A method of providing supplemental lubrication to a directed lubrication system using an oil cooling system

Abstract

The application discloses a method for providing supplementary lubrication for a directional lubrication system by using an oil cooling system, which comprises the following steps: setting a communication pipeline between the front section of an oil return pipeline of a cooling oil channel of the oil cooling system and an oil delivery pipeline of a directional oil channel of the directional lubrication system; when the directional lubrication system cannot supply lubricating oil to each directional lubrication component in time and in sufficient amount, delivering lubricating oil from the oil cooling system to the oil delivery pipeline of the directional lubrication system through the communication pipeline; and closing the communication pipeline when the directional lubrication system can supply oil normally. The method has the advantages that when the directional lubrication system cannot supply oil to the directional lubrication component in time and in sufficient amount, the oil cooling system which is originally independent of the directional lubrication system can temporarily replace the directional lubrication system to supply the required lubricating oil to the directional lubrication component in time, so that dry grinding of related components which have started to rotate due to lack of oil is avoided; the cooling effect of the oil cooling system on the gearbox is not affected at all; and the combination and separation of the functions of the two systems can be automatically switched.

Description

Technical Field

[0001] This invention relates to a method for providing supplemental lubrication to a directional lubrication system using an oil cooling system, belonging to the field of gearbox lubrication technology. Background Technology

[0002] In the mining truck electric drive project, to solve the lubrication and cooling problems of the electric drive gearbox, our solution was to use a mechanical pump to provide targeted lubrication for components requiring directional lubrication. These components are bearings, gears, synchronizers, etc., which are not easily covered by splashed lubricating oil (splashed by the large gear submerged in lubricating oil at the bottom of the gearbox during high-speed rotation). An electric oil pump then draws oil from the bottom of the mining truck electric drive gearbox cavity. The pumped lubricating oil passes through oil holes designed in the housing into a heat exchanger for cooling, and is then returned to the gearbox cavity to cool the gearbox. The mechanical pump is used to lubricate specific components in specific areas, while the electric oil pump and heat exchanger are used to cool the lubricating oil in the internal cavity; lubrication and cooling are originally two independent systems.

[0003] Mechanical pumps have the advantage of high driving torque and are less prone to jamming. However, on the one hand, the drive shaft can only rotate when the wheels and axles inside the gearbox are running. The speed at which the drive shaft rotates directly affects the displacement of the mechanical pump, especially during startup, when the shaft speed driving the mechanical pump is low and the displacement is small, posing a risk of insufficient lubrication for components requiring targeted lubrication. On the other hand, it takes time for the lubricating oil to reach the various components requiring targeted lubrication through the oil passages, and before the lubricating oil reaches these components, there is also a risk of dry friction and poor lubrication. Summary of the Invention

[0004] The technical problem to be solved by this invention is: how to use an oil cooling system to supplement oil supply when the directional lubrication system does not supply oil to the components requiring directional lubrication in a timely or sufficient manner.

[0005] To address the above problems, the technical solution proposed by this invention is as follows:

[0006] A method for providing supplemental lubrication to a directional lubrication system using an oil cooling system involves setting up a connecting pipe between the return oil pipe of the cooling oil passage of the oil cooling system and the oil supply pipe of the directional oil passage of the directional lubrication system. When the directional lubrication system is unable to supply lubricating oil to each directional lubrication component in a timely and sufficient manner, the oil cooling system supplies lubricating oil to the oil supply pipe of the directional lubrication system through the connecting pipe. The connecting pipe is closed when the directional lubrication system can supply oil normally.

[0007] When lubricating oil is supplied to the directional lubrication system's oil supply line through the connecting line at the front end of the return oil line of the cooling oil passage, the rear end of the return oil line is closed. When the connecting line is closed, the rear end of the return oil line of the oil cooling system is opened.

[0008] The measures taken to achieve the alternating closure and opening of the connecting pipeline and the return oil pipeline include setting up a control mechanism between the oil cooling system and the directional lubrication system.

[0009] The measures taken also include setting the oil pressure of the cooling oil return line to be lower than the oil pressure of the directional oil supply line under normal operating conditions, and setting the oil pressure of the return line to be higher than the oil pressure of the supply line under abnormal operating conditions when the mechanical pump speed of the directional lubrication system is low.

[0010] The control mechanism includes a check valve on the connecting pipeline that allows flow only to the oil supply pipeline and is controlled by the pressure difference between the upper and lower pressures; and a pressure control device between the downstream section of the return oil pipeline and the oil supply pipeline for opening and closing the downstream section of the return oil pipeline. When the oil pressure in the oil supply pipeline is lower than the oil pressure in the return oil pipeline, the check valve automatically opens the connecting pipeline, and the pressure control device automatically closes the downstream section of the return oil pipeline of the oil cooling system. When the oil supply pipeline has the oil pressure under normal operating conditions, the check valve automatically closes the connecting pipeline, and the pressure control device automatically opens the downstream section of the return oil pipeline.

[0011] The pressure control device includes a cylinder liner with a cylinder cavity. A piston valve is provided in the cylinder cavity, dividing the cylinder cavity into an upper cylinder cavity and a lower cylinder cavity. The upper cylinder cavity is connected to the oil supply pipeline. A compression spring pre-compressed by the piston valve is provided in the lower cylinder cavity. A valve hole that passes through the piston valve is provided on the piston valve. An oil inlet hole that connects to the front section of the return oil pipeline and an oil outlet hole that connects to the rear section of the return oil pipeline are respectively provided on the left and right cylinder walls of the cylinder cavity. When the piston valve is pushed up by the compression spring so that the valve hole is higher than the oil inlet hole and oil outlet hole on both sides, the rear section of the return oil pipeline is closed. When the piston valve hole is at the same height as the oil inlet hole and oil outlet hole on both sides, the rear section of the return oil pipeline is opened.

[0012] The piston valve is positioned at the upper limit, causing it to pre-compress the spring. When the oil pressure in the delivery line is lower than that in the return line, the oil pressure in the upper cylinder chamber is insufficient to overcome the pre-compression force of the spring, preventing the piston valve from moving downward and keeping the latter part of the return line closed. The piston valve is then positioned at the lower limit. When the oil pressure in the delivery line is higher than that in the return line, the oil pressure in the upper cylinder chamber is sufficient to overcome the pre-compression force of the spring, causing the piston valve to move downward and stop at the lower limit. This ensures that the piston valve orifice is level with the inlet and outlet ports on both sides, allowing the latter part of the return line of the oil cooling system to open.

[0013] The upper limit of the piston valve is achieved by setting an upper limit post at the top of the piston valve that can abut against the top wall of the upper cylinder chamber, and the lower limit of the piston valve is achieved by setting a lower limit post at the bottom of the lower cylinder chamber that can abut against the bottom of the piston valve.

[0014] The control mechanism includes a control system, a solenoid valve 1 on the connecting pipeline, a solenoid valve 2 on the return oil pipeline, and an oil pressure sensor 1 and an oil pressure sensor 2 on the directional oil passage and the cooling oil passage, respectively. The control system controls solenoid valve 1 to open or close the connecting pipeline and controls solenoid valve 2 to open or close the return oil pipeline.

[0015] The above method, when applied to the initial stage of mining card startup, includes the following steps:

[0016] S1. Turn on the electronic oil pump of the oil cooling system. The lubricating oil pumped out by the electronic oil pump first enters the oil delivery pipeline of the directional oil passage of the directional lubrication system through the connecting pipeline, and then reaches each directional lubrication component in a timely and sufficient manner along the oil delivery pipeline. During this process, the latter part of the oil return pipeline of the oil cooling system is closed.

[0017] S2. Start the mining truck. The wheel shaft in the gearbox rotates. The mechanical pump of the directional lubrication system starts synchronously. The speed is not high enough to make the oil pressure in the oil delivery line greater than the oil pressure in the return line. The directional lubrication components still rely on the lubricating oil pumped out by the electronic oil pump for lubrication.

[0018] S3. When the gearbox shafts reach operating conditions, the mechanical pump speed reaches a point where the oil pressure in the delivery line is greater than the oil pressure in the return line. The check valve closes the connecting line, the pressure control device opens the latter part of the return line, and the directional lubrication system and the oil cooling system each perform their respective functions. Beneficial effects

[0019] 1. When the directional lubrication system does not supply oil to the parts that require directional lubrication in a timely and sufficient manner, the oil cooling system, which is originally independent of the directional lubrication system, can be used to temporarily replace the directional lubrication system to provide the required lubricating oil to the parts that require directional lubrication in a timely manner, so as to avoid dry friction of the relevant parts that have already started to rotate due to lack of oil or insufficient oil.

[0020] 2. It does not affect the cooling effect of the oil cooling system on the transmission at all;

[0021] 3. The directional lubrication system and oil cooling system can be automatically switched between combined and separated;

[0022] 4. Simple structure. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing the layout of some external components of the end-of-line oil cooling system and directional lubrication system of the gearbox described in Embodiment 1;

[0024] Figure 2 This is a three-dimensional structural diagram of the main components of the gearbox oil cooling system and directional lubrication system described in Embodiment 1;

[0025] Figure 3 This is a three-dimensional schematic diagram of the flow channels of the transmission oil cooling system and directional lubrication system described in Embodiment 1. The main branches of the oil delivery pipeline are cut out in the diagram.

[0026] Figure 4 The diagram shows a simplified schematic of the flow channel control structure of the transmission oil cooling system and the directional lubrication system described in Example 1. The diagram shows the oil cooling system replenishing lubricating oil to the directional lubrication system, and arrow A indicates the flow direction of the lubricating oil supplied from the oil cooling system to the directional lubrication system at the bottom of the transmission.

[0027] Figure 5 for Figure 4 A partial schematic diagram;

[0028] Figure 6 The diagram shows a simplified schematic of the flow channel control structure of the transmission oil cooling system and the directional lubrication system described in Embodiment 1. The diagram shows that the oil cooling system and the directional lubrication system are functionally separated and work independently. Arrow A indicates that the lubricating oil at the bottom of the transmission is cooled by the oil cooling system and flows directly back to the bottom of the transmission. Arrow B indicates that the lubricating oil at the bottom of the transmission is delivered by the directional lubrication system to the components that require directional lubrication.

[0029] Figure 7 This is a one-way valve that can be used in Example 1;

[0030] Figure 8 This is a control structure as described in Example 2.

[0031] In the diagram: 1. Cooling oil passage; 101. Oil suction line one; 102. Oil return line; 2. Electronic oil pump; 3. Heat exchanger; 4. Directional oil passage; 401. Oil suction line two; 402. Oil delivery line; 4020. Oil collection and distribution chamber; 4021. Branch line one; 4022. Branch line two; 5. Mechanical pump; 6. Connecting line; 7. Check valve; 701. Valve chamber; 702. Valve ball; 703. Tapered orifice; 8. Pressure control device; 801 8011 Cylinder liner body; 80111 Upper cylinder chamber; 80112 Lower cylinder chamber; 8012 Oil inlet; 8013 Oil outlet; 8014 Exhaust port; 802 Piston valve; 8021 Valve hole; 803 Compression spring; 804 Upper limit post; 805 Lower limit post; 806 Bolt body; 9 Hydraulic pipe; 10 Right first and second gear shaft; 11 Bottom lubricating oil; 12 Solenoid valve one; 13 Solenoid valve two. Detailed Implementation

[0032] like Figure 1As shown in Figure 3, this invention relates to a lubricating oil cooling system (hereinafter referred to as the oil cooling system) and a directional active lubrication system (hereinafter referred to as the directional lubrication system) for a mining truck gearbox. The oil cooling system includes a cooling oil passage 1 consisting of an oil suction line 101 and an oil return line 102, an electronic oil pump 2 located between the oil suction line 101 and the oil return line 102, and a heat exchanger 3 located on the oil return line 102. The directional lubrication system includes a directional oil passage 4 consisting of an oil suction line 401 and an oil delivery line 402, and a mechanical pump 5 located between the oil suction line 401 and the oil delivery line 402.

[0033] In the prior art, the electronic oil pump 2 of the oil cooling system draws lubricating oil 11 from the bottom of the gearbox through the oil suction pipe 101, and then flows back to the bottom of the gearbox after being cooled by the heat exchanger 3 installed on the oil return pipe 102, thereby achieving appropriate cooling of all components in the gearbox.

[0034] The directional lubrication system's oil delivery line 402 can branch into multiple branches as needed, such as... Figure 3 , 4 The oil supply line 402 shown has branched into branch line 4021 and branch line 4022. Branch line 4021 mainly runs along the axis of the right first and second gear shaft 10 and the right third and fourth gear shafts, while branch line 4022 mainly runs along the axis of the left first and second gear shafts and the left third and fourth gear shafts. Branch lines 4021 and 4022 can further branch to the components that require directional lubrication. Under operating conditions, the right first and second gear shaft 10 drives the mechanical pump 5 to rotate, drawing lubricating oil 11 from the bottom of the gearbox through the suction line 401, and then delivering it to the various components that require directional lubrication via the oil supply line 402.

[0035] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1

[0036] like Figure 1As shown in Figure 6, a method for providing supplemental lubrication to a directional lubrication system using an oil cooling system involves establishing a connecting pipe 6 between the upstream section of the return oil pipe 102 of the cooling oil passage 1 of the oil cooling system (preferably after the heat exchanger 3) and the oil supply pipe 402 of the directional lubrication system's directional oil passage 4. When the directional lubrication system cannot supply lubricating oil to the directional lubrication components in a timely and sufficient manner, the oil cooling system supplies lubricating oil to the oil supply pipe 402 of the directional lubrication system through the connecting pipe 6. The connecting pipe 6 is closed when the directional lubrication system can supply oil normally. In this way, when the directional lubrication system does not supply lubricating oil to the components requiring directional lubrication in a timely and sufficient manner, the oil cooling system, which is originally independent of the directional lubrication system, temporarily replaces the directional lubrication system to provide the required lubricating oil to the components requiring directional lubrication in a timely manner, preventing dry friction damage to the rotating parts due to lack of or insufficient oil. Since the connecting pipe is located after the heat exchanger 3, all lubricating oil supplied to the directional lubrication system's oil supply pipes is cooled by the heat exchanger. Therefore, the cooling effect on the gearbox is not affected at all during the process of the oil cooling system serving the directional lubrication system. Here, the inability to supply lubricating oil to each directional lubrication component in a timely and sufficient manner generally refers to the initial stage of starting the mining truck, when the wheel shaft in the gearbox begins to rotate, but due to the low speed in the initial stage, the mechanical pump does not pump enough oil and the oil circuit is too long.

[0037] Furthermore, when lubricating oil is supplied to the oil supply line 402 of the directional lubrication system via the connecting line 6 at the front section of the return oil line 102 of the cooling oil passage 1, the rear section of the return oil line 102 is closed. When the connecting line 6 is closed, the rear section of the return oil line 102 of the oil cooling system is opened, and the cooled lubricating oil flows back to the bottom of the gearbox via the return oil line 102. In this way, when necessary, all the lubricating oil ejected by the electronic oil pump 2 can be supplied to the oil supply line 402. After the oil supply to the oil supply line 402 is completed, the oil cooling system and the directional lubrication system can independently perform their respective functions.

[0038] The measures taken to achieve the alternating closure and opening of the connecting pipeline 6 and the return oil pipeline 102 include setting up a control mechanism between the oil cooling system and the directional lubrication system.

[0039] In this embodiment, the measures also include setting the oil pressure of the return oil line 102 of the cooling oil passage 1 to be lower than the oil pressure of the delivery oil line 402 of the directional oil passage 4 under normal operating conditions, and setting the oil pressure of the return oil line 102 to be higher than the oil pressure of the delivery oil line 402 under abnormal operating conditions when the mechanical pump 5 of the directional lubrication system is running at a low speed.

[0040] The control mechanism includes a check valve 7, controlled by a pressure difference, installed on the connecting pipeline 6, allowing only flow to the oil supply pipeline 402; and a pressure control device 8, installed between the downstream section of the return oil pipeline 102 and the oil supply pipeline 402, for opening and closing the downstream section of the return oil pipeline 102. When the oil pressure in the oil supply pipeline 402 is lower than the oil pressure in the return oil pipeline 5, the check valve 7 automatically opens the connecting pipeline 6, and the pressure control device 8 automatically closes the downstream section of the return oil pipeline 102 of the oil cooling system. When the oil supply pipeline 402 has the oil pressure under normal operating conditions, the check valve 7 automatically closes the connecting pipeline 6, and the pressure control device 8 automatically opens the downstream section of the return oil pipeline 102. This embodiment provides a check valve 7 as described below:

[0041] like Figure 7 As shown, the one-way valve 7 has a valve chamber 701, inside which is a valve ball 702. The valve chamber 701 is a cylindrical cavity with a diameter larger than that of the valve ball 702. The bottom of the valve chamber 701 has a conical hole 703. When the valve ball 702 falls into the conical hole 703, it can block the conical hole 703. The upper part of the valve chamber 701 is connected to the upper section of the connecting pipe 6, and the lower end of the conical hole 703 is connected to the lower section of the connecting pipe 6. When the oil pressure in the return oil pipe 102 is greater than the oil pressure in the supply oil pipe 402, the lubricating oil in the lower section of the connecting pipe 6 pushes up the valve ball 702. The lubricating oil flows upward from the conical hole 703 through the gap between the valve ball 702 and the inner wall of the valve chamber 701, thus putting the one-way valve 7 in the open state. When the oil pressure in the return oil line 102 is less than the oil pressure in the delivery oil line 402, the valve ball 702 falls back, the conical orifice 703 is blocked, and the check valve 7 is in the closed state.

[0042] like Figure 4 As shown in Figure 6, the pressure control device 8 includes a cylinder liner 801 with a cylinder cavity 8011. A piston valve 802 is provided in the cylinder cavity 8011, dividing the cylinder cavity 8011 into an upper cylinder cavity 80111 and a lower cylinder cavity 80112. The upper cylinder cavity 80111 is connected to the oil supply line 402. A compression spring 803 is provided in the lower cylinder cavity 80112, which is pressed by the piston valve 802. A valve hole 8021 is provided on the piston valve 802, which is open to the left and right. An oil inlet hole 8012 connecting to the front section of the return oil line and an oil outlet hole 8013 connecting to the rear section of the return oil line 102 are respectively provided on the left and right cylinder walls of the cylinder cavity 8011. Thus, when the piston valve 802 is pushed up by the compression spring 803 so that the valve hole 8021 is higher than the oil inlet hole 8012 and oil outlet hole 8013 on both sides, the rear section of the return oil pipeline 102 is closed. When the valve hole 8021 of the piston valve 802 is connected to the oil inlet hole 8012 and oil outlet hole 8013 on both sides at the same height, the rear section of the return oil pipeline 102 is opened.

[0043] The bottom of the cylinder liner body 801 is provided with a threaded hole with a diameter greater than or equal to that of the cylinder cavity 8011. The bottom of the cylinder cavity 8011 is a bolt body 806 that is screwed into the threaded hole from bottom to top. The lower limit post is fixed on the bolt body 806, which makes it easy to install the piston valve 802 from the threaded hole.

[0044] Additionally, an exhaust port 8014 is provided in the lower cylinder chamber 80112.

[0045] Furthermore, the piston valve 802 is positioned to the upper limit, causing the piston valve 802 to pre-compress the compression spring 803. When the oil pressure in the oil supply line 402 is lower than the oil pressure in the return line 102, the oil pressure in the upper cylinder chamber 80111 is insufficient to overcome the pre-compression force of the compression spring 803, thus preventing the piston valve 802 from descending and keeping the latter part of the return line 102 closed. The piston valve 802 is then positioned to the lower limit. When the oil pressure in the oil supply line 402 is higher than the oil pressure in the return line 102, the oil pressure in the upper cylinder chamber 80111 is sufficient to overcome the pre-compression force of the compression spring 803, causing the piston valve 802 to descend and stop at the lower limit. This ensures that the valve port 8021 of the piston valve 802 is connected at the same height to the oil inlet port 8012 and the oil outlet port 8013 on both sides, thereby opening the latter part of the return line 102 of the oil cooling system.

[0046] The above-mentioned upper limit position of piston valve 802 is specifically achieved by setting an upper limit position post 804 at the top of piston valve 802 that can abut against the top wall of upper cylinder chamber 80111; the above-mentioned lower limit position of piston valve 802 is specifically achieved by setting a lower limit position post 805 at the bottom of lower cylinder chamber 80112 that can abut against the bottom end of piston valve 802.

[0047] The control mechanism includes setting up an oil distribution chamber 4020 on the oil pipeline 402, connecting the connecting pipeline 6 to the oil distribution chamber 4020, connecting the upper cylinder chamber 80111 to the oil distribution chamber 4020 through the hydraulic pipe 9, and branching off all branches of the oil pipeline 402 from the oil distribution chamber 4020.

[0048] The above method, when applied to the initial stage of mining card startup, includes the following steps:

[0049] S1. Start the electronic oil pump 2 of the oil cooling system. The lubricating oil pumped out by the electronic oil pump 2 first enters the oil delivery pipeline 402 of the directional oil passage 4 of the directional lubrication system through the connecting pipeline 6, and is delivered to each directional lubrication component in a timely and sufficient manner along the oil delivery pipeline 402. During this process, the latter part of the oil return pipeline 102 of the oil cooling system is closed.

[0050] S2. Start the mining truck. The wheel shaft in the gearbox rotates. The mechanical pump 5 of the directional lubrication system starts synchronously. The speed is not high enough to make the oil pressure in the oil supply line 402 greater than the oil pressure in the return line 102. The directional lubrication components still rely on the lubricating oil pumped out by the electronic oil pump 2 for lubrication.

[0051] S3. When the gearbox shafts reach normal operating conditions, the mechanical pump 5 rotates to a speed that makes the oil pressure in the oil supply line 402 greater than the oil pressure in the return line 102. The one-way valve 7 closes the connecting line 6, and the pressure control device 8 opens the latter part of the return line. The directional lubrication system and the oil cooling system each perform their respective functions. Example 2

[0052] like Figure 8 As shown, the difference between this embodiment and Embodiment 1 is that the control mechanism includes a control system, a solenoid valve 12 on the connecting pipeline 6, a solenoid valve 13 on the return oil pipeline 102, and oil pressure sensor 1 (not shown in the figure) and oil pressure sensor 2 (not shown in the figure) on the directional oil passage 4 and the cooling oil passage 1, respectively. The control system controls solenoid valve 12 to open or close the connecting pipeline 6 and controls solenoid valve 13 to open or close the return oil pipeline 102.

[0053] The above embodiments are only used to describe the present invention more clearly, and should not be regarded as limiting the scope of protection covered by the present invention. Any equivalent modifications should be regarded as falling within the scope of protection covered by the present invention.

Claims

1. A method for providing supplemental lubrication to a directional lubrication system using an oil cooling system, characterized in that, A connecting pipe (6) is installed between the front section of the return oil pipe (102) of the cooling oil passage (1) of the oil cooling system and the oil supply pipe (402) of the directional lubrication system (4). When the directional lubrication system cannot supply lubricating oil to each directional lubrication component in a timely and sufficient manner, the oil cooling system supplies lubricating oil to the oil supply pipe (402) of the directional lubrication system through the connecting pipe (6). The connecting pipe (6) is closed when the directional lubrication system can supply oil normally. When the front section of the oil supply line (102) delivers lubricating oil to the oil supply line (402) of the directional lubrication system through the connecting line (6), the rear section of the return line (102) is closed. When the connecting line (6) is closed, the rear section of the return line (102) of the oil cooling system is opened. To achieve the alternating closure and opening of the connecting line (6) and the return line (102), the measures taken include setting up a control mechanism between the oil cooling system and the directional lubrication system. The measures also include setting up a return line of the cooling oil passage (1). The oil pressure in the return oil line (102) is lower than the oil pressure in the delivery oil line (402) of the directional oil passage (4) under normal operating conditions. Under abnormal operating conditions where the mechanical pump (5) of the directional lubrication system operates at a low speed, the oil pressure in the return oil line (102) is higher than the oil pressure in the delivery oil line (402). The aforementioned control mechanism includes a check valve (7) on the connecting pipeline (6) that can only flow to the delivery oil line (402) and is controlled by the pressure difference between the upper and lower parts. A check valve (7) is installed between the downstream section of the return oil line (102) and the delivery oil line (402). The pressure control device (8) is used to switch the downstream section of the return oil pipeline (102); when the oil pressure of the oil supply pipeline (402) is lower than the oil pressure of the return oil pipeline (102), the check valve (7) automatically opens the connecting pipeline (6), and the pressure control device (8) automatically closes the downstream section of the return oil pipeline (102) of the oil cooling system; when the oil supply pipeline (402) has the oil pressure under normal operating conditions, the check valve (7) automatically closes the connecting pipeline (6), and the pressure control device (8) automatically opens the downstream section of the return oil pipeline (102);The pressure control device (8) includes a cylinder liner (801) with a cylinder chamber (8011). A piston valve (802) is provided in the cylinder chamber (8011), dividing the cylinder chamber (8011) into an upper cylinder chamber (80111) and a lower cylinder chamber (80112). The upper cylinder chamber (80111) is connected to the oil supply line (402). A compression spring (803) pre-compressed by the piston valve (802) is provided in the lower cylinder chamber (80112). A valve hole (8021) is provided on the piston valve (802) that passes through from left to right. The left and right cylinder walls are respectively provided with an oil inlet hole (8012) connecting the front section of the return oil pipeline and an oil outlet hole (8013) connecting the rear section of the return oil pipeline (102). When the piston valve (802) is pushed up by the compression spring (803) so that the valve hole (8021) is higher than the oil inlet holes (8012) and oil outlet holes (8013) on both sides, the rear section of the return oil pipeline (102) is closed. When the valve hole (8021) of the piston valve (802) is at the same height as the oil inlet holes (8012) and oil outlet holes (8013) on both sides, the rear section of the return oil pipeline (102) is open.

2. The method for providing supplemental lubrication to a directional lubrication system using an oil cooling system as described in claim 1, characterized in that, The piston valve (802) is positioned to the upper limit, causing it to pre-compress the spring (803). When the oil pressure in the oil supply line (402) is lower than the oil pressure in the return line (102), the oil pressure in the upper cylinder chamber (80111) is insufficient to overcome the pre-compression force of the spring (803), thus preventing the piston valve (802) from moving downward and keeping the latter part of the return line (102) closed. The piston valve (802) is then positioned to the lower limit. When the oil pressure in the oil supply line (402) is higher than the oil pressure in the return line (102), the oil pressure in the upper cylinder chamber (80111) can overcome the pre-compression force of the compression spring (803) to make the piston valve (802) move downward and stop at the lower limit, so as to ensure that the valve hole (8021) of the piston valve (802) is connected at the same height with the oil inlet hole (8012) and oil outlet hole (8013) on both sides, and the latter part of the return line (102) of the oil cooling system is opened.

3. The method for providing supplemental lubrication to a directional lubrication system using an oil cooling system as described in claim 2, characterized in that, The upper limit of the piston valve (802) is achieved by setting an upper limit post (804) at the top of the piston valve (802) that can abut against the top wall of the upper cylinder chamber (80111), and the lower limit of the piston valve (802) is achieved by setting a lower limit post (805) at the bottom of the lower cylinder chamber (80112) that can abut against the bottom end of the piston valve (802).

4. The method for providing supplemental lubrication to a directional lubrication system using an oil cooling system as described in claim 1, characterized in that, The set-up control mechanism includes a control system, a solenoid valve 1 (12) on the connecting pipeline (6), a solenoid valve 2 (13) on the return oil pipeline (102), and an oil pressure sensor 1 and an oil pressure sensor 2 on the directional oil passage (4) and the cooling oil passage (1), respectively. The control system controls the solenoid valve 1 (12) to open or close the connecting pipeline (6) and controls the solenoid valve 2 (13) to open or close the return oil pipeline (102).

5. The method for providing supplemental lubrication to a directional lubrication system using an oil cooling system as described in any one of claims 1-4, characterized in that, The initial phase of a mining card startup includes the following steps: S1. Turn on the electronic oil pump (2) of the oil cooling system. The lubricating oil pumped out by the electronic oil pump (2) first enters the oil delivery pipeline (402) of the directional oil passage (4) of the directional lubrication system through the connecting pipeline (6), and reaches each directional lubrication component in a timely and sufficient manner along the oil delivery pipeline (402). During this process, the back section of the oil return pipeline (102) of the oil cooling system is closed. S2. Start the mining truck. The wheel shaft in the gearbox rotates. The mechanical pump (5) of the directional lubrication system starts synchronously. The speed is not high enough to make the oil pressure in the oil delivery line (402) greater than the oil pressure in the return line (102). The directional lubrication components still rely on the lubricating oil pumped out by the electronic oil pump (2) for lubrication. S3, the gearbox shafts in the gearbox reach the working condition, the mechanical pump (5) speed reaches the point where the oil pressure in the oil supply line (402) is greater than the oil pressure in the return line (102), the one-way valve (7) closes the connecting line (6), the pressure control device (8) opens the back section of the return line, and the directional lubrication system and the oil cooling system each perform their respective functions.

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