JPH04293662A - Work conveying method and work conveying device - Google Patents

Abstract

PURPOSE:To provide the work conveying method and work conveying device capable of rotatively driving a work in the preset rotation direction with small rotation driving force, miniaturizing a rotation driving means, and improving the durability of the work conveying device. CONSTITUTION:Rotation support sections 20, 20A supporting a vehicle body B rotatably around the nearly horizontal rotation center Cr are provided on a bogie 10, the rotation support sections 20, 20A are constituted so that the center of gravity Cw of the vehicle body B and the rotation support sections 20, 20A is off-centered downward in the vertical direction against the rotation center Cr when they are positioned at the erect position, a guide member 64 for rotating the vehicle body B by the preset angle in the direction opposite to the preset rotation direction is provided near the upstream of a drying station ST4 where the rotation of the vehicle body B is started, and the vehicle body B is rotatively driven in the preset rotation direction when it is rotated to the preset rotation direction from the opposite direction by its tare weight.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a workpiece conveyance method and a workpiece conveyance apparatus, and more particularly to a workpiece conveyance method and a workpiece conveyance apparatus that use a cart to convey a workpiece while rotating it in a predetermined rotational direction around a substantially horizontal center of rotation. Regarding.

0002

[Prior Art] Generally, in the painting process of an automobile manufacturing factory, a plurality of carts that support the car body and a traveling drive that drives the carts are used as a transportation method to transport the car body between work stations such as a painting station and a drying station. A method of transporting using a vehicle body transporting device equipped with means is widely adopted. Incidentally, in recent years, in car body painting, especially in top coat painting, progress has been made to improve the quality of car body painting by applying the paint to a thickness greater than the sag limit. In this case, in order to control the sagging of the paint after painting, in the vehicle body conveying device, for example, Utility Model Application Publication No. 1983-126064 or Utility Model Application No. 1-341 filed by the applicant of the present application.
As described in No. 00, a rotation support part that supports a vehicle body rotatably around a substantially horizontal rotation center, the rotation support part configured such that the center of gravity of the vehicle body and the rotation support part substantially coincides with the rotation center. A support part is provided on the trolley, and a rotary drive means is provided to rotate the rotary support part in a predetermined rotational direction, and after painting the car body in an upright position at the painting station, A transportation method is used in which a cart is run while rotating the vehicle body.

0003

[Problems to be Solved by the Invention] In the transportation method using the vehicle body transportation device described in the above-mentioned publication, a large rotational starting force is required when starting the vehicle body from an upright position.
Therefore, there is a problem in that the drive source such as an electric motor and the component parts of the rotational drive means are increased in size. In addition, when the rotation is started, a large impact load is applied to the components of the rotation drive means and the components of the rotation support, which reduces the durability of these components and reduces the durability of the vehicle body transfer device. There's a problem. Furthermore, since the center of gravity of the vehicle body and the rotational support section is configured to approximately coincide with the center of rotation, the vehicle body does not always stop in an upright position when the rotational drive is stopped, and the vehicle body may be moved to the next position. In order to transport the car body in an upright position for the process described above, the car body transport device must be equipped with a rotation drive means to return the car body to the upright position, a detection means to detect the upright position while the car body is rotating, etc. However, there are problems in that the manufacturing cost of the vehicle body transfer device increases and the work efficiency decreases.

An object of the present invention is to provide a workpiece that can smoothly rotate a workpiece in a predetermined rotational direction with a small rotational starting force, downsize the rotational drive means, and improve the durability of the workpiece conveyance device. An object of the present invention is to provide a transportation method and a workpiece transportation device.

[0005]

[Means for Solving the Problems] A workpiece conveying method according to claim 1 includes rotatably supporting a workpiece on a cart via its rotation support portion, and rotating the workpiece in a predetermined rotational direction around a substantially horizontal rotation center. In a workpiece transfer method in which a trolley is run while the workpiece is in an upright position, the workpiece is supported on the rotational support section so that the center of gravity of the workpiece and the rotational support section is eccentrically downward in the vertical direction with respect to the center of rotation. Rotation drive means rotates the work by a predetermined angle in a direction opposite to the predetermined rotation direction when starting the rotation of the workpiece, and then rotates the rotation support part while the work is inertially rotating in the predetermined rotation direction due to its own weight. This is what activates it.

[0006] In the workpiece conveyance device according to the second aspect, a rotational support portion for rotatably supporting the workpiece around a substantially horizontal rotation center is provided on the cart, and a rotational drive means for rotationally driving the rotational support portion in a predetermined rotational direction. and a workpiece transporting device configured to include a travel drive means for driving the trolley so that the trolley travels while rotating the workpiece in a predetermined rotational direction via the rotational support section, the rotational support section is configured to rotate the workpiece in a predetermined rotational direction. When the rotating support is in an upright position, the center of gravity of the rotating support is eccentric downward in the vertical direction with respect to the center of rotation, and the work is placed in a predetermined rotation direction near the position where the rotation of the work is started. A rotating means for rotating a predetermined angle in the opposite direction is provided, and a starting means is provided for starting the rotation drive means while the workpiece rotated by the rotating means is rotated in the predetermined rotational direction due to its own weight. .

[0007]

[Operation] In the method for transporting a workpiece according to claim 1, when transporting the workpiece, the workpiece and the rotating support part of the cart are placed in an upright position, and the center of gravity of the workpiece and the rotating support part is the center of rotation. It is supported by a rotation support part so as to be eccentric downward in the vertical direction. Next, when starting the rotation of the workpiece, the workpiece is rotated by a predetermined angle in the opposite direction to the predetermined rotational direction, and then, while the workpiece is inertially rotating in the predetermined rotational direction due to its own weight, the rotation drive means is activated to rotate the workpiece. By rotationally driving the support part, the workpiece is continuously rotated in a predetermined rotation direction. In this way, while the workpiece is inertially rotating in a predetermined rotational direction due to its own weight, the rotational driving means is activated to rotationally drive the rotational support portion, so that the workpiece can be smoothly rotated in the predetermined rotational direction with an extremely small starting force. The drive source and components of the rotational drive means can be miniaturized. In addition, when the rotation is started, a large impact load is not applied to the components of the rotation drive means and the components of the rotation support part, so the durability of these components can be increased, increasing the durability of the workpiece conveyance device. I can do it. Furthermore, when the workpiece is in the upright position, the center of gravity of the workpiece and the rotating support section is eccentrically downward in the vertical direction with respect to the center of rotation, and when the rotational drive of the workpiece is stopped, the workpiece is always in the approximately upright position. Since the workpiece is stopped, the workpiece can be easily positioned in the upright position, and a means for returning the workpiece to the upright position and a detection means for detecting the upright position of the workpiece can be omitted. It is possible to reduce the manufacturing cost of the device and improve work efficiency.

In the work conveyance device according to the second aspect of the present invention, when conveying the work, the work and the rotating support portion of the cart are placed in an upright position, and the work is supported by the rotating support portion in this state. At this time, the centers of gravity of the workpiece and the rotational support section are offset downward in the vertical direction with respect to the center of rotation. Next, when the workpiece is transported by the trolley to an upstream vicinity of the position where rotation starts, the workpiece is rotated by a predetermined angle in a direction opposite to the predetermined rotation direction by the rotating means. Next, while the workpiece is rotating in a predetermined rotational direction due to its own weight, the rotation drive means is activated by the starting means, and the workpiece is continuously rotated in the predetermined rotational direction. In this way, while the workpiece is inertially rotating in a predetermined rotational direction due to its own weight, the rotational driving means is activated to rotationally drive the rotational support portion, so that the workpiece can be smoothly rotated in the predetermined rotational direction with an extremely small starting force. Therefore, the rotational drive means and the starting means can be miniaturized. In addition, when the rotation is started, a large impact load is not applied to the rotational drive means, the starting means, and the components of the rotation support part, so the durability of these parts can be increased, and the durability of the workpiece conveyance device is increased. I can do it. Furthermore, when the workpiece is in the upright position, the center of gravity of the workpiece and the rotating support section is eccentric downward in the vertical direction with respect to the center of rotation, and when the rotational drive of the workpiece is stopped, the workpiece always stops in the approximately upright position. Therefore, the workpiece can be easily positioned in an upright position, and the rotational drive means and detection means for returning the workpiece to the upright position can be omitted, reducing the manufacturing cost of the workpiece conveyance device and improving work efficiency. It is possible to improve the

[0009]

According to the method for transporting a workpiece according to claim 1, as explained in the section of the operation, the rotational driving means is activated while the workpiece is inertially rotating in a predetermined rotational direction due to its own weight to move the rotational support part. Since it is rotationally driven, the workpiece can be smoothly rotated in a predetermined rotational direction with an extremely small starting force, and the rotational drive means can be downsized. Since no large impact load is applied to these parts, the durability of those parts can be increased, and the durability of the workpiece conveyance device can be increased. Since it stops in the upright position, the workpiece can be easily positioned in the upright position, and means for returning the workpiece to the upright position and detection means for detecting the upright position of the workpiece can be omitted. , the production cost of the workpiece conveyance device can be reduced, the work efficiency can be improved, and other effects can be obtained.

According to the workpiece conveyance device according to claim 2,
As explained in the section above, the rotary support section is configured so that when the workpiece and the rotary support section are in the upright position, their centers of gravity are eccentric downward in the vertical direction with respect to the center of rotation, and the workpiece is It has a simple configuration that includes rotation for rotating a predetermined angle in the opposite direction to the predetermined rotation direction, and a starting means for starting the rotation means while the workpiece is rotating in the predetermined rotation direction due to its own weight.
The workpiece can be started to rotate smoothly with an extremely small rotational starting force, the rotational driving means and the starting means can be downsized, and when starting the rotational work, a large impact load can be applied to the rotating driving means, the starting means and the rotational support part. Since they do not work, their durability can be increased, and the durability of the workpiece conveyance device can be increased, and when the rotational drive of the workpiece is stopped, the workpiece can be easily positioned in an upright position. Since it is possible to omit the means for returning the workpiece to the upright position and the detection means for detecting the upright position of the workpiece, the production cost of the workpiece conveyance device can be reduced and work efficiency can be improved. can get. .

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment is used in the top coating process of a car body painting line in an automobile manufacturing factory.This example describes a car body transport system in which a car body supported by a cart is rotated in a predetermined rotation direction around a substantially horizontal rotation center in the longitudinal direction of the car body while the cart runs. The present invention is applied to a method and a vehicle body transport device. Note that the front, rear, left, and right will be defined and explained based on the front, rear, left, and right of the vehicle body.

First, the top coating step UP will be briefly explained. As shown in FIG. 1, the top coating process UP is provided with a carry-in station ST1, a top coat station ST2, an unlocking station ST3, a drying station ST4, and a carry-out station ST5 from the upstream side. A vehicle body transport device HS is provided which includes a plurality of trolleys 10 (see FIG. 2) for transporting the vehicle body between stations ST1 to ST5. Note that each truck 10 is circulated through each station ST1 to ST5. Loading station ST1 is equipped with four sets of vehicle body fixing devices.
The vehicle body B, which has been coated with an intermediate coating in an intermediate coating step (not shown), is transported to a carry-in station ST1 by a hanger, and is fixed to a bogie 10 in an upright position (see FIG. 2) by a vehicle body fixing device. Next, the car body B is conveyed to the topcoating station ST2, and the car body B is conveyed to the downstream side, for example, by about 60 μm.
is coated with a top coat to a thickness of , and then transported to the unlocking station ST3. Unlock station ST
3 is provided with a lock release device, and the vehicle body B is released from a state fixed in an upright position by the lock release device to a state in which it can rotate around a rotation center Cr (see Fig. 2) in the longitudinal direction of the vehicle body. It is transported to the drying station ST4 in this state. A guide member 64 constituting a rotation mechanism 60 is provided near the upstream side of the drying station ST4, and an endless chain 58 constituting the rotation drive mechanism 50 is provided downstream of the drying station ST4.
Then, the vehicle body B is rotated by a rotation mechanism 60 around the rotation center Cr clockwise by a predetermined angle when viewed from the rear side, and then continuously rotated clockwise around the rotation center Cr by the rotation drive mechanism 50. During this time, the coating film is dried and baked. Next, the vehicle body B is switched to free rotation and transported to the unloading station ST5. The unloading station ST5 is equipped with four sets of vehicle body fixing release devices.
The vehicle body B is positioned in an upright position by the vehicle body fixing release device, and is released from being fixed to the truck 10. Thereafter, the vehicle body B is carried out to the next process by a hanger, and the truck 10 is transferred to the carry-in station ST1 side. It has become. In addition, in the following explanation, among the vehicle body transport devices HS,
The trolley 10, the rotation drive mechanism 50, and the rotation mechanism 60 will be described, and the description of the vehicle body fixing device, lock release device, and vehicle body fixation release device will be omitted.

Next, the trolley 10 will be explained. Figure 2~
As shown in Figure 4, each station ST in the painting process UP
Carts 10 are provided in the following manner on the transfer line L provided in the front-rear direction on the floor F from ST1 to ST5. The trolley 10 includes a base portion 11 extending in the front-rear direction,
Column parts 1 erected at the rear end and front end of the base part 11, respectively
2 and 13, and the column parts 12 and 13, respectively, are installed on the vehicle body B.
Rotating support part 2 that supports rotatably around the rotation center Cr.
0.0.20A, etc., and the trolley 10 is movably disposed along the rail 1 laid in the forward and backward direction on the transfer line L via support wheels 14 and 15 attached to the base part 11, and is It is adapted to be moved and driven by a chain type drive mechanism (not shown) provided on the line L. Note that reference numeral 16 is an auxiliary rolling wheel provided on the base portion 11, and reference numeral 17 is a support wheel that rolls on a rail when the trolley 10 is returned from the carry-out station ST5 to the carry-in station ST1.

Next, the rotation support part 20 provided on the column part 12 on the rear side of the truck 10 and the rotation support part 20A provided on the column part 13 on the front side will be explained. Since the front and rear rotation support parts 20 and 20A have substantially the same configuration, the rear rotation support part 20 will be explained first, and the front rotation support part 20 will be explained first.
Regarding A, the same reference numerals are given to the same members as those of the rotation support part 20, detailed explanation is omitted, and different points will be explained. As shown in FIGS. 2 to 4, a gearbox 21 provided at the upper part of the column part 12 has a shaft member 23 that is freely rotatable in the front-rear direction and aligned with the rotation center Cr via front and rear bearings 22. A pivot member 24 is provided at a front end portion of the shaft member 23 protruding from the gear box 21, and has an arm portion 24a projecting forward below the rotation center Cr and an extension portion 24b extending downward. A support member 25 extending a predetermined length from side to side is fixed to the front end of the arm portion 24a. At the left and right ends of the upper end of the support member 25, engagement holes 25a that are circular in plan view are respectively provided, and toggle type clamps 30 are provided at the left and right ends of the front end of the support member 25, respectively, oriented in the left-right direction. It is being

As shown in FIGS. 2 and 5, an engagement hole 24c is formed in the lower end of the extension part 24b of the pivot member 24 in the front-rear direction, and the rotation support part 20 is in the upright position (the pivot member 24 When the extension part 24b is in the vertically downward position), the part of the column part 12 facing the engagement hole 24c is provided with a toggle type for restraining the rotation of the rotation support part 20 about the rotation center Cr. A clamp tool 30 is provided in the front-rear direction. On the other hand, the pivot member 24A of the front rotation support part 20A is formed with an arm part 24a projecting rearward below the rotation center Cr, but an extension part 24b is not formed. A support member 25A extending a predetermined length from side to side is fixed to the rear end of the arm portion 24a of the pivot member 24A.
Engagement holes 25b that are long in the front-rear direction are formed at the left and right ends of the upper end of the support member 25A, respectively, and clamp tools 30 are provided in the left and right ends of the front end of the support member 25A, respectively. Note that the shaft member 23A is provided to coincide with the rotation center Cr. In this way, the rotation support part 20
20A, as shown in FIG. 2, when the vehicle body B is supported in the upright position by the rotational supports 20 and 20A in the upright position, the center of gravity Cw of the vehicle body B and the rotational supports 20 and 20A is is eccentric downward in the vertical direction with respect to the rotation center Cr.

The holding frame 40 attached to the front end and rear end of the vehicle body B will now be described. However, since the front and rear holding frames 40 have the same configuration, the holding frame 40 attached to the rear end will be described. As shown in FIGS. 2 and 4, the holding frame 40 includes a pair of left and right fixing members 41 fixed downward to the rear end of the vehicle body B, and left and right fixing members having approximately the same length as the support member 25. A connecting member 42 is fixedly attached to the connecting member 41 and provided in the left-right direction, an engaging pin 43 is fixedly attached to the lower end of each fixing member 41, and a connecting member 43 is fixedly fixed downwardly to the left end and the right end of the rear end of the connecting member 42, respectively. The engagement member 44 has an engagement hole 44a formed at its lower end, and the distance between the left and right engagement pins 43 is equal to the distance between the left and right engagement holes 25a of the support member 25.

Next, the rotational drive mechanism 50 will be explained. As shown in FIGS. 2 and 4, a shaft member 51 is provided at the rear end of the base portion 11 of the truck 10 so as to be rotatable in the left-right direction, and a sprocket 52 is attached to the right end of the shaft member 51. There is. A shaft member 53 is provided on the column portion 12 of the truck 10 so as to be freely rotatable in the vertical direction, a bevel gear 54 is attached to the lower end of the shaft member 53, and a bevel gear 55 attached to the shaft member 51 is attached to the bevel gear 54. A bevel gear 56 is mounted on the upper end of the shaft member 53, and the bevel gear 56 meshes with a bevel gear 57 mounted on the shaft member 23. On the other hand, on the right side of the transfer line L corresponding to the drying station ST4, excluding the vicinity upstream of the drying station ST4, an endless chain 58 is provided in the front-rear direction.
8 is rotationally driven in a direction opposite to the transport direction of the vehicle body B by a drive device (not shown). Incidentally, reference numeral 59 is a guide ring provided on the endless chain 58.

The vehicle body B, which has been carried in an upright position to a predetermined position of the carry-in station ST1 by the hanger, is transferred to the trolley 10 that is stopped at the carry-in station ST1. At this time, the front and rear rotational supports 20 and 20A are in the upright position, and the vehicle body B connects the engagement pins 43 of the front and rear holding frames 40 to the corresponding engagement holes of the front and rear rotational supports 20 and 20A, respectively.
5a and 25b, it is positioned on the trolley 10. After that, the column part 1 is fixed by the vehicle body fixing device.
2 clamp tool 30 and front and rear rotation support parts 20 and 20A
The operating lever 31 of the clamping tool 30 is rotated, and as shown in FIG. The lock position protruding from the sleeve 33 from
(solid line shown), and the engagement hole 24c of the extension portion 24b
By engaging the engagement pin 32 with the rotation support part 20
is locked in the upright position, and similarly the front and rear rotational supports 20
- The engagement pins 32 of the 20A clamp tool 30 are switched from the non-locking position to the locking position, and each engagement pin 32 engages with the engagement hole 44a of the corresponding connecting member 44, so that the rotation support part 20- Even when 20A is rotated,
The vehicle body B is fixed to the truck 10 so as not to fall off. After the vehicle body B is fixed to the bogie 10 in this way, the bogie 10
is moved downstream and a top coat is applied to the vehicle body B in the upright position at the top coat station ST2.Next, at the lock release station ST3, the engagement pin 32 of the clamp tool 30 of the column part 12 is unlocked by the lock release device. It is switched to the lock position, and the vehicle body becomes rotatable around the rotation center Cr.

Next, the rotation mechanism 60 will be explained. As shown in FIGS. 2 and 4, the rotation mechanism 60 includes a base portion 11
A lever member 61 attached to the left end of the shaft member 51 protruding from the rear end, and front and rear support members 62 and 63 fixed vertically to the left end of the transfer line L near the upstream of the drying station ST4. , a guide member 64 having an L-shaped cross section and a predetermined length, and the guide member 64 is comprised of a support member 6
The upper wall portion 64a of the upper wall portion 64a is fixed to the inner surface of the upper portion of the rotary support portion 2.63 so as to be inclined forwardly downward so as to be able to come into contact with the lever member 61. It is attached to the shaft member 51 so that still,
The distance between the rear end of the endless chain 58 and the front end of the guide member 64 is set to a predetermined distance.

Next, a method of transporting a vehicle body using the vehicle body transporting device HS will be explained. As described above, at the lock release station ST3, when the vehicle body B becomes rotatable around the rotation center Cr by the lock release device and is transported to the upstream vicinity of the drying station ST4, the lever member 61 is moved from the guide member 64. During this time, the lever member 61 is rotated clockwise to rotate the shaft member 51, and this rotational force is transmitted through the bevel gears 54 and 55, the shaft member 53, and the bevel gears 56 and 57. The transmission is transmitted to the shaft member 23, and the shaft member 23 is rotationally driven, so that the vehicle body B rotates clockwise at a predetermined angle (for example, approximately 4
5°) rotate. After that, when the lever member 61 passes the guide member 64, as shown by the arrow in FIG.
is conveyed to the downstream side while rotating inertia in the counterclockwise direction due to its own weight, and as shown in FIG.
This corresponds to the starting means. ), the sprocket 71 is rotationally driven and the shaft member 51 is rotated, and this rotational force is transmitted to the shaft member 23 in the same manner as described above, the shaft member 23 is rotationally driven, and the rotation support portions 20 and 20A rotate the vehicle body B. rotates continuously in a clockwise direction. Thereafter, when the truck 10 moves to the downstream end of the drying station ST4, the engagement between the sprocket 52 and the endless chain 58 is released, the rotational drive of the vehicle body B is stopped, and the vehicle body B is switched to free rotation. Next, at the unloading station ST5, the vehicle body B is positioned in an upright position by the vehicle body fixing release device and is released from being fixed to the trolley 10.

In this way, since the rotation drive mechanism 50 is activated to rotationally drive the rotation support parts 20 and 20A while the vehicle body B is inertially rotating clockwise due to its own weight, the rotation of the vehicle body B in the clockwise direction is extremely small. The rotation can be started smoothly by force, and the rotation drive mechanism 50 can be downsized. In addition, when the rotation is started, a large impact load is not applied to the components of the rotation drive mechanism 50 and the rotation support parts 20 and 20A, so the durability of these components can be increased, and the durability of the vehicle body transfer device HS can be improved. can be increased. Furthermore, the vehicle body B and the rotation support parts 20, 20 in the upright position
Since the center of gravity Cw with respect to A is eccentric downward in the vertical direction with respect to the rotation center Cr, and when the rotational drive of the vehicle body B is stopped, the vehicle body B always stops in a substantially upright position, so at the unloading station ST5, The vehicle body B can be easily positioned in the upright position, and a rotational drive mechanism and detection mechanism for returning the vehicle body B to the upright position can be omitted.
It is possible to reduce manufacturing costs and improve work efficiency. Note that it is also possible to configure the trolley 10 to be self-propelled. Further, an extension portion 2 is attached to the pivot member 24A of the rotation support portion 20A.
4b, and an extension member 24 on the column part 13.
Clamping tools 30 may be provided in correspondence with b, and the rotational supports 20 and 20A may be locked unrotatably by these clamping tools 30 when the vehicle body B is transferred to the trolley 10 at the loading station ST1.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the top coating process.

FIG. 2 is a partially cutaway side view of the truck.

FIG. 3 is a plan view of the truck.

[Figure 4] Cross-sectional view taken along line 4-4 in Figure 2

FIG. 5 is a side view of the clamp tool.

FIG. 6 is an explanatory diagram showing the rotation of the vehicle body by the rotation mechanism.

FIG. 7 is an explanatory diagram showing inertial rotation of the vehicle body in a predetermined direction.

FIG. 8 is an explanatory diagram showing starting rotation of the vehicle body in a predetermined direction.

[Explanation of symbols]

B Vehicle body Cr Center of rotation Cw Center of gravity HS Vehicle body transfer device 10 Trolley 20/20A Rotating support part 50 Rotation drive mechanism 60 Rotating mechanism

Claims (2)

[Claims] Claims: 1. A workpiece transport method in which a workpiece is rotatably supported by a dolly via its rotation support part, and the dolly travels while rotating the workpiece in a predetermined rotational direction around a substantially horizontal rotation center. The work is supported by the rotation support so that the center of gravity of the work and the rotation support is eccentric downward in the vertical direction with respect to the center of rotation, and when the rotation of the work is started, the work is rotated in a predetermined rotation direction. A method for transporting a workpiece, which comprises rotating the workpiece by a predetermined angle in the opposite direction, and then activating a rotational drive means for rotationally driving a rotary support part while the workpiece is inertially rotating in a predetermined rotational direction due to its own weight. 2. A rotating support section for rotatably supporting the workpiece around a substantially horizontal center of rotation is provided on the trolley, a rotational drive means for rotationally driving the rotating support section in a predetermined rotational direction, and a traveling drive for driving the trolley to travel. In a workpiece conveyance device configured to include a means for moving a cart while rotating the workpiece in a predetermined rotational direction via a rotational support section, the rotational support section is configured to rotate the workpiece and the rotational support section in an upright position. Sometimes, the center of gravity is eccentrically downward in the vertical direction with respect to the center of rotation, and the workpiece is rotated by a predetermined angle in the opposite direction to the rotation direction to a position near the upstream position where the rotation of the workpiece starts. 1. A workpiece conveyance device comprising: a rotating means; and a starting means for starting the rotational drive means while the workpiece rotated by the rotating means is rotating in a predetermined rotational direction due to its own weight.