JP4618542B2 - Gripper device in a dolly for lifting and lowering conveying device - Google Patents

Description

  The present invention is arranged on a suspended lifting / lowering transportation vehicle carriage (hereinafter referred to as an OHT carriage) that travels in a suspended state on a rail, and a pair of fingers approach substantially horizontally. The present invention relates to a gripper device that enters under a flange of a carrier other than a cassette containing a wafer and supports the carrier in a suspended state, or for releasing the suspended state of the carrier by separating the pair of fingers substantially horizontally. Is.

For example, a cassette for storing and transporting semiconductor wafers to sequentially perform various processes (cleaning, CVD, etc.) in the semiconductor manufacturing process, as well as a carrier for transferring plate-like bodies to various processing units in liquid crystal manufacturing, FA, etc. In recent years, a suspension type lifting and lowering conveying device (hereinafter referred to as OHT) has become the mainstream as a conveying means from the viewpoint of improving productivity.
This OHT has a configuration in which the carrier is lifted and lowered at a predetermined position by a lifting mechanism of the OHT carriage, and the OHT carriage is transported in a suspended state to a rail disposed along a predetermined track. .

As a prior art related to the gripper device in the OHT cart according to each invention of the present application, there is the following Patent Document 1. The prior art of the gripper device in the OHT cart will be described with reference to Patent Document 1 as follows.
First, in Patent Document 1, an OHT carriage V is used to transport the carrier C as shown in FIGS. 1 and 2 showing the main part of the OHT. The OHT cart V travels in a suspended state on a traveling rail R attached to the ceiling, and a gripper device A is disposed below the OHT cart V. The gripper device A can be moved up and down by a lifter device (not shown) arranged on the OHT carriage V.

Next, as shown in FIGS. 4 and 5, the gripper device A is provided with a pair of fingers 4a and 4b for supporting the flange 5 of the carrier C from both sides. The pair of fingers 4a and 4b are fixed to the respective guide blocks 12a and 12b mounted on the guide rail 11 via linkage members. And with respect to a pair of connection block 21a, 21b provided corresponding to a pair of finger 4a, 4b, respectively, the screw which makes the spiral direction of a screw mutually differ with respect to a fixed direction on the both sides of an axial direction, respectively. The threaded portions 18a and 18b of the ball screw 18 formed with are screwed together. With this configuration, the pair of fingers 4a and 4b are moved toward or away from each other according to the rotation direction by rotating the ball screw 18. The ball screw 18 is rotated by a control motor 17.

By the way, during the period in which the carrier C rises into the OHT carriage V and is transported along the guide rail 11, power is supplied to the control motor 17 from the viewpoint of safety (preventing the fall of the carrier C due to malfunction). May be stopped. In such a case, the motor shaft 17a of the motor 17 is released from the electrical restriction, and thus the ball screw 18 is also in a free state. As a result, when the OHT carriage V travels on the traveling rail R, the distance between the pair of fingers 4a and 4b is gradually increased due to vibration transmitted to the OHT carriage through the wheels. There is a possibility that the screw 18 rotates.
When the control motor 17 is a motor with a brake, the motor shaft 17a is held in a stationary state even when power feeding is stopped. However, since the motor with a brake is larger than the normal control motor 17, and the installation space for the control motor in the gripper device A is limited, it is difficult to adopt the motor with a brake.

As a means for preventing such a carrier C dropping accident, the invention of Patent Document 1 includes a pair of fingers 4a and 4b which are approached and separated in a substantially horizontal manner as disclosed in FIGS. Regarding the gripper device that enters the holding portion 6 of the flange 5 of the C and supports the carrier C in a suspended state, the holding state of the carrier C by the fingers 4a and 4b is the power supply suspension state to the driving sources of the fingers 4a and 4b. However, a means for providing a means for maintaining the suction state with each other and preventing the carrier C from falling during the transportation is disclosed.
As specific means, air suction means, magnetic suction means, or the like is disclosed.
JP 2001-294390 A

As described in Patent Document 1 as the prior art, the flange portion 5 of the carrier C is held by the pair of fingers 4a and 4b provided in the OHT carriage V, and the carrier C is moved along the track. The vibration generated at this time is in a direction in which the ball screw 18 separates the pair of fingers 4a and 4b when the rotational force of the shaft of the drive motor 17 is lost while the power supply to the drive motor 17 is stopped. There is a possibility to rotate.
In such a situation, the engagement between the flange 5 of the carrier C and the fingers 4a and 4b is released, and the carrier falls from the OHT cart V, which causes a serious accident.

  On the other hand, each of the support portions of the pair of fingers 4a and 4b according to the aspect of the invention of Patent Document 1 also when the rotational force of the shaft of the drive motor 17 is lost while the power supply to the drive motor 17 is stopped. There is no possibility that the ball screw 18 rotates the pair of fingers 4a, 4b in the direction of separating the magnetic attraction force between the opposing end faces of each other and the separation of the pair of fingers 4a, 4b.

However, when the opposing end surfaces of the respective support portions of the fingers 4a and 4b that generate the magnetic attraction force come into contact with each other, impact vibration occurs when the end surfaces come into contact with each other. The female threaded portion that is screwed into and moves integrally with the fingers 4a and 4b is damaged.
Further, this develops into abnormal wear, and eventually the ball screw 18 falls into a non-rotatable locked state, and as a result, the ball screw 18 and the first female screw portion screwed with the ball screw 18 must be frequently replaced. Fall into.

  In addition, as in the invention according to claim 4 in Patent Document 1, the configuration in which a gap is provided between opposing surfaces that obtain magnetic attraction force that is displaced integrally with the pair of fingers 4a and 4b is opposed to magnetic attraction force generation. Damage due to collisions between surfaces is avoided. On the other hand, due to the presence of the large magnetoresistance gap, the force for preventing the pair of fingers 4a and 4b from being separated is weak, and the holding force of the carrier C by the fingers 4a and 4b cannot be obtained sufficiently.

  Accordingly, an object of the present invention is to provide a rail in which a pair of fingers provided on the OHT carriage are approached by a mechanism including a ball screw, engage with a flange portion of the carrier, and the carrier is moved up and down and further arranged on a track. When moving in the suspended state, the magnetic attraction surfaces provided corresponding to each of the pair of fingers are in contact with each other, and means for reducing the transmission of the impact vibration generated upon the contact to the ball screw is provided. This is to reduce the consumption of the drive mechanism.

Means and effects for solving the problems

In order to solve the above-mentioned problem, the gripper device in the OHT carriage according to claim 1 is attached so as to be able to move up and down on a suspended lifting and lowering conveyance apparatus carriage that travels in a suspended state on a rail attached to the ceiling. In a gripper device for supporting a suspended carrier by a pair of fingers that are horizontally approached and separated from each other, enter the lower part of the flange of the carrier, and are formed on each of the power receiving members of the pair of fingers. A pair of female screw portions that form spirals in opposite directions as a reference, a ball screw in which the pair of female screw portions are respectively screwed together to form male screws in opposite directions on both sides in the axial direction, and a motor its power and consists of a mechanism for transmitting to the ball screw, a rotary drive means of said pair of ball screws which finger the close-spaced by the same length, the A pair of stopper members fixed to the respective power receiving members of the pair of fingers, a main body portion and a head portion, the power receiving member being loosely fitted to the head side of the main body portion, and the stopper The member is fixed to the front end side of the main body with a screw so that the power receiving member and the stopper member are fixed to each other, and the opposing magnetic attraction surface provided between the pair of stopper members. A magnetic attraction means, and an impact mitigation means for mitigating an impact transmitted to the ball screw when the opposing magnetic attraction surfaces are in contact with each other , wherein the impact mitigation means includes the stopper member and the power receiving member. A first damping member made of a gel material interposed in the body portion of the fixing screw in between, and a gel material interposed in the body portion of the fixing screw between the stopper member and the head And Ranaru second damping member, and configured to have.

According to the first aspect of the present invention, the vibration shock that occurs when the opposing magnetic attraction surfaces come into contact with each other is alleviated, and between the ball screw and the female screw formed on the finger support portion that is screwed to the ball screw. The transmission of impact force to is also eased.
Thereby, it is possible to improve the durability of the ball screw and the female screw screwed into the ball screw.
Further, a pair of fingers engages with the flange of the carrier, and when the carrier is allowed to move up and down, the pair of magnetic attraction surfaces provided on the respective support portions of the pair of fingers maintain a contact state and are strong. A pair of fingers are not separated by magnetic attraction. Therefore, even if the OHT carriage is subjected to a vibration shock while traveling, the carrier is accurately supported by the finger, and there is no possibility of the carrier falling.
Furthermore, a first damping member made of a gel material is interposed in the main body portion of the fixing screw between the stopper member and the power receiving member. Therefore, the mechanism for reducing the impact force transmission between the ball screw and the female screw formed on the power receiving member of the finger screwed into the ball screw is simplified, and the tip of the mounting screw body is magnetic. Since it is fixed to the fixed part (stopper member) of the suction means and the damping member and finger support part are loosely fitted, there is an effect of mitigating impact force transmission and an effect of reducing assembly man-hours. Therefore, the cost of the gripper device can be reduced.
Further, a second damping member made of a gel material is also interposed in the main body portion of the fixing screw between the stopper member and the head portion. Therefore, even when a vibration impact occurs when the pair of opposing magnetic attraction surfaces of the magnetic attraction means abut, the impact transmitted to the ball screw and the female screw engaged with the ball screw is attenuated in any direction. Further, it is possible to further improve the durability of the ball screw and the female screw screwed into the ball screw.
Furthermore, since the first and second damping members are made of the gel material, the durability of the ball screw and the female screw can be improved. When such a gel material is used, damage to the ball screw and the female screw screwed into the ball screw is not recognized even in the contact test of the opposing magnetic attraction surfaces 5 million times.
Incidentally, in the durability test in a configuration in which no damping material is used, the ball screw and the female screw that is screwed to the ball screw are damaged in the contact test of the magnetic attraction surface 50 to 60,000 times.
Further, the gel material has a compression set of about 10% less than the case of using urethane rubber or natural rubber as the damping material, and the effect as the damping material is remarkable.

The gripper device in the OHT carriage according to claim 2 is the gripper device in the OHT carriage according to claim 1, wherein one of the opposing magnetic attraction surfaces is a magnetic pole surface of a permanent magnet and the other is an outer surface of the magnetic plate. Alternatively, the opposing magnetic attraction surfaces are magnetic pole surfaces of permanent magnets having different polarities.
According to the invention of claim 2, in addition to the effect of the invention of claim 1 of the citation source, the structure of the magnetic attraction means can be most easily obtained, and in particular, the pole faces facing each other have different polarities. In this case, a strong magnetic attractive force can be obtained.

The gripper device in the OHT carriage according to claim 3 is the gripper device in the OHT carriage according to claim 1 or 2, wherein the opposing magnetic attraction surfaces are in a non-contact state in a pair of finger approaching states. Control means for operating the rotation driving means until it can be joined by magnetic attraction force is provided.
According to the invention according to claim 3, in addition to the effect of the invention according to claim 1 or 2, the impact at the time of contact between the opposing magnetic attraction surfaces is based solely on the magnetic attraction force, There is no force by the rotational drive means, and in combination with means for reducing the impact transmitted to the ball screw when the opposing magnetic attraction surfaces come into contact with each other, the durability of the ball screw and the female screw screwed to the ball screw is further improved. be able to.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
First, the outline of the drawing will be described. FIG. 1 is a front view showing a main part configuration of an OHT cart according to the present invention, FIG. 2 is a perspective view showing the main part configuration of the present invention, and FIG. 3 is a part of FIG. It is an expanded sectional view.

As shown in FIG. 1, the OHT carriage V is suspended from a traveling rail R provided along a predetermined track on the ceiling. The OHT carriage V travels in the guide / drive unit 1 while being restricted by the travel rail R by travel wheels and guide wheels (not shown). In this case, the required power is a well-known means such as a driving motor provided on the traveling wheel, or a DC linear motor provided with a secondary side and a primary side on the rail R side and the OHT carriage V side, respectively. Obtained by. Reference numeral 2 denotes an elevating belt, which is provided four on the front, rear, left and right sides, and is configured to be able to expand and contract by a lifter device (not shown) provided in the OHT carriage V, and is configured to raise and lower the gripper device A. And this raising / lowering belt 2 is equipped with the electric wire for control of the gripper apparatus A inside.

The carrier C is, for example, a carrier main body 3 in which a predetermined number of wafers before and after various types of processing are accommodated, and a pair of fingers 4a and 4b attached to the upper side of the carrier main body 3 as main components of the gripper device A. It is comprised from the substantially rectangular flange 5 supported by lowering. The flange 5 is mounted on the upper surface of the carrier main body 3 so as to be substantially horizontal on the upper surface of the flange holding unit 6 mounted substantially at the center in plan view. The flange holding portion 6 is for forming a gap for allowing the pair of fingers 4 a and 4 b to enter between the carrier body 3 and the flange 5. The flange 5 and the flange holding portion 6 are attached with substantially the same axial center.

Next, the gripper device A will be described with reference to FIG. 2 in particular with regard to a preferred specific configuration of the pair of fingers 4a and 4b disclosed in FIG. In FIG. 2, 4ax and 4bx are support portions for a pair of fingers 4a and 4b, respectively, which are integrally fixed to the outer ends of the fingers 4a and 4b and extend upward. Reference numerals 7a and 7b denote frames corresponding to the fingers 4a and 4b, respectively, and the outer ends of the frames are integrally fixed at predetermined positions on the inner surfaces of the finger support portions 4ax and 4bx, respectively.

The frames 7a and 7b are supported by a guide mechanism (not shown) so as to be horizontally movable in the longitudinal direction (see, for example, the peripheral configuration including the guide rail 11 and the guide blocks 12a and 12b in FIG. 5 of Patent Document 1). ). 8a and 8b are stopper members, which are fixed to the inner ends of the frames 7a and 7b by fixing screws 9a and 9b, respectively. 10a and 10b are permanent magnets, which are integrally fixed to the stopper members 8a and 8b, respectively. Opposing surfaces have different polarities, and magnetic attraction force increases as the distance between the opposing magnetic pole surfaces approaches, When the magnetic pole faces come into contact with each other, they are not separated unless a corresponding external force is applied.

Next, referring to FIG. 3 as well, the configuration of the main part of each invention of the present application will be described. Reference numeral 11 denotes a ball screw, which has a spiral direction with respect to a specific direction opposite to the central portion in the longitudinal direction, and is formed until male screws 11a and 11b having an equal pitch reach the support portions at both ends. 12a and 12b are power receiving members, and female screws 12ax and 12bx (only 12bx in the drawing) are formed to be engaged with the male screws 11a and 11b of the ball screw 11, respectively. It is assumed that it is initially set so as to be screwed into the male screws 11a and 11b located at an equal distance from the center of the direction. The pair of power receiving members 12a and 12b are fixed to the stopper members 8a and 8b by an appropriate number, for example, two fixing screws 14a and 14b via the first damping members 13a and 13b, respectively. Is done.

At this time, with respect to the fixing screws 14a and 14b, the main body portions 14ax and 14bx (only 14bx in the drawing) are fixed to the stopper members 8a and 8b by screwing, and the power receiving members 12a and 12b are not fixed. It is loosely fitted. Reference numerals 15a and 15b denote second damping members which are interposed between the heads of the fixing screws 14a and 14b and the power receiving members 12a and 12b, respectively. Even if the second damping members 15a and 15b are not provided, it is considered that the action of the first damping members 13a and 13b is sufficient.
However, the impact generated when the opposing magnetic pole surfaces of the permanent magnets 10a and 10b come into contact with each other may be considerably large, and the second damping members 15a and 15b are screwed into the male screws 11a and 11b of the ball screw 11 and the screws. Shock transmitted to the threaded portion of the female screws 12ax and 12bx formed on the power receiving members 12a and 12b to be joined (particularly, the opposing magnetic pole surfaces of the permanent magnets 10a and 10b vibrate in the direction opposite to the impact direction at the moment of contact. It helps to further increase the impact damping effect.

The first damping members 13a and 13b and the second damping members 15a and 15b are made of an elastic material such as a rubber material, a urethane material, or a gel material. In particular, a gel material having the smallest compression set is used. It is desirable to use it.
Incidentally, in the opening / closing durability test of the fingers 4a and 4b using the gel material as the first damping member, the male screws 11a and 11b of the ball screw 11 that are most easily damaged by impact in the opening and closing operation of 5 million times, and the screws The state which confirms the damage of the internal thread 12ax and 12bx formed in the power receiving member 12a and 12b to join is not discovered.

Next, a support / drive mechanism for the ball screw 11 will be described with reference to FIG. In FIG. 2, reference numerals 16a and 16b denote support plates which rotatably support both end portions of the ball screw 11. Reference numeral 17 denotes a substrate, which fixes the support plates 16a and 16b at predetermined positions, and is provided with a motor 18 for driving the ball screw 11, and is suspended from the OHT carriage V by four elevating belts 2a, 2a, 2b and 2b. Is done. The rotating shaft of the motor 18 is connected to the input side of the universal joint 19. A gear 20 is provided on the output side of the universal joint 19. Reference numeral 21 denotes a gear which meshes with the gear 20 and receives power from the motor 18 and is fixed to one end of the ball screw 11 and rotates integrally with the ball screw 11.

Next, the operation of the configuration disclosed in FIGS. 1 to 3 will be described.
First, in FIG. 1, when the OHT carriage V detects the position of the carrier body 3 based on known optical means (not shown), the elevating belt 2 is drawn out and the gripper device A is lowered. Next, the fingers 4 a and 4 b installed in the gripper device A enter both sides of the flange holding portion 6, and a pair of fingers 4 a and 4 b get ready to raise the carrier body 3 into the OHT carriage V. After that, as the elevating belt 2 is wound into the OHT carriage V, the carrier body 3 that has been raised into the OHT carriage V travels in a suspended state on a rail R disposed along a predetermined track. Then, it reaches a predetermined place where necessary processing is performed. At this time, the OHT carriage stops traveling, the lifting belt 2 is again fed out from the OHT carriage V, and the carrier body 3 is lowered to a predetermined location. Thereafter, the pair of fingers 4a and 4b are subjected to a separation action, and the engagement with the flange holding portion 6 provided in the carrier body 3 is released. As a result, the carrier body 3 is released from the holding state in the OHT carriage V. .

The above operation is an outline of the operation of the entire application target device of each invention of the present application, and the operation of FIGS. 2 and 3 (cross-sectional view of the main part of FIG. 2) showing the configuration according to each invention of the present application will be described.
FIG. 2 shows a state in which the fingers 4a and 4b are close to each other and the opposing magnetic pole surfaces of the permanent magnets 10a and 10b are just before contact.
First, when approaching or separating the pair of fingers 4a and 4b, as the ball screw 11 rotates, the power receiving members 12a and 12b move from the center in the longitudinal direction of the ball screw to the left and right at equal distances. As a result, the pair of fingers 4a and 4b also move the same distance. In this case, the power of the motor is transmitted to the ball screw 11 through the universal joint 19 and the gears 20 and 21 in this order.

In this way, the pair of fingers 4a and 4b are subjected to the approach and separation control, and the limit of the approach and separation is precisely controlled using a pulse motor for the motor 18, for example. In the case where precise control is not required, the number of rotations of the motor 18 is controlled according to the required moving distance of the pair of fingers 4a and 4b, or the position of the magnetic pole surface of the permanent magnet 10a is optically determined, for example. This can be dealt with by detecting and controlling to stop the power supply of the motor 18 by this detection signal.

By the way, if a gap exists between the magnetic pole faces of the permanent magnets 10a and 10b fixed to the pair of stopper members 8a and 8b, the magnetic attractive force is reduced. Therefore, in a free state where there is no power supply to the motor 18, the pair of fingers 4a and 4b are separated in a direction away from the carrier C (see FIG. 1) held by the pair of fingers 4a and 4b. There is a possibility of causing a fall accident of the carrier C if it operates in the above manner.
In order to prevent such a state, in the inventions of the present application, in a state where the pair of fingers 4a and 4b hold the carrier C in the approaching state, the opposing surfaces of the pair of permanent magnets 10a and 10b are brought into contact with each other.

Now, when the opposing surfaces of the pair of permanent magnets 10a and 10b come into contact with each other in the process in which the ball screw 11 drives the pair of power receiving members 12a and 12b closer to each other by supplying electric power to the motor 18. Vibration impact force is generated. The impact force is first attenuated by the pair of first damping members 13a and 13b, and the female screws 12ax formed on the power receiving members 12a and 12b respectively engaged with the male screws 11a and 11b formed on the ball screw 11. The influence on 12bx and the screwing portion is mitigated, and the durability of the ball screw 11 and the power receiving members 12a and 12b can be improved.

On the other hand, although the opposed surfaces of the pair of permanent magnets 10a and 10b are weaker than the instantaneous impact, an impact in the opposite direction may occur as a vibration impact. The impact in the opposite direction is attenuated by the second damping members 15a and 15b, and the female screws 12ax and 12bx formed on the power receiving members 12a and 12b respectively screwed with the male screws 11a and 11b formed on the ball screw 11 as described above. Thus, the influence on the screwing portion is alleviated, and the durability of the ball screw 11 and the power receiving members 12a and 12b can be improved.

Note that the vibration impact generated when the magnetic pole surfaces of the permanent magnets 10a and 10b are brought into contact with each other is such that the distance between the opposing surfaces of the pair of permanent magnets 10a and 10b can be brought into contact only with the mutual magnetic attraction force. Further attenuation can be achieved by rotating the ball screw 11 by the driving force of the motor 18 to the range before contact.
At this time, the permanent magnets 10a and 10b move by a corresponding distance from the disappearance of the power of the motor 18 until the opposing magnetic pole faces come into contact with each other only by the magnetic attractive force. This moving distance is set as the clearance of the machine elements from the motor 18 to the permanent magnets 10a and 10b, and the practical optimum distance is obtained empirically.

One of the pair of permanent magnets 10a and 10b as means for generating a magnetic attractive force between the opposing surfaces may be a magnetic body.

  The damping members 15a and 15b need not be provided when it can be determined that the impact at the time of contact between the magnetic pole faces is not particularly large.

It is a front view which shows the principal part structure of the cart for OHT which concerns on this invention. It is a perspective view which shows the principal part structure of this invention. It is a partially expanded sectional view of FIG.

Explanation of symbols

A. Gripper device R.P. Rail V. 2. Cart for OHT Carriers 4a, 4b. Finger 5. Flange 10a, 10b. Permanent magnet 11. Ball screws 11a, 11b. Male screw portions 12a, 12b. The power receiving members 12ax, 12bx. Female thread 13a, 13b. 1st damping material 15a, 15b. Second damping material 18. motor

Claims (3)

A pair of fingers that can be moved up and down on a trolley for a lifting and lowering transporting device that travels in a suspended state on a rail attached to the ceiling, and that is horizontally approached and separated, enter under the flange of the carrier, In the gripper device for hanging and supporting the carrier,
A pair of internal thread portions formed in each power receiving member of the pair of fingers and having a spiral shape opposite to each other with respect to a certain direction;
A ball screw in which the pair of female screw portions are respectively screwed to form a male screw having a spiral shape opposite to each other on both sides in the axial direction;
A rotation driving means for the ball screw, which comprises a motor and a mechanism for transmitting the power of the motor to the ball screw;
A pair of stopper members each fixed to each power receiving member of the pair of fingers;
The power receiving member is loosely fitted to the head side of the main body, and the distal end side of the main body is screwed and fixed to the stopper member. Fixing screws for respectively fixing the receiving member and the stopper member;
Magnetic attraction means provided between the pair of stopper members and having opposing magnetic attraction surfaces;
An impact mitigating means for mitigating an impact transmitted to the ball screw at the time of contact between the opposing magnetic attraction surfaces;
Equipped with a,
The impact mitigating means is
A first damping member made of a gel material interposed in a main body portion of the fixing screw between the stopper member and the power receiving member;
A second damping member made of a gel material interposed in a main body portion of the fixing screw between the stopper member and the head portion;
Gripper device in suspended, lifting transfer apparatus carriage which is a structure having.   The opposing magnetic attraction surface is one of a magnetic pole surface of a permanent magnet and the other is an outer surface of a magnetic plate, or a magnetic pole surface of a permanent magnet having a different polarity. A gripper device in a cart for a suspended lifting and lowering conveying device. Control means for operating the rotation driving means until the opposing magnetic attraction surfaces are in a non-contact state and can be joined by magnetic attraction force in the pair of fingers approaching state;
The gripper device according to claim 1 or 2, wherein the gripper device is a cart for a suspension type lifting device.

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