Hydraulic cooler control valve group, hydraulic system and control method

Abstract

The invention discloses a hydraulic cooler control valve bank, a hydraulic system and a control method.The hydraulic cooler control valve bank comprises a first electromagnetic valve, a second electromagnetic valve, an overflow valve, a first one-way valve, a control valve bank port P, a control valve bank port T, a control valve bank port A1, a control valve bank port A and a control valve bank port B; a main oil inlet P of the first electromagnetic valve is communicated with a port P of the control valve group, a control oil port A of the first electromagnetic valve is communicated with a port A1 of the control valve group, a control oil port B of the first electromagnetic valve is divided into two paths, one path is communicated with an oil inlet of the overflow valve, and the other path is communicated with a main oil inlet P of the second electromagnetic valve; a control oil port A of the second electromagnetic valve is communicated with a port A of the control valve set, a control oil port B of the second electromagnetic valve is connected with a port B of the control valve set, the inlet end of the first one-way valve is communicated with the port B of the control valve set, and the outlet end of the first one-way valve is communicated with the port A of the control valve set. And a control oil port B of the second electromagnetic valve, a main oil return port T of the second electromagnetic valve, an oil outlet of the overflow valve and a port B of the control valve group are respectively communicated with a port T of the control valve group. The intelligent cooling system is good in intelligent degree, cooling effect and safety performance.

Description

Technical Field

[0001] The invention relates to the technical field of engineering machinery, and in particular discloses a hydraulic cooler control valve group, a hydraulic system and a control method. Background Art

[0002] Engineering machinery, such as lifting machinery, is generally driven by hydraulics. Energy loss occurs in the process of energy conversion and transmission in the hydraulic system. As the medium for energy transmission, continuous operation of hydraulic oil will increase the temperature of the hydraulic oil. In order to ensure that the engineering machinery works normally for a long time without damaging the hydraulic components, hydraulic coolers are used in hydraulic systems to exchange heat between the high-temperature hydraulic oil and the forced-flowing cold air to control the oil temperature within a reasonable range. However, existing hydraulic coolers have poor cooling effect and safety performance.

[0003] Therefore, the existing hydraulic coolers have poor cooling effect and safety performance, which is a technical problem that needs to be solved urgently. Summary of the invention

[0004] The present invention provides a hydraulic cooler control valve group, a hydraulic system and a control method, aiming to solve at least one of the above-mentioned defects of the existing hydraulic cooler.

[0005] One aspect of the present invention relates to a hydraulic cooler control valve group, comprising a first solenoid valve, a second solenoid valve, a relief valve, a first non-return valve, a control valve group P port, a control valve group T port, a control valve group A1 port, a control valve group A port and a control valve group B port, wherein a main oil inlet P of the first solenoid valve is connected to the control valve group P port, a control oil port A of the first solenoid valve is connected to the control valve group A1 port, a control oil port B of the first solenoid valve is divided into two paths, one path is connected to the oil inlet of the relief valve, and the other path is connected to the main oil inlet P of the second solenoid valve; the control oil port A of the second solenoid valve is connected to the control valve group A port, the control oil port B of the second solenoid valve is connected to the control valve group B port, the inlet end of the first non-return valve is connected to the control valve group B port, and the outlet end of the first non-return valve is connected to the control valve group A port; the control oil port B of the second solenoid valve, the main oil return port T of the second solenoid valve, the oil outlet of the relief valve, and the control valve group B port are respectively connected to the control valve group T port.

[0006] Furthermore, the first solenoid valve is a two-position three-way solenoid valve.

[0007] Furthermore, the second solenoid valve is a three-position four-way solenoid valve.

[0008] Another aspect of the present invention relates to a hydraulic cooler control system, comprising the above-mentioned hydraulic cooler control valve group, cooler assembly and hydraulic pump, wherein the control valve group A port is connected to the hydraulic motor A2 port of the cooler assembly, the control valve group B port is connected to the hydraulic motor B2 port of the cooler assembly, and the hydraulic pump is connected to the control valve group P port.

[0009] Furthermore, the cooler assembly includes a temperature sensor, a cooler, a hydraulic motor, a hydraulic motor A2 port, a hydraulic motor B2 port, a cooler T2 port and a cooler T3 port. The temperature sensor is connected to the cooler, the cooler is respectively connected to the cooler T2 port and the cooler T3 port, and the hydraulic motor is respectively connected to the hydraulic motor A2 port and the hydraulic motor B2 port.

[0010] Furthermore, the hydraulic cooler control system further comprises a second one-way valve, an inlet end of the second one-way valve is connected to the cooler T2 port, and an outlet end of the second one-way valve is connected to the cooler T3 port.

[0011] Furthermore, the hydraulic cooler control system also includes a hydraulic oil tank, the oil tank suction port X of the hydraulic oil tank is connected to the hydraulic pump; the oil tank return port T1 of the hydraulic oil tank is connected to the cooler T3 port; the control valve group T port is connected to the cooler T2 port.

[0012] Furthermore, the first one-way valve is connected to the cooler T2 port through the hydraulic system return oil circuit, and is used to replenish oil to the hydraulic motor A2 port to prevent the hydraulic motor from being instantly sucked out when the hydraulic cooler control system is turned on.

[0013] Furthermore, a second one-way valve is connected in parallel with the cooler assembly to prevent the return oil pressure from exceeding the working pressure of the cooler.

[0014] Another aspect of the present invention relates to a hydraulic cooler control method, which is applied to the above-mentioned hydraulic cooler control system. The hydraulic cooler control method comprises the following steps:

[0015] When other oil circuits of the hydraulic system are not working and the lifting machinery is in motion, the temperature sensor installed on the cooler assembly detects that the temperature of the hydraulic oil entering the cooler reaches the set value T℃, and the hydraulic cooler control system is controlled to start;

[0016] The hydraulic pump sucks oil from the oil tank suction port X, pumps out high-pressure oil and flows into the control valve group P port of the hydraulic cooler control valve group. The first solenoid Y1 of the first solenoid valve in the hydraulic cooler control valve group is energized, and the second solenoid Y2 on the second solenoid valve is energized at the same time. The high-pressure oil enters the main oil inlet P of the second solenoid valve from the control valve group P port through the main oil inlet P of the first solenoid valve, and flows into the hydraulic motor A2 port of the cooler from the control valve group A port of the hydraulic cooler control valve group. The hydraulic motor drives the fan of the cooler to rotate, and cools the hydraulic oil entering the cooler from the hydraulic system return oil circuit. At the same time, the return oil of the hydraulic motor flows from the hydraulic motor B2 port through the control valve group B port, and then flows to the control valve group T port, and then flows into the cooler T2 oil inlet port. After being cooled by the cooler, it enters the oil tank return port T1 port of the hydraulic oil tank through the cooler T3 port.

[0017] The beneficial effects achieved by the present invention are:

[0018] The present invention provides a hydraulic cooler control valve group, a hydraulic system and a control method. The hydraulic cooler control valve group adopts a first solenoid valve, a second solenoid valve, a relief valve, a first check valve, a control valve group P port, a control valve group T port, a control valve group A1 port, a control valve group A port and a control valve group B port, wherein the main oil inlet P of the first solenoid valve is connected to the control valve group P port, the control oil port A of the first solenoid valve is connected to the control valve group A1 port, and the control oil port B of the first solenoid valve is divided into two paths, one of which is connected to the relief valve. The oil inlet of the first check valve is connected to the oil inlet of the second solenoid valve, and the other is connected to the main oil inlet P of the second solenoid valve; the control oil port A of the second solenoid valve is connected to the A port of the control valve group, the control oil port B of the second solenoid valve is connected to the B port of the control valve group, the inlet end of the first check valve is connected to the B port of the control valve group, and the outlet end of the first check valve is connected to the A port of the control valve group; the control oil port B of the second solenoid valve, the main oil return port T of the second solenoid valve, the oil outlet of the overflow valve, and the B port of the control valve group are respectively connected to the T port of the control valve group. The hydraulic cooler control valve group, hydraulic system and control method provided by the present invention have the following beneficial effects:

[0019] 1. Provide a new control valve group for a cooler with good intelligence, cooling effect and safety performance.

[0020] 2. The control valve group is equipped with an oil replenishment check valve to replenish oil to the hydraulic motor in time to prevent the motor from sucking oil.

[0021] 3. A temperature sensor is set in the cooler to detect the oil temperature in the system in real time, and the detected oil temperature is more accurate.

[0022] 4. The hydraulic cooler control system shares a hydraulic pump with other actions, saving costs and installation space. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a principle schematic diagram of the hydraulic cooler control valve group of the present invention;

[0024] Figure 2 It is a principle schematic diagram of the hydraulic cooler control system of the present invention;

[0025] Figure 3 It is a schematic diagram of the principle of the cooler assembly of the present invention.

[0026] Description of Figure Numbers:

[0027] 11. First solenoid valve; 12. Second solenoid valve; 13. Overflow valve; 14. First one-way valve; 10. Hydraulic cooler control valve group; 20. Cooler assembly; 30. Hydraulic pump; 40. Second one-way valve; 50. Hydraulic oil tank; 21. Temperature sensor; 22. Cooler; 23. Hydraulic motor. DETAILED DESCRIPTION

[0028] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0029] like Figures 1 to 3 As shown, the first embodiment of the present invention proposes a hydraulic cooler control valve group, including a first solenoid valve 11, a second solenoid valve 12, a relief valve 13, a first check valve 14, a control valve group P port, a control valve group T port, a control valve group A1 port, a control valve group A port and a control valve group B port, wherein the main oil inlet P of the first solenoid valve 11 is connected to the control valve group P port, the control oil port A of the first solenoid valve 11 is connected to the control valve group A1 port, and the control oil port B of the first solenoid valve 11 is divided into two paths, one of which is connected to the oil inlet of the relief valve 13. The first solenoid valve 11 is connected to the main oil inlet P of the second solenoid valve 12; the control oil port A of the second solenoid valve 12 is connected to the A port of the control valve group, the control oil port B of the second solenoid valve 12 is connected to the B port of the control valve group, the inlet end of the first check valve 14 is connected to the B port of the control valve group, and the outlet end of the first check valve 14 is connected to the A port of the control valve group; the control oil port B of the second solenoid valve 12, the main oil return port T of the second solenoid valve 12, the oil outlet of the overflow valve 13, and the B port of the control valve group are respectively connected to the T port of the control valve group. In this embodiment, the first solenoid valve 11 adopts a two-position three-way solenoid valve. The second solenoid valve 12 adopts a three-position four-way solenoid valve. The hydraulic cooler control valve group provided in this embodiment has good intelligence, cooling effect and safety performance; the control valve group is provided with a first check valve 14 to replenish oil to the hydraulic motor in time to prevent the motor from sucking air.

[0030] Further, see Figures 1 to 3The hydraulic cooler control system involved in this embodiment includes the above-mentioned hydraulic cooler control valve group 10, cooler assembly 20 and hydraulic pump 30, wherein the control valve group A port is connected to the hydraulic motor A2 port of the cooler assembly 20, the control valve group B port is connected to the hydraulic motor B2 port of the cooler assembly 20, and the hydraulic pump 30 is connected to the control valve group P port. Specifically, the cooler assembly 20 includes a temperature sensor 21, a cooler 22, a hydraulic motor 23, a hydraulic motor A2 port, a hydraulic motor B2 port, a cooler T2 port and a cooler T3 port, the temperature sensor 21 is connected to the cooler 22, the cooler 22 is connected to the cooler T2 port and the cooler T3 port respectively, and the hydraulic motor 23 is connected to the hydraulic motor A2 port and the hydraulic motor B2 port respectively. In the hydraulic cooler control system involved in this embodiment, a temperature sensor is set in the cooler assembly 20 to detect the oil temperature in the system in real time, and the detected oil temperature is more accurate.

[0031] Preferably, see Figures 1 to 3 The hydraulic cooler control system provided in this embodiment further includes a second one-way valve 40, the inlet end of the second one-way valve 40 is connected to the cooler T2 port, and the outlet end of the second one-way valve 40 is connected to the cooler T3 port. The hydraulic cooler control system also includes a hydraulic oil tank 50, the oil tank suction port X of the hydraulic oil tank 50 is connected to the hydraulic pump 30; the oil tank return port T1 of the hydraulic oil tank 50 is connected to the cooler T3 port; the control valve group T port is connected to the cooler T2 port. The first one-way valve 14 is connected to the cooler T2 port through the hydraulic system return oil circuit, and is used to replenish oil to the hydraulic motor A2 port to prevent the hydraulic motor 23 from being instantly sucked out when the hydraulic cooler control system is turned on. The second one-way valve 40 is connected in parallel with the cooler assembly 20 to prevent the return oil pressure from exceeding the working pressure of the cooler. In the hydraulic cooler control system provided in this embodiment, the second one-way valve 40 is connected in parallel with the cooler assembly 20 in the cooling system to prevent the return oil pressure from exceeding the working pressure of the cooler, thereby playing a protective role.

[0032] The present invention relates to a hydraulic cooler control method, which is applied to the above-mentioned hydraulic cooler control system. The hydraulic cooler control method comprises the following steps:

[0033] Step S100, when other oil circuits of the hydraulic system are not working and the lifting machinery is in motion, the temperature sensor 21 installed on the cooler assembly 20 detects that the temperature of the hydraulic oil entering the cooler reaches the set value T°C, and controls the hydraulic cooler control system to start.

[0034] When other oil circuits of the hydraulic system are not working and the lifting machinery is in motion, the temperature sensor installed on the cooler detects that the temperature of the hydraulic oil entering the cooler reaches the set value T℃, and the cooling system needs to be turned on.

[0035] Step S200, the hydraulic pump 30 sucks oil from the oil tank suction port X, pumps out high-pressure oil and flows into the control valve group P port of the hydraulic cooler control valve group 10, the first electromagnet Y1 of the first solenoid valve 11 in the hydraulic cooler control valve group 10 is energized, and the second electromagnet Y2 on the second solenoid valve 12 is energized at the same time, and the high-pressure oil enters the main oil inlet P of the second solenoid valve 12 from the control valve group P port through the main oil inlet P of the first solenoid valve 11, and flows into the hydraulic motor A2 port of the cooler from the control valve group A port of the hydraulic cooler control valve group 10. The hydraulic motor 23 drives the fan of the cooler 22 to rotate, and cools the hydraulic oil entering the cooler from the hydraulic system return oil circuit. At the same time, the return oil of the hydraulic motor 23 flows from the hydraulic motor B2 port through the control valve group B port, and then flows to the control valve group T port, and then flows into the oil inlet port T2 of the cooler. After being cooled by the cooler, it enters the oil tank return port T1 port of the hydraulic oil tank 50 through the cooler T3 port.

[0036] The hydraulic pump 30 takes power from the engine power take-off port or is driven by an electric motor. The hydraulic pump 30 draws oil from the oil tank suction port X, pumps out high-pressure oil and flows into the control valve group P port. The first electromagnet Y1 and the second electromagnet Y2 in the hydraulic cooler control valve group 10 are energized at the same time. The high-pressure oil passes through the left position of the first solenoid valve 11 from the control valve group P port, enters the left position of the second solenoid valve 12, and flows into the hydraulic motor A2 port of the cooler from the control valve group A port. The hydraulic motor 23 drives the fan of the cooler 22 to rotate, and cools the hydraulic oil entering the cooler from the hydraulic system return oil circuit. At the same time, the return oil of the hydraulic motor 23 flows from the hydraulic motor B2 port through the control valve group B port, the left position of the second solenoid valve 12, and then flows to the control valve group T port, flows into the cooler T2 port, and after being cooled by the cooler, enters the oil tank return port T1 port through the cooler T3 port.

[0037] like Figures 1 to 3 As shown, the hydraulic cooler control valve group, hydraulic system and control method provided in this embodiment have the following working principles:

[0038] 1. The hydraulic pump 30 takes power from the engine power take-off port or is driven by an electric motor. The hydraulic pump 30 sucks oil from the oil tank suction port X, and the pumped high-pressure oil flows into the control valve group P port. When the first electromagnet Y1 on the first solenoid valve 11 is not energized, the high-pressure oil enters other action oil circuits of the hydraulic system.

[0039] 2. When other oil circuits of the hydraulic system are not working and the lifting machinery is in motion, the temperature sensor installed on the cooler detects that the temperature of the hydraulic oil entering the cooler reaches the set value T℃, and the cooling system needs to be turned on. At this time, the hydraulic pump 30 takes power from the engine power take-off port or is driven by an electric motor. The hydraulic pump 30 sucks oil from the oil tank suction port X, pumps out high-pressure oil and flows into the control valve group P port. The first electromagnet Y1 and the second electromagnet Y2 in the hydraulic cooler control valve group 10 are energized at the same time. The high-pressure oil passes through the left position of the first solenoid valve 11 from the control valve group P port, enters the left position of the second solenoid valve 12, and flows into the hydraulic motor A2 port of the cooler from the control valve group A port. The hydraulic motor 23 drives the fan of the cooler 22 to rotate, and cools the hydraulic oil entering the cooler from the hydraulic system return oil circuit. At the same time, the return oil of the hydraulic motor 23 flows from the hydraulic motor B2 port through the control valve group B port, the left position of the second solenoid valve 12, and then flows to the control valve group T port, flows into the cooler T2 oil inlet, and after being cooled by the cooler, enters the tank return oil port T1 port through the cooler T3 port.

[0040] 3. The hydraulic cooler control valve group 10 is also provided with an overflow valve 13 to prevent the cooling system pressure from exceeding the allowable working pressure of the hydraulic motor.

[0041] 4. The hydraulic cooler control valve group 10 is also provided with a first non-return valve 14 to prevent the hydraulic motor 23 from being sucked into the air when the cooling system is turned on, and to replenish oil from the system oil return line to the hydraulic motor A2 port through the first non-return valve 14.

[0042] 5. In the cooling system, the second one-way valve 40 is connected in parallel with the cooler assembly 20 to prevent the return oil pressure from exceeding the working pressure of the cooler, thereby playing a protective role.

[0043] 6. Arranging the temperature sensor 21 in the cooler is simpler than arranging the temperature sensor in the oil tank in a conventional manner, and the temperature measurement is more accurate.

[0044] Compared with the prior art, the hydraulic cooler control valve group, hydraulic system and control method provided in this embodiment include a first solenoid valve, a second solenoid valve, a relief valve, a first non-return valve, a control valve group P port, a control valve group T port, a control valve group A1 port, a control valve group A port and a control valve group B port, wherein the main oil inlet P of the first solenoid valve is connected to the control valve group P port, the control oil port A of the first solenoid valve is connected to the control valve group A1 port, and the control oil port B of the first solenoid valve is divided into two paths, One path is connected to the oil inlet of the overflow valve, and the other path is connected to the main oil inlet P of the second solenoid valve; the control oil port A of the second solenoid valve is connected to the A port of the control valve group, the control oil port B of the second solenoid valve is connected to the B port of the control valve group, the inlet end of the first check valve is connected to the B port of the control valve group, and the outlet end of the first check valve is connected to the A port of the control valve group; the control oil port B of the second solenoid valve, the main oil return port T of the second solenoid valve, the oil outlet of the overflow valve, and the B port of the control valve group are respectively connected to the T port of the control valve group. The beneficial effects achieved by the hydraulic cooler control valve group, hydraulic system and control method provided in this embodiment are specifically as follows:

[0045] 1. Provide a new control valve group for a cooler with good intelligence, cooling effect and safety performance.

[0046] 2. The control valve group is equipped with an oil replenishment check valve to replenish oil to the hydraulic motor in time to prevent the motor from sucking oil.

[0047] 3. A temperature sensor is set in the cooler to detect the oil temperature in the system in real time, and the detected oil temperature is more accurate.

[0048] 4. The hydraulic cooler control system shares a hydraulic pump with other actions, saving costs and installation space.

[0049] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A hydraulic cooler control valve group, characterized in that: The invention comprises a first solenoid valve (11), a second solenoid valve (12), a relief valve (13), a first non-return valve (14), a control valve group P port, a control valve group T port, a control valve group A1 port, a control valve group A port and a control valve group B port, wherein a main oil inlet P of the first solenoid valve (11) is connected to the control valve group P port, a control oil port A of the first solenoid valve (11) is connected to the control valve group A1 port, and a control oil port B of the first solenoid valve (11) is divided into two paths, one of which is connected to the oil inlet of the relief valve (13) and the other is connected to the oil outlet of the second solenoid valve (12). The main oil inlet P is connected; the control oil port A of the second solenoid valve (12) is connected to the A port of the control valve group, the control oil port B of the second solenoid valve (12) is connected to the B port of the control valve group, the inlet end of the first check valve (14) is connected to the B port of the control valve group, and the outlet end of the first check valve (14) is connected to the A port of the control valve group; the control oil port B of the second solenoid valve (12), the main oil return port T of the second solenoid valve (12), the oil outlet of the overflow valve (13), and the B port of the control valve group are respectively connected to the T port of the control valve group.

2. The hydraulic cooler control valve assembly according to claim 1, characterized in that: The first solenoid valve (11) is a two-position three-way solenoid valve.

3. The hydraulic cooler control valve assembly according to claim 1, characterized in that: The second solenoid valve (12) is a three-position four-way solenoid valve.

4. A hydraulic cooler control system, characterized in that: It comprises a hydraulic cooler control valve group (10), a cooler assembly (20) and a hydraulic pump (30) as described in any one of claims 1 to 3, wherein the A port of the control valve group is connected to the A2 port of the hydraulic motor of the cooler assembly (20), the B port of the control valve group is connected to the B2 port of the hydraulic motor of the cooler assembly (20), and the hydraulic pump (30) is connected to the P port of the control valve group.

5. The hydraulic cooler control system according to claim 4, characterized in that: The cooler assembly (20) comprises a temperature sensor (21), a cooler (22), a hydraulic motor (23), a hydraulic motor A2 port, a hydraulic motor B2 port, a cooler T2 port and a cooler T3 port, wherein the temperature sensor (21) is connected to the cooler (22), the cooler (22) is respectively connected to the cooler T2 port and the cooler T3 port, and the hydraulic motor (23) is respectively connected to the hydraulic motor A2 port and the hydraulic motor B2 port.

6. The hydraulic cooler control system according to claim 5, characterized in that: The hydraulic cooler control system further comprises a second one-way valve (40), the inlet end of the second one-way valve (40) being connected to the cooler T2 port, and the outlet end of the second one-way valve (40) being connected to the cooler T3 port.

7. The hydraulic cooler control system according to claim 6, characterized in that: The hydraulic cooler control system further comprises a hydraulic oil tank (50), an oil tank suction port X of the hydraulic oil tank (50) being connected to the hydraulic pump (30); an oil tank return port T1 of the hydraulic oil tank (50) being connected to a port T3 of the cooler; and a port T of the control valve group being connected to a port T2 of the cooler.

8. The hydraulic cooler control system according to claim 7, characterized in that: The first one-way valve (14) is connected to the cooler T2 port through the hydraulic system oil return line and is used to replenish oil to the hydraulic motor A2 port to prevent the hydraulic motor (23) from being instantly sucked out when the hydraulic cooler control system is turned on.

9. The hydraulic cooler control system according to claim 8, characterized in that: The second one-way valve (40) is connected in parallel with the cooler assembly (20) and is used to prevent the return oil pressure from exceeding the working pressure of the cooler.

10. A hydraulic cooler control method, applied to the hydraulic cooler control system according to any one of claims 4 to 9, characterized in that: The hydraulic cooler control method comprises the following steps: When other oil circuits of the hydraulic system are not working and the lifting machine is in motion, the temperature sensor (21) installed on the cooler assembly (20) detects that the temperature of the hydraulic oil entering the cooler reaches the set value T°C, and controls the hydraulic cooler control system to start; The hydraulic pump (30) sucks oil from the oil tank suction port X, pumps out high-pressure oil and flows into the control valve group P port of the hydraulic cooler control valve group (10), the first electromagnet Y1 of the first solenoid valve (11) in the hydraulic cooler control valve group (10) is energized, and the second electromagnet Y2 on the second solenoid valve (12) is energized at the same time, and the high-pressure oil enters the main oil inlet P of the second solenoid valve (12) from the control valve group P port through the main oil inlet P of the first solenoid valve (11), and flows out from the hydraulic cooler control valve group The hydraulic oil of the control valve group A port of the group (10) flows into the hydraulic motor A2 port of the cooler, and the hydraulic motor (23) drives the fan of the cooler (22) to rotate, cooling the hydraulic oil entering the cooler from the hydraulic system return oil circuit. At the same time, the return oil of the hydraulic motor (23) flows from the hydraulic motor B2 port through the control valve group B port, and then flows to the control valve group T port, and then flows into the cooler T2 port oil inlet port, and after being cooled by the cooler, enters the oil tank return port T1 port of the hydraulic oil tank (50) through the cooler T3 port.

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