Hydraulic motor control system with stable start-stop and floating functions and control method
By optimizing the valve group combination of the hydraulic motor control system, the smooth start-stop and floating function of the hydraulic motor are realized, which solves the energy efficiency and stability problems of the traditional system under driven conditions and load changes, and improves the service life of the equipment and the stability of the rolling process.
Patent Information
- Application Number
- CN202511892964.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-02-27
AI Technical Summary
Traditional hydraulic motor control systems suffer from low energy efficiency, unstable operation, and severe start-stop shocks when facing driven conditions and complex load changes in strip mills, which affect equipment life and rolling quality.
The system employs a first hydraulically controlled check valve, a second hydraulically controlled check valve, a first check valve, a second check valve, a first balance valve, a second balance valve, a first shuttle valve, and a second shuttle valve, combined with a floating control valve group and a drive control valve group, to achieve smooth start-stop and floating function of the hydraulic motor. By using different valve groups in combination, energy recovery and load adaptation are optimized.
It improves the smoothness and resistance to load disturbances of hydraulic motors, reduces start-up and shutdown shocks, extends equipment life, and enhances energy utilization and rolling process stability.
Smart Images
Figure CN121576322A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of strip rolling, and particularly relates to a hydraulic motor control system and control method with smooth start-stop and floating functions. BACKGROUND
[0002] In a strip rolling mill system, a hydraulic motor is usually used as a driving device to provide stable power output for the rolling process. However, under certain process links or operating conditions, the load state will change significantly, for example, when the strip tension changes suddenly, the roll inertia drives, or the system decelerates and brakes, the hydraulic motor will change from a "driver" to a "driven", and enter a driven working condition. At this time, the reverse action of the load will push the hydraulic motor to run, so that it is actually in a pumping state, and the mechanical energy is converted into hydraulic energy. In a traditional hydraulic control circuit, the energy generated by the reverse dragging of this part often lacks an effective recycling or utilization path, and can only be discharged through a system preset overflow valve. Although the overflow valve can maintain the system pressure below the safety threshold to avoid equipment overload damage, it is essentially a passive way of consuming energy in the form of heat. In the long run, this not only leads to a significant increase in the energy consumption of the entire machine, but also causes the hydraulic oil temperature to rise sharply, resulting in a loss of control of the system thermal balance, and the need for additional powerful cooling devices, further increasing energy consumption and operating costs. At the same time, due to the hysteresis and pressure overshoot of the opening response of the overflow valve, when the driven working condition is transiently switched, it is easy to cause the system pressure to fluctuate sharply, causing hydraulic shock. This shock not only causes the running stability of the actuator to decline, affecting the thickness accuracy and surface quality of the strip rolling, but also transmits through the pipeline to the entire hydraulic system, causing component vibration and noise, accelerating the aging of the seal, the fatigue of the pipeline, and seriously damaging the service life and reliability of the hydraulic motor and other core components.
[0003] On the other hand, the traditional control loop for the start-stop control of the hydraulic motor relies on the neutral function of the reversing valve to achieve. Although this design is simple in structure and low in cost, it has inherent defects when switching actions. When the reversing valve moves away from the neutral position to the working position, or returns from the working position to the neutral position, the on-off of the oil circuit is often sudden, which will cause the flow to the hydraulic motor to change in steps, and then cause the motor speed and output torque to change suddenly, resulting in obvious start-stop impact. In the rolling process, the load itself has complex and variable characteristics, such as uneven thickness of the strip, material deformation resistance fluctuation, etc., which will form strong load disturbance. The neutral control mode of the traditional reversing valve has limited adjustment capability when facing rolling load fluctuation, and the system has poor load disturbance resistance performance, which can easily cause instability in the rolling process, directly affecting the product yield. In addition, under the driven working condition, if only the reversing valve is used to cut off the oil circuit to limit the motor being dragged, it may cause abnormally high pressure or cavitation due to the closed cavity, which aggravates the instability and risk of the system. In summary, the traditional system scheme with overflow valve energy dissipation and reversing valve neutral control as the core has obvious deficiencies in energy efficiency, running stability, impact suppression and equipment durability when dealing with the motor driven working condition in the strip rolling mill and complex load changes. It has become a key technical bottleneck restricting the upgrading of high-end rolling equipment to high efficiency, precision and long life. SUMMARY
[0004] In view of the above problems, the purpose of the present application is to provide a hydraulic motor control system and control method with smooth start-stop and floating function. The present application sets first hydraulic control check valve, second hydraulic control check valve, first check valve, second check valve, first balance valve, second balance valve, first shuttle valve and second shuttle valve, according to the different working state of the hydraulic motor, put into driving control or floating control, effectively provide the circuit energy efficiency, enhance the smoothness, prolong the service life of the motor. And realize the smooth start-stop of the hydraulic motor, reduce the hydraulic impact in the process of start-stop, improve the anti-load disturbance ability.
[0005] The technical scheme of the present application is: a hydraulic motor control system with smooth start-stop and floating function, comprising a hydraulic motor, a first hydraulic control check valve, a second hydraulic control check valve, a first check valve, a second check valve, a first shuttle valve, a second shuttle valve, a floating control valve group, a drive control valve group, a motor brake, an oil supply oil circuit, an oil return oil circuit and an oil drain oil circuit, the hydraulic motor is provided with an oil port A, an oil port B and an oil port C, the oil port C is connected with a drain port L of the oil drain oil circuit, the first hydraulic control check valve is provided with an oil port A1, an oil port B1 and an oil port X1, the oil port A1 is connected with the oil port A, the second hydraulic control check valve has an oil port A2, an oil port B2 and an oil port X2, the oil port A2 is connected with the oil port B, the oil port B2 is connected with the oil port B1, the oil port X2 is connected with the oil port X1 and the floating control valve group, the first check valve has an oil port A3 and an oil port B3, the oil port A3 is connected with the oil port A, the second check valve has an oil port A4 and an oil port B4, the oil port A4 is connected with the oil port B, the oil port B4 is connected with the oil port B3 and the floating control valve group, the first shuttle valve is provided with an oil port A5, an oil port B5 and an oil port X5, the oil port X5 is connected with the motor brake, the oil port B5 is connected with the floating control valve group, the second shuttle valve is provided with an oil port A6, an oil port B6 and an oil port X6, the oil port X6 is connected with the oil port A5, the oil port A6 is connected with the oil port A through a first balance valve, and the oil port B6 is connected with the oil port B through a second balance valve.
[0006] Further, the first balance valve and the second balance valve are respectively arranged between the hydraulic motor and the drive control valve group, the first balance valve is connected with the oil port A, and the second balance valve is connected with the oil port B.
[0007] Further, the floating control valve group comprises a pressure reducing valve and a two-position four-way electromagnetic reversing valve, the P port of the two-position four-way electromagnetic reversing valve is connected with the oil supply port P of the oil supply oil circuit through the pressure reducing valve, and the T port of the two-position four-way electromagnetic reversing valve is connected with the oil return port T of the oil return oil circuit.
[0008] Further, the floating control valve group is provided with a pressure sensor.
[0009] Further, the drive control valve group comprises a double check valve, a double hydraulic control check valve and a three-position four-way electromagnetic reversing valve, the T port of the three-position four-way electromagnetic reversing valve is connected with the oil return port T of the oil return oil circuit, and the P port of the three-position four-way electromagnetic reversing valve is connected with the oil supply port P of the oil supply oil circuit.
[0010] Further, the motor brake adopts a pressure loss braking mode, and the control oil circuit has a pressure state and a pressure loss state, corresponding to two working conditions of rotation freedom and brake retention of the hydraulic motor.
[0011] A hydraulic motor control method with smooth start-stop and floating function, using a hydraulic motor control system with smooth start-stop and floating function as described above, comprising the following steps: S1: when the electromagnet a or electromagnet b of the three-position four-way electromagnetic reversing valve of the drive control valve group is powered on in the working condition of driving the load, the high-pressure oil enters the motor brake through the drive control valve group, the second shuttle valve and the first shuttle valve, and the brake is released; the high-pressure oil is connected to the oil port A or oil port B of the hydraulic motor, at this time the first balance valve or the second balance valve forms back pressure on one side of the through oil port of the hydraulic motor, realizes the smooth start of the hydraulic motor, and drives the load to move; when the electromagnet a and electromagnet b of the three-position four-way electromagnetic reversing valve lose power, the hydraulic motor is smoothly braked under the back pressure of the first balance valve or the second balance valve, and remains in a stopped state under the action of the double hydraulic control check valve of the drive control valve group, at this time, the motor brake loses pressure through one of the two paths, and the motor brake is braked, one, the motor brake is connected to the return oil port T of the return oil circuit through the first shuttle valve, the floating control valve group and the return oil port T, and two, the motor brake is connected to the return oil port T of the return oil circuit through the first shuttle valve, the second shuttle valve, the drive control valve group and the return oil port T, in the above working condition, the electromagnet b of the two-position four-way electromagnetic reversing valve of the floating control valve group is powered on, and the floating function is not used; S2: when the hydraulic motor is operated by the load, the electromagnet a or electromagnet b of the three-position four-way electromagnetic reversing valve of the drive control valve group loses power, the electromagnet a of the two-position four-way electromagnetic reversing valve of the floating control valve group is powered on, the high-pressure oil enters the motor brake through the floating control valve group and the first shuttle valve, the brake is released, the high-pressure oil enters the oil port X1 of the first hydraulic control check valve and the oil port X2 of the second hydraulic control check valve, the first hydraulic control check valve and the second hydraulic control check valve are opened, the oil port A of the hydraulic motor is connected to the oil port B, and the hydraulic motor enters the floating state; the high-pressure oil enters the oil port B3 of the first check valve and the oil port B4 of the second check valve, opens the first check valve and the second check valve, and supplies oil to the hydraulic motor.
[0012] The technical effects of the present application are as follows: 1. The first hydraulic control check valve and the second hydraulic control check valve are provided, the oil port A and the oil port B of the hydraulic motor are connected, and the floating function of the hydraulic motor is realized; 2. The first check valve and the second check valve are provided, oil is supplied to the hydraulic motor in the floating state of the hydraulic motor, and the motor is prevented from being sucked; 3. The first balance valve and the second balance valve are provided, the smooth start-stop of the hydraulic motor is realized, the hydraulic impact in the start-stop process is reduced, and the anti-load disturbance ability is improved; 4. The first shuttle valve and the second shuttle valve are provided, the brake is released in the driving and floating state of the hydraulic motor.
[0013] Further description will be made below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS
[0014] Figure 1 This is a schematic diagram of the structure of a hydraulic motor control system with smooth start-stop and floating functions according to the present invention.
[0015] Reference numerals in the attached diagram: 1. Hydraulic motor; 2. First hydraulically controlled check valve; 3. Second hydraulically controlled check valve; 4. First check valve; 5. Second check valve; 6. First balance valve; 7. Second balance valve; 8. First shuttle valve; 9. Second shuttle valve; 10. Pressure sensor; 11. Pressure reducing valve; 12. Two-position four-way solenoid directional valve; 13. Double one-way throttle valve; 14. Double hydraulically controlled check valve; 15. Three-position four-way solenoid directional valve; 16. Motor brake; P is the oil supply port; T is the oil return port; L is the oil drain port. Detailed Implementation Example 1
[0016] like Figure 1 As shown, a hydraulic motor control system with smooth start / stop and floating functions includes a hydraulic motor 1, a first hydraulically controlled check valve 2, a second hydraulically controlled check valve 3, a first check valve 4, a second check valve 5, a first shuttle valve 8, a second shuttle valve 9, a floating control valve group, a drive control valve group, a motor brake 16, an oil supply circuit, an oil return circuit, and an oil drain circuit. The hydraulic motor 1 has ports A, B, and C, with port C connected to the drain port L of the oil drain circuit. The first hydraulically controlled check valve 2 has ports A1, B1, and X1, with port A1 connected to port A. The second hydraulically controlled check valve 3 has ports A2, B2, and X2, with port A2 connected to port B, and port B2 connected to port B... 1. The oil port X2 is connected to the oil port X1 and the floating control valve group. The first one-way valve 4 has oil port A3 and oil port B3, and oil port A3 is connected to oil port A. The second one-way valve 5 has oil port A4 and oil port B4, and oil port A4 is connected to oil port B. Oil port B4 is connected to oil port B3 and the floating control valve group. The first shuttle valve 8 has oil port A5, oil port B5 and oil port X5. Oil port X5 is connected to the motor brake 16. Oil port B5 is connected to the floating control valve group. The second shuttle valve 9 has oil port A6, oil port B6 and oil port X6. Oil port X6 is connected to oil port A5. Oil port A6 is connected to oil port A through the first balance valve 6. Oil port B6 is connected to oil port B through the second balance valve 7.
[0017] In use of the present application, the liquid control ports X1 and X2 of the first and second liquid control check valves 2 and 3 are communicated, when the floating control valve group is supplied with oil, the two valves are opened simultaneously to make the A port and the B port of the hydraulic motor 1 communicated, the motor enters the "free wheel" state, can be operated by the load in reverse, avoids high pressure or air suction in the closed dead space, and realizes the floating function; through the first and second check valves 4 and 5, the oil is supplied from the floating control valve group to the A port or the B port in the floating state, the cavitation or air suction caused by the rapid reverse rotation or the external load pulling of the motor is prevented, the oil supply in the floating state is realized, the first and second shuttle valves 8 and 9 constitute a double-path control logic, no matter driving or floating condition, as long as any oil path has pressure, the brake 16 can be released; the brake is automatically braked when the pressure is lost. Example 2
[0018] In the present embodiment based on the example 1, preferably, the first and second balance valves 6 and 7 are respectively arranged between the hydraulic motor 1 and the driving control valve group, the first balance valve 6 is communicated with the A port, and the second balance valve 7 is communicated with the B port.
[0019] In use of the present application, when the electromagnet a or the electromagnet b of the three-position four-way electromagnetic reversing valve 15 of the driving control valve group is electrified in the working condition of driving the load actively, the high-pressure oil liquid enters the motor brake 16 through the driving control valve group, the second shuttle valve 9, the first shuttle valve 8, the brake is released; the high-pressure oil is connected with the A port or the B port of the hydraulic motor 1, at this time, the first balance valve 6 or the second balance valve 7 forms the back pressure on one side of the through oil port of the hydraulic motor 1, realizes the stable starting of the hydraulic motor 1, and drives the load to move, the present application realizes the communication of the A port and the B port of the hydraulic motor through the arrangement of the first and second liquid control check valves, and completes the floating function of the hydraulic motor. Example 3
[0020] In the present embodiment based on the example 1 or the example 2, preferably, the floating control valve group comprises the pressure reducing valve 11 and the two-position four-way electromagnetic reversing valve 12, the P port of the two-position four-way electromagnetic reversing valve 12 is communicated with the oil supply port P of the oil supply oil path through the pressure reducing valve 11; the T port of the two-position four-way electromagnetic reversing valve 12 is communicated with the oil return port T of the oil return oil path.
[0021] In use of the present application, the pressure reducing valve 11 can reduce the pressure entering the control ports X1 and X2 of the liquid control check valves, avoids the liquid control check valves opened too fast or impacted due to the system pressure too high. The two-position four-way electromagnetic reversing valve 12 realizes the on-off control of the floating function, the electromagnet a is electrified to enter the floating mode, the electromagnet b is electrified to close the floating, the control is simple and fast in response. Example 4
[0022] In this embodiment, on the basis of embodiment 1 or embodiment 3, preferably, the floating control valve group oil circuit is provided with a pressure sensor 10.
[0023] When the application is used, the pressure sensor 10 monitors the pressure of the floating control oil circuit in real time, is used for setting the pressure of the pressure reducing valve during system debugging; monitors whether the hydraulic control check valve is normally opened during operation; and is used for fault diagnosis, such as alarming when the pressure is abnormal. Embodiment 5
[0024] In this embodiment, on the basis of embodiment 1 or embodiment 4, preferably, the drive control valve group comprises a double check throttle valve 13, a double hydraulic control check valve 14 and a three-position four-way electromagnetic reversing valve 15, the T port of the three-position four-way electromagnetic reversing valve 15 is in communication with the oil return port T of the oil return circuit, and the P port of the three-position four-way electromagnetic reversing valve 15 is in communication with the oil return port P of the oil supply circuit.
[0025] When the application is used, the double check throttle valve 13 can independently adjust the oil inlet and outlet speed of the motor forward and reverse rotation, realize smooth speed regulation, and adapt to different rolling speed requirements. The double hydraulic control check valve 14 locks the A and B oil circuits when the three-position four-way electromagnetic reversing valve 15 is in the middle position, prevents the motor from drifting due to external force or inertia, and maintains position accuracy. The three-position four-way electromagnetic reversing valve 15 realizes the drive control of the motor forward and reverse rotation, and the oil circuit is cut off when it is in the middle position. Embodiment 6
[0026] In this embodiment, on the basis of embodiment 1 or embodiment 5, preferably, the motor brake 16 adopts a pressure loss braking mode, and the control oil circuit thereof has a pressure state and a pressure loss state, corresponding to two working conditions of rotation freedom and braking retention of the hydraulic motor 1 respectively.
[0027] When the application is used, the control oil circuit of the motor brake 16 is in communication with the shuttle valve output, the brake is released when the pressure is high, and the brake is braked when the pressure is lost. The motor brake 16 can supply and discharge oil through the drive control valve group or the floating control valve group, thereby improving the reliability and safety of the system, and the motor brake 16 can still be braked when any valve group fails. Embodiment 7
[0028] A hydraulic motor control method with smooth start-stop and floating functions, using a hydraulic motor control system with smooth start-stop and floating functions as described above, comprising the following steps: S1: In the working condition of the hydraulic motor 1 driving the load, when the electromagnet a or the electromagnet b of the three-position four-way electromagnetic reversing valve 15 of the drive control valve group is powered on, the high-pressure oil respectively passes through the drive control valve group, the second shuttle valve 9 and the first shuttle valve 8 to enter the motor brake 16, and the brake is released; the high-pressure oil is connected with the oil port A or the oil port B of the hydraulic motor 1, at this time, the first balance valve 6 or the second balance valve 7 forms back pressure on one side of the through oil port of the hydraulic motor 1, so that the hydraulic motor 1 is started stably, and the load is driven to move; when the electromagnet a and the electromagnet b of the three-position four-way electromagnetic reversing valve 15 are powered off, the hydraulic motor 1 is stably braked under the back pressure of the first balance valve 6 or the second balance valve 7, and is kept in a stopped state under the action of the double hydraulic control check valve 14 of the drive control valve group, at this time, the motor brake 16 is de-pressurized through one of the two paths, and the motor brake is implemented, one, the motor brake 16 is connected with the return oil port T of the oil return oil circuit through the first shuttle valve 8 and the floating control valve group, two, the motor brake 16 is connected with the return oil port T of the oil return oil circuit through the first shuttle valve 8, the second shuttle valve 9 and the drive control valve group, in the above working condition, the electromagnet b of the two-position four-way electromagnetic reversing valve 12 of the floating control valve group is powered on, and the floating function is not used; S2: When the hydraulic motor 1 is reversely driven by the load, the electromagnet a or the electromagnet b of the three-position four-way electromagnetic reversing valve 15 of the drive control valve group is powered off, the electromagnet a of the two-position four-way electromagnetic reversing valve 12 of the floating control valve group is powered on, the high-pressure oil respectively passes through the floating control valve group and the first shuttle valve 8 to enter the motor brake 16, and the brake is released, the high-pressure oil enters the oil port X1 of the first hydraulic control check valve 2 and the oil port X2 of the second hydraulic control check valve 3, the first hydraulic control check valve 2 and the second hydraulic control check valve 3 are opened, the oil port A of the hydraulic motor 1 is connected with the oil port B, and the hydraulic motor 1 enters the floating state; the high-pressure oil enters the oil port B3 of the first check valve 4 and the oil port B4 of the second check valve 5, the first check valve 4 and the second check valve 5 are opened, and the hydraulic motor 1 is supplied with oil.
[0029] In the driving working condition, the electromagnet a or b of the three-position four-way electromagnetic reversing valve 15 is powered on, the high-pressure oil enters the motor brake 16 through the drive valve group, the second shuttle valve 9 and the first shuttle valve 8, and the brake is released. At the same time, the first balance valve 6 or the second balance valve 7 forms back pressure on one side of the through oil port of the hydraulic motor 1, so that the hydraulic motor 1 is started stably and accelerated stably. In the floating working condition, the brake is released through the floating control valve group, the first hydraulic control check valve 2 and the second hydraulic control check valve 3 are opened to make the motor enter the floating state, and the motor is supplied with oil through the check valve to prevent air suction. The present application can automatically switch the driving and floating modes according to the load state, improve the energy utilization rate and the running stability.
[0030] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.
Claims
1. A hydraulic motor control system with smooth start / stop and floating functions, characterized in that: The system includes a hydraulic motor (1), a first hydraulically controlled check valve (2), a second hydraulically controlled check valve (3), a first check valve (4), a second check valve (5), a first shuttle valve (8), a second shuttle valve (9), a floating control valve group, a drive control valve group, a motor brake (16), an oil supply circuit, an oil return circuit, and an oil drain circuit. The hydraulic motor (1) has ports A, B, and C. Port C is connected to the oil drain port L of the oil drain circuit. The first hydraulically controlled check valve (2) has ports A1, B1, and X1. Port A1 is connected to port A. The second hydraulically controlled check valve (3) has ports A2, B2, and X2. Port A2 is connected to port B, and port B2 is connected to port B1. X2 is connected to port X1 and the floating control valve group. The first check valve (4) has port A3 and port B3, and port A3 is connected to port A. The second check valve (5) has port A4 and port B4, and port A4 is connected to port B. Port B4 is connected to port B3 and the floating control valve group. The first shuttle valve (8) has port A5, port B5 and port X5. Port X5 is connected to the motor brake (16). Port B5 is connected to the floating control valve group. The second shuttle valve (9) has port A6, port B6 and port X6. Port X6 is connected to port A5. Port A6 is connected to port A through the first balance valve (6). Port B6 is connected to port B through the second balance valve (7).
2. The hydraulic motor control system with smooth start / stop and floating functions according to claim 1, characterized in that: The hydraulic motor (1) and the drive control valve group are respectively provided with a first balance valve (6) and a second balance valve (7). The first balance valve (6) is connected to oil port A, and the second balance valve (7) is connected to oil port B.
3. The hydraulic motor control system with smooth start / stop and floating functions according to claim 2, characterized in that: The floating control valve group includes a pressure reducing valve (11) and a two-position four-way solenoid directional valve (12). The P port of the two-position four-way solenoid directional valve (12) is connected to the oil supply port P of the oil supply circuit through the pressure reducing valve (11); the T port of the two-position four-way solenoid directional valve (12) is connected to the oil return port T of the oil return circuit.
4. A hydraulic motor control system with smooth start / stop and floating functions according to claim 3, characterized in that: A pressure sensor (10) is installed on the oil circuit of the floating control valve group.
5. A hydraulic motor control system with smooth start / stop and floating functions according to claim 4, characterized in that: The drive control valve group includes a double one-way throttle valve (13), a double hydraulic check valve (14), and a three-position four-way solenoid directional valve (15). The T port of the three-position four-way solenoid directional valve (15) is connected to the return port T of the return oil circuit, and the P port of the three-position four-way solenoid directional valve (15) is connected to the return port P of the supply oil circuit.
6. A hydraulic motor control system with smooth start / stop and floating functions according to claim 5, characterized in that: The motor brake (16) adopts the pressure loss braking mode. The pressurized and pressureless states of its control oil circuit correspond to the two working conditions of free rotation and brake holding of the hydraulic motor (1), respectively.
7. A hydraulic motor control method with smooth start-stop and floating functions, using the hydraulic motor control system with smooth start-stop and floating functions as described in claim 6, characterized in that: Includes the following steps: S1: When the hydraulic motor (1) is actively driving the load, and the electromagnet a or electromagnet b of the three-position four-way solenoid directional valve (15) of the drive control valve group is energized, the high-pressure oil enters the motor brake (16) through the drive control valve group, the second shuttle valve (9), and the first shuttle valve (8), respectively, and the brake is released; the high-pressure oil is connected to the oil port A or oil port B of the hydraulic motor (1), at which time the first balance valve (6) or the second balance valve (7) forms back pressure on one side of the return oil port of the hydraulic motor (1), realizing the smooth start of the hydraulic motor (1) and driving the load to move; when the electromagnets a and b of the three-position four-way solenoid directional valve (15) are de-energized, the hydraulic motor (1) in Under the back pressure of the first balance valve (6) or the second balance valve (7), the brake is smoothly applied and kept in a stopped state under the action of the double hydraulic check valve (14) of the drive control valve group. At this time, the motor brake (16) loses pressure through one of two paths, and the motor brake is implemented. First, the motor brake (16) is connected to the return port T of the return oil circuit through the first shuttle valve (8), the floating control valve group, and the return oil circuit, respectively. Second, the motor brake (16) is connected to the return port T of the return oil circuit through the first shuttle valve (8), the second shuttle valve (9), the drive control valve group, and the return oil circuit, respectively. Under the above conditions, the electromagnet b of the two-position four-way solenoid directional valve (12) of the floating control valve group is energized, and the floating function is not put into use. S2: When the hydraulic motor (1) is driven by the load, the solenoid a or solenoid b of the three-position four-way solenoid directional valve (15) of the drive control valve group is de-energized, and the solenoid a of the two-position four-way solenoid directional valve (12) of the floating control valve group is energized. The high-pressure oil enters the motor brake (16) through the floating control valve group and the first shuttle valve (8). When the brake is released, the high-pressure oil enters the oil port X1 of the first hydraulic control check valve (2) and the oil port X2 of the second hydraulic control check valve (3). The first hydraulic control check valve (2) and the second hydraulic control check valve (3) are opened, and the oil port A and oil port B of the hydraulic motor (1) are connected, and the hydraulic motor (1) enters the floating state. The high-pressure oil enters the oil port B3 of the first check valve (4) and the oil port B4 of the second check valve (5), opens the first check valve (4) and the second check valve (5), and replenishes the hydraulic motor (1) with oil.