CN219446634U - Universal wheel, chassis and mobile device - Google Patents

Abstract

The application relates to a universal wheel, a chassis and a mobile device. The universal wheel comprises a base, a first rotating mechanism, a driving device and a second rotating mechanism; the first rotating mechanism comprises a first rotating shaft and two first idler wheels which are arranged at two ends of the first rotating shaft in a rolling way; one end of the driving device is rotatably connected with the base, and the other end of the driving device is connected with the first rotating shaft so as to drive the first roller to rotate; the second rotating mechanism comprises a second rotating shaft and a second roller wheel which is connected to the second rotating shaft in a rolling way; the second rotating shaft and the first rotating shaft are arranged at intervals in parallel along the advancing direction and are connected through a second connecting mechanism, so that the second roller can rotate under the drive of the first rotating shaft. According to the scheme, the mobile device can smoothly span the gap, when the mobile device enters the elevator car, the universal wheels cannot be clamped in the gap between the car and the ground, and the elevator car can be directly fed in or discharged out, so that the working efficiency of the mobile device is greatly improved.

Description

Universal wheel, chassis and mobile device

Technical Field

The application relates to the technical field of robots, in particular to a universal wheel, a chassis and a mobile device.

Background

In recent years, with the development of economy and the improvement of the living standard of families, the use of robots is gradually increased, and the application is gradually wide. At present, most of the robot chassis uses a form of a driving wheel and universal wheels, particularly a service robot, the universal wheels used on the chassis are gradually increased, and the requirements on the performance and the function of the universal wheels are more and more strict.

The robot has gradually realized unmanned operation at present, especially embodies that it can collaborative work with the elevator, and same robot can realize the work of many floors scene. The universal wheels used on the chassis of the robot are all common single wheels or parallel double wheels at present, and when the gap between the elevator car and the ground is large, the universal wheels are very easy to clamp in the gap and cannot advance or retreat, so that the robot can cause great trouble to the work of floors.

Taking a cleaning robot as an example, when it is required to clean multiple floors, then the robot is required to control the elevator to send it to the designated floor. However, as the front wheel of the chassis of the cleaning robot is a universal wheel and the rear wheel is two driving wheels, the robot needs to fall into when entering the elevator in order to prevent the universal wheel from being clamped in a gap between the elevator car and the ground; and when the robot comes out of the car, the robot needs to turn in the elevator first and then fall out.

However, due to the large shape of the robot body, the robot falls into and out of the elevator car, so that the robot is at risk of touching, bumping and crushing personnel in the car when turning around in the car; and the robot turns around and is time-consuming when getting in and out of the elevator, so that the problem of reducing the working efficiency of the robot exists.

Disclosure of Invention

For solving or partly solving the problem that exists among the relevant technique, this application provides a universal wheel, chassis and mobile device, can make mobile device span across the gap smoothly, for example when mobile device gets into elevator car, the universal wheel can not block in the gap on car and ground, and can go straight out elevator car, improves mobile device's work efficiency greatly.

A first aspect of the present application provides a universal wheel comprising:

a base;

the first rotating mechanism comprises a first rotating shaft and two first idler wheels which are arranged at two ends of the first rotating shaft in a rolling manner;

one end of the driving device is rotatably connected with the base, and the other end of the driving device is connected with the first rotating shaft so as to drive the first roller to rotate;

the second rotating mechanism comprises a second rotating shaft and a second roller wheel which is connected to the second rotating shaft in a rolling way; the second rotating shafts are arranged at intervals in parallel with the first rotating shafts along the advancing direction and are connected through a second connecting mechanism, so that the second idler wheels can rotate under the drive of the first rotating shafts.

As an alternative embodiment, the diameter of the second roller is smaller than the diameter of the first roller.

As an alternative embodiment, the second roller is located behind the first roller in the travelling direction; and/or the second roller is positioned right in the middle of the two first rollers.

As an alternative embodiment, the driving device includes a driving disc rotatably connected to the base, and a first connection mechanism having one end connected to the driving disc and the other end connected to the first rotation shaft.

As an alternative embodiment, the first connection mechanism includes two first connection plates distributed side by side along the axial direction of the first rotating shaft, and two ends of the first connection plates are respectively connected with the driving disc and the first rotating shaft.

As an alternative embodiment, the first connection plate is disposed obliquely downward in the traveling direction.

As an alternative embodiment, the second connecting mechanism comprises a U-shaped connecting plate, the U-shaped connecting plate comprises a first section and two second sections connected with two ends of the first section, and the second rotating shaft is connected between the two second sections; and/or the second section is arranged obliquely upwards along the travelling direction.

As an alternative embodiment, the first connection mechanism further comprises a support plate, the support plate is connected between the two first connection plates, and the support plate is connected with the first section.

As an optional embodiment, the first rotating mechanism further includes two spacer rings, the two spacer rings are respectively disposed at two ends of the first rotating shaft, and two ends of each spacer ring respectively support against two opposite end surfaces of the first roller and the first connecting plate.

As an alternative embodiment, the drive disc includes:

the main shaft is rotatably connected with the base;

the bottom of the rotating disc is connected with the first connecting mechanism, and the rotating disc is sleeved on the main shaft and can rotate under the driving of the main shaft.

As an alternative embodiment:

the inner cavity of the rotating disc comprises a first cavity and a second cavity which are distributed along the axial direction of the main shaft and are communicated, and the first cavity is larger than the second cavity;

the main shaft comprises a first part and a second part which are distributed along the axial direction of the main shaft and are connected, and the diameter of the first part is larger than that of the second part; the top end of the first part is connected with the base, and the bottom end of the first part is connected with the first cavity through a first bearing; the second portion is connected to the second cavity through a second bearing.

A second aspect of the present application provides a chassis comprising:

a tray body; the method comprises the steps of,

the universal wheel is characterized in that the base is arranged at the bottom of the disc body;

the driving wheel is arranged at the bottom of the disc body, and the driving wheel and the universal wheels are distributed at intervals along the advancing direction.

A third aspect of the present application provides a mobile device comprising a chassis as described above.

The technical scheme that this application provided can include following beneficial effect: because the second gyro wheel and two first gyro wheels of this application embodiment go on between the direction of advance staggered arrangement for when second gyro wheel and two first gyro wheels contact with the bottom surface simultaneously, can form stable triangle structure, realize the stable marcing of universal wheel. Simultaneously, also make the universal wheel meet the gap when, second gyro wheel and first gyro wheel can be in turn for providing the support each other for the universal wheel is smooth striden across the gap. And when the universal wheel turns horizontally, the second roller or the first roller can not be transversely clamped in the large gap. Taking mobile device entering elevator car as an example, use the universal wheel of this application embodiment, second gyro wheel and first gyro wheel can not block in the gap of car and ground, and can directly advance and directly go out elevator car, improves mobile device's work efficiency greatly.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The foregoing and other objects, features and advantages of the application will be apparent from the following more particular descriptions of exemplary embodiments of the application as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the application.

FIG. 1 is a perspective view of a universal wheel shown in an embodiment of the present application;

FIG. 2 is an exploded view of a universal wheel shown in an embodiment of the present application;

FIG. 3 is a front view of FIG. 1;

FIG. 4 is a left side view of FIG. 1;

FIG. 5 is a top view of FIG. 1;

FIG. 6 is a schematic view of a caster shown in an embodiment of the present application crossing a gap;

fig. 7 is a full cross-sectional view of a universal wheel shown in an embodiment of the present application.

Reference numerals:

1. a base;

2. a drive plate; 20. a main shaft; 200. a first portion; 201. a second portion; 21. a rotating disc; 210. a first cavity; 211. a second cavity; 22. a first bearing; 23. a second bearing;

3. a first rotation mechanism; 30. a first rotating shaft; 31. a first roller; 32. a spacer ring;

4. a first connection mechanism; 40. a first connection plate; 41. a support plate;

5. a second rotation mechanism; 50. a second rotating shaft; 51. a second roller;

6. a second connection mechanism; 60. a U-shaped connecting plate; 600. a first section; 601. a second section;

7. a driving device.

Detailed Description

Embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It should be understood that although the terms "first," "second," "third," etc. may be used herein to describe various information, these information should not be limited by these terms. These terms are only used to distinguish one type of information from another. For example, a first message may also be referred to as a second message, and similarly, a second message may also be referred to as a first message, without departing from the scope of the present application. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present application, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Unless specifically stated or limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly and may be, for example, fixedly connected or detachably connected or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

The robot has gradually realized unmanned operation at present, especially embodies that it can collaborative work with the elevator, and same robot can realize the work of many floors scene. The universal wheels used on the chassis of the robot are all common single wheels or parallel double wheels at present, and when the gap between the elevator car and the ground is large, the universal wheels are very easy to clamp in the gap and cannot advance or retreat, so that the robot can cause great trouble to the work of floors. Taking a cleaning robot as an example, when it is required to clean multiple floors, then the robot is required to control the elevator to send it to the designated floor. However, as the front wheel of the chassis of the cleaning robot is a universal wheel and the rear wheel is two driving wheels, the robot needs to fall into when entering the elevator in order to prevent the universal wheel from being clamped in a gap between the elevator car and the ground; and when the robot comes out of the car, the robot needs to turn in the elevator first and then fall out. However, due to the large shape of the robot body, the robot falls into and out of the elevator car, so that the robot is at risk of touching, bumping and crushing personnel in the car when turning around in the car; and the robot turns around and is time-consuming when getting in and out of the elevator, so that the problem of reducing the working efficiency of the robot exists.

To above-mentioned problem, this application embodiment provides a universal wheel, can make mobile device span across the gap smoothly, for example when mobile device gets into elevator car, the universal wheel can not block in the gap on car and ground, and can go straight into and go out elevator car, improves mobile device's work efficiency greatly. The following describes the technical scheme of the embodiments of the present application in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a universal wheel shown in an embodiment of the present application; FIG. 2 is an exploded view of a universal wheel shown in an embodiment of the present application; FIG. 3 is a front view of FIG. 1; FIG. 4 is a left side view of FIG. 1; fig. 5 is a top view of fig. 1.

Referring to fig. 1 to 5, the universal wheel of the embodiment of the present application includes a base 1, a driving device 7, a first rotating mechanism 3, and a second rotating mechanism 5. The base 1 is fixed on a chassis of the robot, the driving device 7 is rotatably connected with the base 1, and the driving device 7 can rotate under the control of the moving device. The first rotating mechanism 3 comprises a first rotating shaft 30 and two first rollers 31 which are arranged at two ends of the first rotating shaft 30 in a rolling way, and the driving device 7 is connected with the first rotating shaft 30 through the first connecting mechanism 4 so as to drive the first rollers 31 to rotate. The driving device 7 rotates to drive the first rotating shaft 30 to rotate, and the rotation of the first rotating shaft 30 drives the two first rollers 31 to rotate on the horizontal plane, so that the effects of steering and linear travelling of the first rollers 31 are realized by combining the rolling of the first rollers 31. The second rotating mechanism 5 comprises a second rotating shaft 50 and a second roller 51 which is connected to the second rotating shaft 50 in a rolling way; the second rotating shaft 50 and the first rotating shaft 30 are arranged at intervals in parallel along the travelling direction, that is, the second rollers 51 and the first rollers 31 are staggered along the travelling direction, for example, the second rollers 51 are in front of or behind the first rollers 31. Wherein the direction of travel is horizontally perpendicular to the axis of the first shaft 30. The second rotating shaft 50 is connected with the first rotating shaft 30 through the second connecting mechanism 6, so that the second roller 51 can rotate under the drive of the first rotating shaft 30, the second roller 51 can rotate on a horizontal plane along with the first roller 31, and the second roller 51 can roll by itself, so that the effects of steering and linear running of the second roller 51 are achieved.

The working principle of the universal wheel of the embodiment of the application is as follows:

referring to fig. 6, when a large gap is encountered during traveling of the universal wheel of the embodiment of the present application, since the second roller 51 of the embodiment of the present application is staggered with the two first rollers 31 in the traveling direction, for example, the second roller 51 is behind the first rollers 31. Then the front two first rollers 31 are above the gap and in a suspended state, the rear first rollers 31 still contact the ground and play a main supporting role, so that the first rollers 31 are not trapped in the gap. The rear second roller 51 may then continue to advance so that the front two first rollers 31 span the gap; then when the rear second roller 51 is above the gap and in a suspended state, the front two first rollers 31 have already crossed the gap and are in contact with the ground, which plays a major supporting role. The last two first rollers 31 may continue to advance such that the second roller 51 spans the gap. And finally, the task of crossing the gap by the whole machine is completed.

Because the second rollers 51 and the two first rollers 31 are staggered in the travelling direction, when the second rollers 51 and the two first rollers 31 are contacted with the bottom surface at the same time, a stable triangle structure can be formed, and stable travelling of the universal wheel is realized. At the same time, when the universal wheel meets the gap, the second roller 51 and the first roller 31 can alternately provide support for each other, so that the universal wheel can smoothly cross the gap. And the second roller 51 or the first roller 31 will not be blocked in the large gap laterally when the universal wheel turns horizontally. Taking the case that the moving device enters the elevator car, the universal wheel of the embodiment of the application is used, the second roller 51 and the first roller 31 can not be clamped in a gap between the car and the ground, and the moving device can directly enter and directly exit the elevator car, so that the working efficiency of the moving device is greatly improved.

As an alternative embodiment, the diameter of the second roller 51 is smaller than the diameter of the first roller 31, as shown in fig. 1 and 2.

The universal wheel of this application embodiment is through combining two major diameter first gyro wheels 31 and a minor diameter second gyro wheel 51 for major support effect is played to major diameter first gyro wheel 31, and minor diameter second gyro wheel 51 plays auxiliary support effect. Such a small diameter of the second roller 51 occupies less chassis space and makes the overall caster more compact. And the second roller 51 with small diameter has small eccentricity and small rotation radius, so that the service life of the universal wheel can be prolonged.

As an alternative embodiment, the second roller 51 is located behind the first roller 31 in the traveling direction, as shown in fig. 6 and 7.

Since the first roller 31 is provided in two, the second roller 51 is provided in one. The first roller 31 is primarily forward power during the forward travel of the mobile device. In order to maintain a smooth running of the universal wheel, two first rollers 31 may be provided in front of the second roller 51.

Further, referring to fig. 3, the second roller 51 is located at the middle of the two first rollers 31.

The second roller 51 and the two first rollers 31 form a triangle structure, and when the second roller 51 is located at the middle of the two first rollers 31, the triangle structure is most stable, so that the working efficiency of the whole universal wheel can be improved.

As an alternative embodiment, see fig. 2, the driving device 7 comprises a driving disc 2 and a first connection mechanism 4, the driving disc 2 being rotatably connected to the base 1, one end of the first connection mechanism 4 being connected to the driving disc 2 and the other end being connected to a first rotation shaft 30.

In the embodiment of the application, the driving disc 2 rotates to serve as a main driving force, and the first connecting mechanism 4 is connected with the first rotating shaft 30 to transmit the rotation motion of the driving disc 2 to the first rotating shaft 30, so that the first rotating shaft 30 performs rotation motion, and the steering of the first roller 31 is realized.

As a preferred embodiment, referring to fig. 2, the first connecting mechanism 4 includes two first connecting plates 40 arranged side by side in the axial direction of the first shaft 30, both ends of the first connecting plates 40 being connected to the drive disk 2 and the first shaft 30, respectively.

The top ends of the two first connecting plates 40 are uniformly spaced along the circumferential direction of the driving disc 2, the bottom ends of the two first connecting plates are provided with first mounting holes, and the first rotating shaft 30 can be, for example, a pin shaft penetrating through the two first mounting holes and fixedly connected with the first connecting plates 40. And both ends of the first rotating shaft 30 are locked by locking nuts. Thus, when the driving disc 2 rotates on the horizontal plane, the two first connecting plates 40 can be driven to synchronously rotate, so that the first rotating shaft 30 is driven to rotate on the horizontal plane, and the steering of the universal wheels is realized.

As a preferred embodiment, referring to fig. 4, the first connection plate 40 is disposed obliquely downward in the traveling direction.

The driving disc 2 of the embodiment of the present application is not in the same vertical plane as the first rotating shaft 30, and the driving disc 2 is located behind the first rotating shaft 30 in the traveling direction, so the driving disc 2 needs to be connected with the first rotating shaft 30 through the first connecting plate 40 disposed obliquely downward. Then a longer first connecting plate 40 is required, the longer first connecting plate 40 is equivalent to a long arm, and the first rotating shaft 30 is driven to rotate more effectively.

As a preferred embodiment, referring to fig. 2 and 7, the second connection mechanism 6 includes a U-shaped connection plate 60, and the U-shaped connection plate 60 includes a first section 600, and two second sections 601 connected to both ends of the first section 600, with the second rotation shaft 50 connected between the two second sections 601. Preferably, the second section 601 is disposed obliquely upward in the direction of travel.

The second coupling mechanism 6 of this application embodiment is connected with the second pivot 50 through two second sections 601, and specifically, the bottom of two second sections 601 all is equipped with the second mounting hole, and second gyro wheel 51 is located between two second sections 601, and in second pivot 50 can be that the one end of round pin axle wears to locate two second mounting holes and second gyro wheel 51, the other end passes through lock nut locking, realizes being connected with two second sections 601 and second gyro wheel 51. To achieve synchronous rotation of the two second sections 601, the two second sections 601 are connected into a whole through the first section 600. This results in a U-shaped connection plate 60 formed by the first section 600 and the two second sections 601. Finally, in order to arrange the first and second rotating shafts 30 and 50 back and forth in the traveling direction, this may be achieved by disposing the second segment 601 obliquely upward.

As a preferred embodiment, referring to fig. 2, the first connection mechanism 4 further comprises a support plate 41, the support plate 41 being connected between the two first connection plates 40, and the support plate 41 being connected with the first section 600.

The present embodiment connects the first connecting mechanism 4 with the second connecting mechanism 6 through the support plate 41, and finally connects with the driving disk 2 to form an integral structure. Thus, the universal wheel can be conveniently assembled and transported.

As an alternative embodiment, referring to fig. 2, the first rotating mechanism 3 further includes two spacer rings 32, the two spacer rings 32 are separately disposed at two ends of the first rotating shaft 30, and two ends of each spacer ring 32 respectively abut against two opposite end surfaces of the first roller 31 and the first connecting plate 40.

Since the first roller 31 can roll around the circumference of the first rotating shaft 30, the first roller 31 may move along the axial direction of the first rotating shaft 30 during the rolling process, and in order to prevent the first connecting plate 40 from interfering with the rolling of the first roller 31, the embodiment of the present application is realized by blocking the spacer ring 32 between the first connecting plate 40 and the first roller 31.

As an alternative embodiment, referring to fig. 2, the driving disk 2 includes a main shaft 20 and a rotating disk 21, the main shaft 20 being rotatably connected to the base 1; the bottom of the rotating disc 21 is connected with the first connecting mechanism 4, and the rotating disc 21 is sleeved on the main shaft 20 and can rotate under the drive of the main shaft 20.

The spindle 20 of the embodiment of the present application may be connected to a control part of the moving device, and the rotation of the spindle 20 is controlled by the control part, thereby driving the rotation of the rotating disc 21.

As a preferred embodiment, referring to fig. 7, the inner cavity of the rotating disc 21 includes a first cavity 210 and a second cavity 211 which are distributed and communicated along the axial direction of the main shaft 20, the first cavity 210 being larger than the second cavity 211; the main shaft 20 includes a first portion 200 and a second portion 201 which are distributed and connected in the axial direction of the main shaft 20, the diameter of the first portion 200 being larger than that of the second portion 201; and the top end of the first part 200 is connected with the base 1, and the bottom end is connected with the first cavity 210 through the first bearing 22; the second portion 201 is connected to the second cavity 211 by a second bearing 23.

Since the first rotating mechanism 3 and the second rotating mechanism 5 of the universal wheel have a certain weight, the driving disc 2 needs to have a certain weight to stably drive the first roller 31 and the second roller 51 to rotate. Thus, in the embodiment of the present application, the spindle 20 is designed in two parts, the first part 200 has a large diameter, which can provide the required weight, and the second part 201 has a small diameter, which can realize efficient rotation. And the inner cavity of the rotating disc 21 is also designed as two cavities adapted to the structure of the spindle 20. The first bearing 22 of the embodiment of the present application may be a thrust ball bearing, mainly bearing axial load; the second bearing 23 may be a deep groove ball bearing, carrying both axial and radial loads. The thrust ball bearing and the deep groove ball bearing are matched for use, so that the driving efficiency of the driving disc 2 can be greatly improved.

Corresponding to the embodiment of the application function realizing device, the application also provides a chassis, a mobile device and corresponding embodiments.

The chassis of the embodiment of the application comprises a chassis body, a driving wheel and the universal wheels, wherein the base 1 is arranged at the bottom of the chassis body; the driving wheel is arranged at the bottom of the disc body, and the driving wheel and the universal wheels are distributed at intervals along the advancing direction.

When the chassis of the embodiment of the application moves, the driving wheel provides main advancing power, and the universal wheel provides main supporting effect and steering effect. The driving wheel is matched with the universal wheel, so that the moving efficiency of the chassis is greatly improved.

The mobile device of the embodiment of the application comprises the chassis.

As an alternative embodiment, the mobile device may be a logistics distribution vehicle, patrol vehicle, sewage treatment vehicle, sanitation vehicle, dust collection vehicle, floor cleaning vehicle, watering vehicle, floor sweeping robot, meal delivery robot, shopping guide robot, welcome robot, disinfection robot mower, golf cart, etc.

The universal wheel of this application embodiment can be applicable to robot and unmanned vehicle, can effectually solve robot or unmanned vehicle business turn over elevator to and the crossing ability when having the place of big gap.

The aspects of the present application have been described in detail hereinabove with reference to the accompanying drawings. In the foregoing embodiments, the descriptions of the embodiments are focused on, and for those portions of one embodiment that are not described in detail, reference may be made to the related descriptions of other embodiments. Those skilled in the art will also appreciate that the acts and modules referred to in the specification are not necessarily required in the present application. In addition, it can be understood that the steps in the method of the embodiment of the present application may be sequentially adjusted, combined and pruned according to actual needs, and the modules in the apparatus of the embodiment of the present application may be combined, divided and pruned according to actual needs.

The embodiments of the present application have been described above, the foregoing description is exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the improvement of technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (13)

1. A universal wheel, comprising:

a base (1);

the first rotating mechanism (3), the first rotating mechanism (3) comprises a first rotating shaft (30) and two first rollers (31) which are arranged at two ends of the first rotating shaft (30) in a rolling way;

the driving device (7), one end of the driving device (7) is rotatably connected with the base (1), and the other end of the driving device is connected with the first rotating shaft (30) so as to drive the first roller (31) to rotate;

a second rotating mechanism (5), wherein the second rotating mechanism (5) comprises a second rotating shaft (50) and a second roller (51) which is connected to the second rotating shaft (50) in a rolling way; the second rotating shafts (50) and the first rotating shafts (30) are arranged at intervals in parallel along the advancing direction and are connected through the second connecting mechanism (6), so that the second rollers (51) can rotate under the drive of the first rotating shafts (30).

2. Universal wheel according to claim 1, characterized in that the diameter of the second roller (51) is smaller than the diameter of the first roller (31).

3. Universal wheel according to claim 1, characterized in that the second roller (51) is located behind the first roller (31) in the travelling direction; and/or the second roller (51) is positioned in the middle of the two first rollers (31).

4. Universal wheel according to claim 1, characterized in that the drive means (7) comprise a drive disc (2) and a first connection mechanism (4), the drive disc (2) being rotatably connected to the base (1), one end of the first connection mechanism (4) being connected to the drive disc (2) and the other end being connected to the first swivel (30).

5. Universal wheel according to claim 4, characterized in that the first connection means (4) comprise two first connection plates (40) distributed side by side in the axial direction of the first rotation shaft (30), both ends of the first connection plates (40) being connected with the driving disc (2) and the first rotation shaft (30), respectively.

6. Universal wheel according to claim 5, characterized in that the first connection plate (40) is arranged obliquely downwards in the travel direction.

7. Universal wheel according to claim 5, characterized in that the second connection means (6) comprise a U-shaped connection plate (60), the U-shaped connection plate (60) comprising a first section (600) and two second sections (601) connected to both ends of the first section (600), the second rotation shaft (50) being connected between two second sections (601); and/or the second section (601) is arranged obliquely upwards along the travelling direction.

8. Universal wheel according to claim 7, characterized in that the first connection means (4) further comprise a support plate (41), the support plate (41) being connected between two of the first connection plates (40), and the support plate (41) being connected with the first segment (600).

9. The universal wheel according to claim 5, wherein the first rotating mechanism (3) further comprises two spacer rings (32), the two spacer rings (32) are respectively arranged at two ends of the first rotating shaft (30), and two ends of each spacer ring (32) are respectively abutted against two opposite end surfaces of the first roller (31) and the first connecting plate (40).

10. Universal wheel according to claim 4, characterized in that the drive disc (2) comprises:

the main shaft (20) is rotatably connected with the base (1);

the rotating disc (21), the bottom of rotating disc (21) is connected with first coupling mechanism (4), just rotating disc (21) cover is located on main shaft (20), and can rotate under the drive of main shaft (20).

11. The universal wheel according to claim 10, wherein:

the inner cavity of the rotating disc (21) comprises a first cavity (210) and a second cavity (211) which are distributed and communicated along the axial direction of the main shaft (20), and the first cavity (210) is larger than the second cavity (211);

the main shaft (20) comprises a first part (200) and a second part (201) which are distributed and connected along the axial direction of the main shaft (20), wherein the diameter of the first part (200) is larger than that of the second part (201); the top end of the first part (200) is connected with the base (1), and the bottom end of the first part is connected with the first cavity (210) through a first bearing (22); the second portion (201) is connected to the second cavity (211) by means of a second bearing (23).

12. A chassis, comprising:

a tray body; the method comprises the steps of,

the castor according to any of the claims 1-11, the base (1) being provided at the bottom of the disc body;

the driving wheel is arranged at the bottom of the disc body, and the driving wheel and the universal wheels are distributed at intervals along the advancing direction.

13. A mobile device comprising the chassis of claim 12.