JP5157976B2 - Flow control solenoid valve - Google Patents

Description

  The present invention relates to a flow control solenoid valve that controls a flow rate, and is particularly suitable for a flow control solenoid valve that controls the flow rate of fuel supplied to a high-pressure fuel pump in a common rail fuel injection system used in a diesel engine. .

  A common rail fuel injection system is known as a fuel injection system that injects fuel into an engine. In the common rail fuel injection system, a common pressure accumulation chamber (common rail) communicating with each cylinder of the engine is provided. The pressure of the fuel stored in the common rail is kept constant by pressurizing and supplying high pressure fuel at a required flow rate to the common rail from a high pressure fuel pump with variable fuel discharge. The high-pressure fuel stored in the pressure accumulation state on the common rail is injected into each cylinder from an injector connected to the common rail at a predetermined timing.

  In order to keep the fuel pressure stored in the common rail constant, the flow rate of fuel supplied to the high-pressure fuel pump is controlled according to the engine load condition, and the flow rate of fuel discharged from the high-pressure fuel pump is controlled. There is a need to. In a conventional common rail type fuel injection system, a flow control solenoid valve for controlling the flow rate of fuel is disposed between a high pressure fuel pump and a feed pump that supplies fuel to the high pressure fuel pump, and is supplied to the high pressure fuel pump. The flow rate of the fuel and the flow rate of the fuel discharged from the high-pressure fuel pump are controlled.

  Such a flow control solenoid valve has an electromagnetic drive means for driving the valve member in accordance with the applied current value. The amount of movement of the valve member is variable according to the current value applied to the electromagnetic drive means. Depending on the amount of movement of the valve member, the area of the opening formed in the valve body accommodating the valve member changes. Thereby, since the flow rate of the fuel passing through the opening is controlled, the flow rate of the fuel supplied to the high-pressure fuel pump is controlled (see, for example, Patent Document 1 and Patent Document 2).

Japanese translation of PCT publication No. 2002-530568 JP 2002-039420 A

  The flow control solenoid valve disclosed in Patent Literature 1 and Patent Literature 2 has a problem that the number of parts increases and the manufacturing cost increases because the rod and the valve are formed separately.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide a flow control electromagnetic valve capable of reducing the number of parts.

  The present invention employs the following technical means in order to achieve the aforementioned object.

According to the first aspect of the present invention, a cylindrical housing, a rod that extends along the axial direction of the housing, and is provided so as to reciprocately move toward the inner peripheral surface of the housing, and one end of the rod is slidable. A cylindrical valve body that is supported and fixed to the inner peripheral surface portion of the housing, and a movable core that is provided integrally with the rod at a position away from the valve body on the inner peripheral surface portion side of the housing in the axial direction and reciprocally moves together with the rod. A coil that generates a magnetic force toward the valve body when energized, and a spring that presses the rod in a direction away from the valve body. The housing includes an inner peripheral surface portion side and an outer peripheral surface portion. A first opening that communicates with the side is formed, and the valve body has a second opening that communicates between the inner peripheral surface side and the outer peripheral surface side of the valve body. The rod is formed with a passage space that is continuous with the inner peripheral surface side of the valve body and through which fluid flows, and a third opening that communicates the passage space with the outer peripheral surface side of the rod. The portion and the second opening are in communication with each other, and the movable core is formed in a cylindrical shape from a magnetic material, is provided in an intermediate portion excluding one end and the other end of the rod, and is fixed to the outer peripheral surface portion of the rod. The valve body is made of a non-metallic material having a small sliding resistance with the rod and further includes a bearing provided on the inner peripheral surface portion of the housing. One end of the rod is supported by the valve body and the other end of the rod is supported by the bearing, so that the movable core having a large sliding area is not supported by the bearing. Support To a doubly supported structure by the rod is reciprocally displaced, a flow control solenoid valve, wherein the opening area for the second opening of the third opening is changed.

  According to the first aspect of the present invention, a passage space through which fluid flows is formed in the rod. In addition, since the third opening is formed in the rod so that the passage space communicates with the outer peripheral surface side of the rod, the fluid flowing down the passage space flows from the third opening to the outside of the outer peripheral surface of the rod. Such a rod is provided so as to reciprocate on the inner peripheral surface side of the housing, and its position in the housing is controlled by electromagnetic force generated by energizing the coil and spring force.

  The housing is provided with a valve body that slidably supports one end of the rod. The housing and the valve body are each formed with a first opening and a second opening that communicate with the outer peripheral surface side. Therefore, by controlling the relative position (opening area) between the second opening and the third opening, the fluid flowing down the passage space of the rod causes the third opening, the second opening, and the first opening to move. Thus, the flow rate flowing down to the outer peripheral surface side of the housing can be controlled.

  Therefore, in the prior art described in Patent Document 1 and Patent Document 2 described above, the rod that is integral with the movable core and the valve for controlling the opening area are separate, but in the present invention, the rod is integral with the movable core. A certain rod has a function of controlling the opening area. Therefore, in the present invention, the function of the rod and the valve as described in the prior art can be realized by one component. As a result, the number of parts can be reduced and the manufacturing cost can be reduced as compared with the above-described conventional technology.

According to the first aspect of the present invention, since the valve body is made of a non-metallic material, the sliding resistance with the rod can be made smaller than that of the metallic material. In the prior art described in Patent Document 1 described above, since the movable core configured integrally with the rod is supported by the bearing, the sliding area where the movable core and the bearing slide is large. Furthermore, the rod slides with a housing made of metal. As a result, the rod has a large sliding resistance with the housing. As described above, in the configuration of the prior art, the sliding resistance due to the movable core, the rod, and the housing is large, and there is a risk of wear, so the change in sliding resistance with time increases. As a result, in the prior art, the lift position of the valve is deviated, causing the controllability of the lift position to deteriorate. Specifically, the lift position of the valve is caused by the force relationship of three forces of electromagnetic attraction force, sliding resistance and spring force (electromagnetic attraction force−sliding resistance = spring force). Of the three forces, the electromagnetic attractive force and the spring force are constant with little change over time, but the sliding resistance has a large change over time as described above. Therefore, there is a problem that the balance position changes when the sliding resistance changes.

  On the other hand, in the present invention, since the valve body is made of a non-metallic material as described above, the sliding resistance is smaller than that of the metal material, so that the change in sliding resistance with time is small. In other words, the sliding resistance can be made substantially constant. Therefore, it can suppress that the positioning accuracy of a rod becomes low resulting from the change of sliding resistance. Thereby, the controllability of the opening degree of the third opening can be maintained.

According to the first aspect of the present invention, since one end of the rod is supported by the valve body and the other end of the rod is supported by the bearing, it is a so-called doubly supported structure that supports both ends of the rod. By supporting not only one end but also both ends of the rod in this way, when the rod is reciprocally displaced, displacement in the direction intersecting the direction in which the rod reciprocates can be suppressed. Thereby, the continuity of the reciprocating displacement of the rod can be ensured.

Further, in the invention described in claim 2 , the spring is disposed between the inner peripheral surface portion of the housing and the outer peripheral surface portion of the rod, and is disposed in a space where the movable core and the valve body face each other, and one end of the spring is It contacts the body, and the other end of the spring contacts the movable core.

According to the invention described in claim 2 , since one end of the spring contacts the valve body and the other end contacts the movable core, there is no need to newly provide a receiving member for receiving one end of the spring. As a result, the manufacturing cost of the receiving member can be reduced. Moreover, since it is not necessary to provide a receiving member in the housing, the flow control solenoid valve can be miniaturized.

Further, in the invention according to claim 3 , the outer peripheral surface portion of the valve body is formed in a circumferential shape, the inner peripheral surface portion of the housing is formed in a circular shape, and the outer peripheral surface portion of the valve body is the inner peripheral surface portion of the housing. It is characterized by contacting with.

According to the invention of claim 3 , since the outer peripheral surface portion of the valve body is in contact with the inner peripheral surface portion of the housing, the fluid flowing down the first opening portion and the second opening portion causes the outer peripheral surface portion of the valve body and the housing to flow. It is possible to suppress the flow down between the inner peripheral surface portion. Thereby, it is possible to prevent the fluid from leaking out of the housing undesirably. Further, since the valve body and the housing have simple shapes, the processing can be simplified. This can further reduce the manufacturing cost.

Furthermore, the invention described in claim 4 further includes a filter that is provided on the inner peripheral surface side of the valve body and removes foreign matters in the fluid flowing down the valve body.

According to invention of Claim 4 , the foreign material in a fluid can be removed with a filter. Therefore, adverse effects due to foreign matter in the fluid can be suppressed.
According to the fifth aspect of the present invention, the passage space opens at the opening end of the rod located in the valve opening direction and extends in the valve closing direction, and the opening end side of the rod has the passage space inside. The bottom part of the passage space is located between the valve body and the movable core in the axial direction, and the bearing supports the closed end of the rod located in the valve closing direction. It is characterized by.

It is sectional drawing which shows the flow control electromagnetic valve 10 of 1st Embodiment. It is sectional drawing which shows 10 A of flow control solenoid valves of 2nd Embodiment.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. In some embodiments, portions corresponding to the matters described in the preceding embodiments are denoted by the same reference numerals, and redundant descriptions may be omitted. In addition, when a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those of the embodiment described in advance. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination does not hinder the combination.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a flow control electromagnetic valve 10 of the first embodiment. The flow control solenoid valve 10 is used as a component of a common rail fuel injection system (not shown) for a diesel engine, for example.

  First, the common rail fuel injection system will be briefly described. The common rail type fuel injection system includes a fuel tank that mainly stores fuel, an injector that injects fuel into a combustion chamber, a common rail that is provided with an injector, and a high pressure fuel pump that supplies high pressure fuel to the common rail, A feed pump for sending the fuel in the fuel tank to the high-pressure fuel pump, and a flow rate control solenoid valve 10 for controlling the flow rate of the fuel sent from the feed pump to the high-pressure fuel pump are provided. The fuel tank stores normal-pressure fuel, and the fuel inside the fuel tank is supplied to the flow control solenoid valve 10 by a feed pump.

  The flow rate control electromagnetic valve 10 is electrically controlled to adjust the flow rate of the fuel sent from the feed pump and supply it to the high pressure fuel pump. The flow control electromagnetic valve 10 includes a housing 11 extending in a predetermined axial direction Z (opening / closing direction Z), a valve body 12 provided in the housing 11, and a rod 13 accommodated in the housing 11 so as to be reciprocally displaceable in the axial direction Z. , A bearing 14 that supports the rod 13, and a drive unit 15 that drives the rod 13.

  Hereinafter, as the direction of the flow control electromagnetic valve 10, the direction in which the housing 11 extends is referred to as the axial direction Z (left and right direction in FIG. 1), and one of the axial directions Z is referred to as the valve opening direction Z1 (left side in FIG. 1). The other of the axial directions Z may be referred to as a valve closing direction Z2 (right side in FIG. 1).

  First, the housing 11 will be described. The housing 11 accommodates a part of the valve body 12, the rod 13, the bearing 14, and the drive unit 15 inside. The housing 11 is formed in a cylindrical shape extending in the axial direction Z. The housing 11 has an outer peripheral surface portion and an inner peripheral surface portion formed in a circumferential shape. The housing 11 is open at the end located in the valve opening direction Z1. The housing 11 is closed at the end located in the valve closing direction Z2. The housing 11 has a first magnetic part 16 having magnetism, a second magnetic part 17, and a nonmagnetic part 18 having no magnetism. The first magnetic part 16 is located in the valve opening direction Z1 with respect to the nonmagnetic part 18. The second magnetic part 17 is located in the valve closing direction Z2 relative to the nonmagnetic part 18. Therefore, the end portion of the housing 11 located in the valve closing direction Z <b> 2 becomes the second magnetic portion 17. Such a nonmagnetic part 18 prevents a magnetic short circuit between the first magnetic part 16 and the second magnetic part 17. The first magnetic part 16, the second magnetic part 17, and the nonmagnetic part 18 are integrally connected by, for example, laser welding. Further, the housing 11 may be partly magnetized or non-magnetic by, for example, thermal processing after being molded integrally.

  In addition, a stepped portion 19 that protrudes radially outward is formed on the outer peripheral surface portion of the housing 11. Such a stepped portion 19 is a portion that comes into contact with another device such as a feed pump. A first opening 20 through which fuel flows is formed in the side wall of the housing 11. Therefore, the first opening portion 20 penetrates the side wall of the housing 11 and communicates the inner peripheral surface portion side and the outer peripheral surface portion side of the housing 11. The first opening 20 is located closer to the valve opening direction Z1 than the step 19. The fuel that has flowed out of the housing 11 from the first opening 20 is supplied to the high-pressure fuel pump.

  Next, the valve body 12 will be described. The valve body 12 supports one end of the rod 13 so that the rod 13 can reciprocate. The valve body 12 has an inner peripheral surface portion and an outer peripheral surface portion formed in a circumferential shape. The valve body 12 is caulked and fixed to the end portion of the housing 11 located in the valve opening direction Z1 (this fixing may be press-fitting). The end of the valve body 12 located in the valve opening direction Z1 is located on the valve opening direction Z1 side from the end of the housing 11 located in the valve opening direction Z1. Therefore, the outer peripheral surface portion of the valve body 12 is in intimate contact with the inner peripheral surface portion of the housing 11.

  Further, the outer peripheral surface portion of the valve body 12 and the inner peripheral surface portion of the housing 11 may be clearance fit fitting. In the case of clearance fit fitting, the gap (clearance) to be set may be set to such an extent that fuel leakage from the gap to the first opening 20 is not affected. In the case of clearance fit fitting, measures against fuel leakage may be taken by sealing the outer periphery with an O-ring. The valve body 12 is made of a non-metallic material having a small sliding resistance (frictional force) with the rod 13, for example, a resin such as a fluororesin, and graphite.

  A second opening 21 through which fluid flows is formed in the side wall of the valve body 12. Therefore, the second opening 21 penetrates the side wall of the valve body 12 and communicates the inner peripheral surface side and the outer peripheral surface side of the valve body 12. The valve body 12 has an end that is open in the valve opening direction Z1, and fuel is supplied to the opening from the feed pump. The second opening 21 and the first opening 20 communicate with each other so that fuel flows between the inner peripheral surface side of the valve body 12 and the outer peripheral surface side of the housing 11. The second opening 21 is formed at the bottom of an annular groove formed in the outer peripheral surface of the valve body 12. Therefore, the 1st opening part 20 and the 2nd opening part 21 are connected by positioning the 1st opening part 20 so that an annular groove may be opposed. Further, for example, the second opening 21 and the first opening 20 may be arranged so as to directly overlap without providing an annular groove. Since the valve body 12 is fixed in the housing 11, the fuel flowing down from the second opening 21 toward the housing 11 always flows down through the first opening 20.

  Next, the rod 13 will be described. The rod 13 is a single rod-shaped member, and is disposed on the inner peripheral side (the inner peripheral surface side) of the housing 11 so as to extend in the axial direction Z. The rod 13 is accommodated in the housing 11 so as to be capable of reciprocating in the axial direction Z. The opening end 22 of the rod 13 positioned in the valve opening direction Z1 is formed with a passage space 23 that opens in the opening end 22 and extends in the valve closing direction Z2 and through which fuel flows. The passage space 23 may have a shape penetrating from one end to the other end as long as it extends in the axial direction Z of the rod 13. In the present embodiment, the opening end 22 side of the rod 13 It is formed in a bottomed cylindrical shape having a passage space 23. The end of the passage space 23 located in the valve closing direction Z2, that is, the bottom portion of the passage space 23 is provided closer to the valve closing direction Z2 than the end of the valve body 12 located in the valve closing direction Z2. Further, the bottom portion of the passage space 23 is located between the valve body 12 and a movable core 28 described later with respect to the axial direction Z.

  The open end 22 of the rod 13 is supported by the valve body 12. Specifically, the opening end 22 of the rod 13 is located closer to the valve opening direction Z1 than the second opening 21 and is closer to the valve closing direction Z2 than the end of the valve body 12 located in the valve opening direction Z1. Located in. Therefore, the passage space 23 is connected to the inner peripheral surface side of the valve body 12 through an opening located in the valve opening direction Z1.

  The rod 13 is formed with a third opening 24 and a fourth opening 25 that communicate the passage space 23 with the outside of the rod 13 (outer peripheral surface side). In other words, the third opening 24 and the fourth opening 25 are formed by penetrating the side wall of the rod 13 forming the passage space 23 in the radial direction. Such a rod 13 is formed by machining one rod-shaped material.

  The third opening 24 is formed in a portion located inward of the valve body 12 regardless of the reciprocal displacement of the rod 13. The third opening 24 is located closer to the valve closing direction Z2 than the second opening 21 and located closer to the valve opening direction Z1 than the end of the valve body 12 located in the valve closing direction Z2. The rod 13 is reciprocated in the axial direction Z to change the relative position between the third opening 24 and the second opening 21. Thereby, the opening degree (opening area) of the third opening 24 with respect to the second opening 21 is adjusted.

  The fourth opening 25 is formed in a portion not positioned inward of the valve body 12 regardless of the reciprocal displacement of the rod 13. The 4th opening part 25 is located in the valve closing direction Z2 side rather than the edge part of the valve body 12 located in the valve closing direction Z2. The fourth opening 25 is located between the valve body 12 and a movable core 28 described later.

  Next, the bearing 14 will be described. The bearing 14 supports the other end of the rod 13 so that the rod 13 can reciprocate. The bearing 14 is fixed to the inner peripheral surface portion side of the housing 11. Therefore, the bearing 14 supports the closed end portion 26 of the rod 13 located in the valve closing direction Z2. Such a bearing 14 is made of a material having a small sliding resistance with the rod 13 like the valve body 12, and is made of, for example, a resin such as a fluororesin and graphite. As a result, the rod 13 is supported by the valve body 12 so that one end is slidable and the other end is slidably supported by the bearing 14. Further, the bearing 14 is formed with a longitudinal groove (not shown) extending in the axial direction Z on the outer peripheral surface portion, so that the volume of the surrounding space at the other end of the rod 13 is changed according to the displacement of the rod 13 in the axial direction Z. It is configured to allow the accompanying fuel to breathe.

  Next, the drive unit 15 that drives the rod 13 will be described. The drive unit 15 drives the rod 13 along the axial direction Z. The drive unit 15 includes a coil device 27, a movable core 28, a connector 29, a spring 30 and a washer 31.

  First, the coil device 27 will be described. The coil device 27 is a device that generates a magnetic force when energized. The coil device 27 includes a yoke 32, a coil 33, and a terminal 34. The yoke 32 is formed of a cylindrical magnetic body. The yoke 32 is located on the outer peripheral side of the coil device 27.

  The coil 33 generates a magnetic force toward the valve body 12 in the movable core 28 when energized. The coil 33 is provided on the inner peripheral side of the yoke 32. The coil 33 has a cylindrical shape, and the housing 11 is disposed in the inner space thereof.

  The terminal 34 has conductivity and is electrically connected to the coil 33. The terminal 34 is pulled out to the connector 29. The terminal 34 is electrically connected to an external electric circuit (not shown) attached to the connector 29, and the energization state of the coil 33 is controlled by the external electric circuit.

  Next, the movable core 28 will be described. The movable core 28 is fixed to the outer peripheral surface portion of the rod 13 by press fitting, welding, or the like. The movable core 28 is provided at a position spaced apart from the valve body 12 and the bearing 14 in the axial direction Z. In other words, the movable core 28 is provided at an intermediate portion excluding one end and the other end of the rod 13. The movable core 28 is installed on the inner peripheral side of the housing 11 so as to be capable of reciprocating in the axial direction Z. Therefore, the movable core 28 is reciprocally displaced in the axial direction Z together with the rod 13. The movable core 28 is formed in a cylindrical shape from a magnetic material such as iron.

  The upper end surface portion 35 of the movable core 28 located in the valve opening direction Z1 is arranged at a position where the nonmagnetic portion 18 exists in the axial direction Z. In other words, with respect to the axial direction Z, the end portion of the nonmagnetic portion 18 positioned in the valve opening direction Z1 is positioned more in the valve opening direction Z1 than the upper end surface portion 35 of the movable core 28, and is positioned in the valve closing direction Z2. The end portion of the portion 18 is located in the valve opening direction Z1 with respect to the axial direction Z rather than the lower end surface portion 36 of the movable core 28. Further, the upper end surface portion 35 of the movable core 28 is formed in a tapered shape. Further, the lower end surface portion 36 of the movable core 28 located in the valve closing direction Z2 is arranged at a position where the second magnetic portion 17 exists with respect to the axial direction Z.

  Since the coil device 27 is configured in this way, the magnetic flux generated by the electromagnetic force generated by energizing the coil 33 is the yoke 32, the first magnetic part 16, the movable core 28, the second magnetic part 17, the yoke 32, and the first again. A magnetic circuit that flows in the order of the magnetic part 16 is configured.

  Next, the washer 31 will be described. The washer 31 functions as a regulating member that regulates the displacement of the movable core 28 in the valve closing direction Z2. The washer 31 is annular. The washer 31 is provided in the housing 11 so that the rod 13 can be inserted therethrough. The washer 31 is provided at a position where the lower end surface portion 36 of the movable core 28 faces. Therefore, when the movable core 28 is displaced in the valve closing direction Z2, it contacts the washer 31. When the movable core 28 comes into contact with the washer 31 and the washer 31 comes into contact with the inner peripheral surface portion of the housing 11, the washer 31 restricts further displacement in the valve closing direction Z2.

  Next, the spring 30 will be described. The spring 30 is disposed between the inner wall of the housing 11 and the outer peripheral surface portion of the rod 13 and is disposed in the rod outer space 37 where the movable core 28 and the valve body 12 face each other. One end of the spring 30 is in contact with the valve body 12, and the other end is in contact with the movable core 28. The spring 30 has a force that extends in the axial direction Z. Therefore, the rod 13 is pressed by the spring 30 in the valve closing direction Z2. In other words, the spring 30 presses the rod 13 in a direction away from the valve body 12. As described above, the valve body 12 is press-fitted to the inner peripheral side of the housing 11. Thereby, the load of the spring 30 is adjusted by adjusting the press-fitting amount of the valve body 12.

  Next, control of the position of the rod 13 will be described. The amount of movement of the rod 13, that is, the position of the rod 13 with respect to the valve body 12 is determined by the balance between the urging force of the spring 30 and the attractive force of the coil device 27. The rod 13 stops at a position where the biasing force and the suction force are balanced, and remains at that position. The attraction force changes according to the magnitude of the current applied to the coil 33. Therefore, the magnitude of the current applied to the coil 33 and the amount of movement of the rod 13 are proportional.

  The current applied to the coil 33 is controlled to be a control signal (current) corresponding to the pumping amount of the high-pressure fuel pump. The pumping amount of the high-pressure fuel pump is controlled so that the fuel pressure inside the common rail becomes an optimum value set based on the load and the rotational speed.

  Next, the flow of fuel will be described. The feed pump supplies fuel from the fuel tank to the flow control solenoid valve 10. The fuel supplied from the feed pump flows from the opening portion of the valve body 12. The inflowing fuel flows down in the valve body 12 to the rod 13 side (right side in FIG. 1). The fuel that has flowed into the valve body 12 flows into the passage space 23 of the rod 13.

  When the current value applied to the coil 33 is 0, that is, when the coil 33 is not energized, the rod 13 is pressed in the valve closing direction Z2 by the urging force of the spring 30. The movement of the rod 13 in the valve closing direction Z2 is restricted by the lower end surface portion 36 of the movable core 28 coming into contact with the washer 31, and the rod 13 and the movable core 28 are located at the position where the movable core 28 and the washer 31 are in contact. Stop. The position of the rod 13 at this time becomes the reference position, and the amount of movement of the rod 13 is zero. In this case, the opening area of the third opening 24 with respect to the second opening 21 is zero. That is, the third opening 24 is in a state of being blocked by the inner peripheral surface portion of the valve body 12.

  When a current is applied to the coil 33, the movable core 28 is attracted in the valve opening direction Z1 by the magnetic field generated in the coil 33. Then, the rod 13 moves together with the movable core 28 from the reference position in the valve opening direction Z1. At this time, the rod 13 moves in a direction in which the spring 30 is compressed. The amount of movement of the movable core 28 and the rod 13 is proportional to the current value applied to the coil 33 as described above.

  As the rod 13 moves in the valve opening direction Z1, the third opening 24 (port) formed in the rod 13 and the second opening 21 of the valve body 12 overlap each other. As a result, the third opening 24 and the second opening 21 communicate with each other, and the fuel in the passage space 23 of the rod 13 sequentially passes through the third opening 24, the second opening 21, and the first opening 20. Via, it flows out of the housing 11. The area where the third opening 24 and the second opening 21 communicate (the area of the overlapping portion, that is, the opening area) changes as the rod 13 moves. That is, the area in which the third opening 24 and the second opening 21 communicate with each other varies depending on the change in the current value applied to the coil 33.

  By changing the area where the third opening 24 and the second opening 21 communicate with each other, the flow rate of the fuel flowing out from the passage space 23 to the outside of the housing 11 changes, and the flow rate of the fuel supplied to the high pressure fuel pump Is controlled.

  Next, focusing on the fourth opening 25, the fuel flow will be described. Since the distance between the valve body 12 and the movable core 28 is reduced by the movement of the rod 13 in the valve opening direction Z <b> 1, the fuel existing in the rod outer space 37 surrounded by the valve body 12, the housing 11 and the movable core 28. However, such fuel flows into the passage space 23 from the fourth opening 25 of the rod 13. Therefore, the fuel in the rod outer space 37 is prevented from obstructing the displacement of the movable core 28 in the valve opening direction Z1.

  Further, since the distance between the valve body 12 and the movable core 28 is increased by the movement of the rod 13 in the valve closing direction Z2, negative pressure is applied to the rod outer space 37 surrounded by the valve body 12, the housing 11 and the movable core 28. In this case, the fuel flows from the fourth opening 25 of the rod 13 into the rod outer space 37. Therefore, as described above, the fuel in the rod outer space 37 is prevented from obstructing the displacement of the movable core 28 in the valve closing direction Z2.

  Thus, the fuel that has flowed out of the housing 11 is supplied to the pressurizing chamber of the high-pressure fuel pump. The fuel supplied to the pressurizing chamber is pressurized, and when the pressure in the pressurizing chamber reaches a predetermined pressure, the pressurized fuel is discharged to the common rail and held in a pressure accumulation state on the common rail. Thereafter, fuel that has been subjected to stock pressure is injected into each cylinder of the engine at a predetermined time from an injector provided on the common rail.

  As described above, the passage space 23 through which the fuel flows is formed in the rod 13 of the flow control solenoid valve 10 of the present embodiment. Further, since the rod 13 is formed with a third opening 24 that communicates the passage space 23 and the outer peripheral surface side of the rod 13, the fuel that has flowed down the passage space 23 flows from the third opening 24 to the outer periphery of the rod 13. It flows down to the surface side. Such a rod 13 is provided so as to reciprocate in the housing 11, and its position in the housing 11 is controlled by an electromagnetic force generated by energizing the coil 33 and a spring force.

  The housing 11 is provided with a valve body 12 that slidably supports the rod 13. The housing 11 and the valve body 12 are formed with a first opening 20 and a second opening 21 through which fuel flows, respectively. Therefore, by controlling the relative position (opening degree) between the second opening 21 and the third opening 24, the fuel that has flowed down the passage space 23 of the rod 13 becomes the third opening 24, the second opening 21, The flow rate flowing down to the outside of the housing 11 through the first opening 20 can be controlled.

  Therefore, the function of two parts, that is, the rod integrated with the movable core in the prior art and the valve for controlling the opening area can be realized by one part called the rod 13. As a result, the number of parts can be reduced as compared with the prior art, and the manufacturing cost can be reduced.

  Further, in the present embodiment, the valve body 12 is made of a metal material having a small sliding resistance with the rod 13, so that the sliding resistance can be reduced. This reduces the change in sliding resistance with time. In other words, the sliding resistance can be made substantially constant. Therefore, it can suppress that the positioning accuracy of the rod 13 becomes low due to the change of the sliding resistance. Thereby, the controllability of the opening degree of the third opening 24 can be maintained.

  Further, in the present embodiment, one end of the rod 13 is slidably supported by the valve body 12, and the other end of the rod 13 is slidably supported by the bearing 14, so that both ends of the rod 13 are supported. It is a holding structure. By supporting not only one end but also both ends of the rod 13 in this way, when the rod 13 is reciprocally displaced, the displacement of the rod 13 in a direction crossing the reciprocating direction of the rod 13 (for example, the radial direction of the rod 13). Can be suppressed. Thereby, the continuity of the reciprocating displacement of the rod 13 can be ensured.

  Further, in the present embodiment, the outer peripheral surface portion of the valve body 12 is in contact with the inner peripheral surface portion of the housing 11, so that the fuel flowing down the first opening 20 and the second opening 21 is separated from the outer peripheral surface of the valve body 12. Flowing down between the inner peripheral surface portion of the housing 11 can be suppressed. As a result, the fuel can be prevented from leaking out of the housing 11 undesirably. Further, since the valve body 12 and the housing 11 have simple shapes, the processing can be simplified. This can further reduce the manufacturing cost.

  In the present embodiment, since one end of the spring 30 contacts the movable core 28 and the other end contacts the valve body 12, it is not necessary to newly provide a receiving member for receiving one end of the spring 30. As a result, the manufacturing cost of the receiving member can be reduced. Moreover, since it is not necessary to provide a receiving member in the housing 11, the flow control solenoid valve 10 can be reduced in size.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a flow control electromagnetic valve 10A of the second embodiment. The flow control solenoid valve 10A of the present embodiment is characterized in that a filter is provided in a portion where fuel flows.

  When the fuel passes, the filter 38 removes foreign matters contained in the passed fuel. The filter 38 is provided in the opening portion of the inner peripheral surface portion of the valve body 12. Therefore, when fuel is supplied from the feed pump to the flow control electromagnetic valve 10A, it flows into the valve body 12 through the filter 38. Therefore, the fuel from which the foreign matter has been removed flows into the passage space 23 of the rod 13.

  Thus, since the fuel from which the foreign matter has been removed is supplied from the flow control solenoid valve 10 to the injector via the high-pressure fuel pump and the common rail, it is possible to suppress a decrease in robustness due to the foreign matter in the injector. Therefore, the stable injection characteristic of the injector can be realized.

  Further, as described in the first embodiment, one end of the spring 30 is in contact with the movable core 28 and the other end is in contact with the valve body 12, so there is no need to provide a receiving member for the spring 30. If so, the filter 38 can be provided in the space occupied by the receiving member. Thus, by providing the filter 38, the flow control electromagnetic valve 10A can be prevented from increasing in size.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the first embodiment described above, the flow control electromagnetic valve 10 in which the third opening 24 and the second opening 21 communicate with each other by applying a current to the driving unit 15 has been described. The flow control electromagnetic valve 10 may be configured such that communication between the third opening 24 and the second opening 21 is blocked by applying a current to the drive unit 15.

  In the first embodiment described above, the fuel that has flowed out of the housing 11 from the first opening 20 is configured to be supplied to the high-pressure fuel pump. However, the present invention is not limited to such a configuration in the flow direction. The fuel flow direction may be reversed, that is, the fuel that flows into the passage space 23 from the outside of the housing 11 through the first opening 20 may be supplied to the high-pressure fuel pump.

  In the first embodiment described above, the flow control solenoid valve 10 has been described for use in a common rail fuel injection system. However, the present invention is not limited to such a use, and other uses for controlling the flow rate of fuel include, for example, You may apply to the structure which supplies fuel to a gasoline engine.

  In the first embodiment described above, the fluid whose flow rate is to be controlled is fuel. However, the fluid is not limited to fuel, and may be other fluid, for example, water.

DESCRIPTION OF SYMBOLS 10,10A ... Flow control solenoid valve 11 ... Housing 12 ... Valve body 13 ... Rod 14 ... Bearing 20 ... 1st opening part 21 ... 2nd opening part 23 ... Passage space 24 ... 3rd opening part 28 ... Movable core 30 ... Spring 33 ... Coil 37 ... Space outside rod 38 ... Filter

Claims (5)

A tubular housing;
A rod that extends along the axial direction of the housing and is provided so as to be reciprocally displaced toward the inner peripheral surface of the housing;
A cylindrical valve body that slidably supports one end of the rod and is fixed to an inner peripheral surface portion of the housing;
A movable core that is provided integrally with the rod at a position in the axial direction away from the valve body on the inner peripheral surface side of the housing, and reciprocally moves together with the rod;
A coil that generates a magnetic force toward the valve body in the movable core by being energized;
A spring that presses the rod in a direction away from the valve body,
The housing is formed with a first opening that communicates the inner peripheral surface side and the outer peripheral surface side of the housing,
The valve body is formed with a second opening that communicates the inner peripheral surface side and the outer peripheral surface side of the valve body,
The rod is formed with a passage space that is continuous with the inner peripheral surface portion side of the valve body and through which fluid flows, and a third opening that communicates the passage space with the outer peripheral surface portion side of the rod.
The first opening and the second opening are in communication with each other;
The movable core is formed in a cylindrical shape from a magnetic material, is provided at an intermediate portion excluding one end and the other end of the rod, is fixed to the outer peripheral surface portion of the rod, and has a diameter larger than the diameter of the rod. Have
The valve body is made of a non-metallic material having a small sliding resistance with the rod,
Further comprising a bearing provided on the inner peripheral surface portion of the housing, the bearing slidably supports the other end of the rod,
Since one end of the rod is supported by the valve body and the other end of the rod is supported by the bearing, the movable core having a large sliding area is supported by both ends of the rod without being supported by the bearing. A double-sided structure,
An opening area of the third opening with respect to the second opening is changed by reciprocating displacement of the rod. The spring is disposed between an inner peripheral surface portion of the housing and an outer peripheral surface portion of the rod, and is disposed in a space where the movable core and the valve body face each other.
One end of the spring contacts the valve body,
The flow control solenoid valve according to claim 1 , wherein the other end of the spring is in contact with the movable core. The valve body has an outer peripheral surface portion formed in a circular shape,
The housing has an inner peripheral surface formed in a circumferential shape,
The flow rate control solenoid valve according to claim 1 , wherein an outer peripheral surface portion of the valve body is in contact with an inner peripheral surface portion of the housing. The flow control electromagnetic wave according to any one of claims 1 to 3 , further comprising a filter that is provided on an inner peripheral surface side of the valve body and removes foreign matters in a fluid flowing down the valve body. valve. The passage space opens at an opening end of the rod located in the valve opening direction, and extends in the valve closing direction.
  The opening end portion side of the rod is formed in a bottomed cylindrical shape having the passage space therein, and the bottom portion of the passage space is between the valve body and the movable core in the axial direction. Position to,
  The flow rate control solenoid valve according to claim 1, wherein the bearing supports a closed end portion of the rod located in the valve closing direction.

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