JP2022534048A - Variable displacement lubricating oil pump - Google Patents

Abstract

The present invention relates to a variable displacement lubricating oil pump (10) for supplying pressurized lubricating oil. The variable displacement lubricating oil pump (10) includes a fixed pump housing (14) and a displaceable control ring disposed within the pump housing (14) and radially confining a generally cylindrical pump chamber (20). (16), an outlet chamber (28) partially bounded by the radially outer side of the control ring (16), and an outlet chamber (28) adjacent to the control ring (16) within the pump housing (14). A displaceably supporting slide bearing (42) is provided, the slide bearing (42) being defined by the pump housing and having a first slide bearing surface (44) extending in the slide plane (P) and a control ring ( 16) and a second slide bearing surface (46) defined by . The outer projected area (A1) defined by the orthographic projection of the outer pressure surface (30) of the control ring (16) onto the slide plane (P) is the inner pressure surface of the control ring (16) onto the slide plane (p). Because it is small compared to the maximum inner projected area (A2-max) defined by the orthographic projection of (40), the variable displacement lubricating oil pump (10) according to the present invention can be realized cost-effectively, and Reliable and efficient pump operation is possible. [Selection drawing] Fig. 2

Description

The present invention relates to variable displacement lubricating oil pumps for supplying pressurized lubricating oil, in particular to mechanical variable displacement lubricating oil pumps for supplying pressurized lubricating oil for internal combustion engines.

The lubricating oil pump is mechanically driven by the engine, for example via gears or belts, and is fluidly connected to the engine to inject pressurized lubricating oil into the engine. The variable displacement of the lube pump makes it possible to control and stabilize the pump discharge pressure of the lube pump, thereby for example controlling and stabilizing the lube oil pressure in the gallery in the engine. is realized.

WO2018/196991 discloses a typical variable displacement lubricating oil pump for providing pressurized lubricating oil for internal combustion engines. A typical lubricating oil pump includes a stationary pump housing and a displaceable control ring disposed within the pump housing and radially retaining a generally cylindrical pump chamber. The lubricating oil pump is also provided with an outlet chamber partially bounded by the radially outer side of the control ring and a rotatable pump rotor disposed within the pump chamber. A pump porter is provided with a plurality of rotor vanes that define a plurality of pump chambers. The rotor vanes rotate within the displaceable control ring, with which the pump chamber rotates as well. Additionally, the lubricating oil pump has a pump chamber pressure section defined by a pump chamber chamber in fluid communication with the outlet chamber through the discharge opening, and adjacent the outlet chamber and displaceably supporting a control ring within the pump housing. It has slide bearings. The slide bearing is defined by the pump housing and includes a first slide bearing surface extending within the slide surface and a second slide bearing surface defined by the control ring.

International Publication No. 2018/196991

Due to the shape of the outlet chamber of the lubricating oil pump, when the outlet chamber is filled with pressurized lubricating oil, the control ring is pushed away from the outlet chamber and towards the pump inlet. As a result, the second bearing surface defined by the control ring moves away from the first bearing surface defined by the pump housing, creating significant bearing clearance. This gap in the bearing can provide a leakage path for lubricant from, for example, the outlet chamber to the control chamber located on the opposite side of the slide bearing. Unnecessary lubricant leakage into the control chamber can adversely affect the control of the position of the control ring, resulting in loss of pump discharge pressure control and pump performance.

A sealing portion is provided in the first slide bearing to prevent leakage of lubricating oil through the clearance of the bearing. However, the seals increase the sliding friction of the friction bearings, resulting in reduced pump efficiency. Furthermore, in order to prevent the seal from slipping out of the bearing gap, the pump housing and control ring must be provided with specific retaining means to hold the seal in place.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a variable displacement lubrication pump that is cost effective, reliable and efficient.

The above object is achieved by a variable displacement lubricating oil pump having the features of claim 1 .

SUMMARY OF THE INVENTION A variable displacement lubricating oil pump according to the present invention includes a pump housing defining a pump inlet and a pump outlet. Typically, the pump inlet is fluidly connected with the lubricating oil tank and the pump outlet is fluidly connected with the engine to supply pressurized lubricating oil to the engine.

The variable displacement lubricating oil pump according to the present invention also includes a control ring disposed within the pump housing and radially limiting the generally cylindrical pump chamber. Preferably, the control ring is linearly displaceable relative to the pump housing. In either case, the control ring is not pivotably hinged within the pump housing. Typically, the radial cross-section of the pump chamber is circular. Alternatively, the radial cross-section of the pump chamber may be non-circular, eg, slightly elliptical, to improve pump efficiency and pump pressure control.

Also, the variable displacement lubricating oil pump according to the present invention is provided with an outlet chamber fluidly connected with the pump outlet. The exit chamber is located directly adjacent to the control ring and partially bounded by the radially outer side of the control ring. During operation of the pump, the outlet chamber is filled with pressurized lubricating oil. The interface between the outlet chamber and the control ring, ie, the portion of the radially outer surface of the control ring that is in direct fluid contact with the outlet chamber, defines the outer pressure surface of the control ring.

The variable displacement lubricating oil pump according to the invention is also provided with a rotatable pump rotor which is arranged in the control ring, in particular in the pump chamber. The pump rotor includes a plurality of rotor vanes that define a plurality of pump chambers. Rotation of the rotor vanes within the control ring, with corresponding rotation of the pump chamber, injects lubricating oil from the inlet chamber into the outlet chamber. The pump rotor is mechanically driven by the engine, for example via a belt drive or gearing. Since the axis of rotation of the pump rotor is fixed, displacing the control ring changes the eccentricity of the pump rotor with respect to the surrounding control ring and consequently controls the displacement of the pump. In this way, the volume transition of the variable displacement lubricating oil pump is controlled.

Also, the variable displacement lubricating oil pump according to the present invention is defined by a pump chamber positioned adjacent to the discharge opening of the control ring and thus fluidly connected to the pump chamber via the discharge opening. A pump chamber pressure section is provided. During operation of the pump, the pump chamber pressure section is filled with pressurized lubricating oil. As the pump chamber rotates, the range of pump chamber pressure changes between the minimum and maximum ranges during pump operation. The interface between the pump chamber pressure portion and the control ring, ie, the radially inner portion of the control ring that is in direct fluid contact with the pump chamber pressure portion, defines the inner pressure surface of the control ring.

The variable displacement lubricating oil pump according to the present invention also includes at least one slide bearing positioned adjacent the outlet chamber and displaceably supporting the control ring within the pump housing. The slide bearing includes a first slide bearing surface and a corresponding second slide bearing surface. A first slide bearing surface is defined by the pump housing and extends in the slide plane. A second slide bearing surface is defined by the control ring and is provided opposite and parallel to the first slide bearing surface.

During operation of the pump, the pressure areas of the outlet chamber and the pump chamber are both filled with pressurized lubricating oil, so that the inner and outer pressure surfaces of the control ring are loaded with the same hydraulic pressure, in particular the hydraulic pressure of the pressurized lubricating oil. . As a result, the magnitude and direction of the total hydraulic load force generated by the lubricating oil pressure and affecting control is determined only by the shape of the pressure surface. Specifically, the magnitude and direction of the effective payload force perpendicular to the slide surface is determined by the proportion of the projected area defined by the orthographic projection of the pressure surface onto the slide surface.

According to the present invention, the control ring and the pump housing are such that the outer projected area defined by the orthographic projection of the outer pressure surface onto the slide surface is the maximum inner projected area defined by the orthographic projection of the inner pressure surface onto the slide surface. designed to be small compared to As a result, during operation of the pump, an effective hydraulic load force is generated perpendicular to the slide surface and towards the outlet chamber, forcing the second slide bearing surface of the control ring against the first slide bearing surface of the pump housing. This reduces the gap between the slide bearing surfaces, thereby preventing or at least significantly reducing lubricant leakage through the slide bearing without the need for a separate seal within the slide bearing. According to the variable displacement lubricating oil pump according to the present invention, the position of the control ring can be controlled reliably and efficiently. Also, since there is no need to provide seals in the slide bearings, the variable displacement lubricating oil pump according to the present invention can be realized very cost-effectively.

1 is a partial cross-sectional view of a variable displacement lubricating oil pump according to the present invention; FIG. 2 is an enlarged view of a portion of the lubricating oil pump of FIG. 1; FIG. Figure 2 is a schematic diagram of the orthographic area of the pressure surface of the control ring onto the slide surface in the lubricating oil pump of Figure 1;

In a preferred embodiment of the present invention, the projected area of the outer pressure surface onto the slide surface is small compared to the minimum projected area of the inner pressure surface onto the slide surface, so that the effective load force pressing against the slide bearing surface is occurs regardless of the rotational position of As a result, bearing clearances are minimized, resulting in a highly efficient and reliable lubricating oil pump.

The outer pressure surface preferably lies completely laterally on the outlet side of the centerline of the pump chamber, which extends parallel to the slide surface. Further, the outer pressure surface is preferably positioned within an angular range of 45° to 135° with respect to the center of the pump chamber and begins at the pump chamber centerline. An outer pressure surface configured in this way does not significantly affect the control of the position of the control ring, since the effective hydraulic load force is generated substantially perfectly perpendicular to the slide surface. The result is a reliable and efficient lubricating oil pump.

In a preferred embodiment of the present invention, a control chamber is provided for hydraulically controlling the position of the control ring. Typically, the control chamber is provided circumferentially adjacent to the outlet chamber on the front side of the control ring. Because the control chamber includes an interface with the control ring that extends substantially perpendicular to the slide surface, hydraulic pressure within the control chamber loads the control ring in a direction parallel to the slide surface. The control chamber largely surrounds the control ring in the circumferential direction and extends to the slide bearing so that the control chamber is fluidly separated from the outlet chamber only by the slide bearing. In this manner, the relatively large interface between the control ring and the control chamber allows relatively low hydraulic control chamber pressures to produce relatively high hydraulic actuating forces.

Embodiments of the present invention will be described with reference to the accompanying drawings.

1 and 2 show a variable displacement lubricating oil pump 10 for supplying pressurized lubricating oil to an internal combustion engine 12 . The lubricating oil pump 10 is provided with a stationary pump housing 14 , a displaceable control ring 16 and a rotatable pump rotor 18 . A control ring 16 is disposed within the pump housing 14 and radially confines a generally cylindrical pump chamber 20 .

Additionally, the lubricating oil pump 10 is provided with an inlet chamber 22 in fluid communication with a lubricating oil tank 24 and filled with lubricating oil at substantially atmospheric pressure during operation of the pump. Inlet chamber 22 is fluidly connected to pump chamber 20 by suction opening 26 in control ring 16 .

Additionally, the lubricating oil pump 10 is provided with an outlet chamber 28 in fluid communication with the engine 12 and filled with pressurized lubricating oil during operation of the pump. Outlet chamber 28 is located on the side of pump chamber 20 substantially opposite inlet chamber 22 and is partially limited by the radially outer side of control ring 16 . The interface between the outlet chamber 28 and the control ring 16 defines the outer pressure surface 30 of the control ring. The pressure face 30 lies entirely on the outlet side of the pump chamber 20 . In particular, the outer pressure surface 30 is located within the circular area S. The circular area S extends over an angular range of 45° to 135° with respect to the pump chamber center C and begins at the pump chamber centerline L which extends parallel to the slide plane P of the control ring 16 . Outlet chamber 28 is fluidly connected to pump chamber 20 by a discharge opening 31 in control ring 16 .

Additionally, the lubricating oil pump 10 is provided with a control chamber 32 circumferentially disposed between the inlet chamber 22 and the outlet chamber 28 on the front side of the control ring 16 . During operation of the pump, the control chamber 32 fills with lubricating oil. Controlling the lubricating oil pressure in the control chamber 32 allows hydraulic control of the position of the control ring 16 and, as a result, control of the pump displacement profile.

Furthermore, the lubricating oil pump 10 is provided with a slide bearing 42 that displaceably supports the control ring 16 within the pump housing 14 . A slide bearing 42 is positioned adjacent the outlet chamber 28 and the control chamber 32 to fluidly separate the control chamber 32 and the outlet chamber. The slide bearing 42 includes two slide bearing surfaces 44, 46 that contact each other. A first slide bearing surface 44 is defined by the pump housing 14 and a second slide bearing surface 46 is defined by the control ring 16 . The first slide bearing surface 44 extends in the slide plane P and the second slide bearing surface 46 is parallel to the first slide bearing surface 44 so that the control ring 16 is positioned within the slide plane P within the pump housing 14 . is displaced parallel to

Pump rotor 18 is disposed within pump chamber 20 and includes nine rotor vanes 33a-i that define nine pump chamber chambers 34a-i. During operation of the pump, rotor vanes 33a-i rotate within pump chamber 20, and pump chamber chambers 34a-i rotate accordingly. Lubricating oil is thereby injected from the inlet chamber 22 into the outlet chamber 28 . The pump rotor 18 is mechanically driven by the engine 12 , for example via a belt drive or gearing, so that it rotates at a rotational speed that is always directly proportional to the rotational speed of the engine 12 .

A pump chamber pressure portion 36 is defined by those of the pump chamber chambers 34a-i that are located adjacent to the discharge opening and are therefore fluidly connected to the outlet chamber 28 via the discharge opening 31. As shown in FIG. In the exemplary pump rotor position shown in FIG. 1, the pump chamber pressure section is defined by pump chamber chambers 34a-d. The interface between the pump chamber pressure portion 36 and the control ring 16 defines an inner pressure surface 40 of the control ring. As the pump rotor 18 rotates and with it the pump chambers 34a-i, the actual circumferential extent of the pump chamber pressure portion 36, and the inner pressure surface 40, varies from the minimum extent E1 during pump operation. It varies between the maximum range E2.

The orthographic projection of the outer pressure surface 30 onto the slide plane P defines an outer projected area A1. Depending on the current rotational position of the pump rotor 18, the orthographic projection of the inner pressure surface 40 onto the slide plane P defines a current inner projected area A2. The range of the current inner projected area A2 varies between the minimum inner projected area A2-min and the maximum inner projected area A2-max. FIG. 3 is a schematic diagram of the outer projected area A1 and the current inner projected area A2, as well as the minimum inner projected area A2-min and the maximum inner projected area A2-max at the exemplary rotor positions shown in FIGS. show. According to the present invention, the pump housing 14 and control ring 16 are designed such that the outer projected area A1 is small compared to the maximum inner projected area A2-max. Further, in this embodiment of the present invention, the outer projected area A1 is smaller than the minimum inner projected area A2-min.

During operation of the pump, the outlet chamber 28 and the pump chamber pressure section 36 are both filled with pressurized lubricant so that the outer pressure surface 30 and the inner pressure surface 40 are loaded with the same hydraulic pressure. Since the outer projected area A1 is less than the minimum inner projected area A2-min, the control ring 16 is forced with an effective effective load force F perpendicular to the slide plane P and toward the outlet chamber 28 during pump operation. Always hydraulically loaded. The second slide bearing surface 46 of the control ring 16 is constantly pressed against the first slide bearing surface 44 of the pump housing 14 during pump operation, resulting in a minimal clearance between the slide bearing surfaces 44,46. .

10 variable displacement lubricating oil pump 12 internal combustion engine 14 pump housing 16 control ring 18 pump rotor 20 pump chamber 22 inlet chamber 24 lubricating oil tank 26 suction opening 28 outlet chamber 30 outer pressure surface 31 discharge opening 32 control chamber 33a-i Rotor vane 34a-i pump chamber chamber 36 pump chamber pressure section 40 inner pressure surface 42 slide bearing 44 first slide bearing surface 46 second slide bearing surface A1 outer projected area A2 current inner projected area A2-min minimum inner projected area A2- max maximum inner projected area C center of pump chamber E1 minimum extent E2 maximum extent F effective load force L centerline of pump chamber P slide plane S circular area

Claims (5)

A variable displacement lubricating oil pump (10) for supplying pressurized lubricating oil, comprising:
The variable displacement lubricating oil pump (10)
a stationary pump housing (14);
a displaceable control ring (16);
an outlet chamber (28);
a rotatable pump rotor (18);
a pump chamber pressure section (36);
a slide bearing (42);
said control ring (16) is disposed within said pump housing (14) and radially bounds a generally cylindrical pump chamber (20);
said outlet chamber (28) is partially restricted by the radially outer side of said control ring (16);
an interface between said outlet chamber (28) and said control ring (16) defines an outer pressure surface (30) of said control ring (16);
said pump rotor (18) is disposed within said pump chamber (20) and comprises a plurality of rotor vanes (33a-i);
said rotor vanes (33a-i) define a plurality of pumping chambers (34a-i);
said pump chamber pressure portion (36) is defined by pump chamber chambers (34a-d) directly fluidly connected to said outlet chamber (28) through a discharge opening (31);
an interface between said pump chamber pressure portion (36) and said control ring (16) defines an inner pressure surface (40) of said control ring (16);
said slide bearing (42) adjoins said outlet chamber (28) and displaceably supports said control ring (16) within said pump housing (14);
The slide bearing (42) is
a first slide bearing surface (44) defined by said pump housing and extending in a slide plane (P);
a second slide bearing surface (46) defined by said control ring (16);
The outer projected area (A1) defined by the orthographic projection of the outer pressure surface (30) onto the slide surface (P) is defined by the orthographic projection of the inner pressure surface (40) onto the slide surface (p). smaller than the maximum medial projected area (A2-max)
A variable displacement lubricating oil pump (10) characterized by: the outer projected area (A1) is smaller than the minimum inner projected area (A2-min) defined by the orthographic projection of the inner pressure surface (40) onto the slide surface (p);
A variable displacement lubricating oil pump (10) according to claim 1, characterized in that: said outer pressure surface (30) is located entirely laterally on the outlet side of the centerline (L) of the pump chamber extending parallel to said slide surface (P);
A variable displacement lubrication pump (10) according to claim 1 or 2, characterized in that: said outer pressure surface (30) is positioned within an angular range of 45° to 135° with respect to the center (C) of said pump chamber, starting from the centerline (L) of said pump chamber;
A variable displacement lubricating oil pump (10) according to claim 3, characterized in that: a control chamber (32) is provided for hydraulically controlling the position of said control ring (16);
the slide bearing (42) fluidly separates the outlet chamber (28) and the control chamber (32);
A variable displacement lubrication pump (10) according to any one of claims 1 to 4, characterized in that:

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