Independent heat dissipation hydraulic system and engineering machinery equipped with the same

Abstract

The present invention relates to an independent heat dissipation hydraulic system and engineering machinery equipped with the hydraulic system. The independent heat dissipation hydraulic system includes a hydraulic pump and a fan drive oil circuit and a delay control oil circuit connected in parallel. When the main oil circuit and the delay control oil circuit are connected, the oil in the main oil circuit flows through the pilot control oil port to push the valve core of the hydraulically controlled reversing valve to reverse, and at the same time, the oil in the main oil circuit fills the accumulator; when the main oil circuit and the delay control oil circuit are blocked, the accumulator releases the stored oil to act on the pilot control oil port to keep the valve core of the hydraulically controlled reversing valve in a reversing state; when the oil in the accumulator stops being released, the valve core of the hydraulically controlled reversing valve reverses and resets under the action of the spring force. This hydraulic system can avoid pressure shocks caused by rapid switching of the oil circuits, so that the motor reverses and stops smoothly.

Description

Technical Field

[0001] The present invention relates to a hydraulic system, in particular to an independent heat dissipation hydraulic system and engineering machinery provided with the hydraulic system. Background Art

[0002] Large excavators, both domestic and international, utilize high-power engines. While cooling efficiency is high when using direct-drive fans, this can lead to significant energy waste during winter. To conserve fuel, large excavator cooling systems currently utilize independent hydraulic systems. Furthermore, the fans can reverse to remove dust from the radiator surface, preventing it from covering the surface and impacting cooling. High hydraulic oil temperatures can affect the performance of hydraulic components and even cause them to malfunction. Preventing pressure shock and cavitation during operation of the cooling pump and motor, and improving cooling system reliability, are key to ensuring reliable excavator operation and are a key indicator of product competitiveness.

[0003] In the prior art, the independent heat dissipation hydraulic system of the excavator utilizes the forward and reverse rotation of the fan to achieve heat dissipation and clean the dust on the surface of the radiator. When rotating forward, the motor works in the state of oil inlet at port A and oil return at port B to dissipate heat to the radiator. When the electromagnetic reversing valve is energized, the motor works in the state of oil inlet at port B and oil return at port A, driving the fan to reverse. At this time, the function of the fan is to remove dust, lint and other dirt attached to the surface of the radiator.

[0004] However, when the motor's reverse operation needs to be stopped in the above hydraulic system, the solenoid reversing valve loses power and immediately switches to the forward oil circuit state. The motor's operating state suddenly changes from oil return port A to oil inlet port A. The motor continues to rotate under the action of inertia. The closed oil circuit between the hydraulic variable pump and the motor oil inlet immediately generates a high-pressure shock acting on the motor, shortening its lifespan. Furthermore, the motor's return oil returns directly to the tank, resulting in too little back pressure, which can easily cause cavitation in the motor, shortening its lifespan. Summary of the Invention

[0005] In order to overcome the deficiencies in the prior art, the present invention provides an independent heat dissipation hydraulic system, which can avoid pressure shock caused by rapid switching of oil circuits, so that the motor can stop smoothly during reverse rotation.

[0006] The technical solution adopted by the present invention is: an independent heat dissipation hydraulic system, including a hydraulic pump and a fan drive oil circuit and a delay control oil circuit connected in parallel;

[0007] The fan drive oil circuit includes a hydraulically controlled reversing valve and a hydraulic motor connected in sequence to the hydraulic pump, the hydraulically controlled reversing valve is used to control the forward and reverse rotation of the hydraulic motor, and the fan drive oil circuit also includes a relief valve for controlling the pressure of the independent heat dissipation hydraulic system, the outlet of the relief valve is connected to the hydraulic oil tank through a pipeline;

[0008] The delay control oil circuit includes an electromagnetic reversing valve and an accumulator connected in sequence to the hydraulic pump, and the delay control oil circuit also includes a delay valve, the oil inlet of the delay valve is connected to the oil return port of the electromagnetic reversing valve through a pipeline, the oil outlet of the delay valve is connected to the hydraulic oil tank, and the working oil port of the electromagnetic reversing valve is connected to the pilot control oil port of the hydraulically controlled reversing valve and the accumulator through pipelines respectively;

[0009] When the main oil circuit is connected to the delay control oil circuit, the oil in the main oil circuit flows through the pilot control oil port to push the valve core of the hydraulically controlled reversing valve to change direction, and at the same time, the oil in the main oil circuit fills the accumulator;

[0010] When the main oil circuit and the delay control oil circuit are blocked, the accumulator releases stored oil through the delay valve, which controls the rate of oil release from the accumulator. During the oil release process, the accumulator precharge pressure continuously acts on the pilot control port, maintaining the spool of the hydraulically controlled reversing valve in a reversing state. When the accumulator stops releasing oil, the spool of the hydraulically controlled reversing valve reverses and resets under the action of a spring. The accumulator volume and the flow rate parameters of the delay valve are determined based on the duration of the fan shutdown.

[0011] Furthermore, the hydraulically controlled reversing valve is a two-position four-way hydraulically controlled reversing valve or a three-position four-way hydraulically controlled reversing valve.

[0012] Furthermore, the hydraulically controlled reversing valve is a three-position four-way hydraulically controlled reversing valve, and the middle position function of the three-position four-way hydraulically controlled reversing valve is H-type.

[0013] Furthermore, the normal position of the hydraulically controlled reversing valve is the left position or the right position.

[0014] Furthermore, the hydraulic pump is a fixed displacement pump or a variable displacement pump.

[0015] Furthermore, it also includes a first oil-supply check valve and a second oil-supply check valve, the outlet of the relief valve is connected to the two working oil ports of the hydraulically controlled reversing valve through pipelines, and the first oil-supply check valve and the second oil-supply check valve are connected to the pipelines between the outlet of the relief valve and the two working oil ports of the hydraulically controlled reversing valve;

[0016] The oil outlet of the first oil-supply one-way valve is connected to the first oil outlet of the hydraulically controlled reversing valve, and the oil outlet of the second oil-supply one-way valve is connected to the second oil outlet of the hydraulically controlled reversing valve.

[0017] Furthermore, the delay control oil circuit also includes a one-way throttle valve, which is connected to the pipeline between the electromagnetic reversing valve and the accumulator.

[0018] Furthermore, it also includes an oil return back pressure valve, and the oil return pipeline of the hydraulically controlled reversing valve and the oil return pipeline of the overflow valve are merged and then return to the hydraulic oil tank through the oil return back pressure valve.

[0019] The present invention also provides an engineering machine comprising the above-mentioned independent heat dissipation hydraulic system.

[0020] Furthermore, the above-mentioned engineering machinery also includes a hydraulic excavator.

[0021] The beneficial effects produced by the present invention include: 1. The system is provided with a delay valve, a one-way throttle valve and an accumulator, so that the hydraulically controlled reversing valve can reverse quickly when reversing is started, and at the same time, the control pressure of the hydraulically controlled reversing valve can be delayed when reversing is stopped, thereby solving the problem of motor back-drag caused by the sudden switching of the electromagnetic reversing valve to the forward oil circuit due to power failure of the existing solution, reducing the pressure shock of the pump and motor when reversing is stopped, and improving the service life of the pump and motor.

[0022] 2. The system is equipped with an oil return back pressure valve, and the oil replenishment check valve is installed after the hydraulically controlled reversing valve, which increases the oil replenishment pressure while reducing the pressure loss during oil replenishment, solving the motor suction problem caused by the motor stopping process in the existing solution and extending the service life of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the connection structure of an independent heat dissipation hydraulic system provided by an embodiment of the present invention;

[0024] In the figure: 1- hydraulic variable pump; 2- delay valve; 3- overflow valve; 4- electromagnetic reversing valve; 5- one-way throttle valve; 6- accumulator; 7- hydraulically controlled reversing valve; 8- oil supply check valve; 9- oil supply check valve; 10- motor; 11- fan; 12- oil return back pressure valve 13- hydraulic oil tank. DETAILED DESCRIPTION

[0025] The present invention will be further explained in detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that the protection scope of the present invention is not limited to the specific embodiments.

[0026] Figure 1 For a schematic diagram of the connection structure of an independent heat dissipation hydraulic system provided by an embodiment of the present invention, please refer to Figure 1, the oil inlet of the hydraulic variable pump 1 is connected to the hydraulic oil tank 13, and the oil outlet is connected to the oil inlet of the relief valve 3, the oil inlet of the electromagnetic reversing valve 4, and the oil inlet of the hydraulic control reversing valve 7 at the same time; the oil inlet of the relief valve 3 is connected to the hydraulic variable pump 1, and the oil outlet is connected to the oil inlet of the return oil back pressure valve 12; the oil outlet of the return oil back pressure valve 12 is connected to the hydraulic oil tank 13; the oil inlet of the electromagnetic reversing valve 4 is connected to the oil outlet of the hydraulic variable pump 1, and the oil outlet is simultaneously connected to the pilot port of the hydraulic control reversing valve 7 and the oil inlet of the one-way throttle valve 5, and the oil return port of the electromagnetic reversing valve 4 is connected to the oil inlet of the delay valve 2; the oil inlet of the one-way throttle valve 5 is connected to the oil outlet of the electromagnetic reversing valve 4 and the pilot port of the hydraulic control reversing valve, and the oil outlet is connected to the accumulator 6; the oil inlet of the delay valve 2 is connected to the oil return port of the electromagnetic reversing valve 4, and the oil outlet is connected to the hydraulic oil tank 13; the oil inlet of the hydraulic control reversing valve 7 is connected The oil outlet of the hydraulic variable pump 1 is connected, the left oil outlet is connected to the oil port A of the motor 5, the right oil outlet is connected to the oil port B of the motor 5, the pilot port is simultaneously connected to the oil outlet of the solenoid reversing valve 4 and the oil inlet of the one-way throttle valve, the return oil port is simultaneously connected to the oil inlet of the oil replenishment check valve 8, the oil inlet of the oil replenishment check valve 9, the oil outlet of the relief valve 3, and the oil inlet of the return oil back pressure valve 12; the oil inlet of the oil replenishment check valve 8 is connected to the oil inlet of the return oil back pressure valve 12, and the oil outlet is connected to the oil port A of the motor 5; the oil inlet of the oil replenishment check valve 9 is connected to the oil inlet of the return oil back pressure valve 12, and the oil outlet is connected to the oil port B of the motor 5; the oil port A of the motor 5 is simultaneously connected to the left oil outlet of the hydraulically controlled reversing valve and the oil outlet of the oil replenishment check valve 8, the oil port B of the motor 5 is simultaneously connected to the right oil outlet of the hydraulically controlled reversing valve and the oil outlet of the oil replenishment check valve 9, and the shaft end of the motor 5 is mechanically connected to the fan 6.

[0027] The working principle of the present invention is as follows: when the electromagnetic reversing valve 4 is not energized, the hydraulic variable pump 1 outputs hydraulic oil through the hydraulically controlled reversing valve 7 and enters the oil port A of the motor 10, driving the motor 10 and the fan 11 to rotate forward, and the hydraulic oil output from the oil port B of the motor 10 flows back to the hydraulic oil tank 13 through the hydraulically controlled reversing valve 7 and the return oil back pressure valve 12; when the cooling system stops working, the hydraulic variable pump 1 stops running, and the motor 10 and the fan 11 continue to rotate by inertia, and the hydraulic oil output from the oil port B of the motor 10 returns oil through the return oil back pressure valve 4 to generate return oil back pressure. When the oil inlet pressure of the oil port A of the motor 10 is lower than the return oil pressure of the oil port B, the oil is replenished to the oil port A of the motor 10 through the oil replenishment check valve 8 until the motor 10 and the fan 11 stop. When the electromagnetic reversing valve 4 is energized, the hydraulic oil output by the hydraulic variable pump 1 pushes the hydraulic control reversing valve 7 to reverse through the electromagnetic reversing valve 4, and at the same time fills the accumulator 6 through the throttle hole of the one-way throttle valve 5. The hydraulic variable pump 1 enters the oil port B of the motor 10 through the hydraulic control reversing valve 7, driving the motor 10 and the fan 11 to reverse. The hydraulic oil output from the oil port A of the motor 10 flows back to the hydraulic oil tank 13 through the hydraulic control reversing valve 7 and the return oil back pressure valve 12; when the cooling system stops working, the electromagnetic reversing valve 4 When the power is lost and the direction is reversed, the hydraulic oil in the accumulator 6 slowly releases a certain pressure of oil through the one-way valve of the one-way throttle valve 5, the electromagnetic reversing valve 4, and the delay valve 2. This pressure can continue to keep the hydraulic control reversing valve 7 in the reversing state for a period of time, so that the motor 10 and the fan 11 can keep rotating in the same direction by inertia. When the oil inlet pressure of the motor 10 oil port B is lower than the oil return pressure of the oil port A, the oil is replenished to the motor 10 oil port B through the oil replenishment check valve 9 until the motor 10 and the fan 11 stop. Figure 1 .

[0028] The present invention also has the following features: the hydraulic variable pump can be replaced by a combination of a fixed displacement pump and a proportional relief valve, and the reset time of the hydraulically controlled reversing valve can be controlled by changing the pre-charge pressure of the accumulator.

[0029] Without changing the existing control method, this embodiment achieves motor directional control through the combined use of a solenoid-operated reversing valve and a hydraulic-controlled reversing valve. An accumulator, a one-way throttle valve, and a time-delay valve are added to the control oil circuit. By controlling the delayed switching of the hydraulic-controlled reversing valve, pressure shocks caused by rapid oil circuit switching are avoided, allowing the motor to smoothly stop during reverse rotation. Furthermore, the addition of an oil return back-pressure valve and the installation of an oil-replenishing check valve after the hydraulic-controlled valve increase oil-replenishing pressure, reduce pressure loss during replenishment, and prevent cavitation in the motor.

[0030] While the specific embodiments of the present invention have been described in detail above, these are merely exemplary and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, any equivalent changes and modifications made without departing from the spirit and scope of the present invention are intended to be encompassed within the scope of the present invention.

Claims

1. An independent heat dissipation hydraulic system, characterized by: It includes a hydraulic pump and a fan drive oil circuit and a delay control oil circuit connected in parallel with each other; The fan drive oil circuit includes a hydraulically controlled reversing valve and a hydraulic motor connected in sequence to the hydraulic pump, the hydraulically controlled reversing valve is used to control the forward and reverse rotation of the hydraulic motor, and the fan drive oil circuit also includes a relief valve for controlling the pressure of the independent heat dissipation hydraulic system, the outlet of the relief valve is connected to the hydraulic oil tank through a pipeline; The delay control oil circuit includes an electromagnetic reversing valve and an accumulator connected in sequence to the hydraulic pump, the delay control oil circuit also includes a delay valve, the oil inlet of the delay valve is connected to the oil return port of the electromagnetic reversing valve through a pipeline, the oil outlet of the delay valve is connected to the hydraulic oil tank, and the working oil port of the electromagnetic reversing valve is connected to the pilot control oil port of the hydraulically controlled reversing valve and the accumulator through pipelines respectively; the delay control oil circuit also includes a one-way throttle valve, which is connected to the pipeline between the electromagnetic reversing valve and the accumulator; When the main oil circuit is connected to the delay control oil circuit, the oil in the main oil circuit flows through the pilot control oil port to push the valve core of the hydraulically controlled reversing valve to change direction, and at the same time, the oil in the main oil circuit fills the accumulator; When the main oil circuit and the delay control oil circuit are blocked, the accumulator releases the stored oil to act on the pilot control oil port to keep the valve core of the hydraulically controlled reversing valve in a reversing state; when the oil in the accumulator stops being released, the valve core of the hydraulically controlled reversing valve is reversed and reset under the action of the spring force; The hydraulically controlled reversing valve is a two-position four-way hydraulically controlled reversing valve or a three-position four-way hydraulically controlled reversing valve.

2. The independent heat dissipation hydraulic system according to claim 1, characterized in that: The hydraulically controlled reversing valve is a three-position four-way hydraulically controlled reversing valve, and the middle position function of the three-position four-way hydraulically controlled reversing valve is H-type.

3. The independent heat dissipation hydraulic system according to claim 1, characterized in that: The hydraulic pump is a fixed displacement pump or a variable displacement pump.

4. The independent heat dissipation hydraulic system according to claim 1, characterized in that: It also includes a first oil-supply check valve and a second oil-supply check valve, the outlet of the relief valve is connected to the two working oil ports of the hydraulically controlled reversing valve through pipelines, and the first oil-supply check valve and the second oil-supply check valve are connected to the pipelines between the outlet of the relief valve and the two working oil ports of the hydraulically controlled reversing valve; The oil outlet of the first oil-supply one-way valve is connected to the first oil outlet of the hydraulically controlled reversing valve, and the oil outlet of the second oil-supply one-way valve is connected to the second oil outlet of the hydraulically controlled reversing valve.

5. The independent heat dissipation hydraulic system according to claim 1, characterized in that: It also includes an oil return back pressure valve. The oil return pipeline of the hydraulically controlled reversing valve and the oil return pipeline of the overflow valve merge and then return to the hydraulic oil tank through the oil return back pressure valve.

6. An engineering machine, characterized in that: It comprises the independent heat dissipation hydraulic system as described in any one of claims 1-5.

7. The engineering machine according to claim 6, wherein: The engineering machine includes a hydraulic excavator.

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