Pressure common rail secondary regulation linear driving system

Abstract

This invention belongs to the field of hydraulic control technology, specifically a pressure common rail secondary regulation linear drive system. This invention's high and low pressure common rail system, by installing an accumulator, adds an intermediate pressure between the conventional high and low pressure levels, dividing the hydraulic system pressure into multiple levels. This solves the problem of large throttling losses in actuators under small and medium loads caused by the hydraulic system pressure only matching the highest load, thereby reducing some losses. At the same time, the use of secondary regulation pressure supply makes the hydraulic system more energy-efficient, significantly improving system efficiency.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic control technology, specifically a pressure common rail secondary adjustment linear drive system. Background Technology

[0002] In valve control systems, multiple actuators are supplied with oil by the same pump, and the flow is distributed through throttling, resulting in significant losses, especially when there are large differences in load between the actuators. In addition, the load is directly connected to the pump, and the power source often operates in an inefficient range due to rapidly changing loads. Using a common high- and low-pressure rail system divides the hydraulic system pressure into multiple levels, which solves the problem of large throttling losses for actuators with small and medium loads caused by the hydraulic system pressure only matching the highest load. However, hydraulic valves are still used for flow control, and the energy regeneration problem from low pressure to high pressure circuit is not solved, resulting in kinetic energy loss.

[0003] Secondary regulation loops can significantly improve system efficiency, but linear actuators are difficult to control in variable circuits. Such systems are often only suitable for rotary motor systems. Using a hydraulic transformer matching scheme can truly achieve matching of various system pressures and can also recover energy from the hydraulic system. However, a hydraulic transformer is essentially a combination of a hydraulic pump and a hydraulic motor, making its structure relatively complex. Furthermore, hydraulic transformers are not as efficient as electrical transformers. Using multi-chamber hydraulic cylinders for matching can achieve graded matching of system pressures, but actuator speed control still requires hydraulic valves, and achieving actuator force and power control is relatively difficult. Summary of the Invention

[0004] To address the problems of large throttling losses and difficulty in controlling actuators in current circuits, this invention provides a pressure common rail secondary regulation linear drive system.

[0005] The technical solution adopted in this invention is: a pressure common rail secondary adjustment linear drive system, including a power unit and its driven parallel-connected slewing system, boom system, stick system, bucket system, and pressure oil circuit; the power unit includes a speed-regulating motor, a one-way variable pump, a first relief valve, and an oil tank; the speed-regulating motor is connected to the one-way variable pump, the one-way variable pump has an external drain port connected to the oil tank, the oil inlet of the one-way variable pump is connected to the oil tank, the P port of the three-position four-way directional valve of the slewing system oil circuit and the oil inlet of the first relief valve are connected in parallel to the oil outlet of the one-way variable pump, and the oil outlet of the first relief valve is connected to... The oil tank is connected; the slewing system includes a three-position four-way directional valve, a two-way fixed displacement pump, and a slewing device; the two ports of the two-way fixed displacement pump are respectively connected to ports A and B of the three-position four-way directional valve, and the two-way fixed displacement pump and the slewing device are connected mechanically or by a coupling; the pressure oil circuit includes a high-pressure oil circuit, a medium-pressure oil circuit, and a low-pressure oil circuit arranged in parallel, each oil circuit is equipped with a switching valve, and the high-pressure oil circuit and the low-pressure oil circuit are connected by a second relief valve; the boom system is located in the high-pressure oil circuit, including a first two-position three-way directional valve, a first three-position four-way directional valve, a first pressure sensor, a second pressure sensor, and a hydraulic system. The bridge circuit includes valves VI (position 2), VII (position 2), VIII (position 2), and IX (position 2), as well as the I continuous variable motor and the I hydraulic motor-mechanical linear actuator. The B port of the I position 4-way directional valve is connected to the high-pressure oil circuit, the C port to the medium-pressure oil circuit, and the D port to the low-pressure oil circuit. The four valves in the hydraulic bridge circuit—VI (position 2), VII (position 2), VIII (position 2), and IX (position 2)—are connected in series. The A port of the I position 4-way directional valve is connected to the VI (position 2) and VII (position 2) two-way valves. Between the valves, one interface of the I continuous variable motor is connected between the VII-position two-way switch valve and the VIII-position two-way switch valve, with the pressure at this point detected by the II pressure sensor; the other interface is connected between the VI-position two-way switch valve and the IX-position two-way switch valve, with the pressure at this point detected by the I pressure sensor. The I-position three-way directional valve is connected between the VIII-position two-way switch valve and the IX-position two-way switch valve. The I continuous variable motor and the I hydraulic motor-mechanical linear actuator are connected. The boom system and bucket system use the same components and connection control methods as the boom system.

[0006] Furthermore, the first hydraulic motor-mechanical linear actuator includes a reducer, rolling bearings, balls, a nut, a lead screw, and a push rod. This actuator is a novel type of actuator. One side of the reducer is connected to the motor via a coupling, and the other side is connected to the lead screw via a coupling. The rolling bearings are fitted onto the lead screw, and the balls are fitted between the lead screw and the nut. The nut is connected to the push rod. The hydraulic motor drives the reducer, which in turn drives the lead screw to rotate. The lead screw causes the balls to push the nut to move linearly, thereby realizing the extension and retraction of the push rod and the speed of its movement.

[0007] Furthermore, the reducer can be a gear reducer or a belt reducer.

[0008] Furthermore, the electric motor is one of an AC asynchronous motor, a stepper motor, a DC motor, or a servo motor.

[0009] Furthermore, the pressure oil circuit includes a first two-way switch valve (position I), a second two-way switch valve (position IV), and a high-pressure accumulator connected to the high-pressure oil circuit; a second two-way switch valve (position II) on the medium-pressure oil circuit; a third two-way switch valve (position III), a second two-way switch valve (position V), and a low-pressure accumulator on the low-pressure oil circuit; the oil inlets of the two-way switch valves on the high-pressure, medium-pressure, and low-pressure oil circuits are connected in parallel with the P port of the three-position four-way directional valve and the first relief valve to the oil outlet of the unidirectional variable pump; the first two-way switch valve (position I) and the second two-way switch valve (position IV) are connected; the second two-way switch valve (position IV) is connected to the high-pressure accumulator; the second two-way switch valve (position III) and the second two-way switch valve (position V) are connected; and the second two-way switch valve (position V) is connected to the low-pressure accumulator.

[0010] The present invention has the following beneficial effects: This invention discloses a pressure common rail secondary regulation linear drive system. Specifically, it adopts the pressure common rail circuit principle and a variable hydraulic motor to form a secondary regulation circuit, realizing throttling-free speed regulation of the hydraulic system linear drive system. It also introduces hydraulic motor torque control, speed control, and power control into the linear drive system, solving the actuator pressure matching problem of the hydraulic system, greatly improving the energy efficiency of the hydraulic system, and retaining the advantages of high power-to-weight ratio and flow sharing of centralized power supply. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of a pressure common rail secondary regulation linear drive system in this embodiment of the present invention; Figure 2 This is a schematic diagram of a hydraulic motor-mechanical linear actuator.

[0013] Explanation of reference numerals in the attached diagram: 1-Speed-regulating motor; 2-One-way variable pump; 3-I relief valve; 4-Oil tank; 5-Three-position four-way directional valve; 6-Two-way fixed displacement pump; 7-Rotation device; 8-I-Two-position two-way switching valve; 9-II-Two-position two-way switching valve; 10-III-Two-position two-way switching valve; 11-II relief valve; 12-I-Two-position three-way directional valve; 13-I-Three-position four-way directional valve; 14-I pressure sensor; 15- 16-Pressure sensor II; 17-Pressure valve VI, 2-position two-way switch; 18-Pressure valve VII, 2-position two-way switch; 19-Pressure valve VIII, 2-position two-way switch; 20-Continuous variable motor I; 21-Hydraulic motor-mechanical linear actuator I; 22-Pressure valve II, 3-position three-way directional control valve; 23-Pressure valve II, 4-position four-way directional control valve; 24-Pressure sensor III; 25-Pressure sensor IV; 26-Pressure sensor X, 2-position two-way switch. Switching valve; 27-XⅠ Two-position two-way switching valve; 28-XⅡ Two-position two-way switching valve; 29-XⅢ Two-position two-way switching valve; 30-II Continuous variable motor; 31-II Hydraulic motor-mechanical linear actuator; 32-III Two-position three-way directional valve; 33-III Three-position four-way directional valve; 34-V Pressure sensor; 35-VI Pressure sensor; 36-XⅣ Two-position two-way switching valve; 37-XⅤ Two-position valve Two-way switching valve; 38-Two-way switching valve at position XVI; 39-Two-way switching valve at position XVII; 40-Continuous variable motor at position III; 41-Hydraulic motor at position III - mechanical linear actuator; 42-High-pressure accumulator; 43-Two-way switching valve at position IV; 44-Low-pressure accumulator; 45-Two-way switching valve at position V; 46-Reducer; 47-Rolling bearing; 48-Ball bearing; 49-Nut; 50-Lead screw; 51-Push rod. Detailed Implementation

[0014] 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, and 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.

[0015] The purpose of this invention is to solve the problem of large throttling losses in actuators under medium and small loads caused by the hydraulic system pressure only matching the highest load when using a high-low pressure common rail system. This reduces some of the losses, and at the same time, the use of secondary pressure supply adjustment makes the hydraulic system more energy-efficient and significantly improves system efficiency.

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] As attached Figure 1As shown, a pressure common rail secondary regulation linear drive system includes a power unit, a slewing system, a boom system, a stick system, a bucket system, a high-pressure accumulator, a low-pressure accumulator, and high-pressure, medium-pressure, and low-pressure oil circuits. The boom system, stick system, and bucket system are controlled in the same way and are connected in parallel to three pressure oil circuits with different pressures. The installation positions of the high-pressure and low-pressure accumulators constitute oil circuits with different pressure levels.

[0018] The power unit includes a speed-regulating motor 1, a one-way variable pump 2, a first relief valve 3, and an oil tank 4. The speed-regulating motor is one of the following: an AC asynchronous motor, a stepper motor, a DC motor, or a servo motor. The speed-regulating motor is connected to the one-way variable pump via a mechanical connection or a coupling. The one-way variable pump has an external drain port connected to the oil tank. The oil inlet of the one-way variable pump is connected to the oil tank. The P port of the three-position four-way directional valve 5 of the rotary system oil circuit and the oil inlet of the first relief valve 3 are connected in parallel to the oil outlet of the one-way variable pump 2. The oil outlet of the first relief valve 3 is connected to the oil tank 4.

[0019] The rotary system includes a three-position four-way directional valve 5, a two-way metering pump 6, and a rotary device 7. The two ports of the two-way metering pump 6 are connected to ports A and B of the three-position four-way directional valve 5, respectively. The two-way metering pump 6 and the rotary device 7 are connected mechanically or by a coupling. During operation, the rotation direction of the rotary device is changed by connecting the three-position four-way directional valve 5 to different positions.

[0020] The pressure oil circuit includes a first two-way switch valve 8, a second two-way switch valve 43, and a high-pressure accumulator 42 connected to the high-pressure oil circuit; a second two-way switch valve 9 on the medium-pressure oil circuit; and a third two-way switch valve 10, a second two-way switch valve 45, and a low-pressure accumulator 44 on the low-pressure oil circuit. The high-pressure and low-pressure oil circuits are connected by a second relief valve 11. The inlets of the two-way switch valves on the high-pressure, medium-pressure, and low-pressure oil circuits are connected in parallel with the P port of the three-position four-way directional valve 5 and the first relief valve 3 at the outlet of the unidirectional variable pump. The first two-way switch valve 8 and the fourth two-way switch valve 43 are connected, the fourth two-way switch valve 43 is connected to the high-pressure accumulator 42, the third two-way switch valve 10 and the fifth two-way switch valve 45 are connected, and the fifth two-way switch valve 45 is connected to the low-pressure accumulator 44. By opening and closing different two-position two-way switching valves, oil circuits with different pressures can be connected, thereby achieving control of different pressure levels of the actuator.

[0021] The boom system includes a first two-position three-way directional valve 12, a first three-position four-way directional valve 13, a first pressure sensor 14, a second pressure sensor 15, a sixth two-position two-way switching valve 16, a seventh two-position two-way switching valve 17, a eighth two-position two-way switching valve 18, an IX two-position two-way switching valve 19, a first continuous variable motor 20, and a first hydraulic motor-mechanical linear actuator 21. Port B of the first three-position four-way directional valve 13 is connected to the high-pressure oil circuit, port C is connected to the medium-pressure oil circuit, and port D is connected to the low-pressure oil circuit. In the hydraulic bridge circuit, the four valves, namely the second two-way switch valves of the sixth, seventh, eighth, and ninth positions, are connected in series. Port A of the first three-position four-way directional valve is connected between the second two-way switch valves of the sixth and seventh positions. One port of the first continuous variable motor is connected between the second two-way switch valves of the seventh and eighth positions, and the pressure at this point is detected by the second pressure sensor. The other port is connected between the second two-way switch valves of the sixth and ninth positions, and the pressure at this point is detected by the first pressure sensor. The first two-position three-way directional valve is connected between the second two-way switch valves of the eighth and ninth positions. The first continuous variable motor is connected to the first hydraulic motor-mechanical linear actuator.

[0022] The connection and control methods of the second hydraulic motor-mechanical linear actuator 31, the third pressure sensor 24, the fourth pressure sensor 25, the X-position two-way switch valve 26, the XI-position two-way switch valve 27, the XI-position two-way switch valve 28, the XIII-position two-way switch valve 29, the second continuous variable motor 30, and the second hydraulic motor-mechanical linear actuator 31 in the boom system are the same as those in the boom system. The connection and control methods of the third hydraulic motor-mechanical linear actuator 41, the third-position three-way directional valve 32, the third-position four-way directional valve 33, the V-position pressure sensor 34, the VI-position pressure sensor 35, the XIV-position two-way switch valve 36, the XV-position two-way switch valve 37, the XVI-position two-way switch valve 38, the XVII-position two-way switch valve 39, and the third continuous variable motor 40 in the bucket system are the same as those in the boom system.

[0023] like Figure 2 As shown, the hydraulic motor-mechanical linear actuator 21 includes a reducer 46, rolling bearings 47, balls 48, a nut 49, a lead screw 50, and a push rod 51. One side of the reducer is connected to the motor via a coupling, and the other side is connected to the lead screw via a coupling. The reducer can be a gear reducer or a belt reducer. The rolling bearings are mounted on the lead screw, and the balls are fitted between the lead screw and the nut. The nut is connected to the push rod. The hydraulic motor drives the reducer, which in turn drives the lead screw to rotate. The lead screw causes the balls to push the nut in a linear motion, thereby realizing the extension and retraction of the push rod and the speed of its movement.

[0024] When the system is working, for the rotary device, when the three-position four-way directional valve is in the middle position, the rotary device does not operate. When the three-position four-way directional valve is in the two-side position, the rotary device rotates left and right. The rotation speed is related to the pump displacement.

[0025] Taking boom operation as an example, the working principle of the other two actuators is the same. In the working state, the system flow is from different pressure circuits through the first three-position four-way directional valve. When the second two-way switch valve is open and the second two-way switch valve is closed, the pressurized oil flows in from the upper oil port of the first continuous variable motor. When the second two-way switch valve is open, the oil flows out through the first two-position three-way directional valve. When the second two two-way switch valve is open and the second two two-way switch valve is closed, the pressurized oil flows in from the lower oil port of the first continuous variable motor. When the second two two-way switch valve is open, the oil flows out through the first two-position three-way directional valve. When the first two three-way directional valve is in the left working position, the pressurized oil flows into the oil circuit where the low-pressure accumulator is located. When it is in the right working position, the pressurized oil flows back to the oil tank. This is to realize the extension or retraction of the actuator and the speed of the action.

[0026] Operating Mode 1: When the load is at its maximum, the two-way switch valve at position I and position IV opens, and the four-way directional valve at position I and position III is connected to the left. The high-pressure accumulator keeps the oil in this circuit at a high pressure level, providing pressurized oil to the system. The three-way directional valve at position I and position III is connected to the left, and the oil flows back to the oil tank.

[0027] Operating Mode 2: When the load is large, the second position two-way switch valve II opens, the third position four-way directional valve I is connected to the middle position, the one-way variable pump provides pressure oil to the system, and the second position three-way directional valve I is connected to the left side, and the oil flows back to the oil tank.

[0028] Operating Mode 3: When the load is small, the second position of valve III and the second position of valve V are open, and the third position of valve I is connected to the right side. The low-pressure accumulator keeps the oil in this circuit at a low pressure level to provide pressurized oil to the system. The second position of valve I is connected to the left side, and the oil flows back to the oil tank.

[0029] Operating Mode 4: When the load is very small, using a pump to supply oil to the actuator cannot keep the pump in its high-efficiency operating range. At this time, the second position two-way switch valve II opens, the third position four-way directional valve I is connected to the middle position, the unidirectional variable pump supplies pressurized oil to the system, and the second position three-way directional valve I is connected to the right side, so the oil flows back to the low-pressure accumulator. By reducing the pressure difference between the two ports of the first continuous variable motor, the pump can supply oil normally and operate in a high-efficiency state, which increases the displacement of the motor and thus speeds up the action speed of the actuator.

[0030] When multiple actuators are working, the working principle is the same as when only one actuator is working. Depending on the different load requirements, the actuators select different pressure circuits through three-position four-way directional valves to work.

[0031] The oil ports B, C, and D of the three-way four-way directional valves 13 (position 1), 23 (position 2), and 33 (position 3) are arranged sequentially from left to right at the bottom.

Claims

1. A pressure common rail secondary regulation linear drive system, characterized in that: Includes the power unit and its parallel-connected slewing system, boom system, stick system, bucket system, and hydraulic system; The power unit includes a speed-regulating motor (1), a one-way variable pump (2), a first overflow valve (3), and an oil tank (4); the speed-regulating motor is connected to the one-way variable pump, the one-way variable pump has an external oil drain port connected to the oil tank, the oil inlet of the one-way variable pump is connected to the oil tank, the P port of the three-position four-way directional valve of the rotary system oil circuit and the oil inlet of the first overflow valve are connected in parallel to the oil outlet of the one-way variable pump, and the oil outlet of the first overflow valve is connected to the oil tank; The rotary system includes a three-position four-way directional valve (5), a two-way metering pump (6), and a rotary device (7); the two ports of the two-way metering pump are respectively connected to the A port and the B port of the three-position four-way directional valve, and the two-way metering pump and the rotary device are connected mechanically or by a coupling. The pressure oil circuit includes a high-pressure oil circuit, a medium-pressure oil circuit, and a low-pressure oil circuit arranged in parallel. Each oil circuit is equipped with a switch valve. The high-pressure oil circuit and the low-pressure oil circuit are connected by the second relief valve (11). The boom system is located in the high-pressure oil circuit and includes a first two-position three-way directional valve (12), a first three-position four-way directional valve (13), a first pressure sensor (14), a second pressure sensor (15), a sixth two-position two-way switching valve (16), a seventh two-position two-way switching valve (17), a eighth two-position two-way switching valve (18), an IX two-position two-way switching valve (19), a first continuous variable motor (20), and a first hydraulic motor-mechanical linear actuator (21). The first three-position four-way directional valve has port B connected to the high-pressure oil circuit, port C connected to the medium-pressure oil circuit, and port D connected to the low-pressure oil circuit. The sixth two-position two-way switching valve and the seventh two-position two-way switching valve in the hydraulic bridge circuit are also included. The four valves, namely the second two-way switch valve (VIII) and the second two-way switch valve (IX), are connected in series. Port A of the third three-way four-way directional valve (I) is connected between the second two-way switch valve (VI) and the second two-way switch valve (VII). One port of the first continuous variable motor is connected between the second two-way switch valve (VII) and the second two-way switch valve (VIII), and the pressure at this port is detected by the second pressure sensor (II). The other port is connected between the second two two-way switch valve (VI) and the second two two-way switch valve (IX), and the pressure at this port is detected by the first pressure sensor (I). The second three-way directional valve (I) is connected between the second two two-way switch valve (VIII) and the second two two-way switch valve (IX). The first continuous variable motor and the first hydraulic motor-mechanical linear actuator are connected. The boom system and bucket system use the same components and connection control methods as the boom system.

2. The pressure common rail secondary adjustment linear drive system according to claim 1, characterized in that: The first hydraulic motor-mechanical linear actuator (21) includes a reducer (46), a rolling bearing (47), a ball (48), a nut (49), a lead screw (50), and a push rod (51). One side of the reducer is connected to the motor via a coupling, and the other side is connected to the lead screw via a coupling. The rolling bearing is sleeved on the lead screw, the ball is fitted between the lead screw and the nut, and the nut is connected to the push rod. The hydraulic motor drives the reducer, the reducer drives the lead screw to rotate, and the lead screw causes the ball to push the nut to move linearly, thereby realizing the extension and retraction of the push rod and the speed of the action.

3. The pressure common rail secondary adjustment linear drive system according to claim 2, characterized in that: The speed reducer is a gear reducer or a belt reducer.

4. The pressure common rail secondary adjustment linear drive system according to claim 1, characterized in that: The speed-regulating motor (1) is one of AC asynchronous motor, stepper motor, DC motor and servo motor, and is connected to the unidirectional variable pump (2) by mechanical connection or coupling.

5. The pressure common rail secondary adjustment linear drive system according to claim 1, characterized in that: The pressure oil circuit includes a first two-way switch valve (8), a second two-way switch valve (43), and a high-pressure accumulator (42) connected to the high-pressure oil circuit; a second two-way switch valve (9) connected to the medium-pressure oil circuit; a third two-way switch valve (10), a second two-way switch valve (45), and a low-pressure accumulator (44) connected to the low-pressure oil circuit; the oil inlets of the two-way switch valves in the high-pressure, medium-pressure, and low-pressure oil circuits are connected in parallel with the P port of the three-position four-way directional valve and the first relief valve to the oil outlet of the unidirectional variable pump; the first two-way switch valve and the second two-way switch valve are connected; the second two-way switch valve is connected to the high-pressure accumulator; the third two-way switch valve and the second two-way switch valve are connected; and the second two-way switch valve is connected to the low-pressure accumulator.

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