JP3485992B2 - Spool valve device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, a hydraulic excavator,
The present invention relates to a spool valve device applied to a construction machine such as a hydraulic crane, and more particularly to a spool valve device including a spool position detection mechanism that detects a spool position.

[0002]

2. Description of the Related Art Generally, a spool valve device has a casing having a spool sliding hole formed therein, a spool slidably provided in the spool sliding hole of the casing, and the spool is constantly biased to an initial position. And a driving means such as a hydraulic pilot portion for slidingly displacing the spool against the biasing means, an electromagnetic actuator or a manual lever.

The casing is provided with a plurality of fluid passages that open into the spool slide holes, and the pressure and flow rate of the fluid can be controlled by displacing the spool in the spool slide holes in the axial direction. The distribution route (flow direction) of is switched.

Some of the spool valve devices are provided with a spool position detecting mechanism for detecting the sliding position of the displaced spool in order to control the fluid with high accuracy. For example, June 1990. It is known by "Introduction to Sensor Technology for Mechanical Engineers" (author Kiyoto Sano, Publisher Nikkan Kogyo Shimbun, pages 17-23) published on the 15th.

Here, as a spool position detecting mechanism according to the prior art of this kind, a primary side coil and a secondary side coil which are provided outside the casing and coaxially with the spool, and one end side thereof is fixed to the spool, 2. Description of the Related Art A differential transformer having a movable shaft that is slidably protruded from the casing at the other end and serves as a core for each coil is widely used.

In this spool position detecting mechanism, when the moving shaft is displaced in the axial direction together with the spool, the core of the moving shaft moves (displaces) in each coil, thereby causing a voltage change in the secondary coil. The sliding position of the spool is detected from this voltage change.

[0007]

By the way, in the above-described conventional spool valve device, the spool position detecting mechanism is provided outside the casing, and the displacement of the spool is taken out through the moving shaft to the outside of the casing. However, there is a problem in that the coils, the core of the moving shaft, and the like project out of the casing, and the spool valve device becomes large in size.

Further, since the displacement of the spool is taken out of the casing through the moving shaft, it is necessary to provide a seal member between the moving shaft and the end portion of the casing, which is not suitable for long-term use. When the seal member is worn, there is a problem that fluid such as oil liquid leaks out of the casing, and the leaked oil or the like damages each coil or the like to shorten the life.

The present invention has been made in view of the above-mentioned problems of the prior art. The displacement of the spool can be accurately detected over a long period of time, the durability and the life can be greatly extended, and the entire structure can be made compact. It is an object of the present invention to provide a spool valve device that can be formed and can be downsized.

[0010]

In order to solve the above-mentioned problems, a spool valve device adopted by the present invention has a casing having a spool sliding hole inside, and a sliding inside the spool sliding hole of the casing. It comprises a spool that can be provided and a spool position detection mechanism that detects the sliding position of the spool.

The feature of the configuration adopted by the invention of claim 1 is that the spool position detecting mechanism always urges the spool toward the initial position, and a spring force is generated in accordance with a sliding displacement of the spool. The changing spring member and the spool
The spool is provided in the casing at a distance from the spool.
A datum arranged to face the spring member in the axial direction of the sliding hole.
Between the ear diaphragm and the diaphragm and the spring member
The diaphragm is pressed and displaced by abutting against the diaphragm according to the spring force of the spring member.
And a pressing member provided on one side surface of the diaphragm,
A strain gauge for detecting the displacement of the diaphragm by the pressing member.
It is composed of

[0012]

According to a second aspect of the present invention , the pressing member is formed as a large-diameter adapter that receives the spring force of the spring member, and the tip end side of the adapter abuts against the diaphragm. It has a configuration providing a small diameter of the pressing protrusion for pressing displaced.

Further, according to the invention of claim 3 , in the diaphragm, the central portion with which the pressing member abuts is a thick portion, the outside of the thick portion is formed as an annular thin portion, and the thin portion is formed. are a configuration of providing the strain gauge.

[0015]

When the spool is slidably displaced, the spring member expands and contracts according to the displacement of the spool to change the spring force. And spool position detection
Mechanism, the spring force of ne member if by the sliding displacement of the spool
But it changes Then, the pressing force of the diaphragm by the pressing member
Since it changes, the displacement of the diaphragm can be detected with a strain gauge.
From the strain gauge and the electric signal corresponding to the spring force of the spring member.
No. is output, and the sliding position of the spool can be detected by this electric signal .

[0016]

Further, the configuration of the invention of claim 2, the spring force of the spring member is nest with large diameter of the adapter, since the pressing force to the diaphragm in the small diameter of the pressing projections you action, large pressing displace said diaphragm Can be made.

Furthermore, the configuration of the invention of claim 3, since by abutment of the thick portion on the pressing member, by the pressing member <br/> Te to prevent the stress concentration in the thin portion occurs In addition to preventing damage to the thin portion, the displacement amount per unit area of the thin portion can be increased.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A spool valve device according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 4 as an example in which the spool valve device is used as a directional control valve for a hydraulic actuator.

First, FIGS. 1 to 3 show a first embodiment of the present invention.

In the drawing, reference numeral 1 denotes a spool valve device according to the present embodiment, and the spool valve device 1 is roughly composed of a casing 2, a spool 8 and a spool position detecting mechanism 9 which will be described later.

Reference numeral 2 denotes a cylindrical casing which forms an outer shell of the spool valve device 1. The inside of the casing 2 serves as a spool sliding hole 3, and one end of the spool sliding hole 3 has a step 2
A female screw portion 2B is formed through A. In addition, the casing 2 has a pump port 4 connected to a hydraulic pump.
A tank port 5 connected to the tank, an output port 6 connected to the hydraulic actuator, and a pilot port 7 connected to a pilot valve (neither shown).
Are formed to be separated from each other by a predetermined distance in the axial direction.
Reference numerals 5 and 6 open in the spool slide hole 3, and the pilot port 7 opens in a pilot chamber A, which will be described later, formed in the spool slide hole 3.

Reference numeral 8 denotes a spool that is slidably inserted in the spool sliding hole 3 of the casing 2 in the axial direction, and the spool 8 has an outer diameter substantially corresponding to the hole diameter of the spool sliding hole 3. It is formed in a cylindrical shape with dimensions, and a pair of annular grooves 8A, 8B are formed on the outer peripheral side thereof with a predetermined distance in the axial direction. Then, the spool 8 is slidably displaced in the spool sliding hole 3 in the direction of the arrow B to thereby form the annular groove 8
Connect the pump port 4 and the output port 6 through A,
The tank port 5 and the output port 6 are made to communicate with each other via the annular groove 8B by sliding displacement in the arrow C direction.

Reference numeral 9 denotes a spool position detecting mechanism provided on one end side of the casing 2, and the spool position detecting mechanism 9
Is a holder 10, a diaphragm forming member 11, which will be described later,
The strain gauge 12, the adapter 13, the coil spring 14 and the like are roughly configured.

Reference numeral 10 denotes a holder as a lid mounted on one end of the casing 2. The holder 10 has a large-diameter cylindrical portion 10A having a large diameter and a tapered lid from the large-diameter cylindrical portion 10A. Small-diameter cylindrical portion 10C extended to the other side via the portion 10B
And a large-diameter tubular portion 10C.
The portion between A and A is closed by a tapered lid portion 10B. The inner peripheral side of the large-diameter cylindrical portion 10A serves as a housing portion 10D that houses an amplifier 15 to be described later, and the outer peripheral side serves as a male screw portion 10E screwed to the female screw portion 2B of the casing 2.

As shown in FIG. 2, a fitting step portion 10F to which the diaphragm forming member 11 is attached is formed on the inner periphery of the tip end side of the small-diameter cylindrical portion 10C, and a radial oil hole is formed in the axially intermediate portion. 10G and 10G are drilled. And
The oil holes 10G are for constantly communicating the inside of the small-diameter cylindrical portion 10C with the pilot chamber A, and maintaining the inside of the small-diameter cylindrical portion 10C at the same pressure state as the pilot chamber A.

Reference numeral 11 denotes a diaphragm forming member attached to the tip side of the small-diameter cylindrical portion 10C of the holder 10. The diaphragm forming member 11 has a cylindrical portion 11A as shown in FIG.
A collar portion 11B located on the other end side of the tubular portion 11A and fitted into the fitting step portion 10F of the holder 10, and the tubular portion 11A.
And a thin disk-shaped diaphragm 11C provided so as to close one end side of the diaphragm 11C.
Is deformed by being pressed by the adapter 13.

Numeral 12 is a film-shaped strain gauge attached to one side surface of the diaphragm 11C. The strain gauge 12 detects the strain of the diaphragm 11C to obtain an electric power corresponding to the magnitude of the strain (strain amount). It outputs a signal. The strain gauge 12 constitutes displacement detecting means together with the diaphragm forming member 11 and the adapter 13.
The displacement of the spool 8 is detected as the displacement of the diaphragm 11C from the spring force of the coil spring 14. As the strain gauge 12, for example, a metal strain gauge, a semiconductor strain gauge, a pressure sensitive diode, a pressure sensitive transistor, or the like is used.

Reference numeral 13 denotes an adapter as a pressing member provided between the spool 8 and the diaphragm forming member 11 and provided in the spool sliding hole 3, and the adapter 13 receives the spring force of the coil spring 14. In order to do so, it is formed in a stepped disc shape, and a small-diameter pressing projection 13A is integrally formed at the center of one end side thereof. Here, the adapter 13 is movably arranged in the pilot chamber A, and the pressing projection 13A has its tip always in contact with the central portion of the diaphragm 11C. The adapter 13 is a coil spring 1
By receiving the spring force of No. 4, this spring force is amplified by the pressing projection 13A having a small diameter, and the diaphragm 11 when pressing the diaphragm 11C by the tip portion of the pressing projection 13A.
The configuration is such that the displacement amount (strain amount) of C is increased. Further, the adapter 13 is provided with an oil hole 13B axially formed therein for communicating the inside of the diaphragm forming member 11 with the pilot chamber A.

Here, the pilot chamber A is defined between the spool 8 and the diaphragm forming member 11, and pressure oil is supplied through the pilot port 7 to slide the spool 8 in the direction of arrow C. Dynamically displace. Further, on the other side of the spool 8, another pilot chamber (not shown) is defined so as to face the pilot chamber A, and pressure oil is supplied to the other pilot chamber to indicate the spool 8 in the direction of the arrow. When slidingly displaced in the B direction, the pressure oil in the pilot chamber A is discharged into the tank via the pilot port 7. The pilot chamber A, the pilot port 7, the other pilot chambers, and the like constitute a hydraulic pilot portion that serves as a driving unit.

Reference numeral 14 is a coil spring as a spring member disposed in the pilot chamber A and arranged between the spool 8 and the adapter 13.
Even when the spool 8 is constantly biased toward the neutral position (initial position) shown in FIG. 1 and is displaced from the neutral position in the directions of arrows B and C in FIG.
Is arranged in the pilot chamber A so that can be pressed. In the coil spring 14, the spool 8 has an arrow B,
When displaced in the C direction, the spring force increases or decreases according to the amount of displacement, and the spring force at this time is transmitted to the diaphragm 11C via the adapter 13.

Reference numeral 15 denotes an amplifier arranged in the housing portion 10D of the holder 10. The amplifier 15 has an input side connected to the strain gauge 12 via a plurality of signal lines 16, 16 ,.
The output side is connected to a control unit (not shown) outside the casing 2 via a plurality of lead wires 17, 17, .... In addition, each signal line 16 is cast in the middle part at the same time when the holder 10 is molded, so that the holder 10 reliably prevents the oil liquid from leaking from the periphery of each signal line 16. . And the amplifier 15 is
The electric signal input from the strain gauge 12 is amplified and output to the control unit.

Reference numeral 18 denotes a rubber stopper attached to the opening of the housing 10D of the holder 10 for preventing rainwater and the like from entering the housing 10D. Reference numeral 19 denotes the step 2A of the casing 2 and the holder 1.
The O-rings provided between the No. 0 lid portion 10B and the spool sliding hole 3 for preventing the oil liquid from leaking are shown.

The spool valve device 1 according to the present embodiment has the above-described structure, and by supplying pressure oil to another pilot chamber, the spool 8 slides in the direction of arrow B against the coil spring 14. When displacing, the pump port 4 is communicated with the output port 6 on the hydraulic actuator side by the annular groove 8A of the spool 8, whereby pressure oil from the hydraulic pump is supplied to the hydraulic actuator via the output port 6.

When pressure oil is supplied to the pilot chamber A through the pilot port 7 and the spool 8 is slidably displaced in the direction of arrow C, the annular groove 8B of the spool 8 causes the output port 6 on the hydraulic actuator side. Is communicated with the tank port 5, whereby the return oil from the hydraulic actuator is discharged into the tank via the tank port 5.

Next, the position detection of the spool 8 by the spool position detection mechanism 9 during the above operation will be described.

First, when the spool 8 is slidably displaced in the direction of arrow B, the coil spring 14 is compressed and deformed in accordance with the displacement amount of the spool 8, and the spring force of the coil spring 14 increases. Due to the increase in the force, the pressing protrusion 13A of the adapter 13 presses the diaphragm 11C of the diaphragm forming member 11 with a larger pressing force. Then, the small-diameter pressing protrusion 13A applies a large pressing force to the diaphragm 11C at its tip side, and the strain gauge 12 largely distorts and deforms the diaphragm 11C by the pressing force at this time, so that the strain gauge 12 changes the strain amount of the diaphragm 11C. The displacement of the spool 8 is detected, and the electric signal at this time is output to the control unit via the amplifier 15 and the like.

When the spool 8 is slidably displaced in the direction of arrow C, the coil spring 14 expands in accordance with the amount of displacement of the spool 8 and the spring force of the coil spring 14 becomes smaller. As a result, the pressing force of the pressing protrusion 13A of the adapter 13 on the diaphragm 11C becomes smaller. Then, the small-diameter pressing projection 13A gives a small pressing force to the diaphragm 11C at its tip side, and the strain gauge 12C deforms a little with the pressing force at this time, whereby the strain gauge 12 reduces the strain amount of the diaphragm 11C. The displacement of the spool 8 is detected, and the electric signal at this time is output to the control unit via the amplifier 15 and the like.

As a result, an electric signal corresponding to the displacement of the spool 8 can be output from the strain gauge 12, and the displacement position of the spool 8 can be detected based on this electric signal.

The spring force of the coil spring 14 is received by the large-diameter adapter 13 and transmitted to the diaphragm 11C via the small-diameter pressing protrusion 13A formed on the adapter 13, whereby the spring of the coil spring 14 is Since the force is transmitted to the diaphragm 11C in a state of being amplified by the pressing protrusion 13A having a small diameter, the diaphragm 11C can be largely displaced even when the fluctuation of the spring force is small.

Furthermore, since the oil holes 10G are formed in the small-diameter cylindrical portion 10C of the holder 10, the pressure oil in the pilot chamber A is introduced into the small-diameter cylindrical portion 10C.
The same pressure can be constantly applied to both sides of the diaphragm 11C, and the displacement of the diaphragm 11C due to the pilot pressure can be prevented.

Thus, according to this embodiment, the spool 8
The displacement of is converted into a spring force (pressing force) by the coil spring 14,
This is transmitted to the diaphragm 11C via the adapter 13, and the strain gauge 12 detects the strain deformation of the diaphragm 11C to output an electric signal according to the displacement amount of the spool 8 from the strain gauge 12. From this, the displacement position of the spool 8 can be detected based on the spring force of the coil spring 14, and it is not necessary to separately provide a moving shaft or the like for extracting the displacement amount of the spool as in the conventional technique, and the spool position detection mechanism 9 can be formed compactly and can be reduced in size and weight, and various spools 8 can be supported, and the applicable range can be greatly expanded.

By disposing the spool position detecting mechanism 9 in the spool sliding hole 3 of the casing 2, it is not necessary to provide a seal member or the like between the moving shaft and the casing as in the prior art, It is possible to reliably prevent pressure oil (oil liquid) in the spool sliding hole 3 from leaking to the outside due to sliding wear of the seal member, and it is possible to extend the durability and life of the spool position detecting mechanism 9. The reliability can be greatly improved.

Further, since the spring force of the coil spring 14 is received by the large-diameter adapter 13, and is transmitted to the diaphragm 11C via the small-diameter pressing projection 13A formed on the adapter 13, the coil spring 14 can be transmitted. Diaphragm 1 with the spring force of 14 being amplified by the small-diameter pressing protrusion 13A.
1C, the diaphragm 11C can be largely displaced even when the fluctuation of the spring force is small, and the detection accuracy can be greatly improved.

Further, since the coil spring 14 is brought into contact with the spool 8 and the displacement amount of the spool 8 is detected by the change of the spring force, the length, the spring constant, etc. of the coil spring 14 are appropriately changed. As a result, the measurement range can be easily expanded without increasing the axial dimension of the spool position detection mechanism 9.

On the other hand, the oil holes 10G formed in the small-diameter cylindrical portion 10C of the holder 10 can guide the pressure oil into the small-diameter cylindrical portion 10C to hold both sides of the diaphragm 11C at the same pressure. Diaphragm 1 by pilot pressure
It is possible to prevent erroneous detection due to displacement of 1C, and
The displacement amount of can be detected with high accuracy.

Next, FIG. 4 shows a second embodiment of the present invention. The feature of this embodiment is that the central portion of the diaphragm is made thick and the outer peripheral side thereof is made thin. In addition,
In this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 21 denotes a diaphragm forming member according to this embodiment. The diaphragm forming member 21 is substantially the same as the diaphragm forming member 11 described in the first embodiment. A flange portion 21B located on the other end side of the portion 21A and fitted into the fitting step portion 10F of the holder 10.
And a diaphragm 22 provided so as to close one end side of the cylindrical portion 21A.

However, in the diaphragm forming member 21, the diaphragm 22 has a disk-shaped thick portion 22A having a thick center portion so as to project toward the other side, and the thick portion 2
A cylindrical portion 21A extending radially outward from the outer periphery of 2A in a thin wall shape.
An annular thin-walled portion 22 provided so as to close the gap between
B, and the thick wall portion 22A has an adapter 13
The pressing protrusion 13A is brought into contact with.

Reference numeral 23 is a film-like strain gauge attached to one side surface of the diaphragm 22, and the strain gauge 23 is formed in an annular shape so as to correspond to the annular thin portion 22B.
When the thin portion 22B is distorted, an electric signal corresponding to the magnitude of this distortion (distortion amount) is output.

In this way, in this embodiment having the above-mentioned structure, it is possible to obtain substantially the same effect as the first embodiment described above, but in particular, in this embodiment, the pressing protrusion 13A of the adapter 13 is used. Since it is brought into contact with the thick portion 22A, it is possible to prevent the diaphragm 22 from being damaged by the pressing force from the small-diameter pressing protrusion 13A for a long period of time, and the reliability and the life can be greatly improved. Can be improved. Moreover, since the displacement amount per unit area of the thin portion 22B can be increased, the detection accuracy can be improved.

In the first embodiment, each oil hole 10G is formed in the small diameter cylindrical portion 10C of the holder 10, and the small diameter cylindrical portion 10C is formed.
Although it has been described that the pressure oil in the pilot chamber A is introduced into C, both sides of the diaphragm 11C are held at the same pressure. For example, as shown by the dotted line in FIG. 3, the cylindrical portion 11A of the diaphragm forming member 11 is described. Oil hole 3 that penetrates in the axial direction
By piercing 1, the pressure between the pilot chamber A side and the inside of the small diameter cylindrical portion 10C may be maintained at the same pressure.

Further, the spool 8 is described as being slidably displaced by supplying / discharging pressure oil to / from the pilot chamber A and other pilot chambers. However, for example, only the other pilot chamber is provided and the coil spring 14 is used for returning. It may be used as a spring of, and in this case, the pilot chamber A becomes a spring chamber, and the pilot port 7 becomes a drain port connected to the tank.

Further, in the embodiment, the hydraulic pilot portion composed of the pilot chamber A, the pilot port 7 and other pilot chambers is exemplified as the driving means for slidingly displacing the spool 8. However, for example, an electromagnetic actuator, a manual lever or the like is used. Other driving means may be applied.

On the other hand, although the spool valve device 1 is exemplified as the switching valve for selectively switching the hydraulic actuator, the hydraulic pump, and the tank, the spool valve device 1 is not limited to this, and other spools such as a pressure control valve and a flow control valve may be used. It may be applied to a valve device.

[0056]

As described in detail above, according to the first aspect of the invention, when the spool is slid and displaced, the spring member is expanded and contracted according to the displacement of the spool to change the spring force, thereby changing the spool position. Detection mechanism is diaphragm, pressing member
And depending on the strain gauges, by taking out a change in the spring force of the spring member, Ru can detect the sliding position of the spool from the spring force. Therefore , it is not necessary to separately provide a moving shaft or the like for taking out the displacement amount of the spool as in the prior art, the spool position detection mechanism can be formed compactly, and the spool valve device can be reduced in size and weight. In addition, it is possible to support various spools and expand the applicable range.

In this case, the pressing portion of the spool position detecting mechanism
The material comes into contact with the diaphragm so that the spring member
Order to press displacing the diaphragm in response to the root force, when the spring force of the spring member is changed by sliding displacement of the spool varies the pressing force of the diaphragm by the pressure member
It is to be able, with the displacement amount of the diaphragm can be detected by strain gauges, by outputting an electrical signal corresponding to the spring force from the strain gauge can detect the slide position of the spool by the electric signal .

According to the second aspect of the invention, the spring force of the spring member is received by the large-diameter adapter, and a pressing force of the small-diameter pressing projection acts on the diaphragm, whereby the diaphragm is largely pressed and displaced. Because you can
The detection accuracy of the strain gauge can be improved.

Further, according to the invention of claim 3 , the diamond is
Because they are brought into contact with the thick portion of the fram the pressing member, the pressing
It is possible to prevent stress concentration on the thin part of the diaphragm by the member , prevent damage to the thin part for a long period of time, and extend the durability and life, and also the displacement of the thin part per unit area. Since the amount can be increased, the detection accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a spool valve device according to a first embodiment.

FIG. 2 is an enlarged vertical cross-sectional view of essential parts showing a spool position detection mechanism and the like in FIG.

FIG. 3 is an enlarged vertical sectional view showing a diaphragm forming member and a strain gauge in FIG.

FIG. 4 is an enlarged vertical sectional view showing a diaphragm forming member and a strain gauge according to a second embodiment.

[Explanation of symbols]

1 Spool valve device 2 casing 3 Spool sliding hole 8 spools 9 Spool position detection mechanism 11,21 Diaphragm forming member 11C, 22 diaphragm 12,23 Strain gauge (displacement detection means) 13 Adapter (pressing member) 13A pressing protrusion 14 Coil spring (spring member) 22A thick part 22B Thin part

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Ohira 650, Jinrachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura factory (56) References JP-A-8-14435 (JP, A) JP-A-5 -147895 (JP, A) Actually opened 62-156682 (JP, U) Actually opened 62-174184 (JP, U) Actually opened 62-203404 (JP, U) Actually opened 62-163678 (JP, U) ) International publication 90/001153 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 3/00-3/36 F16K 37/00

Claims (3)

(57) [Claims] 1. A casing having a spool sliding hole inside thereof, a spool slidably provided in the spool sliding hole of the casing, and a spool position detecting mechanism for detecting a sliding position of the spool. in the spool valve device comprising, prior Symbol spool position detection mechanism, spaced a pre-Symbol spool normally urged toward the initial position, a spring member the spring force is changed according to the sliding displacement of the spool from the spool Installed in the casing
Facing the spring member in the axial direction of the spool sliding hole
And a diaphragm disposed between the diaphragm and the spring member.
The spring force of the spring member is brought into contact with the earflam.
A pressing member for pressing and displacing the diaphragm according to the above, and the pressing member provided on one side surface of the diaphragm.
A spool valve device comprising a strain gauge for detecting displacement of a diaphragm caused by the spool valve device. 2. The pressing member is formed as a large-diameter adapter that receives the spring force of the spring member, and the adapter has a small-diameter pressing projection that abuts the diaphragm at its tip end side and presses and displaces the diaphragm. the formed by providing claim 1
The spool valve device described in 1. 3. The diaphragm is configured such that a central portion with which the pressing member abuts is a thick portion and an outer side of the thick portion is an annular thin portion, and the strain gauge is provided in the thin portion. The spool valve device according to claim 1 or 2 .