JPH0771557A - Direct acting conversion/friction driving device - Google Patents

Abstract

PURPOSE:To realize the accurate propulsion of a slider, in a direct acting conversion/friction driving device in which the slider is abutted on an output shaft so that it is moved straight forward by the friction with the output shaft, by providing a backup roller that is eccentrically provided on the opposite side to the output shaft of the slider for giving a preload to the slider. CONSTITUTION:A direct acting conversion/friction driving device is used in such a case that the rotational motion of a turning shaft is converted into the rectilinear motion of a slider for carrying out accurate positioning in a machine tool or the like, and a slider 27 that performs rectilinear motion is abutted on an output shaft 25 to which the rotation of a servomotor 20 is transmitted via a planetary roller speed reducer 38, and also a backup roller 29 is abutted on the back side of the slider 27. The roller shaft 28 of the backup roller 29 is eccentrically supported with an eccentricity of e. Accordingly, by turning the roller shaft 28 with an angle theta of rotation in such a condition that the stopper bolt 34 of a stopper 32 locked by a stopping pin 33 has been loosened, a preload is given to the slider 27 for bringing it pressedly into contact with the output shaft 25. Thereby, a desired propulsion force is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine tool, a printing machine,
The present invention relates to a linear motion conversion friction drive device applied to various machines that require precise positioning by converting rotational motion of a rotary shaft into linear motion of a slider such as a handling machine.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory view of a conventional direct-acting conversion friction drive device used for various machines that require precise positioning by converting rotational motion of a rotary shaft into linear motion of a slider. In FIG. 2C, the slider 102 is moved straight in the X direction by rotating the pinion roller 101 mounted on the shaft of the actuator 100. At this time, the pinion roller 100 and the slider 1
No. 02 is pressed against each other with a preload P, and the propulsive force Q of the slider 102 is obtained by the frictional force. A movement amount sensor 103 is connected for positioning the slider 102 in the X direction.

In FIGS. 1A and 1B, a frame 1 is rotatably provided with a roller 3 fixed to an input or output shaft 2. Two rollers 4 facing the roller 3
Is rotatably provided on the frame 1. Roller 3,
A bar 5 is sandwiched between the upper and lower sides of the bar 4. Long grooves 9 which are long in the longitudinal direction and have a tapered cross section are provided on both side surfaces of the bar 5, and a thin portion 10 is provided between the bottoms of the both long grooves 9. A plurality of wedge-shaped members 6 having a wedge-shaped cross section and having the same length as the bar 5 are fitted in the long grooves 9, and are tightened by a plurality of bolts 7 in a direction in which they approach each other. A disc spring 8 is inserted around the bolt 7 between the bottom of the long groove 9 and the top of the wedge-shaped member 6. When the bolt 7 is loosened, the disc spring 8 allows the wedge-shaped member 6 to come out of the long groove 9. The distance between the rollers 3 and 4 is slightly larger than the height of the bar 5, and when the wedge-shaped member 6 fitted on the bar 5 is tightened with the bolts 7,
The thin portion 10 of the bar 5 extends within the elastic limit, and the upper and lower surfaces of the bar 5 are pressed against the rollers 3 and 4 and are preloaded so that a required frictional force is obtained. The rollers 3, 4 and the bar 5 are made of a metal material selected to obtain required strength, elasticity and friction coefficient.

In such a state, the shaft 2 is rotated with a constant rotational force, or the bar 5 is pulled with a constant tensile force. The movements of the shaft 2 and the bar 5 are transmitted evenly to each other, and
The tightened state of each bolt 7 is adjusted so that the transmission force is sufficient, and the rollers 3, 4 and the bar 5 are preloaded. Then, the bolt 7 is stopped. With this adjustment, the roller 3 and the bar 5 do not slip and there is no backlash, so that the mutual movements are smoothly transmitted by the frictional force. By tightening the wedge-shaped member 6 with the bolt 7 and extending the thin portion 10 of the bar 5 to generate the pressing force between the bar 5 and the roller 3, the pressing force can be made extremely strong and the bolt 7 can be prevented from rotating. By doing so, the pressing force is kept constant without loosening.

[0005]

In the conventional linear motion conversion friction drive device as described above, the preload P for converting the bar 5 into the linear motion by the propulsive force Q by the frictional force is the wedge member 6.
The bar 5 inevitably elastically deforms in order to generate
There is a drawback that the bar 5 is deformed in the longitudinal direction and the straightness of the bar 5 deteriorates. In addition, the number of bolts 7 and other components required for tightening the wedge-shaped member 6 increases, which is expensive.

[0006]

SUMMARY OF THE INVENTION A direct-acting conversion friction drive device according to the present invention is intended to solve the above-mentioned problems, and a slider is provided in contact with a rotating output shaft to move straight by friction with the output shaft. In the direct-acting conversion friction drive device, a backup roller provided eccentrically on the opposite side of the slider from the output shaft is provided to apply a preload between the slider and the output shaft.

Further, the direct-acting conversion friction drive device according to the present invention is a direct-acting conversion friction drive device in which a slider is provided in contact with a rotating output shaft and moves straight by friction with the output shaft. The backup roller is provided on the side opposite to the output shaft and expands in the circumferential direction when tightened in the axial direction to provide a preload between the slider and the output shaft.

Further, the direct-acting conversion friction drive device according to the present invention is a direct-acting conversion friction drive device in which a slider is provided in contact with a rotating output shaft and moves straight by friction with the output shaft. The backup roller is provided on the side opposite to the output shaft so as to be movable toward the slider and presses the slider against the output shaft to apply a preload between the slider and the output shaft.

[0009]

That is, in the linear motion conversion friction drive device according to the present invention, the slider is provided in contact with the rotating output shaft, and the slider is provided in the linear motion conversion friction drive device which moves straight by friction with the output shaft. A backup roller is eccentrically provided on the opposite side to preload between the slider and the output shaft.By adjusting the rotation angle in the circumferential direction of the eccentrically provided backup roller, the slider and the output shaft are adjusted. A preload can be arbitrarily applied to the shaft by a simple mechanism.

Further, in the linear motion conversion friction drive device according to the present invention, a slider is provided in contact with the rotating output shaft, and the slider output shaft of the linear motion conversion friction drive device moves straight by friction with the output shaft. When a backup roller is provided on the opposite side and it is tightened in the axial direction, it expands in the circumferential direction to give a preload between the slider and the output shaft.Tighten the backup roller in the axial direction and expand it in the circumferential direction Crowning deformation By doing so, a preload can be arbitrarily applied between the slider and the output shaft with a simple mechanism.

Further, in the direct-acting conversion friction drive device according to the present invention, a slider is provided in contact with a rotating output shaft, and a slider is provided in the direct-acting conversion friction drive device which moves straight by friction with the output shaft. A backup roller is provided on the opposite side so as to be movable toward the slider, and the slider is pressed against the output shaft to apply a preload between the slider and the output shaft. The backup roller can be moved toward the slider. Thus, a preload can be arbitrarily applied between the slider and the output shaft with a simple mechanism.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a direct-acting conversion friction drive device according to a first embodiment of the present invention. In the figure, the linear-motion conversion friction drive device according to the present embodiment is used in various machines such as machine tools, printing machines, and handling machines that need to perform precise positioning by converting the rotational motion of a rotary shaft into a linear motion of a slider. As shown, the motor shaft 21 of the servomotor 20 is integrated with the sun roller of the planetary roller speed reducer 38. The planetary roller reducer 38 is the planetary roller 2
2. It is composed of an elastic ring 23, a planet pin 24, an output shaft 25, etc. described in, for example, Japanese Patent Laid-Open No. 54-111049. The output shaft 25 of the planetary roller speed reducer 38 is a pinion roller for converting linear motion, and is supported by a bearing 26. A slider 27 and a backup roller 29 that move in a straight line are brought into contact with the pinion roller of the output shaft 25, and the backup roller shaft 28 of the backup roller 29 receives an eccentric amount e to obtain a propulsive force Q of the slider 27.
It is eccentric and has an eccentric axis. The backup roller shaft 28 is supported by a bush bearing 31, and the stop pin 33
When the stopper bolt 34 of the stopper 32, which is prevented from being rotated by, is loosened and rotated at the rotation angle θ in the circumferential direction, the preload P acts on the slider 27 and is brought into pressure contact with the pinion roller of the output shaft 25. Q can be obtained. The position of the backup roller shaft 28 is fixed by the stopper 3
This is done by tightening the second stopper bolt 34. The linear motion converting portion is supported by a casing 36, and is connected to the planetary roller reducer 38 with a fixing pin 35 with a bracket 39 of the planetary roller reducer 38 with a degree of freedom.

As described above, in the linear motion conversion friction drive device according to the first embodiment, the backup roller 29 is supported in order to narrow the pinion roller of the output shaft 25 which rotates and the slider 27 which moves linearly. The backup roller shaft 28 is an eccentric shaft, and by rotating this eccentric shaft, the preload P can be arbitrarily applied to the slider 27.
The eccentric shaft of the slider 27 depending on the size of the rotation angle in the circumferential direction.
The preload for can be set freely. Further, since the pinion roller of the output shaft 25 is supported by the left and right bearings 26, the backup roller 29 to the slider 27 are supported.
Does not bend and deform even when preloaded through The pinion roller side of the output shaft 25 is supported so as not to interfere with the bearing 26 of the pinion roller of the output shaft 25 and the bearing supporting the output shaft of the planetary roller speed reducer 38 or the servomotor 20. The casing 36, the planetary roller speed reducer 38, and the casing on the servo motor 20 side are provided separately. Since the backup roller shaft 28 of the backup roller 29 is an eccentric shaft, the preload P on the slider 27 can be accurately and easily obtained by rotating the backup roller shaft 28. Since the preload P is obtained in proportion to the rotation angle θ of the backup roller shaft 28 where the backup roller 29 is eccentric, the propulsive force Q can be set accurately. Further, since both ends of the pinion roller of the output shaft 25 are supported by the bearings 26, even if the preload P by the backup roller 29 is applied, the pinion roller is not bent or deformed so that an accurate propulsive force Q can be obtained. The positioning accuracy can be greatly improved. Further, the preload P can be set high and a high propulsive force Q can be obtained. Further, since the linear motion converting portion and the planetary roller reducer 28 are not connected to the rigid, the bearing 26 supporting the pinion roller of the output shaft 25 and the bearing supporting the output shaft of the planetary roller reducer 38 interfere with each other. Therefore, the damage of the bearing 26 can be avoided. Further, the mechanism for generating the preload P can be simplified and the cost can be reduced.

FIG. 2 is an explanatory view of a direct-acting conversion friction drive device according to a second embodiment of the present invention. In the figure, the direct-acting conversion friction drive device according to the second embodiment has substantially the same structure as the direct-acting conversion friction drive device according to the first embodiment.
The mechanism for applying the preload P to the backup roller 50 is different. That is, as shown in the figure, the backup roller 5
Reference numeral 0 indicates a thin hollow cylinder, into which a backup roller shaft 54 is inserted and fixed by a tightening adjustment nut 51 via a spacer 52. Both ends of the backup roller shaft 54 are supported by bearings 53. When the tightening adjustment nut 51 is tightened through the spacer 52, the tightening force F from the side surface acts on the backup roller 50, and the backup roller 50 expands in the circumferential direction of the rolling surface and undergoes crowning deformation. Due to this amount of deformation, the preload P acts on the slider 27 and is narrowed between the slider 27 and the pinion roller of the output shaft 25, so that a propulsive force Q for linearly moving the slider 27 is obtained.

As described above, in the linear motion conversion friction drive device according to the second embodiment, the backup roller 50 is formed in a thin hollow shape, and the rolling surface of the backup roller 50 is circumferentially moved by the tightening force from the side surface. The slider 27 is swollen within the elastic deformation limit, and the preload P can be arbitrarily applied to the slider 27 with this crowning amount of several μm, and the backup roller 50 moves from the side surface in the circumferential direction of the rolling surface. The preload P can be freely set on the slider 27 by swelling and crowning deformation due to the action of the tightening force. The backup roller 50 bends and deforms within the elastic deformation limit. As a result, errors in manufacturing and assembling such as flatness of the slider 27, runout of the pinion roller, and the backup roller 50 are eliminated.
In addition to the fact that the elastic deformation is absorbed and the accurate propulsive force Q is obtained, the same operation and effect as the direct-acting conversion friction drive device according to the first embodiment can be obtained.

FIG. 3 is an explanatory view of a direct-acting conversion friction drive device according to a third embodiment of the present invention. In the drawing, the direct-acting conversion friction drive device according to the third embodiment has substantially the same structure as the direct-acting conversion friction drive device according to the first and second embodiments. Output shaft 2 of roller reducer 38
No. 00 pinion roller is not supported by bearings. The backup roller 201 is supported by a bearing 202, and the bearing 202 is supported by a supporting member 203 thereof. The support member 203 is guided by the casing 207 of the linear motion converting portion and is precisely fitted with a gap of several μm. A spring member 204 is sandwiched between the support member 203 and the push plate 205. When the tightening bolt 209 with a load converter is rotated, the support member 203 is pressed toward the slider 27 side via the spring member 204 by the screw portion of the pressing plate 205, so that the preload P acts from the backup roller 201 and the slider moves. The propulsive force Q of the linear motion of 27 is obtained. A strain gauge 210 is attached to the tightening bolt 209 of the load converter in order to measure the preload P, and the preload P is measured by measuring the strain amount of the tightening bolt 209.
Is understood. In the figure, reference numeral 206 is a retaining ring, and 208 is an upper lid casing.

As described above, in the direct-acting conversion friction drive device according to the third embodiment, the support member 203 for supporting the entire backup roller 201 is guided by the casing so as to operate only in the vertical direction, and the spring member 204 is provided. The preload P can be measured by the tightening bolt 209 equipped with a load converter via it, and the optimum preload P can be arbitrarily given to the slider 27. The preload P on the slider 27 is guided by the cylinder and tightened by a tightening bolt 209 with a load converter via a spring member 204.
Can be freely set while finely adjusting. In the backup roller 201, the support member 203 is guided by the casing 207 of the linear motion converting portion with a precise fitting of several μm, so that the preload P can be easily obtained, and
Since the unbalanced load does not act between the backup roller 201, the slider 27, and the pinion roller, the accurate propulsive force Q and the superposition of the slider 27 are performed with high accuracy. Further, since the spring member 204 absorbs errors in manufacturing and assembling such as flatness of the slider 27, runout of the pinion roller and the backup roller 201, accurate propulsive force Q and super-precision positioning accuracy of the slider 27 are facilitated. can get.
Further, since the preload P can be easily measured by the tightening bolt 209 with the load converter, the preload P can be set more accurately, and the backup roller 201 and the slider 2 can be set.
7. The seizure and wear of the pinion roller of the output shaft 200 are prevented, and the durability is remarkably improved. Further, the mechanism and mechanism for generating the preload P can be made simple and inexpensive, and the same actions and effects as those of the direct-acting conversion friction drive devices according to the first and second embodiments can be obtained.

[0018]

The direct-acting conversion friction drive device according to the present invention is constructed as described above, and since a preload can be arbitrarily applied between the slider and the output shaft by a simple mechanism, it is appropriate. By applying the preload, the thrust force of the slider can be set accurately, and the positioning accuracy of the slider is significantly improved.

[Brief description of drawings]

1 (a) is a sectional view of a direct-acting conversion friction drive device according to a first embodiment of the present invention, FIG. 1 (b) is a view taken in the direction of arrow B in FIG. 1 (a), and FIG. c) is an explanatory view of the operation.

FIG. 2 is a sectional view of a linear motion conversion friction drive device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a direct-acting conversion friction drive device according to a third embodiment of the present invention.

FIG. 4 (a) is a front view of a conventional linear motion conversion friction drive device, FIG. 4 (b) is a sectional view taken along line bb in FIG. 4 (a),
FIG. 6C is an explanatory diagram of its operation.

[Explanation of symbols]

 20 Servo Motor 21 Motor Shaft 22 Planetary Roller 23 Elastic Ring 24 Planetary Pin 25 Output Shaft (Pinion Roller) 26 Bearing 27 Slider 28 Backup Roller Shaft 29 Backup Roller 30 Bearing 31 Bush Bearing 32 Stopper 33 Stopping Pin 34 Stopper Bolt 35 Fixing Pin 36 Casing 38 Planetary roller reducer 39 Bracket 50 Backup roller 51 Tightening adjustment nut 52 Spacer 53 Bearing 54 Backup roller shaft 200 Output shaft 201 Backup roller 202 Bearing 203 Support member 204 Spring member 205 Push plate 206 Stop ring 207 Casing 208 Upper lid casing 209 Load Tightening bolt with converter 209 Tightening bolt 210 Strain gauge

Claims (3)

[Claims] 1. A direct-acting conversion friction drive device in which a slider is provided in contact with a rotating output shaft and moves straight by friction with the output shaft, wherein the slider is eccentrically provided on the side opposite to the output shaft of the slider. A direct-drive conversion friction drive device comprising a pack-up roller for applying a preload between the output shaft and the output shaft. 2. A direct-acting conversion friction drive device in which a slider is provided in contact with a rotating output shaft and moves straight by friction with the output shaft, wherein the slider is provided on the side opposite to the output shaft of the slider and tightened in the axial direction. A direct-acting conversion friction drive device comprising a backup roller which expands in the circumferential direction when applied to apply a preload between the slider and the output shaft. 3. A direct-acting conversion friction drive device in which a slider is provided in contact with a rotating output shaft and moves straight by friction with the output shaft, and moves toward the slider on the side opposite to the output shaft of the slider. A direct-acting conversion friction drive device comprising a backup roller which is provided so as to press the slider against the output shaft to apply a preload between the slider and the output shaft.