JP3966653B2 - Linear disc brake - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a linear disc brake, and more particularly to a linear disc brake used when braking a linear motor drive stage.
[0002]
[Prior art]
In recent years, in an ultra-precision positioning stage using a servo actuator (actuator equipped with a servo motor), it has been required to accurately position the stage without trembling or shifting (hereinafter, without trembling or shifting). Positioning with high accuracy is called “setting”). In such setting, the requirement is becoming strict from the micron order to the nano order, and there is such a requirement particularly in the field of information equipment manufacturing apparatus and inspection apparatus.
[0003]
Here, with reference to FIG. 5, an outline of a precision positioning stage driven by a linear motor will be described.
[0004]
The precision positioning stage shown in the figure is driven by a linear motor 11, and the table (stage) 12 is driven and controlled by the linear motor 11 while being guided in a predetermined direction by a guide system 13, and moves to a desired position. The guide system 13 includes a support 13a, and the table 12 is supported on the support 13a by a guide surface 13b.
[0005]
As the guide system 13 , for example , pneumatic or gas static pressure guide is used.
[0006]
[Problems to be solved by the invention]
By the way, considering the stability of the conventional precision positioning stage, the stick slip that occurs when the stage is braked and stopped (triggering and slipping of the ball bearing when stopped) and the tripologue problem due to insufficient lubrication (relative movements affect each other) In the case of using a servo actuator, there is no influence on the influence of minute vibrations from the servo actuator. There is a problem that it is extremely difficult to set the stage at several to several tens of nanometer level. That is, when the stage is set, there is a problem that it is difficult to set the stage at the nano level due to friction of the guide system and vibration of the servo system when the servo is applied as in the prior art.
[0007]
An object of the present invention is to provide a linear disc brake capable of setting a stage at a nano level in a precision positioning stage.
[0008]
[Means for Solving the Problems]
According to the present invention, it is used in a precision positioning stage in which a movable table is moved to a target position by a servo mechanism provided in a linear motor, and is fixed along the moving direction of the movable table. A plate member fixed to a base; a spring brake that brakes the movable table with a central portion attached to the movable table and sandwiching the plate member; and an air cylinder that drives and controls both ends of the spring brake; The plate member and the spring brake are formed of the same material. When air is supplied to the air cylinder, the plate member is not caught by the spring brake , and the air cylinder includes first and second air cylinders. The first and second air cylinders are cylinders of the cylinder. Are arranged so as to have a predetermined angle with each other, and both end portions of the spring brake are fixed to the first and second air cylinders, respectively, and between the center portion and the both end portions. A linear disc brake characterized in that a pinching portion for pinching the plate member is formed .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings.
[0010]
With reference to FIG. 1, the precision positioning stage shown in the figure is provided with a linear disc brake, and the stage (movable table) 12 is controlled to be braked by this linear disc brake. As described with reference to FIG. 5, the movable table 12 is driven and controlled by a linear motor (not shown) while being guided in a predetermined direction by a guide system (not shown). Moving. The guide system includes a support, and the movable table 12 is supported on the support by a guide surface.
[0011]
Below the movable table 12, a plate 21 is disposed along the moving direction of the movable table 12, and the plate 21 is fixed to a fixed base 22 by bolts 21a. A mounting plate 23 is attached to the lower surface of the movable table 12, and flanges 23a and 23b are formed at both ends of the mounting plate 23, respectively. One end of drive cylinders 24a and 24b is attached to the flange portions 23a and 23b, respectively, and the drive cylinders 24a and 24b are arranged so that the cylinder axes of the drive cylinders 24a and 24b have a predetermined angle with respect to the vertical axis. Is done. This predetermined angle is, for example, 45 degrees.
[0012]
As illustrated, a spring brake 25 is attached to the other end of the drive cylinders 24a and 24b. The spring brake 25 is formed from a single spring member, and the central portion of the spring member is fixed to the mounting plate 23 by a bolt. The spring member extends downward from the fixed portion, and a portion for sandwiching the plate 21 is formed. That is, the spring member is formed with a curved portion 25a that is curved toward the plate 21, and the plate 21 is sandwiched by the curved portion 25a as described later. The spring member is attached to the other end of each of the drive cylinders 24a and 24b by bending both ends thereof outward. That is, both ends of the spring member are fixed to the cylinder shaft by bolts or the like.
[0013]
Here, in order to increase the friction coefficient between the plate 21 and the spring brake 25, the plate 21 and the spring member are formed of the same material, and for example, a material such as beryllium copper is used. Further, as the drive cylinders 24a and 24b, pneumatic cylinders that can sufficiently cope with a clean room or the like are used.
[0014]
Here, referring to FIG. 2 to FIG. 4, when air is not supplied to the drive cylinders 24a and 24b, both ends of the spring brake 25 are about to be narrowed inward by the elastic force. The bending force 25a of the spring brake 25 is also applied to the bending portion 25a. As a result, the plate 21 is sandwiched between the bending portions 25a, and the movable table 12 is stopped (see FIG. 2). .
[0015]
In the above-described state, when the movable table 12 is moved to a desired position (target position), air is first supplied to the drive cylinders 24a and 24b. As a result, as indicated by solid arrows in FIG. 3, the cylinder shafts of the drive cylinders 24a and 24b move upward, and both ends of the spring brake 25 are spread outward by the drive cylinders 24a and 24b. As a result, the curved portion 25a of the spring brake 25 is also spread outward as indicated by the solid arrow, and the pinching of the plate 21 by the spring brake 25 is released. That is, the spring brake 25 is opened (see FIG. 3). Thereafter, the movable table 12 is moved to the target position by the linear motor in the servo lock state.
[0016]
After moving the movable table 12 to the target position, the supply of air to the drive cylinders 24a and 24b is stopped. As a result, both ends of the spring brake 25 are narrowed inward by the elastic force, as indicated by solid arrows, and a force to narrow inward also acts on the curved portion 25a of the spring brake 25. As a result, the plate 21 is It is sandwiched between the curved portions 25a. That is, the spring brake 25 is closed, the plate 21 is sandwiched between the spring brakes 25, and the movable table 12 is completely stopped (see FIG. 4). Thereafter, the servo lock state is released, the servo is turned off, and the movable table 12 is completely set.
[0017]
【The invention's effect】
As described above, in the present invention, since the spring brake and the plate sandwiched between the spring brakes are formed of the same material, stick slip caused by friction of the guide system can be prevented, and the spring Since the servo mechanism by the linear motor is completely turned off when the brake is closed, there is no effect of servo system vibration, and the movable table can be set at the nano level. .
[0018]
Furthermore, in the present invention, since the spring member is driven by the pair of drive cylinders (air cylinders) and the movable table is braked by the spring members, the variation in the pressure by the air cylinder can be offset, and as a result, the accuracy is improved. There is also an effect that the movable table can be braked.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a linear disc brake according to the present invention.
FIG. 2 is a diagram illustrating a state in which a movable table is stopped by a linear disc brake.
FIG. 3 is a view for explaining release of a linear disc brake when moving a movable table.
FIG. 4 is a diagram for explaining the operation of the linear disc brake after moving the movable table.
FIG. 5 is a diagram showing a precision positioning stage using a linear motor.
[Explanation of symbols]
11 Linear motor 12 Table (stage)
13 Guide system 21 Plate 22 Fixing base 23 Mounting plate 24a, 24b Drive cylinder 25 Spring brake

Claims (2)

A plate that is used in a precision positioning stage in which a movable table is moved to a target position by a servo mechanism provided in a linear motor, and that extends along the moving direction of the movable table and is fixed to a fixed base on which the movable table is placed. A member, a spring brake having a central portion attached to the movable table and sandwiching the plate member to brake the movable table, and an air cylinder that drives and controls both ends of the spring brake, the plate member and the spring The brake is a linear disc brake that is formed of the same material as the brake, and is released from being sandwiched by the spring brake when air is supplied to the air cylinder. 2 air cylinders, the first and second air cylinders Are arranged such that their cylinder shafts have a predetermined angle with each other, and both ends of the spring brake are fixed to the first and second air cylinders, respectively, A linear disc brake characterized in that a pinching portion for pinching the plate member is formed between both end portions . 2. The method of controlling a linear disk brake for a precision positioning stage according to claim 1, wherein after the movable table is moved to the target position by the servo mechanism and the plate member is sandwiched by the spring brake, the servo A control method of a linear disc brake for a precision positioning stage, wherein the mechanism is turned off.

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