JPH062749A - Frictional driving mechanism - Google Patents

Abstract

PURPOSE:To displace a traction bar in stable manner by the revolution of a driving shaft even in the case where the parallelism of the frictional surface of the traction bar is inferior, the driving shaft is in eccentric or the shaft oscillation is generated. CONSTITUTION:A drive shaft back-up roller part 5 and a bar back-up roller part 4 are accommodated into an elastic case 3, and a driving shaft 1a and a traction bar 2 are nipped in the contact state between the drive shaft back-up roller part 5 and the bar back-up roller part 4. When the frictional surface 2a of a traction bar 2 tilts, the axial direction of the drive shaft back-up roller part 5 and the axial direction of the bar back-up roller part 4 are tilted by the deformation of the elastic case 3, and the bar back-up roller part 4 is set parallel to the frictional surface 2a of the traction bar 2.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a friction drive mechanism.
Specifically, it relates to a friction drive mechanism that converts the rotational movement of a drive shaft into a linear movement of a bar via friction.

[0002]

BACKGROUND ART AND ITS PROBLEMS FIG. 3 shows a conventional friction drive mechanism C.
Indicates. In the friction drive mechanism C, the notch 26
The two cylindrical holders 26 and 28 having a and 28a are arranged so that the notches 26a and 28a face each other, and the drive shaft 2 of the drive motor 21 is placed in one holder 28.
The backup roller 22 is rotatably held in the other holder 26 by inserting 1a. The traction bar 23 has notches 26a, 2 for the upper and lower holders 26, 28.
8a, the upper and lower friction surfaces are in contact with the backup roller 22 and the drive shaft 21a through the notches 26a and 28a. In addition, the backup roller 22
The holder 26 holding the is movable in the vertical direction while maintaining the parallel with the drive shaft 21a.
The leaf spring 27 elastically urges the traction bar 23 side, and as a result, the traction bar 23 is elastically sandwiched between the backup roller 22 and the drive shaft 21a. Further, the traction bar 23 is guided by the notches 26a and 28a so as not to swing laterally.

When the drive shaft 21a is rotated,
The traction bar 23 is slid in the longitudinal direction by the frictional force between the drive shaft 21a and the traction bar 23. Further, the elastic force of the leaf spring 27 causes the traction bar 23 to come into pressure contact with the drive shaft 21a with a constant pressing force,
A constant frictional force is generated between the traction bar 23 and the drive shaft 21a to prevent slippage between the traction bar 23 and the drive shaft 21a.

However, such a friction drive mechanism C
Therefore, when the parallelism between the upper and lower friction surfaces of the traction bar 23 is poor, or the parallelism between the drive shaft 21a and the backup roller 22 is poor, the outer peripheral surface of the drive shaft 21a and the traction bar 23 are The degree of contact with the friction surface and the degree of contact between the backup roller 22 and the friction surface of the traction bar 23 change, and sufficient frictional force cannot be obtained due to pressure fluctuation between the drive shaft 21a and the backup roller 22. 23 could not be displaced precisely.

When the drive shaft 21a is eccentric or shaft runout occurs, the applied pressure is not evenly distributed on the contact surface, the contact pressure becomes uneven, and the frictional characteristics fluctuate. There was a possibility.

Further, since the holder 26 holding the backup roller 22 is biased by the leaf spring 27, when the drive shaft 21a is eccentric or the shaft is shaken, strong vibration or impact is generated, the leaf spring 27 is elastic. The drive shaft 21a and the backup roller 22 are momentarily separated from each other by being bent and bent,
There is a risk that the drive shaft 21a may idle or cause a change in pressurization.

FIG. 4 is a perspective view showing another conventional friction drive mechanism D. As shown in FIG. In this friction drive mechanism D, a barrel ring 35 is fixed to a drive shaft 31a of a drive motor 31, and a backup roller 32 that is opposed to the drive shaft 31a substantially in parallel.
Also, the barrel ring 35 is fixedly attached, and the cross section of the friction surface 34 of the traction bar 33 is formed into a concave curved surface having a curvature smaller than that of the barrel ring 35. As shown in FIG.
The friction surface 34 of the traction bar 33 is sandwiched between the barrel-shaped ring 1a of the backup roller 32 and 1a.

Therefore, even if the parallelism between the drive shaft 31a and the backup roller 32 is poor as shown in FIG. 5B, or if the traction bar 33 is twisted as shown in FIG. The contact position between the outer peripheral surface of the barrel ring 35 and the friction surface 34 of the traction bar 33 changes in the width direction of the traction bar 33 to maintain contact.

However, such a friction drive mechanism D
In that case, there is a drawback that the contact area between the traction bar 33 and the barrel roller 35 is smaller than the width of the traction bar 33, and a large frictional force cannot be transmitted. Further, the drive shaft 31a and the backup roller 32
Is fixed to a rigid body at a certain distance, so that when the backup roller 32 is tilted or the traction bar 33 is twisted, it is possible to prevent a large change in pressurization and a change in frictional force. Since the contact position moves in the width direction of the traction bar 33, the applied pressure and the frictional force are likely to change, and the frictional characteristics are unstable. further,
Even when the drive shaft 31a or the like has eccentricity or shaft runout, the friction characteristics were unstable.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and its object is to make the friction surface of the traction bar poor in parallelism or to drive the drive shaft. An object of the present invention is to provide a friction drive mechanism capable of stably bringing the drive shaft and the bar into contact with each other even when the shaft is eccentric or shaft runout occurs.

[0011]

In the friction drive mechanism of the present invention, the bar contacts the outer peripheral surface of the drive shaft substantially orthogonal to the drive shaft, and the friction of the drive shaft and the bar causes the rotation of the drive shaft to be linear. A friction drive mechanism for converting into motion, a drive shaft backup roller portion for rotatably supporting the drive shaft,
A bar backup roller part that slidably supports the bar, a drive shaft backup roller part, and a bar backup roller part are fixedly attached so that the plate surface is substantially perpendicular to the rotation axis direction of each roller. A flexible plate, wherein the elastic flexible plate is substantially perpendicular to the drive shaft, and the drive shaft and the bar, which are in contact with each other at a substantially right angle, are sandwiched between the drive shaft backup roller section and the bar backup roller section. It has a feature.

[0012]

According to the present invention, the drive shaft backup roller portion and the bar backup roller portion are attached to the elastic bending plate substantially vertically, and the elastic bending plate is oriented substantially perpendicular to the drive shaft so that the drive shaft backup roller portion is provided. Since the drive shaft and the bar are sandwiched between the bar backup roller portion and the bar backup roller portion, the force sandwiched between the drive shaft backup roller portion and the bar backup roller portion ensures that the drive shaft and the bar are brought into contact with each other to provide a stable frictional force. It can be generated and the rotational force of the drive shaft can be converted into the thrust of the bar without loss.

Further, since the elastic bending plate elastically bends, the angle between the roller rotation axis direction of the drive shaft backup roller section and the roller rotation axis direction of the bar backup roller section changes, so that the friction surface of the bar is changed. Even if the parallelism between the bars is poor, the elasticity of the elastic bending plate can absorb the decrease in the parallelism of the bar. Can be followed. Therefore, even when the parallelism between the friction surfaces of the bar is poor, the drive shaft and the bar backup roller portion can be brought into close contact with the friction surface of the bar by the deformation of the elastic bending plate, and the elastic restoring force of the elastic bending plate drives the bar. The shaft and the bar backup roller portion can be elastically contacted with the friction surface of the bar, and the rotational force of the drive shaft can be transmitted to the bar without loss.

Further, since the drive shaft backup roller portion and the bar backup roller portion are fixedly attached to the elastic flexible plate, the distance between the drive shaft backup roller portion and the bar backup roller portion does not change, and the eccentricity of the rotary shaft is not changed. The shaft and the bar can be firmly clamped even if there is a shaft runout, a shock, or the like, and the drive shaft and the bar can be separated from each other and the drive shaft can be prevented from spinning instantly.

[0015]

1 is a front view showing a drive unit for a movable portion of an air slider 8 using a friction drive mechanism A according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view of the friction drive mechanism A. In this embodiment, the traction bar 2 is disposed substantially horizontally so as to be orthogonal to the drive shaft 1a of the drive motor 1 fixed horizontally on the base 10, and the traction bar 2 is disposed on the drive shaft 1a. 2 rides, and the contact holder B holds the contact state between the outer peripheral surface of the drive shaft 1a and the friction surface of the traction bar 2. Therefore, when the drive shaft 1a is rotated, friction between the drive shaft 1a and the traction bar 2 causes the traction bar 2 to move straight in the longitudinal direction, and the traction bar 2 is moved by a distance proportional to the rotation speed of the drive shaft 1a. Moving.

Reference numeral 8 denotes an air slider, which is a rail 11a.
A fixed pillar 11b provided at the end of the rail is fixed to the base 10, and the movable portion 8a is attached to the rail 11a supported in the air.
Is mounted so that it can run freely.

One end of the traction bar 2 is connected to the movable portion 8a of the air slider 8 via a joint 9, and the movable portion 8a can be slid along the rail 11a by moving the traction bar 2. . The joint 9 has a pair of upper and lower cutouts and a pair of left and right cutouts, and can be elastically bent up and down and left and right with respect to the sliding direction of the movable portion 8a, and the moving direction of the traction bar 2 and the movable portion 8a. Even when the sliding direction (direction of the rail 11a) does not match, the angular error between the moving direction of the traction bar 2 and the sliding direction of the movable portion 8a is absorbed to drive the movable portion 8a smoothly. Therefore, when the moving direction of the traction bar 2 and the sliding direction of the movable portion 8a are completely the same, the joint 9 is not necessary.

Next, the drive shaft 1a and the traction bar 2
The contact holder B connecting the two will be described. The elastic case 3 is, for example, one leaf spring 3a bent into a rectangular tube shape, and has both lower end portions 12a, 1 of the leaf spring 3a on the lower surface.
2b are overlapped, and the portions forming the main surfaces of both side surfaces are elastic bending plates 13. A drive shaft insertion hole 3b having a diameter larger than that of the drive shaft 1a is formed in each of the elastic bending plates 13 so as to face each other.

At the lower end of the elastic case 3, a drive shaft backup roller portion 5 is housed. The drive shaft backup roller unit 5 is composed of two rollers 5b rotatably supported on the upper surface of a support block 5a.
The distance between the outer peripheral surfaces of a is smaller than the diameter of the drive shaft 1a. The drive shaft backup roller unit 5 is a roller 5
It is delivered to the lower end portion between the elastic bending plates 13 such that the rotation axis direction of b is perpendicular to the elastic bending plates 13 and both ends 12 of the leaf spring 3 a located on the lower surface of the elastic case 3.
By fixing the screws 14 inserted into the a and 12b to the lower surface of the support block 5a, the drive shaft backup roller portion 5 is horizontally fixed to the lower portion of the elastic case 3 and both end portions 12a and 12b of the leaf spring 3a are fixed to each other. It is connected. In order to make both elastic flexible plates 13 easy to flex, the holes of both end portions 12a, 12b of the plate spring 3a through which the screw 14 is inserted are made long holes in the direction perpendicular to the elastic flexible plate 13 to make the plate spring 3a Both ends 12a and 12b may be displaced from each other. Thus, the drive shaft backup roller unit 5
In the state where is fixed to the lower part of the elastic case 3, the edges of the two rollers 5b project into the drive shaft insertion hole 3b.

An auxiliary plate 6 made of metal is fixed to the lower surface of the upper piece 15 of the elastic case 3 by welding, screwing, or any other method.
At least one female screw hole 16 is continuously formed in each of the male and female press holes, and a pressurizing adjusting screw 7 is screwed into each female screw hole 16 so as to be screwed in and out.

A bar backup roller section 4 is housed in the upper part of the elastic case 3. The bar backup roller unit 4 is formed by rotatably supporting two rollers 4b on the lower surface of a support block 4a.
It is delivered to the upper part between the elastic flexible plates 13 so that the direction of the rotation axis thereof is perpendicular to the elastic flexible plates 13 and at least vertically movable.

Since the bar backup roller portion 4 is not fixed to the elastic case 3, there is a risk that it will slide left and right within the elastic case 3 and fall out from the openings 17 on both side surfaces. In order to prevent this, a fall prevention piece (not shown) is folded from both side edges of the elastic flexible plate 13 toward the opening 17, or the both sides of the elastic flexible plate 13 are prevented from falling off so as not to connect the elastic flexible plates 13. A metal fitting (not shown) may be attached. Alternatively, a recess (not shown) into which the tip of the pressurization adjusting screw 7 fits is provided on the upper surface of the support block 4a of the bar backup roller unit 4, and the female screw hole 16 is formed.
The bar backup roller unit 4 may be positioned in the horizontal direction by fitting the tip of the pressurizing adjustment screw 7 attached to the recess into the recess so that the bar backup roller unit 4 does not move laterally.

Therefore, in this contact holder B, the roller 5b of the drive shaft backup roller portion 5 and the roller 4b of the bar backup roller portion 4 are parallel to each other when no load is applied. When the elastic bending plate 13 of the elastic case 3 is elastically deformed as shown by an arrow in FIG. 2, for example, the roller 5b of the drive shaft backup roller unit 5 and the roller 4b of the bar backup roller unit 4 are no longer parallel to each other and have an angle. You can

When the contact holder B is attached to the drive shaft 1a of the drive motor 1, the pressurizing adjustment screw 7 is retracted to lift the bar backup roller portion 4 in the elastic case 3 to drive the drive shaft backup roller portion. 5 and the bar backup roller part 4 are sufficiently spaced, the traction bar 2 is inserted into the elastic case 3 through the side opening 17 and is inserted between the drive shaft backup roller part 5 and the bar backup roller part 4. Let Then, the contact holder B is oriented so that the elastic bending plate 13 is perpendicular to the drive shaft 1a, and the contact holder B is positioned between the traction bar 2 inserted in the contact holder B and the roller 5b of the drive shaft backup roller unit 5. In this way, the drive shaft 1a is inserted into the drive shaft insertion hole 3b. After that, when each pressure adjusting screw 7 is tightened with an appropriate balance, the bar backup roller portion 4 is pushed down by the pressure adjusting screw 7, and when the pressure adjusting screw 7 is further tightened, the drive shaft 1a and the traction bar 2 are separated. The rollers 5b of the drive shaft backup roller unit 5 in a state where they are orthogonal to each other.
And the roller 4b of the bar backup roller unit 4 are sandwiched. On the other hand, the contact holder B is also attached to the drive shaft 1a of the drive motor 1 by sandwiching the drive shaft 1a and the traction bar 2 between the roller 5b of the drive shaft backup roller unit 5 and the roller 4b of the bar backup roller unit 4. ing.

As a result, the drive shaft 1a and the traction bar 2 come into contact with each other in a state where they are pressed and are in close contact with each other, and considering the deformation of the material, the friction surface 2a of the traction bar 2 is considered.
And the drive shaft 1a come into surface contact with each other, and a strong frictional force is obtained. Therefore, when the drive shaft 1a is rotated, the rotational force of the drive shaft 1a is converted into the thrust of the traction bar 2 by the frictional force. Further, by adjusting the tightening of the pressurization adjusting screw 7, the pressurization between the drive shaft 1a and the traction bar 2 can be adjusted.

Further, the friction surface 2a of the trunk bar 2
Even if the parallelism between the two is poor and the cross section of the trunk bar 2 is partially trapezoidal, the elastic case 3
The elastic bending plate 13 elastically bends so that the roller 4b of the bar backup roller unit 4 tilts following the angle of the friction surface 2a of the traction bar 2. Therefore, also in this case, the roller 4b of the bar backup roller unit 4 and the friction surface 2a of the traction bar 2 and the drive shaft 1a and the friction surface 2a of the traction bar 2 are always brought into close contact with each other, and the rotation of the rotation shaft 1a is reduced by the traction. It can be reliably transmitted to the bar 2.

Further, the contact holder B is not fixed to the base 10 or the like, but is made to float in the air so that the drive shaft 1
Since it is attached to a, the contact holder B moves following the movement of the drive shaft 1a even if the drive shaft 1a has eccentricity or shaft runout. Moreover, since the drive shaft backup roller portion 5 and the bar backup roller portion 4 do not elastically sandwich the drive shaft 1a and the traction bar 2 but fixedly sandwich them, the eccentricity of the drive shaft 1a and the shaft are prevented. The drive shaft backup roller unit 5 and the bar backup roller unit 4 do not separate from each other due to runout, impact or the like. Therefore, drive shaft 1
A momentary idle rotation of a does not occur, a stable frictional force can be generated between the drive shaft 1a and the trunk bar 2, and the traction bar 2 can be precisely displaced.

The present invention can be modified in various ways other than the above embodiment. For example, in the above embodiment, the traction bar is placed on the drive shaft, but conversely, the traction bar may pass under the drive shaft. Further, the bar backup roller unit may be composed of three rollers, and the arrangement of the rollers of the bar backup roller unit and the arrangement of the rollers and the drive shaft of the drive shaft backup roller unit are vertically symmetrical with respect to the traction bar. Good.

In the above embodiment, the elastic case including the two elastic bending plates is used. However, in order to make the elastic bending plate easy to bend, one elastic bending plate is removed except for one of the elastic bending plates. You may comprise an elastic case only with a board. Further, each of the drive shaft backup roller portion and the bar backup roller portion may be provided with a bearing or a bearing itself in order to smooth the rotation.

If a displacement actuator such as a piezoelectric element is inserted between the upper piece of the elastic case and the upper surface of the support block of the bar backup roller section instead of the pressurizing adjusting screw, a driving voltage is applied to quantitatively determine the displacement actuator. It is possible to obtain a proper pressurization. In this case, it is also possible to insert a displacement measuring element or the like in series with the driving displacement actuator, measure the applied pressure with the displacement measuring element, and manage the applied pressure.

[0031]

According to the present invention, the force sandwiched between the drive shaft backup roller portion and the bar backup roller portion can surely bring the drive shaft and the bar into contact with each other to generate a stable frictional force. The rotational force of can be converted into the thrust of the bar without loss.

Further, even if the parallelism between the friction surfaces of the bar is poor, the drive shaft and the bar backup roller portion can be brought into close contact with the friction surface of the bar by the deformation of the elastic bending plate, and the rotational force of the drive shaft is lost. Can be transmitted to the bar without.

Further, since the drive shaft backup roller portion and the bar backup roller portion are fixedly attached to the elastic bending plate, the distance between the drive shaft backup roller portion and the bar backup roller portion does not change, and the eccentricity of the rotary shaft is eccentric. The shaft and the bar can be firmly clamped even if there is a shaft runout, a shock, or the like, and the drive shaft and the bar can be separated from each other and the drive shaft can be prevented from spinning instantly.

[Brief description of drawings]

FIG. 1 is a front view showing a movable portion drive device of an air slider using a friction drive mechanism according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing the friction drive mechanism of the above.

FIG. 3 is a perspective view showing a friction drive mechanism according to a conventional example.

FIG. 4 is a perspective view showing a friction drive mechanism according to another conventional example.

5 (a), (b) and (c) are explanatory views of the operation of the above conventional example.

[Explanation of symbols]

 A friction drive mechanism B contact holder 1 drive motor 1a drive shaft 2 traction bar 3 elastic case 4 bar backup roller part 4b bar backup roller part roller 5 drive shaft backup roller part 5b drive shaft backup roller part roller 7 pressurization Adjustment screw

Claims (1)

[Claims] 1. A friction drive mechanism in which a bar contacts an outer peripheral surface of a drive shaft substantially orthogonally to the drive shaft, and friction of the drive shaft and the bar converts rotation of the drive shaft into linear motion of the bar. The drive shaft backup roller portion that rotatably supports the drive shaft, the bar backup roller portion that slidably supports the bar, the drive shaft backup roller portion and the bar backup roller portion, and the plate surface is in each roller rotation axis direction. An elastic bending plate fixedly attached so as to be substantially vertical, and the elastic bending plate being substantially vertical to the drive shaft,
A friction drive mechanism in which a drive shaft and a bar that are in contact with each other at substantially right angles are sandwiched between the drive shaft backup roller unit and the bar backup roller unit.