JP2008255981A - Pressure switching valve device and injector equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure switching valve device of a structure to suppress generation of cavitation erosion, and an injector equipped with the device capable of maintaining an accurate fuel injection control. <P>SOLUTION: The pressure switching device 10 includes a control pressure chamber 101 into which high-pressure fluid 200 is introduced, a low-pressure fluid passage 105 maintained at a low pressure, a choked fluid passage 104 communicating the control pressure chamber 101 and the low-pressure fluid passage 105, and a valve element 160 for opening and closing the choked fluid passage 104. The device 10 opens and closes the valve element 160 to control flowing out of the high-pressure fluid 200 from the control pressure chamber 101 to the low-pressure fluid passage 105 and thereby increasing and decreasing a pressure of the control pressure chamber 101. The choked passage 104 includes a plurality of choked passages opened at one end in a surface 102 closed by the valve element 160 when the valve element 160 is closed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to suppression of the progress of cavitation erosion of a pressure switching valve device.

In recent years, as an injector used in a common rail fuel injection device for a diesel engine, high pressure fuel accumulated by the common rail is supplied to the fuel chamber in the injection nozzle, and the needle for opening and closing the injection hole is pressed in the valve closing direction. Supply to the needle back pressure chamber that generates back pressure, and increase or decrease the needle back pressure by an actuator such as a solenoid or piezo stack to switch between fuel injection and stop, and freely set the injection timing and injection amount Are widely used.

Patent Document 1 discloses an injector that reduces the load on an actuator by using a pressurized fuel as control oil to drive a control valve that controls needle back pressure.

An injector 1d having a conventional structure shown in FIG. 14 has an injection nozzle portion for injecting and stopping the fuel 200 accumulated at a high pressure from an injection hole 120 provided at the tip of a cylindrical base 125 by opening and closing the injection hole 120. 12 and a needle 122 that opens and closes the nozzle hole 120 by vertical movement.
A pressure switching valve device 10d for controlling the vertical movement of the needle 122 by switching the level of the back pressure of the needle 122, and an actuator 13 for driving the pressure switching valve device 10d,
14.

The pressure switching valve device 10d is connected to the high-pressure fuel flow path 151 filled with the high-pressure fuel 200 accumulated at a high pressure and the low-pressure fuel flow path 106 filled with the vegetation of the low-pressure fuel 300 maintained at a low pressure by the common rail 2. The control pressure chamber 101, the throttle passage 104d communicating the low pressure fuel passage 106 and the control pressure chamber 101, and the throttle passage 104d is opened and closed by the valve body 160 to control the control chamber 101 of the high pressure fuel 200. To the low-pressure flow path 105 is controlled.

The high-pressure fuel 200 is supplied to the needle back pressure chamber 127 through the control pressure chamber 101 and is supplied to the fuel chamber 123 formed in the injection nozzle portion 12, and the low-pressure fuel passes through the low-pressure channel 140. To the fuel tank 3.

The actuators 13 and 14 include a solenoid unit 14 and a braking unit 13, and the solenoid 1
The brake valve 132 interlocked with the armature 143 is opened and closed by energization opening and closing 41. As the brake valve 132 is opened and closed, the valve body 160 of the pressure switching valve device 10d moves up and down to open and close the throttle passage 104d.
When the valve body 160 is opened, the high-pressure fuel 200 in the needle back pressure chamber 127 is transferred to the control pressure chamber 10.
1, the high pressure fuel 200 in the fuel chamber 123 presses the needle 122 in the separating direction, the nozzle hole 120 is opened, and the high pressure fuel 200 is injected into the nozzle hole 120. Is injected from.
When the valve body 160 is closed, the needle 122 is pressed in the seating direction by the high-pressure fuel 200 introduced into the needle back-pressure chamber 127 from the high-pressure channel 151 through the control pressure chamber 101, and the injection hole 1
20 is closed and fuel injection is stopped.
The separation / seating seat of the needle 122 is controlled by increasing or decreasing the pressure in the needle back pressure chamber 127, and the injection and stop of the high-pressure fuel 200 from the injection hole 120 can be controlled.
JP 2006-257874 A

However, in such an internal combustion engine injector 1d, the high-pressure fuel 200 in the control pressure chamber 101 is stored at an extremely high pressure of 200 MPa, while the low-pressure fuel 300 in the low-pressure channel 105 is The atmospheric pressure is maintained at about 0.1 MPa.
Therefore, the valve body 160 is opened, and the high-pressure fuel 200 in the control pressure chamber 101 is throttled.
When jetting into the low-pressure channel 105 from 4d, extremely high pressure fuel is momentarily exposed to low pressure.

As shown in FIG. 12, when a fluid placed under high pressure (P ₁ ) is momentarily moved under low pressure (P ₀ ) and exposed to a pressure lower than the vapor pressure of the fluid, the fluid in a liquid state is vaporized. Cavitation occurs.
Furthermore, when this cavitation collides with the inner wall surface of the flow path or the pressure of the surrounding fluid rises, the cavitation collapses and condenses into a liquid.
At this time, it is known that a very high impact pressure is generated.

Therefore, in the pressure switching valve device 10d of the injector 1d, as shown in FIG. 13A, the valve body 160 is opened, and the high pressure fluid 200 passes through the throttle channel 104d and the low pressure in the low pressure channel 105. It is ejected as a high-pressure jet 201 into the fluid 300.
At this time, due to a rapid pressure drop, a cavitation layer 202 in which the high-pressure fuel 200 is vaporized is generated at the interface between the high-pressure jet 201 and the low-pressure fluid 300.
Furthermore, as shown in FIG. 13B, the high-pressure jet 201 collides with the surface of the inner wall 105 of the low-pressure channel 104 facing the throttle channel 104d together with the vortex 204 and the cavitation layer 202.
Cavitation collapse 204 occurs on the surface of the low-pressure flow path inner wall 106 due to the pressure of the collision. The cavitation collapse 204 is accompanied by an extremely high impact pressure, and as shown in FIG. 13C, the cavitation erosion 20 that scavenges the metal on the surface of the inner wall 106 of the low-pressure flow path.
6 may be caused.
Such cavitation erosion 206 gradually progresses over a long period of time, and the valve body 1
60 may be affected, and the accuracy of injector fuel injection control may be reduced.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a pressure switching valve device having a structure that suppresses the occurrence of cavitation erosion and an injector that can maintain accurate fuel injection control. To do.

In the first aspect of the invention, the control pressure chamber into which the high pressure fluid is introduced from the high pressure channel, the low pressure channel maintained at a low pressure, the throttle channel communicating the control pressure chamber and the low pressure channel, and the throttle flow A pressure switching valve device that controls the outflow of high-pressure fluid from the control pressure chamber to the low-pressure flow path by opening and closing the valve body, and increases or decreases the pressure in the control pressure chamber. A plurality of the throttle channels having one end opened in a plane closed by the valve body when the valve body is closed.

According to the first aspect of the present invention, when the high-pressure fluid in the control pressure chamber is ejected from the throttle channel to the low-pressure channel, a plurality of cavitation collision positions on the opposing inner walls of the low-pressure channel are concentrated in one place. Can be dispersed in locations.
In addition, the flow velocity of the high-pressure jet is rapidly reduced in inverse proportion to the number of throttle channels, and the collision time of the high-pressure jet against the inner wall of the low-pressure channel can be shortened.
Furthermore, the vortex formed around the high-pressure jets ejected from a plurality of constricted flow paths, the high-pressure jets interfere with each other, causing cavitation to collapse before colliding with the inner wall of the low-pressure flow path. The number of cavitations that collide with the inner wall of the low-pressure channel can be reduced.
Therefore, the occurrence of cavitation erosion on the inner wall surface of the low-pressure channel is suppressed, and the consumption of the pressure switching valve device can be suppressed.

According to a second aspect of the present invention, the plurality of throttle channels are provided at an angle at which virtual central axes, the central axes of which are extended, intersect each other in the low-pressure channel.

According to the invention of claim 2, before the plurality of high-pressure jets ejected from the control pressure chamber collide with the inner wall of the low-pressure channel, they collide with each other in the low-pressure channel to cause cavitation collapse, The number of colliding cavitations is reduced.
Therefore, the occurrence of cavitation erosion on the inner wall surface of the low-pressure channel is further suppressed,
The consumption of the pressure switching valve device can be suppressed.

In the invention of claim 3, the plurality of throttle channels are divided into jet directions of jets ejected from one throttle channel constituting the plurality of throttle channels and jet directions of jets ejected from the other throttle channels. Are arranged in a direction opposite to each other, and the central axes of the jetting directions that are the opposite directions are arranged on substantially the same line so that the jets from the opposite directions collide with each other.

According to the invention of claim 3, before the high pressure fluids ejected from the throttle channel collide with each other and reach the inner wall of the low pressure channel, the injection pressure is canceled and the cavitation collapses.
Therefore, the occurrence of cavitation erosion is further suppressed without causing cavitation collapse on the inner wall surface of the low pressure flow path, and consumption of the pressure switching valve device can be suppressed.

According to a fourth aspect of the present invention, in the pressure switching valve device according to the third aspect, the valve body is formed with a concave portion in which the surface side closed by the valve body is recessed in a concave shape, and a plurality of recesses are formed inside the concave portion. And the jet collision chamber region in which jets from opposite directions collide with each other.

According to the invention of claim 4, a plurality of jets from opposite directions collide with each other in the jet collision chamber region, the cavitation collapses, the jet jet pressure decreases, and the jet jets into the low-pressure channel. Cavitation will not occur again. Therefore, cavitation collapse on the inner wall of the low-pressure channel does not occur, and consumption of the pressure switching valve device can be suppressed.

According to a fifth aspect of the present invention, an injection nozzle portion that performs injection and stop of fuel accumulated at high pressure from an injection hole provided at the tip of a cylindrical base body by opening and closing the injection hole, and the injection hole by vertical movement. In an injector comprising: a needle that opens and closes; a pressure switching valve device that controls the vertical movement of the needle by switching the pressure of the back surface of the needle; and an actuator that drives the pressure switching valve device. The pressure switching valve device according to any one of claims 1 to 3 is provided as a switching valve device, the control chamber is provided on the back surface of the needle, and the valve body is opened and closed by the actuator. The needle is moved up and down by increasing or decreasing the pressure in the control pressure chamber.

According to the invention of claim 5, occurrence of cavitation erosion in the pressure switching valve device is suppressed, and accurate fuel injection control in the injector can be maintained.

A pressure switching valve device 10 according to a first embodiment of the present invention will be described with reference to FIGS.
1A is a cross-sectional view showing the configuration of the pressure switching valve device 10 according to the first embodiment of the present invention, FIG. 1B is a plan view taken along the line AA in FIG. 1C, and FIG. It is a cross-sectional schematic diagram which shows the effect of this embodiment.
As shown in FIGS. 1 (a) and 1 (b), the pressure switching valve device 10 is formed in a control pressure chamber 101 and a base body 100 as a high-pressure channel into which a high-pressure fluid 200 maintained at a high pressure is introduced. The low-pressure channel 105 filled with the maintained low-pressure fluid 300 and the throttle channel forming unit 10 of the base body 100
3, a plurality of throttle channels 104 that communicate the control pressure chamber 101 and the low-pressure channel 105, and a valve body 160 that opens and closes the throttle channel 104.
One end of the throttle channel 104 opens to the control pressure chamber 101 side in the throttle channel valve closing surface 102 that is closed by the valve element valve closing surface 161 when the valve element 160 of the throttle channel forming unit 103 is closed. A plurality of the other ends are arranged side by side so as to open to the low-pressure channel 105 side.
The pressure switching valve device 10 of the present invention can control the outflow of the high-pressure fluid 200 from the control pressure chamber 101 to the low-pressure channel 105 by opening and closing the valve body 160 to increase or decrease the pressure in the control pressure chamber 101.

As shown in FIG. 1C, when the valve body 160 is opened, the high-pressure fluid 20 in the control pressure chamber 101 is opened.
0 is ejected from the throttle channel 104 into the low pressure channel 105 as a high pressure jet 201.
A cavitation 202 layer is generated at the interface between the high pressure jet 201 and the low pressure fluid 300 due to the pressure difference between the pressure of the high pressure jet 201 and the surrounding constant pressure fluid 300.
However, the high-pressure jets 201 interfere with each other due to the vortex flow 204 formed around the high-pressure jets 201 ejected from the plurality of throttle channels 104.
Thus, before the cavitation 202 collides with the inner wall 106 of the low pressure flow path, the cavitations 202 collide with each other, and the cavitation collapse 20 occurs in the low pressure flow path 105.
4, the number of cavitations 202 that collide with the inner wall 106 of the low-pressure flow path can be reduced.

Further, the collision range 205 of the cavitation 202 on the inner wall 106 of the low-pressure flow path can be dispersed over a wide range without being concentrated in one place, as compared with the case where there is a single throttle flow path 104.
Therefore, the occurrence of cavitation erosion on the surface of the low pressure flow path inner wall 106 is dispersed without being concentrated in one place, so that the consumption of the low pressure flow path inner wall 106 is remarkably suppressed.
Therefore, durability of the pressure switching valve device 10 is improved, and accurate pressure switching control can be maintained for a long time.

FIG. 2A shows a control pressure chamber 101 having a constant volume and a low pressure channel 105 having a plurality of throttle channels 104.
6 is a characteristic diagram showing the relationship between the number of throttle channels 104, the ejection velocity ν of the high-pressure jet 201, and the ejection time t when communicating with each other.
As shown in FIG. 2A, the initial velocity v ₀ at which the high-pressure fluid 201 is ejected at the moment when the throttle channel 104 provided in the control pressure chamber 101 is opened is constant regardless of the number of throttle channels 104. is there.
However, the reduction rate of the ejection velocity ν increases in proportion to the number of throttle channels 104, the ejection velocity ν decreases in a quadratic function, and the ejection time t is inversely proportional to the number of throttle channels 104. Become shorter.
Therefore, as the number of throttle channels 104 increases, the flow velocity ν of the high-pressure jet 201 decreases more quickly, and the collision time of the high-pressure jet 201 with the low-pressure channel inner wall 106 can be shortened.

Further, the total number of cavitations that occur when the control pressure chamber 101 and the low pressure channel 105 communicate with each other is considered to be constant regardless of the number of throttle channels 104, but as shown in FIG.
As the number of throttle channels 104 increases, the inner wall 1 of the low-pressure channel facing the throttle channel 104 is opposed.
The number of cavitations 202 that collide with 06 decreases inversely.

A pressure switching valve device 10a according to a second embodiment of the present invention will be described with reference to FIGS.
Note that the same components as those in the first embodiment are denoted by the same reference numerals, and thus the description thereof is omitted (the same applies to other embodiments described below).
3A is a cross-sectional view showing the configuration of the pressure switching valve device 10a according to the second embodiment of the present invention, FIG. 3B is a plan view taken along the AA plane in FIG. It is a cross-sectional schematic diagram which shows the effect of this embodiment.
As shown in FIGS. 3A and 3B, in the present embodiment, a plurality of throttle channels 104a are extended in the throttle channel closing surface 102 of the throttle channel forming portion 103 and the central axis thereof extends. The virtual center axes are provided at an angle θ that intersects each other in the low-pressure channel 105.
For example, in the present embodiment, the crossing angle θ formed by the two throttle channels 104a is set to about 30 °.

Therefore, as shown in FIG. 3C, when the valve body 160 is opened, the high pressure jet 201 collides with each other before reaching the low pressure flow path inner wall 106 facing the throttle flow path 104a, and the low pressure flow path 1
Causes cavitation collapse 204 within 05.
In the present embodiment, the central axis of the throttle channel 104a is provided obliquely with respect to the low-pressure channel inner wall 106, so the central axis of the throttle channel 104a is provided at a right angle to the low-pressure channel inner wall 106. In this case, the length of the jet process until the high-pressure jet 201 reaches the low-pressure channel inner wall 106 can be made longer than the distance D from the opening of the throttle channel 104a to the low-pressure channel inner wall 106. .

Here, FIG. 4 shows the relationship between the distance from the ejection hole and the impact force generated when cavitation collapses when the high-pressure fluid is ejected into the low-pressure fluid.
In general, it is known that there are two peaks in the impact at the time of cavitation collapse, and the first peak decreases rapidly as the distance from the ejection hole increases.
Therefore, in the present embodiment, the distance until the high-pressure jet 201 ejected from the throttle channel 104a reaches the low-pressure channel inner wall 106 is set so as to be in the region indicated by the hatched portion in FIG. Further, it can be expected that the impact force generated when the cavitation collapses is reduced to further reduce cavitation erosion.

The number of throttle channels 104 is not limited to two as shown in the above embodiment,
As shown in FIG. 5 (a), any number may be provided as long as it is within the throttle channel closing surface 102 closed by the valve body 160.

Further, as shown in FIG. 5B, a plurality of throttle channels 104b having different inner diameters may be provided.
In this case, since the direction, strength, and the like of the vortex flow 204 generated around the high-pressure jet 201 for each throttle channel varies, the position of the cavitation collapse 204 in the low-pressure channel 105 is further dispersed, and the low-pressure channel It is considered that the occurrence of cavitation erosion on the inner wall 106 surface can be suppressed.

Further, as shown in FIG. 5C, the throttle channel 104e may be provided in a different shape.
By making the throttle channel 104e irregular, the vortex generated around the high-pressure jet is complicated, the position of cavitation collapse in the low-pressure channel is dispersed, and cavitation erosion occurs on the inner wall surface of the low-pressure channel. It can be suppressed.

FIG. 6A is a cross-sectional view showing the configuration of the pressure switching valve device 10c in the third embodiment of the present invention, FIG. 6B is a plan view taken along the line AA in FIG. It is a cross-sectional schematic diagram which shows the effect of this embodiment.
In the present embodiment, the plurality of throttle channels 104c are provided such that the injection directions of the high-pressure fluid 201 ejected from the throttle channels 104c face each other.
Specifically, the throttle channel forming portion 103c is formed so as to project from the low pressure channel 105 toward the control pressure chamber 101, and a plurality of throttle channels 104c are projected from the side surface of the throttle channel forming portion 103c. A jet collision chamber region 105c is formed in the projecting portion to collide jets from opposite directions.

Further, the valve body 160 has a concave portion 165 in which a surface side closed by the valve body 160 is recessed in a concave shape.
A plurality of throttle channels 104c and jet collision chamber regions 105c formed in the protruding portion are disposed inside the recess 165.
The flat surface portion 102c outside the projecting portion and the valve element closing surface 161c are in close contact with each other so that the throttle channel 104
c is in a closed state.

As shown in FIG. 6C, in the present embodiment, the high-pressure jets 201 collide with each other in the jet collision chamber region 105c, the jetting pressure is reduced, and the cavitation collapse 203 occurs.
When the high-pressure fluid 200 whose pressure has decreased from the jet collision chamber region 105 c flows into the low-pressure channel 104, the pressure decreases to a pressure at which cavitation does not occur again, and cavitation erosion on the surface of the low-pressure channel inner wall 106 Is thought to be avoided.

By applying the pressure valve device of the present invention to an injector, cavitation erosion in the pressure valve device is suppressed, and accurate fuel injection control in the injector can be maintained.
A configuration of an injector 1 for injecting high-pressure fuel into an internal combustion engine to which the pressure switching valve device 10 shown in the first embodiment of the present invention is applied will be described with reference to FIGS.

FIG. 7 is a cross-sectional view of the injector 1 to which the pressure switching valve device of the present invention is applied, and FIG. 8 is an enlarged cross-sectional view showing the main part thereof.
The injector 1 includes an injection nozzle portion 12 that performs injection and stop of the fuel 200 accumulated at a high pressure from an injection hole 120 provided at the tip of a cylindrical base 125 by opening and closing the injection hole 120, and an injection hole by vertical movement. A needle 122 that opens and closes 120, a pressure switching valve device 10 that is provided on the back surface side of the needle 122 and controls the vertical movement of the needle 122 by switching the pressure level on the needle back surface, and a valve body 160 of the pressure switching valve device 10. A valve body back pressure control unit 11 for controlling the back pressure of
Actuators 13 and 14 that drive the pressure switching valve unit 10 via the valve body back pressure control unit 11
And.

The injector 1 is connected to a common rail 2, a fuel tank 3, and a control device (not shown), and introduces a fuel 200 accumulated at a high pressure by the common rail 2 from a high-pressure fuel flow path 151 provided in the base end portion 15. The low-pressure fuel 300 is returned from the low-pressure fuel flow path 152 to the fuel tank 3.

The pressure switching valve device 10 according to the present embodiment includes a control pressure chamber 101 connected to a high pressure fuel passage 151 filled with a high pressure fuel 200 and a low pressure fuel passage 105 maintained at a low pressure, and a low pressure fuel passage 105. And a plurality of throttle passages 104 communicating with the control pressure chamber 101, and the valve body 16
The throttle channel 105 is opened and closed by 0 to control the outflow of the high-pressure fuel 200 from the control chamber 101 to the low-pressure channel 105, and the pressure in the control pressure chamber 101 is increased or decreased.

The throttle channel 104 is closed by a valve body closing surface 161 of the throttle channel forming part 103 formed in the distance piece 100 that is the base of the pressure switching valve device 10.
A plurality of them are provided side by side, with one end opening to the control pressure chamber 101 side and the other end opening to the low pressure flow path 104 side.

The high-pressure fuel 200 introduced from the high-pressure fuel flow path 151 is branched from the main flow path 111 and supplied to the needle back pressure chamber 127 via the control pressure chamber 101, and the fuel supply path 108 formed in the distance piece 100. The fuel chamber 1 formed in the injection nozzle portion 11 through the
23.

The pressure switching valve device 10 is provided on the back side of the needle 122, and controls the inflow of the high-pressure fuel 200 supplied into the needle back pressure chamber 127 into the low-pressure channel 104 by opening and closing the valve body 160. The pressure on the back surface of the needle 122 is controlled by increasing / decreasing the pressure in the pressure chamber 101 to move the needle 122 up and down.
Further, the distance piece 100 communicates with the low-pressure flow path 105 and is connected to the external fuel tank 3.
A low-pressure fuel return passage 107 connected to is formed.

The valve body 160 is driven to open and close by the actuators 13 and 14 via the valve body back pressure control unit 11.
The valve body back pressure control unit 11 includes a valve body back pressure control unit base 110, a main channel 111 communicating with the high pressure fuel channel 151, branch channels 112, 113, 114, and a part of the control pressure chamber 101. The control pressure chamber forming portion 115 to be formed, the valve body holding portion for slidably holding the valve body 160, the valve body back pressure chamber 115 formed on the back surface of the valve body 160, the valve body back pressure chamber 115 and the low pressure The communication path 117 communicates with the chamber 134, the low-pressure recirculation path 118 communicates with the low-pressure fuel recirculation path 107, and the coil spring 116 that urges the valve body 160 in the valve closing direction.
The high-pressure fuel 200 branched from the main flow path 111 is a back pressure flow path 1 formed in the valve body 160.
63, the valve body 160 is introduced into the valve body back pressure chamber 115 formed on the back surface of the valve body 160.
When the communication path 117 is opened and closed by the actuators 13 and 14,
The pressure in the valve body back pressure chamber 115 increases or decreases, and the valve body 160 moves up and down.

The actuators 13 and 14 are constituted by a solenoid part 14 and a braking part 13. The braking unit 13 includes a braking valve valve body 134 that is fixed to the distal ends of the braking valve needle 132 and the control valve needle 131, and a cylindrical base 131 that holds the braking valve 132 so as to be slidable.

The solenoid unit 14 includes an armature 143, a coil spring 142 that biases the armature 143 in the valve closing direction, a solenoid 141, and an energization line 140 that energizes the solenoid 141.
The armature 143 is fixed to the rear end of the brake valve 131, and the brake valve 132 interlocked with the armature 143 is opened / closed by energization opening / closing of the solenoid 141.
When the solenoid 141 is energized, the armature 143 is attracted and the brake valve 132 is opened. When the solenoid 141 is closed, the biasing coil spring 142 causes the brake valve 132 to open.
Closes.
By opening and closing the brake valve 132, the pressure in the valve body back pressure chamber 115 increases or decreases, and the pressure switching valve device 1
The zero valve body 160 moves up and down.

The base end portion 15 includes an injector base 150 and a high pressure fuel supply portion 151 for introducing the high pressure fuel 200 from the common rail 2 and a low pressure fuel discharge portion 152 for returning the low pressure fuel 300 to the fuel tank 3.
And a terminal portion that is connected to a control device (not shown) and energizes the actuator 14.

The valve body 160 opens and closes the throttle flow path 104 at the valve body closing surface 161 and the rear valve closing surface 1.
At 62, the high-pressure fuel 200 is supplied to the control pressure chamber 101 and stopped.
When the valve body 160 is raised, the supply of the high-pressure fuel 200 to the control pressure chamber 101 is stopped, the throttle channel 104 is opened, and the high-pressure fuel 200 in the needle back pressure chamber 127 is controlled to the control pressure chamber 1.
01 is discharged from the throttle channel 104 to the low pressure channel 105, the pressure in the needle back pressure chamber 127 decreases, the high pressure fuel 200 in the fuel chamber 123 presses the needle 122 in the seating direction, and the injection hole 120. Is opened, and the high-pressure fuel 200 is injected from the injection hole 120.

When the valve body 160 is lowered, the high-pressure fuel 200 is supplied to the control pressure chamber 101, the throttle channel 104 is closed, the pressure in the control pressure chamber 101 is increased, and further introduced into the needle back pressure chamber 127. The needle 122 is pressed in the seating direction by the high-pressure fuel 200, the nozzle hole 120 is closed, and fuel injection is stopped.
The separation / seating seat of the needle 122 is controlled by increasing or decreasing the pressure in the needle back pressure chamber 127, and the injection and stop of the high-pressure fuel 200 from the injection hole 120 can be controlled.

FIG. 9A is a sectional view of the distance piece 100 in the injector 1 to which the pressure switching valve device 10 according to the first embodiment of the present invention is applied, and FIG. 9B is a plan view thereof.
As shown in FIG. 9, the distance piece 100 includes a valve body 16 of the throttle channel forming portion 103.
Plural such that one end opens to the control pressure chamber 101 side and the other end opens to the low pressure channel 105 side in the throttle channel closing surface 102 that is closed by the valve closing surface 161 when the zero valve is closed. Are arranged side by side. By forming the distance piece 100 in this way, the pressure switching valve device 10 according to the first embodiment of the present invention can be applied to the injector 1 very easily. According to the present embodiment, as in the first embodiment, cavitation erosion of the low pressure flow path inner wall 106 is suppressed, and accurate fuel injection control in the injector 1 can be maintained.

Fig.10 (a) is sectional drawing of the distance piece 100a in the injector 1 to which the pressure switching valve apparatus 10a in the 2nd Embodiment of this invention is applied, (b) is the top view. In the present embodiment, the basic configuration is the same as that of the injector 1 to which the pressure switching valve device 10 in the first embodiment described above is applied, so only the characteristic part will be described.
As shown in FIG. 10, the distance piece 100 a includes a plurality of throttle channels 104 a in the throttle channel closing surface 102 of the throttle channel forming unit 103, and a virtual central axis whose central axis is extended has a low pressure. They are provided at angles that intersect each other in the flow path 105.
For example, in the present embodiment, the crossing angle formed by the two throttle channels 104a is set to about 30 °. By forming the distance piece 100a in this way, the pressure switching valve device 10a according to the second embodiment of the present invention can be applied to the injector 1 very easily.
Furthermore, if the throttle channel shown in FIG. 5 is appropriately formed in the distance piece 100, the same effect as described above can be expected.

FIG. 11 is an enlarged cross-sectional view of a main part of the injector 1 to which the pressure switching valve device 10c according to the third embodiment of the present invention is applied.
The throttle channel forming portion 103c formed in the distance piece 100c is provided with a plurality of throttle channels 104c so that the injection directions of the high-pressure fluid ejected from the throttle channel 104c face each other.
Specifically, the throttle channel forming portion 103c is formed so as to project from the low pressure channel 105 toward the control pressure chamber 101, and a plurality of throttle channels 104c are projected from the side surface of the throttle channel forming portion 103c. A jet collision chamber region 105c is formed in the projecting portion to collide jets from opposite directions.
Further, the valve body 160 has a concave portion 165 in which a surface side closed by the valve body 160 is recessed in a concave shape.
A plurality of throttle channels 104c and jet collision chamber regions 105c formed in the protruding portion are disposed inside the recess 165.
The flat surface portion 102c outside the projecting portion and the valve element closing surface 161c are in close contact with each other so that the throttle channel 104
c is in a closed state.
As described above, the pressure switching valve device according to the third embodiment of the present invention can be applied to an injector.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention. For example, in the above embodiment, an injector using a solenoid as an actuator has been described. However, the present invention can be appropriately adopted even when a piezo stack is used.

Further, in the above embodiment, the pressure switching valve device in which the valve body is placed in the high pressure flow path has been described, but also in the case of the pressure switching valve device in which the valve body is placed in the low pressure flow path, The present invention can be adopted as appropriate. In this case, the high-pressure jet injected from the high-pressure channel through the throttle channel may corrode the valve body in the low-pressure channel due to cavitation erosion, but the valve is formed by forming a plurality of throttle channels. It is possible to suppress wear due to body cavitation erosion.

(A) is sectional drawing which shows the structure of the pressure switching valve apparatus in the 1st Embodiment of this invention, (b) is an arrow top view in the AA surface in this figure, (c) is this implementation. The cross-sectional schematic diagram which shows the effect of a form. (A) is a characteristic diagram showing the relationship between the number of throttle channels and the jet velocity of the high-pressure jet, and (b) is a characteristic diagram showing the number of cavitations that collide with the number of throttle channels and the inner walls of the low-pressure channels facing each other. . (A) is sectional drawing which shows the structure of the pressure switching valve apparatus in the 2nd Embodiment of this invention, (b) is an arrow top view in the AA surface in this figure, (c) is this implementation. The cross-sectional schematic diagram which shows the effect of a form. The characteristic figure which shows the impact force at the time of collapse of cavitation. (A), (b), (c) is a top view which shows another Example of the throttle flow path in the 1st, 2nd embodiment of this invention. (A) is sectional drawing which shows the structure of the pressure switching valve apparatus in the 3rd Embodiment of this invention, (b) is an arrow top view in the AA surface in this figure, (c) is this implementation. The cross-sectional schematic diagram which shows the effect of a form. These are sectional drawings which show the structure of the injector which comprises the pressure switching valve apparatus of this invention. The principal part expanded sectional view of the injector shown in FIG. (A) is sectional drawing of the distance piece used for the injector in the 1st Embodiment of this invention, (b) is the top view. (A) is sectional drawing of the distance piece used for the injector in the 2nd Embodiment of this invention, (b) is the top view. Sectional drawing of the principal part of the injector in the 3rd Embodiment of this invention. The state diagram which shows the generation | occurrence | production mechanism of cavitation. The principal part sectional drawing which shows the generation | occurrence | production state of erosion from generation | occurrence | production of the cavitation in the conventional injector in order of (a)-(c). Sectional drawing which shows the structure of the conventional injector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pressure switching valve apparatus 101 Control pressure chamber 102 Restriction flow path valve closing surface 103 Restriction flow path formation part 104 Restriction flow path 105 Low pressure flow path 106 Low pressure flow path inner wall 160 Valve body 161 Valve body valve closing surface
200 High Pressure Fluid 201 High Pressure Jet 202 Cavitation 203 Cavitation Collapse 204 Vortex 300 Low Pressure Fluid

Claims (5)

A control pressure chamber into which high-pressure fluid is introduced from a high-pressure channel maintained at a high pressure; a low-pressure channel maintained at a low pressure; a throttle channel communicating the control pressure chamber and the low-pressure channel; and the throttle A pressure switching valve for controlling the outflow of the high-pressure fluid from the control pressure chamber to the low-pressure channel by opening and closing the valve body, and increasing or decreasing the pressure of the control pressure chamber. A device,
A pressure switching valve device, wherein a plurality of the throttle channels having one end opened in parallel within a throttle channel closing surface that is closed by the valve when the valve is closed. 2. The pressure switching valve device according to claim 1, wherein the plurality of throttle passages are provided at angles at which virtual central axes, the central axes of which are extended, intersect each other in the low-pressure passage. In the plurality of throttle channels, the jet direction of the jet ejected from one throttle channel constituting the plurality of throttle channels and the jet direction of the jet ejected from the other throttle channel are opposite to each other. 3. The pressure switching valve according to claim 1, wherein central axes of the injection directions that are opposite directions are arranged on substantially the same line so that the jets from the opposite directions collide with each other. 4. apparatus. The valve body is formed with a concave portion in which the surface side closed by the valve body is recessed in a concave shape, and the plurality of throttle channels and the jets from opposite directions collide with the inside of the concave portion. The pressure switching valve device according to claim 3, wherein a jet collision chamber region is formed. An injection nozzle part that performs injection and stop of fuel accumulated at high pressure from an injection hole provided at the tip of a cylindrical base by opening and closing the injection hole, and a needle that opens and closes the injection hole by vertical movement; In an injector comprising a pressure switching valve device that controls the vertical movement of the needle by switching the level of the back pressure of the needle, and an actuator that drives the pressure switching valve device,
The pressure switching valve device according to any one of claims 1 to 4 is provided as the pressure switching valve device,
An injector characterized in that the control chamber is provided on the back surface of the needle, and the needle is moved up and down by increasing or decreasing the pressure in the control pressure chamber as the valve body is opened and closed by the actuator.