JPH04131189U - Ultrasonic motor drive power supply device - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to eliminate drive abnormalities or inability to drive due to capacitance of connection shield wires when the connection distance between an ultrasonic motor and its drive power supply is long. [Configuration] Two output transformers 4, 4' of the drive power supply device
Coils 5 and 5' are connected in parallel to each of the secondary sides of
The inductance of the coils 5 and 5' is set to a value that causes parallel resonance at the drive output frequency with the capacitance 6 and 6' of the shield wire to be connected between the ultrasonic motor and the ultrasonic motor. do.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a driving power supply device for an ultrasonic motor.

0002

[Conventional technology]

Ultrasonic motors are one of the most popular actuators due to their high torque and high rotational accuracy. It is widely used as one. The ultrasonic motor is used as a driving device for this ultrasonic motor. In order to generate traveling waves in the piezoelectric ceramic bonded to the ring-shaped vibrating body of the A power supply device that outputs two drive voltages with a 90° phase difference and a frequency of several tens of kHz. used.

0003 Piezoelectric ceramics are driven by applied voltage, so the drive power supply has an output voltage. The secondary side (output side) inductance of the output transformer is is the input capacitance of the piezoelectric ceramic of the ultrasonic motor near the frequency of the driving voltage ( (braking capacity) is set to a value that resonates in parallel with the braking capacity. As mentioned above, the ultrasonic motor is a high impedance voltage drive type, so the drive voltage is The connection wire to the source device cannot be too long, and electrostatically shielded wire must be used. There must be. Usually a shielded wire with a length of about 20 cm or less is used. .

0004

[Problem that the idea aims to solve]

However, as the performance of ultrasonic motors has improved and they have become smaller, the types of equipment that can be used have expanded. There is a demand to enlarge the ultrasonic motor and drive it from a distance away from the attachment part. It has increased. For example, if the installation interval between the ultrasonic motor and the drive power supply is several tens of meters, A coincidence occurred. When connected with this length of shielded wire, approximately 100 pF capacitance reduces the input capacitance of the ultrasonic motor and the output of the power supply. Resonant frequency of the parallel resonant circuit formed with the secondary inductance of the transformer Shifts to the lower side, the impedance at the frequency of the drive voltage decreases significantly. The drive voltage may drop and the ultrasonic motor may not operate normally, making abnormal noises or stopping. Sometimes it may stop. Furthermore, as the current increases, the output transformer generates heat, causing heat to the surrounding area. This can lead to problems such as increased temperature.

[0005] In such a case, the inductance on the secondary side of the output transformer should be The capacitance of the long shielded wire and the input capacitance of the ultrasonic motor are balanced at a given frequency. Although it is possible to set the column to resonate, the length and standard of the connecting shield wire may change. It is not practical in terms of construction time and cost to design and manufacture an output transformer each time It is difficult to administer. In addition, we also provide various output tracks corresponding to various standards and lengths of shielded wires. There are problems with producing and stocking products such as incurring economic losses. . The purpose of this invention is to improve such defects and improve the connection between the ultrasonic motor and the drive power supply. A drive power supply device that allows the ultrasonic motor to operate normally even over long distances. It is about providing.

[0006]

[Means to solve the problem]

The ultrasonic motor drive power supply device of the present invention uses the oscillation output of an oscillator of a predetermined frequency. The oscillation output and the output obtained through the 90° phase shifter are each amplified to generate an output transformer. An ultrasonic motor that obtains two drive outputs to drive the ultrasonic motor from the secondary side of the In the motor drive power supply device, Connect each of the secondary side output terminals of the two output transformers in parallel with the secondary side winding. static electricity of the shielded wire to be connected between the ultrasonic motor and the ultrasonic motor. Adjust the inductance value that causes parallel resonance at the drive output frequency using the capacitance. It is characterized by having a coil that can be set to a knot.

[0007]

【Example】

The present invention will be explained in detail below with reference to the drawings. 1 to 4 are circuit diagrams showing embodiments of the present invention. In these figures , 1 is an oscillator, and the frequency of the drive output is set. Usually several tens of kHz In the experiment, the frequency was set to about 40kHz. 2 is a 90° phase shifter. 3,3' is electric power Amplifying transistors 4 and 4' are output transformers thereof. This output transformer The inductance on the output side of 4 and 4' is the input capacitance of the ultrasonic motor 8 to be driven. It is set to a value that resonates in parallel near the frequency of the drive voltage and drive voltage. 7 is the ultrasonic mode 6 and 6' are the shielded wires to which the conductor 8 is connected, and 6 and 6' are the static Indicates capacitance. 5 and 5' are coils added according to the present invention, and are connected to the output transformers 4 and 4'. Connected in parallel with the output terminal. In the first embodiment of FIG. 1, 5, 5' are coils with fixed inductance values. The standard and length of the shielded wire 7 are constant, and the capacitance 6, 6' varies. It is effective when it can be ignored. This is because the coil structure is simple and economical. It is true. The inductance value of this coil 5 is equal to the capacitance 6 of the shield wire 7 and The inductance value of the coil 5' and the capacitance 6' of the shield wire 7 are respectively driven. They are set to resonate in parallel near the voltage frequency.

[0008] In the second embodiment of FIG. 2, the capacitances 6, 6' of the shield wire 7 are This is effective when there are variations depending on the sheath specifications. In other words, the coils 5 and 5' are inducted. Setting the frequency of parallel resonance to a predetermined value by creating a structure in which the ductance can be varied. be able to.

[0009] In the third embodiment shown in FIG. 3, the types of lengths of the shield wires 7 are standardized in advance and their static This is effective when several values of capacitance 6, 6' are determined. coil 5, By providing a tap corresponding to the type of shield wire 7 on 5', a specified input can be achieved. ductance can be obtained.

0010 In the fourth embodiment shown in FIG. 4, the length of the shield wire 7 is different and the capacitance 6,6 This is effective when the range of values of ′ is wide. Variable inductance of coils 5 and 5' The variable range of inductance is increased by having a structure that allows for is wide.

[0011]

[Effect of the idea]

As explained in detail above, by implementing the present invention, it is possible to Drives ultrasonic motors in the best possible condition, from short to long connection distances can do. Furthermore, if you prepare one type of output transformer for the power supply device, you can easily adjust the length and specifications of the shield wire. It can be applied to a wide range of different grades, so it can be used for a wide variety of applied equipment. We can mass-produce products in advance and stock finished products to meet requests for short delivery times. The practical effects are extremely large.

[Brief explanation of drawings]

[Fig. 1] A circuit diagram showing a first embodiment of the present invention.

[Fig. 2] A circuit diagram showing a second embodiment of the present invention.

[Fig. 3] Circuit diagram showing a third embodiment of the present invention

[Fig. 4] A circuit diagram showing a fourth embodiment of the present invention.

[Explanation of symbols]

1 Oscillator 2 90° phase shifter 3,3' transistor 4,4' Output transformer 5,5' coil 6,6' Capacitance of shielded wire 7 Shield wire 8 Ultrasonic motor

Claims (1)

[Scope of utility model registration request] Claim 1: A system for driving an ultrasonic motor from the secondary side of an output transformer by amplifying the oscillation output of an oscillator of a predetermined frequency and the output obtained by passing the oscillation output through a 90° phase shifter. In a drive power supply device for an ultrasonic motor that obtains two drive outputs, a wire is connected to each of the secondary output terminals of the two output transformers in parallel with the secondary winding, and between the ultrasonic motor and the secondary winding. 1. A drive power supply device for an ultrasonic motor, comprising a coil capable of adjusting and setting an inductance value such that parallel resonance occurs at the drive output frequency due to the capacitance of a shielded wire to be connected to the coil.