JP2003018870A - Ultrasonic motor and guide device using ultrasonic motor as drive source of movable body - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To suppress wear and shedding of a pressing member provided in an ultrasonic motor, improve the life, obtain a stable contact state with a movable body, and obtain an appropriate frictional force with the movable body. To be obtained. A pressing member of an ultrasonic motor is formed of an alumina sintered body containing alumina as a main component and titanium carbide as a subcomponent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultrasonic motor,
The present invention relates to a guide device in which a movable body that moves linearly or rotates is driven by an ultrasonic motor, and is particularly suitable as a guide device used in precision processing machines, precision measuring devices, and semiconductor manufacturing devices.

[0002]

2. Description of the Related Art Ultrasonic motors have the characteristics that the minimum amplitude is small, on the order of nanometers, high-resolution positioning is possible, and because the friction drive is large, the driving force is large. It has been put to practical use in rotary motion systems such as zoom mechanisms and vibration alarms in wristwatches, and recently it has been attempted to be applied to linear motion systems.

For example, as shown in FIGS. 3A and 3B as an example of a conventional ultrasonic motor, the ultrasonic motor 31 is
The piezoelectric ceramic plate 32 has four divided electrode films 33a, 33b, 33c and 33d on one main surface thereof, and the electrode films 33a and 33d located diagonally are connected to each other.
By connecting the electrode films 33b and 33c diagonally located,
On the other main surface, a vibrating body 35 having an electrode film 34 formed on almost the entire surface thereof and a pressing member 36 provided on the end surface of the piezoelectric ceramic plate 32 are provided, and the electrode film 33a formed on the one main surface. By applying voltages having different phases to the electrode film 33b and the electrode film 34b and grounding the electrode film 34 formed on the other main surface, longitudinal vibration and lateral vibration are generated in the piezoelectric ceramic plate 32, and these vibrations are generated. Therefore, the pressing member 36 is caused to move in an elliptical manner.

Further, as shown in FIG. 4 as an example of a guide device using a conventional ultrasonic motor 31 as a drive source of a movable body, this guide device has a pair of guide members such as a cross roller guide on a base board 11. 12 and these guide members 1
The stage 13 as a movable body is linearly guided by 2.

A driving force transmission member 14 is installed on one side surface of the stage 13, and a linear scale 15 is installed on the other side surface of the stage 13, and a measuring head 16 is installed at a position facing the linear scale 15. The position detecting means 17 is provided to configure the driving force transmitting member 1
4 is an ultrasonic motor 31 perpendicular to its longitudinal direction.
The pressing member 36 is brought into contact with the pressing member 36, and the position information from the position detecting means 17 associated with the movement of the stage 13 and the reference position information based on the preset movement profile of the stage 13 change depending on the deviation. Based on the parameters, the control unit 18 performs, for example, PID calculation processing, and the driver 1
By performing feedback control for outputting a command signal to the ultrasonic motor 31 to the ultrasonic motor 31, the ultrasonic motor 31 is driven according to the command signal, and the stage 13 is guided to the guide member 12 by frictional driving with the pressing member 36. It was supposed to be moved along. 20 is an ultrasonic motor 31
And the ultrasonic motor 31 is a case 2
In 0, it is sandwiched by four springs 21,
The pressing member 36 of the ultrasonic motor 31 is pressed against the driving force transmitting member 14 by the spring 22 provided between the rear end of the ultrasonic motor 31 and the case 20. Reference numeral 23 is a load cell for measuring the pressing force of the ultrasonic motor 31.

Since the pressing member 36 of the ultrasonic motor 31 slides while being pressed against the driving force transmitting member 14, it must be formed of a material having excellent wear resistance. A glass material such as glass or soda glass, or a ceramic sintered body having an alumina content of 99.5% by weight or more, such as an alumina sintered body, a zirconia sintered body, or a silicon carbide sintered body. (Japanese Patent Laid-Open No. 7-273384).

[0007]

However, in the case where the pressing member 36 of the ultrasonic motor 31 is made of a glass material such as quartz glass or soda glass, the fracture toughness value is small, and when cracks occur, chips or cracks occur. There was a problem that it was easy. Therefore, when an attempt is made to move the heavy stage 13 with the ultrasonic motor 31 having the glass pressing member 36, the pressing member 36 may be chipped due to the stress acting during frictional driving with the driving force transmitting member 14. Cracks occur,
There was a problem that the guide device had to be stopped each time. Moreover, when the ultrasonic motor 31 is driven at a high speed, the frictional heat with the driving force transmission member 14 may reach such a high temperature that it exceeds the softening point of the glass material forming the pressing member 36. There was also a problem that it was difficult to apply.

On the other hand, the pressing member 36 of the ultrasonic motor 31
In addition, although a ceramic sintered body made of alumina, zirconia, or silicon carbide is less likely to be damaged than a glass material, a silicon carbide-based sintered body used as the pressing member 36 has a different material. Due to the self-lubricating action, the friction coefficient with the driving force transmission member 14 is small, and the ultrasonic motor 31
However, there is a problem in that the stage 13 cannot be moved at high speed due to slippage when driven at high speed.

Further, in the case of using the zirconia-based sintered body for the pressing member 36, the Vickers hardness is as small as about 12 GPa as compared with other ceramic sintered bodies, so that comparison is made by friction driving with the driving force transmitting member 14. There was a problem that it wears out in a very short period of time. Moreover, when the ultrasonic motor 31 is driven at a high speed, the frictional heat with the driving force transmission member 14 may exceed 100 ° C., and the zirconia sintered body is generally weak to heat, so that the mechanical properties and the like are deteriorated. There was a fear that the wear would be accelerated by this.

Further, when the pressing member 36 is made of an alumina-based sintered body having an alumina content of 99.5% by weight or more, it has a relatively high hardness, but it is a commonly used alumina-based sintered body. There are Calcia, Magnesia,
The sintering aid such as silica is contained in an amount of about 1 to 2% by weight, and cracks are generated in the grain boundary layer made of the above-mentioned sintering aid due to the stress acting at the time of friction driving with the driving force transmitting member 14 to cause alumina. Particles are shattered, and scratches are generated in the driving force transmission member 14 due to the edges of the recessed parts, or the shattered powder is caught between the driving force transmission member 14 and the pressing member 36 or the driving force transmission. There is a problem that the member 14 is scraped and worn. Moreover, when the shattered powder is caught in the driving force transmission member 14, the contact state changes, which may adversely affect the movement characteristics and positioning accuracy of the stage 13 and shorten the life of the apparatus. there were.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic motor which is free from mechanical deterioration due to frictional heat, has excellent wear resistance and does not slip even when driven at a high speed. By providing this ultrasonic motor as a drive source for a movable body,
It is an object of the present invention to provide a guide device capable of moving a movable body at high speed, obtaining stable drive characteristics, and having a long life.

Another object of the present invention is to provide an ultrasonic motor which can be used also in a guide device that does not like magnetic materials.

[0013]

In view of the above problems, the present invention provides an ultrasonic motor comprising a vibrating body and a pressing member for transmitting the vibration of the vibrating body to the movable body side. It is characterized in that it is formed of an alumina-based sintered body containing as a main component and titanium carbide as a subcomponent.

The content of titanium carbide in the alumina-based sintered body is preferably 10 to 50% by weight, and
It is preferable that the maximum grain size of the alumina crystal and the titanium carbide crystal in the alumina sintered body is 4 μm or less, and the maximum pore diameter of the alumina sintered body is 2 μm or less.

Further, the alumina sintered body contains a paramagnetic metal oxide as an auxiliary component in a range of 0.05 to 7% by weight, and the maximum magnetic flux density of the alumina sintered body is 0.
It is preferable to use one having a thickness of 05 μT or less.

According to the present invention, the pressing member of the ultrasonic motor is disposed in contact with the movable body, and the vibration of the ultrasonic motor is transmitted through the pressing member to frictionally drive the movable body. A guide device using a sound wave motor as a drive source for the movable body is configured.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

1A and 1B are views showing an example of an ultrasonic motor according to the present invention. FIG. 1A is a front view thereof, and FIG. 1B is a rear view thereof.

This ultrasonic motor 1 is a multi-mode ultrasonic motor, and is divided into four main surfaces of a piezoelectric ceramic plate 2 made of, for example, lead zirconate titanate, barium titanate, lithium niobate or the like. Electrode films 3a, 3b, 3
c and 3d are provided, and the electrode film 3a and the electrode film 3 are diagonally located.
In addition to connecting d, the electrode film 3b and the electrode film 3c which are diagonally connected are connected, and the vibrating body 5 in which the electrode film 4 is formed on substantially the entire main surface of the other side, and the piezoelectric ceramic plate 2 described above.
And a pressing member 6 provided on the end surface of the pressing member 6,
It is formed of an alumina-based sintered body containing alumina as a main component and titanium carbide as a sub-component.

Then, a voltage having a phase difference of 90 degrees is applied to the electrode film 3a and the electrode film 3b formed on the one main surface, and the electrode film 4 formed on the other main surface.
Is grounded to generate longitudinal vibration and transverse vibration in the piezoelectric ceramic plate 2, and the pressing member 6 is caused to make an elliptical motion in a certain direction by combining these vibrations, and the electrode film 3a and the electrode film 3
By applying a voltage whose phase is inverted to b, the pressing member 6 can be made to move in an elliptic direction in the opposite direction.

FIG. 2 is a plan view showing an example of a guide device using the ultrasonic motor 1 of the present invention as a drive source for a movable body. This guide device is a pair of guides such as a cross roller guide on a base board 11. The guide member 12 is provided, and the stage 13 as a movable body is linearly guided by these guide members 12.

A driving force transmission member 14 is installed on one side surface of the stage 13, and a linear scale 15 is installed on the other side surface of the stage 13.
5, a measuring head 16 is provided at a position opposite to 5 to form a position detecting means 17, and the driving force transmitting member 14 is also provided.
Is pressed against the pressing member 6 of the ultrasonic motor 1 perpendicularly to the longitudinal direction of the ultrasonic motor 1, and the positional information from the position detecting means 17 accompanying the movement of the stage 13 and the preset stage 13 are detected. The control unit 18 is based on the parameter that changes according to the deviation from the reference position information based on the movement profile.
In, for example, by performing PID calculation processing and performing feedback control to output a command signal to the ultrasonic motor 1 to the driver 19, the ultrasonic motor 1 is caused to elliptically vibrate according to the command signal, and the ultrasonic motor 1 The stage 13 is moved along the guide member 12 by frictional driving of the pressing member 6 and the driving force transmission member 14 of the stage 13.

Reference numeral 20 denotes a case for accommodating the ultrasonic motor 1, and the ultrasonic motor 1 is provided in the case 20.
A spring 2 which is sandwiched by four springs 21 and which is installed between the rear end of the ultrasonic motor 1 and the case 20.
2, the pressing member 6 of the ultrasonic motor 1 is pressed against the driving force transmitting member 14. Reference numeral 23 is a load cell for measuring the pressing force of the ultrasonic motor 31.

According to the present invention, the ultrasonic motor 1
The pressing member 6 was made of alumina having a high hardness and a high melting point (Vickers hardness (H _v ): 18 GPa, melting point: 2100).
° C.) as a main component, a higher hardness than alumina as a secondary component, a high melting point, and titanium carbide having a high tenacity (Vickers hardness (H _v): 28 GPa mp: 3200 ° C. fracture toughness: the 6MPam ^1/2) Since it is formed of the contained alumina sintered body, the frictional drive with the driving force transmitting member 14 makes it difficult for the abutting surface of the pressing member 6 to wear, and it is difficult for the driving force transmitting member 14 to be shredded or cracked. It is possible to reduce the wear of the wearer, suppress wear of the wearer, and constantly stabilize the contact state for a long period of time. Moreover, when the alumina-based sintered body forming the pressing member 6 is slid at high speed with the driving force transmitting member 14, a chemo-mechanical reaction in which titanium carbide reacts with oxygen in the atmosphere due to frictional heat occurs, and alumina or Since titanium oxide having a friction coefficient larger than that of titanium carbide can be generated on the contact surface of the pressing member 6, even if the ultrasonic motor 1 is driven at high speed, the pressing member 6 and the driving force transmitting member 14 can be connected to each other. The stage 13 can be moved at high speed with almost no slippage.

By the way, the content of titanium carbide in the alumina sintered body forming the pressing member 6 is preferably 10 to 50% by weight. This is because when the content of titanium carbide is less than 10% by weight, the effect of improving mechanical properties such as hardness, strength and toughness of the alumina sintered body is small, and the ultrasonic motor 1 is driven at high speed. When the content of titanium carbide exceeds 50% by weight, hardness decreases when exposed to high temperatures. When the friction drive with the force transmission member 14 extends for a long time,
This is because the pressing member 6 is worn away.

Further, in the above-mentioned alumina-based sintered body, in addition to alumina as a main component and titanium oxide as a subcomponent, Mg, Zr, Si, Y are added as auxiliary components such as a sintering auxiliary.
b, oxides such as Mg, Zr, Si,
Since Yb and the like are paramagnetic metals, when the content of this oxide becomes too large, the alumina-based sintered body becomes magnetic, and when the content of paramagnetic metal oxide exceeds 7% by weight. In addition, the hardness of the alumina-based sintered body decreases, and it becomes impossible to maintain a high Vickers hardness (H _v ) of 19 GPa or more, and the maximum magnetic flux density of the alumina-based sintered body is 0.05.
It cannot be used in applications where μT is exceeded and magnetic materials are disliked, for example, in guide devices such as electron beam exposure devices. Therefore, the content of the paramagnetic metal oxide contained as an auxiliary component is preferably 7% by weight or less. However, when the content of paramagnetic metal oxide is less than 0.1% by weight,
It becomes difficult to obtain a sintered body.

Therefore, the content of the paramagnetic metal oxide contained as an auxiliary component may be 0.1 to 7% by weight,
If contained in this range, the Vickers hardness (H _v ) is 19
High hardness of GPa or higher is maintained and the maximum magnetic flux density is set to 0.
It can be set to 05 μT or less.

The balance consists essentially of alumina. It is an unavoidable impurity contained in alumina as a main component, titanium carbide as a subcomponent, paramagnetic metal oxide as a sintering aid, and the like. A small amount may be mixed if it exists.

The maximum grain size of the alumina crystal and titanium carbide crystal in the alumina sintered body is 4 μm.
In addition to the following, it is preferable to set the maximum pore diameter of the alumina-based sintered body to 2 μm or less.

Here, the maximum grain size of each of the alumina crystal and the titanium carbide crystal is set to 4 μm or less. When the maximum grain size of each crystal grain exceeds 4 μm, if the shedding or cracking occurs, the pressing member 6 is pressed. This is because a large concave portion is formed on the abutting surface of the above, the driving force transmitting member 14 is easily damaged, and the pressing member 6 is worn more, and the maximum pore diameter of the alumina sintered body is increased. The reason why it is set to 2 μm or less is that if the maximum pore diameter exceeds 2 μm, grain breakage and cracking are likely to occur.

Further, if the surface roughness of the contact surface of the pressing member 6 with the driving force transmitting member 14 is rough, scratches or the like will be generated in the driving force transmitting member 14 which is a mating member in the initial fitting process, and wear will occur. Rapidly progresses, the contact surface of the pressing member 6 is abraded severely. Therefore, the contact surface of the pressing member 6 has an arithmetic mean roughness (Ra) of 0.2 μm.
It is preferably set to m or less.

By the way, in order to obtain an alumina-based sintered body containing alumina as a main component and titanium carbide as a secondary component as described above, 50 to 90 alumina powder having a particle size of 0.3 to 0.6 μm is used. % By weight, particle size 0.3-0.6 μm
A mixture of 10 to 50% by weight of titanium carbide powder, and 0.1 to 7% by weight of a total of oxides of paramagnetic metals such as Mg, Zr, Si and Yb which are sintering aids. A slurry of powder is prepared and uniaxial pressure molding method, isostatic molding method,
It can be obtained by molding into a predetermined shape by a well-known ceramic molding method such as an injection molding method, and then firing at a temperature of 1600 to 1750 ° C. for about 1 to 2 hours in a vacuum atmosphere. Further, by applying a pressure of about 20 to 40 MPa during firing, the maximum grain size of the alumina crystal or titanium carbide crystal can be 4 μm or less, and the maximum pore size of the alumina sintered body can be 2 μm or less.

If the alumina sintered body obtained under such conditions is used as the pressing member 6 of the ultrasonic motor 1 and the ultrasonic motor 1 is mounted on the guide device, the driving force of the stage 13 is transmitted. In the friction drive with the member 14,
Not only is the wear of the pressing member 6 small, but also the wear of the driving force transmission member 14 that is a mating member can be suppressed, and the occurrence of scratches and the like can be reduced, so that the guide device can be driven for a long period of time. Together with the pressing member 6
Since it is possible to reduce the presence of shattered powder between the driving force transmitting member 14 and the driving force transmitting member 14, it is possible to stabilize the contact state between the pressing member 6 and the driving force transmitting member 14, and to move the stage 13 during movement. Titanium oxide having a larger friction coefficient than alumina or titanium carbide is generated on the surface of the pressing member 6 made of an alumina-based sintered body due to frictional heat with the driving force transmitting member 14 without adversely affecting accuracy and positioning accuracy. Therefore, even if the driving force of the ultrasonic motor 1 is increased in order to move the stage 13 at high speed, slippage does not occur, so that the stage 13 can be further speeded up.

In the above, the embodiment of the present invention has been described by taking the multimode ultrasonic motor 1 as an example. However, in the present invention, a standing wave type of a single vibration mode, a traveling wave type, or a plurality of vibration mode modes is used. It goes without saying that the present invention can also be applied to conversion type and composite vibration type ultrasonic motors.

In FIG. 2, the guide device in which the stage 13 moves linearly has been described as an example, but the present invention can be applied to a guide device in which the movable body rotates.

As described above, it goes without saying that the present invention can be applied to the ones which are improved or changed without departing from the gist thereof.

[0037]

EXAMPLE Here, the pressing member 6 in the ultrasonic motor 1 of FIG. 1 is mainly composed of quartz glass, a high-purity alumina sintered body, a zirconia sintered body, a silicon carbide sintered body, and alumina. In the alumina sintered body formed of an alumina-based sintered body containing titanium carbide as a secondary component, and containing alumina as a main component and titanium carbide as a secondary component, the content of titanium carbide, and Prepared ones having different amounts of auxiliary components, the amount of wear of the pressing member 6 when the prepared ultrasonic motor 1 was incorporated into the guide device of FIG. 2 and driven, and the driving force transmission member which is a counterpart member An experiment was conducted to examine the amount of wear of No. 14.

In this experiment, the size of the piezoelectric ceramic plate 2 constituting the vibrating body 5 of the ultrasonic motor 1 was set to be 3
0 mm, width 7.5 mm, thickness 3 mm and formed of lead zirconate titanate-based piezoelectric ceramics are used, and the size of the pressing member 6 joined to the piezoelectric ceramic plate 2 is 4.2 mm in length and diameter. The cylinder was 3 mm, and the contact surface was a spherical surface having a radius of curvature of 7 mm.

Further, the guide member 12 constituting the guide device.
For this, a cross roller guide having a stroke of 100 mm was used, and the stage 13 having a weight of 5 kg was moved via the guide member 12. In addition, the driving force transmission member 14 that contacts the pressing member 6 of the ultrasonic motor 1
An alumina sintered body having an alumina content of 99% by weight and a Vickers hardness of 15.2 GPa is used as
Moreover, the contact surface with the pressing member 6 has an arithmetic average roughness (Ra) of 0.05 μm.

The profile of the stage 13 set in advance in the control unit 18 is a trapezoidal control in which the moving distance is 100 mm, the acceleration / deceleration is 0.03 G, and the maximum speed is 100 mm / s, and the ultrasonic motor 1 is driven at 40 kHz. It was made to drive at the frequency. Then, the amount of wear of the pressing member 6 and the amount of wear of the driving force transmission member 14 after driving the stage 13 for 500 km under these conditions were measured.

Before starting the experiment, the contact surface of the pressing member 6 with the driving force transmitting member 14 was observed with a scanning electron microscope at a magnification of 2000, and the crystal grains and the maximum air pressure on the contact surface were observed. A rectangular parallelepiped having a length of 3 mm, a width of 3 mm, and a thickness of 1.2 mm is made from the same material as the material forming the pressing member 6 while measuring the hole diameter, and an alternating magnetometer (Tokyo Instruments 2900-04C type) is used. The maximum magnetic flux density was measured.

The respective results are shown in Table 1.

[0043]

[Table 1]

As is clear from Table 1, the ultrasonic motor 1
Sample No. 1 in which the pressing member 6 was made of an alumina-based sintered body containing alumina as a main component and titanium carbide as a subcomponent. 5 to 32 are pressing members 6 of the ultrasonic motor 1.
Of quartz glass, a high-purity alumina sintered body, a zirconia sintered body, and a silicon carbide sintered body. 1 to
It can be seen that the wear of the pressing member 6 and the driving force transmitting member 14 can be suppressed as compared with the case of No. 4.

As a result, in order to increase the life of the ultrasonic motor 1 and suppress the wear of the mating member, the pressing member 6 of the ultrasonic motor 1 is made of alumina containing alumina as a main component and titanium carbide as a sub-component. It is understood that it is sufficient to use the one formed of the quality sintered body. Sample No. 5
It was also confirmed that a titanium oxide film was formed on the abutting surfaces of the pressing members 6 to 32, and the titanium oxide film increased the frictional force.

When the pressing member 6 of the ultrasonic motor 1 is formed of an alumina-based sintered body containing alumina as a main component and titanium carbide as a secondary component, the alumina-based sintered body will be described. Titanium carbide content in 10-5
Sample No. 8 to 10 and sample No. 24
Sample Nos. 26 to 26 having a titanium carbide content exceeding the above range. 5 to 7 and sample No. It is understood that the wear amounts of the pressing member 6 and the driving force transmission member 14 can be further suppressed as compared with Nos. 21 to 23.

Sample No. 2 in which the maximum grain size of alumina crystals and titanium carbide crystals in the alumina sintered body was 4 μm or less and the maximum pore diameter of the alumina sintered body was 2 μm or less. 11 to 13 and sample No. Nos. 27 to 29 are sample Nos. Having other ranges. 8 to 10 and sample No. Two
It can be seen that the wear amount of the pressing member 6 and the driving force transmission member 14 can be made smaller than those of Nos. 4 to 26.

As a result, in order to further suppress the amount of wear of the pressing member 6 and the driving force transmitting member 14, the content of titanium carbide in the alumina sintered body is set to 10 to 50% by weight, and the alumina sintered body is sintered. It is understood that the maximum grain size of alumina crystals and titanium carbide crystals in the aggregate should be 4 μm or less, and the maximum pore size of the alumina sintered body should be 2 μm or less.

Further, in the sample No. 7 containing 7% by weight or more of the auxiliary component composed of paramagnetic metal oxide. 6-13,
18, 20, 22 to 29, the maximum magnetic flux density of the pressing member 6 exceeded 0.05 μT.

As a result, it is understood that the content of the auxiliary component composed of paramagnetic metal oxide is preferably 7% by weight or less.

[0051]

As described above, according to the present invention, in the ultrasonic motor comprising the vibrating body and the pressing member for transmitting the vibration of the vibrating body to the movable body side, the pressing member is mainly composed of alumina. By using an alumina sintered body containing titanium carbide as an accessory component, it is possible to reduce wear and shedding of the pressing member due to frictional driving with the movable body, and to stabilize the contact state with the movable body. Can be made. Moreover, because of the chemo-mechanical reaction during friction drive, a titanium oxide film having a larger friction coefficient than alumina or titanium carbide can be generated on the contact surface of the pressing member made of an alumina-based sintered body. Even if driven at a high speed, slippage is unlikely to occur between the pressing member and the movable body, so that the stage can be moved at a high speed.

By setting the content of titanium carbide in the alumina sintered body to 10 to 50% by weight, the wear resistance of the pressing member can be greatly improved and the frictional drive with the movable body can be achieved. The wear resistance of the pressing member can be maintained for a long time.

Further, by setting the maximum grain size of each of the alumina crystal and the titanium carbide crystal of the alumina-based sintered body to 4 μm or less and the maximum pore diameter of the alumina-based sintered body to 2 μm or less, friction driving with the movable body is performed. It is possible to further reduce wear and shedding of the pressing member due to, and to stabilize the contact state with the movable body.

Further, the content of the paramagnetic metal oxide contained as an auxiliary component in the above alumina sintered body is set to 0.05.
By setting the content to ˜7% by weight, the maximum magnetic flux density of the alumina-based sintered body can be set to 0.05 μT or less, which can be used in applications where magnetism is disliked, and the hardness of the alumina-based sintered body can be Vickers hardness. Since it is possible to maintain a high hardness of 19 GPa or more at (H _v ), it is possible to maintain the wear resistance of the pressing member even when friction driving with the driving force transmission member is performed for a long time.

Further, by using the ultrasonic motor of the present invention in the guide device using the movable body as a drive source, wear on the movable body side can be reduced, and not only the life of the ultrasonic motor but also
Since the life of the guide device can be improved and the contact state with the movable body side can be stabilized, the accuracy and the positioning accuracy of the movable body during driving can be improved. Moreover, since an appropriate frictional force with the movable body can be obtained, by driving the ultrasonic motor at high speed, the driving force of the ultrasonic motor can be efficiently transmitted to the movable body without causing slippage and driven at high speed. be able to.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an ultrasonic motor according to the present invention,
(A) is the front view, (b) is the back view.

FIG. 2 is a partially cutaway plan view showing an example of a guide device using the ultrasonic motor of the present invention as a drive source for a movable body.

FIG. 3 is a diagram showing an example of a conventional ultrasonic motor, (a)
Is a front view thereof, and (b) is a rear view thereof.

FIG. 4 is a plan view showing an example of a guide device using a conventional ultrasonic motor as a drive source of a movable body.

[Explanation of symbols]

1, 31: Ultrasonic motor 2, 32: Piezoelectric ceramic bodies 3a, 3b, 3c, 3d, 33a, 33b, 33c, 3
3d: electrode film 4,34: electrode film 5,35: vibrating body 6,36: pressing member 11: base board 12: guide member 13: stage
14: Driving force transmitting member 15: Linear scale 16: Measuring head 17: Position detecting means 18: Control unit 19: Driver 20: Case 21: Spring 22:
Spring 23: load cell

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 35/10 E

Claims (5)

[Claims] 1. An ultrasonic motor comprising a vibrating body and a pressing member for transmitting the vibration of the vibrating body to a movable body side, wherein the pressing member comprises alumina as a main component and titanium carbide as a sub-component. An ultrasonic motor characterized by being formed of a high quality sintered body. 2. The ultrasonic motor according to claim 1, wherein the content of titanium carbide in the alumina sintered body is 10 to 50% by weight. 3. The maximum grain size of alumina crystals and titanium carbide crystals in the alumina sintered body is 4 μm or less, and the maximum pore diameter in the alumina sintered body is 2 μm.
It is the following, The ultrasonic motor of Claim 1 or Claim 2 characterized by the following. 4. The alumina sintered body contains a paramagnetic metal oxide as an auxiliary component in a range of 0.05 to 7% by weight, and the maximum magnetic flux density of the alumina sintered body is 0. .0
The ultrasonic motor according to any one of claims 1 to 3, wherein the ultrasonic motor has a value of 5 µT or less. 5. The pressing member of the ultrasonic motor according to any one of claims 1 to 4 is arranged in contact with a movable body, and the vibration of the ultrasonic motor is transmitted through the pressing member. A guide device using an ultrasonic motor as a drive source for the movable body, wherein the movable body is frictionally driven.