Rotary vane type gravity compensation device

Abstract

To provide a rotary vane type gravity compensation device.SOLUTION: A main body having a hollow cavity, a rotating shaft mechanism 2 pivotally mounted in the cavity through a shaft 21 and configured to drive at least two blades 22 to rotate in the cavity, at least two stoppers 3 mounted in the cavity and spaced apart from the blades to form a first pressure zone and a second pressure zone, and a pressure monitoring unit configured to communicate with the first pressure zone and the pressure accumulation container through an air inlet to form a communication loop, monitor a pressure change of the communication loop through a pressure detection device, and release an excessive pressure through a safety valve. In use, a high pressure gas is input to each of the first pressure zones by the air inlet and the pressure of the gas is higher than each of the second pressure zones to generate a torque at the axis of the shaft.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a robot arm gravity compensation device, and more particularly to a rotary vane type gravity compensation device. [Background technology]

[0002] Currently, most gravity compensation devices for industrial robot arms on the market are divided into three types: counterweights, coil springs, and pressure cylinders. Counterweights use their own weight to shift the center position of the robot, thereby reducing the burden on the torque generated by the actuator. This method increases the mass of the robot arm and the burden on the first axis actuator, resulting in low gravity compensation efficiency.

[0003] Coil spring cylinders are the primary gravity compensation devices for industrial robot arms, and provide gravity compensation through the reaction force generated by compressing or extending the spring. Most prior art focuses on optimizing the design of coil spring cylinders. Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional technologies, due to limitations on the spring material and external dimensions, such gravity compensation devices were often too large and heavy. The maximum elastic compression deformation that a spring can withstand is usually less than 50% of its free length, so the piston stroke of the spring cylinder is less than 50% of the total cylinder length, resulting in extremely low space utilization. Furthermore, before installing a coil spring gravity balance cylinder, the spring must be compressed to a specific length using a special jig before it can be safely installed on a robot arm, making the installation process complicated.

[0005] Some companies in the industry have focused on developing pneumatic or hydraulic gravity compensation mechanisms. Pressure cylinders generate auxiliary force by injecting high-pressure gas or liquid into the cylinder body to push a piston. However, this structure mainly uses a piston-type cylinder body, which requires a large space in the direction of piston movement. In addition, because the output shaft moves linearly and the stroke is fixed, the appropriate position of the connecting hinge between the robot and the piston must be carefully calculated according to the design of the cylinder body, resulting in a complicated design flow.

[0006] Therefore, the present inventors believed that the above drawbacks could be improved, and as a result of extensive research, they came up with the proposal of the present invention, which effectively improves the above problems through rational design.

[0007] The present invention has been made in view of the above circumstances, and aims to solve the above-mentioned problems. That is, the main object of the present invention is to provide a rotary vane-type gravity compensation device. Specifically, the vanes and stop blocks of the rotary shaft mechanism divide the chamber inside the main body into multiple pressure areas, and a pressure monitoring unit divides each pressure area into a high-pressure area and a low-pressure area. When the shaft rotates following the actuator of the robot arm, gas in the high-pressure area is pushed, generating auxiliary torque and reducing the load on the actuator. Furthermore, the auxiliary torque can be changed by adjusting the air pressure in the high-pressure area, making it convenient to use. The overall structure adopts a modular design, making it lightweight and easy to install and remove. [Means for solving the problem]

[0008] To achieve the above object, one embodiment of the rotary vane gravity compensator of the present invention includes a body having a hollow chamber, a rotary shaft mechanism pivotally mounted within the chamber by a shaft and driving at least two vanes to rotate within the chamber, at least two stop blocks mounted within the chamber and spaced apart from the vanes to define first and second pressure zones, and a pressure monitoring unit communicating with the first pressure zones and the pressure accumulator via an air inlet to form a communication loop, monitoring pressure changes in the communication loop with a pressure detector and releasing excess pressure with a safety valve. During use, high-pressure gas is introduced into each of the first pressure zones through the air inlet, making the gas pressure higher than that of each of the second pressure zones, and the high-pressure gas in each of the first pressure zones exerts a force on each of the vanes, generating a torque about the axis of the shaft. When the robot arm is operated, the output shaft of the actuator drives the shaft to rotate. When the shaft rotates in the same direction as the torque generated by the high-pressure gas, the torque generates a supplemental force, reducing the strain on the actuator.

[0009] At least the following points will become clear from the description and drawings to be described later. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing a rotary vane type gravity compensation device according to an embodiment of the present invention; [Figure 2] 1 is a schematic exploded view showing a rotary vane type gravity compensation device according to an embodiment of the present invention. [Figure 3] 1 is a schematic cross-sectional view showing a side of a rotary vane type gravity compensation device according to an embodiment of the present invention. [Figure 4] 1 is a schematic cross-sectional view showing a radial direction of a rotary vane type gravity compensation device according to an embodiment of the present invention. [Figure 5] 1 is a diagram illustrating a connection circuit configuration in which a rotary vane type gravity compensation device according to an embodiment of the present invention is installed on a robot arm. [Figure 6]1 is a schematic diagram showing a state in which a rotary vane type gravity compensation device according to an embodiment of the present invention is installed on a robot arm and in use; [Figure 7] 1 is a connection circuit diagram showing a state in which a rotary vane type gravity compensation device according to an embodiment of the present invention is installed on a robot arm; [Figure 8] 1 is a schematic diagram showing a series connection of rotary vane gravity compensation devices according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0012] Next, a rotary vane type gravity compensator 100 according to one embodiment of the present invention will be described with reference to FIGS.

[0013] A rotary vane type gravity compensator 100 according to one embodiment of the present invention comprises a main body 1, a rotary shaft mechanism 2, at least two stop blocks 3, and a pressure monitoring unit 4. The configuration of each component will be described below.

[0014] The main body 1 has a first housing 11 and a second housing 12, which are assembled facing each other to form a cylindrical hollow chamber 13. The first housing 11 has a first shaft hole 111 communicating with the chamber 13, and the second housing 12 has a second shaft hole 121 communicating with the chamber 13, with bearings 14 provided in both the first shaft hole 111 and the second shaft hole 121. The rotary shaft mechanism 2 has a shaft 21 and at least two blades 22, and both ends of the shaft 21 are pivotally mounted to two bearings 14, respectively, to reduce friction during rotation and are fixed by C-buckles 5. An attachment portion 211 is provided at one end of the shaft 21 pivoted into the second shaft hole 121. The attachment portion 211 is a plughole, keyhole, or other coupling mechanism that is connected to the output shaft of an actuator of a joint of a robot arm, and is preferably a keyhole in this embodiment.

[0015] 2 and 4, at least two vanes 22 are arranged at equal intervals on the outer periphery of the shaft 21, and at least two stop blocks 3 are respectively mounted in the chamber 13 and arranged at intervals from the vanes 22, thereby dividing the chamber 13 into a plurality of spaced-apart first pressure zones 131 and second pressure zones 132. In this embodiment, two vanes 22 are symmetrically mounted on the shaft 21, and the two vanes 22 rotate within the chamber 13 following the shaft. Two symmetrically mounted stop blocks 3 are also mounted within the chamber 13 and arranged at intervals from the two vanes 22, and the two vanes 22 are spaced apart from the two stop blocks 3, thereby forming two first pressure zones 131 and two second pressure zones 132, and the two first pressure zones 131 and the two second pressure zones 132 are arranged at intervals.

[0016] More specifically, each vane 22 has two blades 221 and a first seal member 222, and the two blades 221 sandwich the first seal member 222 between them and lock together, sealing the gap between the vane 22 and the chamber 13. Each stopper block 3 has two sector cylinders 31 and a second seal member 32, and the two sector cylinders 31 sandwich the second seal member 32 between them and lock together. The second housing 12 has two sets of mounting assemblies 122 symmetrically opened around the second shaft hole 121, which communicate with the chamber 13, and the sector cylinders 31 of each stopper block 3 are locked to the mounting assemblies 122, respectively. The second seal member 32 seals the gap between the stopper block 3 and the chamber 13 / shaft 21, and the pressure regions formed to be divided by combining with each vane 22 have good airtightness. To further ensure the airtightness of the entire structure, the gaps between the shaft 21 and the first housing 11 and the second housing 12, and the gaps between the first housing 11 and the second housing 12 are both sealed by seal rings 15, which are composed of a combination of an O-ring and a backup ring.

[0017] 3 and 4 , an input pipe 212 is axially installed at one end of the shaft 21 that is installed in the first axial bore 111, and a connecting pipe 213 that is connected to the input pipe 212 extends radially. The first housing 11 has an annular air guide groove 116 that wraps around its inner wall and is connected to the connecting pipe 213. Two branch pipes 112 are symmetrically installed within the first housing 11 and extend radially through the first housing 11. One end of each branch pipe 112 is formed with an inlet in the outer peripheral wall of the first housing 11, and the other end is connected to the annular air guide groove 116. Each branch pipe 112 is further connected to the chamber 13 by an output pipe 113, and an air guide hole 114 is formed in the inner wall of the first housing 11. The shaft 21 can be rotated to any angle, and the input pipes 212 are constantly connected to each of the first pressure zones 131, facilitating the introduction of high-pressure gas.

[0018] Incidentally, the air guide hole 114 is located in the first pressure region 131 and is adjacent to the stop block 3. During use, depending on the actual installation state, a coupling part 6 for connecting to the high-pressure source 7 is attached to the inlet of the input pipe 212 or any one of the branch pipes 112, and the remaining inlets are sealed by a first plug cover 115. When the shaft 21 is rotated to any angle, the input pipe 212 is constantly connected to each of the first pressure regions 131, thereby opening the high-pressure source 7 and introducing high-pressure gas into the two first pressure regions 131. The two first pressure regions 131 are connected to each other by the annular air guide groove 116, so that the gas pressures in the two first pressure regions 131 are consistent, preventing mismatches in assist torque caused by pressure deviations and preventing any impact on the assist effect of the actuator.

[0019] In the example shown in FIG. 4 , two exhaust pipes 123 extend radially through the peripheral wall of the second housing 12. Each exhaust pipe 123 is provided with a corresponding exhaust hole 124 in the inner peripheral wall of the second housing 12. Each exhaust hole 124 is located at a location where the sector cylinder 31 of the second pressure region 132 and the inner peripheral wall of the second housing 12 are joined together. The other sector cylinder 31 is further provided with an exhaust slot 311 that communicates with the exhaust hole 124 and the second pressure region 132. During use, a gas exhaust device exhausts gas from the second pressure region 132, and the second plug cover 125 seals the second pressure region 132 to prevent dust from entering, keeping the gas pressure in the second pressure region 132 lower than that in the first pressure region 131. The air pressures in the two second pressure regions 132 must be the same.

[0020] To further enhance the safety of the system, the present invention further includes a pressure monitoring unit 4 (see FIG. 5) having a pressure detection device 41, an air inlet 42, a safety valve 43, and a pressure accumulator 44. The air inlet 42 has a needle valve 421 and a protective cover 422 connected to the joint 6. The protective cover 422 is used to prevent dust from entering the needle valve, and the pressure detection device 41 is a pressure switch. The needle valve 421 is connected to the joint 6 and the pressure accumulator 44, respectively, to form a communication loop 45, and the pressure accumulator 44 increases the pressure change buffer volume. The pressure detection device 41 and the safety valve 43 are installed in the communication loop 45, and the pressure detection device 41 monitors pressure changes in the communication loop 45 by connecting a signal transmission cord to the control device 8 of the robot arm.

[0021] 4 and 5, in actual use, the rotary vane gravity compensation device of this embodiment is assembled to the output shaft of the actuator of the robot arm. Then, the protective cover 422 is opened, the needle valve 421 is connected to the adjustable high-pressure source 7, and the high-pressure source 7 is adjusted to the appropriate pressure. The needle valve 421 is opened to perform the air supply operation until the pressure detection device 41 indicates that the pressure is the same as that of the high-pressure source 7. At this time, the gas pressures in the pressure accumulator 44, the communication loop 45, and the first pressure region 131 are equalized. The air supply operation is completed by closing the needle valve 421, removing the high-pressure source 7, and replacing the protective cover 422. At the same time, the gas in each second pressure region 132 is exhausted to the outside through the exhaust pipe 123 by the gas exhaust device, so that the gas pressure in each second pressure region 132 is lower than that in each first pressure region 131 and equalized.

[0022] Based on the ideal gas equation pV = nRT, ignoring temperature changes, gas pressure increases as the volume of the gas decreases. Gas output is the product of pressure and the cross-sectional area subjected to the force, i.e., F = PA, where P is the pressure and A is the cross-sectional area subjected to the force. Therefore, when the joints of the robot arm rotate, the shaft is driven to rotate, causing each of the blades 22 to rotate toward each of the first pressure regions 131, continuously reducing the volume of the first pressure regions 131 and continuously increasing the pressure therein and increasing the auxiliary torque. The arrows in Figures 4 and 5 indicate the direction of the auxiliary torque, which coincides with the direction in which the actuator drives the shaft to rotate, thereby reducing the burden on the actuator. The present invention prevents a situation in which the pressure suddenly increases when the volume of each of the first pressure regions 131 decreases due to the increase in the volume of the pressure accumulator vessel 44, which could damage the device.

[0023] During robot arm operation, pressure detector 41 is connected to robot arm controller 8 to measure the real-time pressure in each of the first high-pressure areas 131. If the pressure exceeds the upper limit of a preset safety value, pressure detector 41 transmits a signal to controller 8 to stop the robot arm's operation and notify an operator of the occurrence of an abnormality. If the gas pressure in each of the first high-pressure areas 131 continues to rise due to external factors such as a sustained rise in environmental temperature, and the pressure reaches a pressure at which safety valve 43 operates, safety valve 43 automatically opens to release gas and prevent the pressure in communication loop 45 from rising again. Conversely, if pressure detector 41 detects that the gas pressure in each of the first high-pressure areas 131 is too low, it stops the robot arm's operation and notifies an operator to inspect the pipeline. After the abnormality is eliminated, the needle valve 421 of air inlet 42 is opened to replenish gas. When adjusting the auxiliary torque of the rotary vane gravity compensator, the gas pressure in the first pressure region 131, the communication loop 45, and the pressure accumulator vessel 44 can be changed simply by refilling or releasing gas using the needle valve 421. There is no need to change any of the components of the mechanism, and the operation is simple and fast.

[0024] 6 and 7, due to its geometric shape, when the industrial robot arm 9 moves, the gravity exerts torque on the lower arm pitch axis J2 and the upper arm pitch axis J3, increasing the load on the actuators. In contrast, a robot arm 9 used to transport heavy loads typically requires an additional gravity compensator to reduce the load on the actuators of the lower arm pitch axis J2 and the upper arm pitch axis J3, thereby reducing energy consumption. In practical application, the present invention provides two rotary vane gravity compensators 100 connected to the output shafts of the actuators of the lower arm pitch axis J2 and the upper arm pitch axis J3 of the robot arm 9, respectively. The first pressure regions 131 of the two rotary vane gravity compensators 100 are connected to the same pressure accumulator vessel 44, and the same pressure monitoring unit 4 forms the same communication loop 45, ensuring that the pressures of the two gravity compensators 100 are matched and interconnected. When the lower arm drives the upper arm to rotate and tilt forward, the gas in first pressure region 131a of gravity compensator 100a for the lower arm pitch axis J2 is compressed, increasing the pressure in the entire communication loop 45, increasing the assist torque of the gravity compensators for the lower arm pitch axis J2 and the upper arm pitch axis J3, and reducing the burden on their actuators.In contrast, when the upper arm rotates and tilts forward independently, the gas in first pressure region 131b of gravity compensator 100b for the upper arm pitch axis J3 is compressed, increasing the assist torque of the gravity compensators for the lower arm pitch axis J2 and the upper arm pitch axis J3, and reducing the burden on their actuators.

[0025] 8 shows another embodiment of the present invention, in which the main body 1 of rotary vane type gravity compensator 100a is fixedly coupled to one side of conversion adapter 101, and a coupling 6 is connected to the inlet of input pipe 212, with the remaining inlets communicating with first pressure region 131 all sealed by a first plug cover (not shown). The main body of another rotary vane type gravity compensator 100b is fixedly coupled to the other side of conversion adapter 101 and connected to a plug hole (not shown) of rotary vane type gravity compensator 100a installed opposite it by a shaft coupling mechanism (not shown). A coupling 6 is attached to the inlet of one of branch pipes 112, and the remaining inlets communicating with the first pressure region are all sealed by a first plug cover (not shown), thereby connecting the two rotary vane type gravity compensators. High-pressure gas is injected into the first pressure regions of the two rotary vane type gravity compensators, generating a greater auxiliary torque for the robot arm actuator than before they were connected.

[0026] As can be seen from the above embodiments, the rotary vane gravity compensation device of the present invention has the following technical advances and advantages: First, the auxiliary torque is easy to adjust. The present invention generates auxiliary torque using high-pressure gas instead of a coil spring, and during use, the auxiliary torque can be changed simply by adjusting the pressure in each of the air pressure areas within the chamber and the gas pressure in the communication loop and pressure accumulator. Since there is no need to replace components, convenience in use is improved. Second, it is easy to install and remove. When using the present invention, the rotary vane gravity compensator can be installed or removed directly by simply releasing the gas in the first pressure region in the chamber, and the operation can be completed without using any additional tools, which improves the speed and safety of installation and removal. Third, it saves mass and space. This invention uses high-pressure gas instead of a coil spring to generate auxiliary torque, further reducing the overall weight. Furthermore, by changing the gas compression method from vertical compression to rotary compression, the device's gravity is reduced and the axial volume is reduced, saving installation space. Fourth, the modular design allows for greater application flexibility. The present invention can output greater auxiliary torque by connecting a conversion adapter as needed, which increases application flexibility.

[0027] The above description is for the purpose of explaining the present invention, and should not be construed as limiting the invention described in the claims or narrowing its scope. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims. [Explanation of symbols]

[0028] 100 Rotary blade gravity compensator 100a Rotating blade gravity compensator 100b Rotary vane gravity compensator 101 Conversion Adapter 1 Main unit 11 First Housing 111 First shaft hole 112 Branch pipe 113 Output tube 114 Air guide hole 115 First plug cover 116 Annular air guide groove 12 Second Housing 121 Second shaft hole 122 Mounting assembly member 123 Exhaust pipe 124 Exhaust vent 125 Second plug cover 13 Chamber 131 First pressure region 131a First pressure region 131b First pressure region 132 Second Pressure Region 14 Bearings 15 Seal ring 2 Rotational axis mechanism 21 Shaft 211 Mounting part 212 Input tube 213 Communication pipe 22 Feather 221 Blade 222 first seal member 3 Stop block 31 Sector Cylinder 311 Exhaust slot 32 second seal member 4 Pressure Monitoring Unit 41 Pressure detection device 42 Air inlet 421 Needle Valve 422 Protective Cover 43 Safety valve 44 Pressure vessel 45 Connecting Loop 5 C-shaped buckle 6 Joint 7 High Pressure Source 8 Control Device 9. Robotic Arm J2 lower arm pitch axis J3 Upper arm pitch axis

Claims

1. a main body having a first housing and a second housing, the first housing and the second housing being assembled opposite to each other to form a cylindrical hollow chamber, the first housing having a first axial hole communicating with the chamber, the second housing having a second axial hole communicating with the chamber, the first axial hole and the second axial hole being positioned on the same axis and facing each other, the first housing having at least two air guide holes communicating with the chamber and used to supply air into the chamber, and the second housing having at least two exhaust holes communicating with the chamber and used to exhaust gas from the chamber; a rotary shaft mechanism having a shaft and at least two blades, wherein both ends of the shaft are pivotally mounted in the first shaft hole and the second shaft hole, respectively, the shaft is mounted in one end of the second shaft hole so as to be combined with an output shaft of an actuator of a robot arm, and the shaft is driven to rotate by the actuator, and the at least two blades are mounted on the circumferential side of the shaft and rotate within the chamber so as to follow the shaft; at least two stop blocks respectively installed in the chamber and spaced apart from the vanes, wherein a first pressure region and a second pressure region are formed at intervals between each of the vanes and two adjacent stop blocks, the air guide hole being located in the first pressure region and the exhaust hole being located in the second pressure region; a pressure monitoring unit having a pressure detection device, an air inlet, a safety valve, and a pressure accumulator container, wherein a communication loop is formed by the air inlet being communicated with the air guide hole and the pressure accumulator container, respectively, and a pressure change buffer volume is increased by the pressure accumulator container, and the pressure detection device and the safety valve are installed in the communication loop, and a signal transmission cord of the pressure detection device is connected to a control device of the robot arm, thereby monitoring pressure changes in the communication loop; First, the air inlet is opened and high-pressure gas is input from the air guide hole through the communication loop into each of the first pressure regions, making the gas pressure in each of the first pressure regions higher than that in each of the second pressure regions, and making the gas pressure in the pressure accumulator vessel and the communication loop equal to that in each of the first pressure regions. When air is continuously supplied to the pressure detection device and it is detected that the gas pressure in the communication loop has reached a set pressure value, the pressure detection device notifies the pressure detection device to close the air inlet to prevent the high-pressure gas from being input, the high-pressure gas in each of the first pressure regions exerts a force on each of the vanes and generates a torque about the axis of the shaft, and when the robot arm is actuated, the output shaft of the actuator drives the shaft to rotate, and when the direction of rotation of the shaft is the same as the torque generated by the high-pressure gas, the torque generates an auxiliary force to reduce the load on the actuator; the pressure detection device immediately monitors pressure changes in the communication loop when the robot arm is operated, and if it detects that the pressure value in the communication loop exceeds an upper limit value set by the pressure detection device, it transmits a signal to the control device to stop the operation of the robot arm; if the pressure continues to rise and reaches a rated value of the safety valve, the safety valve automatically opens to release excess pressure, thereby preventing the pressure in the communication loop from rising again; and if it detects that the pressure value in the communication loop is lower than a lower limit value set by the pressure detection device, it transmits a signal to the control device to stop the operation of the robot arm and replenish gas through the air inlet.

2. 2. The rotary vane gravity compensation device according to claim 1, wherein each of the vanes has two blades and a first seal member, the two blades sandwich the first seal member in between and lock with each other, the first seal member seals a gap between the vane and the chamber, and ensures airtightness of each of the pressure regions.

3. 2. The rotary vane gravity compensator according to claim 1, wherein each of the stop blocks has two sector cylinders and second seal members, the two sector cylinders sandwich the second seal member in between and are locked to each other, the second housing has two sets of mounting assembly members symmetrically opened around the periphery of the second shaft hole and communicating with the chamber, the sector cylinders of each of the stop blocks are locked to each other so as to correspond to each of the mounting assembly members, the second seal members seal gaps between the stop blocks and the chamber and the shaft, and the chamber is divided into a plurality of pressure zones by combining each of the vanes.

4. 2. The rotary vane gravity compensator according to claim 1, wherein an input pipe is installed axially at one end of the shaft installed in the first axial hole, and a communicating pipe is penetrated radially and communicated with the input pipe; the first housing is provided with an annular air guide groove wound around an inner wall thereof and communicated with the communicating pipe; two branch pipes are installed symmetrically within the first housing along the radial direction and penetrate the first housing, one end of each branch pipe forms an inlet in the outer peripheral wall of the first housing and the other end is communicated with the annular air guide groove, and each branch pipe is further communicated with the air guide hole by an output pipe; the shaft can be rotated to any angle to constantly communicate the input pipe with each of the first pressure zones, thereby introducing high-pressure gas.

5. 5. The rotary vane gravity compensator according to claim 4, wherein the inlet of the input pipe or any one of the branch pipes is fitted with a coupling for connection to a high-pressure gas source, and the remaining inlet is sealed by a first plug cover to prevent leakage of high-pressure gas.

6. 4. The rotary vane gravity compensator of claim 3, wherein two exhaust pipes extend radially through the peripheral wall of the second housing, each of the exhaust pipes has a corresponding exhaust hole formed in the inner peripheral wall of the second housing, each of the exhaust holes is located at a position where the sector cylinder of the second pressure region and the inner peripheral wall of the second housing are joined together, the sector cylinder is provided with an exhaust slot communicating with the exhaust hole and the second pressure region, and gas in the second pressure region is exhausted with the aid of a gas exhaust tool to make the gas pressure in the second pressure region lower than that in the first pressure region, and each of the exhaust pipes is sealed by a second plug cover to prevent dust from entering.

7. 2. The rotary vane gravity compensator according to claim 1, wherein the air guide hole is located in the first pressure region and adjacent to the stop block.

8. 2. The rotary vane type gravity compensation device according to claim 1, wherein an attachment portion is provided at one end of the shaft pivoted in the second shaft hole, the attachment portion being a plughole or a keyhole and used to connect the output shaft of the actuator of the robot arm, and bearings for supporting the shaft are provided in the first shaft hole and the second shaft hole, respectively, to reduce frictional force during rotation.

9. 2. The rotary vane type gravity compensation device according to claim 1, wherein the robot arm has a lower arm pitch shaft and an upper arm pitch shaft, and is connected to each of the rotary vane type gravity compensation devices via the output shaft of the actuator, the first pressure zones of each of the rotary vane type gravity compensation devices are connected to the same pressure accumulator vessel, and the same pressure monitoring unit forms the same communication loop, so that the pressures of each of the first pressure zones are matched and connected to each other.

10. 2. The rotary vane type gravity compensation device according to claim 1, wherein the main body has a conversion adapter attached to one side of the first housing, the other side of the conversion adapter is connected to the second housing of the other main body, and the two main bodies are connected by a shaft coupling to increase auxiliary torque.

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