WO2020248406A1

WO2020248406A1 - Constant decelerating hydraulic system for safe shifting braking of hoister and braking method

Info

Publication number: WO2020248406A1
Application number: PCT/CN2019/105023
Authority: WO
Inventors: 孙正; 张晓光; 徐文涛; 徐桂云; 蒋奇; 孙佳胜; 张春梅; 侯建华; 李辉; 郭学军
Original assignee: 枣庄学院; 徐州大恒测控技术有限公司; 山西霍宝干河煤矿有限公司
Priority date: 2019-06-10
Filing date: 2019-09-10
Publication date: 2020-12-17
Also published as: CN110219836B; CN110219836A

Abstract

A constant decelerating hydraulic system for the safe shifting braking of a hoister, comprising an oil tank (1), a motor (2), a variable displacement pump (3), an electromagnetic proportional overflow valve (4), a check valve, an energy accumulator, an electromagnetic overflow valve (7), pressure reducing valves, a damper brake set (12), a plurality of electromagnetic reversing valves, and an electromagnetic proportional reversing valve (G5). A braking method for the constant decelerating hydraulic system for the safe shifting braking of the hoister. A circumstance in which the pressure of the energy accumulator rapidly increases during a braking process and a hoisting system is impacted is avoided by means of different reversing operations of the electromagnetic proportional reversing valve (G5), the oil pressure of the damper brake set (12) is linearly and slowly reduced, and the stable deceleration a hoisting container is maintained. When constant decelerating fails, second-stage braking is immediately performed, and a first pressure reducing valve (8.1) and a second pressure reducing valve (8.2) which are provided are used to ensure that the pressure of the hoisting system is first reduced to the set second-stage braking oil pressure value at the stable speed, such that the hoister is in a semi-braking state; and after a period of time, the pressure is reduced to zero to achieve complete braking. The foregoing braking mode may prevent a circumstance in which the hoisting system is impacted by second-stage braking after the constant decelerating braking function fails, and braking reliability is thus ensured.

Description

Hydraulic system and braking method for safe conversion braking and constant deceleration of hoist

Technical field

The invention relates to a safe conversion braking constant deceleration hydraulic station suitable for emergency braking of a hoist, in particular to a hoist safe conversion braking constant deceleration hydraulic system and a braking method, belonging to the technical field of mine hoists.

Background technique

In the coal mine production system, the mine hoisting system is an important part of ensuring the normal operation of the mine, and the reliability of the braking system directly affects the safe operation of the mine hoisting equipment.

At present, most of the brake systems used by hoists are hydraulic disc brakes, and the brakes are divided into working brakes and safety brakes. Working brake only adjusts the power supply voltage of the proportional relief valve and then adjusts the oil pressure of the disc brake to realize the start and stop of the hoist; the safety brake is divided into constant deceleration braking, primary braking and secondary braking. Dynamic, constant deceleration braking is to adjust the proportional reversing valve or proportional servo valve to adjust the oil pressure of the disc brake by monitoring the closed loop feedback of the hoist speed, so that the brake shoe slowly locks the brake disc and maintains the deceleration Within a stable range; the first level of braking is to adjust the oil pressure of the two sets of disc brakes to zero, and directly lock the brake discs with the maximum braking torque; the second level of braking is to apply the disc brakes first The oil pressure adjustment is reduced to a two-stage brake pressure value, and then the oil pressure value is reduced to zero, and braking is performed through the two-stage oil pressure.

However, most of the secondary brake oil pressure values are given when the hydraulic station is installed. After the constant deceleration fails, no matter how great the oil pressure in the brake is, the secondary brake will stabilize the oil pressure at a constant level. Set value, which will cause the constant deceleration to fail and switch to the secondary braking process. Due to the replenishment of the accumulator, the oil pressure may rise, which will impact the lifting system and increase the risk of rope breaking. Come security incident.

Summary of the invention

In order to overcome various deficiencies in the prior art, the present invention provides a hoist safe conversion braking constant deceleration hydraulic system and a braking method to prevent secondary braking from impacting the hoisting system after the constant deceleration braking function fails, and to ensure Reliability of braking.

In order to solve the above problems, the present invention is a hydraulic system for safe conversion braking and constant deceleration of hoist, which includes oil tank, motor, variable pump, accumulator, electromagnetic reversing valve group, brake valve group and pressure reducing valve group, variable pump The inlet of the valve is connected to the fuel tank through the filter screen, the outlet of the variable pump is connected to the P port of the electromagnetic directional valve G1 through the filter screen, and the T port of the electromagnetic directional valve G1 is connected to the first accumulator through the first check valve. The second one-way valve is connected to the second accumulator and to the B port of the electromagnetic reversing valve G6; the P port of the electromagnetic reversing valve G6 and the P port of the electromagnetic reversing valve G66 are both connected to the brake valve group The oil inlet of the first brake valve is connected, the P port of the electromagnetic directional valve G7 and the P port of the electromagnetic directional valve G77 are connected to the oil inlet of the second brake valve in the brake valve group; the electromagnetic directional valve The A port of G6, the A port of the electromagnetic directional valve G66 and the P port of the electromagnetic directional valve G2, the P port of the electromagnetic directional valve G22, the P port of the electromagnetic directional valve G3, the P port of the electromagnetic directional valve G33, and Connect the P port of the electromagnetic directional valve G4; the A port of the electromagnetic directional valve G2 and the A port of the electromagnetic directional valve G22 are connected in parallel with the first pressure reducing valve; the A port of the electromagnetic directional valve G3, the electromagnetic directional valve The port A of G33 is connected in parallel with the second pressure reducing valve; the third pressure reducing valve is connected in parallel between the P port of the electromagnetic directional valve G4 and the P port of the electromagnetic directional valve G33; The setting value is smaller than the setting value of the second pressure reducing valve, and the setting value of the second pressure reducing valve is smaller than the setting value of the third pressure reducing valve.

Further, the T port of the electromagnetic directional valve G4 is connected to the P port of the electromagnetic directional valve G44, the T port of the electromagnetic directional valve G44 is connected to the B port of the electromagnetic proportional directional valve G5, and the P of the electromagnetic proportional directional valve G5 The port is connected in parallel on the oil path connecting the second accumulator and the second one-way valve, and the T port of the electromagnetic proportional reversing valve G5 is connected to the oil tank through an electromagnetic overflow valve.

Further, the first accumulator is respectively connected to the B port of the electromagnetic reversing valve G2 and the B port of the electromagnetic reversing valve G22 through the first throttle valve, and to the B port of the electromagnetic reversing valve G3 through the second throttle valve. , Connect the B port of the electromagnetic directional valve G33.

Further, the oil inlet of the electromagnetic proportional relief valve is connected in parallel on the oil path connecting the outlet of the variable pump and the P port of the electromagnetic directional valve G1, and the oil outlet of the electromagnetic proportional relief valve is connected to the oil tank through a radiator.

Electromagnetic directional valve G1, electromagnetic directional valve G2, electromagnetic directional valve G22, electromagnetic directional valve G3, electromagnetic directional valve G33, electromagnetic directional valve G4, electromagnetic directional valve G44, electromagnetic directional valve G6, electromagnetic directional valve The direction valve G66, the electromagnetic direction valve G7, and the electromagnetic direction valve G77 are all equipped with valve position monitoring sensors.

The T port of the electromagnetic reversing valve G1, the inlets of the first and second accumulators, the A port of the electromagnetic reversing valve G, and the oil inlet of the brake group are all equipped with oil pressure sensors.

A braking method for a hydraulic system with a constant deceleration and safe conversion braking of a hoist is characterized in that it comprises the following steps:

a) When braking under normal working conditions, the power supply voltage of the proportional relief valve gradually decreases from the working voltage to zero, the oil pressure gradually decreases from the working oil pressure to the residual pressure, and the brake group is gradually closed to reach full system When moving, the hoist stops working;

b) When the hoist has a safety failure, the control motor 2 stops working, the electromagnetic reversing valve G1 is in the right position when the power is lost, and the hoist is safely braked according to different positions of the hoisting container in the well, as follows:

When the lifting container is located at the wellhead, the parallel electromagnetic reversing valve G7 and electromagnetic reversing valve G77 immediately lose power and switch to the right position. The hydraulic oil of the brake group is quickly returned to the tank, and the oil pressure quickly drops to zero. The brake reaches the full braking state, realizing immediate stop;

When the lifting vessel is located in the well, the parallel electromagnetic directional valve G6 and electromagnetic directional valve G66 immediately lose power and switch to the right position, while the parallel electromagnetic directional valve G7 and electromagnetic directional valve G77 do not act and maintain the left position. The electromagnetic reversing valve G2, the electromagnetic reversing valve G22, the electromagnetic reversing valve G3, and the electromagnetic reversing valve G33 do not operate and maintain the left position. The oil pressure of the brake group will immediately drop from the working oil pressure to the third pressure reducing valve setting. Fixed oil pressure;

At the same time, the electromagnetic reversing valve G4 and the electromagnetic reversing valve G44 are in the right position when the power is lost, and the electromagnetic proportional reversing valve G5 is constantly reversing left and right. When the electromagnetic proportional reversing valve G5 is in the right position, the second accumulator is in the right position. When the electromagnetic proportional directional valve G5 is in the left position, the oil in the brake group will flow back to the tank through the electromagnetic overflow valve to increase the deceleration value to make up for the excessive deceleration value. The oil pressure of the group decreases linearly and slowly, and the deceleration of the lifting container is maintained in a stable range until the oil pressure drops to zero and it is in a fully braked state;

c). Realize constant deceleration braking by adjusting the supply voltage of electromagnetic proportional directional valve G5. When the deceleration is too large or too small and the constant deceleration braking fails, immediately switch to secondary braking: electromagnetic directional valve G4 , The electromagnetic directional valve G44 is energized in the left position, blocking the system from performing constant deceleration braking, while the electromagnetic directional valve G2 and the electromagnetic directional valve G22 are de-energized or the electromagnetic directional valve G3 and the electromagnetic directional valve G33 are de-energized. The right position makes the oil pressure drop of the brake group to the set value of the first pressure reducing valve or the second pressure reducing valve, and the first accumulator passes the first throttle valve or the second throttle at the same time The valve replenishes fluid to the brake group to stabilize the system at a secondary brake oil pressure value. The hoist is in a half-brake state. After a delay of 5 seconds, the electromagnetic directional valve G7 and the electromagnetic directional valve G77 are de-energized and are on the right. Position, so that the oil pressure drop of the brake group is zero, and the hoist is fully braked.

Specifically, the secondary braking in step c) above is realized in the following two ways:

The first type, when the oil pressure of the brake group is lower than the setting value of the second pressure reducing valve and higher than the setting value of the first pressure reducing valve, the electromagnetic directional valve G2 and the electromagnetic directional valve G22 fail Electric, implement low oil pressure secondary braking;

The second type, when the oil pressure value of the brake group is higher than the setting value of the second pressure reducing valve, the electromagnetic reversing valve G3 and the electromagnetic reversing valve G33 are de-energized, and high oil pressure secondary braking is performed.

The invention avoids the impact of the accumulator's rapid pressure increase on the lifting system caused by the rapid pressure increase of the accumulator during the braking process through the different reversal of the electromagnetic proportional reversing valve, so that the oil pressure of the brake group is linearly and slowly reduced, and the lifting container is kept stable and decelerated; When deceleration fails, immediately switch to the secondary brake, and use the first and second pressure reducing valves to ensure that the lifting system first reduces the pressure to the set secondary brake oil pressure at a stable speed to increase The machine is in a semi-braking state, and after a delay, the pressure is reduced to zero to achieve full braking. The secondary braking method realized by this hydraulic system is safer and more reliable than previous braking methods, and the speed reduction process is more stable, avoiding the impact of the oil pressure falling too fast or the sudden pressure compensation of the accumulator on the lifting system It can also selectively brake the secondary brake oil pressure after the constant pressure brake function fails.

Description of the drawings

Figure 1 is a schematic diagram of the hydraulic system in the present invention;

In the figure: 1. Oil tank; 2. Motor; 3. Variable pump; 4. Electromagnetic proportional relief valve; 5.1. The first one-way valve; 5.2. The second one-way valve; 6.1. The first accumulator; 6.2. The second accumulator; 7, the electromagnetic overflow valve; 8.1, the first pressure reducing valve; 8.2, the second pressure reducing valve; 8.3, the third pressure reducing valve; 9.1 the first throttle valve; 9.2, the second throttle Valve; 10. Valve position monitoring sensor; 11. Oil pressure sensor; 12. Brake brake group; electromagnetic reversing valve G1, electromagnetic reversing valve G2, electromagnetic reversing valve G22, electromagnetic reversing valve G3, electromagnetic reversing valve G33, electromagnetic directional valve G4, electromagnetic directional valve G44, electromagnetic proportional directional valve G5, electromagnetic directional valve G6, electromagnetic directional valve G66, electromagnetic directional valve G7, electromagnetic directional valve G77.

Detailed ways

The present invention will be described in detail below in conjunction with the drawings and specific embodiments.

As shown in Figure 1, a hydraulic system for safe conversion braking and constant deceleration of a hoist includes an oil tank 1, a motor 2, a variable pump 3, an accumulator, an electromagnetic reversing valve group, a brake valve group and a pressure reducing valve group. The inlet of the variable pump 3 is connected to the fuel tank 1 through the filter screen, the outlet of the variable pump 3 is connected to the P port of the electromagnetic directional valve G1 through the filter, and the outlet of the variable pump 3 is connected to the P port of the electromagnetic directional valve G1 The oil inlet of the electromagnetic proportional relief valve 4 is connected in parallel on the oil circuit, and the oil outlet of the electromagnetic proportional relief valve 4 is connected to the oil tank through the radiator;

The T port of the electromagnetic reversing valve G1 is connected to the first accumulator 6.1 through the first one-way valve 5.1, connected to the second accumulator 6.2 through the second one-way valve 5.2, and connected to the B of the electromagnetic reversing valve G6. The P port of the electromagnetic reversing valve G6 and the P port of the electromagnetic reversing valve G66 are connected to the first brake valve oil inlet of the brake valve group 12. The P port of the electromagnetic reversing valve G7 and the solenoid The P port of the direction valve G77 is connected to the second brake valve oil inlet of the brake valve group 12, the T port of the electromagnetic directional valve G6, the T port of the electromagnetic directional valve G66, and the T port of the electromagnetic directional valve G7 Port and T port of solenoid directional valve G77 return oil to the tank; solenoid directional valve G6 port A, solenoid directional valve G66 port A, solenoid directional valve G2 port P, solenoid directional valve G22 port P Port, the P port of the electromagnetic directional valve G3, the P port of the electromagnetic directional valve G33 and the P port of the electromagnetic directional valve G4 are connected; the A port of the electromagnetic directional valve G2 and the A port of the electromagnetic directional valve G22 are connected in parallel with The first pressure reducing valve 8.1 is connected; the A port of the electromagnetic directional valve G3 and the A port of the electromagnetic directional valve G33 are connected in parallel to the second pressure reducing valve 8.2; the P port of the electromagnetic directional valve G4 is connected to the electromagnetic directional valve G33 The third pressure reducing valve 8.3 is connected in parallel on the oil path connected between the P ports; the setting value of the first pressure reducing valve 8.1 is less than the setting value of the second pressure reducing valve 8.2, and the setting value of the second pressure reducing valve 8.2 is less than The setting value of the third pressure reducing valve 8.3;

The T port of the electromagnetic directional valve G4 is connected to the P port of the electromagnetic directional valve G44, the T port of the electromagnetic directional valve G44 is connected to the B port of the electromagnetic proportional directional valve G5, and the P port of the electromagnetic proportional directional valve G5 is connected in parallel On the oil path where the second accumulator 6.2 is connected to the one-way valve 5.2, the T port of the electromagnetic proportional directional valve G5 is connected to the oil tank through the electromagnetic overflow valve 7.

Adjust the opening of the electromagnetic proportional directional valve G5 by adjusting the voltage of the electromagnetic proportional directional valve G5, so as to realize the adjustment of the braking speed; through the different commutation of the electromagnetic proportional directional valve G5, prevent the pressure from falling too fast or suddenly rising It suppresses the impact on the lifting system and avoids safety accidents.

The first accumulator 6.1 is respectively connected to the B port of the electromagnetic reversing valve G2 and the B port of the electromagnetic reversing valve G22 through the first throttle valve 9.1, and to the B port of the electromagnetic reversing valve G3 through the second throttle valve 9.2. , Connect the B port of the electromagnetic directional valve G33.

The first accumulator 6.1 supplies fluid to the brake valve group 12 through two sets of electromagnetic reversing valves, so that the two-stage hydraulic brake can be selected during the two-stage braking process.

Electromagnetic directional valve G1, electromagnetic directional valve G2, electromagnetic directional valve G22, electromagnetic directional valve G3, electromagnetic directional valve G33, electromagnetic directional valve G4, electromagnetic directional valve G44, electromagnetic directional valve G6, electromagnetic directional valve The direction valve G66, the electromagnetic direction valve G7, and the electromagnetic direction valve G77 are all provided with a valve position monitoring sensor 10.

The T port of the electromagnetic reversing valve G1, the inlets of the first accumulator 6.1 and the second accumulator 6.2, the A port of the electromagnetic reversing valve G6, and the oil inlet of the brake group 12 are all equipped with an oil pressure sensor 11.

Before normal operation, the motor 2 starts, the electromagnetic directional valve G6 is de-energized, and is in the right position, the electromagnetic directional valve G1, the electromagnetic directional valve G2, the electromagnetic directional valve G22, the electromagnetic directional valve G3, the electromagnetic directional valve G33, The electromagnetic directional valve G4, electromagnetic directional valve G44, electromagnetic directional valve G66, electromagnetic directional valve G7, electromagnetic directional valve G77 are all energized and are in the left position, and the electromagnetic proportional directional valve G5 is in the neutral position and does not act; The pressure oil pumped by the pump 3 is adjusted by the proportional relief valve 4 to charge the first accumulator 6.1 and the second accumulator 6.2 through the first check valve 5.1 and the second check valve 5.2 respectively until reaching the oil pressure The size of the sensor 11 is set, the proportional relief valve 4 is opened to the maximum, and the oil filling is completed, the system can enter normal operation.

In normal operation, the electromagnetic directional valve G1, electromagnetic directional valve G2, electromagnetic directional valve G22, electromagnetic directional valve G3, electromagnetic directional valve G33, electromagnetic directional valve G4, electromagnetic directional valve G44, electromagnetic directional valve G6, electromagnetic reversing valve G66, electromagnetic reversing valve G7, electromagnetic reversing valve G77 are all energized, in the left position, electromagnetic proportional reversing valve G5 is in the neutral position and does not operate; the power supply voltage of proportional relief valve 4 is gradually adjusted When the working voltage is reached, the brake group 12 opens slowly, the oil pressure gradually rises to the working oil pressure, and the system enters normal operation.

A method for braking a hydraulic system with a constant deceleration and safe conversion braking of a hoist includes the following steps:

a). When braking under normal working conditions, the power supply voltage of the proportional relief valve 4 gradually decreases from the working voltage to zero, and the oil pressure gradually decreases from the working oil pressure to the residual pressure, and the brake group 12 gradually closes, reaching In full braking state, the hoist stops working;

When the lifting container is located at the wellhead, the parallel electromagnetic reversing valve G7 and electromagnetic reversing valve G77 immediately lose power and switch to the right position. The hydraulic oil of the brake group 12 quickly returns to the oil tank, and the oil pressure quickly drops to zero. Class brake reaches full braking state, realizing immediate stop;

When the lifting vessel is located in the well, the parallel electromagnetic directional valve G6 and electromagnetic directional valve G66 immediately lose power and switch to the right position, while the parallel electromagnetic directional valve G7 and electromagnetic directional valve G77 do not act and maintain the left position. The electromagnetic reversing valve G2, the electromagnetic reversing valve G22, the electromagnetic reversing valve G3, and the electromagnetic reversing valve G33 do not operate and maintain the left position, and the oil pressure of the brake group 12 is immediately reduced from the working oil pressure to the third pressure reducing valve 8.3 Set oil pressure;

At the same time, the electromagnetic reversing valve G4 and the electromagnetic reversing valve G44 are in the right position when the power is lost, and the electromagnetic proportional reversing valve G5 is constantly reversing left and right. When the electromagnetic proportional reversing valve G5 is in the right position, the second accumulator 6.2 The brake group 12 performs fluid replenishment to compensate for the excessive deceleration value. When the electromagnetic proportional directional valve G5 is in the left position, the oil in the brake group 12 returns to the tank through the electromagnetic overflow valve 7, increasing the deceleration value, thereby The oil pressure of the brake group 12 is slowly reduced linearly, and the deceleration of the lifting container is maintained in a stable range until the oil pressure drops to zero, and it is in a fully braked state;

c). Realize constant deceleration braking by adjusting the supply voltage of electromagnetic proportional directional valve G5. When the deceleration is too large or too small and the constant deceleration braking fails, immediately switch to secondary braking: electromagnetic directional valve G4 , The electromagnetic directional valve G44 is energized in the left position, blocking the system from performing constant deceleration braking, while the electromagnetic directional valve G2 and the electromagnetic directional valve G22 are de-energized or the electromagnetic directional valve G3 and the electromagnetic directional valve G33 are de-energized. The right position makes the oil pressure drop of the brake group 12 equal to the setting value of the first pressure reducing valve 8.1 or the setting value of the second pressure reducing valve 8.2, and the first accumulator 6.1 passes the first throttle valve 9.1 Or the second throttle valve 9.2 replenishes fluid to the brake group 12 to stabilize the system at a secondary brake oil pressure value, and the hoist is in a semi-brake state. After a delay of 5 seconds, the solenoid directional valve G7 and solenoid switch The power to valve G77 is in the right position, so that the oil pressure drop of the brake group 12 is zero, and the hoist is fully braked.

The first type, when the oil pressure value of the brake group 12 is lower than the setting value of the second pressure reducing valve 8.2 and higher than the setting value of the first pressure reducing valve 8.1, the electromagnetic reversing valve G2, electromagnetic reversing Valve G22 loses power and performs low oil pressure secondary braking;

In the second type, when the oil pressure value of the brake group 12 is higher than the setting value of the second pressure reducing valve 8.2, the electromagnetic directional valve G3 and the electromagnetic directional valve G33 are de-energized, and high oil pressure secondary braking is performed.

Claims

A hydraulic system for safe conversion braking and constant deceleration of a hoist, comprising an oil tank (1), a motor (2), a variable pump (3), an accumulator, an electromagnetic reversing valve group and a brake valve group, and is characterized by Including the pressure reducing valve group, the inlet of the variable pump (3) is connected to the fuel tank (1) through a filter screen, and the outlet of the variable pump (3) is connected to the P port of the electromagnetic directional valve (G1) through the filter screen. The electromagnetic directional valve The T port of (G1) is connected to the first accumulator (6.1) through the first one-way valve (5.1), connected to the second accumulator (6.2) through the second one-way valve (5.2), and to the electromagnetic The B port of the reversing valve (G6) is connected; the P port of the electromagnetic reversing valve (G6) and the P port of the electromagnetic reversing valve (G66) are both connected to the first brake valve in the brake valve group (12) The solenoid reversing valve (G7) P port and the solenoid reversing valve (G77) P port are connected to the second brake valve oil inlet in the brake valve group (12); the solenoid reversing valve ( G6) port A, solenoid directional valve (G66) A port and solenoid directional valve (G2) P port, solenoid directional valve (G22) P port, solenoid directional valve (G3) P port, The P port of the electromagnetic directional valve (G33) is connected to the P port of the electromagnetic directional valve (G4); the A port of the electromagnetic directional valve (G2) and the A port of the electromagnetic directional valve (G22) are connected in parallel with the first reducing valve. The pressure valve (8.1) is connected; the A port of the solenoid directional valve (G3) and the A port of the solenoid directional valve (G33) are connected in parallel to the second pressure reducing valve (8.2); the P of the solenoid directional valve (G4) The third pressure reducing valve (8.3) is connected in parallel on the oil path connecting the solenoid valve (G33) with the P port; the setting value of the first pressure reducing valve (8.1) is smaller than that of the second pressure reducing valve (8.2) The setting value, the setting value of the second pressure reducing valve (8.2) is less than the setting value of the third pressure reducing valve (8.3).
The safe conversion brake constant deceleration hydraulic system of the hoist according to claim 1, characterized in that the T port of the electromagnetic directional valve (G4) is connected to the P port of the electromagnetic directional valve (G44), and the electromagnetic directional valve ( The T port of G44) is connected to the B port of the electromagnetic proportional directional valve (G5), and the P port of the electromagnetic proportional directional valve (G5) is connected in parallel with the second accumulator (6.2) and the second check valve (5.2) On the oil circuit, the T port of the electromagnetic proportional directional valve (G5) is connected to the oil tank through the electromagnetic overflow valve 7.
The safety conversion brake constant deceleration hydraulic system of the hoist according to claim 2, wherein the accumulator (6.1) passes through the first throttle valve (9.1) and the electromagnetic reversing valve (G2) B port, The solenoid reversing valve (G22) is connected to port B, and the second throttle valve (9.2) is connected to port B of the solenoid reversing valve (G3) and port B of the solenoid reversing valve (G33).
The hydraulic system of claim 3, wherein the safe conversion brake constant deceleration hydraulic system is characterized in that the solenoid proportional relief valve is connected in parallel on the oil path between the outlet of the variable pump 3 and the P port of the solenoid directional valve (G1) The oil inlet of 4 and the oil outlet of the electromagnetic proportional relief valve 4 are connected to the oil tank through a radiator.
The safe conversion brake constant deceleration hydraulic system of the hoist according to any one of claims 1 to 4, characterized in that the electromagnetic directional valve (G1), the electromagnetic directional valve (G2), the electromagnetic directional valve (G22) ), electromagnetic directional valve (G3), electromagnetic directional valve (G33), electromagnetic directional valve (G4), electromagnetic directional valve (G44), electromagnetic directional valve (G6), electromagnetic directional valve (G66), The electromagnetic reversing valve (G7) and the electromagnetic reversing valve (G77) are equipped with valve position monitoring sensors (10).
The hydraulic system for safe conversion braking and constant deceleration of the hoist according to claim 5, characterized in that the T port of the electromagnetic reversing valve (G1), the first accumulator (6.1), the second accumulator (6.2) The inlet of the solenoid valve (G6), the A port of the electromagnetic reversing valve (G6), and the oil inlet of the brake group (12) are equipped with an oil pressure sensor (11).
A braking method for a hydraulic system with a constant deceleration and safe conversion braking of a hoist is characterized in that it comprises the following steps:

a) When braking under normal working conditions, the supply voltage of the proportional relief valve (4) gradually decreases from the working voltage to zero, the oil pressure gradually decreases from the working oil pressure to the residual pressure, and the brake group (12) gradually Close the brake and reach the full braking state, and the hoist stops working;

b) When the hoist has a safety failure, the control motor (2) stops working, the electromagnetic reversing valve (G1) is in the right position when power is lost, and the safe brake of the hoist is realized according to different positions of the hoisting container in the well, as follows :

When the lifting container is located at the wellhead, the parallel electromagnetic reversing valve (G7) and electromagnetic reversing valve (G77) immediately lose power and switch to the right position. The hydraulic oil of the brake group (12) quickly returns to the tank, and the oil pressure is rapid Reduce to zero, reach full braking state through primary braking, and realize immediate stop;

When the lifting vessel is located in the well, the parallel electromagnetic directional valve (G6) and electromagnetic directional valve (G66) immediately lose power and switch to the right position, while the parallel electromagnetic directional valve (G7) and electromagnetic directional valve (G77) ) Do not operate to maintain the left position, the electromagnetic directional valve (G2), electromagnetic directional valve (G22), electromagnetic directional valve (G3), electromagnetic directional valve (G33) do not operate to maintain the left position, and brake the brake group (12) The oil pressure immediately drops from the working oil pressure to the oil pressure set by the third pressure reducing valve (8.3);

At the same time, the electromagnetic reversing valve (G4) and the electromagnetic reversing valve (G44) are in the right position when the power is lost, and the electromagnetic proportional reversing valve (G5) constantly changes left and right. When the electromagnetic proportional reversing valve (G5) is in the right position , The second accumulator (6.2) replenishes the brake group (12) to compensate for the excessive deceleration value. When the electromagnetic proportional directional valve (G5) is in the left position, the oil in the brake group (12) The liquid returns to the fuel tank through the electromagnetic overflow valve (7), increasing the deceleration value, so that the oil pressure of the brake group (12) is linearly and slowly reduced, and the deceleration of the lifting container is maintained in a stable range until the oil pressure drops Is zero, in a fully braked state;

c). Constant deceleration braking is achieved by adjusting the supply voltage of the electromagnetic proportional directional valve (G5). When the deceleration is too large or too small and the constant deceleration braking fails, immediately switch to the secondary braking: electromagnetic commutation The valve (G4) and the electromagnetic directional valve (G44) are energized in the left position, blocking the system from constant deceleration braking, and the electromagnetic directional valve (G2) and electromagnetic directional valve (G22) are de-energized or the electromagnetic directional valve (G3), the electromagnetic reversing valve (G33) is in the right position when the power is lost, so that the oil pressure drop of the brake group (12) is the set value of the first pressure reducing valve (8.1) or the second pressure reducing valve (8.2 ), while the first accumulator (6.1) replenishes the brake group (12) through the first throttle valve (9.1) or the second throttle valve (9.2), so that the system is stabilized at a second stage The brake oil pressure value, the hoist is in the semi-brake state, after a delay of 5 seconds, the electromagnetic reversing valve (G7) and the electromagnetic reversing valve (G77) are in the right position after power failure, so that the brake group (12) The oil pressure drop is zero and the hoist is fully braked.
The braking method of the hoist safe conversion braking constant deceleration hydraulic system according to claim 7, characterized in that the secondary braking in the step c) is realized in the following two ways:

The first type: when the oil pressure of the brake group (12) is lower than the setting value of the second pressure reducing valve (8.2) and higher than the setting value of the first pressure reducing valve (8.1), the electromagnetic reversal The valve (G2) and the electromagnetic reversing valve (G22) lose power and perform low oil pressure secondary braking;

The second type, when the oil pressure value of the brake group (12) is higher than the setting value of the second pressure reducing valve (8.2), the solenoid directional valve (G3) and solenoid directional valve (G33) lose power and execute High oil pressure secondary braking.