JP2019049491A - Displacement detector and method for manufacturing displacement detector - Google Patents

Abstract

To improve detection accuracy of a displacement detector.SOLUTION: The present invention comprises: a rod member 22 that is displaced following motion of a spool 51; a compression coil spring 27 for urging the rod member 22 toward the spool 51; a magnet 24, arranged in the rod member 22, which is displaced together with the rod member 22; a case 12 for supporting the rod member 22 reciprocally in a direction of displacement; and a magnetism detection unit 32 for detecting a change of a magnetic field due to the displacement of the magnet 24. The case 12 is provided with a first spring receiver face for supporting one end of the compression spring coil 27, and the rod member 22 is provided with a second spring receiver face for supporting the other end of the compression spring coil 27, at least one of the first spring receiver face and the second spring receiver face being inclined faces 145, 125 inclined relative to a plane orthogonal to the direction of the displacement.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a displacement detection device and a method of manufacturing the displacement detection device.

  In Patent Document 1, a magnet attached to a displacement member displaced following a measurement object, a magnetic sensor disposed facing the magnet, and a coil spring biasing the displacement member toward the measurement object And a displacement detection device comprising In this displacement detection device, the position of the magnet changes according to the displacement of the measurement object, and the direction and the size of the magnetic flux passing through the magnetic sensor change with the change of the position of the magnet. The displacement amount of the measurement object can be specified based on

JP, 2015-10876, A

  However, if the coil spring is arranged in an inclined state with respect to the displacement direction of the displacement member due to a manufacturing error, an assembly error, etc., an error occurs in the biasing force (axial force) in the displacement direction by the coil spring. The detection accuracy of the detection device may be reduced.

  The present invention has been made in view of the above problems, and an object thereof is to improve the detection accuracy of a displacement detection device.

  According to a first aspect of the present invention, in a displacement member on which a first spring receiving surface for supporting one end of a compression coil spring is provided and a magnet is disposed, the support member supports the displacement member reciprocally in the displacement direction. A second spring receiving surface for supporting the other end of the spring is provided, and at least one of the first spring receiving surface and the second spring receiving surface is an inclined surface which is inclined with respect to a plane orthogonal to the displacement direction of the displacement member. It is a displacement detection device characterized by the above.

  In the first invention, by supporting the compression coil spring by the inclined surface, the inclination of the compression coil spring can be suppressed with respect to the displacement direction of the displacement member. Errors in axial force) can be reduced.

  A second invention is characterized in that both the first spring bearing surface and the second spring bearing surface are inclined surfaces.

  In the second aspect of the invention, since the inclined surfaces are provided on both the first and second spring receiving surfaces, both ends of the compression coil spring can be properly positioned. Thus, the positioning accuracy of the compression coil spring can be improved as compared with the case where the inclined surface is provided on one of the first spring receiving surface and the second spring receiving surface, and therefore the inclination of the compression coil spring can be suppressed more effectively.

  A third invention is characterized in that the inclined surface is an outer peripheral surface of a tapered portion which is tapered toward the inside of the compression coiled spring, and is in contact with the inner periphery of the compression coiled spring.

  In the third aspect of the invention, since the tapered portion is disposed inside the compression coil spring, the displacement detection device can be miniaturized as compared with the case where the tapered portion is disposed outside the compression coil spring.

  A fourth invention is characterized in that the magnet is disposed inside the compression coil spring.

  In the fourth invention, since the magnet is disposed inside the compression coil spring, the displacement detection device can be miniaturized as compared with the case where the magnet is disposed outside the compression coil spring. Since the compression coiled spring is properly positioned by the inclined surface, it is possible to prevent the inner circumference of the compression coiled spring from coming into contact with the outer circumference of the magnet when the displacement member reciprocates. As a result, wear of the magnet can be prevented.

  A fifth invention is characterized in that the shape of the end of the compression coil spring in contact with the inclined surface is a non-grinding closed end.

  In the fifth invention, since the shape of the end of the compression coil spring in contact with the inclined surface is a non-grinding closed end, when the shape of the end of the compression coil spring is an open end, and the ground end is ground The stability of the arrangement of the compression coil spring can be improved as compared with the case of.

  A sixth invention is characterized in that the end of the compression coil spring is in contact with the inclined surface in a range of 180 degrees or more.

  In the sixth invention, since the end of the compression coiled spring contacts the inclined surface in the range of 180 degrees or more, the arrangement of the compression coiled spring is stable compared to the case where the range in contact with the inclined surface is less than 180 degrees. I can improve the nature.

  In a seventh invention, the support member is a case having a bottomed cylindrical case main body in which the compression coil spring is accommodated, and a lid member closing the opening of the case main body, and the opening is the case main body The first spring receiving surface is provided on the distal end side of the lid member, and the tapered surface of the opening is in surface contact with the proximal end side of the lid member. A contact surface is provided.

  In the seventh invention, the positioning accuracy of the lid member with respect to the case body can be improved by bringing the tapered contact surface provided on the lid member into surface contact with the tapered surface provided on the opening of the case body. Thus, the positioning accuracy of the compression coil spring supported by the first spring receiving surface of the lid member can be improved.

  The eighth invention further comprises a fixing member for fixing the lid member to the case body, the fixing member being a magnetic shield capable of shielding the magnetism, and a pressing portion for pressing the lid member toward the inside of the case body, And a fixing portion fixed to the case main body, wherein the pressing portion covers an end face on the base end side of the lid member.

  In the eighth invention, when the lid member is fixed to the case main body, it is only necessary to insert the lid member in one direction into the opening of the case main body. Since it is not necessary to rotate the lid member, in the process of inserting the lid member into the opening, it is possible to prevent a problem such as the compression coil spring being twisted and damaged by the rotation of the lid member. Moreover, it can suppress that the magnetism of the exterior of a displacement detection apparatus influences a magnetism detection part. Furthermore, since the fixing member has a function as a magnetic shield, it is not necessary to provide a member dedicated to the magnetic shield which covers the proximal end side of the lid member separately from the fixing member. For this reason, the component parts of a displacement detection apparatus can be reduced.

  The ninth invention is a magnet mounting step of attaching a magnet to a displacement member, inserting the displacement member into the inside of the case main body from the opening, and inserting one end of the displacement member into a through hole provided in the bottom of the case main body. A member insertion step; a spring insertion step of inserting the compression coil spring into the inside of the case body from the opening and positioning the other end of the compression coil spring on the second spring receiving surface of the displacement member; Positioning the one end of the compression coil spring on the first spring receiving surface of the lid member and attaching the lid member to the case body, and the lid member attached to the case body by fixing the fixing member to the case body And a fixing step of fixing, which is a method of manufacturing a displacement detection device.

  In the ninth aspect, it is only necessary to insert the lid member in one direction into the opening of the case body. Since it is not necessary to rotate the lid member, in the process of inserting the lid member into the opening, it is possible to prevent a problem such as the compression coil spring being twisted and damaged by the rotation of the lid member. In the assembled displacement detection device, the inclined surface supporting the compression coil spring positions the central axis of the compression coil spring so as to coincide with the axial center of the through hole supporting the displacement member. Thereby, the error of the biasing force (axial force) in the displacement direction by the compression coil spring can be reduced.

  According to the present invention, the detection accuracy of the displacement detection device can be improved.

1 is a cross-sectional view of a displacement detection device and a hydraulic valve device according to a first embodiment of the present invention. It is the elements on larger scale which show the shape of the edge part of the compression coiled spring made into the non-grinding closed end. It is the elements on larger scale which show the shape of the end part of the compression coiled spring made into the grinding closed end. It is a figure shown about the flange and lid member which support the compression coiled spring of the displacement detection apparatus concerning a comparative example. It is a flowchart which shows the manufacture procedure of a displacement detection apparatus. It is sectional drawing of the displacement detection apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing of the displacement detection apparatus which concerns on the modification 1 of embodiment of this invention. It is sectional drawing of the displacement detection apparatus which concerns on the modification 2 of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First Embodiment
Below, the case where displacement detection device 100 is used as a stroke sensor which detects the amount of displacement (stroke amount) of spool (valve element) 51 of hydraulic valve device 50 is explained.

  FIG. 1 is a cross-sectional view of a displacement detection device 100 and a hydraulic valve device 50 according to a first embodiment of the present invention. As shown in FIG. 1, the hydraulic valve device 50 includes a cylindrical sleeve 52 and a spool 51 disposed in the sleeve 52 and axially reciprocated. In the hydraulic valve device 50, the hydraulic oil is supplied to and discharged from the oil chamber 53 facing the one end surface 51a of the spool 51 through the supply and discharge holes 52a provided in the sleeve 52, whereby the spool 51 is displaced in the axial direction. The displacement of the spool 51 controls the opening and closing of a port (not shown) formed in the sleeve 52. The displacement detection device 100 is attached to the end of the sleeve 52 so as to face one end surface 51 a of the spool 51.

  The displacement detection device 100 includes a rod member 22 as a displacement member which is displaced following a spool 51 which is a displacement detection target member, a magnet 24 disposed on one end side of the rod member 22 and displaced together with the rod member 22, and a rod member 22. A case 12 as a support member for supporting 22 reciprocably in the displacing direction, a compression coil spring 27 disposed in the case 12 for urging the rod member 22 toward the spool 51, and orthogonal to the displacement direction of the magnet 24 And a magnetism detection unit 32 disposed in the case 12 so as to face the magnet 24 in the direction in which

  The case 12 has a bottomed cylindrical case body 120 in which the compression coil spring 27 is accommodated, and a lid member 14 that closes the opening 12 g of the case body 120. The case body 120 and the lid member 14 are each formed of a nonmagnetic material such as brass. The case body 120 is formed inside the cylindrical portion 12a, a bottom portion 12b provided on one end side of the cylindrical portion 12a, an opening 12g provided on the other end side of the cylindrical portion 12a, and the cylindrical portion 12a. And a housing portion 12c. The housing portion 12 c houses a part of the rod member 22 in which the magnet 24 is disposed together with the magnet 24.

  In the cylindrical portion 12a, a fixing hole 12e which is opened on the outer peripheral surface of the cylindrical portion 12a and which is recessed toward the housing portion 12c is formed. The fixing hole 12 e is a non-penetrating stepped hole, and the magnetic detection unit 32 is fixed in the fixing hole 12 e.

  A support hole 12d, through which the shaft 22a of the rod member 22 is inserted, is formed through the bottom 12b of the case body 120. In the support hole 12d, bushes 18 which are bearings for slidably supporting the shaft portion 22a of the rod member 22 are provided axially at two places apart from each other. By providing the bushes 18 in two places, it is possible to suppress the inclination of the axial center of the rod member 22 supported in a cantilever manner by the case main body 120 with respect to the support axial center O which is the axial center of the support hole 12d. The bush 18 may be provided at one place, and in this case, the axial length of the case body 120 can be shortened.

  In the bottom 12 b of the case body 120, a plurality of communication holes 12 f that communicate the housing 12 c with the outside are formed around the support holes 12 d. One end of the communication hole 12f is open to the oil chamber 53 of the hydraulic valve device 50, and the hydraulic oil in the oil chamber 53 flows into the housing 12c through the communication hole 12f. That is, the accommodation portion 12c is filled with the hydraulic oil.

  The rod member 22 has a cylindrical shaft 22a slidably supported by the case body 120 via the bush 18, a hemispherical contact end 22b formed at the tip of the shaft 22a, and a shaft 22a. And a substantially disc-like flange 22c formed at the proximal end of the shaft 22a and extending outward in the radial direction of the shaft 22a.

  In the flange 22c, a cylindrical holding shaft 22d extending on the opposite side to the shaft 22a is provided coaxially with the shaft 22a. At the tip end of the holding shaft 22d, an external thread is formed on which an internal thread of a nut 26 described later is screwed. In design, the rod member 22 is supported by the case body 120 such that the central axis of the rod member 22 and the support axis O of the support hole 12d are coaxially arranged. That is, the central axis of the rod member 22 coincides with the support axis O.

  The rod member 22 is formed of a nonmagnetic material as in the case 12. Since the spool 51 abuts on the contact end 22b of the rod member 22, the rod member 22 is formed of austenitic stainless steel or the like, which is harder than brass.

  The magnet 24 is a cylindrical permanent magnet including a rare earth element such as Nd or Sm, and is disposed on the outer periphery of the holding shaft 22d so that the N pole 24a and the S pole 24b are aligned in the axial direction of the holding shaft 22d. Be placed. The magnet 24 has an insertion hole 24c through which the holding shaft 22d is inserted, and the nut 26 is attached to the tip of the holding shaft 22d protruding from the insertion hole 24c via a washer 25. Thereby, the magnet 24 is fixed to the holding shaft 22 d in a state of being held by the flange 22 c, the nut 26 and the washer 25. The nut 26 and the washer 25 are formed of a magnetic material. The nut 26 and the washer 25 are components for sandwiching the magnet 24 with the flange 22c, and are components of a displacement member which is displaced in the displacement direction following the spool 51.

  Since the magnet 24 is fixed to the rod member 22, the magnet 24 follows the spool 51 together with the rod member 22 and is displaced along the support axis O. The change in the magnetic field caused by the displacement of the magnet 24 is detected by the magnetic detection unit 32.

  The magnetic detection unit 32 is a magnetic sensor (not shown) such as a Hall element or a magnetoresistive element that outputs an output value corresponding to a change in the magnetic field caused by the displacement of the magnet 24, and an amplification circuit that processes the output value of the magnetic sensor And a processing circuit (not shown) of The magnetic detection unit 32 outputs a detection value corresponding to the displacement amount of the rod member 22 calculated based on the output value of the magnetic sensor, that is, the displacement amount (stroke amount) of the spool 51 in contact with the rod member 22.

  In the displacement detection device 100, when the rod member 22 is displaced along the support axis O, the magnet 24 is also displaced, and the direction and the magnitude of the magnetic flux passing through the magnetic detection unit 32 change. The output value of the magnetic detection unit 32 changes in accordance with the change in the direction or size of the magnetic flux passing through the magnetic detection unit 32. Therefore, the displacement detection device 100 can detect the displacement amount of the rod member 22, that is, the displacement amount of the spool 51 based on the output value of the magnetic detection unit 32.

  The magnetic detection unit 32 is mounted on the substrate 34, and is fixed to the stepped portion of the fixing hole 12e formed in the cylindrical portion 12a, thereby being assembled to the case main body 120.

  In a state where the magnetic detection unit 32 is disposed in the fixing hole 12e, the cylindrical magnetic shield 16 is assembled on the outer periphery of the cylindrical portion 12a so as to close the fixing hole 12e. The magnetic shield 16 is formed of a soft magnetic material having a small coercive force, such as an iron-based alloy capable of shielding the magnetism, and suppresses the influence of the magnetism outside the displacement detection device 100 on the magnetism detection unit 32.

  A notch (not shown) is formed in the magnetic shield 16, and a lead (not shown) for connecting a controller (not shown) for controlling the operation of the spool 51 and the magnetic detection unit 32 is wired through the notch. Ru.

  The opening 12 g of the case body 120 is closed by the lid member 14 in a state where the magnet 24 and a part of the rod member 22 to which the magnet 24 is assembled are housed in the housing portion 12 c.

  The opening 12g of the case main body 120 is a circular opening that communicates the housing 12c with the outside, and is provided continuously to the housing 12c. The opening 12 g of the case body 120 is provided with a tapered surface 12 h formed in a tapered shape whose diameter decreases from the end face of the case body 120 toward the inside of the case body 120.

  The lid member 14 has a generally frusto-conical shape having a tapered shape as a whole. The lid member 14 has a truncated cone-shaped proximal end tapered portion 14a provided on the proximal end side, a truncated cone-shaped distal end tapered portion 14c provided on the distal end side, the proximal end tapered portion 14a, and the distal end side tapered portion And 14c, and a cylindrical portion 14b having a cylindrical shape provided therebetween.

  The proximal end tapered portion 14 a is formed in a tapered shape in which the diameter decreases from the proximal end side to the distal end side of the lid member 14. The outer peripheral surface of the proximal end tapered portion 14 a is a contact surface 142 that is in surface contact with the tapered surface 12 h of the opening 12 g of the case body 120. The tapered surface 12 h and the contact surface 142 are formed such that the central axis of the truncated cone-shaped tip-side tapered portion 14 c of the lid member 14 coincides with the support axis O of the support hole 12 d for supporting the rod member 22.

  The cylindrical portion 14 b protrudes from the proximal end tapered portion 14 a toward the distal end side of the lid member 14. The distal end side tapered portion 14 c protrudes from the cylindrical portion 14 b to the distal end side of the lid member 14. The distal end side tapered portion 14 c is formed in a tapered shape in which the diameter decreases from the proximal end side to the distal end side of the lid member 14. The outer peripheral surface of the distal end side taper portion 14 c is an inclined surface 145 with which the end of the compression coil spring 27 abuts.

  The lid member 14 is fixed to the case body 120 in a state of being pressed against the fixing member 42 by assembling the fixing member 42 to the case body 120. The fixing member 42 includes a pressing portion 42 a that presses the lid member 14 toward the inside of the case main body 120, and a fixing portion 42 b that is fixed to the case main body 120. The pressing portion 42a is formed in a disk shape, and the fixing portion 42b is formed in a cylindrical shape rising from the outer periphery of the disk-shaped pressing portion 42a. On the inner peripheral surface of the fixing portion 42b, a female screw to be screwed to the male screw formed on the outer peripheral surface of the cylindrical portion 12a of the case main body 120 is formed.

  When the fixing portion 42 b is fixed to the case main body 120, the pressing portion 42 a covers and supports the base end surface 141 which is the end surface on the base end side of the lid member 14. Similar to the magnetic shield 16, the fixing member 42 is formed of a soft magnetic material having a small coercive force such as an iron-based alloy capable of shielding magnetism, and the pressing portion 42 a covers the entire one end surface of the case main body 120. That is, the fixing member 42 has a function of supporting the lid member 14 and also has a function of a magnetic shield that suppresses the influence of the magnetism outside the displacement detection device 100 on the magnetism detection unit 32.

  An annular groove 147 is provided on the outer peripheral surface 143 of the cylindrical portion 14 b. An annular O-ring 48 is mounted in the groove 147 to seal the gap between the lid member 14 and the case body 120. The O-ring 48 shuts off the communication between the inside and the outside of the housing portion 12c, and the hydraulic oil is prevented from leaking to the outside from between the lid member 14 and the case main body 120.

  The distal end side taper portion 14 c has a cross-sectional shape that is axially symmetrical with respect to the support axis O, and is inserted inside the compression coil spring 27. The distal end side taper portion 14 c is formed in a tapered shape which is tapered toward the inside of the compression coil spring 27, and the outer peripheral surface thereof is an inclined surface 145 having a linear cross section. The inclined surface 145 is inclined with respect to a virtual plane orthogonal to the displacement direction, and the inner periphery of the end of the compression coil spring 27 (radially inward of the center diameter of the coil spring) abuts on the inclined surface 145 . That is, the inclined surface 145 is a spring receiving surface provided to support one end (right end in the figure) of the compression coil spring 27 in the lid member 14 constituting the case 12.

  The diameter of the distal end of the distal end side tapered portion 14c (the diameter at which the distal end side tapered portion 14c becomes the smallest) and the diameter of the proximal end of the distal end side tapered portion 14c (the diameter at which the distal end side tapered portion 14c becomes largest) It is set to absorb the tolerance of the inner diameter of 27. In other words, the minimum diameter of the distal end side taper portion 14 c is set to be smaller than the minimum value of the inner diameter of the compression coil spring 27, and the maximum diameter of the distal end side taper portion 14 c is the maximum inner diameter of the compression coil spring 27. It is set to be larger than the value.

  By forming the inclined surface 145 in this way, even if the inner diameter of the compression coil spring 27 deviates from the design value (reference value), the deviation can be absorbed by the inclined surface 145, so the compression coil spring 27 The central axis of can be made coincident with the support axis O. For example, when the inner diameter of the compression coil spring 27 is smaller than the design value, the compression coil spring 27 is positioned at a portion on the small diameter side of the distal end side taper portion 14c. On the other hand, when the inside diameter of the compression coiled spring 27 is larger than the design value, the compression coiled spring 27 is positioned at the portion on the large diameter side of the distal end side taper portion 14c.

  A flat surface portion 144 perpendicular to the support axis O is formed between the outer edge of the inclined surface 145 (the outer circumference circle of the inclined surface 145 which is annular in plan view) and the outer edge of the cylindrical portion 14b. The compression coil spring 27 is not in contact with the flat portion 144. As shown in the figure, the end of the compression coil spring 27 supported by the lid member 14 may be in contact with only the inclined surface 145, but may be in contact with both the inclined surface 145 and the flat portion 144. Good.

  The flange 22 c of the rod member 22 has a disk-like base portion 127 and a tapered portion 128 which tapers from the base portion 127 toward the inside of the compression coil spring 27. The distal end surface 126 of the tapered portion 128 is a circular flat surface, and the end surface of the magnet 24 abuts on the distal end surface 126. The outer peripheral surface of the tapered portion 128 is an inclined surface 125 whose section is parabolic. The inclined surface 125 is inclined with respect to a virtual plane orthogonal to the displacement direction, and the inner peripheral side (radially inward of the center diameter of the coil spring) of the end of the compression coil spring 27 Contact. That is, the inclined surface 125 is a spring receiving surface provided to support the other end (left end in the drawing) of the compression coil spring 27 in the rod member 22.

  The diameter of the distal end of the tapered portion 128 (the diameter at which the tapered portion 128 becomes the smallest) and the diameter of the proximal end of the tapered portion 128 (the diameter at which the tapered portion 128 becomes the largest) can absorb the tolerance of the inner diameter of the compression coil spring 27 Is set as In other words, the minimum diameter of the taper portion 128 is set to be smaller than the minimum value of the inner diameter of the compression coil spring 27, and the maximum diameter of the taper portion 128 is larger than the maximum value of the inner diameter of the compression coil spring 27. Is set to be

  By forming the inclined surface 125 in this manner, as in the case of the above-described inclined surface 145, even if the inner diameter of the compression coil spring 27 deviates from the design value (reference value), the deviation is made by the inclined surface 125. Since absorption is possible, the central axis of the compression coil spring 27 can be made to coincide with the support axis O.

  The inclination angles of the inclined surfaces 125 and 145 with respect to the plane orthogonal to the support axis O are set in consideration of the force acting on the compression coil spring 27 from the inclined surfaces 125 and 145 and the allowable load of the compression coil spring 27. That is, the inclination angles of the inclined surfaces 125 and 145 are set so as to satisfy the condition represented by the following expression (1).

(Allowable load in the radial direction of the compression coil spring)> (axial force of the compression coil spring) × (ratio of component forces in the radial direction depending on the inclination angle of the inclined surface) (1)
A flat plane portion 124 orthogonal to the support axis O is formed between the outer edge of the inclined surface 125 (the outer circumference of the inclined surface 125 which is annular in plan view) and the outer edge of the disk-like base 127. . The compression coil spring 27 is not in contact with the flat portion 124. As shown in the figure, the end of the compression coil spring 27 supported by the flange 22c of the rod member 22 may be in contact with only the inclined surface 125, but in contact with both the inclined surface 125 and the flat portion 124. It may be

  The compression coil spring 27 is an elastic member formed of a nonmagnetic material such as austenitic stainless steel, and is assembled in a compressed state between the flange 22 c of the rod member 22 and the lid member 14. Therefore, the biasing force of the compression coil spring 27 always acts in the direction of pressing the rod member 22 against the spool 51. When the displacement detection device 100 is not assembled to the hydraulic valve device 50, the rod member 22 is pressed by the biasing force of the compression coil spring 27, and the flange 22c of the rod member 22 contacts the bottom 12b of the case body 120. It becomes.

  Since both ends of the compression coil spring 27 are supported by the flange 22 c of the rod member 22 and the lid member 14, the magnet 24 held by the holding shaft 22 d protruding from the flange 22 c toward the lid member 14 is It is placed inside.

  FIG. 2A is a partially enlarged view showing the shape of the end of the compression coil spring 27 which is a non-grinding closed end. FIG. 2B is a partially enlarged view showing the shape of the end portion of the compression coil spring 27G in the grinding closed end. FIGS. 2A and 2B schematically show the shape of the end of the compression coil spring, showing the diameter (wire diameter) of the wire of the compression coil spring larger than the actual diameter and showing the center diameter smaller than the actual diameter. ing.

  As shown in FIG. 2B, the compression coil spring 27G is arranged so that the bearing surface (surface contacting the flat spring receiving surface) 27b is flat in consideration of being disposed on the flat spring receiving surface. It is common for the shape of the end to be ground closed end. The closed end is a kind of end shape of the compression coil spring, and is a shape in which the end is in contact with the adjacent coil in the coil axial direction.

  However, in the present embodiment, the spring receiving surfaces that support both end portions of the compression coil spring are the inclined surfaces 125 and 145, respectively. For this reason, when the closed-end compression coil spring 27G whose end is ground is adopted, the corner (edge) 27e of the ground flat seating surface 27b comes in contact with the inclined surfaces 125, 145.

  When the corner 27e of the seating surface 27b is in contact with the inclined surfaces 125 and 145, the compression coil spring 27G may be in an unstable state. In this case, in the process of contraction of the compression coil spring 27G, there is a possibility that the compression coil spring 27G may be bent in a direction perpendicular to the support axis O, and inclined surfaces 125 and 145 with which the corner 27e of the seating surface 27b contacts. The end of the compression coil spring 27G may be scraped.

  So, in this embodiment, as shown to FIG. 2A, the compression coiled spring 27 made into the non-grinding closed end which is not given the grinding process which makes a bearing surface flat is employ | adopted. Since the cross-sectional shape of the end of the compression coil spring 27 is circular and the outer peripheral curved surface of the wire contacts the inclined surfaces 125 and 145, the compression coil spring 27 can be disposed in a stable state. As a result, it is possible to prevent the compression coil spring 27 from being bent in the direction orthogonal to the support axis O and to prevent the inclined surfaces 125 and 145 and the end of the compression coil spring 27 from being scraped off.

  The compression coil spring 27 is preferably in contact with the inclined surfaces 125 and 145 in a range R of 180 degrees or more. In the present embodiment, the arc portion 27 a is provided from the tip to a range R of 180 degrees or more around the central axis of the coil. The central axis of the wire forming the arc portion 27a is orthogonal to the central axis of the coil. This makes it possible to improve the seating of the compression coil spring 27 (the stability of the arrangement).

  The arc portion 27 a corresponds to a part or all of the end winding portion of the compression coil spring 27. For this reason, it is preferable that the number of end turns of the end of the compression coil spring 27 in contact with the inclined surfaces 125 and 145 be 0.5 or more. As a result, the coiled portion 27 in contact with the inclined surfaces 125 and 145 is secured 180 degrees or more, so that the compression coil spring 27 is stably held by the inclined surfaces 125 and 145 as compared with the case where the number of coil turns is less than 0.5. Be done. The end winding portion is a portion that apparently does not act as a spring at the end of the compression coil spring 27.

  FIG. 3 is a view showing a flange 922c and a cover member 914 for supporting the compression coil spring 27 of the displacement detection device 900 according to the comparative example. As shown in FIG. 3, the flange 922 c of the rod member 922 according to the comparative example includes a disc-like base 927 and a disc-like projection 928 provided to project from the base 927 to the magnet 24. Have. The end face of the magnet 24 abuts on the projection 928. The end of the compression coil spring 27 is in contact with the outer peripheral edge of the base 927, and the projection 928 is inserted into the end of the compression coil spring 27. In the flange 922 c of the rod member 922, the spring receiving surface 924 supporting the compression coil spring 27 is a flat surface orthogonal to the support axis O.

  The lid member 914 includes a disk-like flange 914 d fixed to the case body 920 by a fastening member (not shown) such as a bolt, and a disk-like base 914 b projecting from the flange 914 d toward the inside of the case body 920. And a disk-like protrusion 914c protruding from the base 914b toward the magnet 24. The flange 914d has an area larger than the opening area of the opening 912g, and is arranged to cover the opening 912g. The base 914 b is inserted inside the case body 120 via the O-ring 48. The end of the compression coil spring 27 abuts on the outer peripheral edge of the base 914 b, and the projection 914 c is inserted inside the compression coil spring 27. In the lid member 914, a spring receiving surface 945 supporting the compression coil spring 27 is a flat surface orthogonal to the support axis O.

  Here, if the inner diameter of the compression coil spring 27 is smaller than the outer diameter of the projection 928, 914c due to a manufacturing error, the projection 928, 914c can not be inserted into the compression coil spring 27. In this case, the compression coil spring 27 can not abut on the spring receiving surfaces 924 and 945 of the base portions 927 and 914 b. On the other hand, if the inner diameter of the compression coil spring 27 is larger than the outer diameter of the projecting portion 928, 914c due to a manufacturing error, as shown in the figure, the gap between the inner periphery of the compression coil spring 27 and the outer periphery Will occur. Thus, the central axis of the compression coil spring 27 may be inclined or deviated with respect to the support axis O with respect to the rod member 922.

  When the central axis of the compression coil spring 27 is inclined with respect to the support axis O, the biasing force (axial force) in the displacement direction generated according to the displacement of the rod member 922 inclines the central axis of the compression coil spring 27 An error occurs with respect to the biasing force in the non-operating state. That is, the axial force acting on the rod member 922 is different from the design characteristic. Therefore, the displacement amount detected when the central axis of the compression coil spring 27 is inclined has an error with respect to the actual displacement amount, and as a result, the detection accuracy of the displacement detection device 900 may be lowered.

  On the other hand, in the present embodiment, as shown in FIG. 1, the end of the compression coil spring 27 on both the flange 22c and the lid member 14 so that the central axis of the compression coil spring 27 coincides with the support axis O. An inclined surface 125, 145 is provided to support the section. The inclined surfaces 125 and 145 are inclined with respect to a plane (spring receiving surfaces 924 and 945 shown in FIG. 3) orthogonal to the support axis O. Thereby, even if there is a manufacturing error, the inclination of the compression coil spring 27 can be suppressed, so that the error of the biasing force (axial force) in the displacement direction by the compression coil spring 27 can be reduced. As a result, detection of the displacement detection device 100 Accuracy can be improved.

  Since the compression coil spring 27 slightly expands in diameter as it contracts, the outer circumference of the compression coil spring 27 and the inner circumference of the case body 120 are avoided in order to avoid contact between the compression coil spring 27 and the inner circumference of the case body 120. There is a gap between the However, as shown in FIG. 3, in the displacement detection device 900 according to the comparative example, the central axis of the compression coil spring 27 may be displaced with respect to the support axis O due to a manufacturing error, an assembly error, or the like. In a state where the compression coil spring 27 is eccentric, when the rod member 22 reciprocates, the outer periphery of the compression coil spring 27 and the inner periphery of the case main body 920 come in contact with each other, which may cause the case main body 920 to wear.

  When the case body 920 is worn, contamination may occur in which scraps intrude into the sliding portion of the shaft 22a, and the bush 18 and the shaft 22a may be damaged by the scrap. When the gap between the case main body 920 and the compression coil spring 27 is increased in order to prevent wear in the comparative example, there is a possibility that the radial dimension of the case main body 920 may be increased.

  Further, in a state in which the compression coil spring 27 is eccentric, when the rod member 22 reciprocates, the inner periphery of the compression coil spring 27 and the outer periphery of the magnet 24 come in contact with each other, which may cause the magnet 24 to wear. When the magnet 24 wears, the magnetic characteristics may change, and the detection accuracy of the displacement detection device 100 may decrease. When the magnet 24 is made smaller and the gap between the magnet 24 and the compression coil spring 27 is made larger in the comparative example in order to prevent wear, the distance from the magnetic detection unit 32 to the magnet 24 is increased. The detection accuracy of 900 may be reduced.

  On the other hand, in the present embodiment, as shown in FIG. 1, the central axis of the compression coil spring 27 is positioned so as to coincide with the support axis O by the inclined surfaces 125 and 145 supporting the compression coil spring 27. Ru. For this reason, when the rod member 22 reciprocates, it can prevent that the outer periphery of the compression coiled spring 27 and the inner periphery of the case main body 120 contact. As a result, it is possible to prevent the case body 120 from being worn out, and to prevent the occurrence of contamination due to the wear of the case body 120.

  Moreover, when the rod member 22 reciprocates, it can prevent that the inner periphery of the compression coiled spring 27 and the outer periphery of the magnet 24 contact. As a result, it is possible to prevent the wear of the magnet 24 and to prevent the decrease in detection accuracy caused by the wear of the magnet 24.

  As described above, according to the present embodiment, it is possible to prevent the wear of the case body 120 and the magnet 24 while avoiding the upsizing of the displacement detection device 100, and to prevent the axial force of the compression coil spring 27 acting on the rod member 22. The detection accuracy can be improved by reducing the error of.

  The manufacturing method of the displacement detection apparatus 100 in this embodiment is demonstrated. FIG. 4 is a flowchart showing the manufacturing procedure of the displacement detection device 100. As shown in FIG. 4, the method of manufacturing the displacement detection device 100 includes a preparation step S110, a magnetic detection unit attachment step S120, a magnetic shield attachment step S130, a magnet attachment step S140, a rod member insertion step S150, and a spring. An insertion step S160, a lid member attachment step S170, and a lid member fixing step S180 are provided.

  In the preparation step S110, the rod member 22, the compression coil spring 27, the magnet 24, the substrate 34 on which the magnetic detection unit 32 is mounted, the magnetic shield 16, and the case body 120 and the lid member 14 constituting the case 12 are prepared. The bush 18 is attached to the support hole 12 d of the case main body 120 in advance.

  In the magnetic detection unit mounting step S120, the operator fixes the substrate 34 on which the magnetic detection unit 32 is mounted on the step portion of the fixing hole 12e.

  In the magnetic shield attachment step S130, the operator assembles the magnetic shield 16 into the case main body 120.

  The magnet attachment step S140 is a step of attaching the magnet 24 to the rod member 22. In the magnet attachment step S140, the operator inserts the holding shaft 22d of the rod member 22 into the insertion hole 24c of the magnet 24, and screws the nut 26 through the washer 25 to the male screw at the tip of the holding shaft 22d. By tightening the nut 26 with a predetermined tightening force, the magnet 24 is held between the nut 26 and the flange 22 c.

  In the rod member insertion step S150, the operator inserts the rod member 22 into the inside of the case body 120 from the opening 12g of the case body 120, and provides the tip of the shaft 22a of the rod member 22 on the bottom 12b of the case body 120. The support holes 12d are inserted.

  In the spring insertion step S160, the operator inserts the compression coil spring 27 into the inside of the case body 120 from the opening 12g of the case body 120, and the end of the compression coil spring 27 on the inclined surface 125 of the flange 22c of the rod member 22. Position the

  In the lid member attachment step S170, the operator inserts the lid member 14 into the opening 12g of the case main body 120, positions the end of the compression coil spring 27 on the inclined surface 145 of the lid member 14, and It is attached to the case body 120. An O-ring 48 is attached to the groove 147 of the lid member 14 in advance.

  As described above, in the present embodiment, the opening 12 g of the case body 120 is formed with a tapered surface 12 h whose inner diameter decreases from the end face of the case body 120 toward the inside of the case body 120. Therefore, when the lid member 14 is inserted into the opening 12 g, the O-ring 48 can be prevented from being caught between the opening edge and the lid member 14.

  In the cover member fixing step S180, the operator screws the fixing member 42 into the case body 120 and fixes the cover member 14 to the case body 120 by fixing the fixing member 42 to the case body 120. Here, when the fixing member 42 and the lid member 14 are integrated, one end of the compression coil spring 27 rotates with the lid member 14 in the lid member fixing step S180, and the compression coil spring 27 is twisted in the case main body 120. And the compression coil spring 27 may be damaged. On the other hand, in the present embodiment, the fixing member 42 in which a female screw is formed separately from the lid member 14 is provided. For this reason, in the cover member fixing step S180, the compression coil spring 27 is prevented from being twisted, and damage to the compression coil spring 27 can be prevented.

  In the comparative example shown in FIG. 3, no tapered surface is formed in the opening 912 g of the case main body 920. Since a slight gap is formed between the disk-shaped base 914b and the inner peripheral surface of the opening 912g, in a state where the flange 914d is attached to the case body 920 by a bolt or the like, the center of the base 914b The shaft may be slightly offset from the support axis O. When the base 914b is eccentric, the central axis of the compression coil spring 27 deviates from the support axis O even if the central axis of the base 914b coincides with the central axis of the compression coil spring 27.

  On the other hand, in the embodiment shown in FIG. 1, as described above, the tapered surface 12h is formed in the opening 12g. The worker attaches the lid member 14 to the case body 120 and pushes the lid member 14 by the fixing member 42. As a result, the contact surface 142 of the lid member 14 contacts the tapered surface 12 h of the opening 12 g, so positioning of the lid member 14 with respect to the case main body 120 can be performed easily and accurately.

  Thus, the displacement detection device 100 is completed. In addition, the said manufacturing procedure is an example, Comprising: The order of each process is not restricted to an above-described example. For example, the magnetic detection unit attachment step S120 and the magnetic shield attachment step S130 can be performed at any timing.

  According to the first embodiment described above, the following effects can be obtained.

  (1) In the case 12 which is a support member for supporting the rod member 22, as a first spring receiving surface for supporting one end of the compression coil spring 27, the displacement direction of the rod member 22 (ie, the direction parallel to the support axis O) An inclined surface 145 is provided which is inclined with respect to a plane perpendicular to the In the rod member 22 which is a displacement member in which the magnet 24 is disposed and displaced together with the spool 51, a second spring receiving surface for supporting the other end of the compression coil spring 27 is inclined with respect to a plane orthogonal to the displacement direction. A face 125 is provided.

  By supporting the compression coil spring 27 by the inclined surfaces 125, 145, the compression coil spring 27 is positioned so that the central axis of the compression coil spring 27 coincides with the support axis O of the support hole 12d supporting the rod member 22. can do. Thereby, the inclination of the compression coil spring 27 can be suppressed, and the error of the biasing force (axial force) in the displacement direction by the compression coil spring 27 can be reduced. As a result, the detection accuracy of the displacement detection device 100 can be improved.

  (2) Moreover, when the rod member 22 reciprocates, it can prevent that the outer periphery of the compression coiled spring 27 and the inner periphery of case 12 contact. As a result, abrasion of the case 12 can be prevented, and the occurrence of contamination due to the abrasion of the case 12 can be prevented.

  (3) Each of the inclined surface 125 and the inclined surface 145 is an outer peripheral surface of the tapered portion 128 and the distal end side tapered portion 14 c which tapers toward the inside of the compression coil spring 27 and contacts the inner periphery of the compression coil spring 27. . Since the tapered portion 128 and the distal end side tapered portion 14c are disposed inside the compression coiled spring 27, the radial dimension of the case 12 in comparison with the case where the tapered portion is disposed outside the compressed coiled spring 27 (see FIG. 6). Can be made smaller. That is, the displacement detection device 100 can be miniaturized.

  (4) Since the magnet 24 is disposed inside the compression coil spring 27, the axial dimension of the case 12 can be made smaller than when the magnet 24 is disposed outside the compression coil spring (see FIG. 7) . That is, the displacement detection device 100 can be miniaturized.

  (5) When the rod member 22 reciprocates, it can prevent that the inner periphery of the compression coiled spring 27 and the outer periphery of the magnet 24 contact. As a result, it is possible to prevent the magnet 24 from being abraded, and to prevent a decrease in detection accuracy caused by the abrading of the magnet 24.

  (6) When the shape of the end of the compression coil spring 27 is an open end, the compression coil spring 27 may be inclined with respect to the support axis O. On the other hand, in the present embodiment, since the shape of the end of the compression coil spring 27 in contact with the inclined surfaces 125 and 145 is a closed end, the compression coil spring 27 is inclined with respect to the support axis O Can be prevented, and the stability of the arrangement of the compression coil spring 27 can be improved.

  (7) Furthermore, in the present embodiment, the shape of the end of the compression coil spring 27 in contact with the inclined surfaces 125 and 145 is a non-grinding closed end. Thereby, the stability of the arrangement of the compression coil spring 27 can be improved as compared with the case of grinding the closed end.

  (8) The end of the compression coil spring 27 in contact with the inclined surfaces 125 and 145 is in contact with the inclined surfaces 125 and 145 in a range R of 180 degrees or more. Thereby, the stability of the arrangement of the compression coil spring 27 can be improved.

  (9) The case 12 has a bottomed cylindrical case main body 120 in which the compression coil 27 spring is accommodated, and a lid member 14 that closes the opening 12 g of the case main body 120. The opening 12 g of the case body 120 has a tapered surface 12 h whose diameter decreases toward the inside of the case body 120. An inclined surface 145, which is a first spring receiving surface, is provided on the distal end side of the lid member 14, and a contact surface 142 that is in surface contact with the tapered surface 12h of the opening 12g is provided on the proximal end side of the lid member 14. . As a result, the lid member 14 can be accurately positioned in the opening 12 g of the case main body 120, so that the positioning accuracy of the compression coil spring 27 supported by the lid member 14 can be improved.

  (10) The displacement detection device 100 includes an annular O-ring 48 that seals between the lid member 14 and the case body 120. Thereby, the hydraulic oil inside case 12 can be sealed. The lid member 14 is provided with a groove 147 in which the O-ring 48 is mounted, between the inclined surface 145 on the distal end side and the contact surface 142 on the proximal end side. Since the tapered surface 12 h is provided at the opening 12 g of the case body 120, the O-ring 48 is caught between the case body 120 and the lid member 14 when the lid member 14 is attached to the opening 12 g. Can be prevented. That is, according to the present embodiment, the positioning accuracy of the lid member 14 with respect to the case main body 120 can be improved by utilizing the tapered surface 12 h that prevents the O-ring 48 from being bitten.

  (11) The displacement detection device 100 includes the fixing member 42 that fixes the lid member 14 to the case main body 120. The fixing member 42 includes a pressing portion 42 a that presses the lid member 14 toward the inside of the case main body 120, and a fixing portion 42 b that is fixed to the case main body 120. According to such a configuration, it is only necessary to insert the lid member 14 in one direction into the opening 12 g of the case main body 120. Since it is not necessary to rotate the lid member 14, in the process of inserting the lid member 14 into the opening 12g, it is possible to prevent a defect such as the compression coil spring 27 being twisted and damaged by the rotation of the lid member 14.

  (12) The fixing member 42 is a magnetic shield capable of shielding magnetism, and the pressing portion 42 a covers a proximal end surface 141 which is an end surface on the proximal end side of the lid member 14. Thereby, the influence of the magnetism outside the displacement detection device 100 on the magnetism detection unit 32 can be suppressed. Since the fixing member 42 for fixing the lid member 14 has a function as a magnetic shield, it is not necessary to provide a member exclusively for the magnetic shield which covers the base end side of the lid member 14 separately from the fixing member 42. For this reason, the component parts of the displacement detection apparatus 100 can be reduced.

  (13) In the displacement detection device 100, the accommodation portion 12c in which the flange 22c of the rod member 22 is accommodated is filled with the hydraulic oil. Since the hydraulic oil in the housing portion 12c flows through the gap between the flange 22c and the cylindrical portion 12a when the rod member 22 is displaced in the direction of the support axis O, the rod member 22 moves in the direction in which the rod member 22 moves. It receives resistance from the hydraulic fluid that acts in the opposite direction. In this embodiment, since the compression coil spring 27 is positioned by the inclined surfaces 125 and 145, even if a force from the hydraulic oil acts on the compression coil spring 27, it is possible to prevent the occurrence of positional deviation in the radial direction. .

  (14) The operator sequentially inserts the rod member 22 and the compression coil spring 27 from the opening 12g of the bottomed cylindrical case main body 120, and closes the opening 12g with the lid member 14. In this embodiment, various parts need to be assembled to the case body 120 from one side (the opening 12g side) of the case body 120, but since the compression coil spring 27 is positioned by the inclined surfaces 125 and 145, the compression coil spring The 27 alignment operations can be performed easily and accurately.

Second Embodiment
A displacement detection device 200 according to a second embodiment of the present invention will be described with reference to FIG. In the following description, differences from the first embodiment are mainly described, and in the figure, the same reference numerals are given to the same or corresponding components as the components described in the first embodiment, and the description is omitted. .

  FIG. 5 is a cross-sectional view of a displacement detection device 200 according to a second embodiment of the present invention. In the second embodiment, the fixing member 42 and the O-ring 48 (see FIG. 1) in the first embodiment are not provided. Further, in the second embodiment, the shape of the lid member 214 constituting the case 212 is different from that of the first embodiment.

  As shown in FIG. 5, the lid member 214 has a disk-like flange 214d provided on the base end side, a base end side taper portion 214a projecting from the flange 214d toward the inside of the case main body 120, and the base end side. And a distal end side taper portion 214c protruding from the taper portion 214a toward the inside of the case main body 120.

  The proximal end tapered portion 214 a and the distal end tapered portion 214 c are each formed in a tapered shape whose diameter decreases toward the distal end side of the lid member 214. The outer peripheral surface of the proximal end tapered portion 214 a is a contact surface 142 that is in surface contact with the tapered surface 12 h of the opening 12 g of the case body 120. The outer peripheral surface of the distal end side taper portion 214 c is an inclined surface 145 with which the end of the compression coil spring 27 abuts.

  The flange 214 d is fixed to the case body 120 by a bolt 242. In the present embodiment, the bolt 242 corresponds to a fixing member for fixing the lid member 214 to the case main body 120. The head of the bolt 242 corresponds to a pressing portion that presses the lid member 214 toward the inside of the case body 120, and the shaft portion of the bolt corresponds to a fixing portion fixed to the case body 120.

  According to such a second embodiment, the same operation and effect as (1) to (9), (11) and (14) described in the first embodiment can be obtained.

  The following modifications are also within the scope of the present invention, and the configuration shown in the modification and the configuration described in the above embodiment may be combined, the configurations described in the different embodiments above may be combined, or the following differences It is also possible to combine the configurations described in the modification.

(Modification 1)
Although the outer surface of the tip side taper parts 14c and 214c in the lid members 14 and 214 is described as an inclined surface 145 in contact with the inner periphery of the compression coil spring 27 in the embodiment described above, the present invention It is not limited. For example, as in the displacement detection device 300 shown in FIG. 6, a recess 340 which is recessed toward the base end is provided on the outer peripheral edge on the distal end side of the lid member 314 constituting the case 312. An inclined surface 345 may be provided to be in contact with the outer periphery of the end portion (radially outside the center diameter of the coil spring). According to such a modification, the same operation and effect as (1), (2) and (4) to (14) described in the first embodiment can be obtained.

(Modification 2)
Although the embodiment described above describes the example in which the magnet 24 is disposed inside the compression coil spring 27, the present invention is not limited to this. As shown in FIG. 7, the magnet 24 and the compression coil spring 427 may be arranged in line in the axial direction. In the displacement detection device 400 according to the present modification, one end of the compression coil spring 427 is supported by the inclined surface 445 provided on the lid member 414 constituting the case 412, and the other end of the compression coil spring 427 is a configuration of the displacement member. It is supported by an inclined surface 425 provided on a nut 426 which is a part. The inclined surface 445 is in contact with the inner periphery of the end of the compression coil spring 427, similarly to the inclined surface 145 described in the first embodiment. The inclined surface 425 is in contact with the inner periphery of the end of the compression coil spring 427, similarly to the inclined surface 125 described in the first embodiment. According to such a modification, the same operation and effect as (1) to (3) and (6) to (14) described in the first embodiment can be obtained.

(Modification 3)
In the embodiment described above, an example is described in which both of the spring receiving surfaces that support both end portions of the compression coil spring 27 are inclined surfaces, but the present invention is not limited to this. One of the spring receiving surfaces for supporting both end portions of the compression coil spring 27 may be an inclined surface, and the other may be a plane orthogonal to the displacement direction. Even in such a case, the central axis of the compression coil spring 27 with respect to the support axis O compared to the case where both of the spring receiving surfaces supporting the both ends of the compression coil spring 27 are planes orthogonal to the displacement direction. And the inclination of the compression coil spring 27 can be suppressed.

(Modification 4)
In the embodiment described above, the example in which the nut 26 is screwed to the holding shaft 22d and the magnet 24 is held between the nut 26 and the flange 22c of the rod member 22 has been described, but the present invention is not limited thereto. Instead of the nut 26, the magnet 24 may be fixed to the holding shaft 22d by a caulking portion formed by caulking the tip of the holding shaft 22d. In this case, the caul plate disposed between the caulking portion and the magnet 24 is preferably formed of a magnetic material.

(Modification 5)
In the first embodiment, an example in which the lid member 14 is fixed to the case body 120 by the fixing member 42 is described, and in the second embodiment, an example in which the lid member 214 is fixed to the case body 120 by the bolt 242 is described. The present invention is not limited to this. When a large force does not act on the lid members 14 and 214, such as when the pressure difference between the inside and the outside of the cases 12 and 212 is small, the lid members 14 and 214 are attached to the opening 12g of the case body 120 by press fitting or adhesion. You may In this case, the fixing member 42 for fixing the lid members 14 and 214 and the bolt 242 can be omitted.

  The configuration, operation, and effects of the embodiment of the present invention configured as described above will be collectively described.

  The displacement detection devices 100, 200, 300, and 400 are disposed on the rod member 22 displaced following the spool 51, the compression coil springs 27 and 427 urging the rod member 22 toward the spool 51, and the rod member 22. The magnet 24, which is displaced together with the rod member 22, the cases 12, 212, 312, and 412 which support the rod member 22 so as to reciprocate in the displacement direction, and a magnetic detection unit which detects changes in the magnetic field accompanying the displacement of the magnet 24. 32, the case 12, 212, 312, 412 is provided with a first spring receiving surface for supporting one end of the compression coil spring 27, 427, and the rod member 22 is provided with the compression coil spring 27, 427. A second spring receiving surface for supporting the other end is provided, and at least one of the first spring receiving surface and the second spring receiving surface is relative to a plane orthogonal to the displacement direction. Is an inclined surface 145,345,445,125,425 be oblique.

  In this configuration, the inclination of the compression coil spring 27, 427 with respect to the displacement direction of the rod member 22 is suppressed by supporting the compression coil spring 27, 427 by the inclined surfaces 145, 345, 445, 125, 425. Because of this, it is possible to reduce the error in the biasing force (axial force) in the displacement direction by the compression coil spring 27, 427. As a result, the detection accuracy of the displacement detection devices 100, 200, 300, and 400 can be improved.

  In the displacement detection devices 100, 200, 300, and 400, both the first and second spring receiving surfaces are inclined surfaces 145, 345, 445, 125, and 425.

  In this configuration, since the inclined surfaces 145, 345, 445, 125, 425 are provided on both the first spring receiving surface and the second spring receiving surface, both ends of the compression coil spring 27, 427 can be properly positioned. . As a result, the positioning accuracy of the compression coil springs 27 and 427 can be improved as compared with the case where the inclined surfaces 145, 345, 445, 125 and 425 are provided on one of the first spring receiving surface and the second spring receiving surface. The inclination of the springs 27, 427 can be suppressed more effectively.

  In the displacement detection device 100, 200, 400, the inclined surfaces 145, 445, 125, 425 are the outer peripheral surfaces of the tapered portions (14c, 214c, 128) which are tapered toward the inside of the compression coil springs 27, 427, It contacts the inner circumference of the compression coil spring 27, 427.

  In this configuration, since the tapered portion (14c, 214c, 128) is disposed inside the compression coil spring 27, 427, the displacement detection device is compared to the case where the tapered portion is disposed outside the compression coil spring 27, 427. 100, 200, 400 can be miniaturized.

  In the displacement detection devices 100, 200, and 300, the magnet 24 is disposed inside the compression coil spring 27.

  In this configuration, since the magnet 24 is disposed inside the compression coil spring 27, the displacement detection devices 100, 200, and 300 can be miniaturized as compared with the case where the magnet 24 is disposed outside the compression coil spring 27. Since the compression coil spring 27 is properly positioned by the inclined surfaces 145, 345 and 125, the inner circumference of the compression coil spring 27 and the outer circumference of the magnet 24 can be prevented from contacting when the rod member 22 reciprocates. As a result, wear of the magnet 24 can be prevented.

  In the displacement detection devices 100, 200, 300, and 400, the shapes of the end portions of the compression coil springs 27, 427 in contact with the inclined surfaces 145, 345, 445, 125, and 425 are non-grinding closed ends.

  In this configuration, since the shape of the end of the compression coil spring 27, 427 in contact with the inclined surfaces 145, 345, 445, 125, 425 is a non-grinding closed end, the shape of the end of the compression coil spring 27, 427 is The stability of the arrangement of the compression coil springs 27, 427 can be improved as compared to the case of the open end and the case of the closed end after grinding.

  In the displacement detection devices 100, 200, 300, and 400, the end portions of the compression coil springs 27, 427 are in contact with the inclined surfaces 145, 345, 445, 125, and 425 in a range R of 180 degrees or more.

  In this configuration, since the end of the compression coil spring 27, 427 is in contact with the inclined surfaces 145, 345, 445, 125, 425 in a range R of 180 degrees or more, the inclined surfaces 145, 345, 445, 125, 425 The stability of the arrangement of the compression coil springs 27, 427 can be improved as compared with the case where the range of contact is less than 180 degrees.

  In the displacement detection devices 100, 200, 300, and 400, the cases 12, 212, 312, and 412 have a bottomed cylindrical case main body 120 in which the compression coil springs 27, 427 are accommodated, and an opening 12g of the case main body 120. The opening 12g has a tapered surface 12h whose diameter decreases toward the inside of the case main body 120, and the opening 12g has a cover 14 14, 214, 314, 414. A first spring receiving surface is provided on the distal end side, and a contact surface 142 which is in surface contact with the tapered surface 12 h of the opening 12 g is provided on the proximal end side of the lid members 14, 214, 314, 414.

  In this configuration, the case main body 120 is brought into surface contact with the tapered contact surface 142 provided on the lid member 14, 214, 314, 414 by the tapered surface 12h provided on the opening 12g of the case main body 120. The positioning accuracy of the lid members 14, 214, 314, 414 with respect to the above can be improved. Thereby, the positioning accuracy of the compression coil spring 27, 427 supported by the first spring receiving surface of the cover member 14, 214, 314, 414 can be improved.

  The displacement detection device 100, 300, 400 further includes an annular O-ring 48 that seals between the lid members 14, 314, 414 and the case main body 120, and the first spring receiving surface is the inclined surface 145. The member 14, 314, 414 is provided with a groove 147 between the inclined surface 145 and the contact surface 142 in which the O-ring 48 is mounted.

  In this configuration, in the displacement detection device 100, 300, 400 capable of sealing the fluid inside the case by the O-ring 48, the opening 12g of the case body 120 is provided with the tapered surface 12h. , 314, 414 can be prevented from being caught between the case body 120 and the lid members 14, 314, 414 when the O-ring 48 is attached to the opening 12g. That is, the positioning accuracy of the lid members 14, 314, 414 with respect to the case main body 120 can be improved by utilizing the tapered surface 12h which prevents the O-ring 48 from biting.

  The displacement detection apparatus 100, 200, 300, 400 further includes a fixing member 42 for fixing the lid member 14, 214, 314, 414 to the case main body 120, and a bolt 242. The fixing member 42 and the bolt 242 are the lid member 14, A pressing portion 42 a for pressing the members 214, 314, and 414 toward the inside of the case main body 120 and a fixing portion 42 b fixed to the case main body 120 are provided.

  In this configuration, when the cover members 14, 214, 314, 414 are fixed to the case body 120, the cover members 14, 214, 314, 414 may be inserted in one direction only into the opening 12g of the case body 120. Good. Since it is not necessary to rotate the lid members 14, 214, 314, 414, the compression coil is rotated by the rotation of the lid members 14, 214, 314, 414 in the process of inserting the lid members 14, 214, 314, 414 into the opening 12g. The springs 27 and 427 can be prevented from being twisted and damaged.

  In the displacement detection devices 100, 300, and 400, the fixing member 42 is a magnetic shield capable of shielding magnetism, and the pressing portion 42a covers the proximal end surface 141 of the lid member 14, 314, and 414.

  In this configuration, it is possible to suppress the influence of the magnetism outside the displacement detection devices 100, 300, 400 on the magnetism detection unit 32. Further, since the fixing member 42 has a function as a magnetic shield, it is not necessary to provide a member dedicated to the magnetic shield which covers the base end side of the lid members 14, 314 and 414 separately from the fixing member 42. Therefore, the component parts of the displacement detection devices 100, 300, and 400 can be reduced.

  The manufacturing method of the displacement detection devices 100, 200, 300, 400 includes a rod member 22 displaced following the spool 51, compression coil springs 27 and 427 urging the rod member 22 toward the spool 51, and a rod member 22. A magnet 24, which is displaced with the rod member 22, and a compression coil spring 27, 427 are accommodated, and cases 12, 212, 312, 412 which reciprocately support the rod member 22 in the displacement direction, a magnet 24 And a first spring receiving surface for supporting one end of the compression coil spring 27, 427 in the case 12, 212, 312, 412. The rod member 22 is provided with a second spring receiving surface for supporting the other end of the compression coil spring 27, 427, and has a first spring receiving surface and a second spring receiving surface. At least one of them is an inclined surface 145, 345, 445, 125, 425 inclined with respect to a plane orthogonal to the displacement direction, and the case 12, 212, 312, 412 accommodates the compression coil spring 27, 427. A method of manufacturing a displacement detection device 100, 200, 300, 400 having a bottomed cylindrical case body 120 and lid members 14, 214, 314, 414 for closing the opening 12g of the case body 120, wherein the rod is The magnet mounting step S140 for attaching the magnet 24 to the member 22 and the rod member 22 inserted into the case body 120 from the opening 12g, one end of the rod member 22 in the support hole 12d provided in the bottom 12b of the case body 120 Insert the compression coil spring 27, 427 into the case main body 120 from the opening 12g through the rod member insertion step S150 to be inserted. , The spring insertion step S160 for positioning the other end of the compression coil spring 27, 427 on the second spring receiving surface of the rod member 22, and the lid members 14, 214, 314, 414 into the opening 12g. A cover member mounting step S170 for positioning one end of the compression coil spring 27, 427 on the first spring receiving surface of the housings 214, 314, 414 and attaching the cover members 14, 214, 314, 414 to the case main body 120; And a lid member fixing step S180 for fixing the lid members 14, 214, 314, and 414 to the case body 120 by fixing 42 to the case body 120.

  In this configuration, the lid members 14, 214, 314, and 414 need only be inserted in one direction into the opening 12g of the case body 120. Since it is not necessary to rotate the lid members 14, 214, 314, 414, the compression coil is rotated by the rotation of the lid members 14, 214, 314, 414 in the process of inserting the lid members 14, 214, 314, 414 into the opening 12g. The springs 27 and 427 can be prevented from being twisted and damaged. In the assembled displacement detection device 100, 200, 300, 400, the central axis of the compression coil spring 27, 427 is the rod member 22 by the inclined surfaces 145, 345, 445, 125, 425 supporting the compression coil spring 27, 427. Are positioned to coincide with the support axis O of the support hole 12d that supports the Thereby, it is possible to reduce the error of the biasing force (axial force) in the displacement direction (direction parallel to the support axis O) by the compression coil spring 27, 427. As a result, the detection accuracy of the displacement detection devices 100, 200, 300, and 400 can be improved.

  As mentioned above, although the embodiment of the present invention was described, the above-mentioned embodiment showed only a part of application example of the present invention, and in the meaning of limiting the technical scope of the present invention to the concrete composition of the above-mentioned embodiment. Absent.

  12: Case (supporting member), 12b: bottom, 12d: supporting hole (through hole), 12g: opening, 12h: tapered surface, 14: lid member, 14c · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 27 · 27G · · · compression coil spring, 32 · · · magnetic detection unit, 42 · · · Fixing member 42a: pressing portion 42b: fixing portion 48: O ring (seal member) 51: spool (displacement detection target member) 100: displacement detection device 120 · · Case main body 125 · · · inclined surface 128 · · · tapered portion 142 contact surface 145 inclined surface 147 groove 200 displacement detection device 212・ Case (supporting member), 214 ··· Lid member, 214 c ····· Tip side tee Cap part (taper part), 242 ... bolt (fixed member), 300 ... displacement detection device, 312 ... case (support member), 314 ... lid member, 345 ... inclined surface, 400 ... displacement detection device, 412 ... case (support member), 414 ... lid member, 425 ... inclined surface, 427 ... compression coil spring, 445 ... inclined surface

Claims (9)

A displacement member which is displaced following a displacement detection target member;
A compression coil spring for biasing the displacement member toward the displacement detection target member;
A magnet disposed on the displacement member and displaced together with the displacement member;
A support member that supports the displacement member so as to reciprocate in the displacement direction;
And a magnetic detection unit that detects a change in a magnetic field caused by the displacement of the magnet.
The support member is provided with a first spring receiving surface for supporting one end of the compression coil spring.
The displacement member is provided with a second spring receiving surface for supporting the other end of the compression coil spring.
At least one of said 1st spring bearing surface and said 2nd spring bearing surface is an inclined surface which inclines with respect to the plane orthogonal to the said displacement direction, The displacement detection apparatus characterized by the above-mentioned. In the displacement detection device according to claim 1,
A displacement detection device characterized in that both the first spring bearing surface and the second spring bearing surface are the inclined surfaces. In the displacement detection device according to claim 1 or 2,
The displacement detecting device according to claim 1, wherein the inclined surface is an outer peripheral surface of a tapered portion which is tapered toward the inside of the compression coil spring, and is in contact with an inner periphery of the compression coil spring. The displacement detection device according to any one of claims 1 to 3.
The displacement detecting device, wherein the magnet is disposed inside the compression coil spring. The displacement detection device according to any one of claims 1 to 4.
A shape of the end of the compression coil spring in contact with the inclined surface is a non-grinding closed end. In the displacement detection device according to claim 5,
An end portion of the compression coil spring is in contact with the inclined surface in a range of 180 degrees or more. The displacement detection device according to any one of claims 1 to 6.
The support member is
A bottomed cylindrical case body in which the compression coil spring is accommodated;
And a lid member closing the opening of the case body,
The opening has a tapered surface whose diameter decreases toward the inside of the case body,
The first spring receiving surface is provided on the tip side of the lid member,
The proximal end side of the lid member is provided with a contact surface which is in surface contact with the tapered surface of the opening. In the displacement detection device according to claim 7,
It further comprises a fixing member for fixing the lid member to the case body,
The fixing member is a magnetic shield capable of shielding magnetism, and has a pressing portion for pressing the lid member toward the inside of the case main body, and a fixing portion fixed to the case main body,
The displacement detecting device, wherein the pressing portion covers an end face on a proximal end side of the lid member. A displacement member which is displaced following a displacement detection target member;
A compression coil spring for biasing the displacement member toward the displacement detection target member;
A magnet disposed on the displacement member and displaced together with the displacement member;
A case in which the compression coil spring is accommodated and which reciprocably supports the displacement member in the displacement direction;
And a magnetic detection unit that detects a change in a magnetic field caused by the displacement of the magnet.
The case is provided with a first spring receiving surface for supporting one end of the compression coil spring.
The displacement member is provided with a second spring receiving surface for supporting the other end of the compression coil spring.
At least one of the first spring receiving surface and the second spring receiving surface is an inclined surface which is inclined with respect to a plane orthogonal to the displacement direction,
The case is
A bottomed cylindrical case body in which the compression coil spring is accommodated;
And a lid member for closing the opening of the case body.
A magnet attaching step of attaching the magnet to the displacement member;
A displacement member insertion step of inserting the displacement member into the inside of the case main body from the opening and inserting one end of the displacement member into a through hole provided in a bottom portion of the case main body;
Inserting the compression coil spring into the inside of the case body from the opening, and positioning the other end of the compression coil spring on the second spring receiving surface of the displacement member;
A lid member attaching step of inserting the lid member into the opening, positioning one end of the compression coil spring on the first spring receiving surface of the lid member, and attaching the lid member to the case main body;
And a fixing step of fixing the lid member to the case body by fixing the fixing member to the case body.

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