Patent Description:
Currently, a steerable drive mechanism generally uses an encoder as a detection functional component to obtain steering information of the steerable drive mechanism, the encoder converts the steering information into an electrical signal, and inputs the electrical signal to a controller of a transport vehicle. The controller then issues a correction instruction to a motor based on specific operating conditions to achieve closed-loop control of the steerable drive mechanism.

<CIT> discloses an arrangement for determining absolute steering angles in a steerable drive device of industrial truck. The arrangement has a distance sensor for determining steering angles. Distance between the distance sensor and a cam track for determination of the steering angles is determined independence of the steering angles. The distance sensor is fixed at a frame plate of a vehicle frame. The distance to the distance sensor is changed along the cam track related to a steering axle in an axial direction or in a radial direction. A position sensor is assigned to another cam track.

The invention is defined by a steerable drive mechanism and a transport vehicle according to the independent claims.

In one aspect, a steerable drive mechanism is provided in the present closure. The steerable drive mechanism includes an outer bracket, an inner bracket, one or more traveling wheels, and a detection assembly, the inner bracket being rotatably disposed in the outer bracket.

The detection assembly includes a positioning element and a distance measuring element; in the positioning element and the distance measuring element, one is disposed on a peripheral outer wall of the inner bracket, and other is disposed on the outer bracket; the distance measuring element obtains relative movement information between the distance measuring element and the positioning element, to detect angular information of rotation of the inner bracket relative to the outer bracket.

In another aspect, a transport vehicle is provided in the present disclosure. The transport vehicle includes the above steerable drive mechanism.

The technical solutions adopted in the present disclosure can achieve the following beneficial effects:.

In the steerable drive mechanism disclosed in the present disclosure, the detection assembly includes a positioning element and a distance measuring element. Based on the cooperative use of the positioning element and the distance measuring element, the angular information of the rotation of the inner bracket relative to the outer bracket can be detected, and in turn, the rotation information of the traveling wheel can be obtained; meanwhile, in the positioning element and the distance measuring element, one is disposed on the peripheral outer wall of the inner bracket, and the other is disposed on the outer bracket. In this case, it is undoubtedly possible to avoid the detection assembly occupying excessive space in a height direction of the steerable drive mechanism, and achieve the object of reducing the whole size of the steerable drive mechanism.

Compared to the related art in which the encoder is stacked with the drive motor in the height direction of the steerable drive mechanism, the steerable drive mechanism disclosed in the present disclosure is based on the coordination of the positioning element and the distance measuring element, and can provide sufficient installation space for the drive assembly without increasing the whole size of the steerable drive mechanism, so that high-power type of drive assemblies may be selected, thereby improving the whole dynamic load capacity of the transport vehicle.

The drawings described herein are used to provide a further understanding of the present disclosure and constitute a part of the present disclosure. The schematic embodiments of the present disclosure and the description thereof are used to explain the present disclosure, and do not constitute an improper limitation on the present disclosure. In the accompanying drawings:.

The technical solutions of the present disclosure will be clearly and completely described below in conjunction with the specific embodiments of the present disclosure and the accompanying drawings in order to make the purpose, technical solutions and advantages of the present disclosure clearer. However, the described implementations are only a part, but not all, of the implementations of the present disclosure.

Steerable drive mechanisms have both driving and steering control functions. They may be divided into differential drive mechanisms and helm drive mechanisms/steering wheel drive mechanisms. Steerable drive mechanisms may be used to drive mechanical structures such as transport vehicles to achieve forward and backward straight movement or steering movement.

Two wheels of the differential drive mechanism are installed on a same axis, and speeds of the two wheels are controlled by two motion motors respectively, and the differential drive mechanism travels in a preset direction. In a case where the two wheels rotate at a same speed and in a same direction, the differential drive mechanism may travel in a straight line. In a case where the two wheels rotate at the same speed and in opposite directions, the differential drive mechanism rotates on the spot. In a case where the two wheels rotate at a differential speed, the differential drive mechanism may turn in an arc.

The helm drive mechanism has both driving and steering control functions, which are independently controlled by two motors. A drive motor provides driving force for the wheels, a steering motor controls rotation of the wheels, and the helm drive mechanism may travel and turn simultaneously. In addition to in-place turning and arc turning, the helm drive mechanism may also achieve left and right translation, and oblique translation. Common types of helm drive mechanisms include single helm drive and dual helm drive.

In the related arts, an encoder has a certain volume, and is generally stacked with the drive motor, thereby causing the whole size of the steerable drive mechanism in a height direction to be too large; in a case where the whole size of the steerable drive mechanism is ensured to be constant, installation space of the drive motor will be compressed, thus it is forced to only adopt a low-power type drive motor, thereby limiting the whole power load capacity of the transport vehicle.

In a case where the encoder is a hollow encoder, the interior of the hollow encoder is hollow, and its hollow space is also used to accommodate other structures, such as a cable for the drive motor, thus the above problem is even more serious.

The technical solutions disclosed by the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

Referring to <FIG>, the embodiments of the present disclosure discloses a steerable drive mechanism, which includes an outer bracket <NUM>, an inner bracket <NUM>, a traveling wheel <NUM>, and a detection assembly <NUM>. In some embodiments, the types of steerable drive mechanisms are not limited, for example, they may be steerable drive mechanisms for transport vehicles or mobile robots. The following content takes a steerable drive mechanism on board a transport vehicle as an example.

The outer bracket <NUM> and the inner bracket <NUM> both are basic components of a steerable drive mechanism, and can play a supporting role as a foundation for mounting and support.

The steerable drive mechanism generally further includes a drive assembly <NUM>, which is a power component of the steerable drive mechanism. The traveling wheel <NUM> may be used in conjunction with the drive assembly <NUM>, and the drive assembly <NUM> is connected to the traveling wheel <NUM>, and the traveling wheel <NUM> is driven by the drive assembly <NUM>, so that the traveling wheel <NUM> is driven to move on a support surface. For example, the drive assembly <NUM> can drive the traveling wheel <NUM> to rotate, thereby enabling the traveling wheel <NUM> to move on the support surface. The drive assembly <NUM> can also drive the traveling wheel <NUM> to turn. The above operating principle is common knowledge in the art, and will not be described herein. In some embodiments, there are various types of support surfaces, such as floors, worktops, or logistics tracks.

The detection assembly <NUM> is a functional component of a steerable drive mechanism that can detect angular information of the rotation of the inner bracket <NUM> relative to the outer bracket <NUM>, thereby obtaining the steering information of the traveling wheel. It will be understood that when the steerable drive mechanism performs a steering action, it needs to obtain the steering information of the traveling wheel <NUM> through the detection assembly <NUM>, convert the steering information into an electrical signal, and transmit it to a controller of the transport vehicle. The controller then issues a correction instruction to the drive assembly <NUM> according to the specific operating condition, to adjust the steering angle of the traveling wheel <NUM>, and through the above operating process, the closed-loop control of the transport vehicle over the traveling wheel is completed.

In some embodiments, the drive assembly <NUM> may generally be provided in the inner bracket <NUM> to optimize the structural layout. In combination with the foregoing, the drive assembly <NUM> is connected with the traveling wheel <NUM> and drives the traveling wheel <NUM>. When the traveling wheel <NUM> turns, the traveling wheel <NUM> will bring the inner bracket <NUM> to rotate. Meanwhile, the inner bracket <NUM> is rotatably arranged in the outer bracket <NUM>, which means that the inner bracket <NUM> may have relative rotation relative to the outer bracket <NUM>. Therefore, when the inner bracket <NUM> rotates, there will be no interference between the inner bracket <NUM> and the outer bracket <NUM>.

In some embodiments, the inner bracket <NUM> may be rotationally fitted with the inner wall of the outer bracket <NUM> through the outer circumference of the inner bracket <NUM>. In some embodiments, the rotatable relationship between the two may be achieved through a clearance sliding fit. The inner bracket <NUM> may also be connected with the outer bracket <NUM> through other rotational fit relationships. The power source for the rotation of the inner bracket <NUM> relative to the outer bracket <NUM> is the indirect drive of the drive assembly <NUM>.

In some embodiments, the detection assembly <NUM> includes a positioning element <NUM> and a distance measuring element <NUM>. In the positioning element <NUM> and the distance measuring element <NUM>, one is disposed on a peripheral outer wall of the inner bracket <NUM>, and the other is disposed on the outer bracket <NUM>. That is, the positioning element <NUM> may be disposed on the peripheral outer wall of the inner bracket <NUM>, and the distance measuring element <NUM> may be correspondingly disposed on the outer bracket <NUM>, or the distance measuring element <NUM> may be disposed on the peripheral outer wall of the inner bracket <NUM>, and the positioning element <NUM> is correspondingly disposed on the outer bracket <NUM>. The embodiments do not limit the setting positions of the positioning element <NUM> and the distance measuring element <NUM>.

The distance measuring element <NUM> may obtain information about its relative movement with the positioning element <NUM>, to detect the angular information about the rotation of the inner bracket <NUM> relative to the outer bracket <NUM>. Since there is a relative rotation between the inner bracket <NUM> and the outer bracket <NUM>, during this process, there is also a relative rotation between the positioning element <NUM> and the distance measuring element <NUM>. The movement information of the positioning element <NUM> relative to the distance measuring element <NUM> may be processed by the controller inside the transport vehicle, to obtain the steering information of the traveling wheel <NUM>. The controller can then issue an instruction to control the traveling wheel <NUM> to turn to the desired direction/position, and completes accurate steering action.

As can be seen from the above description, in the steerable drive mechanism disclosed in the embodiments of the present disclosure, the detection assembly <NUM> includes a positioning element <NUM> and a distance measuring element <NUM>. Based on the cooperative use of the positioning element <NUM> and the distance measuring element <NUM>, the angular information of the rotation of the inner bracket relative to the outer bracket can be detected, thereby obtaining the steering information of the traveling wheel <NUM>; meanwhile, in the positioning element <NUM> and the distance measuring element <NUM>, one is disposed on the peripheral outer wall of the inner bracket <NUM>, and the other is disposed on the outer bracket <NUM>. In this case, it can be avoided that the detection assembly <NUM> occupies excessive space in the height direction of the steerable drive mechanism, and the object of reducing the whole size of the steerable drive mechanism can be achieved.

Compared to related arts in which the encoder is stacked with the drive motor in the height direction of the steerable drive mechanism, the steerable drive mechanism disclosed in the embodiments of the present disclosure is based on the cooperative arrangement of the positioning element <NUM> and the distance measuring element <NUM>, thereby providing sufficient installation space for the drive assembly <NUM> without increasing the whole size of the steerable drive mechanism, so that a high-power type drive assembly <NUM> may be adopted, and the whole dynamic load capacity of the transport vehicle is improved.

In some embodiments, there are various types of detection assemblies <NUM>. For example, the positioning element <NUM> is a magnet, and the distance measuring element <NUM> is a Hall device. When the inner bracket <NUM> rotates relative to the outer bracket <NUM>, relative movement occurs between the magnet and the Hall device. The Hall device may obtain the movement information of the magnet by detecting the intensity change of the magnetic field generated by the magnet, and the controller inside the transport vehicle calculates the steering information of the traveling wheel <NUM> based on the movement information.

In some embodiments, the detection assembly <NUM> may be a magnetic grid ruler, the positioning element <NUM> may be a scale magnetic grid, and the distance measuring element <NUM> may be a magnetic grid reader. It will be understood that the magnetic grid reader and the scale magnetic grid are generally induced to each other in a non-contact manner. Magnetic poles on the scale magnetic grid generate magnetic fields with different directions. The magnetic grid reader senses changes in the magnetic field during moving along the scale magnetic grid, converts the magnetic field change into an analog signal or a digital signal, and outputs the analog signal or the digital signal, that is, the magnetization signal read on the scale magnetic grid is converted into an electrical signal and transmitted it to the detection assembly to achieve displacement measurement or position positioning.

The scale magnetic grid and the magnetic grid reader change relative positions with the inner bracket <NUM> and the outer bracket <NUM>, respectively. The magnetic grid reader may move on the scale magnetic grid to obtain relative movement information between the two, and the controller inside the transport vehicle calculates the steering information of the traveling wheel <NUM> based on the movement information.

The detection assembly <NUM> may also be other detection structures, as long as the steering information of the traveling wheel <NUM> can be detected through reasonable arrangement of the structure, for example, the detection assembly <NUM> is a combination of a magnetic device and a Hall device.

In some embodiments, there is no limitation on the arrangement manner of the magnetic grid ruler. In an optional solution, the circumferential outer wall of the inner bracket <NUM> may be provided with an arc mounting surface, the scale magnetic grid is disposed along the arc mounting surface, and the magnetic grid reader is disposed on the outer bracket <NUM>. In this way, due to the relative movement between the inner bracket and the outer bracket, the magnetic grid reader moves on the scale magnetic grid along the arc mounting surface, and its movement trajectory tends to perform a circular rotational motion based on the arc mounting surface, thereby obtaining more accurate steering information of the traveling wheel <NUM>.

The scale magnetic grid may also be disposed on the outer bracket <NUM>, and the magnetic grid reader is disposed on the peripheral outer wall of the inner bracket <NUM>. In this case, the outer bracket <NUM> may be correspondingly provided with the arc mounting surface for installing the scale magnetic grid.

It will be understood that the scale magnetic grid has a certain length/size and a small thickness. Therefore, in the above embodiments, the scale magnetic grid may be installed using the circumferential outer wall of the inner bracket <NUM>, and only occupies a small space of the circumferential side of the inner bracket <NUM>, thereby avoiding occupying a large space in the height direction of the steerable drive mechanism, so that it is possible to provide greater installation space for the drive assembly <NUM> without increasing the whole size of the steerable drive mechanism, so as to facilitate the use of high-power type drive assemblies.

In some embodiments, the detection assembly <NUM> may be a grating ruler, the positioning element <NUM> may be a scale grating, and the distance measuring element <NUM> may be a grating reader. It will be noted that a grating ruler is a photoelectric detection element made by using the transmission and diffraction phenomena of light. An indicator grating is provided in the grating reader. When the relative position between the scale grating and the grating reader changes with the inner bracket <NUM> and the outer bracket <NUM>, the indicator grating moves on the scale grating, thereby obtaining relative movement information between the two, and the controller inside the transport vehicle calculates the steering information of the traveling wheel <NUM> based on the movement information.

The arrangement manner of the magnetic grid ruler in the above embodiments may also be adopted for the grating ruler.

To optimize the structural layout of the steerable drive mechanism and optimize space utilization, in the optional scheme, the outer bracket <NUM> may be provided with a first installation space <NUM>, which is opposite to the scale magnetic grid, and the magnetic grid reader is disposed in the first installation space <NUM>.

Through the first installation space <NUM>, the magnetic grid reader may be embedded in the outer bracket <NUM>, thereby avoiding the magnetic grid reader being installed between the outer bracket <NUM> and the inner bracket <NUM>, reducing a gap between the outer bracket <NUM> and the inner bracket <NUM>, and improving the structural compactness and space utilization of the steerable drive mechanism; meanwhile, the first installation space <NUM> is opposite to the scale magnetic grid, and the magnetic grid reader disposed in the first installation space <NUM> may obtain displacement information from the scale magnetic grid, thereby ensuring the normal operation of the magnetic grid ruler.

In some embodiments, there are various types of the first installation space <NUM>, such as installation slots, or installation through-holes.

The outer bracket <NUM> may have various structural forms, and the inner bracket <NUM> is rotationally matched with the outer bracket <NUM> through a rotating shaft. In some embodiments, the outer bracket <NUM> may have a first accommodation space <NUM> and an opening. The opening communicates with the first accommodation space <NUM>. The inner bracket <NUM> and the traveling wheel <NUM> are both disposed in the first accommodation space <NUM>, and the traveling wheel <NUM> is exposed out of the outer bracket <NUM> through the opening to move on the support surface.

It will be understood that in the above embodiments, since the inner bracket <NUM> and the traveling wheel <NUM> are both located in the first accommodation space <NUM>, that is, the outer bracket <NUM> wraps around the inner bracket <NUM> and the traveling wheel <NUM>, so that the outer bracket <NUM> can play a protective role for the inner bracket <NUM> and the traveling wheel <NUM>, preventing damage to the inner bracket <NUM>, the drive assembly <NUM> and the traveling wheel <NUM> that are provided in the inner bracket <NUM>. The opening is generally disposed on a side of the outer bracket <NUM> facing the support surface, so that the traveling wheel <NUM> may extend outside of the outer bracket <NUM> through the opening and contact the support surface to move on the support surface. It will be understood that if foreign matters fall from the top of the outer bracket <NUM> into the inner bracket and/or the outer bracket, the foreign matters will affect the normal operation of the steerable drive mechanism. To avoid the above problem, a cover may be installed on the top of the outer bracket <NUM>, and the cover may be fixed to the top of the outer bracket <NUM> by screws or welding. In addition, to prevent the inner bracket from completely detaching from the opening, the size of the opening is smaller than the inner bracket. For example, the inner wall of the outer bracket is provided with a position-limiting step.

The inner bracket <NUM> may be provided with rolling bodies <NUM> along the peripheral outer wall of the inner bracket <NUM>, and the inner bracket <NUM> rotatably engages with the outer bracket <NUM> through the rolling bodies <NUM>. It will be understood that the inner bracket <NUM>, the outer bracket <NUM>, and the rolling bodies <NUM> can form a rolling bearing structure, thereby improving the smoothness of rotation between the inner bracket <NUM> and the outer bracket <NUM>, to achieve higher rotational efficiency.

The type of rolling bodies <NUM> is not limited. As shown in <FIG>, the rolling bodies <NUM> may be selected as side rollers, however it may also be of other types, such as balls. The number of rolling bodies <NUM> is also not limited and may be one or more.

In addition, the top of the inner bracket is provided with two or more grooves, in which second rolling bodies are disposed, and the second rolling bodies partially protrudes out of the grooves, enabling the inner bracket to roll against the cover installed on the top of the outer bracket, further improving the rotational smoothness between the inner bracket <NUM> and the outer bracket <NUM>, to achieve higher rotational efficiency. The type of the second rolling bodies is not limited and may be rollers, balls, or other suitable structures.

In some embodiments, when the traveling wheel <NUM> is in contact with the support surface, the inner bracket <NUM> abuts against the cover installed on the top of the outer bracket through second rolling bodies, and there is a gap between the lower surface of the side of the inner bracket <NUM> and the flange on the circumferential side of the opening in the outer bracket.

Generally, the inner bracket <NUM> is a circular rotating bracket. In this way, the rotation action of the inner bracket <NUM> is less likely to be interfered with by the outer bracket <NUM>, and the center of gravity of the inner bracket <NUM> is constant, and does not causes eccentric problems, so that the rotation efficiency is the highest; meanwhile, because the inner bracket <NUM> makes circular rotation movement, from the perspective of the configuration of the rotating structure, the circular rotating bracket is more convenient to be installed in the outer bracket <NUM>.

The embodiments do not limit the specific number of traveling wheels <NUM>, and there may be one traveling wheel <NUM>. In this case, to ensure that the traveling wheel <NUM> may achieve the steering function, the drive assembly <NUM> needs to include a steering motor that drives the traveling wheel <NUM> to achieve the steering action.

Alternatively, there may be two traveling wheels <NUM>. In this case, the drive assembly <NUM> may include two drive modules, each of which is connected to a traveling wheel <NUM> and drives the traveling wheel <NUM>. By driving the traveling wheels <NUM> through two drive modules respectively, differential speed control of the two traveling wheels <NUM> may be achieved. When the transport vehicle is used, the controller of the transport vehicle may control the two drive modules to indirectly control the rotational speeds of the two traveling wheels <NUM> to be different, that is, one traveling wheel <NUM> has a higher rotational speed and the other traveling wheel <NUM> has a lower rotational speed. In this case, the whole steerable drive mechanism will turn towards a side where the traveling wheel <NUM> with a lower rotational speed is disposed. For the helm drive mechanism, two drive modules may also be used to drive the traveling wheel <NUM> to operate and steer appropriately according to a preset angle, thereby cooperating to achieve the steering movement of the helm drive mechanism.

To further optimize the structural layout of the steerable drive mechanism and improve the structural compactness and space utilization of the steerable drive mechanism, in optional solutions, the inner bracket <NUM> may be provided with a second installation space <NUM>, and the drive assembly <NUM> may be provided within the second installation space <NUM>. The inner bracket <NUM> may also be provided with a second accommodation space <NUM>, which is communicated with the second installation space <NUM>, and the traveling wheel <NUM> is disposed in the second accommodation space <NUM>.

It will be understood that based on the second installation space <NUM> and the second accommodation space <NUM>, the drive assembly <NUM> and the traveling wheel <NUM> both can be embedded in the inner bracket <NUM>, thereby avoiding the drive assembly <NUM> and the traveling wheel <NUM> disposing in the gap between the outer bracket <NUM> and the inner bracket <NUM>, and reducing the gap between the outer bracket <NUM> and the inner bracket <NUM>, that is, the outer bracket <NUM> and the inner bracket <NUM> may be disposed closer, Thus the structural compactness and space utilization of the steerable drive mechanism is further improved.

As shown in <FIG>, in a case where there are two traveling wheels <NUM>, the two drive modules may be integrated into a modular drive assembly <NUM>, which is more convenient to be embedded in the second installation space <NUM>. The two traveling wheels <NUM> may be respectively disposed on opposite sides of the drive assembly <NUM>, so that the traveling wheels <NUM> are more evenly distributed to avoid interference between the two traveling wheels <NUM>. However, in this case, the second accommodation space <NUM> needs to be two to accommodate the two traveling wheels <NUM>.

It will be noted that the structure (including the first accommodation space <NUM>, the opening, and the second accommodation space <NUM>) for accommodating the traveling wheel <NUM> needs to be able to ensure that the traveling wheel <NUM> is not subject to interference during rotation, steering, and other actions.

Please refer to <FIG>, which shows another steerable drive mechanism, in which the inner bracket <NUM> may be provided with a notch region <NUM> that may be used to accommodate smaller structures within the steerable drive mechanism, such as the power supply cable of the drive assembly <NUM>. The number and location of the notch region <NUM> are not limited and may be determined based on the specific operating conditions inside the steerable drive mechanism.

Based on the above steerable drive mechanism, the embodiments of the present disclosure further disclose a transport vehicle, which includes the above steerable drive mechanism. The transport vehicle referred to in the embodiments of the present disclosure may be an automated guided vehicle (AGV), a rail guided vehicle (RGV), an intelligent guided vehicle (IGV), etc. The embodiments of the present disclosure do not limit the types of transport vehicles.

Generally, the outer bracket <NUM> of the steerable drive mechanism is the vehicle body frame of the transport vehicle. In this case, the inner bracket <NUM> is directly rotatably engaged with the vehicle body frame. In this way, because of the omission of the outer bracket <NUM> structure in the steerable drive mechanism, the whole volume of the steerable drive mechanism may be reduced, thereby improving the space utilization rate inside the transport vehicle. Alternatively, the outer bracket <NUM> of the steerable drive mechanism and the vehicle body frame of the transport vehicle may also be separate components. In this case, the steerable drive mechanism is an independent module, and based on modular design, it is possible to optimize the ease of disassembly and mounting of the steerable drive mechanism and is more conducive to troubleshooting.

Claim 1:
A steerable drive mechanism, comprising an outer bracket (<NUM>), an inner bracket (<NUM>), one or more traveling wheels (<NUM>), and a detection assembly (<NUM>), the inner bracket (<NUM>) being rotatably disposed in the outer bracket (<NUM>); wherein
the detection assembly (<NUM>) comprises a positioning element (<NUM>) and a distance measuring element (<NUM>);
characterized in that, in the positioning element (<NUM>) and the distance measuring element (<NUM>), one is disposed on a peripheral outer wall of the inner bracket (<NUM>), and other is disposed on the outer bracket (<NUM>);
the distance measuring element (<NUM>) obtains relative movement information between the distance measuring element (<NUM>) and the positioning element (<NUM>), to detect angular information of rotation of the inner bracket (<NUM>) relative to the outer bracket (<NUM>).