JP6621439B2 - Shut-off valve actuator - Google Patents

Description

  The present invention relates to a shut-off valve actuator used in a fluid shut-off device, and more particularly to a shut-off valve actuator using a stepping motor as a power source.

  Conventionally, a shut-off valve using a stepping motor as a power source is known as a shut-off valve used as a shut-off mechanism of a gas shut-off device (see, for example, Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 11-2351 JP 2014-231866 A

  In the technique described in Patent Literature 1, the volume of the magnet cannot be increased because the inner bush 12 that functions as a rear-side bearing is housed inside the rotor. In the technology of Patent Document 2, the volume of the magnet is increased because the lid 40 and a part of the bearing 39 mounted inside the lid 40 are housed inside the stator 36 and housed inside the rotor 43. I can't. By the way, not only the gas shut-off device but also this kind of technology requires the miniaturization of the entire device, and accordingly, the drive motor is also required to be miniaturized.

  In the situation where miniaturization is required in this way, in the techniques of Patent Document 1 and Patent Document 2 described above, since the stator diameter is limited, the volume of the rotor magnet cannot be increased, and the thrust of the motor is reduced. I can't make it bigger. That is, the thrust of the drive source that drives the shut-off valve cannot be increased.

  In such a background, an object of the present invention is to obtain a shut-off valve actuator that can obtain a large thrust even if it is downsized.

The present invention includes a rotor including a shaft and a magnet, a screw mechanism that converts rotation of the rotor into axial movement, a valve body that includes a valve portion and a movable plate that is movable in the axial direction by the screw mechanism, A front housing engaged with the movable plate so as to allow movement of the movable plate in an axial direction while preventing rotation of the movable plate; and a bearing for supporting the shaft in a rotatable state. The base of the housing and the bearing are adjacent to each other in the radial direction, and the magnet and the bearing are positioned so as not to overlap each other when viewed from the direction perpendicular to the shaft, and the movable plate protrudes in the direction of the front housing. The front housing includes a recess extending in the axial direction for accommodating the protruding portion of the movable plate, and the front housing is in a direction perpendicular to the axis. As seen from the above, it is a fluid shut-off valve actuator in which a part of the concave portion and the bearing overlap .

The present invention also provides a rotor including a shaft and a magnet, a screw mechanism that converts rotation of the rotor into axial movement, a valve body that includes a valve portion and a movable plate that is movable in the axial direction by the screw mechanism. A front housing engaged with the movable plate so as to allow movement of the movable plate in the axial direction while preventing rotation of the movable plate, and a bearing that supports the shaft in a rotatable state. The base of the front housing and the bearing are adjacent to each other in the radial direction, and the magnet and the bearing are positioned so as not to overlap each other when viewed from the direction perpendicular to the shaft. is shut-off valve actuator of the fluid located in the axial direction of the front housing by said front housing is in contact is determined

  According to the present invention, it is possible to obtain a shut-off valve actuator that can obtain a large thrust even if it is downsized.

It is sectional drawing of the gas cutoff apparatus to which the cutoff valve actuator of embodiment is applied. It is a top view of the cutoff valve actuator shown in FIG. It is sectional drawing of the cutoff valve actuator shown in FIG. It is the expanded sectional view which expanded a part of FIG.

(1) Structure of shut-off valve actuator FIG. 1 is a cross-sectional view of a gas shut-off device to which the shut-off valve actuator of the embodiment is applied. FIG. 2 is a plan view of the shut-off valve actuator shown in FIG. 3 is a cross-sectional view of the shut-off valve actuator shown in FIG. FIG. 4 is an enlarged cross-sectional view in which a part of FIG. 3 is enlarged.

  FIG. 1 shows a gas shut-off device 10. The gas cutoff device 10 has a housing 200 provided with gas flow paths 201 and 202. A valve seat 203 having an edge structure is provided between the gas flow paths 201 and 202. A valve rubber 315 that constitutes a valve portion that is driven in the left-right direction in FIG. 1 by the shut-off valve actuator 100 comes into contact with the valve seat 203, thereby shutting off (closing) the gas flow path. Further, when the valve rubber 315 is separated from the valve seat 203, the gas flow path is opened.

  The shut-off valve actuator 100 includes a PM stepping motor 300 that drives the valve rubber 315. The PM type stepping motor 300 has the same structure as a normal two-phase PM type stepping motor. The PM stepping motor 300 includes a two-phase stator 301 composed of a stator A and a stator B, and a rotor 304.

As shown in FIG. 3, the stator A includes a cup-shaped outer yoke 401 and a disk-shaped inner yoke 402. The cup-shaped outer yoke 401 has an opening in the center, and has a plurality of pole teeth extending in the axial direction (extending direction of the shaft 307) at the periphery of the opening. The disk-shaped inner yoke 402 has an opening in the center, and a plurality of pole teeth extending in the axial direction at the periphery of the opening. The pole teeth of the outer yoke 401 and the pole teeth of the inner yoke 402 are arranged so as to mesh with each other with a gap in the circumferential direction. A coil 404 wound around a resin bobbin 403 is disposed outside the pole teeth of the outer yoke 401 and the pole teeth of the inner yoke 402. The above is the structure of the stator A, but the stator B has the same structure as the stator A. A terminal block 406 having a circuit board 407 is fixed to the outer yoke 401 . A terminal pin 405 is embedded in the bobbin 403, and the terminal pin 405 protrudes outside from a notch formed in the outer yoke 401, and further penetrates the circuit board 407. A connector 408 to which wiring from the outside is connected is arranged on the circuit board 407. The connector 408 is connected to the terminal pin 405 by printed wiring on the circuit board 407.

  The stator 301 is configured by integrally forming the stator A and the stator B with resin (for example, PBT resin) in a state where the inner yokes of the stator A and the stator B are in contact with each other in the axial direction. When the stator A and the stator B are integrally formed of resin, a plurality of protrusions 323 are simultaneously integrally formed with resin on the upper surface of the stator A, and a rear bracket 301a is simultaneously integrally formed with the stator B side. This technique is described, for example, in paragraph “0067” of Japanese Patent Application Laid-Open No. 2004-169879.

  Inside the stator 301, a bottomed cup-shaped rotor case 302 made of a metal material (aluminum alloy, nonmagnetic stainless steel, etc.) is disposed. The bottomed cup-shaped rotor case 302 is closed on one side (the right side in FIG. 1), and a small diameter portion 302b is formed near the closed bottom. The other side (left side in FIG. 1) of the small-diameter portion 302b is an opening, and the periphery of the opening is provided with a flange portion 302a extending radially outward (see FIG. 3). A ball bearing 316 with a flange is mounted inside the small diameter portion 302b of the rotor case 302.

  A rotor 304 is rotatably disposed inside the rotor case 302. The rotor 304 includes a magnet 305, a sleeve 306, and a shaft 307. A cylindrical magnet 305 serving as a rotor magnet is attached to the outside of the sleeve 306, and the sleeve 306 is fixed to the shaft 307. A male screw is formed on the outer peripheral surface of one side (tip side) of the shaft 307, and a lead screw portion 308 is formed. The magnet 305 is multipolarized with N and S poles alternately in the circumferential direction. The shaft 307 is held in a freely rotatable state by ball bearings 303 and 316. A slight gap is provided between the outer periphery of the magnet 305 and the rotor case 302 so that the rotor 304 can rotate with respect to the rotor case 302.

  A metal front plate 309 is disposed on the upper surface of the stator A. When the stator A and the stator B are integrally formed of resin, a plurality of protrusions 323 are simultaneously integrally formed of resin on the upper surface of the stator A. The positions of the front plate 309 are determined by inserting the protrusions 323 through the through holes formed in the front plate 309, respectively.

As shown in FIG. 4, the outer ring of the ball bearing 303 has a flange portion 303 a, the front housing 311 is engaged with the flange portion 303 a, and the front housing 311 is further moved by the annular protrusion 310 a of the fixing plate 310. The front housing 311 is fixed to the outer ring of the ball bearing 303 by being pressed in the direction of the rotor 304 . The front housing 311 is made of a metal having a hollow cylindrical shape, and extends in a radially outward manner at one end side (the magnet 305 side), and is a disc shape serving as a base having a hole 311a formed at the center. The large-diameter portion 311d and a step portion 311c are provided.

  The front housing 311 is provided with a hole 311a extending in the axial direction. In this hole 311a, a pin 312a extending in the axial direction serving as a rotation preventing mechanism for the movable plate 312 is movable in the axial direction. Has been inserted. The hole 311a has a structure in which one end is closed, but may be a through hole. A ball bearing 303 with a flange 303a (see FIG. 4) is attached to the open end on one end side of the hollow portion of the front housing 311. By fitting the front housing 311 inside the rotor case 302, a coaxial state between the front housing 311 and the shaft 307 is secured.

  A metal fixing plate 310 is disposed on the upper surface of the front plate 309. The fixing plate 310 includes an annular protrusion 310a, and has a stepped hole in the center. The stepped hole has a through hole through which the front housing 311 is inserted and an annular recess 310d having a diameter larger than that of the through hole.

  The fixing plate 310 is placed on the upper surface of the front plate 309, and the inner edge of the annular protrusion 310 a of the fixing plate 310 is in contact with the stepped portion 311 c of the front housing 311. In this state, the fixing plate 310 is caulked and fixed to the front plate 309 at a position 321 (see FIG. 2). This caulking is performed by inserting a projection (not shown) formed on the fixing plate 310 into a through hole (not shown) formed on the front plate 309 and crushing the tip of the projection protruding from the front plate 309. Here, a not-shown through hole formed in the front plate 309 and a not-shown protrusion formed in the fixing plate 310 are outside the stator 301 when viewed from the axial direction, and the above-described caulking position 321 interferes with the stator 301. It has a structure that does not.

  When the fixing plate 310 is caulked and fixed to the front plate 309, an elastic ring (O-ring) 313 functioning as a shield ring disposed in the annular recess 310 d of the fixing plate 310 is formed between the flange portion 302 a of the rotor case 302 and the fixing plate 310. It is pressed and deformed in the axial direction by the annular protrusion 310a. Thereby, the space between the rotor case 302 and the fixing plate 310 is sealed. Further, the fixing plate 310 is formed with a hole 322 (see FIG. 2) for inserting a bolt (or a screw) to be attached to a device (not shown).

  The movable plate 312 is made of resin and includes a disk portion 312b and protrusions 312c and 312d that protrude from the disk portion 312b on both sides in the axial direction (see FIG. 3). The protrusion 312c has a through hole in the center, and a female screw 314 is formed on a part of the inner peripheral surface of the through hole. The protruding portion 312c on the side where the female screw 314 is formed is located in the hollow portion of the front housing, and the female screw 314 is screwed into the lead screw portion 308 of the shaft 307.

  In addition, a pin 312a extending in the axial direction is formed by integral molding from the disk portion 312b, and the movable plate 312 is inserted by inserting the pin 312a into a hole 311a formed in the front housing 311. Thus, a structure in which the rotation around the axis is prevented is obtained.

  The movable plate 312 is attached to the lead screw portion 308 by screwing the lead screw portion 308 of the shaft 307 and the female screw 314 of the movable plate 312. The valve body is composed of a movable plate 312 and a valve rubber 315 attached to the movable plate 312. The disc portion 312b of the movable plate 312 is mounted with a valve rubber 315 covered. The valve rubber 315 is made of, for example, NBR rubber. The shaft 307 is rotatably supported by a ball bearing 316 attached to the inside of the small diameter portion 302 b of the rotor case 302 and a ball bearing 303 attached to the inside of the front housing 311, and the rotor 304 is supported with respect to the rotor case 302. It can be rotated. Between the rear side ball bearing 316 and the sleeve 306 of the rotor 304, and between the front side ball bearing 303 and the sleeve 306 of the rotor 304, a resin washer (polyslider) is provided to improve sliding performance. 317 and 318 are interposed. A coil spring 319 is interposed between the movable plate 312 and the fixing plate 310 by being compressed. The coil spring 319 biases the valve rubber 315 toward the valve seat 203 when the valve rubber 315 contacts the valve seat 203 (see FIG. 1) and closes the fluid path.

(2) Operation of the shut-off valve actuator When an abnormality occurs, the coil 404 of the stator 301 is energized by an external input from a battery or the like to rotate the rotor 304 forward and the lead screw 308 rotates forward (the valve rubber 315 contacts the valve seat 203). Rotate in the direction of contact). Here, since the pin 312a serving as a rotation prevention mechanism formed on the movable plate 312 is inserted into the hole 311a of the front housing 311, the rotation of the movable plate 312 screwed with the lead screw portion 308 is prevented, and the above-described The forward rotation of the lead screw part 308 is converted into a linear motion of the movable plate 312, and the valve rubber 315 advances toward the valve seat 203. Finally, when the valve rubber 315 comes into contact with the valve seat 203, the gas paths 201 and 202 are closed, and the gas flow path is blocked.

  When the flow path is opened from the state where the flow path is blocked, the rotor 304 is rotated in the opposite direction to the above, and the movable plate 312 is moved in the reverse direction. By moving the movable plate 312 in the opposite direction, the valve rubber 315 is separated from the valve seat 203, the gas flow path is opened, and the gas supply is resumed.

  An elastic ring (O-ring) 313 disposed in the annular recess 310d of the fixing plate 310 is axially pressed and deformed by the flange 302a of the rotor case 302 placed on the upper surface of the front plate 309 and the fixing plate 310. Thus, the space between the rotor case 302 and the fixing plate 310 is sealed. For this reason, fluid (gas) pressure is applied to the inside of the rotor case 302, but airtightness between the rotor side and the atmosphere side is ensured by the elastic ring (O-ring) 313. The fluid is not limited to gas but may be liquid.

(3) Superiority In the shut-off valve of Patent Document 2, a part of the bearing 39 attached to the inside of the lid 40 and the lid 40 enters the inside of the stator 36 and enters the inside of the rotor 43. For this reason, the thickness of a rotor magnet cannot be ensured under the condition where the diameter is limited, and the volume of the rotor magnet is sacrificed.

  In contrast, in the structure of FIGS. 1 to 4, the front housing 311 has a hollow cylindrical shape, and a ball bearing 303 with a flange 303 a is attached to the open end of the hollow one end. . The ball bearing 303 is positioned inside a hollow cylindrical front housing 311, and the front housing 311 is positioned in the axial direction using a flange 303 a of the ball bearing 303. The lower end surface of the ball bearing 303 and the lower end surface of the front housing 311 are substantially the same height (substantially the same axial position). For this reason, the front housing 311 and the ball bearing 303 do not enter either the inside of the stator 301 or the inside of the rotor 304. Therefore, even when the diameter of the stator 301 is defined (limited), the volume of the magnet 305 can be secured and the thrust of the motor can be increased. Further, the strength of the magnet 305 is increased, and the magnet 305 is hardly cracked.

  As described above, the shut-off valve actuator 100 includes (1) the rotor 304 including the shaft 307 and the magnet 305, and (2) the seed screw portion 308 that constitutes a screw mechanism that converts the rotation of the rotor 304 into axial movement. And a female screw 314, (3) a valve body comprising a valve portion and a movable plate 312 movable in the axial direction by the screw mechanism, and (4) moving the movable plate 312 in the axial direction while preventing the movable plate 312 from rotating. A front housing 311 engaged with the movable plate 312 and (5) bearings 303 and 316 for supporting the shaft 307 in a rotatable state. The large diameter portion 311d serving as the base portion of the front housing 311 and the bearing 303 are adjacent to each other in the radial direction, and the magnet 305 and the bearing 303 are not overlapped when viewed from the direction perpendicular to the axis.

  According to this structure, since the bearing 303 and the large-diameter portion 311d of the front housing 311 overlap in the radial direction and the rotor 304 is not positioned on the outer side in the radial direction of the bearing 303, a large volume of the magnet 305 can be secured.

  Further, in the above configuration, (6) the front housing 311 includes a hole 311a that is a concave portion extending in the axial direction for accommodating the pin 312a of the movable plate 312, and the hole 311a is seen from a direction perpendicular to the axis. A part of the bearing 303 and the bearing 303 overlap each other. Here, it is also possible to make it the recessed part which penetrated the hole 311a to the axial direction.

  In order to ensure the movable range of the movable plate 312, the axial length of the hole 311a (hole depth) needs to be secured to some extent. On the other hand, downsizing of the cutoff valve actuator 100 in the axial direction is also required. In the structure of (6) above, the hole 311a and the bearing 303 are positioned so as to overlap each other in the radial direction, so that a large depth of the hole 311a can be secured while shortening the axial dimension.

  In addition to the configurations (1) to (6) above, (7) the bearing 303 includes a flange 303a on the outer periphery, and the large diameter portion 311d of the front housing 311 contacts the flange 303a so that the shaft of the front housing 303a The position in the direction is determined. According to the configuration of (7), the front housing 311 is reliably fixed in a structure in which an increase in the axial dimension is suppressed while ensuring the depth of the hole 311a.

DESCRIPTION OF SYMBOLS 10 ... Gas shut-off device, 100 ... Shut-off valve actuator, 200 ... Housing, 201, 202 ... Gas flow path, 203 ... Valve seat, 300 ... PM type stepping motor, 301 ... Stator, 301a ... Rear bracket, 302 ... Rotor case , 302a ... flange portion, 302b ... small diameter portion, 303 ... ball bearing, 303a ... flange, 304 ... rotor, 305 ... magnet, 306 ... sleeve, 307 ... shaft, 308 ... lead screw portion, 309 ... front plate, 310 ... fixed Plate, 310a ... annular projection, 310d ... annular recess, 311 ... front housing, 311a ... hole, 311c ... stepped portion, 312 ... movable plate, 312a ... pin, 312b ... disc part, 312c ... projection, 312d ... projection Part, 313 ... elastic ring, 314 ... female screw, 315 ... Rubber, 316 ... Ball bearings, 317, 318 ... Resin washers, 319 ... Coil spring, 321 ... Caulking position, 322 ... Hole, 323 ... Projection, 401 ... Outer yoke, 402 ... Inner yoke, 403 ... Bobbin, 404 ... Coil, 405, terminal pin, 406, terminal block, 407, circuit board, 408, connector.

Claims (2)

A rotor with a shaft and a magnet;
A screw mechanism that converts rotation of the rotor into axial movement;
A valve body comprising a valve plate and a movable plate movable in the axial direction by the screw mechanism;
A front housing engaged with the movable plate so as to allow movement of the movable plate in the axial direction while preventing rotation of the movable plate;
A bearing that supports the shaft in a rotatable state;
The base of the front housing and the bearing are adjacent in the radial direction;
When viewed from the direction perpendicular to the shaft, the magnet and the bearing do not overlap each other,
The movable plate includes a protrusion that protrudes in the direction of the front housing,
The front housing includes an axially extending recess that accommodates the protruding portion of the movable plate,
A fluid shut-off valve actuator in which a part of the recess overlaps with the bearing when viewed from a direction perpendicular to the shaft . A rotor with a shaft and a magnet;
A screw mechanism that converts rotation of the rotor into axial movement;
A valve body comprising a valve plate and a movable plate movable in the axial direction by the screw mechanism;
A front housing engaged with the movable plate so as to allow movement of the movable plate in the axial direction while preventing rotation of the movable plate;
A bearing that supports the shaft in a rotatable state;
With
The base of the front housing and the bearing are adjacent in the radial direction;
When viewed from the direction perpendicular to the shaft, the magnet and the bearing do not overlap each other,
The bearing has a flange on the outer periphery,
A fluid shut-off valve actuator in which a position of the front housing in the axial direction is determined by contacting the front housing with the flange.

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