JP2004347021A - Cut-off valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cut-off valve capable of simultaneously realizing high reliability of airtightness, stable operating performance with small power, operation durability, and economic efficiency. <P>SOLUTION: The rear part of a rotor directly supports a rotating shaft 69 to which surface treatment for reducing contact resistance is applied by the inside pan-like part 66c of a partition wall 66. The front part of the rotor forms a recessed part 72b formed in a metal plate cover 72 and a small diameter groove 69b formed in a metal rotating shaft 69, and a plurality of metal balls 75 form radial and thrust bearings 76 to hold the axis of the rotor 71. Since the coefficients of linear expansion of the rotating shaft 69 and a holding side are generally made equal to each other, the possibility of locking due to a variation in temperature can be lowered, a minimum radial clearance can be set, the accuracy of the axis of the rotor 71 can be increased, stable operating performance with reduced power can be realized, and high operating durability can be realized by the rolling. Since the cut-off valve in simple structure is formed, high economic efficiency can be realized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a safety valve (International Patent Class F16K 17/36) using an electric motor as an operating means (International Patent Class F16K 31/04), particularly a gas shut-off device for preventing a gas accident from occurring. More specifically, the present invention relates to a shutoff valve used as a shutoff mechanism, and more specifically, a motor that performs a shutoff return operation of a flow passage by moving a valve body forward or backward with respect to a valve seat formed in the flow passage as a power source. Related to the shut-off valve.
[0002]
[Prior art]
Conventionally, various safety devices have been used to prevent gas accidents.In particular, when the gas flow rate is monitored by a built-in gas meter and the flow rate sensor is monitored and the microcomputer determines that the gas usage status is abnormal, Monitors the status of sensors such as seismic sensors, gas pressure sensors, gas alarms, and carbon monoxide sensors, and when it is judged that there is a danger, shuts off the gas with a shut-off valve built into the gas meter. 2. Description of the Related Art Gas meters with built-in shut-off devices (hereinafter referred to as microcomputer meters) have been promoted due to their advantages such as safety, ease of gas piping, and low price, and have been spread to almost all households.
[0003]
In addition, the ratio of centralized monitoring microcomputer meters that have a telemeter function that centrally monitors gas flow rate information measured by a flow rate sensor using a telephone line, etc., has also increased, making it more convenient and reliable as an information terminal. Improvement is required.
[0004]
In this centralized monitoring type microcomputer meter, gas can be shut off and gas returned by electric energy from the battery mounted on the microcomputer meter so that gas can be shut off and reset by simple electric switch operation or remote operation by telephone line etc. In order to maintain the open state and the closed state, a shut-off valve that does not require energy is required.
[0005]
Conventionally, as a driving method of the shut-off valve, a method using an electromagnetic solenoid has been mainly used. In recent years, a PM type stepping motor capable of realizing a relatively strong closing force and a returning force and capable of maintaining a state when power is not supplied has been developed. Shut-off valves that use a drive source are attracting attention, and shut-off valves that have airtight partitions with the rotor inside the gas flow path and the stator outside the gas flow path are attracting attention because they can be easily attached to the gas flow path. Have been.
[0006]
Hereinafter, a conventional shutoff valve will be described.
[0007]
2. Description of the Related Art Conventionally, shut-off valves using a PM type stepping motor of this type as a driving source have been disclosed (for example, see Patent Documents 1 and 2).
[0008]
As shown in FIG. 3, the shut-off valve described in Patent Document 1 has a cup-shaped casing 6 with a flange formed by aluminum impact molding or the like serving as an airtight partition, and a stator 4 is mounted on the outer periphery of the casing 6. An outer bush 3 which is a radial sliding bearing made of self-lubricating synthetic resin such as polyacetal is fitted into the opening of the casing 6, and the stud 5 is eccentrically integrated with the outer bush 3 so as to move forward. An inner bush 12, which is a radial sliding bearing made of a self-lubricating synthetic resin such as polyacetal, is inserted into the casing 6, and a lead screw 17 is attached to the outer bush 3 and the inner bush. With the male screw portion 17a protruding forward from the outer bush 3, the male screw portion 17a is rotatably supported in the forward and reverse directions. A rotor 16 is attached to the lead screw 17 so as to face the stator 4, and three or more balls 19 are circumferentially placed between two washers 20 and 21 disposed between the rotor 16 and the outer bush 3. A first thrust load rolling bearing 18 arranged above is interposed, and a second thrust load rolling bearing 24 similarly constructed between the rotor 16 and the inner bush 12 is interposed. A spring seat washer-like elastic expansion / contraction member 30 is interposed between the thrust load rolling bearing 24 and the inner bush 12, and the valve seat holding member 26 engages with the stud 5 and is screwed into the male screw portion 17a. 27 is disposed.
[0009]
A disk-shaped stepped flange 2 is fitted on the outer periphery of the outer bush 3, and an annular flat plate flange 7 to which the stator 4 is welded is fitted on the outer periphery of the casing 6. The stepped flange 2 and the flat plate flange 7 are fixed to each other and simultaneously sandwich the flange of the outer bush 3 and the flange of the casing 6. Further, between the stepped flange 2 and the flat plate flange 7, an elastic sealing member 8 made of an elastic synthetic resin and having a circular cross section is assembled in a state pressed in the front-rear direction.
[0010]
The operation of the shut-off valve configured as described above will be described below.
[0011]
At the time of abnormal use of gas or the like, the rotor 16 is rotated in the forward direction by energization from a control unit (not shown), the lead screw 17 rotates in the forward direction, and the valve body 25 moves from the lead screw 17 side to the valve seat 28 side. To abut against the valve seat 28 to close the flow path and shut off the fluid. When the valve is returned, the lead screw 17 is rotated in the reverse direction by energization from the control unit, the valve body 25 is retracted from the valve seat 26 side to the lead screw 17 side, the flow path is opened, and the fluid is opened. Supply was resumed.
[0012]
This type of shut-off valve is disposed in the flow passage so as to urge the fluid pressure of gas or the like in the valve closing direction. However, since the first thrust load rolling bearing 18 receives a thrust load, torque loss as a frictional force is reduced.
[0013]
FIG. 4 shows a shut-off valve described in Patent Document 2. This shut-off valve also has substantially the same configuration as the shut-off valve of FIG. 3, except that there is no inner bush or outer bush which is a radial slide bearing, and a rolling bearing 44 disposed on a lead screw 50 of the rotor 42, Reference numeral 45 denotes a generally distributed radial ball bearing whose position is regulated by a flange 46, which is a metal plate welded to both ends of the stator 41, and a rear cover 47. The airtight partition is not a cup-shaped casing but both ends are open. In that the seal members 48 and 49 are disposed between both ends of the pipe 43 and the flange 46 and the rear cover 47, and the stud 53 is press-fitted and fixed to the flange 46 by a metal bar having a header. is there.
[0014]
The rolling bearings 44 and 45 can also receive a thrust load, and can reduce torque loss as a frictional force at the time of valve opening or the like.
[0015]
The operation of the shut-off valve is the same as that of the shut-off valve in FIG.
[0016]
[Patent Document 1]
JP-A-11-2351 (page 4-5, FIG. 1)
[Patent Document 2]
JP-A-9-210237 (page 3-5, FIG. 4)
[0017]
[Problems to be solved by the invention]
The shut-off valve using a PM type stepping motor of this type as a drive source is required to maintain the axis of the rotor and to ensure coaxiality with the airtight partition for stable operation performance and low power.
[0018]
In addition, since it is attached to a gas meter generally installed outdoors, a severe temperature environment change from a high temperature exceeding 50 ° C. to a low temperature below −20 ° C. is applied. In addition, since the gas is attached to the gas flow path, it is exposed to refined impurities such as fuel gas and water, hydrogen sulfide, and sulfur dioxide that are slightly contained in the gas. Among them, high airtight reliability is required to prevent gas leakage during the service period of the gas meter (generally 10 years).
[0019]
That is, it is necessary to achieve both rotor shaft center holding accuracy and high airtight reliability.
[0020]
However, in the conventional shut-off valve shown in FIG. 3, the outer bush 3 which is a radial sliding bearing made of synthetic resin and the inner bush 12 position the lead screw 17 which is the rotating shaft in the radial direction. Since the difference in linear expansion coefficient between the metal lead screw 17 and the metal lead screw 17 is large, it is necessary to set the hole diameter large so as not to lock the lead screw 17 at a low temperature. As a result, the outer bush 3, the inner bush 12 and the lead screw 17 The radial clearance is large, and the self-lubricating synthetic resin such as polyacetal has a high molding shrinkage and it is difficult to increase the dimensional accuracy during molding. Had a problem of becoming low.
[0021]
Further, there is a problem that the cost is increased due to the complicated structure of the rolling bearing in the thrust direction and the sliding bearing made of the resin in the radial direction both before and after the support of the lead shaft.
[0022]
Further, in the conventional shut-off valve shown in FIG. 4, the axial center of the rotor 16 is held by the flange 46 made of a metal plate, the rear cover 47, and the radial rolling bearings 44, 45. And the radial clearance can be reduced, but on the other hand, the axial center is determined by the accuracy of the welding performed by positioning the flange 46, the rotor 41, the rear cover 47 and many parts, and the welding process is performed simultaneously with the pipe. Since this is also a process for maintaining the airtightness between the flange 43, the flange 46, and the rear cover 47, careful attention must be paid to manufacturing, and the cost is further increased.
[0023]
At the same time, since there are two sealing locations, that is, the sealing members 48 and 49, there is a problem that the airtight reliability is reduced.
[0024]
In the shut-off valve shown in FIG. 4, the surface of the welded portion 54 between the flange 46 and the stator 41 on the flow path side is in gas, and the other surface is in air, so that the fuel gas, moisture contained in the gas, hydrogen sulfide, etc. However, it is simultaneously exposed to severe conditions such as temperature changes in an organic substance environment such as active gas which is a purified impurity such as sulfur dioxide, outdoor high temperature and high humidity environment close to saturation humidity, and dew condensation in a gas meter. There is a problem that the strain remains between the metal structures to cause intergranular corrosion and stress corrosion cracking, which may cause a fracture. If the welded portion 54 is broken, gas leakage may occur.
[0025]
At the same time, since there are two sealing locations, that is, the sealing members 48 and 49, there is a problem that the airtight reliability is reduced.
[0026]
Further, in the shut-off valve of FIG. 4, since expensive radial rolling bearings are used as the bearings 44 and 45, there is a problem that the whole becomes further expensive.
[0027]
In view of such conventional problems, the present invention has high airtight reliability capable of withstanding stress such as humidity, temperature, and chemical substances in long-term use, stable operation performance with low power due to high rotor shaft center holding accuracy, and high performance. An object of the present invention is to provide a shut-off valve capable of simultaneously realizing operation durability and economy with a simple structure.
[0028]
[Means for Solving the Problems]
In order to solve the conventional problems, the support of the rear part of the rotor, which does not receive a relatively large thrust load, narrows the bottom of the metal partition wall in two steps, performs surface repair to reduce friction on the surface of the rotating shaft, Is directly supported by a metal partition.
[0029]
In addition, a metal lid having a hole through which the rotating shaft can penetrate is provided coaxially at the center of the open end of the metal partition wall formed in a pot shape without a through hole for supporting the front portion of the rotor. And coaxially disposed between the rotor and the rotor to support the axial center of the rotor, and to dispose and support a shared radial / thrust rolling bearing for supporting the axial load between the lid and the rotor.
[0030]
As described above, the rear part of the rotor does not intervene with a resin part that simply inserts a metal rotary shaft that has been subjected to a surface treatment to reduce contact resistance in a two-stage drawn part provided by drawing on a metal partition wall. Due to the simple structure between the metals, a bearing structure with a high axial center accuracy that can set a small radial clearance with a small linear expansion coefficient is obtained.
[0031]
In addition, the front part of the rotor supports the axial center of the rotor with a metal partition, a metal lid, and a radial / thrust shared rolling bearing, so that the linear expansion coefficient of the metallic rotating shaft is almost equal to that of the metallic rotating shaft. The possibility of locking and the like is low, the minimum radial clearance can be set, the accuracy of the axial center of the rotor at the partition open end side is increased, and stable operation performance with low power can be realized.
[0032]
Since there is no through hole in the partition and the inside and outside of the partition can be sealed with one seal member, high hermetic reliability with few failure parts can be realized.
[0033]
In addition, since the shaft center of the rotor is completed when the partition and lid are assembled by inserting a rolling bearing for both radial and thrust, the stator and flange must be fixed using a relatively low-precision machining method such as caulking. Thus, a reduction in material strength due to welding can be prevented, and high airtight reliability and economic efficiency that do not lead to gas leakage even in the event of breakage can be realized.
[0034]
In addition, the rear part of the rotor has a direct support structure that does not involve a resin part between the partition and the rotating shaft, and the rotor front part is a simple radial / thrust rolling bearing consisting of a lid, a rotating shaft, and a ball. Can be realized.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
2. The shut-off valve according to claim 1, wherein the stator is provided with a two-stage bottom-shaped metal partition disposed coaxially inside the stator to maintain airtightness and having a central bottom portion narrowed to a diameter slightly larger than the rotation shaft. And a rotor disposed coaxially with the stator inside the partition, a rotating shaft provided on the rotor by performing a surface treatment for reducing contact resistance with the partition, and a coaxially disposed at an open end of the partition. A metal lid having a hole through which the rotating shaft can pass through, and a metal lid disposed between the rotor and the rotor coaxially with the lid to support the axial center of the rotor and to extend in the axial direction of the lid and the rotor. It is composed of a radial / thrust shared rolling bearing that supports a load, a linear motion mechanism disposed on the rotary shaft protruding from the hole of the lid toward the flow path, and a valve mechanism disposed on the linear motion mechanism. As a result, the front of the rotor has a metal lid and radial The roller shaft center is supported by a shared rolling bearing, and the rotating shaft that has been subjected to a surface treatment to reduce contact resistance is directly supported by a partition at the rear of the rotor, so that the linear expansion coefficient is almost equal to that of a metallic rotating shaft. Therefore, the possibility of locking due to a temperature change is low, the minimum radial clearance can be set, the axial accuracy of the rotor at the partition open end side is increased, and stable operation performance with low power can be realized.
[0036]
And since there is no through hole in the partition and the inside and outside of the partition can be sealed with one seal member, high airtight reliability with few failure sites can be realized.
[0037]
The shut-off valve according to claim 2 comprises a stator and a rotary shaft having a two-stage bottom shape coaxially disposed inside the stator for airtight maintenance and having a central bottom portion narrowed to a diameter slightly larger than the rotary shaft. A metal partition wall that has been subjected to a surface treatment for reducing contact resistance, a rotor disposed coaxially with the stator inside the partition wall, the rotation shaft provided on the rotor, and a coaxial pole disposed on an open end of the partition wall. A metal lid having a hole through which the rotating shaft can pass, and a metal lid disposed between the rotor and the rotor coaxially with the lid to support an axis of the rotor and to form a shaft between the lid and the rotor. A radial / thrust shared rolling bearing that supports a directional load, a linear motion mechanism disposed on the rotary shaft protruding from the hole of the lid toward the flow path, and a valve mechanism disposed on the linear motion mechanism. Use pre-coated material for metal partition Door becomes possible, it is possible to realize a higher economic efficiency.
[0038]
In the shut-off valve according to the third aspect, since the surface treatment of the rotating shaft or the partition wall is performed by dispersing polytetrafluoroethylene particles in a metal material of electroless nickel plating, the surface treatment film thickness control is performed with high accuracy. As a result, it is possible to realize stable operation performance with low power and high axial center accuracy capable of suppressing radial clearance.
[0039]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0040]
(Example 1)
FIG. 1 is a sectional view of a shut-off valve according to a first embodiment of the present invention in an open state.
[0041]
In FIG. 1, an exciting coil 61 in which a conductor is wound around a substantially bobbin-shaped coil bobbin, a first electromagnetic yoke 62 having a cylindrical portion on the outer periphery and a comb-shaped magnetic pole on the inner periphery, and this electromagnetic yoke A set of two sets of a second electromagnetic yoke 63 having a generally disk-shaped and a comb-shaped magnetic pole on the inner periphery, which is disposed so as to sandwich the excitation coil 61 between the second electromagnetic yoke 63 and the second electromagnetic yoke 63, The electromagnetic yoke 63 is disposed with the disk portions facing each other. Then, the fixing means 64 made of synthetic resin is integrally filled in the entire gap between the first electromagnetic yoke 62 and the comb-shaped magnetic poles of the second electromagnetic yoke 63, and at the same time, the fixing means 64 The gap between the inside of the outer cylindrical portion of the first electromagnetic yoke 62 facing the outer periphery of the conductive wire is filled to form the stator 65.
[0042]
Inside the stator 65, a cylindrical portion 66a is formed along the magnetic pole, a closed bottom portion 66b is formed at one end, and an inner pot portion 66c is formed at the center of the bottom portion 66b with a diameter slightly larger than the rotation shaft 69. In other words, a partition 66 made of an austenitic stainless steel sheet drawn in a pot shape without a through hole having two coaxial stages is provided.
[0043]
Non-magnetic stainless steel plate, copper alloy, aluminum alloy, and the like can be selected as the material of the partition wall 66. The fuel gas, which is a low molecular hydrocarbon, and the water, hydrogen sulfide, In addition to corrosion resistance that can maintain stable performance without being deteriorated even when exposed to the above-mentioned severe temperature change in an organic environment such as active gas which is a purified impurity such as sulfur, it can be formed by progressive press working, and high economical From the viewpoint of thin-wall workability, which can achieve heat resistance, it is best to draw austenitic stainless steel sheet, and prioritize airtight reliability, apply solution heat treatment after drawing, and remove residual internal stress and It is desirable to remove crystal grains from refinement.
[0044]
A permanent magnet 67 whose outer periphery is polarized and magnetized, and a lead screw 68 formed at one end through the permanent magnet 67 to form a molybdenum disulfide coat, a fluorine coat, and preferably electroless nickel plating A metal rotating shaft 69 that has been subjected to a surface treatment such as reducing contact resistance by dispersing polytetrafluoroethylene particles in a metal matrix, and a permanent magnet 67 and a holding member 70 that holds the rotating shaft 69. A permanent magnet 67 is disposed inside the partition wall 66 so that the outer peripheral portion of the permanent magnet 67 and the magnetic poles of the electromagnetic yokes 62 and 63 of the stator 65 face each other.
[0045]
Since the inside of the partition 66 is on the gas side, the material constituting the rotor 71 is required to have high corrosion resistance. For this reason, the permanent magnet 67 is desirably a ferrite sintered magnet having high corrosion resistance to moisture, and the rotating shaft 69 can be selected from nickel or chromium-plated brass or stainless steel. Considering the possibility of containing a trace amount of a reactive gas, a stainless steel rod is particularly desirable, and the holding member 70 is made of a crystalline synthetic resin such as polybutylene terephthalate (PBT) having higher oil resistance than resistance to hydrocarbon compounds in the gas. Is desirable.
[0046]
The open end 66d of the partition 66 has an outer diameter substantially the same as that of the open end 66d, and has, at the center, a hole 72a through which the rotating shaft 69 can pass, and a concave portion 72b coaxial with the hole 72a and moving away from the inside of the partition 66. A lid 72 made of a drawn stainless steel plate is disposed by being press-fitted into the open end 66d by enclosing the rotor inside the partition wall 66, projecting the lead screw 68 from the hole 72a.
[0047]
Since the lid 72 is also on the gas side, corrosion resistance is required, and nickel or chromium-plated brass or stainless steel can be selected. However, there is a possibility that a trace amount of corrosive gas such as hydrogen sulfide is contained in the gas. In consideration of this, it is particularly preferable that it is made of stainless steel. At the same time, by forming by drawing, it can be formed by a method of high productivity such as progressive press working, and high economic efficiency can be realized.
[0048]
The lid 72 does not necessarily need to be made of a non-magnetic material, and even if a fine crack is generated due to stress corrosion, gas leakage does not occur. Therefore, solution heat treatment is not essential, and a ferrite stainless steel sheet or the like is not required. Austenitic stainless steel sheet that is not heat-treated can be selected.
[0049]
Further, the press-fitting interference with the partition 66 needs to be a loose interference so as not to apply excessive stress to the partition 66.
[0050]
A groove 69b having a smaller diameter than the other is formed between the holding member 70 of the rotating shaft 69 and the lead screw 68 and at a portion facing the recess 72b of the lid 72, and a plurality of grooves 69b are formed between the groove 69b and the recess 72b. A metal ball 75 is rotatably mounted to form a rolling bearing 76 for both radial and thrust.
[0051]
This type of shut-off valve is usually not operated at all and is left alone.For example, it is necessary to operate in response to a shut-off signal generated for the first time at the end of its life. Is done. Therefore, as the material of the ball 75, an austenitic stainless steel ball such as SUS304 which has corrosion resistance even without lubrication is optimal.
[0052]
Between the groove 69b of the rotating shaft 69 and the holding means 70, a cylindrical shape coaxial with the rotating shaft 69 and protruding outside in the direction of the groove 69b, and can hold the ball 75 when the rotating shaft 69 is arranged vertically. The temporary holding means 77 which does not come into contact with the ball 75 when it is inserted is formed integrally with the holding means 70.
[0053]
The rotary shaft 69 has a hole that can be protruded and sealed in the open hole of the flow channel 78, and a projection 79a is formed integrally with the center hole toward the center as shown in FIG. A stator 65 is fixed to the outside of the flow passage 78 of the flange 79 by fastening the electromagnetic yoke 62 by fastening or the like, and a seal member 80 such as an O-ring made of synthetic rubber is disposed between the flange 79 and the outer wall of the partition wall 66 open end 66d. The inside and outside of the channel 78 are hermetically sealed.
[0054]
A valve seat holding member 82 made of synthetic resin having self-lubricating properties, which is disposed by screwing a lead nut 81 formed in the center hole with a lead screw 68 at the end of the rotary shaft 69 on the flow path 78 side; A valve body 84 is composed of a valve seat 84 made of a flexible material such as synthetic rubber provided on the seat holding member 82 and, as shown in FIG. A slit 82a is formed in parallel with the projection 79a of the flange 79, and the slit 82a and the projection 79a constitute a rotation preventing means. The lead screw 68 and the lead nut 81 constitute a screw feed mechanism. The screw feed mechanism and the rotation preventing means constitute a linear motion mechanism.
[0055]
As the valve seat holding member 82 having the lead nut 81 formed thereon, a synthetic resin provided with a solid lubricant such as polyoxymethylene, polytetrafluoroethylene, carbon graphite, molybdenum disulfide, or the like can be selected.
[0056]
A spring 85 is compressed and arranged between the valve body 84 and the flange 79 so as to urge the valve body 84 toward the valve seat 86. At the same time, the urging force of the spring 85 is radial except when the valve is closed.・ Apply pressure to the thrust shared rolling bearing 76 to improve the accuracy of maintaining the shaft center.
[0057]
Next, the operation and operation of the shut-off valve according to the first embodiment will be described.
[0058]
When the gas usage state is not abnormal and the signals from various sensors do not indicate danger, there is no power supply from the control unit (not shown) of the microcomputer meter, the rotor 71 is stationary by the detent torque, The body 84 keeps the valve open state away from the valve seat 86, and gas can flow.
[0059]
At this time, the relative positional relationship of the rotor 71 with respect to the partition 66 is biased toward the valve seat 86 within the range of the thrust clearance because the spring 85 urges the valve body 84 to the valve seat 86 side. Since the thrust load is applied to the bearing 76 and the urging force of the spring 85 acts as a pressurizing force at the same time, the axial center holding accuracy of the radial / thrust shared bearing 76 is improved.
[0060]
When the gas usage is abnormal or the signals from the various sensors indicate danger, the control unit of the microcomputer meter applies a pulse-like current having a phase difference to each conductor of the exciting coil 61, Is rotated forward (in FIG. 1, clockwise rotation viewed from the valve body 84 side). The projection 79a, which is a rotation preventing mechanism, engages with the slit 82a to restrict the rotation of the valve seat holding member 82. Therefore, when the lead screw 68 rotates forward, the lead nut 81 moves to the valve seat 86 side, and integrally. The valve element 84 moves and comes into contact with the valve seat 86 formed in the flow path 78, and the extra pulse is stepped out, and the shutoff valve is closed.
[0061]
Thereafter, even when the control unit of the microcomputer meter stops the energization, the rotor 71 is stationary by the detent torque, and the valve body 84 maintains the closed state urged by the spring 85 to the valve seat 86.
[0062]
When the control unit of the microcomputer meter determines that the danger has been released and can be recovered from the signal from various sensors, or when the gas user recovers from the danger state and operates the return switch provided on the meter or remote control panel When a gas supplier sends a remote reset command by communication, a pulsed current having a phase difference is applied to each conductor of the exciting coil 61 to rotate the rotor 71 in the reverse direction (the valve body in FIG. 1). (Rotation counterclockwise as viewed from the side 84). Then, the valve body 84 is sent to the lead screw 68 and moves to the flange 79 side, separates from the valve seat 86, and the shut-off valve is opened.
[0063]
Thereafter, the valve element 84 moves to the flange 79 side until the valve seat holding member 82 contacts the lid 72, and further loses synchronism with an extra pulse, and the shutoff valve is fully opened.
[0064]
Then, even if the control unit of the microcomputer meter stops the energization, the rotor 71 stops because of the detent torque, and the shutoff valve maintains the open state.
[0065]
The relative positional relationship of the rotor 71 with respect to the partition 66 during the valve-opening return operation is biased toward the valve seat 86 within the range of the thrust clearance because the valve body 84 is urged toward the valve seat 86 by the spring 85. As a result, the shared radial / thrust bearing 76 receives a thrust load, and at the same time, the urging force of the spring 85 acts as a pressurizing force, so that the accuracy of holding the axial center of the shared radial / thrust bearing 76 is improved.
[0066]
Also, at the moment of valve opening when the valve element 84 is detached from the valve seat 86, the load due to the fluid pressure of gas or the like is added to the urging force of the spring 85 in the direction that obstructs the movement of the valve element 84 in the valve opening direction. However, since the radial / thrust shared bearing 76 receives a thrust load, it can be driven with small torque and small power.
[0067]
A shut-off valve using a PM type stepping motor of this type as a driving source is required to maintain the axial accuracy of the rotor and to ensure coaxiality with the airtight bulkhead for stable operation and low power.
[0068]
In addition, it is generally attached to a gas meter installed outdoors, and is exposed to severe temperature changes from a temperature exceeding 50 ° C. under direct sunlight in summer to a temperature of about −30 ° C. in severe winter, and The components on the passage 78 side are exposed to the above-mentioned severe temperature in an organic substance environment such as a fuel gas which is a low molecular hydrocarbon and an active gas which is a refined impurity such as water, hydrogen sulfide and sulfur dioxide contained in the gas. In addition, the air side is exposed to severe conditions such as a high-temperature and high-humidity environment close to the outdoor saturation humidity, and dew condensation in a gas meter. And among them, high airtight reliability without gas leakage during the service period of the gas meter (generally 10 years) is required.
[0069]
That is, it is necessary to achieve both the accuracy of maintaining the center of the rotor 71 and high airtight reliability.
[0070]
In the shut-off valve of FIG. 1, the rear part of the rotor 71 directly supports the rotating shaft 69 subjected to the surface treatment for reducing the contact resistance by the inner pot 66c of the metal partition 66, and the front part of the rotor 71 is the partition. A concave portion 72b formed on a metal plate lid 72 coaxially inserted into the open end of the hole 66, a small-diameter groove 69b formed on the metal rotary shaft 69, and a gap between the concave portion 72b and the groove 69b. Since the plurality of metal balls 75 provided form the radial / thrust shared bearing 76 and hold the axis of the rotor 71, the linear expansion coefficients of the rotary shaft 69 and the holding side are substantially equal, and the temperature is reduced. The possibility of locking due to changes is low, the minimum radial clearance can be set, the axial accuracy of the left and right rotors 71 in FIG. 1 can be increased, stable operation performance can be realized with low power, and the radial structure has a simple structure.・ Thrust sharing The simple structure directly supporting the rotary shaft 69 which has been subjected to surface treatment for the inner pot-like portion 66c of Rogari bearing 76 and the partition wall 66 to reduce the contact resistance can be realized more economical.
[0071]
In addition, since there is no through hole in the partition wall 66 and the inside and outside of the partition wall 66 can be sealed with one seal member 80, high airtight reliability with few failure parts can be realized.
[0072]
Furthermore, since the axial center holding of the rotor 71 is completed by assembling the partition wall 66 and the lid 72 with the intermediary of the rolling bearing 76 for radial and thrust, the fixing of the stator 65 and the flange 79 is performed with relatively low precision such as caulking. The method can be adopted, the production can be performed without reducing the material strength due to welding and the manufacturing conditions are not strict, and high airtight reliability and economic efficiency that do not lead to gas leakage even in the event of failure can be realized.
[0073]
Further, since the lid 72 is made of a drawn stainless steel sheet and the partition wall 66 is made of a drawn austenitic stainless steel sheet, the fuel gas which is a low molecular hydrocarbon, moisture contained in the gas minutely, and sulfuration are contained. It can maintain stable performance in an organic environment such as active gas, which is a purified impurity such as hydrogen and sulfur dioxide, and does not deteriorate even when exposed to severe temperature changes. Since it can be formed by a high-cost construction method, high economic efficiency can be realized.
[0074]
Furthermore, since the outer side protrudes in the direction of the groove 69b, the ball 75 can be held when the rotating shaft 69 is arranged vertically, and the temporary holding means 77 that does not come into contact with the ball 75 when the lid 72 is inserted is disposed. It can be a process and can realize high economic efficiency.
[0075]
As described above, according to the present invention, high airtight reliability that can withstand stress due to humidity, temperature, chemical substance environment, and the like in long-term use, and high rotor shaft center holding accuracy, stable operation performance with low power In addition, it is possible to provide a shut-off valve capable of simultaneously realizing high operation durability and economy with a simple structure.
[0076]
The radial / thrust shared bearing 76 is illustrated as a total ball type in which as many balls 75 as possible are inserted. However, the present invention is not limited to this, and can be configured with three or more balls. It is desirable to use
[0077]
Further, although the seal member 80 between the partition wall 66 and the flange 79 is shown to be compressed in the radial direction, it may be arranged to be compressed in the axial direction.
[0078]
Although the valve seat holding member 82 and the lead nut 81 have been described as being integrally formed, they may be separate parts. In this case, a spring for biasing repulsion may be provided between the valve seat holding member 82 and the lead nut 81. desirable.
[0079]
Although the valve seat 83 is illustrated as embracing the valve seat holding member 82, the valve seat 83 may be fitted at the center. May be fastened. Further, the linear motion mechanism is the lead screw 68 and the lead nut 81, but may be a cylindrical cam, a combination of a worm and a rack, or the like.
[0080]
【The invention's effect】
As described above, according to the present invention, the front portion of the rotor supports the axial center of the rotor with the metal lid and the radial / thrust shared rolling bearing, and the rear portion of the rotor has a surface treatment for reducing contact resistance. By directly supporting the shaft with the partition, the coefficient of linear expansion is almost equal to that of the metallic rotating shaft, the possibility of locking due to temperature change is low, the minimum radial clearance can be set, and the rotor on the open end side of the partition is open. The shaft center accuracy can be increased, and stable operation performance can be realized with low power.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an open state of a shut-off valve according to a first embodiment of the present invention. FIG. 2 is a perspective view of a flange and a valve body of the shut-off valve according to the first embodiment of the present invention. FIG. 4 is a sectional view of another conventional shut-off valve in an open state.
65 Stator 66 Partition wall 68 Lead screw (linear motion mechanism)
69 Rotary shaft 71 Rotor 72 Lid 72a Hole 76 Rolling bearing for both radial and thrust 81 Lead nut (linear motion mechanism)
84 valve body (valve mechanism)

Claims (3)

A stator, a metal partition having a two-stage bottom shape coaxially disposed inside the stator for airtight maintenance and having a central bottom portion narrowed down to a diameter slightly larger than the rotation axis, and the stator inside the partition; A rotor arranged coaxially with the rotor, a rotating shaft provided on the rotor by performing a surface treatment to reduce contact resistance with the partition, and a rotating shaft penetrating the center at the center by being arranged coaxially at an open end of the partition. A metallic lid having a possible hole, and a radial thrust disposed coaxially with the lid between the rotor and supporting an axial center of the rotor and supporting an axial load between the lid and the rotor. A shut-off valve comprising a shared rolling bearing, a linear motion mechanism disposed on the rotary shaft protruding from the hole of the lid toward the flow path, and a valve mechanism disposed on the linear motion mechanism. A surface treatment for reducing the contact resistance between the stator and the rotating shaft by forming a two-stage bottom shape in which the stator and the stator are coaxially arranged inside the stator to maintain airtightness and the center bottom is narrowed to a diameter slightly larger than the rotating shaft. A metal partition wall, a rotor disposed coaxially with the stator inside the partition wall, the rotation shaft provided on the rotor, and the rotation shaft disposed at the center coaxially at an open end of the partition wall. A metal lid having a hole through which the rotor can pass, and a radial cover disposed coaxially with the lid between the rotor and supporting an axial center of the rotor and supporting an axial load between the lid and the rotor. A shutoff valve comprising: a thrust shared rolling bearing; a linear motion mechanism disposed on the rotary shaft protruding from the hole of the lid toward the flow path; and a valve mechanism disposed on the linear motion mechanism. The shutoff valve according to claim 1 or 2, wherein the surface treatment is performed by dispersing polytetrafluoroethylene particles in a metal matrix of electroless nickel plating.

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