JP6970559B2 - Displacement detector - Google Patents

Description

The present invention relates to a displacement detection device.

Patent Document 1 describes a magnet attached to a displacement member that displaces following the object to be measured, a magnetic sensor arranged facing the magnet, and a coil spring that urges the displacement member toward the object to be measured. Displacement detection devices comprising, are disclosed. In this displacement detection device, the position of the magnet changes according to the displacement of the object to be measured, and the direction and magnitude of the magnetic flux passing through the magnetic sensor changes as the position of the magnet changes, so the output value of the magnetic sensor The amount of displacement of the object to be measured can be specified based on.

Japanese Unexamined Patent Publication No. 2016-11833

However, in the displacement detection device described in Patent Document 1, a magnet is mounted in the middle portion of the displacement member, and a coil spring is mounted between the end surface of the displacement member and the bottom surface of the case. As described above, in the displacement detection device described in Patent Document 1, since the coil spring and the magnet are arranged side by side in the displacement direction of the displacement member, there is a problem that the case becomes large in the displacement direction of the displacement member. There is.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce the size of the case.

In the first invention, a case and a displacement member in which a magnet arranged in a displacement member that is displaced following a displacement detection target member is arranged inside a compression coil spring that urges the displacement member and accommodates the compression coil spring. It is a displacement detection device characterized in that it prevents the case and the magnet from coming into contact with each other when they come into contact with each other.

In the first invention, the magnet is arranged inside the compression coil spring, and the case and the displacement member come into contact with each other to prevent the case and the magnet from coming into contact with each other. Therefore, the compression coil spring is maximized. The space inside the compression coil spring when it is bent can be effectively used as a space for arranging the magnet, and damage to the magnet is prevented.

In the second invention, the amount of deflection of the compression coil spring is regulated by the contact between the case and the displacement member, and the amount of deflection of the compression coil spring is regulated so as not to exceed the allowable amount of deflection of the compression coil spring. It is characterized by that.

In the second invention, when the displacement detection device is assembled to the device provided with the displacement detection target member and when the displacement detection device is inspected, even if a large external force acts on the displacement member, the compression coil is used. It is possible to prevent the spring from exceeding the allowable deflection amount. This can improve the life of the compression coil spring.

The third invention is characterized in that the allowable deflection amount of the compression coil spring is 10% or more and 75% or less of the free length of the compression coil spring.

In the third invention, since the allowable deflection amount of the compression coil spring is 10% or more of the free length, the range of use of the compression coil spring can be widened. Since the allowable deflection amount of the compression coil spring is 75% or less of the free length, the deformation amount of the compression coil spring can be suppressed and the life can be improved.

In the fourth invention, the magnet is formed in a cylindrical shape, and the displacement member is provided at the shaft portion whose tip abuts on the displacement detection target member and is slidably supported by the case, and at the base end of the shaft portion. , A flange on which one end of the compression coil spring is supported, and a holding shaft that extends from the flange to the opposite side of the shaft and holds the magnet inserted, and the tip of the holding shaft protruding from the magnet. It is characterized in that the amount of deflection of the compression coil spring is regulated by the portion abutting on the case.

In the fourth invention, the amount of deflection of the compression coil spring is regulated by bringing the tip of the holding shaft through which the magnet is inserted into contact with the case. Therefore, the amount of deflection of the compression coil spring is regulated by a simple configuration. can do.

A fifth aspect of the invention is characterized in that a holding member for holding a magnet between the flange and the holding member is further provided, and the holding member is made of a magnetic material.

In the fifth invention, by forming the sandwiching member that sandwiches the magnet with a magnetic material, the displacement of the displacement member can be detected more accurately than in the case where the sandwiching member is formed of a non-magnetic material.

According to the present invention, the case can be made smaller.

It is sectional drawing which shows the displacement detection apparatus which concerns on 1st Embodiment of this invention, and shows the state which the deflection amount of a compression coil spring is small. It is sectional drawing which shows the displacement detection apparatus which concerns on 1st Embodiment of this invention, and shows the state which the deflection amount of a compression coil spring is large. It is sectional drawing which shows the displacement detection apparatus which concerns on 1st Embodiment of this invention, and shows the state which the deflection amount of a compression coil spring is the minimum. It is sectional drawing which shows the displacement detection apparatus which concerns on 1st Embodiment of this invention, and shows the state which the deflection amount of a compression coil spring is the maximum. It is sectional drawing of the displacement detection apparatus which concerns on 2nd Embodiment of this invention.

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

<First Embodiment>
Hereinafter, a case where the displacement detection device 100 is used as a stroke sensor for detecting the displacement amount (stroke amount) of the spool (valve body) 51 of the hydraulic valve device 50 will be described.

As shown in FIG. 1, the hydraulic valve device 50 includes a cylindrical sleeve 52 and a spool 51 arranged in the sleeve 52 and reciprocating in the axial direction. In the hydraulic valve device 50, the spool 51 is displaced in the axial direction by supplying and discharging hydraulic oil to the oil chamber 53 facing the oil chamber 53 facing one end surface 51a of the spool 51 through the supply / discharge holes 52a provided in the sleeve 52. The displacement of the spool 51 controls the opening and closing of a port (not shown) formed on the sleeve 52. The displacement detection device 100 is attached to the end of the sleeve 52 so as to face the one end surface 51a of the spool 51.

The displacement detection device 100 includes a rod member 22 as a displacement member that is displaced following the spool 51 that is a displacement detection target member, a compression coil spring 27 that urges the rod member 22 toward the spool 51, and a rod member 22. A magnet 24 that is arranged on one end side of the magnet 24 and displaces with the rod member 22, a case 12 that houses the compression coil spring 27 and reciprocally supports the rod member 22 in the displacement direction, and a direction orthogonal to the displacement direction of the magnet 24. A magnetic detection unit 32 arranged in the case 12 so as to face the magnet 24 is provided.

The case 12 has a bottomed cylindrical case body 120 in which the compression coil spring 27 is housed, 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 made of a non-magnetic material such as brass. The case body 120 is formed inside the cylindrical portion 12a, the bottom portion 12b provided on one end side of the cylindrical portion 12a, the opening portion 12g provided on the other end side of the cylindrical portion 12a, and the inside of the cylindrical portion 12a. It has an accommodating portion 12c and. A part of the rod member 22 in which the magnet 24 is arranged together with the magnet 24 is accommodated in the accommodating portion 12c.

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

A support hole 12d through which the shaft portion 22a of the rod member 22 is inserted is formed through the bottom portion 12b of the case body 120. Bush 18s, which are bearings that slidably support the shaft portion 22a of the rod member 22, are provided in the support holes 12d at two locations separated in the axial direction. By providing the bushes 18 at two positions, it is possible to prevent the axis of the rod member 22 cantilevered and supported by the case body 120 from tilting with respect to the support axis O which is the axis 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.

A plurality of communication holes 12f for communicating the accommodating portion 12c and the outside are formed around the support hole 12d in the bottom portion 12b of the case main body 120. 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 accommodating portion 12c through the communication hole 12f. That is, the accommodating portion 12c is filled with hydraulic oil.

The rod member 22 has a columnar shaft portion 22a slidably supported by a case body 120 via a bush 18, a hemispherical contact end portion 22b formed at the tip of the shaft portion 22a, and a shaft portion 22a. It has a substantially disk-shaped flange 22c formed at the base end of the shaft portion 22a and extending outward in the radial direction.

The rod member 22 is made of a non-magnetic material like the case 12. Since the spool 51 comes into contact with the contact end portion 22b of the rod member 22, the rod member 22 is formed of austenitic stainless steel or the like having a hardness higher than that of brass.

The flange 22c is provided with a columnar holding shaft 22d extending on the side opposite to the shaft portion 22a coaxially with the shaft portion 22a. At the tip of the holding shaft 22d, a male screw into which the female screw of the nut 26, which will be described later, is screwed is formed. By design, the rod member 22 is supported by the case body 120 so that the central axis of the rod member 22 and the support axis O of the support hole 12d are arranged coaxially. That is, the central axis of the rod member 22 coincides with the support axis O.

A step portion 22f facing the step portion 14d of the lid member 14, which will be described later, is provided on the outer peripheral edge portion of the flange 22c, and the end portion (left end in the drawing) of the compression coil spring 27 abuts on the step portion 22f.

The magnet 24 is a permanent magnet formed in a cylindrical shape containing rare earth elements such as Nd and Sm, and is formed 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 a nut 26 is attached to the tip of the holding shaft 22d protruding from the insertion hole 24c via a washer 25. As a result, the magnet 24 is fixed to the holding shaft 22d while being sandwiched by the flange 22c, the nut 26, and the washer 25. The nut 26 and the washer 25 are made of a magnetic material. The nut 26 and the washer 25 are parts that sandwich the magnet 24 with the flange 22c, and are constituent parts of the displacement member that follows the spool 51 and is displaced in the displacement direction.

Since the magnet 24 is fixed to the rod member 22, as shown in FIGS. 1 and 2, the magnet 24 follows the spool 51 together with the rod member 22 and is displaced along the support axis O within the displacement range R1. The change in the magnetic field due to the displacement of the magnet 24 is detected by the magnetic detection unit 32.

The magnetic detection unit 32 includes a magnetic sensor (not shown) such as a Hall element or a magnetoresistive element that outputs an output value according to a change in the magnetic field due to the displacement of the magnet 24, and an amplification circuit that processes the output value of the magnetic sensor. Has a processing circuit (not shown). 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 magnitude of the magnetic flux passing through the magnetic detection unit 32 are changed. The output value of the magnetic detection unit 32 changes according to a change in the direction and magnitude 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.

As shown in FIG. 1, the magnetic detection unit 32 is mounted on the substrate 34, and is assembled to the case body 120 by fixing the substrate 34 to the stepped portion of the fixing hole 12e formed in the cylindrical portion 12a. ..

With the magnetic detection unit 32 arranged in the fixing hole 12e, a 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 alloy capable of shielding magnetism, and suppresses the influence of the external magnetism of the displacement detection device 100 on the magnetic detection unit 32.

A notch (not shown) is formed in the magnetic shield 16, and a lead wire (not shown) connecting the controller (not shown) that controls the operation of the spool 51 and the magnetic detection unit 32 is arranged through the notch. NS.

The opening 12g 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 12c. The opening 12g of the case body 120 is a circular opening that communicates the accommodating portion 12c with the outside, and is continuously provided in the accommodating portion 12c.

The lid member 14 is fitted with a disk-shaped flange 14a fixed to the case body 120 by a fastening member (not shown) such as a bolt, and a disk-shaped flange protruding from the flange 14a toward the inside of the case body 120. It has a portion 14b and a disk-shaped protruding portion 14c that protrudes from the end surface of the fitting portion 14b toward the magnet 24 side. The fitting portion 14b is a portion to be fitted into the opening portion 12g of the case body 120, and an O-ring (not shown) is mounted on the outer periphery thereof.

The protruding portion 14c has a smaller diameter than the fitting portion 14b and is inserted inside the compression coil spring 27. By forming a protruding portion 14c having a smaller diameter than the fitting portion 14b on the end surface of the fitting portion 14b, a step portion 14d is formed on the lid member 14, and an end portion of the compression coil spring 27 is formed on the step portion 14d. (Right end in the figure) abuts.

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

Each of the tip surface 22e of the holding shaft 22d and the tip surface 146 of the protrusion 14c is a flat surface orthogonal to the support axis O, and abuts against each other to regulate the amount of deflection of the compression coil spring 27 as described later. .. That is, the holding shaft 22d of the rod member 22 and the protruding portion 14c of the lid member 14 have a function as a regulating portion for regulating the amount of deflection of the compression coil spring 27. Further, the holding shaft 22d protrudes from the magnet 24 toward the lid member 14, and the tip surface 146 of the protruding portion 14c of the lid member 14 and the tip surface 22e of the holding shaft 22d come into contact with each other to bring the lid member 14 and the magnet 24 together. Is prevented from coming into contact with the magnet 24, so that the magnet 24 is prevented from being damaged.

The compression coil spring 27 is an elastic member made of a non-magnetic material such as austenitic stainless steel, and is assembled in a compressed state between the flange 22c of the rod member 22 and the lid member 14. Therefore, the urging force of the compression coil spring 27 always acts in the direction of pressing the rod member 22 against the spool 51.

As shown in FIG. 3, when the displacement detection device 100 is not assembled to the hydraulic valve device 50, the rod member 22 is pressed by the urging force of the compression coil spring 27, and the flange 22c of the rod member 22 is the case body 120. It is in contact with the bottom portion 12b. As shown in the figure, when the amount of deflection of the compression coil spring 27 is the minimum, the length L of the compression coil spring 27 is a length L10 shorter than the length of the free length L0 (L10 <L0).

When the displacement detection device 100 is attached to the hydraulic valve device 50 and when the displacement detection device 100 is inspected, the contact end portion 22b of the rod member 22 may be pushed in the axial direction. When the contact end portion 22b is pushed in the axial direction, the compression coil spring 27 is compressed and the rod member 22 moves toward the lid member 14. The amount of movement of the rod member 22 and the amount of deflection of the compression coil spring 27 are regulated by the contact between the holding shaft 22d and the lid member 14.

When the contact end portion 22b of the rod member 22 is pushed in the axial direction from the state shown in FIG. 3, as shown in FIG. 4, the tip surface 22e of the holding shaft 22d and the tip surface 146 of the protrusion 14c come into contact with each other, and the rod member The axial movement of 22 is restricted. As shown in FIG. 4, when the tip end portion of the holding shaft 22d and the protruding portion 14c of the lid member 14 are in contact with each other, the length L of the compression coil spring 27 becomes the minimum length L20.

The minimum length L20 is longer than the length Lmin of the compression coil spring 27 when a load corresponding to the allowable load is applied to the compression coil spring 27 (L20> Lmin). In other words, the deflection amount F of the compression coil spring 27 is regulated so as not to exceed the allowable deflection amount Fmax of the compression coil spring 27 due to the contact between the holding shaft 22d and the protruding portion 14c. The allowable deflection amount Fmax of the compression coil spring 27 is the length obtained by subtracting the above length Lmin from the free length L0 of the compression coil spring 27 (Fmax = L0-Lmin).

When the compression coil spring 27 having a small allowable deflection amount Fmax is used, the range of use of the compression coil spring 27 is narrowed, and as a result, the displacement range R1 of the rod member 22 in the displacement detection device 100 is narrowed. Therefore, in the present embodiment, the compression coil spring 27 in which the allowable deflection amount Fmax is set to a value of 10% or more of the free length L0 of the compression coil spring is adopted. As a result, the required displacement range R1 can be secured in the displacement detection device 100 assembled to the hydraulic valve device 50.

Since the compression coil spring 27 repeatedly expands and contracts, if the amount of deflection during contraction is too large, the life of the compression coil spring 27 will be shortened. Therefore, in the present embodiment, the compression coil spring 27 in which the allowable deflection amount Fmax is set to a value of 75% or less of the free length L0 of the compression coil spring is adopted. As a result, the durability of the compression coil spring 27 can be ensured, and a sufficient life can be ensured in the displacement detecting device 100 assembled to the hydraulic valve device 50.

As shown in FIGS. 3 and 4, when the displacement detection device 100 is not attached to the hydraulic valve device 50, the magnet 24 has a support shaft within the displacement range R2 according to the pressing force acting on the rod member 22. Displace along the heart O. The displacement range R2 is the movement of the rod member 22 from the state where the rod member 22 is in contact with the bottom portion 12b of the case body 120 (see FIG. 3) to the state where the rod member 22 is in contact with the lid member 14 (see FIG. 4). It is possible.

As shown in FIGS. 1 and 2, the displacement range R1 of the rod member 22 in the state where the displacement detection device 100 is assembled to the hydraulic valve device 50 is a state in which the displacement detection device 100 is not assembled to the hydraulic valve device 50. It is set smaller than the displacement range R2 in. As shown in FIG. 1, the flange 22c does not come into contact with the bottom portion 12b of the case body 120 even when the spool 51 is moved to the left side to the maximum. That is, the length L1 of the compression coil spring 27 in the state of FIG. 1 is shorter than the length L10 of the compression coil spring 27 in the state of FIG. 3 (L1 <L10). As shown in FIG. 2, even when the spool 51 is moved to the right side to the maximum, the tip end portion of the holding shaft 22d does not come into contact with the protruding portion 14c of the lid member 14. That is, the length L2 of the compression coil spring 27 in the state of FIG. 2 is longer than the length L20 of the compression coil spring 27 in the state of FIG. 4 (L2> L20). As described above, in the present embodiment, the tip of the holding shaft 22d and the protruding portion 14c of the lid member 14 do not come into contact with each other during the operation of the hydraulic valve device 50, so that the parts are damaged due to the contact. No noise or noise.

According to the above first embodiment, the following actions and effects are exhibited.

(1) The displacement detection device 100 is configured such that the magnet 24 is arranged inside the compression coil spring 27. As a result, the space inside the compression coil spring 27 when the compression coil spring 27 is flexed to the maximum can be effectively used as a space for arranging the magnet 24, so that the axial dimension of the case 12 can be reduced. Further, the displacement detection device 100 is configured to prevent the lid member 14 of the case 12 and the magnet 24 from coming into contact with each other when the lid member 14 of the case 12 and the rod member 22 come into contact with each other. Therefore, it is possible to prevent the magnet 24 from being damaged.

(2) The deflection amount F of the compression coil spring 27 is regulated so as not to exceed the allowable deflection amount Fmax of the compression coil spring 27. When the displacement detection device 100 is assembled to the hydraulic valve device 50 and when the displacement detection device 100 is inspected, the amount of deflection that the compression coil spring 27 allows even if a large external force is applied to the rod member 22. It is possible to prevent the Fmax from being exceeded. As a result, the life of the compression coil spring 27 can be improved.

(3) A compression coil spring 27 having an allowable deflection amount Fmax set to a value of 10% or more and 75% or less of the free length L0 of the compression coil spring was adopted. Since the allowable deflection amount Fmax of the compression coil spring 27 is 10% or more of the free length L0, the range of use of the compression coil spring 27 can be widened. As a result, the displacement range R1 of the rod member 22 can be widened. Since the allowable deflection amount Fmax of the compression coil spring 27 is 75% or less of the free length L0, the deformation amount of the compression coil spring 27 can be suppressed and the life can be improved.

(4) The rod member 22 is provided at the shaft portion 22a whose tip is in contact with the spool 51 and is slidably supported by the case 12 and at the base end of the shaft portion 22a, and one end of the compression coil spring 27 is supported. It has a flange 22c and a holding shaft 22d extending from the flange 22c on the side opposite to the shaft portion 22a and holding the magnet 24 in a state of being inserted. The bending amount F of the compression coil spring 27 is regulated by the tip of the holding shaft 22d protruding from the magnet 24 coming into contact with the lid member 14 of the case 12. This makes it possible to regulate the amount of deflection of the compression coil spring 27 with a simple configuration.

(5) A nut 26 and a washer 25 made of a magnetic material are adopted as a holding member for holding the magnet 24 between the flange 22c and the flange 22c. Therefore, the displacement of the rod member 22 can be detected more accurately than when the nut 26 and the washer 25 are made of a non-magnetic material.

<Second Embodiment>
The displacement detection device 200 according to the second embodiment of the present invention will be described with reference to FIG. Hereinafter, the points different from those of the first embodiment will be mainly described, and in the drawings, the same configurations as those described in the first embodiment or the corresponding configurations are designated by the same reference numerals and the description thereof will be omitted. ..

In the first embodiment, an example in which the nut 26 is screwed to the holding shaft 22d and the magnet 24 is sandwiched between the nut 26 and the flange 22c of the rod member 22 has been described (see FIG. 1). On the other hand, in the second embodiment, as shown in FIG. 5, the caulked portion 222g is formed by caulking the tip portion of the holding shaft 222d. A backing plate 225 formed of a magnetic material is arranged between the caulked portion 222 g and the magnet 24. The magnet 24 is fixed to the holding shaft 222d in a state of being sandwiched between the crimped portion 222g and the flange 222c of the rod member 222.

In the first embodiment, the tip of the holding shaft 22d of the rod member 22 comes into contact with the lid member 14 of the case 12, so that the amount of deflection of the compression coil spring 27 is restricted (see FIG. 1). .. On the other hand, in the second embodiment, the compression coil spring 27 is bent by abutting the stopper member 230 provided on the accommodating portion 212c of the case body 220 with the step portion 222j provided on the flange 222c of the rod member 222. The amount is regulated. That is, in the first embodiment, the lid member 14 of the case 12 is in contact with the rod member 22, whereas in the second embodiment, the stopper member 230 of the case 212 is in contact with the rod member 222. be. The step portion 222j of the rod member 222 is provided on the outer peripheral side of the step portion 22f that supports the end portion of the compression coil spring 27.

The accommodating portion 212c of the case body 220 is provided with a plurality of recesses 212h in the circumferential direction. The stopper member 230 is fitted into each recess 212h. The stopper member 230 is arranged so as to face the step portion 222j. The stopper member 230 is attached to the recess 212h after the rod member 222 is mounted on the accommodating portion 212c.

According to such a second embodiment, the same effects as those of (1) to (3) and (5) described in the first embodiment are obtained.

The following modifications are also within the scope of the present invention, and the configurations shown in the modifications may be combined with the configurations described in the above-described embodiments, or the configurations described in the above-mentioned different embodiments may be combined, and the following differences may occur. It is also possible to combine the configurations described in the modified example.

(Modification 1)
In the above-described embodiment, an example in which the nut 26, the washer 25, and the backing plate 225 are formed of a magnetic material has been described, but the present invention is not limited thereto. The nut 26, the washer 25, and the backing plate 225 may be formed of a non-magnetic material.

(Modification 2)
In the above-described embodiment, an example in which the lid member 14 is fixed to the case bodies 120 and 220 by a fastening member (not shown) such as a bolt has been described, but the present invention is not limited thereto. When a large force does not act on the lid member 14 such as when the pressure difference between the inside and the outside of the cases 12 and 212 is small, the lid member 14 is attached to the openings 12g of the case bodies 120 and 220 by press fitting or adhesion. May be good.

(Modification 3)
In the above-described embodiment, when the displacement detection devices 100 and 200 are attached to the hydraulic valve device 50 and when the displacement detection devices 100 and 200 are inspected, an external force acts on the rod members 22 and 222. However, the present invention has been described with respect to an example in which the amount of deflection F of the compression coil spring 27 is regulated so as not to exceed the allowable amount of deflection Fmax. Even if a large force is applied to the rod member 22 during the operation of the hydraulic valve device 50, the holding shaft 22d and the lid member 14 come into contact with each other, so that the amount of deflection F of the compression coil spring 27 is allowed. It is regulated not to exceed the amount Fmax. Similarly, even if a large force is applied to the rod member 222 during the operation of the hydraulic valve device 50, the step portion 222j of the flange 222c and the stopper member 230 come into contact with each other to cause the compression coil spring 27 to come into contact with each other. The deflection amount F is regulated so as not to exceed the allowable deflection amount Fmax.

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

The displacement detection devices 100 and 200 are arranged on the rod members 22, 222 that follow the spool 51 and displace, the compression coil springs 27 that urge the rod members 22, 222 toward the spool 51, and the rod members 22, 222. A magnet 24 that is displaced together with the rod members 22 and 222, cases 12 and 212 that accommodate the compression coil spring 27 and reciprocally support the rod members 22 and 222 in the displacement direction, and a magnetic field due to the displacement of the magnet 24. The magnet 24 is arranged inside the compression coil spring 27, and the case 12, 212 and the rod members 22, 222 come into contact with each other, whereby the magnet 24 and the case 12, 212 are provided. Prevents the magnet 24 from coming into contact with the magnet 24.

In this configuration, the magnet 24 is arranged inside the compression coil spring 27, and the cases 12, 212 and the rod members 22, 222 come into contact with each other to prevent the cases 12, 212 and the magnet 24 from coming into contact with each other. The space inside the compression coil spring 27 when the compression coil spring 27 is maximally bent can be effectively used as a space for arranging the magnet 24, and the magnet 24 is prevented from being damaged. As a result, the cases 12, 212 can be made smaller.

In the displacement detection devices 100 and 200, the deflection amount F of the compression coil spring 27 is regulated by the contact between the cases 12, 212 and the rod members 22, 222, and the deflection amount F of the compression coil spring 27 is the compression coil spring. It is regulated not to exceed the allowable deflection amount Fmax of 27.

In this configuration, when the displacement detection devices 100 and 200 are assembled to the hydraulic valve device 50 and when the displacement detection devices 100 and 200 are inspected, a large external force should be applied to the rod members 22 and 222. However, it is possible to prevent the compression coil spring 27 from exceeding the allowable deflection amount Fmax. As a result, the life of the compression coil spring 27 can be improved.

In the displacement detecting devices 100 and 200, the allowable deflection amount F of the compression coil spring 27 is 10% or more and 75% or less of the free length L0 of the compression coil spring 27.

In this configuration, since the allowable deflection amount Fmax of the compression coil spring 27 is 10% or more of the free length L0, the range of use of the compression coil spring 27 can be widened. Since the allowable deflection amount Fmax of the compression coil spring 27 is 75% or less of the free length L0, the deformation amount of the compression coil spring 27 can be suppressed and the life can be improved.

In the displacement detection device 100, the magnet 24 is formed in a cylindrical shape, and the rod member 22 has a shaft portion 22a whose tip abuts on the spool 51 and is slidably supported by the case 12, and the base end of the shaft portion 22a. It has a flange 22c that is provided in the above and supports one end of the compression coil spring 27, and a holding shaft 22d that extends from the flange 22c to the opposite side of the shaft portion 22a and holds the magnet 24 in a state of being inserted. The tip of the holding shaft 22d protruding from the magnet 24 comes into contact with the case 12, so that the amount of deflection of the compression coil spring 27 is restricted.

In this configuration, the bending amount F of the compression coil spring 27 is regulated by bringing the tip of the holding shaft 22d through which the magnet 24 is inserted into contact with the case 12, so that the compression coil spring 27 has a simple configuration. The amount of deflection F can be regulated.

The displacement detecting devices 100 and 200 further include a nut 26 and a washer 25, which are holding members for sandwiching the magnet 24 between the flanges 22c and 222c, and a backing plate 225, and the holding members such as the nut 26 and the washer 25, and the backing plate. 225 is made of a magnetic material.

In this configuration, by forming the nut 26, the washer 25, and the backing plate 225, which are the sandwiching members for sandwiching the magnet 24, with a magnetic material, the rod members 22, 222 are compared with the case where the sandwiching member is formed with a non-magnetic material. Displacement can be detected accurately.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiments. No.

12 ... Case, 22 ... Rod member (displacement member), 22a ... Shaft, 22c ... Flange, 22d ... Holding shaft, 24 ... Magnet, 25 ... Washer (pinching) (Member), 26 ... Nut (pinching member), 27 ... Compression coil spring, 32 ... Magnetic detection unit, 51 ... Spool (displacement detection target member), 100 ... Displacement detection device, 200 ... Displacement detection device, 212 ... Case, 222 ... Rod member (displacement member), 222c ... Flange, 222d ... Holding shaft, 225 ... Support plate (pinching member), 230.・ ・ Stopper member

Claims (5)

Displacement members that are displaced following the displacement detection target member, and
A compression coil spring that urges the displacement member toward the displacement detection target member, and
A magnet arranged on the displacement member and displaced together with the displacement member,
A case in which the compression coil spring is housed and the displacement member is reciprocally supported in the displacement direction, and a case.
A magnetic detection unit that detects a change in the magnetic field due to the displacement of the magnet is provided.
The magnetic detection unit is provided in the case and is provided.
The magnet is placed inside the compression coil spring.
A displacement detection device characterized in that the case and the displacement member are brought into contact with each other to prevent the case and the magnet from coming into contact with each other. In the displacement detection device according to claim 1,
When the case and the displacement member come into contact with each other, the amount of deflection of the compression coil spring is regulated.
A displacement detecting device, wherein the amount of deflection of the compression coil spring is regulated so as not to exceed the allowable amount of deflection of the compression coil spring. In the displacement detection device according to claim 2,
A displacement detecting device, wherein the allowable deflection amount of the compression coil spring is 10% or more and 75% or less of the free length of the compression coil spring. The displacement detection device according to any one of claims 1 to 3.
The magnet is formed in a cylindrical shape and has a cylindrical shape.
The displacement member is
A shaft portion whose tip abuts on the displacement detection target member and is slidably supported by the case.
A flange provided at the base end of the shaft portion and supporting one end of the compression coil spring, and
It has a holding shaft extending from the flange to the side opposite to the shaft portion and holding the magnet in a inserted state.
A displacement detection device characterized in that the amount of deflection of the compression coil spring is regulated by abutting the tip of the holding shaft protruding from the magnet against the case. In the displacement detection device according to claim 4,
Further, a holding member for holding the magnet between the flange and the flange is provided.
The displacement detecting device, wherein the sandwiching member is made of a magnetic material.

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