JP2005194009A - Suspension type conveying carriage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension type conveying carriage capable of suppressing shaking following the rotation moment of a gripped object and vertical and lateral shaking. <P>SOLUTION: The suspension type conveying carriage comprises a travel section 3 travelling on a travel rail, a gripping mechanism section 2 that is disposed in the travel section 3, grips a FOUP gripped section 12 formed on the upper surface of an FOUP 1, and can lift in a suspension state, and buffer members 18a, 18b, 18c and 18d fixed to the gripping mechanism section 2 so as to pressure-contact with a predetermined position of the upper surface of the FOUP 1 different from the forming positions of the FOUP gripped section 12 when the FOUP 1 is raised by the gripping mechanism section 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a suspension type transport carriage in a transport system such as a semiconductor manufacturing process.

  For example, in a semiconductor manufacturing process, a silicon wafer is stored in a clean storage box that is not affected by dust, such as FOUP, and is transferred between manufacturing apparatuses. As the transport means, an unmanned transport system using a carriage traveling on a track such as OHT (Over Head Hoist Transport) or OHS (Over Head Shuttle) has become mainstream.

  Conventionally, as shown in FIG. 8, the traveling rail 6, which is a track suspended from the ceiling, and the protrusion 12 of the FOUP 1 that is the object to be gripped are uniformly supported by the entire contact surface of the finger 16 of the gripping mechanism 2. An OHT transport system including an OHT transport cart 5 that transports the FOUP 1 between processes by traveling on the travel rail 6 in the arrow direction A by the travel unit 3 housed in the travel rail 6 is known. Yes.

  In the above OHT conveyance system, when the acceleration of movement of the OHT conveyance carriage 5 in the arrow direction A is gentle, the rotation moment caused by the inertial force acting on the FOUP 1 is sufficiently small, so that the rotation moment does not become a problem. However, in the present situation where improvement in the transport efficiency of the OHT transport cart 5 is strongly demanded, the OHT transport cart 5 needs a high-speed transport function. For this reason, the OHT transport carriage 5 is forced to accelerate rapidly. As a result, when the OHT transport cart 5 lifts the FOUP 1 and suddenly accelerates traveling in the traveling direction, or conversely, when the travel of the OHT transport cart 5 is suddenly decelerated from the top speed and stopped, the protrusion 12 of the FOUP 1 Is only supported uniformly on the entire contact surface of the finger portion 16, and the FOUP 1 is vibrated by the rotational moment.

  Further, the traveling rail 6 has a joint step and a step at the rail branching portion, and these steps are often enlarged due to deterioration of the traveling rail 6 itself or distortion and aging of the clean room building. A step such as a step existing on the traveling rail 6 or a groove existing in the rail branching portion generates a vertical vibration with respect to the FOUP 1. Further, the curved portion of the traveling rail 6 generates a left-right vibration with respect to the FOUP 1. Further, when the FOUP 1 is gripped and lifted, and when the FOUP 1 is placed on the load receiving table 8, a vertical vibration is generated with respect to the FOUP 1.

  These vibrations are gradually attenuated as vibration energy, but at the initial stage of the vibrations, the vibrations that cause problems are propagated to the silicon wafers that are stored in the FOUP 1 and are being manufactured. The vibration of the silicon wafer induces sliding friction at the contact surface between the silicon wafer and the cassette supporting the silicon wafer. Due to this sliding friction, particles are generated on the sliding surface, and the generated particles are scattered and adhere to the silicon wafer surface, inducing pattern defects and reducing the yield of the product.

  In Patent Document 1, an upper plate is provided via an air spring on an intermediate frame that is horizontally inserted into the outer frame and moves freely in four directions via an air spring, and a silicon wafer or the like is placed on the upper plate. In addition, an automatic guided vehicle running on the floor is disclosed in which the cassette is placed and transported so that the object to be placed has an anti-vibration property in the vertical and horizontal directions and in the front-rear direction.

JP 05-165524 A

  However, the configuration as in Patent Document 1 is a mounted object on which a seismic object is placed on a transport vehicle that runs on the floor and is not loaded with a rotational moment, and the seismic target is suspended on a suspended transport cart. The problem to be solved is different from this configuration, which is an object to be gripped with a rotating moment.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a suspended transport cart that can suppress vibrations caused by the rotational moment of the object to be gripped and vibrations in the vertical and horizontal directions. It is.

Means and effects for solving the problems

  A suspension type transport carriage according to the present invention includes a traveling unit that travels on a traveling rail, a gripping unit that is provided in the traveling unit and that can lift and lower in a suspended state by gripping a protrusion formed on the upper surface of the object to be gripped. A buffering means fixed to the gripping means so as to come into pressure contact with a predetermined position on the upper surface of the gripped object different from the formation position of the protrusion when the gripped object is raised by the gripping means; It is characterized by having.

  According to the present invention, the buffering means suppresses the vibration caused by the rotational moment loaded on the object to be gripped and the vibration in the vertical direction, so that the transfer efficiency of the suspension type transfer carriage can be improved.

  In the present invention, it is preferable that the predetermined position is symmetrically arranged with the protruding portion as a center. According to this, since the conveyed object is press-contacted at a position that is equidistant from both sides from the protruding portion, it is possible to suppress the inclination of the conveyed object when suspended.

  In the present invention, it is preferable that the predetermined positions are arranged at a plurality of locations on a straight line that coincides with the traveling direction. According to this, the object to be conveyed is pressed at a predetermined position existing at a plurality of locations on a straight line that coincides with the traveling direction, so that vibration in the traveling direction applied to the object to be grasped can be suppressed.

  In the present invention, it is preferable that the predetermined positions are arranged at a plurality of locations on a straight line orthogonal to the traveling direction. According to this, since the object to be transported is pressed at a plurality of predetermined positions on a straight line orthogonal to the traveling direction, the traveling object is loaded in the traveling direction loaded on the object to be gripped when traveling on the curved portion of the traveling rail. Vibration in the orthogonal direction can be suppressed.

  In this invention, it is preferable that the said buffer means is provided in the whole outer periphery of the lower surface of the said holding means. According to this, the vibration of all the directions loaded on a to-be-held object can be suppressed.

  In the present invention, it is preferable that the buffer means is composed of any one of a gel-like material, a sponge-like rubber, a spring, and a viscoelastic material, or a combination of two or more thereof. According to this, it can be set as the buffer means which gave desired hardness and damping.

  Hereinafter, an embodiment of a suspended transport cart according to the present invention will be described with reference to the drawings.

  The structure of the suspension type conveying cart of the present invention will be described with reference to FIGS. FIG. 1 is a side view showing the OHT transport cart 5 and its periphery, and only the traveling unit 3 is a cross-sectional view. FIG. 2 is a front view in which the gripping mechanism and the FOUP in FIG. 1 are enlarged from the front direction. FIG. 3A and FIG. 3B are bottom views of the gripping mechanism portion in FIG. FIG. 4 is a perspective view showing the configuration of an embodiment of the buffer means of the present invention.

  In FIG. 1, reference numeral 5 denotes an OHT transport cart that is a suspended transport cart, which is a gripping means that is suspended on a traveling rail 6 laid on the ceiling 9 and that can lift and lower in a suspended state by gripping the FOUP 1 that is the object to be gripped. A certain gripping mechanism 2 is provided. Reference numerals 18a, 18b, 18c, and 18d denote buffer members that are buffer means, and are fixed to the gripping mechanism unit 2 so as to be in pressure contact with predetermined positions on the upper surface of the FOUP 1.

  The suspension type transport cart 5 includes a gripping mechanism unit 2, a position adjustment unit 4, and a traveling unit 3.

  In FIG. 2, the gripping mechanism unit 2 includes a belt lifting mechanism 13, a belt 14, a gripping unit 15, finger units 16, a spacer 17, and the like.

  The belt elevating mechanism 13 lowers the gripping part 15 by rewinding the belt 14 and raises the gripping part 15 by winding up the belt 14. The finger portion 16 is attached to the tip of the gripping portion 15 and grips / releases a FOUP gripped portion 12 of the FOUP 1 described later. The spacer 17 is provided on the contact surface between the finger portion 16 and the FOUP gripped portion 12, and suppresses the sliding of the FOUP gripped portion 12 and the finger portion 16.

  In FIG. 1, the position adjusting unit 4 finely adjusts the position of the stopped OHT transport carriage 5 to accurately align the position of the OHT transport carriage 5 with respect to the load receiving base 8.

  The traveling unit 3 is a traveling means, and includes a primary side laminated core coil 23, a carriage suspension member 24, a secondary side core coil 25, a branch roller 29, and a traveling roller 30.

  The primary laminated core coil 23 forms a linear motor with the secondary permanent magnet 22 using the secondary permanent magnet 22 laid on the running rail 6 as a stator. The carriage suspension member 24 is coupled to the position adjustment unit 4 to suspend the gripping mechanism unit 2 and the position adjustment unit 4. The secondary side iron core coil 25 constitutes non-contact power feeding with the primary side power line 27 laid on the running rail 6, and the high frequency power applied to the primary side power line 27 receives the secondary side iron coil. By being guided to 25, electric power transmission is performed in a non-contact manner. All the electric power necessary for the OHT transport carriage 5 is covered by this non-contact power supply. The travel roller 30 travels on the travel rail 6, and the trajectory of the travel rail 6 is selected by the branch roller 29 selecting one of the branch guides 28 arranged on the left and right of the travel rail 6 at the branching portion.

  The FOUP 1 includes a FOUP storage portion 11 and a FOUP gripped portion 12. A silicon wafer (not shown) is stored in the FOUP storage unit 11. The FOUP gripped portion 12 is a protrusion formed on the upper surface of the FOUP 1 that is restrained by the finger portion 16 of the OHT transport carriage 5 and gripped. On the upper surface of the FOUP storage portion 11 different from the formation position of the FOUP gripped portion 12, there are predetermined positions where buffer members 18a, 18b, 18c, and 18d described later are pressed.

If the buffer members 18a, 18b, 18c, and 18d are rectangular parallel to the arrow direction A in which the lower surface of the belt elevating mechanism 13 is the traveling direction, as shown in FIG. The buffer member 18a and the buffer member 18d are arranged on a straight line that matches the traveling direction, and the buffer member 18b and the buffer member 18c are arranged on a straight line that also matches the running direction. Further, the buffer member 18a and the buffer member 18b are arranged on a straight line orthogonal to the traveling direction, and the buffer member 18c and the buffer member 18d are also arranged on a straight line orthogonal to the travel direction. The arrangement relationship is as described above, and is provided at the four corners of the lower surface of the belt lifting mechanism 13 here. In addition, the buffer members 18a, 18b, 18c, and 18d are arranged at positions opposite to predetermined positions provided on the upper surface of the FOUP storage unit 11 described above. Here, the number of buffer members 18a, 18b, 18c, and 18d is not limited to four, and may be provided on the entire outer periphery of the rectangle.
Further, the lower surface shape of the belt elevating mechanism 13 is not limited to a rectangular shape. For example, if the belt elevating mechanism 13 is circular as shown in FIG. 3B, the buffer members 18a, 18b, 18c, and 18d The four buffer members 18a, 18b, 18c, and 18d are arranged at positions that are opposed to four predetermined positions on the upper surface of the storage unit 11, and are the same as those in the case of the rectangle described above. Here, it is needless to say that the buffer members 18a, 18b, 18c, and 18d are not limited to four, and may be provided on the entire outer periphery of the circle.

  The buffer members 18a, 18b, 18c, and 18d are formed of gel material, sponge rubber, spring, viscoelastic material having a desired hardness and damping, durable, deformable, and dust-free structure. It is preferably composed of any one kind or a combination of two or more of these. Here, as shown in FIG. 4, a gel-like object 44 such as a theta gel is poured into a cylindrical rubber container 40, and after the gel-like object 44 is cured by heating, an attachment hole 42 for attaching to the belt lifting mechanism 13. It consists of the structure covered with the aluminum lid | cover 41 with which the air vent hole 43 was pierced. Here, it goes without saying that the air vent hole 43 is attached to the belt elevating mechanism 13 in a state of communicating with the outside air. Moreover, the shape of the buffer materials 18a, 18b, 18c, and 18d is not limited to a cylindrical shape.

  Next, the operation of the suspension type transport carriage of the present invention will be described with reference to FIG.

  The OHT transport cart 5 travels on a travel rail 6 attached to the ceiling 9 in a suspended state. Electric power is supplied to the OHT carriage 5 by a non-contact power feeding method including a primary side power line 27 laid on the running rail 6 and a secondary side core coil 25 of the running unit 3 of the OHT carriage 5. . The primary power supply line 27 is also used as a communication line between a transfer controller (to be described later) and the OHT transfer carriage 5.

  The OHT transport cart 5 is positioned on the load receiving platform 8 of the semiconductor manufacturing apparatus 7 and stops in an empty state without loading the FOUP 1. Next, the position adjustment unit 4 finely adjusts the position of the OHT transport carriage 5 and accurately aligns the position of the OHT transport carriage 5 with respect to the load receiving base 8 on which the FOUP 1 is placed.

  Next, the belt raising / lowering mechanism 13 is operated to rewind the belt 14 that has been wound up, so that a sensor (not shown) attached to the tip of the gripper 15 makes contact between the tip of the gripper 15 and the FOUP gripped part 12. The belt 14 is lowered until it is detected, and the rewinding of the belt 14 is stopped at the time of contact.

  Next, the finger portion 16 slides in the horizontal direction (left and right direction in FIG. 1), and the left and right ends of the FOUP gripped portion 12 are brought into contact with the spacer 17. As a result, the FOUP gripped portion 12 is gripped by the finger portion 16.

  Next, the belt lifting mechanism 13 switches the rotation of the belt winding motor in the belt winding direction, winds up the belt 14, and lifts the gripping part 15 to the top. As a result, the OHT transport carriage 5 holds the FOUP 1 in a suspended state. FIG. 1 illustrates this state.

  Next, the OHT transport cart 5 travels to the target point in response to a command from the system controller while holding the FOUP 1. At a part where there is a midway branch portion, one of the branch guide rails 28 laid on the traveling rail 6 is selected, and the branch roller 29 is pressed against the selected branch guide rail 28 to select a route.

  Next, after reaching the destination, the OHT transport cart 5 performs the transfer operation of the FOUP 1. The OHT transport carriage 5 arrives at the transfer position, stops, is accurately aligned by the position adjustment unit 4, and then unwinds the belt 14 that has been wound up to the top, so that the FOUP 1 is loaded on the semiconductor manufacturing apparatus 7. Lower to 8. When the bottom surface of the FOUP 1 comes into contact with the top surface of the load receiving table 8, a limit switch (not shown) attached to the load receiving table 8 operates to detect the landing of the FOUP 1, thereby stopping the belt 14 from being unwound. Thereafter, the gripping part 15 opens the finger part 16 and places the FOUP 1 on the load receiving table 8. After the FOUP 1 unloading operation is completed, the OHT transport carriage 5 winds up the belt 14 and, when the gripping part 15 reaches the uppermost part, proceeds to the next destination according to the next command.

  Next, the case where the OHT conveyance cart in the configuration of the prior art vibrates will be described with reference to FIG. FIG. 5 is an enlarged front view of the gripping mechanism unit 2 and the FOUP 1 in FIG.

  In FIG. 5, the gripping portion 15 is tightly wound up to the uppermost portion by the belt 14, so there is almost no slack in the belt 14, and the gripping portion 15 is integrated with the lower surface 19 of the belt lifting mechanism via a pulley that winds the belt 14. It has become. For this reason, even when the OHT transport carriage 5 accelerates traveling from the stationary state in the arrow direction A, the belt 14 does not vibrate. However, the restraining force P that restrains the FOUP 1 and is held by the finger portion 16 with the spacer 17 in contact is very weak and almost zero. Therefore, at the moment when the main body of the OHT transport carriage 5 moves in the arrow direction A, the force to move the FOUP 1 in the arrow direction A together with the OHT transport carriage 5 is the friction force on the contact surface between the FOUP 1 and the finger portion 16. Acts on the center of gravity P1. On the other hand, an inertial force acts on the FOUP 1, and this inertial force is larger than the frictional force, so that the contact surface between the finger portion 16 and the FOUP gripped portion 12 slips. The sliding of the FOUP gripped portion 12 is stopped by the spacer 17 at the right end of the finger portion 16, but the OHT transport carriage 5 body accelerates in the direction of arrow A, so the FOUP 1 has a rotational moment 33 around the center of gravity P 1 of the FOUP 1. Works.

In FIG. 5, it is assumed that the FOUP 1 is composed only of the gripped plate 10 of the FOUP gripped portion 12 and the gripped plate 10 has the total mass of the FOUP 1, and the rotation of the FOUP 1 by the rotational moment 33 occurs around the point P2. Is illustrated. The rotational moment 33 of the FOUP 1 around the point P2 can be expressed by [Formula 1] when the weight of the FOUP 1 is W.
[Formula 1] (Rotation moment) = W × L ²
Here, L is the distance from the point P2 to the point P3, that is, the length of the gripped plate 10.
When the rotational moment 33 around the point P2 is equal to or less than the value of [Expression 1], the finger part 16 and the FOUP gripped part 12 that are in contact with each other via the spacer 17 are not separated by rotation in the part P3. In the present situation where the OHT transport cart 5 moves at a high speed, the finger portion 16 and the FOUP gripped portion 12 that are in contact with each other via the spacer 17 are separated by rotation, and the FOUP 1 is vibrated due to the rotation.

  In addition, vertical vibration generated due to a step existing on the traveling rail 6 and a groove present on the track branching portion, horizontal vibration generated when traveling on a curved portion of the traveling rail 6, When the FOUP 1 is gripped and lifted, the vibration in the vertical direction when the FOUP 1 is placed on the load receiving platform 8 acts on the FOUP 1.

  Next, the operation and effect of the suspension type transport carriage in the configuration of the present invention will be described with reference to FIG. FIG. 2 is a front view in which the gripping mechanism 2 and the FOUP 1 in FIG. 1 are enlarged from the front direction.

  FIG. 2 shows a state in which the OHT conveyance carriage 5 holds the FOUP 1 in a suspended state by the belt lifting mechanism 13 hoisting the belt 14 and lifting the gripping part 15 to the uppermost part. At this time, the buffer members 18 a, 18 b, 18 c, and 18 d provided on the lower surface peripheral portion of the belt lifting mechanism 13 facing the FOUP 1 abut on a predetermined position of the FOUP storage portion 11. As a result, the FOUP gripped portion 12 is gripped and adhered to the finger portion 16 via the spacer 17 at two points P2 and P3, and is contacted and adhered to the two surfaces S1 and S2, so that the FOUP storage portion 11 is positioned at a predetermined position. Are in contact with and in close contact with the buffer members 18a, 18b, 18c and 18d at two points P4 and P5 and two predetermined positions (not shown).

  In particular, P4 and P5 and two points (not shown) are in a state of sandwiching the buffer materials 18a, 18b, 18c, and 18d, so that even if the OHT transport carriage 5 travels rapidly from a stopped state, the buffer member 18a, 18b, 18c and 18d absorb the rotational moment. Thereby, contact surface S1, S2 of the finger part 16 and the FOUP to-be-held part 12 is maintained, and FOUP1 is quake-proof.

  In addition, when traveling along the curve of the traveling rail 6, the vertical vibration caused by the step of the joint on the traveling rail 6, the step of the track branching section, the groove formed in the joint or the track branching section, or the curved section of the traveling rail 6 When the FOUP 1 is gripped and lifted, and when the FOUP 1 is placed on the load receiving table 8, the up-and-down vibration is also absorbed by the buffer members 18 a, 18 b, 18 c and 18 d. Thereby, FOUP1 is quake-proof.

  Moreover, although this invention was demonstrated based on suitable embodiment, this invention can be changed in the range which does not exceed the meaning. That is, the buffer members 18a, 18b, 18c, and 18d may be those in which the spring 45 is covered with the rubber tube 46 as shown in FIG. In this case, if it is attached to the belt lifting mechanism 13 using the same aluminum lid 41 as in FIG. Further, the shock absorbing members 18a, 18b, 18c and 18d may be shock absorbers having a structure in which the flow rate of the internal oil is adjusted by an orifice or the like.

  In the above-described embodiment, four buffer members are used. However, there may be four or more buffer members on a straight line that matches the traveling direction, for example, the same line connecting the buffer members 18a and 18d. One or more buffer members may be separately provided on the straight line. Similarly, there may be four or more buffer members present on a straight line orthogonal to the traveling direction. For example, one or more buffer members are separately provided on the same straight line connecting the buffer members 18a and 18b. May be. Needless to say, these buffer members abut on a predetermined position of the FOUP storage unit 11.

  In the above-described embodiment, a plurality of the same type of buffer members 18a, 18b, 18c, and 18d are used. However, different types of buffer means can be used at the same time as shown in FIG. Here, the other type of buffer means 20 is a silicon sponge provided in a horizontally long shape on a straight line that coincides with the traveling direction instead of the buffer members 18a and 18d.

It is the side view which showed the suspension type conveyance trolley | bogie which has the seismic-proof mechanism of this invention, and its periphery, and is a sectional view only of a running part. It is the front view which expanded the holding | grip mechanism part and FOUP in FIG. 1 from the front direction. It is the bottom view which looked at one form example of the grasping mechanism part in Drawing 1 from the lower surface direction. It is the bottom view which looked at another form example of the holding | grip mechanism part in FIG. 1 from the lower surface direction. It is a perspective view showing the structure of one Embodiment of the buffer means of this invention. It is the front view which expanded the holding | grip mechanism part and FOUP in FIG. It is the perspective view showing the structure of another embodiment of the buffer means of this invention. It is another bottom view which looked at the holding | grip mechanism part in FIG. 1 from the lower surface direction. It is the front view which showed the conventional suspension type conveyance trolley | bogie and its periphery.

Explanation of symbols

1 FOUP
DESCRIPTION OF SYMBOLS 2 Grip mechanism part 3 Traveling part 4 Position adjustment part 5 OHT conveyance trolley 6 Travel rail 7 Semiconductor manufacturing apparatus 8 Load receiving base 9 Ceiling 10 Grip board 11 FOUP accommodating part 12 FOUP grip part 13 Belt raising / lowering mechanism 14 Belt 15 Grip part 16 Finger part 17 Spacers 18a, 18b, 18c, 18d Buffer member 19 Lower surface of belt lifting mechanism 24 Bogie suspension member 25 Secondary iron core coil 26 Primary conductor 27 Primary power line 28 Branch guide rail 29 Branch roller 30 Traveling roller 33 Rotational moment

Claims (6)

Traveling means for traveling on the traveling rail;
A gripping means provided on the traveling means and capable of lifting and lowering in a suspended state by gripping a protrusion formed on the upper surface of the object to be gripped;
A buffering means fixed to the gripping means so as to come into pressure contact with a predetermined position on the upper surface of the gripped object different from the formation position of the protrusion when the gripped object is raised by the gripping means;
A suspension type transport cart characterized by comprising:   2. The suspended transport cart according to claim 1, wherein the predetermined positions are symmetrically arranged with the protruding portion as a center.   3. The suspended transport cart according to claim 1, wherein the predetermined position is arranged at a plurality of locations on a straight line that coincides with the traveling direction.   The suspended transport cart according to claim 3, wherein the predetermined position is arranged at a plurality of locations on a straight line orthogonal to the traveling direction.   The suspension type transport cart according to claim 1, wherein the buffer means is provided on the entire outer periphery of the lower surface of the grip means.   6. The buffering means according to claim 1, wherein the buffer means is composed of any one of a gel-like material, a sponge-like rubber, a spring, and a viscoelastic material, or a combination of two or more thereof. The hanging type transport cart according to Crab.

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