JP2017105420A - Driving wheel unit and automatic conveyance carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a size of a driving wheel unit of an automatic conveyance carrier.SOLUTION: A driving wheel unit 3 is fitted to an automatic conveyance carrier 1 having a carrier body 11 and plural casters 12 which support the carrier body from below, and drives the automatic conveyance carrier. The driving wheel unit comprises: an arm support part 31 which can be fitted to the carrier body; an arm 32 which is so supported as to be rotatable around a fulcrum 311 of the arm support part; a drive wheel 33 which is connected to the arm; a drive mechanism 34 which is connected to the drive wheel and rotationally drives the drive wheel; and an elastic member 35 which is elastically deformed between the arm and the arm support part, and gives a downward force to the drive wheel. A fulcrum of the arm support part fitted to the carrier body is positioned between a top edge and a bottom edge of the drive wheel in a vertical direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a drive wheel unit and an automatic conveyance carriage.

  Conventionally, automatic conveyance carts that are automatically operated by computer control in a production line or the like in a factory have been used. For example, Japanese Patent Laid-Open No. 2000-142452 (Reference 1) discloses an omnidirectional vehicle including a vehicle main body 1, one caster wheel, and drive units 10, 11, 14, and 15 each including a drive wheel. It is disclosed. The drive units 10 and 11 are connected to the vehicle body 1 via the suspension mechanism 9 and the steering shaft 4. The drive units 14 and 15 are connected to the vehicle main body 1 via the suspension mechanism 13 and the steering shaft 7. In the omnidirectional vehicle, the direction of the drive wheels is changed by rotating the steering shaft. In the suspension mechanism, three springs are arranged around each drive wheel, and the drive wheel is supported by the three springs so as to be movable in the vertical direction. Thereby, the four driving wheels are always brought into contact with the traveling surface.

On the other hand, "the insane sense of the car that the expert did not notice, (64) seesaw type suspension that changes the conventional common sense (part 2), [online], September 18, 2013, [November 4, 2015 Search], Internet <URL: http://spring3car.blogspot.jp/2013/09/6.html> (Reference 2) discloses a suspension of a normal car. Document 2 describes an example in which a suspension is provided above each tire, and an example in which a suspension is provided in front of or behind each tire.
Japanese Patent Application Laid-Open No. 2000-142452 (64) Seesaw-type suspension that changes the conventional common sense (Part 2), [online], September 18, 2013, [November 4, 2015 search], Internet <URL: http://spring3car.blogspot.jp/2013/09/6.html>

  By the way, in the omnidirectional vehicle of Document 1, since the driving wheels support most of the weight of the vehicle body 1 and the object to be conveyed, a suspension mechanism for a plurality of driving wheels is caused by the unevenness of the weight of the object to be conveyed. There is a possibility that the spring of the part contracts unevenly and the vehicle body tilts. The same applies to the automobile of Document 2.

  In the omnidirectional vehicle of Document 1, since the driving wheels are arranged away from the steering shaft, there is a limit to the improvement of the steering ability of the vehicle such as in-situ turning. Further, in the omnidirectional vehicle of Document 1, since the three springs are arranged around each drive wheel as described above, the drive unit is enlarged in plan view. Moreover, since the number of parts and assembly man-hours of a drive unit increase, the manufacturing cost of an omnidirectional mobile vehicle increases. On the other hand, in the automobile of Document 2, the suspension is disposed above the wheel, so that the drive unit including the wheel and the suspension is enlarged in the vertical direction.

  The present invention has been made in view of the above problems, and an object thereof is to reduce the size of a drive wheel unit.

  An exemplary drive wheel unit according to an embodiment of the present invention is attached to an automatic conveyance carriage having a carriage main body and a plurality of casters that support the carriage main body from below, and drives the automatic conveyance carriage. To do. The drive wheel unit includes an arm support portion that can be attached to the carriage main body, an arm that is rotatably supported around a fulcrum of the arm support portion, a drive wheel connected to the arm, and the drive wheel. A drive mechanism connected to rotationally drive the drive wheel; and an elastic member that elastically deforms between the arm and the arm support portion and applies a downward force to the drive wheel; The fulcrum of the arm support portion attached to the cart body is located between the upper end and the lower end of the drive wheel in the vertical direction.

  In the present invention, the drive wheel unit can be reduced in size.

FIG. 1 is a bottom view of the automatic conveyance vehicle according to the first embodiment. FIG. 2 is a side view showing a part of the automatic conveyance cart. FIG. 3 is a side view showing a part of the automatic conveyance cart. FIG. 4 is a side view showing a part of the automatic conveyance cart. FIG. 5 is a side view showing a part of the automatic conveyance cart. FIG. 6 is a side view of the drive wheel unit according to the second embodiment. FIG. 7 is a side view of the drive wheel unit according to the third embodiment. FIG. 8 is a side view of the drive wheel unit according to the fourth embodiment. FIG. 9 is a side view of a drive wheel unit according to the fifth embodiment. FIG. 10 is a diagram illustrating another arrangement example of the arm support portion, the arm, the drive wheel, and the elastic member. FIG. 11 is a diagram illustrating another arrangement example of the arm support portion, the arm, the drive wheel, and the elastic member. FIG. 12 is a side view of another drive wheel unit. FIG. 13 is a side view of another drive wheel unit.

  FIG. 1 is a bottom view of an automatic conveyance carriage 1 including a drive wheel unit 3 according to a first embodiment of the present invention. FIG. 2 is a side view showing a part of the automatic conveyance cart 1. In FIG. 2, a part of the configuration of the automatic conveyance cart 1 is shown in cross section. The same applies to FIGS. 3 to 5 described later. FIG. 2 illustrates a state in which a driven wheel 121 of a caster 12 described later and a drive wheel 33 of the drive wheel unit 3 are in contact with a floor surface 91 having substantially the same height.

  The automatic transport cart 1 is used for transporting an object to be transported on a production line in a factory, for example. The automatic conveyance cart 1 is also called an automatic guided vehicle and is automatically operated by computer control, for example. The automatic conveyance vehicle 1 is also called AGV (Automated Guided Vehicle). In the following description, the left-right direction in FIGS. 1 and 2 is referred to as “front-rear direction”, and the up-down direction in FIG. 1 is referred to as “width direction”. In addition, the above-mentioned front-back direction does not necessarily correspond with the moving direction of the automatic conveyance cart 1.

  The automatic conveyance cart 1 includes a cart body 11, a plurality of casters 12, a drive wheel unit 3, and a control unit 4. The cart body 11 is, for example, a substantially flat member. An object to be conveyed that is conveyed by the automatic conveyance carriage 1 is placed on the upper surface of the carriage main body 11. The upper surface of the cart body 11 is substantially parallel to the floor surface 91, for example. The control unit 4 controls the drive wheel unit 3. The control part 4 is attached to the cart main body 11, for example. The control unit 4 may be installed at a position away from the cart body 11.

  The plurality of casters 12 are attached to the cart body 11 and support the cart body 11 from below. In the automatic conveyance carriage 1, the entire weight of the carriage main body 11 and the object to be conveyed is supported by a plurality of casters 12. In the automatic conveyance carriage 1, the drive wheel unit 3 hardly supports the weight of the carriage main body 11 and the object to be conveyed.

  The automatic conveyance cart 1 includes three or more casters 12. The three or more casters 12 are arranged on a non-linear line. In other words, any three casters 12 out of the plurality of casters 12 attached to the cart body 11 constitute a triangular apex. In other words, the plurality of casters 12 includes two casters 12 arranged on a straight line, and one or more casters 12 arranged at positions spaced from the straight line.

  In the example shown in FIG. 1, the automatic conveyance cart 1 includes four casters 12. The four casters 12 are respectively arranged in the vicinity of the four corners of the substantially rectangular cart body 11 in plan view. That is, the four casters 12 form a quadrangular vertex. The two casters 12 adjacent in the width direction are arranged at substantially the same position in the front-rear direction. Each caster 12 is disposed below the cart body 11.

  The caster 12 includes a driven wheel 121 and a driven wheel support portion 122. The driven wheel 121 is supported by a driven wheel support part 122. The driven wheel support part 122 is connected to the lower surface of the cart body 11, for example. The driven wheel 121 is a substantially disc-shaped wheel that rotates around a central axis that faces in the horizontal direction. The driven wheel support portion 122 is, for example, a substantially columnar member that faces the vertical direction. The driven wheel support portion 122 rotates about a central axis that faces the vertical direction, whereby the direction of the driven wheel 121 is changed.

  The driven wheel 121 of the caster 12 rotates as the carriage main body 11 moves by the drive wheel unit 3. Specifically, the driven wheel support portion 122 of the caster 12 rotates so that the central axis of the driven wheel 121 is substantially perpendicular to the moving direction of the carriage body 11. Then, the driven wheel 121 rotates in parallel with the movement direction of the carriage main body 11 as the carriage main body 11 moves.

  The drive wheel unit 3 is attached to the carriage body 11 and drives the automatic conveyance carriage 1. In the example shown in FIG. 1, the automatic conveyance cart 1 includes two drive wheel units 3. The drive wheel unit 3 is located below the cart body 11, for example. In the example shown in FIG. 2, a hole 111 is provided on the lower surface of the carriage body 11 above the drive wheel unit 3. The hole 111 is, for example, a through hole that penetrates the carriage main body 11 in the vertical direction. The upper end of the drive wheel unit 3 is located, for example, in the hole 111 of the carriage main body 11. The hole 111 may be a recess that is recessed upward from the lower surface of the carriage body 11.

  The drive wheel unit 3 includes an arm support portion 31, an arm 32, a drive wheel 33, a drive mechanism 34, and an elastic member 35. The arm support portion 31 is a member that can be attached to the carriage main body 11. In the example shown in FIGS. 1 and 2, the arm support portion 31 is attached to the lower surface of the carriage main body 11 with a bolt or the like, and protrudes downward from the carriage main body 11. The arm 32 is a member extending in a substantially horizontal direction. The arm 32 is supported by the arm support 31 so as to be rotatable about the fulcrum 311 of the arm support 31. For example, a sliding bearing is provided between the arm 32 and the fulcrum 311. The arm support portion 31 includes an elastic member support portion 312 that protrudes to the right side of the fulcrum 311 in the drawing. The elastic member support portion 312 is a substantially rectangular plate-like portion that is substantially parallel to the floor surface 91. A through hole penetrating in the vertical direction is provided in the center of the elastic member support portion 312.

  In the example shown in FIGS. 1 and 2, a drive wheel connecting portion 321 that extends upward from the arm 32 is provided at the left end portion of the arm 32. The drive wheel connecting portion 321 is a substantially rectangular plate-like portion that is substantially perpendicular to the floor surface 91. In addition, a columnar guide portion 322 extending upward from the arm 32 is provided at the right end portion 324 of the arm 32. The guide part 322 is, for example, a bolt that faces substantially in the vertical direction. A lower end portion of the guide portion 322 is fixed to the arm 32. The guide part 322 extends upward of the elastic member support part 312 through the through hole of the elastic member support part 312. The guide portion 322 and the elastic member support portion 312 are not in contact with each other. An elastic member contact portion 323 that comes into contact with the elastic member 35 is provided at the upper end portion of the guide portion 322. The elastic member contact portion 323 is, for example, a plate-like member that extends substantially perpendicular to the guide portion 322.

  The drive wheel 33 is a substantially disc-shaped wheel that rotates around a drive shaft 331 that faces in the width direction. The central axis J1 of the drive shaft 331 is also the central axis of the drive wheel 33. The central axis J1 is substantially parallel to the floor surface 91 and is substantially parallel to the width direction. The direction in which the central axis J1 faces is fixed relative to the carriage main body 11.

  The drive wheel 33 is connected to the arm 32. Specifically, the drive shaft 331 of the drive wheel 33 is connected to the drive wheel connection portion 321. In other words, the drive shaft 331 of the drive wheel 33 is supported by the arm 32 at the drive wheel connection portion 321. The arm 32 extends in the front-rear direction from the lower end of the drive wheel connection portion 321 to the fulcrum 311 of the arm support portion 31. The drive shaft 331 of the drive wheel 33 is supported from below by the arm 32. The upper end of the drive wheel 33 is located in the hole 111 of the carriage body 11. The fulcrum 311 of the arm support portion 31 is located between the upper end and the lower end of the drive wheel 33 in the vertical direction.

  A drive mechanism 34 is disposed on the opposite side of the drive wheel connecting portion 321 from the drive wheel 33. The drive mechanism 34 is also supported from below by the arm 32 via the drive wheel connecting portion 321. The drive mechanism 34 is connected to the drive wheel 33 and rotationally drives the drive wheel 33. Specifically, the drive mechanism 34 is connected to the drive shaft 331 of the drive wheel 33 and rotates the drive wheel 33 by rotating the drive shaft 331. The drive mechanism 34 is, for example, an electric motor.

  The elastic member 35 is disposed along the guide portion 322. The elastic member 35 is, for example, a coil spring that faces in the vertical direction, and the guide portion 322 is located on the radially inner side of the elastic member 35. The elastic member 35 is elastically deformed in the vertical direction along the guide portion 322. The elastic member 35 is disposed in a compressed state between the elastic member support portion 312 of the arm support portion 31 and the elastic member contact portion 323 of the arm 32. The lower end and the upper end of the elastic member 35 are in contact with the elastic member support portion 312 and the elastic member contact portion 323, respectively. The elastic member contact portion 323 that contacts the elastic member 35 is located between the upper end and the lower end of the drive wheel 33 in the vertical direction. The upper end of the guide part 322 is located in the hole part 111 of the cart main body 11, for example.

  The lower end of the elastic member 35 is pressed against the elastic member support portion 312. The lower end of the elastic member 35 is supported by the carriage body 11 via the arm support portion 31. The upper end of the elastic member 35 is pressed against the elastic member contact portion 323 of the guide portion 322. The upper end of the elastic member 35 is in contact with the arm 32 via the guide portion 322. When the guide part 322 is regarded as a part of the arm 32, the upper end of the elastic member 35 comes into contact with the arm 32 at the elastic member contact part 323. In other words, the elastic member 35 is elastically deformed between the arm 32 and the arm support portion 31. In other words, the elastic member 35 is elastically deformed between the carriage main body 11 and the arm 32 via the arm support portion 31. The lower end and the upper end of the elastic member 35 may be connected to the elastic member support portion 312 and the elastic member contact portion 323 by welding or the like, respectively.

  As described above, the elastic member 35 is disposed between the arm 32 and the cart body 11 in a compressed state. Therefore, a moment in the counterclockwise direction in FIG. 2 is applied to the arm 32 around the fulcrum 311 of the arm support portion 31 by the restoring force of the elastic member 35. Thereby, a downward force is applied to the drive wheel 33. As a result, the drive wheel 33 is pressed against the floor surface 91. The force applied to the drive wheel 33 by the restoring force of the elastic member 35 does not necessarily have to be a vertically downward force, and may be a force having a downward component.

  As described above, in the automatic conveyance cart 1, approximately the entire weight of the cart body 11 and the object to be conveyed is supported by the plurality of casters 12. For this reason, the force for pressing the drive wheel 33 against the floor surface 91 by the elastic member 35 only needs to be slightly larger than the rolling resistance of the plurality of casters 12. For this reason, the motive power of the drive mechanism 34 can be made small and it can contribute to the energy-saving of the automatic conveyance trolley | bogie 1. FIG. The force for pressing the driving wheel 33 against the floor surface 91 by the elastic member 35 changes, for example, the vertical position of the nut attached to the guide portion 322, and increases the distance between the elastic member support portion 312 and the elastic member contact portion 323. It can be adjusted by changing. The force pressing the driving wheel 33 against the floor surface 91 by the elastic member 35 may be adjusted by other methods.

  In the example shown in FIG. 2, the fulcrum 311 of the arm support portion 31 is located between the central axis J1 of the drive wheel 33 and the elastic member contact portion 323 of the arm 32 in the horizontal direction. The horizontal distance between the central axis J1 of the drive wheel 33 and the fulcrum 311 of the arm support portion 31 is larger than the horizontal distance between the fulcrum 311 of the arm support portion 31 and the elastic member contact portion 323. In other words, in the longitudinal direction of the arm, which is the direction in which the arm 32 extends, the distance between the center axis J1 of the drive wheel 33 and the fulcrum 311 is greater than the distance between the fulcrum 311 and the elastic member contact portion 323. Preferably, the distance between the central axis J1 of the drive wheel 33 and the fulcrum 311 is 1.5 times or more and 3 times or less the distance between the fulcrum 311 and the elastic member contact portion 323. In the example shown in FIG. 2, the distance between the central axis J1 of the drive wheel 33 and the fulcrum 311 is about twice the distance between the fulcrum 311 and the elastic member contact portion 323.

  3 and 4 are side views showing a part of the automatic conveyance carriage 1. FIG. In FIG. 3, the portion of the floor surface 91 that contacts the driving wheel 33 of the driving wheel unit 3 is recessed below the portion that the driven wheel 121 of the caster 12 contacts. In FIG. 4, the portion of the floor surface 91 that contacts the drive wheel 33 of the drive wheel unit 3 protrudes above the portion of the caster 12 that contacts the driven wheel 121.

  In the state shown in FIG. 3, from the state shown in FIG. 2, the arm 32 rotates about the fulcrum 311 in the counterclockwise direction in the figure, and the right end portion 324 of the arm 32 and the lower end of the guide portion 322 move upward. doing. Further, the right end 324 of the arm 32 is closer to the elastic member support 312 of the arm support 31 than in the state shown in FIG. Thereby, the protrusion length which is the length of the part which protrudes upwards rather than the elastic member support part 312 among the guide parts 322 becomes slightly long, and the elastic member 35 also becomes a little long in the up-down direction. Also in the state shown in FIG. 3, the elastic member 35 is in a compressed state. Therefore, a moment in the counterclockwise direction in FIG. 3 is applied to the arm 32 around the fulcrum 311 of the arm support portion 31 by the restoring force of the elastic member 35. As a result, the drive wheel 33 is pressed against the floor surface 91. Further, the elastic member contact portion 323 that contacts the elastic member 35 is located between the upper end and the lower end of the drive wheel 33 in the vertical direction.

  In the state shown in FIG. 4, from the state shown in FIG. 2, the arm 32 rotates around the fulcrum 311 in the clockwise direction in the figure, and the right end portion 324 of the arm 32 and the lower end of the guide portion 322 move downward. ing. Further, the right end 324 of the arm 32 is farther from the elastic member support 312 of the arm support 31 than in the state shown in FIG. Thereby, the protrusion length which is the length of the part which protrudes upwards rather than the elastic member support part 312 among the guide parts 322 becomes slightly short, and the elastic member 35 also becomes slightly short in the up-down direction. Even in the state shown in FIG. 4, the elastic member 35 is in a compressed state. Therefore, a moment in the counterclockwise direction in FIG. 4 is applied to the arm 32 around the fulcrum 311 of the arm support portion 31 by the restoring force of the elastic member 35. As a result, the drive wheel 33 is pressed against the floor surface 91. Further, the elastic member contact portion 323 that contacts the elastic member 35 is located between the upper end and the lower end of the drive wheel 33 in the vertical direction.

  FIG. 5 is a side view showing a part of the automatic conveyance cart 1. FIG. 5 shows a state in which the driving wheel 33 and the driven wheel 121 are separated from the floor surface by lifting the automatic conveyance cart 1 or the like. In the state shown in FIG. 5, the arm 32 rotates about the fulcrum 311 in the counterclockwise direction in the drawing and the driving wheel 33 moves downward in the state shown in FIG. 3. The right end 324 of the arm 32 moves upward and comes into contact with the elastic member support 312 of the arm support 31. This prevents the arm 32 from rotating in the counterclockwise direction and prevents the drive wheel 33 from moving downward as compared to the state shown in FIG. That is, the right end portion 324 of the arm 32 is a stopper 324 that contacts the arm support portion 31 and restricts the rotation of the arm 32. In other words, the arm 32 includes a stopper 324 that contacts the carriage main body 11 via the arm support portion 31 and restricts the rotation of the arm 32. Even when the stopper 324 of the arm 32 is in contact with the elastic member support portion 312, the elastic member 35 is maintained in a compressed state.

  In the example shown in FIG. 1, the automatic conveyance cart 1 includes two drive wheel units 3. In the following description, when distinguishing between the two drive wheel units 3, the upper drive wheel unit 3 in FIG. 1 is referred to as "first drive wheel unit 3", and the lower drive wheel unit 3 is referred to as "first drive wheel unit 3". This is referred to as “2 drive wheel unit 3”. The “second driving wheel 33” that is the driving wheel 33 of the second driving wheel unit 3 is parallel to the central axis J1 of the “first driving wheel 33” that is the driving wheel 33 of the first driving wheel unit 3. In this direction, the first drive wheel 33 is disposed at a position different from that of the first drive wheel 33 and attached to the carriage main body 11. In the example shown in FIG. 1, the two drive wheel units 3 are arranged apart from each other in the width direction at approximately the same position in the front-rear direction. The two drive wheel units 3 are disposed in the vicinity of the end of the carriage main body 11 in the width direction.

  The first drive wheel unit 3 and the second drive wheel unit 3 are controlled by the control unit 4. The controller 4 controls the rotational speed and direction of the first drive wheel unit 3 and the second drive wheel unit 3, thereby controlling the movement speed and direction of the carriage body 11.

  Specifically, for example, when the first drive wheel 33 and the second drive wheel 33 rotate in the clockwise direction in FIG. 2, the carriage main body 11 moves to the right side in FIG. Further, when the first drive wheel 33 and the second drive wheel 33 rotate in the counterclockwise direction in FIG. 2, the carriage main body 11 moves to the left in FIG. When the cart body 11 moves to the right or left side in FIG. 1, if the rotational speed of one of the first and second drive wheels 33 is lower than the rotational speed of the other drive wheel 33, the cart The main body 11 moves while bending toward the one driving wheel 33.

  Further, for example, the first driving wheel 33 rotates in the clockwise direction in FIG. 2 and the second driving wheel 33 rotates in the counterclockwise direction in FIG. It turns in the clockwise direction in FIG. Further, the first driving wheel 33 rotates in the counterclockwise direction in FIG. 2 and the second driving wheel 33 rotates in the clockwise direction in FIG. Turn counterclockwise inside.

  As described above, the drive wheel unit 3 is attached to the automatic conveyance carriage 1 including the carriage main body 11 and the plurality of casters 12 that support the carriage main body 11 from below, and drives the automatic conveyance carriage 1. . The drive wheel unit 3 includes an arm support portion 31, an arm 32, a drive wheel 33, a drive mechanism 34, and an elastic member 35. The arm support portion 31 can be attached to the cart body 11. The arm 32 is supported so as to be rotatable about a fulcrum 311 of the arm support portion 31. The drive wheel 33 is connected to the arm 32. The drive mechanism 34 is connected to the drive wheel 33 and rotationally drives the drive wheel 33. The elastic member 35 is elastically deformed between the arm 32 and the arm support portion 31 and applies a downward force to the drive wheel 33. A fulcrum 311 of the arm support 31 attached to the carriage body 11 is located between the upper end and the lower end of the drive wheel 33 in the vertical direction.

  As a result, even when the floor surface 91 below the drive wheel 33 is located at a different position in the vertical direction from the floor surface 91 with which the driven wheel 121 contacts, Can be pressed with strength. In other words, the drive wheel 33 can be suitably brought into contact with the floor surface 91 regardless of the position in the vertical direction of the floor surface 91 below the drive wheel 33. As a result, a suitable movement of the automatic conveyance cart 1 by the drive wheel unit 3 can be realized. Further, as described above, since the entire weight of the carriage main body 11 and the object to be conveyed is supported by the plurality of driven wheels 121, the distance between the carriage main body 11 and the floor surface 91 is stably maintained, and the drive wheels 33. Even when the vertical position is changed, it is possible to prevent the vertical position of the carriage body 11 and the tilt relative to the horizontal plane from being changed.

  In the automatic conveyance cart 1, the drive wheel unit 3 can be reduced in size. Specifically, the driving wheel unit 3 is flattened by pressing one driving wheel 33 against the floor surface 91 by one elastic member 35 as compared with the case where the driving wheel is pressed by a plurality of elastic members. It can be reduced in size. Further, by positioning the fulcrum 311 of the arm support portion 31 between the upper end and the lower end of the drive wheel 33 in the vertical direction, the drive wheel unit 3 can be downsized in the vertical direction.

  In the drive wheel unit 3, the elastic member contact portion 323 that contacts the elastic member 35 is positioned between the upper end and the lower end of the drive wheel 33 in the vertical direction. Thereby, the drive wheel unit 3 can be further downsized in the vertical direction. Further, as described above, the fulcrum 311 of the arm support portion 31 is located between the central axis J1 of the drive wheel 33 and the elastic member contact portion 323 that contacts the elastic member 35 in the horizontal direction. Thereby, the relationship between the distance between the central axis J1 of the drive wheel 33 and the fulcrum 311 and the distance between the fulcrum 311 and the elastic member contact portion 323 can be set with a relatively high degree of freedom. Thereby, the restoring force of the elastic member 35 can be easily set to an appropriate magnitude.

  As described above, the distance between the central axis J1 of the drive wheel 33 and the fulcrum 311 of the arm support portion 31 is larger than the distance between the fulcrum 311 of the arm support portion 31 and the elastic member contact portion 323. Thereby, the deformation | transformation of the elastic member 35 accompanying the vertical motion of the drive wheel 33 can be made small. As a result, the restoring force of the elastic member 35 is averaged, and a stable force is applied to the drive wheel 33, so that even when the floor surface 91 is uneven, the variation in the drive force by the drive wheel unit 3 is reduced. Can be suppressed.

  In the drive wheel unit 3, the elastic member 35 is elastically deformed in the vertical direction. Thus, the structure of the drive wheel unit 3 can be simplified by making the deformation direction of the elastic member 35 substantially parallel to the displacement direction of the drive wheel 33. The arm 32 includes a stopper 324 that contacts the arm support portion 31 and restricts the rotation of the arm 32. Thereby, when the driving wheel 33 is separated from the floor surface 91, the driving wheel 33 can be prevented from excessively moving downward. In addition, the position where rotation of the arm 32 is restricted by providing a movable part such as a bolt that can change the downward projection amount at a position where the stopper 324 contacts the lower surface of the elastic member support 312. It can be variable.

  As described above, the arm 32 supports the drive shaft 331 of the drive wheel 33 from below. Thereby, compared with the case where the drive shaft 331 is supported by the arm 32 from above, the drive wheel unit 3 can be further downsized in the vertical direction. Moreover, since interference with the arm 32 and the trolley | bogie main body 11 can be suppressed, the automatic conveyance trolley | bogie 1 can be further reduced in the up-down direction.

  The automatic conveyance cart 1 includes a cart body 11, three or more casters 12, and a drive wheel unit 3. The three or more casters 12 are arranged on a non-straight line and support the cart body 11 from below. The drive wheel unit 3 is attached to the cart body 11. As described above, when the drive wheel unit 3 is downsized in the vertical direction, the automatic conveyance carriage 1 can be downsized in the vertical direction.

  The drive wheel unit 3 is located below the cart body 11. For this reason, when the drive wheel unit 3 is downsized in the vertical direction as described above, the automatic conveyance cart 1 can be further downsized in the vertical direction. Further, the upper end of the drive wheel unit 3 is located in the hole 111 of the carriage body 11. Thereby, the automatic conveyance cart 1 can be further downsized in the vertical direction.

  The automatic conveyance carriage 1 further includes a first drive wheel unit 3, a second drive wheel unit 3, and a control unit 4 that controls the first and second drive wheel units 3. The second drive wheel 33 of the second drive wheel unit 3 is located at a position different from the first drive wheel 33 in the direction parallel to the central axis J1 of the first drive wheel 33 of the first drive wheel unit 3. And is attached to the cart body 11. The control unit 4 controls the moving speed and moving direction of the carriage main body 11 by controlling the rotating speed and rotating direction of the first and second drive wheels 33. Thereby, compared with the automatic conveyance cart having a mechanism for changing the direction of the central axis of the drive wheel, the automatic conveyance cart 1 is moved in various directions at a desired speed while simplifying the structure related to the drive wheel 33. Can do. As described above, in the drive wheel unit 3, the drive wheel 33 can be suitably brought into contact with the floor surface 91. Therefore, the drive wheel unit 3 requires the above-described highly accurate rotation control of the drive wheel 33. It is particularly suitable for the automatic conveyance cart 1.

  FIG. 6 is a side view of the drive wheel unit 3a according to the second embodiment of the present invention. The drive wheel unit 3a is attached to, for example, the automatic conveyance carriage 1 shown in FIG. 1 instead of the drive wheel unit 3 described above, and drives the automatic conveyance carriage 1. In the drive wheel unit 3a, an arm 32a is provided instead of the arm 32 and the elastic member 35 shown in FIG. The other configuration of the drive wheel unit 3a is substantially the same as that of the drive wheel unit 3 shown in FIG.

  As shown in FIG. 6, the drive wheel unit 3a includes an arm support portion 31a, an arm 32a, a drive wheel 33a, and a drive mechanism 34a. The arm support portion 31 a is a member that can be attached to the carriage main body 11. The arm support portion 31 a is attached to the lower surface of the carriage main body 11 with, for example, a bolt and protrudes downward from the carriage main body 11. The arm 32a includes a leaf spring 325a. The right end portion of the leaf spring 325a in the drawing is fixed to the arm support portion 31a via a bolt or the like, for example. In other words, the arm 32a can be indirectly attached to the cart body 11 via the arm support portion 31a. The leaf spring 325a comes into contact with the leaf spring contact portion 313a protruding from the arm support portion 31a substantially in the width direction from below. The leaf spring contact portion 313a is, for example, a substantially cylindrical portion that faces substantially the width direction.

  The leaf spring 325a extends in the substantially front-rear direction from the leaf spring contact portion 313a. A drive wheel connecting portion 321a extending upward from the leaf spring 325a is provided at the left end portion of the leaf spring 325a in the drawing. The drive wheel 33a and the drive mechanism 34a are connected to the drive wheel connection part 321a of the arm 32a. The drive mechanism 34a is connected to the drive wheel 33a and rotationally drives the drive wheel 33a. The drive shaft 331a and the drive mechanism 34a of the drive wheel 33a are supported from below by a leaf spring 325a of the arm 32a.

  The leaf spring 325a is elastically deformed so that the left end is bent upward with the leaf spring contact portion 313a as a fulcrum. In other words, the left end portion of the leaf spring 325a is positioned above the state in which the leaf spring 325a is not elastically deformed. For this reason, a downward force is applied to the drive wheel 33a by the restoring force of the leaf spring 325a. As a result, the drive wheel 33a is pressed against the floor surface 91. The force applied to the drive wheel 33a by the restoring force of the leaf spring 325a does not necessarily need to be a vertically downward force, and may be a force having a downward component. Specifically, the fulcrum of the leaf spring 325a in the arm 32a is a portion that contacts the leaf spring 325a in the leaf spring contact portion 313a. In the example shown in FIG. 6, the fulcrum of the leaf spring 325a is the lower right portion of the leaf spring contact portion 313a.

  As described above, in the automatic conveyance cart 1, approximately the entire weight of the cart body 11 and the object to be conveyed is supported by the plurality of casters 12. For this reason, the force which presses the driving wheel 33a against the floor surface 91 by the leaf spring 325a only needs to be slightly larger than the rolling resistance of the plurality of casters 12. For this reason, the motive power of the drive mechanism 34 can be made small and it can contribute to the energy-saving of the automatic conveyance trolley | bogie 1. FIG.

  As described above, the drive wheel unit 3 a is attached to the automatic conveyance carriage 1 including the carriage main body 11 and the plurality of casters 12 that support the carriage main body 11 from below, and drives the automatic conveyance carriage 1. . The drive wheel unit 3a includes an arm 32a, a drive wheel 33a, and a drive mechanism 34a. The arm 32 a can be attached to the cart body 11. The arm 32a includes a leaf spring 325a. The drive wheel 33a is connected to the arm 32a. The driving wheel 33a is given a downward force by a leaf spring 325a. The drive mechanism 34a is connected to the drive wheel 33a and rotationally drives the drive wheel 33a. The fulcrum of the leaf spring 325a in the arm 32a attached to the carriage body 11 is located between the upper end and the lower end of the drive wheel 33a in the vertical direction.

  Thereby, similarly to the drive wheel unit 3 described above, the drive wheel 33a can be suitably brought into contact with the floor surface 91 regardless of the position in the vertical direction of the floor surface 91 below the drive wheel 33a. As a result, it is possible to realize a suitable movement of the automatic conveyance carriage 1 by the drive wheel unit 3a. Further, as described above, since the entire weight of the carriage main body 11 and the object to be conveyed is supported by the plurality of driven wheels 121, even if the vertical position of the drive wheels 33a is changed, the carriage It is possible to prevent the vertical position of the main body 11 and the inclination with respect to the horizontal plane from being changed.

  In the automatic conveyance cart 1, the drive wheel unit 3a can be reduced in size. Specifically, the driving wheel unit 3a is flattened by pressing one driving wheel 33a against the floor surface 91 with one leaf spring 325a, compared to the case where the driving wheel is pressed by a plurality of elastic members. It can be reduced in size. Further, by positioning the fulcrum of the leaf spring 325a between the upper end and the lower end of the drive wheel 33a in the vertical direction, the drive wheel unit 3a can be downsized in the vertical direction. Furthermore, in the drive wheel unit 3a, the number of parts constituting the drive wheel unit 3a can be reduced by using the leaf spring 325a as the arm 32a, and the drive wheel unit 3a can be reduced in size and weight.

  In the drive wheel unit 3a, the leaf spring 325a may be directly attachable to the carriage main body 11. Moreover, the leaf | plate spring 325a should just be utilized as at least one part of the arm 32a.

  FIG. 7 is a side view of the drive wheel unit 3b according to the third embodiment of the present invention. The drive wheel unit 3b is attached to, for example, the automatic conveyance carriage 1 shown in FIG. 1 instead of the drive wheel unit 3 described above, and drives the automatic conveyance carriage 1. Similarly to the drive wheel unit 3 shown in FIG. 2, the drive wheel unit 3b includes an arm support portion 31b, an arm 32b, a drive wheel 33b, a drive mechanism 34b, and an elastic member 35b.

  In the drive wheel unit 3b, the elastic member support portion 312b of the arm support portion 31b extends to the right side in the drawing relative to the elastic member support portion 312 of the arm support portion 31 shown in FIG. Further, the arm 32b also extends to the right side in the figure than the arm 32 shown in FIG. Furthermore, a screw hole 314b penetrating the elastic member support portion 312b is provided at the right end portion of the elastic member support portion 312b. In other words, the screw hole 314b is provided on the opposite side of the fulcrum 311b across the guide portion 322b. The other configuration of the drive wheel unit 3b is substantially the same as that of the drive wheel unit 3 shown in FIG.

  For example, when an electric motor with an electromagnetic brake is used as the drive mechanism 34b, when the power supply to the drive mechanism 34b is stopped or the electromagnetic brake is released or the like occurs while the electromagnetic brake is operating. Since the driving wheel 33b in contact with the floor surface 91 does not rotate, it becomes difficult for the operator to push and move the automatic conveyance cart 1. Therefore, in the drive wheel unit 3b, when the drive wheel 33b does not rotate normally for some reason, the bolt 51b that is a lifting portion for lifting the drive wheel 33b is inserted into the screw hole 314b of the arm support portion 31b from above. Is done. The bolt 51b is fixed to the arm support portion 31b by screwing into the screw hole 314b. In other words, the screw hole 314b is a fixing portion that fixes the bolt 51b to the arm support portion 31b. The bolt 51b contacts the arm support portion 31b at the screw hole 314b. The bolt 51b is, for example, a hexagon socket head bolt.

  The lower end of the bolt 51b contacts the right end 324b of the arm 32b. When the bolt 51b is tightened, the length of the lower end portion of the bolt 51b protruding downward from the arm support portion 31b becomes longer. In other words, the distance between the contact point between the bolt 51b and the arm support portion 31b and the contact point between the bolt 51b and the arm 32b is increased. Therefore, the right end 324b of the arm 32b is pushed downward, and the arm 32b is rotated clockwise around the fulcrum 311b. As a result, the drive wheel 33b moves upward and is separated from the floor surface 91 upward. As a result, the operator can easily move the automatic transport carriage 1 by pushing it. In the state where the drive wheel 33b is rotating normally, the bolt 51b is not inserted into the screw hole 314b.

  As described above, the drive wheel unit 3b further includes a fixing portion that fixes a lifting portion that applies a force to the arm 32b to lift the drive wheel 33b upward. Thereby, the drive wheel 33b can be maintained in a state of being separated upward from the floor surface 91. As a result, even if the drive wheel 33b does not rotate normally, the automatic conveyance cart 1 can be easily moved.

  In the example shown in FIG. 7, the fixing part is a screw hole 314b provided in the arm support part 31b. The lifting portion is a bolt 51b that contacts the arm 32b and the arm support portion 31b and is fixed to the screw hole 314b. Thereby, the structure which lifts the drive wheel 33b can be simplified. Furthermore, when the drive wheel 33b is rotating normally, the structure of the drive wheel unit 3b can be simplified by removing the bolt 51b from the drive wheel unit 3b.

  The bolt 51b may be fixed to the screw hole 314b even when the drive wheel 33b is rotating normally. In this case, the length of the lower end portion of the bolt 51b protruding downward from the arm support portion 31b is made shorter than that shown in FIG. 7, and as described above, it contacts the right end portion 324b of the arm 32b as a stopper. Then, it may be used as a structure for restricting the rotation of the arm 32b.

  In the drive wheel unit 3b, instead of the screw hole 314b, a through hole having no thread groove is provided, and instead of the bolt 51b, a simple columnar bar member is inserted into the through hole to connect the right end 324b of the arm 32b. The drive wheel 33b may be moved upward by pushing it down. In this case, for example, the bar member and the arm support portion 31b are provided with through holes that overlap each other, and the rod member is fixed to the arm support portion 31b by inserting pins or the like into the two through holes in the overlapped state. May be. The said through-hole provided in the arm support part 31b is a fixing | fixed part which fixes the rod member which is the above-mentioned lifting part.

  FIG. 8 is a side view of the drive wheel unit 3c according to the fourth embodiment of the present invention. The drive wheel unit 3c is attached to, for example, the automatic conveyance carriage 1 shown in FIG. 1 instead of the drive wheel unit 3 described above, and drives the automatic conveyance carriage 1. Similarly to the drive wheel unit 3 shown in FIG. 2, the drive wheel unit 3c includes an arm support portion 31c, an arm 32c, a drive wheel 33c, a drive mechanism 34c, and an elastic member 35c.

  Drive wheel unit 3c further includes a lever 36c, a first locking portion 37c, and a second locking portion 38c. The other configuration of the drive wheel unit 3c is substantially the same as that of the drive wheel unit 3 shown in FIG. The lever 36c is a rod-like member whose end is connected to the arm 32c. In the example shown in FIG. 8, the lever 36 c is a rod-like member extending approximately in the vertical direction. The lower end of the lever 36c is connected to the arm 32c above the fulcrum 311c. The lever 36c may be detachably connected to the arm 32c, or may be fixed to the arm 32c by welding or the like. The first locking portion 37c is a plate-like member that protrudes laterally from the lever 36c. The 1st latching | locking part 37c is connected to the approximate center part of the up-down direction of the lever 36c. The 1st latching | locking part 37c spreads substantially perpendicularly in the width direction. A through hole is provided in the first locking portion 37c. The second locking portion 38c is a plate-like member that protrudes upward from the arm support portion 31c. The second locking portion 38c is connected to the upper end portion of the arm support portion 31c. A through hole is provided in the second locking portion 38c. The 2nd latching | locking part 38c is arrange | positioned in the position shifted | deviated slightly from the 1st latching | locking part 37c regarding the width direction. The 2nd latching | locking part 38c spreads substantially parallel to the 1st latching | locking part 37c. In other words, the main surface of the second locking portion 38c is substantially parallel to the main surface of the first locking portion 37c.

  In the drive wheel unit 3c, when the drive wheel 33c does not rotate normally for some reason, the lever 36c is pushed to the right in the drawing. As a result, the arm 32c is rotated in the clockwise direction in the figure, and the drive wheel 33c moves upward and is separated upward from the floor surface 91. Then, the lever 36c is moved to the right side in the drawing by overlapping the through hole of the first locking portion 37c with the through hole of the second locking portion 38c and inserting a pin or the like into the two through holes in the overlapped state. It is fixed to the arm support portion 31c in an inclined state. Thereby, since the state where the drive wheel 33c is separated from the floor surface 91 is maintained, the operator can easily push the automatic conveyance carriage 1 and move it. In the driving wheel unit 3c, the lever 36c is a lifting portion that lifts the driving wheel 33c upward, and the first locking portion 37c and the second locking portion 38c are fixing portions that fix the lever 36c.

  As described above, the driving wheel unit 3c further includes the first locking portion 37c and the second locking portion 38c that fix the lever 36c that applies a force to the arm 32c to lift the driving wheel 33c upward. Thereby, the drive wheel 33c can be maintained in a state of being separated upward from the floor surface 91. As a result, even if the drive wheel 33c does not rotate normally, the automatic conveyance cart 1 can be easily moved.

  In the drive wheel unit 3c, the lever 36c does not necessarily extend in the vertical direction from the arm 32c. For example, the lever 36c may extend substantially parallel to the floor surface 91 from the arm 32c. In this case, since the lever 36c does not protrude from the upper part of the carriage main body 11, the carrying work of the carriage main body 11 becomes easy.

  FIG. 9 is a side view of a drive wheel unit 3d according to the fifth embodiment of the present invention. The drive wheel unit 3d is attached to, for example, the automatic conveyance carriage 1 shown in FIG. 1 instead of the drive wheel unit 3 described above, and drives the automatic conveyance carriage 1. Similarly to the drive wheel unit 3 shown in FIG. 2, the drive wheel unit 3d includes an arm support 31d, an arm 32d, a drive wheel 33d, a drive mechanism 34d, and an elastic member 35d.

  In the drive wheel unit 3d, the elastic member support portion 312d of the arm support portion 31d extends to the right side in the drawing relative to the elastic member support portion 312 of the arm support portion 31 shown in FIG. Further, the arm 32d also extends to the right side in the figure than the arm 32 shown in FIG. Drive wheel unit 3d further includes a cam 391d, a cam lever -392d, a first locking portion 37d, and a second locking portion 38d. The other configuration of the drive wheel unit 3d is substantially the same as that of the drive wheel unit 3 shown in FIG.

  The cam 391d is a substantially elliptical columnar member that is substantially elliptical in a side view. The cam 391d is disposed between the right end portion of the elastic member support portion 312d and the right end portion 324d of the arm 32d. In other words, the cam 391d is disposed on the opposite side of the fulcrum 311d with the guide portion 322d interposed therebetween. The upper end portion and the lower end portion of the cam 391d are in contact with the arm 32d and the elastic member support portion 312d of the arm support portion 31d. In the state shown in FIG. 9, the minor axis direction of the cam 391d is substantially parallel to the vertical direction. The cam lever -392d is a rod-like member extending substantially in the vertical direction. The lower end portion of the cam lever -392d is connected to the end portion in the width direction of the cam 391d. The first locking portion 37d is a plate-like member that protrudes laterally from the cam lever -392d. The first locking portion 37d is connected to a substantially central portion in the vertical direction of the cam lever -392d. The first locking portion 37d extends substantially perpendicular to the width direction. A through hole is provided in the first locking portion 37d. The second locking portion 38d is a plate-like member connected to the arm support portion 31d. The second locking portion 38d is connected to, for example, the elastic member support portion 312d of the arm support portion 31d. A through hole is provided in the second locking portion 38d. The second locking portion 38d is disposed at a position slightly shifted from the first locking portion 37d in the width direction. The second locking portion 38d extends substantially parallel to the first locking portion 37d. . In other words, the main surface of the second locking portion 38d is substantially parallel to the main surface of the first locking portion 37d.

  In the drive wheel unit 3d, when the drive wheel 33d does not rotate normally for some reason, the cam lever -392d is pushed to the right side in the drawing. As a result, the cam 391d is rotated clockwise in the drawing, and the long diameter portion of the cam 391d is in contact with the arm support portion 31d and the arm 32d. In other words, the distance between the contact point between the cam 391d and the arm support portion 31d and the contact point between the cam 391d and the arm 32d is increased. Therefore, the right end 324d of the arm 32d is pushed downward, the arm 32d rotates clockwise around the fulcrum 311d, and the drive wheel 33d moves upward and separates upward from the floor surface 91. Then, by overlapping the through hole of the first locking portion 37d with the through hole of the second locking portion 38d and inserting a pin or the like into the two through holes in the overlapped state, the cam lever -392d is moved to the right side in the figure. The arm support portion 31d is fixed to the arm support portion 31d in a tilted state. Thereby, since the state where the drive wheels 33d are separated from the floor surface 91 is maintained, the operator can easily move the automatic transport carriage 1 by pushing it. In the drive wheel unit 3d, the cam 391d is a lifting portion that lifts the drive wheel 33d upward, and the first locking portion 37d and the second locking portion 38d are fixing portions that fix the cam 391d. The cam 391d is also a distance changing unit that changes the distance between the arm 32d and the arm support portion 31d.

  As described above, the driving wheel unit 3d further includes the first locking portion 37d and the second locking portion 38d that fix the cam 391d that applies a force to the arm 32d to lift the driving wheel 33d upward. Thereby, the drive wheel 33d can be maintained in a state of being spaced apart from the floor surface 91 upward. As a result, even if the drive wheel 33d does not rotate normally, the automatic conveyance cart 1 can be easily moved.

  In the drive wheel unit 3d, the cam lever -392d does not necessarily extend in the vertical direction from the cam 391d. For example, the cam lever -392d may extend substantially parallel to the floor surface 91 from the cam 391d. In this case, since the cam lever -392d does not protrude from the upper part of the cart body 11, the carrying work of the cart body 11 becomes easy.

  Various changes can be made in the drive wheel units 3 and 3a and the automatic transport carriage 1 described above.

  The number of casters 12 of the automatic conveyance cart 1 may be changed as appropriate. The caster 12 does not necessarily include the substantially disc-shaped driven wheel 121, and may be a so-called ball caster including a ball that rolls on the floor surface 91, for example.

  In the automatic conveyance vehicle 1 shown in FIG. 1, the two drive wheel units 3 do not necessarily have to be arranged at substantially the same position in the front-rear direction. The two drive wheel units 3 may be arranged in various positional relationships unless they are arranged in parallel in the front-rear direction. The same applies when a drive wheel unit 3a is provided instead of the drive wheel unit 3.

  The number of the drive wheel units 3 and 3a included in the automatic conveyance carriage 1 is not necessarily 2 and may be 1 or 3 or more. When the number of drive wheel units 3 and 3a included in the automatic conveyance carriage 1 is 1, for example, a steering shaft for changing the direction of the drive wheel units 3 and 3a is provided. In the automatic conveyance cart 1, the shape of the cart body 11 may be changed as appropriate.

  The upper ends of the drive wheel units 3, 3 a do not necessarily need to be positioned in the hole 111 of the cart body 11, and may be positioned below the lower surface of the cart body 11. It is not always necessary to provide a hole in the lower surface of the cart body 11. The drive wheel units 3 and 3 a are not necessarily arranged below the cart body 11 and may be arranged on the side of the cart body 11.

  The elastic member 35 need not be a coil spring or a leaf spring, and may be a spring having another structure. The elastic member 35 may be a type of elastic member other than a spring.

  The drive shaft 331 of the drive wheel 33 of the drive wheel unit 3 is not necessarily supported from below by the arm 32, and may be supported from the side or from above, for example. The same applies to the drive wheel unit 3a.

  In the drive wheel unit 3, the distance between the center axis J <b> 1 of the drive wheel 33 and the fulcrum 311 of the arm support portion 31 may be equal to or less than the distance between the fulcrum 311 of the arm support portion 31 and the elastic member contact portion 323.

  FIGS. 10 and 11 are diagrams illustrating other preferable arrangement examples of the fulcrum 311 of the arm support portion 31 of the drive wheel unit 3, the arm 32, the drive wheel 33, and the elastic member 35. FIG. In FIGS. 10 and 11, the above-described configurations are simplified. As shown in FIGS. 10 and 11, the fulcrums 311e and 311f of the arm support portions 31e and 31f are not necessarily the same as the center axis J1 of the drive wheels 33e and 33f and the elastic member contact portions 323e and 323f of the arms 32e and 32f in the horizontal direction. There is no need to be between.

  In the example shown in FIG. 10, the center axis J1 of the drive wheel 33e is located between the fulcrum 311e of the arm support portion 31e and the elastic member contact portion 323e of the arm 32e in the horizontal direction. In the example shown in FIG. 11, the elastic member contact portion 323f of the arm 32f is positioned between the fulcrum 311f of the arm support portion 31f and the central axis J1 of the drive wheel 33f in the horizontal direction. Also in the drive wheel units 3e and 3f having the structure shown in FIGS. 10 and 11, similarly to the drive wheel unit 3 described above, the drive wheel 33e regardless of the position in the vertical direction of the floor surface below the drive wheels 33e and 33f. 33f can be suitably brought into contact with the floor surface. As a result, it is possible to realize suitable movement of the automatic conveyance carriage 1 by the drive wheel units 3e and 3f. Further, the drive wheel units 3e and 3f can be reduced in size.

  The elastic member 35 is not necessarily elastically deformed in the vertical direction. For example, as shown in FIG. 12, the elastic member 35g may be elastically deformed in a substantially horizontal direction. In the drive wheel unit 3g shown in FIG. 12, the arm 32g extends in the front-rear direction from the lower end of the drive wheel connection portion 321g provided at the left end portion to the fulcrum 311g of the arm support portion 31g, and extends upward from the fulcrum 311g. . An elastic member contact portion 323g that contacts the left end portion of the elastic member 35g in the drawing is provided at the upper end portion of the arm 32g. The elastic member contact portion 323g is a plate-like member that is substantially perpendicular to the front-rear direction. A through-hole penetrating in the front-rear direction is provided in the center of the elastic member contact portion 323g.

  The guide portion 322g extends in the front-rear direction through the through hole. The left end portion of the guide portion 322g is fixed to the arm support portion 31g. The guide portion 322g extends in the front-rear direction through the through hole of the elastic member contact portion 323g. The guide portion 322g and the elastic member contact portion 323g are not in contact with each other. An elastic member support portion 312g that supports the elastic member 35g is provided at the right end portion of the guide portion 322g.

  The elastic member 35g is disposed along the guide portion 322g. The elastic member 35g is, for example, a coil spring that faces in the front-rear direction, and the guide portion 322g is located on the radially inner side of the elastic member 35g. The elastic member 35g is elastically deformed in the front-rear direction along the guide portion 322g. The elastic member 35g is disposed in a compressed state between the elastic member support portion 312g of the arm support portion 31g and the elastic member contact portion 323g of the arm 32g. The left end and the right end of the elastic member 35g are in contact with the elastic member contact portion 323g and the elastic member support portion 312g, respectively. The elastic member contact portion 323g that contacts the elastic member 35g is located between the upper end and the lower end of the drive wheel 33g in the vertical direction.

  The right end of the elastic member 35g is pressed against the elastic member support portion 312g. The right end of the elastic member 35g is supported by the cart body 11 (not shown) via the guide portion 322g and the arm support portion 31g. The left end of the elastic member 35g is pressed against the elastic member contact portion 323g of the arm 32g. The elastic member 35g is elastically deformed between the arm 32g and the arm support portion 31g. In other words, the elastic member 35g is elastically deformed between the carriage main body 11 and the arm 32g via the arm support portion 31g. The right end and the left end of the elastic member 35g may be connected to the elastic member support portion 312g and the elastic member contact portion 323g, respectively, by welding or the like.

  The elastic member 35g is disposed between the arm 32g and the cart body 11 in a compressed state. For this reason, the arm 32g is given a moment in the counterclockwise direction in FIG. 12 around the fulcrum 311g of the arm support portion 31g by the restoring force of the elastic member 35g. Thereby, a downward force is applied to the drive wheel 33g. As a result, the drive wheel 33g is pressed against the floor surface 91. The force applied to the drive wheel 33g by the restoring force of the elastic member 35g does not necessarily have to be a vertically downward force, and may be a force having a downward component.

  In the drive wheel unit 3g, similarly to the drive wheel unit 3 described above, the drive wheel 33g can be suitably brought into contact with the floor surface 91 regardless of the position in the vertical direction of the floor surface 91 below the drive wheel 33g. . As a result, it is possible to realize a suitable movement of the automatic conveyance carriage 1 by the drive wheel unit 3g. Further, the drive wheel unit 3g can be reduced in size.

  FIG. 13 is a side view showing another preferred example of the drive wheel unit. Similarly to the drive wheel unit 3g shown in FIG. 12, the drive wheel unit 3h shown in FIG. 13 includes an arm support portion 31h, an arm 32h, a drive wheel 33h, a drive mechanism 34h, and an elastic member 35h.

  In the drive wheel unit 3h, the upper end portion of the arm support portion 31h extends to the left in the drawing from the upper end portion of the arm support portion 31h shown in FIG. A through hole 315h penetrating the arm support portion 31h in the vertical direction is provided at the left end portion of the upper end portion of the arm support portion 31h. A screw hole 326h is provided in the arm 32h between the drive mechanism 34h and the fulcrum 311h in the front-rear direction. The screw hole 326h penetrates the arm 32h in the vertical direction. The other configuration of the drive wheel unit 3h is substantially the same as that of the drive wheel unit 3g shown in FIG.

  In the drive wheel unit 3h, when the drive wheel 33h does not rotate normally due to some reason, a bolt 51h that is a lifting part for lifting the drive wheel 33h is inserted into the through hole 315h of the arm support part 31h from above, The arm 32h is inserted into the screw hole 326h from above. The bolt 51h is fixed to the arm 32h by being screwed into the screw hole 326h. In other words, the screw hole 326h is a fixing portion that fixes the bolt 51h to the arm 32h. The head of the bolt 51h is in contact with a portion around the through hole 315h of the arm support portion 31h. The bolt 51h contacts the arm 32h at the screw hole 326h. The bolt 51h is, for example, a hexagon socket head bolt.

  When the bolt 51h is tightened, the distance between the contact point between the bolt 51h and the arm support portion 31h and the contact point between the bolt 51h and the arm 32h is shortened. For this reason, the arm 32h is rotated around the fulcrum 311h in the clockwise direction in the figure. As a result, the drive wheel 33h moves upward and is separated from the floor surface 91 upward. As a result, the operator can easily move the automatic transport carriage 1 by pushing it. In addition, in the state in which the drive wheel 33h is rotating normally, the bolt 51h is not inserted into the screw hole 326h.

  As described above, the drive wheel unit 3h further includes a fixing portion that fixes a lifting portion that applies a force to the arm 32h to lift the drive wheel 33h upward. Thereby, the drive wheel 33h can be maintained in a state of being separated upward from the floor surface 91. As a result, even if the drive wheel 33h does not rotate normally, the automatic conveyance cart 1 can be easily moved.

  In the example shown in FIG. 13, the fixing part is a screw hole 326h provided in the arm 32h. The lifting portion is a bolt 51h that contacts the arm 32h and the arm support portion 31h and is fixed to the screw hole 326h. Thereby, the structure which lifts the drive wheel 33h can be simplified. Furthermore, when the drive wheel 33h is rotating normally, the structure of the drive wheel unit 3h can be simplified by removing the bolt 51h from the drive wheel unit 3h.

  The bolt 51h may be fixed to the screw hole 326h even when the drive wheel 33h is rotating normally. In this case, the bolt 51h is fixed to the screw hole 326h in a state where the head of the bolt 51h is spaced upward from the arm support portion 31h. The bolt 51h may be used as a structure that limits the rotation of the arm 32h when the head of the bolt 51h contacts the arm support portion 31h.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

  The drive wheel unit according to the present invention can be used for various applications. The drive wheel unit is preferably used as a drive wheel unit of an automatic transport carriage that transports an object to be transported.

DESCRIPTION OF SYMBOLS 1 Automatic conveyance trolley 3, 3a-3h Drive wheel unit 4 Control part 11 Bogie main body 12 Caster 31, 31a-31h Arm support part 32, 32a-32h Arm 33, 33a-33h Drive wheel 34, 34a-34d, 34g, 34h Drive mechanism 35, 35b to 35h Elastic member 36c Lever 37c, 37d First locking portion 38c, 38d Second locking portion 51, 51h Bolt 111 hole portion 311, 311b to 311h fulcrum 313, 313a Leaf spring contact portion 314b Screw hole 323, 323a, 323e, 323f, 323g Elastic member contact portion 324, 324b, 324d Stopper 325, 325a Leaf spring 326h Screw hole 331 Drive shaft 391d Cam J1 Central shaft

Claims (17)

A drive wheel unit that is attached to an automatic conveyance carriage having a carriage main body and a plurality of casters that support the carriage main body from below, and drives the automatic conveyance carriage,
An arm support that can be attached to the cart body;
An arm supported rotatably about a fulcrum of the arm support portion;
A drive wheel connected to the arm;
A drive mechanism connected to the drive wheel for rotationally driving the drive wheel;
An elastic member that elastically deforms between the arm and the arm support portion and applies a downward force to the drive wheel;
With
The fulcrum of the arm support portion attached to the cart body is located between the upper end and the lower end of the drive wheel in the vertical direction.   2. The drive wheel unit according to claim 1, wherein an elastic member contact portion that contacts the elastic member is positioned between the upper end and the lower end of the drive wheel in a vertical direction.   3. The drive wheel unit according to claim 1, wherein the fulcrum of the arm support portion is positioned between a central axis of the drive wheel and an elastic member contact portion that contacts the elastic member in a horizontal direction.   The drive wheel unit according to claim 3, wherein a distance between the central axis of the drive wheel and the fulcrum of the arm support is larger than a distance between the fulcrum of the arm support and the elastic member contact part.   The drive wheel unit according to claim 1, wherein the elastic member is elastically deformed in a vertical direction.   The drive wheel unit according to claim 1, wherein the elastic member is elastically deformed in a horizontal direction.   The drive wheel unit according to claim 1, wherein the arm supports a drive shaft of the drive wheel from below.   The drive wheel unit according to any one of claims 1 to 7, wherein the arm includes a stopper that contacts the arm support portion and restricts rotation of the arm.   The drive wheel unit according to any one of claims 1 to 8, further comprising a fixing portion that fixes a lifting portion that applies a force to the arm to lift the drive wheel upward. The fixing part is a screw hole provided in the arm or the arm support part;
The drive wheel unit according to claim 9, wherein the lifting portion is a bolt that contacts the arm and the arm support portion and is fixed to the screw hole.   The drive wheel unit according to claim 9, wherein the lifting portion is a lever connected to the arm.   The drive wheel unit according to claim 9, wherein the lifting portion is a cam that contacts the arm and the arm support portion. A drive wheel unit that is attached to an automatic conveyance carriage having a carriage main body and a plurality of casters that support the carriage main body from below, and drives the automatic conveyance carriage,
An arm that is attachable to the cart body and includes a leaf spring;
A drive wheel connected to the arm and provided with a downward force by the leaf spring;
A drive mechanism connected to the drive wheel for rotationally driving the drive wheel;
With
A fulcrum of the leaf spring in the arm attached to the cart body is located between the upper end and the lower end of the drive wheel in the vertical direction. The cart body,
Three or more casters arranged on a non-linear line and supporting the cart body from below;
The drive wheel unit according to any one of claims 1 to 13, which is attached to the bogie body;
An automatic conveyance cart equipped with.   The automatic conveyance cart according to claim 14, wherein the drive wheel unit is located below the cart body. A hole is provided in the lower surface of the cart body,
The automatic conveyance cart according to claim 14 or 15, wherein an upper end of the drive wheel unit is located in the hole of the cart body. A first drive wheel unit;
A second drive wheel unit;
A control unit for controlling the first and second drive wheel units;
The second drive wheel of the second drive wheel unit is disposed at a position different from the first drive wheel in a direction parallel to the central axis of the first drive wheel of the first drive wheel unit. Being attached to the cart body,
The control unit according to any one of claims 14 to 16, wherein the control unit controls a moving speed and a moving direction of the carriage main body by controlling a rotating speed and a rotating direction of the first and second drive wheels. Automatic transport cart.

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