JP4308584B2 - Work transfer device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a work transfer device, and more particularly, to a work transfer device that sequentially feeds and moves a carriage placed on a rail laid along an assembly transfer path using a driving means for traveling.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a self-propelled cart system that can travel on a conveyance path has been widely used as a workpiece conveyance device in an automobile assembly line. This self-propelled cart system employs a system in which a drive motor is provided in the cart body, and the driving force of the drive motor is transmitted to the wheels so as to be self-propelled. A plurality of carriages are traveling on the conveyance path, and the running state of each carriage is kept stable by controlling the operation of the drive motor based on the detection result of the sensor or the like. The drive power supply method includes a current collection method, a battery method, and the like. The current collection method includes a current collecting unit that receives power from a feeder line laid along the conveyance path, and the battery method is a battery method. Equipped with each cart.
[0003]
In contrast to such a self-propelled carriage system, in recent years, the driving means for traveling is not provided in the carriage, but the driving means for traveling is provided on the transport path side, and the driving force obtained by the driving means for traveling is obtained. 2. Description of the Related Art Conveying devices that are sequentially fed and moved by applying to the side surface of the cart are known. (For example, refer to Patent Document 1).
[0004]
[Patent Document 1]
JP 2001-31378 A.
[0005]
According to the transport device disclosed in Patent Document 1, since it is not necessary to provide driving means for traveling such as a driving motor and a current collecting unit or a battery for each carriage, it is possible to improve a decrease in production efficiency due to a malfunction of the driving means. In addition, the manufacturing cost of the assembly line can be reduced. Specifically, a driving force is applied to the carriage by the driving means arranged and fixed at least on the starting end side in the assembling conveyance path to send it out to the end side of the conveyance path. Next, the following carriage is also sent to the terminal end side of the assembling conveyance path by the driving means for driving and comes into contact with the rear part of the adjacent carriage in front and boosts it. By sequentially repeating this, the cart given driving force by the driving means for traveling is traveling at a constant speed in a daisy chain toward the terminal end side of the assembling conveyance path. According to such a configuration, each carriage traveling on the transport path does not have the travel drive means, and travel travel force is applied by the travel drive means disposed and fixed in the transport path. Maintenance of the means is only required by periodically inspecting the drive motor constituting the driving means for driving and its peripheral parts, etc. Therefore, the maintenance efficiency is higher than that of the self-propelled cart system in which the driving means for driving is provided in each carriage. Can be greatly improved, and the equipment required for driving can be simplified, so the capital investment can be reduced.
[0006]
In an assembly line composed of such a transport device, an operator sequentially performs assembly operations assigned to the worker with respect to a workpiece placed on a carriage traveling at a constant speed. In general, an assembly line for automobiles has a production system that can increase the length of an assembly conveyance path in advance and respond to demands for increased production due to fluctuations in demand. At the time of production increase, the traveling speed of the carriage by the driving means for traveling can be set at a high speed, and many workers can perform many kinds of assembling work in parallel along the assembling conveyance path to increase the production amount. On the other hand, at the time of production reduction, a method is adopted in which the traveling speed of the carriage by the traveling drive means is set to a low speed and the total number of works passing through the assembly conveyance path per unit time is reduced. At this time, if the same number of workers as at the time of increased production are arranged, each worker will have an increased waiting time as the carriage travels at a low speed. Therefore, when the production is reduced, the number of workers is reduced, and one worker performs the work while holding it, so that the efficiency improvement in terms of human resource utilization is achieved.
[0007]
[Problems to be solved by the invention]
However, in the transport device disclosed in Patent Document 1, when the production is reduced, the number of workers engaged in the assembly work can be reduced by reducing the traveling speed of the carriage, and the efficiency improvement in human resource utilization can be achieved. Focusing on individual workpieces, the passing time for the workpiece to pass through the entire assembly conveyance path is prolonged, and the number of workpieces (in-process inventory) waiting for the next process on the assembly conveyance path increases. There was a problem of causing a drop in This will be described in more detail with a specific example. For example, consider a case where the production volume is reduced to 1/3 of the standard time. The traveling speed of the carriage is set to 1/3 of the standard time, but the work time required for the work assembly is almost unchanged, so the carriage is about a third of the assembly transport path from the start side. When reaching the above, the assembling work can be completed. At this time, the carriage continues to travel at a low speed over the remaining 2/3 of the entire assembly transport path, even though the workpiece can be transferred to the next process. That is, if the production volume is reduced to 1/3, the production time (the time required for the carriage to pass through the assembling conveyance path) is tripled, resulting in a delay in delivery of the product. In addition, a work waiting for the next process after completion of the work in the process stays in a range of 2/3 of the entire assembly transport path, and becomes an in-process inventory.
[0008]
The present invention has been conceived under such circumstances, and even when the production is reduced, the production efficiency is improved by reducing the number of workers and suppressing an increase in production time and an increase in inventory quantity. It is an object of the present invention to provide a work transfer device that can be used.
[0009]
[Means for Solving the Problems]
According to the present invention, a carriage that can be moved via wheels on a rail laid along an assembly conveyance path, and a drive for traveling that sequentially moves the carriage by applying a driving force to the side surface of the carriage. A driving device for traveling, the main driving means being disposed on the start end side of the assembling conveying path, and the end of the assembling conveying path with respect to the main driving means. and a fast-forward driving means disposed at two or more positions along the transport path for Oite the assembly to the side, the fast-forward drive means, the one-way clutch to the drive wheels, and the drive wheel in frictional contact with the carriage The fast-forwarding function and the receiving wheel function are combined, and the area where the fast-forward driving means is disposed along the assembly transport path serves as a fast-forwarding area and a work area. Is the characterized in that, the work conveying apparatus is provided.
[0010]
When the work transfer device having such a configuration is used, in the work area located on the start end side of the transfer path for assembly when the production is reduced, the traveling speed of the carriage by the main drive means is set to a low speed, and one worker is engaged. While it is possible to reduce the number of workers by holding and assembling work, in the fast feed area located on the terminal side of the assembly conveyance path from the main drive means, by setting the traveling speed of the carriage by the fast feed drive means at a high speed, The time for the carriage to pass through the fast-forward area where no assembly work is performed can be greatly reduced. As a result, it is possible to effectively suppress an increase in the transit time of the carriage that passes through the entire assembly transport path. Further, since the total number of workpieces existing in the entire assembly transport path can be reduced as compared with the case where the entire assembly transport path is traveled at a constant low speed, the in-process inventory quantity can be reduced. Furthermore, since the said workpiece conveyance apparatus is achieved by remodeling the existing conveyance apparatus and providing a fast-forward drive means, the amount of capital investment can be suppressed. In this way, when reducing production, it is possible to improve production efficiency and reduce capital investment while reducing the number of workers and suppressing an increase in production time and an increase in inventory quantity. Further, when there is a demand for increased production, the main drive means can be set at a high speed and all the above-mentioned fast-forwarding areas can be used as work areas. According to the above configuration, the structure of the fast-forward drive means can be simplified. Specifically, by providing driving wheels that are in frictional contact, it is possible to apply a driving force to the carriage only by rotating the driving wheels. Compared to driving methods that use a frictional contact body to apply driving force to the carriage while maintaining contact with the carriage, the structure can be simplified and the capital investment can be reduced. it can. Further, since the fast-forward drive means is provided with a one-way clutch for the drive wheels, the drive wheels can apply the traveling drive force to the carriage by operating the drive source of the fast-forward drive means at the time of production reduction. By stopping the drive source at the time of production increase, the drive wheel rotates while being in contact with the side surface of the carriage. That is, by adopting a one-way clutch, the operating state and the non-operating state of the fast-forward drive means are switched by simply performing an on / off operation of the drive source. Further, two or more fast-forward drive means are arranged along the assembly conveyance path. According to such a configuration, it is possible to fast-forward while maintaining a high speed without decelerating the traveling speed of the carriage. Specifically, when the fast-forwarding area extends over a long distance, it is possible to prevent a decrease in traveling speed of the carriage by providing fast-forwarding driving means at two or more appropriate locations.
[0013]
Preferably, the fast-forward drive means includes switching means for switching between a driving force transmission state and a driving force non-transmission state.
[0014]
According to such a configuration, when reducing production, the main drive means and the fast-forward drive means in the drive force transmission state are used in combination, thereby suppressing an increase in production time and an increase in inventory quantity, thereby improving production efficiency. On the other hand, when there is a demand for increased production, it is possible to easily shift to a production increase system with a large number of workers by switching the fast drive means to a non-driving state while increasing the speed of the main drive means. it can. Thus, in the case of a reduction in production, it is possible to improve the production efficiency while reducing the number of workers while suppressing an increase in production time and an increase in inventory quantity, and it is possible to quickly respond to a demand for an increase in production.
[0015]
Preferably, the switching means includes an advancing / retreating means for moving the fast-forward drive means forward / backward with respect to a side surface of the carriage.
[0016]
According to such a configuration, the switching operation by the switching unit can be reliably performed. Specifically, when the fast-forward driving means is in the driving force transmitting state, the advancing / retreating means is advanced to bring the fast-forward driving means and the side surface of the carriage into contact state, and when in the driving force non-transmitting state, the driving means is stopped. At the same time, the advancing / retreating means is retracted so that the fast-forward driving means and the side surface of the carriage are in a non-contact state. As a result, in the driving force non-transmitting state, not only the driving force can be surely stopped, but also contact resistance between the fast-forward driving means and the side surface of the carriage does not occur.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.
[0022]
FIG. 1 and FIG. 2 show the whole block diagram of the workpiece conveyance apparatus 1 concerning the 1st Embodiment of this invention. Reference numeral 10 denotes an assembly conveyance path, 11 denotes a return conveyance path, and 12 and 13 denote lifting conveyance paths. A main drive means 17 is disposed on the start end side of the assembly transport path 10, and a fast-forward drive means 18 is disposed at an appropriate position on the end side of the assembly transport path 10 with respect to the main drive means 17. The location of the fast-forward drive means 18 is determined according to the arbitrarily set reduction rate. In the present embodiment, three fast-forward drive means 18 are arranged at substantially equal intervals. A pair of rails 19 for running the carriage 2 on which the workpiece 4 is placed are laid on the assembly transport path 10 in substantially parallel, and work floors 14 are installed on both sides of the assembly transport path 10. Yes. The work floor 14 includes a work area 140 located on the start end side of the assembling conveyance path 10 (an area indicated by a left-downward broken hatching in FIG. 1) and a fast-forward area 141 located on the end side (lower right in FIG. 1). The area indicated by the broken line hatching in FIG. The fast-forward area 141 is used as a work area when the production is increased.
[0023]
The return transport path 11 is laid below the assembly transport path 10, and return drive means 110 is disposed at appropriate positions in the return transport path 11. In the present embodiment, three return drive means 110 are arranged at substantially equal intervals. A pair of rails 111 (only one appears in the side view of FIG. 2 but the plan view is the same as the rail 19 of the assembly conveyance path 10) for running the carriage 2 on the return conveyance path 11 are substantially parallel. Is laid.
[0024]
The lift transport paths 12 and 13 are provided at both ends of the assembly transport path 10 in the cart traveling direction, and the cart 2 can be transferred to the lift platforms 120 and 130, the assembly transport path 10, and the return transport path 11. And a pair of rails 121 and 131 laid in such a state, and elevating means 122 and 132 for reciprocating the elevating platforms 120 and 130 vertically and vertically via a chain or the like by a driving device such as a servo motor.
[0025]
Conveyance path transition driving means for smoothly transferring the carriage 2 that sequentially proceeds on each conveyance path to the next conveyance path at the end portions of the conveyance path 10 for assembly and the return conveyance path 11 and the lifts 120 and 130. 15 is disposed. In addition, guide wheels (not shown) that stabilize the traveling of the carriage are arranged in the assembly conveyance path 10 and the return conveyance path 11 as necessary.
[0026]
As shown in FIGS. 5 and 6, the carriage 2 includes a rectangular base plate 20 on which the workpiece 4 is placed, four wheels 21 a to 21 d that are pivotally supported in a rollable state on a pair of rails, Wheel frames 22a to 22d that are attached to positions corresponding to the pair of rails in the vicinity of the four corners of the lower part of the panel 20 and support the wheels.
[0027]
Similarly, as shown in FIGS. 5 and 6, the main drive means 17 rotates while contacting the drive motor 171 pivotally supported by the gantry 170 and one of the left and right side surfaces 23 a and 23 b of the carriage, thereby driving the drive motor 171. And a friction drive wheel 172 for applying the driving force to the carriage 2. A receiving wheel 173 that rotates in contact with the other of the left and right side surfaces 23a, 23b of the carriage is disposed at a position facing the friction drive wheel 172.
[0028]
As shown in FIGS. 7 and 8, the fast-forward drive unit 18 rotates in contact with the drive motor 181 that is pivotally supported by the gantry 180 and one of the left and right side surfaces 23 a and 23 b of the carriage 2, thereby driving the drive motor 181. And a friction drive wheel 182 for applying the driving force to the carriage 2. A receiving wheel 183 that rotates in contact with the other of the left and right side surfaces 23a and 23b of the carriage is disposed at a position facing the friction drive wheel 182. Further, the fast-forward drive means 18 includes advance / retreat means for advancing / retreating the gantry 180 with respect to one of the left and right side surfaces 23a, 23b of the carriage. The cylinder device 184 as the advance / retreat means includes a piston rod 185 that advances and retracts in a direction perpendicular to the side surface of the carriage by a driving force. The tip of the piston rod 185 is connected and fixed to the gantry 180.
[0029]
The use state of the workpiece transfer device 1 at the standard time (corresponding to the production increase after the production cut) will be described with reference to FIGS. The carriage 2 placed on the lifting platform 120 of the lifting transport path 12 located on the start end side of the assembly transport path 10 is raised to a height that can be transferred to the assembly transport path 10 by the lifting means 122. And the workpiece | work 4 (body of a motor vehicle in this embodiment) conveyed by another conveyor (not shown) from the upper direction of a raising / lowering conveyance path is mounted on the base plate 20 of the trolley | bogie 2. FIG. The carriage 2 on which the workpiece 4 is placed is sent to the assembling conveyance path 10 by obtaining a driving force by the conveyance path shift driving means 15 (same configuration as the main driving means 17). The carriage 2 that has entered from the start end side of the assembly conveyance path 10 is sent out toward the terminal end side of the assembly conveyance path 10 by friction drive wheels 172 that rotate while contacting the side surface 23a of the carriage. At this time, the drive motor 171 is driven so that the carriage 2 can travel at a high speed in the work area 140 (at the standard time, as shown in FIG. 3, almost the entire conveyance path for assembly is used as a work area and no fast-feed area is provided). The peripheral speed of the friction drive wheel 172 is set high by increasing the number of rotations. The rotation speed of the drive motor 171 can be changed by appropriate means such as an inverter. Subsequently, the carriage 2 that has entered the assembling conveyance path 10 is also sent out toward the end side of the assembling conveyance path 10 and comes into contact with the rear part of the adjacent adjacent carriage to boost it. By sequentially repeating this, the carriage 2 to which the driving force is given by the friction drive wheel 172 is traveling at high speed in a daisy chain toward the terminal end side of the assembly conveyance path 10 in the work area 140. The workers are arranged along the assembly conveyance path 10 and perform different operations. More specifically, each worker applies the work 4 placed on the carriage 2 from the work floor 14 to the worker's place (part of the work area 140 assigned to the worker). One kind of work such as assembly of parts is performed before passing through (region). At this time, the drive motor 181 of the fast-forward drive means 18 is stopped and the piston rod 185 of the cylinder device 184 is retracted (see FIG. 9). Then, the friction drive wheel 182 does not come into contact with the side surface 23a of the carriage, so that loss such as contact resistance does not occur, and the load on the drive motor 171 of the main drive means 17 is reduced.
[0030]
The carriage 2 that has reached the end side of the assembling conveyance path 10 is sent out to the up-and-down conveyance path 13 by the conveyance path shift driving means 15. The lifting platform 130 is waiting in advance in the lifting / lowering conveyance path 13 in advance, and the carriage 2 can be smoothly transferred from the assembly conveying path 10 to the lifting platform 130. After the carriage 2 moves on the lifting platform 130, the workpiece 4 is lifted by another conveyor (not shown) above the lifting conveyance path 13 and is sent to the next step as necessary.
[0031]
The elevator 130 on which the carriage 2 is placed is lowered by the elevator means 132. After the elevating table 130 reaches the lowered position, the carriage 2 obtains a driving force by the transfer path transfer driving means 15 and is sent out to the return transfer path 11. The carriage 2 that has entered the return conveyance path 11 moves to the end side of the return conveyance path 11 (the start end side of the assembly conveyance path 10) by the return drive means 110 (the same configuration as the main drive means 17). The carriage 2 that has reached the terminal end side of the return conveyance path 11 is sent out to the lift conveyance path 12 by the conveyance path shift driving means 15. The carriage 2 placed on the lifting platform 120 is raised to a height at which it can be transferred to the assembly conveyance path 10 by the lifting means 122.
[0032]
The use state of the work transfer device 1 at the standard time has been described along the movement of the carriage 2. Next, the use state of the work transfer device 1 at the time of production reduction when the production amount is reduced to ½ of the standard time is shown in FIG. This will be described with reference to FIG. The carriage 2 that has entered from the start end side of the assembly conveyance path 10 is sent out toward the terminal end side of the assembly conveyance path 10 by friction drive wheels 172 that rotate while contacting the side surface 23a of the carriage. At this time, the peripheral speed of the friction drive wheel 172 is set low by reducing the rotational speed of the drive motor 171 so that the carriage 2 can travel in the work area 140 at a speed lower than the standard time (1/2 speed of the standard time). is doing. Subsequently, the carriage 2 that has entered the assembling conveyance path 10 is also sent out toward the end side of the assembling conveyance path 10 and comes into contact with the rear part of the adjacent adjacent carriage to boost it. By repeating this sequentially, the carriage 2 to which the driving force is given by the friction drive wheel 172 is traveling in the work area 140 at a low speed in a daisy chain toward the terminal end side of the assembly conveyance path 10. At this time, the traveling speed of the carriage 2 is ½ of the standard time, and the time for the carriage 2 to pass through the operator's place is twice that of the standard time. Since the worker can carry out two types of work while passing through the worker's office, the number of workers can be reduced to ½.
[0033]
The carriage 2 that has passed through the work area 140 at low speed enters the fast-forward area 141. The carriage 2 that has entered the fast-forwarding area 141 is fed at high speed toward the terminal end side of the assembling conveyance path 10 by the friction drive wheel 182 that rotates while contacting the side surface 23a of the carriage. At this time, the piston rod 185 of the cylinder device 184 is in the advanced position, and the friction drive wheel 182 is in a state where it can apply a travel driving force while contacting the side surface 23a of the carriage (see FIG. 8). The peripheral speed of the friction drive wheel 182 is set high. When the cart 2 sent out at a high speed stalls a little due to the frictional resistance of the wheels, the cart 2 reaches the second fast-forward drive means 18. Also here, as in the previous case, the friction drive wheel 182 feeds out at a high speed. This is sequentially repeated, and the carriage 2 travels at a high speed in the fast-forwarding area by the fast-forward driving means 18 provided at three locations, so that the passing time of the carriage 2 in the fast-forwarding area 141 is greatly shortened. Conventionally, although the assembly operation of the workpiece 4 can be completed when the point reaches about a half of the starting end side of the assembling conveyance path 10, the end of the assembling conveyance path 10 is approximately 1/2. The trolley 2 continued to run at a speed of 1/2 of the standard time over a distance of 2. As a result, the production time (the time required for the carriage 2 to pass through the assembly conveyance path 10) is doubled, resulting in a delay in delivery of the product and a gap in the range of about ½ of the end side of the assembly conveyance path 10. The workpieces 4 placed on the carts 2 that were lined up were not yet in stock. In the present embodiment, since the carriage 2 is fast-forwarded when the assembly work is completed, it is possible to suppress the lengthening of the production time when the production is reduced and to reduce the in-process inventory.
[0034]
Although the case where the production is reduced to 1/2 of the standard time has been described above, when the degree of production reduction is small (for example, 2/3 of the standard time), the rotation speed of the drive motor 171 can be changed in accordance with the degree of production reduction. At this time, it is not always necessary to operate the fast-forward drive means 18 at three locations at the same time. Either one location on the start end side of the assembling transport path 10 is deactivated and two locations on the end side are operated, or two locations on the start end side are operated. One place on the terminal side may be operated as non-operating. In addition, the total number of carriages 2 that travel on each conveyance path of the workpiece conveyance device 1 during production reduction is set to be smaller than that in the standard time. Since other use states are the same as in the standard time, the description thereof is omitted.
[0035]
FIG. 10 shows the fast-forward drive means 18 of the workpiece transfer apparatus according to the second embodiment of the present invention. This embodiment does not include advancing / retreating means, and the friction drive wheel 182 is always fixed at a position in contact with the side surface 23a of the carriage. A one-way clutch is built in between the drive motor 181 and the friction drive wheel 182. At the time of production reduction, the drive motor 181 of the fast-forward drive means 18 is operated to apply traveling driving force to the carriage. When the drive motor 181 is stopped at the standard time, the friction drive wheel 182 contacts the side surface of the carriage and rotates in a driven manner, and functions as a receiving wheel, so that loss such as rotational resistance of the drive motor 181 does not occur. As described above, the operating state and the non-operating state of the fast-forward drive unit 18 are switched only by performing an on / off operation of the drive motor 181, so that the structure of the fast-forward drive unit 18 can be simplified. Since other configurations are the same as those of the first embodiment, the same members are denoted by the same reference numerals, and the description thereof is omitted.
[0036]
While specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention. For example, the work that is the work target may be of any type, and depending on the type of work, a work table provided with lifting means may be provided on the platform.
[0037]
【The invention's effect】
According to the present invention, in the work transfer device that sequentially moves the carriages placed on the rails laid along the assembly transfer path by the driving means for traveling, the number of workers is reduced even when the production is reduced due to fluctuations in demand. However, it is possible to improve production efficiency by restraining prolonged production time and increase in inventory quantity. Furthermore, the present invention can be modified by simply adding a fast-forward drive means to an existing workpiece transfer device, so that it is advantageous in terms of cost and can flexibly respond to a demand for increased production due to fluctuations in demand.
[Brief description of the drawings]
FIG. 1 is a plan view showing an overall configuration of a workpiece transfer apparatus according to the present invention during production reduction.
FIG. 2 is an AA view of FIG.
FIG. 3 is a plan view showing the overall configuration of the workpiece transfer apparatus according to the present invention at the standard time.
4 is a BB view of FIG. 3;
FIG. 5 is a plan view showing main driving means and a cart according to the present invention.
6 is a CC view of FIG. 5;
FIG. 7 is a plan view showing fast-forward drive means and a cart according to the first embodiment of the present invention.
FIG. 8 is a DD view of FIG. 7;
FIG. 9 is a view similar to FIG. 8 showing the non-transmission state of the fast-forward drive means and the carriage according to the first embodiment of the present invention.
FIG. 10 is a view similar to FIG. 8 showing fast-forward drive means and a cart according to the second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Work conveyance apparatus 2 Cargo 4 Work 10 Assembly conveyance path 17 Main drive means 18 Rapid feed drive means 23a Side surface 23b Side surface

Claims (1)

A carriage capable of moving via wheels on a rail laid along the assembly conveyance path, and a traveling drive means for sequentially feeding and moving the carriage by applying a driving force to the side surface of the carriage. A workpiece transfer device,
The traveling drive unit includes a main driving means disposed at the starting end side of the conveying path for the assembly, along the transport path for Oite the assembly at the end side of the conveying path for the assembly than the main driving means Two or more fast-forward drive means ,
The fast-forward drive means is configured to have both a fast-forward function and a receiving wheel function by including a drive wheel that frictionally contacts the carriage, and a one-way clutch for the drive wheel.
An area along the assembling conveyance path where the fast-forward driving means is disposed is used as a fast-forwarding area and a work area .

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