JP2008160937A - Carrying mechanism with brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carrying mechanism with brake which can obtain a large braking force with less number of part items and small structure without installing an independent external brake mechanism. <P>SOLUTION: The carrying mechanism with brake includes: a guide rail arranged at a pedestal; a moving guide member which is mounted to the guide rail, and travels and moves along the guide rail; a base arranged at the moving guide member; a fixed magnet rail arranged at the pedestal; a large number of travel thrusting magnets which are arranged on both front and rear surfaces of the fixed magnet rail, and aligned at intervals in the longitudinal direction of the fixed magnet rail; a motor coil which is arranged at the base, and creates a traveling thrust by a magnetic action with the travel thrusting magnets; and a brake means which holds the fixed magnet rail. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes a filter unit for ensuring cleanliness in the apparatus, a load port for storing a working wafer, an alignment mechanism for correcting the wafer position, and a transfer with a brake of a wafer transfer apparatus that travels by a linear motor. Regarding the mechanism.

  2. Description of the Related Art Conventionally, in a transport mechanism used in a semiconductor manufacturing apparatus or the like, an elevating mechanism that combines a ball screw and a motor is often used for a vertical traveling shaft on which a robot and a mount are mounted.

  One of the reasons is that it is inexpensive and has a great deal of use, and that the braking mechanism can be realized simply.

  However, the ball screw, on the other hand, has the drawbacks that the moving stroke cannot be made very long due to the structure, the speed cannot be increased, and dust is generated from the contact portion between the ball screw and the bearing.

  There is a linear motor as an alternative mechanism of the traveling shaft. Unlike the ball screw, the linear motor has a structure in which the fixed magnet rail that generates thrust and the motor coil are not in contact with each other, and dust is hardly generated. In addition, a long moving stroke is possible at a higher speed than a ball screw.

  From the above points, the linear motor has more advantages than the ball screw and is suitable for the travel axis. However, when the linear motor is used for the vertical axis, a means for holding the linear motor in the moved position is required. .

  In the power supply state, no special means is required because the linear motor is held on the fixed magnet rail by the excitation force of the motor coil.

  However, when the power supply of the device is cut off or when the power supply is cut off due to a failure, the excitation force of the motor coil is lost and the motor coil falls due to the influence of the load and its own weight.

  For this reason, conventionally, a brake mechanism that presses the frictional objects together using a force such as an air cylinder or hydraulic pressure is provided outside, and braking is performed using the frictional force.

  However, these brake mechanisms require a larger braking force as the load and the weight of the brakes increase, and the brake structure itself increases accordingly. was there.

  For example, in order to prevent magnetic attraction between the stator having the N and S magnetic poles alternately arranged on the fixed magnet rail and the stator as in the prior art disclosed in Japanese Patent Application Laid-Open No. 2002-186243 (Patent Document 1). A holding brake is also added to a linear motor that generates traveling thrust with a magnetic attractive force that acts between the stator and the mover. Therefore, it is necessary to provide means such as an external brake in order to apply to the transport mechanism of the vertical traveling shaft.

  Further, the prior art disclosed in Japanese Patent Laid-Open No. 10-112971 (Patent Document 2) and Japanese Patent Laid-Open No. 2003-301872 (Patent Document 3) utilizes the magnetic attractive force of a fixed magnet rail for traveling thrust. The brake mechanism has been released.

JP 2002-186243 A JP-A-10-112971 Japanese Patent Laid-Open No. 2003-301872

  An object of this invention is to provide the conveyance mechanism with a brake which can obtain big braking force with a simple structure in view of said problem.

  Another object of the present invention is to provide a transport mechanism with a brake having a compact and space-saving structure by using a magnetic attraction force of a fixed magnet rail without providing an external brake mechanism. And

  The present invention is based on the magnetic action of a fixed magnet rail, a large number of traveling thrust magnets arranged on the front and back surfaces of the fixed magnet rail and arranged at intervals in the longitudinal direction of the fixed magnet rail, and the traveling thrust magnet. The present invention is characterized by having a motor coil that generates a driving thrust and a brake means that clamps a fixed magnet rail from both sides.

  More specifically, the brake means has a pair of brake plates formed of a metal including a steel plate that faces and faces both surfaces of the fixed magnet rail.

  According to the present invention, since the fixed magnet rail is clamped from both sides by the brake means, it is possible to provide a transport mechanism with a brake that can obtain a large braking force with a simple structure.

  In addition, a pair of brake plates made of metal, including steel plates, are brakes that are strongly attracted by the magnetic attractive force of the fixed magnet rail, so there is no need to provide an external brake mechanism, and a compact and space-saving structure A brake-equipped transport mechanism can be provided.

  Embodiments of the present invention will be described with reference to the drawings.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  As shown in FIGS. 1 and 2, a linear motor is formed by the fixed magnet rail 6 and the motor coil 3. This linear motor is used in a transport mechanism for transporting a wafer made by a semiconductor manufacturing apparatus, in which fixed magnet rails 6 serving as traveling axes are arranged vertically, horizontally, or inclined.

  When a linear motor is applied to the vertical travel axis transport mechanism, a braking force is obtained by servo control of the motor controller when power is supplied, and the current position can be held while supporting the weight of the load or its own weight.

  However, the exciting current of the movable motor coil 3 is cut off when the power supply is cut off or the power supply system fails. For this reason, since the magnetic attraction force between the fixed magnet rail 6 is lost and the braking force is lost, it is necessary to provide a brake.

  As shown, the fixed magnet rail 6, which is a vertical traveling axis, is fixedly supported on the gantry 7.

  The gantry 7 has a guide rail 5 extending vertically. The movement guide member 4 travels along the guide rail 5. The base 1 is fixedly supported by the movement guide member 4. A robot is mounted on the base 1. The robot is placed on the base 1 and moves up and down in the vertical direction.

  The movement guide member 4 is supported by the guide rail 5 so as to be able to travel and move using a ball bearing 30 shown in FIG. The moving guide member 4 is detached from the guide rail 5 by the two ball bearings 30 fitted in the side groove 31 of the guide rail 5.

  The backlash in the left-right direction of the moving guide member 4 is suppressed by one ball bearing 30 fitted in the front end groove 42 of the guide rail 5.

  The fixed magnet rail 6 extends in parallel with the guide rail 5 and is placed in a state of floating from the gantry except where both ends are supported by the gantry 7.

  The motor coil 3 is sandwiched from both sides in order to use the magnetic attractive force of the traveling thrust magnets 13 provided on both the front and back surfaces of the fixed magnet rail 6, and is not contacted with the fixed magnet rail 6 at a certain distance. It is attached and fixed to the base 1 so as to run while keeping

  The brake means includes a brake plate 2, a brake retainer 9, a rotation fulcrum 50, a brake spring 8, an electromagnet 10, and a brake plate side friction member 12.

  The fixed magnet rail 6 is sandwiched from both sides by a metal brake plate 2 including a steel plate when the power is shut off or the power system fails.

  The pair of brake retainers 9 that support the pair of brake plates 2 and are pivotally supported via the pivot fulcrum 50 are brake springs that urge the clamping force to clamp the fixed magnet rail 6 from both sides. 8 and an electromagnet 10 that operates to release the holding means of the brake against the holding force of the brake spring 8.

  Since the brake means is configured in such a configuration, the brake means operates as follows.

  As a series of flow of the brake presser 9 from the state where the apparatus power supply is shut off and the holding brake mechanism is operating, the motor coil 3 is excited after the power supply is started, and the weight of the robot and the platform 7 mounted on the base 1 is reduced. The brake is released when sufficient thrust is obtained.

  That is, by applying an exciting current to the electromagnetic coil 10 at the time of releasing the brake, one end of the brake retainer 9 is attracted, and the brake plate 2 magnetically attracted to the traveling thrust magnet 13 is separated from the fixed magnet rail 6.

  As a result, the frictional force of the fixed magnet rail side friction member 11 and the brake side friction member 12 is lost (unsolved).

  Conversely, when the power supply is cut off or the power supply system fails, the excitation current of the motor coil 3 is cut off, and the thrust that can hold the load and its own weight disappears, and at the same time, the excitation current of the electromagnetic coil 10 is cut off.

  At the same time, the brake plate 2 instantly starts to pinch the fixed magnet rail 6 by the pulling force of the brake spring 8, and the magnetic attraction of the traveling thrust magnet 13 acts to obtain a large responsive braking force. The robot is stopped and held at the position where the power is cut off without moving naturally.

  The excitation current of the motor coil 3 and the electromagnetic coil 10 is controlled by the motor controller together with the position control in the vertical traveling direction.

  As shown in FIG. 2, in the center of the fixed magnet rail 6, a traveling thrust magnet 13 made of rare earth neodymium or the like having high magnetic properties is arranged alternately with N and S poles in order to obtain sufficient traveling thrust. ing.

  The fixed magnet rail side friction member 11 is laid in parallel with the fixed magnet rail 6 at a position where both sides of the traveling thrust magnet 13 do not interfere.

  As described above, at the time of braking in vertical running such as power interruption, the brake plate side friction member 12 provided on the brake plate 2 sandwiches the fixed magnet rail side friction member 11 with the brake press 9 by the magnetic attraction of the magnet 6, Since the friction members are pressed against each other and a frictional force is generated, a large braking force can be obtained with a simple structure.

  The friction member also serves as a cushioning material for preventing the traveling thrust magnet 13 from being damaged by an impact generated when the brake plate 2 is instantaneously sandwiched by the pulling force of the spring 8 and the attractive force of the traveling thrust magnet 13.

  When cork is used as the friction member, a good buffering effect can be expected and generation of sound can be suppressed.

  The brake mechanism, which is the brake means, is configured such that each friction member is sandwiched between the brake retainer 9 on one side via the rotation fulcrum 50, but the traveling thrust magnet 13 magnetically attracts the center of the brake plate 2. The frictional force is generated evenly on the left and right friction members.

  On the other hand, in the holding brake release operation at the time of power supply, the electromagnetic coil 10 pulls one end of the brake retainer 9 with a strong force in order to separate the brake plate 2 attracted by the traveling thrust magnet 13 and lose the braking force. It is necessary to attract.

  In that case, a plurality of electromagnetic coils 10 may be provided.

  In addition, since the brake means sandwiches both the front and back surfaces of the fixed magnet rail 6 with the two brake plates 2, an excessive force is not applied to the ball bearing 30 shown in FIG.

  That is, in the case of the brake mechanism that is pressed from one side shown in Patent Document 2 described above, the pressing force acts on the ball bearing of the guide rail along with the magnetic attraction of the traveling thrust magnet.

  In the case of the present embodiment, since the fixed magnet rail 6 is clamped from both sides, such a pressing force does not act, and an excessive force is not applied to the ball bearing 30. Wear of the ball bearing 30 and the side groove 31 of the guide rail 5 hardly occurs, and high-precision traveling is maintained.

  Next, the embodiment shown in FIG. 3 will be described.

  According to this embodiment, the maximum braking force can be obtained immediately after the start of the braking operation, as compared with FIGS.

  That is, the brake mechanism of the transport mechanism shown in FIGS. 1 and 2 described above has a structure in which the friction members are sandwiched by the brake press 9 with one side as a fulcrum to generate a frictional force.

  For this reason, the brake plate 2 first presses the friction plate 11 on one side and the friction member 12 on the one side provided near the fulcrum so as to draw a circular orbit so as to draw a circular orbit when starting the clamping operation. To do.

  Ultimately, since the traveling thrust magnet 13 magnetically attracts the center of the brake plate 2, the frictional force is generated evenly on the left and right friction members, but the braking force immediately after the start of the operation is halved. Therefore, there is a problem that the maximum braking force cannot be generated at the moment when the apparatus power supply is shut off.

  FIG. 3 provided with means for solving the problem is based on a structure in which the brake mechanism of the transport mechanism in FIGS. 1 and 2 is sandwiched between fulcrums on one side, and the brake plate 2 provided in parallel on both the front and back surfaces of the magnet rail 6. The structure is improved by pressing the friction members together.

  In other words, the brake mechanism includes a plurality of brake springs 8 provided on the back side of the pair of brake plates 2 so as to press the pair of brake plates 2 against the fixed magnet rail 6, and a pair of brake plates via the brake springs 8. 2 and a pair of brake pressers 9 placed opposite to each other, and an electromagnet 10 that operates to separate the pair of brake plates 2 pressed against the fixed magnet rail 6 against the brake spring 8 from the fixed magnet rail 6. It has the composition which has.

  In order to release the holding brake when power is supplied, the brake plate 2 is pulled up by the magnetic attractive force generated by the excitation of the electromagnet 10 and held at a position where the frictional force is lost.

  When the power supply is cut off or the power supply system fails, the electromagnet 10 is de-energized and loses its attractive force. At the same time, the extension force of the brake spring 8 works, and the brake plate 2 starts to be sandwiched with the fixed magnet rail 6 in parallel.

  Further, the magnetic attraction force of the traveling thrust magnet 13 is also applied so that the left and right friction members are pressed against each other evenly, so that the maximum braking force can be obtained immediately after the start of the braking operation.

  FIG. 4 is a timing diagram of the brake control and shows the relationship between the power supply voltage and the braking force.

  When the power supply of the device is cut off or breaks down during the operation of the transport mechanism where the braking force is not working at the power supply voltage of 100%, the power supply voltage is usually applied to the energy (charge) stored in the electrolytic capacitor inside the power supply and the motor brake. The voltage drops slowly due to the regenerative energy (induced voltage) generated when it is applied.

  When the power supply voltage drops to about 70%, the electromagnetic coil 10 loses the exciting current and loses the force to hold the brake plate 2, and starts braking by the extension force of the spring 8 (part a).

  Although the braking force is small at the time point “a”, this operation is necessary because it acts to increase the response of the brake and triggers the friction member to start.

  Thereafter, when the distance between the brake plate 2 and the magnet rail 6 approaches within a certain value, the stress pressing the friction members generated by the magnetic attraction force of the magnet 13 is added to the extension force of the spring 8 and suddenly increases the braking force. Becomes larger (part b).

  At the timing when the power supply voltage drops to 50% or less, the brake plate 2 and the magnet rail 6 are in a magnetically attracted state and maintain a complete braking state (section c).

  In addition, since the power supply voltage rises in a short time at the start of power supply, the exciting current of the electromagnetic coil 10 starts to flow when it rises to about 80%, and the operation of attracting the brake plate 2 is started (part d).

  At the timing of completely separating the brake plate 2 magnetically attracted to the magnet rail 6, the power supply voltage has already increased to 100%, so that the motor coil 3 has obtained a thrust that can sufficiently hold the gantry and its own weight. At this point, the holding brake is released (section e).

  FIG. 5 is a block diagram of the controller.

  The controller shown in the block diagram performs control at the timing shown in FIG.

  The AC detection unit f constantly monitors the power supply voltage, determines the brake operation (70%) / release (80%) voltage, and sends a detection signal to the calculation unit g.

  In order to determine whether the detection signal is a transient signal such as noise or a normal detection signal, the calculation unit g performs A / D conversion on the detection signal and performs filter and average processing. In the case of a normal detection signal, the excitation current control unit h controls the excitation current of the electromagnetic coil to perform excitation / cutoff processing.

  In the brake i, the brake operation of the transport mechanism is performed at the timing shown in FIG. 4 in accordance with the excitation / de-excitation operation of the electromagnetic coil.

  An example in which the above-described transfer mechanism with brake is applied to a semiconductor wafer transfer apparatus will be described.

  When the power is shut off or the power supply system fails, it is necessary to ensure the safety of the worker by operating the brake instantaneously and applying an interlock so that there is no danger of hitting an extension such as an underlay of the robot or an arm.

  Further, when the wafer is attracted to the robot hand, there is a risk that the brake operation is delayed and the peripheral device is touched and the wafer is damaged.

  This embodiment is particularly effective for a configuration having a fixed magnet rail (vertical traveling axis) such as a robot that requires a large braking force instantaneously when the power is shut off. The fixed magnet rail (vertical traveling axis) in this case refers to a traveling axis that conveys in a range of 90 ° ± 5 ° at a general vertical angle.

  In addition, the demand for high cleanliness, high accuracy, and miniaturization is expected to increase in the future for semiconductor manufacturing equipment stages, etc., so there is a limit to the conventional vertical axis transport mechanism using a ball screw. is there.

  This embodiment realizes elimination of the external brake mechanism, which is a problem when the transport mechanism is shifted to a linear motor, and can be applied to other semiconductor manufacturing apparatuses.

  The linear motor in this embodiment has a structure in which a fixed magnet rail is sandwiched between motor coils to generate running thrust using the magnetic attraction force on both the front and back surfaces. It will be in a state to be.

  According to this embodiment, the friction member provided on both surfaces of the fixed magnet rail based on the structure described above is sandwiched from both sides by the friction member of the brake mechanism and braked, so that the fixed magnet rail is caused by the stress of the friction member from one side. There is no problem of warping and a large braking force can be obtained.

  Further, since the brake mechanism is integrated with the fixed magnet rail, space saving can be realized with an inexpensive structure with fewer components compared to the case where an independent brake structure (external brake mechanism) is provided outside.

Sectional drawing concerning the Example of this invention, and having looked at the traveling direction of the fixed magnet rail (vertical traveling shaft) in front. The perspective view of a linear motor and a brake mechanism concerning the Example of this invention. Sectional drawing which concerns on the other Example of this invention, and looked at the traveling direction of the fixed magnet rail (vertical traveling shaft) toward this side. FIG. 4 is a timing chart of brake control according to the embodiment of the present invention. FIG. 3 is a block diagram of a controller according to an embodiment of the present invention. The figure which concerns on the Example of this invention, and showed the relationship between a guide rail, a movement guide member, and a ball bearing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Base, 2 ... Brake board, 3 ... Motor coil, 4 ... Movement guide member, 5 ... Guide rail, 6 ... Fixed magnet rail, 7 ... Mount, 8 ... Flake spring, 9 ... Brake press, 10 ... Electromagnet, 11 ... Magnet rail side friction member, 12 ... brake plate side friction member, 13 ... magnet for running thrust.

Claims (10)

  A traveling thrust is generated by the magnetic action of the traveling thrust magnet, which is provided on both the fixed magnet rail and the front and back surfaces of the stationary magnet rail, and is arranged at intervals in the longitudinal direction of the stationary magnet rail. A transport mechanism with a brake, comprising: a motor coil; and a brake means for holding the fixed magnet rail from both sides.   A guide rail provided on the gantry, a movement guide member attached to the guide rail and traveling along the guide rail, a base provided on the movement guide member, a fixed magnet rail provided on the gantry, Provided on both the front and back surfaces of the fixed magnet rail, a number of traveling thrust magnets arranged at intervals in the longitudinal direction of the fixed magnet rail, and provided on the base, the traveling thrust is generated by the magnetic action of the traveling thrust magnet. A conveying mechanism with a brake, characterized by having a motor coil that raises and a brake means that clamps a fixed magnet rail from both sides. In the conveyance mechanism with a brake according to claim 1 or 2,
The brake means includes a pair of brake plates formed of a metal including a steel plate that faces and faces both surfaces of the fixed magnet rail. In the conveyance mechanism with a brake according to claim 3,
It has a magnet rail side friction member provided on both surfaces so as to extend along the longitudinal direction of the fixed magnet rail, and a brake plate side friction member provided on the brake plate and in sliding contact with the magnet rail side friction member. A transport mechanism with a brake. In the conveyance mechanism with a brake according to claim 3,
A pair of brake retainers that support the pair of brake plates and are rotatably supported via a rotation fulcrum, and a brake spring that urges a clamping force by which the brake means clamps the fixed magnet rail from both sides And an electromagnet that operates to release the holding of the brake means against the holding force of the brake spring. In the conveyance mechanism with a brake according to claim 3,
A brake spring provided on the back side of the pair of brake plates so as to press the pair of brake plates against the fixed magnet rail, and a pair of brakes placed so as to face the pair of brake plates via the brake spring A transport mechanism with a brake, comprising: a presser; and an electromagnet that operates to separate the pair of brake plates pressed against the fixed magnet rail against the brake spring from the fixed magnet rail. In the conveyance mechanism with a brake according to claim 1 or 2,
A transport mechanism with a brake, wherein the fixed magnet rail is provided vertically. In the conveyance mechanism with a brake according to claim 1 or 2,
The transport mechanism with a brake, wherein the traveling thrust magnet is a permanent magnet containing a rare earth.   A traveling thrust is generated by the magnetic action of the stationary thrusting magnet and the traveling thrusting magnets that are provided on both the front and back surfaces of the stationary traveling rail and are arranged at intervals in the longitudinal direction of the stationary traveling rail. A motor coil, a brake unit that clamps the fixed magnet rail from both sides, an electromagnet that operates so as to release the clamping of the brake unit, and an excitation current control unit that controls the excitation current of the motor coil and the electromagnet. A transport mechanism with a brake. In a wafer transfer apparatus having a filter unit for ensuring cleanliness in the apparatus, a load port for storing a working wafer, and an alignment mechanism for correcting the wafer position,
A guide rail provided on the gantry, a movement guide member attached to the guide rail and traveling along the guide rail, a base provided on the movement guide member, a fixed magnet rail provided on the gantry, A plurality of traveling thrust magnets arranged on the front and back surfaces of the fixed magnet rail and arranged at intervals in the longitudinal direction of the fixed magnet rail, and provided on the base, the traveling thrust is generated by the magnetic action of the traveling thrust magnet. Controls the motor coil that wakes up, the robot provided on the base, the brake means that clamps the fixed magnet rail from both sides, the electromagnet that operates to release the brake means, the excitation current of the motor coil and the electromagnet A conveyance mechanism with a brake, characterized by having an exciting current control unit.

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