CN-121251641-B - Closed pump control hydraulic circuit, self-adaptive flow compensation system and control method thereof

CN121251641BCN 121251641 BCN121251641 BCN 121251641BCN-121251641-B

Abstract

The invention relates to the technical field of closed pump control hydraulic pressure, in particular to a closed pump control hydraulic circuit, a self-adaptive flow compensation system and a control method thereof. The closed pump control hydraulic circuit comprises a piston assembly formed by two synchronously movable piston rods, the piston assembly is arranged in the main hydraulic cylinder and the self-adaptive flow compensator to form an integrated unit, the main hydraulic cylinder and the self-adaptive flow compensator are connected through a third electromagnetic switch switching valve, a compensation hydraulic circuit for the closed pump control main hydraulic cylinder can be formed, and when the closed pump control hydraulic circuit works under a four-quadrant working condition, the absorption and compensation for asymmetric flow in the main hydraulic cylinder are formed. The invention fundamentally solves the structural problem of asymmetric flow of the single-rod hydraulic cylinder in the closed pump control hydraulic system, and does not need to rely on complex auxiliary devices or special pump body designs with high difficulty, thereby having great significance in improving the reliability of the system, reducing the cost and optimizing the control performance.

Inventors

DING RUQI
YANG FENGYUAN
Xu Yinjing
XIA SHIQI
JIANG YOUPENG
XIA YIMIN
GAN BAOLIAN
ZHONG HUI
LI GANG
PENG LING

Assignees

华东交通大学
中南大学

Dates

Publication Date: 20260508
Application Date: 20251021

Claims (9)

1. A closed pump-controlled hydraulic circuit, comprising: A master cylinder (101) having a first chamber; The self-adaptive flow compensator (102) is arranged on the surface of the main hydraulic cylinder body (101), the self-adaptive flow compensator (102) is provided with a second containing cavity, and the first containing cavity and the second containing cavity are not communicated with each other and have unequal volumes; A piston assembly (103) having two synchronously movable piston rods respectively mounted within the master cylinder body (101) and the adaptive flow compensator (102) to form an adaptive flow compensation actuator unit (1), wherein the first volume is divided into a master cylinder rod-containing chamber and a master cylinder rod-free chamber based on the piston rods, and the second volume is divided into an adaptive flow compensator hydraulic chamber and an adaptive flow compensator atmosphere chamber; a hydraulic pump motor (2) having a first oil port (A) and a second oil port (B); a first electromagnetic switch switching valve (3) which is connected with the first oil port (A) and the rodless cavity of the main hydraulic cylinder; a second electromagnetic switch switching valve (4) which is connected with the second oil port (B) and the rod cavity of the main hydraulic cylinder to form a closed pump control main hydraulic circuit; The third electromagnetic switch switching valve (5), its oil return port (T) with the master cylinder does not have the pole chamber and is connected, and work port (A) with self-adaptation flow compensator hydraulic pressure chamber is connected, and oil feed mouth (P) with second hydraulic fluid port (B) are connected in order to form closed pump accuse compensation hydraulic circuit, when being in four-quadrant operating mode during operation, satisfy the difference in area (A1) of master cylinder does not have the pole chamber and area (A2) of master cylinder has the pole chamber equals area (A3) of self-adaptation flow compensator hydraulic pressure chamber to form the absorption and the compensation to the asymmetric flow in the master cylinder body (101).
2. The closed pump control hydraulic circuit according to claim 1, wherein the main hydraulic cylinder body (101) is a single-rod hydraulic cylinder, and the cross section of the self-adaptive flow compensator (102) is crescent-shaped and is tightly attached to the main hydraulic cylinder body (101).
3. The closed pump control hydraulic circuit according to claim 1, wherein a notch (F) is arranged at the bottom of the atmospheric chamber of the adaptive flow compensator, and a filter screen is arranged at the notch (F).
4. The closed pump-controlled hydraulic circuit of claim 1, further comprising an oil replenishment assembly for replenishing leaked oil to maintain absolute stability of a closed system oil replenishment pressure, the oil replenishment assembly comprising: A first pressure sensor (6) is arranged between the rodless cavity of the main hydraulic cylinder and the first electromagnetic switch switching valve (3); a second pressure sensor (7) is arranged between the rod cavity of the main hydraulic cylinder and the second electromagnetic switch switching valve (4); And the low-pressure energy accumulator (8) is communicated with the first electromagnetic switch switching valve (3) to form a first oil supplementing channel, and the low-pressure energy accumulator (8) is communicated with the second electromagnetic switch switching valve (4) to form a second oil supplementing channel.
5. The closed pump control hydraulic circuit according to claim 4, wherein a first check valve (9) and a second check valve (10) are provided on the first and second oil supplementing channels, respectively.
6. An adaptive flow compensation system, comprising: the closed pump-controlled hydraulic circuit according to any one of claims 1 to 5; a motor generator (14) coaxially connected to the hydraulic pump motor (2); And a hybrid energy recovery system (15) connected with the motor generator (14) for supplying energy to the closed pump-controlled hydraulic circuit or recovering electric energy of the motor generator (14) for storage.
7. A method for controlling an adaptive flow compensation system, wherein the adaptive flow compensation system according to claim 6 is used for controlling a hydraulic cylinder for a load, comprising the steps of: acquiring the displacement direction of a load and a piston assembly, and judging the instruction speed of the piston assembly based on the displacement direction; Acquiring the pressure P1 of a rodless cavity of the master hydraulic cylinder and the pressure P2 of a rod cavity of the master hydraulic cylinder, and judging the working conditions of the system based on the pressures P1 and P2 and the instruction speed of a piston assembly, wherein the working conditions comprise an impedance extension working condition, an impedance retraction working condition, an overrunning extension working condition and an overrunning retraction working condition; based on the working conditions, executing a corresponding control strategy to realize external work or energy recovery.
8. The adaptive flow compensation system control method of claim 7, wherein the executing the corresponding control strategy based on the operating condition comprises: If the hydraulic pump is in the impedance extension working condition, the hydraulic pump motor is switched to a pumping mode, the first electromagnetic switch valve is arranged at the right position, the second electromagnetic switch valve is arranged at the left position, the third electromagnetic switch valve is arranged at the right position, and the motor generator drives the hydraulic pump to operate; if the hydraulic pump motor is in the impedance retraction working condition, the hydraulic pump motor is switched to a pumping mode, the first electromagnetic switch valve is arranged at the right position, the second electromagnetic switch valve is arranged at the left position, the third electromagnetic switch valve is arranged at the left position, and the motor generator drives the hydraulic pump to operate.
9. The adaptive flow compensation system control method of claim 8, wherein the executing the corresponding control strategy based on the operating conditions further comprises: If the hydraulic pump motor is in the overrunning and extending working condition, the hydraulic pump motor is switched to a motor mode, the first electromagnetic switch switching valve is arranged at the right position, the second electromagnetic switch switching valve is arranged at the left position, the third electromagnetic switch switching valve is arranged at the right position, and the motor generator recovers the rotation energy of the hydraulic pump motor and converts the rotation energy into electric energy to be stored in the storage battery and the super capacitor; If the hydraulic pump motor is in the overrunning retraction working condition, the hydraulic pump motor is switched to a motor mode, the first electromagnetic switch switching valve is arranged at the right position, the second electromagnetic switch switching valve is arranged at the left position, the third electromagnetic switch switching valve is arranged at the right position, and the motor generator recovers the rotation energy of the hydraulic pump motor and converts the rotation energy into electric energy to be stored in the storage battery and the super capacitor.

Description

Closed pump control hydraulic circuit, self-adaptive flow compensation system and control method thereof Technical Field The invention relates to the technical field of closed pump control hydraulic pressure, in particular to a closed pump control hydraulic circuit, a self-adaptive flow compensation system and a control method thereof. Background The electrohydraulic control system is mainly divided into two technical routes of pump control and valve control. The valve control system is widely applied in the scene of strict dynamic performance requirements by virtue of the quick response characteristic and high-precision control capability, but a core control element, namely the multi-way valve, has an unavoidable throttling effect in the working process, so that the energy loss of the system is obviously increased, the energy utilization efficiency is low, and the inherent defect limits the application of the valve control system in the field with higher energy-saving requirements. Compared with the prior art, the pump control system adopts a topological structure of directly coupling the hydraulic pump and the hydraulic cylinder, and directly controls the output characteristics of the hydraulic cylinder by regulating and controlling the core parameters such as the displacement, the rotating speed and the like of the hydraulic pump, so that the energy loss generated by throttling in the valve control system is fundamentally eliminated, and the energy utilization rate of the system is obviously improved. However, when a single rod hydraulic cylinder is equipped in a traditional closed pump control system, the effective acting areas of a rod cavity and a rodless cavity have irreducible inherent differences, the differences are always kept constant, and the asymmetry on the areas can cause serious flow unbalance problem that under the same working condition, the theoretical discharge flow of the rodless cavity and the theoretical suction flow of the rod cavity cannot be balanced, so that obvious deviation occurs to the inlet and outlet flow of the whole hydraulic circuit, and the problem becomes a key bottleneck for restricting the improvement of the system performance. In response to this problem, the existing closed pump control hydraulic system has the following short plates: 1. Patent number [202210816720.X ] discloses [ a distributed independent variable speed closed pump control hydraulic system for an excavator ]. The system consists of four pump control hydraulic subsystems, wherein the first hydraulic pump and the second hydraulic pump adopt four-quadrant asymmetric quantitative hydraulic pumps to realize inlet and outlet flow balance, the third hydraulic pump and the fourth hydraulic pump are four-quadrant symmetric quantitative hydraulic pumps, and an oil supplementing system consisting of an energy accumulator and a one-way valve is needed to supplement oil so as to solve the problem of asymmetric flow of two cavities of an inlet and an outlet. On the one hand, the asymmetric three-port pump compensates the flow difference through a special flow distribution design, but the pump body faces huge technical problems in the aspects of curved surface flow distribution plate processing, three-port pressure matching, dynamic sealing and the like, has high design and manufacturing cost, greatly reduces the volumetric efficiency in a high-pressure environment, and is difficult to meet the requirement of large-scale application. On the other hand, an auxiliary oil supplementing loop consisting of a low-pressure energy accumulator, a hydraulic control one-way valve, an oil supplementing/draining valve group and the like is additionally arranged to adjust the flow difference, and although contradiction can be relieved to a certain extent, the additional hydraulic elements and control logic not only improve the integration difficulty of the system, but also can cause unstable pressure due to untimely oil supplementing and influence the control precision of the system. 2. Patent number [202310324055.7] discloses a multi-cylinder split combined type four-cavity hydraulic cylinder system, namely a multi-cylinder split combined type four-cavity hydraulic cylinder system which is capable of adjusting flow by means of cooperative combination of a plurality of independent two-cavity cylinders, and although the problem of flow asymmetry can be attempted to be solved by designing the effective acting area of each cavity/each cylinder, common defects are that the multi-cylinder split type hydraulic cylinder system is loose in multi-cylinder split type structure layout, low in space utilization rate, not only lacks compactness, but also is difficult to consider economical efficiency. 3. The patent number [202411110052.4] discloses a potential energy recovery system and a control method of a heavy-load pressing device, and the scheme adopts an integrated four-cavity hydraulic cylinder, so that the volume of an actuator is