JP4483829B2 - Electromagnetic actuator - Google Patents

Description

  The present invention relates to an electromagnetic actuator having a clearance (side gap) in a radial direction of an armature.

(Conventional technology)
An example of an electromagnetic actuator having a clearance in the radial direction of the armature will be described with reference to FIG. The electromagnetic actuator shown in FIG. 1A is mounted on a pressure reducing valve 11 that reduces and adjusts the actual rail pressure of the common rail of the common rail fuel injection device.
The electromagnetic actuator 42 of the pressure reducing valve 11 applies an axial displacement force to the push rod 26 supported so as to be slidable in the axial direction, and is fixed to the push rod 26 and a coil 46 that generates a magnetic force when energized. Then, an armature 44 made of a magnetic member that is supported integrally with the push rod 26 so as to be displaceable in the axial direction, a magnetic attracting portion 47 that magnetically attracts the armature 44 in the axial direction by the magnetic force generated by the coil 46, And a magnetic delivery part 48 that is disposed between the armatures 44 via the clearance A and delivers the magnetic force generated by the coil 46 from the radial direction to the armatures 44 (for example, Patent Document 1).

(Problems of conventional technology)
When the armature 44 is displaced in the axial direction, the volume of the chamber on the side of the magnetic attraction portion 47 of the armature 44 (in this example, the spring chamber 43 in which the spring means 41 for biasing the armature 44 in the valve closing direction) is changed. . The spring chamber 43 breathes (changes in volume) through the clearance A. When fluid (fuel) flows through the clearance A, the volume of the spring chamber 43 changes and the armature 44 is displaced in the axial direction. .

Since the clearance A is a portion where the magnetic force generated by the coil 46 is transferred in the radial direction, when the clearance A increases, the magnetic force applied to the armature 44 decreases and the magnetic attractive force of the armature 44 decreases. For this reason, the clearance A cannot be increased.
As described above, since the clearance A cannot be increased, the fuel passage area by the clearance A is small and the flow resistance is large. As a result, breathing of the spring chamber 43 is hindered, and the responsiveness (movability) of the armature 44 and the push rod 26 is inhibited.
Further, since the fluid (fuel) flows through the narrow clearance A, the flow velocity of the fluid flowing through the clearance A is high, and the end surface of the armature 44 may be damaged by erosion.

In the above description, the background art of the invention has been described by taking the electromagnetic actuator 42 applied to the pressure reducing valve 11 as an example. However, the same problem occurs even with other electromagnetic actuators having a clearance in the radial direction of the armature.
Japanese Patent Laid-Open No. 2001-182638

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electromagnetic actuator capable of further improving the responsiveness of the armature without causing a decrease in the magnetic attractive force of the armature.

[Means of claim 1]
In the electromagnetic actuator employing the means of claim 1, the movable part including the armature (hereinafter referred to as the movable part) is provided with a breathing passage from the end surface on the magnetic attraction part side.
This breathing passage allows breathing between the armature's magnetic suction portion side and a different side of the armature's magnetic suction portion, so that the flow resistance of the fluid flowing for breathing can be reduced while keeping the clearance narrow. Thereby, the volume fluctuation in the room partitioned by the armature becomes easy, and the responsiveness of the movable part can be improved.
Further, since the passage area of the fluid flowing for respiration increases, the flow velocity of the fluid becomes slow, and the occurrence of erosion on the end face of the armature can be suppressed.
Further, the stopper that abuts the end surface of the movable portion on the magnetic attracting portion side and restricts the axial displacement of the movable portion toward the attracting side is provided with a groove on the abutting surface so as not to block the breathing passage. The breathing passage can continue the breathing action by this groove.

[Means of claim 2]
The breathing passage in the electromagnetic actuator employing the means of claim 2 is formed so as to penetrate in the axial direction in the movable portion .

[Means of claim 3]
The breathing passage in the electromagnetic actuator employing the means of claim 3 is formed in a shaft that is fixed through the center of the movable portion in the axial direction .

[Means of claim 4]
The stopper in the electromagnetic actuator adopting the means of claim 4 is in contact with the end face of the shaft to limit the axial displacement of the movable part toward the suction side.

[Means of claim 5]
Groove of the stopper in an electromagnetic actuator to adopt means of claim 5 is shall be open breathing passages in the radial direction.

[Means of claim 6]
The groove of the stopper in the electromagnetic actuator employing the means of claim 6 forms a cross groove.

[Means of Claim 7]
The electromagnetic actuator adopting the means of claim 7 drives a valve body that opens and closes the flow path or adjusts the flow rate of the fluid passing through the flow path in the axial direction.
That is, it is applied to the electromagnetic actuator of the valve device, and the responsiveness of the valve body can be improved. Further, in the valve device, it is possible to suppress the occurrence of erosion on the end face of the armature, and to improve the reliability of the valve device.

[Means of Claim 8]
The electromagnetic actuator adopting the means of claim 8 is a pressure reducing valve driving means capable of adjusting the actual rail pressure of the common rail storing high pressure fuel in the common rail type fuel injection device.
Thus, by applying to a pressure reducing valve, the responsiveness of the pressure reducing valve can be improved, and the actual rail pressure can be quickly reduced. Further, in the pressure reducing valve, the occurrence of erosion on the end face of the armature can be suppressed, and the reliability of the pressure reducing valve can be improved.

The electromagnetic actuator of the best mode 1 includes a coil that generates a magnetic force when energized, an armature made of a magnetic member that is supported so as to be displaceable in the axial direction, and a movable part including the armature is magnetized in the axial direction by the generated magnetic force. Magnetic attraction part to be attracted, magnetic outer part that covers the outer periphery of the armature and is arranged with clearance between the armature and delivers the magnetic force generated by the coil from the radial direction to the armature, and the magnetic attraction part side of the movable part And a stopper that limits axial displacement of the movable part toward the suction side .
The movable part including the armature is provided with a breathing passage from the end face on the magnetic attraction part side . Further, a groove for preventing the breathing passage from being closed is provided on the contact surface of the stopper with the movable portion.

[Reference Example 1]
Reference Example 1 in which an electromagnetic actuator is applied to a pressure reducing valve will be described with reference to the drawings. In this reference example 1, first, in schematic configuration of a common rail type fuel injection system in the "basic structure of a common rail fuel injection apparatus", and describes a pressure reducing valve of conventional structure, then "Reference Example 1, wherein" the A pressure reducing valve to which a reference example is applied will be described.

[Basic configuration of common rail fuel injection system]
The common rail fuel injection device will be described with reference to FIG.
The common rail fuel injection device shown in FIG. 2 is an injection system that injects fuel into a four-cylinder engine (for example, a diesel engine: not shown), and includes a common rail 1, an injector 2, a supply pump 3, a control device 4, and the like. ing. The control device 4 includes an ECU (engine control unit) 4a and an EDU (drive unit) 4b. FIG. 2 shows an example in which the ECU 4a and the EDU 4b are separately mounted. The EDU 4b may be arranged.

  The common rail 1 is a pressure accumulating container for accumulating high pressure fuel supplied to the injector 2, and the high pressure fuel is supplied via a pump pipe (high pressure fuel flow path) 6 so that rail pressure corresponding to fuel injection pressure is continuously accumulated. And a plurality of injector pipes 7 for supplying high-pressure fuel to each injector 2.

A pressure reducing valve 11 (an example of a valve device) is attached to a relief pipe 9 that returns fuel from the common rail 1 to the fuel tank 8. The pressure reducing valve 11 opens when the actual rail pressure PCi in the common rail 1 is higher than the target rail pressure PC0 calculated by the ECU 4a, and quickly reduces the actual rail pressure PCi to the target rail pressure PC0.
Details of the pressure reducing valve 11 will be described later.

The supply pump 3 is a fuel pump that pumps high-pressure fuel to the common rail 1, and feeds the fuel in the fuel tank 8 through the fuel filter 8a, and compresses the fuel sucked up by the feed pump to a high pressure. And a high-pressure pump that feeds pressure to the common rail 1. The feed pump and the high-pressure pump are driven by a common camshaft. The camshaft is rotationally driven by the engine.
The supply pump 3 is equipped with an SCV (suction metering valve) 12 that adjusts the amount of fuel sucked into the high-pressure pump, and the SCV 12 is adjusted by the control device 4 so that the common rail 1 The actual rail pressure PCi to be accumulated is adjusted.

The ECU 4a includes functions such as a CPU for performing control processing and arithmetic processing, a storage device for storing various programs and data (memory such as ROM, SRAM or EEPROM, RAM), an input circuit, an output circuit, a power supply circuit, and the like. A microcomputer having a known structure is provided. Various arithmetic processes are performed based on sensors signals (engine parameters: signals corresponding to the operating state of the occupant, the operating state of the engine, etc.) read into the ECU 4a.
The sensors connected to the ECU 4a include, in addition to the rail pressure sensor 13 that detects the actual rail pressure PCi accumulated in the common rail 1 as the detected rail pressure PCk, an accelerator sensor that detects the accelerator opening, and the engine speed. There are a rotation speed sensor that detects the temperature of the engine, a water temperature sensor that detects the coolant temperature of the engine, a fuel temperature sensor that detects the temperature of the fuel supplied to the injector 2, and other sensors.

(Injector control system)
The ECU 4a determines an injection mode as a control program for the injector 2 based on a program stored in the ROM and a sensor signal (vehicle driving state) read into the RAM for each fuel injection. Injection mode determining means ”,“ target injection amount calculating means ”for calculating a target injection amount for each injection, and“ target injection timing calculating means ”for calculating an injection start timing for each injection.
The “injection mode determination means” is a control program that determines the injection mode (single injection, multi-injection, etc.) of the injector 2 according to the current operating state.
The “target injection amount calculation means” is a control program for determining a target injection amount corresponding to the current operation state and determining a command injector driving time for obtaining this target injection amount.
The “target injection timing calculation means” is a control program that calculates a target injection timing according to the current operation state and calculates an injection command timing for starting injection at the target injection timing.

(Rail pressure control system)
The ECU 4a sets the target rail pressure PC0 as a control program for the actual rail pressure PCi accumulated in the common rail 1, based on a program stored in the ROM and sensor signals (vehicle driving state) read into the RAM. “Target rail pressure calculating means” to be calculated, “SCV control means” for controlling the energization amount of the SCV 12 based on the calculated target rail pressure PC0, and “Energizing amount of the pressure reducing valve 11 to be calculated based on the target rail pressure PC0” Pressure reducing valve control means ”.
The “target rail pressure calculating means” is a program for obtaining the target rail pressure PC0 using a map or a calculation formula according to the current operation state.
The “SCV control means” calculates the energization amount given to the SCV 12, calculates the SCV opening at which the detected rail pressure PCk read by the rail pressure sensor 13 becomes the target rail pressure PC0, and the SCV opening is SCV12. As shown in FIG. 4, the control program causes the SCV drive circuit to generate a valve opening signal (for example, a PWM signal).

  The “pressure reducing valve control means” includes “open valve pressure open control” for calculating an energization amount applied to the pressure reducing valve 11 by open control, and “flow rate feedback control” for calculating an energization amount applied to the pressure reducing valve 11 by feedback control. There is.

“Valve open pressure open control” controls the valve opening pressure at which the pressure reducing valve 11 switches from the closed state to the valve opened state by controlling the closing force of the pressure reducing valve 11. Control for calculating an energization amount to be the target rail pressure PC0 and generating a valve opening pressure setting signal (for example, PWM signal) in the pressure reducing valve drive circuit provided in the EDU 4b so that the amount of energization is given to the pressure reducing valve 11 It is a program.
On the other hand, the “flow rate feedback control” calculates a pressure reducing valve opening degree at which the detected rail pressure PCk read by the rail pressure sensor 13 becomes the target rail pressure PC0, and the pressure reducing valve opening degree represents an energization amount obtained by the pressure reducing valve 11. This is a control program for generating a valve opening pressure setting signal (for example, a PWM signal) in a pressure reducing valve driving circuit provided in the EDU 4b so that the calculated amount of current is supplied to the pressure reducing valve 11.
Either “open valve pressure open control” or “flow rate feedback control” may be used.

(Description of pressure reducing valve 11)
Next, a pressure reducing valve 11 having a conventional structure will be described with reference to FIG. In the following description, the lower side (valve closing direction) in FIG. 1 will be referred to as the lower side, and the upper side (valve opening direction) in FIG. 1 will be referred to as the upper side. This is not related to the assembly direction.
The pressure reducing valve 11 is integrally provided with an opening / closing valve 21 and a driving means 22 for driving the opening / closing valve 21. The opening / closing valve 21 includes a fastening cylinder 23, a bush valve 24, a body valve 25, a push rod. 26.

The fastening cylinder 23 has a cylindrical shape formed concentrically with the yoke 50 on the lower surface of a yoke 50 (to be described later), and an external thread that engages with an internal thread formed on the common rail 1 on the outer peripheral surface thereof. 27 is formed. The upper part of the bush valve 24 is fitted inside the fastening cylinder 23 so that the bush valve 24 is centered on the fastening cylinder 23, and the bush valve 24 is secured by caulking the lower end of the fastening cylinder 23. Is fixed in the fastening cylinder 23.
The ring plate disposed between the bush valve 24 and the yoke 50 (described later) in the axial direction is a stopper 31, and when the push rod 26 is lifted upward, it is in the middle of the push rod 26. It abuts against the formed step and regulates the lift amount of the push rod 26 to prevent the armature 44 (described later) from contacting the magnetic attracting portion 47 (described later).

  The bush valve 24 is inserted into the common rail 1, has a bottomed cylindrical shape, and is fixed to the fastening cylinder 23 as described above. At the center of the bottom of the bush valve 24, a high-pressure fuel inlet 32 communicating with the common rail 1 is formed. In addition, a first radial hole 33 is formed in the cylindrical portion of the bush valve 24 so as to penetrate the inside and outside and communicate with the low pressure fuel passage (passage communicating with the relief pipe 9) on the outer peripheral side.

The body valve 25 is inserted into the bush valve 24 and is centered, and has a bottomed cylindrical shape. The body valve 25 is urged downward by a seating spring 34 arranged in a compressed state between the stopper 31 and the body valve 25 in the axial direction, so that the lower surface of the bottom portion of the body valve 25 is the bottom portion of the bush valve 24. A valve port (an example of a channel to be opened and closed) 35 formed in the center of the bottom of the body valve 25 communicates with the inside of the common rail 1 via the introduction port 32. .
A slide hole 36 is formed in the shaft center of the body valve 25 to support the push rod 26 slidably in the axial direction. Further, a second radial hole 37 is formed at the lower end of the cylindrical portion of the body valve 25 so as to penetrate the inside and outside and communicate with the first radial hole 33 on the outer peripheral side. The second radial hole 37 is led to the relief pipe 9 through the first radial hole 33.

The push rod 26 is a cylindrical rod-shaped shaft that is slidably supported in the axial direction by a sliding hole 36 formed at the center of the body valve 25, and a conical valve body is provided at the lower end of the push rod 26. 38 is formed. The valve body 38 closes the valve opening 35 by sitting on a valve seat 39 around the valve opening 35. Further, the valve body 38 receives a force (valve opening force) in a direction away from the valve seat 39 by the high-pressure fuel in the valve port 35, and the valve body 38 is separated from the valve seat 39. The high-pressure fuel in the common rail 1 is guided to the relief pipe 9 through the valve port 35 → the lower portion of the sliding hole 36 → the second radial hole 37 → the first radial hole 33.
In this example, the valve body 38 is formed directly at the tip of the push rod 26, but a valve body (ball or the like) provided separately from the push rod 26 is attached to the tip of the push rod 26. The valve body (ball or the like) may be seated or separated from the valve seat 39.
Further, an armature 44 described later is fixed to the upper portion of the push rod 26.

The driving means 22 applies axial displacement force (valve closing force and valve opening force) to the push rod 26, and includes a spring means 41 and an electromagnetic actuator 42.
The spring means 41 is a compression coil spring that urges the upper end of the push rod 26 downward and applies an urging force in the valve closing direction to the push rod 26, and is placed in a spring chamber 43 formed on the upper portion of the push rod 26. Arranged in a compressed state.

The electromagnetic actuator 42 includes an armature 44 and a solenoid (electromagnet) 45 that magnetically attracts the armature 44.
The armature 44 is a magnetic member having a substantially disk shape (for example, a ferromagnetic material such as iron), and is fixed to an upper portion of the push rod 26 that is slidably supported in the axial direction, and is integrated with the push rod 26. Move up and down.

The solenoid 45 varies the axial displacement force applied to the push rod 26 by magnetically attracting the armature 44 in the axial direction. Specifically, the solenoid 45 shown in FIG. 1 magnetically attracts the armature 44 in the valve opening direction in accordance with the energization amount, and includes a coil 46 that generates a magnetic force by energization and a closed magnetic path that passes through the armature 44. A magnetic path forming member to be formed.
The coil 46 is obtained by winding a large number of conductive wires with insulation coating around the resin bobbin, and is electrically connected to the EDU 4b (specifically, a pressure reducing valve driving circuit) via a connector and a connection line (not shown). Is generated, and a magnetic force is generated in accordance with the energization amount (calculated value of the ECU 4a) given from the EDU 4b.

The magnetic path forming member covers the outer periphery of the armature 44 and the magnetic attraction portion 47 that magnetically attracts the armature 44 in the axial direction (the valve opening direction in this embodiment) by the magnetic force generated by the coil 46. And a magnetic delivery part 48 that delivers the magnetic force generated by the coil 46 to the armature 44 from the radial direction.
Specifically, the magnetic path forming member includes a stator 49 and a yoke 50.

  The stator 49 is formed of a magnetic member (for example, a ferromagnetic material such as iron). The stator 49 is fixed to the upper portion of the yoke 50 by caulking, and the rod-shaped portion 49 b is inserted into the coil 46. Is provided. And the magnetic attraction | suction part 47 is formed in the lower end (part which opposes the armature 44 in an axial direction) of the rod-shaped part 49b (stator 49). The above-described spring chamber 43 is formed in the central portion below the rod-shaped portion 49b (stator 49).

The yoke 50 has a substantially cylindrical shape formed of a magnetic member (for example, a ferromagnetic material such as iron), and includes a coil housing portion 50 a that covers the outer periphery of the coil 46 and an armature housing portion that covers the outer periphery of the armature 44. 50b. And the magnetic delivery part 48 is formed in the innermost periphery (part which opposes the armature 44 in radial direction) of the armature accommodating part 50b.
When the coil 46 is energized to generate a magnetic force, a closed magnetic path passing through the yoke 50 → the armature 44 → the stator 49 is formed, and a magnetic attractive force corresponding to the magnetic force generated by the coil 46 is applied to the armature 44 and the magnetic attractive portion 47. Occurs in the interval (magnetic attraction gap B), and a displacement force in the valve opening direction is applied to the armature 44.

As described above, when the coil 46 is energized, the electromagnetic actuator 42 magnetically attracts the armature 44 in the valve opening direction by the magnetic force generated by the coil 46. As the energization amount applied to the coil 46 increases, The urging force in the valve closing direction applied to the push rod 26 is reduced.
That is, in the pressure reducing valve 11 shown in FIG. 1, when the energization amount given to the solenoid 45 is small, the urging force in the valve closing direction is strengthened and the valve opening pressure of the pressure reducing valve 11 is set high. When the amount is large, the urging force in the valve closing direction is weakened and the valve opening pressure is set low.
In contrast to the pressure reducing valve 11 shown in FIG. 1, the pressure reducing valve 11 may be a type in which the urging force in the valve closing direction increases as the energization amount applied to the solenoid 45 increases.

(Basic operation of the pressure reducing valve 11)
Next, an operation example when the pressure reducing valve 11 is controlled by the valve opening pressure open control will be described.
When the actual rail pressure PCi in the common rail 1 rises above the valve opening pressure (target rail pressure PC0) of the pressure reducing valve 11 set by the ECU 4a, the valve closing force (from the spring means 41) that causes the drive means 22 to seat the valve body 38. The valve opening force received by the valve body 38 via the valve port 35 is superior to the axial force obtained by subtracting the magnetic attractive force of the electromagnetic actuator 42, and the valve body 38 is separated from the valve seat 39. Then, the fuel in the common rail 1 passes through the relief pipe 9 via the valve port 35 → the lower part of the sliding hole 36 → the first radial hole 33 → the second radial hole 37 and is returned into the fuel tank 8. In this way, the actual rail pressure PCi is lowered by discharging the fuel in the common rail 1 through the pressure reducing valve 11.
When the actual rail pressure PCi in the common rail 1 decreases to the valve opening pressure of the pressure reducing valve 11 (target rail pressure PC0), the valve closing force by which the driving means 22 seats the valve body 38 is controlled via the valve port 35. The valve body 38 is seated on the valve seat 39, exceeding the valve opening force received by the body 38. As a result, the actual rail pressure PCi is maintained at the valve opening pressure of the pressure reducing valve 11 (target rail pressure PC0).

(When target rail pressure PC0 increases)
When the target rail pressure PC0 increases, the energization amount of the pressure reducing valve 11 is reduced by the open control, and the valve closing force of the pressure reducing valve 11 is increased, so that the valve opening pressure of the pressure reducing valve 11 increases to the target rail pressure PC0. Be changed. At this time, as the target rail pressure PC0 increases, the opening degree of the SCV 12 is largely controlled, and the discharge amount of the supply pump (high pressure pump) 3 is also increased.

(When target rail pressure PC0 decreases)
When the target rail pressure PC0 decreases, the energization amount of the pressure reducing valve 11 is increased by the open control, and the valve closing force of the pressure reducing valve 11 is reduced, so that the valve opening pressure of the pressure reducing valve 11 is reduced to the target rail pressure PC0. Be changed. At this time, as the target rail pressure PC0 is lowered, the opening of the SCV 12 is controlled to be small, and the discharge amount of the supply pump (high pressure pump) 3 is also reduced.
Immediately after the target rail pressure PC0 is lowered, the actual rail pressure PCi is higher than the valve opening pressure (target rail pressure PC0). Therefore, the pressure reducing valve 11 immediately self-opens to quickly increase the pressure in the common rail 1 to the target rail pressure PC0. Lower.
When the actual rail pressure PCi drops to the target rail pressure PC0, the pressure reducing valve 11 immediately closes itself.

[Features of Reference Example 1 ]
The characteristics of the reference example 1, first described the "background of Reference Example 1", describing the "resolution technique of Reference Example 1" thereafter.
(Background of Reference Example 1 )
When the armature 44 is displaced in the axial direction, the volume of the spring chamber 43 on the upper side of the armature 44 (on the magnetic attraction portion 47 side) changes. The spring chamber 43 breathes (changes in volume) through the clearance A. When fuel flows through the clearance A, the volume of the spring chamber 43 changes and the armature 44 is displaced in the axial direction.
The space below the armature 44 (the side different from the magnetic attraction portion 47) is a gap between the body valve 25 and the push rod 26 (hereinafter referred to as a sliding clearance C), and a gap between the bush valve 24 and the body valve 25. (Hereinafter referred to as assembly clearance D) communicates with the low pressure side (between the lower end of the sliding hole 36 and the first radial hole 33 and the second radial hole 37). It is led to the space below.

The clearance A is a part where the magnetic force generated by the coil 46 is transferred in the radial direction. For this reason, when the clearance A increases, the magnetic force applied to the armature 44 decreases, and the magnetic attractive force (force in the valve opening direction) of the armature 44 decreases. For this reason, the clearance A cannot be increased.
As described above, since the clearance A cannot be increased, the flow path area of the fuel due to the clearance A is small, and the flow resistance of the fuel flowing through the clearance A is large. As a result, the breathing of the spring chamber 43 is hindered, and the responsiveness of the armature 44 and the push rod 26 is inhibited.
Further, since the fuel flows through the narrow clearance A when the armature 44 moves, the flow rate of the fuel flowing through the clearance A is high, and the end surface of the armature 44 may be damaged by erosion.

(Solution technology of Reference Example 1 )
A technique for solving the above problem will be described with reference to FIG. In the following, only the difference in solving the problem in the pressure reducing valve 11 will be described, and the other parts have the same structure as the pressure reducing valve 11 of the conventional structure described above.
The pressure reducing valve 11 having the conventional structure is configured such that the spring chamber 43 is respired only by the fuel passing through the clearance A.
On the other hand, the pressure reducing valve 11 of the reference example 1 has a breathing passage from an end surface on the upper side of the armature 44 (on the magnetic suction portion 47 side) to a movable portion including the armature 44 (in this reference example , the armature 44 and the push rod 26). 51 is provided. That is, the breathing passage 51 is a fuel passage that extends from the upper end surface (upper surface) of the armature 44 to the lower side of the armature 44 (a side different from the magnetic attraction portion 47).

The breathing passage 51 of Reference Example 1 is formed in the push rod 26 (an example of a shaft fixed through the center of the armature 44 in the axial direction), and is in the middle of the axial direction from the upper end of the push rod 26 ( A central hole 51a opened to the lower side of the armature 44 and a radial hole 51b opened radially in the push rod 26 on the lower side of the armature 44. The central hole 51a communicates with the radial hole 51b for breathing. A passage 51 is formed.

In this way, the breathing passage 51 that communicates the upper side and the lower side of the armature 44 is formed in the push rod 26, and the breathing in the spring chamber 43 (the chamber on the magnetic attraction portion 47 side of the armature 44) is breathed through the breathing passage 51. It is done. Even if the passage area of the respiratory passage 51 is increased, the clearance A can be kept narrow. That is, the passage area of the respiratory passage 51 can be increased while the clearance A is kept narrow.
For this reason, the flow resistance of the fuel flowing for the breathing of the spring chamber 43 can be reduced, and the volume fluctuation of the spring chamber 43 is facilitated, so that the responsiveness of the mover (armature 44 and push rod 26) can be improved. it can. As a result, the responsiveness of the pressure reducing valve 11 can be improved, and when the actual rail pressure PCi is higher than the target rail pressure PC0, the actual rail pressure PCi can be quickly reduced to the target rail pressure PC0.

Further, by providing the breathing passage 51, the flow rate of the fuel flowing for breathing in the spring chamber 43 becomes slow, and the occurrence of erosion of the end face of the armature 44 can be suppressed. Thereby, the long-term reliability of the pressure reducing valve 11 can be improved.
Furthermore, since it is only necessary to provide the breathing passage 51 in the push rod 26 of the pressure reducing valve 11 having the conventional structure, an increase in cost of the pressure reducing valve 11 can be suppressed.

Next, examples of the present invention will be described. A pressure reducing valve 11 as an application example of the electromagnetic actuator 42 will be described with reference to FIG. In the following examples, the same reference numerals as those in Reference Example 1 indicate the same functions.
The pressure reducing valve 11 includes a fastening cylinder 23, a rod guide 52, a push rod 26, a ball 53, a seat member 54, and a driving unit 22.
The fastening cylinder 23 is fastened to the end of the common rail 1, and a guide insertion hole 55 that accommodates the rod guide 52 and the armature 44 is formed in the axial direction in the center.

A large-diameter hole 56 into which the lower end of a rod guide 52 (a centering outer cylinder 58 to be described later) and a sheet member 54 are fitted is formed in the distal end of the fastening cylinder 23 in the axial direction. The large-diameter hole 56 is a cylindrical hole concentric with the fastening cylinder 23, and the lower end of the rod guide 52 and the sheet member 54 are fitted therein, and the fastening cylinder 23, the rod guide 52, and the sheet member 54 are inserted. These three centerings are made. The rod guide 52 and the sheet member 54 are fixed to the fastening cylinder 23 by caulking the tip of the fastening cylinder 23.
On the upper side of the fastening cylinder 23 (on the side close to the yoke 50), a male screw 27 that is screwed into the female screw formed on the common rail 1 is formed.

The rod guide 52 is assembled into the guide insertion hole 55 from the lower end of the fastening cylinder 23 and has a cylindrical shape in which a slide hole 36 is formed to support the push rod 26 so as to be slidable in the axial direction.
The outer diameter of the rod guide 52 inserted into the inner periphery of the guide insertion hole 55 is smaller than the inner diameter of the guide insertion hole 55, and the inner peripheral surface of the guide insertion hole 55 and the outer peripheral surface of the rod guide 52. An assembly clearance D is formed between the two.

  A cylindrical centering outer cylinder 58 is formed on the outer periphery of the lower end of the rod guide 52 so as to be inserted into the large-diameter hole 56 and whose outer diameter matches the inner diameter of the large-diameter hole 56. The axis of the centering outer cylinder 58 coincides with the axis of the rod guide 52. Then, the centering outer cylinder 58 is incorporated into the inner peripheral surface of the large-diameter hole 56, whereby the rod guide 52 is centered on the fastening cylinder 23.

  On the inner periphery of the lower end of the rod guide 52, an inner hole 59 larger in diameter than the sliding hole 36 is formed in the axial direction. The inner hole 59 is a cylindrical hole concentric with the rod guide 52, and the fuel that has passed through the valve port 35 formed in the seat member 54 flows into the inner hole 59. The second radial hole 37 formed radially from the inner hole 59 is connected to the relief pipe 9 via the first radial hole 33 formed in the fastening cylinder 23 via the assembly clearance D. Communicate with the aisle.

  The push rod 26 is a cylindrical rod-shaped shaft that is slidably supported in the axial direction by a sliding hole 36 formed in the central portion of the rod guide 52, and the axial displacement force by the driving means 22 is applied to the ball 53. It is a transmission member to convey.

  The ball 53 is pressed downward by a flat portion (ball pressing surface) formed at the tip of the push rod 26 and is seated on the valve seat 39 of the seat member 54. In this example, an example is shown in which a ball 53 (an example of a valve body) disposed at the tip of the push rod 26 is seated or separated from the valve seat 39, but the ball 53 is abolished and the tip of the push rod 26 is removed. The valve body may be formed directly on the part, and the push rod 26 may be directly seated on or separated from the valve seat 39.

The seat member 54 has a substantially disk shape, and has a valve portion 35 (for example, an orifice forming a high-pressure fuel passage) that communicates with the inside of the common rail 1 and guides the high-pressure fuel in the common rail 1 to the inside of the inner hole 59. ) Is formed.
On the upper side of the seat member 54, a tapered valve seat 39 that closes the valve opening 35 by the ball 53 seating is formed around the valve opening 35. When the ball 53 is separated from the valve seat 39, the valve port 35 is opened, and the high-pressure fuel in the common rail 1 causes the valve port 35 → the inner hole 59 → the second radial hole 37 → the first radial hole. It is led to the relief pipe 9 through 33.

  The outer diameter of the sheet member 54 matches the inner diameter of the large-diameter hole 56 formed at the end of the fastening cylinder 23, and the outer-diameter portion of the sheet member 54 is formed on the inner peripheral surface of the large-diameter hole 56. It is inserted. Reference numeral 61 arranged between the sheet member 54 and the rod guide 52 in the axial direction is a shim packing having a ring disk shape, and is compressed in the axial direction of the sheet member 54 and the rod guide 52 so as to be compressed. The fuel is prevented from flowing into the inner hole 59 from the gap between the fastening cylinders 23.

Around the valve seat 39 in the seat member 54, a cylindrical centering inner cylinder 62 is formed which is inserted into the inner hole 59 and whose outer diameter matches the inner diameter of the inner hole 59. The axis of the centering inner cylinder 62 coincides with the axis of the valve seat 39. The valve seat 39 is centered on the rod guide 52 by incorporating the centering inner cylinder 62 into the inner peripheral surface of the inner hole 59.
That is, by incorporating the centering inner cylinder 62 of the seat member 54 into the inner peripheral surface of the inner hole 59 of the rod guide 52, the centering of the axis of the sliding hole 36 and the axis of the valve seat 39 is achieved.

Further, by incorporating the centering outer cylinder 58 of the rod guide 52 on which the seat member 54 is centered into the inner peripheral surface of the large-diameter hole 56 of the fastening cylinder 23, the axis of the sliding hole 36 and the axis of the valve seat 39 are obtained. And three centering of the axial center of the fastening cylinder 23 is comprised.
Then, after assembling the rod guide 52, the shim packing 61, and the sheet member 54 to the fastening cylinder 23, the lower end of the fastening cylinder 23 is crimped inward in the axial direction, whereby the rod guide 52, the shim packing 61, and the sheet member 54 are secured. Is fixed to the fastening cylinder 23.
The rod guide 52 is supported in the fastening cylinder 23 only by the centering outer cylinder 58 at the lower end, and the other part (the part inserted into the inner periphery of the guide insertion hole 55) has an assembly clearance D. It does not come into contact with the fastening cylinder 23 via. As a result, even if the fastening cylinder 23 is fastened to the common rail 1 and the fastening cylinder 23 is distorted, the distortion is blocked by the assembly clearance D, so that the sliding hole 36 is not distorted.

The driving means 22 applies axial displacement force (valve closing force and valve opening force) to the ball 53 via the push rod 26, and includes a spring means 41 and an electromagnetic actuator 42.
The spring means 41 is a compression coil spring that urges the armature 44 fixed to the upper portion of the push rod 26 downward and applies a biasing force in the valve closing direction to the ball 53 via the push rod 26. It arrange | positions in the state compressed in the spring chamber 43 formed in the upper part.
Inside the spring chamber 43, there is disposed a stopper 31 that restricts the lift amount of the armature 44 and prevents the armature 44 from coming into contact with the magnetic attraction portion 47 when the armature 44 is displaced upward. The spring means 41 is compressed between a spring seat formed on the top of the stopper 31 and the armature 44, and urges the armature 44 downward.

The electromagnetic actuator 42 is the same as that of the first embodiment, which includes an armature 44 and a solenoid 45 that magnetically attracts the armature 44. A magnetic attraction portion 47 is provided above the armature 44. A magnetic delivery part 48 is provided around the clearance A.
The push rod 26 of the embodiment is provided with a breathing passage 51 similar to that of the reference example 1 . For this reason, the effect similar to the reference example 1 can be acquired. That is, the responsiveness of the mover (the armature 44 and the push rod 26) can be improved, and the occurrence of erosion of the end face of the armature 44 can be suppressed.

Here, the pressure reducing valve 11 of this embodiment has a structure in which the upper end surface of the push rod 26 and the lower end surface of the stopper 31 are in contact with each other when the push rod 26 is lifted (valve open state). When the valve 11 is opened, the lower end surface of the stopper 31 may block the upper opening of the breathing passage 51 (opening in the spring chamber 43). When the breathing passage 51 is blocked by the stopper 31, the responsiveness of the movable part (the armature 44 and the push rod 26) is deteriorated, and the responsiveness of the pressure reducing valve 11 is deteriorated.
Therefore, in this embodiment , as shown in FIG. 3B, a groove (cross groove in this embodiment) 63 is formed in the lower end surface of the stopper 31 so that the breathing passage 51 is not blocked by the stopper 31. It has been. Thus, since the stopper 31 does not block the respiratory passage 51 by the groove 63 formed in the lower end surface of the stopper 31, the respiratory action by the respiratory passage 51 is always ensured. That is, since there is no hindrance to the responsiveness of the movable part (the armature 44 and the push rod 26), the responsiveness of the pressure reducing valve 11 does not deteriorate.
As described above, in a structure in which both end surfaces of the flat surfaces (the upper end surface of the push rod 26 and the lower end surface of the stopper 31) are in contact with each other, when the closely contacted planes are difficult to peel off (so-called linking) or conversely Although there is a possibility that phenomena that are difficult to approach due to the oil film force may occur, such a phenomenon can be prevented by the grooves 63.

[Reference Example 2]
Figure 4 Reference Example 2 will be described with reference to FIG.
In the reference example 1 and the example described above, an example in which the breathing passage 51 is formed in the push rod 26 of the movable portion is shown.
On the other hand, in Reference Example 2, the breathing passage 51 is formed in the armature 44 of the movable part .
The breathing passage 51 formed in the armature 44 is one or a plurality of through holes penetrating in the axial direction in the armature 44, and from the end surface (upper surface) on the upper side (on the magnetic attraction portion 47 side) of the armature 44. This is a fuel passage that communicates with an end surface (lower surface) on the lower side (a side different from the magnetic attraction portion 47). The breathing passage 51 formed in the armature 44 is provided at a position (for example, the center side) where the magnetic flux density passing through the armature 44 is not reduced as much as possible.
As described above, even if the breathing passage 51 is provided in the armature 44, the spring chamber 43 can be easily breathed, so that the same effect as in the reference example 1 can be obtained.

Next, the specific configuration of the respiratory passage 51 provided in the armature 44 is as follows.
φD1: a diameter of a virtual circle connecting the central axes of the plurality of respiratory passages 51 (hereinafter referred to as an arrangement diameter of the respiratory passages 51),
φD2: outer diameter of the spring means 41 (compression coil spring),
φD3: outer diameter of armature 44,
φD4: This will be described as the inner diameter of the spring chamber 43.

Here, the axis of the armature 44 coincides with the axis of the push rod 26.
The axis of the spring chamber 43 coincides with the axis of the guide insertion hole 55.
The spring means 41 is arranged on the outer periphery of a cylindrical stopper 31 arranged at the axis of the spring chamber 43, and the axis of the spring means 41 substantially coincides with the axis of the spring chamber 43.
A plurality of breathing passages 51 are provided in the armature 44, and each breathing passage 51 is provided on a radius starting from the axis of the armature 44.
The spring chamber 43 covers the outer periphery of the spring means 41 so as not to inhibit the expansion and contraction of the spring means 41, and the inner diameter dimension φD4 of the spring chamber 43 is larger than the outer diameter dimension φD2 of the spring means 41 ( φD4> φD2).
Furthermore, in order to form the magnetic attraction portion 47 on the opposing surface of the stator 49 and the armature 44, the outer diameter dimension φD3 of the armature 44 is provided larger than the inner diameter dimension φD4 of the spring chamber 43 (φD4 <φD3).

(Problem 1 of Reference Example 2 )
As in Reference Example 2, the structure is such that the spring chamber 43 on the upper side of the armature 44 and the inside of the guide insertion hole 55 (valve chamber) on the lower side of the armature 44 communicate with each other through a breathing passage 51 formed through the armature 44. When employed, the magnetic suction part 47 side (spring chamber 43 side) of the respiratory passage 51 may be blocked by the end of the stator 49 or the spring means 41 that partitions the spring chamber 43.

(Defect 2 of Reference Example 2 )
As in Reference Example 2, the structure is such that the spring chamber 43 on the upper side of the armature 44 and the inside of the guide insertion hole 55 (valve chamber) on the lower side of the armature 44 communicate with each other through a breathing passage 51 formed through the armature 44. When employed, when the arrangement diameter φD1 of the plurality of breathing passages 51 is increased, the magnetic path area in the armature 44 is reduced, and the magnetic attractive force of the armature 44 by the solenoid 45 is reduced.
In order to avoid this decrease in magnetic attractive force, the magnetic path area in the armature 44 is increased. However, if the outer diameter φD3 of the armature 44 is increased to increase the magnetic path area, the size of the pressure reducing valve 11 is increased.

(Feature 1 of Reference Example 2 )
Therefore, in this reference example 2 , in order to avoid the above problems 1 and 2, the breathing passage 51 is opened so as to straddle the inner peripheral surface of the stator 49 that defines the spring chamber 43 in the radial direction. The arrangement diameter φD1 of the breathing passage 51 is set within the range of the outer diameter dimension φD2 of the spring means 41 and the inner diameter dimension φD4 of the spring chamber 43 (φD2 ≦ φD1 ≦ φD4).
As a result, the breathing passage 51 can always communicate with the inside of the spring chamber 43, and the spring chamber 43 and the guide insertion hole 55 (valve chamber) can always communicate with each other via the breathing passage 51.
Further, by providing the arrangement diameter φD1 of the respiratory passage 51 to be equal to or smaller than the inner diameter dimension φD4 of the spring chamber 43, it is possible to avoid the problem that each respiratory passage 51 reduces the magnetic path area.

(Feature 2 of Reference Example 2 )
On the other hand, in the reference example 2 , as described above, the plurality of breathing passages 51 are formed in the armature 44. The plurality of breathing passages 51 are provided on the circumference of the arrangement diameter φD1, and are arranged so as to be symmetrical with respect to the axis when the armature 44 is viewed from the axial direction. Specifically, the central axes of the plurality of respiratory passages 51 are arranged at equal intervals (equal intervals) on the virtual circle. That is, when the number of the respiratory passages 51 is two, they are provided at intervals of 180 °, at three intervals at 120 ° intervals, and at four intervals at 90 ° intervals. An example in which the number of the respiratory passages 51 is two is shown in FIG.

  As described above, by providing the plurality of breathing passages 51 at equal intervals, it is possible to avoid the trouble that the breathing passage 51 disturbs the suction balance of the armature 44 and to avoid the balance disturbance that the flow resistance of the breathing passage 51 gives to the armature 44. it can. That is, when the armature 44 is driven, the armature 44 can be prevented from being inclined or eccentric. As a result, it is possible to avoid the problem that the tilting force is generated in the push rod 26 due to the inclination or eccentricity of the armature 44.

[Modification]
In the above reference examples and embodiments , the application example of the valve device ( particularly the pressure reducing valve 11) for adjusting the valve opening pressure and the fluid flow rate in the electromagnetic actuator 42 has been shown. You may apply to an actuator.
In the above reference examples and examples , the electromagnetic actuator 42 drives the push rod 26. However, the electromagnetic actuator 42 may drive a valve body (for example, a spool of a spool valve).
In the above Reference Examples and Examples, although the application to the electromagnetic actuator 42 mounted to the valve device (in particular pressure reducing valve 11), applied to an electromagnetic actuator other than the valve device (e.g., an industrial robot, etc.) May be.

FIG. 2 is a cross-sectional view of a pressure reducing valve and a cross-sectional view of a main part of a movable part (armature + push rod) of an electromagnetic actuator (conventional example and reference example 1 ). It is a schematic diagram of a common rail type fuel injection device. It is a figure which shows the groove | channel provided in sectional drawing of a pressure-reduction valve, and the lower end surface of a stopper ( Example ). It is sectional drawing of a pressure-reduction valve, and principal part sectional drawing of the movable part (armature + push rod) of an electromagnetic actuator ( reference example 2 ). FIG. 3 is a cross-sectional view of a main part of a pressure reducing valve and a cross-sectional view seen from the axial direction of an armature ( Reference Example 2 ).

1 Common rail 11 Pressure reducing valve (valve device)
22 Driving means 26 Push rod (shaft)
31 Stopper 35 Valve port (flow path)
41 Spring means (compression coil spring)
42 Electromagnetic Actuator 43 Spring Chamber 44 Armature 46 Coil 47 Magnetic Attraction 48 Magnetic Delivery 49 Stator 51 Breathing Path
63 groove
A Clearance

Claims (8)

A coil that generates a magnetic force when energized, an armature made of a magnetic member that is supported so as to be displaceable in the axial direction, and a magnetic attraction unit that magnetically attracts the movable part including the armature in the axial direction by the magnetic force generated by the coil Covering the outer periphery of the armature, arranged with a clearance between the armature, a magnetic delivery part for transferring the magnetic force generated by the coil from the radial direction to the armature, and a magnetic attraction part side of the movable part In an electromagnetic actuator comprising a stopper that abuts against the end surface and limits axial displacement of the movable part toward the suction side ,
In the movable part ,
A breathing passage is provided from the end surface on the magnetic attraction unit side ;
On the contact surface of the stopper with the movable part,
An electromagnetic actuator comprising a groove for preventing the breathing passage from being blocked . The electromagnetic actuator according to claim 1,
The electromagnetic actuator according to claim 1, wherein the breathing passage is formed so as to penetrate in the axial direction in the movable portion . The electromagnetic actuator according to claim 1,
In the center of the movable part, a shaft that is fixed in a penetrating manner in the axial direction is provided,
The electromagnetic actuator , wherein the breathing passage is formed in the shaft . The electromagnetic actuator according to claim 3, wherein
The electromagnetic actuator according to claim 1, wherein the stopper is in contact with an end surface of the shaft to limit axial displacement of the movable part toward the suction side . In the electromagnetic actuator in any one of Claims 1-4 ,
The groove electromagnetic actuator characterized that you open the breathing passage in the radial direction. The electromagnetic actuator according to any one of claims 1 to 5,
The electromagnetic actuator according to claim 1, wherein the groove is a cross groove . In the electromagnetic actuator in any one of Claims 1-6,
This electromagnetic actuator is characterized in that a valve body that opens and closes a flow path or adjusts a flow rate of a fluid passing through the flow path is driven in an axial direction. The electromagnetic actuator according to any one of claims 1 to 7,
This electromagnetic actuator is an electromagnetic actuator characterized in that it is a drive means for a pressure reducing valve capable of reducing the actual rail pressure of a common rail that stores high pressure fuel in a common rail fuel injection device.

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