A Mecanum omnidirectional wheel and assembly method

Abstract

The present invention discloses a Mecanum omnidirectional wheel and an assembly method, comprising a wheel hub, two baffles and a plurality of roller bodies, wherein the two baffles are respectively fixed to the two end surfaces of the wheel hub; the roller body is arranged around the axial direction of the wheel hub, and the axis of the roller body is 45° with the axis of the roller body; the roller body is rotatably connected to the two baffles through a connecting shaft, and fasteners are detachably arranged at both ends of the connecting shaft, and the fasteners can fix the connecting shaft to the two baffles. The present invention is convenient for replacing the roller body, and at the same time, a compensation value is set according to the force overlap area of ​​the roller body, so that the envelope line is located within the range of the adjacent envelope surface, so that the Mecanum omnidirectional wheel avoids the narrow side of the roller body from bearing the load during the actual operation process, and avoids excessive radial deformation of the narrow side rubber layer during use, resulting in stress concentration at the narrow side rubber layer position, and excessive temperature rise leading to rubber layer shedding.

Description

Technical Field

[0001] The invention relates to the field of wheel set accessories, and in particular to a Mecanum omnidirectional wheel and an assembly method. Background Art

[0002] Mecanum wheels are different from traditional wheels. They are assembled from several rollers according to certain requirements. Usually, the design axis of the wheel hub and the design axis of the roller are 45 degrees. By combining multiple Mecanum wheels, the vehicle body can move and rotate in any direction in the plane. Usually, a complete Mecanum wheel motion system uses multiple motors to synchronously drive and precisely regulate the speed to achieve omnidirectional movement of the vehicle body.

[0003] In the process of replacing the roller in the prior art, the shaft inserted in the roller needs to be pulled out first before the roller and the hub can be separated. Because there is a certain damping force when the shaft is pulled out from the roller, it is difficult to separate the roller and the hub, so the above separation method is not convenient for roller replacement. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a Mecanum omnidirectional wheel and an assembly method, which are convenient for replacing a roller body.

[0005] In order to solve the above technical problems, the present invention provides a Mecanum omnidirectional wheel, comprising a hub, two baffles and a plurality of roller bodies, wherein the two baffles are respectively fixed to the two end surfaces of the hub; the roller body is arranged around the axial direction of the hub, and the axis of the roller body is 45° with the axis of the roller body; the roller body is rotatably connected to the two baffles through a connecting shaft, and fasteners are detachably provided at both ends of the connecting shaft, and the fasteners can fix the connecting shaft and the two baffles.

[0006] Furthermore, combined bearings are embedded at both ends of the roller body, and the end faces of the combined bearings protrude from the end faces of the roller body.

[0007] Furthermore, abutment members are provided on both sides of the roller body, and two ends of the abutment members are respectively fitted with the combined bearing and the blocking sheet to fill the installation gap.

[0008] Furthermore, the abutment member is a spring washer or a wave spring.

[0009] Furthermore, thread glue is coated on the connection between the connecting shaft and the fastener.

[0010] Furthermore, a plurality of threaded holes are provided on the two baffles, and the hub can be key-connected or flange-connected to the driving member.

[0011] Furthermore, a plurality of positioning holes are provided on the wheel hub and the two baffles.

[0012] Furthermore, the outside of the roller body is coated with a protective layer.

[0013] Another object of the present invention is to provide an assembly method for a Mecanum omnidirectional wheel, comprising the following steps:

[0014] S1. Establish a reference system including a "top" reference surface, a "middle" reference surface, and a "bottom" reference surface according to the width direction of the Mecanum omnidirectional wheel;

[0015] S2. Establishing a reference axis in the “middle” reference plane, wherein the reference axis is 45° to the “middle” reference plane;

[0016] S3, establishing a "side" reference surface passing through the reference axis, used as a rotation reference surface;

[0017] S4, drawing the envelope of the Mecanum omnidirectional wheel on the “top” reference surface, the “middle” reference surface, and the “bottom” reference surface;

[0018] S5, drawing the envelope surface of the roller body on the “side” reference surface to rotate and form the roller body;

[0019] S6, arranging all the rollers and determining the force-bearing overlap areas of the rollers;

[0020] S7. Set a compensation value according to the force overlap area of ​​the roller body, wherein the compensation value is the distance from the maximum outer diameter of the roller body in the direction away from the reference system, so that the envelope line is located within the range of the adjacent envelope surface.

[0021] Further, in step S7, the compensation value is 0.5 mm-3 mm.

[0022] Beneficial effects of the present invention:

[0023] When removing the roller body, first separate the two fasteners from the connecting shaft, then the roller body and the connecting shaft located between the two baffles can be directly separated from the baffles, so that the roller body and the wheel hub can be separated without separating the connecting shaft and the roller body, thereby facilitating the replacement of the roller body;

[0024] The compensation value is set according to the force overlap area of ​​the roller body so that the envelope line is within the range of the adjacent envelope surface, so that the Mecanum omnidirectional wheel avoids the narrow side of the roller body to bear the load during actual operation, avoiding excessive radial deformation of the narrow side rubber layer during use, resulting in stress concentration at the narrow side rubber layer position, and excessive temperature rise leading to rubber layer shedding. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an overall schematic diagram of the present invention;

[0026] Figure 2 It is a schematic diagram of the arrangement of the roller body in the present invention;

[0027] Figure 3 Schematic diagram of the arrangement and deployment of the roller bodies in the present invention;

[0028] Figure 4 It is a structural schematic diagram of the roller body in the present invention;

[0029] Figure 5 is a cross-sectional view of a roller body in the present invention;

[0030] Figure 6 It is a schematic structural diagram of the wheel hub and the baffle in the present invention.

[0031] Explanation of the numbers in the figure: 1. wheel hub; 2. baffle; 21. threaded hole; 22. mounting groove; 23. positioning hole; 3. roller body; 31. combined bearing; 32. abutment member; 33. protective layer; 4. connecting shaft; 41. fastener. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0033] Reference Figure 1 As shown, an embodiment of a Mecanum omnidirectional wheel and an assembly method of the present invention comprises a wheel hub 1, two baffles 2 and a plurality of roller bodies 3. The two baffles 2 are fixed to the two end surfaces of the wheel hub 1, so that the wheel hub 1 and the two baffles 2 form the frame of the Mecanum omnidirectional wheel. All roller bodies 3 are arranged equidistantly around the axial direction of the wheel hub 1, and the two baffles 2 are provided with mounting grooves 22 for placing the ends of the roller bodies 3. A connecting shaft 4 is penetrated inside the roller body 3, and fasteners 41 are detachably connected to the two ends of the connecting shaft 4. When the roller body 3 is placed in the mounting groove 22, the connecting shaft 4 is located between the two baffles 2. At this time, the two fasteners 41 are used to fix the connecting shaft 4 and the two baffles 2. Among them, the two ends of the connecting shaft 4 can fit with the baffles 2, or a certain gap can be left. When removing the roller body 3, the two fasteners 41 are first separated from the connecting shaft 4, and the roller body 3 and the connecting shaft 4 located between the two baffles 2 can be directly taken out from the mounting groove 22, so that the roller body 3 and the hub 1 can be separated without separating the connecting shaft 4 and the roller body 3, thereby facilitating the replacement of the roller body 3.

[0034] Reference Figure 1 , Figure 4 and Figure 5In this embodiment, the fastener 41 can be a fastening screw, and of course, the connecting shaft 4 and the fastener 41 can also be connected by other detachable connection methods such as riveting. In order to increase the fastening force between the connecting shaft 4 and the two fasteners 41, the connection between the connecting shaft 4 and the fastener 41 is coated with thread glue.

[0035] Reference Figure 1 and Figure 2 , all rollers 3 are spindle-shaped, and the rollers 3 placed in the mounting groove 22 are rotatably connected to the wheel hub 1. The axis of the roller 3 and the axis of the wheel hub 1 are 45°. When assembled, the Mecanum omnidirectional wheels are symmetrical in pairs, and the axes of the rollers 3 of all Mecanum omnidirectional wheels point to the center of the chassis, so the envelope formed by all rollers 3 is circular. During the rotation of the Mecanum omnidirectional wheel, the friction between the roller 3 and the ground will generate friction, and the direction of the friction is opposite to the axial direction of the roller 3, so the friction force on the Mecanum omnidirectional wheel is 45° to the direction of the roller 3, so it can achieve omnidirectional movement.

[0036] Reference Figure 1 and Figure 4 , both ends of the roller body 3 are embedded with a combined bearing 31. In this embodiment, the combined bearing 31 is preferably a needle roller-thrust cylindrical roller bearing, which can bear large axial loads and radial loads at the same time; and the end faces of the two combined bearings 31 protrude from the end faces of the roller body 3. Abutments 32 are provided on both sides of the two roller bodies 3. The two ends of the two abutments 32 abut against the combined bearing 31 and the baffle 2 respectively. The two abutments 32 are sleeved on the connecting shaft 4 to make up for the gap between the roller body 3 and the baffle 2 when installing. In this embodiment, the abutment 32 is preferably a spring washer or a wave spring. The abutment 32 can offset the accumulated tolerance generated during processing and transfer to remove the installation gap and reduce noise. In addition, the outside of the roller body 3 is coated with a protective layer 33. In this embodiment, the protective layer 33 is preferably polyurethane rubber. The protective layer 33 can reduce the wear of the roller body 3 and also reduce noise.

[0037] Reference Figure 1 and Figure 6 The two baffles 2 are located on both sides of the hub 1, and a plurality of threaded holes 21 are provided on the two baffles 2, so that it is convenient to connect the baffles 2 with other components. In addition, the hub 1 can select different connection modes such as key connection or flange connection according to different driving parts, so as to facilitate assembly and use.

[0038] Reference Figure 1 and Figure 5 The wheel hub 1 and the baffle 2 are provided with a plurality of positioning holes 23, into which positioning pins can be inserted. The positioning holes 23 and the positioning pins inserted therein can increase the accuracy of the position of the wheel hub 1 and the two baffles 2 during assembly, and the positioning pins can provide shear resistance, thereby increasing the performance of the Mecanum omnidirectional wheel.

[0039] A method for assembling the above-mentioned Mecanum omnidirectional wheel comprises the following steps: S1, establishing a reference system including a "top" reference surface, a "middle" reference surface, and a "bottom" reference surface according to the width direction of the Mecanum omnidirectional wheel; the "top" reference surface, the "middle" reference surface, and the "bottom" reference surface are arranged in parallel in sequence, the "top" reference surface and the "bottom" reference surface respectively correspond to the planes where the two ends of the Mecanum omnidirectional wheel are located, and the "middle" reference surface is located in the middle of the "top" reference surface and the "bottom" reference surface;

[0040] S2. Establishing a reference axis in the “middle” reference plane, wherein the reference axis is 45° to the “middle” reference plane;

[0041] S3, establishing a "side" reference surface passing through the reference axis, used as a rotation reference surface;

[0042] S4, drawing the envelope of the Mecanum omnidirectional wheel on the “top” reference surface, the “middle” reference surface, and the “bottom” reference surface;

[0043] S5, drawing the envelope surface of the roller body on the “side” reference surface to rotate and form the roller body;

[0044] S6, arranging all the rollers and determining the force-bearing overlap areas of the rollers;

[0045] S7. Set a compensation value according to the stress overlap area of ​​the roller body, and the compensation value is the distance from the maximum outer diameter of the roller body in the direction away from the reference system, so that the envelope line is located within the range of the adjacent envelope surface. The structure of the roller body is a spindle, so the bearing capacity of its narrow side is low. The envelope surface formed by the roller body on the "side" reference surface, and the envelope line of the Mecanum omnidirectional wheel is drawn on the "top" reference surface, "middle" reference surface, and "bottom" reference surface. In theory, the envelope line should be located inside the above-mentioned envelope surface, thereby reducing the stress concentration formed on the narrow side of the roller body.

[0046] Reference Figure 2 and Figure 3 In this embodiment, the outer part of the roller body is covered with a protective layer. At this time, because the protective layer covering the narrow side of the roller body is thin, the load bearing capacity of the narrow side of the roller body is reduced, causing the protective layer covering the narrow side of the roller body to deform greatly in the radial direction. At the same time, because the stress concentration points are mainly concentrated on the narrow side of the roller body during the operation of the Mecanum omnidirectional wheel, the protective layer covering the narrow side of the roller body is prone to local temperature increase under the action of stress concentration, causing the protective layer to fall off.

[0047] Reference Figure 2 and Figure 3According to the actual assembly, the wide side of the Mecanum omnidirectional wheel usually protrudes a certain amount relative to the narrow side. At the same time, the compensation value can be set in combination with the force overlap area of ​​adjacent rollers. The force overlap area of ​​adjacent rollers is Figure 3 The shaded part indicates Figure 3 The shadow on a single roller indicates the independent load-bearing area of ​​a single roller; the compensation value in this embodiment ranges from 0.5 mm to 3 mm. The envelope line is adjusted to be located inside the envelope surface by using the compensation value, so that the envelope surface of each roller of the Mecanum omnidirectional wheel forms an integral outer circle, thereby reducing the stress concentration formed by the narrow edge of the roller.

[0048] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A Mecanum omnidirectional wheel, characterized in that: It comprises a wheel hub, two baffles and a plurality of roller bodies, wherein the two baffles are respectively fixed to the two end surfaces of the wheel hub; the roller body is arranged around the axial direction of the wheel hub, and the axis of the roller body is 45° with the axis of the roller body; the roller body is rotatably connected with the two baffles through a connecting shaft, and fasteners are detachably arranged at both ends of the connecting shaft, and the fasteners can fix the connecting shaft and the two baffles; the outside of the roller body is covered with a protective layer; The assembly method of the omnidirectional wheel comprises the following steps: S1. Establish a reference system including a "top" reference surface, a "middle" reference surface, and a "bottom" reference surface according to the width direction of the Mecanum omnidirectional wheel; S2. Establish a reference axis in the "middle" reference plane, wherein the reference axis is 45° to the "middle" reference plane; S3, establishing a "side" reference surface passing through the reference axis, used as a rotation reference surface; S4, drawing the envelope of the Mecanum omnidirectional wheel on the "top" reference surface, the "middle" reference surface, and the "bottom" reference surface; S5, drawing the envelope surface of the roller body on the "side" reference surface to rotate and form the roller body; S6, arranging all the rollers and determining the force-bearing overlap areas of the rollers; S7, setting a compensation value according to the force overlap area of ​​the roller body, the compensation value being the distance from the maximum outer diameter of the roller body in the direction away from the reference system, so that the envelope line is located within the range of the adjacent envelope surface; the compensation value is 0.5 mm-3 mm; Combined bearings are embedded at both ends of the roller body, and the end faces of the combined bearings protrude from the end faces of the roller body; the combined bearings are needle roller-thrust cylindrical roller bearings; Abutment members are provided on both sides of the roller body, and the two ends of the abutment members are respectively in contact with the combined bearing and the blocking sheet to make up for the installation gap; The abutment member is a spring washer or a wave spring.

2. The Mecanum omnidirectional wheel according to claim 1, characterized in that: The connection between the connecting shaft and the fastener is coated with thread glue.

3. The Mecanum omnidirectional wheel according to claim 1, characterized in that: A plurality of threaded holes are provided on the two baffles, and the hub can be key-connected or flange-connected to the driving member.

4. The Mecanum omnidirectional wheel according to claim 1, characterized in that: A plurality of positioning holes are provided on the wheel hub and the two baffles.

5. A method for assembling the Mecanum omnidirectional wheel according to claim 1, characterized in that: The following steps are involved: S1. Establish a reference system including a "top" reference surface, a "middle" reference surface, and a "bottom" reference surface according to the width direction of the Mecanum omnidirectional wheel; S2. Establish a reference axis in the "middle" reference plane, wherein the reference axis is 45° to the "middle" reference plane; S3, establishing a "side" reference surface passing through the reference axis, used as a rotation reference surface; S4, drawing the envelope of the Mecanum omnidirectional wheel on the "top" reference surface, the "middle" reference surface, and the "bottom" reference surface; S5, drawing the envelope surface of the roller body on the "side" reference surface to rotate and form the roller body; S6, arranging all the rollers and determining the force-bearing overlap areas of the rollers; S7. Set a compensation value according to the force overlap area of ​​the roller body, wherein the compensation value is the distance from the maximum outer diameter of the roller body in the direction away from the reference system, so that the envelope line is located within the range of the adjacent envelope surface.

6. An assembly method according to claim 5, characterized in that: In step S7, the compensation value is 0.5 mm-3 mm.

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