A low-cost omni-wheel and a mobile tool using the same

Abstract

The application discloses a low-cost omni-directional wheel and a mobile tool using the same, and belongs to the field of omni-directional wheels. The low-cost omni-directional wheel comprises a rolling body assembly and a hub assembly, the rolling body assembly comprises a rolling body and a bearing support, a plurality of rolling body assemblies are circumferentially arranged on the outer periphery of the hub assembly, the rolling bodies of adjacent rolling body assemblies are connected end to end, the outer contour generatrix m of each rolling body is located on the same envelope circle O, and the rolling body matching coefficient of the low-cost omni-directional wheel is 0.035-0.06. The number of the rolling bodies of the omni-directional wheel and the size of the rolling bodies are considered by reasonably optimizing the rolling body matching coefficient of the omni-directional wheel, the number of the rolling bodies of the omni-directional wheel is reasonably reduced under the condition that the overall thickness size of the omni-directional wheel is moderate, the manufacturing cost of the omni-directional wheel is reduced, the repeated assembling process of the rolling bodies is reduced, the assembling and manufacturing efficiency of the omni-directional wheel is improved, and the obstacle passing performance of the omni-directional wheel during lateral rolling is improved.

Description

Technical Field

[0001] This invention relates to an omnidirectional wheel, and more specifically, to a low-cost omnidirectional wheel and a mobility tool using the omnidirectional wheel. Background Technology

[0002] Omnidirectional wheels are wheels that can move in different directions. They can roll axially like normal wheels or move laterally using the rolling elements on the wheel, achieving two degrees of freedom of movement: axial rotation and lateral movement. They have advantages such as flexible movement and small turning radius, and are widely used in robots, trolleys, small vehicles and electric wheelchairs to achieve small-radius steering.

[0003] Common omnidirectional wheels include Mecanum wheels, double-row omnidirectional wheels, and single-row omnidirectional wheels. Mecanum wheels consist of small wheels arranged at a certain angle to form a large wheel. Their main drawback is the inclined and spaced distribution of the small wheels (rolling elements), which makes them prone to vibration during axial rotation. Double-row omnidirectional wheels have two rows of staggered rollers (rolling elements) on the hub. The outer circle fitted by the two rows of rollers also has a polygonal structure, resulting in bumps during movement. Furthermore, their structure is relatively complex, thicker, and occupies more space. Single-row omnidirectional wheels utilize small wheels (rolling elements) enclosing a complete circle around the outer circumference of the hub. Their structure is more compact, with less vibration during axial rotation and greater flexibility in lateral movement. They are widely used, especially in applications such as electric wheelchairs where comfort and steering flexibility are crucial.

[0004] One drawback of existing single-row omnidirectional wheels is their high manufacturing cost. To utilize the small wheels (rolling elements) to envelop the hub and form a complete circular wheel, a large number of small wheel components are required. This not only leads to cumbersome assembly operations but also significantly increases the manufacturing cost of the omnidirectional wheel. For example, the "novel omnidirectional wheel structure" disclosed in Chinese Patent Application No. 201210202379.5 solves the problem of excessive roller clearance and significant vibration during rolling in general omnidirectional wheels. This omnidirectional wheel has 16 support seats, with a driven wheel (rolling element) installed on each two adjacent support seats, meaning the omnidirectional wheel consists of 16 rolling elements. This results in cumbersome assembly operations and high manufacturing costs. Similarly, the "omnidirectional wheel with multi-terrain adaptability" disclosed in Chinese Patent Application No. 201910239351.0 has 15 load-bearing supports, with a rolling element installed on each two adjacent load-bearing supports, meaning the omnidirectional wheel consists of 15 rolling elements. This also suffers from cumbersome assembly operations and high manufacturing costs. The main reason for the large number of rolling elements in existing single-row omnidirectional wheels is that each rolling element uses a two-end support structure. This necessitates designing the angle between the rotation axis of each rolling element and the tangent of the entire omnidirectional wheel to be as small as possible (the angle α between the axes of two adjacent rolling elements should be small). The number of rolling elements equals 360° divided by the angle α. Therefore, the number of rolling elements in the aforementioned omnidirectional wheels is determined by their structure and cannot be reduced. Consequently, it is difficult to reduce the assembly complexity and manufacturing cost of omnidirectional wheels by reducing the number of rolling elements. In addition, due to the large number of rolling elements in omnidirectional wheels and the limitations imposed by the design of the rolling element profile curves, the maximum diameter of the rolling elements is generally small, resulting in poor lateral rolling obstacle clearance of the omnidirectional wheel. The two-end support structure of the rolling elements requires repeated positioning during assembly, which demands high machining accuracy and also increases its manufacturing cost.

[0005] Chinese patent application No. 201710630644.2 discloses an "omnidirectional moving wheel" in which the rolling elements no longer adopt a two-end support structure, but instead divide the roller (rolling element) into two parts: a first wheel part and a second wheel part. The first wheel part and the second wheel part are respectively supported at both ends of a central support shaft of a set of support members, which is equivalent to using support members to support the middle of the roller. This omnidirectional wheel seems to overcome the problem of a large number of rollers due to the support at both ends of the roller, and can reduce the number of roller assemblies (it gives an embodiment of 12 roller assemblies). However, in reality, each roller is divided into two independently rotating rolling elements. The omnidirectional wheel only reduces the number of roller assemblies (or support members), while the number of rolling elements on the omnidirectional wheel increases (the number of rolling elements is twice the number of roller assemblies). At least two types of rolling elements need to be manufactured and assembled separately, which increases the assembly complexity and manufacturing cost of the omnidirectional wheel. Furthermore, since the two wheel parts of the roller rotate independently and are different sizes, although the diameter of the larger wheel part can be designed to be larger, its axial width is small, and the lateral rolling obstacle crossing ability is not substantially improved.

[0006] Furthermore, for single-row omnidirectional wheels, if the number of circumferentially distributed rolling elements is too small, the maximum outer diameter of the rolling elements will be too large due to limitations imposed by the design of the rolling element profile curve and the integrity of the omnidirectional wheel's envelope circle. This, in turn, will result in an excessively large overall thickness of the omnidirectional wheel, increasing the manufacturing costs of the hub, load-bearing bracket, and individual rolling elements, ultimately leading to an increase in the manufacturing cost of the omnidirectional wheel. Therefore, how to reasonably control the number of rolling elements in an omnidirectional wheel to reduce manufacturing costs and assembly difficulty, while simultaneously ensuring the omnidirectional wheel's load-bearing capacity, obstacle-crossing ability, and other performance characteristics, has become a design challenge that urgently needs to be addressed in this field. Summary of the Invention

[0007] 1. The technical problem that the invention aims to solve

[0008] The purpose of this invention is to overcome the shortcomings of existing omnidirectional wheels, such as high manufacturing costs, and to provide a low-cost omnidirectional wheel and a mobile tool using the same wheel. By optimizing the rolling element ratio of the omnidirectional wheel, the invention balances the number and size of the rolling elements, reducing the number of rolling elements while maintaining a moderate overall thickness. This lowers the manufacturing cost and reduces repetitive assembly steps, improving assembly efficiency. Furthermore, compared to existing omnidirectional wheels, the maximum diameter of the rolling elements is larger, improving obstacle-crossing capability during lateral rolling while maintaining load-bearing capacity.

[0009] This invention further simplifies the manufacturing and assembly process of omnidirectional wheels by optimizing the structure, materials, manufacturing and assembly processes of the rolling element assembly and hub assembly, thereby reducing the manufacturing cost and difficulty of omnidirectional wheels and significantly improving their market competitiveness.

[0010] 2. Technical Solution

[0011] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0012] The present invention provides a low-cost omnidirectional wheel, comprising:

[0013] A rolling element assembly, the rolling element assembly including rolling elements and a support bracket, the rolling elements being rotatably mounted on one side of the support bracket;

[0014] A hub assembly, wherein a plurality of rolling element assemblies are installed in a circular arrangement on the outer periphery of the hub assembly, and the bearing brackets of each rolling element assembly are installed on the hub assembly. The rolling elements of adjacent rolling element assemblies are connected end to end, so that the outer contour generatrix m of each rolling element is located on the same envelope circle O.

[0015] The rolling element ratio coefficient of this low-cost omnidirectional wheel is 0.035 to 0.06. The rolling element ratio coefficient is the ratio of the number of rolling elements in the omnidirectional wheel to the diameter of the envelope circle O, where the diameter of the envelope circle O is in millimeters.

[0016] Furthermore, the included angle α between adjacent rolling element axes is 24° to 40°.

[0017] Furthermore, when the diameter of the envelope circle O is 8 inches, the number of rolling elements in the omnidirectional wheel is 9 to 10;

[0018] When the diameter of the envelope circle O is 9 inches, the number of rolling elements in the omnidirectional wheel is 9 to 12.

[0019] When the diameter of the envelope circle O is 10 inches, the number of rolling elements in the omnidirectional wheel is 10 to 13.

[0020] When the diameter of the envelope circle O is 12 inches, the number of rolling elements in the omnidirectional wheel is 11 to 14.

[0021] When the diameter of the envelope circle O is 13 inches, the number of rolling elements in the omnidirectional wheel is 12 to 15.

[0022] Furthermore, adjacent rolling elements are fitted with a clearance fit end to end, and the axes of each rolling element are located in the plane containing the envelope circle O; the generatrix m of the rolling element is an arc, and the outer diameter of the rolling element gradually increases from one end to the other along the axial direction; the large-diameter end of the rolling element has an inwardly recessed receiving groove, and the bearing bracket has a shaft mounting portion that is accommodated in the receiving groove of the rolling element; the side of the bearing bracket away from the shaft mounting portion also has a clearance groove for accommodating the small-diameter end of the adjacent rolling element.

[0023] Furthermore, the support bracket is an injection molded or die-cast part, and a cantilever shaft is integrally connected to the shaft mounting part of the support bracket through injection molding or die casting process, and the shaft hole part of the rolling element is mounted on the cantilever shaft by the cantilever end.

[0024] Furthermore, the rolling element's shaft hole portion is rotatably fitted to the cantilever shaft via a bushing, and the rolling element and the cantilever shaft are axially limited by an end-face wear-resistant washer sleeved on the cantilever shaft. The cantilever shaft is also provided with an elastic washer for pressing the end-face wear-resistant washer.

[0025] Furthermore, the bushing and rolling element are sequentially fitted onto the cantilever shaft from the cantilever end and locked in place by axial fasteners; the end face wear-resistant washer includes a first wear-resistant washer and a second wear-resistant washer, the first wear-resistant washer and the second wear-resistant washer are disposed between the axial fastener and one end face of the shaft hole, and the elastic washer is disposed between the first wear-resistant washer and the second wear-resistant washer.

[0026] Furthermore, the elastic washer is a wave washer, and the bushing is a powder metallurgy oil-impregnated bushing; the rolling element has a countersunk hole on the side near the cantilever end of the cantilever shaft for accommodating axial fasteners.

[0027] Furthermore, the support bracket is injection molded from glass fiber reinforced nylon or die-cast from aluminum alloy, and has several material reduction grooves at the shaft mounting position on the support bracket.

[0028] Furthermore, the rolling element includes an inner core and a tread, with the tread covering the inner core. The inner core is injection molded from glass fiber reinforced nylon, and the tread is made of an elastic and wear-resistant material. Several annular grooves are also provided on the outer wall of the tread.

[0029] Furthermore, the hub assembly includes a hub mounting sleeve and flange plates disposed at both ends of the hub mounting sleeve. One or both ends of the hub mounting sleeve are fitted with the corresponding flange plates by means of shaft hole sleeve positioning. The outer periphery of the flange plate is fixedly connected to the bearing bracket of the corresponding rolling element assembly by a first fastener.

[0030] Furthermore, after the central portion of the flange plate is axially positioned on the hub mounting sleeve, there is a distance ΔH between the outer periphery of the flange plate and the contact surface of the bearing bracket, such that the central portion of the flange plate, after being locked to the bearing bracket by the first fastener, arches slightly outward; or,

[0031] The distance H1 between the two ends of the hub mounting sleeve and the axial positioning surface of the flange plate is 2×ΔH greater than the distance H2 between the two sides of the bearing bracket and the positioning contact surface of the flange plate. The flange plate is a flat plate structure, and the middle of the flange plate is slightly arched outward after being locked with the bearing bracket by the first fastener.

[0032] Furthermore, the end of the hub mounting sleeve is provided with a positioning ring platform, the inner side of the positioning ring platform has a ring platform positioning surface, the middle of the flange plate has a center hole that is clearance-fitted with the positioning ring platform, the center hole of the flange plate is sleeved on the positioning ring platform on the corresponding side, and the center of the flange plate is axially positioned by the ring platform positioning surface.

[0033] The flange plate has several connecting arms arranged radially around its outer periphery. The two sides of the bearing bracket are respectively provided with positioning grooves that cooperate with the connecting arms. The inner side of the positioning groove has an abutment surface that contacts the connecting arm. The abutment surface of the positioning groove is provided with a connecting hole. The connecting arm is provided with a corresponding through hole. The first fastener passes through the through hole and is screwed into the corresponding connecting hole to realize the connection between the connecting arm and the bearing bracket. The first fastener is a self-tapping screw.

[0034] Furthermore, when the omnidirectional wheel is used as a driven wheel, a pair of bearings are provided inside the hub mounting sleeve, and the two bearings are positioned by a spacer sleeve; when the omnidirectional wheel is used as a drive wheel, the center of the hub mounting sleeve has a drive shaft hole, and the hub mounting sleeve is connected to the flange plate at the corresponding end by a second fastener.

[0035] A mobility tool according to the present invention includes the aforementioned low-cost omnidirectional wheel.

[0036] Furthermore, the mobility tool can be an electric wheelchair, a small vehicle, a transport trolley, or a walking robot.

[0037] 3. Beneficial effects

[0038] Compared with existing known technologies, the technical solution provided by this invention has the following significant advantages:

[0039] (1) A low-cost omnidirectional wheel of the present invention includes a rolling element assembly and a hub assembly. The rolling element ratio coefficient is 0.035 to 0.06. Through reasonable optimization design of the rolling element ratio coefficient of the omnidirectional wheel, the number of rolling elements and the size of the rolling elements themselves are taken into account. While ensuring that the overall thickness of the omnidirectional wheel is moderate, the number of rolling elements of the omnidirectional wheel is reasonably reduced, the manufacturing cost of the omnidirectional wheel is reduced, and the repeated assembly process of the rolling elements is reduced, thereby improving the assembly and manufacturing efficiency of the omnidirectional wheel. Moreover, compared with the existing omnidirectional wheel, the maximum diameter of the rolling elements is larger, which improves the obstacle crossing ability of the omnidirectional wheel when rolling laterally, while also taking into account the load-bearing capacity of the omnidirectional wheel.

[0040] (2) The present invention provides a low-cost omnidirectional wheel with an included angle α between adjacent rolling element axes of 24° to 40°. While reasonably reducing the number of rolling elements in the omnidirectional wheel, it can ensure the load-bearing capacity of the bearing bracket for the rolling elements. In addition, the number of rolling elements increases reasonably as the wheel diameter of the omnidirectional wheel increases. While effectively controlling the manufacturing cost of the omnidirectional wheel, it also takes into account the reasonable thickness of the omnidirectional wheel and the various performances of the omnidirectional wheel such as load-bearing and obstacle crossing.

[0041] (3) A low-cost omnidirectional wheel of the present invention has adjacent rolling elements with a clearance fit at their ends, and the axes of each rolling element are located in the plane containing the envelope circle O; the generatrix m of the rolling element is an arc, and the outer diameter of the rolling element gradually increases from one end to the other along the axial direction; the large diameter end of the rolling element has an inwardly recessed receiving groove, and the bearing bracket has a shaft mounting part that is accommodated in the receiving groove of the rolling element; the side of the bearing bracket away from the shaft mounting part also has a clearance groove for accommodating the small diameter end of the adjacent rolling element; with this design, the omnidirectional wheel has a complete outer circumference and rolls smoothly;

[0042] (4) A low-cost omnidirectional wheel of the present invention has a bearing bracket that is an injection molded part or a die-cast part. The bearing bracket has a cantilever shaft integrally connected to the shaft mounting part by injection molding or die casting process. The shaft hole part of the rolling element is installed on the cantilever shaft by the cantilever end. The connection structure between the cantilever shaft and the bearing bracket is simple, firm and reliable, and it is easy to ensure the position and dimensional accuracy requirements of both. It can reduce the manufacturing process and reduce the manufacturing cost.

[0043] (5) A low-cost omnidirectional wheel of the present invention has a rolling element with a shaft hole and a cantilever shaft through a bushing rotational fit. The rolling element and the cantilever shaft are axially limited by an end face wear-resistant washer sleeved on the cantilever shaft. The cantilever shaft is also provided with an elastic washer for pressing the end face wear-resistant washer. Compared with the existing deep groove ball bearings, the bushing is used as the rolling element, which is simple and convenient to assemble and has a lower cost. The elastic washer can keep the two ends of the rolling element in a tight fit, thereby eliminating the axial clearance and avoiding noise or abnormal sound caused by axial movement of the rolling element. It can also play a sealing role, reducing the intrusion of dust and water vapor into the internal rolling sliding surface and causing wear and damage.

[0044] (6) A low-cost omnidirectional wheel of the present invention has a bushing and a rolling element that are sequentially sleeved on the rotating shaft from the cantilever end of the rotating shaft and locked and fixed by axial fasteners. Wear-resistant washers and elastic washers are also provided at the cantilever end of the rotating shaft, so that the rolling element and the rotating shaft are simple and convenient to assemble and the rolling element rotates smoothly and reliably.

[0045] (7) A low-cost omnidirectional wheel of the present invention has a bushing made of powder metallurgy oil-impregnated bushing. The bushing has good self-lubricating effect, effectively reducing the rolling noise and reducing the manufacturing cost. The side of the rolling element near the cantilever end of the cantilever shaft has a countersunk hole for accommodating axial fasteners, which ensures the structural compactness of the rolling element assembly and facilitates the assembly of the omnidirectional wheel.

[0046] (8) A low-cost omnidirectional wheel of the present invention has a bearing bracket made of glass fiber reinforced nylon by injection molding or aluminum alloy by die casting. The rolling element assembly has high structural strength and light weight. The bearing bracket is simple and convenient to form and has low manufacturing cost. The bearing bracket has several material reduction grooves at the position of the shaft mounting part. The material reduction grooves can not only reduce the use of materials, but also make the wall thickness of the bearing bracket uniform, reduce injection molding or die casting defects, and improve the manufacturing accuracy of the parts.

[0047] (9) A low-cost omnidirectional wheel of the present invention has a rolling element comprising an inner core and a tread, the tread covering the inner core, the inner core being injection molded from glass fiber reinforced nylon, and the tread being made of elastic wear-resistant material. Several annular grooves are also provided on the outer wall of the tread. The rolling element structure has high strength and light weight, and is simple and convenient to manufacture. The annular grooves on the tread can play a role in anti-slip and material reduction, and can also change the uniformity of the periodic vibration frequency of the gap at the junction of two adjacent rolling elements when rolling in a circular motion, thereby changing the vibration and noise frequency and improving the comfort of human senses.

[0048] (10) A low-cost omnidirectional wheel of the present invention includes a hub assembly comprising a hub mounting sleeve and flange plates disposed at both ends of the hub mounting sleeve. One or both ends of the hub mounting sleeve are fitted with the flange plates at the corresponding ends by a shaft hole sleeve for positioning. The outer periphery of the flange plate is fixedly connected to the bearing bracket of the corresponding rolling element assembly by a first fastener. The flange plates are used to assemble each rolling element assembly, and the hub mounting sleeve is used to axially position and support the flange plates. The hub mounting sleeve, the flange plates at both ends and each set of rolling element assemblies can be assembled together simply and quickly to form an omnidirectional wheel overall structure. The assembly process is simple and convenient, and the manufacturing cost of the omnidirectional wheel can be effectively reduced.

[0049] (11) A low-cost omnidirectional wheel of the present invention has a flange plate whose center is axially positioned on the hub mounting sleeve. The flange plate has a gap ΔH between its outer periphery and the contact surface of the bearing bracket, so that the center of the flange plate is slightly arched outward after being locked with the bearing bracket by the first fastener; or, the distance H1 between the two ends of the hub mounting sleeve and the axial positioning surface of the center of the flange plate is 2×ΔH larger than the distance H2 between the two sides of the bearing bracket and the positioning contact surface of the outer periphery of the flange plate. The flange plate is a flat plate structure, and the center of the flange plate is slightly arched outward after being locked with the bearing bracket by the first fastener. In this way, the center of the flange plate after installation can be slightly arched outward, which not only makes the locking firm and reliable, but also ensures that the flange plate and the hub mounting sleeve are stably and reliably connected, and improves the pressure resistance of the flange plate and the overall load-bearing capacity of the omnidirectional wheel.

[0050] (12) A low-cost omnidirectional wheel of the present invention has a positioning ring platform at the end of the hub mounting sleeve, the inner side of the positioning ring platform has a ring platform positioning surface, the middle part of the flange plate has a center hole that is clearance-fitted with the positioning ring platform, the center hole of the flange plate is sleeved on the positioning ring platform on the corresponding side, and the center of the flange plate is axially positioned by the ring platform positioning surface. The assembly structure of the hub mounting sleeve and the flange plate is simple and easy to process and manufacture.

[0051] (13) A low-cost omnidirectional wheel of the present invention has a flange plate with a plurality of connecting arms distributed radially in a circular pattern on the outer periphery. The two sides of the bearing bracket are respectively provided with positioning grooves that cooperate with the connecting arms. The inner side of the positioning groove has an abutment surface that contacts the connecting arm for positioning. The connecting arm and the bearing bracket are fixedly connected by self-tapping screws. The positioning groove improves the stability of the connection with the connecting arm, which can be conveniently positioned and assembled with the corresponding bearing bracket. It facilitates the transmission of force from the rolling element assembly to the flange plate and reduces the shearing effect on the self-tapping screw. Furthermore, the self-tapping screw connection makes the connection operation simple and convenient, and the processing and manufacturing costs are lower.

[0052] (14) The present invention provides a low-cost omnidirectional wheel that can be used as a driving wheel or as a drive wheel. It has a wide range of applications, strong practicality, and good economy.

[0053] (15) A mobile tool of the present invention is equipped with the above-mentioned low-cost omnidirectional wheel, which makes the mobile tool flexible and convenient to turn, further reduces the cost of the mobile tool, and can greatly improve the market competitiveness of the mobile tool using the omnidirectional wheel. Attached Figure Description

[0054] Figure 1 This is a three-dimensional structural diagram of a low-cost omnidirectional wheel according to the present invention;

[0055] Figure 2 This is a three-dimensional structural diagram of a low-cost omnidirectional wheel of the present invention after omitting part of the rolling element assembly;

[0056] Figure 3 This is a partial cross-sectional view of a low-cost omnidirectional wheel according to the present invention.

[0057] Figure 4 This is a schematic diagram of the layout structure of the support bracket and cantilever shaft on the hub assembly in this invention;

[0058] Figure 5 This is a three-dimensional structural diagram of the rolling element assembly at one angle in this invention;

[0059] Figure 6 This is a three-dimensional structural diagram of the rolling element assembly from another angle in this invention;

[0060] Figure 7 This is a cross-sectional view of the rolling element assembly in this invention;

[0061] Figure 8 This is a schematic diagram of the support structure in the rolling element assembly of the present invention;

[0062] Figure 9 This is a schematic diagram of the disassembled structure of the rolling element assembly in this invention;

[0063] Figure 10This is a schematic diagram of the disassembled structure of a low-cost omnidirectional wheel hub assembly according to the present invention;

[0064] Figure 11 This is a front view schematic diagram of a low-cost omnidirectional wheel according to the present invention;

[0065] Figure 12 for Figure 11 Enlarged view of a partial sectional section;

[0066] Figure 13 This is a schematic diagram showing the disassembled state of a low-cost omnidirectional wheel hub assembly according to the present invention;

[0067] Figure 14 This is a schematic diagram of the combined state of a low-cost omnidirectional wheel hub assembly according to the present invention;

[0068] Figure 15 This is a cross-sectional schematic diagram of the combined state of a low-cost omnidirectional wheel hub assembly according to the present invention;

[0069] Figure 16 This is a three-dimensional structural schematic diagram of another embodiment of a low-cost omnidirectional wheel according to the present invention;

[0070] Figure 17 This is a schematic diagram of the hub split state in another embodiment of a low-cost omnidirectional wheel of the present invention.

[0071] Explanation of the labels in the diagram:

[0072] 10. Rolling element assembly; 11. Rolling element; 11a. Inner core; 11b. Tread; 11-1. Receiving groove; 11-2. Annular groove; 11-3. Shaft hole; 11-4. Countersunk hole; 12. Bearing bracket; 12-1. Shaft mounting part; 12-2. Connecting part; 12-3. Positioning groove; 12-3a. Abutment surface; 12-4. Connecting hole; 12-5. Clearance groove; 12-6. Subtractive material groove; 13. Axial fastener; 14. Cantilever shaft; 14-1. Fastening hole; 14-2. Insert groove; 14-3. Anti-rotation part; 15. Bushing; 16. First wear-resistant washer; 17. Second wear-resistant washer; 18. Elastic washer;

[0073] 20. Hub assembly; 21. Hub mounting sleeve; 21-1. Positioning ring platform; 21-1a. Ring platform positioning surface; 21-2. Drive shaft hole; 22. Flange plate; 22-1. Connecting arm; 22-1a. Through hole; 22-2. Center hole; 23. First fastener; 24. Bearing; 25. Spacer; 26. Second fastener. Detailed Implementation

[0074] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments.

[0075] [Example]

[0076] Combination Figures 1 to 4 As shown, this embodiment of a low-cost omnidirectional wheel includes a rolling element assembly 10 and a hub assembly 20. The rolling element assembly 10 includes rolling elements 11 and a support bracket 12. The rolling elements 11 are rotatably mounted on one side of the support bracket 12. A plurality of rolling element assemblies 10 are circumferentially distributed around the outer periphery of the hub assembly 20. The support brackets 12 of each rolling element assembly 10 are mounted on the hub assembly 20. The rolling elements 11 of adjacent rolling element assemblies 10 are connected end to end, so that the generatrix m of the outer contour of each rolling element 11 is located on the same envelope circle O. The omnidirectional wheel composed of multiple sets of rolling element assemblies 10 can roll axially around the hub assembly 20 and can also move laterally using the rolling elements 11. Under the same omnidirectional wheel diameter, the more rolling element assemblies 10 or rolling elements 11 there are, the higher the manufacturing cost of the omnidirectional wheel and the more complicated the assembly process. The fewer rolling element assemblies 10 or rolling elements 11 there are, the larger the maximum outer diameter of the rolling elements 11 and the larger the thickness of the omnidirectional wheel, which also increases the manufacturing cost. Therefore, the key to reducing the manufacturing cost of omnidirectional wheels lies in how to reasonably reduce the number of rolling elements 11 while taking into account all performance characteristics. This invention introduces the concept of a "rolling element ratio coefficient" for the first time. The rolling element ratio coefficient refers to the ratio of the number of rolling elements 11 in the omnidirectional wheel to the diameter of the envelope circle O, where the diameter of the envelope circle O is in millimeters (mm). The diameter of the envelope circle O is the wheel diameter of the omnidirectional wheel. When designing an omnidirectional wheel, given the target wheel diameter D, multiplying the target wheel diameter D by the rolling element ratio coefficient λ yields the number of rolling elements n (n is a positive integer). After extensive design verification, this invention concludes that the optimal rolling element ratio for an omnidirectional wheel is 0.035–0.06. This ratio balances the number and size of the rolling elements, effectively reducing the number of rolling elements while maintaining a moderate overall thickness. This lowers manufacturing costs, reduces repetitive assembly steps, and improves assembly efficiency. Furthermore, compared to existing omnidirectional wheels, the maximum diameter of the rolling elements is larger, enhancing obstacle-crossing capability during lateral rolling while maintaining load-bearing capacity.

[0077] catch Figures 1 to 4As shown, in this embodiment, the low-cost omnidirectional wheel has an included angle α between the axes of adjacent rolling elements 11 of 24° and 40°. Generally, the included angle α between the axes of adjacent rolling elements 11 in an omnidirectional wheel is equal. In this case, the number of rolling elements n is equal to 360° divided by the included angle α, that is, the preferred number of rolling elements is 9 to 15. The specific number of rolling elements 11 can be selected by combining the above-mentioned rolling element ratio coefficient and the design wheel diameter of the omnidirectional wheel. In this way, it is possible to avoid the included angle α being too large, which would affect the load-bearing capacity of the support bracket 12 and the lateral rolling performance of the rolling elements 11. While reasonably reducing the number of rolling elements in the omnidirectional wheel, the load-bearing capacity of the support bracket 12 for the rolling elements 11 can be guaranteed.

[0078] Based on the design principles of omnidirectional wheels described above, the manufacturing cost of omnidirectional wheels can be reduced by reasonably decreasing the number of rolling elements 11, resulting in a low-cost omnidirectional wheel. For omnidirectional wheels of common sizes, the preferred design number of rolling elements is as follows:

[0079] When the diameter of the enveloping circle O is 8 inches (8-inch omnidirectional wheel), the number of rolling elements 11 in the omnidirectional wheel is 9-10; when the diameter of the enveloping circle O is 9 inches (9-inch omnidirectional wheel), the number of rolling elements 11 is 9-12; when the diameter of the enveloping circle O is 10 inches (10-inch omnidirectional wheel), the number of rolling elements 11 is 10-13; when the diameter of the enveloping circle O is 12 inches (12-inch omnidirectional wheel), the number of rolling elements 11 is 11-14; and when the diameter of the enveloping circle O is 13 inches (13-inch omnidirectional wheel), the number of rolling elements 11 is 12-15. It can be seen that the number of rolling elements 11 increases reasonably with the increase of the omnidirectional wheel diameter. This allows for effective control of the manufacturing cost of the omnidirectional wheel while also considering the reasonable thickness dimensions and the load-bearing, obstacle-crossing, and other performance characteristics of the omnidirectional wheel.

[0080] To further reduce the manufacturing cost and difficulty of omnidirectional wheels and enhance their market competitiveness, this invention, in addition to reducing manufacturing costs by rationally setting the number of rolling elements, also simplifies the manufacturing and assembly process of omnidirectional wheels through optimized design of the structure, materials, and manufacturing and assembly processes of the rolling element assembly 10 and the hub assembly 20, thereby reducing the manufacturing cost and difficulty of omnidirectional wheels. The specific design is as follows:

[0081] Reference Figures 1 to 4 and combined Figure 5 and Figure 6As shown, in this embodiment, the low-cost omnidirectional wheel has adjacent rolling elements 11 fitted end-to-end with a clearance fit, and the axes of each rolling element 11 are located in the plane containing the envelope circle O. The generatrix m of the rolling element 11 is an arc, meaning the outer contour of the rolling element 11 is a surface of revolution formed by rotating the arc generatrix m around its axis of rotation. The outer diameter of the rolling element 11 gradually increases from one end to the other along the axial direction. The large-diameter end of the rolling element 11 has an inwardly recessed receiving groove 11-1, and the support bracket 12 has a shaft mounting portion 12-1 that is accommodated within the receiving groove 11-1 of the rolling element 11. The side of the support bracket 12 away from the shaft mounting portion 12-1 also has a clearance groove 12-5 for accommodating the small-diameter ends of adjacent rolling elements 11. With this rolling element assembly 10 design, the omnidirectional wheel has a complete outer circumference, and each rolling element 11 can rotate freely and roll smoothly.

[0082] Reference Figures 7 to 9 As shown, the aforementioned support bracket 12 is an injection-molded or die-cast part. A cantilever shaft 14 is integrally connected to the shaft mounting portion 12-1 of the support bracket 12 via injection molding or die casting. The shaft hole portion 11-3 of the rolling element 11 is mounted on the cantilever shaft 14 from the cantilever end, allowing the rolling element 11 to rotate freely around the cantilever shaft 14. The cantilever shaft 14 can be machined separately, easily ensuring its dimensional accuracy. It is also directly injection-molded or die-cast and connected to the support bracket 12 as an insert. The connection structure between the cantilever shaft 14 and the support bracket 12 is simple, robust, and reliable, easily ensuring the positional and dimensional accuracy requirements of both, reducing manufacturing processes and costs. Specifically, during manufacturing, an insert groove 14-2 and an anti-rotation portion 14-3 (e.g., ...) can be machined at one end of the cantilever shaft 14. Figure 9 As shown, the inlay groove 14-2 can be several annular grooves to ensure that the cantilever shaft 14 and the bearing bracket 12 are axially and firmly connected. The anti-rotation part 14-3 can be a plane or groove located on the side to prevent the cantilever shaft 14 and the bearing bracket 12 from rotating relative to each other. After injection molding or die casting, the shaft mounting part 12-1 of the bearing bracket 12 tightly wraps around the end of the cantilever shaft 14 with the inlay groove 14-2 and the anti-rotation part 14-3, making the two an integral structure with high manufacturing precision and low manufacturing cost.

[0083] Reference Figure 7 and Figure 9As shown, the rolling element 11's shaft hole portion 11-3 is rotatably fitted to the cantilever shaft 14 via a bushing 15. The shaft hole portion 11-3 has a shaft hole that fits onto the cantilever shaft 14, and the bushing 15 is fitted onto the cantilever shaft 14 and located between the cantilever shaft 14 and the shaft hole portion 11-3. Compared to existing deep groove ball bearings, using the bushing 15 as the rolling element simplifies assembly, reduces costs, and makes it more convenient. Furthermore, the rolling element 11 and the cantilever shaft 14 are axially limited by an end-face wear-resistant washer fitted onto the cantilever shaft 14. The cantilever shaft 14 is also provided with an elastic washer 18 for pressing the end-face wear-resistant washer. The elastic washer 18 ensures that the two end faces of the rolling element 11 are in a tight fit, eliminating axial clearance and preventing noise or abnormal sounds caused by axial movement of the rolling element 11 during rolling. It also provides a sealing effect, reducing the intrusion of dust and moisture into the internal rolling sliding surface, thus preventing wear and damage. In practice, the bushing 15 and the rolling element 11 are sequentially fitted onto the cantilever shaft 14 from the cantilever end of the cantilever shaft 14 and locked in place by the axial fastener 13. The end face wear-resistant washers include a first wear-resistant washer 16 and a second wear-resistant washer 17, which are located between the axial fastener 13 and one end face of the shaft hole 11-3. An elastic washer 18 is located between the first wear-resistant washer 16 and the second wear-resistant washer 17, which can press the first wear-resistant washer 16 and the second wear-resistant washer 17 inward. All components are mounted from the cantilever end of the cantilever shaft 14, making the assembly of the rolling element 11 and the cantilever shaft 14 simple and convenient, and ensuring that the rolling element 11 rotates smoothly and reliably. The aforementioned elastic washer 18 is a corrugated washer, preferably made of existing 304 stainless steel. The cantilever shaft 14 can be machined from 1Cr13 martensitic stainless steel. Both the first wear-resistant washer 16 and the second wear-resistant washer 17 are stainless steel washers, which can prevent the internal rotating parts of the rolling element 11 from rusting and being damaged. The aforementioned axial fastener 13 can be a bolt with a pressure cap. A fastening hole 14-1 is provided at the cantilever end of the cantilever shaft 14. The fastening hole 14-1 has an internal thread, and the axial fastener 13 can be screwed onto the cantilever end of the cantilever shaft 14. The pressure cap is used to limit the position of the first wear-resistant washer 16. The bushing 15 is a powder metallurgy oil-impregnated bushing. The bushing has good self-lubricating effect, effectively reducing the rotation noise of the rolling element and reducing the manufacturing cost. As a preferred embodiment, the bushing 15 is a cylindrical sleeve structure, with one end abutting against the outer step of the shaft hole 11-3 and the other end abutting against the shoulder at the root of the cantilever shaft 14. The axial positioning of the rolling element 11 is achieved by using the axial fastener 13 and the wave washer. The side of the rolling element 11 near the cantilever end of the cantilever shaft 14 has a countersunk hole 11-4 for accommodating the axial fastener 13, ensuring the compact structure of the rolling element assembly and facilitating the assembly into an omnidirectional wheel.

[0084] The aforementioned support bracket 12 is injection molded from glass fiber reinforced nylon or die-cast from aluminum alloy. Specifically, in this embodiment, when the support bracket 12 is manufactured using injection molding, it is made of glass fiber reinforced nylon, such as using 30% glass fiber reinforced nylon. When the support bracket 12 is manufactured using die casting, it is made of aluminum alloy. Using these injection molding or die casting processes facilitates structural design using finite element analysis, ensuring the structural strength of the support bracket 12. The resulting support bracket 12 has high structural strength, is lightweight, and is simple and convenient to mold, resulting in low manufacturing costs. Furthermore, the support bracket 12 has several subtractive material grooves 12-6 located at the shaft mounting portion 12-1. These grooves not only reduce material usage but also ensure uniform wall thickness of the support bracket 12, reducing injection molding or die casting defects and improving part manufacturing precision. Figure 7 As shown, the rolling element 11 in this embodiment includes an inner core 11a and a tread 11b. The tread 11b covers the inner core 11a. The inner core 11a is injection molded from glass fiber reinforced nylon material, or it can be injection molded from 30% glass fiber reinforced nylon material. The tread 11b is made of elastic and wear-resistant material, such as rubber, TUP, PU and other elastic materials. Several annular grooves 11-2 are also provided on the outer wall of the tread 11b. The annular grooves 11-2 can play a role in anti-slip and material reduction, and can also change the uniformity of the periodic vibration frequency of the gap at the joint of two adjacent rolling elements 11 when rolling in a circle, thereby changing the vibration and noise frequency and improving the comfort of human senses.

[0085] It should be noted that, in order to improve the support performance of the cantilever shaft 14 for the rolling element 11, the cantilever end of the cantilever shaft 14 can also extend beyond the small-diameter end of the rolling element 11. When the rolling element assembly 10 is assembled onto the hub assembly 20 to form an omnidirectional wheel, the cantilever end of the cantilever shaft 14 can rest on the shaft mounting portion 12-1 of the adjacent support bracket 12 to improve the support strength for the rolling element 11 and increase the load-bearing capacity of the omnidirectional wheel. This design, in which the cantilever end of the cantilever shaft 14 is supported on the shaft mounting portion 12-1 of the adjacent support bracket 12, is more suitable for situations where the included angle α between the axes of adjacent rolling elements 11 is small.

[0086] Continue to refer to Figures 10 to 15As shown, the low-cost omnidirectional wheel of this embodiment includes a hub assembly 20 comprising a hub mounting sleeve 21 and flange plates 22 disposed at both ends of the hub mounting sleeve 21. One or both ends of the hub mounting sleeve 21 are fitted with the corresponding flange plates 22 by means of shaft hole sleeve positioning. The outer periphery of the flange plates 22 is fixedly connected to the bearing bracket 12 of the corresponding rolling element assembly 10 by means of a first fastener 23. When one flange plate 22 is fitted with the hub mounting sleeve 21 by means of shaft hole sleeve positioning, the other flange plate 22 can be fixed together with the hub mounting sleeve 21 by means of welding, riveting, bolting, etc. In this embodiment, the preferred solution is to fit the two flange plates 22 with the shaft holes of the hub mounting sleeve 21 respectively, which allows the flange plates 22 and the hub mounting sleeve 21 to be manufactured separately, reducing the manufacturing difficulty of the hub assembly 20. During installation, the support brackets 12 of each rolling element assembly 10 can be first fixed to the flange plate 22 on one side using the first fastener 23. Then, the hub mounting sleeve 21 and the flange plate 22 on the other side are installed, and the flange plate 22 on the other side is fixedly connected to the support brackets 12 of each rolling element assembly 10 using the first fastener 23. The flange plate 22 is used to assemble each rolling element assembly 10, and the hub mounting sleeve 21 is used to axially position and support the flange plate 22. The hub mounting sleeve 21, the flange plates 22 at both ends, and each group of rolling element assemblies 10 can be assembled together simply and quickly to form an omnidirectional wheel structure. The assembly process is simple and convenient, which can effectively reduce the manufacturing cost of the omnidirectional wheel.

[0087] like Figure 11 and Figure 12As shown, in this embodiment, after the center of the flange plate 22 is axially positioned on the hub mounting sleeve 21, there is a gap ΔH between the outer periphery of the flange plate 22 and the contact surface of the bearing bracket 12, so that the center of the flange plate 22, after being locked to the bearing bracket 12 by the first fastener 23, arches slightly outward. Thus, after the first fastener 23 is tightened, the outer periphery of the flange plate 22 deforms slightly inward, forming an arched structure in the center of the flange plate 22. This not only ensures a firm and reliable lock, guaranteeing a stable and secure connection between the flange plate 22 and the hub mounting sleeve 21, but also improves the pressure resistance of the flange plate 22 and enhances the overall load-bearing capacity of the omnidirectional wheel. In this embodiment, the flange plate 22 can be a flat plate structure. When the flange plate 22 is a flat plate structure, the aforementioned arched structure of the flange plate 22 can be designed as follows: the distance H1 between the two ends of the hub mounting sleeve 21 and the axial positioning surface of the middle part of the flange plate 22 is 2×ΔH larger than the distance H2 between the two sides of the bearing bracket 12 and the positioning contact surface of the outer periphery of the flange plate 22. After being locked with the bearing bracket 12 by the first fastener 23, the middle part of the flange plate 22 arches slightly outward, thus ensuring that each side arches by approximately ΔH. That is, the axial positioning surface of the hub mounting sleeve 21 relative to the middle part of the flange plate 22 protrudes outward by approximately ΔH compared to the contact surface between the outer periphery of the flange plate 22 and the bearing bracket 12 on the same side, so that the middle part of the flange plate 22 arches slightly outward after being locked with the bearing bracket 12 by the first fastener 23, ensuring a stable and reliable connection between the flange plate 22 and the hub mounting sleeve 21. In this embodiment, ΔH = 0.1~0.5mm, preferably 0.2mm.

[0088] Further reference Figures 12 to 15As shown, the end of the aforementioned hub mounting sleeve 21 is provided with a positioning ring platform 21-1. The inner side of the positioning ring platform 21-1 has a ring platform positioning surface 21-1a. The center of the flange plate 22 has a center hole 22-2 that fits with the positioning ring platform 21-1 with a clearance. The center hole 22-2 of the flange plate 22 is fitted onto the corresponding side of the positioning ring platform 21-1, and the center of the flange plate 22 is axially positioned by the ring platform positioning surface 21-1a. The ring platform positioning surface 21-1a is the aforementioned axial positioning surface for the center of the flange plate 22. With this shaft hole fit structure, the assembly structure of the hub mounting sleeve 21 and the flange plate 22 is simple and easy to process and manufacture. The support bracket 12 also has a connecting portion 12-2 for connecting with the flange plate 22. The outer periphery of the flange plate 22 has several connecting arms 22-1 distributed radially in a circular pattern. The connecting portion 12-2 of the support bracket 12 has positioning grooves 12-3 on both sides that mate with the connecting arms 22-1. The inner side of the positioning groove 12-3 has an abutment surface 12-3a that contacts the connecting arm 22-1. The abutment surface 12-3a of the positioning groove 12-3 has a connecting hole 12-4. The connecting arm 22-1 has a corresponding through hole 22-1a. The first fastener 23 passes through the through hole 22-1a and is screwed into the corresponding connecting hole 12-4 to connect the connecting arm 22-1 to the support bracket 12. The design of the connecting arm 22-1 facilitates positioning and assembly with the corresponding support bracket 12, and the connecting arm 22-1 makes it easier for the flange plate 22 to undergo slight arching deformation, resulting in a firm and stable connection between the flange plate 22 and the rolling element assembly 10. The connecting arm 22-1 can be accommodated within the positioning groove 12-3, facilitating the transfer of force from the rolling element assembly 10 to the flange plate 22 and reducing the shearing effect on the first fastener 23. The first fastener 23 is a self-tapping screw, which passes through the through hole 22-1a and is screwed into the corresponding connecting hole 12-4 to connect the connecting arm 22-1 to the support bracket 12. Using self-tapping screws simplifies the connection process, reduces processing and manufacturing costs, and simplifies the connection operation. The aforementioned abutment surface 12-3a serves as the positioning contact surface between the support bracket 12 and the outer periphery of the flange plate 22 on both sides. Each support bracket 12 is fixedly connected to its corresponding connecting arm 22-1 on the same side of the flange plate 22 using two self-tapping screws, ensuring a strong and reliable connection. For ease of space arrangement, the self-tapping screws can be designed with one large and one small screw to guarantee connection strength. The aforementioned hub mounting sleeve 21 and flange plate 22 can be made of stainless steel or ordinary carbon steel.

[0089] Depending on the application, an omnidirectional wheel can be used as either a driven wheel or a drive wheel. When used as a driven wheel, such as... Figure 14 and Figure 15 As shown, the hub mounting sleeve 21 is a bearing sleeve, and a pair of bearings 24 are installed inside the hub mounting sleeve 21. The two bearings 24 are positioned by a spacer 25. When the omnidirectional wheel is used as a drive wheel, as... Figure 16 and Figure 17As shown, the center of the hub mounting sleeve 21 has a drive shaft hole 21-2. A keyway or internal spline or other transmission structure can be set in the drive shaft hole 21-2 to realize the connection with the power mechanism. The hub mounting sleeve 21 is connected to the flange plate 22 at the corresponding end by a second fastener 26. The second fastener 26 can be a bolt. A threaded hole is provided on the annular positioning surface 21-1a of the hub mounting sleeve 21. The second fastener 26 is screwed into the threaded hole to fix the middle part of the flange plate 22 to the hub mounting sleeve 21, ensuring stable torque transmission.

[0090] This embodiment also relates to a mobility tool using the aforementioned omnidirectional wheels, which include the low-cost omnidirectional wheels described above. The mobility tool can be an electric wheelchair, a small vehicle, a transport trolley, or a walking robot, etc. Generally, omnidirectional wheels can serve as steering wheels for the mobility tool, making it more agile and reducing its turning radius. Taking an electric wheelchair as an example, when the rear wheels of the electric wheelchair are the drive wheels, the front wheels (steering wheels) can use the aforementioned low-cost omnidirectional wheels; when the front wheels of the electric wheelchair are the drive wheels, the rear wheels can use the aforementioned low-cost omnidirectional wheels. Mobility tools using the aforementioned omnidirectional wheels offer flexible and convenient steering, further reducing the cost of the mobility tool and significantly improving its market competitiveness.

[0091] This invention discloses a low-cost omnidirectional wheel and a mobile tool using the same wheel. Through optimized design of the rolling element ratio coefficient, it balances the number and size of the rolling elements while maintaining a moderate overall thickness. This reduces the number of rolling elements, lowers manufacturing costs, and decreases repetitive assembly steps, improving assembly efficiency. Furthermore, compared to existing omnidirectional wheels, the larger maximum diameter of the rolling elements enhances obstacle-crossing capability during lateral rolling, while also maintaining load-bearing capacity. In addition, optimized design of the rolling element assembly and hub assembly structure, materials, and manufacturing and assembly processes simplifies the manufacturing and assembly process, further reducing manufacturing costs and complexity, and significantly enhancing the market competitiveness of the omnidirectional wheel and the mobile tool using it.

[0092] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A low-cost omnidirectional wheel, comprising: A rolling element assembly (10) includes a rolling element (11) and a support bracket (12), wherein the rolling element (11) is rotatably mounted on one side of the support bracket (12); A hub assembly (20) has several rolling element assemblies (10) arranged circumferentially on its outer periphery. The support brackets (12) of each rolling element assembly (10) are mounted on the hub assembly (20). The rolling elements (11) of adjacent rolling element assemblies (10) are connected end to end, so that the outer contour generatrix of each rolling element (11) is... m All are located within the same envelope circle O superior; Its features are: The rolling element ratio coefficient of this low-cost omnidirectional wheel is 0.035~0.

06. The rolling element ratio coefficient is the ratio of the number of rolling elements (11) in the omnidirectional wheel to the number of the envelope circle. O The ratio of the diameters of the two circles, where the enclosing circle is the diameter of the circle. O The diameter is measured in millimeters; the included angle between the axes of adjacent rolling elements (11) α The range is 24° to 40°. The bearing bracket (12) is an injection molded part or a die-cast part. The shaft mounting part (12-1) of the bearing bracket (12) is integrally connected to the cantilever shaft (14) by injection molding or die casting process. The shaft hole part (11-3) of the rolling element (11) is mounted on the cantilever shaft (14) by the cantilever end. The hub assembly (20) includes a hub mounting sleeve (21) and flange plates (22) located at both ends of the hub mounting sleeve (21). One or both ends of the hub mounting sleeve (21) are fitted with the flange plates (22) at the corresponding ends by a shaft hole sleeve for positioning. The outer periphery of the flange plate (22) is fixedly connected to the bearing bracket (12) of the corresponding rolling element assembly (10) by a first fastener (23). The distance between the two ends of the hub mounting sleeve (21) and the axial positioning surface of the middle part of the flange plate (22) H 1 The distance between the positioning contact surfaces of the two sides of the bearing support (12) and the outer periphery of the flange plate (22) is greater than the distance between the two sides of the bearing support (12) and the flange plate (22). H 2 Large 2× ∆H The flange plate (22) is a flat plate structure. After being locked with the bearing bracket (12) by the first fastener (23), the middle of the flange plate (22) arches slightly outward.

2. The low-cost omnidirectional wheel according to claim 1, characterized in that: The envelope circle O When the diameter is 8 inches, the number of rolling elements (11) in the omnidirectional wheel is 9 to 10; The envelope circle O When the diameter is 9 inches, the number of rolling elements (11) in the omnidirectional wheel is 9 to 12; The envelope circle O When the diameter is 10 inches, the number of rolling elements (11) in the omnidirectional wheel is 10 to 13; The envelope circle O When the diameter is 12 inches, the number of rolling elements (11) in the omnidirectional wheel is 11 to 14; The envelope circle O When the diameter is 13 inches, the number of rolling elements (11) in the omnidirectional wheel is 12 to 15.

3. The low-cost omnidirectional wheel according to claim 1 or 2, characterized in that: The adjacent rolling elements (11) are fitted end-to-end with a clearance fit, and the axis of each rolling element (11) is located within the envelope circle. O Within the plane in which it is located; the generatrix of the rolling element (11) m The outer diameter of the rolling element (11) is an arc and gradually increases from one end to the other along the axial direction. The large diameter end of the rolling element (11) has an inwardly recessed receiving groove (11-1). The bearing bracket (12) has a shaft mounting part (12-1) that is accommodated in the receiving groove (11-1) of the rolling element (11). The side of the bearing bracket (12) away from the shaft mounting part (12-1) also has a clearance groove (12-5) for accommodating the small diameter end of the adjacent rolling element (11).

4. The low-cost omnidirectional wheel according to claim 3, characterized in that: The rolling element (11) has a shaft hole (11-3) that is rotatably fitted with the cantilever shaft (14) through a bushing (15). The rolling element (11) and the cantilever shaft (14) are axially limited by an end face wear-resistant washer sleeved on the cantilever shaft (14). The cantilever shaft (14) is also provided with an elastic washer (18) for pressing the end face wear-resistant washer.

5. The low-cost omnidirectional wheel according to claim 4, characterized in that: The bushing (15) and the rolling element (11) are sequentially sleeved on the cantilever shaft (14) from the cantilever end and locked and fixed by the axial fastener (13); the end face wear-resistant washer includes a first wear-resistant washer (16) and a second wear-resistant washer (17), the first wear-resistant washer (16) and the second wear-resistant washer (17) are disposed between the axial fastener (13) and one end face of the shaft hole (11-3), and the elastic washer (18) is disposed between the first wear-resistant washer (16) and the second wear-resistant washer (17).

6. The low-cost omnidirectional wheel according to claim 5, characterized in that: The elastic washer (18) is a wave washer, and the bushing (15) is a powder metallurgy oil-impregnated bushing; the rolling element (11) has a countersunk hole (11-4) on one side near the cantilever end of the cantilever shaft (14) for accommodating the axial fastener (13).

7. The low-cost omnidirectional wheel according to claim 3, characterized in that: The bearing bracket (12) is injection molded from glass fiber reinforced nylon or die-cast from aluminum alloy. It has several material reduction grooves (12-6) at the position of the shaft mounting part (12-1) on the bearing bracket (12).

8. The low-cost omnidirectional wheel according to claim 3, characterized in that: The rolling element (11) includes an inner core (11a) and a tread (11b). The tread (11b) covers the inner core (11a). The inner core (11a) is injection molded from glass fiber reinforced nylon material. The tread (11b) is made of elastic wear-resistant material. Several annular grooves (11-2) are also provided on the outer wall of the tread (11b).

9. The low-cost omnidirectional wheel according to claim 1, characterized in that: The end of the hub mounting sleeve (21) is provided with a positioning ring platform (21-1), the inner side of the positioning ring platform (21-1) has a ring platform positioning surface (21-1a), the middle part of the flange plate (22) has a center hole (22-2) that is clearance-fitted with the positioning ring platform (21-1), the center hole (22-2) of the flange plate (22) is sleeved on the positioning ring platform (21-1) on the corresponding side, and the center part of the flange plate (22) is axially positioned by the ring platform positioning surface (21-1a); The outer periphery of the flange plate (22) has several connecting arms (22-1) arranged radially in a circular pattern. The two sides of the bearing bracket (12) are respectively provided with positioning grooves (12-3) that cooperate with the connecting arms (22-1). The inner side of the positioning groove (12-3) has an abutment surface (12-3a) that positions and contacts the connecting arm (22-1). The abutment surface (12-3a) of the positioning groove (12-3) is provided with a connecting hole (12-4). The connecting arm (22-1) is provided with a corresponding through hole (22-1a). The first fastener (23) passes through the through hole (22-1a) and is screwed into the corresponding connecting hole (12-4) to realize the connection between the connecting arm (22-1) and the bearing bracket (12). The first fastener (23) is a self-tapping screw.

10. The low-cost omnidirectional wheel according to claim 1, characterized in that: When the omnidirectional wheel is used as a driven wheel, a pair of bearings (24) are provided in the hub mounting sleeve (21), and the two bearings (24) are positioned by a spacer (25); When the omnidirectional wheel is used as a drive wheel, the center of the hub mounting sleeve (21) has a drive shaft hole (21-2), and the hub mounting sleeve (21) is connected to the flange plate (22) at the corresponding end by a second fastener (26).

11. A mobile tool, characterized in that: Includes the low-cost omnidirectional wheel as described in any one of claims 1 to 10.

12. The mobile tool according to claim 11, characterized in that: The mobility tool can be an electric wheelchair, a small vehicle, a transport trolley, or a walking robot.

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