Heat dissipation hydraulic system and engineering equipment

Abstract

The utility model provides a heat dissipation hydraulic system and engineering equipment, wherein the heat dissipation hydraulic system comprises a pump, an oil tank, an electromagnetic proportional valve group, a hydraulic motor and a fan in driving connection with the hydraulic motor, the electromagnetic proportional valve group comprises an electromagnetic directional valve, the electromagnetic directional valve is provided with a first working position, a second working position and a third working position, the second working position is provided with a first throttle valve and a second throttle valve; two oil ports of the hydraulic motor are respectively connected with the electromagnetic directional valve, and the pump is connected with an oil inlet of the electromagnetic proportional valve group; when the electromagnetic reversing valve is located at a first working position, the hydraulic motor enters oil in the forward direction, and the fan rotates in the forward direction; when the electromagnetic reversing valve is located at the second working position, oil of the hydraulic motor is throttled through the first throttling valve or the second throttling valve and then is connected with the oil tank, so that the fan is static; when the electromagnetic reversing valve is located at the third working position, oil enters the hydraulic motor in the reverse direction, the fan rotates reversely, hydraulic pressure relief buffering can be provided for reversing of the fan, and parts are prevented from being damaged.

Description

Technical Field

[0001] The utility model relates to the technical field of heat dissipation of hydraulic systems, in particular to a heat dissipation hydraulic system and engineering equipment. Background Art

[0002] At present, more and more excavators are using independent cooling. This can not only meet the performance requirements of the excavator, but also control the cooling system more accurately and energy-efficiently. In order to meet the market demand, the cooling system of some large excavators has adopted a forward and reverse independent cooling control system. However, the existing forward and reverse independent cooling control system has the following two obvious defects:

[0003] 1. When the actuator hydraulic motor is switched between forward and reverse rotation, the impact caused by excessive hydraulic oil pressure is large, which causes great damage to the hydraulic motor and fan; or when the actuator hydraulic motor is switched between forward and reverse rotation, the engine needs to be turned off, and then the excavator is powered on, and then the hydraulic motor is switched between forward and reverse rotation, and then the engine is started. This operation method is too cumbersome;

[0004] 2. The hydraulic pumps (including plunger pumps and gear pumps) that provide power to the hydraulic motors are equipped with electric proportional relief valves. The lowest adjustable pressure is generally around 20 Bar, and some products even have 50 Bar. Under this pressure condition, the fan will still rotate at high speed. When the weather is cold, the power system and hydraulic system of the excavator are already at low temperatures, and the fan is still performing heat dissipation operations, which has a certain impact on the performance of the entire excavator and wastes energy.

[0005] Therefore, there is an urgent need for a heat dissipation hydraulic system and engineering equipment that can overcome the above-mentioned technical defects. Utility Model Content

[0006] The utility model aims to provide a heat dissipation hydraulic system and engineering equipment, aiming to solve the technical problems of the traditional independent heat dissipation control system that is easy to cause hydraulic shock to damage parts and the forward and reverse operation is troublesome.

[0007] To achieve the above-mentioned purpose, in a first aspect, the utility model provides a heat dissipation hydraulic system, including a pump, an oil tank, an electromagnetic proportional valve group, a hydraulic motor and a fan drivingly connected to the hydraulic motor.

[0008] The electromagnetic proportional valve group includes an electromagnetic reversing valve, the electromagnetic reversing valve has a first working position, a second working position and a third working position, and the second working position is provided with a first throttle valve and a second throttle valve;

[0009] The two oil ports of the hydraulic motor are respectively connected to the electromagnetic reversing valve, and the pump is connected to the oil inlet of the electromagnetic proportional valve group;

[0010] When the electromagnetic reversing valve is in the first working position, under the action of the pump, the hydraulic motor is supplied with oil in a positive direction, and the fan rotates forward under the positive drive of the hydraulic motor;

[0011] When the electromagnetic reversing valve is in the second working position, the oil of the hydraulic motor is connected to the oil tank after being throttled by the first throttle valve or the second throttle valve, so that the fan is switched from a moving state to a stationary state;

[0012] When the electromagnetic reversing valve is in the third working position, under the action of the pump, the hydraulic motor supplies oil in the reverse direction, and the fan is reversed under the reverse drive of the hydraulic motor.

[0013] As a further improvement of the above scheme, the solenoid reversing valve is a three-position four-way solenoid proportional reversing valve, and a first working oil port, a second working oil port, a reversing oil inlet port and a reversing oil return port are provided on its valve body. The first working oil port and the second working oil port are respectively connected to the two oil ports of the hydraulic motor, the reversing oil inlet port is connected to the oil inlet port of the solenoid proportional valve group, and the reversing oil return port is connected to the oil tank.

[0014] As a further improvement of the above scheme, the electromagnetic proportional valve group also includes an electric proportional overflow valve, which has a first overflow port and a second overflow port. The first overflow port is connected to the oil inlet of the electromagnetic proportional valve group, and the second overflow port is connected to the oil tank.

[0015] As a further improvement of the above scheme, the electromagnetic proportional valve group also includes an oil replenishing one-way valve, which is arranged between the reversing oil return port and the reversing oil inlet port, and is unidirectionally conductive from the reversing oil return port to the reversing oil inlet port, and is used to replenish oil when the hydraulic motor is sucked empty.

[0016] As a further improvement of the above scheme, the heat dissipation hydraulic system also includes a controller and a display, the display is electrically connected to the controller, the electromagnetic reversing valve is electrically connected to the controller, and the electric proportional relief valve is electrically connected to the controller.

[0017] As a further improvement of the above solution, the neutral position function of the electromagnetic reversing valve is H type.

[0018] In a second aspect, the present invention further provides an engineering equipment, comprising the above-mentioned heat dissipation hydraulic system.

[0019] Since the utility model adopts the above technical solution, the beneficial effects of this application are:

[0020] The utility model provides a heat dissipation hydraulic system, comprising a pump, an oil tank, an electromagnetic proportional valve group, a hydraulic motor and a fan connected to the hydraulic motor drive, the electromagnetic proportional valve group comprising an electromagnetic reversing valve, the electromagnetic reversing valve having a first working position, a second working position and a third working position, the second working position being provided with a first throttle valve and a second throttle valve; the two oil ports of the hydraulic motor are respectively connected to the electromagnetic reversing valve, the pump is connected to the oil inlet of the electromagnetic proportional valve group; when the electromagnetic reversing valve is in the first working position, under the action of the pump, the hydraulic motor is forwardly fed with oil, and the fan is driven in the forward direction of the hydraulic motor When the electromagnetic reversing valve is in the second working position, the oil of the hydraulic motor is throttled by the first throttle valve or the second throttle valve and connected to the oil tank, so that the fan is converted from a moving state to a stationary state; when the electromagnetic reversing valve is in the third working position, under the action of the pump, the hydraulic motor reverses the oil flow, and the fan reverses under the reverse drive of the hydraulic motor; such a setting, when working normally, the left electromagnet of the electromagnetic reversing valve is energized, the electromagnetic reversing valve is in the first working position, and after the pump is started, the pump provides hydraulic pressure and drives the hydraulic motor to rotate, thereby driving the fan to rotate for heat dissipation;

[0021] In cold weather, when the temperatures of water cooling, air cooling and hydraulic oil cooling are all at low temperatures and there is no need for the fan to rotate to dissipate heat, the left and right electromagnets of the electromagnetic reversing valve are both de-energized, and the valve core of the electromagnetic reversing valve is in the middle position, that is, in the second working position, and the hydraulic oil directly returns to the oil tank through the second throttle valve, thereby reducing energy waste;

[0022] When the back-blowing function is needed, if the right electromagnet of the electromagnetic reversing valve is directly energized, the fan is still in high-speed forward rotation at this time, the inertia of the fan is large, and direct switching will generate a large reverse hydraulic pressure, which will have a great impact on the hydraulic motor and the fan, thereby possibly damaging the components; when the hydraulic heat dissipation system provided by the utility model is used for reverse heat dissipation, first the left electromagnet and the right electromagnet of the electromagnetic reversing valve are both de-energized, the valve core of the electromagnetic reversing valve is in the middle position, that is, in the second working position, the second throttle valve in the electromagnetic reversing valve increases the return oil back pressure, which can allow the fan to stop completely in a shorter time without hydraulic shock, thereby avoiding damage to components, and then the right electromagnet of the electromagnetic reversing valve is energized, the hydraulic motor reverses the oil flow, and the fan The fan reverses from a stationary state under the reverse drive of the hydraulic motor; when the forward blowing function is needed again, the left electromagnet and the right electromagnet of the electromagnetic reversing valve are first de-energized to put it in the second working position, and the first throttle valve in the electromagnetic reversing valve increases the return oil back pressure, which can allow the fan to completely stop in a shorter time, and then the left electromagnet of the electromagnetic reversing valve is energized, and the hydraulic motor is forwardly supplied with oil, and the fan rotates forward from a stationary state under the forward drive of the hydraulic motor, and so on. Whenever forward and reverse switching is required, the left electromagnet and the right electromagnet of the electromagnetic reversing valve are first de-energized to provide hydraulic pressure relief buffer, and then switch, which can avoid hydraulic shock and thus avoid damage to parts; and the operation is convenient, and only the corresponding switching buffer control time needs to be set in the controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0024] Figure 1 The utility model discloses a principle schematic diagram of a heat dissipation hydraulic system.

[0025] Reference numerals:

[0026] 1. Pump; 2. Oil tank; 3. Solenoid proportional valve group; 31. Solenoid reversing valve; 32. First throttle valve; 33. Second throttle valve; 35. Electric proportional relief valve; 36. Oil replenishment check valve; 4. Hydraulic motor; 5. Fan;

[0027] A, first working oil port; B, second working oil port; P0, reversing oil inlet port; T0, reversing oil return port; P, oil inlet port; a, first oil port; b, second oil port.

[0028] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] It should be noted that all directional indications (such as up, down, etc.) in the implementation mode of the utility model are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0031] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0032] Furthermore, the technical solutions between the various implementation modes of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0033] Embodiment 1:

[0034] See also Figure 1 The utility model provides a heat dissipation hydraulic system, comprising a pump 1, an oil tank 2, an electromagnetic proportional valve group 3, a hydraulic motor 4 and a fan 5 drivingly connected to the hydraulic motor 4.

[0035] The electromagnetic proportional valve group 3 includes an electromagnetic reversing valve 31, and the electromagnetic reversing valve 31 has a first working position, a second working position and a third working position, and the second working position is provided with a first throttle valve 32 and a second throttle valve 33; specifically, in the present embodiment, the electromagnetic reversing valve 31 is a three-position four-way electromagnetic proportional reversing valve, and its position function is H-type, and the first throttle valve 32 and the second throttle valve 33 are respectively provided on the passage corresponding to its position function, which is different from the two-position four-way valve commonly used in the prior art;

[0036] The two oil ports of the hydraulic motor 4 are respectively connected to the electromagnetic reversing valve 31, and the pump 1 is connected to the oil inlet P of the electromagnetic proportional valve group 3. Specifically, in the present embodiment, the valve body of the electromagnetic reversing valve 31 is provided with a first working oil port A, a second working oil port B, a reversing oil inlet P0 and a reversing oil return port T0. The first working oil port A and the second working oil port B are respectively connected to the two oil ports of the hydraulic motor 4. The first working oil port A is connected to the first oil port a of the hydraulic motor 4, and the second working oil port B is connected to the second oil port b of the hydraulic motor 4. The reversing oil inlet P0 is connected to the oil inlet P of the electromagnetic proportional valve group 3, and the reversing oil return port T0 is connected to the oil tank 2.

[0037] When the fan 5 needs to rotate forward, the electromagnet on the left side of the electromagnetic reversing valve 31 is energized. When the electromagnetic reversing valve 31 is in the first working position, under the action of the pump 1, the hydraulic motor 4 is fed with oil in the forward direction, and the fan 5 rotates forward under the forward drive of the hydraulic motor 4;

[0038] When switching is required, the left electromagnet and the right electromagnet of the electromagnetic reversing valve 31 are both de-energized. When the electromagnetic reversing valve 31 is in the second working position, the oil of the hydraulic motor 4 is throttled by the first throttle valve 32 or the second throttle valve 33 and connected to the oil tank 2, so that the fan 5 is switched from a moving state to a stationary state.

[0039] When the fan 5 needs to be reversed, the right electromagnet of the electromagnetic reversing valve 31 is energized. When the electromagnetic reversing valve 31 is in the third working position, the hydraulic motor 4 reverses oil under the action of the pump 1, and the fan 5 reverses under the reverse drive of the hydraulic motor 4;

[0040] With such a configuration, when working normally, the left electromagnet of the electromagnetic reversing valve 31 is energized, the electromagnetic reversing valve 31 is in the first working position, and after the pump 1 is started, the pump 1 provides hydraulic pressure and drives the hydraulic motor 4 to rotate, thereby driving the fan 5 to rotate for heat dissipation;

[0041] In cold weather, when the temperatures of water cooling, air cooling, and hydraulic oil cooling are all at low temperatures and the fan 5 is not needed to rotate for heat dissipation, the left and right electromagnets of the electromagnetic reversing valve 31 are de-energized, and the valve core of the electromagnetic reversing valve 31 is in the middle position, that is, in the second working position. The hydraulic oil returns directly to the oil tank 2 through the second throttle valve 33. The back pressure of the oil tank 2 is very low (generally ≤5 bar), which reduces energy waste; thereby better improving the performance and fuel economy of the vehicle. The traditional forward and reverse independent heat dissipation hydraulic system does not have a middle position function; and the lowest adjustable pressure of the electric proportional relief valve 35 is generally around 20 Bar, and some products even have 50 Bar; under this pressure condition, the fan 5 will still rotate at high speed, seriously wasting energy and resources;

[0042] When the back-blowing function is needed, if the right electromagnet of the electromagnetic reversing valve 31 is directly energized, the fan 5 is still in high-speed forward rotation at this time, and the inertia of the fan 5 is relatively large. Direct switching will generate a large reverse hydraulic pressure, which will have a great impact on the hydraulic motor 4 and the fan 5, thereby possibly damaging the components. When the hydraulic heat dissipation system provided by the utility model is used for reverse heat dissipation, the left electromagnet and the right electromagnet of the electromagnetic reversing valve 31 are first de-energized, and the valve core of the electromagnetic reversing valve 31 is in the middle position, that is, in the second working position. The second throttle valve 33 in the electromagnetic reversing valve 31 increases the return oil back pressure, which can allow the fan 5 to stop completely in a shorter time without hydraulic shock, thereby avoiding damage to components. Then the right electromagnet of the electromagnetic reversing valve 31 is energized, and the hydraulic motor 4 reverses the oil flow. The fan 5 reverses from a stationary state under the reverse drive of the hydraulic motor 4; when the forward blowing function is needed again, the left electromagnet and the right electromagnet of the electromagnetic reversing valve 31 are first de-energized to put it in the second working position, and the first throttle valve 32 in the electromagnetic reversing valve 31 increases the return oil back pressure, which can allow the fan 5 to completely stop in a shorter time, and then the left electromagnet of the electromagnetic reversing valve 31 is energized, and the hydraulic motor 4 is forwardly supplied with oil, and the fan 5 rotates forward from a stationary state under the forward drive of the hydraulic motor 4, and so on. Whenever forward and reverse switching is required, the left electromagnet and the right electromagnet of the electromagnetic reversing valve 31 are first de-energized to provide hydraulic pressure relief buffer, and then switch, which can avoid hydraulic shock and thus avoid damage to parts; and the operation is convenient, and only the corresponding switching buffer control time needs to be set in the controller.

[0043] It should be noted that when forward and reverse switching is required, the electromagnets on both sides of the electromagnetic reversing valve 31 are first de-energized to make it in the second working position, and the high-speed rotating fan 5 is stopped before switching to the corresponding passage (that is, switching to the left electromagnet of the electromagnetic reversing valve 31 or the right electromagnet is energized). Therefore, it is necessary to control the switching after reaching the preset delay time. The preset delay time here needs to be obtained through experimental testing, that is, it is necessary to test the time required for the fan 5 of the corresponding model to rotate from high speed to stop.

[0044] As a preferred embodiment, the electromagnetic proportional valve group 3 further includes an electric proportional overflow valve 35, and the electric proportional overflow valve 35 has a first overflow port and a second overflow port, the first overflow port is connected to the oil inlet P of the electromagnetic proportional valve group 3, and the second overflow port is connected to the oil tank 2;

[0045] When switching between forward and reverse directions, the neutral position function of the electromagnetic reversing valve 31 is utilized. After the fan 5 stops completely (the time for the fan 5 to stop completely needs to be determined through testing), the electromagnet on the right side of the electromagnetic reversing valve 31 is energized (the energization needs to be delayed by the program, and the delay time is determined according to the time determined by the test). At this time, the electric proportional relief valve 35 will provide the designed maximum pressure, and the speed of the fan 5 will reach the designed maximum speed for backblowing operation.

[0046] As a preferred embodiment, the electromagnetic proportional valve group 3 further includes an oil replenishment check valve 36, which is arranged between the reversing oil return port T0 and the reversing oil inlet port P0, and is unidirectionally conducted from the reversing oil return port T0 to the reversing oil inlet port P0, and is used to replenish oil when the hydraulic motor 4 is empty;

[0047] Taking an excavator as an example, when the rotary drilling head of the excavator swings back and forth when throwing soil, the hydraulic motor 4 will be short of oil supply, which will cause air suction. At this time, the oil in the oil tank 2 is connected to the oil replenishment check valve 36 under the action of atmospheric pressure, and the oil in the oil tank 2 is replenished into the oil port corresponding to the hydraulic motor 4 for oil replenishment; or the pressure oil flowing out of the reversing return oil port T0 of the electromagnetic reversing valve 31 is connected to the oil replenishment check valve 36 and enters the oil port corresponding to the hydraulic motor 4 for oil replenishment. The setting of the replenishment check valve can replenish oil in time when the hydraulic motor 4 is empty, thereby avoiding insufficient power.

[0048] As a preferred embodiment, the heat dissipation hydraulic system also includes a controller and a display, the display is electrically connected to the controller, the electromagnetic reversing valve 31 is electrically connected to the controller, and the electric proportional relief valve 35 is electrically connected to the controller; the user inputs the corresponding operation instruction by operating the display screen, and the display transmits the received operation instruction to the controller, and the controller controls the electromagnetic reversing valve 31 to switch from the first working position to the second working position, and after the preset delay time is reached, it switches from the second working position to the third working position, and so on, to achieve forward and reverse control of the fan 5, thereby avoiding hydraulic shock and reducing damage to components; the electromagnetic reversing valve 31 can also be switched to the second working position according to weather conditions, so that the oil of the hydraulic motor 4 returns directly to the oil tank 2, thereby reducing unnecessary energy loss.

[0049] Embodiment 2:

[0050] The present invention also provides an engineering equipment, including the heat dissipation hydraulic system described in Example 1. In this embodiment, the heat dissipation hydraulic system is set in the excavator of a certain model as an example for explanation. According to the heat dissipation system requirements of the excavator, the controller provides a fixed current value to the electric proportional relief valve 35 during a certain period of time. The magnitude of the current value depends on the maximum fan 5 speed required for water cooling, air cooling, and hydraulic oil cooling under the working conditions of the excavator at that time. For example: the water cooling of the excavator at this time requires the fan 5 to provide a speed of 700rpm, the air cooling requires the fan 5 to provide a speed of 600rpm, and the hydraulic oil cooling requires the fan 5 to provide a speed of 1000rpm. At this time, the magnitude of the current value selects the current value corresponding to the speed of 1000rpm. The water cooling, air cooling, and hydraulic oil cooling are all provided with temperature sensors to monitor the temperature in real time.

[0051] When the excavator is powered on, the left electromagnet of the electromagnetic reversing valve 31 of the heat dissipation hydraulic system is energized, so that it is in the first working position. At this time, the engine is not started and the pump 1 does not provide hydraulic pressure. When the engine is started, the pump 1 provides hydraulic pressure to drive the hydraulic motor 4 to rotate, and the hydraulic motor 4 drives the fan 5 to rotate to dissipate heat for the excavator.

[0052] In cold weather, when the temperature sensors of water cooling, air cooling and hydraulic oil cooling detect that the temperature is in a low temperature state and the fan 5 is no longer needed to rotate to dissipate heat for the whole excavator, the controller controls the electromagnets on both sides of the electromagnetic reversing valve 31 to lose power, so that it is in the second working position (that is, the valve core is in the middle position), and the hydraulic oil directly returns to the oil tank 2, which reduces energy waste and can improve the performance and fuel economy of the whole vehicle;

[0053] When the excavator needs to perform the back-blowing function, the display screen reversing function is operated. At this time, the electromagnets on both sides of the electromagnetic reversing valve 31 are de-energized, making it in the second working position (that is, the valve core is in the middle position); because the fan 5 is rotating at a high speed during forward rotation, the inertia of the fan 5 is relatively large. At this time, the second throttle valve 33 with the valve core in the middle position is required to increase the return oil back pressure, so that the fan 5 can be completely stopped in a shorter time without hydraulic shock; after the fan 5 is completely stopped, the electromagnet on the right side of the electromagnetic reversing valve 31 is energized, and at this time the electromagnetic proportional relief valve will provide the designed maximum pressure, and the speed of the fan 5 will reach the designed maximum speed for reverse rotation. Blowing operation; after the fan 5 has been back-blowing for a few minutes, the controller will automatically de-energize the electromagnets on both sides of the electromagnetic reversing valve 31, and the valve core will be in the middle position; because the fan 5 is rotating at high speed during reversal, the fan 5 has a large inertia, and at this time, the first throttle valve 32 with the valve core in the middle position needs to increase the return oil back pressure, so that the fan 5 can be completely stopped in a short time, and there will be no hydraulic shock phenomenon; after the fan 5 is completely stopped, the electromagnet on the left side of the electromagnetic reversing valve 31 is energized, and at this time, the electromagnetic proportional overflow valve will provide the corresponding pressure according to the actual situation of the cooling system at that time, and the fan 5 will resume normal cooling operation; at this point, the entire back-blowing function operation is completed. The hydraulic cooling control system provided by the utility model can greatly improve the reliability of the fan 5 and the hydraulic motor 4, and make the operation reversal function more humane; at the same time, in cold weather, it can better improve the performance and fuel economy of the whole vehicle.

[0054] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A heat dissipation hydraulic system, characterized in that: It includes a pump, an oil tank, an electromagnetic proportional valve group, a hydraulic motor and a fan connected to the hydraulic motor. The electromagnetic proportional valve group includes an electromagnetic reversing valve, the electromagnetic reversing valve has a first working position, a second working position and a third working position, and the second working position is provided with a first throttle valve and a second throttle valve; The two oil ports of the hydraulic motor are respectively connected to the electromagnetic reversing valve, and the pump is connected to the oil inlet of the electromagnetic proportional valve group; When the electromagnetic reversing valve is in the first working position, under the action of the pump, the hydraulic motor is supplied with oil in a positive direction, and the fan rotates forward under the positive drive of the hydraulic motor; When the electromagnetic reversing valve is in the second working position, the oil of the hydraulic motor is connected to the oil tank after being throttled by the first throttle valve or the second throttle valve, so that the fan is switched from a moving state to a stationary state; When the electromagnetic reversing valve is in the third working position, under the action of the pump, the hydraulic motor supplies oil in the reverse direction, and the fan is reversed under the reverse drive of the hydraulic motor.

2. A heat dissipation hydraulic system according to claim 1, characterized in that: The solenoid reversing valve is a three-position four-way solenoid proportional reversing valve, and a first working oil port, a second working oil port, a reversing oil inlet port and a reversing oil return port are provided on its valve body. The first working oil port and the second working oil port are respectively connected to the two oil ports of the hydraulic motor, the reversing oil inlet port is connected to the oil inlet port of the solenoid proportional valve group, and the reversing oil return port is connected to the oil tank.

3. A heat dissipation hydraulic system according to claim 2, characterized in that: The neutral position function of the electromagnetic reversing valve is H type.

4. A heat dissipation hydraulic system according to any one of claims 1 to 3, characterized in that: The electromagnetic proportional valve group further includes an electric proportional overflow valve having a first overflow port and a second overflow port. The first overflow port is connected to the oil inlet of the electromagnetic proportional valve group, and the second overflow port is connected to the oil tank.

5. A heat dissipation hydraulic system according to claim 2 or 3, characterized in that: The electromagnetic proportional valve group also includes an oil replenishing one-way valve, which is arranged between the reversing oil return port and the reversing oil inlet port, and conducts one-way from the reversing oil return port to the reversing oil inlet port, and is used to replenish oil when the hydraulic motor is sucked empty.

6. A heat dissipation hydraulic system according to claim 4, characterized in that: The heat dissipation hydraulic system further includes a controller and a display, wherein the display is electrically connected to the controller, the electromagnetic reversing valve is electrically connected to the controller, and the electric proportional relief valve is electrically connected to the controller.

7. An engineering equipment, characterized in that: Comprising a heat dissipation hydraulic system as described in any one of claims 1-6.

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