CN101071999B - Motion superimposed linear ultrasonic motor and electric excitation method - Google Patents

Abstract

The invention relates to a motion superimposed linear ultrasonic motor and an electric excitation mode, belonging to the ultrasonic motor. The motor includes: a stator and a mover. The stator is an annular elastic body (2), and the upper and lower ends of the outer surface of the elastic body have uniformly distributed driving teeth, and the upper and lower ends of the inner surface are respectively bonded with piezoelectric ceramic sheets (10). The mover includes a lower slider (3), an upper slider (7) and an upper slider (6); the spring force provided by the compression spring (9) will move the upper slider and the fixed lower slider (1) Press them on the driving tooth surfaces on both sides of the stator respectively. The upper and lower layers of piezoelectric ceramics respectively excite the two vibration modes of the stator to superimpose to form traveling waves on the surface of the stator, so that the particles on the driving end surface generate elliptical motion to push the mover to move continuously in a straight line. The movement of the upper slider, as the output movement of the motor, is the superposition of the relative movement of the upper slider relative to the stator and the self-motion of the stator. The linear ultrasonic motor can output linear motion with high torque, high speed and high efficiency.

Description

Motion superimposed linear ultrasonic motor and electric excitation method

Technical field:

The motion superimposed linear ultrasonic motor and electric excitation method of the invention belong to the field of ultrasonic motors.

Background technique:

Ultrasonic motor is a new type of power output device that utilizes the inverse piezoelectric effect of piezoelectric ceramics and ultrasonic vibration. Linear ultrasonic motors are a major category of ultrasonic motors. Among them, the traveling-wave linear ultrasonic motor is a kind of linear ultrasonic motor. At present, the traveling wave linear ultrasonic motor adopts a straight beam or ring beam structure. The ring beam traveling wave linear ultrasonic motor uses piezoelectric ceramics bonded to the beam to excite the traveling wave on the surface of the ring beam to drive the moving wave pressed on the beam. The mover moves in a straight line. The straight-beam traveling-wave linear ultrasonic motor uses the oscillators at both ends of the straight beam to excite and absorb vibration respectively to form traveling waves on the surface of the beam to drive the movement of the slider. The beams on the traveling-wave linear ultrasonic motors of these two structures are relatively large. When the motor drives the mover, the entire beam must vibrate, resulting in high power consumption and low efficiency. Single-sided driving has low speed and small torque.

Invention content:

The purpose of the present invention is to develop a motion superimposed linear ultrasonic motor with small size, simple structure, large torque, fast speed, high efficiency and fast response.

The motion superimposed linear ultrasonic motor of the present invention includes a stator, a mover and piezoelectric ceramics. Its characteristics are: the stator includes an annular elastic body and a piezoelectric ceramic sheet, the upper and lower outer surfaces of the annular elastic body have uniformly distributed driving teeth, and the upper and lower sides of the elastic body are respectively bonded with piezoelectric ceramics for exciting the elastic body. Vibrate. The mover is composed of two sliders; the slider is pressed against the drive tooth surface of the stator by the spring force of the compression spring; the upper and lower piezoelectric ceramics are simultaneously excited by the same frequency sinusoidal signal with a phase difference of π/2 to respectively excite the stator's Two vibration modes, the superposition of these two vibration modes forms a traveling wave on the surface of the stator, so that each particle on the driving end surface generates an elliptical motion to push the mover to move continuously in a straight line. Wherein, the lower slide is fixed, and the lower drive end face of the stator drives itself to make a self-propelled linear motion; meanwhile, the upper drive end face of the stator drives the upper slide bar to make a linear motion in the same direction. The output motion of the slider on the motor is the superposition of these two motions. When the excitation signals are opposite, the reverse linear motion of the mover can be realized.

The linear ultrasonic motor has the advantages of simple structure, small size, large output torque, high speed and high efficiency.

Description of drawings:

Figure 1 is a schematic diagram of the structure of a motion superimposed linear ultrasonic motor. Label name in the figure: 1. Lower slider; 2. Elastic body; 3. Lower slider; 4. Bolt; 5. Pulley 6. Upper slider; 7. Upper slider; 8. Nut; 9. Compression spring; 10 . Piezoelectric ceramic sheet; 11. Middle block.

Fig. 2 is a schematic diagram of the traveling wave formation of the motion superimposed linear ultrasonic motor. Among them, Figure 2(a) is the bending mode (1) of the elastic body; Figure 2(b) is the bending mode (2) of the elastic body. The two bending modes shown in Figure 2 are π/2 out of phase in space.

Fig. 3 is a schematic diagram of the polarization partition of the piezoelectric ceramic sheet, wherein Fig. 3 (a) is a schematic diagram of the polarization of the piezoelectric ceramic sheet on the upper layer of the stator;

Figure 3(b) is a schematic diagram of the polarization partition of the piezoelectric ceramic sheet under the stator.

Figure 4 is a schematic diagram of the motion trajectory of the surface of the stator driven teeth, in which Figure 4(a) is a schematic diagram of the clockwise movement of the surface particles of the stator driven teeth; Figure 4(b) is a schematic diagram of the leftward movement of the motor output; Figure 4(c) is a schematic diagram of the stator driven Schematic diagram of counterclockwise movement of tooth surface particles; Figure 4(d) is a schematic diagram of motor output moving to the right.

Detailed ways:

A motion superimposed linear ultrasonic motor is shown in Figure 1. Its features: the stator is an annular elastic body 2 with evenly distributed driving teeth, and the upper and lower sides of the elastic body are bonded with piezoelectric ceramic sheets 10, which are used to respectively excite the two bending modes of the elastic body. The mover is composed of the lower slider 3 and the upper slider 6; the lower slider uses the middle block 11 and the bolt 4 to keep its position fixed with the elastic body and the upper slider, and the spring force of the compression spring 9 makes the belt driving teeth of the elastic body The two driving surfaces of the stator are respectively pressed on the movable upper slider and the fixed lower slider; the two vibration modes of the stator are respectively excited by the upper and lower piezoelectric ceramic sheets, and the superposition of these two vibration modes forms a The traveling wave on the surface of the elastic body makes the particles on the lower driving end surface produce elliptical motion to push the elastic body to make a linear motion, and the elastic body drives the upper and lower sliders to move together; at the same time, the elliptical motion of each particle on the upper driving end surface of the elastic body also pushes the upper slider. Make a linear motion in the same direction to form a linear ultrasonic motor. Movement in the opposite direction is achieved by exciting the elastic vibration modes with opposite drive signals. The motor is driven by traveling waves on two driving surfaces to realize the superimposition of up and down motions, with fast speed and high efficiency.

Structural design principles: 1. The two vibration modes of the elastic body are excited by the inverse piezoelectric effect of the piezoelectric ceramic sheet, and the structural size of the elastic body should be adjusted so that the two vibration frequencies are consistent and the spatial phase difference is π/2.2 , Use two sinusoidal signals of the same frequency with a phase difference of π/2 to excite the upper and lower layers of piezoelectric ceramics respectively, and the two vibration modes of the excited elastic body are synthesized into traveling waves on the upper and lower end surfaces of the elastic body, which form The elliptical trajectory drives the mover to move in a straight line.

The following is an example of a motion superimposed linear ultrasonic motor:

Two vibration modes of the stator are excited by using the inverse piezoelectric effect d31 of the piezoelectric ceramic sheet. Figure 1 is a schematic diagram of the structure of the motor, which is mainly composed of a stator and a mover. The stator is a ring-shaped metal elastic body. The left and right ends are semicircular arc-shaped respectively, and the upper and lower ends are linear. To amplify the amplitude of the driving tooth surface. Two layers of piezoelectric ceramic sheets are bonded to the upper and lower surfaces of the elastic body, which are respectively used to excite the two vibration modes of the stator. The whole stator size is 36mm×18mm×8mm.

The motion trajectory analysis of the motor stator drive surface is shown in Figure 4:

The upper and lower piezoelectric ceramic sheets of the stator are partitioned as shown in Figure 3(a) and (b). The arrow direction of the piezoelectric ceramic sheet indicates the polarization direction. Among them, the upper piezoelectric ceramic sheet is divided into three partitions, and its length ratio is 3:4:3, which is used to excite the vibration mode (1) of the stator (see Figure 2 (a)); the lower piezoelectric ceramic sheet is divided into two partitions , whose lengths are equal, are used to excite the stator in vibration mode (b) (see Fig. 2(b)). Provide the sinusoidal excitation signal E=Usinωt to the three surfaces 11, 12 and 13 of the upper piezoelectric ceramic sheet, and provide the cosine excitation signal E=Ucosωt to the two surfaces 21 and 22 of the lower piezoelectric ceramic sheet to simultaneously excite the two sides of the stator. Two vibration modes with the same frequency and phase difference of π/2, these two modes synthesize the traveling wave of the stator in the clockwise direction. The motion of the tooth surface particles driven by the stator up and down is an elliptical motion 1 in the clockwise direction (see Figure 4(a)). As shown in Figure 4(b), the lower drive tooth surface of the stator drives the stator itself to make a rightward linear motion 2, and at the same time, the upper drive tooth surface of the stator drives the upper slider to make a rightward linear movement relative to the stator 3, the absolute movement of the upper slider It is the superposition of two rightward movements; the cosine excitation signal E=Ucos ωt is provided to the three surfaces 11, 12 and 13 of the upper piezoelectric ceramic sheet, and the sinusoidal excitation signal E=Usin ωt is provided to the lower piezoelectric ceramic sheet The two surfaces 21 and 22 of the stator simultaneously excite two vibration modes of the same frequency and phase difference of π/2 of the stator, and these two modes synthesize the traveling wave of the stator in the counterclockwise direction. The motion of the tooth surface particles driven by the stator up and down is an elliptical motion 1 in the counterclockwise direction (see Figure 4(c)). As shown in Figure 4(d), the lower drive tooth surface of the stator drives the stator to make a leftward linear motion 2, and at the same time, the upper drive tooth surface of the stator drives the upper slider to make a leftward linear movement 3 relative to the stator, and the absolute movement of the upper slider is is the superposition of two leftward movements.

Claims (2)

1. motion superposition linear ultrasonic motor, comprise stator, mover and piezoelectric ceramic piece, it is characterized in that, described stator comprises annular elastomeric (2), piezoelectric ceramic piece (10), wherein two lateral surfaces up and down of annular elastomeric (2) have equally distributed driving gear, two piezoelectric ceramic pieces (10) are bonded in annular elastomeric (2) inner chamber respectively up and down on two inner surfaces, described mover comprises that the inboard wears two slide blocks (7 up and down of pulley, 3) and movable last draw runner (6), fixing following draw runner (1), wherein movable last draw runner (6) medial surface is pressed on the driving gear of annular elastomeric (2) superolateral surface, fixing following draw runner (1) medial surface is pressed on the driving gear of annular elastomeric (2) inferolateral surface, top shoe (7) is placed on movable last draw runner (6) lateral surface by the pulley of medial surface, sliding block (3) contacts with the lateral surface of the following draw runner of fixing (1) by the pulley of medial surface, utilize the spring force that bolt (4) provides through the interstitial hole of stator and mover and by the compression spring (9) that is sleeved on bolt (4) upper end and place intermediate mass (11) in the middle of annular elastomeric (2) inner chamber, stator is connected formation motion superposition linear ultrasonic motor in aggregates with mover.

2. the electric excitation mode of a motion superposition linear ultrasonic motor as claimed in claim 1, it is characterized in that, the sinusoidal signal that is pi/2 with two phase differences encourages two mode of oscillations with frequency phase difference pi/2 of stator can make stator produce the row ripple simultaneously, makes stator drive flank of tooth generation elliptic motion up and down and promotes the continuous rectilinear motion of mover.

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