Planetary differential wheel for high-speed heavy-load AGV (Automatic Guided Vehicle)

Abstract

The invention provides a planetary differential wheel for a high-speed heavy-load AGV, and belongs to the technical field of automatic guided vehicles. The two planetary speed reducers are respectively mounted below the frame, and the two planetary speed reducers are symmetrically arranged in the left-right direction; the two servo motors are used for driving the planetary reducers to rotate, the servo motors are installed on the outer side of the frame, and output shafts of the servo motors are connected with sun gear spline shafts of the corresponding planetary reducers through keys; the planetary reduction gear is reasonably arranged in the gear train, so that power distribution is more uniform, space is reasonably and effectively applied, torque transmission pressure under the heavy load condition can be effectively dispersed, and gear damage caused by too large local stress is avoided; the rim is of an open structure, the frame can play a role in protection, and the problem that the planetary reduction wheel is seriously heated under the condition of high-speed operation is effectively solved while the safety is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic guided vehicles, and in particular to a planetary differential wheel for high-speed and heavy-load AGVs. Background Art

[0002] With the continuous development of industrial automation, AGVs are increasingly being used in numerous fields, including logistics, warehousing, and more. The AGV's travel mechanism plays a key role in its overall performance. However, common AGV drive wheels currently have the following shortcomings when operating under heavy loads and at high speeds.

[0003] 1. Traditional differential wheel structures are prone to wheel deformation, increased wear of transmission components, and unstable power transmission when carrying heavy loads, which in turn affects the operating accuracy, speed, and service life of the AGV. For example, utility model patent application number 2023235793677 discloses a differential steering wheel with a suspension. The wheel hub adopts a hollow structure, which makes the wheel hub relatively light, but correspondingly, the wheel body is prone to deformation when carrying heavy loads.

[0004] To address this issue, we designed a planetary differential gear structure specifically for heavy loads. This design incorporates the planetary gear assembly inside the wheel rim, improving the rim's load-bearing capacity and making more efficient use of space. A search revealed utility model application number 2023202281998, which discloses an integrated AGV wheel assembly. In this disclosed solution, a gear reduction mechanism is incorporated into the wheel, further enhancing its load-bearing capacity.

[0005] However, during the testing process, some disadvantages of this structure were discovered: under high-speed operation, the heat dissipation capacity of the existing differential wheel could not meet the demand, resulting in the dynamic balance and overall stability being unable to meet the requirements of efficient and reliable operation.

[0006] 2. Due to the differential driving of the dual motors and the uneven ground, the two differential wheels will generate high-frequency vibration during high-speed operation. If encountering special ground conditions, the running straightness will suddenly become unstable and the differential wheels will swing greatly, affecting the navigation accuracy and causing unpredictable safety hazards. Summary of the Invention

[0007] The present invention provides a planetary differential wheel for high-speed and heavy-load AGV to solve the technical problems in the prior art.

[0008] To solve the above problems, the planetary differential wheel for high-speed and heavy-load AGV provided by the present invention adopts the following technical solutions:

[0009] Including frame;

[0010] Two planetary reducers, the two planetary reducers are respectively installed under the frame, and the two planetary reducers are symmetrically arranged in the left and right directions;

[0011] Two servo motors, the servo motors are used to drive the planetary reducer to rotate. The servo motors are installed on the outside of the frame, and the output shafts of the servo motors are connected to the sun gear spline shafts of the corresponding planetary reducers through keys;

[0012] Two rims, the two rims are respectively mounted on the two planetary reducers, the outer sides of the rims are wrapped with tires, and the rims are open structures;

[0013] The hinge support is installed above the frame and is used to balance the uneven road surface;

[0014] A slewing bearing is mounted on the hinge support, wherein the outer ring of the slewing bearing is fixedly connected to the hinge support;

[0015] Several braking devices are used to brake the slewing bearing. The braking devices include a gear stopper installed on the transition flange of the slewing bearing, an absolute encoder is connected to the top of the gear stopper, and photoelectric proximity switches are provided on both sides of the gear stopper. A mechanical stopper is fixedly installed on the outer ring of the slewing bearing, and the upper surface of the mechanical stopper is provided with a reflective surface.

[0016] By adopting the above technical solution, the heat dissipation effect of the planetary reducer is improved, and at the same time, the dynamic balance and stability of the planetary differential wheel are improved.

[0017] In this solution, the frame is in an inverted "concave" shape, which is convenient for installing components such as servo motors and can also play a protective role. The two rims are located on the inside of the frame. The gaps between the two rims and between the rims and the frame form a heat dissipation channel, and the rims are an open structure. The open design reserves an effective heat dissipation window for the planetary reducer, which can quickly take away the large amount of heat generated by the high-speed operation of the planetary reducer, effectively ensuring the continuous and stable operation of the equipment.

[0018] The frame and the slewing support are connected by a hinge support. When the road surface is uneven, the hinge support can automatically balance the uneven road surface, making the wheel set move more smoothly.

[0019] The braking device combines electromagnetic braking with mechanical braking. The electromagnetic brake has a fast response speed and can brake quickly in an emergency. The mechanical stop serves as a redundant backup. In special circumstances such as electromagnetic failure during steering and lateral movement of the differential wheel, the wheel body is reliably stopped to avoid damage to cables and other components caused by excessive rotation of the wheel set.

[0020] As a further improvement, heat dissipation fins are connected to the housing of the servo motor to accelerate the heat dissipation of the servo motor.

[0021] By adopting the above technical solution, the heat sink fins have sufficient heat dissipation channels, the heat sink fins increase the heat dissipation area of ​​the servo motor, and quickly take away the heat, ensuring that the servo motor will not experience performance degradation or even failure due to overheating.

[0022] As a further improvement, the gear stopper includes a protective shell, a stator is fixedly installed on the upper part of the protective shell, a coil is wound on the outside of the stator, a locking shaft is rotatably assembled inside the stator, the upper end of the locking shaft extends out of the top of the protective shell and is connected to the encoder, and the lower end of the locking shaft extends out of the bottom of the protective shell and is connected to the transmission gear, and the transmission gear and the slewing bearing are meshed with each other;

[0023] An armature is installed below the stator, and a rotor is provided below the armature. The rotor is sleeved on the locking shaft and is fixedly connected to the locking shaft.

[0024] A mounting plate is provided below the rotor and is fixedly mounted below the interior of the protective shell.

[0025] By adopting the above technical solution, the large swing caused by the high-speed operation of the two differential wheels is effectively avoided. The combination of electromagnetic braking and mechanical braking makes the walking more stable. The electromagnetic braking has a fast response speed and can brake quickly in an emergency. The mechanical stop serves as a redundant backup. During the rotation process, in special circumstances such as electromagnetic failure, the wheel body is guaranteed not to rotate excessively, which ensures that the circuit will not be twisted and leaked, and ensures the safety of the AGV in posture movements such as turning and lateral movement.

[0026] As a further improvement, an elastic element is provided between the stator and the armature, and the elastic element squeezes the armature so that the armature and the rotor fit tightly.

[0027] By adopting the above technical solution, the armature can, in a natural state, rely on its own gravity and the extrusion force of the elastic element to tightly squeeze the rotor, so that the rotor fits tightly on the mounting plate, ensuring that the gear stopper is in a braking state when no power is applied.

[0028] As a further improvement, friction surfaces are provided on both the upper and lower sides of the rotor, and a plurality of heat dissipation holes are distributed on the outer circumference of the rotor to facilitate the rapid dissipation of heat generated by friction during braking.

[0029] The adoption of the above technical solution is conducive to improving the service life of the rotor. During the braking process, the rotor will generate a large amount of heat due to friction. If it is not dissipated in time, it will easily affect the braking performance of the rotor. By evenly distributing a number of heat dissipation holes on the outer circumference of the rotor, the heat dissipation area is increased, thereby improving the service life of the brake disc.

[0030] As a further improvement, the two photoelectric proximity switches are arranged at 150 degrees and are distributed symmetrically with respect to the longitudinal direction of the vehicle frame.

[0031] The above technical solution further ensures the stable operation of the planetary differential. In real-world applications, AGVs often need to perform steering maneuvers in complex and changing environments. For example, in logistics warehouses, they must navigate narrow aisles or maneuver around numerous equipment in industrial production workshops. During these steering operations, although AGVs have pre-set control programs to ensure operation, they are inevitably subject to program runaway due to factors such as electromagnetic interference and system failures. Once the program goes out of control, the differential wheel may rotate excessively, causing the AGV to lose directional control and resulting in adverse consequences such as collision damage to cargo and scratches on equipment. The two sets of photoelectric proximity switches, with their high-precision sensing capabilities, can keenly detect subtle changes in the differential wheel rotation angle. In the event of a critical overrotation caused by program runaway, they can intervene promptly and send an alarm signal to the AGV's core control system, enabling the system to quickly respond and correct the abnormal differential wheel rotation, thereby ensuring the AGV continues on a safe trajectory. This ingenious sensor configuration adds a layer of protection to the safety of AGVs, making them more reliable and safer when dealing with complex working conditions and unexpected situations than equipment without such protection, and enabling them to better serve many fields such as logistics, transportation, and industrial production.

[0032] The beneficial effects of the above technical solution of the present invention are as follows:

[0033] 1. The present invention rationally configures the planetary reduction gear and integrates it into the gear train, making the power distribution more uniform and the space being used rationally and effectively. It can effectively disperse the torque transmission pressure under heavy load and avoid gear damage caused by excessive local stress.

[0034] 2. The wheel rim adopts an open structure, and the frame can play a protective role. While ensuring safety, it effectively solves the problem of severe heating of the planetary reduction gear under high-speed operation. At the same time, the servo motor is equipped with heat dissipation fins on the outside to accelerate the heat dissipation of the servo motor.

[0035] 3. The setting of the braking device effectively avoids the large swing caused by the high-speed operation of the two differential wheels. The combination of electromagnetic braking and mechanical braking makes the walking more stable. The electromagnetic braking has a fast response speed and can brake quickly in an emergency. The mechanical stopper serves as a redundant backup. During the rotation process, in special circumstances such as electromagnetic failure, it ensures that the wheel body will not rotate excessively, ensuring that the circuit will not be twisted and leaked, and ensuring the safety of the AGV in posture movements such as turning and lateral movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an illustrative and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0037] Figure 1 A perspective view of a planetary differential gear for a high-speed and heavy-load AGV according to the present invention;

[0038] Figure 2 A side view of a planetary differential gear for a high-speed and heavy-load AGV according to the present invention;

[0039] Figure 3 for Figure 2 AA cross-sectional view;

[0040] Figure 4 This is a schematic structural diagram of the gear stopper of the planetary differential wheel for high-speed and heavy-load AGV according to the present invention.

[0041] Description of reference numerals:

[0042] 1. Braking device; 2. Mechanical stop; 3. Slewing bearing; 4. Frame; 5. Servo motor; 6. Tire; 7. Hinge support; 8. Photoelectric proximity switch; 9. Absolute encoder; 10. Stator; 11. Protective shell; 12. Coil; 13. Armature; 14. Rotor; 15. Mounting plate; 16. Locking shaft; 17. Transmission gear. DETAILED DESCRIPTION

[0043] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0044] In existing technologies, the existing differential wheels' heat dissipation capacity is insufficient at high speeds, resulting in inadequate dynamic balance and overall stability for efficient and reliable operation. Due to the dual-motor differential driving and uneven terrain, the two differential wheels generate high-frequency vibrations during high-speed operation. In unusually rough terrain, operating straightness can suddenly destabilize, causing the differential wheels to swing significantly, impacting navigation accuracy and creating unforeseen safety risks.

[0045] To address the above issues, the present invention designs a differential wheel with an open structure. The inverted "concave" shaped frame can protect the rim and ensure safety. A gap is reserved between the rim and the frame. The heat generated by the planetary reducer can be discharged through the opening on the side of the rim, and then quickly discharged through the heat dissipation channel between the rim and the frame.

[0046] The frame and the slewing support are connected by a hinge support. When the road surface is uneven, the hinge support can automatically balance the uneven road surface, making the wheel set move more smoothly.

[0047] The braking device uses a combination of electromagnetic braking and mechanical braking to make walking more stable. The electromagnetic braking has a fast response speed and can brake quickly in an emergency. The mechanical stop serves as a redundant backup. During the rotation process, in special circumstances such as electromagnetic failure, the wheel body will not rotate excessively, ensuring that the circuit will not be twisted and leaked, ensuring the safety of the AGV in posture movements such as turning and lateral movement.

[0048] In addition, the upper surface of the mechanical stop is also provided with a reflective surface for cooperating with the photoelectric proximity switch. In the critical moment when the program is out of control and causes excessive rotation, the mechanical stop can trigger the photoelectric proximity switch, intervene in time and send an alarm signal to the core control system of the AGV, allowing the system to respond quickly and correct the abnormal rotation of the differential wheel, thereby ensuring that the AGV continues to travel along a safe trajectory.

[0049] After introducing the basic principles of the present invention, various non-limiting embodiments of the present invention are described in detail below. The numbers of any elements in the drawings are for illustration only and not for limitation, and any names are for distinction only and do not have any limiting meaning.

[0050] The principles and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0051] Example 1 of the planetary differential wheel for high-speed and heavy-load AGV provided by the present invention:

[0052] like Figure 1-Figure 4 As shown, it includes a frame 4, planetary reducers installed on both sides of the frame 4, wheel rims installed on the outside of the planetary reducers, a servo motor 5 for driving the planetary reducers to rotate, a slewing bearing 3 installed above the frame 4, and a braking device 1 for braking the slewing bearing 3;

[0053] like Figure 1 As shown, in this embodiment, the frame 4 adopts an inverted "concave" shape structure, which is convenient for installing various components on the one hand, and can protect the rim on the other hand.

[0054] Two planetary reducers are respectively installed under the frame 4. The two planetary reducers are symmetrically arranged along the left and right directions. The planetary reducers are existing technologies and their structures are not described in detail here.

[0055] Two servo motors 5 are provided. The servo motors 5 are used to drive the planetary reducer to rotate. The servo motors 5 are installed on the outside of the vehicle frame 4. The output shaft of the servo motor 5 is connected to the sun gear spline shaft of the corresponding planetary reducer through a key. In this embodiment, heat dissipation fins are arranged on the housing of the servo motor 5. The heat dissipation fins increase the heat dissipation surface area and can quickly take away the heat, ensuring that the motor will not experience performance degradation or even failure due to overheating.

[0056] like Figure 1 and Figure 3 As shown, the two rims are respectively mounted on the two planetary reducers, and the outer side of the rims is wrapped with tires 6. The rims are open structures, which effectively solve the problem of severe heating of the planetary reducer when operating at high speed.

[0057] like Figure 1 and Figure 3 As shown, the frame 4 is connected to the slewing bearing 3 through a hinge support 7, and the hinge support 7 is used to balance the uneven road surface; when the road surface is uneven, the frame 4 can rotate along the hinge axis of the hinge support 7, thereby automatically adjusting the angle to achieve automatic balancing of the uneven road surface, making the wheel group run smoother.

[0058] like Figure 1 As shown, the slewing bearing 3 is installed on the hinge support 7, the outer ring of the slewing bearing 3 is fixedly connected to the hinge support 7, and the inner ring of the slewing bearing 3 is fixedly connected to the external vehicle body.

[0059] like Figure 1 and Figure 4 As shown, the braking device 1 is used to brake the slewing bearing 3. In this embodiment, the braking device 1 is a group, and in other embodiments, multiple groups can also be provided.

[0060] The braking device 1 includes a gear stopper mounted on the transition flange of the slewing bearing 3. The transition flange is fixedly connected to the inner ring of the slewing bearing 3. An absolute encoder 9 is connected to the top of the gear stopper. Photoelectric proximity switches 8 are provided on both sides of the gear stopper. A mechanical stopper 2 is fixedly mounted on the outer ring of the slewing bearing 3. The upper surface of the mechanical stopper 2 is provided with a reflective surface. A limiting structure that cooperates with the mechanical stopper 2 is also fixedly mounted on the external vehicle body.

[0061] In this embodiment, the photoelectric proximity switches 8 are fixedly mounted on the outer vehicle body. The two photoelectric proximity switches 8 are arranged at 150 degrees and are longitudinally symmetrically distributed with respect to the vehicle frame 4 (in this embodiment, the safe range of rotation of the slewing bearing 3 is within 150 degrees).

[0062] The absolute encoder 9 is mainly used for precise position detection and feedback, such as determining the initial position, real-time position tracking, etc.

[0063] Determine the initial position: Before the slewing mechanism is started, the absolute encoder 9 can accurately identify the initial angular position of the gear stop, providing an accurate reference point for the subsequent operation of the entire system.

[0064] Real-time position tracking: During the operation of the rotary mechanism, the absolute encoder 9 can continuously and accurately measure the real-time position angle information of the gear stopper and the rotating parts associated with it, and feed it back to the control system.

[0065] The gear stopper includes a protective shell 11, a stator 10 is fixedly mounted on the upper part of the protective shell 11, a coil 12 is wound around the outer side of the stator 10, and a locking shaft 16 is rotatably mounted inside the stator 10. The upper end of the locking shaft 16 extends out of the top of the protective shell 11 and is connected to the encoder, and the lower end of the locking shaft 16 extends out of the bottom of the protective shell 11 and is connected to the transmission gear 17, which is meshed with the slewing bearing 3;

[0066] An armature 13 is mounted below the stator 10, and a rotor 14 is mounted below the armature 13. The rotor 14 is sleeved on a locking shaft 16 and is fixedly connected to the locking shaft 16.

[0067] A mounting plate 15 is provided below the rotor 14 and is fixedly mounted on the lower interior of the protective shell 11 .

[0068] An elastic element (not shown) is provided between the stator 10 and the armature 13 . The elastic element squeezes the armature 13 so that the armature 13 and the rotor 14 fit tightly together. In this embodiment, the elastic element is a return spring.

[0069] The rotor 14 is provided with friction surfaces on both the upper and lower sides. The outer circumference of the rotor 14 is provided with a plurality of heat dissipation holes to facilitate the rapid dissipation of heat generated by friction during braking.

[0070] The working principle of the gear stop is:

[0071] In the initial state, when no power is supplied, the entire device relies on the interaction between the mechanical structures to maintain the braking state. In its natural state, the armature 13, due to its own gravity, the force applied by elastic elements (such as return springs), or the limiting effect of the mechanical structure, tightly compresses the rotor 14, causing the rotor 14 to fit tightly against the mounting plate 15, restricting the rotation of the locking shaft 16. This, in turn, limits the rotational freedom of the slewing bearing 3 through the transmission gear 17, achieving the braking effect.

[0072] When power is supplied, the energized coil 12 generates a magnetic field according to the principle of electromagnetic induction. The magnetic field strength generated by the coil 12 is sufficient to overcome the force (such as gravity, elastic force of elastic elements, etc.) that the armature 13 is originally subjected to, which causes it to squeeze the rotor 14, thereby attracting the armature 13 to the side of the stator 10.

[0073] As the armature 13 is attracted to the stator 10, the squeezing effect of the armature 13 on the rotor 14 disappears, and the rotor 14 is no longer restricted by the armature 13 and is able to break away from the mounting plate 15. Due to the connection between the rotor 14 and the shaft and gear, the rotor 14 can rotate freely, thereby driving the shaft and gear connected thereto to rotate freely. At this point, the gear is no longer in a braking state and can operate normally with the external driving force or the transmission system connected thereto. For example, when the automation equipment needs to be restarted, the power is turned on to release the gear stopper, and the gear can participate in the entire transmission chain, driving the subsequent mechanical components to perform corresponding production operations, etc., to ensure that the normal working process of the equipment can continue.

[0074] Although this specification has shown and described a number of embodiments of the present invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art will conceive of many modifications, changes, and alternatives without departing from the ideas and spirit of the present invention. It should be understood that in practicing the present invention, various alternatives to the embodiments of the present invention described herein may be employed. The appended claims are intended to define the scope of protection of the present invention and therefore cover modular compositions, equivalents, or alternatives within the scope of protection of these claims.

Claims

1. A planetary differential wheel for high-speed and heavy-load AGV, comprising: Frame (4); It is characterized by further comprising: Two planetary reducers, the two planetary reducers are respectively installed below the vehicle frame (4), and the two planetary reducers are symmetrically arranged along the left-right direction; Two servo motors (5), the servo motors (5) are used to drive the planetary reducer to rotate, the servo motors (5) are installed on the outside of the frame (4), and the output shafts of the servo motors (5) are connected to the sun gear spline shafts of the corresponding planetary reducers through keys; Two wheel rims, the two wheel rims are respectively mounted on the two planetary reducers, the outer sides of the wheel rims are wrapped with tires (6), and the wheel rims are of an open structure; A hinge support (7) is installed above the vehicle frame (4), and the hinge support (7) is used to balance the uneven road surface; A slewing bearing (3) is mounted on a hinge support (7), wherein the outer ring of the slewing bearing (3) is fixedly connected to the hinge support (7); A plurality of braking devices (1) are used to brake a slewing bearing (3), wherein the braking devices (1) include a gear stopper mounted on a transition flange of the slewing bearing (3), an absolute encoder (9) being connected to the top of the gear stopper, photoelectric proximity switches (8) being provided on both sides of the gear stopper, and a mechanical stopper (2) being fixedly mounted on the outer ring of the slewing bearing (3), and a reflective surface being provided on the upper surface of the mechanical stopper (2).

2. The planetary differential wheel for high-speed and heavy-load AGV according to claim 1, characterized in that: The housing of the servo motor (5) is connected with heat dissipation fins to accelerate the heat dissipation of the servo motor (5).

3. The planetary differential wheel for high-speed and heavy-load AGV according to claim 1, characterized in that: The gear stopper comprises a protective shell (11), a stator (10) is fixedly installed on the upper part of the protective shell (11), a coil (12) is wound around the outer side of the stator (10), a locking shaft (16) is rotatably mounted inside the stator (10), the upper end of the locking shaft (16) extends out of the top of the protective shell (11) and is connected to an encoder, and the lower end of the locking shaft (16) extends out of the bottom of the protective shell (11) and is connected to a transmission gear (17), and the transmission gear (17) and the slewing bearing (3) are meshed with each other; An armature (13) is installed below the stator (10), a rotor (14) is provided below the armature (13), the rotor (14) is sleeved on a locking shaft (16), and the rotor (14) is fixedly connected to the locking shaft (16); A mounting plate (15) is provided below the rotor (14) and is fixedly mounted below the interior of the protective shell (11).

4. The planetary differential wheel for high-speed and heavy-load AGV according to claim 3, characterized in that: An elastic element is provided between the stator (10) and the armature (13), and the elastic element squeezes the armature (13) so that the armature (13) and the rotor (14) are closely fitted.

5. The planetary differential wheel for high-speed and heavy-load AGV according to claim 3 or 4, characterized in that: The rotor (14) is provided with friction surfaces on both upper and lower sides, and the outer circumference of the rotor (14) is evenly distributed with a plurality of heat dissipation holes, so as to facilitate the rapid dissipation of heat generated by friction during braking.

6. The planetary differential wheel for high-speed and heavy-load AGV according to claim 1, characterized in that: The two photoelectric proximity switches (8) are arranged at 150 degrees and are distributed symmetrically with the vehicle frame (4) in the longitudinal direction.

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