Oil tank for dry sump lubrication system

Abstract

To effectively prevent lubricating oil from leaking from an outlet for discharging gas even when the oil level is greatly inclined, thereby achieving miniaturization. [Solution] An oil tank 4 of a dry sump lubrication system that stores lubricating oil pumped from an oil pan, delivers the lubricating oil 3 to specified locations requiring lubrication, and discharges gas separated from the lubricating oil 3, is equipped with multiple outlets 10a, 10b for discharging gas provided on an upper plate portion 9 that closes the upper end, a valve mechanism 11 that opens and closes the outlets 10a, 10b, and a valve control unit 15 that operates based on acceleration to operate the valve mechanism 11, and the valve control unit 15 is configured to operate the valve mechanism 11 to close the outlets 10a, 10b located on the side where the oil level 3a of the lubricating oil 3 becomes higher due to acceleration, and to open the outlet located on the side where the oil level 3a becomes lower.

Description

[Technical Field]

[0001] The present invention relates to a dry-sump type lubrication system, and more particularly to an oil tank for temporarily storing lubricating oil. [Background technology]

[0002] A dry-sump engine lubrication system is configured such that lubricating oil from the oil pan is pumped into an oil tank by a scavenging pump, where the liquid and gaseous components are separated. The liquid component is then supplied to parts of the engine and other components requiring lubrication by a pump, while the gaseous component (such as blow-by gas) is recirculated into the engine's intake system. This type of lubrication system is described in Patent Documents 1 and 2.

[0003] In the system described in Patent Document 1, the lubricating oil in the oil pan is returned to the oil tank by a main discharge pump, while the lubricating oil in the cylinder head is returned to the oil tank by a sub-discharge pump. The lubricating oil accumulated in the oil tank is then supplied to designated lubrication points by a supply pump. In addition, gaseous components such as blow-by gas separated from the lubricating oil inside the oil tank are returned to the engine's intake system through a discharge port located in the upper center of the oil tank.

[0004] Furthermore, the dry sump lubrication system described in Patent Document 2 uses a specially designed oil tank, consisting of an inner and outer double tank. Lubricating oil returned from the oil pan by a scavenge pump is supplied to the inner circumferential surface of the inner tank in a spiral flow, and the gas separated as a result is returned to the engine's intake system through a gas outlet located at the top center of the oil tank. Multiple through-holes are formed in the upper outer wall of the inner tank, allowing the spirally flowing lubricating oil to flow out of the inner tank. A shielding tube is provided on the outer periphery of the through-holes, which captures the lubricating oil that flows out of the inner tank through the through-holes and allows it to flow downward to the bottom of the oil tank. A second gas outlet is provided at a predetermined location on the top plate of the oil tank, outer periphery of the shielding tube, and the shielding tube prevents the lubricating oil from reaching the second gas outlet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4284952 [Patent Document 2] Japanese Utility Model Application Publication No. 03-095015 Summary of the Invention [Problem to be solved by the invention]

[0006] Dry sump lubrication systems are primarily used to ensure a stable supply of lubricating oil even under high acceleration (high G). Furthermore, by providing an oil tank separate from the oil pan, it is possible to increase the lubricating oil capacity. Therefore, when high acceleration occurs inside the oil tank, the oil level tilts significantly, which can cause lubricating oil to leak out of the gas outlet, which is always open.

[0007] The oil tank described in Patent Document 1 has a gas outlet located in the upper center. Therefore, even if a large acceleration is applied in the front-to-back or left-to-right direction, the lubricating oil will not leak from the outlet unless the oil level, tilted by the acceleration, reaches the outlet. Furthermore, because the outlet is located in the upper center, the structural limitations on the acceleration that can prevent the lubricating oil from leaking can be minimized. However, one of the advantages of a dry sump lubrication system is that it can increase the lubricating oil capacity. Therefore, if the amount of lubricating oil in the oil tank is increased and the oil level rises, even if the oil level tilts due to a small acceleration, the oil level will reach the outlet, making it more likely for the lubricating oil to leak out.

[0008] The same situation applies to the oil tank described in Patent Document 2: if the oil level tilts due to acceleration when the amount of lubricating oil is large, the tilted oil level will reach the gas outlet, making it easier for the lubricating oil to leak out. In particular, in the structure described in Patent Document 2, the second gas outlet is provided at a location away from the center, so if acceleration occurs that raises the oil level on the second gas outlet side, the tilted oil level will reach the second gas outlet with a small acceleration, making it easier for the lubricating oil to leak out.

[0009] The present invention has been made with an eye on the above-mentioned technical problems, and aims to provide an oil tank for a dry sump lubrication system that can effectively prevent lubricating oil from leaking from the exhaust port that releases gas even when the oil level is greatly inclined, and that can thereby be made smaller. [Means for solving the problem]

[0010] To achieve the above objective, the present invention provides an oil tank for a dry-sump type lubrication system that stores lubricating oil drawn from an oil pan, delivers the lubricating oil to a predetermined lubrication site, and discharges gaseous components separated from the lubricating oil, comprising: a plurality of discharge ports for discharging the gaseous components provided on an upper plate portion with a closed upper end; a valve mechanism for opening and closing the discharge ports; and a valve control unit that operates the valve mechanism based on acceleration, wherein the valve control unit is configured to operate the valve mechanism in a state where, among the plurality of discharge ports, the discharge port located on the side where the oil level of the lubricating oil rises due to the acceleration is closed, and the discharge port located on the side where the oil level falls is opened. [Effects of the Invention]

[0011] In the oil tank of this invention, when subjected to acceleration, the lubricating oil stored inside is pushed in the direction of the acceleration, causing the oil level to tilt relative to the horizontal plane. Based on this acceleration, the valve control unit operates the valve mechanism. The valve mechanism operates by closing the outlet located on the side where the oil level rises due to the tilt, and opening the outlet located on the opposite side where the oil level falls. Therefore, even when the tilted oil level reaches the upper plate, it is possible to prevent leakage from the outlet. Also, since the other outlet is open, gaseous components such as blow-by gas can be discharged. Furthermore, because the outlet located on the side where the oil level falls is off-center from the upper plate, the maximum tilt angle of the oil level at which the tilted oil level reaches the open outlet, i.e., the maximum acceleration at which lubricating oil does not leak from the outlet, can be made larger compared to when the outlet is located in the center of the upper plate. Therefore, according to this invention, the amount of lubricating oil that can be stored can be increased. In other words, it becomes possible to miniaturize the oil tank. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram for explaining the configuration of a dry sump lubrication system to which an embodiment of the present invention is applied. FIG. [Figure 2](a) is a schematic diagram illustrating the configuration of an oil tank in an embodiment of the present invention, and (b) is a schematic diagram of its valve mechanism viewed from below. [Figure 3] (a) is a schematic diagram showing the inclination of the oil surface when acceleration is applied to the left, and (b) is a schematic diagram of the valve mechanism viewed from below. [Figure 4] (a) is a schematic diagram showing the inclination of the oil surface when acceleration is applied to the right, and (b) is a schematic diagram of the valve mechanism viewed from below. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the embodiment described below is merely an example of how the present invention can be implemented, and is not intended to limit the present invention.

[0014] The oil tank in the embodiment of the present invention is an oil tank used in a dry sump lubrication system. To briefly explain the dry sump lubrication system, in FIG. 1, reference numeral "1" indicates an engine, at the bottom of which an oil pan 2 is provided. The dry sump lubrication system is a system that pumps lubricating oil 3 from the oil pan 2 and resupplies it to parts that require lubrication, such as the engine 1, and is provided with a scavenge pump 5 that pumps the lubricating oil 3 from the oil pan 2 and sends it to an oil tank 4. The oil tank 4 is also connected to a supply pump 6 that sends the lubricating oil 3 to parts that require lubrication, such as the engine 1. Furthermore, a return path 8 is provided that returns gases such as blow-by gases that accumulate at the top of the oil tank 4 due to separation of the lubricating oil 3 inside the oil tank 4 to an intake pipe (or intake system) 7 of the engine 1.

[0015] 2(a) and 2(b) are schematic diagrams illustrating the configuration of the oil tank 4 according to an embodiment of the present invention. The oil tank 4 has a sealed cylindrical shape as a whole, and multiple (two in FIG. 2) outlets 10a, 10b are provided in its upper plate portion 9. These outlets 10a, 10b are used to release gases such as blow-by gas that accumulate in the upper part of the oil tank 4 to the outside of the oil tank 4, such as the intake system 7 of the engine 1, via a conduit (not shown). Each outlet is provided at a position that is offset from the center of the upper plate portion 9 (the center of the oil tank 4) toward the outer periphery. More specifically, the outlets 10a, 10b are provided at positions that are symmetrical to each other with respect to the center of the upper plate portion 9.

[0016] Furthermore, a valve mechanism 11 is provided that selectively opens and closes each of the outlets 10a, 10b. The valve mechanism 11 selectively closes one of the outlets 10a, 10b to prevent the lubricating oil 3 from leaking out of either of the outlets 10a, 10b when the oil level 3a is tilted. Therefore, the valve mechanism 11 can be configured as appropriate, such as a shutter that closes the outlets, a valve disc that contacts and separates from a valve seat, a valve disc that rotates inside the outlets 10a, 10b to open and close, or a plug that opens and closes by inserting and removing it. In the embodiment described here, the valve mechanism 11 is configured to close each of the outlets 10a, 10b by a corresponding shutter 12a, 12b.

[0017] Figure 2(b) is a schematic diagram illustrating the valve mechanism 11, showing the shutters 12a and 12b viewed from below in the vertical direction. The shutters 12a and 12b are plate-shaped members with the same shape as the openings of the corresponding outlets 10a and 10b, and are provided at the tip of the arm 13. A rotation shaft 14 is provided that passes vertically through the center of the upper plate portion 9 or the center of the line connecting the outlets 10a and 10b, and the arm 13 is attached to the lower end of the rotation shaft 14. That is, the arm 13 rotates on a horizontal plane (a plane parallel to the upper plate portion 9) about the rotation shaft 14. The distance from the center of rotation of the arm 13 to each of the shutters 12a, 12b is the same as the distance from the rotation axis 14 to each of the discharge outlets 10a, 10b, and therefore, when the shutters 12a, 12b rotate together with the arm 13, the shutters 12a, 12b open and close each of the discharge outlets 10a, 10b.

[0018] Furthermore, as shown in Figure 2(b), the arm 13 is bent in the middle. The angle of this bend is such that when one shutter 12a(12b) coincides with one outlet 10a(10b) and closes that outlet 10a(10b), the other shutter 12b(12a) moves away from the other outlet 10b(10a) and opens that outlet 10b(10a). In the example shown in Figure 2(b), when one shutter 12a(12b) overlaps one outlet 10a(10b) by about half, the arm 13 is bent so that the other shutter 12b(12a) similarly overlaps the other outlet 10b(10a) by about half.

[0019] A valve control unit 15 is provided, which operates the valve mechanism 11 to open and close the discharge ports 10a and 10b. The valve control unit 15 operates the valve mechanism 11 based on the acceleration acting on the oil tank 4, thereby rotating the shutters 12a and 12b together with the rotating shaft 14 and arm 13 to open and close the discharge ports 10a and 10b. The valve control unit 15 may be configured, for example, to include a motor or electromagnetic actuator that operates based on an acceleration signal, or a weight that moves in response to acceleration and a link mechanism that transmits the movement of the weight to the rotating shaft 14. When the rotating shaft 14 is rotated by a motor, the motor is operated by a signal from an appropriate acceleration sensor (not shown). In this case, if the vehicle is equipped with a dry sump lubrication system, an on-board acceleration sensor can be used to operate the motor based on a signal from the acceleration sensor. The acceleration to be detected may be in any direction, such as forward / backward, leftward, or rightward. Therefore, if the oil tank 4 is tilted relative to a horizontal plane, the acceleration that appears as a component force in the forward / backward or leftward / rightward direction depending on the tilt may be detected.

[0020] Next, the operation of the valve mechanism 11 and the valve control unit 15 will be described. The state shown in FIG. 2 illustrates the operating state when no acceleration is occurring. Here, the oil tank 4 is mounted vertically on a vehicle (not shown), and the two outlets 10a, 10b are arranged side by side in the left-right direction (width direction) of the vehicle. As shown in FIG. 2, each shutter 12a, 12b is held in an open (half-open) position for the corresponding outlet 10a, 10b. Gases such as blow-by gas inside the oil tank 4 are discharged to the intake system 7 of the engine 1 through these outlets 10a, 10b. In this state, the oil surface 3a of the lubricating oil 3 is horizontal and does not reach the outlets 10a, 10b.

[0021] In contrast, Figures 3(a) and 3(b) show a state in which the vehicle turns right and the resulting centrifugal acceleration acts to the left. The lubricating oil 3 inside the oil tank 4 is forced to the left by centrifugal force, as shown in Figure 3(a), causing the oil level 3a to tilt, with its highest point reaching the upper plate portion 9. If the acceleration is large or if a large amount of lubricating oil 3 is contained in the oil tank 4, the oil level 3a will reach near the center of the upper plate portion 9, and in this case, the lubricating oil 3 will naturally cover the left-side outlet 10a in Figure 3(a). Meanwhile, because the centrifugal acceleration acts to the left, the valve control unit 15 operates based on this acceleration, causing the rotating shaft 14 and the arm 13 attached to it to rotate to the right, as shown in Figure 3(b). As a result, the left-side outlet 10a in Figure 3 is closed by one of the shutters 12a. Therefore, even if the lubricating oil 3 is shifted to the left in response to acceleration and the oil surface 3a tilts, in other words, even if the lubricating oil 3 climbs up along the inner wall surface of the oil tank 4, the outlet 10a that the lubricating oil 3 covers is closed, so the lubricating oil 3 is prevented from flowing out of the oil tank 4. Note that the other outlet 10b is open, so there is no problem with the discharge of gas.

[0022] The same situation occurs when the vehicle turns left and centrifugal acceleration acts to the right. Figures 4(a) and 4(b) schematically show the state of the lubricating oil 3 and the valve mechanism 11 when centrifugal acceleration acts to the right. The lubricating oil 3 is concentrated to the right side inside the oil tank 4, and the oil level 3a slopes so that it is higher on the right side. That is, the oil level 3a reaches near the center of the upper plate portion 9, and in this case, the lubricating oil 3 naturally covers the outlet 10b on the right side in Figure 4. Meanwhile, the valve control unit 15 operates based on the centrifugal acceleration to the right, and the rotating shaft 14 and the arm 13 attached to it rotate left as shown in Figure 4(b). As a result, the outlet 10b on the right side in Figure 4 is closed by one of the shutters 12b. Therefore, even if the lubricating oil 3 is shifted to the right in response to acceleration and its oil level 3a tilts, in other words, even if the lubricating oil 3 climbs up along the inner wall surface of the oil tank 4, the outlet 10b that the lubricating oil 3 covers is closed, so the lubricating oil 3 is prevented from flowing out of the oil tank 4. Moreover, because the other outlet 10a is open, there is no impediment to the discharge of gas.

[0023] In conclusion, in the above-described embodiment of the present invention, multiple discharge ports 10a, 10b are provided at locations away from the center of the oil tank 4, and one of the discharge ports 10a (10b) that is covered with the lubricating oil 3 when the oil level 3a is inclined is closed by the valve mechanism 11 and the valve control unit 15, while the other discharge port 10b (10a) is closed. This increases the tolerance for uneven distribution of the lubricating oil 3 within the oil tank 4, to the extent that the lubricating oil 3 does not leak to the outside. In other words, the amount of lubricating oil 3 that can be stored in the oil tank 4 can be increased. In other words, the oil tank 4 can be made smaller without causing the lubricating oil 3 to leak out.

[0024] The present invention is not limited to the above-described embodiment. The acceleration described in the present invention may be acceleration due to a change in the moving speed, or acceleration due to gravitational acceleration caused by tilting relative to a horizontal plane. The number of outlets in the present invention is not limited to two, but may be three or more. Their locations are not limited to symmetrical positions relative to the center of the oil tank or the upper plate. Any suitable configuration may be adopted for the valve mechanism and valve control unit as long as they perform the intended operation of the present invention. [Explanation of symbols]

[0025] 1 engine 2 Oil pan 3 Lubricating oil 3a Oil level 4 Oil Tank 5. Scavenge Pump 6. Supply pump 7 Intake system 8 Circulation channel 9 Upper plate 10a,10b outlet 11 Valve mechanism 12a, 12b shutter 13 Arm 14 Rotation axis 15 Valve control section

Claims

[Claim 1] An oil tank of a dry sump lubrication system that stores lubricating oil pumped from an oil pan, delivers the lubricating oil to predetermined locations that require lubrication, and discharges gas separated from the lubricating oil, a plurality of exhaust ports for exhausting the gas, the exhaust ports being provided in an upper plate portion that closes the upper end portion; a valve mechanism that opens and closes the outlet; a valve control unit that operates based on acceleration to operate the valve mechanism; Equipped with The valve control unit is configured to operate the valve mechanism in a state in which the discharge port located on the side where the oil level of the lubricating oil increases due to the acceleration is closed and the discharge port located on the side where the oil level decreases due to the acceleration is opened. An oil tank for a dry sump lubrication system.

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