Wheel manufacturing device and wheel manufacturing method

Abstract

To provide a wheel manufacturing device which can easily manufacture a wheel having an annular core material and a plurality of free rollers rotatably supported by the core material, and a wheel manufacturing method.SOLUTION: A wheel manufacturing device 1 for manufacturing a wheel having a core body 2 constituted of a plurality of segments 7 and a plurality of free rollers 3 rotatably provided around an annular axial line of the core body, comprises a central jig 29 having a circular outer contour. and has a holding jig 21 and a laser welder 23 which welds adjacent ones of the segments. The laser welder sets a laser optical axis E to a direction orthogonal to an outer peripheral surface 7A of the segment when welding a portion distant from a central axis of the annular axial line out of outer peripheral surfaces of the segments, and sets the optical axis to a direction inclined on the side distant from the central axis with respect to a direction orthogonal to the outer peripheral surfaces of the segments when welding a portion close to the central axis out of the outer peripheral surfaces of the segments.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wheel manufacturing apparatus, a wheel manufacturing method, and a welding method for manufacturing wheels used in an omnidirectional mobile device. [Background technology]

[0002] Patent Document 1 discloses a method for manufacturing wheels used in omnidirectional mobile devices. The wheel has an annular core and multiple free rollers rotatably supported on the core. The method for manufacturing the wheel includes the following steps: a first step of forming multiple notches in a straight pipe; a second step of attaching multiple free rollers to the straight pipe; a third step of bending the pipe at multiple locations to fill the multiple notches and form a ring; and a fourth step of welding the ends of the pipe together and welding the edges of each notch together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6746655 specification Summary of the Invention [Problem to be solved by the invention]

[0004] In the fourth step, the ends of the pipes (also called segments) with the free rollers attached are welded together. However, because the free rollers are attached to the pipes, it is difficult to access the pipes, making TIG welding difficult. Therefore, there is a need for a wheel manufacturing device that can easily weld pipes and easily construct cores.

[0005] In view of the above background, the present invention aims to provide a wheel manufacturing apparatus and a wheel manufacturing method that can easily manufacture wheels having an annular core material and a plurality of free rollers rotatably supported on the core material. [Means for solving the problem]

[0006] In order to solve the above problem, one aspect of the present invention is a wheel manufacturing apparatus (1) for manufacturing a wheel having an annular core body (2) composed of a plurality of arc-shaped segments (7) connected to each other, and a plurality of free rollers (3) freely rotatable around the annular axis of the core body, the apparatus comprising: a central jig (29) having a circular outer contour; a holder (21) for holding the segments in a butted position on the outer periphery of the central jig; and a laser welding machine (23) for welding adjacent segments by irradiating them with a laser, wherein when welding a portion of the outer surface of the segment away from the central axis of the annular axis, the laser welding machine sets the optical axis (E) of the laser in a direction perpendicular to the outer surface (7A) of the segment, and when welding a portion of the outer surface of the segment close to the central axis, the optical axis is set in a direction inclined away from the central axis with respect to the direction perpendicular to the outer surface of the segment.

[0007] According to this aspect, even if free rollers are provided on the segments, the segments can be welded along their entire circumferential direction to form a core member while avoiding interference between the free rollers and the laser welder. Thus, a wheel manufacturing apparatus can be provided that can easily manufacture a wheel having an annular core member and a plurality of free rollers rotatably supported on the core member.

[0008] In the above aspect, preferably, the laser welding machine includes a head (71) that irradiates the laser and a manipulator (73) that moves the head, and when welding the segments, the manipulator positions at least a portion of the head in a position that overlaps with the free roller when viewed in the axial direction of the segments.

[0009] According to this aspect, the head can be brought closer to the segments, thereby more reliably welding adjacent segments.

[0010] In the above aspect, preferably, the holder holds the segment from both sides of the central axis.

[0011] According to this aspect, the segments can be held well by the holder.

[0012] In the above aspect, preferably, the holding device further includes a support member (27) that supports the central jig, and the central jig has a chuck (41), a plurality of bases (43) that are supported radially movably on the chuck and can abut against the free rollers by moving radially outward, and a shaft (45) provided at the center of the chuck, and the support member supports both ends of the shaft.

[0013] According to this aspect, the holder can have a simple structure, and the holder can support the segments well.

[0014] In the above aspect, the shaft is preferably located radially inside the base.

[0015] According to this aspect, the holder can be made compact, and interference between the shaft and the laser welder is reduced during welding.

[0016] In the above aspect, preferably, the shaft restricts radially inward movement of the base by abutting against the radially inner side of the base.

[0017] According to this aspect, the base can be held in an appropriate position relative to the chuck with a simple configuration.

[0018] In the above aspect, preferably, the chuck has a through hole (42) through which the shaft passes, and the shaft has a first member (65) inserted into the through hole from one side and a second member (67) connected to the first member on the other side of the through hole.

[0019] According to this aspect, the shaft can be simply configured and the shaft can be easily assembled.

[0020] In the above aspect, preferably, the first member and the second member are provided with a screw hole (69) that communicates with each other in the axial direction.

[0021] According to this embodiment, the first member and the second member can be firmly joined together.

[0022] In the above aspect, preferably, the support member has V-shaped grooves (39) that are recessed downward and receive the two end portions of the shaft, respectively.

[0023] According to this aspect, the segments can be held by the holding member so that they can rotate about the axis of the shaft, allowing the manufacturing worker to adjust the positions of the segments so that the points to be welded on the segments are in the appropriate positions.

[0024] In the above aspect, preferably, the width of the base in a direction parallel to the central axis is smaller than the width of the free roller in a direction parallel to the central axis.

[0025] According to this aspect, the axial width of the base is smaller than the axial width of the free roller, so that the base is less likely to interfere with the operation of the laser welder during welding.

[0026] In order to solve the above problem, one aspect of the present invention is a wheel manufacturing method for manufacturing a wheel having an annular core body (2) composed of a plurality of arc-shaped segments (7) connected to each other, and a plurality of free rollers (3) freely rotatable around the annular axis of the core body, the method comprising: a holding step of holding the segments in a butted state on the outer periphery of a central jig (29) having a circular outer contour; and a welding step of welding adjacent segments together by irradiating them with a laser, wherein when welding portions of the outer surfaces of the segments away from the central axis of the annular axis, the optical axis (E) of the laser is set in a direction perpendicular to the outer surface (7A) of the segment, and when welding portions of the outer surfaces of the segments close to the central axis, the optical axis is set in a direction inclined away from the central axis with respect to the direction perpendicular to the outer surface of the segment.

[0027] According to this aspect, the core member is formed by laser welding the segments. Therefore, even if the segments are provided with free rollers, the segments can be welded along their entire circumferential direction while avoiding interference between the free rollers and the laser welder. This provides a wheel manufacturing method that can easily manufacture a wheel having an annular core member and a plurality of free rollers rotatably supported on the core member. [Effects of the Invention]

[0028] According to the above configuration, it is possible to provide a wheel manufacturing apparatus and a wheel manufacturing method that can easily manufacture wheels having an annular core material and a plurality of free rollers rotatably supported on the core material. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a perspective view of a wheel manufacturing apparatus according to an embodiment, and an enlarged view of a portion surrounded by a dashed line; [Figure 2] Cross-section of an omnidirectional mobile device with wheels [Figure 3] Wheel side view [Figure 4]FIG. 1 is a perspective view showing a pipe member provided with free rollers; [Figure 5] Cross-sectional view of the wheel and its enlarged view [Figure 6] A perspective view showing the wheel being fixed to the holder and being welded. [Figure 7] FIG. 1 is an exploded perspective view of a holder according to an embodiment. [Figure 8] 1A is a cross-sectional view of a center jig showing a state where a locking member is inserted into a locking hole, and FIG. 1B is a cross-sectional view of a center jig showing a state where the locking member is removed from a locking hole. [Figure 9] (A) A cross-sectional view of a shaft according to an embodiment, and (B) a modified example thereof. [Figure 10] Laser welding machine block diagram [Figure 11] Schematic diagram showing setting input related to the laser irradiation direction [Figure 12] FIG. 10 is an explanatory diagram illustrating the movement of the head during laser irradiation. DETAILED DESCRIPTION OF THE INVENTION

[0030] A wheel manufacturing apparatus 1 according to the present invention will now be described with reference to the drawings. As shown in Fig. 1, the wheel manufacturing apparatus 1 is used to manufacture a wheel 4 having an annular core body 2 and a plurality of free rollers 3 rotatably mounted on the core body 2. As shown in Fig. 2, the wheel 4 manufactured by the wheel manufacturing apparatus 1 is mounted on an omnidirectional mobility device 5. The omnidirectional mobility device 5 is used in electric wheelchairs, carts, and personal mobility devices.

[0031] (Wheel 4 structure) As shown in FIG. 3, the core body 2 has an annular shape centered on the axis A. As shown in FIG. 4, the core body 2 is made up of a plurality of pipe materials 7 each having an arc shape and butt-welded to each other at its end. The pipe materials 7 correspond to the segments that make up the core body 2. That is, the core body 2 is made up of a plurality of segments (pipe materials 7) each having an arc shape and connected to each other. In this embodiment, the core body 2 is made up of two semicircular pipe materials 7 (segments) that are semicircular and connected to each other.

[0032] As shown in Fig. 4, the pipe material 7 is a so-called round pipe material having a cylindrical shape with a circular cross section, and is made of a metal such as stainless steel. As shown in Fig. 3, a line passing through the center of the cross section of the core body 2 (hereinafter referred to as annular axis B) extends in the circumferential direction centered on axis A, and forms an annular shape centered on axis A.

[0033] 5, each free roller 3 is supported by the core body 2 via a bearing 8, which is a radial bearing. The bearing 8 is preferably a ball bearing having an inner race 11, an outer race 12, a plurality of balls 13 interposed between the inner race 11 and the outer race 12, and a retainer (not shown) that holds the plurality of balls 13.

[0034] Each free roller 3 has a sleeve 15 and a rubber ring 16 provided on the outer peripheral surface of the sleeve 15. The sleeve 15 is preferably made of metal. The rubber ring 16 is preferably bonded to the outer peripheral surface of the sleeve 15 by vulcanization bonding or the like. A bearing 8 is disposed inside the sleeve 15. In this embodiment, two bearings 8 are disposed inside each sleeve 15 at a distance from each other, and the two bearings 8 are press-fitted into the inside of each sleeve 15.

[0035] The outer peripheral surface of the core body 2 is pressed against the inner peripheral surface of the inner race 11 of each bearing 8. As a result, the inner race 11 of each bearing 8 is fixed to the outer peripheral surface of the core body 2. In this embodiment, an annular collar 19 is provided on the outer peripheral surface of the core body 2. The outer peripheral surface of the core body 2 is pressed against the inner peripheral surface of the collar 19, thereby fixing the collar 19 to the core body 2. The collar 19 locks the edge of the inner race 11 and restricts movement of each inner race 11 relative to the core body 2 in the circumferential direction around the axis A.

[0036] Each of the free rollers 3 rotates relative to the core body 2 about an annular axis B. Also, each of the free rollers 3 rotates relative to the core body 2 about an axis parallel to a tangent to the axis A.

[0037] (Wheel manufacturing method) Next, an outline of a method for manufacturing the wheel 4 will be described.

[0038] In the first step (first step) of the manufacturing process for the wheel 4, a worker who manufactures the wheel 4 prepares a pipe material 7 that has been bent into a semicircular shape in advance. Next, the worker arranges a plurality of free rollers 3, each with a pair of bearings 8 and a collar 19 attached, in appropriate positions on the pipe material 7. After that, the worker introduces a liquid, gas, or the like into the inside of the pipe material 7 to apply pressure, thereby expanding the diameter of the pipe material 7 and fixing the inner race 11 of the bearing 8 to the pipe material 7. As a result, the free rollers 3 are each rotatably coupled to the pipe material 7.

[0039] The worker performs the first step at least twice to prepare at least two pipe materials 7 (see FIG. 4) to which free rollers 3 are attached. The worker then butts the ends of the pipe materials 7 together to form a ring, and then performs the second step of assembling them into the wheel manufacturing apparatus 1 (see FIG. 1) and welding the ends of two adjacent pipe materials 7. This joins the two adjacent pipe materials 7 to form an annular core body 2, completing the main wheel. The wheel manufacturing apparatus 1 according to this embodiment is particularly suitable for holding and welding the pipe materials 7 in the second step.

[0040] (Wheel manufacturing equipment) Next, the configuration of the wheel manufacturing apparatus 1 will be described.

[0041] 1, the wheel manufacturing apparatus 1 includes a holder 21 and a laser welder 23. In this embodiment, the wheel manufacturing apparatus 1 is placed on a workbench 25 for manufacturing wheels 4.

[0042] The holding fixture 21 (also called a wheel holding device) holds the arc-shaped pipe materials 7 provided with the free rollers 3 in a butted state during welding. As shown in Fig. 6, the holding fixture 21 includes a support member 27 (also called a base) and a center jig 29 (also called a center member) having a circular outer contour.

[0043] The support member 27 includes a pair of legs 31 and a base 33 supported by the pair of legs 31. Each leg 31 is made up of an L-shaped metal fitting. It is fixed to the upper surface of the workbench 25 on which the wheel manufacturing apparatus 1 is placed.

[0044] The base 33 is made of a metal plate material in a substantially U-shape. The base 33 is disposed so as to open upward, and is supported via the legs 31.

[0045] In detail, the base 33 includes a pair of flat plate portions 35 extending in the vertical direction and arranged parallel to each other, and a horizontal portion 37 connecting the lower ends of the flat plate portions 35. The upper ends of the legs 31 are fixed to the corresponding flat plate portions 35. A V-shaped groove 39 recessed downward is provided at the upper end of each of the flat plate portions 35.

[0046] The central jig 29 has a chuck 41, a plurality of bases 43 that are supported by the chuck 41 so as to be radially movable and that form the outer periphery of the central jig 29, and a shaft 45 that is provided at the center of the chuck 41.

[0047] 7, the chuck 41 is formed in a disk shape centered on a central axis C. The chuck 41 is preferably made of a metal such as stainless steel. A chuck through-hole 42 that penetrates the chuck 41 along the central axis C is provided in the center of the chuck 41.

[0048] Each of the bases 43 has a peripheral wall portion 46 that faces the outer peripheral surface of the chuck 41 and extends in an arc shape in the circumferential direction, and a pair of side walls 47 that extend from the peripheral wall portion 46 along the side surface of the chuck 41 toward the central axis C. Each of the pair of side walls 47 is preferably formed in a fan shape. The base 43 may be made of resin or the like, or may be made of a metal such as stainless steel.

[0049] The outer periphery of the peripheral wall 46 forms the outer periphery of the central jig 29. When the pipe 7 is attached to the holder 21, the free rollers 3 abut against the outer periphery of the peripheral wall 46, holding the pipe 7 in a butted state while maintaining the pipe 7 in a proper annular shape. To facilitate maintaining the free rollers 3 in a proper position, the outer periphery of the peripheral wall 46 may be provided with an engagement groove 49 (see also FIG. 12) that receives at least a portion of the free roller 3. The bases 43 may be formed to have the same shape as each other.

[0050] The width of the base 43 in a direction parallel to the central axis C is smaller than the width of the free rollers 3 in a direction parallel to the axis A.

[0051] As shown in FIGS. 6 and 7 , a guide groove 51 is formed in the side wall 47 of each base 43, penetrating the side wall 47 in the thickness direction. The guide groove 51 has an elongated hole shape extending radially outward. At least one guide pin 52 passing through the guide groove 51 is coupled to the chuck 41. The guide pin 52 abuts against the guide groove 51, thereby restricting the movement direction of the base 43 relative to the chuck 41 to be radially inward and outward. In this embodiment, two guide pins 52 are provided for one guide groove 51. By providing two or more guide pins 52 in the guide groove 51 in this way, the guide pins 52 abut against the guide groove 51, and the inclination angle of the base 43 relative to the chuck 41 is maintained constant.

[0052] In this way, the movement of each base 43 relative to the chuck 41 is restricted inward and outward radial directions by the contact between the guide groove 51 and the guide pin 52. Hereinafter, the position of the base 43 when the distance between the base 43 and the central axis C is minimum will be referred to as a contracted position, and the position of the base 43 when the distance between the base 43 and the central axis C is maximum will be referred to as an extended position.

[0053] As shown in Fig. 7, each base 43 and chuck 41 are connected by one or more spring ejector pins 55. As shown in Fig. 8, the spring ejector pin 55 includes a cylindrical tubular body 55A, a pin 55B received in the tubular body 55A so as to be slidable within a predetermined range along the axis of the tubular body 55A, and a spring 55C provided on the outer periphery of the pin 55B.

[0054] A male thread is provided on the outer peripheral surface of the cylindrical main body 55A. A screw hole 57 extending radially inward is provided on the outer peripheral surface of the chuck 41. The screw hole 57 preferably reaches the chuck through-hole 42. The cylindrical main body 55A is inserted into the screw hole 57, and the cylindrical main body 55A is screwed to the chuck 41.

[0055] The pin 55B has a shaft portion 58 received in the cylindrical main body 55A and two head portions 59 provided on both ends of the shaft portion 58. Both of the two head portions 59 have an outer diameter wider than the inner diameter of the cylindrical main body 55A, but the other head portion 59 is configured to have a wider outer diameter than the one head portion. The head portion 59 on one side is housed in the chuck through-hole 42. The head portion 59 on one side has an outer diameter smaller than the outer diameter of the cylindrical main body 55A but larger than the inner diameter of the cylindrical main body 55A. This restricts the head portion 59 on one side from moving radially outward.

[0056] A base through-hole 60 having a smaller diameter than the head 59 on the other side is provided in the outer wall of the base 43. The shaft 58 passes through the through-hole, and the head 59 on the other side is located radially outward of the outer wall of the base 43. The head 59 on the other side is formed wider than the base through-hole 60. This limits radially outward movement of the base 43 relative to the chuck 41.

[0057] The spring 55C is provided on the outer periphery of the pin 55B between the tubular main body 55A and the base 43, and biases the tubular main body 55A radially outward relative to the base 43. As a result, the spring 55C biases the corresponding base 43 toward the expanded position.

[0058] As shown in FIGS. 6 and 7, the center jig 29 is detachably attached to the chuck 41 and has multiple locking members 61 that abut against the bases 43 to restrict movement of the bases 43 relative to the chuck 41. As shown in FIGS. 7, 8A, and 8B, a locking hole 62, which is a through hole, is formed in the side wall of each base 43 and in the chuck 41. When the base 43 is pressed radially inward against the chuck 41, the locking hole 62 in the side wall of the base 43 and the locking hole 62 in the chuck 41 overlap each other (see FIG. 8A). On the other hand, when the locking member 61 is removed from the locking hole 62, the base 43 moves radially outward due to the biasing force of the spring 55C (see FIG. 8B). When the locking member 61 is inserted into each locking hole 62, movement of the base 43 relative to the chuck 41 is prohibited, and the base 43 is positioned appropriately. The locking member 61 may be, for example, a pin.

[0059] As shown in Fig. 6, the shaft 45 is provided at the center of the chuck 41 and is made of a cylindrical metal member having a central axis C. In this embodiment, the shaft 45 is fitted into the chuck through-hole 42 (see Fig. 7) and fixed to the chuck 41. The shaft 45 is inserted into the grooves 39 from above at both ends and received in the grooves 39.

[0060] Both ends of the shaft 45 are received in the grooves, so that the pipe 7 is held from both sides of the central axis C (both outer sides of the side walls 47 of the base 43). This allows the pipe 7 to be held well and stably with a simple configuration.

[0061] Furthermore, the shaft 45 is received in the groove portion 39, thereby supporting the center jig 29. Therefore, the pipe material 7 can be held by the support member 27 so that it can rotate around the central axis C. This allows the worker performing the manufacturing to easily adjust the position of the pipe material 7 so that the portion to be welded on the pipe material 7 is in an appropriate position where it can be welded by the laser welder 23.

[0062] In this embodiment, as shown in FIG. 7, the shaft 45 includes a first member 65 that is inserted into the chuck through-hole 42 from one side, and a second member 67 that is connected to the first member 65 on the other side of the chuck through-hole 42.

[0063] 9(A) and 9(B), the first member 65 includes a cylindrical first member head 65A and a first member shaft 65B that is narrower in the radial direction than the first member head 65A and protrudes from the first member head 65A along the central axis of the first member head 65A. The first member head 65A has a wider radial width than the inner diameter of the chuck through-hole 42.

[0064] The second member 67 includes a cylindrical second member head 67A and a second member shaft 67B that is narrower in the radial direction than the second member head 67A and protrudes from the second member head 67A along the central axis of the second member head 67A. The second member shaft 67B has a second member recess 67C at its tip that is recessed in the opposite direction to the protruding direction and can receive the tip of the first member shaft 65B. The second member head 67A has a radial width wider than the inner diameter of the chuck through-hole 42.

[0065] The second member 67 can be coupled to the first member 65 by inserting the first member 65 into the chuck through-hole 42 from one side, placing the second member 67 on the other side of the chuck through-hole 42, and inserting the tip of the first member shank 65B into the second member recess 67C. This allows the worker to easily assemble the shaft 45. Furthermore, because the shaft 45 is made up of two members, its configuration is simple.

[0066] 9(A), in this embodiment, a screw hole 69 that communicates with the first member 65 and the second member 67 in the central axis direction is provided in each of the first member 65 and the second member 67. By inserting a screw 70 into the screw hole 69, the first member 65 and the second member 67 can be firmly joined together.

[0067] However, the manner in which the first member 65 and the second member 67 are joined together is not limited to this. For example, as shown in Fig. 9(B), a male thread may be provided on the outer peripheral surface of the first member shaft portion 65B, a female thread that screws onto the male thread may be provided in the second member recessed portion 67C, and the first member 65 and the second member 67 may be joined together by screwing the first member shaft portion 65B into the second member recessed portion 67C.

[0068] When the base 43 is in a proper position relative to the chuck 41, the first member head 65A and / or the second member head 67A of the shaft 45 may be configured to abut against the radially inner side of the base 43, thereby restricting radially inward movement of the base 43. This allows the base 43 to be held in a proper position relative to the chuck 41 with a simple configuration.

[0069] The holder 21 may also include a clamp device that clamps the plurality of free rollers 3 in the circumferential direction of the wheel 4, a band member, etc. However, the clamp device and the band member are not essential and may be provided on the holder 21 as needed.

[0070] The laser welding machine 23 irradiates a laser to weld adjacent pieces of the pipe material 7 held by the holder 21 together. The adjacent pieces of the pipe material 7 are welded together (butt welded) to form the core body 2. The laser welding machine 23 may be a device that performs welding using any laser, such as a YAG laser, a CO2 laser, a fiber laser, or a disk laser.

[0071] As shown in FIG. 1, the laser welding machine 23 includes a head 71 that irradiates the pipe material 7 with a laser, a manipulator 73 that moves the head 71, and a controller 75 that drives and controls the manipulator 73.

[0072] The head 71 has a generally columnar shape extending in a predetermined direction around an axis. The head 71 irradiates a laser beam from an end face on one end side in the extension direction (hereinafter referred to as the irradiation end 71A) along an optical axis E extending in the extension direction. The end of the head 71 on the irradiation end 71A side may be configured to be large enough to be inserted between adjacent free rollers 3.

[0073] The manipulator 73 is fixed at its base end to the workbench 25 and is configured as an articulated robot arm with a head 71 at its tip. By driving the joints, the manipulator 73 can move the head 71 along a trajectory instructed by the controller 75 and in a posture instructed by the controller 75. In Figures 1 and 6, examples of the position of the head 71 are also shown by dashed lines and two-dot dashed lines.

[0074] 10, the controller 75 is configured by a computer including a processor 77 configured by a CPU (Central Processing Unit) etc., a memory 78 configured by a RAM (Random Access Memory), a ROM (Read Only Memory) etc., and a storage device 79 configured by an SSD (Solid State Drive), an HDD (Hard Disk Drive) etc. The controller 75 also includes a touch panel 81. The touch panel 81 functions as an input / output device that receives input from an operator and displays information to the operator.

[0075] The controller 75 receives information from the worker on the touch panel 81 regarding the movement trajectory D of the head 71 and the direction of the optical axis E at each position on the trajectory (see, for example, FIG. 11). When the controller 75 receives an input regarding the start of work on the touch panel 81, it drives the manipulator 73 so that the head 71 moves along the movement trajectory D and the optical axis E is oriented in the input direction, and performs welding processing by irradiating a laser from the head 71.

[0076] Next, the second step of holding and welding the pipe material 7 will be described in detail.

[0077] The worker butts together both ends of the two pipe materials 7 after the free rollers 3 have been attached (i.e., the first step is complete), and temporarily fastens them together to form the wheel 4 before actual welding. Thereafter, the worker performs a holding step in which the pipe materials 7 are held in a butted (i.e., temporarily fastened) state on the outer periphery of a central jig 29 having a circular outer contour by setting them in a holding fixture 21.

[0078] In the holding process, the worker first removes the locking members 61 inserted into the locking holes 62 of the center jig 29, and expands the diameter of the bases 43 relative to the chuck 41. Then, while reducing the diameter of the bases 43, the worker inserts them into the inside of the wheel 4 before main welding, and inserts the locking members 61 into the locking holes 62. This maintains each base 43 in an appropriate position relative to the chuck 41.

[0079] Thereafter, the worker attaches the first member 65 and the second member 67 that constitute the shaft 45. As a result, the radially inner end of the base 43 abuts against the first member 65 or the second member 67 that constitutes the shaft 45, and radially inward movement of the base 43 is restricted.

[0080] The worker inserts both ends of the shaft 45 into the grooves 39 provided at the upper end of the base 33. As a result, the wheel 4 before main welding is supported by the holder 21 so as to be rotatable about an axis extending horizontally, completing the holding process. At this time, the free rollers 3 are inserted into the engagement grooves 49.

[0081] Next, the worker performs a welding process in which adjacent pieces of pipe material 7 are welded together by irradiating them with a laser. In the welding process, the worker first performs setting input on the touch panel 81 of the controller 75 regarding the movement trajectory D of the head 71 and the direction of the optical axis E at each position, which are schematically shown in Fig. 11. In Fig. 11, the movement trajectory D of the head 71 is schematically shown by a thick arrow, the attitude of the head 71 at each position is shown by a triangle, and the optical axis E at each point is shown by a dashed line.

[0082] 11, the movement trajectory D of the head 71 includes a first region X, a second region Y, and a third region Z. In the first region X, the head 71 slides upward (away from the central axis C) from a position where the optical axis E extending from the irradiation end 71A is at the lower end of the pipe 7 (the end on the side closer to the central axis C). In the second region Y, the head 71 rotates around the annular axis B of the pipe 7. In the third region Z, the head 71 slides downward until the optical axis E extending from the irradiation end 71A reaches the lower end of the pipe 7.

[0083] As shown in FIG. 12, in the first region X and the second region Y, the head 71 may be positioned so that at least a portion thereof overlaps with the free roller 3 when viewed in the axial direction of the pipe material 7. This allows the head 71 and the pipe material 7 to be closer to each other. This allows the pipe material 7 to be welded more reliably. Furthermore, the wheel manufacturing apparatus 1 can be configured compactly.

[0084] 11, in the first region X and the third region Z, the worker sets the optical axis E to point below the lower half of the pipe 7, i.e., toward a portion closer to the central axis C of the pipe 7. Also, in the first region X and the third region Z, the worker sets the optical axis E in a direction inclined away from the central axis C from a direction perpendicular to the outer circumferential surface 7A of the pipe 7 (segment), i.e., toward a direction more horizontal.

[0085] On the other hand, in the second region Y, the worker sets the optical axis E to point toward an upper portion of the pipe 7, i.e., a portion farther away from the central axis C of the pipe 7, than in the first region X and the third region Z. Also, in the second region Y, the worker sets the optical axis E in a direction perpendicular to the outer peripheral surface 7A of the pipe 7 (segment).

[0086] Once the setting input is complete, the worker adjusts the posture of the wheel 4 before the actual welding so that one of the pre-welded portions of the two pipe materials 7 is at the upper end, and then inputs information related to the start of work on the touch panel 81. When the input related to the start of work is input to the touch panel 81, the controller 75 (more specifically, the processor 77) executes the welding process. In the welding process, the processor 77 controls the drive of the manipulator 73 and the head 71 so that the head 71 moves in accordance with the setting input and the laser is irradiated onto one of the pre-welded portions. As a result, one of the pre-welded portions is welded, and the ends of the adjacent pipe materials 7 (segments) that make up one of the pre-welded portions are actually welded together.

[0087] Next, the worker rotates the wheel 4 before the actual welding so that the other of the pre-welded portions of the two pipe materials 7 is at the upper end, adjusts the position of the pipe materials 7, and then inputs information related to the start of work on the touch panel 81. When information related to the start of work is input to the touch panel 81, the controller 75 (more specifically, the processor 77) executes the welding process. In the welding process, the processor 77 controls the drive of the manipulator 73 and the head 71 so that the head 71 moves in accordance with the setting input and the laser is irradiated onto the other of the pre-welded portions. As a result, the other of the pre-welded portions is welded, and the ends of the adjacent pipe materials 7 (segments) that make up the other of the pre-welded portions are actually welded together.

[0088] After the main welding is completed, the worker removes the shaft 45 from the chuck 41. This allows the bases 43 to move toward the central axis C. Then, by moving the multiple bases 43 toward the central axis C against the biasing force of the springs 55C, the inner peripheral portion of the wheel 4 and the outer peripheral portions of the multiple bases 43 are separated, and the wheel 4 is removed from the center jig 29.

[0089] Next, the effects of the wheel manufacturing apparatus 1 configured as above and the method for manufacturing the wheel 4 will be described.

[0090] Of the pre-welded portions of the pipe material 7, the portions away from the axis A (central axis C) of the annular axis B can be accessed from the radially outside of the core body 2, making welding relatively easy. On the other hand, the portions close to the axis A (central axis C) of the annular axis B must be accessed from the radially inside of the core body 2, making welding less easy.

[0091] The wheel manufacturing apparatus 1 is equipped with a laser welder 23 that can perform welding from a position farther away than TIG welding. When the head 71 is positioned in the second region Y, a portion of the pipe material 7 that is far from the central axis C is welded, and at this time, the optical axis E of the laser is set in a direction perpendicular to the outer peripheral surface 7A of the pipe material 7. On the other hand, when the head 71 is positioned in the first region X or the third region Z, a portion of the pipe material 7 that is close to the central axis C is welded, and at this time, the laser is set to be directed in a direction inclined from the direction perpendicular to the outer peripheral surface 7A of the pipe material 7 (non-perpendicular direction). In particular, the optical axis E of the laser is set in a direction inclined away from the central axis C, i.e., toward the horizontal direction.

[0092] 12, the pipe material 7 can be welded while avoiding interference between the free rollers 3 and the laser welding machine 23 and between the laser welding machine 23 and the holder 21 in the portion close to the central axis C of the pipe material 7. Therefore, the wheel manufacturing apparatus 1 and the method for manufacturing a wheel 4 according to the present invention can provide the wheel manufacturing apparatus 1 and the method for manufacturing a wheel 4 that can easily manufacture a wheel 4 having an annular pipe material 7 and a plurality of free rollers 3 rotatably supported on the pipe material 7.

[0093] When the wheel 4 is held by the holder 21, the free rollers 3 are received in the engagement grooves 49. As shown in Fig. 12, the width of the base 43 in a direction parallel to the central axis C is smaller than the width of the free rollers 3 in a direction parallel to the central axis C (axis A). This allows the wheel manufacturing apparatus 1 to be more compact than when the width of the base 43 in a direction parallel to the central axis C is larger than the width of the free rollers 3 in a direction parallel to the central axis C. Furthermore, by reducing the width of the base 43 in a direction parallel to the central axis C, the movement of the head 71 of the laser welder 23 is less likely to be hindered by the base 43 when welding a portion of the annular axis B close to the axis A (central axis C), making it easier to perform welding work on the pipe material 7 (core body 2) from the radially inner side.

[0094] Furthermore, shaft 45 is located radially inward of base 43. This allows holder 21 to be configured compactly, making it less likely that shaft 45 will interfere with head 71 during welding, and making it less likely that shaft 45 will interfere with the movement of head 71 of laser welder 23.

[0095] The shaft 45 is received at both ends in the grooves 39, so that the center jig 29 is rotatably supported on the base 33. By rotating the center jig 29, the worker performing the manufacturing can easily adjust the position of the pipe material 7 to be welded.

[0096] Next, an example of how the wheel 4 manufactured in this manner can be used will be described. The wheel 4 is primarily used in an omnidirectional vehicle 5. As shown in FIG. 2 , the omnidirectional vehicle 5 includes a frame 91, a pair of drive discs 92 rotatably supported on the frame 91, an annular wheel 4 disposed between the pair of drive discs 92, and a pair of electric motors that rotate the drive discs 92. The pair of drive discs 92 transmit the driving force of the electric motor to the wheels 4.

[0097] The frame 91 has a pair of side walls extending downward from the lower part of the vehicle body. As shown in FIG. 2, a support shaft 97 extending in the left-right direction is suspended between the lower ends of the pair of frames 91. A pair of drive disks 92 are rotatably supported on the support shaft 97. The pair of drive disks 92 rotate around the axis of the support shaft 97. The position of each drive disk 92 in the left-right direction is restricted relative to the support shaft 97. The drive disks 92 face each other at a distance in the left-right direction.

[0098] The drive discs 92 are arranged on both sides of the annular wheel 4 and apply frictional force to the wheel 4 to rotate the wheel 4 about axis A and annular axis B. The drive disc 92 has a disk-shaped base 101 rotatably supported by the frame 91, and a plurality of drive rollers 102 rotatably supported on the outer periphery of the base 101 at an angle to each other and in contact with the wheel 4. The base 101 is arranged coaxially with the support shaft 97.

[0099] A driven pulley 104 is provided on each of the opposing surfaces of each drive disc 92. The driven pulley 104 is provided coaxially with the drive disc 92. The driven pulley 104 is connected by a belt 106 to a drive pulley provided on the output shaft of the electric motor. As each electric motor rotates independently of each other, each drive disc 92 rotates independently of each other.

[0100] In each omnidirectional vehicle 5, when a pair of drive discs 92 rotate in the same direction at the same rotational speed, the wheels 4 rotate together with the pair of drive discs 92. That is, the wheels 4 rotate forward or backward about axis A. At this time, the drive rollers 102 of the drive discs 92 and the free rollers 3 of the wheels 4 do not rotate relative to the core body 2. In each omnidirectional vehicle 5, when a difference in rotational speed occurs between the pair of drive discs 92, a component force perpendicular to the circumferential (tangential) force caused by the rotation of the pair of drive discs 92 acts from the left and right drive rollers 102 on the free rollers 3 of the wheels 4. Because the axes of the drive rollers 102 are inclined with respect to the circumferential direction of the drive rollers 102, a component force is generated between the drive discs 92 due to the difference in rotational speed. This component force causes the drive rollers 102 to rotate relative to the base 101, and the free rollers 3 to rotate relative to the core body 2. As a result, the wheels 4 generate a driving force in the left and right directions.

[0101] The left and right omnidirectional mobile devices 5 rotate forward at the same speed, causing the vehicle body to move forward. The left and right omnidirectional mobile devices 5 rotate backward at the same speed, causing the vehicle body to move backward. The left and right omnidirectional mobile devices 5 generate speed as they rotate forward and backward, causing the vehicle body to turn right or left. The free rollers 3 of each wheel 4 of the left and right omnidirectional mobile devices 5 rotate, causing the vehicle body to move parallel to the right or left.

[0102] Although the specific embodiment has been described above, the present invention is not limited to the above embodiment and can be widely modified. The support member 27 may have a mechanism for changing the height and orientation of the center jig 29. The shape and number of the bases 43 can be changed as desired.

[0103] The movement trajectory D may include a first region X, a second region Y, and a third region Z. For example, between the first region X and the second region Y, there may be provided a region in which the optical axis E is changed to be perpendicular to the outer circumferential surface 7A while the head 71 is raised. Furthermore, between the second region Y and the third region Z, there may be provided a region in which the optical axis E is changed little by little to be horizontal while the head 71 is lowered. [Explanation of symbols]

[0104] 1:Wheel manufacturing equipment 2: Core body 3: Free roller 4: Wheels 7: Pipe material (segment) 21: Holder 23: Laser welding machine 27: Support member 29: Center jig 39: Groove (groove) 41: Zipper 42: Chuck through hole (through hole) 43: Bass 45: Shaft 65: First member 67: Second member 69: Threaded hole 70: Screw 71: Head 73: Manipulator B: Circular axis C: Central axis line (center axis)

Claims

1. 1. A wheel manufacturing apparatus for manufacturing a wheel having an annular core body formed by a plurality of arc-shaped segments connected to each other, and a plurality of free rollers provided rotatably around an annular axis of the core body, a holder having a central jig having a circular outer contour, the holder holding the segments in abutting relationship to the outer periphery of the central jig; a laser welder that welds adjacent ones of the segments together by irradiating them with a laser, When welding a portion of the outer surface of the segment away from the central axis of the annular axis, the laser welding machine sets the optical axis of the laser in a direction perpendicular to the outer surface of the segment, and when welding a portion of the outer surface of the segment close to the central axis, the laser welding machine sets the optical axis in a direction inclined away from the central axis with respect to the direction perpendicular to the outer surface of the segment.

2. the laser welding machine includes a head that irradiates the laser and a manipulator that moves the head; The wheel manufacturing apparatus according to claim 1 , wherein the manipulator positions at least a portion of the head at a position overlapping with the free roller when viewed in the axial direction of the segment when welding the segment.

3. The wheel manufacturing apparatus according to claim 1 , wherein the holding fixture holds the segment from both sides of the central shaft.

4. The holding tool further includes a support member that supports the center jig, the central jig includes a chuck, a plurality of bases that are supported by the chuck so as to be movable in a radial direction and that can move radially outward to come into contact with the free rollers, and a shaft that is provided at the center of the chuck, 2. The wheel manufacturing apparatus according to claim 1, wherein the support members support both ends of the shaft.

5. The wheel manufacturing apparatus according to claim 4, wherein the shaft is located radially inward of the base.

6. The wheel manufacturing apparatus according to claim 5 , wherein the shaft restricts radially inward movement of the base by abutting against a radially inner side of the base.

7. the chuck has a through hole through which the shaft passes; 7. A wheel manufacturing apparatus according to claim 4, wherein the shaft comprises a first member inserted into the through hole from one side, and a second member coupled to the first member on the other side of the through hole.

8. 8. The wheel manufacturing apparatus according to claim 7, wherein the first member and the second member are provided with threaded holes communicating in the axial direction.

9. 5. A wheel manufacturing apparatus according to claim 4, wherein the support member has a V-shaped groove recessed downward and adapted to receive the opposite ends of the shaft.

10. 5. The wheel manufacturing apparatus according to claim 4, wherein a width of the base in a direction parallel to the central axis is smaller than a width of the free roller in a direction parallel to the central axis.

11. A method for manufacturing a wheel having an annular core body formed by a plurality of arc-shaped segments connected to each other, and a plurality of free rollers provided rotatably around an annular axis of the core body, comprising: a holding step of holding the segments in abutting relationship to each other on the outer periphery of a central jig having a circular outer contour; a welding step of welding adjacent ones of the segments together by irradiating them with a laser, A method for manufacturing a wheel, wherein when welding a portion of the outer surface of the segment away from the central axis of the annular axis, the optical axis of the laser is set in a direction perpendicular to the outer surface of the segment, and when welding a portion of the outer surface of the segment close to the central axis, the optical axis is set in a direction inclined away from the central axis with respect to the direction perpendicular to the outer surface of the segment.

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