JP7614903B2 - Scavenge Pump - Google Patents

Description

The present invention relates to a scavenge pump that pumps oil from a catch tank, which collects oil supplied to parts, to an oil pan where the oil is stored.

Some vehicles are equipped with components such as turbochargers. These components are lubricated and cooled by the oil circulating inside the vehicle. The oil that passes through the components is collected by a catch tank and returned from the catch tank to the oil pan. At this time, if the catch tank is located at a lower position than the oil pan, a scavenge pump is used to pump the oil from the catch tank to the oil pan. Prior art related to scavenge pumps is disclosed in Patent Document 1.

Patent Document 1 explains the characteristics of a scavenge pump by comparing it with a feed pump for circulating oil. One of the characteristics is that a feed pump transports almost only oil, whereas a scavenge pump transports not only oil but also air.

JP 2019-78190 A

For example, immediately after starting the vehicle, there may not be enough oil circulating in the scavenge pump, and very little oil may be filled in it. Even if the scavenge pump operates in this situation, a lot of air will be trapped between the gears that pump the oil. If there is insufficient oil filled in the scavenge pump, the sealing performance will be poor, making it difficult to pump up a sufficient amount of oil. For this reason, there is room for improvement in terms of circulating oil efficiently.

The objective of the present invention is to provide a scavenge pump that can circulate oil efficiently.

According to the present invention, the oil pump is used to pump oil from a catch tank that collects oil supplied to a component to an oil pan in which the oil is stored,
The oil pump has a gear for pumping oil and a housing for accommodating the gear.
The housing has an oil receiving portion formed on its outer surface capable of receiving oil sprayed from the outside, and an oil inlet hole is provided in a position that is continuous with the lower part of the oil receiving portion and faces the gear, for introducing oil sprayed into the oil receiving portion. This scavenge pump is provided.

The present invention provides a scavenge pump that can circulate oil efficiently.

1 is a schematic diagram of an oil circulation system in which a scavenge pump according to an embodiment of the present invention is used; FIG. 2 is a perspective view of the scavenge pump shown in FIG. 1 . FIG. 3 is an exploded view of the scavenge pump shown in FIG. 2. FIG. 4A is a diagram for explaining the operation of a scavenge pump according to a comparative example, and FIG. 4B is a diagram for explaining the operation of a scavenge pump according to an embodiment.

The embodiment of the present invention will be described below with reference to the attached drawings. In the drawings, Up indicates top and Dn indicates bottom.

<Example>
1, for example, a vehicle is equipped with an oil circulation device 10 for circulating oil. A scavenge pump 20 according to the present invention constitutes a part of the oil circulation device 10.

The oil circulation device 10 has an oil pan 11 in which oil Oi is stored, a feed pump 12 capable of pumping the oil Oi from the oil pan 11, a catch tank 14 that collects the oil Oi sent from the feed pump 12 to the turbocharger 13 and used to cool the turbocharger 13, a scavenge pump 20 that pumps the oil Oi from the catch tank 14 to the oil pan 11, and a nozzle 16 capable of injecting the oil Oi into the scavenge pump 20.

The flow path of the oil circulation device 10 branches out to lubricate and cool various components other than the turbocharger 13. The oil Oi that has passed through the other components is also returned to the oil pan 11.

Here, in addition to the engine, components that are lubricated and cooled by oil Oi include the turbocharger 13 and super turbocharger. In this embodiment, the turbocharger 13 as a supercharger will be used as an example of a component that is lubricated and cooled by oil. For convenience, the turbocharger 13 will be referred to as "component 13."

Refer to FIG. 2. The nozzle 16 is provided facing the scavenge pump 20. For example, when the scavenge pump 20 is operated, oil Oi is sprayed from the nozzle 16 toward the scavenge pump 20. The reason for this will be described later.

See also Figure 3. The scavenge pump 20 is configured by housing a rotatable inner rotor 22 in a housing 30 and an outer rotor 23 that surrounds the inner rotor 22 and rotates as the inner rotor 22 rotates.

The housing 30 has a main body 31 in which the inner rotor 22 and the outer rotor 23 are housed, and a lid 32 that is placed on top of the main body 31.

The main body 31 has an intake hole 31a that is opened to draw in oil from the outside, an intake port 31b that leads from the intake hole 31a to the inner rotor 22 and the outer rotor 23, a discharge port 31c to which the oil drawn in from the intake port 31b is transported, and a discharge hole 31d that is opened to discharge the oil transported to the discharge port 31c to the outside.

An oil receiving portion 32b capable of receiving oil sprayed from the nozzle 16 is formed on the outer peripheral surface of the lid portion 32, and is recessed from the general surface 32a toward the side surfaces of the inner rotor 22 and the outer rotor 23. An oil introduction hole 32c is also formed in a position that is continuous with the lower portion of the oil receiving portion 32b and overlaps with the boundary between the inner rotor 22 and the outer rotor 23.

The general surface 32a and the oil receiving portion 32b are connected by a guide portion 32d that guides the oil Oi to the oil introduction hole 32c. The guide portion 32d is formed continuously along the outer periphery of the oil receiving portion 32b and the edge of the oil introduction hole 32c.

The oil receiving portion 32b is formed so that its width gradually narrows toward the oil introduction hole 32c formed below. In addition, the vertical length of the oil receiving portion 32b is longer than the diameter of the oil introduction hole 32c, which is formed in a cylindrical shape. The area of the oil receiving portion 32b is larger than the area of the oil introduction hole 32c.

The oil introduction hole 32c is a hole that is opened to introduce the oil Oi injected into the oil receiving portion 32b into the inside of the housing 30. The oil introduction hole 32c is formed at a position that overlaps with the boundary portion between the inner rotor 22 and the outer rotor 23.

See FIG. 4B. For example, the oil introduction hole 32c expands in diameter from the outer peripheral surface toward the inner peripheral surface. That is, the diameter of the oil introduction hole 32c is larger on the inner peripheral surface side than on the outer peripheral surface side.

The oil introduction hole 32c may be formed at a position above the boundary between the inner rotor 22 and the outer rotor 23.

The oil introduction hole 32c may have the same diameter from the outer peripheral surface side to the inner peripheral surface side. The oil introduction hole 32c may have the same diameter from the outer peripheral surface side to the inner peripheral surface side and may be formed with a downward slope toward the inner peripheral surface side.

An oil reservoir 32e capable of storing oil Oi together with the guide portion 32d is provided along the lower portion of the guide portion 32d and below the oil introduction hole 32c. The oil reservoir 32e is formed in a substantially semicircular shape along the edge of the lower half of the oil guide portion 32d. It is preferable that the upper surface of the oil reservoir 32e is higher than the lower edge of the outer surface side of the oil introduction hole 32c.

In addition, the oil reservoir 32e can be formed integrally with the general surface 32a rather than being a separate member.

A rod-shaped shaft member passes through the center of the inner rotor 22. The shaft member is connected, for example, to the crankshaft of the engine. In this case, when the engine is running, the crankshaft rotates, and the inner rotor 22 also rotates. The outer rotor 23, which is disposed on the outer periphery of the inner rotor 22, rotates as the inner rotor 22 rotates.

The inner rotor 22 and the outer rotor 23 are gears that pump oil by rotating. Hereinafter, the inner rotor 22 and the outer rotor 23 may be collectively referred to as "gears 22, 23."

Refer to Figures 1 and 3. As the gears 22 and 23 rotate, oil Oi is pumped up from the catch tank 14. The pumped up oil Oi flows from the suction hole 31a to the suction port 31b. The oil Oi is sucked into the space surrounded by the inner rotor 22 and the outer rotor 23 from the suction port 31b. The sucked oil Oi is discharged to the discharge port 31c as the space surrounded by the inner rotor 22 and the outer rotor 23 becomes smaller. The oil Oi discharged to the discharge port 31c is discharged from the discharge hole 31d to the outside of the housing 30 and returned to the oil pan 11.

However, immediately after starting the vehicle, the oil Oi is not yet sufficiently circulated, and the oil Oi in the scavenge pump 20 may have almost fallen, and the sealing in the scavenge pump 20 may be insufficient. Even if the scavenge pump 20 operates in such a situation, a lot of air will be contained between the inner rotor 22 and the outer rotor 23. If the sealing between the inner rotor 22 and the outer rotor 23 is poor, the force to suck up the oil Oi is weak, making it difficult to circulate a sufficient amount of oil Oi. For this reason, the oil Oi is injected from the nozzle 16 and supplied to the inside of the housing 30. The injected oil Oi is supplied to the inside of the housing 30, thereby improving the sealing between the inner rotor 22 and the outer rotor 23. This allows the oil Oi accumulated in the catch tank 14 to be sufficiently pumped up. In other words, the oil Oi injected from the nozzle 16 plays the role of priming water.

The nozzle 16 starts injecting oil immediately after the engine starts rotating, or after a time lag of a few seconds. As long as the engine continues to rotate, the oil Oi continues to be sprayed from the nozzle 16. At this time, the pressure of the oil sprayed from the nozzle 16 changes depending on the engine speed. When the engine speed is high, the oil is sprayed at high pressure.

The scavenge pump 20 described above is summarized below.

The scavenge pump 20 is used to pump oil Oi from a catch tank 14 that collects oil Oi supplied to the parts 13 to an oil pan 11 in which the oil Oi is stored. The scavenge pump 20 also has gears 22, 23 for pumping up the oil Oi, and a housing 30 that houses these gears 22, 23. The housing 30 has an oil receiving portion 32b formed on its outer periphery that can receive oil Oi sprayed from the outside, and an oil introduction hole 32c is opened at a position that is continuous with the lower part of the oil receiving portion 32b and faces the gears 22, 23, for introducing the oil Oi sprayed into the oil receiving portion 32b into the inside.

The oil introduction hole 32c is provided in the housing 30, so that oil Oi sprayed from the outside toward the housing 30 can be introduced. Some of the oil Oi introduced into the housing 30 flows between the gears 22 and 23, improving the sealing performance of the gears 22 and 23. This allows the oil Oi to be pumped up efficiently. In other words, the scavenge pump 20 can circulate the oil Oi efficiently.

The reason for forming the oil receiving portion 32b on the housing 30 will now be explained.

Refer to FIG. 4A. The inventors first created a scavenge pump 120 in which only the oil introduction hole 132c was formed in the housing 130. Although such a scavenge pump 120 was able to circulate oil efficiently, there was room for improvement in terms of circulating oil more efficiently. As a result of research, the inventors found that the oil Oi injected from the nozzle 116 was injected directly onto the gears 122 and 123, causing the gears 122 and 123 to slightly displace, causing the flow rate of the oil to be pumped to deteriorate. In addition, even if the oil Oi does not directly hit the gears 122 and 123, the pressure of the injected oil Oi can block the discharge side flow path such as the discharge hole portion 31d, causing the oil Oi to become clogged, resulting in a deterioration in the flow rate of the oil to be pumped.

Refer to FIG. 4B. The inventors formed an oil receiving portion 32b capable of receiving the oil Oi sprayed from the nozzle 16 on the outer peripheral surface of the housing 30, and formed an oil introduction hole 32c for introducing the oil Oi sprayed into the oil receiving portion 32b into the inside of the housing 30 continuously at the lower part of the oil receiving portion 32b. The oil Oi is sprayed from the nozzle 16 into the oil receiving portion 32b, and reaches the oil introduction hole 32c along the oil receiving portion 32b. The oil that reaches the oil introduction hole 32c passes through the oil introduction hole 32c and reaches the inside of the housing 30. As a result, the oil Oi flows slowly into the inside of the housing 30. In this scavenge pump 20, the circulating oil flow rate can be increased compared to the scavenge pump 120 (see FIG. 4A) according to the comparative example. In other words, the scavenge pump 20 can circulate the oil Oi more efficiently.

In addition, a guide portion 32d for guiding the oil Oi to the oil inlet hole 32c is formed along the edge on the outer peripheral surface side of the oil inlet hole 32c. The guide portion 32d allows the oil Oi to be guided to the oil inlet hole 32c. This allows the oil Oi sprayed into the oil receiving portion 32b to be guided further inside the housing 30, ensuring the sealing performance of the gears 22 and 23. This allows the oil Oi to circulate more efficiently.

See Figure 3. The area of the oil receiving portion 32b is larger than the area of the oil introduction hole 32c. This allows the injected oil to be received more reliably by the oil receiving portion 32b, and also prevents the oil from being injected directly into the oil introduction hole 32c. This allows the oil Oi to circulate more efficiently.

See FIG. 4B. In the housing 30, an oil reservoir 32e is formed that can store oil at the bottom of the oil introduction hole 32c together with the guide portion 32d. By forming the oil reservoir 32e, the oil Oi that has flowed down along the oil receiving portion 32b can be more reliably introduced into the oil introduction hole 32c. The guide portion 32d may be flat, or may be formed with a downward slope toward the oil introduction hole 32c.

The oil introduction hole 32c also expands in diameter from the outer circumferential surface toward the inner circumferential surface. For example, when a vehicle is stopped on a slope, the scavenge pump 10 may tilt relative to the horizontal axis. With this configuration, even if the scavenge pump 10 is tilted, the oil Oi that hits the oil receiving portion 32b can be reliably introduced into the pump.

See Figure 3. The oil receiving portion 32b is formed so that its width gradually narrows toward the oil introduction hole 32c. This allows more oil to be received by the oil receiving portion 32b, and the received oil can be more reliably guided to the oil introduction hole 32c. This allows the oil Oi to circulate more efficiently.

The oil pan 11 (see FIG. 1) is generally always filled with a certain amount of oil. Therefore, in the feed pump 12 that draws oil from the oil pan 11, the sealability between the gears is maintained to a certain degree. In other words, the problem of poor sealability between the gears 22, 23 in certain cases, as with the scavenge pump 20, is unlikely to arise in the first place. In this respect, the feed pump 12 and the scavenge pump 20 are significantly different.

The scavenge pump of the present invention has been described using an example of application to a vehicle, but it can also be applied to vehicles other than vehicles, construction machinery, etc., and is not limited to these types. Also, although the scavenge pump has been described using an internal gear pump as an example, the present invention can also be applied to an external gear pump.

In other words, as long as the action and effect of the present invention are achieved, the present invention is not limited to the examples.

The scavenge pump of the present invention is suitable for pumping vehicle cooling oil to the oil pan.

11...Oil pan 13...Turbocharger (parts)
14... catch tank 20... scavenge pump 22... inner rotor (gear)
23...Outer rotor (gear)
30: Housing; 32b: Oil receiving portion; 32c: Oil introduction hole; 32d: Guide portion; 32e: Oil reservoir portion; Oi: Oil

Claims (6)

It is used to pump oil from the catch tank that collects the oil supplied to the parts to the oil pan where the oil is stored.
The oil pump has two gears that mesh with each other to pump oil, and a housing that houses the gears;
an oil receiving portion capable of receiving oil injected from the outside is formed on an outer peripheral surface of the housing, and an oil introduction hole is formed in a position continuous with a lower portion of the oil receiving portion and facing the gear, for introducing the oil injected into the oil receiving portion into the inside of the housing ;
The oil receiving portion is formed at a position overlapping a side surface of the gear,
A scavenge pump , wherein the oil inlet hole faces the interface between the two gears . The scavenge pump according to claim 1, wherein a guide portion for guiding oil to the oil inlet hole is formed along the edge of the outer peripheral surface of the oil inlet hole. The scavenge pump according to claim 1 or 2, wherein the area of the oil receiving portion is larger than the area of the oil introduction hole. The scavenge pump according to claim 2, wherein the housing has an oil reservoir capable of storing oil around the periphery of the oil introduction hole together with the guide portion. The scavenge pump according to any one of claims 1 to 4, wherein the oil introduction hole expands in diameter from the outer peripheral surface toward the inner peripheral surface. The scavenge pump according to any one of claims 1 to 5, wherein the oil receiving portion is formed so that its width gradually narrows toward the oil introduction hole.

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