Slide clutch mechanism

Abstract

This slide clutch mechanism comprises: a base; a shaft rotatably supported by the base; an engaging portion provided at an end portion on one side in the axial direction of the shaft and configured to engage with an engaged portion; and a clutch provided between the base and the shaft. The shaft is movable between a first position where the engaging portion is separated from the engaged portion by a predetermined distance, and a second position where the engaging portion engages with the engaged portion. The clutch allows the base to rotate together with the shaft about the axial center of the shaft when the shaft is located in the first position, and allows the shaft to rotate relative to the base by a predetermined amount of rotational play about the axial center when the shaft is located in the second position.

Description

Sliding clutch mechanism

[0001] The present disclosure relates to a sliding clutch mechanism.

[0002] Patent Document 1 describes a mechanism including a climbing robot having a drive wheel, a shaft inserted into the drive wheel, and a pinion provided at the tip of the shaft, and a rack structure having a rack that engages with the pinion. In this mechanism, the climbing robot moves horizontally when the drive wheel is rotationally driven via the shaft, and moves vertically when the pinion is rotationally driven via the shaft in a state where the pinion engages with the rack.

[0003] In the above mechanism, the shaft moves along the axial direction of the shaft, and when the pinion provided at the tip of the shaft engages with the rack, the climbing robot switches from a state of moving horizontally to a state of moving vertically. When the pinion engages with the rack, by providing rotational play between the drive wheel and the shaft, the rotational angle of the pinion can be finely adjusted via the shaft without rotating the drive wheel. Thereby, the pinion can be easily and surely engaged with the rack.

[0004] Japanese Patent No. 6896034

[0005] In the mechanism as described above, the drive wheel may be fitted to the side surface of the shaft by a ball spline structure. In this case, in order to provide rotational play between the drive wheel and the shaft, it is necessary to provide rotational play between a part of the spline formed on the side surface of the shaft and the balls provided on the inner peripheral surface of the wheel. For this reason, the spline is formed on the side surface of the shaft such that the width of a part of the spline is larger than the width of other parts.

[0006] However, if the width of a portion of the spline on the side of the shaft is made larger than the width of other portions, the manufacturing cost of the shaft may increase, and problems such as reduced durability may occur at the boundary between the portion of the spline and other portions. For these reasons, it is desirable to enable easy and reliable engagement of the pinion with the rack while suppressing the complexity of the shaft structure.

[0007] Therefore, this disclosure describes a slide clutch mechanism that can easily and reliably engage the engaging portion with the engaged portion while suppressing the complexity of the shaft configuration.

[0008] (1) A slide clutch mechanism relating to one aspect of the present disclosure comprises a base, a shaft rotatably supported on the base, a meshing portion provided at one end of the shaft in the axial direction and configured to mesh with a mated portion, and a clutch provided between the base and the shaft, wherein the shaft is movable between a first position where the meshing portion is a predetermined distance away from the mated portion and a second position where the meshing portion meshes with the mated portion, and the clutch allows the base to rotate together with the shaft about the axis of the shaft when the shaft is in the first position, and allows the shaft to rotate relative to the base by a predetermined amount of rotational play about the axis when the shaft is in the second position.

[0009] According to the slide clutch mechanism of (1), when the shaft is in the second position, the clutch allows the shaft to rotate relative to the base by a predetermined amount of rotational play around the shaft's axis. This allows the rotation angle of the meshing part to be finely adjusted by rotating the shaft by a predetermined amount of rotational play without rotating the base when the meshing part engages with the mated part. As a result, the meshing part can be easily and reliably engaged with the mated part. Furthermore, since there is no need to perform special processing on the side surface of the shaft to provide a predetermined amount of rotational play between the base and the shaft, the complexity of the shaft's structure can be suppressed. For example, when the base is spline-fitted to the side surface of the shaft, there is no need to form splines on the side surface of the shaft such that the width of one part of the spline is larger than the width of other parts. This suppresses an increase in the manufacturing cost of the shaft and suppresses the occurrence of problems such as a decrease in durability of the shaft. In summary, according to the slide clutch mechanism of (1), the meshing part can be easily and reliably engaged with the mated part while suppressing the complexity of the shaft's structure.

[0010] (2) In the slide clutch mechanism described in (1) above, the engaged portion may include a rack gear extending along an extending direction intersecting the axial direction, and the meshing portion may include a pinion gear configured to mesh with the rack gear. This configuration allows the pinion gear to be easily and reliably meshed with the rack gear while suppressing the complexity of the shaft configuration.

[0011] (3) In the slide clutch mechanism of (1) or (2) above, the clutch has a first part attached to a base and a second part attached to the shaft so as to be rotatable together with the shaft about the axis of the shaft, wherein the second part is rotatable together with the first part about the axis of the shaft when the shaft is in the first position, and may be rotatable relative to the first part about the axis of the shaft by a predetermined amount of rotational play when the shaft is in the second position. With this configuration, it is possible to specifically realize a configuration in which the meshing part can be easily and reliably engaged with the meshed part while suppressing the complexity of the shaft structure.

[0012] (4) In the slide clutch mechanism described in (3) above, the first part has a groove that opens to one side in the axial direction, and the second part has a main body attached to the shaft and a projection that protrudes from the main body in the radial direction of the shaft and is located in the groove, and when the shaft is in the first position, a first play occurs between the projection and the inner surface of the groove when viewed in the axial direction, and when the shaft is in the second position, a second play occurs between the projection and the inner surface of the groove when viewed in the axial direction, and the first play may be smaller than the second play. With this configuration, a simple clutch can be used to switch between a state in which the base rotates with the shaft and a state in which the base has a predetermined rotational play with respect to the shaft.

[0013] (5) In the slide clutch mechanism described in (4) above, the groove portion includes a tapered groove in the cross-section of the first portion perpendicular to the radial direction, where the width along the circumferential direction of the shaft narrows as it approaches the other side in the axial direction, and the second play may be the play between the inner surface of the tapered groove and the protrusion in the cross-section of the clutch perpendicular to the radial direction. With this configuration, a configuration in which the first play is smaller than the second play can be realized with a groove portion of a simple configuration.

[0014] (6) In the slide clutch mechanism described in (4) above, the protruding portion includes a tapered portion in the cross-section of the second portion perpendicular to the radial direction, where the width along the circumferential direction of the shaft narrows as it approaches the other side in the axial direction, and the second play may be the play between the tapered portion and the inner surface of the groove in the cross-section of the clutch perpendicular to the radial direction. With this configuration, a configuration in which the first play is smaller than the second play can be realized with a protruding portion of a simple configuration.

[0015] (7) In the slide clutch mechanism described in (6) above, the groove portion includes a tapered groove in the cross-section of the first portion perpendicular to the radial direction, where the width along the circumferential direction of the shaft narrows as it approaches the other side in the axial direction, and the first play may be the play between the inner surface of the tapered groove and the tapered portion in the cross-section of the clutch perpendicular to the radial direction. With this configuration, when the shaft is in the first position and rotates with the base around the axis, the contact area between the inner surface of the groove portion and the tapered portion increases compared to the case where the groove portion does not include a tapered groove. This makes it possible to transmit the driving force from the shaft to the base more smoothly.

[0016] (8) In any one of the slide clutch mechanisms described in (3) to (7) above, the second part may be spline-fitted to the outer surface of the shaft. This configuration allows for the realization of a second part that is movable along the axial direction relative to the shaft and rotatable with the shaft about the axis, using a simple structure.

[0017] (9) In any one of the slide clutch mechanisms described in (3) to (8) above, the clutch further includes a biasing part positioned between the first part and the second part, which biases the first part and the second part to move away from each other along the axial direction, and when the shaft is in the first position, the meshing part presses the second part in a direction against the biasing force of the biasing part, so that the second part becomes rotatable together with the first part about the axis, and when the shaft is in the second position, the biasing part biases the first part and the second part to move away from each other by a predetermined distance or more, so that the second part becomes rotatable relative to the first part about the axis by a predetermined amount of rotational play. With this configuration, it is possible to reliably switch between a state in which the base rotates together with the shaft and a state in which the base has a predetermined amount of rotational play between itself and the shaft.

[0018] (10) A transport trolley relating to one aspect of the present disclosure comprises any one of the slide clutch mechanisms described in (1) to (9) above, and a drive device that rotates a shaft around its axis, wherein the base is a drive wheel, and when the shaft is in a first position, the drive wheel rotates to allow movement along the horizontal direction, and when the shaft is in a second position, the meshing portion is rotated by the drive device via the shaft to allow movement along the direction of extension of the meshed portion. Even in such a transport trolley, the meshing portion can be easily and reliably engaged with the meshed portion while suppressing complexity of the shaft configuration.

[0019] (11) In the transport trolley described in (10) above, the drive wheels may be rotationally driven by a drive device via the shaft and clutch when the shaft is in the second position. With this configuration, the drive wheels and the meshing parts can be rotationally driven by a common drive device.

[0020] According to one aspect of this disclosure, the meshing portion can be easily and reliably engaged with the mated portion while suppressing the complexity of the shaft's structure.

[0021] Figure 1 is a front view showing an automated warehouse equipped with a transport trolley having a slide clutch mechanism according to one embodiment of the present disclosure. Figure 2 is a side view of the transport trolley shown in Figure 1. Figure 3 is a perspective view showing the transport trolley positioned on the horizontal rail shown in Figure 1. Figure 4 is a cross-sectional view of the lifting rail shown in Figure 1, cut in a horizontal cross-section. Figure 5 is a perspective view showing the intersection of the lifting rail and the horizontal rail. Figure 6 is a perspective view showing the transport trolley rising on the lifting rail. Figure 7(a) is a perspective view showing the slide clutch mechanism and drive unit when the transport trolley is traveling on the horizontal rail, and Figure 7(b) is a perspective view showing the slide clutch mechanism and drive unit when the transport trolley is moving to another floor. Figure 8(a) is a cross-sectional view of the slide clutch mechanism and drive unit along the line A-A shown in Figure 7(a), and Figure 8(b) is a cross-sectional view of the slide clutch mechanism and drive unit along the line B-B shown in Figure 7(b). Figure 9 is a cross-sectional view showing the cross-section of drive shafts intersecting in the axial direction. Figure 10(a) is an enlarged view of the clutch shown in the perspective cross-sectional view of the slide clutch mechanism along line A-A shown in Figure 7(a), and Figure 10(b) is an enlarged view of the clutch shown in the perspective cross-sectional view of the slide clutch mechanism along line B-B shown in Figure 7(b). Figure 11(a) is a perspective view showing a bush, one of the components of the clutch, Figure 11(b) is a perspective view showing a slider, one of the components of the clutch, and Figure 11(c) is a perspective view showing a hub, one of the components of the clutch. Figure 12 is a perspective view showing a second clutch section, one of the components of the clutch. Figure 13(a) is a front view showing the slide clutch mechanism when the transport trolley is traveling on a horizontal rail, and Figure 13(b) is a front view showing the slide clutch mechanism when the transport trolley is moving to another floor. Figure 14(a) is a perspective view showing the clutch when the transport trolley travels on a horizontal rail, and Figure 14(b) is a front view showing the clutch when the transport trolley moves to another floor.Figure 15(a) is a schematic cross-sectional view along the line C-C shown in Figure 14(a), Figure 15(b) is a schematic cross-sectional view along the line D-D shown in Figure 14(b), Figures 15(c) and 15(d) are cross-sectional views showing the groove formed in the first part and the protrusion in the second part of the slide clutch mechanism according to the first modified example, and Figures 15(e) and 15(f) are cross-sectional views showing the groove formed in the first part and the protrusion in the second part of the slide clutch mechanism according to the second modified example. Figure 16(a) is a perspective view showing a transport trolley and a station equipped with a slide clutch mechanism according to the third modified example, and Figure 16(b) is a schematic front view showing the slide clutch mechanism according to the third modified example.

[0022] The embodiments will be described in detail below with reference to the drawings. In the description of each figure, the same or corresponding parts will be denoted by the same reference numerals, and redundant explanations may be omitted. In the drawings, for the sake of explanation, each configuration of the embodiment will be shown with an appropriate change in scale. Some drawings also show the XYZ Cartesian coordinate system. In the following description, this coordinate system will be referred to for ease of explanation. Hereinafter, the direction along the horizontal plane will be referred to as the X direction, the direction perpendicular to the X direction and along the horizontal plane will be referred to as the Y direction, and the vertical direction will be referred to as the Z direction.

[0023] First, the overall configuration of the automated warehouse 1 will be described with reference to Figure 1. As shown in Figure 1, the automated warehouse 1 comprises a rack structure 2 having a plurality of racks 3, and a plurality of transport trolleys 30 for transporting goods T stored in each storage shelf of the plurality of racks 3. The rack structure 2 is formed by connecting long steel members, etc., that extend in the X, Y, and Z directions, respectively. The automated warehouse 1, for example, has four racks 3 arranged in the Y direction. Each rack 3 has a left rack and a right rack (not shown) that face each other in the Y direction and extend in the X direction. A horizontal travel space Sh is formed between the left rack and the right rack, on which the plurality of transport trolleys 30 travel. Each of the left rack and the right rack has a plurality of storage shelves (or storage racks) provided across multiple levels. Each storage shelf of the rack 3 is capable of storing (or accommodating) goods T.

[0024] The configuration of rack structures 2 and racks 3 can be appropriately changed depending on the required storage capacity and volume of goods T, and the size of the available installation space. The automated warehouse 1 may be equipped with four or more racks 3 (i.e., four or more pairs of left and right racks) to store a larger amount of goods T. When a large number of racks 3 are provided, they are arranged in the Y direction. The automated warehouse 1 may also be equipped with only one rack 3 (i.e., only a left rack and a right rack). Furthermore, transport trolleys 30 traveling in two adjacent horizontal travel spaces Sh in the Y direction may share racks and storage shelves placed between them. In the example shown in Figure 1, each rack 3 has six vertical levels, but the number of levels can also be appropriately changed and set.

[0025] The automated warehouse 1 is installed, for example, on the floor surface F inside a building. The automated warehouse 1 comprises a plurality of (for example, six) picking stations 100 arranged outside the rack structure 2 (a plurality of racks 3). For example, three picking stations 100 are arranged adjacent to one end of the rack structure 2 in the X direction. At each picking station 100, predetermined picking is performed by a worker or a picking robot (work robot), etc.

[0026] The automated warehouse 1 is equipped with a controller 6 that comprehensively controls the transport of goods T by each transport cart 30. The controller 6 can communicate with terminals (operation unit, operation panel, etc.) provided at all transport carts 30 and each picking station 100 via wired or wireless communication means. The controller 6 is a computer that includes, for example, a processor such as a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory).

[0027] The automated warehouse 1 includes an receiving station (not shown). For example, the receiving station is located outside the rack structure 2 (multiple racks 3) and in a different area from the picking station 100. In the automated warehouse 1, the goods T are, for example, containers (also called totes, etc.) that hold multiple goods. The goods T stored in the racks 3 via the receiving station are transported and released by transport carts 30 in response to requests from each picking station 100, or under control by the controller 6. After picking at each picking station 100, the goods T are transported and stored by transport carts 30, or (if the container is empty) are transported to the receiving station as empty containers.

[0028] Each transport cart 30 is an autonomous mobile robot. In the automated warehouse 1, each transport cart 30 can travel horizontally and vertically (up and down) independently within the rack 3. This eliminates the need for conveyors and lifts to deliver goods T to each picking station 100 in the automated warehouse 1. The functions of the transport carts 30 enable the storage, transport, sorting, and picking of goods T in the automated warehouse 1. Furthermore, since the rack 3 and picking stations 100 are modularized, they can be expanded (added) according to the required capacity. The number of transport carts 30 operating in the automated warehouse 1 can also be expanded (added) in the same way. The transport carts 30 are compatible with, for example, refrigerated and frozen environments, and can realize storage environments with multiple temperature zones such as ambient temperature, chilled, and frozen on each level of the rack 3.

[0029] As shown in Figure 1, the rack structure 2 (automated warehouse 1) comprises a plurality of horizontal travel rails 10 arranged adjacent to the rack 3, and a plurality of lifting rails 20 extending vertically within the rack 3. The horizontal travel rails 10 extend in the X direction at each level of the rack 3. A pair of horizontal travel rails 10 extend parallel to each other and spaced apart in the Y direction, corresponding to a pair of drive wheels 41 of a transport trolley 30, which will be described later (see Figure 3). Within the rack 3, a horizontal travel space Sh extends in the X direction, having the area between the pair of horizontal travel rails 10 as its bottom surface and having a predetermined height (cross-sectional area) that allows the transport trolley 30 to pass through. Each transport trolley 30 travels horizontally on the horizontal travel rails 10 in the horizontal travel direction Dh1. The horizontal travel direction Dh1 is parallel to the X direction.

[0030] The lifting rails 20 are provided, for example, at multiple locations in the X direction within the rack 3. In the example shown in Figure 1, for example, two lifting rails 20 are incorporated into the rack 3. Each lifting rail 20 includes, for example, a first lifting rail 21 and a second lifting rail 22 spaced a predetermined distance apart in the X direction. In Figure 1, part of the rack 3 is omitted from the illustration so that the pair of lifting rails 21 and 22 can be easily identified. The first lifting rail 21 and the second lifting rail 22 each extend in the Z direction so as to penetrate all levels of the rack 3. Each transport cart 30 moves up and down (up and down) in the vertical travel direction Dv on the first lifting rail 21 or the second lifting rail 22. The vertical travel direction Dv is parallel to the Z direction.

[0031] Furthermore, in the explanation that "each transport cart 30 rises and falls on the lifting rail," "on the lifting rail" does not mean that each transport cart 30 is positioned "on" the lifting rail relative to gravity (or the vertical direction), but rather that at least a part of the transport cart 30 is in contact with the lifting rail as it rises and falls. "Each transport cart 30 rises and falls on the lifting rail" is synonymous with "each transport cart 30 rises and falls along the lifting rail."

[0032] Next, referring to Figure 2, the configuration of the transport trolley 30 will be explained, and referring to Figures 3 to 5, the structure related to the movement of the transport trolley 30 will be explained. Figure 2 is a side view of the transport trolley 30. The transport trolley 30 can travel in any direction by forward and reverse rotation of the drive wheels 41, so there is no particular concept of front and rear. In the following explanation, the side on which the housing 35 and the information communication unit 39 are provided will be called the rear, and the opposite side will be called the front. The transport trolley 30 includes a flat base portion 31 and a housing 35 provided on the base portion 31. A trolley controller (not shown) that controls the movement of the transport trolley 30 is provided inside the housing 35. The trolley controller communicates information with the controller 6 to cause the transport trolley 30 to transport the cargo T.

[0033] The transport trolley 30 includes a pair of drive wheels 41 mounted slightly rearward of the base portion 31, and, for example, two pairs of support wheels 33 mounted in front of the base portion 31. The transport trolley 30 includes four guide rollers 34 located at the four corners of the base portion 31 and rotatable about a vertical axis. The transport trolley 30 further includes a pair of lower counter wheels 72 and a pair of lifting pinions 71 mounted coaxially with the drive shaft 42 of the drive wheels 41, and a pair of upper counter wheels 37 having an upper counter shaft 37a located above the drive shaft 42. The drive shaft 42 of the drive wheels 41, the rotation axis of the support wheels 33, and the upper counter shaft 37a of the upper counter wheels 37 are parallel to each other and extend horizontally in the width direction of the base portion 31.

[0034] The drive wheels 41 are driven by a drive motor (not shown) and rotate in either forward or reverse direction. The left and right drive wheels 41 may be driven by a single common drive motor, or by two separate drive motors. On the other hand, the lifting pinion 71 is driven by the drive motor of the drive wheels 41 and rotates in either forward or reverse direction. The lower counter wheel 72 and the lifting pinion 71 are mounted on the drive shaft 42. The lifting pinion 71 rotates with the drive motor of the drive wheels 41, but its axial position is controlled by another motor (not shown). The lower counter wheel 72 also moves axially with the lifting pinion 71, but the lower counter wheel 72 is mounted on the drive shaft 42 via a bearing and rotates freely independently of the rotation of the drive wheels 41 and the lifting pinion 71. The upper counter wheel 37 (upper counter shaft 37a) also has its axial position controlled by another motor (not shown), similar to the lower counter wheel 72. The lower counter wheel 72, the lifting pinion 71, and the upper counter wheel 37 move axially in synchronous motion. The mechanical interlocking of these components is achieved using known mechanical elements.

[0035] A retaining frame 31a is provided in front of the base portion 31. In the transport trolley 30, both sides of the retaining frame 31a in the width direction are open so that the load T can pass through in the width direction (horizontal direction perpendicular to the direction of travel, i.e., left and right direction). This allows the load T to be transferred (moved) by sliding it between the retaining space C of the retaining frame 31a and both the left rack and the right rack.

[0036] Figure 3 is a perspective view showing a transport trolley 30 positioned on a horizontal rail 10. As shown in Figure 3, the transport trolley 30 travels in the horizontal direction Dh1 with a pair of drive wheels 41 and two pairs of support wheels 33 resting on a pair of running surfaces 10a of the horizontal rail 10. The horizontal rail 10 has an L-shaped cross-section. The four guide rollers 34 of the transport trolley 30 contact the vertical walls of the horizontal rail 10, thereby maintaining the correct position of the transport trolley 30 in the width direction.

[0037] Next, the lifting rail 20 will be described. Figure 4 is a cross-sectional view of the lifting rail 20 cut in a horizontal cross-section. Figure 5 is a perspective view showing the intersection of the lifting rail 20 and the horizontal running rail 10. In the following detailed description of the structure of the lifting rail 20, only the first lifting rail 21 will be described. The structure of the second lifting rail 22 is the same as that of the first lifting rail 21, so redundant explanations regarding the second lifting rail 22 will be omitted.

[0038] As shown in Figures 4 and 5, the first lifting rail 21 includes a lifting frame 23 having a U-shaped cross-section fixed to the vertical wall of the horizontal travel rail 10, and a pair of holding guide members 24 fixed within the lifting frame 23 and facing each other in the X direction. The lifting frame 23 is open in the Y direction toward the horizontal travel space Sh. A rail gap 11 is formed in the horizontal travel rail 10 so as to coincide with the position of the open portion of the lifting frame 23. In other words, from a broad perspective, the horizontal travel rail 10 and the lifting rail 20 intersect at a right angle, but from a finer perspective, the horizontal travel rail 10 is interrupted at the intersection with the first lifting rail 21 (lifting rail 20). This rail gap 11 allows the drive shaft 42 and the upper counter shaft 37a to pass through when the transport trolley 30 is raised and lowered.

[0039] On the surface of one of the retaining guide members 24, a rack gear 26 extending in the Z direction and a groove 24a adjacent to the rack gear 26 in the Y direction are provided. The rack gear 26 includes a linear gear that meshes with the lifting pinion 71. The position of the rack gear 26 corresponds to the position of the advanced lifting pinion 71 in the width direction (Y direction) of the transport trolley 30. At that time, the position of the groove 24a corresponds to the positions of the advanced lower counter wheel 72 and upper counter wheel 37, respectively, in the width direction (Y direction) of the transport trolley 30.

[0040] Figure 6 is a perspective view showing a transport trolley 30 rising on a lifting rail. The transport trolley 30 can always know its own position while traveling on the horizontal travel rail 10. The trolley controller of the transport trolley 30 sequentially acquires detection values ​​from encoders provided, for example, on the drive motor of the drive wheels 41, and based on the acquired detection values, it determines its own position within the rack 3 (on the horizontal travel rail 10). When the transport trolley 30 moves to another floor, for example to an upper floor, it stops at the position of the first lifting rail 21 (lifting rail 20). Then, the lifting pinion 71, lower counter wheel 72, and upper counter wheel 37 are advanced, and the drive wheels 41 etc. are retracted by another motor etc.

[0041] The lower counter wheel 72 and the upper counter wheel 37 pass through the notches 23a (see Figure 5) formed in the lifting frame 23. The lifting pinion 71 engages with the rack gear 26, and the lower counter wheel 72 and the upper counter wheel 37 fit into the grooves 24a. The drive wheels 41 retract to a position inward in the width direction from the running surface 10a of the horizontal running rail 10. In this state, the transport trolley 30 rises along the first lifting rail 21 by rotating the lifting pinion 71. When the transport trolley 30 moves to a lower level, it descends along the first lifting rail 21 by rotating the lifting pinion 71 in the reverse direction.

[0042] The position of the center of gravity of the transport trolley 30 differs depending on whether the transport trolley 30 is holding a load T on the holding frame 31a or not. The position of the center of gravity of the transport trolley 30 also differs depending on the weight of the load T. The lower counter wheels 72 and upper counter wheels 37, which are arranged in the vertical direction, support the transport trolley 30 on a pair of first lifting rails 21 in a cantilevered state as shown in Figure 6, and the lifting pinion 71 and rack gear 26 mesh securely. This generates the propulsive force for raising and lowering the transport trolley 30.

[0043] The transport cart 30 can turn and travel horizontally on a flat surface such as the floor surface F. For example, a pair of left and right drive wheels 41 can be independently driven. By rotating one of the drive wheels 41 forward and the other drive wheel 41 backward, the direction of the transport cart 30 can be changed. Furthermore, by creating a speed difference between the left and right drive wheels 41, the transport cart 30 can also change its direction while traveling.

[0044] The above-described transport cart 30 includes a slide clutch mechanism 40 and a drive device 50. Hereinafter, referring to FIGS. 7(a), 7(b), 8(a) and 8(b), the slide clutch mechanism 40 and the drive device 50 according to the embodiment will be described in detail. FIG. 7(a) is a perspective view showing the slide clutch mechanism 40 and the drive device 50 when the transport cart 30 travels on the horizontal travel rail 10. FIG. 7(b) is a perspective view showing the slide clutch mechanism 40 and the drive device 50 when the transport cart 30 moves to another floor. FIG. 8(a) is a cross-sectional view of the slide clutch mechanism 40 and the drive device 50 taken along the line A-A shown in FIG. 7(a). FIG. 8(b) is a cross-sectional view of the slide clutch mechanism 40 and the drive device 50 taken along the line B-B shown in FIG. 7(b).

[0045] The slide clutch mechanism 40 has a function of providing rotational play between the drive wheel 41 and the drive shaft 42 when the lifting pinion 71 meshes with the rack gear 26. Thereby, the rotation angle of the lifting pinion 71 can be finely adjusted without rotating the drive wheel 41, so that the lifting pinion 71 can be easily and reliably meshed with the rack gear 26. The drive device 50 rotationally drives the drive shaft 42 around the axial direction D1 described later. That is, the drive device 50 rotationally drives the drive shaft 42 around the axis of the drive shaft 42. Hereinafter, "rotating around the axial direction D1" corresponds to "rotating around the axis of the drive shaft 42".

[0046] The slide clutch mechanism 40 includes a drive wheel (base) 41, a drive shaft (shaft) 42, and a clutch 60. Hereinafter, the axial direction (Y direction) of the drive shaft 42 is defined as the axial direction D1, the radial direction of the drive shaft 42 is defined as the radial direction D2, and the circumferential direction of the drive shaft 42 is defined as the circumferential direction D3.

[0047] The drive shaft 42 extends along the axial direction D1. The drive shaft 42 is formed, for example, in a substantially cylindrical shape. The drive shaft 42 is formed, for example, of metal. The drive shaft 42 is movable (slidable) along the axial direction D1. FIG. 9 is a cross-sectional view showing a cross-section of the drive shaft 42 intersecting the axial direction D1. In the example shown in FIG. 9, on the side surface 42a (outer peripheral surface) of the drive shaft 42, a spline 42b for engagement with the clutch 60 is formed. The spline 42b extends along the axial direction D1 (see FIGS. 8(a) and 8(b)). In the present embodiment, for example, two splines 42b are formed on the side surface 42a of the drive shaft 42. Note that the number of splines 42b is not limited to two. For example, it is sufficient if the number of splines 42b formed on the side surface 42a of the drive shaft 42 corresponds to the number of splines 91d formed on the inner peripheral surface 91c of the main body portion 91 in the second clutch portion 90 described later (see FIG. 12). As an example, it is sufficient if at least one or more splines 42b are formed on the side surface 42a of the drive shaft 42.

[0048] The drive wheel 41 is provided, for example, coaxially with the drive shaft 42. The drive wheel 41 is rotatably supported on the drive shaft 42, for example, via the clutch 60. That is, the drive shaft 42 is rotatably supported by the drive wheel 41. The drive wheel 41 is movable relative to the drive shaft 42 along the axial direction D1. The drive wheel 41 has a wheel 41a and a tire 41b. The wheel 41a is rotatably supported on the drive shaft 42, for example, via the clutch 60. The wheel 41a is formed, for example, in a substantially annular shape. The wheel 41a is formed, for example, of metal. The tire 41b extends so as to surround the outer periphery of the wheel 41a. The tire 41b is formed, for example, in a substantially annular shape. The tire 41b is formed, for example, of resin.

[0049] The clutch 60 is provided between the drive shaft 42 and the drive wheel 41. For example, the clutch 60 is provided between the drive shaft 42 and the wheel 41a of the drive wheel 41 (see Figure 13). In the example shown in Figures 8(a) and 8(b), the clutch 60 has a first portion 61, a second portion 62, and a biasing portion 63.

[0050] The first part 61 and the second part 62 will be described in detail with reference to Figures 10(a) and 10(b). Figure 10(a) is an enlarged view of the clutch 60 shown in the perspective cross-sectional view of the slide clutch mechanism 40 along line A-A shown in Figure 7(a). Figure 10(b) is an enlarged view of the clutch 60 shown in the perspective cross-sectional view of the slide clutch mechanism 40 along line B-B shown in Figure 7(b).

[0051] The first part 61 is attached to the drive wheel 41. The first part 61 includes a bush 64, a slider 65, a hub 66, and a first clutch portion 80. The bush 64, slider 65, and hub 66 are arranged in this order along the radial direction D2. The bush 64 is arranged around the drive shaft 42. In other words, the drive shaft 42 is inserted inside the bush 64. Figure 11(a) is a perspective view showing the bush 64. The bush 64 is movable relative to the drive shaft 42 along the axial direction D1. The bush 64 is made of, for example, resin or metal. The bush 64 has a body portion 64a and a flange portion 64b. The body portion 64a and the flange portion 64b are arranged in this order from one side along the axial direction D1. The body portion 64a is formed, for example, in a substantially cylindrical shape. The flange portion 64b is formed, for example, in an annular shape. The flange portion 64b is attached to the inner circumferential surface of the main body portion 65b of the slider 65, which will be described later.

[0052] The slider 65 is positioned around the bush 64. The slider 65 is movable with the bush 64 relative to the drive shaft 42 along the axial direction D1. The slider 65 is formed of, for example, resin or metal. Figure 11(b) is a perspective view showing the slider 65. As shown in Figure 11(b), the slider 65 has a flange portion 65a and a body portion 65b. The flange portion 65a and the body portion 65b are arranged in this order from one side in the axial direction D1. The body portion 65b is positioned around the bush 64 and is mounted to the bush 64. The body portion 65b is formed, for example, in a substantially cylindrical shape.

[0053] The flange portion 65a is formed, for example, in the shape of a rectangular plate. The flange portion 65a has a first recess 65c that opens on one side in the axial direction D1. The first recess 65c is formed, for example, in a substantially circular shape when viewed in the axial direction D1. The open end of the main body portion 65b is located on the bottom surface 65d of the first recess 65c. The bottom surface 65d extends so as to surround the open end of the main body portion 65b and is formed, for example, in a substantially annular shape.

[0054] The hub 66 is positioned around the slider 65. The hub 66 is movable with the slider 65 relative to the drive shaft 42 along the axial direction D1. The hub 66 is formed of, for example, resin or metal. Figure 11(c) is a perspective view showing the hub 66. The hub 66 has a flange portion 66a and a body portion 66b. The flange portion 66a and the body portion 66b are arranged in this order from one side in the axial direction D1. The body portion 66b is positioned around the body portion 65b of the slider 65. The body portion 66b is formed, for example, in a substantially cylindrical shape.

[0055] The flange portion 66a is formed, for example, in a disc shape. The flange portion 66a has a second recess 66c that opens on one side in the axial direction D1. The shape of the second recess 66c corresponds to the shape of the flange portion 65a of the slider 65. For example, the second recess 66c is formed in a substantially rectangular shape when viewed in the axial direction D1. The bottom surface 66d of the second recess 66c is located at the open end of the main body portion 66b. The bottom surface 66d extends so as to surround the open end of the main body portion 66b. When the main body portion 65b of the slider 65 is positioned inside the main body portion 66b, the flange portion 65a of the slider 65 fits into the second recess 66c of the flange portion 66a (see Figures 10(a) and 10(b)).

[0056] As shown in Figures 10(a) and 10(b), the first clutch portion 80 is located inside the wheel 41a, on one side in the axial direction D1 relative to the slider 65 and hub 66 described above. The first clutch portion 80 is formed of a metal or sintered material, such as aluminum die-cast. The first clutch portion 80 has a main body portion 81 and a retaining plate 82. The main body portion 81 has a plate portion 81a and a surrounding portion 81b. The plate portion 81a is formed integrally with the wheel 41a. The plate portion 81a is formed, for example, in a substantially annular shape. The surrounding portion 81b is positioned on one side in the axial direction D1 relative to the plate portion 81a.

[0057] The main body portion 81 has a hole 81c and two grooves 81d (see Figures 13(a) and 13(b)). The hole 81c penetrates the main body portion 81 (for example, both the plate portion 81a and the surrounding portion 81b) along the axial direction D1. The hole 81c is formed, for example, in a substantially circular shape. Each of the two grooves 81d extends along the radial direction D2. The main body portion 81 has two grooves 81d, but is not limited to this. For example, the number of grooves 81d formed in the first clutch portion 80 may correspond to the number of protrusions 92 that the second clutch portion 90 has (see Figure 12). As an example, the first clutch portion 80 may have at least one groove 81d.

[0058] The retaining plate 82 is attached, for example, to the plate portion 81a of the main body portion 81. The retaining plate 82 is positioned on one side of the main body portion 81 in the axial direction D1. The retaining plate 82 is positioned around the drive shaft 42. The retaining plate 82 extends to cover the hole portion 81c when viewed in the axial direction D1. The retaining plate 82 is formed, for example, in a substantially annular shape. The retaining plate 82 is formed of, for example, resin or metal.

[0059] As described above, the bush 64 is attached to the main body 65b of the slider 65. The main body 65b of the slider 65 is attached to the main body 66b of the hub 66. The slider 65 and the hub 66 are attached to the plate portion 81a of the main body 81 of the first clutch portion 80 (see Figures 10(a) and 10(b)). In this way, the bush 64, slider 65, hub 66 and the first clutch portion 80 are integrated. The first portion 61, for example, with the bush 64, slider 65, hub 66 and the first clutch portion 80 integrated, is rotatable with the drive wheel 41 about the axial direction D1 and is movable along the axial direction D1 with respect to the drive shaft 42 together with the drive wheel 41.

[0060] The second part 62 is attached to the drive shaft 42. The second part 62 has a second clutch portion 90. The second clutch portion 90 is attached to the drive shaft 42. The second clutch portion 90 is formed of a metal or sintered material, such as aluminum die-cast. Figure 12 is a perspective view showing the second clutch portion 90. As shown in Figure 12, the second clutch portion 90 has a main body portion 91 attached to the drive shaft 42 and two protrusions 92 that protrude radially D2 from the main body portion 91.

[0061] The main body 91 is arranged around the drive shaft 42 (see Figures 10(a) and 10(b)). The main body 91 is formed, for example, in a stepped cylindrical shape. The main body 91 is made of, for example, metal or resin. More specifically, the main body 91 has an inner circumferential portion 91a and an outer circumferential portion 91b.

[0062] The inner circumferential portion 91a is spline-fitted to the side surface 42a of the drive shaft 42. Two splines 91d are formed on the inner circumferential surface 91c of the inner circumferential portion 91a. Each spline 91d fits onto each spline 42b of the drive shaft 42, thereby spline-fitting the inner circumferential portion 91a to the drive shaft 42. In other words, the second portion 62 is spline-fitted to the side surface 42a of the drive shaft 42.

[0063] The outer circumferential portion 91b is provided around the inner circumferential portion 91a. The inner circumferential portion 91a protrudes from the outer circumferential portion 91b to the other side in the axial direction D1. This allows for space to be provided between the outer circumferential portion 91b and the bottom surface 65d for arranging the biasing portion 63, which will be described later, as shown in Figures 10(a) and 10(b). For example, even when the inner circumferential portion 91a is in contact with the bottom surface 65d, space to arrange the biasing portion 63 can be provided between the outer circumferential portion 91b and the bottom surface 65d (for example, if the biasing portion 63 is a spring, the minimum length of the spring can be secured).

[0064] Each projection 92 protrudes radially D2 from the side surface 91e of the outer peripheral portion 91b. Each projection 92 is formed of, for example, metal or resin. Each projection 92 has a first surface 92a, a second surface 92b, and a pair of side surfaces 92c. The first surface 92a and the second surface 92b are aligned along the axial direction D1. The first surface 92a and the second surface 92b extend in a direction intersecting the axial direction D1. The pair of side surfaces 92c are aligned along the circumferential direction D3. The pair of side surfaces 92c extend in a direction intersecting the circumferential direction D3. The pair of side surfaces 92c connect the first surface 92a and the second surface 92b. The second clutch portion 90 had two projections 92, but is not limited to this. For example, the number of projections 92 in the second clutch portion 90 may correspond to the number of grooves 81d formed in the first clutch portion 80 (see Figure 13). For example, the second clutch portion 90 may have at least one or more protruding portions 92.

[0065] The main body 91 and each protruding part 92 will be described in detail with reference to Figures 13(a), 13(b), 14(a), 14(b), 15(a), and 15(b). Figure 13(a) is a front view showing the slide clutch mechanism 40 when the transport trolley 30 is traveling on the horizontal rail 10. Figure 13(b) is a front view showing the slide clutch mechanism 40 when the transport trolley 30 is moving to another floor. Figure 14(a) is a perspective view showing the clutch 60 when the transport trolley 30 is traveling on the horizontal rail 10. Figure 14(b) is a front view showing the clutch 60 when the transport trolley 30 is moving to another floor. Figure 15(a) is a schematic cross-sectional view along the line C-C shown in Figure 14(a). Figure 15(b) is a schematic cross-sectional view along the line D-D shown in Figure 14(b). Note that the retaining plate 82 is not shown in Figures 14(a), 14(b), 15(a), and 15(b).

[0066] As shown in Figures 13(a) and 13(b), the second clutch portion 90 is located within the hole 81c and the two grooves 81d of the first clutch portion 80. More specifically, the inner circumferential portion 91a of the main body portion 91 extends from within the hole 81c to within the first recess 65c of the slider 65 (see Figures 10(a) and 10(b)). The outer circumferential portion 91b of the main body portion 91 is located within the hole 81c. Each projection 92 is located within each groove 81d of the first clutch portion 80. Each projection 92 is located between the main body portion 81 and the retaining plate 82 of the first clutch portion 80 (see Figures 10(a) and 10(b)).

[0067] As shown in Figures 14(a) and 14(b), each groove 81d opens to one side in the axial direction D1. Each groove 81d has a depth along the axial direction D1. As shown in Figures 15(a) and 15(b), each groove 81d is composed of a first groove T1 and a second groove T2. The first groove T1 and the second groove T2 are aligned along the axial direction D1. Each of the first groove T1 and the second groove T2 extends along the radial direction D2 (see Figures 14(a) and 14(b)).

[0068] The first groove T1 is a tapered groove whose width along the circumferential direction D3 narrows as it approaches the second groove T2 (as it approaches the other side in the axial direction D1). That is, in the cross-section of the first portion 61 perpendicular to the radial direction D2, the width of the first groove T1 narrows as it approaches the other side in the axial direction D1. For example, the first groove T1 has a pair of tapered surfaces T11 that extend so as to intersect the circumferential direction D3. The pair of tapered surfaces T11 are inclined so as to approach the second groove T2. The second groove T2 is continuous with the other end of the first groove T1 in the axial direction D1. The width of the second groove T2 along the circumferential direction D3 is approximately constant. The second groove T2 has a bottom surface T21 and a pair of side surfaces T22. The bottom surface T21 extends so as to intersect the axial direction D1. The pair of side surfaces T22 are aligned along the circumferential direction D3. The pair of side surfaces T22 extend so as to intersect the circumferential direction D3.

[0069] As shown in Figures 10(a) and 10(b), the biasing portion 63 is positioned between the first portion 61 and the second portion 62. For example, the biasing portion 63 is positioned between the bottom surface 65d of the first recess 65c of the slider 65 of the first portion 61 and the outer peripheral portion 91b of the main body 91 of the second clutch portion 90 of the second portion 62. The biasing portion 63 is positioned around the inner peripheral portion 91a of the main body 91. The biasing portion 63 extends from within the hole 81c of the first clutch portion 80 of the first portion 61 into the first recess 65c of the slider 65 of the first portion 61. The biasing portion 63 biases the first portion 61 and the second portion 62 to move away from each other along the axial direction D1. For example, the biasing portion 63 biases the slider 65 of the first portion 61 and the second clutch portion 90 of the second portion 62 to move away from each other along the axial direction D1. The biasing section 63 is composed of, for example, one spring, but may be composed of multiple springs. In this case, the multiple springs may be arranged to surround the drive shaft 42 with the axial direction D1 as the center.

[0070] The second portion 62 described above is rotatable with the drive shaft 42 about the axial direction D1. The second portion 62 is movable along the axial direction D1 relative to the drive shaft 42. For example, the main body 91 of the second clutch portion 90 of the second portion 62 is movable along the axial direction D1 between the retaining plate 82 of the first portion 61 and the plate portion 81a of the first portion 61. The protruding portion 92 of the second clutch portion 90 of the second portion 62 is movable along the axial direction D1 between the retaining plate 82 of the first portion 61 and the slider 65 of the first portion 61.

[0071] Refer again to Figures 8(a) and 8(b). The slide clutch mechanism 40 further comprises a holding portion 43 and a meshing portion 70. The holding portion 43 holds the drive wheel 41 and the drive shaft 42 via the clutch 60. For example, the holding portion 43 has an arm portion 43a and a bearing portion 43b provided on the arm portion 43a. The arm portion 43a holds the clutch 60 so that it can rotate about the axial direction D1 via the bearing portion 43b. The bearing portion 43b is, for example, an annular bearing (for example, a cross roller bearing).

[0072] The meshing portion 70 includes a lifting pinion 71 (pinion gear), a lower counter wheel 72, and a collar 73. The lifting pinion 71, the lower counter wheel 72, and the collar 73 are arranged in this order from one side in the axial direction D1. The lifting pinion 71 is provided at one end 42c of the drive shaft 42 in the axial direction D1. The lifting pinion 71 is configured to mesh with a rack gear 26 (mesh portion) that extends along the Z direction (extension direction intersecting the axial direction D1). The lower counter wheel 72 is mounted so as to be rotatable relative to the drive shaft 42. The collar 73 is mounted on the drive shaft 42. The collar 73 can press the main body 91 of the second clutch portion 90 to the other side in the axial direction D1 (in the direction against the biasing force of the biasing portion 63) (see Figure 10(a)).

[0073] Next, the operation of the slide clutch mechanism 40 will be described. First, the drive shaft 42 is movable between a first position P1 and a second position P2. In Figures 7(a), 8(a), 10(a), 13(a), 14(a), and 15(a), the drive shaft 42 is located at the first position P1, where the lifting pinion 71 is a predetermined distance from the rack gear 26. The predetermined distance is the distance along the axial direction D1 between the lifting pinion 71 and the rack gear 26 when the lifting pinion 71 is not engaged with the rack gear 26. The transport trolley 30 described above is movable along the X direction (horizontal direction (for example, the direction of travel)) by the rotational drive of the drive wheels 41 when the drive shaft 42 is located at the first position P1. When the drive shaft 42 is located at the second position P2, the drive wheels 41 are rotationally driven by the drive device 50 via the drive shaft 42 and the clutch 60.

[0074] In Figures 7(b), 8(b), 10(b), 13(b), 14(b), and 15(b), the drive shaft 42 is positioned at the second position P2, where the lifting pinion 71 engages with the rack gear 26. When the drive shaft 42 is positioned at the second position P2, the transport trolley 30 described above is movable along the Z direction (the direction in which the rack gear 26 extends) by the rotational drive of the drive device 50 via the drive shaft 42, which drives the meshing portion 70.

[0075] The clutch 60 allows the drive wheel 41 to rotate together with the drive shaft 42 about the axial direction D1 when the drive shaft 42 is in the first position P1. For example, the clutch 60 prevents the drive wheel 41 from rotating relative to the drive shaft 42. More specifically, the second portion 62 of the clutch 60 is rotatable together with the first portion 61 of the clutch 60 about the axial direction D1 when the drive shaft 42 is in the first position P1. As shown in Figures 14(a) and 15(a), when the drive shaft 42 is in the first position P1, the second surface 92b of the projection 92 contacts the bottom surface T21 of the groove 81d.

[0076] When the drive shaft 42 is in the first position P1, a first play occurs between the protrusion 92 and the side surface T22 (inner surface) of the second groove T2 of the groove 81d when viewed in the axial direction D1. This first play is the gap between the inner surface of the groove 81d and the protrusion 92 in the cross-section of the clutch 60 perpendicular to the radial direction D2, for example, the gap between each side surface T22 of the second groove T2 of the groove 81d and each side surface 92c of the protrusion 92. As an example, there is almost no such first play between the protrusion 92 and the inner surface of the groove 81d. Therefore, when the drive shaft 42 is in the first position P1, and the second part 62 rotates together with the drive shaft 42, the first clutch part 80 of the first part 61 rotates together with the protrusion 92 of the second clutch part 90 of the second part 62. In this case, the drive wheel 41 to which the first part 61 is attached also rotates.

[0077] The clutch 60 allows the drive shaft 42 to rotate relative to the drive wheel 41 by a predetermined amount of rotational play around the axial direction D1 when the drive shaft 42 is in the second position P2. For example, the clutch 60 allows the drive wheel 41 to rotate relative to the drive shaft 42 by a predetermined amount of rotational play. More specifically, the second part 62 of the clutch 60 is rotatable relative to the first part 61 by a predetermined amount of rotational play around the axial direction D1 when the drive shaft 42 is in the second position P2. "A predetermined amount of rotational play" means "only by an angle less than or equal to a predetermined angle around the axial direction D1." The predetermined angle is set so that the rotation angle of the lifting pinion 71 can be finely adjusted so that the lifting pinion 71 engages with the rack gear 26 without rotating the drive wheel 41. For example, when the drive shaft 42 is rotated by a predetermined angle, it is sufficient that it can move a distance greater than or equal to the width along the circumferential direction D3 of the teeth included in the lifting pinion 71 and the width along the circumferential direction D3 of the teeth included in the rack gear 26. The predetermined angle may be determined, for example, in relation to the number of teeth in the lifting pinion 71, for example, (360 degrees / number of teeth in the lifting pinion 71) ± α°. α is a constant that indicates the pitch of the teeth in the lifting pinion 71.

[0078] As shown in Figures 14(b) and 15(b), when the drive shaft 42 is in the second position P2, a second amount of play occurs between the projection 92 and the tapered surface T11 (inner surface) of the first groove T1 of the groove 81d when viewed in the axial direction D1. The second amount of play is the gap between the inner surface of the groove 81d and the projection 92 in the cross-section of the clutch 60 perpendicular to the radial direction D2, for example, the gap between the inner surface of the first groove T1 of the groove 81d and each side surface 92c of the projection 92. As an example, such a second amount of play is greater than the first amount of play. That is, the first amount of play is less than the second amount of play. Therefore, when the drive shaft 42 is in the second position P2, the second part 62 can rotate by a predetermined amount of rotational play without the first part 61 rotating. Therefore, it is possible to rotate the drive shaft 42 to which the second part 62 is attached by a predetermined amount of rotational play without rotating the drive wheel 41 to which the first part 61 is attached.

[0079] As shown in Figures 10(a) and 10(b), when the drive shaft 42 moves from the second position P2 (the position corresponding to Figure 10(b)) to the first position P1 (the position corresponding to Figure 10(a)), the meshing portion 70 moves to the other side in the axial direction D1 and presses against the second portion 62 of the clutch 60. More specifically, the meshing portion 70 presses against the second portion 62 in a direction that opposes the biasing force of the biasing portion 63 when the drive shaft 42 is in the first position P1. For example, when the drive shaft 42 is in the first position P1, the collar 73 of the meshing portion 70 moves to the other side in the axial direction D1 and presses against the main body 91 of the second clutch portion 90 of the second portion 62. As a result, the collar 73 pushes the second clutch portion 90 side to the other side in the axial direction D1, and each projection 92 enters the second groove T2 from the first groove T1 and engages with the second groove T2. As a result, the second part 62 becomes rotatable together with the first part 61 about the axial direction D1 when the drive shaft 42 is in the first position P1. In other words, the slide clutch mechanism 40 is in a state where the clutch 60 is closed (the clutch 60 is engaged).

[0080] When the drive shaft 42 moves from the first position P1 (the position corresponding to Figure 10(a)) to the second position P2 (the position corresponding to Figure 10(b)), the biasing unit 63 moves the second portion 62 of the clutch 60 to one side in the axial direction D1. More specifically, when the drive shaft 42 is in the second position P2, the biasing unit 63 biases the first portion 61 and the second portion 62 so that they are separated from each other by a predetermined distance or more. For example, when the drive shaft 42 is in the second position P2, the collar 73 releases the pressure on the second portion 62 to the other side in the axial direction D1. In this case, as the second portion 62 is pressed and moved to one side in the axial direction D1 by the biasing unit 63, each protrusion 92 retracts from the second groove T2, and a second play is created between each protrusion 92 and the inner surface of the first groove T1. As a result, the second portion 62 becomes rotatable relative to the first portion 61 by a predetermined amount of rotational play around the axial direction D1. In other words, the slide clutch mechanism 40 is in the state where the clutch 60 is open (the clutch 60 is disengaged).

[0081] Furthermore, when the biasing portion 63 presses the second portion 62 to one side in the axial direction D1 and moves it, the second portion 62 comes into contact with the retaining plate 82 and stops. As a result, the projection 92 of the second clutch portion 90 in the second portion 62 is maintained in a state where it is located within the groove 81d of the main body portion 81 of the first clutch portion 80 in the first portion 61. Consequently, after each projection 92 has exited each second groove T2, the collar 73 makes it possible to re-enter each projection 92 into the second groove T2. In other words, the slide clutch mechanism 40 can switch between a state where the clutch 60 is engaged and a state where the clutch 60 is disengaged by moving the drive shaft 42 along the axial direction D1.

[0082] The following describes the effects and benefits of the slide clutch mechanism 40 according to this embodiment. First, conventionally, in order to provide rotational play between the drive wheel and the drive shaft, it was necessary to provide rotational play between a portion of the spline formed on the side surface of the drive shaft and a ball provided on the inner circumferential surface of the drive wheel. For this reason, the spline was formed such that the width of a portion of the spline was larger than the width of other portions on the side surface of the shaft. However, when the width of a portion of the spline is made larger than the width of other portions on the side surface of the drive shaft, the manufacturing cost of the drive shaft may increase. For example, after forming the spline so that the width of a portion of it is larger than the width of other portions, heat treatment (hardening) is required to manufacture the drive shaft with high precision, thus increasing the manufacturing cost of the drive shaft. Also, for example, bearing parts (e.g., slide ball bearings) are required on the drive unit side and the drive wheel side, thus increasing the cost of manufacturing the slide clutch mechanism.

[0083] Furthermore, if the width of a portion of the spline on the side of the drive shaft is larger than the width of other portions, there is a risk of problems such as reduced durability occurring at the boundary between the portion of the spline and other portions. For example, when widening a portion of the spline, the axis of the drive shaft shifts, which puts a load on the outer diameter of the spline and drive shaft, causing problems such as wear and failure. Also, for example, if heat treatment is performed on the drive shaft after forming a spline on the side of the drive shaft, a hard layer is formed on the side of the drive shaft. If the width of a portion of the spline is formed to be larger than the width of other portions, the hard layer is worn away at the boundary between the portion of the spline and other portions, exposing the soft layer to the outside of the drive shaft. This makes the boundary more susceptible to wear (for example, when bearing balls move within the spline along the axial direction of the drive shaft, the balls collide with the boundary, causing wear), and the durability of the drive shaft is reduced. Also, for example, if a spline is formed on the side of the drive shaft and the width of a portion of the spline is formed to be larger than the width of other portions, and then heat treatment is performed on the drive shaft, the drive shaft will become distorted. Therefore, it was technically difficult to manufacture the drive shaft with high precision.

[0084] In contrast, according to the slide clutch mechanism 40 of the embodiment, when the drive shaft 42 is in the second position P2, the clutch 60 allows the drive shaft 42 to rotate relative to the drive wheel 41 by a predetermined amount of rotational play around the axial direction D1. As a result, when the meshing portion 70 engages with the rack gear 26, the rotation angle of the meshing portion 70 can be finely adjusted by rotating the drive shaft 42 by a predetermined amount of rotational play without rotating the drive wheel 41. As a result, the meshing portion 70 can be easily and reliably engaged with the rack gear 26. Furthermore, since there is no need to perform special processing on the side surface 42a of the drive shaft 42 in order to provide a predetermined amount of rotational play between the drive wheel 41 and the drive shaft 42, the complexity of the drive shaft 42's structure can be suppressed. For example, when the drive wheel is spline-fitted to the side surface of the drive shaft, there is no need to form a spline on the side surface of the drive shaft such that the width of one part of the spline is larger than the width of other parts. As a result, the manufacturing cost of the drive shaft 42 can be suppressed, and problems such as reduced durability in the drive shaft 42 can be suppressed. As described above, the slide clutch mechanism 40 allows the meshing portion 70 to be easily and reliably engaged with the rack gear 26 while suppressing the complexity of the drive shaft 42's configuration.

[0085] More specifically, according to the slide clutch mechanism 40 of the embodiment, the structure of the drive shaft 42 is simplified, eliminating wobble in the drive shaft 42 and improving the durability of the drive shaft 42. Furthermore, since it is not necessary to provide a specially shaped spline on the side surface 42a of the drive shaft 42, a general-purpose drive shaft can be used as the drive shaft 42 of the slide clutch mechanism 40. In addition, since bearing parts (for example, slide ball bearings) are not required on the drive device 50 side and the drive wheel 41 side, the manufacturing cost of the slide clutch mechanism 40 can be reduced.

[0086] In the slide clutch mechanism 40, the rack gear 26 is a rack gear that extends along the Z direction (extension direction intersecting the axial direction D1). The meshing portion 70 includes a lifting pinion 71 configured to mesh with the rack gear 26. This allows the lifting pinion 71 to easily and reliably mesh with the rack gear 26 while suppressing the complexity of the drive shaft 42 configuration.

[0087] In the slide clutch mechanism 40, the clutch 60 has a first portion 61 attached to the drive wheel 41 and a second portion 62 attached to the drive shaft 42 so as to be rotatable together with the drive wheel 41 about an axial direction D1. The second portion 62 is rotatable together with the first portion 61 about an axial direction D1 when the drive shaft 42 is in a first position P1, and is rotatable relative to the first portion 61 by a predetermined amount of rotational play about an axial direction D1 when the drive shaft 42 is in a second position P2. This makes it possible to specifically realize a configuration in which the lifting pinion 71 can be easily and reliably engaged with the rack gear 26 while suppressing the complexity of the drive shaft 42's structure.

[0088] In the slide clutch mechanism 40, the first part 61 has a groove 81d that opens to one side in the axial direction D1, and the second part 62 has a main body 91 attached to the drive shaft 42 and a protruding part 92 that protrudes radially D2 from the main body 91 and is located in the groove 81d. When the drive shaft 42 is in the first position P1, a first play occurs between the protruding part 92 and the inner surface of the groove 81d when viewed in the axial direction D1, and when the drive shaft 42 is in the second position P2, a second play occurs between the protruding part 92 and the inner surface of the groove 81d when viewed in the axial direction D1, and the first play may be smaller than the second play. With this configuration, a simple clutch 60 can switch between a state in which the drive wheel 41 rotates together with the drive shaft 42 and a state in which the drive wheel 41 has a predetermined rotational play between itself and the drive shaft 42.

[0089] In the slide clutch mechanism 40, the groove portion 81d includes a first groove T1 in the cross-section of the first portion 61 perpendicular to the radial direction D2, where the width along the circumferential direction D3 of the drive shaft 42 narrows as it approaches the other side in the axial direction D1, and the second play is the play between the inner surface of the first groove T1 and the protrusion 92 in the cross-section of the clutch 60 perpendicular to the radial direction D2. As a result, a configuration in which the first play is smaller than the second play can be realized with a simple groove portion 81d.

[0090] In the slide clutch mechanism 40, the second portion 62 is spline-fitted to the side surface 42a of the drive shaft 42. This allows for the realization of a second portion 62 that is movable along the axial direction D1 relative to the drive shaft 42 and rotatable together with the drive shaft 42 about the axial direction D1, with a simple configuration.

[0091] In the slide clutch mechanism 40, the clutch 60 is positioned between a first portion 61 and a second portion 62 and has a biasing portion 63 that biases the first portion 61 and the second portion 62 to move away from each other along the axial direction D1. When the drive shaft 42 is in the first position P1, the meshing portion 70 presses the second portion 62 in a direction opposite to the biasing force of the biasing portion 63, so that the second portion 62 becomes rotatable together with the first portion 61 about the axial direction D1. When the drive shaft 42 is in the second position P2, the biasing portion 63 biases the first portion 61 and the second portion 62 to move away from each other by a predetermined distance or more, so that the second portion 62 becomes rotatable relative to the first portion 61 by a predetermined amount of rotational play about the axial direction D1. This makes it possible to reliably switch between a state in which the drive wheel 41 rotates together with the drive shaft 42 and a state in which the drive wheel 41 has a predetermined amount of rotational play between itself and the drive shaft 42.

[0092] The transport trolley 30 according to this embodiment includes a slide clutch mechanism 40 and a drive device 50 that rotates the drive shaft 42 around the axial direction D1. When the drive shaft 42 is in a first position P1, the drive wheels 41 are rotated, allowing movement along the X direction. When the drive shaft 42 is in a second position P2, the meshing portion 70 is rotated by the drive device 50 via the drive shaft 42, allowing movement along the Z direction. Even in such a transport trolley 30, the configuration of the drive shaft 42 is kept from becoming overly complex, while the lifting pinion 71 can be easily and reliably meshed with the rack gear 26.

[0093] In the transport trolley 30, the drive wheels 41 are rotationally driven by the drive unit 50 via the drive shaft 42 and clutch 60 when the drive shaft 42 is in the second position P2. This allows the drive wheels 41 and the lifting pinion 71 to be rotationally driven by a common drive unit 50.

[0094] While embodiments have been described above, one aspect of this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the disclosure.

[0095] Figures 15(c) and 15(d) are cross-sectional views showing a groove 181d formed in the first portion 61 and a protrusion 192 of the second portion 62 in the slide clutch mechanism 40 according to the first modified example. The slide clutch mechanism 40 according to the first modified example differs from the slide clutch mechanism 40 according to the above embodiment in that a groove 181d is formed in the first portion 61 instead of a groove 81d, and the second clutch portion 90 of the second portion 62 has a protrusion 192 instead of a protrusion 92.

[0096] Each groove 181d differs from each groove 81d in that it is composed only of the second groove T2. Each projection 192 differs from each projection 92 in that it has a tapered portion 192d. The tapered portion 192d extends from the side surface 92c to the second surface 92b. In the cross-section of the second portion 62 perpendicular to the radial direction D2, the width of the tapered portion 192d along the circumferential direction D3 narrows as it approaches the other side in the axial direction D1.

[0097] The first play is the play between the inner surface of the groove 181d and the projection 192 in the cross-section of the clutch 60 perpendicular to the radial direction D2, for example, the gap between each side T22 of the second groove T2 of the groove 181d and each side 92c of the projection 192. The second play is the play between the tapered portion 192d and the inner surface of the groove 181d in the cross-section of the clutch 60 perpendicular to the radial direction D2, for example, the gap between the tapered portion 192d of the projection 92 and each side T22 of the second groove T2 of the groove 181d.

[0098] In the slide clutch mechanism 40 according to the first modified example, the protrusion 192 includes a tapered portion 192d in the cross-section of the second portion 62 perpendicular to the radial direction D2, where the width along the circumferential direction D3 of the drive shaft 42 narrows as it approaches the other side in the axial direction D1, and the second play is the play between the tapered portion 192d and the side surface T22 of the groove portion 181d in the cross-section of the clutch 60 perpendicular to the radial direction D2. As a result, a configuration in which the first play is smaller than the second play can be realized with a simple protrusion 192.

[0099] Figures 15(e) and 15(f) show the groove 281d formed in the first portion 61 and the protrusion 192 of the second portion 62 in the slide clutch mechanism 40 according to the second modified example. The slide clutch mechanism 40 according to the second modified example differs from the slide clutch mechanism 40 according to the above embodiment in that the groove 281d is formed in the first portion 61 instead of the groove 81d, and the second clutch portion 90 of the second portion 62 has a protrusion 192 instead of a protrusion 92.

[0100] Each groove 281d differs from each groove 81d in that it has only a second groove T102 and a third groove T103. The width of the second groove T102 along the circumferential direction D3 is substantially constant. The second groove T102 has a pair of side surfaces T122. The pair of side surfaces T122 are aligned along the circumferential direction D3. The pair of side surfaces T122 extend so as to intersect the circumferential direction D3.

[0101] The third groove T103 is continuous with the other end of the second groove T102 in the axial direction D1. The third groove T103 is a tapered groove whose width along the circumferential direction D3 narrows as it moves away from the second groove T102 (as it approaches the other side in the axial direction D1). The third groove T103 has a bottom surface T131 and a pair of tapered surfaces T132. The bottom surface T131 extends so as to intersect the axial direction D1. The pair of tapered surfaces T132 are aligned along the circumferential direction D3. Each of the pair of tapered surfaces T132 is continuous with each of the pair of side surfaces T122 of the second groove T102. Each of the pair of tapered surfaces T132 is inclined so as it approaches the other side in the axial direction D1, it approaches the bottom surface T131. In this case, when the drive shaft 42 is in the first position P1, the bottom surface 192b of the protrusion 192 contacts the bottom surface T131 of the groove 281d.

[0102] The first play is the gap between the inner surface of the third groove T103 and the tapered portion 192d in the cross-section of the clutch 60 perpendicular to the radial direction D2. For example, the first play is the gap between each tapered surface T132 of the third groove T103 of the groove portion 281d and the tapered portion 192d, or the gap between each side surface T122 of the second groove T102 of the groove portion 281d and the protruding portion 192. The second play is the gap between the tapered portion 192d and the inner surface of the groove portion 181d in the cross-section of the clutch 60 perpendicular to the radial direction D2. For example, the second play is the gap between each side surface T122 of the second groove T102 of the groove portion 281d and the tapered portion 192d.

[0103] In the slide clutch mechanism 40 according to the second modified example, the groove 281d includes a third groove T103 in the cross-section of the first portion 61 perpendicular to the radial direction D2, the width along the circumferential direction D3 narrows as it approaches the other side in the axial direction D1, and the first play is the play between the inner surface of the third groove T103 and the tapered portion 192d in the cross-section of the clutch 60 perpendicular to the radial direction D2. As a result, when the drive shaft 42 is in the first position P1 and rotates together with the drive wheel 41 about the axial direction D1, the contact area between the inner surface of the groove 281d and the tapered portion 192d increases compared to the case where the groove does not include a tapered groove. This allows the driving force to be transmitted more smoothly from the drive shaft 42 to the drive wheel 41.

[0104] In the above embodiments and their respective modifications, the slide clutch mechanism 40 was a mechanism provided in the transport trolley 30, which is a climbing robot, but it is not limited to this. The slide clutch mechanism 40 may also be a mechanism provided in the transport trolley 130, which is an AGV (Automatic Guided Vehicle). Figure 16(a) is a perspective view showing the transport trolley 130 equipped with the slide clutch mechanism 140 according to the third modification and the conveyor station S. Figure 16(b) is a schematic front view showing the slide clutch mechanism 140 according to the third modification. In Figure 16(a), the color 73 is not shown.

[0105] The transport trolley 130 includes a slide clutch mechanism 140 and a drive unit 150. The slide clutch mechanism 140 differs from the slide clutch mechanism 40 according to the embodiment in that it has a meshing part 170 instead of a meshing part 70. The slide clutch mechanism 140 is the same as the slide clutch mechanism 40 according to the embodiment in that it includes a drive wheel 41, a drive shaft 42, a clutch 60, and a holding part 43 (not shown). The meshing part 170 differs from the meshing part 70 in that it has a transfer pinion 171 instead of a lifting pinion 71, and does not have a lower counter wheel 72.

[0106] The transfer pinion 171 is driven by the drive motor of the drive wheel 41 and rotates in either forward or reverse direction. The transfer pinion 171 is movable in the axial direction relative to the drive shaft 42 via splines or the like. The transfer pinion 171 rotates with the drive motor of the drive wheel 41, but its axial position is controlled by another motor (not shown). The transfer pinion 171 is configured to mesh with a rack gear 126 provided on the conveyor station S.

[0107] The rack gear 126 is located below the conveyor station S. The rack gear 126 extends along the Z direction. The rack gear 126 includes a linear gear that meshes with the transfer pinion 171. The position of the rack gear 126 corresponds to the position of the advanced transfer pinion 171 in the width direction (Y direction) of the transport trolley 130.

[0108] When transferring cargo T from conveyor station S to transport trolley 130, the slide clutch mechanism 40 moves the drive shaft 42 from a first position P1 to a second position P2, causing the transfer pinion 171 to engage with the rack gear 126. At this time, the driving force of the drive unit 50 is transmitted to the conveyor station S via the drive shaft 42, the transfer pinion 171, and the rack gear 126. As a result, the conveyor station S can use the driving force of the drive unit 50 to transfer cargo T to the transport trolley 130 in a lifted state. Note that when transferring cargo T, the drive wheels 41 may be lifted off the horizontal rail 10 (not shown).

[0109] According to the slide clutch mechanism 140 of the third modified example, the load T can be transferred using the driving force of the transport trolley 130. This eliminates the need to install a drive device in the conveyor station S, allowing the conveyor station S to have a simpler configuration.

[0110] In the slide clutch mechanisms 40 and 140 according to the above embodiments and their respective modifications, the spline 42b formed on the side surface 42a of the drive shaft 42 was concave in the cross-section of the drive shaft 42 perpendicular to the axial direction D1, but is not limited to this. The second part 62 only needs to be rotatable together with the drive shaft 42. For example, the spline 42b formed on the side surface 42a of the drive shaft 42 may be convex in the cross-section of the drive shaft 42 perpendicular to the axial direction D1, and the inner surface 91c of the inner circumference portion 91a of the main body portion 91 of the second part 62 should be shaped to mesh with the spline 42b formed on the side surface 42a of the drive shaft 42. As an example, the spline 91d formed on the inner surface 91c of the inner circumference portion 91a of the main body portion 91 of the second part 62 may be concave in the cross-section of the main body portion 91 perpendicular to the axial direction D1.

[0111] The components in the above embodiments and modifications are not limited to the materials and shapes described above, and various materials and shapes can be applied to them. Each component in the above embodiments or modifications can be arbitrarily applied to each component in other embodiments or modifications. Parts of each component in the above embodiments or modifications can be omitted as appropriate without departing from the gist of one aspect of this disclosure.

[0112] 30, 130... Transport trolley, 40, 140... Slide clutch mechanism, 41... Drive wheel (base), 42... Drive shaft, 42a... Side (outer surface), 42c... End, 50, 150... Drive unit, 60... Clutch, 61... First part, 62... Second part, 63... Biasing part, 70, 170... Engagement part, 71... Lifting pinion (pinion gear), 26... Rack gear Ya (engaged portion), 81d, 181d, 281d...groove portion, 91...main body portion, 92, 192...projection portion, 192d...tapered portion, D1...axial direction, D2...radial direction, D3...circumferential direction, T1...first groove (tapered groove), T11...tapered surface (inner surface), T22, T122...side surface (inner surface), T103...third groove (tapered groove), T132...tapered surface (inner surface), Z...direction (extension direction)

Claims

1. A slide clutch mechanism comprising: a base; a shaft rotatably supported on the base; a meshing portion provided at one end of the shaft in the axial direction and configured to mesh with a mated portion; and a clutch provided between the base and the shaft, wherein the shaft is movable between a first position where the meshing portion is a predetermined distance away from the mated portion and a second position where the meshing portion meshes with the mated portion; and the clutch allows the base to rotate together with the shaft around the axis of the shaft when the shaft is in the first position, and allows the shaft to rotate relative to the base by a predetermined amount of rotational play around the axis when the shaft is in the second position.

2. The slide clutch mechanism according to claim 1, wherein the meshing portion includes a rack gear extending along an extending direction intersecting the axial direction, and the meshing portion includes a pinion gear configured to mesh with the rack gear.

3. The slide clutch mechanism according to claim 1, comprising: a first portion attached to the base; and a second portion attached to the shaft so as to be rotatable together with the shaft about an axis, wherein the second portion is rotatable together with the first portion about an axis when the shaft is in the first position; and is rotatable relative to the first portion about an amount of predetermined rotational play about an axis when the shaft is in the second position.

4. The slide clutch mechanism according to claim 3, wherein the first part has a groove formed therein that opens to one side in the axial direction, the second part has a main body attached to the shaft and a projection that protrudes from the main body radially in the direction of the shaft and is located in the groove, when the shaft is in the first position, a first play occurs between the projection and the inner surface of the groove when viewed in the axial direction, and when the shaft is in the second position, a second play occurs between the projection and the inner surface of the groove when viewed in the axial direction, and the first play is smaller than the second play.

5. The slide clutch mechanism according to claim 4, wherein the groove includes a tapered groove in the cross-section of the first portion perpendicular to the radial direction, the width along the circumferential direction of the shaft narrows as it approaches the other side in the axial direction, and the second play is the play between the inner surface of the tapered groove and the protrusion in the cross-section of the clutch perpendicular to the radial direction.

6. The slide clutch mechanism according to claim 4, wherein the protruding portion includes a tapered portion in the cross-section of the second portion perpendicular to the radial direction, the width along the circumferential direction of the shaft narrows as it approaches the other side in the axial direction, and the second play is the play between the tapered portion and the inner surface of the groove in the cross-section of the clutch perpendicular to the radial direction.

7. The slide clutch mechanism according to claim 6, wherein the groove portion includes a tapered groove in which the width along the circumferential direction of the shaft narrows as it approaches the other side in the axial direction in the cross section of the first portion perpendicular to the radial direction, and the first play is the play between the inner surface of the tapered groove and the tapered portion in the cross section of the clutch perpendicular to the radial direction.

8. The slide clutch mechanism according to claim 3, wherein the second part is spline-fitted to the outer circumferential surface of the shaft.

9. The slide clutch mechanism according to claim 3, wherein the clutch further comprises a biasing portion disposed between the first portion and the second portion, which biases the first portion and the second portion to move away from each other along the axial direction, and when the shaft is in the first position, the meshing portion presses the second portion in a direction against the biasing force of the biasing portion, so that the second portion becomes rotatable together with the first portion about the axis, and when the shaft is in the second position, the biasing portion biases the first portion and the second portion to move away from each other by a predetermined distance or more, so that the second portion becomes rotatable relative to the first portion about the axis by a predetermined amount of rotational play.

10. A transport trolley comprising: a slide clutch mechanism according to any one of claims 1 to 9; and a drive device for rotationally driving the shaft about the axis, wherein the base is a drive wheel, and when the shaft is in the first position, the drive wheel is rotationally driven to move along the horizontal direction, and when the shaft is in the second position, the meshing portion is rotationally driven by the drive device via the shaft to move along the extending direction of the meshed portion.

11. The transport trolley according to claim 10, wherein the drive wheels are rotationally driven by the drive device via the shaft and the clutch when the shaft is in the second position.

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