Small electro-hydrostatic actuator

Abstract

The invention relates to a small electro-hydrostatic actuator, and belongs to the technical field of actuators, the small electro-hydrostatic actuator comprises a motor, a connecting pipe, a valve block, a plunger pump and a hydraulic oil cylinder, a first port of the connecting pipe sleeves the peripheral side of a motor output shaft and is fixed on a motor shell; one side of the valve block is fixed to the second port of the connecting pipe and is provided with a first groove, and a first liquid supply channel and a first liquid return channel are arranged in the valve block; the plunger pump is fixedly inserted into the first groove and is in transmission connection with the output shaft of the motor; the hydraulic oil cylinder is fixed to the bottom end of the valve block. According to the electro-hydrostatic actuator, the plunger pump is inserted and fixed in the first groove of the valve block, the size of the electro-hydrostatic actuator is reduced, and the weight of the electro-hydrostatic actuator is reduced; and then a first liquid supply channel and a second liquid supply channel are arranged in the valve block, and a liquid outlet hole of the plunger pump, the first liquid supply channel, the hydraulic oil cylinder, a first liquid return channel and a liquid inlet hole of the plunger pump are sequentially communicated to form a hydraulic driving loop, so that the sealing performance of the electro-hydrostatic actuator can be improved, and the purposes of miniaturization and light weight of the electro-hydrostatic actuator are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of actuators, and in particular to a small electrostatic hydraulic actuator. Background Art

[0002] Electrostatic hydraulic actuators are a new type of high-performance servo actuators that originated in the aerospace field and are gradually becoming a universal basic component for various large-scale equipment. Although electrohydraulic piston pumps usually dominate in many large applications, there is a lack of appropriate micro-electrostatic hydraulic actuators for use in hydraulic small applications such as prosthetics, exoskeleton designs, and robots.

[0003] The electro-hydrostatic actuator (EHA) is a high-power-to-weight ratio, high-efficiency, and highly integrated power-level digital hydraulic piston pump, which is mainly composed of a motor, a hydraulic pump, a hydraulic cylinder, a safety valve, a check valve, etc. As the existing electro-hydrostatic actuators are large in size and mostly use traditional electro-hydraulic servo valve-controlled piston pumps, they cannot adapt well to the use requirements of low-power application scenarios, and they must also ensure certain load requirements and safety. Therefore, tiny plug-in hydraulic components are integrated into the hydraulic valve block to form a direct-drive hydraulic pump-controlled piston pump, so that the EHA device has a smaller volume and weight, better response speed and displacement output control, and more convenient and quicker spatial transportability than traditional mechanisms.

[0004] Therefore, how to design a small electrostatic hydraulic actuator device that can be used for precise displacement and pressure control research and realize dynamic characteristic testing of plunger pumps under different loads is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The present invention provides a small electrostatic hydraulic actuator to solve the technical problem that the existing electrostatic hydraulic actuator is large in size and inconvenient for precise displacement and pressure control.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: a small electrostatic hydraulic actuator comprises: a motor, a connecting pipe, a valve block, a plunger pump and a hydraulic cylinder.

[0007] The connecting pipe is sleeved on the outer peripheral side of the motor output shaft from its first port gap, and the first port is fixed to the motor housing; one side of the valve block is fixed to the second port of the connecting pipe and is provided with a first groove opposite to the inner hole of the connecting pipe, and a first liquid supply channel and a first liquid return channel are provided inside the valve block, the liquid inlet of the first liquid supply channel and the liquid outlet of the first liquid return channel are both through the bottom of the first groove, and the liquid outlet of the first liquid supply channel and the liquid inlet of the first liquid return channel are both through the bottom end of the valve block; the plunger pump is inserted into the first groove and its input end is transmission-connected with the motor output shaft through a coupling to provide hydraulic power for the oil inside it as the motor output shaft rotates; the hydraulic cylinder is fixed to the bottom end of the valve block; the liquid outlet of the plunger pump, the first liquid supply channel, the hydraulic cylinder, the first liquid return channel and the liquid inlet of the plunger pump are sequentially connected to form a hydraulic drive circuit between the plunger pump and the hydraulic cylinder.

[0008] The beneficial effects of the present invention are: changing the structure of the traditional electrostatic hydraulic actuator, first inserting the plunger pump into the first groove of the valve block, reducing the overall volume of the electrostatic hydraulic actuator, and reducing the overall weight of the electrostatic hydraulic actuator; then using the interior of the valve block to set the first liquid supply channel and the second liquid supply channel. Since the liquid outlet of the plunger pump, the first liquid supply channel, the hydraulic cylinder, the first liquid return channel and the liquid inlet of the plunger pump are connected in sequence and a hydraulic drive circuit is formed between the plunger pump and the hydraulic cylinder, multiple hydraulic pipes can be omitted, and the sealing of the hydraulic drive circuit is improved, thereby achieving the miniaturization and lightweight goals of the electrostatic hydraulic actuator.

[0009] Based on the above technical solution, the present invention can also be improved as follows.

[0010] Furthermore, it also includes a unloading valve, the side of the valve block away from the motor is provided with a second groove and the interior of the valve block is provided with an unloading channel, the liquid inlet of the unloading channel passes through the first groove and the liquid outlet passes through the second groove; the unloading valve is inserted in the second groove; the liquid outlet hole of the plunger pump, the unloading channel and the liquid inlet hole of the unloading valve are connected in sequence.

[0011] A further beneficial effect of the above method is that by connecting the two ends of the unloading channel with the liquid outlet of the plunger pump and the liquid inlet of the unloading valve respectively, the unloading valve can be opened when the liquid pressure inside the plunger pump is too high to ensure the safe operation of the electrostatic hydraulic actuator.

[0012] Furthermore, it also includes a one-way valve, an accumulator, a three-way valve and a hydraulic elbow. The side of the valve block is provided with a third groove and the interior of the valve block is provided with a second liquid supply channel, the liquid inlet of the second liquid supply channel passes through the first groove and the liquid outlet thereof passes through the third groove; the one-way valve is inserted in the third groove; the accumulator is fixed on the valve block and its liquid inlet extends into the valve block; the three-way valve is fixed on the valve block and its liquid outlet extends into the valve block; the liquid outlet hole of the plunger pump, the second liquid supply channel, the one-way valve, the accumulator, the hydraulic elbow, the three-way valve and the liquid inlet hole of the plunger pump are connected in sequence to form a hydraulic energy storage circuit between the accumulator and the plunger pump.

[0013] The above-mentioned further beneficial effect is: by connecting the liquid outlet of the plunger pump, the second liquid supply channel, the one-way valve, the accumulator, the hydraulic elbow, the three-way valve and the liquid inlet of the plunger pump in sequence to form a hydraulic energy storage circuit, the hydraulic kinetic energy of the plunger pump can be converted into compression energy or potential energy and stored at an appropriate time. When the plunger pump needs it, the compression energy or potential energy is converted into hydraulic energy and released to replenish the plunger pump. When the instantaneous pressure of the plunger pump increases, it can absorb this part of the energy to ensure that the internal liquid pressure of the plunger pump is normal.

[0014] Further, the one-way valve, the third groove and the second liquid supply channel are two ones arranged opposite to each other and both of the two one-way valves are communicated with the accumulator.

[0015] Furthermore, another liquid inlet hole of the three-way valve is a liquid replenishing hole.

[0016] A further beneficial effect of the above method is that the convenience of replenishing oil by the plunger pump can be improved by using the other liquid inlet hole of the three-way valve as the liquid replenishment hole.

[0017] Furthermore, it also includes a safety valve, the top of the valve block is provided with a fourth groove and the inside of the valve block is provided with a third liquid supply channel and a second liquid return channel, the liquid inlet of the third liquid supply channel and the liquid outlet of the second liquid return channel both pass through the first groove, and the fourth groove passes through the third liquid supply channel; the safety valve is inserted in the fourth groove; the liquid outlet hole of the plunger pump, the third liquid supply channel, the safety valve, the second liquid return channel and the liquid inlet hole of the plunger pump are connected in sequence to form a hydraulic safety circuit between the safety valve and the plunger pump.

[0018] A further beneficial effect of the above-mentioned method is that the liquid outlet of the plunger pump, the third liquid supply channel, the safety valve, the second liquid return channel and the liquid inlet of the plunger pump are connected in sequence to form a hydraulic safety circuit. When the oil pressure inside the plunger pump is too high, the unloading valve can be opened to ensure the safe operation of the electrostatic hydraulic actuator.

[0019] Furthermore, the safety valve, the third liquid supply channel and the second liquid return channel are two channels arranged opposite to each other.

[0020] Furthermore, it also includes a plurality of sealing rings. The valve block is provided with sealing grooves at the bottom end corresponding to the liquid outlet of the first liquid supply channel and the liquid inlet of the first liquid return channel; and the plurality of sealing rings are respectively embedded in the plurality of sealing grooves.

[0021] Furthermore, the motor is a servo motor.

[0022] Furthermore, the plunger pump is a micro plunger pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a side view stereoscopic structural schematic diagram of a small electrostatic hydraulic actuator of the present invention;

[0024] Figure 2 It is a schematic diagram of a side-view stereoscopic structure of a small-sized electrostatic hydraulic actuator of the present invention after removing a connecting pipe;

[0025] Figure 3 It is a schematic diagram of a side view of the three-dimensional structure of a small electrostatic hydraulic actuator of the present invention after the connecting pipe and the valve block are removed;

[0026] Figure 4 It is a rear perspective structural schematic diagram of a valve block in a small electrostatic hydraulic actuator of the present invention;

[0027] Figure 5 It is a front perspective structural diagram of a valve block in a small electrostatic hydraulic actuator of the present invention;

[0028] Figure 6 It is a schematic diagram showing the structure of a hydraulic drive circuit, a load-unloading channel, a hydraulic energy storage circuit and a hydraulic safety circuit inside a valve block in a small-sized electrostatic hydraulic actuator of the present invention;

[0029] Figure 7 It is a schematic diagram showing the structure of a hydraulic drive circuit inside a valve block in a small electrostatic hydraulic actuator of the present invention;

[0030] Figure 8 It is a schematic diagram showing the structure of a discharge channel inside a valve block in a small electrostatic hydraulic actuator of the present invention;

[0031] Fig. 9 It is a schematic diagram showing the structure of a hydraulic energy storage circuit inside a valve block in a small electrostatic hydraulic actuator of the present invention;

[0032] Fig.10 The present invention is a schematic diagram showing the structure of a hydraulic safety circuit inside a valve block in a small electrostatic hydraulic actuator.

[0033] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0034] 1. Motor, 2. Connecting pipe, 3. Valve block, 31. First groove, 32. First liquid supply channel, 33. First liquid return channel, 34. Second groove, 35. Unloading channel, 36. Third groove, 37. Second liquid supply channel, 38. Fourth groove, 39. Third liquid supply channel, 310. Second liquid return channel, 4. Piston pump, 5. Hydraulic cylinder, 6. Coupling, 7. Unloading valve, 8. Check valve, 9. Accumulator, 10. Three-way valve, 11. Hydraulic elbow, 12. Safety valve. DETAILED DESCRIPTION

[0035] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0036] like Figure 1 and Figure 7 As shown, a small electrostatic hydraulic actuator includes: a motor 1, a connecting pipe 2, a valve block 3, a plunger pump 4 and a hydraulic cylinder 5.

[0037] The connecting pipe 2 is sleeved on the outer peripheral side of the output shaft of the motor 1 from its first port gap, and the first port is fixed to the housing of the motor 1; one side of the valve block 3 is fixed to the second port of the connecting pipe 2 and is provided with a first groove 31 opposite to the inner hole of the connecting pipe 2, and the interior of the valve block 3 is provided with a first liquid supply channel 32 and a first liquid return channel 33, the liquid inlet of the first liquid supply channel 32 and the liquid outlet of the first liquid return channel 33 are both through the bottom of the first groove 31, and the liquid outlet of the first liquid supply channel 32 and the first liquid return channel 33 are connected to the bottom of the first groove 31. The liquid inlets of the plunger pump 4 are all connected to the bottom end of the valve block 3; the plunger pump 4 is inserted into the first groove 31 and its input end is connected to the output shaft of the motor 1 through the coupling 6 to provide hydraulic power for the oil inside the motor 1 as the output shaft of the motor 1 rotates; the hydraulic cylinder 5 is fixed to the bottom end of the valve block 3; the liquid outlet of the plunger pump 4, the first liquid supply channel 32, the hydraulic cylinder 5, the first liquid return channel 33 and the liquid inlet of the plunger pump 4 are connected in sequence to form a hydraulic drive circuit between the plunger pump 4 and the hydraulic cylinder 5.

[0038] like Figure 8 As shown, in some specific embodiments, a unloading valve 7 may also be included, a second groove 34 is provided on the side of the valve block 3 away from the motor 1 and an unloading channel 35 is provided inside the valve block 3, a liquid inlet of the unloading channel 35 passes through the first groove 31 and a liquid outlet passes through the second groove 34; the unloading valve 7 is inserted in the second groove 34; the liquid outlet of the plunger pump 4, the unloading channel 35 and the liquid inlet of the unloading valve 7 are connected in sequence.

[0039] like Fig. 9As shown, in some specific embodiments, a one-way valve 8, an accumulator 9, a three-way valve 10 and a hydraulic elbow 11 may also be included. A third groove 36 is provided on the side of the valve block 3 and a second liquid supply channel 37 is provided inside the valve block 3. The liquid inlet of the second liquid supply channel 37 passes through the first groove 31 and the liquid outlet passes through the third groove 36; the one-way valve 8 is inserted into the third groove 36; the accumulator 9 is fixed on the valve block 3 and its liquid inlet extends into the valve block 3; the three-way valve 10 is fixed on the valve block 3 and its liquid outlet extends into the valve block 3; the liquid outlet hole of the plunger pump 4, the second liquid supply channel 37, the one-way valve 8, the accumulator 9, the hydraulic elbow 11, the three-way valve 10 and the liquid inlet hole of the plunger pump 4 are connected in sequence to form a hydraulic energy storage circuit between the accumulator 9 and the plunger pump 4.

[0040] Specifically, the one-way valve 8 , the third groove 36 and the second liquid supply channel 37 are two one-way valves 8 arranged opposite to each other, and both of the two one-way valves 8 are communicated with the accumulator 9 .

[0041] Specifically, the other liquid inlet hole of the three-way valve 10 is a liquid replenishing hole.

[0042] like Fig.10 As shown, in some specific embodiments, a safety valve 12 may also be included, a fourth groove 38 is provided at the top of the valve block 3 and a third liquid supply channel 39 and a second liquid return channel 310 are provided inside the valve block 3, the liquid inlet of the third liquid supply channel 39 and the liquid outlet of the second liquid return channel 310 both pass through the first groove 31, and the fourth groove 38 passes through the third liquid supply channel 39; the safety valve 12 is inserted into the fourth groove 38; the liquid outlet of the plunger pump 4, the third liquid supply channel 39, the safety valve 12, the second liquid return channel 310 and the liquid inlet of the plunger pump 4 are connected in sequence to form a hydraulic safety circuit between the safety valve 12 and the plunger pump 4.

[0043] Specifically, the safety valve 12 , the third liquid supply channel 39 and the second liquid return channel 310 may be two oppositely arranged ones.

[0044] In some specific embodiments, multiple sealing rings may be included. The valve block 3 is provided with sealing grooves at the bottom end corresponding to the liquid outlet of the first liquid supply channel 32 and the liquid inlet of the first liquid return channel 33; and the multiple sealing rings are respectively embedded in the multiple sealing grooves.

[0045] Specifically, the motor 1 may be a servo motor.

[0046] Specifically, the plunger pump 4 may be a micro plunger pump.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A small electrostatic hydraulic actuator, characterized in that: include: Motor (1), A connecting pipe (2), wherein the connecting pipe (2) is sleeved on the outer peripheral side of the output shaft of the motor (1) from a first port thereof and the first port is fixed to the housing of the motor (1); A valve block (3), one side of the valve block (3) is fixed to the second port of the connecting pipe (2) and is provided with a first groove (31) opposite to the inner hole of the connecting pipe (2); a first liquid supply channel (32) and a first liquid return channel (33) are provided inside the valve block (3); the liquid inlet of the first liquid supply channel (32) and the liquid outlet of the first liquid return channel (33) are both passed through the bottom of the first groove (31); the liquid outlet of the first liquid supply channel (32) and the liquid inlet of the first liquid return channel (33) are both passed through the bottom end of the valve block (3); A plunger pump (4), the plunger pump (4) being inserted and fixed in the first groove (31) and having an input end thereof being drivingly connected to the output shaft of the motor (1) via a coupling (6) so as to provide hydraulic power to the oil inside the plunger pump (4) as the output shaft of the motor (1) rotates; A hydraulic cylinder (5), wherein the hydraulic cylinder (5) is fixed at the bottom end of the valve block (3); the liquid outlet of the plunger pump (4), the first liquid supply channel (32), the hydraulic cylinder (5), the first liquid return channel (33) and the liquid inlet of the plunger pump (4) are connected in sequence to form a hydraulic drive circuit between the plunger pump (4) and the hydraulic cylinder (5).

2. A small electrostatic hydraulic actuator according to claim 1, characterized in that: The valve block (3) further comprises a relief valve (7); a second groove (34) is provided on the side of the valve block (3) away from the motor (1), and a relief channel (35) is provided inside the second groove; a liquid inlet of the relief channel (35) passes through the first groove (31) and a liquid outlet passes through the second groove (34); the relief valve (7) is inserted and fixed in the second groove (34); and a liquid outlet hole of the plunger pump (4), the relief channel (35) and a liquid inlet hole of the relief valve (7) are sequentially connected.

3. A small electrostatic hydraulic actuator according to claim 1, characterized in that: The invention also comprises a one-way valve (8), an accumulator (9), a three-way valve (10) and a hydraulic elbow (11); a third groove (36) is provided on the side of the valve block (3) and a second liquid supply channel (37) is provided inside the valve block; a liquid inlet of the second liquid supply channel (37) passes through the first groove (31) and a liquid outlet passes through the third groove (36); the one-way valve (8) is inserted and fixed in the third groove (36); the accumulator (9) is fixed on the valve block (3) and its The liquid inlet extends into the valve block (3); the three-way valve (10) is fixed on the valve block (3) and its liquid outlet extends into the valve block (3); the liquid outlet of the plunger pump (4), the second liquid supply channel (37), the one-way valve (8), the accumulator (9), the hydraulic elbow (11), the three-way valve (10) and the liquid inlet of the plunger pump (4) are connected in sequence to form a hydraulic energy storage circuit between the accumulator (9) and the plunger pump (4).

4. A small electrostatic hydraulic actuator according to claim 3, characterized in that: The one-way valve (8), the third groove (36) and the second liquid supply channel (37) are two mutually oppositely arranged one-way valves (8) and both of the two one-way valves (8) are in communication with the accumulator (9).

5. A small electrostatic hydraulic actuator according to claim 3, characterized in that: The other liquid inlet hole of the three-way valve (10) is a liquid replenishing hole.

6. A small electrostatic hydraulic actuator according to claim 1, characterized in that: The valve block (3) further comprises a safety valve (12); a fourth groove (38) is provided at the top of the valve block (3), and a third liquid supply channel (39) and a second liquid return channel (310) are provided inside the fourth groove; a liquid inlet of the third liquid supply channel (39) and a liquid outlet of the second liquid return channel (310) both pass through the first groove (31); the fourth groove (38) passes through the third liquid supply channel (39); the safety valve (12) is inserted and fixed in the fourth groove (38); the liquid outlet of the plunger pump (4), the third liquid supply channel (39), the safety valve (12), the second liquid return channel (310) and the liquid inlet of the plunger pump (4) are connected in sequence, so as to form a hydraulic safety circuit between the safety valve (12) and the plunger pump (4).

7. A small electrostatic hydraulic actuator according to claim 6, characterized in that: The safety valve (12), the third liquid supply channel (39) and the second liquid return channel (310) are two channels arranged opposite to each other.

8. A small electrostatic hydraulic actuator according to claim 1, characterized in that: It also comprises a plurality of sealing rings. The valve block (3) is provided with sealing grooves at the bottom end corresponding to the liquid outlet of the first liquid supply channel (32) and the liquid inlet of the first liquid return channel (33); and the plurality of sealing rings are respectively embedded in the plurality of sealing grooves.

9. A small electrostatic hydraulic actuator according to claim 1, characterized in that: The motor (1) is a servo motor.

10. A small electrostatic hydraulic actuator according to claim 1, characterized in that: The plunger pump (4) is a micro plunger pump.

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