Hydraulic braking system for load free fall operating condition of hoisting winch and its method of action

Abstract

The hydraulic brake system for the load-free falling working condition of the lifting hoist and the action method thereof belong to the field of engineering machinery. The system comprises a mechanical device and a hydraulic device. The system recovers the braking energy by storing the high-pressure oil liquid output by the hydraulic motor driven by the speed increaser into the accumulator at the free-falling terminal braking point, realizes rapid and reliable braking, and has stable braking, small heating, long service life and high reliability. When the power is lifted, the high-pressure oil liquid stored in the accumulator drives the hydraulic motor and the speed increaser to rotate, and the power mechanical drive unit jointly drives the winding drum to lift the load, realizes the reuse of the braking recovery energy, improves the system efficiency and reduces the energy consumption.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery, primarily to the hoisting mechanisms of geotechnical construction machinery such as dynamic compaction machines and continuous wall grab buckets. Through a hydraulic braking system, it achieves rapid and reliable braking of the drum at the end of the fall, as well as the recovery and reuse of braking energy, during the free-fall of a hoisting winch under load. It is also applicable to braking the drum of other equipment during free rotation. Background Technology

[0002] During the operation of geotechnical construction machinery such as dynamic compaction machines and continuous wall grab buckets, after the hoisting mechanism lifts the load to the predetermined height, the hoisting winch needs to be in a free-falling state without disengaging the hook. The load falls rapidly and freely, while the hoisting wire rope drives the drum to rotate at high speed. When the load falls to the predetermined height, i.e., the end point of the fall, the high-speed rotating drum needs to be braked quickly.

[0003] Conventional braking methods use disc brakes or band brakes along the drum edge. The disadvantages are high brake shoe heat generation, rapid wear, and poor braking effect; these are generally only used for braking unloaded freefall. Some methods employ imported dedicated reducers with freefall braking capabilities, which incorporate multi-disc, oil-cooled mechanical brakes within the hoisting reducer. The disadvantages are that these dedicated reducers are expensive, all drum kinetic energy is converted into heat through friction, resulting in high heat generation, and energy recovery is not possible. Summary of the Invention

[0004] This invention provides a hydraulic braking system that enables rapid and reliable braking, braking energy recovery, and reuse of the drum at the end of the fall when a hoisting winch is in free fall under load.

[0005] The technical solution adopted in this invention is:

[0006] The hydraulic braking system includes mechanical devices and hydraulic devices.

[0007] The mechanical device includes a mechanical drive unit 1 (hydraulic motor, electric motor or engine with hydraulic coupling), a reducer 2 and a clutch 3, a drum 4, and a speed increaser 5 connected in sequence.

[0008] The mechanical drive unit 1 reduces speed and increases torque through the reducer 2, and transmits power through the closed clutch 3 to drive the drum 4 to rotate, thereby realizing the lifting and lowering of the hoist.

[0009] When clutch 3 disengages, the power connection between reducer 2 and drum 4 is broken, allowing the hoisting winch to fall freely.

[0010] The shaft of drum 4 is connected to the input shaft of speed increaser 5. When drum 4 rotates, the output shaft of speed increaser 5 accelerates its rotation. Conversely, if a driving torque is applied to the output shaft of speed increaser 5, the input shaft of speed increaser 5 will drive drum 4 to rotate. The function of speed increaser 5 is to accelerate the high-speed rotating drum to a relatively high operating speed before braking during a free fall under load, allowing hydraulic motor 6 to reach a more efficient operating speed.

[0011] The hydraulic system includes a hydraulic motor 6, a hydraulic oil tank 7, a relief valve 8, a check valve 9, a first pilot-operated check valve 10, a second pilot-operated check valve 11, an accumulator 12, a first solenoid directional valve 13, a second solenoid directional valve 14, and a pressure transmitter 15. Port A of the hydraulic motor 6 is connected to port P of the relief valve 8, port B of the check valve 9, port B of the first pilot-operated check valve 10, and port A of the second pilot-operated check valve 11. Port B of the hydraulic motor 6 is connected to the hydraulic oil tank 7, port T of the relief valve 8, port A of the check valve 9, and port A of the first pilot-operated check valve 10. Port B of the second pilot-operated check valve 11 is connected to the accumulator 12 and the pressure transmitter 15. Ports P of the first solenoid directional valve 13 and the second solenoid directional valve 14 are connected to an external hydraulic power source of 3 MPa. Port A of the first solenoid directional valve 13 is connected to port C of the first pilot-operated check valve 10. The A port of the second solenoid directional valve 14 is connected to the C port of the second hydraulic check valve 11. The T port of the hydraulic motor, the T port of the first solenoid directional valve 13, and the T port of the second solenoid directional valve 14 are connected to the hydraulic oil tank 7.

[0012] The input shaft of the hydraulic motor 6 is connected to the output shaft of the speed increaser 5. When the speed increaser 5 drives the hydraulic motor 6 to rotate, the hydraulic motor 6, acting as a load on the speed increaser 5, is equivalent to the working condition of a hydraulic pump. When the hydraulic motor 6 drives the speed increaser 5, the speed increaser 5, acting as a load, is equivalent to the working condition of a speed reducer.

[0013] The hydraulic oil tank 7 stores hydraulic oil and is positioned at a high level to improve the oil suction conditions of the hydraulic motor 6.

[0014] The relief valve 8 provides a safety pressure limit for the pressure at port A of the hydraulic motor 6.

[0015] When the electromagnet of the first solenoid directional valve 13 is de-energized, the pressure at port C of the first hydraulically controlled check valve 10 is zero, and the flow from port B to port A of the first hydraulically controlled check valve 10 is cut off. When the electromagnet of the first solenoid directional valve 13 is energized, the pressure at port C of the first hydraulically controlled check valve 10 is 3 MPa, and the flow from port B to port A of the first hydraulically controlled check valve 10 is open.

[0016] When the electromagnet of the second solenoid directional valve 14 is de-energized, the pressure at port C of the second hydraulic check valve 11 is zero, and the flow from port B to port A of the second hydraulic check valve 11 is cut off. When the electromagnet of the second solenoid directional valve 14 is energized, the pressure at port C of the second hydraulic check valve 11 is 3 MPa, and the flow from port B to port A of the second hydraulic check valve 11 is open.

[0017] When the hydraulic motor 6 rotates in reverse (oil inlet at port B, oil outlet at port A), if the flow from port B to port A of the first hydraulically controlled check valve 10 is open, the oil outlet from port A of the hydraulic motor 6 flows back to the hydraulic oil tank 7 via the flow from port B to port A of the first hydraulically controlled check valve 10. If the flow from port B to port A of the first hydraulically controlled check valve 10 is cut off, the oil outlet from port A of the hydraulic motor 6 enters the accumulator 12 for charging via the flow from port A to port B of the second hydraulically controlled check valve 11.

[0018] When the hydraulic motor 6 rotates forward (oil inlet at port A, oil outlet at port B), if the flow from port B to port A of the second hydraulically controlled check valve 11 is open, the high-pressure oil in the accumulator 12 enters the port A of the hydraulic motor 6 through the port B to port A of the second hydraulically controlled check valve 11, driving the hydraulic motor 6 to rotate forward. If the flow from port B to port A of the second hydraulically controlled check valve 11 is cut off, the hydraulic motor 6 draws oil into port A, creating a vacuum. The oil in the oil tank 7 then replenishes the hydraulic motor 6's port A through the port A to port B of the check valve 9, preventing the hydraulic motor 6 from drawing in air.

[0019] Pressure transmitter 15 detects the oil filling pressure of accumulator 12.

[0020] Hydraulic schematic diagram as follows Figure 1 As shown.

[0021] The effects and benefits of this invention are:

[0022] During freefall braking, the drum drives a hydraulic motor via a speed increaser to output high-pressure oil, which is stored in an accumulator to recover braking energy and generate braking effect. The braking is smooth, generates little heat, has a long service life, and is highly reliable.

[0023] During power lifting, the high-pressure oil stored in the accumulator drives the hydraulic motor to rotate, and the hydraulic motor drives the speed increaser (equivalent to a speed reducer in this working condition), which in turn assists the mechanical drive unit to drive the drum to lift the load, realize the reuse of braking energy, reduce energy consumption and improve system efficiency. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the mechanical and hydraulic system of the present invention.

[0025] The diagram includes: a mechanical drive unit 1 (hydraulic motor, electric motor, or engine with hydraulic coupling), a reducer 2, a clutch 3, a drum 4, a speed increaser 5, a hydraulic motor 6, a hydraulic oil tank 7, an overflow valve 8, a check valve 9, a first hydraulically controlled check valve 10, a second hydraulically controlled check valve 11, an accumulator 12, a first solenoid directional valve 13, a second solenoid directional valve 14, and a pressure transmitter 15. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the technical solutions and accompanying drawings.

[0027] Power descent condition: Mechanical drive unit 1 reverses, and through reducer 2 and closed clutch 3, drives drum 4 to reverse, driving the load to decrease. Drum 4 is accelerated by speed increaser 5, driving hydraulic motor 6 to reverse (oil inlet at port B, oil outlet at port A). At this time, hydraulic braking is not required, so the electromagnet of the first solenoid directional valve 13 is energized and the electromagnet of the second solenoid directional valve 14 is not energized. Oil outlet at port A of hydraulic motor 6 flows to hydraulic oil tank 7 through port B of the first hydraulic control check valve 10. The pressure difference between port A and port B of hydraulic motor 6 is zero, and the torque driving hydraulic motor 6 is zero (efficiency not considered), which has no effect on power descent.

[0028] Free fall condition: Mechanical drive unit 1 stops, clutch 3 disengages, load accelerates free fall, drive drum 4 to reverse, drum 4 speeds up through speed increaser 5, drive hydraulic motor 6 to reverse (oil inlet at port B, oil outlet at port A). At this time, hydraulic braking is not required, so the electromagnet of the first solenoid directional valve 13 is energized and the electromagnet of the second solenoid directional valve 14 is de-energized. Oil outlet at port A of hydraulic motor 6 flows to hydraulic oil tank 7 through port B of the first hydraulic control check valve 10. The pressure difference between port A and port B of hydraulic motor 6 is zero, and the torque driving hydraulic motor 6 is zero (efficiency not considered), which has no effect on free fall.

[0029] Braking at the End of Free Fall: The load falls freely to the endpoint height. Mechanical drive unit 1 remains stationary, clutch 3 remains disengaged, the electromagnet of the first solenoid directional valve 13 is de-energized, the electromagnet of the second solenoid directional valve 14 is de-energized, and oil from port A of hydraulic motor 6 flows through port A to port B of the second hydraulic check valve 11 to charge accumulator 12, recovering braking energy. The pressure difference between port A and port B of hydraulic motor 6 is the charging pressure of the accumulator (increasing during the charging process). The torque driving hydraulic motor 6 is amplified by speed increaser 5, and its reaction force becomes the braking torque on the drum, achieving the braking function. If the charging pressure of accumulator 12 reaches the overflow pressure of overflow valve 8, accumulator 12 stops charging, and excess oil overflows back to hydraulic tank 7 through overflow valve 8. When the drum stops rotating, braking ends, and clutch 3 closes.

[0030] Power lifting operation: Mechanical drive unit 1 rotates forward, driving drum 4 to rotate forward via reducer 2 and closed clutch 3, lifting the load. Pressure transmitter 15 detects the oil pressure of accumulator 12. If there is pressure (meaning there is pressurized oil in accumulator 12), the electromagnet of the first solenoid directional valve 13 is de-energized, and the electromagnet of the second solenoid directional valve 14 is energized. The pressurized oil in accumulator 12 flows through port B to port A of the second hydraulic check valve 11, and then to port A of hydraulic motor 6, driving hydraulic motor 6 to rotate forward (oil inlet at port A, oil outlet at port B). The input shaft of hydraulic motor 6 drives the output shaft of speed increaser 5, reducing speed and increasing torque. The input shaft of speed increaser 5 drives drum to rotate forward, assisting the mechanical drive unit in jointly driving drum to lift the load, realizing the reuse of braking energy. When pressure transmitter 15 detects that the oil pressure of accumulator 12 is zero (meaning there is no pressurized oil in accumulator 12), the electromagnet of the second solenoid directional valve 14 is de-energized, and the assist ends.

Claims

1. A hydraulic braking system for a hoisting winch mechanism under load and free fall conditions, characterized in that, The hydraulic braking system includes a mechanical device and a hydraulic device; the mechanical device includes a mechanical drive unit (1), a reducer (2), a clutch (3), a drum (4), and a speed increaser (5) connected in sequence; the hydraulic device includes a hydraulic motor (6), a hydraulic tank (7), an overflow valve (8), a check valve (9), a first hydraulically controlled check valve (10), a second hydraulically controlled check valve (11), an accumulator (12), a first solenoid directional valve (13), a second solenoid directional valve (14), and a pressure transmitter (15); The mechanical drive unit (1) reduces speed and increases torque through the reducer (2), and transmits power through the closed clutch (3) to drive the drum (4) to rotate, thereby realizing the lifting and lowering of the hoist. When the clutch (3) is disengaged, the power connection between the reducer (2) and the drum (4) is disconnected, thereby realizing the free fall of the hoist. The shaft of the drum (4) is connected to the input shaft of the speed increaser (5), and the output shaft of the speed increaser (5) is connected to the input shaft of the hydraulic motor (6). The A port of the hydraulic motor (6) is connected to the P port of the relief valve (8), the B port of the check valve (9), the B port of the first hydraulically controlled check valve (10), and the A port of the second hydraulically controlled check valve (11); the B port of the hydraulic motor (6) is connected to the hydraulic oil tank (7), the T port of the relief valve (8), the A port of the check valve (9), and the A port of the first hydraulically controlled check valve (10); the B port of the second hydraulically controlled check valve (11) is connected to the accumulator (12) and the pressure transmitter (15); the P port of the first solenoid directional valve (13) and the P port of the second solenoid directional valve (14) are connected to the external control... The oil source is 3 MPa; the A port of the first electromagnetic directional valve (13) is connected to the C port of the first hydraulic control check valve (10); the A port of the second electromagnetic directional valve (14) is connected to the C port of the second hydraulic control check valve (11); the T port of the hydraulic motor (6), the T port of the first electromagnetic directional valve (13), and the T port of the second electromagnetic directional valve (14) are connected to the hydraulic oil tank (7); using the 3 MPa external control oil source, the first electromagnetic directional valve (13) controls the C port of the first hydraulic control check valve (10), and the second electromagnetic directional valve (14) controls the C port of the second hydraulic control check valve (11); The hydraulic oil tank (7) stores hydraulic oil and is placed at a high position to improve the oil suction conditions of the hydraulic motor (6); The relief valve (8) provides a safety pressure limit for the pressure at port A of the hydraulic motor (6); The pressure transmitter (15) detects the oil filling pressure of the accumulator (12); When the electromagnet of the first solenoid directional valve (13) is de-energized, the pressure at port C of the first hydraulic check valve (10) is zero, and the flow from port B to port A of the first hydraulic check valve (10) is cut off; when the electromagnet of the first solenoid directional valve (13) is energized, the pressure at port C of the first hydraulic check valve (10) is 3 MPa, and the flow from port B to port A of the first hydraulic check valve (10) is open. When the electromagnet of the second electromagnetic reversing valve (14) is de-energized, the pressure at port C of the second hydraulic control check valve (11) is zero, and the flow from port B to port A of the second hydraulic control check valve (11) is cut off; when the electromagnet of the second electromagnetic reversing valve (14) is energized, the pressure at port C of the second hydraulic control check valve (11) is 3 MPa, and the flow from port B to port A of the second hydraulic control check valve (11) is open. When the hydraulic motor (6) rotates in the reverse direction, that is, when oil enters through port B and exits through port A, if the flow from port B to port A of the first hydraulic control check valve (10) is open, the oil exiting through port A of the hydraulic motor (6) flows back to the hydraulic oil tank (7) through the flow from port B to port A of the first hydraulic control check valve (10); if the flow from port B to port A of the first hydraulic control check valve (10) is cut off, the oil exiting through port A of the hydraulic motor (6) enters the accumulator (12) for charging through the flow from port A to port B of the second hydraulic control check valve (11). When the hydraulic motor (6) rotates in the forward direction, that is, when oil enters through port A and exits through port B, if the flow from port B to port A of the second hydraulic control check valve (11) is open, the high-pressure oil in the accumulator (12) enters the port A of the hydraulic motor (6) through the port B to port A of the second hydraulic control check valve (11), driving the hydraulic motor (6) to rotate in the forward direction; if the flow from port B to port A of the second hydraulic control check valve (11) is cut off, the hydraulic motor (6) draws oil through port A to generate a vacuum, and the oil in the oil tank (7) replenishes the hydraulic motor (6) through the port A to port B of the check valve (9), preventing the hydraulic motor (6) from drawing air. Power reduction condition: The mechanical drive unit (1) reverses, and drives the drum (4) to reverse through the reducer (2) and the closed clutch (3), driving the load to decrease. The drum (4) increases speed through the speed increaser (5), driving the hydraulic motor (6) to reverse. At this time, oil enters through port B and exits through port A of the hydraulic motor (6). The electromagnet of the first electromagnetic reversing valve (13) is energized, and the electromagnet of the second electromagnetic reversing valve (14) is not energized. The oil exiting through port A of the hydraulic motor (6) flows to the hydraulic oil tank (7) through port B of the first hydraulic control check valve (10). The pressure difference between port A and port B of the hydraulic motor (6) is zero, and the torque driving the hydraulic motor (6) is zero, which has no effect on the power reduction. Free fall condition: The mechanical drive unit (1) stops, the clutch (3) disengages, the drum (4) reverses under the load, the load accelerates the free fall, the drum (4) speeds up through the speed increaser (5), and drives the hydraulic motor (6) to reverse. At this time, oil enters through port B and exits through port A of the hydraulic motor (6). The electromagnet of the first electromagnetic reversing valve (13) is energized, and the electromagnet of the second electromagnetic reversing valve (14) is not energized. The oil exiting through port A of the hydraulic motor (6) flows to the hydraulic oil tank (7) through port B of the first hydraulic control check valve (10). The pressure difference between port A and port B of the hydraulic motor (6) is zero, the torque driving the hydraulic motor (6) is zero, and it has no effect on the free fall. Braking condition at the end of free fall: When the load falls freely to the end height, the mechanical drive unit (1) remains stopped, the clutch (3) remains disengaged, the electromagnet of the first electromagnetic reversing valve (13) is de-energized, the flow from port B to port A of the first hydraulic control check valve (10) is cut off, the oil from port A of the hydraulic motor (6) is supplied to the accumulator (12) via port A to port B of the second hydraulic control check valve (11), and the braking energy is recovered. The torque of the hydraulic motor (6) is amplified by the speed increaser (5) and reacts as the braking torque on the drum (4) to achieve the braking function. If the oil filling pressure of the accumulator (12) reaches the overflow pressure of the overflow valve (8), the accumulator (12) will no longer be filled with oil, and the excess oil will overflow back to the hydraulic oil tank (7) through the overflow valve (8). When the drum (4) stops rotating, the braking ends and the clutch (3) closes. Power lifting operation: The mechanical drive unit (1) rotates forward, and drives the drum (4) to rotate forward through the reducer (2) and the closed clutch (3), lifting the load upward; the pressure transmitter (15) detects the oil pressure of the accumulator (12). If there is pressure, the electromagnet of the second electromagnetic reversing valve (14) is energized, and the pressure oil in the accumulator (12) flows from port B to port A of the second hydraulic control check valve (11) to port A of the hydraulic motor (6), driving the hydraulic motor (6) to rotate forward. At this time, oil enters through port A and exits through port B of the hydraulic motor (6). The input shaft of the hydraulic motor (6) drives the output shaft of the speed increaser (5), reducing speed and increasing torque. The input shaft of the speed increaser (5) drives the drum (4) to rotate forward, assisting the mechanical drive unit (1) to jointly drive the drum (4) to lift the load, realizing the reuse of braking energy; when the pressure transmitter (15) detects that the pressure is zero, the electromagnet of the second electromagnetic reversing valve (14) is de-energized, and the assistance ends.

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