JP2015136230A - Coating member of rotor of magnet type motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating member of a rotor of a magnet type motor which can be put into close contact with the surface of the rotor readily, and by which a permanent magnet can be prevented from bolting out from a rotor rotating at a high speed in an effective and simple way.SOLUTION: A coating member of a rotor of a magnet type motor comprises a tube member formed from a thermoplastic resin including a polymer having a repeating unit expressed by the following general formula (A): -(Ar-C(=O)-Ar-O-Ar-O)-(A). [In the general formula (A), the group Ar, the group Arand the group Arindependently represent an aromatic hydrocarbon group which may have a substituent group]. The coating member has the characteristics (1) and (2) described below. (1) The shrinkage ratio of the circumference of the tube after heating at 150°C for 30 minutes is 10% or larger. (2) The tensile elasticity of the tube in TD direction after heating at 170°C for one hour subsequently to the 30-minute 150°C heating is 3,000 MPa or larger.

Description

  The present invention relates to a rotor covering member of a magnet type motor, a method for manufacturing the same, a rotor covered with a scattering prevention cover formed by the covering member, and a magnet type motor including the rotor.

  Conventionally, magnet-type motors such as brushless motors have been widely used as power for precision instruments. The magnet type motor includes a rotor in which a permanent magnet is fixed on the surface of a rotor core, and a stator that interacts with the rotor and generates a rotational moment. In the magnet type motor, since the rotor rotates at a high speed, a very strong centrifugal force is applied to the permanent magnet fixed to the surface of the rotor core with an adhesive or the like. Further, the heat generated by the magnet type motor accompanying the high-speed rotation of the rotor is also applied to the permanent magnet, and the adhesiveness is likely to be lowered. For this reason, the permanent magnet fixed to the rotor core may be scattered.

  Conventionally, in a magnet type motor, in order to prevent the permanent magnet fixed to the rotor core from scattering from the rotor core, a scattering prevention cover is attached to the surface of the rotor. This scattering prevention cover is generally made of a nonmagnetic metal cylinder such as stainless steel or aluminum. However, when a scattering prevention cover formed of metal or the like is used, there is a slight gap between the scattering prevention cover and the rotor. For this reason, there is a problem that the anti-scattering cover is likely to be eccentric and the rotor and the anti-scattering cover are likely to contact each other during high-speed rotation of the rotor. If the permanent magnet comes into contact with the anti-scattering cover during high-speed rotation of the rotor, the permanent magnet may break.

  As a device for eliminating the gap between the rotor and the anti-scattering cover, for example, in Patent Document 1, a cylindrical anti-scattering cover formed of aluminum or the like is partially contracted at equal intervals using a diameter reducing tool. After the rotor is inserted into the anti-scattering cover so that the permanent magnet is positioned between the diameter reducing tools, the diameter reducing tool is removed from the anti-scattering cover, and the anti-scattering cover is in close contact with the rotor magnet. Proposed. Patent Document 2 proposes a method in which a metal part such as stainless steel is used as a scattering prevention cover and an elastic seal member such as silicone resin is provided in the gap.

JP 2004-343817 A JP 2010-246238 A

  As described above, in the scattering prevention cover formed of metal, it is difficult to bring the scattering prevention cover and the rotor into close contact with each other, and a slight gap is generated between the scattering prevention cover and the rotor. Therefore, a method for filling such a gap has been proposed as in Patent Document 1, Patent Document 2, and the like. However, the conventional method requires a step for filling the gap, and there is a problem that it is not possible to effectively and simply prevent the permanent magnets fixed to the rotor core from being scattered by the scattering prevention cover.

  The present invention eliminates these disadvantages of the prior art. That is, the present invention provides a magnet-type motor rotor coating that can be easily adhered to the surface of the rotor and can effectively and easily prevent the permanent magnets from scattering from the rotor rotating at high speed. The main purpose is to provide a member.

The present inventor has intensively studied to solve the above-described problems of the prior art. As a result, it is a tube-shaped member formed of a thermoplastic resin containing a polymer having a repeating unit represented by the following general formula (A), and has the following characteristics (1) and (2): It has been found that the covering member of the rotor of the motor can be easily brought into close contact with the surface of the rotor, and the permanent magnets can be effectively and easily prevented from scattering from the rotor rotating at high speed.
^{- (Ar 1 -C (= O} ) -Ar 2 -O-Ar 3 -O) - (A)
[In General Formula (A), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
(1) The shrinkage ratio of the circumference of the tube after heating at 150 ° C. for 30 minutes is 10% or more. (2) After heating at 150 ° C. for 30 minutes and further at 170 ° C. for 1 hour, The tensile elastic modulus in the TD direction is 3000 MPa or more.

That is, this invention provides the invention of the aspect hung up below.
Item 1. The following general formula (A):
^{- (Ar 1 -C (= O} ) -Ar 2 -O-Ar 3 -O) - (A)
[In General Formula (A), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
A tubular member for a rotor of a magnet-type motor, which is a tube-shaped member formed of a thermoplastic resin containing a polymer having a repeating unit represented by the following (1) and (2).
(1) The shrinkage ratio of the circumference of the tube after heating at 150 ° C. for 30 minutes is 10% or more. (2) After heating at 150 ° C. for 30 minutes and further at 170 ° C. for 1 hour, Item 2. The tensile modulus in the TD direction is 3000 MPa or more. The covering member of the rotor of the magnet type motor according to Item 1, wherein the tube is a cylindrical endless tube.
Item 3. Item 3. The magnet-type motor rotor covering member according to Item 1 or 2, wherein the tube has a wall thickness of 80 µm to 500 µm.
Item 4. The following general formula (A):
^{- (Ar 1 -C (= O} ) -Ar 2 -O-Ar 3 -O) - (A)
[In the general formula (1), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
A molding step of subjecting a thermoplastic resin containing a polymer having a repeating unit represented by the following to continuous melt extrusion molding into a tube shape;
A stretching step of stretching the unstretched tube molded in the molding step;
A shrinking step of heating the drawing tube in a state where a rotor is disposed in the drawing tube obtained in the drawing step, shrinking the drawing tube, and bringing the drawing tube into close contact with the surface of the rotor;
An annealing step of annealing the coated tube by heating the coated tube coated with the rotor at a temperature higher than the heating temperature in the shrinking step;
A method for manufacturing a rotor of a magnet type motor.

  According to the covering member for the rotor of the magnet type motor of the present invention, the permanent magnet can be easily brought into close contact with the surface of the rotor, and the permanent magnet can be effectively and easily prevented from scattering from the rotor rotating at high speed. Can do. Specifically, the covering member of the present invention can be used as an anti-scattering cover adhered to the rotor by covering the surface of the rotor and shrinking and annealing the covering member. The anti-scattering cover has high mechanical strength, excellent heat resistance, and is in close contact with the surface of the rotor, so that the permanent magnets are scattered from the rotor even at high temperature and centrifugal force of the rotor rotating at high speed. Can be effectively and simply prevented. Further, the rotor covered with such a scattering prevention cover can be suitably used as a rotor of a magnet type motor. Furthermore, the magnet-type motor including the rotor covered with the anti-scatter cover can effectively exhibit stable driving because the permanent magnets are effectively prevented from being scattered from the rotor.

It is a schematic perspective view of the covering member of the rotor of the magnet type motor of the present invention. It is a schematic diagram for demonstrating the shrinkage | contraction process of this invention. It is schematic-drawing sectional drawing for demonstrating the magnet type motor produced in the Example and the comparative example.

The covering member of the rotor of the magnet type motor of the present invention is a tube-shaped member formed of a thermoplastic resin containing a polymer having a repeating unit represented by the following general formula (A). And (2) characteristics.
^{- (Ar 1 -C (= O} ) -Ar 2 -O-Ar 3 -O) - (A)
[In General Formula (A), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
(1) The shrinkage ratio of the circumference of the tube after heating at 150 ° C. for 30 minutes is 10% or more. (2) After heating at 150 ° C. for 30 minutes and further at 170 ° C. for 1 hour, The tensile elastic modulus in the TD direction is 3000 MPa or more. Hereinafter, the rotor-coated member of the magnet type motor of the present invention, the manufacturing method thereof, the rotor covered with the anti-scatter cover formed by the cover member, and the rotation A magnet type motor having a child will be described in detail.

1. Magnet Type Motor Rotor Covering Member A magnet type motor rotor covering member of the present invention is a tube-shaped member formed of a thermoplastic resin containing a polymer having a repeating unit represented by the following general formula (A). It is a member.
^{- (Ar 1 -C (= O} ) -Ar 2 -O-Ar 3 -O) - (A)

In the general formula (A), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. The group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently preferably a phenylene group that may have a substituent.

When the group Ar ¹ , the group Ar ² , and the group Ar ³ have a substituent, the substituent is not particularly limited, but the scattering prevention cover formed by the covering member is brought into close contact with the surface of the rotor, and From the viewpoint of increasing the heat resistance and mechanical strength of the anti-scattering cover and more effectively and simply preventing the scattering of the permanent magnet from the rotor rotating at high speed, preferably an alkyl group having 1 to 10 carbon atoms, carbon Examples include an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom. From the same viewpoint, each of the group Ar ¹ , the group Ar ² , and the group Ar ³ preferably has no substituent, and more preferably a phenylene group.

In the general formula (A), a polymer in which the group Ar ¹ , the group Ar ² , and the group Ar ³ are all phenylene groups is referred to as polyetheretherketone (hereinafter sometimes referred to as “PEEK”). It is a polymer. PEEK is usually produced by combining hydroquinone and benzophenone bonded to both ends using halogen as a substituent by a known nucleophilic substitution reaction. For example, it can be produced by a method of reacting 4,4′-difluorobenzophenone and hydroquinone in diphenylsulfone (DPS) in the presence of an alkali metal carbonate such as potassium carbonate and / or sodium carbonate. There is also a production method in which benzophenone and a benzene ring having a ketone group bonded with chlorine as an electrophile at both ends are bonded by a known electrophilic substitution reaction using aluminum chloride or the like as a catalyst. By adjusting the composition ratio of the monomers constituting PEEK, those having a polymer terminal as a halogen atom such as a fluorine atom can be used, and those having a hydroxyl group can also be used. Moreover, the thing by which the terminal blocker was made to react with the terminal of PEEK, and the halogen terminal and the hydroxyl group terminal were substituted by inert substituents, such as a phenyl group, can also be used.

  As a typical commercial product of PEEK, a trade name “Victrex PEEK” series manufactured by Victorx is listed. Specifically, there are Victorex PEEK450G, 381G, 151G, 90G (trade name) and the like. In addition, as a commercial product of PEEK, VESTAKEEEP (trade name) of Daicel Degussa Co., Ltd. can be mentioned, and in addition, it is marketed by Solvay.

  In the present invention, the polymer having the repeating unit represented by the general formula (A) may be a homopolymer composed of the above repeating unit, or may be a copolymer with another repeating unit. Good. In the case of a copolymer with other repeating units, from the viewpoint of closely adhering the scattering prevention cover formed by the covering member to the surface of the rotor, and increasing the heat resistance and mechanical strength of the scattering prevention cover, Specific examples of other repeating units include the following general formulas (B) to (F).

-(Ar-C (= O) -Ar-O-Ar-X-Ar-O)-(B)
-(Ar-C (= O) -Ar-O)-(C)
-(Ar-C (= O) -Ar-C (= O) -Ar-O-Ar-X-Ar-O)-(D)
_{- (Ar-SO 2 -Ar-} O-Ar-O) - (E)
_{- (Ar-SO 2 -Ar-} O-Ar-X-Ar-O) - (F)

In the general formulas (B) to (F), the plurality of groups Ar are each independently the same as the groups Ar ^{1 to} Ar ^{3 of} the above general formula (A). Examples of the group X include a single bond, an oxygen atom, a sulfur atom, a group —SO ₂ —, a group —CO—, or a divalent hydrocarbon group.

  The thermoplastic resin forming the covering member of the present invention may further contain another polymer in addition to the above polymer. Other polymers include polyetherimide (PEI), polyamideimide (PAI), polyetherketone (PEK), polyphenylsulfone (PPSU) and the like. These other polymers can be used for the purpose of reinforcing the above polymers, for example.

  In the thermoplastic resin forming the covering member of the present invention, the proportion of the polymer having the repeating unit represented by the general formula (A) is preferably about 50 to 100% by mass, more preferably 80 to 100% by mass. Degree. Moreover, as a ratio of said other polymer, Preferably about 0-20 mass% is mentioned. When the ratio of the polymer to the other polymer in the thermoplastic resin is within such a range, the scattering prevention cover formed by the covering member is brought into close contact with the surface of the rotor, and the heat resistance of the scattering prevention cover. In addition, the mechanical strength can be further increased.

  The covering member of the present invention may contain a filler and an additive as necessary in addition to the thermoplastic resin. The filler is added as necessary for the purpose of increasing the mechanical strength of the scattering prevention member formed by the covering member of the present invention. As a filler, a well-known filler can be used and inorganic fillers, such as plate shape, flake shape, and scale shape, carbon black, etc. can be used.

  Examples of inorganic fillers include scale-like or flake-like mica, mica, sericite, illite, talc, kaolinite, montmorillonite, smectite, vermiculite, plate-like or flaky titanium dioxide, potassium titanate and lithium titanate. Scaly titanate compounds, boehmite and the like. Among these, preferable examples of the filler include mica, sericite, illite, talc, kaolinite, montmorillonite, flaky titanate compound, boehmite and the like. Examples of carbon black include gas black, acetylene black, oil furnace black, thermal black, channel black, ketjen black, and carbon nanotube. A filler may be used individually by 1 type and may be used in combination of 2 or more types. When the coating | coated member of this invention contains a filler, As content of a filler, Preferably about 3-30 mass% is mentioned.

  Additives include antioxidants, thermal stabilizers, thermal conductors, plasticizers, light stabilizers, lubricants, antifogging agents, antiblocking agents, slip agents, crosslinking agents, crosslinking aids, adhesives, flame retardants, A dispersing agent etc. are mentioned. For example, it is preferable to add metal nitride (boron nitride, aluminum nitride, etc.), silicon, tin or the like as the heat conducting agent in terms of assisting the heat dissipation effect of the motor. An additive may be used individually by 1 type and may be used in combination of 2 or more types. When the covering member of the present invention contains an additive, the content of the additive is preferably about 30 to 60% by mass.

  The shape of the covering member of the present invention is a tube shape. The tube is preferably a cylindrical endless tube from the viewpoint of bringing the anti-scattering cover formed of the covering member into close contact with the surface of the rotor and increasing the heat resistance and mechanical strength of the anti-scattering cover.

  The tube thickness M (see FIG. 1) may be set as appropriate according to the size of the rotor, and is not particularly limited. However, while suppressing the increase in the space occupied by the anti-scattering cover in the magnet type motor. From the standpoint of bringing the anti-scattering cover into close contact with the surface of the rotor and increasing the heat resistance and mechanical strength of the anti-scattering cover, it is preferably about 80 to 500 μm, more preferably about 100 to 200 μm.

  Further, the length L of the tube (see FIG. 1) may be set as appropriate according to the size of the rotor, and is not particularly limited, but may be about 10 to 100 mm, for example. The outer diameter N of the tube (see FIG. 1) may be set as appropriate according to the size of the rotor and is not particularly limited, and may be about 5 to 100 mm, for example.

The covering member of the present invention has the following characteristics (1) and (2).
(1) The shrinkage ratio of the circumference of the tube after heating at 150 ° C. for 30 minutes is 10% or more.
(2) After heating at 150 ° C. for 30 minutes and further heating at 170 ° C. for 1 hour, the tensile modulus of elasticity in the TD direction of the tube is 3000 MPa or more.

Regarding the characteristic (1), the shrinkage rate of the covering member of the present invention is a value obtained by measurement as follows. For the tube after shrinkage by heating for 30 minutes in a thermostat in an atmospheric environment at 150 ° C. and the tube before shrinkage, the tube is cut in the longitudinal direction and the tube is opened. Measure with a vernier caliper and use the following formula.
Shrinkage rate = (perimeter before contraction-perimeter after contraction) ÷ perimeter before contraction x 100 (%)

  The shrinkage rate in the covering member of the present invention is preferably about 10 to 60%, more preferably about 20 to 40%. When the shrinkage rate is in such a range, the heat resistance and mechanical strength of the anti-scattering cover can be increased while further improving the adhesion of the anti-scattering cover formed by the covering member to the rotor.

  In addition, regarding the characteristic (2), the coated member of the present invention has a tensile elasticity in the TD direction of the tube after heating in a constant temperature layer at 150 ° C. for 30 minutes and further heating in an atmospheric environment at 170 ° C. for 1 hour. The rate is 3000 MPa or more. The said tensile elasticity modulus is the value obtained by measuring as follows. After heating for 30 minutes in a constant temperature bath at 150 ° C. in an atmospheric environment, a tube heated for one hour in a constant temperature bath at 170 ° C. is used as a test piece in accordance with JIS K 7127, and the tensile speed is 10 mm under a normal temperature environment. The tensile elastic modulus in the TD direction of the tube is measured under the conditions of / min.

  As the said tensile elasticity modulus in the coating | coated member of this invention, More preferably, about 3000-7000 MPa is mentioned. When the tensile modulus is in such a range, the heat resistance and mechanical strength of the anti-scatter cover can be improved while improving the adhesion of the anti-scatter cover formed by the covering member to the rotor. it can. As will be described later, in order to provide the above-described shrinkage rate in the covering member of the present invention and to provide the above tensile elastic modulus after shrinking, the covering member of the present invention is contracted under specific conditions. Further, it is necessary to perform annealing treatment under specific conditions.

  As described above, according to the covering member of the present invention, it can be easily brought into close contact with the surface of the rotor, and the permanent magnets can be effectively and easily prevented from scattering from the rotor rotating at high speed. Specifically, the covering member of the present invention can be used as an anti-scattering cover adhered to the rotor by covering the surface of the rotor and shrinking and annealing the covering member. The anti-scattering cover has high mechanical strength, excellent heat resistance, and is in close contact with the surface of the rotor, so that the permanent magnets are scattered from the rotor even at high temperature and centrifugal force of the rotor rotating at high speed. Can be effectively and simply prevented.

2. Manufacturing method of coating | coated member The coating | coated member of this invention can be manufactured by the manufacturing method provided with the following formation processes and extending processes, for example.

(Molding process)
The following general formula (A):
^{- (Ar 1 -C (= O} ) -Ar 2 -O-Ar 3 -O) - (A)
[In the general formula (1), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
A thermoplastic resin containing a polymer having a repeating unit represented by the following formula is subjected to continuous melt extrusion to form a tube.

  In the molding step, the composition of the thermoplastic resin used for continuous melt extrusion molding is as described above for the covering member. Specifically, a thermoplastic resin having the above composition and raw materials such as fillers and additives added as necessary are mixed and formed into a tube by continuous melt extrusion. As a raw material mixing method, a known mixing means can be applied, and for example, biaxial extrusion molding can be used. For continuous melt extrusion, known melt extrusion means can be applied, and examples thereof include a method using a single screw extruder and a circular mandrel die for extrusion. At this time, the thickness of the obtained tube can be adjusted to a desired thickness by appropriately setting the lip width of the circular mandrel and the extrusion molding conditions. In order to accurately maintain the shape of the tube after discharge, a mandrel such as an air ring may be used at the die outlet. In addition, by installing a circular mandrel die at the tip of the twin screw extruder, mixing of raw materials and melt extrusion can be performed at once to form a tube.

  The heating temperature in the continuous melt extrusion molding may be appropriately set according to the composition of the thermoplastic resin used as a raw material, but in terms of imparting the predetermined shrinkage rate to the covering member in the shrinking step described later, In order to make it compatible with the viewpoint which improves the heat resistance and mechanical strength after coating, Preferably it is about 350-420 degreeC, More preferably, about 370-400 degreeC is mentioned.

(Stretching process)
In the stretching process, the tube (unstretched tube) molded in the molding process is stretched. This stretching step imparts excellent heat shrinkability to the tube. This stretching process may be performed continuously with the molding process or may be performed in a separate process. The tube stretching step can be performed by tubular stretching using a known stretching apparatus. The tubular stretching may be simultaneous biaxial stretching or uniaxial stretching only in the TD direction.

  In the stretching step, stretching conditions are set in order to give the predetermined shrinkage rate to the tube constituting the covering member of the present invention. Specifically, the shrinkage rate in the TD direction is controlled by the ratio of the outer diameter of the unstretched tube to the outer diameter of the stretched tube (lateral stretching ratio). In order to obtain a covering member having the above shrinkage rate, the transverse stretching ratio is set to 1.10 or more. Further, the shrinkage rate in the MD direction is controlled by the ratio of the speed of the unstretched tube introduced into the stretched portion and the speed of the stretched tube detaching from the stretched portion (longitudinal stretch ratio). On the other hand, in order to obtain a covering member having the above-described shrinkage rate, the longitudinal stretching ratio may be arbitrary. For this reason, only the stretching in the transverse direction may be performed in a somewhat free state without fixing the length in the longitudinal direction. Moreover, you may set the longitudinal direction draw ratio in the range of about 0.95-1.20 times depending on a use application.

  The temperature under the atmosphere in which the stretching step is performed is preferably set within a range from a temperature at which the elastic modulus of the thermoplastic resin as a raw material is rapidly reduced to a crystallization temperature of the resin. Since the polymer having the repeating unit represented by the general formula (1) is a crystalline resin, crystallization progresses as the stretching temperature increases. As the crystallization progresses, the mechanical strength of the tube can be increased, but the shrinkage rate of the tube becomes smaller. Therefore, in order to achieve both the viewpoint of imparting the predetermined shrinkage ratio to the covering member and the viewpoint of increasing the heat resistance and mechanical strength after the rotor is coated, the temperature under the atmosphere in which the stretching process is performed is as follows. The temperature is preferably about 120 to 160 ° C, more preferably about 130 to 150 ° C. By selecting a temperature not higher than the crystallization temperature of the thermoplastic resin so that the crystallization does not proceed so much, the covering member can be contracted by 10% or more and easily adhered to the surface of the rotor.

  The covering member of the present invention is obtained as a long tube through the molding step and the stretching step. Therefore, it can cut | disconnect to desired length according to the magnitude | size of the rotor which coat | covers the coating member of this invention, and can be set as the coating member of this invention.

3. Rotor of magnet type motor The rotor of the magnet type motor of the present invention is a scattering prevention cover formed by heating and shrinking the above-mentioned covering member of the present invention at 130 to 160 ° C. and then annealing at 160 to 200 ° C. The surface is coated with. In the present invention, the rotor covered with the anti-scattering cover is a known rotor in which a permanent magnet is fixed to the surface of the rotor core, and rotates at high speed by interaction with a stator described later. Generates power from the motor. The method of covering and closely adhering the above-mentioned scattering prevention cover to the rotor of the magnet type motor of the present invention can be performed by applying the following shrinkage step (coating step) and annealing step to the covering member of the present invention.

(Shrinking process)
In the shrinking step, the drawing tube is heated in a state where the rotor is disposed in the drawing tube (the covering member of the present invention) obtained in the drawing step, and the drawing tube is shrunk so that the surface of the rotor is formed. Adhere the stretch tube. That is, since the rotor is covered by the covering member of the present invention by this shrinking step, the shrinking step of the covering member becomes the rotor covering step. Since the permanent magnet is fixed on the surface of the rotor, the permanent magnet is covered with the covering member of the present invention.

  A schematic diagram for explaining the shrinking process of the present invention is shown in FIG. In the contraction step, as shown in FIG. 2, the rotor 2 is disposed in the covering member 1, and in this state, the covering member 1 is heated and contracted inward to bring the covering member 1 into close contact with the rotor 2. Thus, the surface of the rotor 2 is covered with the contracted covering member 1. At this time, the contracted covering member 1 covers the permanent magnet fixed to the surface of the rotor core.

  The heating temperature in the shrinking step is preferably about 130 to 160 ° C. from the viewpoint of bringing the covering member into close contact with the surface of the rotor and increasing the heat resistance and mechanical strength of the anti-scatter cover that has undergone the annealing step described below. More preferably, about 140-150 degreeC is mentioned. The heating time is appropriately set according to the size of the rotor and the covering member. For example, the heating time is 10 minutes or more after the covering member reaches the above temperature, preferably about 10 to 15 minutes. What is necessary is just to hold | maintain temperature.

  The covering of the rotor with the covering member can be performed by, for example, covering the outer peripheral surface of the rotor with the above covering member and heating it in a thermostatic bath in a state where it is allowed to stand on a concentric shaft in a free state. .

  As described above, the covering member of the present invention can be covered with and adhered to the rotor. For example, when using an adhesive with a relatively high curing temperature, such as epoxy or silicone, as the adhesive that fixes the permanent magnet to the rotor, the extension tube shrinks by heating in the shrinking process and the permanent magnet is fixed. Curing of the adhesive to be performed can be performed in parallel. By performing these in parallel, the man-hours for manufacturing the magnet type motor can be reduced.

(Annealing process)
In the annealing step, the coated tube coated with the rotor is heated at a temperature higher than the heating temperature in the shrinking step to anneal the coated tube. The annealing process is performed to increase the mechanical strength of the coated tube coated with the rotor. That is, the annealing process increases the mechanical strength of the coated tube made of the thermoplastic resin containing the above polymer, and can more effectively prevent the permanent magnets from scattering from the rotor rotating at high speed. It becomes.

  In the shrinkage step, the tube is heated at a temperature lower than the heating temperature in the annealing step, and the crystallization of the thermoplastic resin is suppressed, so that the shrinkage rate necessary for bringing the tube into close contact with the surface of the rotor is obtained. So that it is controlled. In order to coat the rotor with the tube, it is necessary to set the contraction rate of the tube as described above. On the other hand, in the coated tube after shrinkage, since the crystallization of the thermoplastic resin constituting the coated tube is suppressed, from the viewpoint of suppressing the scattering of the permanent magnet from the rotor rotating at high speed in the magnet type motor. Insufficient mechanical strength.

  In the present invention, by performing the annealing step at a temperature higher than the heating temperature in the shrinking step, it is possible to effectively and easily suppress the scattering of the permanent magnet from the rotor that rotates at a high speed in the magnet type motor. Become. Specifically, for example, after the tube is shrunk by heating at a temperature of 150 ° C. for 30 minutes in the shrinking step, the tensile modulus in the TD direction of the tube after further heating at a temperature of 170 ° C. for 1 hour is as follows: Since it is 3000 MPa or more, scattering of the permanent magnet is effectively suppressed.

  Conventionally, thermoplastic resins including PEEK are excellent in heat resistance and mechanical strength, but have a small shrinkage rate, so that they cannot be firmly adhered to the rotor, and are applied as a covering member for the rotor. Although it was difficult, according to the covering member of the present invention, the rotor can be easily covered by performing the above-described contraction step and annealing step, and the permanent magnets can be scattered from the rotor. It can be effectively suppressed.

  In the present invention, the heating temperature of the coated tube in the annealing step is preferably higher than the heating temperature in the stretching step and higher than the crystallization temperature of the thermoplastic resin constituting the coated tube. Specifically, the temperature is preferably about 160 to 200 ° C, more preferably about 170 to 180 ° C.

  The annealing step may be performed by continuously increasing the heating temperature after the heating in the shrinking step, or the coating tube may be cooled after the shrinking step and then the heating in the annealing step may be performed. The heating time is appropriately set according to the size of the rotor and the coated tube, for example, 30 minutes or more after the temperature of the coated tube reaches the above temperature, preferably about 60 to 90 minutes, What is necessary is just to hold | maintain said temperature.

  The annealing step can be performed, for example, by heating the rotor coated with the coated tube in a constant temperature layer.

4). Magnet type motor The magnet type motor of the present invention comprises the above-described rotor covered by the anti-scattering cover formed by the covering member of the present invention, and a stator that interacts with the rotor and generates a rotational moment. I have. As described above, the surface of the rotor of the present invention is covered with the anti-scattering cover formed by heating and shrinking the coated member of the present invention at 130 to 160 ° C. and then annealing at 160 to 200 ° C. The anti-scattering cover has high mechanical strength and heat resistance, and is in close contact with the rotor surface. For this reason, the magnet type motor of the present invention provided with the rotor covered with the anti-scattering cover can effectively and easily suppress the scattering of the permanent magnet from the rotor rotating at high speed. Therefore, stable driving can be demonstrated.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples. In the present invention, the shrinkage rate and tensile modulus of the tube were measured as follows.

<Shrinkage rate>
The shrinkage rate of the tube was determined by cutting the tube in the longitudinal direction with respect to the tube after contraction and the tube before contraction contracted in “(3) Tube contraction step” in the examples and comparative examples. And the circumference of the tube was measured with a caliper, and obtained by the following formula.
Shrinkage rate = (perimeter before contraction-perimeter after contraction) ÷ perimeter before contraction x 100 (%)

<Tensile modulus>
The tensile elastic modulus is obtained by using the tube obtained in “(4) Tube annealing step” in the examples and comparative examples as a test piece in accordance with JIS K 7127, under a normal temperature environment and a tensile speed of 10 mm / min. The tensile elastic modulus in the TD direction was measured.

<Example 1>
A tube was manufactured by the following method, and the shrinkage rate of the tube and the tensile elastic modulus of the tube after shrinkage were measured by the above method. The results are shown in Table 1.
(1) Molding process of thermoplastic resin into tube shape As a thermoplastic resin, PEEK (polyetheretherketone, PEEK450G manufactured by Victrex) was introduced into a single screw extruder with a screw diameter of 30 m, an outer diameter of 24 mm, meat Molded into a 120 μm thick tube.
(2) Tube Stretching Step The formed tube was cut to a length of 1000 mm, applied with an internal pressure of 0.2 MPa while being heated to 150 ° C., and expanded to an outer diameter of 30 mm. Next, it cooled to room temperature in the state which applied the internal pressure, and when the internal pressure was cancelled | released, the shrinkable tube with an outer diameter of 30 mm and a wall thickness of 100 micrometers was obtained.
(3) Shrinkage step of the tube The tube obtained in the stretching step was heated for 30 minutes in a thermostatic bath in an atmospheric environment at 150 ° C., the tube was shrunk, and the shrinkage rate was measured by the above method.
(4) Tube annealing step The contracted tube was heated in a constant temperature layer at 170 ° C. in an atmospheric environment for 1 hour, and the tensile elastic modulus of the obtained tube was measured by the above method.

<Example 2>
A tube was manufactured by the following method, and the shrinkage rate of the tube and the tensile elastic modulus of the tube after shrinkage were measured by the above method. The results are shown in Table 1.
(1) Molding process of thermoplastic resin into tube shape As a thermoplastic resin, PEEK (polyetheretherketone, PEEK450G manufactured by Victrex) was used, and a raw material with 15% acetylene black added thereto was used with a screw diameter of 30 m. The product was put into a single screw extruder and formed into a tube shape having an outer diameter of 24 mm and a wall thickness of 120 μm.
(2) Stretching step of the tube The tube was cut to a length of 1000 mm, applied with an internal pressure of 0.3 MPa while being heated to 150 ° C., and expanded to an outer diameter of 30 mm. Next, it cooled to room temperature in the state which applied the internal pressure, and when the internal pressure was cancelled | released, the shrinkable tube with an outer diameter of 30 mm and a wall thickness of 100 micrometers was obtained.
(3) Shrinkage step of the tube The tube obtained in the stretching step was heated for 30 minutes in a thermostatic bath in an atmospheric environment at 150 ° C., the tube was shrunk, and the shrinkage rate was measured by the above method.
(4) Tube annealing step The contracted tube was heated in a constant temperature layer at 170 ° C. in an atmospheric environment for 1 hour, and the tensile elastic modulus of the obtained tube was measured by the above method.

<Example 3>
A tube was manufactured by the following method, and the shrinkage rate of the tube and the tensile elastic modulus of the tube after shrinkage were measured by the above method. The results are shown in Table 1.
(1) Molding process of thermoplastic resin into tube shape As a thermoplastic resin, PEEK (polyetheretherketone, PEEK450G manufactured by Victrex) was used, and a raw material obtained by adding 10% of talc to this was simply a 30 m screw diameter. The product was put into a shaft extruder and formed into a tube shape having an outer diameter of 24 mm and a wall thickness of 120 μm.
(2) Stretching step of the tube The tube was cut to a length of 1000 mm, applied with an internal pressure of 0.3 MPa while being heated to 150 ° C., and expanded to an outer diameter of 30 mm. Next, it cooled to room temperature in the state which applied the internal pressure, and when the internal pressure was cancelled | released, the shrinkable tube with an outer diameter of 30 mm and a wall thickness of 100 micrometers was obtained.
(3) Shrinkage step of the tube The tube obtained in the stretching step was heated for 30 minutes in a thermostatic bath in an atmospheric environment at 150 ° C., the tube was shrunk, and the shrinkage rate was measured by the above method.
(4) Tube annealing step The contracted tube was heated in a constant temperature layer at 170 ° C. in an atmospheric environment for 1 hour, and the tensile elastic modulus of the obtained tube was measured by the above method.

<Comparative Example 1>
A tube was manufactured by the following method, and the shrinkage rate of the tube and the tensile elastic modulus of the tube after shrinkage were measured by the above method. The results are shown in Table 1.
(1) Molding process of thermoplastic resin into tube shape As a thermoplastic resin, PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer, 350J manufactured by MDF) was introduced into a single screw extruder with a screw diameter of 30 m. The tube was formed into a tube shape having an outer diameter of 24 mm and a wall thickness of 120 μm.
(2) Stretching step of the tube The tube was cut to a length of 1000 mm, applied with an internal pressure of 0.3 MPa while being heated to 150 ° C., and expanded to an outer diameter of 30 mm. Next, it cooled to room temperature in the state which applied the internal pressure, and when the internal pressure was cancelled | released, the shrinkable tube with an outer diameter of 30 mm and a wall thickness of 100 micrometers was obtained.
(3) Shrinkage step of the tube The tube obtained in the stretching step was heated for 30 minutes in a thermostatic bath in an atmospheric environment at 150 ° C., the tube was shrunk, and the shrinkage rate was measured by the above method.
(4) Tube annealing step The contracted tube was heated in a constant temperature layer at 170 ° C. in an atmospheric environment for 1 hour, and the tensile elastic modulus of the obtained tube was measured by the above method.

<Reference Example 1>
About the tube after contraction obtained in Example 1, the tensile elasticity modulus before performing an annealing process was measured by said method.

(Test example)
In Examples 1 to 3 and Comparative Example 1, a rotor 2 (in which a permanent magnet 22 is fixed to the surface of a rotor core 21 as shown in FIG. In the state where the outer diameter was 28 mm and the length was 50 mm, the above-described contraction process and annealing process were performed, and the rotor 1 was covered with the tube 1. The permanent magnet 22 is fixed with a thermosetting epoxy adhesive. In Reference Example 1, only the shrinking process was performed, and the rotor 1 was covered with the tube 1 without performing the annealing process. Next, the rotating shaft 4 was inserted into the center of the rotor 2 covered with the tube 1, mounted on a magnet type motor, and rotated at 450 rpm for 300 hours. Then, the presence or absence of the scattering of the permanent magnet 22 fixed to the rotor core 21 was confirmed. The case where the permanent magnet 22 was not scattered was evaluated as ◯, the case where the permanent magnet 22 was broken and scattered, the case where X was not scattered, but the case where a part of the tube 1 was deformed was evaluated as △. did. The results are shown in Table 1.

  As is clear from the results shown in Table 1, in the tube using PEEK as the thermoplastic resin, the shrinkage ratio of the circumference of the tube when heated at 150 ° C. in the atmosphere for 30 minutes is 10% or more, When the tensile modulus of elasticity in the TD direction of the tube after further heating at 170 ° C. in the atmosphere for 1 hour is 3000 MPa or more, the tube is used as a covering member for the rotor, so that the rotor can be a magnet type motor. Even when mounted, there was no scattering of permanent magnets. Moreover, by using the tubes of Examples 1 to 3 as the rotor covering member (scattering prevention cover), the covering member and the rotor could be easily brought into close contact with each other by contraction due to heating. Thus, according to the tubes of Examples 1 to 3, it can be easily brought into close contact with the surface of the rotor, and the permanent magnets can be effectively and easily prevented from scattering from the rotor rotating at high speed. did it.

  On the other hand, in the tube of Comparative Example 1 using PFA as a thermoplastic resin, the shrinkage rate is 10%, and the rotor can be coated with high adhesion, but the tensile elastic modulus is small, and the rotor is mounted on a magnet type motor. Permanent magnets were scattered. In addition, in the tube of Reference Example 1 in which the tube obtained by stretching in Example 1 was contracted and coated on the rotor and then the annealing process was not performed, the tensile modulus decreased, and the permanent magnets were scattered. Although there was no, part of the tube was deformed.

DESCRIPTION OF SYMBOLS 1 ... Rotor covering member 2 of a magnet type motor ... Rotor 21 ... Rotor core 22 ... Permanent magnet 3 ... Rotating shaft L ... Tube length M ... Tube thickness N ... Tube outer diameter

Claims (4)

The following general formula (A):
^{- (Ar 1 -C (= O} ) -Ar 2 -O-Ar 3 -O) - (A)
[In General Formula (A), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
A tubular member for a rotor of a magnet-type motor, which is a tube-shaped member formed of a thermoplastic resin containing a polymer having a repeating unit represented by the following (1) and (2).
(1) The shrinkage ratio of the circumference of the tube after heating at 150 ° C. for 30 minutes is 10% or more. (2) After heating at 150 ° C. for 30 minutes and further at 170 ° C. for 1 hour, The tensile elastic modulus in the TD direction is 3000 MPa or more.   The covering member of the rotor of the magnet type motor according to claim 1, wherein the tube is a cylindrical endless tube.   The covering member of the rotor of the magnet type motor according to claim 1 or 2, wherein the tube has a thickness of 80 µm to 500 µm. The following general formula (A):
^{- (Ar 1 -C (= O} ) -Ar 2 -O-Ar 3 -O) - (A)
[In the general formula (1), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
A molding step of subjecting a thermoplastic resin containing a polymer having a repeating unit represented by the following to continuous melt extrusion molding into a tube shape;
A stretching step of stretching the unstretched tube molded in the molding step;
A shrinking step of heating the drawing tube in a state where a rotor is disposed in the drawing tube obtained in the drawing step, shrinking the drawing tube, and bringing the drawing tube into close contact with the surface of the rotor;
An annealing step of annealing the coated tube by heating the coated tube coated with the rotor at a temperature higher than the heating temperature in the shrinking step;
A method for manufacturing a rotor of a magnet type motor.