Topological structure of pilot oil way of hydraulic system, heating method and engineering machinery
Through the topological structure and heating method of the pilot oil circuit of the hydraulic system, the hot oil of the hydraulic oil tank is used to preheat the pilot oil circuit, which solves the problem of slow response of the electric proportional pressure reducing valve in low-temperature environments, improves the handling of construction machinery and reduces the controllability of construction machinery cost.
Patent Information
- Application Number
- CN202411437397.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-15
- Publication Date
- 2025-01-07
AI Technical Summary
In low temperature environments, the response time of the electrical proportional pressure reducing valve becomes longer, resulting in poor handling of construction machinery. The existing heating methods cannot effectively solve the temperature problem of the pilot oil circuit, which increases cost and complexity.
Adopt a topological structure of the pilot oil circuit of the hydraulic system, including a hydraulic pump, solenoid valve, temperature sensor and relief valve, and perform heating procedures based on the oil temperature detection results through control logic, and use the hot oil of the hydraulic oil tank to preheat the pilot oil circuit. , simplify the structure and reduce costs.
It realizes efficient preheating of the pilot oil circuit, improves response speed, simplifies structural layout, reduces production costs, and improves equipment handling.
Smart Images
Figure CN119267378A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of engineering machinery, and in particular relates to a topological structure of a pilot oil circuit of a hydraulic system, a heating method and engineering machinery. Background Art
[0002] At present, the application scenarios of construction machinery are becoming more and more diverse. The demand for application in areas with low ambient temperatures such as high latitudes and high altitudes is increasing. At the same time, construction machinery is developing towards electronic control and intelligence. Therefore, the hydraulic system uses a large number of electric proportional pressure reducing valves as pilot stages to convert electrical signals into pressure output signals to control the movement of key core components such as the hydraulic main valve spool, brake, and balance valve spool, thereby controlling the speed and pressure of the actuator. The performance of the electric proportional pressure reducing valve is greatly affected by the hydraulic oil temperature, especially in low temperature environments. The response time of the electric proportional pressure reducing valve (that is, when the electric proportional pressure reducing valve is given a certain control current, the time it takes to build up the output pressure) becomes significantly longer, and the phenomenon of action lag occurs, which seriously affects the controllability of the equipment. Therefore, when the ambient temperature is low, it is urgent to solve the problem of pilot oil circuit heating and increase the temperature of the pilot oil.
[0003] The pilot oil circuit usually provides pressurized oil for different actuators. Since different actuators are distributed in different positions of mechanical equipment, the connection method between the pilot oil circuit's pump, safety valve, voltage stabilizing component, etc. and the electric proportional pressure reducing valve, that is, the topological structure of the pilot oil circuit, will have a great impact on the pilot oil circuit heating.
[0004] The existing technology can solve the heating problem of the hydraulic oil tank through electric heating or overflow heating, but the hydraulic oil in the pilot line cannot be effectively heated. The main reason is that the influence of the pilot oil circuit on the performance of the electric proportional valve has not been studied. Therefore, the problem of slow equipment response cannot be fundamentally solved.
[0005] Some existing solutions use throttling heating to heat the pilot oil circuit, and add a special pilot preheating valve group to each pilot oil circuit. However, before starting any main action such as the pilot pressure reducing valve of the foot valve, left and right pilot handle valves, the cavity from the preheating valve group to the pilot pressure reducing valve is closed. Only after the pilot pressure reducing valve works, the pilot oil flows, and the throttling heating function of the preheating valve group can take effect. Only after the foot valve or the pilot handle has been actuated multiple times, the preheating valve group can take effect. At the same time, this solution also increases the difficulty of arranging the pilot oil circuit, and increases the weight and cost. After the pilot oil circuit and the main hydraulic oil circuit are heated, the heat of the hydraulic system itself will keep the hydraulic oil at a relatively high thermal equilibrium temperature, and even a heat dissipation system is required to maintain the hydraulic oil temperature from being too high. At this time, the pilot preheating valve group is no longer needed. Therefore, the existing solution has an obviously insufficient utilization rate after a large investment, and the cost performance is poor. In addition, some solutions use fixed throttle hole heating. Each pilot oil circuit is equipped with at least one or more fixed throttle holes. While throttling and heating, it will affect the pilot oil pressure and flow output entering the foot valve, pilot handle, etc., and even affect the response time of the pilot circuit. This is not conducive to improving the system response by increasing the pilot oil temperature. Summary of the invention
[0006] In order to solve the deficiencies in the prior art, the present invention provides a topological structure, a heating method and engineering machinery for a pilot oil circuit of a hydraulic system, which can efficiently preheat the pilot oil circuit, improve the response speed of the pilot oil circuit, and at the same time, simplify the structure of the pilot oil circuit, reduce the layout difficulty and production cost.
[0007] In order to achieve the above object, the technical solution adopted by the present invention is:
[0008] In a first aspect, a topological structure of a pilot oil circuit of a hydraulic system is provided, comprising: a hydraulic pump, wherein the inlet of the hydraulic pump is connected to a hydraulic oil tank, the outlet of the hydraulic pump is connected to the inlet of a pressure reducing valve, and the outlet of the pressure reducing valve is connected in parallel to a plurality of pilot control modules; each group of the pilot control modules comprises: a solenoid valve and a plurality of pilot control units connected in series between the outlet of the pressure reducing valve and the inlet of the solenoid valve; each group of the pilot control units comprises: an electric proportional pressure reducing valve and a control chamber arranged on a valve seat; in each group of pilot control units, the outlet of the electric proportional pressure reducing valve is connected to the inlet of the control chamber, and the outlet of the control chamber is connected to the inlet of the electric proportional pressure reducing valve in the next group of pilot control units; wherein the inlet of the electric proportional pressure reducing valve in the first group of pilot control units is connected to the outlet of the pressure reducing valve, and the outlet of the control chamber in the last group of pilot control units is connected to the inlet of the solenoid valve; wherein the electric proportional pressure reducing valve works when energized, its input is an electrical signal, its output is a pressure signal, the output hydraulic oil enters the control chamber, and drives the actuator in the control chamber to move.
[0009] Furthermore, it also includes a second temperature sensor for collecting the outlet oil temperature of the last group of pilot control units and a first temperature sensor for collecting the oil temperature in the hydraulic oil tank.
[0010] Furthermore, when the solenoid valve is not energized, the pilot oil is cut off at the solenoid valve, and when energized, the pilot oil circuit is connected to the hydraulic oil tank, and the pilot oil directly returns to the hydraulic oil tank.
[0011] Furthermore, it also includes a relief valve, the inlet of the relief valve is connected to the outlet of the hydraulic pump, and the outlet of the relief valve is connected to the hydraulic oil tank.
[0012] Furthermore, it also includes an accumulator arranged between the outlet of the hydraulic pump and the inlet of the pressure reducing valve.
[0013] Furthermore, the power source for driving the hydraulic pump to operate includes an engine, a power take-off connected to the engine, or an electric motor.
[0014] Furthermore, the electric proportional pressure reducing valve and its valve seat are connected by a pipeline, the electric proportional pressure reducing valve is integrated on the valve seat, and the oil inlet of the valve seat and the oil inlet of the electric proportional pressure reducing valve are connected by an optimized oil channel with a volume cavity smaller than a set threshold, so as to avoid hydraulic oil retention and improve the preheating effect.
[0015] In a second aspect, a method for heating a pilot oil circuit is provided, wherein the pilot oil circuit adopts the topological structure of the pilot oil circuit of the hydraulic system described in the first aspect, and the heating method comprises: collecting the oil temperature detected by the first temperature sensor and the second temperature sensor; comparing the collected oil temperature with the set oil temperature threshold, and executing corresponding control logic according to the comparison result to complete the heating of the pilot oil circuit.
[0016] Furthermore, the collected oil temperature is compared with the set oil temperature threshold, and the corresponding control logic is executed according to the comparison result, including: when T1≥t1, the controller determines that the current pilot oil temperature meets the conditions for starting the pilot oil circuit, and the controller issues a prompt message "allow the pilot valve to start"; wherein T1 represents the outlet oil temperature of the last group of pilot control units collected by the second temperature sensor, and t1 represents the temperature threshold for allowing the pilot valve to start; when T1<t1, and T0≥t0>t1, the controller issues a prompt message "the pilot oil temperature is low, and the pilot heating program is allowed to start", and the controller sends a control signal to the solenoid valve, the solenoid valve is energized, and the pilot oil flows through each pilot control The electric proportional pressure reducing valve and its valve seat in the control unit return to the hydraulic oil tank to heat the pilot oil circuit, and the oil temperature of the pilot oil circuit rises. When T1≥t1, the controller determines that the current pilot oil temperature meets the conditions for starting the pilot oil circuit, and the controller sends a control signal to the solenoid valve, the solenoid valve loses power, the pilot oil circuit is cut off, and the controller sends a prompt message "The pilot oil has been heated, and the pilot valve is allowed to start"; wherein, T0 represents the oil temperature in the hydraulic oil tank collected by the first temperature sensor, and t0 represents the set preheating temperature of the hydraulic oil in the hydraulic oil tank; when T1<t1, and T0<t0, t0>t1, the controller sends a prompt message "The oil tank temperature is low, please heat the hydraulic oil tank first".
[0017] According to a third aspect, there is provided an engineering machine, wherein the engineering machine is provided with the topological structure of the pilot oil circuit of the hydraulic system according to the first aspect.
[0018] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the inlet of the hydraulic pump is connected to the hydraulic oil tank, the outlet is connected to the inlet of the pressure reducing valve, and the outlet of the pressure reducing valve is connected in parallel to several groups of pilot control modules; each group of pilot control modules includes a solenoid valve and multiple groups of pilot control units connected in series between the outlet of the pressure reducing valve and the inlet of the solenoid valve; each group of pilot control units includes: an electric proportional pressure reducing valve and a control chamber arranged on a valve seat; in each group of pilot control units, the outlet of the electric proportional pressure reducing valve is connected to the inlet of the control chamber, and the outlet of the control chamber is connected to the inlet of the electric proportional pressure reducing valve in the next group of pilot control units; wherein, the inlet of the electric proportional pressure reducing valve in the first group of pilot control units is connected to the outlet of the pressure reducing valve, and the outlet of the control chamber in the last group of pilot control units is connected to the inlet of the solenoid valve; the electric proportional pressure reducing valve works when energized, its input is an electric signal, and its output is a pressure signal, and the output hydraulic oil enters the control chamber to drive the actuator in the control chamber to move; efficient preheating of the pilot oil circuit is achieved, and the response speed of the pilot oil circuit is improved, and at the same time, the structure of the pilot oil circuit is simplified, and the layout difficulty and production cost are reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic diagram of the topological structure principle of a pilot oil circuit of a hydraulic system provided by an embodiment of the present invention;
[0020] Figure 2 yes Figure 1 Schematic diagram of the heating principle of the pilot oil circuit;
[0021] Figure 3 yes Figure 1 A schematic diagram of the principle of an extended oil circuit of the topological structure of the pilot oil circuit of the hydraulic system;
[0022] In the figure: 1. power source; 2. hydraulic pump; 3. overflow valve; 4. hydraulic oil tank; 5. first temperature sensor; 6. accumulator; 7. pressure reducing valve; 8. second temperature sensor; 9. solenoid valve. DETAILED DESCRIPTION
[0023] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.
[0024] Embodiment 1
[0025] like Figure 1 , Figure 3 As shown, a topological structure of a pilot oil circuit of a hydraulic system includes: a power source 1, a hydraulic pump 2, a relief valve 3, a hydraulic oil tank 4, a first temperature sensor 5, an accumulator 6, a pressure reducing valve 7, a second temperature sensor 8, a solenoid valve 9, a three-way connector, an electric proportional pressure reducing valve and a control chamber.
[0026] The inlet of the hydraulic pump 2 is connected to the hydraulic oil tank 4, the outlet of the hydraulic pump 2 is connected to the inlet of the pressure reducing valve 7, and the outlet of the pressure reducing valve 7 is connected in parallel to several groups of pilot control modules.
[0027] Each group of pilot control modules includes: a solenoid valve 9 and a plurality of groups of pilot control units connected in series between the outlet of the pressure reducing valve 7 and the inlet of the solenoid valve 9 .
[0028] Each group of pilot control units includes: an electric proportional pressure reducing valve and a control chamber arranged on a valve seat; in each group of pilot control units, the outlet of the electric proportional pressure reducing valve is connected to the inlet of the control chamber, and the outlet of the control chamber is connected to the inlet of the electric proportional pressure reducing valve in the next group of pilot control units; wherein, the inlet of the electric proportional pressure reducing valve in the first group of pilot control units is connected to the outlet of the pressure reducing valve 7, and the outlet of the control chamber in the last group of pilot control units is connected to the inlet of the solenoid valve 9.
[0029] The power source 1 is mechanically connected to the hydraulic pump 2. Generally, the power source 1 can be an engine, a power take-off connected to the engine, or an electric motor. The hydraulic pump 2 can be a gear pump. The power source 1 drives the hydraulic pump 2 to suck oil from the hydraulic oil tank 4 and pump the hydraulic oil to the pilot oil circuit to provide hydraulic oil for the pilot oil circuit. The relief valve 3 is set at the outlet of the hydraulic pump 2. When the system pressure exceeds its set value, it opens, and the hydraulic oil in the pilot oil circuit is unloaded back to the hydraulic oil tank 4 through the relief valve 3, which plays a role in system protection. The accumulator 6 is set at the outlet of the hydraulic pump 2. When the pilot system pressure exceeds its pre-charge pressure, the accumulator 6 is filled with oil. When the pilot system pressure is lower than its pre-charge pressure, the accumulator 6 discharges oil. The accumulator 6 plays a role in stabilizing the system pressure.
[0030] The present invention is described in detail by setting a group of pilot control modules, and the pilot control module is provided with three groups of pilot control units. Figure 1As shown, the first pilot control unit includes valve seat B1, electric proportional pressure reducing valve PV1 and control chamber MV1 integrated in valve seat B1; the second pilot control unit includes valve seat B2, electric proportional pressure reducing valve PV2 and control chamber MV2 integrated in valve seat B2; the third pilot control unit includes valve seat B3, electric proportional pressure reducing valve PV3 and control chamber MV3 integrated in valve seat B3. The front end (inlet) of pressure reducing valve 7 is connected to hydraulic pump 2, and the rear end (outlet) is connected to electric proportional pressure reducing valve PV1. The function of pressure reducing valve 7 is to make the pressure after the pressure reducing valve not exceed its set value, so as to prevent the harm to the rear end system caused by excessive front end input pressure. The front end of electric proportional pressure reducing valve PV1 is connected to pressure reducing valve 7, and the rear end is connected to control chamber MV1, and the rear end is connected in series with electric proportional pressure reducing valve PV2. When electric proportional pressure reducing valve PV1 is powered on, its input is an electrical signal, and its output is a pressure signal. The output pressure oil enters control chamber MV1 to drive the actuator in control chamber MV1 to move. The control chamber MV1 is connected to the electric proportional pressure reducing valve PV1, and its pressure is determined by the control current of the electric proportional pressure reducing valve PV1. The pressure acts on the action surface in the control chamber MV1 to generate a force, driving the associated actuator to move. In particular, the electric proportional pressure reducing valve PV1 is integrated on the valve seat B1, and an oil unloading oil circuit is also set inside the valve seat B1. When the electric proportional pressure reducing valve PV1 is not working, the hydraulic oil in the control chamber MV1 returns to the hydraulic oil tank 4 through the oil unloading oil circuit. The front end of the electric proportional pressure reducing valve PV2 is connected to the electric proportional pressure reducing valve PV1, and the rear end is connected to the control chamber MV2. At the same time, the rear end is connected in series with the electric proportional pressure reducing valve PV3, and its working principle is the same as that of the electric proportional pressure reducing valve PV1. The working principle of the control chamber MV2 is the same as that of the control chamber MV1. The front end of the electric proportional pressure reducing valve PV3 is connected to the electric proportional pressure reducing valve PV2, and the rear end is connected to the second temperature sensor 8 and the solenoid valve 9 through a three-way connection. The second temperature sensor 8 is used to detect the oil temperature of the last electric proportional pressure reducing valve in the pilot oil circuit and the rear end of its valve seat. When the solenoid valve 9 is not energized, the pilot oil is cut off at the solenoid valve 9. When energized, the pilot oil circuit is connected to the hydraulic oil tank 4, and the pilot oil directly returns to the hydraulic oil tank 4. The hydraulic oil tank 4 has a built-in first temperature sensor 5 for monitoring the temperature of the hydraulic oil in the hydraulic oil tank 4.
[0031] The topological structure of the pilot oil circuit described in the present invention is characterized in that the electric proportional pressure reducing valve and its valve seat are arranged after the pressure reducing valve, and all the electric proportional pressure reducing valves and their valve seats and solenoid valves are serially connected in the pilot oil circuit in a sequential order, wherein the second temperature sensor 8 is arranged between the last group of pilot control units and the solenoid valve 9, and the solenoid valve 9 is arranged between the last group of pilot control units and the hydraulic oil tank 4. The electric proportional pressure reducing valve and its valve seat are connected by a pipeline, the electric proportional pressure reducing valve is integrated on the valve seat, and the oil passage between the oil inlet of the valve seat B1 and the oil inlet PV1 of the electric proportional pressure reducing valve is optimized and designed, and the cavity is small to avoid a large amount of hydraulic oil remaining inside, especially when the electric proportional pressure reducing valve is not working, the pilot oil cannot flow there, and this part of the cavity is equivalent to a "sealed cavity", and it is difficult for this part of the hydraulic oil to achieve heat exchange with the outside, and a small cavity is beneficial to preheating the pilot system.
[0032] Before the pilot oil circuit is heated, the hydraulic system hydraulic oil tank 4 must be preheated, that is, the temperature in the hydraulic oil tank 4 should reach the set preheating temperature t0 of the hydraulic oil in the hydraulic oil tank 4, and the pilot oil circuit is preheated using the hot oil in the hydraulic oil tank 4. Preheating the hydraulic oil tank 4 is a step or operation that must be completed when the equipment is started in a low temperature environment, so this prerequisite does not cause additional work or increase additional costs for the present invention. The hydraulic oil tank heating method is not described as a technical solution of the present invention.
[0033] The heating method of the pilot oil circuit is as follows:
[0034] The power source 1 and the hydraulic pump 2 are in working state. At this time, the solenoid valve 9 and the electric proportional pressure reducing valve are not energized and are in the closed state. The pilot oil provided by the hydraulic pump 2 returns to the hydraulic oil tank 4 from the relief valve 3. At this time, the pilot oil circuit is not heated. At the same time, the controller receives the oil temperature signal collected by the first temperature sensor 5 and the second temperature sensor 8, and detects the current temperature. Figure 2 shown.
[0035] (1) When T1 ≥ t1, the controller determines that the current pilot oil temperature meets the conditions for starting the pilot oil circuit, and the controller issues a prompt message "Allow the pilot valve to start"; where T1 represents the outlet oil temperature of the last group of pilot control units collected by the second temperature sensor 8, and t1 represents the temperature threshold for allowing the pilot valve to start.
[0036] (2) When T1<t1, and T0≥t0>t1, the controller issues a prompt message "The pilot oil temperature is low, and the pilot heating program is allowed to start". The controller sends a control signal to the solenoid valve 9, and the solenoid valve 9 is energized. The pilot oil flows through the electric proportional pressure reducing valve and its valve seat in each pilot control unit back to the hydraulic oil tank 4 to heat the pilot oil circuit. Since the hydraulic oil in the hydraulic oil tank 4 has been heated to temperature t0, after a certain period of circulation, the low-temperature pilot oil in the pilot oil circuit is replaced by the high-temperature hydraulic oil in the hydraulic oil tank 4, and the oil temperature of the pilot oil circuit rises. When T1≥t1, the controller determines that the current pilot oil temperature meets the conditions for starting the pilot oil circuit. The controller sends a control signal to the solenoid valve 9, and the solenoid valve 9 loses power, the pilot oil circuit is cut off, and the controller issues a prompt message "The pilot oil has been heated, and the pilot valve is allowed to start". Since the second temperature sensor 8 is arranged at the rear end of the last group of pilot control units in the pilot oil circuit, when the temperature there is t1, it can be ensured that the temperature of the entire pilot oil circuit has reached the set temperature. When the controller sends a prompt message, the controller can also use a display device to prompt the user, allowing the user to manually trigger the pilot heating program, and when the user manually triggers the pilot heating program key or button, the pilot circuit heating is completed. Wherein, T0 represents the oil temperature in the hydraulic oil tank 4 collected by the first temperature sensor 5, and t0 represents the set preheating temperature of the hydraulic oil in the hydraulic oil tank 4.
[0037] (3) When T1<t1, and T0<t0, t0>t1, the controller issues a prompt message "The oil tank temperature is low, please heat the hydraulic oil tank first". The controller monitors the temperature values collected by the first temperature sensor 5 and the second temperature sensor 8 in real time, and enters the corresponding control process when the temperature reaches condition (1) or (2), otherwise it continues to display the current prompt message.
[0038] The present invention Figure 1 The topological structure of the pilot oil circuit of the hydraulic system shown in the figure only illustrates the arrangement relationship of three groups of pilot control units (electric proportional pressure reducing valve and its valve seat). Theoretically, any number of pilot control units can be connected in series between the electric proportional pressure reducing valve PV3 and its valve seat B3 and the second temperature sensor 8 in this way. Figure 3 When some electric proportional pressure reducing valves in the pilot system are limited in their layout on the vehicle, they cannot be installed according to the Figure 1 When the topology shown is arranged, it can be arranged according to Figure 3 The principle shown in the figure is expanded, in which the electric proportional pressure reducing valve and its valve seat, temperature sensor and solenoid valve are arranged according to the characteristics of the above topological structure. The control method and control process of the extended pilot oil circuit are consistent with the above. Since the extended circuit adds a solenoid valve and a temperature sensor, its cost is higher than Figure 1 The pilot circuit shown, therefore Figure 1 It is a preferred embodiment of the present invention.
[0039] The topological structure of the present invention, i.e., the arrangement of the pilot oil circuit, clarifies the connection between each component, especially the electric proportional pressure reducing valve and its valve seat, the temperature sensor, and the solenoid valve. This topological structure can minimize the number of temperature sensors and solenoid valves and reduce system costs. At the same time, the electric proportional pressure reducing valve in the pilot oil circuit is integrated on the valve seat, and the oil passage between the valve seat oil inlet and the electric proportional pressure reducing valve oil inlet is optimized and designed to have a small cavity, so as to avoid a large amount of hydraulic oil remaining inside, and there will be no heating "dead corner" when the pilot system is heated.
[0040] The pilot system heating method proposed in the present invention can quickly increase the oil temperature of the pilot oil circuit. When the temperature of the pilot oil circuit reaches the temperature threshold t1 that allows the pilot valve to start, the pilot valve, i.e., the electric proportional pressure reducing valve, is started at this time, which can greatly improve the system response speed and improve its responsiveness.
[0041] Embodiment 2
[0042] Based on the topological structure of a pilot oil circuit of a hydraulic system described in Example 1, this embodiment provides a heating method for the pilot oil circuit, wherein the pilot oil circuit adopts the topological structure of the pilot oil circuit of the hydraulic system described in Example 1, and the heating method comprises:
[0043] Collect the oil temperature detected by the first temperature sensor 5 and the second temperature sensor 8;
[0044] The collected oil temperature is compared with the set oil temperature threshold, and the corresponding control logic is executed according to the comparison result to complete the heating of the pilot oil circuit, including:
[0045] When T1≥t1, the controller determines that the current pilot oil temperature meets the conditions for starting the pilot oil circuit, and the controller issues a prompt message "Allow the pilot valve to start"; wherein T1 represents the outlet oil temperature of the last group of pilot control units collected by the second temperature sensor 8, and t1 represents the temperature threshold for allowing the pilot valve to start;
[0046] When T1<t1, and T0≥t0>t1, the controller sends a prompt message "the pilot oil temperature is low, and the pilot heating program is allowed to start", and the controller sends a control signal to the solenoid valve 9, the solenoid valve 9 is energized, and the pilot oil flows through the electric proportional pressure reducing valve and its valve seat in each pilot control unit back to the hydraulic oil tank 4, heating the pilot oil circuit, and the oil temperature of the pilot oil circuit rises. When T1≥t1, the controller determines that the current pilot oil temperature meets the conditions for starting the pilot oil circuit, and the controller sends a control signal to the solenoid valve 9, the solenoid valve 9 loses power, and the pilot oil circuit is cut off. At the same time, the controller sends a prompt message "the pilot oil has been heated, and the pilot valve is allowed to start"; wherein, T0 represents the oil temperature in the hydraulic oil tank 4 collected by the first temperature sensor 5, and t0 represents the set preheating temperature of the hydraulic oil in the hydraulic oil tank 4;
[0047] When T1<t1, and T0<t0, t0>t1, the controller issues a prompt message "The oil tank temperature is low, please heat the hydraulic oil tank first".
[0048] Embodiment 3
[0049] Based on the topological structure of a pilot oil circuit of a hydraulic system described in the first embodiment, this embodiment provides an engineering machine, wherein the engineering machine is equipped with the topological structure of a pilot oil circuit of a hydraulic system described in the first embodiment.
[0050] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A topological structure of a pilot oil circuit of a hydraulic system, characterized in that: include: A hydraulic pump (2), wherein the inlet of the hydraulic pump (2) is connected to a hydraulic oil tank (4), the outlet of the hydraulic pump (2) is connected to the inlet of a pressure reducing valve (7), and the outlet of the pressure reducing valve (7) is connected in parallel to a plurality of pilot control modules; Each group of pilot control modules includes: A solenoid valve (9) and a plurality of pilot control units connected in series between the outlet of the pressure reducing valve (7) and the inlet of the solenoid valve (9); Each group of the pilot control units comprises: An electric proportional pressure reducing valve and a control chamber are arranged on a valve seat; in each group of pilot control units, the outlet of the electric proportional pressure reducing valve is connected to the inlet of the control chamber, and the outlet of the control chamber is connected to the inlet of the electric proportional pressure reducing valve in the next group of pilot control units; wherein the inlet of the electric proportional pressure reducing valve in the first group of pilot control units is connected to the outlet of the pressure reducing valve (7), and the outlet of the control chamber in the last group of pilot control units is connected to the inlet of the solenoid valve (9); Among them, the electric proportional pressure reducing valve works when powered on. Its input is an electrical signal and its output is a pressure signal. The output hydraulic oil enters the control chamber to drive the actuator in the control chamber to move.
2. The topological structure of the pilot oil circuit of the hydraulic system according to claim 1 is characterized in that: It also includes a second temperature sensor (8) for collecting the outlet oil temperature of the last group of pilot control units and a first temperature sensor (5) for collecting the oil temperature in the hydraulic oil tank (4).
3. The topological structure of the pilot oil circuit of the hydraulic system according to claim 1 is characterized in that: When the solenoid valve (9) is not energized, the pilot oil is cut off at the solenoid valve (9); when energized, the pilot oil circuit is connected to the hydraulic oil tank (4), and the pilot oil directly returns to the hydraulic oil tank (4).
4. The topological structure of the pilot oil circuit of the hydraulic system according to claim 1 is characterized in that: It also comprises an overflow valve (3), the inlet of the overflow valve (3) being connected to the outlet of the hydraulic pump (2), and the outlet of the overflow valve (3) being connected to the hydraulic oil tank (4).
5. The topological structure of the pilot oil circuit of the hydraulic system according to claim 1, characterized in that: It also includes an accumulator (6) arranged between the outlet of the hydraulic pump (2) and the inlet of the pressure reducing valve (7).
6. The topological structure of the pilot oil circuit of the hydraulic system according to claim 1, characterized in that: The power source (1) for driving the hydraulic pump (2) to operate comprises an engine, a power take-off device or an electric motor connected to the engine.
7. The topological structure of the pilot oil circuit of the hydraulic system according to claim 1, characterized in that: The electric proportional pressure reducing valve and its valve seat are connected by a pipeline. The electric proportional pressure reducing valve is integrated on the valve seat. The oil inlet of the valve seat and the oil inlet of the electric proportional pressure reducing valve are connected by an optimized oil channel with a volume cavity smaller than a set threshold value, so as to avoid hydraulic oil retention and improve the preheating effect.
8. A method for heating a pilot oil circuit, characterized in that: The pilot oil circuit adopts the topological structure of the pilot oil circuit of the hydraulic system according to any one of claims 2 to 7, and the heating method comprises: collecting the oil temperature detected by the first temperature sensor (5) and the second temperature sensor (8); The collected oil temperature is compared with the set oil temperature threshold, and the corresponding control logic is executed according to the comparison result to complete the heating of the pilot oil circuit.
9. The method for heating the pilot oil circuit according to claim 8, characterized in that: The collected oil temperature is compared with the set oil temperature threshold, and the corresponding control logic is executed according to the comparison result, including: When T1≥t1, the controller determines that the current pilot oil temperature meets the conditions for starting the pilot oil circuit, and the controller issues a prompt message "allow pilot valve to start"; wherein T1 represents the outlet oil temperature of the last group of pilot control units collected by the second temperature sensor (8), and t1 represents the temperature threshold for allowing the pilot valve to start; When T1<t1, and T0≥t0>t1, the controller sends a prompt message "the pilot oil temperature is low, and the pilot heating program is allowed to start", and the controller sends a control signal to the solenoid valve (9), the solenoid valve (9) is energized, and the pilot oil flows through the electric proportional pressure reducing valve and its valve seat in each pilot control unit back to the hydraulic oil tank (4), heating the pilot oil circuit, and the oil temperature of the pilot oil circuit rises. When T1≥t1, the controller determines that the current pilot oil temperature meets the conditions for starting the pilot oil circuit, and the controller sends a control signal to the solenoid valve (9), the solenoid valve (9) loses power, the pilot oil circuit is cut off, and the controller sends a prompt message "the pilot oil has been heated, and the pilot valve is allowed to start"; wherein T0 represents the oil temperature in the hydraulic oil tank (4) collected by the first temperature sensor (5), and t0 represents the set preheating temperature of the hydraulic oil in the hydraulic oil tank (4); When T1<t1, and T0<t0, t0>t1, the controller issues a prompt message "The oil tank temperature is low, please heat the hydraulic oil tank first".
10. An engineering machine, characterized in that: The engineering machinery is equipped with a topological structure of a pilot oil circuit of a hydraulic system as claimed in any one of claims 1 to 7.