JP2019109068A - Displacement detection device and flow control device using the same - Google Patents

Abstract

To provide a displacement detection device which enables increase in detection accuracy of a displacement amount of a detected member, and a flow control device using the same.SOLUTION: Reference-side magnetic portions 51, 52 of a displacement detection device 1 are formed of magnetic materials and fixed to a reference member 20. A detected-side magnetic portion 56 is formed of a magnetic material and provided so as to be able to integrally move together with a detected member 30. A magnetic flux density detection portion can detect a magnetic flux density of a magnetic circuit passing through the reference-side magnetic portions 51, 52 and the detected-side magnetic portion 56. A minimum distance variation portion 60 is provided on a detected-side outer surface 561 which is an outer surface of the detected-side magnetic portion 56. The minimum distance variation portion 60 varies a minimum distance Lmin from reference-side magnetic inner surfaces 512, 522 which are inner surfaces of the reference-side magnetic portions 51, 52 to the detected-side outer surface 561 when the detected member 30 moves.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a displacement detection device and a flow control device using the same.

  BACKGROUND Conventionally, a displacement detection device is known that can detect relative displacement of two members by a change in magnetic flux density passing through the two members. For example, Patent Document 1 describes a displacement detection device that includes a magnetic force generation unit, a magnetic circuit formation unit that forms a magnetic circuit, and a magnetic sensor that can detect a magnetic flux, and that can detect the displacement of the needle relative to the housing. There is.

JP, 2016-138851, A

  In the displacement detection device described in Patent Document 1, a magnetic circuit formation portion that forms a magnetic circuit with the needle is provided outside the housing of the fuel injection valve. Therefore, the thickness of the housing and the gap between the housing and the needle become an air gap which is one of the causes of the increase in the magnetic resistance. For this reason, when the lift amount of the needle is relatively small, the signal corresponding to the change amount of the magnetic flux with respect to the noise in the detected signal becomes small, and the lift amount may not be detected.

  The present invention has been made in view of the above-described point, and an object thereof is to provide a displacement detection device capable of improving detection accuracy of a displacement amount of a detection target member and a flow control device using the same. .

  The displacement detection device of the present invention can detect the displacement (Dm) of the detected member (30) with respect to the reference member (20). The displacement detection device includes a reference side magnetic unit (51, 52, 251, 252, 351, 352), a detection side magnetic unit (56, 356, 456), a magnetism generation unit (53, 54), a magnetic flux density detection unit 55) A nonmagnetic part (57, 58) and a minimum distance change part (60, 360, 460).

  The reference-side magnetic portion is formed of a magnetic material and is fixed to the reference member. The to-be-detected side magnetic part is formed of a magnetic material, and provided so as to be movable integrally with the to-be-detected member. The magnetism generation part is provided in the reference-side magnetic part, and can form a magnetic circuit passing through the reference-side magnetic part and the detected-side magnetic part. The magnetic flux density detection unit can detect the magnetic flux density of the magnetic circuit passing through the reference-side magnetic unit and the detected-side magnetic unit. The nonmagnetic portion is formed of a nonmagnetic material, and is connected to the reference magnetic portion or provided to face the reference magnetic portion.

  The minimum distance change portion is provided on the detected outer surface (561) which is the outer surface of the detected magnetic portion. In the minimum distance change portion, when the member to be detected moves, the minimum distance (Lmin, L1min, L2min) from the reference inner magnetic surface (512, 522) which is the inner surface of the reference magnetic portion to the outer surface to be detected is Change.

  The minimum distance change portion changes the minimum distance when the detected member moves relative to the reference member. When the minimum distance changes, the air gap of the magnetic circuit changes, and the amount of change in magnetic flux density increases. Therefore, even if the displacement of the member to be detected is minute, the amount of change in magnetic flux density can be detected. Therefore, the displacement detection device can detect a minute displacement amount of the detected member relative to the reference member.

  In addition, the flow control device of the present invention includes a reference member (20), a detected member (30), a drive unit (40), the above-described displacement detection device, a flow rate calculation unit (101), and a drive control unit (102). . The reference member has a through hole (250) through which fluid can flow. When the detected member moves relative to the reference member, fluid flows from the through hole. The drive unit can drive the detected member relative to a reference member having a through hole. The flow rate calculating unit calculates a flow rate (Q), which is the amount of fluid flowing from the through hole, based on the displacement of the detected member relative to the reference member. The drive control unit controls the drive unit based on the flow rate. The same effect as described above is obtained.

1 is a cross-sectional view of a fuel injection valve to which a displacement detection device according to a first embodiment is applied. It is the II section enlarged view of FIG. It is the III-III sectional view taken on the line of FIG. It is a schematic diagram explaining the displacement detection apparatus by 1st embodiment. It is a schematic diagram explaining the displacement detection apparatus by 1st embodiment, Comprising: It is a schematic diagram of a state different from FIG. It is a related view of valve member movement amount and magnetic flux density in a displacement detecting device by a first embodiment. It is sectional drawing of the displacement detection apparatus by 2nd embodiment. It is sectional drawing of the displacement detection apparatus by 3rd embodiment. 1 is a block diagram of a fluid control device in which a displacement detection device according to an embodiment is used. It is sectional drawing of the displacement detection apparatus by other embodiment. It is sectional drawing of the displacement detection apparatus by other embodiment. It is sectional drawing of the displacement detection apparatus by other embodiment. It is sectional drawing of the displacement detection apparatus by other embodiment.

  Hereinafter, a plurality of embodiments will be described based on the drawings. In each embodiment, substantially the same parts as those in the other embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

First Embodiment
FIG. 1 shows a cross-sectional view of a fuel injection valve 10 to which the displacement detection device 1 according to the first embodiment is applied. In FIG. 1, the valve closing direction, which is a direction in which the valve member 30 moves so as to contact the valve seat 259 along the central axis CA 30 of the injection nozzle 25 of the valve housing 20, The valve opening direction which is the direction of movement away from 259 is illustrated.

  The fuel injection valve 10 is used, for example, in a fuel injection device of a direct injection engine (not shown), and injects and supplies gasoline as a fuel to the direct injection engine. The fuel injection valve 10 includes a valve housing 20 as a “reference member”, a valve member 30 as a “detected member”, a drive unit 40, and the displacement detection device 1.

  The valve housing 20 has a first cylindrical member 21, a second cylindrical member 22, a third cylindrical member 23, a fourth cylindrical member 24, and an injection nozzle 25. The first cylindrical member 21, the second cylindrical member 22, the third cylindrical member 23 and the fourth cylindrical member 24 are all substantially cylindrical members, and the first cylindrical member 21, the second cylindrical member 22, the third It arrange | positions so that it may become coaxial in order of the cylinder member 23 and the 4th cylinder member 24. As shown in FIG.

  The first cylinder member 21 is located on the fuel injection valve 10 on the side of the combustion chamber of the direct injection engine. An injection nozzle 25 is provided at an end of the first cylindrical member 21 in the valve closing direction. A displacement detection device 1 is provided at an end of the first cylindrical member 21 in the valve opening direction.

  The second cylindrical member 22 is provided on the valve opening direction side of the displacement detection device 1. The displacement detection device 1 is located between the first cylindrical member 21 and the second cylindrical member 22. The second cylindrical member 22 is formed of a magnetic material.

  The third cylindrical member 23 is provided on the valve opening direction side of the second cylindrical member 22 so as to be connected to the second cylindrical member 22. The third cylindrical member 23 is formed of a nonmagnetic material.

  The fourth cylindrical member 24 is provided on the valve opening direction side of the third cylindrical member 23 so as to be connected to the third cylindrical member 23. The fourth cylindrical member 24 is formed of a magnetic material.

  The injection nozzle 25 is provided at an end of the first cylindrical member 21 in the valve closing direction. The injection nozzle 25 is a bottomed cylindrical member and is welded to the first cylindrical member 21. The injection nozzle 25 is subjected to a hardening treatment so as to have a predetermined hardness. The injection nozzle 25 has a plurality of injection holes 250 as “through holes” that communicate the inside and the outside of the valve housing 20. Around the injection hole 250, a valve seat 259 capable of contacting the valve member 30 is formed. Fluid can flow through the injection hole 250.

  The valve member 30 is accommodated in the valve housing 20 so as to be reciprocally movable. The valve member 30 has a shaft portion 31, a seal portion 32, an engagement portion 33, and a sliding portion 34.

  The shaft portion 31 is a bar-like portion located inside the first cylindrical member 21 and the second cylindrical member 22. The shaft portion 31 has a passage 310 having an opening at an end opposite to the side where the seal portion 32 is provided, and a hole 311 communicating the seal side of the passage 310 with the outside of the shaft portion 31.

  The seal portion 32 is provided at an end of the shaft portion 31 on the valve seat 259 side so as to be in contact with the valve seat 259. When the seal portion 32 and the valve seat 259 come into contact with each other, the flow of fuel between the inside and the outside of the valve housing 20 through the injection hole 250 is restricted. Further, when the seal portion 32 and the valve seat 259 are separated, the flow of fuel between the inside and the outside of the valve housing 20 through the injection hole 250 is permitted.

  The engagement portion 33 is provided on the opposite side of the seal portion 32 of the shaft portion 31. The outer diameter of the engaging portion 33 is larger than the outer diameter of the shaft portion 31. An end surface 331 of the engagement portion 33 on the valve seat 259 side is formed to be able to contact the movable core 41.

  The sliding portion 34 is a substantially cylindrical portion provided at an end portion of the shaft portion 31 on the seal portion 32 side. In the sliding portion 34, a part of the outer wall 341 is chamfered. In the sliding portion 34, the unchamfered portion of the outer wall 341 can slide on the inner wall of the injection nozzle 25. Thereby, the reciprocating movement of the valve member 30 at the tip end on the valve seat 259 side is guided.

  The drive unit 40 is capable of driving the valve member 30 and is provided so as to be movable relative to the valve housing 20. The drive unit 40 further includes a movable core 41, a fixed core 42, a coil 43 and springs 44 and 45.

  The movable core 41 is a substantially cylindrical member subjected to magnetic stabilization processing. The movable core 41 is provided on the injection nozzle 25 side of the engagement portion 33 so as to be capable of reciprocating. The movable core 41 has a through hole 410 substantially at the center. The shaft portion 31 of the valve member 30 is inserted into the through hole 410.

  The fixed core 42 is a substantially cylindrical member subjected to magnetic stabilization processing. The fixed core 42 is welded to the fourth cylindrical member 24 of the valve housing 20 and is fixed to the inside of the valve housing 20.

  The coil 43 is a substantially cylindrical member, and is provided so as to surround the radially outer side of the second cylindrical member 22, the third cylindrical member 23, and the fourth cylindrical member 24. The coil 43 generates a magnetic field when power is supplied, and forms a magnetic circuit passing through the fixed core 42, the movable core 41, the second cylindrical member 22, and the fourth cylindrical member 24. As a result, a magnetic attraction force is generated between the fixed core 42 and the movable core 41, and the movable core 41 is attracted to the fixed core 42.

  One end of the spring 44 is provided to be in contact with the spring contact surface 332 of the engagement portion 33. The other end of the spring 44 is in contact with one end of an adjusting pipe 11 press-fitted and fixed to the inside of the fixed core 42. The spring 44 has an expansion and contraction force in the axial direction. As a result, the spring 44 biases the valve member 30 together with the movable core 41 in the direction of the valve seat 259 and in the valve closing direction.

  One end of the spring 45 is provided in contact with the end surface 411 of the movable core 41 in the valve closing direction. The other end of the spring 45 is in contact with the annular step surface 221 of the second cylindrical member 22. The spring 45 has an expansion and contraction force in the axial direction. Thus, the spring 45 biases the movable core 41 in the direction opposite to the valve seat 259, that is, in the valve opening direction of the valve member 30.

  In the present embodiment, the biasing force of the spring 44 is set larger than the biasing force of the spring 45. Thereby, in the state where electric power is not supplied to coil 43, seal part 32 will be in the state where valve seat 259 contacted, ie, a valve closing state.

  A substantially cylindrical fuel introduction pipe 12 is press-fit and welded to the end of the fourth cylindrical member 24 opposite to the third cylindrical member 23. A filter 13 is provided inside the fuel introduction pipe 12. The filter 13 collects foreign matter contained in the fuel flowing from the inlet 14 of the fuel introduction pipe 12.

  The radial outer sides of the fuel introduction pipe 12 and the fourth cylindrical member 24 are molded with resin. A connector 15 is provided on the mold portion. The connector 15 is insert-molded with a terminal 16 for supplying power to the coil 43. Moreover, the cylindrical holder 17 which covers the coil 43 is provided in the radial direction outer side of the coil 43. As shown in FIG.

  The fuel flowing from the inlet 14 of the fuel introduction pipe 12 flows through the inside of the fixed core 42, the inside of the adjusting pipe 11, the passage 310 of the valve member 30, and the hole 311. Further, the inflowing fuel flows through the gap between the second cylindrical member 22 and the first cylindrical member 21 and the shaft portion 31 and is led to the inside of the injection nozzle 25. The space from the inlet 14 of the fuel introduction pipe 12 to the gap between the first cylindrical member 21 and the shaft 31 is a fuel passage for introducing the fuel into the injection nozzle 25.

  The displacement detection device 1 can detect a movement displacement Dm which is a displacement of the valve member 30 with respect to the valve housing 20.

  BACKGROUND Conventionally, a displacement detection device is known that can detect relative displacement of two members by a change in magnetic flux density passing through the two members. For example, Patent Document 1 describes a displacement detection device that includes a magnetic force generation unit, a magnetic circuit formation unit that forms a magnetic circuit, and a magnetic sensor that can detect a magnetic flux, and that can detect the displacement of the needle relative to the housing. There is. In the displacement detection device described in Patent Document 1, a magnetic circuit formation portion that forms a magnetic circuit with the needle is provided outside the housing of the fuel injection valve. For this reason, the thickness of the housing and the gap between the housing and the needle become an air gap which is an increase factor of the magnetic resistance. For this reason, when the lift amount of the needle is relatively small, the signal corresponding to the change amount of the magnetic flux with respect to the noise in the detected signal becomes small, and the lift amount may not be detected. Therefore, the displacement detection device 1 can improve the detection accuracy of the displacement amount of the detection target member.

  The displacement detection device 1 is provided between the first cylindrical member 21 and the second cylindrical member 22. The displacement detection device 1 includes housing-side magnetic units 51 and 52 as a “reference-side magnetic unit”, magnets 53 and 54 as a “magnetic generation unit”, and a magnetic sensor 55 as a “magnetic flux density 検 出 detection unit”. . In addition, the displacement detection device 1 includes a valve member-side magnetic unit 56 as a “detection-side magnetic unit”, nonmagnetic units 57 and 58, and a cover 59. Furthermore, the displacement detection device 1 further includes a minimum distance change unit 60.

  As shown in FIGS. 2 and 3, the housing-side magnetic portion 51 is a member formed of a magnetic material, and the cross-sectional shape perpendicular to the central axis CA30 of the valve member 30 has a central angle of about 180 degrees. It is formed to be substantially arc-shaped. The housing-side magnetic portion 51 is provided at a position facing the shaft portion 31 or the valve member-side magnetic portion 56 on the left side in the drawing of FIG. 3. The housing-side magnetic portion 51 has an arc portion 511, a protrusion 513, and a magnetic inner surface 512 as a reference-side magnetic inner surface.

  The arc portion 511 is a substantially semicircular arc-shaped portion provided along the inner wall surface 591 of the cylindrical cover 59. The protrusion 513 is formed so as to project radially inward from the radially outer side of the valve member 30 from the arc portion 511. Further, the protruding portion 513 is formed in a concave shape such that the inner wall surface on the inner side in the radial direction of the valve member 30 conforms to the shape of the valve member magnetic portion 56.

  The magnetic inner surface 512 is an inner wall surface of the protrusion 513. Further, the magnetic inner surface 512 is provided adjacent to the valve member side magnetic portion 56. There is no other member between the magnetic inner surface 512 and the valve member magnetic portion 56 except for fluid such as fuel and air.

  The housing-side magnetic portion 52 is a member formed of a magnetic material, and as shown in FIG. 3, the cross-sectional shape perpendicular to the central axis CA30 of the valve member 30 is substantially arc-shaped with a central angle of about 180 degrees. It is formed to be The housing-side magnetic portion 52 is provided at a position facing the shaft portion 31 of the valve member 30 or the valve member-side magnetic portion 56 on the right side of the paper surface of FIG. 3. The housing-side magnetic portion 52 further includes an arc portion 521, a protrusion 523 and a magnetic inner surface 522 as a reference side magnetic inner surface.

  The arc portion 521 is a substantially semicircular arc-shaped portion provided along the inner wall surface 591 of the cover 59. The protrusion 523 is formed to project radially inward from the radially outer side of the valve member 30 from the arc portion 521. Further, the protrusion 523 is formed in a concave shape such that the inner wall surface on the inner side in the radial direction of the valve member 30 conforms to the shape of the valve member magnetic portion 56.

  The magnetic inner surface 522 is an inner wall surface of the arc portion 521. Further, the magnetic inner surface 522 is provided adjacent to the valve member-side magnetic portion 56. There is no other member between the magnetic inner surface 522 and the valve member magnetic portion 56 except for fluid such as fuel and air. The magnetic inner surfaces 512, 522 are opposed to the shaft 31. Moreover, the housing side magnetic parts 51 and 52 are integrally formed. The housing side magnetic parts 51 and 52 may be separate bodies.

  The magnet 53 is provided between the housing-side magnetic portion 51 and the housing-side magnetic portion 52. The magnet 53 is located on the upper side of the drawing of FIG. The magnet 53 can form a magnetic circuit. As shown in FIG. 3, the magnet 53 forms a magnetic circuit MC 53 passing through the housing side magnetic unit 51, the valve member side magnetic unit 56, and the housing side magnetic unit 52.

  The magnet 54 is provided between the housing-side magnetic portion 51 and the housing-side magnetic portion 52. The magnet 54 is located below the paper surface of FIG. The magnet 54 can form a magnetic circuit. As shown in FIG. 3, the magnet 54 forms a magnetic circuit MC 54 that passes through the housing side magnetic unit 51, the valve member side magnetic unit 56, and the housing side magnetic unit 52. The magnets 53 and 54 are permanent magnets, and the magnets 53 and 54 are permanent magnets, thereby eliminating the need for energy from the outside.

  The magnetic sensor 55 is provided on the housing side magnetic unit 51. In the present embodiment, the magnetic sensor 55 is provided on the housing-side magnetic portion 51 located on the upper left side of the drawing of FIG. 3. The magnetic sensor 55 is provided such that the detection surfaces 551 and 552 are in contact with the housing-side magnetic portion 51. The magnetic sensor 55 detects the magnetic flux density Φ of the magnetic circuit MC53 in the housing-side magnetic unit 51, and outputs a signal corresponding to the detected magnetic flux density Φ.

  The valve member magnetic portion 56 is provided on the shaft portion 31 so as to be able to move integrally with the valve member 30. The nonmagnetic portion 57 is a substantially annular member formed of a nonmagnetic material. The nonmagnetic portion 57 is located on the valve closing direction side of the housing side magnetic portions 51 and 52. The nonmagnetic portion 58 is a substantially annular member formed of a nonmagnetic material. The nonmagnetic portion 58 is located on the valve opening direction side of the housing side magnetic portions 51 and 52.

  The cover 59 is located radially outward of the housing side magnetic parts 51 and 52 and the nonmagnetic parts 57 and 58. The cover 59 is formed in a cylindrical shape from a nonmagnetic material, and has the same outer diameter as the first cylindrical member 21 and the second cylindrical member 22.

  As shown in FIG. 4, in the displacement detection device 1, the end surface 515, 525 perpendicular to the central axis CA30 of the valve member 30 in the valve closing direction in the direction along the central axis CA30 of the housing side magnetic portions 51, 52 A virtual plane including is set as a first virtual plane VP11. Further, a virtual plane including an end face 516, 526 on the valve opening direction side in a direction perpendicular to the central axis CA30 of the valve member 30 and along the central axis CA30 of the housing side magnetic portions 51, 52 is taken as a second virtual plane VP12. . FIG. 4 shows the state of the displacement detection device 1 when the valve member 30 is in contact with the valve seat 259.

  In the displacement detection device 1, the magnetic circuits MC53 and MC54 shown in FIG. 3 are formed between the first virtual plane VP11 and the second virtual plane VP12 shown in FIGS. Therefore, the size of the gap between the housing-side magnetic parts 51 and 52 and the valve member-side magnetic part 56 between the first virtual plane VP11 and the second virtual plane VP12 is the magnetic resistance as an air gap in the magnetic circuit. Become.

  The minimum distance change portion 60 is provided on a valve member side outer surface 561 which is the outer surface of the valve member side magnetic portion 56 as the detected side outer surface. The valve member side outer surface 561 faces the magnetic inner surface 512, 522. The shortest distance from the magnetic inner surface 512, 522 to the valve member side outer surface 561 is taken as the minimum distance Lmin. Of the infinite number of line segments connecting the magnetic inner surfaces 512, 522 and the valve member side outer surface 561, the line segment with the smallest length is taken as the minimum line segment Sm. The minimum distance Lmin is set by the minimum line segment Sm.

  The minimum distance change portion 60 is opposed to the magnetic inner surfaces 512 and 522, and is symmetrically inclined with respect to the movement direction of the valve member 30. Further, the minimum distance change portion 60 is formed such that the diameter of the valve member side magnetic portion 56 becomes smaller in the valve opening direction of the valve member 30. An end of the minimum distance changing portion 60 in the valve opening direction of the valve member 30 is referred to as a valve opening side distance changing end portion 603. The end of the minimum distance changing portion 60 in the valve closing direction of the valve member 30 is referred to as a valve closing side distance changing end 604. The first virtual plane VP <b> 11 is provided between the valve opening side distance changing end 603 and the valve closing side distance changing end 604.

  As shown in FIG. 5, when the valve member 30 moves relative to the valve housing 20, the minimum distance changing unit 60 changes the minimum distance Lmin. FIG. 5 shows the state of the displacement detection device 1 when the valve member 30 is separated from the valve seat 259. When the valve member 30 moves in the valve opening direction and the valve member magnetic portion 56 passes the first virtual plane VP11, the minimum distance Lmin decreases. The amount of movement of the valve member 30 in the valve opening direction from the initial state is referred to as a valve member movement amount Mn.

  As shown in FIG. 6, the vertical axis represents the valve member movement amount Mn, and the horizontal axis represents the detected magnetic flux density Φ. As the valve member 30 moves in the valve opening direction, the valve member moving amount Mn increases. Also, the valve member-side magnetic portion 56 passes through the first virtual plane VP11. When the valve member movement amount Mn becomes Mn1, the valve closing side distance change end portion 604 starts to pass through the first virtual plane VP11.

  When the valve member magnetic portion 56 passes through the first virtual plane VP11, the minimum distance Lmin decreases. When the minimum distance Lmin decreases, the air gap of the magnetic circuits MC53 and MC54 decreases. When the air gap of the magnetic circuits MC53 and MC54 decreases, the magnetic resistance in the magnetic circuits MC53 and MC54 decreases. For this reason, the magnetic flux density 大 き く is increased. When the valve member movement amount Mn becomes larger than Mn1, the minimum distance Lmin does not change. When the minimum distance Lmin does not change, the air gap of the magnetic circuits MC53 and MC54 does not change, so the magnetic flux density Φ becomes constant.

(A) In the displacement detection device 1, when the valve member 30 moves relative to the valve housing 20, the minimum distance change unit 60 changes the minimum distance Lmin. When the minimum distance Lmin changes, the air gap of the magnetic circuits MC53 and MC54 changes. When the air gap changes, the amount of change in the magnetic flux density 大 き く increases. Therefore, even if the displacement of the valve member 30 is minute, the amount of change of the magnetic flux density Φ can be detected. Therefore, the displacement detection device 1 can detect a minute displacement amount of the valve member 30 with respect to the valve housing 20.

(B) Further, the displacement detection device 1 can detect a minute displacement amount of the valve member 30 with respect to the valve housing 20. For this reason, it is not necessary to make the magnetic sensor 55 and the housing side magnetic parts 51 and 52 larger. Thereby, the displacement detection device 1 can be miniaturized.

(C) In the displacement detection device 1, the nonmagnetic portions 57 and 58 formed of nonmagnetic material are located on the valve closing direction side and the valve opening direction side of the housing side magnetic portions 51 and 52. As a result, the magnetic circuit is less likely to be formed in the region except between the first virtual plane VP11 and the second virtual plane VP12. Therefore, it is possible to prevent the bypass of the magnetic flux. Therefore, the detection accuracy of the displacement of the valve member 30 with respect to the valve housing 20 can be further improved.

(D) In the displacement detection device 1, the housing-side magnetic portions 51, 52 are formed such that the cross-sectional shape perpendicular to the central axis CA30 of the valve member 30 is an arc having a central angle of about 180 degrees. There is. Thus, the housing-side magnetic portions 51 and 52 are provided on the entire radially outer periphery of the valve member 30. Therefore, minute displacement of the valve member 30 can be reliably detected. Therefore, the detection accuracy of the displacement of the valve member 30 with respect to the valve housing 20 can be further improved.

(E) Further, the protrusions 513 and 523 of the housing side magnetic portions 51 and 52 and the valve member side magnetic portion 56 are provided adjacent to each other. Here, “adjacent” means that there is a gap between the protrusions 513 and 523 and the valve member-side magnetic portion 56 through which fuel or air can flow, but there is no member other than the fluid. As a result, the air gap of the magnetic circuit passing through the housing-side magnetic portions 51 and 52 and the valve member-side magnetic portion 56 becomes relatively small, so noise against the signal detected even if the displacement of the valve member 30 is minute The signal corresponding to the change amount of the magnetic flux density becomes large. Therefore, the displacement detection device 1 can reliably detect a minute displacement amount of the valve member 30 with respect to the valve housing 20.

Second Embodiment
The second embodiment is the same as the first embodiment except that the form of the housing-side magnetic part, and the valve-member-side magnetic part and the minimum distance change part are provided in plural.

  As shown in FIG. 7, the housing-side magnetic parts 251 and 252 of the displacement detection device 2 according to the second embodiment have the valve-opening-side magnetic convex part 253 and the valve-closing-side magnetic convex part 254 on the nonmagnetic parts 57 and 58 side. Have. Further, the displacement detection device 2 includes a first valve member-side magnetic unit 261, a second valve member-side magnetic unit 262, a first minimum distance change unit 263, and a second minimum distance change unit 264.

  The valve-opening side magnetic convex portion 253 and the valve-closing side magnetic convex portion 254 are formed so as to extend inward from the outside of the valve housing 20. The valve-opening magnetic convex portion 253 has a first end 255 on the valve-opening direction side of the valve member 30 and a second end 256 on the valve-closing direction side of the valve member 30. The valve-closing magnetic convex portion 254 has a third end 257 on the valve opening side and a fourth end 258 on the valve closing side. In the initial state, the first end 255 is provided on the first virtual plane VP11. The fourth end 258 is provided on the second virtual plane VP12.

  The first valve member-side magnetic portion 261 is provided on the valve opening direction side of the valve member 30. The second valve member side magnetic portion 262 is provided on the valve closing direction side of the valve member 30. The first minimum distance changing portion 263 and the second minimum distance changing portion 264 are symmetrically inclined with respect to the moving direction of the valve member 30 as in the first embodiment.

  The first minimum distance changing portion 263 is provided on the side surface of the first valve member side magnetic portion 261. Further, the first minimum distance changing portion 263 has a first valve opening side distance changing end portion 631 and a second valve closing side distance changing end portion 632. The second minimum distance change portion 264 is provided on the side surface of the second valve member side magnetic portion 262. Further, the second minimum distance change unit 264 has a third valve opening side distance change end 633 and a fourth valve closing side distance change end 634.

  In the initial state, the first valve opening side distance change end portion 631 is provided between the first end 255 and the second end 256. The second valve closing side distance change end portion 632 is provided between the second end 256 and the third end 257. The third valve opening side distance change end 633 is provided between the third end 257 and the fourth end 258. The fourth valve closing distance changing end portion 634 is provided closer to the valve closing direction of the valve member 30 than the fourth end 258.

  The shortest distance from the magnetic inner surfaces 512, 522 to the side surface of the first valve member magnetic portion 261 is taken as a first minimum distance L1 min. When the valve member 30 moves relative to the valve housing 20, the first minimum distance changing portion 263 changes the first minimum distance L1 min. The shortest distance from the magnetic inner surfaces 512, 522 to the side surface of the second valve member magnetic portion 262 is taken as a second minimum distance L2min. When the valve member 30 is moved with respect to the valve housing 20, the second minimum distance changing portion 264 changes the second minimum distance L2min.

  Also in the second embodiment, the same effects as in the first embodiment can be obtained. Furthermore, the displacement detection device 2 includes a first minimum distance change unit 263 and a second minimum distance change unit 264 as the plurality of minimum distance change units 60. When a plurality of minimum distance change portions 60 are provided, when the valve member 30 moves relative to the valve housing 20, the air gap changes according to the number of the minimum distance change portions 60, and the change amount of the magnetic flux density がIt gets bigger. Therefore, it becomes easy to detect a minute displacement amount of the valve member 30 with respect to the valve housing 20.

Third Embodiment
The third embodiment is the same as the first embodiment except that the configurations of the housing-side magnetic portion, the valve member-side magnetic portion, and the minimum distance change portion are different.

  As shown in FIG. 8, the housing-side magnetic portions 351 and 352 of the displacement detection device 3 are provided on the valve opening direction side and the valve closing direction side of the valve member 30 while the magnetic inner surfaces 512 and 522 face the valve member 30. It is done. The valve member-side magnetic portion 356 is formed so that the cross section in the axial direction of the valve member 30 has a stepped shape, and has a step surface 357 on the side surface. The minimum distance change portion 360 is formed on the side surface of the valve member side magnetic portion 356. In addition, the minimum distance change portion 60 is formed such that the diameter of the valve member-side magnetic portion 356 decreases in the valve opening direction of the valve member 30. Also in the third embodiment, the same effects as in the first embodiment can be obtained.

Fourth Embodiment
The displacement detection device 4 of the fourth embodiment is used for the flow control device 100. The configuration of the displacement detection device 4 of the fourth embodiment is the same as the configuration of the displacement detection device 1 of the first embodiment.

As shown in FIG. 9, the flow control device 100 includes a displacement detection device 4, a flow calculation unit 101, and a drive control unit 102.
The displacement detection device 4 detects the movement displacement Dm. The detected movement displacement Dm is output to the flow rate calculation unit 101. The flow rate calculation unit 101 calculates a flow rate Q, which is the amount of fluid flowing from the injection hole 250, based on the movement displacement Dm detected by the displacement detection device 4. The calculated flow rate Q is output to the drive control unit 102. The drive control unit 102 performs feedback control of the drive unit 40 based on the flow rate Q. As described above, even when the displacement detection device 4 is used in the flow control device 100, the same effects as in the first embodiment can be obtained.

(Other embodiments)
In the above embodiment, the displacement detection device detects the displacement of the valve member with respect to the nozzle body in the fuel injection valve. However, the field to which the displacement detection device is applied is not limited to this. Further, in the above-described embodiment, the nonmagnetic member is positioned to sandwich the housing side magnetic portion. However, the position at which the nonmagnetic member is provided is not limited to this. Furthermore, in the above-described embodiment, the magnetic flux sensor capable of detecting the magnitude of the magnetic flux density of the magnetic circuit is provided as the “magnetic flux density detection unit”. However, the “magnetic flux density detection unit” is not limited to this. Moreover, in the above-mentioned embodiment, a magnet may be an electromagnet.

As shown in FIG. 10, in the first embodiment, the valve opening side distance changing end portion 603 may be provided on the first virtual plane VP11.
As shown in FIG. 11, in the first embodiment, the valve member-side magnetic unit 56 may be provided on the second virtual plane VP12. At this time, the minimum distance change portion 60 is symmetrically inclined so that the diameter of the valve member side magnetic portion 56 becomes larger in the valve opening direction of the valve member 30. The valve opening side distance change end portion 603 is provided closer to the valve opening direction of the valve member 30 than the second virtual plane VP12. The valve opening side distance change end 603 may be provided on the second virtual plane VP12.

  As shown in FIG. 12, the valve member-side magnetic portion 556 has a plurality of groove portions 557. The groove portion 557 is formed to extend in the axial direction of the valve member 30, and is formed to increase in the valve opening direction of the valve member 30.

  As shown in FIG. 13, the housing side magnetic parts 51 and 52 may have a shape in which a part is cut away from a cylindrical shape. Moreover, the magnet 53 may be one. Furthermore, the valve housing 20 may have a notch 211. The first cylindrical member 21 and the second cylindrical member 22 are connected by a portion 212 of the first cylindrical member 21 which is not cut out. The notch 211 makes it easy to assemble the displacement detection device 1 into the fuel injection valve 10. Therefore, the fuel injection valve 10 capable of detecting the displacement of the valve member 30 relatively easily can be manufactured.

  As mentioned above, this invention is not limited to such embodiment, In the range which does not deviate from the meaning, it can implement with various forms.

1, 2, 3, 4 ... displacement detection device,
20: Valve housing (reference member),
30 ... valve member (detected member),
51, 52, 251, 252, 351, 352 ... housing side magnetic part (reference side magnetic part),
512, 522 ··· Magnetic inner surface (reference side magnetic inner surface),
53, 54 ··· Magnetic generation unit, 55 · · · Magnetic flux density detection unit,
56, 356, 456 ... to be detected magnetic part,
561 ····· Valve member side outer surface (detected side outer surface),
60, 360, 460 ... minimum distance change part.

Claims (6)

A displacement detection device capable of detecting displacement (Dm) of a detected member (30) with respect to a reference member (20),
Reference-side magnetic portions (51, 52, 251, 252, 351, 352) formed of a magnetic material and fixed to the reference member;
To-be-detected side magnetic parts (56, 356, 456) which are formed of a magnetic material and provided so as to be movable integrally with the to-be-detected member;
A magnetism generation portion (53, 54) provided in the reference side magnetic portion and capable of forming a magnetic circuit passing through the reference side magnetic portion and the detected side magnetic portion;
A magnetic flux density detection unit (55) capable of detecting a magnetic flux density of a magnetic circuit passing through the reference side magnetic unit and the detected magnetic unit;
A nonmagnetic portion (57, 58) formed of a nonmagnetic material and connected to the reference side magnetic portion or provided to face the reference side magnetic portion;
A reference side magnetic inner surface (512, 522) which is provided on the outer surface (561) to be detected which is the outer surface of the magnetic portion to be detected and which is the inner surface of the reference magnetic portion when the member to be detected moves. A minimum distance change portion (60, 360, 460) in which the minimum distance (Lmin, L1min, L2min) from the sensor to the outer surface on the detected side changes;
A displacement detection device comprising:   The displacement detection device according to claim 1, wherein the minimum distance change unit is opposed to the reference-side inner magnetic surface, and is inclined with respect to the movement direction of the detection target member.   The displacement detection device according to claim 1, wherein a plurality of the minimum distance change units are provided.   The displacement detection device according to any one of claims 1 to 3, wherein the magnetism generation unit is a magnet or an electromagnet. A reference member (20) having a through hole (250) through which fluid can flow;
A detected member (30) in which fluid flows from the through hole when it moves relative to the reference member;
A drive unit (40) capable of driving the detected member relative to the reference member;
Displacement detection devices (1, 2, 3, 4) capable of detecting displacement (Dm) of the detected member relative to the reference member;
A flow rate calculating unit (101) for calculating a flow rate (Q), which is an amount of fluid flowing from the through hole, based on the displacement of the detected member relative to the reference member;
A drive control unit (102) that controls the drive unit based on the flow rate;
Equipped with
The displacement detection device is
Reference-side magnetic portions (51, 52, 251, 252, 351, 352) formed of a magnetic material and fixed to the reference member;
To-be-detected side magnetic parts (56, 356, 456) which are formed of a magnetic material and provided so as to be movable integrally with the to-be-detected member;
A magnetism generation portion (53, 54) provided in the reference side magnetic portion and capable of forming a magnetic circuit passing through the reference side magnetic portion and the detected side magnetic portion;
A magnetic flux density detection unit (55) capable of detecting a magnetic flux density of a magnetic circuit passing through the reference side magnetic unit and the detected magnetic unit;
A nonmagnetic portion (57, 58) formed of a nonmagnetic material and connected to the reference side magnetic portion or provided to face the reference side magnetic portion;
A reference side magnetic inner surface (512, 522) which is provided on the outer surface (561) to be detected which is the outer surface of the magnetic portion to be detected and which is the inner surface of the reference magnetic portion when the member to be detected moves. A minimum distance change portion (60, 360, 460) in which the minimum distance (Lmin, L1min, L2min) from the sensor to the outer surface on the detected side changes;
Flow control device.   The flow control device according to claim 5, wherein the fluid is a fuel.

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