JPH0465637B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field/Object of the Invention] The present invention relates to the improvement of piezoelectric rotating machines, and in particular to the "woodpecker type", which has the simplest structure and is said to have the highest performance among piezoelectric rotating machines. The purpose of the present invention is to provide an excellent piezoelectric rotating machine that eliminates both of the two drawbacks of the "Motor", namely, the wear of the woodpecker teeth and the inability to change the direction of rotation.

[Background technology]

A "woodpecker type" motor is a motor in which a plate-shaped head is inserted into a longitudinal mode ultrasonic transducer, such as a Languevin transducer, and is crimped in a direction inclined to the normal to the sliding surface of the rotor. This causes the rotor to hit the rotor diagonally while vibrating, which generates a large rotational torque in the rotor, making it a motor that is characterized by low speed and large torque. Multiple plate heads are usually used,
It hits the sliding surface like teeth, so it causes a lot of wear.

The present invention has previously filed several applications for a "spiral mode driven piezoelectric motor" and related technologies, eliminating the mechanism in which the sliding surface is hit by teeth, and providing a sliding mechanism with less wear using a torsion connector. However, even then, the direction of rotation of the rotor cannot be easily and instantaneously reversed using an electrical signal, which limits the applications of this type of piezoelectric rotating machine.

[Summary of the invention]

This invention solves the above-mentioned drawbacks of the prior art.In a piezoelectric rotating machine consisting of a torsion coupler, a rotor, and two longitudinal mode piezoelectric vibrators that drive them, one of the longitudinal mode piezoelectric vibrators is As a result, the sliding surface of the rotor excited by the other longitudinal mode piezoelectric vibrator is periodically pressed against the sliding surface of the torsional vibrator, which is excited and performing torsional vibration. Rotational torque is generated in the rotor,
Not only does it rotate smoothly, but by reversing the phase of the crimp vibration of the rotor that periodically crimp,
This objective was achieved by using a piezoelectric rotating machine whose rotor instantly rotates in reverse. Embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

FIG. 1 is an explanatory view showing an example of a longitudinal mode piezoelectric vibrator used in the present invention, which is a type of bolted lunge type vibrator commonly used in ultrasonic processing machines and the like. A doughnut-shaped piezoelectric ceramic vibrator with an outer diameter of 35 mm, an inner diameter of 15 mm, and a thickness of 2 mm polarized in the thickness direction (here, a Pb(ZrTi)O ₃ -based high _Q height d ₃₃
(using materials), the direction of polarization is alternately reversed, and in between
A 0.2 mm thick bronze plate ₁₁ having the same donut shape is inserted as an electrode plate, and these four plates are stacked to form the laminated vibrator 1. This was sandwiched between an aluminum vibrator 2 with a diameter of 35 mm and a thickness of 20 mm and an aluminum vibrator 3 with a diameter of 35 mm and a thickness of 10 mm, and these were tightened with aluminum bolts 4. Aluminum rod 4 is 15mm from transducer 2 and 30mm from transducer 3.
It has a protruding structure, with the protruding part having a diameter of 8 mm and an 8 mm screw 6 cut at the tip.

After fitting the ball bearing 6 into the bolt 4, an aluminum sliding plate 5 having a diameter of 35 mm and a thickness of 5 mm was screwed onto the screw (see Fig. 2). The sliding surface of the sliding plate 5 is lined with hard rubber. A ball bearing 7 was attached to the bolt 4 protruding from the side opposite to the sliding plate 5, and a nut 8 was tightened from the outside thereof. The rotor thus completed was placed in a case, and the bearings 6 and 7 were fixedly supported.

On the other hand, the stator consists of a torsional oscillator as shown in Figure 3, consisting of a laminated piezoelectric ceramic oscillator 11, the same as the rotor, an aluminum oscillator 12 with a diameter of 35 mm and a thickness of 20 mm, and an aluminum oscillator 12 with a diameter of 35 mm and a length of 40 mm. It was sandwiched together with a torsion connector 13 and tightened with an aluminum bolt 14. A hole with a diameter of 17 mm and a depth of 5 mm was bored in the head of the torsion coupler, the head of the bolt 14 was inserted into the hole, a thrust bearing was set, and the torsion coupler was tightened through the bearing. The torsion connector 13 has a head portion 13 1 with a diameter of 35 mm and a thickness of 10 mm, and a head portion 13 ₁ with a diameter of 35 mm.
It consists of a base part 13 ₂ with a thickness of 10 mm, and both are 20 mm thick.
2 mm thick plates 9 to be supported at intervals of
A beam section ₁₃₃ having beams arranged radially is fixed. This three-piece torsional connector 13 has a structure in which _{a head portion 13 1 and} a base portion 13 ₂ , which are bilaterally symmetrical with respect to a beam portion 13 3, are twisted about 10° around their central axis. , the beam plate is inclined obliquely to the central axis.

The coupled vibrator has a function of converting the expansion and contraction movement of the head portion 13 ₁ relative to the base portion 13 ₂ into a twisting movement. Therefore, when a high-frequency voltage is applied to the completed torsional vibrator to excite the resonance state, severe torsional vibration occurs. The aluminum bolt 14 protrudes about 10 mm from the end face of the torsional vibrator opposite to the head 13 ₁ , and has an 8 mm thread cut at the tip. When this screw part is screwed to the case,
The head of the torsional vibrator and the sliding surface of the rotor are
They face each other almost in contact (see Figure 4).

In a piezoelectric rotating machine in which both are housed in a case, the torsional vibrator acts as a stator and generates torsional torque, and the rotor is periodically compressed to rotate smoothly. There is a contact 1 in the case of the piezoelectric rotating machine.
5 and 16 are arranged, and electric power is supplied from the contacts 15 and 16 using the electrode plate 1 ₁ of the rotating rotor vibrator as a commutator. Since the torsional vibrator of the stator does not rotate, the power to the piezoelectric vibrator is supplied by the lead wires 17 and 18 soldered to the electrode plate ₁₁₁ .
supplied through.

The resonant frequency of the rotor and stator oscillators is
They have been prepared to match as closely as possible. Here it was 24.51kHz and was driven by a 30W oscillator outputting 40 volts at this frequency. It was connected to the stator side through a phase shifter 20 and a reversing switch 19, and when the phase was adjusted, it rotated smoothly. When the polarity of the applied voltage was reversed by the reversing switch 19, the rotor rotated in the opposite direction. The piezoelectric rotating machine of the present invention generates a large rotational torque at a constant low speed of around 300 rpm, so it can generate large rotational torque at a low speed that could not be achieved with a normal electric motor without using a reduction gear. The feature is that it is possible to obtain output.

In the above embodiment, the material of the vibrator is aluminum, which is 5056 aluminum alloy, which is properly called high-strength aluminum.
A similar effect can be obtained by using a spring material such as a copper alloy such as phosphor bronze. This also applies to the material of the sliding surface, such as rubber,
In addition to a hard wear-resistant material such as a polymeric material, a plane metal or the like may be used.

In the above-mentioned embodiment, a piezoelectric rotating machine having a structure consisting of a rotor that combines a rotor and longitudinal vibration, and a stator that combines a torsion coupler and a longitudinal vibrator was illustrated, but it is also possible to integrate the rotor and longitudinal vibrator. Instead, it is also possible to adopt a structure in which only the rotor rotates, and the longitudinal vibrator only generates vibration but does not rotate.
Similarly, in the case of a torsional vibrator, torsional vibration may be generated by crimping the longitudinal vibrator and torsional coupler, which only perform longitudinal vibration, without bolting the torsional coupler and the longitudinal vibrator together. .

The driving frequency is selected from the resonant frequency of the vibrator, so
In general, large devices have low frequencies, while small devices have high frequencies exceeding 50kHz. Furthermore, the structure in which the bolt protrudes from the vibrator is an amplitude increasing structure, and the longer the bolt is made to be an odd multiple of 1/4 of the wavelength and the thinner the cross section is, the more the amplitude is expanded.

〔Effect of the invention〕

As explained above, in a piezoelectric rotating machine consisting of a torsion coupler, a rotor, and two longitudinal mode piezoelectric vibrators that drive them, torsional vibration is performed by being excited by one of the longitudinal mode piezoelectric vibrators. The sliding surface of the rotor, which is excited by the other longitudinal mode piezoelectric vibrator, is periodically pressed against the sliding surface of the torsional vibrator, which is attached to the rotor. In addition to rotating, the rotor periodically rotates in reverse by reversing the phase of the crimp vibration of the rotor, which causes the rotor to instantly reverse rotation, which reduces friction even though the rotational torque is large. There is little wear on the sliding surfaces that come in contact with the rotor, which instantly starts rotating at a constant speed in response to an electrical signal.When the electrical signal is stopped, the rotation stops instantly, and while the rotor is stopped, the rotor is pressed against the stator, reducing friction. Another feature is that it has a large holding force to prevent it from moving easily due to its high resistance. In addition to these features, although the structure is simple and manufacturing is easy, it has high electromechanical conversion efficiency and long life and high reliability.The greatest feature of the present invention is high efficiency. It is based on the ``woodpecker-type'' piezoelectric motor, and is also capable of reverse rotation. The torsional coupler of the present invention is a coupler that converts longitudinal vibration into torsional or sliding vibration, and utilizes the bending vibration of a beam, and the same effect can be obtained even if a buckling spring that is curved and deformed is used for the beam. can get.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a vertical vibrator constituting the piezoelectric rotating machine of the present invention, and FIG. 2 is a perspective view showing an embodiment of a rotor incorporating the vertical vibrator shown in FIG. , FIG. 3 is a perspective view showing an embodiment of a stator comprising a torsional vibrator constituting the piezoelectric rotating machine of the present invention, and FIG. 4 is an explanatory diagram showing an embodiment of the piezoelectric rotating machine of the present invention. 1, 11...Laminated vibrator, 1 ₀ ...Piezoelectric plate, 1
₁ , 11 ₁ ... Electrode plate, 2, 3, 12 ... Vibrator,
4, 14... Bolt, 5... Sliding plate, 13... Torsion connector, 19... Polarity reversal switch.

Claims (1)

[Claims] 1. In a piezoelectric rotating machine consisting of a torsion coupler, a rotor, and two longitudinal mode piezoelectric vibrators that drive them, torsional vibration is excited by one longitudinal mode piezoelectric vibrator. The sliding surface of the rotor excited by the other longitudinal mode piezoelectric vibrator is periodically pressed against the sliding surface of the torsional vibrator that is moving, and the sliding surface of the rotor that is being periodically pressed is A piezoelectric rotating machine characterized by being configured so that a rotor can rotate in the opposite direction by reversing the phase of crimping vibration. 2. In the piezoelectric rotating machine according to claim 1, the vertical mode piezoelectric vibrator has a structure in which the tip of the bolt is selected to have a length that becomes the antinode of vibration, and protrudes toward one side of the vibrator. A piezoelectric rotating machine characterized by expanding the amplitude. 3. A piezoelectric rotating machine characterized in that the material of the bolt described in claim 2 is the same as that of the vibrator.