole (4) for separating the movable core chamber and the fluid chamber and communicating the movable core chamber and the fluid chamber;
A drive shaft (12) having one end fixed to the movable core, the other end extending to the fluid chamber, and supported by the partition portion so as to be reciprocally movable;
The cross-sectional area of the communication hole having a partition unit state, and are more cross-sectional area of the core flow path provided in the moving direction of the movable core in the movable core chamber (3,50,51),
The electromagnetic drive device (10) , wherein a cross-sectional area of the communication hole of the partition portion is 1.0 to 2.3 times a cross-sectional area of the core flow path . The length of the communication hole having a partition section is an electromagnetic driving device according to claim 1, wherein the core flow channel is a length of 0.8 times or more. The electromagnetic drive device according to claim 2 , wherein a length of the communication hole of the partition portion is 0.8 to 1.2 times a length of the core flow path. The fuel sucked into the pump chamber (27) from the fuel inlet through the fluid chamber is pressurized by the reciprocating movement of the plunger (21), and the fuel pressurized in the pump chamber is discharged from the fuel discharge port (66). In the high pressure pump (1),
The high pressure pump provided with the electromagnetic drive device as described in any one of Claims 1-3 which controls operation | movement of the suction valve (43) which connects the said pump chamber and the said fluid chamber, and cuts off with the said drive shaft. The partition portion of the electromagnetic drive apparatus, in claim 4, wherein a flange for mounting the electromagnetic drive device to the pump body constituting the fluid chamber of the high pressure pump (20) (11) The high-pressure pump described.

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