A hydraulic heavy-duty robot joint device with a torque of 200 kN·m

Abstract

This invention discloses a heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer, belonging to the field of heavy-duty robot automation equipment technology. The device consists of a low-speed, high-torque hydraulic motor, a two-stage cascaded cycloidal pinwheel reducer unit, an output unit, a sensing unit, and an integrated sealed housing. It uses the hydraulic motor as the power input source, achieving multi-stage speed reduction and torque amplification through a two-stage high-ratio cycloidal pinwheel reducer, stably outputting a massive 200kN·m torque. Simultaneously, it incorporates an angle encoder, torque sensor, or six-dimensional force sensor to form a full-dimensional sensing system, synchronously collecting joint position, rotational speed, load torque, and multi-dimensional force information to construct a high-precision force-position dual closed-loop control system. This invention overcomes the technical bottlenecks of traditional electromechanical heavy-duty joints, such as insufficient torque, large size, poor impact resistance, low sensing accuracy, and high cost. Relying on the advantages of hydraulic drive's high overload and self-locking capabilities, as well as the high rigidity and impact resistance of cycloidal pinwheel transmission, it has the advantages of compact structure, high power density, stable operation, strong environmental adaptability, and outstanding cost performance. It can be widely used in ultra-high torque operation scenarios such as heavy-duty industrial robotic arms, special engineering machinery, large rotary work platforms, and automated heavy-duty assembly equipment.

Description

Technical Field

[0001] This invention belongs to the technical field of heavy-duty industrial robots, special engineering machinery and large-scale automated rotary equipment. Specifically, it relates to a 200kN·m heavy-duty robot joint device that uses a hydraulic motor as a power source, a two-stage cycloidal pinwheel reducer to achieve multi-stage torque amplification, and is equipped with an angle encoder, torque sensor or six-dimensional force sensor to achieve high-precision force and position sensing. Background Technology

[0002] Currently, most heavy-duty robot rotary joints adopt an electromechanical integrated drive solution with servo motors and reducers. This solution has many technical shortcomings under heavy-duty conditions with ultra-high torque of 200kN·m, making it difficult to meet the demanding operational requirements. First, the electromechanical drive system is bulky, heavy, and has low power density, making it impossible to achieve a compact integrated design for robot joints and limiting the development of lightweight and miniaturized heavy-duty robots. Second, the supporting precision reducers have weak impact resistance and low short-term overload capacity, making them prone to tooth surface wear and structural damage under frequent start-stop, impact load, and continuous heavy-load conditions, resulting in a short equipment lifespan. Third, existing ultra-high torque precision reducers are highly dependent on imports, resulting in high procurement costs and long supply cycles, significantly increasing the manufacturing cost and mass production difficulty of heavy-duty robots. Fourth, pure electromechanical drive joints lack natural self-locking function, requiring the addition of electromagnetic braking devices, which not only increases the complexity of the joint structure and the number of potential failure points but also occupies limited integration space. Fifth, traditional electromechanical joints often estimate output torque indirectly through motor current, resulting in poor detection accuracy and large error fluctuations, and the adaptation of external high-precision sensing equipment is difficult and costly. Hydraulic motors possess outstanding advantages such as high power density, strong overload capacity, good operational buffering, and pressure-holding self-locking capability, making them suitable for heavy-duty and impact-type operating scenarios. Cycloidal pinwheel reducers feature multi-tooth synchronous meshing, high structural rigidity, excellent impact resistance, a wide transmission ratio range, and compact integrated size, making them the preferred transmission structure for high-torque reduction and torque amplification. Currently, the industry lacks integrated heavy-duty robot joints that deeply integrate low-speed, high-torque hydraulic motors with a two-stage cycloidal pinwheel reducer mechanism, while also incorporating a complete force and position sensing system. This integration enables stable output of ultra-high torque up to 200 kN·m and supports high-precision force and position closed-loop control, hindering the large-scale application of heavy-duty robots and special engineering machinery. Summary of the Invention

[0003] 3.1 Purpose of the Invention To address the shortcomings of existing electromechanical heavy-duty robot joints, such as insufficient joint torque, bulky structure, poor impact resistance, low sensing accuracy, and high manufacturing cost, as well as the lack of standardized two-stage reduction and torque amplification structures and high-precision force-position coordination control capabilities in existing hydraulic joints, this invention provides a heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer. This invention uses a low-speed, high-torque hydraulic motor as the power source, combined with a two-stage series cycloidal pinwheel reducer to achieve large-span torque amplification. It utilizes an angle encoder and a torque / six-dimensional force sensor to construct a full-dimensional sensing system, achieving high-precision position and force control closed-loop regulation. This solves the industry pain points of insufficient overall performance in existing heavy-duty joints and is suitable for various ultra-high torque heavy-duty operation scenarios. 3.2 Technical Solution To achieve the above objectives, the present invention adopts the following technical solution: a heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer, comprising a drive unit, a two-stage cycloidal pinwheel reducer unit, an output unit, a sensing unit, a joint housing, and a support bearing. The drive unit is a low-speed, high-torque hydraulic motor, which can be either a cycloidal hydraulic motor or a radial piston hydraulic motor. As the sole power input source for the joint, it has the working characteristics of high torque, low speed, and overload resistance, and can be adapted to heavy-duty continuous operation conditions. The two-stage cycloidal pinwheel reduction unit consists of a first-stage cycloidal pinwheel reducer and a second-stage cycloidal pinwheel reducer rigidly connected in series. The two reducers are coaxially connected and synchronously transmitted. Each stage of the cycloidal pinwheel reducer is equipped with a pin tooth housing, cycloidal wheel, eccentric input shaft, ring pin tooth, and disc output mechanism. High rigidity and low loss transmission are achieved by relying on multi-tooth synchronous meshing. The two reducers work together to form a wide-range total transmission ratio of 100 to 600, realizing step-by-step power reduction and step-by-step torque amplification. The output unit is fixedly connected to the power output end of the second-stage cycloidal pinwheel reducer. It adopts a flange-type integrated structure and can stably output a super-large torque of 200kN·m as the drive end for the joint to drive external loads. The sensing unit includes two types of sensing devices: an angle encoder and a torque sensor or a six-dimensional force sensor. These two types of devices work together to complete the full-dimensional monitoring of the joint's operating status. The angle encoder is responsible for collecting real-time rotation angle and speed position signals of the joint, while the torque sensor or six-dimensional force sensor is responsible for collecting real-time torque and multi-dimensional load force information at the joint's output end, providing accurate data support for closed-loop control. The joint output end is equipped with a heavy-duty crossed roller bearing, which can simultaneously withstand radial load, axial load and overturning moment, effectively improving the overall rigidity and load-bearing stability of the joint, and eliminating structural deformation and transmission deviation under heavy load conditions. The joint housing is an integrated sealed structure that encapsulates the hydraulic motor, two-stage cycloidal pinwheel reducer, sensing unit, and support bearing. The housing has a protection rating of no less than IP65, which can effectively isolate dust, oil, and moisture interference, making it suitable for harsh working environments. 3.3 Working Principle During operation, the low-speed, high-torque hydraulic motor outputs initial rotational power. This power is sequentially input to the first-stage and second-stage cycloidal pinwheel reducers arranged in series. Through these two stages of high-ratio reduction, the speed is gradually reduced and the torque amplified, ultimately achieving a stable output of 200 kN·m of ultra-large drive torque at the output flange, meeting the requirements of ultra-heavy-duty operations. During operation, the speed-angle encoder collects the angular displacement and rotational parameters of the joints in real time, while the torque sensor or six-dimensional force sensor collects the load torque and multi-dimensional force state in real time. All sensing signals are synchronously transmitted to the hydraulic control system. Based on the collected data, the control system constructs a position and force / torque dual closed-loop control logic, dynamically adjusting the hydraulic motor's oil supply parameters to achieve high-precision force-position coordinated control of the joints. Simultaneously, the hydraulic system has a power-off and shutdown pressure-holding self-locking function, enabling heavy-load hovering and locking to prevent load slippage and improve equipment operation safety. 3.4 Beneficial Effects Compared with the prior art, the present invention has the following significant advantages: (1) Stable output of ultra-large torque and strong adaptability to heavy load. Through the combination design of hydraulic motor and two-stage cycloidal pinwheel reduction mechanism, relying on the high-multiple torque amplification structure, it can stably output ultra-large torque of 200kN·m, which fully meets the heavy-load operation requirements of ultra-heavy industrial robots and large rotating equipment. The torque output performance far exceeds that of traditional electromechanical drive joints. (2) High power density and compact structure with high integration. Hydraulic motors naturally have high power density characteristics. Combined with the miniaturization and high speed ratio of the two-stage cycloidal pinwheel reducer, the overall volume and weight are much smaller than the combination of a motor + imported RV reducer of the same torque level. This allows for compact joint integration and installation, making it suitable for narrow working spaces. (3) Excellent impact and overload resistance, and long service life. The hydraulic drive has flexible buffering characteristics, and the equipment has a high overload ratio, which can effectively buffer heavy impact loads; the multi-tooth synchronous meshing structure of the cycloidal pinwheel reducer can evenly distribute the load stress, and has outstanding impact and wear resistance, which greatly improves the running stability and service life of the joint under high-frequency heavy load and impact conditions. (4) Full-dimensional force and position perception, high control precision. Through the dual-sensing configuration of angle encoder and torque / six-dimensional force sensor, the joint position, speed, torque and multi-dimensional force information can be collected simultaneously and accurately to build a high-precision dual closed-loop control system, realize precise position control and flexible force control operation, and can be adapted to high-precision operation scenarios such as precision assembly, flexible grinding and heavy-duty docking. (5) It has its own hydraulic self-locking mechanism, which is safe and reliable. Relying on the pressure-holding and self-locking characteristics of the hydraulic system, it can achieve stable suspension and locking under heavy load without the need for an additional electromagnetic braking device in the power failure or shutdown state. This reduces the number of equipment failure points, reduces structural complexity, eliminates the risk of load slippage, and greatly improves operational safety. (6) High degree of localization and significant cost advantage. The core power, transmission and sensing components all use mature domestic components, without relying on imported precision reducers, which greatly reduces equipment procurement and maintenance costs, ensures stable supply, and is suitable for large-scale mass production and promotion. (7) Strong environmental adaptability and wide range of applicable scenarios. The integrated fully sealed shell structure has a protection level of IP65 and above, which can effectively resist dust, oil, water vapor and vibration interference, and can operate stably for a long time in various harsh operating scenarios such as industrial workshops, outdoors, mines, and ports. Attached Figure Description Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the transmission principle of the two-stage cycloidal pinwheel reducer of the present invention (the part numbers are consistent before and after). Figure 3 This is a block diagram of the sensing and control system principle of the present invention. Explanation of reference numerals in the attached diagram: 1-Hydraulic motor; 2-First-stage cycloidal pinwheel reducer; 3-Second-stage cycloidal pinwheel reducer; 4-Output flange; 5-Angle encoder; 6-Torque sensor / six-dimensional force sensor; 7-Joint housing; 8-Heavy-duty crossed roller bearing. Detailed Implementation

[0004] Example 1 (200kN·m standard heavy-duty joint example) A heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer includes a drive unit, a two-stage cycloidal pinwheel reducer unit, an output unit, a sensing unit, a joint housing, and a support bearing. The drive unit uses a cycloidal hydraulic motor with a rated input torque of 1200 N·m and a rated working pressure of 21 MPa, featuring low speed, high torque, and overload resistance. The two-stage cycloidal pinwheel reduction unit adopts a series integrated structure. The speed ratio of the first-stage cycloidal pinwheel reducer is set to 20, the speed ratio of the second-stage cycloidal pinwheel reducer is set to 20, and the total transmission ratio is 400. After conversion of transmission losses, the rated output torque of the joint can reach 216kN·m, which meets the heavy-load design requirements of 200kN·m. The sensing unit is equipped with an absolute angle encoder and a flange-type torque sensor. The angle encoder is installed at the input end of the hydraulic motor to collect joint angle and speed signals in real time; the torque sensor is integrated on the output flange end face to accurately collect real-time output torque data. The output end is equipped with a heavy-duty crossed roller bearing, which can withstand radial, axial and overturning loads in all directions, ensuring high rigidity operation of the joint; the joint housing adopts an integrated sealing structure with an IP65 protection level, which is suitable for conventional heavy-duty industrial operation scenarios. Example 2 (Example of a six-dimensional force-sensing flexible heavy-duty joint) The overall structure, power parameters, and transmission parameters of this embodiment are basically the same as those of Embodiment 1. The difference is that the flange-type torque sensor at the output end is replaced with a six-dimensional force sensor. The six-dimensional force sensor can accurately detect three-dimensional orthogonal forces and three-dimensional orthogonal moments in real time. It can identify the multi-dimensional force state of the load, collision interference, and contact force in real time, and can realize advanced operation functions such as robot compliant control, precision force-controlled assembly, intelligent collision detection, and flexible grinding. It is suitable for high-precision, high-flexibility heavy-duty operation scenarios.

Claims

1. A heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer, characterized in that, It includes a drive unit, a two-stage cycloidal pinwheel reduction unit, an output unit, a sensing unit, a joint housing, and a support bearing; The drive unit is a low-speed, high-torque hydraulic motor. The two-stage cycloidal pinwheel reduction unit is composed of a first-stage cycloidal pinwheel reducer and a second-stage cycloidal pinwheel reducer connected in series, with a total transmission ratio of 100 to 600, which is used to realize the step-by-step reduction and torque increase of power. The output unit is connected to the output end of the second-stage cycloidal pinwheel reducer, and the rated output torque is 200kN·m. The sensing unit includes an angle encoder and a torque sensor or a six-dimensional force sensor, used to synchronously collect information on joint position, rotational speed and load force. The hydraulic motor, two-stage cycloidal pinwheel reducer, output unit, and sensing unit are integrated and installed inside the joint housing, forming an integrated sealed heavy-duty robot joint structure.

2. The heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer as described in claim 1, characterized in that, The hydraulic motor is a cycloidal hydraulic motor or a radial piston hydraulic motor, with a rated input torque of 800 N·m to 2500 N·m and a rated working pressure of 16 MPa to 25 MPa.

3. The heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer as described in claim 1, characterized in that, Each stage of the cycloidal pinwheel reducer includes a pin tooth housing, a cycloidal wheel, an eccentric input shaft, an annular pin tooth, and a disc-type output mechanism. High rigidity and low loss reduction transmission are achieved through multi-tooth synchronous meshing.

4. The heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer as described in claim 1, characterized in that, The angle encoder is installed at the input end of the hydraulic motor or the output end of the joint to collect joint angular displacement and speed signals in real time, providing data support for position closed-loop control.

5. The heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer as described in claim 1, characterized in that, The torque sensor or six-dimensional force sensor is flange-integrated and installed at the end of the output unit to collect multi-dimensional load information such as joint output torque, three-dimensional force, and three-dimensional torque in real time.

6. The heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer as described in claim 1, characterized in that, The support bearing is a heavy-duty crossed roller bearing, assembled at the output end, which can simultaneously withstand radial force, axial force and overturning moment, thereby improving the overall rigidity and load-bearing stability of the joint.

7. The heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer as described in claim 1, characterized in that, The joint housing is an integrated, fully sealed structure with an overall protection level of no less than IP65, making it suitable for harsh working conditions such as dust, oil, and vibration.

8. The heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer as described in claim 1, characterized in that, The hydraulic motor and its hydraulic system have a power failure and shutdown pressure holding self-locking function, which can achieve heavy-load hovering and locking without the need for additional braking devices.

9. A heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer as described in claim 1, characterized in that, The angle encoder, together with the torque sensor or the six-dimensional force sensor, forms a position-force / torque dual closed-loop control system, enabling high-precision force-position coordinated control of the joint.

10. A heavy-duty robot joint device combining a 200kN·m hydraulic motor and a two-stage cycloidal pinwheel reducer as described in claim 1, characterized in that, This joint features a compact overall structure, high power density, and excellent impact resistance, making it suitable for heavy-duty industrial robots, special engineering machinery, and large-scale automated rotary mechanism equipment.

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