Fan control hydraulic system and engineering machinery with same

Abstract

The utility model relates to a fan control hydraulic system for engineering machinery, which comprises an oil tank, a hydraulic pump connected with the oil tank, and a fan motor connected with the output end of the hydraulic pump and used for driving a fan to rotate, and is characterized in that the fan control hydraulic system comprises a hydraulic control valve group connected with the fan motor in parallel; the hydraulic control valve group comprises a switching valve and a first overflow valve which are arranged on a first pressure control branch in series; the first overflow valve is arranged on the first pressure control branch, the second overflow valve is arranged on the second pressure control branch, the first pressure control branch and the second pressure control branch are arranged in parallel, and the overflow pressure of the first overflow valve is smaller than that of the second overflow valve. The utility model further relates to engineering machinery with the fan control hydraulic system.

Description

Technical Field

[0001] The utility model relates to the field of hydraulic systems of engineering machinery, in particular to a fan control hydraulic system for engineering machinery and engineering machinery with the fan control hydraulic system. Background Art

[0002] There are many forms of hydraulic cooling for construction machinery. For the application of quantitative hydraulic system in fan cooling, the commonly used systems are roughly divided into the following two types: 1) A hydraulic system including a gear pump, a fixed relief valve and a gear motor, in which the maximum oil inlet pressure of the fan motor is controlled by the relief valve setting value, thereby limiting the maximum fan speed. The advantages of this system are that the system is simple, the cost is low, and it is widely used in the construction machinery industry; the disadvantage is that the maximum speed cannot be adjusted. Regardless of the load of the whole machine, when the engine exceeds a certain speed, the fan will maintain a fixed number of revolutions, and the energy consumption is large; 2) A system including a gear pump, an electric proportional relief valve and a gear motor, in which multiple sensors are used to collect signals such as water temperature, transmission oil temperature, and hydraulic oil temperature. These signals will be transmitted to the engine control module. Different signal settings have different limits. The engine control module adjusts the control valve core opening at different temperature points through software settings, thereby controlling the flow delivered to the fan motor. The advantages of this system are that it is highly intelligent and energy-saving. The disadvantage is that it is expensive.

[0003] Therefore, the present invention is dedicated to one or more improvements to the prior art. Utility Model Content

[0004] In view of the defects of the prior art, the utility model proposes an improved technology for a fan control hydraulic system of engineering machinery, which enables a fan control hydraulic system with reasonable cost and easy control to be obtained.

[0005] According to one aspect of the utility model, a fan control hydraulic system for engineering machinery is provided, comprising an oil tank, a hydraulic pump connected to the oil tank through a pipeline, and a fan motor connected to the output end of the hydraulic pump and driving the fan to rotate, the fan structure being used to cool the fluid flowing in the radiator of the hydraulic cooling system of the engineering machinery, and being characterized in that the fan control hydraulic system comprises a hydraulic control valve group arranged in parallel with the fan motor, the hydraulic control valve group comprising: a switch valve and a first overflow valve arranged in series on a first pressure control branch; and a second overflow valve arranged on a second pressure control branch, the first pressure control branch and the second pressure control branch being arranged in parallel, and the overflow pressure of the first overflow valve being less than the overflow pressure of the second overflow valve.

[0006] Advantageously, the fan control hydraulic system further comprises a controller signal-connected to the switch valve, the controller being configured to control opening and closing of the switch valve based on a detection signal indicative of engine load.

[0007] Advantageously, the fan control hydraulic system comprises a sensor for detecting a cooling water temperature at an outlet of an engine thermostat in an engine cooling system, and the detection signal indicative of the engine load comprises a temperature signal from the sensor.

[0008] Advantageously, the controller is configured to switch the switch valve from an open state to a closed state when the engine cooling water temperature from the sensor is greater than a predetermined threshold, and to switch the switch valve from a closed state to an open state when the engine cooling water temperature from the sensor is less than or equal to the predetermined threshold.

[0009] Advantageously, the hydraulic pump is driven by the engine.

[0010] Advantageously, the radiator comprises a hydraulic oil radiator arranged downstream of the fan motor.

[0011] Advantageously, the switch valve is a solenoid switch valve.

[0012] Advantageously, the switch valve is arranged upstream of the first overflow valve.

[0013] According to another aspect of the utility model, a construction machine is provided, wherein the construction machine comprises the above-mentioned fan control hydraulic system.

[0014] According to the utility model, by providing a first overflow valve and a second overflow valve and controlling the switch valve connected in series with the first overflow valve based on a detection signal indicating the engine load, the fan motor can be switched between two control level speeds according to the load conditions of the hydraulic and transmission systems, thereby overcoming the problems of the prior art that the fan has only a single maximum control speed and is rough and energy-consuming, and the prior art fan control is complex and costly. In addition, by using a single sensor for detecting the engine cooling water temperature to evaluate the heat generation of the hydraulic system and the transmission system, the number of sensors set is reduced, and the system cost is further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Exemplary embodiments of the present invention are described with reference to the accompanying drawings, in which:

[0016] Figure 1 It is a schematic diagram of a fan control hydraulic system for engineering machinery of the utility model;

[0017] Figure 2 A schematic diagram of a hydraulic control valve group of a fan control hydraulic system for engineering machinery according to the utility model is shown.

[0018] Reference numerals:

[0019] 1- fan control hydraulic system; 1101- first overflow valve;

[0020] H-oil tank; L2-second pressure control branch;

[0021] FP-hydraulic pump; 1102-second overflow valve;

[0022] FM-fan motor; 12-controller;

[0023] R-hydraulic oil radiator; S-sensor;

[0024] 11- hydraulic control valve group; P- input end of hydraulic control valve group;

[0025] L1-first pressure control branch; T-output end of hydraulic control valve group;

[0026] SW-switching valve; CW-cooling water.

[0027] The accompanying drawings are only schematic and not necessarily drawn to scale, and they only show those parts necessary to illustrate the utility model, and other parts are omitted or only mentioned. That is, in addition to the parts shown in the accompanying drawings, the utility model may also include other parts. DETAILED DESCRIPTION

[0028] The technical solution of the utility model is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth so that the technical personnel in the relevant technical field can more fully understand the utility model. However, it is obvious to the technical personnel in the relevant technical field that the implementation of the utility model may not have some of these specific details. In addition, it should be understood that the utility model is not limited to the specific embodiments introduced. On the contrary, it can be considered to implement the utility model with any combination of the following features and elements, whether or not they relate to different embodiments.

[0029] Figure 1 The schematic diagram of the fan control hydraulic system 1 for engineering machinery of the utility model is shown. The fan control hydraulic system 1 includes an oil tank H, a hydraulic pump FP connected to the oil tank H, and a fan motor FM connected to the output end of the hydraulic pump FP and driving the fan to rotate. A hydraulic oil radiator R is connected downstream of the fan motor FM. In the hydraulic oil radiator R, the hydraulic oil discharged from the fan motor exchanges heat with the airflow forced to flow by the fan, thereby cooling the hydraulic oil. The cooled hydraulic oil flows out of the radiator and returns to the oil tank H. The fan can also force the airflow to flow through other radiators in the hydraulic cooling system of the engineering machinery, such as a lubricating oil radiator, an engine cooling pack, etc. The hydraulic pump is advantageously driven by the engine.

[0030] The fan control hydraulic system 1 according to the present invention comprises a hydraulic control valve group 11 arranged in parallel with the fan motor FM. Figure 1 and Figure 2 As shown, the input end P of the hydraulic control valve group is connected to the output end of the hydraulic pump. The output end T of the hydraulic control valve group is connected to the output end of the fan motor FM. The hydraulic control valve group 11 includes: a switch valve SW and a first overflow valve 1101 arranged in series on the first pressure control branch L1; and a second overflow valve 1102 arranged on the second pressure control branch L2, and the first pressure control branch L1 and the second pressure control branch L2 are arranged in parallel. The overflow pressure of the first overflow valve 1101 is less than the overflow pressure of the second overflow valve 1102. The first overflow valve serves to limit the first maximum speed of the fan motor. The second overflow valve serves to limit the second maximum speed of the fan motor. The first maximum speed is less than the second maximum speed. The switch valve SW is, for example, an electromagnetic switch valve. In the illustrated embodiment, the switch valve SW is arranged upstream of the first overflow valve 1101.

[0031] According to the present invention, the fan control hydraulic system 1 further comprises a controller 12 connected to the switch valve SW signal. The controller is, for example, an engine control module (ECM). The controller is configured to control the opening and closing of the switch valve based on a detection signal indicating the engine load.

[0032] In an advantageous embodiment according to the present invention, the fan control hydraulic system 1 includes a sensor S for detecting the temperature of the cooling water CW at the engine thermostat (not shown) in the engine cooling system (preferably after the thermostat or at the thermostat outlet). The sensor S is signal-connected to the controller 12 to transmit the temperature signal indicating the engine cooling water temperature detected by the sensor S to the controller 12 as a detection signal indicating the engine load.

[0033] In an advantageous embodiment, the controller 12 is configured to switch the switch valve SW from an open state to a closed state when the engine cooling water temperature from the sensor is greater than a predetermined threshold, and to switch the switch valve SW from a closed state to an open state when the engine cooling water temperature from the sensor is less than or equal to the predetermined threshold. Advantageously, the switch valve SW is a normally open solenoid valve, that is, the solenoid valve remains in an open position when power is lost, and is in a closed position when power is obtained.

[0034] Refer to the following Figure 1 The working principle of the fan control hydraulic system 1 of the present invention is described.

[0035] The hydraulic pump FP provides pressurized oil to drive the fan motor FM to rotate, and the fan rotates with the fan motor. The oil discharged by the fan motor returns to the oil tank through the hydraulic oil radiator R.

[0036] When the whole machine is under low load and the engine cooling water temperature is lower than the engine thermostat opening temperature, the sensor S is in an inactive state. The switch valve SW is in the normally open position. At this time, the first relief valve 1101 in the control valve group will limit the maximum oil inlet pressure of the fan motor. When the engine speed increases, the speed of the hydraulic pump FP increases accordingly, and the speed of the fan motor FM increases accordingly. The fan load also increases, and the oil inlet pressure of the fan motor increases. When the engine speed reaches a certain value, the oil inlet pressure of the fan motor will force the first relief valve 1101 to enter the open position. The first relief valve in the open position will play a role in limiting the working pressure of the fan motor. When the first relief valve plays a limiting role, even if the engine speed increases again, the speed of the fan motor will remain at the first constant value.

[0037] When the whole machine load increases, the power consumed by the engine increases, and the engine cooling water temperature rises accordingly. When the engine cooling water temperature is higher than the engine thermostat opening temperature, the sensor S is in an activated state, and the engine cooling water temperature signal detected by the sensor is sent to the controller 12.

[0038] When the engine cooling water temperature detected by the sensor is greater than a predetermined threshold, the controller 12 sends a control signal to the switch valve SW to switch the switch valve from the normally open position to the closed position, and the first pressure control branch is disconnected. At this time, the first overflow valve 1101 will also be in the closed position.

[0039] As the engine speed further increases, the hydraulic pump speed and the fan motor speed further increase, and the pressure at the fan motor oil inlet further increases. When the pressure at the fan motor oil inlet increases to a certain value, the second relief valve 1102 is forced to open, and the second relief valve in the open position will play a role in limiting the working pressure of the fan motor. When the second relief valve 1102 plays a limiting role, even if the engine speed increases further, the fan speed will remain at a second constant value that is higher than the first constant value.

[0040] When the whole machine returns to low load, the engine cooling water temperature drops. The controller 12 continues to control the switch valve SW based on the engine cooling water temperature signal detected by the sensor. When the detected engine cooling water temperature is less than or equal to the predetermined threshold, the controller 12 sends a control signal to the switch valve to de-energize the switch valve SW, and the switch valve SW switches from the closed state to the open state. At this time, the first relief valve 1101 again plays the role of limiting the working pressure of the fan motor.

[0041] Thus, dual-stage control of fan speed can be achieved at a lower cost and in an effective and simple manner.

[0042] Although the embodiment shown in the figure uses a sensor to detect the engine cooling water temperature to determine the load conditions of the hydraulic and transmission systems and the engine, it is understandable that other means can also be used to obtain a detection signal indicating the engine load, for example, using a sensor to detect the oil temperature at the oil inlet of the hydraulic oil radiator and the water temperature of the cooling water at the radiator inlet of the engine cooling system, and the like, and comprehensively determine the engine load condition based on the detected temperatures. The utility model detects the engine cooling water temperature by a single temperature sensor, which reduces the component cost and control cost.

[0043] The fan control hydraulic system of the utility model can control the fan speed at a reasonable cost, is energy-saving and economical, and has convenient and reliable control.

[0044] Industrial Applicability

[0045] In order to better understand the present invention, Figure 1 The fan control hydraulic system shown is taken as an example to illustrate the specific working principle of the utility model.

[0046] exist Figure 1 In the fan control hydraulic system shown, the engine cooling water temperature is detected by a single temperature sensor. The load conditions of the hydraulic and transmission systems and the engine are judged based on the detected engine cooling water temperature. The hydraulic and transmission power inputs are derived from the power output of the engine. When the load is light, the hydraulic and transmission power outputs are small, and the engine load output will also be small, which means that the engine cooling water temperature is low. When the hydraulic or transmission output is heavy, the engine load increases, and the engine cooling water temperature rises accordingly. When problems arise during the operation of the hydraulic system or the transmission system, the temperature rise of the engine cooling water will increase. The utility model evaluates the heat generation of the hydraulic system and the transmission system by detecting the engine cooling water temperature, which greatly simplifies the control difficulty.

[0047] Specifically, when the whole machine is under low load, as the engine load increases, the heat dissipation demand increases. At this time, the switch valve SW is in the open state, and the first pressure control branch L1 of the hydraulic control valve group 11 plays a role in limiting the working pressure of the fan motor. When the whole machine load increases and the engine power consumption increases, the engine cooling water temperature increases to exceed the predetermined threshold value, and the controller controls the switch valve SW to switch it to the closed state, thereby making the first pressure control branch L1 inoperative ("sleeping"), and switching the second pressure control branch L2 to an operative state ("awakening"), that is, limiting the working pressure of the fan motor through the second overflow valve 1102. When the engine load decreases, the engine cooling water temperature drops to less than or equal to the predetermined threshold value, and the controller controls the switch valve SW to switch it to the open state. At this time, the first pressure control branch L1 enters the awakening state, and the second pressure control branch L2 automatically enters the dormant state.

[0048] Through the simple configuration of the hydraulic control valve group of the utility model, the fan motor and the fan speed can be controlled in stages (two-stage) according to the load conditions of the whole machine economically and effectively.

[0049] The fan control hydraulic system according to the utility model can be used in engineering machinery such as excavators to achieve desired work and operation.

[0050] The above exemplary embodiments have made a clear and complete description of the utility model. It should be understood by those skilled in the art that various other embodiments can be conceived by modifying the disclosed technical solutions without departing from the spirit and scope of the utility model. These embodiments should be understood to fall within the scope of the utility model determined based on the claims and any equivalent technical solutions thereof.

Claims

1. A fan control hydraulic system for engineering machinery, comprising an oil tank, a hydraulic pump connected to the oil tank, and a fan motor connected to the output end of the hydraulic pump and driving the fan to rotate, wherein the fan is configured to cool the fluid flowing in the radiator of the hydraulic cooling system of the engineering machinery, It is characterized in that The fan control hydraulic system includes a hydraulic control valve group arranged in parallel with the fan motor, and the hydraulic control valve group includes: a switch valve and a first overflow valve arranged in series on a first pressure control branch; and a second overflow valve arranged on a second pressure control branch. The first pressure control branch and the second pressure control branch are arranged in parallel, and the overflow pressure of the first overflow valve is less than the overflow pressure of the second overflow valve.

2. The fan control hydraulic system according to claim 1, characterized in that: The fan control hydraulic system further includes a controller signal-connected to the switch valve, the controller being configured to control opening and closing of the switch valve based on a detection signal indicative of an engine load.

3. The fan control hydraulic system according to claim 2, characterized in that: The fan control hydraulic system includes a sensor for detecting a cooling water temperature at an outlet of an engine thermostat in an engine cooling system, and the detection signal indicating the engine load includes a temperature signal from the sensor.

4. The fan control hydraulic system according to claim 3, characterized in that: The controller is configured to switch the switch valve from an open state to a closed state when the engine cooling water temperature from the sensor is greater than a predetermined threshold, and to switch the switch valve from a closed state to an open state when the engine cooling water temperature from the sensor is less than or equal to the predetermined threshold.

5. The fan control hydraulic system according to any one of claims 1 to 4, characterized in that: The hydraulic pump is driven by the engine.

6. The fan control hydraulic system according to any one of claims 1 to 4, characterized in that: The radiator includes a hydraulic oil radiator disposed downstream of the fan motor.

7. The fan control hydraulic system according to any one of claims 1 to 4, characterized in that: The switch valve is an electromagnetic switch valve.

8. The fan control hydraulic system according to claim 7, characterized in that: The switch valve is arranged upstream of the first relief valve.

9. An engineering machine, characterized in that: The engineering machine comprises a fan control hydraulic system according to any one of claims 1-8.

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