JPH0382379A - Miniature motor - Google Patents

Abstract

PURPOSE:To improve accuracy and resolution of a motor by driving an actuator in which pawls to be engaged with fine teeth formed uniformly on the periphery of a rotor coupled directly to a rotational shaft are secured by two piezoelectric elements perpendicular to each other. CONSTITUTION:A rotor 7 secured to a rotational shaft 9 is rotatably supported by a bearing 5. Fine teeth are formed uniformly on the periphery of the rotor 7. A piezoelectric element 2 elongated and contracted in directions X and secured at its one end to a frame 1 and a piezoelectric element 3 elongated and contracted in directions Y and secured at its one end to the frame 1 are provided. The elements 2, 3 support an actuator 4 through hinges 2a, 3a. Four actuators 4 are arranged at an interval of 90 deg. on the periphery of the rotor 7. The rotor 7 is incrementally rotated in a direction of an arrow A or B in various combinations of ON and OFF of one or both of the elements 2, 3. Thus, a motor having a small size, a light weight and high accuracy is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a minute rotary motor that transmits minute rotational motion.

[Conventional technology]

Many of the various devices used in the information processing field require precise and minute rotational movements, such as paper feed mechanisms and print head feed mechanisms in dot print printers, and magnetic heads in magnetic disk drives. access mechanisms, etc.

Conventionally, pulse motors are often used in such applications. That is, since the pulse motor does not require a complicated servo mechanism, it has the advantage that the above-mentioned device can be constructed using a relatively simple mechanism.

[Problem to be solved by the invention]

However, the resolution of such a pulse motor is structurally limited to about 1/400 per rotation of the rotor.
If a smaller rotation than this is required, there is a drawback that the speed must be changed via a gear train or the like.

Furthermore, as mentioned above, since the gear train and the like are required, the number of parts not only increases, but also has the drawback that mechanical accuracy is inevitably deteriorated due to backlash of the parts.

[Means to solve the problem]

The micro-rotary motor of the present invention includes a □-driver that is directly connected to a rotating shaft and has a uniform minute tooth profile around the periphery, an actuator that has fixed pawls that fit into the tooth profile, and a motor that is orthogonal to each other that drives the actuator. and first and second piezoelectric elements arranged.

〔Example〕

Hereinafter, a micro rotation motor according to the present invention will be explained with reference to the drawings.

FIG. 1 is a partial side view showing an embodiment of the present invention. This embodiment has four 7-chip machine mechanisms.
I will explain one of them. In the figure, the rotating shaft 6 of the micro-rotation motor is slightly rotated by operating the displacement ΔX of the X piezoelectric element 2 and the displacement ΔY of the Y piezoelectric element 3 in combination.

The frame l forms a framework that holds the mechanical configuration of the micro-rotary motor.

One end of the X piezoelectric element 2 is fixed to the frame 1, and the other end supports the actuator 4 via an X hinge 2a. Furthermore, one end of the Y piezoelectric element 3 is fixed to the frame l so that the direction of expansion and contraction of the Y piezoelectric element 3 is perpendicular to the direction of expansion and contraction of the X piezoelectric element 2, and the other end supports the actuator 4 via a Y hinge 3a. .

The actuator 4 is the above-mentioned X hinge 2a and Y hinge 3.
X piezoelectric element 2 and Y piezoelectric element 3
can move freely in expansion and contraction directions perpendicular to each other. Then, fix the claw 4a with the tip facing the direction in which the X piezoelectric element 2 expands and contracts.

The rotating shaft 6 is fitted into a bearing 5 fixed to the frame 1 and supported so as to be rotatable. A rotor 7 having teeth 7a carved around the periphery is directly connected to the rotor 7.

Furthermore, the normal direction of the rotor 7 is always the same as the claw 4a and the tooth 7a.
is in the direction of fitting.

FIGS. 2(a) and 2(b) are explanatory diagrams showing the operation of the seven rotor mechanisms when rotating the rotor 7 in the direction A in FIG. 1.

FIG. 2(a) shows the order in which the tip of the claw 4a moves.

In the figure, the coordinates of the tip of the claw 4a in the initial state (the state in which none of the piezoelectric elements are energized, that is, the applied voltage is OFF) are (0,0), and the applied voltage of the X piezoelectric element 2 is When turned ON, ΔX1Y When the voltage applied to the piezoelectric element 3 is turned ON, the tip of the claw 4a moves by ΔY. Numbers and arrows indicate the order of movement. That is, when the X piezoelectric element 2 is turned on, the tip of the claw 4a becomes (ΔX,
0) and fits into the teeth 7a of the rotor 7. Subsequently, when the Y piezoelectric element 3 is turned on, the claw 4a pushes the tooth 7a in the direction A, and its tip moves toward (ΔX, ΔY). then X
When the piezoelectric element 2 is turned off, the tip of the claw 4a is (0, ΔY)
, and disengages from the tooth 7a. Further, when the Y piezoelectric element 3 is turned off, the tip of the claw 4a returns to (0,0) and returns to the initial state. In this way, the rotating shaft 6 to which the rotor 7 is directly connected is slightly rotated in the A direction by l pitch of the teeth 7&.

FIG. 2(b) shows the relationship between the position of the tip of the claw 4a and the biasing state of each piezoelectric element 2 and 3 over time.

That is, in operation 1, the toe is located at (ΔX, 0), the X piezoelectric element 2 is ON, and the Y piezoelectric element 3 is OFF. At this time, the claw 4a and the tooth 7a are fitted together.

In operation 2, the toe is located at (ΔX, ΔY), and both the X piezoelectric element 2 and the Y piezoelectric element 3 are ON.

At this time, the claw 4a pushes the tooth 7a from (ΔX, 0) to (Δ
X, ΔY). In operation 3, the toe is located at (0, ΔY), the X piezoelectric element 2 is OFF, and the Y piezoelectric element 3 is ON. At this time, the claw 4a comes off the tooth 7a. In operation 4, the toe is located at (0,0), and both the X piezoelectric element 2 and the Y piezoelectric element 3 are OFF. In other words, it returns to its initial state.

FIGS. 3(a) and 3(b) are explanatory views showing the operation when rotating the rotor 7 in the direction B in FIG. 1.

FIG. 3(a) shows the order in which the tip of the claw 4a moves.

When the toe is initially located at (0, 0), if the Y piezoelectric element 3 is turned on, the tip of the claw 4a moves (0, ΔY). Subsequently, when the X piezoelectric element 2 is turned on, the tip of the claw 4a moves to (ΔX, ΔY) and fits into the tooth 7a. Next Y
When the piezoelectric element 3 is turned off, the claw 4a pushes the tooth 7a in the direction B, and its tip moves to (ΔX, 0). Further X
When the piezoelectric element 2 is turned off, the toe moves to (0, O) and escapes from the tooth 7a. In this way, the rotating shaft 6 to which the rotor 7 is directly connected is slightly rotated in the direction B by one pitch of the teeth 7a.

FIG. 3(b) shows the transition of the relationship between the position of the tip of the claw 4a and the biasing state of each piezoelectric element 2 and 3 in FIG. , the X piezoelectric element 2 is OFF and the Y piezoelectric element 3 is ON.

At this time, the pawl 4a faces the tooth 7a to be pushed in the direction B, but does not fit into it.

In operation 2, the toe is located at (ΔX, ΔY), and both the X piezoelectric element 2 and the Y piezoelectric element 3 are ON.

At this time, the pawl 4a fits into the tooth 7a. In operation 3, the toe is located at (ΔX, 0), and the X piezoelectric element 2 is ON and the Y piezoelectric element 3 is OFF. At this time, the claw 4a pushes the tooth 7a,
The toe moves from (ΔX, ΔY) to (ΔX, 0). In operation 4, the toe is located at (0, 0''), and the X piezoelectric element 2 and Y piezoelectric element 3 are OFF.At this time, the claw 4a comes off the tooth 7a.

In this way, smooth rotation can be achieved by repeating the operation of one seven-cut machine mechanism in sequence for the second, third, and fourth. That is, the four 7-actuator mechanisms 1 in FIG. n.

In (2) and (2), to explain with reference to FIG. 4, at timing t0, the positions of the claws of each of the seven cutiators are
O), ■ is (0, ΔY), ■ is (ΔX, ΔY), ■ is (
ΔX, 0). Then, at the next timing t, I is (ΔX, O), ■ is (0, 0), and ■ is (0, Δ
Y), ■ is (ΔX.

As explained in Figure 2, (0, O) → (Δ
Change the position of the claw as follows: X, 0) → (ΔX, ΔY) → (0, ΔY). Figure 5 shows this in a table.

In this way, the toe 4a is always engaged with the rotor 7 at a certain timing. By repeating these four timings, the rotor 7 can rotate smoothly. Of course, the rotation in the B direction is also the same as (0,
This is possible by changing the position of the claw as follows: 0), (0, ΔY) → (ΔX, ΔY) → (ΔX, 0).

Although this embodiment shows the case of four actuator mechanisms, a case of two actuator mechanisms is also possible. For example, actuator ■,
The combination of (2) is also possible.

Moreover, three cases are also possible by sequentially changing the position of the actuator toe as shown in FIG.

[Effects of the Invention] As explained in detail above, according to the micro-rotation motor of the present invention, the rotor is rotated by the micro tooth profile and pawls by utilizing the micro expansion and contraction of the piezoelectric element, so that it is possible to rotate gear trains, etc. This has the effect of making it possible to obtain minute rotations with high precision and excellent resolution without any intervention. Specifically, by setting the amount of expansion and contraction of the laminated piezoelectric element to the pitch of the tooth profile, it is possible to realize a minute rotation motor with a resolution of about 171,000. Furthermore, increasing the diameter of the rotor will improve resolution.

Furthermore, since there is no need to obtain minute rotation through a gear train or the like, it is possible to construct various types of equipment with a simple structure and excellent mechanical precision without increasing the number of parts.

Furthermore, since the piezoelectric element is an element with excellent electromechanical conversion efficiency, it has the effect of realizing a small and lightweight micro-rotary motor. Therefore, it can be expected that various devices adopting this technology will also be made smaller and lighter.

4,

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the operation of an embodiment of the micro rotary motor according to the present invention. l... Frame, 2, 3... Piezoelectric element, 2a. 3a...Hinge, 4...Actuator, 4a...Claw, 5...Bearing, 6...
...Rotating shaft, 7...Rotor, 7a...
・Teeth.

Claims (1)

[Claims] A rotor that is directly connected to a rotating shaft and has a uniform fine tooth profile around the periphery, an actuator that has fixed claws that fit into the tooth profile, and first and second piezoelectric elements arranged orthogonally to each other that drive the actuator. What is claimed is: 1. A micro-rotary motor characterized by having an element.