Patent Description:
The current automated guided vehicle (AGV) is mostly driven by a differential drive device. The differential drive device refers to an integrated mechanical structure which integrates a drive motor, a reducer, a driving wheel, etc. Compared with the traditional AGV differential control mode, the differential drive device has high integration and strong adaptability, which can rapidly deploy AGVs, mobile robots, etc..

The slewing bearing is generally used to realize the rotation connection between the differential drive device and the vehicle body. However, the slewing bearing must occupy the height of the differential drive device in the vertical direction, which leads to the problem that the total height of the differential drive device is relatively large and its application is limited in the scene with high requirements for height space.

Also, in the art are known some methods or devices as described in their respective documents.

For example, <CIT> discloses a transport and lifting unit in which both a height adjustment is integrated and a reliable load pick-up and transport is possible and which can also be used universally and independently and can be moved as desired. Self-propelled transport and lifting unit (<NUM>) for lifting and moving objects (<NUM>), comprising a controller, an energy supply, two drive wheels (<NUM>), each with its own drive, a centrally and vertically arranged nut/spindle unit (<NUM>, <NUM> ), wherein in the transport and lifting unit (<NUM>) there is an internal thread (<NUM>) for the nut/spindle unit (<NUM>, <NUM>) and the spindle (<NUM>) is arranged in the internal thread (<NUM>) and wherein at the upper end of the A lifting plate (<NUM>) is arranged on the spindle (<NUM>), the lifting plate (<NUM>) being connected to the spindle (<NUM>) in a torsion-proof manner and the axis of rotation of the drive wheels (<NUM>) crossing the axis of rotation of the spindle (<NUM>).

<CIT> discloses a novel super-thin AGV carrier. The novel super-thin AGV carrier is composed of two vehicle body units of the same front and back structure, and the two vehicle body units are connected through middle telescopic connecting mechanisms. Each vehicle body unit comprises a walking part, a wheel holding lifting part and a frame structure. Each walking part comprises two driving wheel modules and four driven wheel modules, wherein the driving wheel modules are used for achieving plane all-direction walking of a carrier body, and the driven wheel modules are used for assisting driving wheels to share load weight and balance and support the vehicle body. Each wheel holding lifting part comprises two wheel holding lifting assemblies located on the two sides of the corresponding frame structure. Each wheel holding lifting assembly comprises a driving mechanism, a transmission mechanism and a wheel holding mechanism, wherein the driving mechanism provides power output, the transmission mechanism achieves movement speed reduction and power amplification, and the wheel holding mechanism finally lifts a vehicle away from the ground.

<CIT> discloses a low-profile robotic mover of pallets, carts or other loads includes multiple, independently operated compact drive units housed into separate but connected structural elements of the device. These connection(s) pivot and telescope and can be locked in a telescoped position. This invention can also uses differential drive units which then provides many features beneficial to robotic load moving devices. This device remains ultra-low profile even when heavy loads need to be lifted and moved as more drive units can be added as needed. The pivoting/telescoping connections between structural elements allows the device to modify its own size or shape to better match the dimensions of the load to be moved. Combining the connecting pivot(s) with the with the drive wheel assembly pivots means all driven wheels maintain traction regardless of wheel orientation or variations in floor height or angles, allowing the device to automatically and predictably navigate uneven floors.

An object of the embodiments of the present application is to provide a differential drive device and an AGV to effectively reduce the total height of the differential drive device. The specific technical solutions are as follows:
An embodiment of the present application provides a differential drive device including a differential drive unit, a top plate and an outer cover. The top plate is installed on a top end of the outer cover. The differential drive unit is located in the outer cover at a lower side of the top plate. The top plate is supported above the differential drive unit. An inner side wall of the outer cover is characterized in that a first rolling member is provided on a side of the differential drive unit. The first rolling member is in rolling connection with the lower side of the top plate.

Optionally, two first rolling members are installed on the side of the differential drive unit. The two first rolling members are arranged symmetrically about a center of slewing of the differential drive unit.

Optionally, a second rolling member is provided on the side of the differential drive unit. The second rolling member is in rolling connection with the inner side wall of the outer cover.

Optionally, two second rolling members are installed on the side of the differential drive unit. The two second rolling members are arranged symmetrically about the center of slewing of the differential drive unit.

Optionally, a first rolling member is provided on the side of the differential drive unit. The first rolling member is in rolling connection with the lower side of the top plate. An end of the first rolling member close to the inner side wall of the outer cover is provided with a groove, and a second rolling member is installed in the groove. The second rolling member partially protrudes out of the groove and is rotatably connected to the inner side wall of the outer cover.

Optionally, the second rolling member is a roller bearing. A bearing seat is provided on a side wall of the differential drive unit, and the roller bearing is installed on the bearing seat.

Optionally, a top end of the first rolling member is higher than the differential drive unit. A slewing diameter of the differential drive unit is smaller than an inner diameter of the outer cover.

Optionally, a pin shaft is provided on the side of the differential drive unit. An annular limiting slot is provided at a position on the inner side wall of the outer cover corresponding to the pin shaft. An end of the pin shaft close to the outer cover is located in the limiting slot.

Optionally, the differential drive unit includes a first motor, a second motor, a first reducer, a second reducer, a first driving wheel and a second driving wheel, wherein the first motor and the second motor are arranged side by side, and output shafts of the first motor and the second motor face away from each other; the first reducer is connected to the output shaft of the first motor, and the second reducer is connected to the output shaft of the second motor; the first driving wheel is installed on a side of the first reducer facing away from the first motor, and the second driving wheel is installed on a side of the second reducer facing away from the second motor.

Optionally, a through-hole is provided on the top plate, and the differential drive unit is connected to the AGV through the through-hole.

Optionally, the differential drive unit further includes: a support body;.

Optionally, the support is a horizontal support plate, and the differential drive unit is arranged below the horizontal support plate.

Optionally, the differential drive device further includes a connecting shaft. The differential drive unit and the horizontal support plate are connected by the connecting shaft, and a central axis of the connecting shaft coincides with the transverse axis.

Optionally, the support body includes two vertical plates arranged at intervals, and the differential drive unit is arranged between the two vertical plates.

Optionally, the differential drive device further includes a connecting shaft, the two vertical plates and the differential drive unit are connected by the connecting shaft, and the central axis of the connecting shaft coincides with the transverse axis.

Optionally, a ring-shaped limiting slot is formed on the side wall of the receptacle cavity. The end of the connecting shaft extends out of the differential drive unit and is arranged in the limiting slot.

Optionally, the differential drive device further includes a first rolling member, and the first rolling member is arranged between the differential drive unit and the outer cover or between the support body and the outer cover.

Optionally, the first rolling member is a ball, a roller or a bearing.

Optionally, the differential drive device further includes a plurality of second rolling members arranged on the support body, and the support body supports the top plate through the plurality of second rolling members.

Optionally, the second rolling member is a ball, a roller or a bearing.

Optionally, the differential drive unit includes a driving wheel and a power unit connected to the driving wheel, and the power unit is hinged to the support body.

Optionally, an axle of the driving wheel is perpendicular to the transverse axis.

The embodiment of the present application further provides an AGV including the differential drive device described above.

The embodiment of the present application provides a differential drive device and an AGV. A differential drive unit is located in an inverted barrel-shaped container composed of a top plate and an outer cover. The top plate is supported by the differential drive unit, and a bottom end of the outer cover is higher than a bottom end of the differential drive unit, so that the differential drive unit can move away from the top plate and the outer cover. Since the differential drive unit itself can rotate, the differential drive unit can rotate relative to the top plate and the outer cover. In summary, the differential drive device can realize the functions of differential rotation in-situ and forward and backward walking. The differential drive device according to the present embodiment uses the top plate and the outer cover instead of a slewing bearing. Since the thickness of the top plate can be much smaller than the height of the slewing bearing, the differential drive device according to the present embodiment can effectively reduce the total height of the differential drive device.

In order to more clearly describe the technical solutions of the embodiments of the present application or of the prior art, drawings that need to be used in embodiments and the prior art will be briefly described below. Obviously, the drawings provided below are for only some embodiments of the present application; those skilled in the art can also obtain other drawings based on these drawings without any creative efforts.

In order to make the objectives, technical solutions, and advantages of the present application clearer and more understandable, the present application will be described in more detail below with reference to the appended drawings and embodiments. Obviously, the described embodiments are only some, and not all, of the embodiments of the present application. All other embodiments obtained based on the embodiments of the present application by those skilled in the art without any creative efforts fall into the scope of protection defined by the present application.

The embodiments of the present application provide a differential drive device and an AGV, which can effectively reduce the total height of the differential drive device.

<FIG> are schematic structural diagrams of the differential drive device according to an embodiment of the present application. As shown in <FIG>, the differential drive device of this embodiment includes a differential drive unit <NUM>, a top plate <NUM> and an outer cover <NUM>. The top plate <NUM> is installed on a top end of the outer cover <NUM>. The differential drive unit <NUM> is located in the outer cover <NUM> at a lower side of the top plate <NUM>. The top plate <NUM> is supported above the differential drive unit <NUM>. An inner side wall of the outer cover <NUM> is circular-shaped.

In this embodiment, the differential drive unit refers to an integrated mechanical structure which integrates a drive motor, a reducer and a driving wheel, which can not only travel in a straight line and can also realize the function of steering. The differential drive unit is located in an inverted barrel-shaped container composed of the top plate and the outer cover, and the top plate is supported above the differential drive unit, i.e. the top plate is supported by the differential drive unit. A bottom end of the outer cover is higher than a bottom end of the differential drive unit, so that the differential drive unit can move away from the top plate and the outer cover.

Also, since the differential drive unit itself can rotate, the differential drive unit can rotate relative to the top plate and the outer cover. At this time, sliding friction occurs between the top end of the differential drive unit and the top plate, and sliding friction occurs between the side of the differential drive unit and the inner side wall of the outer cover. In summary, the differential drive device can realize the functions of differential rotation in-situ and forward and backward walking.

When the differential drive device is applied to an AGV, the AGV refers to a transport vehicle equipped with electromagnetic or optical automatic guidance devices, which can travel along a defined guidance path, have safety protection and various transfer functions. The AGV belongs to the category of Wheeled Mobile Robot (WMR).

Optionally, a through-hole is provided on the top plate, and the differential drive unit is connected to the automated guided vehicle through the through-hole.

The top plate and/or the outer cover is fixed on the body of the AGV, and the through-hole can be open on the top plate. The wiring between the differential drive unit and the AGV is realized through the through-hole opened on the top plate (for example, motor power supply line of the differential drive unit needs to be connected to battery of the AGV), that is, the differential drive device is applied to the AGV, thereby realizing the relative rotation between the differential drive unit and the vehicle body. The differential drive device provided by this embodiment uses the top plate and the outer cover instead of the slewing bearing. Since the thickness of the top plate can be much smaller than the height of the slewing bearing, the differential drive device provided by this embodiment can effectively reduce the total height of the differential drive device.

As shown in <FIG>, a first rolling member <NUM> is provided on a side of the differential drive unit <NUM>. The first rolling element <NUM> is in rolling connection with the lower side of the top plate <NUM>.

In this embodiment of the invention, when the differential drive unit rotates relative to the top plate, the first rolling member rotatably connected to the lower side of the top plate can reduce the friction between the differential drive unit and the top plate, thereby reducing the wear of the differential drive unit and the top plate, extending the service life of the differential drive device, and improving the motion accuracy of the differential drive unit. In addition, the first rolling member is arranged at the side instead of the top of the differential drive unit, which can reduce the influence of the overall height of the first rolling member on the total height of the differential drive device. For example, when installing the first rolling member, the highest point of the first rolling member should be higher than the differential drive unit. As for the height difference between the highest point of the first rolling member and the highest point of the differential drive unit, it can be adjusted accordingly according to actual needs. In this embodiment, the first rolling member is installed at the side of the differential drive unit, which can effectively reduce the overall height of the differential drive unit compared with the current technical solution where the slewing bearing is installed on the top end of the differential drive unit.

As shown in <FIG>, optionally, two first rolling members <NUM> are installed on the side of the differential drive unit <NUM>. The two first rolling members <NUM> are arranged symmetrically about a center of slewing of the differential drive unit <NUM>.

In this embodiment, the two first rolling members are arranged symmetrically about the center of slewing of the differential drive unit, which can balance the force when the differential drive unit contacts the top plate, thereby reducing the situation that the differential drive unit tilts under the pressure of the top plate. In turn, the stability of the differential drive device is improved.

As shown in <FIG>, optionally, the first rolling member <NUM> can be a roller bearing. The roller bearing has the characteristics of simple installation structure and easy installation. Therefore, the use of the roller bearing for the first rolling member can simplify the structure of the differential drive device and improve the assembly efficiency of the differential drive device.

It can be understood that the first rolling member can also be a ball, a bullseye wheel, etc., which can also achieve the effect of reducing the friction between the differential drive unit and the top plate.

As shown in <FIG>, in the case of the first rolling member <NUM> being the roller bearing, optionally, a side plate <NUM> is connected to the side of the differential drive unit <NUM>, and the roller bearing is installed on the side plate <NUM>.

In this embodiment, an axis of the first rolling member is horizontal. The rolling connection between the roller bearing and the top plate can be realized by installing a shaft head of the roller bearing on the side plate. And the roller bearing and the top plate are in line contact, which can reduce the local force on the top plate and increase the service life of the top plate. In addition, the installation method of the roller bearing is simple. For example, if the roller bearing with threads on the shaft head and the side plate with threaded holes are selected, the roller bearing and the side plate can be connected by threads. The threaded connection method is simple and reliable, which improves the convenience of installation and disassembly of the first rolling member.

Also, the first rolling member is installed on the side plate instead of directly on the differential drive unit, which can reduce the installation positions on the differential drive unit and improve the structural strength of the differential drive unit. After the first rolling member is assembled with the side plate as a whole, it can be connected to the side wall of the differential drive unit by a fastener.

As shown in <FIG>, optionally, when the two first rolling members <NUM> are installed on the side of the differential drive unit <NUM>, the two first rolling members <NUM> are symmetrically arranged about the center of slewing of the differential drive unit <NUM>, and the center axis of slewing of the roller bearing can be perpendicular to and intersect with the center axis of slewing of the differential drive unit <NUM> when the first rolling member <NUM> is a roller bearing and is installed on the side of the differential drive unit <NUM>.

In this embodiment, the roller bearing is arranged as described above, which can reduce the rolling friction between the roller bearing and the top plate, and can also balance the force on the two symmetrically arranged roller bearings, so that the differential drive unit can achieve differential rotation in situ as much as possible.

As shown in <FIG>, optionally, a second rolling member <NUM> is provided on the side of the differential drive unit <NUM>. The second rolling member <NUM> is in rolling connection with the inner side wall of the outer cover <NUM>.

In this embodiment, when the differential drive unit rotates relative to the outer cover, the second rolling member rotatably connected to the inner side wall of the outer cover can reduce the friction between the differential drive unit and the outer cover, thereby reducing the wear of the differential drive unit and the outer cover, extending the service life of the differential drive device, and improving the motion accuracy of the differential drive unit. In addition, the second rolling member is arranged on the side wall instead of the top or the bottom of the differential drive unit, so that the highest point of the second rolling member can be lower than the highest point of the differential drive unit and the lowest point being can be higher than the lowest point of the differential drive unit when arranging the second rolling member. In this way, the second rolling member does not affect the overall height of the differential drive device.

As shown in <FIG>, optionally, the second rolling member <NUM> can also be the roller bearing. In this case, the roller bearing is vertically installed on the side of the differential drive unit. The roller bearing has the characteristics of simple installation structure and easy installation. Therefore, the use of the roller bearing for the second rolling member can simplify the structure of the differential drive device and improve the assembly efficiency of the differential drive device.

As shown in <FIG>, optionally, two second rolling members <NUM> are installed on the side of the differential drive unit <NUM>. The two second rolling members <NUM> are arranged symmetrically about the center of slewing of the differential drive unit <NUM>.

In this embodiment, the two second rolling members are symmetrically arranged on both sides of the differential drive unit, which can not only balance the force on the differential drive unit, but also limit the differential drive unit, thereby reducing the occurrence of the contact between other parts of the differential drive unit and the outer cover during the movement.

As shown in <FIG>, optionally, the second rolling member <NUM> is the roller bearing. A bearing seat <NUM> is provided on the side wall of the differential drive unit <NUM>, and the roller bearing is installed on the bearing seat <NUM>.

In this embodiment, an axis of the roller bearing is vertical. The rolling connection between the roller bearing and the inner wall of the outer cover can be realized by installing a shaft head of the roller bearing on the bearing seat. And the roller bearing and the outer cover are in line contact, which can reduce the local force on the outer cover and increase the service life of the outer cover. In addition, the installation method of the roller bearing is simpler than that of other bearings. For example, if the roller bearing with threads on the shaft head and the mounting seat with threaded holes are selected, the roller bearing and the mounting seat can be connected by threads. The threaded connection method is simple and reliable, which improves the convenience of installation and disassembly of the second rolling member.

It can be understood that the second rolling member can also be a ball, a bullseye wheel, etc., which can also achieve the effect of reducing the friction between the differential drive unit and the outer cover.

As shown in <FIG> and <FIG>, optionally, the first rolling member <NUM> is provided on the side of the differential drive unit <NUM>. The first rolling member <NUM> is in rolling connection with the lower side of the top plate <NUM>. One end of the first rolling member <NUM> close to the inner side wall of the outer cover <NUM> is provided with a groove, and the second rolling member <NUM> is installed in the groove. The second rolling member <NUM> partially protrudes out of the groove and is in rolling connection with the inner side wall of the outer cover <NUM>.

In this embodiment, the differential drive unit is in rolling connection with the top plate through the first rolling member. On the one hand, the first rolling member can reduce the friction between the differential drive unit and the top plate, and on the other hand, it can also be used to carry the force in the vertical direction from the top plate. The differential drive unit is in rolling connection with the inner side wall of the outer cover through the second rolling member. On the one hand, the second rolling member can reduce the friction between the differential drive unit and the outer cover, and on the other hand, it can also be used to carry the force in the horizontal direction from the outer cover. In this embodiment, the first rolling member and the second rolling member are assembled together. Compared with the technical solution in which the first rolling member and the second rolling member are individually installed on the differential drive unit, the installation positions arranged on the differential drive unit can be reduced, thereby improving the structural strength of the differential drive unit.

It can be understood that the number of the first rolling member and the second rolling member is not limited in the embodiments of the present application, and those skilled in the art can make reasonable selections according to actual needs.

As shown in <FIG> or <FIG>, optionally, a top end of the first rolling member <NUM> is higher than the differential drive unit <NUM> (see <FIG> or <FIG>). The slewing diameter of the differential drive unit <NUM> is smaller than an inner diameter of the outer cover <NUM>.

In this embodiment, the first rolling member also constitutes the function of the balance bridge: the differential drive unit is contacted with the top plate through the first rolling member, so the differential drive unit can rotate around the first rolling member, that is, during the operation of the differential drive unit, when the ground is uneven, the differential drive unit can swing around the first rolling member (that is, when one of the driving wheels is raised, the other driving wheel can still keep in contact with the ground). The two driving wheels can be kept in good contact with the ground through this swing, thus reducing the situation that the driving wheels are overhead, which cannot be achieved by using the slewing bearing in the existing differential drive device.

As shown in <FIG> or <FIG>, optionally, when the two first rolling members <NUM> are installed on the side of the differential drive unit <NUM> and the two first rolling members <NUM> are symmetrically arranged about the center of slewing of the differential drive unit <NUM>, the connection line of the two first rolling members <NUM> can be perpendicular to the connection line of the two driving wheels of the differential drive unit <NUM> (see <FIG> or <FIG>).

In this embodiment, the two first rolling members constitutes the function of the balance bridge: the differential drive unit is contacted with the top plate through the two first rolling members, so the differential drive unit can rotate around the connection line of the two first rolling members. When the ground is uneven, the differential drive unit can keep the two driving wheels in good contact with the ground through this swing, thereby avoiding the drive wheels from being overhead.

As shown in <FIG>, optionally, a pin shaft <NUM> is provided on the side of the differential drive unit <NUM>. An annular limiting slot is provided at a position on the inner side wall of the outer cover <NUM> corresponding to the pin shaft <NUM>. An end of the pin shaft <NUM> close to the outer cover <NUM> is located in the limiting slot.

In this embodiment, the limiting slot can limit the differential drive unit, prevent the differential drive unit from coming out of the outer cover, and keep the entire differential drive unit as a whole. This embodiment does not limit the number of the pin shafts, and multiple pin shafts can be arranged on the side of the differential drive unit.

Optionally, the outer cover is provided with an installation slot on the lower side of the limiting slot. An upper end of the installation slot communicates with the limiting slot, and a lower end of the installation slot communicates with the lower side of the outer cover. The installation slot is provided with a sealing block detachably connected to the outer cover. In this embodiment, when the differential drive unit and the outer cover are installed as a whole, the sealing block is firstly removed, then the pin shaft is aligned with the lower end of the installation slot, the differential drive unit is pushed upwards, and until the pin shaft is located in the limiting slot, the sealing block is fixed in the installation slot to prevent the pin shaft from falling out, and it finally plays a role in preventing the differential drive unit from falling out of the outer cover.

In this embodiment, the process of removing the differential drive unit from the outer cover and the process of assembling the differential drive unit with the outer cover as a whole are reverse to each other, and will not be repeated here.

As shown in <FIG> and <FIG>, optionally, the pin shaft <NUM> is installed on the bearing seat <NUM>.

In this embodiment, the pin shaft is installed on the bearing seat, which can reduce the installation positions on the differential drive unit and improve the structural strength of the differential drive unit. Optionally, one end of the pin shaft is provided with threads, the bearing seat is provided with threaded holes, and the pin shaft and the bearing seat are connected through the threaded holes.

As shown in <FIG>, optionally, the differential drive unit <NUM> includes a first motor <NUM>, a second motor <NUM>', a first reducer <NUM>, a second reducer <NUM>', a first driving wheel <NUM> and a second driving wheel <NUM>'; wherein: the first motor <NUM> and the second motor <NUM>' are arranged side by side, and the output shafts of the first motor <NUM> and the second motor <NUM>' face away from each other; the first reducer <NUM> is connected to the output shaft of the first motor <NUM>, and the second reducer <NUM>' is connected to the output shaft of the second motor <NUM>'; the first driving wheel <NUM> is installed on a side of the first reducer <NUM> facing away from the first motor <NUM>, and the second driving wheel <NUM>' is installed on a side of the second reducer <NUM>' facing away from the second motor <NUM>'.

In this embodiment, the first driving wheel is driven by the first motor, and the second driving wheel is driven by the second motor. In the actual movement process, the differential drive unit can realize the functions of differential rotation in-situ and forward and backward walking by controlling the speed and the steering of the first motor and the second motor. In this embodiment, each of the components in the differential drive unit are arranged in a symmetrical manner, which can balance the forces on the two driving wheels of the differential drive unit, thereby enabling the differential drive unit to move more smoothly.

As an optional implementation of the embodiments of the present application, two limiting posts are provided on the side wall of the differential drive unit, a limiting plate is provided on the lower side of the top plate, and the limiting plate is located on the movement track of the limiting posts. In this embodiment, the limiting posts arranged on the side wall of the differential drive unit will rotate with the differential drive unit relative to the top plate; when the differential drive unit is installed on the AGV, the differential drive unit will connect to the AGV through the through-hole opened on the top plate (for example, the motor power supply line needs to be connected to the battery on the AGV). Therefore, the limiting plate on the top plate is matched with the limiting posts arranged on the differential drive unit to limit the rotation angle of the differential drive unit, thereby avoiding the situation that the differential drive unit rotates infinitely relative to the top plate and causes the connection to be twisted off.

Chassis structure of existing AGV is relatively complex and requires higher road surface flatness. Only one driving wheel may land on the ground when driving on the uneven road, resulting in insufficient traction, slipping, out of control and other phenomena.

In order to solve the above technical problems, as shown in <FIG>, an embodiment of the present application provides a differential drive device <NUM>. The differential drive device <NUM> includes a differential drive unit <NUM>, a support body <NUM>, and a mounting frame <NUM> formed by enclosing a top plate <NUM> and an outer cover <NUM>. Specifically, the differential drive unit <NUM> is hinged to the support body <NUM> so that the differential drive unit <NUM> swings around the transverse axis relative to the support body <NUM>. A receptacle cavity is formed in the mounting frame <NUM>, and the support body <NUM> and the differential drive unit <NUM> are arranged in the receptacle cavity. The support body <NUM> supports the mounting frame <NUM>, and the differential drive unit <NUM> is arranged to be rotatable around a longitudinal axis of the receptacle cavity. It can be understood that when the differential drive device <NUM> is applied to an AGV, it can be connected to a bottom of the AGV through the mounting frame <NUM>. The top plate <NUM> and/or the outer cover <NUM> can be used to connect to the vehicle body of the AGV. After the mounting frame <NUM> is connected to the vehicle body, the top plate <NUM> is arranged horizontally.

According to the differential drive device <NUM> of the embodiments of the present application, the receptacle cavity is formed in the mounting frame <NUM>, and the support body <NUM> and the differential drive unit <NUM> are arranged in the receptacle cavity. The support body <NUM> supports the mounting frame <NUM>, and the differential drive unit <NUM> is arranged to be rotatable around a longitudinal axis of the receptacle cavity. At the same time, the differential drive unit <NUM> is hinged to the support body <NUM> so that the differential drive unit <NUM> can swing around the transverse axis relative to the support body <NUM>. As a result, a "universal joint" structure is formed between the differential drive unit <NUM> and the mounting frame <NUM>. That is to say, the differential drive unit <NUM> has two degrees of freedom of rotation relative to the mounting frame <NUM>, first degree of freedom is the degree of freedom that the differential drive unit <NUM> can rotate about the longitudinal axis, and second degree of freedom is the degree of freedom that the differential drive unit <NUM> can swing about the transverse axis. The first degree of freedom is used to realize the steering function of the AGV under the action of the differential drive unit <NUM>, and the second degree of freedom is used to adapt the differential drive unit <NUM> to the fluctuations of the road surface, so that the differential drive unit <NUM> maintains effective contact with the road surface, so as to avoid the phenomenon of slipping and out of control caused by insufficient traction. It can be seen that when the differential drive device <NUM> of the embodiment of the present application is applied to an AGV, it can effectively reduce AGV's requirements for the flatness of the road surface.

Optionally, the support body <NUM> is a horizontal support plate (as shown in <FIG>), and the differential drive unit <NUM> is arranged below the horizontal support plate. The horizontal support plate refers to a plate structure arranged in the horizontal direction. In addition, in the case of the AGV running on the road, a direction parallel to the road surface can be understood as the horizontal direction. In this embodiment, the differential drive unit <NUM> is arranged below the horizontal support body, so that the horizontal support body can support the mounting frame <NUM>.

Optionally, the differential drive device <NUM> further includes a connecting shaft <NUM>. The differential drive unit <NUM> and the horizontal support body are connected by the connecting shaft <NUM>, and a central axis of the connecting shaft <NUM> coincides with the transverse axis. Thus, the differential drive unit <NUM> is hinged to and the support body <NUM>, so that the differential drive unit <NUM> can swing about the transverse axis relative to the support body <NUM>.

Optionally, the support body <NUM> includes two vertical plates <NUM> arranged at intervals (as shown in <FIG>), and the differential drive unit <NUM> is arranged between the two vertical plates <NUM>. The vertical plate <NUM> refers to a plate structure with the plate surface arranged in the vertical direction. In this embodiment, the mounting frame <NUM> can also be supported by the two vertical plates <NUM> arranged at intervals. Further, the differential drive device <NUM> also includes a connecting shaft <NUM>. The two vertical plates <NUM> and the differential drive unit <NUM> are connected by the connecting shaft <NUM>, and the central axis of the connecting shaft <NUM> coincides with the transverse axis. Specifically, a middle of the connecting shaft <NUM> passes through the differential drive unit <NUM>, and two ends of the connecting shaft <NUM> correspondingly pass through the two vertical plates <NUM>. Thus, the differential drive unit <NUM> is hinged to the support body <NUM>, so that the differential drive unit <NUM> can swing around the transverse axis relative to the support body <NUM>.

Optionally, the differential drive device <NUM> further includes a first rolling member <NUM>, and the first rolling member <NUM> is arranged between the differential drive unit <NUM> and the outer cover <NUM> or between the support <NUM> and the outer cover <NUM>. The first rolling member <NUM> is used to enable the differential drive unit <NUM> to rotate around the longitudinal axis of the receptacle cavity, and is beneficial to ensure smooth and stable rotation of the differential drive device.

Optionally, there are a plurality of the first rolling members <NUM>, and the plurality of the first rolling members <NUM> are arranged at intervals from each other, thereby facilitating a stable rotation relationship between the differential drive unit <NUM> and the mounting frame <NUM>. Further, the first rolling member <NUM> may be a ball, a roller or a bearing, etc..

Optionally, as shown in <FIG>, when the support <NUM> is a horizontal support plate, the first rolling member <NUM> may be arranged both on the differential drive unit <NUM> and the horizontal support plate. The rotation of the differential drive unit <NUM> around the longitudinal axis of the receptacle cavity can be realized by the rolling of the first rolling member <NUM> on the inner wall of the outer cover <NUM>.

As shown in <FIG>, when the support <NUM> adopts two vertical plates <NUM>, the first rolling member <NUM> can be arranged on the differential drive unit <NUM> or the vertical plate <NUM>, wherein since the differential drive unit <NUM> is arranged between the two vertical plates <NUM>, in order to reduce the possibility of mutual interference between the components, it is a better way to arrange the first rolling member <NUM> on the vertical plate <NUM>.

Optionally, the differential drive device <NUM> further includes a plurality of second rolling members <NUM> arranged on the support body <NUM>, and the support body <NUM> supports the top plate <NUM> through the plurality of second rolling members <NUM>. As a result, the weight of the vehicle body of the AGV is mainly transmitted to the support body <NUM> through the second rolling member <NUM>, so that the first rolling member <NUM> does not bear the weight of the vehicle body, thereby preventing the first rolling member <NUM> from being deformed or even damaged.

Further, the second rolling member <NUM> may be a ball, a roller or a bearing, etc..

Optionally, as shown in <FIG>, when the support body <NUM> is a horizontal support plate, the second rolling member <NUM> can be arranged at the corner of the horizontal support plate. Specifically, a protrusion can be formed at the corner of the horizontal support plate, and then the second rolling member <NUM> can be installed on the protrusion. As a result, the second rolling member <NUM> is less likely to interfere with other structures. In addition, if the second rolling member <NUM> is a roller or bearing, the rotating shaft thereof can be arranged parallel to the plate surface of the horizontal support plate, so that the second rolling member <NUM> can provide a more stable support for the top plate <NUM>.

As shown in <FIG>, when the support <NUM> adopts two vertical plates <NUM>, the second rolling member <NUM> can be arranged on the outer side of the vertical plate <NUM> (a side facing away from the differential drive unit <NUM>). In addition, if the second rolling member <NUM> is a roller or bearing, the rotating shaft thereof can be arranged parallel to the plate surface of the horizontal support plate, so that the second rolling member <NUM> can provide a more stable support for the top plate <NUM>.

In addition, the rotating shaft of the second rolling member <NUM> and the connecting shaft <NUM> can also be integrated as an integral part, that is, the end of the connecting shaft <NUM> can be extended, and the second rolling member <NUM> can be installed on the end of the connecting shaft <NUM>, so that the number of parts can be reduced and the cost can be saved.

Optionally, the differential drive unit <NUM> includes a driving wheel <NUM> and a power unit <NUM> connected to the driving wheel <NUM>, wherein the power unit <NUM> provides power for the rotation of the driving wheel <NUM>, and the power unit <NUM> is hinged to the support body <NUM>.

Optionally, an axle of the driving wheel <NUM> is perpendicular to the transverse axis. In this case, when the power unit <NUM> swings around the transverse axis, the height of the driving wheel <NUM> changes most significant, so that the driving wheel <NUM> can adapt to the height change of the road surface to the greatest extent.

Optionally, the number of the driving wheels <NUM> is two, and the forward direction of the AGV can be controlled by implementing different control methods for the two driving wheels <NUM>. For example, when the two driving wheels <NUM> rotate in the positive direction at the same speed, the AGV can be driven forward; when the two driving wheels <NUM> rotate in the opposite directions at the same speed, the AGV can be driven backward; and when the two driving wheels <NUM> rotate forward at different speeds or when one of the two driving wheels <NUM> rotates forward and the other rotates backward, the AGV can be driven to turn.

It can be understood that a supporting wheel may be additionally provided at the bottom of the AGV to cooperate with the differential drive device <NUM> to support the AGV and make the AGV moving on the ground. Alternatively, a plurality of differential drive devices <NUM> can also be arranged at the bottom of the AGV to make the AGV obtaining stable support.

Optionally, the power unit <NUM> includes a motor and a reduction mechanism (not shown in the figure). The motor is connected to the driving wheel <NUM> through a reduction mechanism (for example, a gear reduction mechanism, a planetary gear reduction mechanism, etc.), thereby reducing the output speed of the motor and increasing the output torque of the motor.

Optionally, the number of the motor is one. At this time, the reduction mechanism can choose a differential reducer. As a result, the two driving wheels <NUM> can be controlled by one motor to rotate in the same direction at the same speed, in the same direction at different speeds, or to rotate in opposite directions, so that the driving wheels <NUM> can drive the AGV forward, backward and turn.

Optionally, the number of the motors and the reduction mechanisms can also be two respectively, that is, each of the motors is connected to one driving wheel <NUM> through one reduction mechanism. As a result, the corresponding driving wheels <NUM> are controlled by different motors, so as to achieve that the two driving wheels <NUM> rotate in the same direction at the same speed, in the same direction at different speeds, or in the opposite directions to each other, and the like.

Optionally, a ring-shaped limiting slot is formed on the side wall of the receptacle cavity (not shown in the drawings). The end of the connecting shaft <NUM> extends out of the differential drive unit <NUM> and is arranged in the limiting slot. As a result, it can be ensured that the connecting shaft <NUM> is always in a horizontal direction, so that the support body <NUM> can form an effective and stable support for the mounting frame <NUM>.

An embodiment of the present application also provides an AGV which includes the differential drive device in any of the embodiments described above.

Claim 1:
A differential drive device, wherein
the device comprises a differential drive unit (<NUM>), a top plate (<NUM>) and an outer cover (<NUM>), wherein the top plate (<NUM>) is installed on a top end of the outer cover (<NUM>), the differential drive unit (<NUM>) is located in the outer cover (<NUM>) at a lower side of the top plate (<NUM>), the top plate (<NUM>) is supported above the differential drive unit (<NUM>), an inner side wall of the outer cover (<NUM>) is circular-shaped;
characterized in that
a first rolling member (<NUM>) is provided on a side of the differential drive unit (<NUM>), the first rolling member (<NUM>) is in rolling connection with the lower side of the top plate (<NUM>).