Robot and load compensation device for robot

Abstract

The utility model relates to a robot and a load compensation device of the robot, the robot is provided with at least two connecting pieces (14, 16, 18) which are connected with each other in a hinged mode, the fluid type load compensation device comprises cylinders (62, 182), the cylinders are connected with the first connecting pieces (14, 16, 18) and the second connecting pieces (14, 16, 18) of the robot (10, 110) in a hinged mode, and the first connecting pieces (14, 16, 18) and the second connecting pieces (14, 16, 18) are connected with the cylinders (62, 182) in a hinged mode. The first coupling (14, 16, 18) and the second coupling (14, 16, 18) are coupled to each other in order to store energy and output the stored energy when a relative movement occurs between the first coupling (14, 16, 18) and the second coupling (14, 16, 18). The load compensation device has a first rotational joint, by means of which a first end of the cylinder is rotatably mounted on the first coupling part, and a second rotational joint, by means of which a second end of the cylinder is rotatably mounted on the second coupling part. At least the first rotational joint or the second rotational joint includes a spherical plain bearing.

Description

Technical Field

[0001] The utility model relates to a fluid load compensation device for a multi-axis robot. The multi-axis robot has at least two connecting pieces which are hingedly connected to each other. The connecting pieces can move relative to each other, in particular can pivot. Background Art

[0002] Multi-axis robots, in particular so-called industrial robots, are well known in the prior art. Typically, such robots include two, three or more interconnected and movable couplings. As examples, these couplings may be referred to as frames, swing arms, arms / cantilevers, hands, etc. Robots of the general type typically have a kinematic chain in series. Such robots are also referred to as articulated arm robots. Robots with two to seven or even more rotational axes or pivot axes are known. In serial motion, the couplings of the robot form a serial chain starting from the frame. That is, the drive on the frame or on the couplings arranged near the frame in the kinematic chain must not only hold and / or move the couplings that follow directly, but also, if necessary, hold and / or move other couplings in the kinematic chain in the direction of the end piece. This results in an increased holding torque or, in other words, generally results in an increase in load and inertia.

[0003] An industrial robot is generally understood to be a manipulator that is equipped with suitable tools for the automatic handling of objects and is programmable in multiple axes of motion, especially in terms of direction, position and workflow. An industrial robot essentially consists of a control device and a robot arm, which has multiple axes and, if necessary, multiple levers, which are moved by drives controlled by the control device. Industrial robots, especially industrial robots that carry relatively large loads, can have a weight or mass compensation system at least on their axes, especially on the second axis of the kinematic chain or a horizontally arranged axis, which includes, for example, a helical spring or other energy accumulator.

[0004] The load compensation device of the robot is usually arranged between two mutually adjacent coupling parts, which are movable relative to each other, in particular pivotable. Various types of load compensation devices are known, such as purely mechanical mass-based compensation devices, spring-based load compensation devices, fluid load compensation devices, etc. The goal of such load compensation devices is essentially to store static and / or kinetic energy when the coupling parts of the robot move relative to each other in order to provide this energy again in the event of a reverse movement. In this way, for example, unfavorable load situations or extreme positions of the coupling parts of the robot can be optimized, so that the holding torque or load torque to be applied by the drive is reduced.

[0005] WO96 / 31325A1 discloses a multi-axis industrial robot, which has a frame, a rocker arm, a cantilever and a manipulator, wherein these components are supported and driven in an articulated manner with each other, wherein the rocker arm is laterally arranged next to a system plane formed by the center of the frame axis and the hand flange, and the rocker arm and the cantilever each have a single-sided cantilever support device, wherein the rocker arm is connected to a static hydraulic counterweight, which is arranged on its side of the system plane, wherein the transmission device and bearing of the rocker arm are arranged on one side of the system plane, and the motor of the rocker arm is arranged on the other side of the system plane.

[0006] In addition, EP2301727A1 and DE102014104173A1 disclose load compensation devices for robots. Related load compensation devices can also be learned from EP3311961A1 and EP3311962A1.

[0007] It has been shown that when such load compensation devices are connected to the coupling of the robot, increased precision is required. Possible axial misalignments and / or tilting angles between the robot-side steering device and the load compensation device connected to its coupling can adversely affect the operating characteristics and service life of the load compensation device and of the entire robot. In the kinematic chain formed by the coupling of the robot and the load compensation device connected thereto, overlapping determinations may occur, which in turn leads to increased wear and increased force consumption.

[0008] Furthermore, deformations may occur at least temporarily under high loads, which also have a negative effect on the operating characteristics and service life. On the other hand, the robot including its load compensation should also be designed to be sufficiently compact and lightweight so that certain tolerance fluctuations and static / dynamic flexibility should be taken into account. Utility Model Content

[0009] Against this background, the object of the invention is to provide a fluid load compensation device for a multi-axis robot and a robot provided with such a load compensation device, which are designed to be sufficiently robust and insensitive. The load compensation device should be suitable for high loads and changing directions of movement. The load compensation device should be able to be integrated into the robot or connected to its connection parts with moderate effort.

[0010] According to a first aspect, the utility model relates to a fluid load compensation device for a multi-axis robot, the multi-axis robot having at least two connecting members articulated to each other, the load compensation device comprising:

[0011] a cylinder, the cylinder being articulatedly connected to the first link and the second link of the robot so as to store energy and output the stored energy when relative movement occurs between the first link and the second link,

[0012] a first rotary joint, through which the first end of the cylinder is rotatably supported on the first connecting member, and

[0013] a second swivel joint, by means of which the second end of the cylinder is rotatably supported on the second coupling element,

[0014] Wherein, at least the first rotation joint or the second rotation joint comprises a spherical sliding bearing.

[0015] The purpose of the utility model is achieved in this way.

[0016] Spherical plain bearings allow, on the one hand, a high load-bearing capacity and, on the other hand, good adaptability to changing directions of movement (oscillating movements), as often occur in robots. The spherical design of the plain bearing increases the ability to compensate for possible shape deviations and / or bearing deviations. In particular, spherical plain bearings can very well compensate for possible tilting positions of the cylinder or its revolving joints. In this way, for example, axial misalignments between a first revolving joint and a second revolving joint can be very well compensated. This allows a robot provided with a load compensation device to be operated safely, wherein a long service life is ensured.

[0017] Possible connection points for receiving the revolute joint between the coupling element of the robot and the cylinder of the load compensation device may have tolerances within a certain range. This relates, for example, to the axial orientation of two coupling elements of the robot that are pivotably connected to one another and are additionally functionally coupled to one another via the load compensation device.

[0018] Possible deformations and / or load peaks during operation of the robot have only a minor influence on the function and service life of the load compensation device due to the tolerance insensitivity. In addition, the bearing reactions of the robot in repetitive determinations can be minimized, thereby also reducing the risk of possible damage and / or excessive wear on the robot.

[0019] Spherical plain bearings are self-aligning plain bearings for high loads. Spherical plain bearings can withstand high impact loads and pressure loads, even in the case of non-constant oscillating movements. Spherical plain bearings have a favorable ratio between load-bearing capacity and required structural space, so that the load compensation device can be designed compactly overall. Possible connection points with the robot's coupling parts can be designed with appropriate structural space requirements. By being able to compensate for tolerances, the spherical plain bearing can be adapted to the current given operating state during the robot movement. In this way, for example, it is possible to react to tilting postures (for example angular offsets between the participating axes), which change depending on the relative position between the participating coupling parts.

[0020] In the context of the invention, the spherical plain bearing comprises, by way of example, a surrounding ring with a spherically (convexly) curved outer surface, which is adapted to a seat for the bearing. The seat has a spherical recess with a concave curvature. In other words, the spherical plain bearing can thus be pivoted during operation (at least within certain limits) along the spherical surface of the seat in order to compensate for tilting attitudes and / or other shape deviations and / or position deviations between the elements to be coupled to one another. Due to the planar contact along the spherical surface, a high load-bearing capacity is still obtained.

[0021] Sliding bearings can be made of metal, synthetic material and ceramic, for example. Sliding bearings are also known, which are designed as metal-polymer sliding bearings or fiber-reinforced composite bearings. Sliding bearings can be designed to be maintenance-free or low-maintenance. Preferably, the sliding bearing is designed in one piece and is formed, for example, by a (single) bearing ring.

[0022] According to an exemplary embodiment of the load compensation device, the first revolute joint and the second revolute joint comprise spherical sliding bearings. In this way, the tolerance compensation capability can be further improved. Since the distance between the first revolute joint and the second revolute joint changes when the mutually coupled coupling parts of the robot pivot relative to each other, an adaptation / orientation of at least one of the two sliding bearings can be performed during the movement.

[0023] According to another exemplary embodiment of the load compensation device, a first coupling part and a second coupling part of the robot are coupled adjacent to each other and are pivotably coupled to each other via an axis. In addition, the two coupling parts are connected to each other via the load compensation device, so that there is a certain risk for repeated determination of static state. Due to the coupling of the load compensation device to the tolerance-compensating spherical plain bearing, the precision requirements for the manufacture and assembly of the relevant components can be reduced without this having a negative impact on the operating performance and service life.

[0024] According to another exemplary design of the load compensation device, at least the first revolute joint or the second revolute joint is radially spaced from the shaft between the couplings. In this way, during relative rotation between the first coupling and the second coupling, the distance between the first revolute joint and the second revolute joint changes. If there is an inclination between the shafts of the first and second revolute joints, the inclination may change according to the corresponding pivot angle. Using at least one spherical plain bearing, possible fluctuations can be reacted to.

[0025] According to another exemplary embodiment of the load compensation device, at least the first revolute joint or the second revolute joint is spaced apart from an effective bearing plane of the shaft in the axial direction. Within the scope of the present invention, the effective bearing plane is oriented perpendicular to the shaft, wherein the effective bearing plane describes a contact surface in which the first coupling part and the second coupling part abut each other and can rotate relative to each other.

[0026] In robots, cantilever supports are often extended between two adjacent couplings. In this design, the effective bearing plane is the boundary surface between the two couplings. The associated revolute joint of the load compensation device cannot often be positioned precisely in this bearing plane. If there is an (axial) spacing from the bearing plane, when transmitting forces / torques via the robot's couplings and via the cylinders of the load compensation device, tilting moments must be taken into account. This can lead to deformations during operation due to corresponding relative pivoting and / or current loads. In this case, the spherical plain bearing can also perform corresponding compensating movements.

[0027] According to another exemplary design of the load compensation device, the first revolute joint and the second revolute joint each have a structural center, wherein the center of the first revolute joint and the center of the second revolute joint are axially offset from each other. For example, the axial offset is in the range from a few hundredths of a millimeter to a few tenths of a millimeter. This offset can cause a tilting posture, so that the involved couplings and the cylinders connecting the couplings are not oriented completely parallel to each other. However, if at least one of the two revolute joints is provided with a spherical sliding bearing, an adaptation to this position deviation can be achieved without adversely affecting the function.

[0028] According to another exemplary embodiment of the load compensation device, the first pivot joint and the second pivot joint each have an axis, wherein the axis of the first pivot joint and the axis of the second pivot joint are at least temporarily not aligned parallel to one another during a relative movement between the first coupling element and the second coupling element. This tilting can also be compensated by at least one spherical joint bearing.

[0029] A non-parallel orientation generally refers to a slight tilt / skew / tilt attitude between axes oriented parallel to each other. For example, a maximum tilt of 0.5° can be obtained during operation. For example, a maximum tilt of 2° can be obtained during operation. For example, a maximum tilt of 5.0° can be obtained during operation. Such tilt angles can be compensated. The precision requirements for the structural integration of the load compensation device can be reduced.

[0030] Usually, the goal is to connect the individual elements (connecting elements) of the robot's kinematic chain to one another with high rigidity, so that only low flexibility and, in particular, high repeatability occur during operation for positioning. In this case, it is advantageous if the load compensation device is able to compensate for possible tolerances at its revolute joints. This avoids adverse effects on the rigidity and accuracy of the robot's kinematic chain.

[0031] According to another exemplary embodiment of the load compensation device, at least the first or second pivot joint has a recess of at least segmented spherical design for accommodating a spherical plain bearing, which is formed in the cylinder. In other words, the cylinder has, for example, a bore for accommodating a bearing at at least one of its two ends facing away from each other. The bore comprises a spherical recess, which serves as a seat for the spherical plain bearing.

[0032] It goes without saying that neither the spherical recess nor the spherical plain bearing has a (complete) spherical shape. Instead, a spherical segment shape is usually given.

[0033] The connection to the coupling part of the robot can be realized, for example, by means of a pin (bearing pin) which is fastened to the coupling part of the robot and passes through a spherical plain bearing.

[0034] According to another exemplary embodiment of the load compensation device, at least the first or second revolute joint has a recess of at least segmented spherical design for accommodating a spherical plain bearing, which is formed in the coupling of the robot. In other words, according to this embodiment, the eye for accommodating the spherical plain bearing is not formed in the cylinder of the load compensation device, but in the coupling of the robot. Therefore, in this embodiment, the pin through which the spherical plain bearing passes is formed at the first end or the second end of the cylinder.

[0035] In an exemplary embodiment of the load compensation device, the cylinder is supported in a cantilever manner on a coupling element of the robot via a spherical plain bearing at least at its first or second end. In the case of a cantilevered support, increased bending moments and deformations must be taken into account. The spherical plain bearing can be adapted to the given load conditions.

[0036] According to a further exemplary embodiment of the load compensation device, the at least partially spherical recess has an introduction aid at least on one side on its circumference for mounting the spherical plain bearing in a mounting orientation inclined by at least 60° relative to the installation orientation.

[0037] In this way, the spherical plain bearing can be easily assembled even in the case of an integral design of the plain bearing and the recess for accommodating the plain bearing. The assembly orientation, in which the plain bearing is introduced into the support, is usually rotated by 90° relative to the installation orientation, when the plain bearing is installed. It goes without saying that, for example, installation is possible in an orientation that is at an angle of 80° to 100° (e.g. 85° to 95°) relative to the installation orientation. In other words, the plain bearing can thus be oriented transversely to its final installation position and introduced into the support. Here, contact can already be established between the spherical surface of the plain bearing and the recess, after which the plain bearing is rotated into its final installation orientation.

[0038] According to another exemplary embodiment of the load compensation device, the introduction aid has at least one flattened portion or two flattened portions offset by 180° on the circumference of the at least segmentally spherical recess. In the assembled state, the plain bearing is received in its seat in a form-fitting manner. However, the form-fitting contour is at least partially interrupted in order to form an introduction aid in which the plain bearing can be introduced into the seat transversely to its final installation orientation. Even if a certain pivoting movement is tolerated in the installation orientation, a secure fit is still ensured, since the usual compensating movement (in response to a given tilting angle) is significantly smaller than the pivoting angle between the installation orientation and the assembly orientation.

[0039] According to another aspect, the invention relates to a robot, in particular an industrial robot in the form of an articulated arm robot, which is provided with a load compensation device according to at least one of the embodiments described herein, which corresponds to two mutually articulated coupling parts of the robot.

[0040] According to an exemplary design of the robot, the load compensation device corresponds to a coupling part constructed as a turntable and a coupling part constructed as a rocker, wherein the cylinder is accommodated in an articulated manner on a revolute joint which is radially spaced apart from the rotation axis between the two coupling parts.

[0041] According to another embodiment of the robot, the cylinder is arranged in such a way that in the hydraulic cylinder, at the maximum relative movement between the turntable and the rocker arm, both an inward movement and an outward movement are generated. The maximum relative movement can, for example, include a pivoting movement between the two participating couplings, which includes the maximum possible pivoting angle. Thus, depending on which forces and moments are expected on the couplings (whether generated by the robot itself or by the loads to which they are subjected), a reduction of the applied moments can be achieved by the load compensation device in a number of operating states.

[0042] According to another exemplary embodiment of the robot, the load compensation device comprises two cylinders, which correspond to different degrees of freedom of movement of the robot, i.e. different pairings of coupling parts. In this case, it is also advantageous if the two cylinders are respectively supported on their revolving joints via at least one spherical plain bearing on the respectively assigned coupling part.

[0043] It goes without saying that the above-mentioned features of the present invention and the features to be explained below can be used not only in the respectively given combination but also in other combinations or alone without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Other advantages and features of the present invention are derived from the following description of a number of preferred embodiments with reference to the accompanying drawings.

[0045] Figure 1 A schematic side view showing a design of a robot provided with a load compensation device in a retracted state;

[0046] Figure 2 Show according to Figure 1 A side view of another embodiment of a robot provided with a load compensation device in a moved-in state;

[0047] Figure 3 Shown with respect to Figure 1 Another schematic diagram of a robot with a load compensation device that is oriented and rotated 90°;

[0048] Figure 4 shows a partial side view of a cylinder with an eyelet having a seat for receiving a spherical plain bearing;

[0049] Figure 5 Shown based on Figure 4 A partial side view of a spherical plain bearing for illustrating the compensating motion of the spherical plain bearing; and

[0050] Figure 6 A perspective view of a detail of a cylinder having a bore with a spherical recess and a spherical plain bearing is shown to illustrate the assembly process. DETAILED DESCRIPTION

[0051] Reference Figure 1 And additional references Figure 2 and Figure 3 , and the basic design scheme of the robot and the robot's load compensation device is explained.

[0052] Figure 1 The figure shows a side view of a robot 10 which is designed, for example, as an industrial robot. The robot 10 is designed as an articulated arm robot or a curved arm robot. The robot 10 has a serial kinematic chain.

[0053] For example, the robot 10 comprises couplings 12, 14, 16, 18, 20, 22 and 24 connected in series with each other. Each of the couplings 12, 14, 16, 18, 20, 22, 24 is movable relative to its adjacent coupling, in particular twistable or pivotable. The first coupling 12 can also be referred to as a base. An interface 26 is provided on the last coupling 24, for example for a so-called end effector. The kinematic chain can be supplemented with other couplings. A manipulator in the form of a clamp or the like can be accommodated on the interface 26, for example.

[0054] The robot 10 has various (movement) axes 30, 32, 34, 36, 38, 40, which are respectively configured between two couplings of the couplings 12, 14, 16, 18, 20, 22 and 24. The axes 30, 32, 34, 36, 38, 40 can also be referred to as drive axes and are provided with or connected to a drive / motor, such as an electric motor. A transmission device can be connected between the axes 30, 32, 34, 36, 38, 40 and the motors corresponding thereto. The axes 30, 32, 34, 36, 38, 40 generally allow a rotation / pivot movement between adjacent couplings 12, 14, 16, 18, 20, 22 and 24.

[0055] The shaft 30 is disposed between the couplings 12 and 14 and allows relative pivoting or relative torsion between the couplings 12 and 14. The shaft 32 is disposed between the couplings 14 and 16 and allows relative torsion or relative pivoting between the couplings 14 and 16. The shaft 34 corresponds to the couplings 16 and 18 and allows relative torsion and relative pivoting between the couplings 16 and 18. The shaft 36 is disposed between the couplings 18 and 20 and allows relative torsion or relative pivoting between the couplings 18 and 20. The shaft 38 is disposed between the couplings 20 and 22 and allows relative torsion or relative pivoting between the couplings 20 and 22. The shaft 40 is disposed between the couplings 22 and 24 and allows relative torsion or relative pivoting between the couplings 22 and 24.

[0056] With the help of Figure 1 In the robot 10 shown, the coupling 12 can also be referred to as a frame 42. The coupling 14 can also be referred to as a turntable 44. The coupling 16 can also be referred to as a rocker 46. The coupling 18 can also be referred to as an arm 48. The frame 42 is usually designed to fix the robot 12 on the bottom side. Likewise, depending on the application, designs of the robot 10 that are accommodated approximately on the ceiling side or on a (lateral) wall are also known.

[0057] The robot 10 is also provided with a load compensation device 60, according to Figure 1In the exemplary design shown, the load compensation device 60 includes a cylinder (e.g., a hydraulic cylinder) 62 having a cylinder housing 64 and a piston rod 66 inserted into the cylinder housing 64. The cylinder housing 64 and the piston rod 66 can be moved relative to each other in translation. At the cylinder housing 64, the cylinder 62 is pivotally connected to the coupling 14 at one end via a bearing or a revolute joint 68, that is, to the rotating disk 44. The hydraulic cylinder 62 is received on the coupling 16, i.e., the rocker 46, through the other end arranged in the piston rod 66, through a bearing or a revolute joint 70. The revolute joints 68, 70 are arranged eccentrically or radially offset from the shaft 32, respectively. When the couplings 14, 16 are pivoted relative to each other, a relative movement between the piston rod 66 and the cylinder housing 64 occurs. In this way, a fluid (e.g., hydraulic oil or gas) can flow into or be discharged from the cylinder housing 64.

[0058] The load compensation device 60 further includes a storage unit 74, which includes at least one accumulator 78. The storage unit 74 and the accumulator 78 are Figure 1 62 is shown schematically only. The accumulator is designed, for example, as a diaphragm accumulator, a bubble accumulator, a piston accumulator, a spring accumulator and / or according to other accumulator construction types. Exemplarily, a gaseous fluid (e.g., nitrogen or the like) is contained in the accumulator 78. Compared to hydraulic fluid, the gaseous fluid is highly compressible, so that the oil discharged during the movement of the cylinder 62 can pressurize the gaseous fluid in the accumulator 78. In this way, potential energy or kinetic energy can be stored as fluid energy.

[0059] In accordance with Figure 1 In the transition between the folded position and the unfolded position, the connecting piece 16 is pivoted relative to the connecting piece 14 in such a way that the piston rod 66 is first inserted deeper into the cylinder housing 64 and after overcoming the maximum insertion depth, the piston rod 66 is moved out of the cylinder housing 64 again when the connecting piece 16 continues to pivot.

[0060] refer to Figure 2 , another design of a robot, generally indicated at 110 , is shown. Figure 2 The robot 110 in Figure 1 The robot 10 of the embodiment of the present invention is designed in a similar manner. This applies in principle to the couplings 12, 14, 16, 18, 20, 22, 24 and the axes 30, 32, 34, 36, 38 and 40 assigned to these couplings. In the robot 110, the coupling 12 can also be referred to as a frame 42. Accordingly, the coupling 14 can be referred to as a turntable 44. The coupling 16 can be referred to as a rocker 46. The coupling 18 can be referred to as an arm 48.

[0061] The robot 110 is also equipped with a load compensation device, which Figure 2The load compensating device 160 is provided with a cylinder (e.g., a hydraulic cylinder) 62, which is designed according to Figure 1 The design of cylinder 62 is basically similar.

[0062] The cylinder 62 comprises a cylinder housing 64 and a piston rod 66 at its cylinder housing end, and is received on the coupling 14 via a bearing or a swivel joint 68. On the piston end, the cylinder 62 is received on the coupling 16 via a bearing or a swivel joint 70. Figure 1 The load compensation device 60 of FIG. 1 also has a storage unit 74 , which includes at least one pressure accumulator 78 . The storage unit 74 is associated with the cylinder 62 and is accommodated in particular on the cylinder housing 64 .

[0063] However, the load compensating device 160 further includes a second cylinder (eg, a hydraulic cylinder) 182. The cylinder 182 is Figure 2 and Figure 4 The cylinder 182 corresponds to the second connecting member 16 and the third connecting member 18. Figure 2 In the exemplary illustration of , the cylinder 182 is at least partially covered by the second coupling element 16 .

[0064] The cylinder 182 comprises a cylinder housing 184 and a piston rod 186, which can be inserted into and removed from the cylinder housing 184. The cylinder 182 is accommodated on the coupling 16 at its cylinder housing end via a bearing or a swivel joint 188. The cylinder 182 is accommodated on the coupling 18 at its piston end via a bearing or a swivel joint 190.

[0065] In principle, the pressure accumulator 78 or the second pressure accumulator can also be arranged at the second cylinder 182. However, it is conceivable Figure 2 , in which the second cylinder 182 is indirectly coupled to its pressure accumulator 78 via the first cylinder 62 .

[0066] The revolute joints 68, 70 of the cylinder 62 are respectively offset relative to the shaft 32 or spaced radially from the shaft 32. The revolute joints 188, 190 of the cylinder 182 are respectively offset relative to the shaft 34 or spaced radially from the shaft 34.

[0067] According to the exemplary terminology described above, the cylinder 182 is housed between the arm 48 and the swing arm 46 of the robot 110 .

[0068] Figure 2The exemplary configuration shown in also includes a connecting line 194, which extends between the cylinder 62 and the cylinder 182. The connecting line 194 creates a fluid connection between the cylinders 62, 182. The connecting line 194 extends, for example, from the cylinder housing 64 to the cylinder housing 184. In this way, the cylinders 62, 182 of the load compensating device 160 are functionally connected to one another.

[0069] according to Figure 2 Another feature of the exemplary design of the load compensation device 160 is that no storage unit with a pressure accumulator is provided in the cylinder 182 arranged between the coupling 16 and the coupling 18. Instead, the cylinder 182 also uses the storage unit 74 arranged in the cylinder 62. For this purpose, a connecting line 194 extends between the cylinder 182 and the cylinder 62, in particular between the cylinder housings 64, 184.

[0070] The load compensation device 160 is Figure 2 The advantage of the embodiment shown in FIG. 1 is that a separate storage unit 74 with at least one pressure accumulator 78 is also not provided in the second cylinder 182 itself. This avoids an increase in inertial masses, which must be overcome by the shaft 32 or the drive motor of the shaft 32 in order to pivot the coupling 16 and the subsequent couplings 18, 20, 22, 24 relative to the coupling 14. Furthermore, no additional effort is required for these components.

[0071] As a pair Figure 1 and Figure 2 In addition, Figure 3 Another view orientation of the robot indicated by 10 is shown. The robot 10 is relative to Figure 1 The view orientation shown is rotated approximately 90°. Figure 3 The robot 10 is shown in FIG. Figure 1 The side facing away from the connecting piece 24 or the interface 26 in the orientation.

[0072] The cylinder 62 of the load compensating device 60 is Figure 3 6 is only schematically shown. Cylinder 62 is connected to coupling 14 via a revolute joint 68 and to coupling 16 via a revolute joint 70. Axle 210 extends through revolute joint 68. Axle 212 extends through revolute joint 70. Axles 210, 212 should be structurally oriented as parallel to each other as possible. In addition, the axle should be oriented parallel to axis 32 so that couplings 14, 16 can pivot relative to each other about axis 32. Figure 3 , the structural center of the revolute joint 68 is denoted by 214. In addition, the structural center of the revolute joint 70 is denoted by 216.

[0073] Ideally, the structural centers 214, 216 are axially identically positioned, such as when the structural center 214 and the structural center 216 are positioned in a common plane oriented perpendicular to the axes 210, 212.

[0074] Figure 3 Further shown is a bearing plane designated 220, which designates the "interface" critical for the pivoting movement between the couplings 14, 16. There, a relative rotation takes place between the two couplings 14, 16. In other words, in accordance with Figures 1 to 3 In the embodiment of the present invention, the coupling part 16, which is called the rocker 46, is supported in a cantilever manner on the coupling part 14, which is called the rotating disk 44. In a cantilevered bearing, large forces and bending moments usually occur. If any forces are applied "outside" the bearing or laterally offset from the bearing, it can be said to be a cantilevered bearing.

[0075] exist Figure 3 It can also be seen in the design shown in that the first end of the cylinder 62 is also supported in a cantilever manner on the coupling 14 by means of a swivel joint 68, for example on a bearing dome 222. The structural center 214 of the swivel joint 68 is spaced apart from the bearing plane 220. The second end of the cylinder 62 with the swivel joint 70 is arranged between the two bearing edges 224 of the coupling 16 in this embodiment. There is no cantilever support for the swivel joint 70. Nevertheless, there is also an axial offset between the structural center 216 and the bearing plane 220.

[0076] Figure 3 It is shown that even with a structurally perfect orientation and alignment of the involved components, deformations may occur during operation of the robot 10 due to the acting forces and moments, which may lead to, for example, a tilted position between the axes 210, 212. In this case, the cylinder 62 may experience increased friction and increased wear. In principle, such unfavorable operating characteristics may also in turn affect the couplings 14, 16 and thus the operation of the robot 10.

[0077] Furthermore, account must be taken of the fact that, for example, the structural centers 214 , 216 are not perfectly aligned with one another (axially), ie there is an axial offset which leads to a tilting of the cylinder 62 and thus to an unfavorable alignment between the revolute joints 68 , 70 .

[0078] Therefore, a tilted position between the axes 210, 212 and / or an axial offset between the centers 214, 216 can adversely affect the operating characteristics of the load compensation device 60 and overall the operating characteristics of the robot 10. Nevertheless, the support of the cylinder 62 in the revolute joints 68, 70 must be subject to large forces and moments.

[0079] refer to Figures 4 to 6, shows a configuration in which a spherical plain bearing is used in at least one revolute joint 68 , 70 to compensate for position tolerances and / or shape tolerances.

[0080] Figure 4 A partial cross-sectional view of the cylinder 62 is shown in the case of one of the revolute joints 68, 70. In this embodiment, an eyelet 226 is formed at the end of the cylinder 62, in which a spherically designed recess 228 is formed. A spherical plain bearing 230 is located in the spherically designed recess 228. The spherical plain bearing has a spherical outer surface, which matches the spherical recess 228. In other words, both the spherical plain bearing 230 and the spherical recess 228 have spherical segments with the same diameter. The spherical plain bearing 230 is integrally constructed and is provided with an opening for a pin or the like, through which the shaft 210 extends. In this embodiment, the structural center 214 forms the midpoint of the spherical bearing 230 along the shaft 210.

[0081] The spherical recess 228 can also be referred to as a seat for a spherical plain bearing. Figure 4 The ideal orientation is shown, so that the shaft 210 is oriented concentrically with the configuration of the structural center 214 and the eyelet 226. The designation of the shaft 210 and the structural center 214 indicates that the eyelet 226 at the first end of the cylinder 62 is configured at the revolute joint 68. However, this should not be understood as limiting. The second end of the cylinder 62 having the revolute joint 70 can also have this configuration.

[0082] exist Figure 5 In the embodiment, the pin 240 is introduced into the spherical bearing 230. In this embodiment, the pin 240 is arranged on the connecting member 14 or the connecting member 16, for example, to provide a bearing position for the first rotating joint 68 or the second rotating joint 70. Figure 5 In the figure, the tilting position between the shaft 210 and the shaft 242 of the spherical bearing 230 is indicated by the eyelet 226. This tilting position (tilt between the shafts 210, 242) can be compensated both when it occurs statically and when it occurs dynamically by the compensating movement of the spherical plain bearing 230 in the spherically designed recess 228. Likewise, a high load-bearing capacity is still obtained by the mutually matching spherical surface (convex curvature, i.e., arched outward) and the spherical recess 228 (concave curvature, i.e., arched inward) of the spherical plain bearing 230. High loads and moments can be absorbed.

[0083] Figure 6 The assembly process for assembling the spherical plain bearing 230 into the seat formed by the spherical recess 228 in the eyelet 226 is shown. Figure 6On the end side shown, an introduction aid 250 is formed on the circumference 248 of the spherical recess 228. The introduction aid 250 comprises at least one flattened portion 252, which is formed as a depression on the edge of the spherical recess 228. Figure 6 In the embodiment of the present invention, two flattened portions 252, 254 are provided, which are offset 180° from each other with respect to the axis 242. The flattened portions 252, 254 allow the spherical sliding bearing 230 to be Figure 6 The sliding bearing 230 is introduced with its axis 210 in relation to the axis 242 by approximately 90° (at least 60°, for example 80° to 100°, for example 85° to 95°).

[0084] In other words, the plain bearing 230 can be introduced transversely, see arrow 260. In this way, taking into account the spherical shapes of the plain bearing 32 and the recess 228, the center of the spherical plain bearing 32 can be made to coincide or nearly coincide with the center 214 of the spherical recess 228. The spherical plain bearing 230 can then be pivoted about a rotation axis 264, which is perpendicular to the axis 210 of the spherical bearing 130 and perpendicular to the axis 242 of the spherical recess 228. Compare the curved arrows denoted by 262. In this way, the spherical plain bearing 230 can be pivoted from Figure 6 The loading orientation shown is adopted Figure 4 In the final installation orientation shown. In the installation orientation and at small pivot angles (see Figure 5 ), the spherical plain bearing 230 is fixed in a positively locking manner in the spherically designed recess 228, in particular when a pin 240 or the like extends through the spherical plain bearing 230. Nevertheless, tool-free assembly is achieved due to the introduction aid 250.

Claims

1. A fluid load compensation device (60, 160) for a multi-axis robot (10, 110), the multi-axis robot having at least two coupling parts (14, 16, 18) articulated to one another, in, The load compensation device (60, 160) comprises: A cylinder (62, 182) is hingedly connected to a first connecting member (14, 16, 18) and a second connecting member (14, 16, 18) of a robot (10, 110) so as to store energy and output the stored energy when relative movement occurs between the first connecting member (14, 16, 18) and the second connecting member (14, 16, 18), a first swivel joint (68, 188), through which the first end of the cylinder (62, 182) is rotatably supported on the first connecting member, and a second rotary joint (70, 190), wherein the second end of the cylinder (62, 182) is rotatably supported on the second connecting member via the second rotary joint, It is characterized in that At least the first revolute joint (68, 188) or the second revolute joint (70, 190) comprises a spherical sliding bearing (230).

2. The load compensation device (60, 160) according to claim 1, It is characterized in that The first revolute joint (68, 188) and the second revolute joint (70, 190) include a spherical sliding bearing (230).

3. The load compensation device (60, 160) according to claim 1 or 2, It is characterized in that A first link (14, 16, 18) and a second link (14, 16, 18) of a robot (10, 110) are adjacent to each other and are connected to each other in a pivotable manner via shafts (32, 34).

4. The load compensation device (60, 160) according to claim 3, It is characterized in that At least the first revolute joint (68, 188) or the second revolute joint (70, 190) is spaced apart from the shaft (32, 34) in the radial direction.

5. The load compensation device (60, 160) according to claim 3, It is characterized in that At least the first pivot joint (68, 188) or the second pivot joint (70, 190) is spaced apart axially from an effective bearing plane (220) of the shaft (32, 34).

6. The load compensation device (60, 160) according to claim 1 or 2, It is characterized in that The first rotating joint (68, 188) and the second rotating joint (70, 190) respectively have structural centers (214, 216), wherein the center (214) of the first rotating joint (68, 188) and the center (216) of the second rotating joint (70, 190) are offset from each other in the axial direction.

7. The load compensation device (60, 160) according to claim 1 or 2, It is characterized in that The first rotary joint (68, 188) and the second rotary joint (70, 190) respectively have axes (210, 212), wherein the axis (210) of the first rotary joint (68, 188) and the axis (212) of the second rotary joint (70, 190) are at least temporarily oriented non-parallel to each other when relative movement occurs between the first connecting member (14, 16, 18) and the second connecting member (14, 16, 18).

8. The load compensation device (60, 160) according to claim 1 or 2, It is characterized in that At least the first pivot joint (68, 188) or the second pivot joint (70, 190) has a recess (228) of at least segmented spherical design for accommodating the spherical plain bearing (230), which is formed in the cylinder (62, 182).

9. The load compensation device (60, 160) according to claim 1 or 2, It is characterized in that At least the first pivot joint (68, 188) or the second pivot joint (70, 190) has a recess (228) of at least segmented spherical design for accommodating the spherical plain bearing (230), which is formed in the coupling part (14, 16, 18) of the robot (10, 110).

10. The load compensation device (60, 160) according to claim 8, It is characterized in that The at least partially spherical recess (228) has an introduction aid (250) at least on one side on its circumference (248) for mounting the spherical plain bearing (230) in a mounting orientation inclined by at least 60° relative to the installation orientation.

11. The load compensation device (60, 160) according to claim 10, It is characterized in that The introduction aid (250) has at least one flattened portion (252, 254) or two flattened portions (252, 254) offset by 180° on the circumference (248) of the at least segmentally spherical recess (228).

12. A robot (10, 110), It is characterized in that The robot has a load compensation device (60, 160) according to any one of claims 1 to 11, which is assigned to two coupling parts (14, 16, 18) of the robot (10, 110) which are connected to each other in an articulated manner.

13. The robot (10, 110) according to claim 12, It is characterized in that The robot (10, 110) is designed as an industrial robot in the form of an articulated arm robot.

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