Two-wheel drive module and wheeled transport robot

Abstract

The present application provides a two-wheel drive module and a wheeled transport robot, relating to the technical field of transport robots, including a guiding ring and a walking and steering mechanism. The walking and steering mechanism includes a support frame and two sets of integrated precision drive units. The support frame cooperates with the guiding ring. The support frame and the guiding ring are swingably cooperated around a preset axis, and the two are rotatably cooperated around a center line. Each integrated precision drive unit includes a frameless motor and a cycloidal planetary precision speed reducer. The frameless motor and the cycloidal planetary precision speed reducer share a housing and an input crankshaft. The housing is connected to the support frame, and wheels are arranged on the cycloidal planetary precision speed reducer. This drive module has the advantages of compact structure, large driving force, flexible steering and easy realization of omnidirectional driving, improving the technical problems of steering jamming or overload alarm caused by inaccurate differential execution in the existing solutions, and is particularly suitable for the drive solution of mobile robots for latent driving.

Description

Technical Field

[0001] The present invention relates to the technical field of transportation robots, and more particularly, to a two-wheel drive module and a wheeled transportation robot. Background Art

[0002] Modern intelligent factories, logistics transportation, and handling equipment require wheeled transportation robots to be small in size, strong in handling ability, and have functions such as in-situ steering and omnidirectional driving. The driving methods of wheeled transportation robots include single-wheel drive, differential drive, two-wheel drive, and multi-wheel drive, etc. In the existing driving methods, at least one driving wheel and several steering wheels or driven wheels are required to cooperate to realize the driving of the transportation robot. Among them, a driving unit composed of two independent driving wheels can realize in-situ steering through differential control, and a transportation robot driven by multiple two-wheel driving units can very conveniently realize the function of omnidirectional driving and has strong driving ability.

[0003] Patent 201910361572.5, a transport vehicle and a drive module for a transport vehicle, proposes a two-wheel drive unit in which two drive wheels independently driven by motors are arranged in the inner ring space of a slewing bearing. Patent CN210027667U, a transport vehicle and a drive module for a transport vehicle, proposes a structure in which two motors independently drive the drive wheels, and also uses a slewing bearing for steering, but the slewing bearing is arranged inside the receiving hole. The above two patents aim to solve the problem of instability during the load movement of the transport vehicle, thereby improving the stability of the transport vehicle. However, there are still some other problems in the implementation process:

[0004] 1) Using a slewing bearing with a complete inner and outer ring structure as the drive unit structure of the integrated solution is complex and large in size; 2) The existing direct connection scheme of the motor and the reducer device has an insufficiently compact structure, and the volume of the motor in the drive unit accounts for too large a proportion; 3) Due to the small single-stage speed ratio and low transmission accuracy of the reduction device in the scheme, the output torque of the existing drive unit is small, and the differential control error of the two wheels is too large. During steering, it is easy to cause jamming due to driving constraints, and even trigger an overload alarm. Summary of the Invention

[0005] The purpose of the present invention is to provide a two-wheel drive module and a wheeled transportation robot to meet the requirements of small size, large handling ability, convenient in-situ steering, and omnidirectional driving of the wheeled transportation robot for its driving device.

[0006] The embodiments of the present invention are implemented as follows:

[0007] In a first aspect, the present invention provides a two-wheel drive module, including:

[0008] Guide ring and walking steering mechanism; the guide ring is provided with an installation through-hole, the walking steering mechanism includes a support frame and two sets of integrated precision drive units, the support frame is installed in the installation through-hole, the support frame and the guide ring are swingably matched around a preset axis, and the two are rotatably matched around the center line of the installation through-hole, and the preset axis has an included angle with the center line;

[0009] Each of the integrated precision drive units includes a frameless motor and a cycloid planetary precision reducer. The frameless motor and the cycloid planetary precision reducer share a housing and an input crankshaft. The housing is connected to the support frame, and wheels are provided on the cycloid planetary precision reducer.

[0010] In an alternative embodiment, the two independently controlled sets of integrated precision drive units respectively drive precision gear pairs to drive two wheels; each set of the integrated precision drive units adopts a scheme of integrated precision reducer, motor and angle encoder. The precision drive unit improves the control accuracy of the drive motor through the angle encoder and realizes the precise output rotation angle of the drive unit through the precision reducer; each set of the precision gear pairs includes high-precision straight-tooth cylindrical involute gears, and the high-speed stage gears of the precision gear pairs are composed of two gears with phase offset to form a gear pair meshing clearance elimination mechanism to improve the motion output accuracy of the gear pair.

[0011] In an alternative embodiment, the cycloid planetary precision reducer includes an input end plate, an output end plate, cycloid wheels, a pin tooth assembly, a stud assembly, an input crankshaft, angular contact ball bearings, deep groove ball bearings and cylindrical rollers; the pin tooth assembly and the cycloid wheels form a rolling cycloid pin tooth meshing pair, and the stud assembly and the cycloid wheels, the input end plate and the output end plate form a pin shaft type output mechanism. The input crankshaft axially passes through the cycloid wheels, and at the same time, the input crankshaft and the cycloid wheels are rotationally matched through full complement cylindrical rollers.

[0012] In an alternative embodiment, the pin tooth assembly is composed of circumferentially evenly distributed pin teeth and pin tooth sleeves; the pin tooth assembly and the cycloid wheels form a cycloid pin tooth meshing pair, and the meshing clearance of the meshing pair is controlled by adjusting the roller size of the cycloid pin tooth meshing pair.

[0013] In an alternative embodiment, the stud assembly includes studs and stud sleeves; the left end of the stud is in interference fit with the holes evenly distributed on the output end plate, the right end of the stud is provided with a threaded hole, and the studs respectively pass through the coordinate holes on the cycloid wheels and are connected to the input end plate by screws; the stud sleeves pass through the pin shafts and are located between the pin shafts and the coordinate holes of the cycloid wheels; each of the pin shafts is supported by two independent bushings between the two cycloid wheels, and the clearance between the kinematic pairs of the output mechanism is controlled by adjusting the wall thickness of the bushing.

[0014] In an alternative embodiment, the walking steering mechanism is integrated within the guide ring. A guide raceway is provided on the wall of the mounting through-hole, and a guiding member is provided on the support frame. The guiding member and the guide raceway form a rolling contact pair.

[0015] In an alternative embodiment, the guide raceway is provided as an arc raceway; the guiding member is provided as a spherical member.

[0016] In an alternative embodiment, a limiting member is further provided on the support frame. The limiting member is configured to abut against the guide raceway when the walking steering mechanism swings about the preset axis, so as to limit the swing amplitude of the walking steering mechanism.

[0017] In an alternative embodiment, an angle encoder is installed between the guide ring and the support frame; an angle encoder stator mounting bracket is provided on the upper part of the guide ring to mount the encoder stator; an angle encoder rotor mounting bracket is provided on the support frame structure to mount the encoder rotor.

[0018] In a second aspect, the present invention provides a wheeled transport robot, which includes:

[0019] The two-wheeled drive module according to any one of the foregoing embodiments.

[0020] The beneficial effects of the embodiments of the present invention are:

[0021] In summary, the two-wheeled drive module and the wheeled transport robot provided in this embodiment have at least the following advantages:

[0022] 1. The drive module of the present application has a compact structure and a small volume. Compared with the slewing bearing including a complete inner and outer ring in the prior art, the present application only retains the guide ring with an arc groove raceway, and several spherical guiding media are integrally installed on the support frame, together with the guide ring, forming the guiding structure of the drive module; the driver of the drive module adopts an integrated design scheme of a motor and a precision reducer. Compared with the prior art, the structure is more compact, and the volume of the entire driver is greatly reduced, especially suitable for the drive scheme of a mobile robot with a latent drive.

[0023] 2. The drive module of the present application has a large driving torque. Compared with the prior art, under the same volume, the present application can adopt a motor with a larger power integrated with a reducer; the precision reducer integrated in the present application has a large single-stage speed ratio, a higher unit power density, a larger output torque, and an overload capacity of 4-5 times, which is much higher than the overload capacity of 2-3 times of the planetary reducer in the prior art, and is stable and reliable.

[0024] 3. The drive module of this application has flexible steering, improving problems such as jamming and sticking caused by inaccurate execution of the two wheels during differential control in the prior art. Compared with the prior art, the drive module of this application adopts a precision cycloidal planetary reducer and a precision gear pair with a backlash elimination solution. Each integrated driver is integrated with an angle encoder to improve the control accuracy of the driver, which can greatly improve the execution accuracy of the differential in the drive module, thus improving the technical problems of steering jamming or overload alarm caused by inaccurate differential execution in the prior art; In addition, each drive module is also equipped with an angle encoder for controlling the rotation angle phase of the drive module, which is also suitable for precise steering control when several drive modules drive a wheeled robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0026] Figure 1 Structural schematic diagram of the integrated precision drive unit of Embodiment 1 of the embodiments of the present invention;

[0027] Figure 2 Structural schematic diagram of the two-wheel drive module of Embodiment 1 of the embodiments of the present invention;

[0028] Figure 3 Stereoscopic structural schematic diagram of the two-wheel drive module of Embodiment 2 of the embodiments of the present invention;

[0029] Figure 4 Lateral structural schematic diagram of the two-wheel drive module of Embodiment 2 of the embodiments of the present invention;

[0030] Figure 5 Structural schematic diagram of the guide ring of Embodiment 2 of the embodiments of the present invention;

[0031] Figure 6 Cross-sectional structural schematic diagram of the cylinder body of Embodiment 2 of the embodiments of the present invention;

[0032] Figure 7 Structural schematic diagram of the support frame of Embodiment 2 of the embodiments of the present invention;

[0033] Figure 8 Structural schematic diagram of the walking steering mechanism of Embodiment 2 of the embodiments of the present invention;

[0034] Figure 9 Deformed structural schematic diagram of the walking steering mechanism of Embodiment 2 of the embodiments of the present invention;

[0035] Figure 10 Schematic cross-sectional structure diagram of the driver in Embodiment 2 of the embodiments of the present invention;

[0036] Figure 11 Schematic installation structure diagram of the first angle encoder in Embodiment 2 of the embodiments of the present invention.

[0037] Icon:

[0038] 1 - Pin component; 2 - Angular contact ball bearing; 3 - Housing; 4 - Motor stator; 5 - End cover; 6 - Angle encoder; 7 - Input crankshaft; 8 - Motor rotor; 9 - Input end plate; 11 - Pin bushing; 12 - Cylindrical roller; 13 - Deep groove ball bearing; 14 - Output end plate; 15 - Cycloid gear; 16 - Pin tooth component; 10 - First base; 20 - Second base; 30 - Rotating component; 40 - Driving wheel; 50 - Precision driving unit;

[0039] 001 - Preset axis; 002 - Center line; 100 - Guide ring; 110 - Cylinder; 111 - Mounting through hole; 112 - First end; 113 - Second end; 114 - Guide groove; 1141 - First groove side wall; 1142 - Second groove side wall; 1143 - Groove bottom wall; 120 - Mounting plate;

[0040] 200 - Travel steering mechanism; 210 - Support frame; 211 - Bottom plate; 212 - Top plate; 213 - Front side plate; 214 - Rear side plate; 215 - Left side plate; 216 - Right side plate; 217 - Central axis; 218 - Positioning wheel; 2181 - First positioning wheel; 2182 - Second positioning wheel; 219 - Limiting wheel; 2191 - First limiting wheel; 2192 - Second limiting wheel; 220 - Integrated precision driving unit; 221 - Driver; 2211 - Motor; 2212 - Crankshaft; 2213 - Pin tooth housing; 2214 - Input end plate; 2215 - Pin shaft; 2216 - Bushing; 2217 - Cycloid gear; 22171 - Pin hole; 2218 - Output end plate; 22181 - Output gear; 2219 - Roller; 222 - Wheel; 223 - Driving gear;

[0041] 300 - First angle encoder; 310 - Encoder stator; 320 - Encoder rotor. Detailed implementation manners

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Usually, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0044] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not require further definition and explanation in subsequent drawings.

[0045] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is customarily placed during use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0046] In addition, terms such as "horizontal" and "vertical" do not mean that the components are required to be absolutely horizontal or hanging, but may be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but may be slightly inclined.

[0047] In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the prior art, the structures of wheeled transport robots are diverse. There are two common structures for the drive modules of wheeled transport robots. One is a two-wheel drive structure in which drive wheels independently driven by two motors are arranged in the inner ring space of a slewing bearing. The other is a structure in which a single motor independently drives the drive wheels, and a slewing bearing is also used for steering, but the slewing bearing is arranged inside a receiving hole. The two drive modules in the prior art have the following disadvantages:

[0049] 1. The drive unit structure of the integrated solution using a slewing bearing with a complete inner and outer ring structure is complex and large in size;

[0050] 2. For the existing solution of directly connecting the motor and the reducer device, the structure is not compact enough, and the volume of the motor in the drive unit accounts for too large a proportion;

[0051] 3. The single-stage speed ratio of the reduction device is small, the transmission accuracy is not high, the output torque of the existing drive unit is small, and the differential control error of the two wheels is too large. When steering, it is easy to cause jamming due to drive constraints, and even trigger an overload alarm.

[0052] Embodiment 1

[0053] The embodiment of the present invention discloses an integrated precision drive unit, a drive module for a wheeled robot.

[0054] Please combine Figure 1 - Figure 2 , the integrated precision drive unit 50 disclosed in the embodiment of the present invention adopts a scheme of integrating a precision reducer, a motor and an angle encoder. The reducer adopts a new type of cycloidal planetary precision reducer, which controls the meshing clearance of the meshing pair by adjusting the needle roller size of the cycloidal pin gear meshing pair; each pin shaft of the pin shaft type output mechanism and two cycloidal wheels adopt a structure supported by two independent pin sleeves, so that the clearance between the kinematic pairs of the pin shaft type output mechanism can be controlled by adjusting the wall thickness of the pin sleeve, thereby obtaining the effect of accurate motion output. The angle sensor generally uses an encoder to obtain high-precision motor rotor position information. The new type of cycloidal reducer and the motor are integrally designed, and the rotating shaft of the motor rotor and the input shaft of the reducer are integrally designed; the encoder is installed at the center position on the other side of the motor to monitor the operation of the motor rotor, and is distributed at both ends of the motor with the reducer; the motor stator installation housing and the reducer housing are integrally designed and share a housing.

[0055] The drive module for a wheeled robot disclosed in the embodiment of the present invention mainly includes a first base 10, a second base 20, a rotating member 30, a drive wheel 40 and the above-mentioned integrated precision drive unit 50.

[0056] The first base 10 is the basic frame of the drive module, which can provide an installation basis for the entire drive module. In the embodiment of the present invention, the first base 10 is the frame of the rotatable part in the drive module. It is a box as a whole, and through holes are provided at the center points of the left and right side frame plates. The central shaft passes through the two through holes to complete the fixation, providing an installation position for components such as the drive wheel and the bearing.

[0057] The drive wheel 40 and the integrated precision drive unit 50 are matched and installed with the help of the first base. To save space, the precision drive unit 50 is generally arranged inside the first base 10, and the drive wheel 40 is arranged outside the first base 10 and installed on the central axis. From the inside out, a central axis axial orientation ring, a drive unit driven gear, and a bearing are installed respectively. The drive wheel is installed on the bearing. A drive module for a wheeled robot consists of two drive wheels, and each drive wheel has an independent integrated precision drive unit for driving through gear transmission. The two sets of precision gear pairs of the drive module are composed of high-precision straight-tooth cylindrical involute gears, and the high-speed stage gears of the gear pairs are composed of two gears with a phase shift to form a gear pair meshing clearance elimination mechanism, thereby improving the motion output precision of the gear pair.

[0058] The second base 20 is the outer frame of the drive module, mainly including a cylindrical guide ring and a sensor mounting support. In a wheeled transport robot, the second base 20 is fixedly connected to the bottom of the transport robot. In the embodiment of the present invention, a raceway is left inside the cylindrical guide ring for the use of the rotating mechanism, the sensor support plate provides an installation position for the angle sensor, and an angle encoder stator mounting bracket is provided on the upper part of the guide ring for mounting the encoder stator; an encoder rotor mounting support is provided on the frame structure of the drive module to mount the encoder rotor, so as to facilitate observing the running state of the robot at all times.

[0059] The rotating component 30 enables the drive module to complete flexible steering. In this embodiment, a spherical guiding mechanism is adopted, and a rolling contact pair is formed by a number of spherical guiding components and the inner arc raceway of the cylindrical guide ring. Among them, the drive module is integrated inside the guide ring, and an arc raceway is left inside the guide ring. In this embodiment, four spherical guiding components are adopted. Among them, two large-sized spherical guiding components are installed at the central positions of the front and rear frame plates of the first base 10, and their sizes must match the inner raceway of the guide ring. It is required that these two spherical guiding components can only roll horizontally in the raceway without vertical displacement, so as to fix the relative position of the central axis of the first base 10 and the second base, and ensure the contact between the drive wheel and the ground; the other two spherical guiding components are installed at both ends of the central axis passing through the left and right frame plates of the first base 10, and small-sized spherical guide rings are adopted, and their sizes are smaller than the inner raceway of the guide ring. It is required that they can roll horizontally in the raceway and can also move within a certain limit in the vertical direction, so that the first base 10 can rotate 360° around the vertical direction relative to the second base 20, and can also rotate within a certain angle limit around the central axis of the first base (the axis where the two large-sized spherical guiding components are located). This design improves the degree of freedom of the drive module and helps to improve the adaptability of the transport robot to complex road conditions. For example, when facing an uneven road, this multi-degree-of-freedom design can ensure better contact between the drive wheel and the ground, thereby reducing various impacts on the robot caused by wheel suspension and enhancing the adaptive ability of the system.

[0060] The driving module disclosed in the embodiments of the present invention can play the roles of driving and supporting. To improve the stability of the system, except that the driving wheel 40 of the first base is lower than the lower edge of the second base 20, the rest of the first base is installed inside the second base. Such a design effectively saves space and reduces the overall height of the wheeled transport robot, thereby enhancing the stability of the system. In addition, in this embodiment, an integrated precision driving unit is adopted, which integrates a new type of precision cycloidal planetary reducer and a high-precision angle encoder inside. While ensuring a small volume and high precision, it greatly increases the torque output capacity. In addition, the two sets of precision gear pairs of the driving module are composed of high-precision straight-tooth cylindrical involute gears, and the high-speed stage gears of the gear pairs are composed of two gears with a phase shift to form a gear pair meshing clearance elimination mechanism, which improves the motion output precision of the gear pairs. Compared with the performance of the motor-reducer combination on the current market, the structure of the present invention is more compact, has a smaller volume, a larger output torque, and has a stronger overload capacity and higher output precision.

[0061] For the dual-wheel drive scheme, usually the two driving wheels of the driving module are driven in a differential manner. As described above, there is a raceway inside the guide ring for the spherical guiding component to rotate. When the two driving wheels have a differential speed, the spherical guiding component rolls on the inner wall, and the relative rotation of the first base 10 relative to the second base 20 can be realized. Since the second base 20 is fixed to the transport vehicle frame, in fact, the first base makes a relative rotation relative to the entire wheeled robot body, so that the robot can complete the steering. In addition, because the small-sized spherical guiding component has no fixed track, its "point-to-plane" contact mode with the inner raceway of the second base 20 enables the steering wheel to freely roll in the raceway, so that the first base can swing relative to the second base, forming a relative rotation with the central axis of the first base 10 (the straight line where the two large-sized spherical guiding components are located) as the axis.

[0062] Meanwhile, each integrated precision driving unit includes a frameless motor and a cycloidal planetary precision reducer. The frameless motor and the cycloidal planetary precision reducer share a housing and an input crankshaft. The housing is connected to the support frame, and a wheel is arranged on the cycloidal planetary precision reducer. Two independently controlled integrated precision driving units drive the precision gear pairs respectively to drive the two wheels; each set of integrated precision driving units adopts a scheme of integrating a precision reducer, a motor and an angle encoder. The precision driving unit improves the control precision of the driving motor through the angle encoder and realizes the accurate output rotation angle of the driving unit through the precision reducer; each set of precision gear pairs includes high-precision straight-tooth cylindrical involute gears, and the high-speed stage gears of the precision gear pairs are composed of two gears with a phase shift to form a gear pair meshing clearance elimination mechanism to improve the motion output precision of the gear pairs.

[0063] Please combineFigure 2 , wherein, the housing includes a connected outer shell 3 and an end cover 5. The cycloid planetary precision reducer includes an input end disc 9, an output end disc 14, a cycloid gear 15, a pin tooth assembly 16, a stud assembly 1, an input crankshaft 7, an angular contact ball bearing 2, a deep groove ball bearing 13, a cylindrical roller 12, and an angle encoder 6. The pin tooth assembly 16 and the cycloid gear 15 form a rolling cycloid pin tooth meshing pair, and the stud assembly 1, the cycloid gear 15, and the output end disc 14 form a stud type output mechanism. The input crankshaft 7 axially passes through the cycloid gear 15, and at the same time, the input crankshaft 7 and the cycloid gear 15 are rotationally matched through full complement cylindrical rollers. The pin tooth assembly 16 is composed of circumferentially evenly distributed pin teeth and pin tooth sleeves; the pin tooth assembly 16 and the cycloid gear 15 form a cycloid pin tooth meshing pair, and the meshing clearance of the meshing pair is controlled by adjusting the size of the needle rollers of the cycloid pin tooth meshing pair. The stud assembly 1 includes studs and a stud sleeve 11. The left end of the stud is in interference fit with the holes evenly distributed on the output end disc. The right end of the stud is provided with a threaded hole. The studs respectively pass through the coordinate holes on the cycloid gear and are connected to the input end disc by screws; the stud sleeve passes through the stud and is located between the stud and the coordinate holes of the cycloid gear; each stud is supported by two independent bushings between two cycloid gears, and the clearance between the kinematic pairs of the output mechanism is controlled by adjusting the wall thickness of the stud bushings. The motor includes a mutually cooperating motor stator 4 and a motor rotor 8. The angle encoder 6 includes an encoder stator and an encoder rotor. The encoder stator is fixed on the end cover 5 of the integrated motor reducer drive unit, and the encoder rotor is fixed on the motor rotor and rotates therewith; the closed-loop control of the motor is completed by monitoring and feedback the motor speed information and the motor rotor position information, improving the motor control accuracy and achieving the precise output of the entire mechanism.

[0064] Embodiment 2

[0065] Please refer to Figure 3 - Figure 11 , in view of this, the designer designed a double-wheel drive module, which can simplify the structure, improve the compactness, reduce the volume, and lower the cost.

[0066] Please refer to Figure 3 - Figure 11, in this embodiment, the dual-wheel drive module includes a guiding ring 100 and a walking and steering mechanism 200. The guiding ring 100 is provided with an installation through hole 111. The walking and steering mechanism 200 includes a support frame 210 and two sets of integrated precision drive units 220. The support frame 210 is installed in the installation through hole 111. The support frame 210 and the guiding ring 100 are rotatably matched around a preset axis 001, and the two are rotatably matched around the center line 002 of the installation through hole 111. The preset axis 001 and the center line 002 have a non-zero included angle. Each integrated precision drive unit 220 includes a wheel 222 and a driver 221. The driver 221 is connected to the support frame 210. The wheel 222 is rotatably connected to the support frame 210. The driver 221 is in transmission connection with the corresponding wheel 222 for driving the corresponding wheel 222 to rotate; the wheel axles of the two wheels 222 are coaxially arranged.

[0067] In this embodiment, unless otherwise specified, the preset axis 001 and the center line 002 are vertically arranged, that is, the included angle between the two is 90°. Obviously, in other embodiments, the preset axis 001 and the center line 002 can also be other included angles.

[0068] The working principle of the dual-wheel drive module provided in this embodiment is as follows:

[0069] The two wheels 222 are in contact with the ground. The two drivers 221 independently control the rotation of the two wheels 222 respectively, so as to drive the whole to walk on the ground through the two wheels 222. When steering control is required, the output powers of the two drivers 221 are different, and the rotation speeds of the two wheels 222 are different, thus forming a differential motion, so that the support frame 210 rotates relative to the guiding ring 100 around the center line 002 of the installation through hole 111, and then the steering action is completed. At the same time, during the operation of the drive module, since the whole walking and steering mechanism 200 of the drive module can rotate relative to the guiding ring 100 around the preset axis 001, when the two wheels 222 walk on the uneven ground, the heights of the contact positions of the two wheels 222 with the ground are different. At this time, the support frame 210 can adaptively rotate relative to the guiding ring 100 around the preset axis 001 by a certain angle to balance the height difference, so as to ensure that both wheels 222 can be in contact with the ground, effectively improving the adverse effects caused by the suspension of the wheels 222, enhancing the overall adaptability, and having a wide range of applications.

[0070] In this embodiment, optionally, the guide ring 100 includes a cylindrical body 110 and a mounting plate 120. The cylindrical body 110 is of a cylindrical structure, and both ends of the cylindrical body 110 are open. For the convenience of description, the two ends of the cylindrical body 110 are respectively a first end 112 and a second end 113. The cavity of the cylindrical body 110 is the mounting through hole 111, and the mounting through hole 111 is set as a circular hole. An annular guide groove 114 is provided on the hole wall of the mounting through hole 111, and the guide groove 114 is arranged around the center line 002 of the mounting through hole 111. The cross-sectional shape of the guide groove 114 is U-shaped or other shapes. The guide groove 114 has an annular first groove side wall 1141 and an annular second groove side wall 1142 that are oppositely arranged in the extending direction of the center line 002, and the first groove side wall 1141 and the second groove side wall 1142 are connected by an annular groove bottom wall 1143. The mounting plate 120 is arranged at the first end 112 of the cylindrical body 110 and can be fixed to the cylindrical body 110 by screws or the like. The wheel 222 protrudes from the second end 113. In this way, when the driving module is operating normally, the second end 113 faces the ground and the first end 112 faces away from the ground. Specifically, the mounting plate 120 is a rectangular plate, the mounting plate 120 straddles the first end 112 of the cylindrical body 110, and both ends of the mounting plate 120 are fixed to the end surface where the first end 112 of the cylindrical body 110 is located by screws. In this way, both sides of the mounting plate 120 are limited, and the connection structure between the mounting plate 120 and the cylindrical body 110 is firm.

[0071] In this embodiment, optionally, the support frame 210 includes a bottom plate 211, a top plate 212, a left side plate 215, a right side plate 216, a front side plate 213, and a rear side plate 214, all of which are rectangular. The bottom plate 211 and the top plate 212 are arranged oppositely. The left side plate 215, the front side plate 213, the right side plate 216, and the rear side plate 214 are sequentially connected end to end to form a cylindrical structure, and the bottom plate 211 is simultaneously connected to the bottom side of the cylindrical structure, and the top plate 212 is simultaneously connected to the top side of the cylindrical structure. Meanwhile, a first positioning wheel 2181 is provided at the middle position of the front side plate 213, and a second positioning wheel 2182 is provided at the middle position of the rear side plate 214. The first positioning wheel 2181 and the second positioning wheel 2182 are coaxially arranged, and the axis where the first positioning wheel 2181 and the second positioning wheel 2182 are located is the preset axis 001. Both the first positioning wheel 2181 and the second positioning wheel 2182 are provided with spherical surfaces. For example, both of them can be set as spheres. Both the first positioning wheel 2181 and the second positioning wheel 2182 can be clamped in the guide groove 114, so that the spherical surfaces are simultaneously in contact with the groove bottom wall 1143, the first groove side wall 1141, and the second groove side wall 1142 of the guide groove 114, and can be slidably matched with the guide groove 114 in the extending direction of the guide groove 114. Meanwhile, after the first positioning wheel 2181 and the second positioning wheel 2182 are clamped in the guide groove 114, they are relatively fixed with the guide groove 114 in the extending direction of the center line 002 of the installation through hole 111. In this way, the support frame 210 can rotate relative to the guide ring 100 around the center line 002 and swing relative to the guide ring 100 around the preset axis 001, and the support frame 210 will not move up and down relative to the guide ring 100, which is stable and reliable.

[0072] It should be noted that both the first positioning wheel 2181 and the second positioning wheel 2182 are in point-to-surface contact with the groove wall of the guide groove 114. The contact areas of the first positioning wheel 2181 and the second positioning wheel 2182 with the guide groove 114 are small, the friction force is small, and the movement is more flexible.

[0073] Furthermore, weight-reducing holes can also be provided on the bottom plate 211, the top plate 212, the left side plate 215, the right side plate 216, the front side plate 213, and the rear side plate 214, which can save materials and reduce the weight at the same time.

[0074] Meanwhile, a first positioning hole is provided at the middle position of the left side plate 215, and a second positioning hole is provided at the middle position of the right side plate 216. Both the first positioning hole and the second positioning hole are circular holes and are coaxially arranged. A central shaft 217 passes through the first positioning hole and the second positioning hole simultaneously. A bearing is sleeved outside the central shaft 217, and a driving gear 223 is sleeved outside the bearing. The driving gear 223 is fixedly connected to the wheel 222. In this way, the torque of the driver 221 can be transmitted to the wheel 222 through the driving gear 223, so that the vehicle can move by rotating the wheel 222 relative to the central shaft 217. Further, both ends of the central shaft 217 extend out of the corresponding wheels 222, and a first limiting wheel 2191 and a second limiting wheel 2192 are respectively installed at both ends of the central shaft 217. Both the first limiting wheel 2191 and the second limiting wheel 2192 are provided with spherical surfaces. For example, both of them are set as spheres. Both the first limiting wheel 2191 and the second limiting wheel 2192 are clamped in the guiding groove 114. The first limiting wheel 2191 and the second limiting wheel 2192 can slide along the extending direction of the guiding groove 114. At the same time, there is a distance between the first limiting wheel 2191 and the second limiting wheel 2192 and the first groove side wall 1141 and the second groove side wall 1142. Or rather, when in the normal state, the first limiting wheel 2191 is located at the middle position between the first groove side wall 1141 and the second groove side wall 1142, and the second limiting wheel 2192 is located at the middle position between the first groove side wall 1141 and the second groove side wall 1142. In this way, the support frame 210 can swing relative to the guiding ring 100 around the preset axis 001. And when the support frame 210 swings to a certain angle, the first limiting wheel 2191 contacts the first groove side wall 1141 while the second limiting wheel 2192 contacts the second groove side wall 1142, or the first limiting wheel 2191 contacts the second groove side wall 1142 while the second limiting wheel 2192 contacts the first groove side wall 1141. In these two states, the support frame 210 swings to the limit position, so as to limit the swinging range of the support frame 210 and prevent accidents such as rollover.

[0075] It should be understood that since both the first limiting wheel 2191 and the second limiting wheel 2192 have spherical surfaces, when the spherical surfaces contact the groove walls of the guiding groove 114, it is a point-to-surface contact mode. The contact areas between the first limiting wheel 2191 and the second limiting wheel 2192 and the groove walls of the guiding groove 114 are small, the friction is small, and the movement is more flexible.

[0076] In this embodiment, it should be noted that the first positioning wheel 2181, the second positioning wheel 2182, the first limiting wheel 2191 and the second limiting wheel 2192 can also be other structures that are not spheres. For example, please refer to Figure 7, both the positioning wheel 218 and the limiting wheel 219 are cylindrical wheel bodies. Moreover, the number of the limiting wheels 219 is four, with two limiting wheels 219 as a group, and the two groups of limiting wheels 219 are respectively arranged on the left side plate 215 and the right side plate 216.

[0077] In this embodiment, optionally, the driver 221 is set as a cycloid pinwheel speed reducer.

[0078] Optionally, the cycloid pinwheel speed reducer includes a motor 2211 and a speed reduction transmission mechanism. The speed reduction transmission mechanism includes a crankshaft 2212, a pin gear housing 2213, an input end plate 2214, a pin shaft 2215, a pin sleeve 2216, a cycloid gear 2217, and an output end plate 2218. The housing of the motor 2211 is connected to the pin gear housing 2213. The crankshaft 2212 is connected to the rotor of the motor 2211. The input end plate 2214, the cycloid gear 2217, and the output end plate 2218 are all sleeved outside the crankshaft 2212 and arranged in sequence; rollers 2219 are provided between the cycloid gear 2217 and the pin gear housing 2213 as well as between the cycloid gear 2217 and the pin gear housing 2213; a pin hole 22171 is provided on the cycloid gear 2217. The pin sleeve 2216 is sleeved outside the pin shaft 2215, and the input end plate 2214 and the output end plate 2218 are connected by the pin shaft 2215; the pin sleeve 2216 is inserted into the pin hole 22171; an output gear 22181 is fixedly connected to the output end plate 2218, and the output gear 22181 meshes with the driving gear 223 on the central shaft 217. In this way, the torque output by the output end plate 2218 can be transmitted to the wheel 222, thereby driving the wheel 222 to rotate.

[0079] Furthermore, both the output gear 22181 and the driving gear 223 are set as high-precision straight-tooth cylindrical involute gears, and the phase of the output gear 22181 and the driving gear 223 is offset, so as to eliminate the meshing clearance of the gear pair composed of the output gear 22181 and the driving gear 223 and improve the motion output precision of the gear pair.

[0080] Furthermore, the housing of the motor 2211 and the pin gear housing 2213 are of an integral structure, that is, the rotor and stator of the motor 2211 share a housing with the speed reduction transmission mechanism. The motor 2211 and the speed reduction transmission mechanism adopt a deep integration method. Compared with the structure in which the motor 2211 and the reducer in the prior art are directly connected, the overall structure is more compact, the volume is smaller, and it is more inclined to be miniaturized, especially suitable for the driving scheme of a mobile robot with a latent drive.

[0081] At the same time, since a pin sleeve 2216 is provided outside the pin shaft 2215, the gap between the pin sleeve 2216 and the pin hole 22171 on the cycloid gear 2217 can be adjusted by adjusting the wall thickness of the pin sleeve 2216, which is convenient for flexible adjustment of the output power, has a wide range of uses, and can obtain an accurate motion output.

[0082] It should be noted that each wheel 222 is driven by a corresponding driver 221. In this embodiment, the structures of the two drivers 221 are set to be the same.

[0083] In this embodiment, the dual-wheel drive module further includes a first angle encoder 300 and two second angle encoders (not shown in the figure). The first angle encoder 300 is used to detect the rotation angle of the support frame 210 relative to the guide ring 100. The two second angle encoders are respectively arranged corresponding to the two wheels 222 and are used to detect the rotation angles of the corresponding wheels 222, so as to achieve more precise differential control.

[0084] For example, in this embodiment, the first angle encoder 300 includes a paired encoder stator 310 and an encoder rotor 320. The encoder stator 310 is connected to the side of the mounting plate 120 facing the cylinder body 110, and the encoder rotor 320 is connected to the top plate 212. It should be understood that the cooperation relationship between the encoder stator 310 and the encoder rotor 320 and their operating principles are well-known prior arts. In this embodiment, to avoid repetition, no detailed description is given, and reference can be made to the prior art.

[0085] In the dual-wheel drive module provided in this embodiment, the support frame 210 and the guide ring 100 realize the functions of rotation and swing through the transmission structure of the first positioning wheel 2181, the second positioning wheel 2182, the first limiting wheel 2191, and the second limiting wheel 2192 cooperating with the guide groove 114. Compared with the prior art that uses a complete inner and outer ring slewing bearing, the structure is simplified, the volume is reduced, and the cost is lowered. At the same time, the support frame 210 can swing relative to the guide ring 100 during operation, has a stronger ability to adapt to complex terrains, and has a wide operating range.

[0086] This embodiment also provides a wheeled transport robot, which includes a dual-wheel drive module.

[0087] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A two-wheel drive module, characterized in that, Comprising: A guide ring and a walking and steering mechanism; the guide ring is provided with an installation through-hole, the walking and steering mechanism includes a support frame and two sets of integrated precision drive units, the support frame is installed in the installation through-hole, the support frame and the guide ring are swingably matched around a preset axis, and the two are rotatably matched around the center line of the installation through-hole, and an included angle exists between the preset axis and the center line; Each of the integrated precision drive units includes a frameless motor and a cycloidal planetary precision speed reducer. The frameless motor and the cycloidal planetary precision speed reducer share a housing and an input crankshaft. The housing is connected to the support frame, and wheels are arranged on the cycloidal planetary precision speed reducer; The two sets of independently controlled integrated precision drive units respectively drive precision gear pairs to drive two wheels; each set of the integrated precision drive units adopts a scheme of integrated precision speed reducer, motor and angle encoder. The precision drive unit improves the control precision of the drive motor through the angle encoder and realizes the accurate output rotation angle of the drive unit through the precision speed reducer; each set of the precision gear pairs includes high-precision straight-tooth cylindrical involute gears, and the high-speed stage gears of the precision gear pairs are composed of two gears with phase offset to form a gear pair meshing clearance elimination mechanism to improve the motion output precision of the gear pair; The cycloidal planetary precision speed reducer includes an input end plate, an output end plate, cycloidal wheels, a pin tooth assembly, a stud assembly, an input crankshaft, angular contact ball bearings, deep groove ball bearings and cylindrical rollers; the pin tooth assembly and the cycloidal wheels form a rolling cycloidal pin tooth meshing pair, the stud assembly and the cycloidal wheels, the input end plate and the output end plate form a pin shaft type output mechanism, and the input crankshaft axially passes through the cycloidal wheels. At the same time, the input crankshaft and the cycloidal wheels are rotationally matched through full complement cylindrical rollers; The pin tooth assembly is composed of circumferentially evenly distributed pin teeth and pin tooth sleeves; the pin tooth assembly and the cycloidal wheels form a cycloidal pin tooth meshing pair, and the meshing clearance of the meshing pair is controlled by adjusting the needle roller size of the cycloidal pin tooth meshing pair; The walking and steering mechanism is integrated in the guide ring. A guide raceway is provided on the hole wall of the installation through-hole, and a guide component is provided on the support frame. The guide component and the guide raceway form a rolling contact pair; The guide raceway is set as an arc raceway; the guide component is set as a spherical component; A limiting component is further provided on the support frame. The limiting component is used to abut against the guide raceway when the walking and steering mechanism swings around the preset axis to limit the swing amplitude of the walking and steering mechanism; the limiting component is provided with a spherical surface in contact with the guide raceway; the limiting component is set as a first limiting wheel and a second limiting wheel installed at both ends of the central axis; The two-wheel drive module further includes a first angle encoder for detecting the rotation angle of the support frame relative to the guide ring; the first angle encoder includes a paired encoder stator and encoder rotor. The encoder stator is connected to the guide ring, and the encoder rotor is connected to the support frame.

2. The two-wheel drive module according to claim 1, wherein: The pin assembly includes a pin and a pin sleeve; the left end of the pin is in interference fit with the holes uniformly distributed on the output end plate, a threaded hole is provided at the right end of the pin, and the pin passes through the coordinate holes on the cycloid wheel and is connected to the input end plate through screws; the pin sleeve passes through the pin shaft and is located between the pin shaft and the coordinate holes of the cycloid wheel; each of the pin shafts is supported by two independent bushings between the two cycloid wheels, and the clearance between the kinematic pairs of the output mechanism is controlled by adjusting the wall thickness of the pin shaft sleeve.

3. The double-wheel drive module according to claim 1, wherein: An angle encoder is installed between the guide ring and the support frame; an angle encoder stator mounting bracket is provided on the upper part of the guide ring to mount the encoder stator; an angle encoder rotor mounting bracket is provided on the support frame structure to mount the encoder rotor.

4. A wheeled transport robot, characterized in that, The wheeled transport robot includes: The double-wheel drive module according to any one of claims 1-3.

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