CN218817296U - Floating control system of constant delivery pump system - Google Patents

Abstract

The utility model discloses a floating control system of a quantitative pump system, which relates to the technical field of a floating mechanism, and comprises: a quantitative pump, a floating control valve, a floating mechanism, a boom function valve, an executive mechanism and a control device, a quantitative pump, a floating control valve And the floating mechanism is connected in sequence, the quantitative pump, the boom function valve and the actuator are connected in sequence, the floating control valve includes a pressure reducing valve and a floating switching valve, the boom function valve includes a differential relief valve and a proportional reversing valve; The flow valve and the proportional reversing valve are set in parallel between the quantitative pump and the oil return tank, the floating switching valve and the differential relief valve are connected through the feedback oil circuit, and there is a single The actuator is connected to the feedback oil circuit through the proportional directional valve. This system can provide constant pressure for the floating mechanism without affecting the steering action output of the actuator.

Description

A floating control system for quantitative pump system

technical field

The utility model relates to the technical field of floating mechanisms, in particular to a floating control system of a quantitative pump system.

Background technique

In the prior art, in order to improve the off-road performance and operating comfort of the chassis, the aerial work platform generally has a floating function. When walking, the hydraulic system needs to provide a constant pressure for the floating mechanism to ensure that the floating mechanism can respond in time. , it is also necessary to ensure that the output of the steering action is not affected when the floating mechanism is active.

In view of the control requirements of the above aerial work platforms, some aerial work platforms use quantitative pump systems. This system usually uses an electric proportional relief valve to give a signal to the electric proportional relief valve when the system is running to keep it at a relatively low pressure. At the same time, when the floating constant pressure standby is required, the current signal of the electric proportional relief valve is adjusted to adjust the pressure of the electric proportional relief valve to keep it at the pressure value required for floating. In order to ensure that the steering can be performed while walking, the pressure value also needs to take into account the steering pressure. Because the cost of the electric proportional overflow valve itself is relatively high, and it has high requirements for control, it is difficult to match the control.

To sum up, how to provide a constant pressure for the floating mechanism without affecting the output of the steering action is an urgent problem to be solved by those skilled in the art.

Utility model content

In view of this, the purpose of this utility model is to provide a floating control system of a quantitative pump system, which can provide a constant pressure for the floating mechanism without affecting the steering action output of the actuator.

In order to achieve the above object, the utility model provides the following technical solutions:

A floating control system of a quantitative pump system, comprising: a quantitative pump, a floating control valve, a floating mechanism, a boom function valve, an actuator, and a control device, the quantitative pump, the floating control valve, and the floating mechanism are connected in sequence, The quantitative pump, the boom function valve and the actuator are connected in sequence, the floating control valve includes a pressure reducing valve and a floating switching valve, the boom function valve includes a differential overflow valve and is used to control the Proportional directional valve for reversing the actuator;

The differential relief valve and the proportional reversing valve are arranged in parallel between the quantitative pump and the oil return tank, the floating switching valve and the differential relief valve are connected through a feedback oil circuit, and the A one-way valve is provided between the floating switch valve and the differential relief valve, and the actuator is connected to the feedback oil circuit through the proportional directional valve, and is used to drive the motor of the quantitative pump to rotate, The electromagnetic valve used for controlling the action in the floating control valve and the electromagnetic valve used for controlling the action in the boom function valve are both connected to the control device.

Preferably, a pressure sensor for detecting system pressure is provided at the outlet of the quantitative pump, and the pressure sensor is connected to the control device, and the control device is used for switching between the floating control valve and the boom function valve. output, but when it is detected that the outlet pressure of the quantitative pump is higher than the preset range of the standby pressure, it is determined that the system is faulty, so as to control the quantitative pump to stop running.

Preferably, the boom function valve further includes an unloading valve, one end of the unloading valve is set on the feedback oil circuit, and the other end is connected to the oil return tank.

Preferably, the boom function valve further includes a main relief valve, one end of the main relief valve is arranged on the feedback oil circuit, and the other end is connected to the oil return tank.

Preferably, the output end of the quantitative pump is provided with a one-way valve.

Preferably, the number of the actuator and the proportional reversing valve is greater than or equal to one, and the actuator is connected to the proportional reversing valve in a one-to-one correspondence.

Preferably, both the input end and the output end of the actuator are connected to the feedback oil circuit through a one-way valve.

Preferably, the actuator is provided with a detection sensor for monitoring the operation of the actuator, the detection sensor is connected to the control device, and the control device is used to monitor the actuator when the detection sensor detects When there is an action output but no control signal is output to the control valve of the actuator, it is determined that the boom function valve is faulty, so that the control system stops running.

Preferably, the actuator is a steering cylinder.

When using the floating control system of the fixed-difference pump system provided by the utility model, when the fixed-difference pump starts to operate, a certain amount of oil will be output to the system. When it reaches the feedback port of the differential relief valve, the opening pressure of the differential relief valve is the spring setting pressure. At this time, the oil flowing out from the quantitative pump overflows through the differential relief valve, and the overflow pressure is the same as the differential pressure. The spring force of the overflow valve is the same, and the system is in a low pressure standby state.

When the output of the actuator is required, the proportional reversing valve changes direction. At this time, the load pressure is fed back to the feedback port of the differential relief valve. Small, the outlet pressure of the quantitative pump increases, and more oil enters the actuator through the proportional reversing valve. That is, the flow rate of the proportional reversing valve is not changed by the change of the load, and at the same time, the load sensitive control of the quantitative pump system can be realized in this way. After the action is completed, the proportional reversing valve slowly moves to the neutral position, the feedback oil circuit unloads, the oil at the outlet of the quantitative pump passes through the differential relief valve to overflow at low pressure again, and the system returns to the low-pressure standby state.

When the aerial work platform is walking, it is necessary to provide a stable standby pressure for the floating mechanism. At this time, the floating switching valve is switched and connected, and the pressure behind the pressure reducing valve is fed back to the feedback port of the differential relief valve through the floating switching valve. The valve port of the relief valve decreases under the action of the pressure at both ends and the spring force. At this time, since each working valve port is in a closed state, after the oil accumulates, the pressure at the outlet of the quantitative pump rises due to the reduction of the valve port and the decrease of the overflow volume. High, when the pressure rises to the set pressure of the pressure reducing valve, the pressure behind the pressure reducing valve will no longer rise, that is, the feedback pressure of the feedback oil circuit will no longer rise, at this time, the fixed differential relief valve will not rise due to the spring Under the action of force, its valve port will continue to decrease until the pressure at the outlet of the quantitative pump is maintained at the sum of the feedback pressure behind the pressure reducing valve and the spring setting pressure of the differential relief valve, and the valve port of the differential relief valve is no longer changes, the system maintains balance. The part of the overflow oil that is reduced due to the reduction of the valve port of the differential relief valve can be used to maintain the internal leakage of the system. At this time, the outlet pressure of the fixed-difference pump does not change any more, thus realizing the function of providing a stable standby pressure for the floating mechanism. .

The system composes the load-sensing system of the fixed-difference pump through the fixed-difference overflow valve to realize low-pressure standby. At the same time, it provides stable constant-pressure standby pressure for the floating mechanism through the floating control valve and the feedback oil circuit. Moreover, since there is a one-way valve between the floating switching valve and the differential relief valve, the oil only flows from the floating switching valve to the differential relief valve, which effectively avoids backflow in the feedback oil circuit. Therefore, when the floating mechanism works It does not affect the steering output of the actuator when it is active, and the two do not interfere with each other, which can ensure that the system will not affect the normal output of the steering action of the actuator while the system is on standby with floating constant pressure.

To sum up, the floating control system of the quantitative pump system provided by the utility model can provide constant pressure for the floating mechanism without affecting the steering action output of the actuator.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description It is only an embodiment of the utility model, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is a schematic diagram of component connections of the floating control system of the quantitative pump system provided by the present invention.

In Figure 1:

1 is fixed pump, 2 is floating control valve, 21 is pressure reducing valve, 22 is floating switching valve, 3 is floating mechanism, 4 is boom function valve, 41 is differential relief valve, 42 is proportional reversing valve, 43 is an unloading valve, 44 is a main relief valve, 5 is an actuator, 6 is a pressure sensor, 7 is an oil return tank, 8 is a feedback oil circuit, 9 is a check valve, 10 is a detection sensor, and 11 is a control device.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

The core of the utility model is to provide a fixed-quantity pump system floating control system, which can provide constant pressure for the floating mechanism without affecting the steering action output of the actuator.

Please refer to FIG. 1 , which is a schematic diagram of component connection of the floating control system of the quantitative pump system provided by the present invention.

This specific embodiment provides a floating control system for a quantitative pump system, including: a quantitative pump 1, a floating control valve 2, a floating mechanism 3, a boom function valve 4, an actuator 5 and a control device 11, a quantitative pump 1, a floating control valve The valve 2 and the floating mechanism 3 are connected sequentially, the quantitative pump 1, the boom function valve 4 and the actuator 5 are connected sequentially, the floating control valve 2 includes a pressure reducing valve 21 and the floating switching valve 22, and the boom function valve 4 includes a differential overflow The valve 41 and the proportional reversing valve 42 used to control the reversing of the actuator 5; the differential relief valve 41 and the proportional reversing valve 42 are arranged in parallel between the quantitative pump 1 and the oil return tank 7, and the floating switching valve 22 and the differential reversing valve The relief valves 41 are connected through the feedback oil passage 8, and a check valve 9 is provided between the floating switching valve 22 and the differential relief valve 41, and the actuator 5 is connected with the feedback oil passage 8 through the proportional reversing valve 42, The motor for driving the quantitative pump 1 to rotate, the solenoid valve for controlling the action in the floating control valve 2 , and the electromagnetic valve for controlling the action in the boom function valve 4 are all connected to the control device 11 .

It should be noted that the control device 11 of the control device 11 is that the characteristic of the differential relief valve 41 can keep the pressure difference between the front and rear of the proportional reversing valve 42 consistent, which means that when the opening of the proportional reversing valve 42 is completely closed During the opening process, the pressure at the front end of the proportional reversing valve 42 is equal to the pressure at the inlet of the differential relief valve 41, and the pressure at the rear end of the proportional reversing valve 42 is fed back to the spring of the differential relief valve 41 through the check valve 9 On the other hand, since the characteristic of the differential relief valve 41 is that the inlet pressure = the pressure of the feedback port + the spring force, the pressure difference between the front and rear ends of the proportional reversing valve 42 at this time = the inlet pressure - the outlet pressure = the differential relief valve 41 The spring force, so under the action of the differential overflow valve 41, the pressure difference between the inlet and outlet of the proportional reversing valve 42 remains unchanged.

In the actual application process, according to the actual situation and actual needs, the shape, structure, type, position, etc. Make sure.

When using the floating control system of the fixed-difference pump system provided by the utility model, when the fixed-difference pump 1 starts to run, a certain amount of oil will be output to the system. When the load is fed back to the feedback port of the differential relief valve 41, the opening pressure of the differential relief valve 41 is the spring setting pressure. At this time, the oil flowing out from the quantitative pump 1 overflows through the differential relief valve 41, and The overflow pressure is the same as the spring force of the differential overflow valve 41, and the system is in a low pressure standby state.

When the output of the actuator 5 is required, the proportional reversing valve 42 changes direction. At this time, the load pressure is fed back to the feedback port of the differential relief valve 41. The differential relief valve 41 is under the simultaneous action of the pressure on both sides and the spring force. The valve port is reduced, and the outlet pressure of the quantitative pump 1 is increased, so that more oil enters the actuator 5 through the proportional reversing valve 42. At the same time, due to the characteristics of the differential relief valve 41, the proportional reversing valve 42 The pressure difference between the front and back of the pump is always consistent, that is, the flow rate of the proportional reversing valve 42 is not changed by the change of the load, and at the same time, the load sensitive control of the quantitative pump 1 system can be realized in this way. After the action is completed, the proportional reversing valve 42 slowly returns to the neutral position, the feedback oil circuit 8 unloads, and the oil at the outlet of the quantitative pump 1 overflows through the differential overflow valve 41 again at low pressure, and the system returns to the low pressure standby state.

When the aerial work platform is walking, it is necessary to provide a stable standby pressure for the floating mechanism 3. At this time, the floating switching valve 22 is switched and communicated, and the pressure behind the pressure reducing valve 21 is fed back to the pressure of the differential relief valve 41 through the floating switching valve 22. Feedback port, fixed difference relief valve 41, the valve port decreases under the action of the pressure at both ends and the spring force. Small, the outlet pressure of quantitative pump 1 rises. When the pressure rises to the set pressure of pressure reducing valve 21, the pressure behind pressure reducing valve 21 will no longer rise, that is, the feedback pressure of feedback oil circuit 8 will no longer rise. At this time, due to the effect of the spring force on the differential relief valve 41, its valve port will continue to decrease until the pressure at the outlet of the quantitative pump 1 is maintained at the pressure reducing valve 21, and the feedback pressure is the same as the spring of the differential relief valve 41. The sum of the set pressures, the valve port of the differential relief valve 41 no longer changes, and the system maintains balance. The part of the overflow oil that is reduced due to the reduction of the valve port of the fixed differential relief valve 41 can be used to maintain the internal leakage of the system. The role of pressure.

The system composes the load sensitive system of the quantitative pump 1 through the differential overflow valve 41 to realize low-pressure standby, and at the same time, provides stable constant pressure standby pressure for the floating mechanism 3 through the floating control valve 2 and the feedback oil circuit 8 . Moreover, since the check valve 9 is provided between the floating switching valve 22 and the differential relief valve 41, the oil only flows from the floating switching valve 22 to the differential relief valve 41, effectively avoiding backflow in the feedback oil circuit 8, Therefore, when the floating mechanism 3 functions, it does not affect the steering output of the actuator 5, and the two do not interfere with each other, that is, it can be ensured that the system will not affect the normal output of the steering action of the actuator 5 while the floating constant pressure is on standby.

To sum up, the floating control system of the quantitative pump system provided by the present invention can provide constant pressure for the floating mechanism 3 without affecting the steering action output of the actuator 5 .

On the basis of the above-mentioned embodiments, preferably, a pressure sensor 6 for detecting the system pressure is provided at the outlet of the quantitative pump 1, and the pressure sensor 6 is connected to the control device 11, and the control device 11 is used to control the floating control valve 2 and the boom function. When the valve 4 has no output but detects that the outlet pressure of the quantitative pump 1 is higher than the preset range of the standby pressure, the system is judged to be faulty, so as to control the quantitative pump 1 to stop running.

It should be noted that the hydraulic oil is divided into two paths after coming out of the quantitative pump 1, one path to the floating control valve 2, and the other path to the boom function valve 4, so the pressure sensor 6 can not only detect the pressure in front of the pressure reducing valve 21, but also The pressure at the inlet of the boom function valve 4 can be detected. Therefore, when the solenoid valve on the floating control valve 2 and the boom function valve 4 has no output, if the pressure sensor 6 detects that the outlet pressure of the quantitative pump 1 is higher than the preset range of the standby pressure, the control device 11 will determine that the system is faulty, Furthermore, the motor used to drive the fixed displacement pump 1 is controlled to stop rotating, so as to ensure that the hydraulic system is stopped in time when a failure occurs, and the components are effectively protected.

In addition, it should be noted that, as one of the quantitative pumps 1, the gear pump has become the main choice of power source for the hydraulic system of the aerial work platform due to its advantages of simple structure and strong pollution resistance. The fixed-difference pump 1 system mainly adopts the gear pump, and the load-sensing system of the fixed-difference pump 1 is formed through the differential overflow valve 41 to realize low-pressure standby, and at the same time, provide stable constant-pressure standby pressure for the floating mechanism 3 through the floating control circuit, and, While the floating constant voltage is on standby, it does not affect the normal output of the steering action.

It should also be noted that the gear pump is used as the power source of the hydraulic system. When the motor starts to rotate and the gear pump is used as the power source of the hydraulic system, when the motor starts to rotate, a certain amount of oil will be output to the system. Relief valve 41, when there is no load feedback to the feedback port of differential relief valve 41, the opening pressure of differential relief valve 41 is the spring setting pressure, generally 15-20bar, at this time the oil at the outlet end of the gear pump Relief will be performed through the differential relief valve 41, and the pressure is the same as the spring force of the differential relief valve 41, and the system is in a low pressure standby state.

Preferably, the boom function valve 4 further includes an unloading valve 43 , one end of the unloading valve 43 is set on the feedback oil circuit 8 , and the other end is connected to the oil return tank 7 .

It should be noted that when the output of the actuator 5 is required, the unloading valve 43 can be switched to the right position, and the proportional reversing valve 42 will be switched to the right position. At this time, the load pressure will be fed back to the differential relief valve 41 Under the simultaneous action of the pressure on both sides and the spring force, the valve port of the differential relief valve 41 will be closed, so that more oil enters the actuator 5 through the proportional reversing valve 42 . At the same time, due to the characteristics of the differential relief valve 41, the pressure difference between the front and rear of the proportional directional valve 42 is always consistent, that is, the oil flow through the proportional directional valve 42 is not changed by the change of the load, and at the same time, In this way, the load sensitive control of the quantitative pump 1 system is realized. After the action of the actuator 5 is completed, the proportional reversing valve 42 slowly returns to the neutral position, and then the unloading valve 43 switches to the left position, the feedback oil circuit 8 is unloaded, and the oil at the outlet of the quantitative pump 1 passes through the differential overflow again. Flow valve 41 performs low-pressure relief, and the system returns to the low-pressure standby state.

When the aerial work platform is walking, it is necessary to provide a stable standby pressure for the floating mechanism 3. At this time, the unloading valve 43 is switched to the right position, the floating switching valve 22 is switched and is in a connected state, and the pressure behind the pressure reducing valve 21 passes through The floating switching valve 22 and the one-way valve 9 then feed back to the feedback port of the differential relief valve 41, and the valve port of the differential relief valve 41 will decrease under the action of the pressure at both ends and the spring force. At this time, since all the working valve ports are closed, the oil is accumulated, and then the outlet pressure of the quantitative pump 1 rises. When the pressure rises to the set pressure of the pressure reducing valve 21, the pressure behind the pressure reducing valve 21 It no longer increases, which means that the feedback pressure will no longer increase. At this time, due to the action of the spring force of the differential relief valve 41, its valve port will continue to decrease until the outlet pressure of the quantitative pump 1 is maintained at the pressure reducing valve. After 21, the sum of the feedback pressure and the spring setting pressure of the differential relief valve 41, the valve port of the differential relief valve 41 no longer changes, and the system maintains balance. In addition, due to the reduction of the valve port of the differential relief valve 41, the part of the overflow oil can be used to balance the oil leakage inside the system. At this time, the outlet pressure of the quantitative pump 1 will no longer change, so as to achieve The floating mechanism 3 provides the effect of stabilizing the standby pressure.

On the basis of the above embodiments, preferably, the boom function valve 4 further includes a main relief valve 44 , one end of the main relief valve 44 is set on the feedback oil circuit 8 , and the other end is connected to the oil return tank 7 .

Preferably, the output end of the quantitative pump 1 is provided with a one-way valve 9 to effectively limit the oil flow direction and prevent the oil from flowing back to the quantitative pump 1 .

Preferably, the numbers of the actuator 5 and the proportional reversing valve 42 are greater than or equal to one, and the actuator 5 and the proportional reversing valve 42 are connected in one-to-one correspondence.

Preferably, both the input end (port A) and the output end (port B) of the actuator 5 are connected to the feedback oil circuit 8 through the one-way valve 9 .

It should be noted that the oil flows out from the outlet of the quantitative pump 1 , passes through a one-way valve 9 , and reaches the floating control valve 2 and the boom function valve 4 . The oil enters the floating mechanism 3 through the pressure reducing valve 21, and the floating control oil circuit behind the pressure reducing valve 21 is fed back to the boom function valve 4 through the floating switching valve 22 and the one-way valve 9. The internal main oil circuit of the boom function valve 4 is connected with a differential relief valve 41 and two proportional reversing valves 42 (three-position, four-way reversing valves). When the proportional reversing valve 42 changes direction, oil will enter the input or output end, and then flow into the actuator 5. In addition, the feedback oil circuit 8 of the boom function valve 4 is connected to the feedback port of the differential relief valve 41 , connected to the inlet of the unloading valve 43 , the input and output ends of the actuator 5 are connected to the feedback oil circuit 8 through the one-way valve 9 .

When the floating switching valve 22 is switched, the pressure behind the pressure reducing valve 21 will be fed back to the feedback oil circuit 8 through the check valve 9, and then reach the feedback port of the differential relief valve 41 to reduce the pressure of the differential relief valve 41. The valve port increases the outlet pressure of the quantitative pump 1. If there is a steering action at this time, the steering pressure is smaller than the pressure fed back from the floating switching valve 22, and the steering load pressure cannot open the one-way valve at the actuator 5. 9. Feedback to the feedback oil circuit 8. Only when the steering pressure is greater than the feedback pressure behind the floating switching valve 22, the steering pressure will open the check valve 9 at the actuator 5 and reach the feedback oil circuit 8. At this time Since the load pressure of the steering in the feedback oil circuit 8 is greater than the pressure at the floating switching valve 22, the check valve 9 at the floating switching valve 22 will be closed again. Only the maximum load can exist in the feedback oil circuit 8 , and only the maximum load can be fed back to the feedback oil circuit 8 to adjust the opening degree of the differential relief valve 41 .

On the basis of the above-mentioned embodiments, preferably, the actuator 5 is provided with a detection sensor 10 for monitoring the operation of the actuator 5, the detection sensor 10 is connected to the control device 11, and the control device 11 is used to monitor the execution by the detection sensor 10. When the mechanism 5 has an action output but does not output a control signal to the control valve of the actuator 5, it is determined that the boom function valve 4 is faulty, and the control system stops running. At this time, the unloading valve 43 on the boom function valve 4 can be controlled to be energized, and the feedback oil circuit 8 can be cut off to stop the action of the actuator 5; the motor used to drive the quantitative pump 1 can also be controlled to stop running to stop The flow output of the quantitative pump 1 stops the action of the quantitative pump 1.

It should be noted that this system combines some electrical components, and the detection sensor 10 can monitor the control valve faults of each actuator 5 in real time, realize fault detection and alarm, and stop the action of the actuator 5 in time after a fault occurs, so as to provide high-altitude protection for the entire high altitude. The operating platform provides security.

It should be added that when the system is only in the floating output state, assuming that other actuators 5 do not need any output, the system pressure detected by the pressure sensor 6 should be the spring setting value of the differential relief valve 41 and the decompression value. The sum of the set values of the valve 21, but if the pressure value detected by the pressure sensor 6 is greater than this value at this time, it can be judged as a system failure. At this time, a signal to stop the output current can be sent to the unloading valve 43 through the control device 11 , so that the feedback oil circuit 8 is unloaded, and the pressure difference cannot be established at the outlet of the quantitative pump 1. The system determines that the valve group is faulty and sends an alarm signal, which plays the role of safety detection and fault cut-off.

Preferably, the actuator 5 is a steering cylinder.

It should be noted that the actuator 5 is a steering oil cylinder, and it needs to perform a steering operation while walking. The proportional reversing valve 42 used to control the reversing of the actuator 5 also needs reversing accordingly. The oil at the outlet is supplied to the actuator 5. As the oil increases, the load pressure at the actuator 5 gradually increases. When the load pressure of the actuator 5 is greater than the set pressure of the pressure reducing valve 21, the actuator 5 The load pressure begins to play a major role, and the valve port of the differential relief valve 41 is further reduced under the action of the spring force, so that the pressure in front of the proportional reversing valve 42 is increased, and it is always maintained at a range greater than the set value of the spring force . Since the feedback oil circuit 8 behind the pressure reducing valve 21 is provided with a check valve 9, the system will not affect the output of the actuator 5 while the system is on standby at constant pressure.

This system selects the gear pump as the oil source of the system, and realizes floating constant pressure standby by feeding back the pressure after the decompression valve 21 to the differential relief valve 41. Compared with other methods, it is simpler, easier to realize, and more energy-saving, and can reduce System noise and system heat generation. Since the feedback oil circuit 8 of the decompression valve 21 has a check valve 9, it will not affect other actions and enter the load sensitivity while the constant pressure is on standby, which is relatively more energy-saving. Through the cooperation of electrical components and electrical systems, coupled with the unloading valve 43 of the feedback oil circuit 8, it can effectively prevent the safety of the aerial work platform from being affected by the failure of the valve group, and the safety of the system is relatively higher. .

The load sensitive circuit of the quantitative pump 1 system is constituted by the differential relief valve 41, and the floating constant pressure standby is realized through the feedback oil circuit 8 through the pressure reducing valve 21, and there is no connection with other actuators 5 while the floating constant pressure is standby. Mutual influence; using electrical components and unloading valve 43 to cooperate with the electrical system, it is possible to monitor and judge the faults of the control valves of each actuator 5 at floating constant pressure, and to switch in time when a fault occurs, improving the safety of the system reliability.

In addition, it should also be noted that the orientation or positional relationship indicated by "entering and exiting" in this application is based on the orientation or positional relationship shown in the drawings, and is only for simplifying description and understanding, rather than indicating or implying Means that a device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the invention.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other. Any combination of all the embodiments provided by the utility model is within the protection scope of the utility model, and will not be repeated here.

The floating control system of the quantitative pump system provided by the utility model has been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present utility model, and the descriptions of the above embodiments are only used to help understand the method and core idea of the present utility model. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made to the utility model, and these improvements and modifications also fall into the protection of the claims of the utility model. within range.

Claims (9)

1. A constant displacement pump system float control system, comprising: the control system comprises a fixed displacement pump (1), a floating control valve (2), a floating mechanism (3), a movable arm functional valve (4), an actuating mechanism (5) and a control device (11), wherein the fixed displacement pump (1), the floating control valve (2) and the floating mechanism (3) are sequentially connected, the fixed displacement pump (1), the movable arm functional valve (4) and the actuating mechanism (5) are sequentially connected, the floating control valve (2) comprises a pressure reducing valve (21) and a floating switching valve (22), and the movable arm functional valve (4) comprises a fixed differential overflow valve (41) and a proportional reversing valve (42) for controlling the reversing of the actuating mechanism (5);

the constant-difference overflow valve (41) and the proportional reversing valve (42) are arranged in parallel between the fixed displacement pump (1) and the oil return tank (7), the floating switching valve (22) is connected with the constant-difference overflow valve (41) through a feedback oil path (8), the floating switching valve (22) is arranged with a one-way valve (9) between the constant-difference overflow valve (41), and the executing mechanism (5) is used for driving the motor rotating by the fixed displacement pump (1), the electromagnetic valve used for controlling the action in the floating control valve (2) and the electromagnetic valve used for controlling the action in the movable arm functional valve (4) are connected with the control device (11).

2. Fixed displacement pump system floating control system according to claim 1, characterized in that a pressure sensor (6) for detecting system pressure is provided at the outlet of the fixed displacement pump (1), the pressure sensor (6) is connected with the control device (11), and the control device (11) is used for determining system fault to control the fixed displacement pump (1) to stop running when the floating control valve (2) and the boom function valve (4) have no output but detect that the outlet pressure of the fixed displacement pump (1) is higher than a preset standby pressure range.

3. Fixed displacement pump system floating control system according to claim 1, wherein the boom function valve (4) further comprises an unloading valve (43), one end of the unloading valve (43) is arranged on the feedback oil path (8), and the other end is connected with the oil return tank (7).

4. Fixed displacement pump system floating control system according to claim 3, characterized in that the boom function valve (4) further comprises a main overflow valve (44), one end of the main overflow valve (44) is arranged on the feedback oil path (8), and the other end is connected with the oil return tank (7).

5. Dosing pump system floating control system according to one of claims 1 to 4, characterized in that the output of the dosing pump (1) is provided with a non-return valve (9).

6. Dosing pump system floating control system according to any of claims 1 to 4, characterized in that the number of actuators (5) and proportional reversing valves (42) is greater than or equal to one, and the actuators (5) are connected in one-to-one correspondence with the proportional reversing valves (42).

7. Dosing pump system floating control system according to claim 6, characterized in that the actuator (5) is connected to the feedback oil circuit (8) by a one-way valve (9) at both its input and output.

8. Fixed displacement pump system floating control system according to any of claims 1 to 4, characterized in that the actuator (5) is provided with a detection sensor (10) for monitoring the operation condition of the actuator (5), the detection sensor (10) is connected with the control device (11), and the control device (11) is used for determining the fault of the boom functional valve (4) to control the system to stop operating when the detection sensor (10) monitors that the actuator (5) has an action output but does not output a control signal to the control valve.

9. Dosing pump system floating control system according to one of claims 1 to 4, characterized in that the actuator (5) is a steering cylinder.

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