JP2012210107A - Vibration wave motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration wave motor with a stable output performance, little aging variation, and restrained noises.SOLUTION: In a vibration wave motor 1, a dynamic body 13 is brought into pressure contact with a vibrator 12 generating progressive waves on a surface via a frictional material 14, and the dynamic body 13 is moved using a frictional force generated by the progressive waves. The frictional material 14 is fixed to a face, on which the vibrator 12 and the dynamic body 13 are opposed to each other. The frictional material 14 is made into a molding obtained from a molding material containing a liquid crystal polymer and having a flow starting temperature of 350°C or more.

Description

  The present invention relates to a vibration wave motor.

  In general, a vibration wave motor has a structure in which a vibrating body fixed to a piezoelectric body and a moving body are in pressure contact with each other, and a traveling wave is generated in the piezoelectric body and the vibrating body by applying electric power to the piezoelectric body. The moving body is relatively moved by frictional force to obtain mechanical energy.

FIG. 1 is a diagram illustrating the main part of such a vibration wave motor, in which (a) is a perspective view and (b) is an enlarged cross-sectional view.
In the vibration wave motor 1 shown here, the vibrating body 12 is fixed on the piezoelectric body 11, the friction material 14 is fixed on the moving body 13, and the friction material 14 is superimposed on the vibrating body 12, The moving body 13 is pressed and contacted via the friction material 14.
When electric power is applied to the piezoelectric body 11, a traveling wave in the direction of arrow A is generated on the vibrating body 12. At this time, each mass point of the oscillating body 12 has an elliptical motion as indicated by an arrow B, and each wave front moves in the opposite direction horizontally to the traveling wave direction. It has the property of moving horizontally in the same direction as the traveling wave. Therefore, the moving body 13 disposed on the vibrating body 12 via the friction material 14 contacts only the upper part of the wave front, and moves horizontally in the direction of the arrow C by the frictional force with the vibrating body 12.

  Usually, the material of the vibrating body 12 and the moving body 13 includes metals such as iron, stainless steel, and aluminum. Since the vibration wave motor 1 has a structure in which the moving body 13 is in pressure contact with the vibrating body 12, in order to obtain a large motor output, the pressure at the time of pressurization is increased or the vibrating body 12 and the friction material 14. It is necessary to increase the friction coefficient between the two. The friction material 14 is used for this purpose and is made of rubber or engineering plastic. Thereby, the vibration wave motor 1 reduces the wear of the vibrating body 12 and the moving body 13, and can obtain mechanical energy stably for a long period of time.

  However, when the friction material 14 is made of rubber or the like and has a large friction coefficient, the friction material 14 is heavily worn, and the wear powder adheres to the contact surfaces of the vibrating body 12 and the friction material 14, and the frictional force between the two, That is, there is a problem that the brake torque varies with time. In addition, when an engineering plastic filled with asbestos fiber or inorganic powder having high wear resistance is used as the friction material 14, many scratches are generated on the surface of the vibrating body 12, and the brake torque varies with time. There was a problem that. Furthermore, the resonance frequency of the vibrating body 12 fluctuates with time due to the influence of wear powder adhering to the vibrating body 12, and there is a problem that stable startability cannot be obtained.

Thus, as means for solving these problems, it is disclosed that a liquid crystal polymer composition is used for the friction material.
For example, Patent Document 1 discloses a vibration wave motor that uses a friction material made of a liquid crystal polymer or a liquid crystal polymer composition containing a filler for adjusting frictional force. And, compared to a friction material made of glass fiber and phenol resin, when a composition containing carbon fiber, glass fiber or polytetrafluoroethylene is used as a filler, the friction material is less worn, the rotational speed and It is disclosed that deterioration with time of machine output such as torque is suppressed.

  Patent Document 2 discloses a vibration wave motor using a composite resin layer containing a filler as a base material of a liquid crystal polymer made of aromatic polyester as a friction material. And it is described that according to this vibration wave motor, it is possible to realize a large output type vibration wave motor which does not squeak during no load operation or low load operation.

  Patent Document 3 discloses that a molded article of a composite resin in which a thermoplastic resin having a glass transition point of 100 ° C. or higher is used as a matrix resin and a fibrous reinforcing material oriented in the circumferential direction is blended is used as a moving object. ing. Further, in order to suppress squeal at the time of no-load operation or low-load operation, and to eliminate the need for the rubber elastic sheet for vibration damping required conventionally between the moving body and the output shaft, the matrix The use of a liquid crystal polymer as the resin is disclosed. And it is described that according to this vibration wave motor, the waviness and nonuniformity of the torque at the time of rated operation can be reduced.

  Patent Document 4 discloses a liquid crystal polymer composition mainly composed of a thermotropic liquid crystal polymer and an inorganic filler as a material having a small variation in the wear coefficient of a sliding material (slider material) in a minute time. It is described that the use of this composition stabilizes the torque, efficiency, and rotational speed of the vibration wave motor.

JP-A-2-17872 JP-A-3-173370 JP-A-3-285574 Japanese Unexamined Patent Publication No. 6-197567

However, in the invention described in Patent Document 1, although friction material is less worn and deterioration of output such as rotation speed and starting torque at the time of no-load operation is suppressed, the effect is not sufficient, and torque is not sufficient. There was a problem that it became unstable and the rotation speed and efficiency were not stable, and squeal occurred during use.
Further, in the invention described in Patent Document 2, when graphite or polytetrafluoroethylene (PTFE) is used as a filler, there is a problem that only a medium output can be obtained because the wear resistance of the friction material is low. there were. In addition, when carbon fiber is used as the filler, although the friction material has high wear resistance, the carbon fiber is expensive, and the contact surface of the vibrating body is hardened with cemented carbide treatment and polishing. Even if it is a thing, there existed a problem that the torque nonuniformity estimated to originate in the damage | wound produced by the carbon fiber will generate | occur | produce.
Further, the invention described in Patent Document 3 also has a problem that torque undulation and unevenness cannot be sufficiently suppressed.
Further, the invention described in Patent Document 4 has a problem that the wear resistance of the sliding material is low, and the fluctuation of the efficiency and the rotational speed of the vibration wave motor is large.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vibration wave motor in which output performance is stable, changes with time are small, and occurrence of squeal is suppressed.

To solve the above problem,
The present invention is a vibration wave motor that moves a moving body using a frictional force generated by the traveling wave by pressing the moving body through a friction material on a vibrating body that generates a traveling wave on the surface. The friction material is fixed to a surface of the vibrating body or the moving body facing each other, and the friction material includes a liquid crystal polymer and has a flow start temperature of 350 ° C. or higher. A vibration wave motor is provided.
In the vibration wave motor of the present invention, the liquid crystal polymer is preferably liquid crystal polyester.
In the vibration wave motor of the present invention, it is preferable that the molding material further includes a filler.
In the vibration wave motor of the present invention, the filler preferably has a Mohs hardness of 7 or less.
In the vibration wave motor of the present invention, the filler is preferably glass fiber or glass particles.

  According to the present invention, it is possible to provide a vibration wave motor in which output performance is stable, changes with time are small, and occurrence of squeal is suppressed.

It is a figure which illustrates the principal part of a vibration wave motor, (a) is a perspective view, (b) is an expanded sectional view. 1 is a schematic perspective view illustrating an embodiment of a vibration wave motor of the present invention. It is an enlarged view which shows the principal part of the vibration wave motor shown in FIG.

Hereinafter, the present invention will be described in detail.
The vibration wave motor of the present invention is a vibration wave that moves a moving body by using a frictional force generated by the traveling wave by bringing the moving body into pressure contact with a vibrating body that generates a traveling wave on the surface through a friction material. The motor is a motor, wherein the friction material is fixed to a surface of the vibrating body or moving body facing each other, and the friction material includes a liquid crystal polymer and has a flow start temperature of 350 ° C. or higher. It is a molded product obtained. By using a friction material that is obtained from a molding material having a flow starting temperature of 350 ° C. or higher, the vibration wave motor is less susceptible to frictional heat generated during operation of the friction material, and is resistant to wear. It does not damage the surface of the vibrating body or moving body. As a result, fluctuations in the rotational speed and the starting torque are suppressed, and the occurrence of squeal is suppressed.

The vibration wave motor of the present invention can have the same configuration as that of a conventional vibration wave motor except that the above friction material is used.
FIG. 2 is a schematic perspective view illustrating one embodiment of the vibration wave motor of the present invention. In FIG. 2, a notch is partially provided in order to make the configuration of the vibration wave motor easier to see.
In the vibration wave motor 1 shown here, the vibrating body 12 is fixed on the piezoelectric body 11, the friction material 14 is fixed on the moving body 13, and the friction material 14 is superimposed on the vibrating body 12, The moving body 13 is pressed and contacted via the friction material 14. The piezoelectric body 11, the vibrating body 12, and the moving body 13 are all substantially disk-shaped and have substantially the same diameter. However, their shape and size are not limited to those shown here, and can be adjusted as appropriate.

The piezoelectric body 11 may be a known one and is not particularly limited.
The material of the vibrating body 12 and the moving body 13 is preferably a metal or an alloy such as iron, stainless steel, or aluminum, and may be the same or different.
The vibrating body 12 is fixed to the surface of the piezoelectric body 11 with an adhesive or the like.

A plurality of rectangular parallelepiped shapes are drawn on the surface 12 a of the vibrating body 12 opposite to the surface fixed to the piezoelectric body 11 (that is, the surface facing the moving body 13) along the outer periphery of the vibrating body 12. . Are provided. The plurality of protrusions 121, 121... Are radially provided with two opposite sides (here, long sides) facing the radial direction of the surface 12 a of the vibrating body 12. In addition, the plurality of protrusions 121, 121... Are notched when the position of the space between adjacent ones (the protrusions 121, 121. Is adjusted so that the vibration displacement becomes maximum when the piezoelectric body 11 is driven. The protrusion 121 is provided to make the vibration part easier to mechanically vibrate.
The height of the protrusion 121 may be appropriately adjusted according to the purpose, but is preferably 0.001 to 1 mm.

A ring-shaped friction material 14 is fixed to the surface 13 a of the moving body 13 facing the vibrating body 12 along the outer periphery of the moving body 13. The friction material 14 is preferably fixed to the moving body 13 with an adhesive or the like.
The friction material 14 is disposed in contact with the plurality of protrusions 121, 121.
The thickness of the friction material 14 may be appropriately adjusted according to the purpose, but is preferably 0.1 to 10 mm. The width of the friction material 14 is preferably set so as to cover the entire contact surface of the protrusion 121.

  The friction material 14 is a molded body obtained from a molding material containing a liquid crystal polymer and having a flow start temperature of 350 ° C. or higher. Here, the molding material is a liquid crystal polymer or a composition containing a liquid crystal polymer (hereinafter referred to as a liquid crystal polymer composition). And the flow start temperature of the said molding material becomes like this. Preferably it is 360-400 degreeC. By setting it to the lower limit value or more, the friction material is further improved in heat resistance and high-temperature strength, and it is possible to further suppress the occurrence of torque unevenness and waviness due to wear during operation of the vibration wave motor. Moreover, by setting it as an upper limit or less, a melting temperature and melt viscosity become low, the temperature required for the shaping | molding also becomes low, and shaping | molding workability improves more.

The flow start temperature is also referred to as flow temperature or flow temperature, and the molding material is heated at a rate of 4 ° C./min under a load of 9.8 MPa (100 kg / cm ² ) using a capillary rheometer. Is a temperature showing a viscosity of 4800 Pa · s (48000 poise) when extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, which is a measure of the molecular weight of the molding material (Naoyuki Koide, “ “Liquid Crystal Polymer—Synthesis / Molding / Application—”, CMC Co., Ltd., June 5, 1987, p. 95).

  The friction material 14 can be produced by molding the molding material. As the molding method, a melt molding method is preferable, and examples thereof include an injection molding method, an extrusion molding method such as a T-die method and an inflation method, a compression molding method, a blow molding method, a vacuum molding method, and a press molding method. . Among these, the injection molding method is preferable.

  The vibration wave motor 1 is configured such that a moving body 13 is brought into pressure contact with a vibrating body 12 by a known pressing means such as a spring tightening means (not shown).

  FIG. 3 is an enlarged view showing the main part of the vibration wave motor 1 shown in FIG. 2 along the protrusion 121. In FIG. 3, the laminated portion of the piezoelectric body 11, the vibration body 12, the friction material 14, and the moving body 13 is shown. The enlarged view corresponds to FIG. In FIG. 3, a part of the cross section is shown.

  When electric power is applied to the piezoelectric body 11, a traveling wave is generated in the vibrating body 12, and the moving body 13 moves due to the frictional force generated between the vibrating body 12 and the friction material 14.

  The vibration wave motor of the present invention is not limited to the one shown here, and a part of the configuration may be appropriately changed within a range that does not hinder the effects of the present invention. For example, here, the friction material is fixed to the surface of the moving body facing the vibrating body. However, the friction material may be fixed to the surface of the vibrating body facing the moving body.

Hereinafter, the molding material will be described in more detail.
In the vibration wave motor of the present invention, when the molding material is a liquid crystal polymer composition, components other than the liquid crystal polymer contained in the composition are not particularly limited, but are preferably fillers. By including the filler, the dimensional stability during molding is further improved, and the wear resistance is further improved by improving the strength of the friction material.

The filler may be a fibrous filler, a plate-like filler, or other granular filler such as a spherical shape other than the fibrous and plate-like shapes. The filler may be an inorganic filler or an organic filler.
Examples of fibrous inorganic fillers include glass fibers; carbon fibers such as pan-based carbon fibers and pitch-based carbon fibers; ceramic fibers such as silica fibers, alumina fibers and silica-alumina fibers; and metal fibers such as stainless steel fibers. . In addition, whiskers such as potassium titanate whisker, barium titanate whisker, wollastonite whisker, aluminum borate whisker, silicon nitride whisker, and silicon carbide whisker are also included.
Examples of fibrous organic fillers include polyester fibers and aramid fibers.
Examples of the plate-like inorganic filler include talc, mica, graphite, wollastonite, potassium titanate, glass flake, barium sulfate and calcium carbonate. Mica may be muscovite, phlogopite, fluorine phlogopite, or tetrasilicon mica.
Examples of the particulate inorganic filler include silica, alumina, titanium oxide, glass particles, glass balloons, boron nitride, silicon carbide, and calcium carbonate.
Among these, from the viewpoint of excellent wear resistance as a friction material, a more excellent effect of not damaging the surface of the vibrating body or moving body, more stable output performance and less change over time. The filler preferably has a Mohs hardness of 7 or less, preferably glass fiber or glass particles. Such a filler can be appropriately selected from commercially available products.
Only one type of filler may be used, or two or more types may be used in combination.
The content of the filler is preferably 0 to 100 parts by mass with respect to 100 parts by mass of the liquid crystal polymer.

  When the molding material is a liquid crystal polymer composition, examples of components other than the liquid crystal polymer contained in the composition include additives, resins other than the liquid crystal polymer, and the like in addition to the filler. These components may use only 1 type and may use 2 or more types together.

Examples of additives include antioxidants, heat stabilizers, ultraviolet absorbers, antistatic agents, surfactants, flame retardants, and colorants.
The content of the additive is preferably 0 to 5 parts by mass with respect to 100 parts by mass of the liquid crystal polymer.

Examples of resins other than liquid crystal polymers include thermoplastic resins such as polypropylene, polyamide, polyester, polysulfone, polyphenylene sulfide, polyether ketone, polycarbonate, polyphenylene ether, and polyetherimide; phenol resin, epoxy resin, polyimide resin, cyanate Examples thereof include resins that are thermosetting resins such as resins and that do not correspond to liquid crystal polymers.
The content of the resin other than the liquid crystal polymer is preferably 0 to 20 parts by mass with respect to 100 parts by mass of the liquid crystal polymer.

  The liquid crystal polymer composition is preferably prepared by melt-kneading the liquid crystal polymer and other components used as needed using an extruder and extruding the mixture into pellets. As the extruder, one having a cylinder, one or more screws arranged in the cylinder, and one or more supply ports provided in the cylinder is preferably used, and further one or more provided in the cylinder. Those having a bent portion are more preferably used.

  In the vibration wave motor of the present invention, the liquid crystal polymer is preferably liquid crystal polyester.

  The liquid crystalline polyester is a liquid crystalline polyester that exhibits liquid crystallinity in a molten state, and is preferably melted at a temperature of 450 ° C. or lower. The liquid crystal polyester may be a liquid crystal polyester amide, a liquid crystal polyester ether, a liquid crystal polyester carbonate, or a liquid crystal polyester imide. The liquid crystal polyester is preferably a wholly aromatic liquid crystal polyester using only an aromatic compound as a raw material monomer.

As a typical example of liquid crystal polyester,
(I) An aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, and at least one compound selected from the group consisting of an aromatic diol, an aromatic hydroxyamine, and an aromatic diamine are polymerized (polycondensed). thing,
(II) a polymer obtained by polymerizing plural kinds of aromatic hydroxycarboxylic acids,
(III) A polymer obtained by polymerizing an aromatic dicarboxylic acid and at least one compound selected from the group consisting of an aromatic diol, an aromatic hydroxyamine and an aromatic diamine,
(IV) What polymerizes polyester, such as a polyethylene terephthalate, and aromatic hydroxycarboxylic acid is mentioned. Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, the aromatic hydroxyamine, and the aromatic diamine are each independently replaced with a part or all of the polymerizable derivative. Also good.

Examples of polymerizable derivatives of a compound having a carboxyl group such as aromatic hydroxycarboxylic acid and aromatic dicarboxylic acid include those obtained by converting a carboxyl group into an alkoxycarbonyl group or an aryloxycarbonyl group (ester), carboxyl Examples include those obtained by converting a group into a haloformyl group (acid halide), and those obtained by converting a carboxyl group into an acyloxycarbonyl group (acid anhydride).
Examples of polymerizable derivatives of hydroxyl group-containing compounds such as aromatic hydroxycarboxylic acids, aromatic diols and aromatic hydroxyamines include those obtained by acylating hydroxyl groups and converting them to acyloxyl groups (acylated products) ).
Examples of polymerizable derivatives of amino group-containing compounds such as aromatic hydroxyamines and aromatic diamines include those obtained by acylating an amino group and converting it to an acylamino group (acylated product).

  The liquid crystalline polyester preferably has a repeating unit represented by the following general formula (1) (hereinafter sometimes referred to as “repeating unit (1)”). The repeating unit (1) and the following general formula (2) ) (Hereinafter sometimes referred to as “repeat unit (2)”) and a repeat unit represented by the following general formula (3) (hereinafter referred to as “repeat unit (3)”). More preferably).

(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
(3) ^-X-Ar 3 -Y-
(In the formula, Ar ¹ is a phenylene group, a naphthylene group or a biphenylylene group; Ar ² and Ar ³ are each independently a phenylene group, a naphthylene group, a biphenylylene group or a group represented by the following general formula (4): Yes; X and Y are each independently an oxygen atom or imino group; one or more hydrogen atoms in Ar ¹ , Ar ² and Ar ³ are each independently substituted with a halogen atom, an alkyl group or an aryl group May be.)
(4) -Ar ⁴ -Z-Ar ^5-
(In the formula, Ar ⁴ and Ar ⁵ are each independently a phenylene group or a naphthylene group; Z is an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)

As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, An n-heptyl group, a 2-ethylhexyl group, an n-octyl group, an n-nonyl group, and an n-decyl group may be mentioned, and the number of carbon atoms is preferably 1-10.
Examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group, and the carbon number thereof is 6 to 20. Is preferred.
When the hydrogen atom is substituted with these groups, the number is preferably 2 or less independently for each of the groups represented by Ar ¹ , Ar ² or Ar ^3. More preferably.

  Examples of the alkylidene group include a methylene group, an ethylidene group, an isopropylidene group, an n-butylidene group, and a 2-ethylhexylidene group, and preferably have 1 to 10 carbon atoms.

The repeating unit (1) is a repeating unit derived from a predetermined aromatic hydroxycarboxylic acid. As the repeating unit (1), Ar ¹ is a p-phenylene group (repeating unit derived from p-hydroxybenzoic acid), and Ar ¹ is a 2,6-naphthylene group (6-hydroxy-2). -Repeating units derived from naphthoic acid) are preferred.

The repeating unit (2) is a repeating unit derived from a predetermined aromatic dicarboxylic acid. As the repeating unit (2), Ar ² is a p-phenylene group (a repeating unit derived from terephthalic acid), Ar ² is an m-phenylene group (a repeating unit derived from isophthalic acid), Ar ² Is a 2,6-naphthylene group (a repeating unit derived from 2,6-naphthalenedicarboxylic acid), and Ar ² is a diphenyl ether-4,4′-diyl group (diphenyl ether- 4,4′-dicarboxylic acid-derived repeating units) are preferred.

The repeating unit (3) is a repeating unit derived from a predetermined aromatic diol, aromatic hydroxylamine or aromatic diamine. As the repeating unit (3), Ar ³ is a p-phenylene group (a repeating unit derived from hydroquinone, p-aminophenol or p-phenylenediamine), and Ar ³ is a 4,4′-biphenylylene group. Those (4,4′-dihydroxybiphenyl, 4-amino-4′-hydroxybiphenyl or repeating units derived from 4,4′-diaminobiphenyl) are preferred.

The content of the repeating unit (1) is the total amount of all repeating units constituting the liquid crystal polyester (the substance of each repeating unit is obtained by dividing the mass of each repeating unit constituting the liquid crystal polyester by the formula weight of each repeating unit). The equivalent amount (mole) is obtained, and the total value thereof) is preferably 30 mol% or more, more preferably 30 to 80 mol%, still more preferably 40 to 70 mol%, particularly preferably 45 to 65. Mol%.
The content of the repeating unit (2) is preferably 35 mol% or less, more preferably 10 to 35 mol%, still more preferably 15 to 30 mol%, based on the total amount of all repeating units constituting the liquid crystal polyester. Most preferably, it is 17.5-27.5 mol%.
The content of the repeating unit (3) is preferably 35 mol% or less, more preferably 10 to 35 mol%, still more preferably 15 to 30 mol%, based on the total amount of all repeating units constituting the liquid crystal polyester. Most preferably, it is 17.5-27.5 mol%.
The higher the content of the repeating unit (1), the easier it is to improve the melt fluidity, heat resistance, strength and rigidity. However, if the content is too large, the melting temperature and melt viscosity tend to increase, and the temperature required for molding increases. easy.

  The ratio between the content of the repeating unit (2) and the content of the repeating unit (3) is expressed as [content of repeating unit (2)] / [content of repeating unit (3)] (mol / mol). The ratio is preferably 0.9 / 1 to 1 / 0.9, more preferably 0.95 / 1 to 1 / 0.95, and still more preferably 0.98 / 1 to 1 / 0.98.

  In addition, liquid crystalline polyester may have 2 or more types of repeating units (1)-(3) each independently. The liquid crystal polyester may have a repeating unit other than the repeating units (1) to (3), and the content thereof is preferably 10 with respect to the total amount of all repeating units constituting the liquid crystal polyester. The mol% or less, more preferably 5 mol% or less.

  The liquid crystal polyester preferably has, as the repeating unit (3), X and Y each having an oxygen atom, that is, a repeating unit derived from a predetermined aromatic diol. As the repeating unit (3), More preferably, X and Y each have only an oxygen atom. By doing in this way, liquid crystalline polyester tends to become low in melt viscosity.

  The liquid crystal polyester is preferably produced by melt polymerization of raw material monomers corresponding to the repeating units constituting the liquid crystal polyester and solid-phase polymerization of the obtained polymer (prepolymer). Thereby, high molecular weight liquid crystal polyester having high heat resistance, strength and rigidity can be produced with good operability. Melt polymerization may be carried out in the presence of a catalyst. Examples of the catalyst in this case include metals such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide. Compounds, nitrogen-containing heterocyclic compounds such as 4- (dimethylamino) pyridine, 1-methylimidazole and the like can be mentioned, and nitrogen-containing heterocyclic compounds are preferably used.

  The liquid crystal polyester has a flow start temperature of preferably 350 ° C. or higher, more preferably 360 ° C. to 400 ° C. As the flow start temperature is higher, the heat resistance, strength, and rigidity are more likely to be improved. However, if the flow start temperature is too high, the melting temperature and the melt viscosity are likely to be high, and the temperature required for the molding is likely to be high.

When obtaining a liquid crystalline polyester having a flow initiation temperature of 350 ° C. or higher, for example, when it has an m-phenylene group as a repeating unit derived from isophthalic acid, the inclusion of the m-phenylene group The ratio is preferably 3 mol% or less. Moreover, when it has a 2, 6- naphthylene group as a repeating unit, it is preferable that the content rate of the 2, 6- naphthylene group shall be 3 mol% or less or 45 mol% or more.
Specifically, the liquid crystalline polyester is composed of repeating units (1), (2) and (3), the repeating unit (1) is derived from p-hydroxybenzoic acid, and the repeating unit (2) is terephthalic acid. In the case of a quaternary system in which the repeating unit derived from isophthalic acid and the repeating unit (3) are composed of a repeating unit derived from 4,4′-dihydroxybiphenyl, the content of the repeating unit derived from isophthalic acid is selected from the liquid crystal polyester. It is preferable to set it as 3 mol% or less with respect to the total amount of all the repeating units which comprise. The liquid crystalline polyester is composed of repeating units (1), (2) and (3), and the repeating unit (1) is a repeating unit derived from p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, a repeating unit ( In the case of a quaternary system in which 2) is a repeating unit derived from terephthalic acid and the repeating unit (3) is a repeating unit derived from 4,4′-dihydroxybiphenyl, it is derived from 6-hydroxy-2-naphthoic acid. The content of the repeating unit is preferably 3 mol% or less or 45 mol% or more with respect to the total amount of all repeating units constituting the liquid crystal polyester.

  The vibration wave motor of the present invention includes, for example, a communication device such as a mobile phone; a toy / model such as a game machine; an audio / video device such as a CD player or a digital video camera; a home appliance such as a hair dryer or a drill; Optical and precision equipment such as copiers, copiers, digital cameras, etc .; automotive electrical equipment for power windows, mirror drive, etc .; air conditioning equipment; measuring equipment; medical equipment; industrial robots, submarine exploration robots, disaster rescue / support robots, etc. It can be widely applied to other robots.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples. In addition, the flow start temperature of liquid crystalline polyester and liquid crystalline polyester composition was measured with the following method.

(Measurement of flow start temperature)
Using a flow tester (manufactured by Shimadzu Corporation, CFT-500 type), about 2 g of liquid crystal polyester or liquid crystal polyester composition is filled into a cylinder equipped with a die having a nozzle having an inner diameter of 1 mm and a length of 10 mm, and 9.8 MPa. While raising the temperature at a rate of 4 ° C./min under a load of (100 kg / cm ² ), the liquid crystal polyester or the liquid crystal polyester composition is melted and extruded from a nozzle, and the temperature showing a viscosity of 4800 Pa · s (48000 poise) is obtained. It was measured.

<Manufacture of liquid crystal polyester>
[Production Example 1]
In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer and reflux condenser, p-hydroxybenzoic acid 828.8 g (6.0 mol), terephthalic acid 473.4 g (2.85 mol) , 24.9 g (0.15 mol) of isophthalic acid, 4,4′-dihydroxybiphenyl 558.6. g (3.0 mol) and 1347.6 g (13.2 mol) of acetic anhydride were added, and the mixture was stirred at room temperature under a nitrogen gas stream for 15 minutes and sufficiently purged with nitrogen, and then stirred at room temperature to 145 ° C. The temperature was raised over 30 minutes and the mixture was refluxed at 145 ° C. for 3 hours. Next, while distilling off by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 145 ° C. to 320 ° C. over 2 hours and 50 minutes, held at 320 ° C. for 1 hour, and then the contents were taken out from the reactor, Cooled to room temperature. The obtained solid was pulverized with a pulverizer to obtain a powdery prepolymer. The flow initiation temperature of this prepolymer was 258 ° C. Next, the prepolymer was heated from room temperature to 250 ° C. over 1 hour in a nitrogen gas atmosphere, heated from 250 ° C. to 285 ° C. over 5 hours, and held at 285 ° C. for 3 hours, thereby solidifying the prepolymer. After the phase polymerization, the mixture was cooled to obtain a powdery liquid crystal polyester. The liquid crystal polyester had a flow start temperature of 382 ° C. Hereinafter, this liquid crystal polyester is referred to as LCP1.

[Production Example 2]
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 994.5 g (7.2 mol) of p-hydroxybenzoic acid and 358.8 g (2.16 mol) of terephthalic acid , 39.9 g (0.24 mol) of isophthalic acid, 446.9 g (2.4 mol) of 4,4′-dihydroxybiphenyl, 1347.6 g (13.2 mol) of acetic anhydride and 0.194 g of 1-methylimidazole. The mixture was stirred at room temperature in a nitrogen gas stream for 15 minutes and sufficiently purged with nitrogen. After stirring, the temperature was raised from room temperature to 145 ° C. over 30 minutes and refluxed at 145 ° C. for 1 hour. Next, while distilling off by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 145 ° C. to 320 ° C. over 2 hours and 50 minutes, held at 320 ° C. for 1 hour, and then the contents were taken out from the reactor, Cooled to room temperature. The obtained solid was pulverized with a pulverizer to obtain a powdery prepolymer. The flow initiation temperature of this prepolymer was 258 ° C. Next, the prepolymer was heated from room temperature to 250 ° C. over 1 hour in a nitrogen gas atmosphere, heated from 250 ° C. to 285 ° C. over 5 hours, and held at 285 ° C. for 3 hours, thereby solidifying the prepolymer. After the phase polymerization, the mixture was cooled to obtain a powdery liquid crystal polyester. The liquid crystal polyester had a flow start temperature of 362 ° C. Hereinafter, this liquid crystal polyester is referred to as LCP2.

[Production Example 3]
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 994.5 g (7.2 mol) of p-hydroxybenzoic acid and 299.0 g (1.8 mol) of terephthalic acid , 99.7 g (0.6 mol) of isophthalic acid, 446.9 g (2.4 mol) of 4,4′-dihydroxybiphenyl, 1347.6 g (13.2 mol) of acetic anhydride and 0.194 g of 1-methylimidazole. The mixture was stirred at room temperature in a nitrogen gas stream for 15 minutes and sufficiently purged with nitrogen. After stirring, the temperature was raised from room temperature to 145 ° C. over 30 minutes and refluxed at 145 ° C. for 1 hour. Next, while distilling off by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 145 ° C. to 320 ° C. over 2 hours and 50 minutes, held at 320 ° C. for 1 hour, and then the contents were taken out from the reactor, Cooled to room temperature. The obtained solid was pulverized with a pulverizer to obtain a powdery prepolymer. The flow initiation temperature of this prepolymer was 261 ° C. Next, the prepolymer was heated from room temperature to 250 ° C. over 1 hour in a nitrogen gas atmosphere, heated from 250 ° C. to 285 ° C. over 5 hours, and held at 285 ° C. for 3 hours, thereby solidifying the prepolymer. After the phase polymerization, the mixture was cooled to obtain a powdery liquid crystal polyester. The liquid crystal polyester had a flow initiation temperature of 327 ° C. Hereinafter, this liquid crystal polyester is referred to as LCP3.

<Production of liquid crystal polyester composition>
[Production Example 4]
LCP1 (100 parts by mass) and glass fiber (“EFH75-01” manufactured by Central Glass Co., Ltd.) (44 parts by mass) were mixed using a Henschel mixer, and the resulting mixture was mixed with a twin-screw extruder (Ikegai Iron Works). The product was granulated at a cylinder temperature of 400 ° C. using “PCM-30” manufactured by the company to obtain pellets of a liquid crystal polyester composition. The flow starting temperature of this liquid crystal polyester composition was 380 ° C. Hereinafter, this liquid crystal polyester composition is referred to as LCP4.

[Production Example 5]
LCP3 (100 parts by mass) and glass fiber (“EFH75-01” manufactured by Central Glass Co., Ltd.) (44 parts by mass) were mixed using a Henschel mixer, and the resulting mixture was mixed with a twin-screw extruder (Ikegai Iron Works). The product was granulated at a cylinder temperature of 360 ° C. using “PCM-30” manufactured by the company to obtain pellets of a liquid crystal polyester composition. The liquid crystal polyester composition had a flow start temperature of 322 ° C. Hereinafter, this liquid crystal polyester composition is referred to as LCP5.

[Production Example 6]
LCP1 (100 parts by mass) and carbon fiber (Molded carbon fiber “HTACMF-0160-0H” manufactured by Toho Tenax Co., Ltd.) (44 parts by mass) were mixed using a Henschel mixer, and the resulting mixture was mixed biaxially. Using an extruder ("PCM-30" manufactured by Ikekai Tekko Co., Ltd.), granulation was performed at a cylinder temperature of 400 ° C to obtain pellets of a liquid crystal polyester composition. The flow starting temperature of this liquid crystal polyester composition was 380 ° C. Hereinafter, this liquid crystal polyester composition is referred to as LCP6.

<Manufacture of vibration wave motor>
[Example 1]
The vibration wave motor shown in FIG. 2 was produced. The piezoelectric body, the vibrating body, and the moving body were all disk-shaped with a diameter of 50 mm, and the entire thickness was 3 mm. Both the vibrating body and the moving body were made of stainless steel. Further, the LCP1 is dried at 180 ° C. for 12 hours using a hot air circulation dryer, and then injection molded using an injection molding machine (“PS40E-5ASE type” manufactured by Nissei Plastic Industry Co., Ltd.). A 1 mm friction material was obtained. The cylinder temperature at the time of injection molding was set to 400 ° C. The moving body was brought into pressure contact with the vibrating body via a friction material by tightening with a spring to obtain a vibration wave motor.

[Example 2]
A vibration wave motor was produced in the same manner as in Example 1 except that LCP2 was used instead of LCP1 and the cylinder temperature during injection molding was changed to 380 ° C instead of 400 ° C.

[Example 3]
A vibration wave motor was produced in the same manner as in Example 1 except that LCP4 was used instead of LCP1.

[Example 4]
A vibration wave motor was produced in the same manner as in Example 1 except that LCP6 was used instead of LCP1.

[Comparative Example 1]
A vibration wave motor was produced in the same manner as in Example 1 except that LCP3 was used instead of LCP1 and the cylinder temperature during injection molding was changed to 360 ° C instead of 400 ° C.

[Comparative Example 2]
A vibration wave motor was produced in the same manner as in Example 1 except that LCP5 was used instead of LCP1 and the cylinder temperature during injection molding was changed to 360 ° C instead of 400 ° C.

<Characteristic evaluation of vibration wave motor>
With respect to the vibration wave motors of the above examples and comparative examples, the electrodes were arranged so that traveling waves were excited in the circumferential direction, and set to a predetermined pressure. Then, the motor is operated by applying a resonance frequency of about 70 kHz and an input current of 600 mA, and the fluctuation of the rotation speed at the time of no-load operation between the initial stage (at the start of operation) and the continuous operation for 100 hours from the initial stage. The variation in the starting torque, the surface state of the protrusion of the vibrating body, and the squeal were evaluated according to the following criteria. The results are shown in Table 1.

(Fluctuations in rotation speed during no-load operation)
○: No change.
Δ: Slight fluctuation, but no problem in practical use.
X: There is a large fluctuation.
(Starting torque fluctuation)
○: No change.
Δ: Slight fluctuation, but no problem in practical use.
X: There is a large fluctuation.
(Surface condition of the protrusion of the vibrator)
○: No scratches are seen.
X: A clear crack is seen.
(Scream)
○: There is a noise.
X: There is no squeal.

As is clear from Table 1, the vibration wave motors of Examples 1 to 4 have good results for all items, the fluctuations in the rotational speed and the starting torque are suppressed, and the occurrence of squeal is also suppressed. It was. In particular, the characteristics of the vibration wave motors of Examples 1 to 3 were excellent.
In contrast, the vibration wave motors of Comparative Examples 1 and 2 were not satisfactory in all items. In particular, in Comparative Example 1, rotation unevenness occurred in a short time from the start of operation. In any of the comparative examples, a squeal that was considered to be caused by wear of the friction material occurred.

  DESCRIPTION OF SYMBOLS 1 ... Vibration wave motor, 11 ... Piezoelectric body, 12 ... Vibration body, 12a ... The surface which opposes the moving body of a vibrating body, 13 ... Moving body, 13a ... With the vibrating body of a moving body Opposing surface, 14 ... friction material

Claims (5)

A vibration wave motor that moves a moving body by using a frictional force generated by the traveling wave by pressing the moving body through a friction material to a vibrating body that generates a traveling wave on a surface,
The friction material is fixed to a surface of the vibrating body or moving body facing each other,
The vibration wave motor is characterized in that the friction material is a molded body containing a liquid crystal polymer and having a flow start temperature of 350 ° C. or higher.   2. The vibration wave motor according to claim 1, wherein the liquid crystal polymer is liquid crystal polyester.   The vibration wave motor according to claim 1, wherein the molding material further includes a filler.   The vibration wave motor according to claim 3, wherein the filler has a Mohs hardness of 7 or less.   The vibration wave motor according to claim 3 or 4, wherein the filler is glass fiber or glass particles.

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