Hydraulic power device

Abstract

The invention discloses a hydraulic power device which can be connected with a hydraulic execution device, is provided with a first cavity and a second cavity, and comprises a first driving device, a second driving device and a control device, the first pump body is driven by a first driving device; the output end of the first pump body is connected with the first cavity and the second cavity; the switch valve is connected between the first cavity and the first pump body; the input end of the hydraulic oil tank is connected with the second cavity; one end of the high-precision regulating valve is connected between the first cavity and the output end of the hydraulic oil tank, and the other end is connected with the second cavity, the input end of the hydraulic oil tank and the switching valve; the hydraulic oil cylinder is driven by controlling the first driving device and the switching valve, and the speed, pressure and / or telescopic displacement of the hydraulic oil cylinder during movement are / is adjusted by controlling the first driving device and the high-precision adjusting valve. The oil outlet amount of the first pump body is controlled by controlling the rotating speed of the first driving device, the high-precision adjusting valve is matched to adjust the oil way of the system, and the system can be applied to occasions meeting different application index requirements so as to achieve better comprehensive performance.

Description

Technical Field

[0001] This invention relates to the field of hydraulic transmission, and more specifically to a hydraulic power device. Background Technology

[0002] Numerical control and hydraulic technology are gradually emerging in the field of hydraulic control. In particular, the hydraulic control mode combining servo motors and fixed displacement gear pumps is favored by hydraulic professionals. It is commonly used in the control of hydraulic cylinders, especially in the control of the position, pressure and other actuators of the cylinder rod output. For example, high precision is required during the working stage of the rod to ensure that the rod can work properly. However, high precision is not required when the rod retracts. Therefore, existing hydraulic control systems can meet the requirements of high efficiency in one process but it is difficult to meet the requirements of high precision or low energy consumption. Even if the existing technology is upgraded to EHA (electro-hydraulic actuator), it still has the difficulties of low power-to-weight ratio and difficulty in meeting customers' requirements for ultimate integration and lightweighting. There is still room for improvement in improving the power-to-weight ratio, high efficiency and high precision control. Therefore, a hydraulic power device with better overall performance is needed. Summary of the Invention

[0003] The hydraulic power device of the present invention can effectively solve the problem that the overall performance of existing hydraulic drive equipment is difficult to improve.

[0004] According to one aspect of the present invention, a hydraulic power device is provided, which can be connected to a hydraulic actuator, the hydraulic actuator having a drive rod that causes the interior of the hydraulic actuator to form a first cavity and a second cavity, comprising:

[0005] First driving device;

[0006] A first pump body, which is driven by the first driving device; the output end of the first pump body is connected to the first cavity and the second cavity.

[0007] A switching valve is connected between the first chamber and the first pump body;

[0008] A hydraulic oil tank having a first end and a second end, the first end being connected to the first pump body;

[0009] A high-precision regulating valve, one end of which is connected to the first chamber, the second end of the hydraulic oil tank, and the switching valve, and the other end of which is connected between the second chamber and the first end of the hydraulic oil tank;

[0010] The hydraulic actuator is driven by controlling the first drive device and the switching valve, and the speed, pressure and / or telescopic displacement of the drive rod are adjusted by controlling the first drive device and the high-precision regulating valve.

[0011] In some embodiments, a second drive unit and a second pump body are also included. The second pump body is driven by the second drive unit, and the second end of the hydraulic oil tank is connected to the first chamber. The second pump body is used to drive the hydraulic oil tank, and a one-way valve is connected between the second pump body and the first chamber. Thus, the system is driven by two drive units, facilitating confluence to meet the need for higher efficiency.

[0012] In some embodiments, by controlling the opening of the switching valve, controlling the complete closure of the high-precision regulating valve, and controlling the first and second drive devices to drive the first and second pump bodies, the output ends of the first and second pump bodies merge and output to the first chamber, and the drive rod quickly retracts. This provides a high-efficiency, low-precision retraction condition, utilizing the merging of two gear pumps to meet the high-efficiency requirement.

[0013] In some embodiments, a first relief valve is connected between the first end of the hydraulic oil tank and the output end of the switching valve and the first pump body. Thus, the first relief valve is used to regulate the pressure of the system after the first and second pump bodies have combined.

[0014] In some embodiments, by controlling the switching valve to close, controlling the high-precision regulating valve to fully open, and controlling the first and second driving devices to drive the first and second pump bodies, the output end of the first pump body drives the second chamber. The output end of the first chamber and the output end of the second pump body merge and output to the high-precision regulating valve, forming a differential circuit between the high-precision regulating valve, the first chamber, and the second chamber. This provides a high-efficiency, low-precision extension condition, and the ability to form a differential circuit helps reduce energy consumption.

[0015] In some embodiments, a second relief valve is connected between the first end of the hydraulic oil tank and the rodless chamber and the high-precision regulating valve. Thus, the second relief valve is used to regulate the pressure of the system after the first and second pump bodies have combined.

[0016] In some embodiments, by controlling the switching valve to open and close the second pump body, and by controlling the first drive device to drive the first pump body, the first pump body, the second chamber, the first chamber, and the switching valve sequentially form a circuit. The oil quantity input to the second chamber is adjusted by controlling the high-precision regulating valve. This provides a high-precision, slow-extension operating condition, and the oil output in the system circuit can be adjusted via the high-precision regulating valve to provide high-precision output parameters.

[0017] In some embodiments, by controlling the high-precision regulating valve and the second pump body to close, and controlling the first drive device to drive the first pump body, the first pump body, the switching valve, the first chamber, and the second chamber sequentially form a circuit. The extension and retraction displacement of the drive rod during movement is adjusted by controlling the first drive device. This provides a medium-precision, slow-speed retraction condition. The oil output of the first pump body is controlled by controlling the rotational speed of the first drive device, thus providing medium-precision output parameters for the hydraulic cylinder.

[0018] In some embodiments, a shuttle valve is connected between the output end of the first pump body and the first end of the hydraulic oil tank.

[0019] In some embodiments, the hydraulic cylinder is connected to a displacement sensor, and a pressure sensor is connected between the rodless chamber and the high-precision regulating valve. The detection results of the displacement sensor and the pressure sensor are used to control the high-precision regulating valve. Thus, the displacement sensor and the pressure sensor are used to detect the extension and retraction displacement and pressure within the hydraulic cylinder, forming a closed-loop control with the high-precision regulating valve, facilitating the adjustment and display of various parameters.

[0020] The hydraulic power device of the present invention has the following advantages compared with the prior art:

[0021] This application controls a first drive device and a switching valve to drive a hydraulic cylinder, enabling the first pump body to operate in a hydraulic system. By controlling the rotational speed of the first drive device, the oil output of the first pump body is controlled, thereby controlling the output parameters of the hydraulic cylinder during movement. In conjunction with a high-precision regulating valve to regulate the oil circuit of the system, the oil output from the first pump body can be adjusted with high precision, thereby achieving the adjustment of the speed, pressure, and extension / retraction displacement of the hydraulic cylinder. It can be applied to occasions that meet different application requirements and can perform working conditions that conform to actual applications to achieve better overall performance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the hydraulic power device of the present invention;

[0023] Figure 2 This is a reference diagram for the rapid retraction of the cylinder rod in this invention;

[0024] Figure 3 This is a reference diagram showing the rapid extension of the cylinder rod in this invention;

[0025] Figure 4 This is a reference diagram for the slow extension of the cylinder rod in this invention;

[0026] Figure 5 This is a reference diagram for the slow retraction of the cylinder rod in this invention;

[0027] Figure 6 This is a reference diagram for the low-precision working condition of slow cylinder rod extension in this invention;

[0028] Figure 7 This is a partial cross-sectional schematic diagram of the hydraulic power device of the present invention.

[0029] In the diagram: 1-Hydraulic cylinder, 1a-Rodless chamber, 1b-Rod chamber, 1c-Cylinder rod, 2-High-precision regulating valve, 3-First drive device, 4-First pump body, 5-Switch valve, 6-First relief valve, 7-Hydraulic oil tank, 8-Check valve, 9-Second pump body, 10-Shuttle valve, 11-Second drive device, 12-Second relief valve, 13-Displacement sensor, 14-Pressure sensor. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] like Figure 1 As shown, this invention relates to a hydraulic power device, taking its ability to connect to and drive a hydraulic cylinder 1 as an example. This hydraulic power device can work with a controller or CNC system to control the components within the device. The hydraulic cylinder 1 has a drive rod (cylinder rod 1c), forming a first chamber and a second chamber inside the cylinder. The first chamber is a rod-type chamber 1b, and the second chamber is a rodless chamber 1a. Specifically, the hydraulic power device can drive the cylinder rod 1c to extend and retract via hydraulic oil. Of course, the hydraulic cylinder 1 is only one type of hydraulic device that works with this hydraulic power device; other hydraulic actuators that can be connected to this hydraulic power device are also applicable.

[0033] The present invention will now be described in further detail with reference to the accompanying drawings.

[0034] Figure 1 A hydraulic power unit according to one embodiment of the present invention is schematically shown. For example... Figure 1As shown, the dashed (outer) frame represents the hydraulic power unit, which includes a first drive unit 3, a first pump body 4, a second drive unit 11, a second pump body 9, a switching valve 5, a high-precision regulating valve 2, a shuttle valve 10, a first relief valve 6, a second relief valve 12, and a hydraulic oil tank 7.

[0035] like Figure 1 , Figure 7 As shown, both the first drive device 3 and the second drive device 11 are electric motors, such as servo motors or ordinary motors. In this embodiment, to improve the adjustment accuracy and facilitate control, the first drive device 3 uses a servo motor, and the second drive device 11 uses an ordinary motor. The first pump body 4 and the second pump body 9 are both used to accelerate the movement of hydraulic oil to drive the entire system. The first pump body 4 is a closed gear pump (bidirectional gear pump), or it can be a vane pump, with two output ports (end a and end b), which can accelerate the hydraulic oil at either port. The actuator 3 is connected to the first pump body 4 to drive the first pump body 4. The second pump body 9 is an open gear pump (one-way gear pump), or it can be a vane pump, with only one high-pressure oil port. The second drive device 11 is connected to the second pump body 9 to drive the second pump body 9 in one direction. The switching valve 5 is specifically a solenoid ball valve, which can open when energized and close when de-energized, and is used to control the opening and closing state of the oil circuit. The high-precision regulating valve 2 can be a high-frequency proportional valve or a servo valve. In this embodiment, the high-precision regulating valve 2 is a high-frequency proportional valve, which can regulate the oil circuit at a high frequency. It features multiple adjustment strokes, high response efficiency and adjustment precision, and high sensitivity. After triggering, it can act in a very short time, which helps improve the system's energy-saving and high-efficiency performance, making it particularly suitable for applications requiring high adjustment precision. The shuttle valve 10 is specifically a shuttle valve for closed gear pumps, adapted to the first pump body 4. It has a three-way port (ends C, D, and G), with ends C and D able to connect to end G. During operation, only one input end of the shuttle valve 10 can be connected to the output end for hydraulic oil output. For example, after hydraulic oil drive... When pressure is applied to the nearest port, the high-pressure end (e.g., port c), the valve closes, while the other port, the low-pressure end (port d), opens and connects to port g. Therefore, when the first pump body 4 is working, the shuttle valve 10 has a high-pressure end and a low-pressure end connected to the first pump body 4. The first relief valve 6 and the second relief valve 12 are both proportional relief valves, which can adjust the system pressure when the hydraulic power unit is working. The hydraulic oil tank 7 is used for oil return and replenishment, and has a first end and a second end (the first end and the second end are port e and port f, respectively), as well as a range gauge and a thermometer, etc.

[0036] In this embodiment, as Figure 1As shown, the second drive device 11 and the second pump body 9 are located inside the hydraulic oil tank 7. Alternatively, the second drive device 11 and the second pump body 9 can also be located outside the hydraulic oil tank 7, as long as they can drive the hydraulic oil tank 7 to output hydraulic oil. The f-end of the hydraulic oil tank 7 is connected to the rod chamber 1b. The output end of the second pump body 9 is used to drive the hydraulic oil tank 7 to output hydraulic oil. A one-way valve 8 is connected between the second pump body 9 and the rod chamber 1b, allowing the hydraulic oil tank 7 to output hydraulic oil via the second pump body 9. Hydraulic oil is unidirectionally output from end f of pump 7 to rod chamber 1b. End e of hydraulic oil tank 7 is connected to rodless chamber 1a via shuttle valve 10 (end g) or second relief valve 12. End a of the first pump body 4 is connected to rodless chamber 1a, and the other end is connected to rod chamber 1b via switching valve 5. That is, switching valve 5 is connected between rod chamber 1b and the first pump body 4. The two ports (end c and end d) of shuttle valve 10 are connected to end a and end b of the first pump body 4, respectively, and end g of shuttle valve 10 is connected to end e of hydraulic oil tank 7. The connection is as follows: the e-end of the hydraulic oil tank 7 is connected to the rodless chamber 1a via the g-end and c-end of the shuttle valve 10; one end of the first relief valve 6 is connected to the e-end of the hydraulic oil tank 7, and the other end is connected to the b-end of the first pump body 4 and the switching valve 5. In other words, the first relief valve 6 is connected between one end of the hydraulic oil tank 7 and the switching valve 5 and the b-end of the first pump body 4. In this embodiment, the c-end of the shuttle valve 10 is connected between the first relief valve 6 and the a-end of the first pump body 4; the second relief valve 12 is connected between the e-end of the hydraulic oil tank 7 and the rodless chamber 1a. Between chamber 1a and high-precision regulating valve 2, one end of the second relief valve 12 is connected to end e of hydraulic oil tank 7, and the other end is connected to end a of high-precision regulating valve 2 and first pump body 4. End e of hydraulic oil tank 7 is connected to first pump body 4 through shuttle valve 10. One end of high-precision regulating valve 2 is connected between rodless chamber 1a and end e of hydraulic oil tank 7. High-precision regulating valve 2 is connected to end e through second relief valve 12. The other end is connected to rod chamber 1b and switching valve 5 and communicates with end f of hydraulic oil tank 7.

[0037] In addition, the hydraulic power unit is used in conjunction with pressure sensor 14 and displacement sensor 13. Pressure sensor 14 is connected between rodless chamber 1a and high-precision regulating valve 2 to detect the pressure of hydraulic cylinder 1. Displacement sensor 13 is connected to hydraulic cylinder 1 to detect the extension and retraction displacement of cylinder rod 1c. In actual use, pressure sensor 14 and displacement sensor 13 are electrically connected to CNC system to transmit the detection results to CNC system, and then CNC system controls the actuators in hydraulic power unit, such as first drive device 3, second drive device 11, switching valve 5, and high-precision regulating valve 2.

[0038] The working principle of the hydraulic power device of the present invention mainly includes the following operating conditions:

[0039] ① Rapid retraction of the cylinder rod: such as Figure 2As shown, the arrows indicate the direction of hydraulic oil flow. By controlling the switch valve 5 to be energized (i.e., open) and the high-precision regulating valve 2 to be de-energized (i.e., fully closed), the first drive device 3 and the second drive device 11 are controlled to operate, causing the first pump body 4 and the second pump body 9 to operate. As a result, the hydraulic oil driven by the first pump body 4 (b-end oil port) and the second pump body 9 (f-end oil port) merges (upstream of the switch valve 5) and enters the rod chamber 1b to quickly retract the cylinder rod 1c. At the same time, the rodless chamber 1a is rapidly compressed, causing the hydraulic oil to flow quickly to the input end of the shuttle valve 10 (c-end is open). Since the volume of the rodless chamber 1a is larger than that of the rod chamber 1b, the excess hydraulic oil in the compressed rodless chamber 1a is returned to the hydraulic oil tank 7 through the shuttle valve 10. The first pump body 4, the switch valve 5, the rod chamber 1b, and the rodless chamber 1a form a circuit in sequence. In the above process, the first relief valve 6 can adjust the system pressure after the first pump body 4 and the second pump body 9 merge. For example, when the system pressure is too high, the first relief valve 6 (adjusting the hydraulic oil to return from top to bottom to the hydraulic oil tank 7) can reduce the pressure or the amount of hydraulic oil. The first drive device 3 and the second drive device 11 work simultaneously, and the system can form a merging flow, which makes the cylinder rod 1c retract quickly. This is suitable for the retraction of the cylinder rod 1c in non-precision working ranges. Of course, the first drive device 3 alone can also make the cylinder rod 1c retract quickly. Using the second drive device 11 can improve the efficiency of the hydraulic cylinder 1 on this basis.

[0040] In some embodiments, in the above-mentioned ① working condition, the high-precision regulating valve 2 can also be used as a bypass relief valve. That is, the high-precision regulating valve 2 acts as a diversion valve at the above-mentioned confluence point (diverting from top to bottom to end a of the shuttle valve 10) and diverting to the hydraulic oil tank 7. For example, when the pressure of the hydraulic cylinder 1 is too high, the high-precision regulating valve 2 diverts part of the oil to the output end of the rodless chamber 1a. It works in conjunction with the pressure sensor 14, the displacement sensor 13, and the second relief valve 12 to form a closed-loop control. It can accurately and stably regulate the pressure of the circuit formed by the first drive device 3 and the hydraulic cylinder 1, thereby achieving high-precision control of the force value output of the extension and retraction of the hydraulic cylinder 1. For example, if the pressure value detected by the pressure sensor 14 is not within the specified range, it is transmitted to the CNC system. The CNC system then controls the high-precision regulating valve 2 to adjust the pressure of the hydraulic cylinder 1 (the force area is a fixed value, and the flow rate and pressure are adjusted). The detection and adjustment of the displacement sensor 13 are similar. The flow rate and pressure of the hydraulic oil can be controlled by the high-precision regulating valve 2, thereby adjusting the extension and retraction displacement of the cylinder rod 1c.

[0041] ② The cylinder rod extends rapidly: such as Figure 3As shown, the arrows indicate the direction of hydraulic oil flow. By controlling the switch valve 5 to be in a de-energized state (i.e., the switch valve 5 is in a closed state), the high-precision regulating valve 2 is energized and fully opened, and the first drive device 3 and the second drive device 11 are controlled to work, causing the first pump body 4 and the second pump body 9 to operate. Thus, the first pump body 4 (driven by the oil port at end a) drives the hydraulic oil and quickly enters the rodless chamber 1a. The cylinder rod 1c extends quickly, and the hydraulic oil is driven from the rod chamber 1b. After the second pump body 9 is driven, the hydraulic oil in the hydraulic oil tank 7 is driven by the check valve 8 and merges with the hydraulic oil output from the rod chamber 1b (upstream of the switch valve 5), and then enters the high-precision regulating valve 2 to flow back to the rodless chamber 1a. Since the volume of the rodless chamber 1a is larger than that of the rod chamber 1b, the extension of the cylinder rod 1c causes the volume of the rodless chamber 1a to expand. The hydraulic oil tank 7 replenishes the hydraulic oil to the first pump body 4 through the shuttle valve 10 (output at end d). Therefore, in the above process, a differential speed circuit is formed between the high-precision regulating valve 2, the rod chamber 1b, and the rodless chamber 1a.

[0042] The above operating conditions apply to non-precision working ranges, representing a low-precision, high-efficiency condition for rapid cylinder extension. The first drive unit 3 and the second drive unit 11 operate simultaneously. The second relief valve 12 can regulate the system pressure after the first pump body 4 and the second pump body 9 merge. For example, if the system pressure is too high, the second relief valve 12 (which regulates the hydraulic oil flow from bottom to top) reduces the pressure or oil volume of the first pump body 4 and the second pump body 9. Since both operating conditions require merging, the only difference lies in the area of ​​the rod chamber 1b and the rodless chamber 1a. If the annular area of ​​the hydraulic cylinder 1 (the annular area of ​​the rod chamber 1b) is approximately equal to the area of ​​the cylinder rod 1c (the annular area of ​​the rodless chamber 1a), then the speeds of operating conditions ① and ② are approximately the same.

[0043] ③ The cylinder rod extends slowly: such as Figure 4 As shown, the arrows indicate the direction of hydraulic oil flow. By controlling the second drive device 11 to close, the second pump body 9 is in a non-operating state. The control switch valve 5 is energized, making it open. At this time, the control first drive device 3 is opened, making the first pump body 4 in an operating state. The first pump body 4 (driven by the oil port at end a) drives the hydraulic oil into the rodless chamber 1a. The hydraulic oil is output from the rod chamber 1b and enters the switch valve 5, then circulates back to end b of the first pump body 4. Since the volume of the rodless chamber 1a is larger than that of the rod chamber 1b, the extension of the cylinder rod 1c causes the volume of the rodless chamber 1a to expand. The hydraulic oil tank 7 replenishes the hydraulic oil to end b of the first pump body 4 through the shuttle valve 10 (output at end d). Therefore, the first pump body 4, the rodless chamber 1a, the rod chamber 1b, and the switch valve 5 form a circuit in sequence. In addition, the high-precision regulating valve 2 is controlled to be in a high-frequency regulating state, that is, the flow rate is regulated by the high-precision regulating valve 2, so that the hydraulic oil driven by the first pump body 4 can be partially output to the switch valve 5 through the high-precision regulating valve 2, thereby achieving high-precision regulation.

[0044] The above-mentioned working conditions are applicable to high-precision working conditions with slow extension within the precision working range. This working condition is a power-consuming working condition. Under the premise of meeting the precision requirements, it can meet the energy-saving requirements. The second relief valve 12 can adjust the pressure of the hydraulic oil output by the first pump body 4. For example, if the pressure in the circuit is too high, the hydraulic oil can be output to the hydraulic oil tank 7 through the second relief valve 12. The high-precision regulating valve 2 can adjust the amount of oil entering the rodless chamber 1a. The displacement sensor 13 can detect the displacement of the cylinder rod 1c in the hydraulic cylinder 1, and the rotation speed of the first drive device 3 can also adjust the total amount of hydraulic oil output by the first pump body 4. The amount of oil entering the rodless chamber 1a, the stroke detected by the displacement sensor 13, and the high-precision regulating valve 2 form a closed loop of control. The extension displacement of the cylinder rod 1c and the output pressure and speed are detected in real time, and adjusted by the high-precision regulating valve 2 and the first drive device 3 to achieve the precision requirements.

[0045] In some embodiments, such as Figure 6 As shown, a working condition with slow rod extension and no high-precision adjustment is provided. This working condition is largely the same as the operating mode in condition ③, except that the high-precision regulating valve 2 is completely closed in this embodiment, eliminating the high-precision adjustment method in the circuit. This is suitable for situations where the rod 1c extends slowly and the precision requirement is low. Specifically, the first pump body 4 (driven by the oil port at end a) drives hydraulic oil into the rodless chamber 1a, and the hydraulic oil is output from the rod chamber 1b and enters the switching valve 5, then circulates back to end b of the first pump body 4. The first pump body 4, rodless chamber 1a, rod chamber 1b, and switching valve 5 form a circuit in sequence. Since the volume of the rodless chamber 1a is larger than that of the rod chamber 1b, the extension of the rod 1c causes the volume of the rodless chamber 1a to expand. The hydraulic oil tank 7 replenishes hydraulic oil to end b of the first pump body 4 through the shuttle valve 10 (output at end d). It can be seen that by controlling the rotational speed of the first pump body 4 to control the flow rate of the hydraulic oil in the circuit, the working condition of slow extension with low precision can be achieved.

[0046] ④ Slow retraction of the cylinder rod: such as Figure 5As shown, the arrows indicate the direction of hydraulic oil flow. By controlling the second drive device 11 to close, the second pump body 9 is in a non-operating state. The high-precision regulating valve 2 is de-energized and in a fully closed state. The first drive device 3 is controlled to operate, causing the first pump body 4 (driven by the oil port at end b) to drive the hydraulic oil through the switching valve 5 into the rod chamber 1b. The hydraulic oil is output from the rodless chamber 1a and enters end a. At the same time, it passes through the input end of the shuttle valve 10 (end c is open). Since the volume of the rodless chamber 1a is larger than that of the rod chamber 1b, the cylinder rod 1c contracts, causing the volume of the rodless chamber 1a to decrease. The excess hydraulic oil is finally returned to the hydraulic oil tank 7 through the shuttle valve 10. Therefore, the first pump body 4, the switching valve 5, the rod chamber 1b, and the rodless chamber 1a form a circuit in sequence. It should be noted that the switching valve 5 is an electromagnetic ball valve, which has a unidirectional output effect. In actual use, the electromagnetic ball valve can be closed mainly to avoid the hydraulic oil backflow when the cylinder rod 1c is subjected to external force, which would affect the operation of the hydraulic system. Closing the electromagnetic ball valve can further ensure the effective operation of the hydraulic system.

[0047] The above working conditions are applicable to the medium-precision retraction of cylinder rod 1c. After the high-pressure oil is output from the first pump body 4, the speed regulation of the first pump body 4 and the displacement sensor 13 form a closed loop of control, which can accurately control the slow and medium-precision retraction of cylinder rod 1c in the oil cylinder.

[0048] In summary, this application controls the first drive device 3 and the high-precision regulating valve 2 to adjust the extension of the cylinder rod 1c during the movement of the hydraulic cylinder 1, providing customers with the required pressure, speed, and / or telescopic displacement. Combined with the closed-loop control of the high-precision regulating valve 2, pressure sensor 14, and first relief valve 6, high-precision control of the output pressure and displacement can be achieved. It boasts high efficiency; the rapid retraction and extension of the cylinder rod 1c (in its non-precision working range) can be further improved through confluence. The cylinder rod 1c can be adjusted to ensure sufficient energy saving during high-precision or high-efficiency movements. The actuators are lightweight and can be integrated into a more compact power unit. Furthermore, the power unit's weight is minimized to meet the high-force output of the cylinder rod 1c, achieving a high power-to-weight ratio. By utilizing existing actuators to improve the hydraulic system, better performance and higher cost-effectiveness are achieved. Therefore, the hydraulic power unit of this application can meet the requirements of efficient retraction at low precision and slow extension at high precision. By optimizing the hydraulic system, a balanced match of various performance characteristics is achieved, resulting in better overall performance.

[0049] The above description is merely a preferred embodiment of the present invention. To simplify the description, not all possible combinations of the various technical features in the above embodiments have been described, and this is not intended to limit the present invention in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A hydraulic power unit capable of being connected to a hydraulic actuator, the hydraulic actuator having a drive rod that forms a first cavity and a second cavity inside the hydraulic actuator, characterized in that, include: First driving device; A first pump body, the first pump body being driven by the first driving device; The output end of the first pump body is connected to the first chamber and the second chamber; A switching valve is connected between the first chamber and the first pump body; A hydraulic oil tank having a first end and a second end, the first end being connected to the first pump body; A high-precision regulating valve, one end of which is connected to the first chamber, the second end of the hydraulic oil tank, and the switching valve, and the other end of which is connected between the second chamber and the output end of the first pump body; The hydraulic actuator is driven by controlling the first drive device and the switching valve, and the speed, pressure and / or telescopic displacement of the drive rod are adjusted by controlling the first drive device and the high-precision regulating valve.

2. The hydraulic power device according to claim 1, characterized in that, It also includes a second drive unit and a second pump body. The second pump body is driven by the second drive unit. The second end of the hydraulic oil tank is connected to the first cavity. The second pump body is used to drive the hydraulic oil tank. A one-way valve is connected between the second pump body and the first cavity.

3. The hydraulic power device according to claim 2, characterized in that, By controlling the opening of the switching valve, controlling the complete closure of the high-precision regulating valve, and controlling the first driving device and the second driving device to drive the first pump body and the second pump body, the output end of the first pump body and the output end of the second pump body form a confluence and output to the first cavity, and the driving rod quickly retracts.

4. The hydraulic power device according to claim 3, characterized in that, A first relief valve is connected between the first end of the hydraulic oil tank and the output end of the switching valve and the first pump body.

5. The hydraulic power device according to claim 2, characterized in that, By controlling the switching valve to close, controlling the high-precision regulating valve to fully open, and controlling the first driving device and the second driving device to drive the first pump body and the second pump body, the output end of the first pump body drives the second chamber, the output end of the first chamber and the output end of the second pump body form a confluence and output to the high-precision regulating valve, and a differential circuit is formed between the high-precision regulating valve, the first chamber and the second chamber.

6. The hydraulic power device according to claim 5, characterized in that, A second overflow valve is connected between the first end of the hydraulic oil tank and the second chamber, and between the high-precision regulating valve.

7. The hydraulic power device according to claim 2, characterized in that, By controlling the switching valve to open and close the second pump body, and by controlling the first drive device to drive the first pump body, the first pump body, the second chamber, the first chamber and the switching valve sequentially form a circuit, and by controlling the high-precision regulating valve to adjust the amount of oil input to the second chamber.

8. The hydraulic power device according to claim 2, characterized in that, By controlling the high-precision regulating valve and the second pump body to close, and controlling the first driving device to drive the first pump body, the first pump body, the switching valve, the first chamber and the second chamber form a circuit in sequence, and the extension and retraction displacement of the driving rod is adjusted by controlling the first driving device.

9. The hydraulic power device according to any one of claims 1-8, characterized in that, A shuttle valve is connected between the first pump body and the first end of the hydraulic oil tank; the shuttle valve has two ends connected to the first pump body, namely a high-pressure end and a low-pressure end, and the low-pressure end is connected to the first end of the hydraulic oil tank.

10. The hydraulic power device according to any one of claims 1-8, characterized in that, The hydraulic actuator is connected to a displacement sensor, and a pressure sensor is connected between the second chamber and the high-precision regulating valve. The high-precision regulating valve is controlled by the detection results of the displacement sensor and the pressure sensor.

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