JPH11311269A - Friction adding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction adding device simple in constitution, easy to manufacture and having equivalent function. SOLUTION: A friction adding device 10 for adding friction to a positioning table device has a lever member 11 serving as a lever part formed by connecting a pair of lever faces 112 provided with brake shoes 13 at action points, opposedly to hold a friction added body in between and providing a connection part with a thin-walled elastic part 113 to form a fulcrum, an actuator 14 for imparting working force to a force point of the lever member 11, and a fitting member 12 serving as a fitting part of the lever part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a friction applying device for applying a friction to a moving body such as a positioning table to control the behavior of the moving body.

[0002]

2. Description of the Related Art Conventional friction applying devices of this type include:
For example, there is a damping block disclosed in Japanese Patent Application Laid-Open No. 7-54845. This is mounted on a linear motion guide device LG generally used as a device for transporting a positioning table body in order to control its damping property and rigidity. That is, as shown in FIGS. 10 and 11, the damping block 200 has an inverted concave shape that surrounds both side surfaces and the upper surface of the guide rail 400 of the linear motion guide device LG, and is straddled on the guide rail 400. Two brake shoes 340 opposed to a pair of left and right sides and separated from and brought into contact with the side surface of the guide rail 400, and a piston 344 sliding in the cylinder groove 320 as a hydraulic actuator for driving the two brake shoes are provided on both sleeves. Brake shoe support 300 in which is installed
It has. Further, each brake shoe support 300
A hydraulic switching circuit including a sub-hydraulic supply pipe 230 and a spring mechanism 250 for returning the brake shoe are disposed on both sides of the hydraulic pump.

The positioning table is fixedly supported on the upper surface of the damping block 200 and the upper surface of a slider (not shown) straddling the guide rail 400, and is guided to the guide rail 400 and conveyed to a predetermined position. When stopping, hydraulic pressure is sent to the piston 344 of the damping block 200 to move the brake shoe 340 forward, and the both sides of the guide rail 400 are strongly pressed to apply a brake, thereby attenuating the speed of the positioning table body. It can be accurately positioned at a predetermined position and stopped.
At the time of starting, when the working oil pressure is released by switching the oil pressure switching circuit 230 in the damping block 200,
The brake shoe 340 is automatically retracted by the action of the spring mechanism 250.

[0004]

However, in the above-mentioned conventional friction applying device, a pair of two opposing brake shoes are each provided with a hydraulic actuator for driving, and further a switching circuit for the hydraulic pressure is provided. Since the spring mechanism for returning the brake shoe is integrated in the damping block body, there is a problem in that the structure is extremely complicated, the number of components is large, and the manufacturing is not easy. Therefore, the present invention has been made in view of such problems of the related art, and an object of the present invention is to provide a friction applying device which is easy to manufacture with a simple configuration and has the same function.

[0005]

A pair of levers each having a brake shoe at an application point are connected to face each other so as to sandwich a body to be rubbed, and a lever is used as an elastic fulcrum at the connection part. A friction applying device, comprising: an actuator for applying an acting force to the force point of (1); and a mounting portion for the lever portion.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a first embodiment of a friction applying device of the present invention. FIG. 1 is a perspective view of a single unit, FIG. 2 is a side view, FIG. 3 is a front view, and FIG. IV
FIG. 5 is a front view of the precision positioning table equipped with the friction applying device of the present invention shown in FIGS. 1 to 4, and FIG. 6 is a side view thereof. First, the structure of the friction applying device 10 will be described. The main body of the friction applying device 10 includes two members having a spring property as described later, that is, a lever member 11 having a substantially H-shaped cross section and a cross section. It has a structure in which a mounting member 12 as a substantially concave mounting portion is integrally combined.

More specifically, in the lever member 11, the opposed vertical plate portion of the H shape forms a lever surface 112, and the pair of opposite lever surfaces 112, 112 They are connected by a plate portion 111. The horizontal plate 111
Is the base of the plate thickness t ₁ is the connecting portion between each lever surface 112, 112 to locally thin to form a fulcrum 113 of an elastic thin. Thereby, both lever surfaces 1
When a force in the direction of opening the opposing space is applied with one end of 12, 12 as the point of force, the opposite end of the thin lever fulcrum 113 becomes the point of action and pivots in the direction of closing the opposing space to perform the lever movement. . Brake shoes 1, which are friction members, are provided on opposing surfaces on the lower end sides of the lever surfaces 112, which are action points.
3 are fixed with mounting bolts 15 so as to oppose each other so as to sandwich the friction object. The brake shoe 13 is formed by, for example, cutting a central portion of a rectangular member in the axial direction from above and below so as to have a substantially H-shaped cross section, and providing a thin elastic portion 131 having a thickness t ₂ at the center portion. Thus, a flexible structure having a spring property rotatable around the shaft is provided. This allows
Even if the lower end side of the lever surface 112, which is the lever action point, is slightly inclined with respect to the rubbed surface, the contact surface of the brake shoe 13 can be pressed in parallel with the rubbed surface, and the And a uniform braking force can be applied. A friction material 132 is fixed to the brake surface by means such as adhesion.

The bottom plate 121 of the mounting member 12 is superimposed on the horizontal plate 111 of the lever member 11 configured as described above.
The vertical plate portion 112 of the H-shaped member and the vertical plate portion 122 of the concave member are combined so as to be located at right angles, and are integrally joined. The mounting member 12 is provided with openings (windows) 123 penetrating in the thickness direction in the vertical plate portions 122, 122 raised at both ends of the bottom plate portion 121. The opening 123 forms a thin elastic portion 124 having a thickness t ₃ between the left and right side end surfaces of the vertical plate portion 122, and the mounting member 12 has the same direction as the opposite direction of the two brake shoes 132. (Ie, a direction perpendicular to the direction of table movement)
Has a flexible spring property.

On the upper surface of the vertical plate portion 122, a screw hole 125 for a mounting screw is provided. A groove 121m is provided on the upper surface of the bottom plate 121 of the mounting member 12, and the piezo actuator 14 as a biasing means is mounted in the groove 121m so that the output surface thereof faces the lever surface 112. It is fixed with bolts 16.

FIG. 5 is a front view of the above-described friction applying device 10 mounted on a positioning table 17 which is a precision positioning device, and FIG. 6 is a side view thereof. This positioning table 1
Reference numeral 7 denotes a known linear motion guide device (linear guide) 20 which is installed in parallel on a base 171 with an interval therebetween, and one ball screw device 21 is disposed in parallel between them. Things are fine. That is, the linear guide 20 is mounted on the guide rail 201 having ball rolling grooves on both sides.
Bearing (slider) 20 that slides through the rolling of
The table 2 is mounted on the upper surface of the four sliders, and can be smoothly moved by being guided by the guide rail 201. The ball screw device 21 includes a ball screw shaft 211 and a ball nut 212 screwed to the ball screw shaft 211 via a ball, and both ends of the ball screw shaft 211 are rotated by support units 213 and 214 erected on a base 171. It is arranged freely supported. A motor 215 for rotational drive is attached to one end of the ball screw shaft 211, and the ball screw shaft 211 is driven in accordance with a command from a drive control device (not shown).
Is rotated to linearly move the ball nut 212 to a predetermined position, thereby performing precise positioning. The ball nut 212 is connected to the lower surface of the table 172.

The friction applying device 10 of the present invention is mounted on the lower surface of the table 172 of the positioning table 17. The mounting position is in the middle of the sliders 202 laid on the guide rails 201 of each linear guide 20 two by two.
Abut on the lower surface of the table 172, and
25 and is fixed by mounting bolts. Opposing brake shoes 13 of each friction applying device 10
2 and 132 are opposed to the guide rail 201 via a slight gap so as to sandwich the side surface of the guide rail 201.

Next, the operation of the friction applying device 10 will be described. When a predetermined voltage is not applied to the piezo actuator 14, no force acts on the force point of the lever surface 112 of the friction applying device 10.
There is a gap between 32, 132 and the side surface of the guide rail 201, and no braking force is applied. For example, the brake is applied when the table 172 is moved at a high speed to a predetermined position by the motor 215 of the positioning table 17 and then it is desired to stop accurately. This is performed by applying a predetermined voltage to the piezo actuator 14 of the friction applying device 10 to extend the length in the axial direction.

When the piezo actuator 14 extends,
The levers 11 are pressed against the inner surfaces of the levers 112, 112 of the lever member 11, and are pressed in a direction to increase the distance between the two surfaces. Then, the lower portions of the lever surfaces 112, 112 are rotated around the lever fulcrum 113, which is a thin elastic portion, as a fulcrum in a direction in which the distance between the both surfaces is reduced, and the friction member 1 of the brake shoe 13 at the lever action point.
32 are pressed against both side surfaces of the guide rail 201. A frictional force is generated by this pressing force, and the table 172 is braked. At this time, since the flexible structure of the brake shoe 13 functions and the friction member 132 is pressed in parallel to the side surface of the guide rail 201, uneven wear of the friction member 132 can be prevented.

The magnitude of the braking force by the piezo actuator 14 can be freely adjusted by controlling the magnitude of the voltage applied to the piezo element. That is, the applied voltage may be increased to increase the braking force. Conversely, to reduce the braking force, the applied voltage is reduced. Then, at the same time as the force acting on the lever surface from the piezo actuator 14 decreases, the brake shoe 13 retreats away from the guide rail 201 by the elastic restoring force of the thin elastic portion 113, and the frictional force decreases. Thereby, an optimal frictional force is given, and the controllability of the positioning of the table 172 can be improved. When the application of the voltage to the piezo actuator 14 is stopped, the piezo actuator 14 contracts and returns to the original length. At the same time, both the lever surfaces 112 and 112 of the lever member 11
With the elastic restoring force of 13, the brake returns to its original state and the braking is released.

During braking, the braking force acts on the table 172 via the mounting member 12 which is a fixed member in accordance with the extension force of the piezo actuator 14 acting on the force point of the lever surface 112, and at the same time, other forces are applied. For example, chattering force or the like is generated in the guide rail 201 in the orthogonal direction. However, in the friction applying device 10, the mounting member 12 has a flexible structure having a thin elastic portion 124 and has a flexible spring property in a direction perpendicular to the moving direction of the table 172. The effects of forces other than friction on 172 are eliminated.

FIG. 7 shows a second embodiment of the friction applying apparatus according to the present invention. The same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. In this embodiment, the friction applying device 10A is applied to a ball screw shaft 211 of a positioning table 17, and FIG. 7 is a front view thereof.

The friction applying device 10A of this embodiment is
Friction member 13 attached to friction surface of brake shoe 13
The second embodiment is different from the friction applying device 10 of the first embodiment in that the shape 2 is not a flat plate but a V-groove so as to easily hold the ball screw shaft 211. That is,
In the case of the friction applying device 10A, the driving of the piezo actuator 14 causes the brake shoe 13 to move the ball screw shaft 21
By pressing against 1, the ball screw shaft 211 is clamped to apply a brake. In the final stage of positioning the table 172, the radial vibration of the ball screw shaft 211 can be suppressed by friction, and as a result, the settling time of the table 172 can be reduced. The other configuration, operation, and effect are substantially the same as those of the first embodiment. It should be noted that the friction applying devices 10 and 10A shown in both the first and second embodiments are connected to the same positioning table 17.
In this case, the above-described respective effects can be obtained simultaneously.

FIGS. 8 and 9 show a third embodiment of the friction applying apparatus according to the present invention.
An embodiment will be described. The same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. In this embodiment, the friction applying device 10B
Is mounted on the positioning table 17B. The friction applying device 10B is different in lever type from that of the first embodiment. More specifically, the friction applying device 10 according to the first embodiment has a lever structure having a force point and an action point vertically above and below a fulcrum.
The lever B has a lever structure having a force point and an action point below the fulcrum. The lever member 11A has a U-shaped cross section (an inverted concave shape) instead of an H-shaped cross section. The first embodiment differs from the first embodiment in that a lever surface 112 is formed by a vertical plate portion and the upper ends of the lever surfaces 112 and 112 are connected by an orthogonal horizontal plate portion 111A. ing.

The horizontal plate portion 111A has a lever surface 112,
The thickness of the base, which is a connecting portion with the base 112, is locally reduced to form a thin fulcrum lever having fulcrum and both lever surfaces 112, 11 located below the horizontal plate portion 111A.
When a force in the direction to open the opposing gap is applied to the force point 2
The lower end serves as a point of action and pivots in a direction to open the opposing interval to perform a lever motion. The brake shoes 13 are respectively provided with friction materials 132 on opposing surfaces at the lower ends of the lever surfaces 112, which are action points.
The guide rail 201, which is a rubbed body, is fixed with the mounting bolts 15 so as to face each other so as to sandwich it. A thin elastic portion 131 of the brake shoe 13 is provided.
The flexible structure having the spring property and its function are the same as those of the first embodiment.

The upper surface of the bottom plate of the concave mounting member 12A is superimposed on the lower surface of the horizontal plate portion 111A of the lever member 11A thus constructed, and the two members 11A and 12A are integrally joined. The piezo actuator 14 is fixed to the lower surface of the member 12A with mounting bolts 16 so that the output surface thereof faces the point of force of the lever surface 112. Although not shown, the mounting member 12A includes:
An opening (window) for providing a flexible spring property in a direction perpendicular to the moving direction of the table is provided.

On the other hand, in the positioning table 17B, a linear motor 30 is used as a traveling drive device of the table 172 instead of the ball screw device 21 in the first embodiment.

In this embodiment, in a state where the actuator 14 of the friction applying device 10B is not driven, the brake shoe 13 is connected to the side surface of the guide rail 201 by the spring restoring force of the thin elastic portion at the lever fulcrum of the lever member 11A. It is in a state pressed against. When the actuator 14 is extended, the opposing lever surfaces 112, 11
A force acts on the second force point in a direction to widen the interval. By controlling the expanding force by controlling the voltage applied to the piezo actuator 14, the frictional force can be adjusted, and the optimal frictional force can be given to improve the controllability of the positioning of the table 172.

The positioning table 17B shown in FIGS.
When the power supply is suddenly turned off while the table 172 is being driven, the table 172 may fall in the case of a normal table apparatus. However, according to the third embodiment of the present invention, since the frictional force of the friction applying device 10B acts on the guide rail 201 when the actuator 14 is not driven, the friction applying device 10B serves as a brake for preventing the table 172 from dropping. Also works.

In each of the above embodiments, the piezo actuator 14 is used as the actuator of the friction applying device. However, the present invention is not limited to this. In addition, a fluid actuator such as pneumatic or hydraulic, or an electric actuator may be used. Such an electromagnetic actuator or the like can also be suitably used.

In addition, in order to apply the friction applying apparatus of the present invention to a positioning table, a linear guide that supports the table is mounted at an intermediate position between a plurality of sliders. You can also.

In each of the above embodiments, the lever members (11, 11A) forming the lever portion and the mounting members (12, 12A) forming the mounting portion are separately formed and are integrally superposed. Although the case of joining has been described, a configuration in which the lever portion and the attachment portion are integrally formed from the beginning may be employed.

Further, the friction applying device of the present invention is not limited to a positioning table, but can be suitably used for vibration suppression, braking, and the like for other frictional objects.

[0028]

As described above, according to the friction applying apparatus according to the present invention, the force and the fulcrum applied by the actuator to the leverage point by utilizing the leverage structure and making the leverage fulcrum portion elastic. With the elastic restoring force of the part, the brake shoe provided at the point of application of the lever is separated from and brought into contact with the surface to be rubbed, and the optimum frictional force is added, so the structure is extremely simple and it is easy to manufacture It works. Further, an actuator having a different driving principle can be selectively used in accordance with a difference in specifications, and an effect of high degree of freedom in design can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of a friction applying device according to the present invention.

FIG. 2 is a side view thereof.

FIG. 3 is a front view thereof.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 2;

FIG. 5 is a front view of a positioning table to which the friction applying device of FIG. 1 is mounted.

FIG. 6 is a side view of FIG. 5;

FIG. 7 is a front view of a positioning table equipped with a friction applying device according to a second embodiment of the present invention.

FIG. 8 is a front view of a positioning table to which a friction applying device according to a third embodiment of the present invention is mounted.

FIG. 9 is a side view of FIG.

FIG. 10 is a sectional view from the side of a linear guide on which a conventional friction applying device is mounted.

11 is a cross-sectional view from the top of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Friction adding device 10A Friction adding device 10B Friction adding device 11 Lever member 112 Lever surface 113 Thin elastic part 12 Mounting member 13 Brake shoe 14 Actuator

Claims (1)

[Claims] 1. A lever portion having a pair of lever surfaces having a brake shoe at an action point facing each other so as to sandwich a body to be rubbed, and a lever portion having an elastic fulcrum at the connection portion, and acting on a force point of the lever portion. A friction applying device, comprising: an actuator for applying a force; and a mounting portion for the lever portion.