Lubrication device

Abstract

To provide a lubrication device capable of increasing a temperature of low-temperature oil of a transmission even during stop of a vehicle.SOLUTION: When an oil temperature is below a predetermined temperature threshold (YES in step S1), a control unit drives an electric oil pump at a faster rotation speed than when the oil temperature is equal to or higher than the predetermined temperature threshold (step S2). When the oil temperature is below the predetermined temperature threshold, the control unit drives the electric oil pump at a faster rotation speed the lower the oil temperature is.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a lubrication system. [Background technology]

[0002] Patent document 1 describes an oil supply system that improves the rate at which the oil heats up by including a mechanical pump that supplies oil to multiple parts, and an electric pump that supplies oil as lubricating oil to a variator of a continuously variable transmission, which generates a particularly large amount of heat among the multiple parts, when the oil temperature is below a first temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-21588 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technique described in Patent Document 1 has a problem in that the oil cannot be heated while the vehicle is stopped because the continuously variable transmission does not generate heat.

[0005] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to provide a lubrication device capable of raising the temperature of low-temperature oil in a transmission even when the vehicle is stopped. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a lubrication device comprising an electric oil pump arranged inside a transmission for pumping oil, and a control unit for controlling the electric oil pump, wherein the control unit drives the electric oil pump at a faster rotational speed when the oil temperature is below a predetermined temperature threshold than when the oil temperature is equal to or higher than the predetermined temperature threshold. Effect of the Invention

[0007] In this way, according to the present invention, it is possible to increase the temperature of low-temperature oil in the transmission even when the vehicle is stopped. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a transmission equipped with a lubrication device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a flowchart showing the procedure of the oil temperature control operation by the lubrication device according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a low temperature map referenced in the oil temperature control operation by the lubrication device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A lubrication device according to one embodiment of the present invention is a lubrication device that is disposed inside a transmission and includes an electric oil pump that pumps oil, and a control unit that controls the electric oil pump, and the control unit is characterized in that when the oil temperature is below a predetermined temperature threshold, the control unit drives the electric oil pump at a faster rotation speed than when the oil temperature is equal to or higher than the predetermined temperature threshold. This allows the lubrication device according to one embodiment of the present invention to heat up the low-temperature oil in the transmission even when the vehicle is stopped. EXAMPLES

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle equipped with a lubrication device according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0011] In FIG. 1, a vehicle 30 includes an internal combustion engine 1, a transmission 2 that transmits the output of the internal combustion engine 1 to a drive shaft, a hydraulic circuit 3 of the transmission 2, and a control unit 4.

[0012] Oil for lubricating a transmission mechanism (not shown) is stored inside the transmission 2. The oil inside the transmission 2 is scooped up by gears and the like of the transmission mechanism and is supplied to parts that require lubrication.

[0013] Also provided inside the transmission 2 are a mechanical oil pump 5 that is driven by the power of the internal combustion engine 1 to pump oil, and an electric oil pump 7 that is driven by the power source of the battery 6 to pump oil. The oil inside the transmission 2 is pumped by the mechanical oil pump 5 and the electric oil pump 7, and thereby supplied to parts that require lubrication.

[0014] The mechanical oil pump 5 is equipped with a strainer 9 that draws up oil from an oil pan 8, a first oil passage 10 that guides the oil drawn up from the strainer 9 to the suction port side, and a second oil passage 11 that guides the oil from the discharge port side to the hydraulic circuit 3. The mechanical oil pump 5 is driven by utilizing the rotation transmitted from the internal combustion engine 1 to an input shaft (not shown) of the transmission 2.

[0015] The electric oil pump 7 includes a strainer 12 that draws up oil from the oil pan 8, a first oil passage 13 that guides the oil drawn up from the strainer 12 to the suction port side, and a second oil passage 14 that guides the oil from the discharge port side to the hydraulic circuit 3. The electric oil pump 7 and the control unit 4 constitute the lubrication device of the present invention.

[0016] A check valve 15 is provided in the second oil passage 14 on the discharge port side of the electric oil pump 7. The check valve 15 prevents the oil pumped up by the mechanical oil pump 5 from leaking from the electric oil pump 7 to the oil pan 8.

[0017] The second oil passage 11 of the mechanical oil pump 5 and the second oil passage 14 of the electric oil pump 7 are integrated into one and connected to a third oil passage 16. The third oil passage 16 is connected to the hydraulic circuit 3, and sends the oil pumped up by the mechanical oil pump 5 and the electric oil pump 7 to the hydraulic circuit 3.

[0018] The third oil passage 16 is provided with a line pressure solenoid 17, an oil temperature sensor 18, and an oil pressure sensor 19. The line pressure solenoid 17 is a hydraulic pressure adjustment mechanism that supplies the oil pumped up by the mechanical oil pump 5 and the electric oil pump 7 to the hydraulic circuit 3 at a predetermined hydraulic pressure.

[0019] The hydraulic circuit 3 operates the starting clutch and the switching mechanism of the auxiliary transmission by the hydraulic pressure of the supplied oil, and transmits the driving force of the internal combustion engine 1 to the drive shaft. The oil used in the hydraulic circuit 3 is returned to the oil pan 8 through the return oil passage 20.

[0020] The oil temperature sensor 18 measures the temperature of the oil (hereinafter also referred to as the oil temperature) and outputs the result to the control unit 4. The oil pressure sensor 19 measures the oil pressure regulated by the line pressure solenoid 17 and outputs the result to the control unit 4.

[0021] The oil temperature sensor 18 measures the temperature of the oil supplied to the hydraulic circuit 3 and outputs it to the control unit 4. The oil pressure sensor 19 measures the oil pressure of the oil supplied to the hydraulic circuit 3 and outputs it to the control unit 4. The crank angle sensor 21 detects the rotation speed of the internal combustion engine 1 and outputs it to the control unit 4. The ignition switch 22 is operated by the occupant to start and stop the internal combustion engine 1, manages the ON / OFF of the ignition power supply of the internal combustion engine 1, and outputs the ON / OFF state to the control unit 4.

[0022] The rotation speed sensor that detects the rotation speed of the internal combustion engine 1 is not limited to the crank angle sensor 21, and may be replaced with another sensor that can detect the rotation speed of the internal combustion engine 1. For example, it may be a sensor that detects the rotation speed of the transmission 2 that receives an input from the internal combustion engine 1.

[0023] The control unit 4 is composed of a computer unit equipped with a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, etc., an input port, and an output port.

[0024] The ROM of these computer units stores various constants, various maps, and the like, as well as programs for causing the computer units to function as the control unit 4. That is, the CPU executes the programs stored in the ROM using the RAM as a working area, causing these computer units to function as the control unit 4 in this embodiment.

[0025] An oil temperature sensor 18, an oil pressure sensor 19, a crank angle sensor 21 which is a rotation speed sensor, and an ignition switch 22 are connected to the input side of the control unit 4. On the other hand, an electric oil pump 7 and a line pressure solenoid 17 are connected to the output side of the control unit 4.

[0026] The control unit 4 measures the magnitude of the hydraulic pressure supplied to the hydraulic circuit 3 by the line pressure solenoid 17 using a hydraulic pressure sensor 19, and adjusts the hydraulic pressure by performing feedback control so as to obtain a target hydraulic pressure.

[0027] In addition, the control unit 4 controls the electric oil pump 7 based on the oil temperature detected by the oil temperature sensor 18.

[0028] Here, the mechanical loss in the transmission 2 includes loss due to agitation resistance according to the viscosity of the oil. The viscosity and agitation resistance of the oil exponentially increase as the oil temperature decreases. Therefore, in order to reduce the agitation resistance of the oil and improve fuel efficiency, it is desirable to raise the temperature of low-temperature oil as soon as possible when starting the vehicle 30 from a low-temperature state (cold start).

[0029] The oil is heated by the heat generated by the electric oil pump 7, and its viscosity decreases. The oil also generates heat due to the agitation resistance (shear stress) when pumped by the electric oil pump 7, and its temperature increases and its viscosity decreases. The heat generated by the agitation resistance in the electric oil pump 7 increases the faster the rotation speed of the electric oil pump 7. For this reason, the faster the rotation speed of the electric oil pump 7, the more rapidly the oil temperature increases and the viscosity decreases.

[0030] When the oil temperature is below a predetermined temperature threshold, the control unit 4 drives the electric oil pump 7 at a faster rotation speed than when the oil temperature is equal to or higher than the predetermined temperature threshold.

[0031] When the oil temperature is below a predetermined temperature threshold, the control unit 4 drives the electric oil pump 7 at a faster rotation speed as the oil temperature is lower.

[0032] Next, the oil temperature control operation by the control unit 4 will be described with reference to Fig. 2. This oil temperature control operation is repeatedly executed while the system is running.

[0033] The control unit 4 determines whether or not the oil temperature is below the temperature threshold value (step S1). If the oil temperature is not below the temperature threshold value (NO in step S1), the control unit 4 continues step S1.

[0034] If the oil temperature is lower than the temperature threshold value (YES in step S1), the control unit 4 drives the electric oil pump 7 in accordance with the low temperature map (step S2), and ends this operation.

[0035] Next, the low temperature map will be described with reference to Fig. 3. This low temperature map defines the relationship between the oil temperature and the increase in the rotation speed of the electric oil pump 7 (referred to as the rotation speed increase amount in the figure), and is stored in the ROM of the control unit 4.

[0036] 3, the rotation speed increase amount is set to 100 rpm when the oil temperature is 0° C. When the oil temperature is 0° C., the control unit 4 drives the electric oil pump 7 at a rotation speed obtained by adding 100 rpm to the reference rotation speed.

[0037] Similarly, when the oil temperature is -10°C, -20°C, and -30°C, the rotation speed increase amount is set to 200 rpm, 300 rpm, and 400 rpm, respectively. Therefore, the lower the oil temperature, the faster the rotation speed is driven by the control unit 4. Note that the control unit 4 stores not only the low temperature map, but also a normal map (not shown) that is referenced when the oil temperature is equal to or higher than the temperature threshold value.

[0038] As described above, in this embodiment, when the oil temperature is below the predetermined temperature threshold, the control unit 4 drives the electric oil pump 7 at a faster rotation speed than when the oil temperature is equal to or higher than the predetermined temperature threshold.

[0039] As a result, when the oil temperature is below a predetermined temperature threshold, the electric oil pump 7 is driven at a high rotation speed, which increases the amount of heat generated by the oil stirring resistance and promotes the rise in oil temperature. As a result, the low-temperature oil in the transmission 2 can be heated even when the vehicle 30 is stopped.

[0040] Furthermore, in this embodiment, when the oil temperature is below a predetermined temperature threshold, the controller 4 drives the electric oil pump 7 at a faster rotation speed as the oil temperature is lower.

[0041] As a result, the electric oil pump 7 is driven at a faster rotation speed as the oil temperature decreases, and thus the lower the oil temperature, the more the oil temperature can be promoted to increase.

[0042] Although an embodiment of the invention has been disclosed, it will be apparent to one of ordinary skill in the art that modifications may be made thereto without departing from the spirit and scope of the invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0043] 2 Transmission 4 Control section (lubrication device) 7 Electric oil pump (lubrication system)

Claims

1. An electric oil pump that is disposed inside the transmission and pumps oil; A lubrication device comprising: a control unit that controls the electric oil pump, A lubrication device characterized in that, when the oil temperature is below a predetermined temperature threshold, the control unit drives the electric oil pump at a faster rotational speed than when the oil temperature is equal to or higher than the predetermined temperature threshold.

2. The lubrication device according to claim 1 , wherein, when the oil temperature is lower than a predetermined temperature threshold, the control unit drives the electric oil pump at a higher rotation speed as the oil temperature is lower.

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