Outer rotor electro-hydraulic rotary actuator

Abstract

The present application relates to a kind of outer rotor electro-hydraulic rotary actuators, including swing hydraulic cylinder, motor, plunger pump and valve block, swing hydraulic cylinder includes front side end cover, rear side end cover, swing cylinder stator, swing cylinder rotor, front side end cover, rear side end cover are enclosed into the space between swing cylinder rotor and swing cylinder stator to become working chamber, moving blade and static blade are separated into independent working chamber I and working chamber II, valve block is fixedly installed in the inside of swing cylinder stator, motor includes motor stator and motor rotor, motor rotor is installed in the inside of motor stator and is connected with the cylinder body of plunger pump, valve block is provided with oil hole I being communicated with working chamber I and the working cavity of plunger pump one and oil hole II being communicated with working chamber II and the working cavity of plunger pump another.The present application has the beneficial effects of more compact structure, more accurate control of output torque and output position, with fully enclosed hydraulic circuit, more energy saving, safe and reliable.

Description

Technical Field

[0001] This invention relates to the field of hydraulic system equipment technology, and in particular to an external rotor electro-hydraulic rotary actuator. Background Technology

[0002] Electro-hydraulic actuators integrate an electric motor, hydraulic pump, and hydraulic cylinder into a volumetric regulating hydraulic circuit. The motor directly controls the output position and force of the hydraulic cylinder, leveraging the flexibility of electric drive and the high power and thrust of hydraulic drive while overcoming the drawbacks of traditional hydraulic systems, such as susceptibility to contamination, complex piping, and significant energy loss. Electro-hydraulic actuators are typical mechatronic integrated products with a high degree of integration and higher force and torque density compared to electromechanical drives. Oscillating hydraulic cylinders can reliably and stably output large torques at lower speeds, achieving a higher torque-to-weight ratio without requiring additional space, making them the most efficient and compact device for converting pressure into torque. Electro-hydraulic rotary actuators using oscillating hydraulic cylinders as actuators are ideal joint actuators for legged and humanoid robots, characterized by high power density and high control precision.

[0003] Chinese patent CN214424795U discloses an integrated electro-hydraulic servo rotary actuator, including a helical swing cylinder, an integrated motor pump, an integrated valve block, an accumulator, a controller, and an angle sensor. The helical swing cylinder includes a cylinder body, an output shaft, and a piston. The piston and the output shaft are arranged inside the inner cavity of the cylinder body. The piston is connected to the corresponding first meshing inner tooth of the inner cavity of the cylinder body through the outer helical right tooth. The outer cylindrical surface of the piston meshes with the inner helical left tooth of the inner cavity of the cylinder body.

[0004] The aforementioned prior art connects to the power supply via a power input line, receives control signals from the control room or sends feedback signals to the control room via a controller, and fixes the flange with screws, causing the piston to rotate together with the output shaft, output end cover, lock nut, and integrated valve block under the action of pressurized oil. The aforementioned prior art uses an internal rotor scheme, which generates additional axial dimensions when integrating the swing hydraulic cylinder, motor, hydraulic pump, and other components, thus limiting the axial usable space of the electro-hydraulic actuator. Summary of the Invention

[0005] The present invention aims to provide an external rotor electro-hydraulic rotary actuator to overcome the shortcomings of the prior art. The technical problem to be solved by the present invention is achieved through the following technical solution.

[0006] An external rotor electro-hydraulic rotary actuator includes a swing hydraulic cylinder, a motor, a plunger pump, and a valve block. The swing hydraulic cylinder includes a front end cover, a rear end cover, a swing cylinder stator, a swing cylinder rotor, moving blades, and stationary blades. The swing cylinder stator is installed inside the swing cylinder rotor. The lower end face of the stationary blade is fixedly connected to the swing cylinder stator, and its upper end face abuts against the inner surface of the swing cylinder rotor. The lower end face of the moving blade is fixedly connected to the inner surface of the swing cylinder rotor, and its upper end face abuts against the swing cylinder stator. The front end cover and the rear end cover are respectively fixedly connected to the front and rear sides of the swing cylinder stator. The end cover encloses the space between the oscillating cylinder rotor and the oscillating cylinder stator to form a working chamber. The moving blades and the stationary blades divide the working chamber into two independent working chambers, working chamber I and working chamber II. The valve block is fixedly installed inside the oscillating cylinder stator. The motor is installed inside the valve block. The motor includes a motor stator and a motor rotor. The motor rotor is installed inside the motor stator and connected to the cylinder body of the plunger pump. The valve block is provided with an oil hole I that communicates with working chamber I and one working chamber of the plunger pump, and an oil hole II that communicates with working chamber II and another working chamber of the plunger pump.

[0007] Preferably, the valve block is provided with an oil tank, the oil tank is provided with an elastic element, and the oil tank is connected to the plunger pump.

[0008] Preferably, an oil tank cover is installed at the rear opening of the oil tank, and the oil tank cover is fixedly installed on the valve block.

[0009] Preferably, a one-way valve is installed on the valve block, which allows the flow from the oil tank and the plunger pump to the working chamber of the swing hydraulic cylinder to be opened and closed in the reverse direction.

[0010] Preferably, the elastic element is an inflatable rubber ball.

[0011] Preferably, a pressure sensor is installed on the valve block, and the pressure sensor is used to detect the pressure in the working chamber I and the working chamber II respectively.

[0012] Preferably, an encoder is installed on the valve block, the encoder being used to detect the position of the plunger pump.

[0013] Preferably, an overflow valve is installed on the valve block, and the overflow valve is used to control the oil pressure in the working chamber I and the working chamber II to be below the rated working pressure.

[0014] Preferably, the valve block has an internal cavity, the plunger pump is installed inside the motor rotor and then installed together with the motor in the cavity, the front end of the plunger pump is sealed to the valve block, and the rear end of the cavity is sealed with a valve block cover.

[0015] The external rotor electro-hydraulic rotary actuator provided by the present invention has the following beneficial effects:

[0016] 1) The vane-type swing hydraulic cylinder is used as the actuator. The motor and piston pump are cleverly installed inside the swing cylinder stator of the swing hydraulic cylinder through the valve block, so as to realize the function of converting electrical energy into mechanical energy, then into hydraulic energy, and finally into torque for external output.

[0017] 2) The overall thickness is only the sum of the thicknesses of the swing cylinder rotor, the front end cover, and the rear end cover. Compared with existing technologies, the structure is more compact and saves more axial space.

[0018] 3) An oil tank is installed inside the valve block, so that the entire actuator forms a closed hydraulic circuit. There is no need to set up a centralized hydraulic pump station or connect to the outside hydraulic pipeline. It only needs to be powered to work normally. During the entire operation, it does not come into contact with the outside world and does not pass through easily worn components. Therefore, it is not easily contaminated and can be used for a long time without changing the hydraulic oil.

[0019] 4) The output torque and output position of the swing hydraulic cylinder are adjusted only by adjusting the speed of the motor. Compared with the traditional hydraulic system, there is no overflow loss and the working efficiency is higher.

[0020] 5) The oil tank is equipped with an elastic element, which allows the basic pressure of the hydraulic oil in the hydraulic circuit to fluctuate within a very small range under different working ambient temperatures, making the basic pressure in the entire hydraulic circuit more stable, thereby making the control of the actuator more precise.

[0021] 6) The setting of pressure sensors and encoders makes the control of the output torque and output position of the swing hydraulic cylinder more precise;

[0022] 7) The relief valve provides pressure protection for the hydraulic circuit within the actuator, enhancing safety and reliability. Attached Figure Description

[0023] Figure 1 This is a cross-sectional structural diagram of the present invention;

[0024] Figure 2 This is a three-dimensional structural diagram of the present invention;

[0025] Figure 3 This is a schematic diagram of the rear view structure of the present invention;

[0026] Figure 4 This is a schematic diagram of the exploded structure of the present invention;

[0027] Figure 5 This is a schematic diagram of the hydraulic circuit in an embodiment of the present invention;

[0028] The reference numerals in the attached figures are as follows: 1. Front end cover; 2. Valve block; 21. Oil hole I; 22. Oil hole II; 3. Piston pump; 4. Motor rotor; 5. Motor stator; 6. Rear end cover; 7. Valve block cover; 8. Encoder; 9. Oil tank cover; 10. Swing cylinder stator; 11. Swing cylinder rotor; 12. Moving vane; 13. Stationary vane; 14. Overflow valve; 15. Check valve; 16. Oil tank; 17. Pressure sensor; 181. Working chamber I; 182. Working chamber II. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] In this invention, the terms front, back, left, and right refer to... Figure 1 The figure shown is the baseline. Figure 1 In the diagram, the left side is front, the right side is back, the inward-facing side is left, and the outward-facing side is right.

[0031] Example 1:

[0032] An external rotor electro-hydraulic rotary actuator, improved in that it includes a swing hydraulic cylinder, a motor, a plunger pump 3, and a valve block 2. The swing hydraulic cylinder includes a front end cover 1, a rear end cover 6, a swing cylinder stator 10, a swing cylinder rotor 11, a moving blade 12, and a stationary blade 13. The swing cylinder stator 10 is installed inside the swing cylinder rotor 11. The lower end face of the stationary blade 13 is fixedly connected to the swing cylinder stator 10, and its upper end face abuts against the inner surface of the swing cylinder rotor 11. The lower end face of the moving blade 12 is fixedly connected to the inner surface of the swing cylinder rotor 11, and its upper end face abuts against the swing cylinder stator 10. The front end cover 1 and the rear end cover 6 are fixedly connected to the front and rear sides of the swing cylinder stator 10, respectively. The rear end cover 6 encloses the space between the swing cylinder rotor 11 and the swing cylinder stator 10 to form a working chamber. The moving blade 12 and the stationary blade 13 divide the working chamber into two independent working chambers, I181 and II182. The valve block 2 is fixedly installed inside the swing cylinder stator 10. The motor is installed inside the valve block 2. The motor includes a motor stator 5 and a motor rotor 4. The motor rotor 4 is installed inside the motor stator 5 and connected to the cylinder body of the plunger pump 3. The valve block 2 is provided with an oil hole I21 that communicates with the working chamber I181 and one working chamber of the plunger pump 3, and an oil hole II22 that communicates with the working chamber II182 and another working chamber of the plunger pump 3.

[0033] In this embodiment, refer to Figures 1 to 4 As shown, the swing cylinder rotor 11, as the actuator, is located outside the swing cylinder stator 10. The swing cylinder rotor 11 can rotate relative to the swing cylinder stator 10. The thickness of the stationary blade 13 and the moving blade 12 matches the thickness of the working chamber, dividing the working chamber into two independent working chambers, I181 and II182. The valve block 2 is fixedly connected to the swing cylinder stator 10. The plunger pump 3 and the motor are installed in the cavity inside the valve block 2. The motor stator 5 is fixedly connected to the valve block 2. The motor rotor 4 is located inside the motor stator 5 and is rotatably connected to the motor stator 5. The cylinder body of the plunger pump 3 is fixedly connected to the inside of the motor rotor 4. The swashplate, distribution plate, etc. of the plunger pump 3 are fixedly connected to the valve block 2. During operation, the rotation of the motor rotor 4 drives the cylinder of the plunger pump 3 to rotate, thereby causing the plunger pump 3 to generate hydraulic energy. This hydraulic energy then enters the working chamber of the swing hydraulic cylinder through the distribution mechanism of the plunger pump 3 and the oil hole on the valve block 2, thereby driving the moving blade 12 to rotate. The front end cover 1 and the rear end cover 6 are fixedly connected to the swing cylinder rotor 11, thereby driving the swing cylinder rotor 11, the front end cover 1 and the rear end cover 6 to rotate together, while the swing cylinder stator 10, the stationary blade 13 and the valve block 2 remain stationary.

[0034] Reference Figure 1 and Figure 3As shown, the working modes of the electro-hydraulic rotary actuator are divided into the following types:

[0035] Output positive torque: The forward rotation of the motor rotor 4 drives the cylinder of the plunger pump 3 to rotate in the forward direction, so that the high pressure oil generated by one working chamber of the plunger pump enters the working chamber II182 through the distribution mechanism of the plunger pump 3 and the oil hole II22 on the valve block 2. At this time, the pressure of the high pressure oil acts on the left side of the moving blade, so that the swing cylinder rotor 11 generates a counterclockwise output torque to overcome the load.

[0036] Output reverse torque: The motor rotor 4 rotates in the reverse direction, driving the cylinder of the plunger pump 3 to rotate in the reverse direction. This causes the high-pressure oil generated in the other working chamber of the plunger pump to enter the working chamber I181 through the distribution mechanism of the plunger pump 3 and the oil hole I21 on the valve block 2. At this time, the pressure of the high-pressure oil acts on the right side of the moving blade, causing the swing cylinder rotor 11 to generate a clockwise output torque to overcome the load.

[0037] Positive energy recovery: When the oscillating cylinder rotor 11 is subjected to a counterclockwise torque load, the working chamber I181 generates pressure, and the high-pressure oil acts on the plunger pump 3 through the oil hole I21, causing the plunger pump 3 to drive the motor rotor 4 to rotate in the forward direction, generating electrical energy.

[0038] Reverse energy recovery: When the oscillating cylinder rotor 11 receives a clockwise torque load, the working chamber II182 generates pressure, and the high-pressure oil acts on the plunger pump 3 through the oil hole II22, causing the plunger pump 3 to drive the motor rotor 4 to rotate in the opposite direction, generating electrical energy.

[0039] This embodiment provides an external rotor electro-hydraulic rotary actuator, which uses a vane-type oscillating hydraulic cylinder as the actuating unit. The oscillating cylinder rotor 11 of the oscillating hydraulic cylinder is located on the outermost side of the oscillating hydraulic cylinder as a torque output element. The motor and plunger pump 3 are cleverly installed inside the oscillating cylinder stator 10 of the oscillating hydraulic cylinder through the valve block 2, thereby realizing the function of converting electrical energy into mechanical energy, then into hydraulic energy, and finally into torque for external output. Moreover, the overall thickness is only the sum of the thicknesses of the oscillating cylinder rotor 11, the front end cover, and the rear end cover. Compared with the prior art, the structure is more compact and saves more axial space.

[0040] Furthermore, the valve block 2 has an internal cavity. The plunger pump 3 is installed inside the motor rotor 4 and is installed together with the motor in the cavity. The front end of the plunger pump 3 is sealed to the valve block 2, and the rear end of the cavity is sealed with a valve block cover 7.

[0041] Example 2:

[0042] Based on Example 1, referring to Figure 1 and Figure 5As shown, an oil tank 16 is provided inside the valve block 2, and an elastic element is provided inside the oil tank 16. The oil tank 16 is connected to the plunger pump 3.

[0043] Furthermore, an oil tank cover 9 is installed at the rear opening of the oil tank 16, and the oil tank cover 9 is fixedly installed on the valve block 2.

[0044] Furthermore, a one-way valve 15 is installed on the valve block 2. The one-way valve 15 allows the flow from the oil tank 16 and the plunger pump 3 to the working chamber of the swing hydraulic cylinder, and blocks it in the reverse direction. Even further, there are two one-way valves 15. One is located between one working chamber of the plunger pump 3 and the junction of the oil tank 16 and the working chamber I181 of the swing hydraulic cylinder. The other is located between the other working chamber of the plunger pump and the junction of the oil tank 16 and the working chamber II182 of the swing hydraulic cylinder.

[0045] In this embodiment, the oil tank 16 is the cavity formed by the empty groove inside the valve block 2 and the oil tank cover 9. The arrangement of the oil tank 16 makes the entire actuator form a closed hydraulic circuit. The working medium, i.e., hydraulic oil, does not require a centralized hydraulic pump station or external hydraulic pipeline connection during operation. It only needs power to work normally. It does not come into contact with the outside world during the entire working process and does not pass through easily worn components, so it is not easily contaminated and can be used for a long time without changing the hydraulic oil. The output torque and output position of the swing hydraulic cylinder are adjusted only by adjusting the speed of the motor. Compared with traditional hydraulic systems, there is no overflow loss, resulting in higher working efficiency.

[0046] In this embodiment, an elastic element is installed inside the oil tank 16. The oil pressure in the system's hydraulic circuit causes a certain compression of the elastic element inside the oil tank 16. When the operating environment temperature of the actuator changes, the density of the hydraulic oil in the system's hydraulic circuit changes. When the temperature rises, the density of the hydraulic oil decreases and its volume increases. The oil flows through the housing of the plunger pump 3 to the oil tank 16, and the elastic element is further compressed. When the temperature drops, the density of the hydraulic oil increases and its volume decreases. Part of the compression of the elastic element is released, thereby squeezing the oil to flow through the one-way valve 15 into the hydraulic circuit to compensate for the reduced volume of the hydraulic oil. By using this method, the base pressure of the hydraulic oil in the hydraulic circuit can only fluctuate within a very small range under different operating environment temperatures, making the base pressure in the entire hydraulic circuit more stable, thereby making the control of the actuator more precise.

[0047] Furthermore, the elastic element is an inflatable rubber ball.

[0048] Example 3:

[0049] Based on Example 1 or 2, refer to Figures 1 to 5As shown, a pressure sensor 17 is installed on the valve block 2. The pressure sensor 17 is used to detect the pressure in the working chamber I181 and the working chamber II182 respectively.

[0050] Furthermore, an encoder 8 is installed on the valve block 2, which is used to detect the position of the rear end cover 6.

[0051] In this embodiment, when controlling the output torque and output position of the actuator, the pressure values ​​of working chamber I181 and working chamber II182 detected by pressure sensor 17 are fed back to the controller. The controller controls the motor speed according to the feedback values, thereby precisely adjusting the pressure in working chamber I181 and working chamber II182, and thus indirectly controlling the output torque of the swing cylinder rotor 11. Furthermore, the position of the plunger pump 3 is detected by encoder 8 to obtain the rotational position of the motor rotor 4, which is fed back to the controller. The controller adjusts the motor speed according to the feedback values, thereby adjusting the output torque of the swing cylinder rotor 11, thus achieving more precise control of the position of the swing cylinder rotor 11.

[0052] Furthermore, the encoder 8 is a ring encoder 8.

[0053] Furthermore, an overflow valve 14 is installed on the valve block 2. The overflow valve 14 is used to control the oil pressure in the working chamber I181 and the working chamber II182 to be below the rated working pressure.

[0054] In this embodiment, refer to Figure 5 As shown, the relief valve 14 is configured such that when the working pressure of working chamber I181 or working chamber II182 exceeds the rated working pressure, the relief valve 14 connected to the chamber opens, allowing hydraulic oil to flow to another chamber through the relief valve 14 and the check valve 15, thereby playing a pressure protection role.

[0055] It should be noted that the above detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0056] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments described in this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0057] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0058] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0059] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatial relative descriptions used herein will be interpreted accordingly.

[0060] In the detailed description above, reference has been made to the accompanying drawings, which form part of this document. In the drawings, similar symbols typically identify similar parts unless the context otherwise indicates otherwise. The illustrated embodiments described in the detailed specification, drawings, and claims are not intended to be limiting. Other embodiments may be used and other changes may be made without departing from the spirit or scope of the subject matter presented herein.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An external rotor electro-hydraulic rotary actuator, characterized in that: The system includes a swing hydraulic cylinder, a motor, a piston pump (3), and a valve block (2). The swing hydraulic cylinder includes a front end cover (1), a rear end cover (6), a swing cylinder stator (10), a swing cylinder rotor (11), moving blades (12), and stationary blades (13). The swing cylinder stator (10) is installed inside the swing cylinder rotor (11). The lower end face of the stationary blade (13) is fixedly connected to the swing cylinder stator (10), and the upper end face abuts against the inner surface of the swing cylinder rotor (11). The lower end face of the moving blade (12) is fixedly connected to the inner side of the swing cylinder rotor (11), and the upper end face abuts against the swing cylinder stator (10). The front end cover (1) and the rear end cover (6) are fixedly connected to the front and rear sides of the swing cylinder stator (10), respectively. The front end cover (1) and the rear end cover (6) enclose the space between the swing cylinder rotor (11) and the swing cylinder stator (10) to form a working chamber. The moving blade (12) and the stationary blade (13) enclose the space between the swing cylinder rotor (11) and the swing cylinder stator (10). The working chamber is divided into two independent working chambers, I (181) and II (182). The valve block (2) is fixedly installed inside the stator (10) of the swing cylinder. The motor is installed inside the valve block (2). The motor includes a motor stator (5) and a motor rotor (4). The motor rotor (4) is installed inside the motor stator (5) and connected to the cylinder body of the plunger pump (3). The valve block (2) is provided with a connection between the working chamber I (181) and the cylinder body of the swing cylinder. The plunger pump (3) has an oil hole I (21) connected to one working chamber and an oil hole II (22) connected to the working chamber II (182) and the other working chamber of the plunger pump (3); the valve block (2) has a cavity inside, the plunger pump (3) is installed inside the motor rotor (4) and is installed together with the motor in the cavity, the front end of the plunger pump (3) is sealed to the valve block (2), and the rear end of the cavity is sealed with a valve block cover (7).

2. The external rotor electro-hydraulic rotary actuator according to claim 1, characterized in that: The valve block (2) is provided with an oil tank (16), and the oil tank (16) is provided with an elastic element. The oil tank (16) is connected to the plunger pump (3).

3. The external rotor electro-hydraulic rotary actuator according to claim 2, characterized in that: An oil tank cover (9) is installed at the rear opening of the oil tank (16), and the oil tank cover (9) is fixedly installed on the valve block (2).

4. The external rotor electro-hydraulic rotary actuator according to claim 1, characterized in that: A one-way valve (15) is installed on the valve block (2). The one-way valve (15) allows the oil tank (16), the plunger pump (3) to be connected to the working chamber of the swing hydraulic cylinder, and cuts off in the reverse direction.

5. An external rotor electro-hydraulic rotary actuator according to claim 2, characterized in that: The elastic element is an inflatable rubber ball.

6. The external rotor electro-hydraulic rotary actuator according to claim 1, characterized in that: A pressure sensor (17) is installed on the valve block (2), and the pressure sensor (17) is used to detect the pressure in the working chamber I (181) and the working chamber II (182) respectively.

7. The external rotor electro-hydraulic rotary actuator according to claim 1, characterized in that: An encoder (8) is installed on the valve block (2), which is used to detect the position of the plunger pump (3).

8. An external rotor electro-hydraulic rotary actuator according to claim 1, characterized in that: An overflow valve (14) is installed on the valve block (2). The overflow valve (14) is used to control the oil pressure in the working chamber I (181) and the working chamber II (182) to be below the rated working pressure.

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