JP2903615B2 - Linear ultrasonic motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a linear ultrasonic motor driven by a traveling wave.

[Conventional technology]

A conventional linear type ultrasonic motor using a surface wave is reported in "Automation Technology," Vol. 15, No. 12, in a special issue entitled "Approach to Ultrasonic Motor Development." In this method, one linear portion of a land track type resonator is brought into contact with a mover to fix the resonator and generate a response speed or relative displacement between the resonator and the mover.

[Problems to be solved by the invention]

The conventional linear ultrasonic motor transmits a traveling wave orbiting a land track type resonator only to a movable element that is in contact with one linear portion of energy, and transmits a traveling wave of the other linear portion. There is a problem that the transmission is wasted and the efficiency of the motor is low.

The present invention provides an efficient linear type ultrasonic motor utilizing the energy of traveling waves of two linear portions.

[Means for solving the problem]

A linear ultrasonic motor according to the present invention is an ultrasonic motor in which a mover is brought into contact with a linear portion of a land track type resonator to generate a relative speed or a relative displacement between the resonator and the mover. A piezoelectric element that generates a traveling wave that circulates around the resonator by receiving a periodically applied voltage, and two movable elements that are symmetrically arranged around the resonator and have a length equal to or longer than the movable range of a linear portion that contacts the resonator. And the two movers move in parallel and in opposite directions to each other, one point on each of the two movers, the points P _A and P _B that are the base points for the relative speed or relative displacement between the two points. _A moving mechanism for generating a relative speed or a relative displacement between the points P _A and P _B , a synchronizing mechanism for moving the two movers in synchronization, the resonator and the two movers, Ideal for moving two movers with traveling waves generated on the resonator And a contact adjustment mechanism for contacting the contact.

〔Example〕

The principle operation of the linear ultrasonic motor according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view showing the configuration of an embodiment of a linear ultrasonic motor according to the present invention, and FIG. 2 is a side view.

The shape of the resonator 1 is a land track type including a straight portion and a curved portion. The piezoelectric element 6 is provided in a portion not in contact with the mover A2 and the mover B3. In this embodiment, the linear portion is provided on the inner side not in contact with the mover. When the voltage applied to the piezoelectric element 6 is periodically changed, a traveling wave circling the resonator 1 is generated by expansion and contraction of the piezoelectric element.

The mover A2 and the mover B3 are in contact with the respective linear portions of the resonator 1. Then, a contact adjusting roller 8 supported by the contact adjusting frame 7 adjusts the contact pressure.
When the contact pressure reaches an appropriate level, the moving elements A2 and B3 are caused to move by the traveling waves circling the resonator 1 described above.
Sliding movement is performed while contacting the linear part of.

Linear type ultrasonic motor of the present embodiment, since the movable element A2 and the movable element B3 moves, is to generate the relative velocity or relative displacement between the base point P _A and the base point P _B. However, since the operation of the linear ultrasonic motor normally uses friction, a fixed response to the command value cannot be obtained. Origin P _A and base For that reason and varies the movement of the movable element A2 and the movable element 3 is in a free state mover reciprocates once
P _B does not return to its original state. Therefore, in this embodiment, the mover
A synchronizing mechanism is provided so that A2 and the mover B3 move in parallel and in opposite directions at regular intervals. In this embodiment, a rack is provided on the mover A2 and the mover B3, and the synchronization mechanism pinion 9 supported by the synchronization mechanism pinion support 10 integrated with the touch adjustment frame 7 is combined with the rack of the mover A2 and the mover B3. Combination and synchronization mechanism.

As described above, the linear ultrasonic motor according to the present invention can be realized with the configuration shown in FIGS.

Next, the driving principle of the mover 11 will be described in detail with reference to FIGS. Here, mover 11 is mover A2
Alternatively, the mover B3 is shown.

FIG. 3 is a graph showing the relationship between the applied voltage and the amount of elastic deformation when a voltage is repeatedly applied to the piezoelectric element 6. FIG. 4 is an elastic wave propagation principle diagram showing a state in which an elastic wave propagates through the land track type resonator 3. FIG. 5 is a principle diagram of the mover drive showing how the mover 11 moves by the traveling wave of the resonator 3.

As shown in the time-applied voltage relationship curve of FIG.
When a voltage is repeatedly applied to the piezoelectric element, there is a slight delay in the hysteresis characteristic of the piezoelectric element, but the deformation is repeated almost like a time-elastic deformation relation curve.

Then, the phase is shifted to the piezoelectric elements 6a to 6e arranged as shown in FIG. 4 and FIG. In the figure, the piezoelectric element is arranged only on one linear part, but the piezoelectric element is arranged on the other linear part in the same manner, and the voltage is repeatedly applied synchronously. When the piezoelectric elements 6a to 6e in FIG. 4 are in the states A to E in FIG. 3, respectively, the resonator 1 is deformed like the resonator board surface 12 in FIG. When the time advances in this state, the state becomes like the resonator board surface 13 after T / 4 time in FIG. If the voltage is repeatedly applied, the traveling wave 14 shown in FIG. Then, the point of the mover 11 shown in FIG.
1 moves in the direction of the traveling wave 14.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, two linear parts of a land track type resonator can be utilized and an efficient linear type ultrasonic motor can be provided. Further, the movable range can be increased by lengthening the mover, and further, since the ultrasonic motor is used for the holding torque, no energy is required, and for example, a driving source for controlling the attitude and vibration of a large space structure can be provided.

[Brief description of the drawings]

FIG. 1 is a front view showing the structure of an embodiment of a linear ultrasonic motor according to the present invention, FIG. 2 is a side view thereof, FIG. 3 is a diagram showing the relationship between applied voltage and elastic deformation, and FIG. FIG. 5 is a diagram of the principle of propagation, and FIG. 1 ... resonator, 2 ... mover A, 3 ... mover B, 4 ...
Reference point P _A , 5 Reference point P _B , 6 Piezoelectric element, 7 Contact adjustment frame, 8 Contact adjustment roller, 9 Synchronous mechanism pinion, 10 Synchronous mechanism pinion support, 11 Movable element, 12, 13… Resonant point board surface, 14… Traveling wave.

Claims (1)

(57) [Claims] An ultrasonic motor for generating a relative speed or a relative displacement between a resonator and a movable element by bringing the movable element into contact with a linear portion of a land track type resonator. A piezoelectric element for generating a traveling wave circling the receiving resonator, two movable elements symmetrically arranged around the resonator and having a length equal to or longer than a movable range of a linear portion in contact with the resonator; There is one on each mover,
P _A , P _B which is the base point of relative speed or relative displacement between two points
Move the point and the two movers in parallel and in opposite directions,
_A moving mechanism for generating a relative speed or a relative displacement between the points P _A and P _B , a synchronizing mechanism for moving the two movers synchronously, and the resonator and the two movers, A linear ultrasonic motor, comprising: a contact adjusting mechanism that optimally contacts two movers with a traveling wave generated above.