JP3407080B2 - Precision positioning device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precision positioning device used for finely moving parts, manipulators and the like during assembly and adjustment of facsimiles, laser printers, video recorders and the like.

[0002]

2. Description of the Related Art In recent years, along with the high performance of faxes and video records, it has been required to precisely position and fix optical elements such as CCDs and photodiodes and small parts such as magnetic heads of video recorders. ing.

Conventionally, when performing this precise positioning,
A micro-movement device using an impact force that uses a piezoelectric element is used. This device is composed of a moving body, a piezoelectric element attached to the moving body, and an inertial body that gives an impact force to the moving body by driving the piezoelectric element.

[0004]

In the conventional micro-moving device, the moving body is designed so that the frictional sliding surface of the support body receives an electromagnetic force or an electrostatic force.
Further, although it is held by the pressing force of the spring, there are the following problems.

(1) Since the axial cross section of the moving body, that is, the cross section in the direction perpendicular to the axial center of the moving body is a combination of a rectangle and an inverted triangle, the lengths of the sides are not equal. Therefore, since the frictional force on each surface of the moving body is not uniform, the moving body easily bends and stable sliding becomes difficult. In addition, it is troublesome to process the moving body with high accuracy.

(2) Since the frictional sliding surface of the support is scraped and worn by the edge of the moving body, the frictional force on each surface of the moving body becomes uneven. Therefore, the moving body cannot be smoothly slid. Further, when the pressing force of the spring is used, there is a problem that the frictional force cannot be made constant with respect to the movement of the shaft.

(3) Since the friction sliding surface of the support is long, undulation occurs on the sliding surface and the frictional force on each surface of the moving body changes. Therefore, stable sliding becomes difficult. or,
It is more difficult and troublesome to obtain the flatness of a long friction sliding surface compared to a short one.

In view of the above circumstances, an object of the present invention is to allow a moving body to slide stably for a long period of time.

[0009]

SUMMARY OF THE INVENTION The present invention is a precision positioning device in which a moving body that slides by driving a piezoelectric element is held by a support through a friction member, the moving body having an axial section. It is an object of the present invention to achieve the above object by a precision positioning device which is formed in a regular polygonal shape, and friction members having the same pressure receiving area are brought into contact with the respective surfaces at the same pressure.

[0010]

When a voltage is suddenly applied to the piezoelectric element, the piezoelectric element rapidly expands and slides the moving body. This moving body is formed in a regular polygonal shape in its axial cross section, and since the friction member is in contact with each surface at the same pressure, a uniform frictional force is generated on each surface. Therefore, the moving body slides smoothly while being guided by the friction member.

[0011]

Embodiments of the present invention will be described with reference to the accompanying drawings. An element 1 such as a piezoelectric element, an electrostrictive element, or a magnetostrictive element (hereinafter, simply referred to as a piezoelectric element) 1 is connected to a metallic moving body 3 via a flange 2. The piezoelectric element 1 is housed in the inertial body 5, and the moving body 3 is held by the support 6 on the floor surface F.

The moving body 3 is a regular polygon having an axial section, for example, FIG.
As shown in FIG. 5, each side is formed in a square shape having a length L and arranged in a rhombus shape. Each surface 3a, 3b, 3 of the moving body 3
The friction members 8a, 8b, 8c, 8d are provided at c and 3d, and each of the friction members 8a to 8d is a substantially square plate body, and the length of one side is one side of the square. Is formed to be substantially equal to the length L. One set of friction members 8a to 8d of these four plates are arranged in two sets, that is, a front set A and a rear set B, with a space in the axial direction. Tip 3A of moving body 3
Are provided so as to project from the front group A.

The friction members 8c and 8d are fixed to the V-shaped groove 10 of the receiving member 6R of the support 6, and the friction members 8a and 8b are fixed to the inverted V-shaped groove 12 of the pressing member 11. ing.

The pressing member 11 is housed in the U-shaped portion 13 of the support 6, and the coil groove 16 is housed in the spring groove 14 at the upper part thereof.

The elastic force of the coil spring 16 is adjusted by a pressure adjusting screw (not shown).

Reference numerals 31 and 32 are sensors arranged between the friction members 8a to 8d, for example, limit switches, and scales for measuring the moving distance.

The operation of this embodiment will be described. The pressure adjusting screw is rotated to adjust the force for pressing the pressing member 11 of the coil spring 16, and the friction members 8a to 8d of the two sets A and B are adjusted.
The pressing force of is adjusted so that the frictional force of each member 8a to 8d becomes uniform.

The moving body 3 moves in the direction of arrow A35 by abruptly expanding the piezoelectric element 1 to the extent that it overcomes the static friction force between the moving body 3 and the moving body 36 through the striking member 35. Give a shock to. Therefore, the movable body 36 moves in the direction of arrow A36 in a state in which a beading has occurred.

After that, the piezoelectric element 1 returns to the original length while slowly contracting, so that the moving body 3 is held by the static friction force during this period. The movement is suddenly stopped when the piezoelectric element 1 returns to the original length. At this time, the inertial body 5 collides with the moving body 3, and the moving body 3 overcomes the static friction force and moves in the direction of arrow A35, and impacts the moving body 36 via the striking member 35. give. Therefore, the impact body 36 is indicated by an arrow A in a state where a collision occurs.
Move in 36 directions. By repeating this process as one cycle, the movable body 36 reaches the target position indicated by the chain line.

When the moving body 3 slides, each friction member 8
Since a to 8d have the same pressure receiving area and the same frictional force is generated, the moving body 3 slides straight while being guided by the friction members 8a to 8d.

Since the tip 3A of the moving body 3 always projects from the tip portions of the friction members 8a to 8d of the front group A, even if the moving body 3 slides, the edge 3B of the tip 3A of the moving body 3 causes the movement. The friction members 8a to 8d are not scraped to cause uneven wear. Therefore, since the frictional force can be maintained in a well-balanced manner, the moving body can be smoothly slid.

Further, since the front set A and the rear set B are provided with a space in the axial direction, compared with the case where the friction members are not divided into two sets A and B and are constituted by one friction member, In addition to requiring less flatness, the length of surface contact is shorter than in the prior art, so that waviness on the contact surface is eliminated. Therefore, the frictional force does not change depending on the contact location. Further, the precision positioning device can be controlled with high precision by the sensor 32 provided in the space of the friction members of the two sets A and B.

The present invention is not limited to the above, but may be configured as shown in FIG. 5, for example. The difference between this embodiment and the above-mentioned embodiment is that the moving body 46 is formed in an inverse regular shape in axial section, and the friction members 48a, 48b, 48 are provided on each side thereof.
c is provided.

[0024]

Since the present invention is configured as described above, it has the following remarkable effects. (1) Since the moving body has a regular polygonal axial cross section and friction members having the same pressure receiving area are brought into contact with the respective surfaces under the same pressure, the moving body slides smoothly while being guided by the friction member. To do. As a result, each surface of each friction member is worn on average, so that the frictional force can be kept constant for a long period of time. Further, since the overall frictional force of the device hardly changes regardless of the direction of inclination, it is optimal for manipulators of automatic machines that are used by moving it in various directions. (2) Since the tip of the moving body is projected from the tip of the friction member, even if the moving body slides, the edge of the tip does not scrape the friction member. Therefore, it becomes possible to obtain a stable frictional force for a long period of time, and it is most suitable for recent positioning devices and automatic machines that require maintenance-free. (3) Since a plurality of sets of friction members are arranged with a space in the axial direction, the length of the friction surface can be shortened as compared with the conventional example. Therefore, unlike the conventional case, the waviness of the friction surface does not occur, and the frictional force does not change depending on the contact location. Therefore, the moving body can be slid stably. Also,
Since a sensor such as a limit switch can be incorporated in the space, the device can be easily automated.

[Brief description of drawings]

FIG. 1 is a partially sectional front view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

3 is a sectional view taken along line III-III in FIG.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a cross-sectional view showing a second embodiment of the present invention and is a view corresponding to FIG.

[Explanation of symbols]

1 Piezoelectric element 3 moving bodies 6 support 8a Friction member 8b Friction member 8c friction member 8d friction member

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-123970 (JP, A) JP 5-72361 (JP, A) JP 6-241779 (JP, A) Actual development Sho 60- 171093 (JP, U) Actual Kaihei 2-91992 (JP, U) Japanese Patent Publication 5-19391 (JP, B2) Actual Public Publication 5-1992 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02N 2/00 B23Q 5/28 F16C 29/02 G12B 5/00

Claims (6)

(57) [Claims] 1. A moving body that slides by driving a piezoelectric element,
A precision positioning device held on a support through a friction member, wherein the moving body is formed in a regular polygonal shape in axial section, and frictional members having the same pressure receiving area are brought into contact with the respective surfaces at the same pressure. A precision positioning device characterized by the above. 2. A moving body that slides by driving a piezoelectric element,
A precision positioning device held on a support through a friction member, wherein the moving body is formed in a regular polygonal cross section, and frictional members having the same pressure receiving area are brought into contact with the respective surfaces at the same pressure. A precision positioning device characterized in that the tip of the moving body is projected from the tip of the friction member. 3. A moving body that slides by driving a piezoelectric element,
A precision positioning device held on a support through a friction member, wherein the moving body is formed in a regular polygonal cross section, and frictional members having the same pressure receiving area are brought into contact with the respective surfaces at the same pressure. A precision positioning device in which a plurality of sets of the friction members are arranged with a space in the axial direction. 4. The precision positioning device according to claim 1, 2 or 3, wherein the movable body has a square cross section. 5. The precision positioning device according to claim 1, 2 or 3, wherein the movable body has an equilateral triangular cross section. 6. The precision positioning device according to claim 3, wherein a sensor is provided in the space.