JP4761016B2 - Servo motor with reduction gear made of high radiation resistant material - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a servomotor with a speed reducer in which all major components are made of a high radiation resistance material, and withstands an irradiation dose of 100 MGy (mega gray) or more under a gamma dose rate of 10 KGy / h (kilo gray per hour). It can be used under neutron irradiation including high temperatures of 100 ° C. or higher. The servo motor of the present invention can be used particularly in the following fields.
[0002]
・ Power sources for various equipment installed around the reactor, nuclear fuel reprocessing facility, and accelerator.
・ Power sources for accelerators and radiation generators.
・ Power source for in-vessel maintenance equipment of fusion reactor.
[0003]
・ Power source for robot systems for extreme environments (radiation and high temperatures).
・ Power source for medical equipment using radiation.
・ Power source for onboard equipment and devices.
[0004]
[Prior art]
A servo motor with a speed reducer consists of a motor body, an angle detector, and a speed reducer. The motor can control the rotation angle (position) and speed of the motor by an external command signal. In general, an optical rotary encoder or resolver is used, and the speed reducer is coupled to a rotating shaft of a motor to obtain a required torque, and is generally composed of a large number of gears.
[0005]
In conventional servo motors with radiation-resistant speed reducers, epoxy resin is used for the insulation material of windings and lead wires, and plastic is used for lead wire protective bushes, stator covers, caps, and resolver type angle detector bobbins. Since materials were used, the deterioration of electrical characteristics such as insulation resistance and withstand voltage and the deterioration of mechanical characteristics such as tensile strength, brittleness, and elongation were remarkable with the increase of irradiation dose by gamma rays.
[0006]
On the other hand, mineral oil or synthetic oil grease lubricants were used to lubricate bearings and gears of the reduction gears to support the rotating shaft. Deterioration of properties such as consistency (hardness), oil separation, dropping point, free acid, etc., which serve as an index of lubrication characteristics. As a result, the rotation of the servo motor with a reduction gear becomes impossible due to an increase in load torque due to hardening of grease. I made it.
[0007]
As a result of the above, the radiation resistance value of the conventional servomotor with radiation-resistant speed reducer was limited to 1 MGy.
[0008]
[Problems to be solved by the invention]
As mentioned above, since the radiation resistance value of the conventional servomotor with a radiation-resistant speed reducer is 1 MGy, around the melting tank of a nuclear reactor or nuclear fuel reprocessing facility, or in the reactor of a fusion reactor, When used in a high place where the radiation dose rate is evaluated as 10 kGy / h, it exceeds the allowable radiation resistance value in a short time (about 100 hours) and cannot be used practically. On the other hand, when a servo motor with a speed reducer as a power source is installed at a remote location with a low radiation dose rate in order to avoid use under a high radiation dose rate, a long power transmission mechanism is required. It becomes a factor which reduces reliability.
[0009]
In the present invention, the material of the main components of the servo motor with a reduction gear is made of a high radiation resistance material without damaging the basic performance possessed by the servo motor with the reduction gear, and for a long time under a radiation dose rate of 10 kGy / h. Provide a servo motor with a reduction gear that can be operated (several thousand hours or more).
[0010]
[Means for Solving the Problems]
The present invention adopts the following configuration in order to solve the above problems.
1) As an electrical insulating material for the motor winding and resolver type angle detector winding, a combination of a polyimide resin fiber and a ceramic fiber of alumina, silicon oxide, or silicon nitride is used.
[0011]
2) As an electrical insulating material for the motor lead wire and the angle detector lead wire, polyimide resin, ceramics such as alumina, silicon oxide, silicon nitride, or a combination of these fibers is used.
[0012]
3) As a lead wire protective bushing material, polyimide resin or ceramics such as alumina, silicon oxide, silicon nitride is used.
4) As a cover or cap material for the stator for the motor or resolver type angle detector, polyimide resin or ceramics such as alumina, silicon oxide, silicon nitride, or the like is used.
[0013]
5) As a resolver type angle detector bobbin material, polyimide resin or ceramics such as alumina, silicon oxide, silicon nitride or the like is used.
6) Grease with synthetic base oil and thickener inorganic bentonite as a lubricant for bearings and reduction gears. Aluminum, zinc, nickel, chromium, palladium, zeolite, Use grease lubricant mixed with fine powder of either silica or alumina.
[0014]
7) As the resin for coil molding and assembly, use is made of a resin made of a siloxane-bonded compound or a resin made inorganic after high-temperature treatment with a resin made of a siloxane-bonded compound.
[0015]
By adopting the above configuration, the radiation resistance of the servo motor with a reduction gear according to the present invention is 100 times (100 MGy) compared to the radiation resistance of 1 MGy of a conventional servo motor with a reduction gear, which makes the present invention possible. The technical items are as follows.
[0016]
1) Polyimide resin with 100 times or more radiation resistance compared to epoxy resin used for conventional windings and lead wires, or ceramic materials such as alumina, silicon oxide and silicon nitride as electrical insulation materials I used it.
[0017]
2) Lead wire bush, stator cover, cap, bobbin material for resolver type angle detectors, polyimide resin, alumina, silicon oxide with radiation resistance 1000 times to 10,000 times that of conventional plastic materials Use ceramic materials such as silicon nitride.
[0018]
3) Compared with conventional mineral oil or synthetic oil grease or solid lubricant, the lubricant for bearings and gears is a grease lubricant with a radiation resistance 10 to 100 times or more (base oil is a synthetic oil) In addition, the thickener was inorganic bentonite, and the additive was grease containing aluminum, zinc, nickel, chromium, palladium, zeolite, silica, or alumina fine powder.
[0019]
4) High-temperature treatment of wire-forming and assembly adhesives with a siloxane-bonded compound or a siloxane-bonded compound that has 10 to 100 times more radiation resistance than conventional epoxy materials The use of a resin that becomes mineralized afterwards.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an external view of a servomotor with a radiation-resistant speed reducer according to the present invention. In the external view, a motor main body 1, a resolver 2 as an angle detector, a reduction gear 3, a rotating shaft 4, a motor main body lead wire 5, the same protective bush 6, a resolver lead wire 7 and the same protective bush 8 are shown. .
[0021]
FIG. 2 is a cross-sectional view of FIG. The motor body 1 includes a stator winding 9, a rotor 10, a rotating shaft 11, and bearings 12 and 13 that support the rotating shaft. Polyimide resin was used for the electrical insulation material of the stator winding ( this example is a reference technology of the present invention, and in the present invention, it is one of polyimide resin fiber, alumina, silicon oxide and silicon nitride) Use a combination with ceramic fibers) . In the embodiment of the present invention, the rotor uses a permanent magnet made of an inorganic material. However, in the case of a winding type, an electrically insulating material similar to the stator winding can be used. A resin made of a siloxane-bonded compound was used for forming the winding. As the lubricant for the bearings 12 and 13, a grease using a base oil as a synthetic oil and a thickener as an inorganic bentonite and a grease lubricant mixed with fine aluminum powder was used. Further, polyimide resin was used for the electrical insulating material of the lead wire 5 and the protective bush 6 of the lead wire.
[0022]
The resolver 2 includes a stator winding 14 and a rotor winding 15, and the rotation axis is coaxial with the motor rotation axis. Polyimide resin was used as an electrical insulating material for these windings. A resin made of a siloxane-bonded compound was used for forming the winding. Alumina was used as the bobbin material that forms the core of the winding. Further, polyimide resin was used for the electrical insulating material of the lead wire 7 and the protective bush 8 of the lead wire.
[0023]
The reduction gear 3 employs a planetary gear system in the embodiment of the present invention. The rotation shaft of the motor is coupled to a number of gears 16 and is transmitted to the rotation shaft 4 as an output. The rotating shaft 4 is supported by two bearings 17 and 18. As the lubricant for these gears and bearings, a grease lubricant containing a synthetic oil as a base oil and inorganic bentonite as a thickener and mixed with fine aluminum powder was used.
[0024]
【Example】
The two servo motors with speed reducers were irradiated with gamma rays with a dose rate of 10 kGy / h in the air and at room temperature. During irradiation, the motor was operated continuously. FIG. 3 shows the test results. The vertical axis represents the relative value when the motor current value is 1 before irradiation, and the horizontal axis represents the irradiation amount of gamma rays. An abnormality of the motor during irradiation appears as a rapid increase or decrease in the current value. The fluctuation of the current value during the irradiation time of 100 MGy (mega gray) and 10,000 hours (about 1 year and 2 months) is very small for both motors, there is no abnormality during irradiation, and in the inspection after irradiation No abnormalities were found.
[0025]
【The invention's effect】
The effects of the invention of the servo motor with a high radiation resistance reduction gear according to the present invention are as follows.
-It can be used maintenance-free for a long period of time as a power source for various devices equipped under a high radiation environment such as nuclear reactors, nuclear fuel reprocessing facilities, accelerators, radiation generators, and medical devices using radiation.
[0026]
・ Can be used maintenance-free for a long time as a power source for in-vessel maintenance equipment of fusion reactors.
-Since there is no need to install a power source at a distance, the efficiency and reliability of the device can be improved.
[0027]
-It can be used as a power source for robot systems for extreme environments (radiation and high temperatures).
-Since high reliability can be ensured, it can be used as a power source for space-borne equipment and devices.
[Brief description of the drawings]
FIG. 1 is an external view of a servomotor with a high radiation resistance reduction gear.
[Explanation of symbols]
1. Motor body 2. Resolver type angle detector Reducer 4. Rotation shaft 5. Lead wire for motor body Bush for protecting the lead wire for the motor body 7. 7. Lead wire for angle detector Bush for protecting lead wire for angle detector [FIG. 2] A cross-sectional view of a servo motor with a high radiation resistance reduction gear.
[Explanation of symbols]
1. Motor body 2. Resolver type angle detector Reducer 4. Rotation shaft 5. Lead wire for motor body Bush for protecting the lead wire for the motor body 7. 7. Lead wire for angle detector 8. Bushing for lead wire protection for angle detector Stator winding for motor 10. 10. Motor rotor Rotating shaft 12. Bearing 13. Bearing 14. Resolver stator winding 15. Resolver rotor winding 16. Reduction gear gear 17. Bearing 18. Bearing FIG. 3 is a diagram showing a test result of a servo motor with a high radiation resistance reduction gear.

Claims (8)

A servo motor comprising a motor body having a winding, a resolver type angle detector having a winding, and a speed reducer,
As an electrical insulating material for the winding of the motor body and the winding of the angle detector, a combination of polyimide resin fiber and ceramic fiber that is one of alumina, silicon oxide and silicon nitride,
As a lubricant for the gear of the speed reducer,
Grease with base oil as synthetic oil and thickener as inorganic bentonite, mixed with fine powder of aluminum, zinc, nickel, chromium, palladium, zeolite, silica or alumina to prevent deterioration due to radiation. Servo motor that uses grease lubricant . The motor body further includes a leader line, and the angle detector further includes a leader line,
As an electrically insulating material for the lead wire of the motor body and the lead wire of the angle detector,
The servo motor according to claim 1, wherein the polyimide resin, the ceramic, or the combination is used. The motor body further includes a lead wire protection bush, and the angle detector further includes a lead wire protection bush,
As materials for the lead wire protection bush of the motor body and the lead wire protection bush of the angle detector,
The servo motor according to claim 2, wherein the polyimide resin or the ceramic is used. The motor body further includes a stator, a stator cover, and a cap, and the angle detector further includes a stator, a stator cover, and a cap,
As the material of the stator cover and cap of the motor body, and the material of the stator cover and cap of the angle detector,
The servomotor according to claim 1, wherein the polyimide resin or the ceramic is used . The angle detector further comprises a bobbin;
As the bobbin material,
The servo motor according to claim 1, wherein the polyimide resin or the ceramic is used . A bearing for supporting a rotation shaft of the motor body, the angle detector and the speed reducer;
The servo motor according to claim 1, wherein the lubricant is used for the bearing . As a resin for molding the motor body and the coil of the angle detector,
The servomotor according to any one of claims 1 to 6, wherein a resin made of a siloxane-bonded compound or a resin that becomes inorganic after high-temperature treatment with a resin made of a siloxane-bonded compound is used. The servo motor according to any one of claims 1 to 7, wherein the resolver-type angle detector is replaced with an optical rotary encoder made of a radiation-resistant material.

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