Joint module for a robot

Abstract

The invention relates to a joint module (10) for a robot (12) comprising • an input element (1) which is configured to be connected, at least indirectly, to a drive motor (15), • an output element (2) which is arranged coaxially to the input element (1) and is connected to the input element (1) in a drive-effective manner, • a fluid-tight sealed channel (3) formed between the inlet element (1) and the outlet element (2) for receiving a hydraulic fluid, wherein the channel (3) has at least one variable flow cross-section, • a shaped element (4) which is designed to transmit a drive power between the input element (1) and the output element (2) and to displace the hydraulic fluid in the channel (3), wherein a damping of the movement of the shaped element (4) in the channel (3) is adjustable by changing the flow cross-section, and • an adjusting device (5) for adjusting the flow cross-section.

Description

[0001] The invention relates to a joint module for a robot. Furthermore, the invention also relates to a drive unit for a robot comprising a drive motor and such a joint module. The invention also relates to a robot comprising such a joint module. In particular, the robot is configured as a cobot or humanoid robot.

[0002] A cobot, short for "collaborative robot," is a robot designed to work closely with humans. Unlike industrial robots, which often operate in enclosed spaces and require strict safety measures, cobots are designed to work safely and efficiently alongside human workers. Cobots are used in numerous industries, such as automotive, pharmaceuticals, and food production. They assist human workers with repetitive or ergonomically demanding tasks, thereby improving working conditions and increasing production quality. A humanoid robot is a robot that has human-like characteristics and appearance. Humanoid robots are trained to mimic human shape, movements, and even behaviors.

[0003] For example, DE 10 2018 008 378 A1 discloses an elastic joint with a drive, an elastic mechanism, and an output. The elastic mechanism comprises a cam mechanism and a lever mechanism. The drive is connected to the cam mechanism, wherein the torque can be varied non-linearly by rotating a cam in conjunction with at least one spring element. The cam is connected to the lever mechanism, wherein a first lever arm of a lever is rotatably connected to the cam outside its center point, wherein a second lever arm of the lever is connected to the output, and the pivot of the lever is coupled to an adjustment mechanism for changing the position of the pivot and thus the stiffness.

[0004] DE 10 2019 129 847 A1 describes a coupling device for a robot joint with two robot arm segments. A rotor is connected to the first robot arm segment and a stator is non-rotatably connected to the second robot arm segment.

[0005] Between the rotor and stator is a first working chamber, which is operated with a hydraulic fluid to set a torque and to rotate the robot arm segments relative to each other.

[0006] 2. Coupling device (1) according to claim 1, characterized in that at least one second working chamber (9) is located between the R

[0007] DE 10 2014 218 555 A1 describes a torque converter device with a hydrodynamic unit arranged in a housing. This unit comprises a pump impeller connected to a drive shaft on the drive side, a turbine impeller connectable to the output shaft, and a guide vane. The impellers form a fluid-filled circuit which is supplied by an external supply unit.

[0008] DE 10 2019 106 503 A1 describes a safety coupling with coaxial input and output shafts which can be connected by force-locking means by pressurizing a pressure chamber formed in the safety coupling.

[0009] DE 27 07 530 A1 describes a fluid-operated coupling arrangement for the detachable coupling of at least two elements.

[0010] US Patent 5,201,842 A describes a coupling with a pressure-mediated hub for transmitting torque between a shaft and a hub. The object of the invention is to develop an alternative joint module. In particular, the joint module should be compact and exhibit adjustable vibration behavior. This object is achieved by the subject matter of claim 1. Preferred embodiments are described in the dependent claims, the description, and the figures.

[0011] A joint module according to the invention for a robot comprises an input element which is configured to be at least indirectly connected to a drive motor, an output element which is arranged coaxially to the input element and is connected to the input element in a drive-effective manner, a channel formed between the input element and the output element and which is sealed in a fluid-tight manner for receiving a hydraulic fluid, wherein the channel has at least one variable flow cross-section, a forming element which is configured to transmit a drive power between the input element and the output element and to displace the hydraulic fluid in the channel, wherein a movement damping of the forming element in the channel is adjustable by changing the flow cross-section, and an adjusting device for adjusting the flow cross-section.

[0012] The input element is, for example, an input shaft, in particular a flanged shaft, which can rotate according to the drive motor. The drive motor can be designed as an electric machine and configured to supply drive power to the input element. The output element is, for example, designed as an output shaft, in particular a flanged shaft. For example, the input element is non-rotatably connected to a rotor shaft of the electric machine. For example, the joint module is integrated into the rotor shaft of the electric machine. For example, the input element is non-rotatably connected to a gearbox output shaft of a gearbox located downstream of the electric machine. For example, the joint module is integrated into the gearbox output shaft of the gearbox.

[0013] The hydraulic fluid, i.e., an incompressible fluid, in particular a liquid, and the forming element are arranged in the channel. When the forming element is moved within the channel, the hydraulic fluid is also moved, causing it to flow through the variable cross-section. Changing the cross-section determines the vibration behavior of the joint module. The adjusting device is provided for this purpose.

[0014] According to one embodiment, in a fully open state of the actuator, the flow cross-section is at its maximum, so that the flow cross-section causes essentially no damping of the movement of the forming element in the channel. Thus, in the fully open state of the actuator, the hydraulic fluid can flow through the maximum flow cross-section essentially unimpeded. According to another embodiment, in a fully closed state of the actuator, the flow cross-section is closed, so that the inlet element and the outlet element are rotationally fixed to each other via the hydraulic fluid in the channel. In other words, essentially no hydraulic fluid flows through the flow cross-section, with the forming element pressing on the hydraulic fluid in the first channel section in a first direction of rotation and pressing on the hydraulic fluid in the second channel section in a second direction of rotation.

[0015] Between the fully open state of the actuator, which results in a maximum flow cross-section, and the fully closed state, which completely blocks the flow cross-section, a multitude of states or positions of the actuator are possible, thus achieving different flow cross-sections. Each of these states or positions of the actuator results in a different flow cross-section and therefore a different damping of movement. The damping of movement can thus be variably adjusted via the actuator depending on the situation. For example, the adjustment of a joint position of the joint module can be carried out as quickly as possible and without overshoot, which is described by the aperiodic limiting case. Alternatively, the actuator can also adjust the flow cross-section in such a way that the adjustment of a joint position of the joint module is slow and involves overshoot.In particular, the movement damping is always set before the joint module is adjusted. The joint module is adjusted by supplying drive power to the input element.

[0016] According to one embodiment, the molded element is rotationally fixed to the outlet element, and the channel is formed as a recess in the inlet element. In particular, the channel is formed as a recess on the end face of the inlet element. Preferably, the channel is completely filled with the hydraulic fluid. For example, a first seal and a second seal are arranged between the inlet element and the outlet element to seal the channel fluid-tight. Preferably, the two seals are designed as sealing rings. In particular, each seal is arranged in a respective recess provided for this purpose on the inlet element and / or on the outlet element.

[0017] According to the invention, the adjusting device comprises an actuator and a movable element for adjusting the flow cross-section in the channel. The movable element is preferably arranged to be axially displaceable within the channel. For example, the actuator can be designed as an electric machine. For example, the actuator can move the movable element within the channel by rotation or by linear movement to adjust the flow cross-section. In particular, the movable element is fixed circumferentially to the inlet element, i.e., rotationally fixed to the inlet element, and axially displaceable within the inlet element.

[0018] According to one embodiment, the movable element is designed as a circumferential stop for the forming element. In other words, the forming element, regardless of the position of the actuating device, is configured to come into contact with the movable element in a circumferential end position, thereby transmitting drive power from the input element to the output element essentially without the hydraulic fluid. When the direction of rotation changes after the forming element has reached a stop position on the movable element, the potential damping travel is maximized until the forming element reaches a second stop position on the movable element.

[0019] The invention also relates to a drive unit for a robot comprising a drive motor and a joint module according to the invention. For example, a gearbox can be arranged in the power flow between the drive motor and the joint module. The gearbox is preferably designed as a planetary gearbox, wave gearbox, or cycloidal gearbox. In particular, the joint module is integrated into an output shaft of the gearbox. Alternatively, the joint module, in particular the input element, can be rotationally fixed to an output shaft of the gearbox.

[0020] Furthermore, the invention also relates to a robot, in particular a cobot or a humanoid robot, with a joint module according to the invention, in particular with a drive unit according to the invention. For example, the joint module is provided for a robot arm and acts at least indirectly between two robot arm segments.

[0021] Further measures improving the invention are described in more detail below, together with a description of a preferred embodiment of the invention, with reference to the figures. Fig. 1 a simplified schematic representation of a robot, only partially shown, with a joint module according to the invention, Fig. 2 a simplified sectional view of the joint module and Fig. 3 another simplified sectional view of the joint module.

[0022] Fig. Figure 1 shows a section of a robot 12. A joint 13 is arranged between a first robot arm segment 12a and a second robot arm segment 12b, connecting the two robot arm segments 12a and 12b. To change the position of the two robot arm segments 12a and 12b relative to each other, the robot 12 has the drive unit 14 according to the invention, which includes a drive motor 15 designed as an electric motor, a gearbox 16, and the joint module 10. Thus, the drive motor 15, the gearbox 16, and the joint module 10 are integrated into one another. In particular, a rotor shaft of the drive motor 15 forms an input shaft of the gearbox 16, with the joint module 10 being arranged at least partially in the output shaft of the gearbox 16. Alternatively, the joint module 10 can be connected to the output shaft of the gearbox 16 via a flange connection.

[0023] Fig. 2 and Fig. Figure 3 shows the joint module 10 of the robot 12, where Fig. 3 a section view according to the section plane A in Fig. 2. The joint module 10 comprises an input element 1, which is indirectly connected to the drive motor 15 via the gearbox 16, an output element 2, which is arranged coaxially to the input element 1 and is connected to the input element 1 in a drive-enhancing manner, a fluid-tight channel 3 formed between the input element 1 and the output element 2 for receiving a hydraulic fluid, a forming element 4, which is designed to transmit drive power between the input element 1 and the output element 2 and to displace the hydraulic fluid in the channel 3, and an actuating device 5. The input element 1 and the output element 2 can rotate at least partially relative to each other about the axis of rotation D.

[0024] In this arrangement, the forming element 4 is rotationally fixed to the outlet element 2, and the channel 3 is designed as a recess in the inlet element 1. A first seal 8 and a second seal 9 are arranged between the inlet element 1 and the outlet element 2 and are configured to seal the channel 3 fluid-tight. The channel 3 has a variable flow cross-section. The adjusting device 5 comprises an actuator 6 and an axially displaceable element 7 for adjusting the flow cross-section in the channel 3. The displaceable element 7 is rotationally fixed to the inlet element 1, in particular arranged in a receiving bore provided for this purpose in the inlet element 1, and is designed as a stop element in the circumferential direction for the forming element 4.

[0025] The flow cross-section in channel 3 is currently at its maximum. When the movable element 7 is moved axially towards the outlet element 2, the flow cross-section in channel 3 decreases. Fig.Figure 2 shows a double arrow on the movable element 7, visualizing its range of motion within the channel 3. By changing the flow cross-section, damping of the movement of the shaped element 4 within the channel 3 is achieved. The actuating device 5 is used to position the movable element 7 and thus adjust the flow cross-section. In a fully open state of the actuating device 5, as shown, the flow cross-section is at its maximum, so that the flow cross-section essentially provides no damping of the movement of the shaped element 4 within the channel 3. Conversely, in a fully closed state of the actuating device 5, the flow cross-section is closed, so that the inlet element 1 and the outlet element 2 are rotationally fixed to each other via the hydraulic fluid in the channel 3.

[0026] Between the fully open and fully closed positions of the actuator 5, a multitude of positions are possible, thus enabling different flow cross-sections. Each of these positions of the actuator 5 results in a different flow cross-section and therefore a different damping of movement. The damping of movement can thus be variably adjusted via the actuator 5, depending on the situation. The damping of movement is always adjusted before the joint module 10 is moved. The joint module 10 is moved by supplying drive power from the drive motor 15 to the input element 1. Reference symbol list 1 Input element 2 Starting element 3-channel 4 Form element 5 Actuator 6 Actuator 7 movable element 8 first seal 9 second seal 10 Joint module 12 robots 12a first robot arm segment 12b second robot arm segment 13 joint 14 Drive unit 15 Drive motor 16 gearboxes A cutting plane D axis of rotation

Claims

[1] Joint module (10) for a robot (12) comprising an input element (1) which is configured to be connected, at least indirectly, to a drive motor (15), an output element (2) which is arranged coaxially to the input element (1) and is connected to the input element (1) in a drive-effective manner, a fluid-tight sealed channel (3) formed between the inlet element (1) and the outlet element (2) for receiving a hydraulic fluid, wherein the channel (3) has at least one variable flow cross-section, a shaped element (4) which is designed to transmit a drive power between the input element (1) and the output element (2) and to displace the hydraulic fluid in the channel (3), wherein a damping of the movement of the shaped element (4) in the channel (3) is adjustable by changing the flow cross-section, and an adjusting device (5) for adjusting the flow cross-section, characterized by , that the adjusting device (5) has an actuator (6) and a movable element (7) for adjusting the flow cross-section in the channel (3). [2] Joint module (10) according to claim 1, characterized by , that in a fully open state of the actuating device (5) the flow cross-section is at its maximum, so that the flow cross-section essentially does not cause any damping of the movement of the form element (4) in the channel (3). [3] Joint module (10) according to any of the preceding claims, characterized by , that in a fully closed state of the actuating device (5) the flow cross-section is closed, so that the inlet element (1) and the outlet element (2) are connected to each other in a rotationally fixed manner via the hydraulic fluid in the channel (3). [4] Joint module (10) according to any of the preceding claims, characterized by, that the form element (4) is connected to the output element (2) in a rotationally fixed manner and the channel (3) is formed as a recess in the input element (1). [5] Joint module (10) according to any of the preceding claims, characterized by , that the movable element (7) is designed as a stop element in the circumferential direction for the form element (4). [6] Joint module (10) according to any of the preceding claims, characterized by , that a first seal (8) and a second seal (9) between the inlet element (1) and the outlet element (2) are arranged to seal the channel (3) in a fluid-tight manner. [7] Drive unit (14) for a robot (12) comprising a drive motor (15) and a joint module (10) according to any one of claims 1 to 6. [8] Drive unit (14) according to claim 7, further comprising a transmission (16) arranged in the power flow between the drive motor (15) and the joint module (10). [9] Robot (12) comprising a joint module (10) according to any one of claims 1 to 6.

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