Patent Application
20200277952
The present disclosure relates to pumps, specifically to positive-displacement pumps for use in automotive vehicles.
A pump is a device that raises, transfers, delivers, or compresses fluids by suction or pressure of both. Vehicles may employ one or more pumps that provide fluid e.g., coolant or oil to a desired component within the vehicle. Mechanically driven pumps are generally coupled to and powered by internal combustion engine. Powering a pump by an electric motor decreases the load or work required from the engine, thus increasing the efficiency of the engine.
A positive displacement pump is a pump that displaces a known volume of fluid per unit cycle. One category of a positive displacement pump is a gear pump that includes two or more gears that are disposed within a pump housing. The gears may be rotatably coupled to an end plate that extends between an outer wall of the housing. The gears are arranged so that the teeth of each of the gears trap and displace fluid to create a low-pressure area, near an inlet of the pump, and a high-pressure area, near the discharge of the pump.
According to one embodiment, an external gear pump is provided. The external gear pump may include a housing, a first gear, a second gear, and an end plate. The housing may include a peripheral wall forming an enclosure and defining an inlet and a discharge port. The first gear may include a first tooth and a second tooth. The second gear may be disposed within the housing and include a third tooth that engages the first tooth and the second tooth to form a pressure pocket. The end plate may be disposed within the housing. The first gear and the second gear may each be rotatably coupled to the end plate. The end plate may define a discharge channel and a bridge portion. The discharge channel may extend between the discharge port and the bridge portion. The bridge portion may define a relief portion and the relief portion may be configured such that fluid is communicated from the pressure pocket to the discharge port.
The relief portion may be at least partially defined by an axial surface by one of the teeth.
The relief portion may be comprised of a plurality of recessed finger cuts.
In one or more embodiments, when the first gear and the second gear are arranged in a first relative position, a first recessed finger cut of the plurality of recessed finger cuts may be partially eclipsed by the pressure pocket in an axial direction of the first and second gears.
The second gear may be provided with a fourth tooth, and when the first gear and the second gear are arranged in the first relative position, the third tooth, the fourth tooth, and the first tooth may define a second pressure pocket. A second recessed finger cut of the plurality of recessed finger cuts may at least partially eclipse the second pressure pocket in the axial direction of the first and second gears.
In one or more embodiments, when the first gear and the second gear are arranged in a second relative position, the first tooth, the second tooth, and the third tooth may define a third pressure pocket. A third recessed finger cut of the plurality of recessed finger cuts may at least partially eclipse the third pressure pocket in the axial direction of the first and second gears.
The second gear may be provided with a fifth tooth. When the first gear and the second gear are arranged in a second relative position, the second tooth, the third tooth, and the fifth tooth may define a fourth pressure pocket. A fourth finger cut of the plurality of recessed finger cuts may least partially eclipse the fourth pressure pocket in the axial direction of the first and second gears.
According to another embodiment, an external gear pump is provided. The external gear pump may include a peripheral wall that may form an enclosure and define an inlet and a discharge port. The gear pump may also include an end plate that may be disposed within the housing and the end plate may define a first recessed area. a second recessed area, and a bridge portion. The bridge portion may be disposed between a discharge channel and an inlet channel, that may each be defined by the second recessed area. The pump may include a first gear, that may include a first tooth and a second tooth, disposed within the first recessed area and configured to rotate about a first rotational axis. The pump may also include a second gear, disposed within the second recessed area and configured to rotate about a second rotational axis. The second gear may include a third tooth. When the first gear and the second gear are arranged in a first relative position, the third tooth may engage the first tooth and the second tooth to form a pressure pocket. The bridge may define a relief portion that may be configured to communicate fluid from the pressure pocket to the discharge port.
According to yet another embodiment, a gear pump is provided. The gear pump may include a housing that may include a peripheral wall forming an enclosure and defining an inlet and a discharge port. An end plate may be disposed within the housing and define a first recessed area, a second recessed area, and a bridge portion. The bridge portion may be disposed between a discharge channel and an inlet channel, each defined by the second recessed area. And the bridge portion may define a first recessed notch. The pump may also include a first gear, including a plurality of first gear teeth, disposed within the first recessed area and configured to rotate about a first rotational axis, and a second gear including a plurality of second gear teeth, disposed within the second recessed area and configured to rotate about a second rotational axis. When the first gear and the second gear are arranged in a first relative position, a first pair of teeth of the plurality of first gear teeth engages a first tooth of the plurality of second gear teeth to form a first pressure pocket. when the first gear and the second gear are arranged in a second relative position, a second pair of teeth of the plurality of first gear teeth engages a second tooth of the plurality of second gear teeth to form a second pressure pocket, and wherein the first recessed notch is positioned such that when the first gear and the second gear are arranged in either the first relative position or the second relative position, the first recessed notch is at least partially eclipsed by either the first pressure pocket or the second pressure pocket, respectively.
Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
The terms “first,” “second,” “third” etc. are merely exemplary and do not indicate a specific order. Rather, the terms “first,” “second,” “third” etc. are used to identify and distinguish one element from another.
The term “substantially” or “about” may be used herein to describe disclosed or claimed embodiments. The term “substantially” or “about” may modify a value or relative characteristic disclosed or claimed in the present disclosure. In such instances, “substantially” or “about” may signify that the value or relative characteristic it modifies is within ±0%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5% or 10% of the value or relative characteristic.
As fluid enters from the inlet 14 of the housing 12 the fluid is trapped between the teeth positioned nearest to the inlet and an inner surface e.g., 127a of the outer wall of the housing 12. Because the fluid is trapped between the teeth and the inner surface of the outer wall, the fluid is carried around the outside of the gears towards the discharge of the pump. The high-pressure area within the housing is formed by the fluid disposed between the discharge 16 of the pump and the gear teeth. The teeth of each of the gears 22a, 18, and 22b are sized and arranged to create a seal between the faces of each of the teeth that are engaged with one another. While some fluid may seep between the end plate and the gears, or the cover and the gears, or both, the seal prevents fluid from seeping from the high-pressure side to the lower pressure side.
A transverse axis TA may extend between rotational axes of each of the gears. A portion of the pump 10 located above the transverse axis TA may be referred to as the outlet side or high-pressure side of the pump 10 and a portion of the pump 10 located below the transverse axis TA may be referred to as the inlet side or low-pressure side of the pump 10.
As will be described in greater detail below, the seal created by the arrangement of the teeth may prevent fluid seeping from the high-pressure side to the lower pressure side, the gear teeth may form pockets that may contain or trap fluid as the gears rotate. The rotation of the gears may compress the fluid and increase fluid pressure within the pocket, creating a “pressure pocket.” The increase in pressure within the pressure pocket, may increase the torque required to rotate the gears. And this increase in torque may decrease the efficiency of the pump.
Referring to
The arrangement and geometry of the first gear 18, the second gear 22b, and the portion of the end plate 124 adjacent to the first are symmetrically opposite e.g., mirrored, to the arrangement and geometry of the first gear 18, the third gear 22a, and the adjacent portion of the end plate 124. As such, the description of the first gear 18, the third gear 22a, and the adjacent portion of the end plate 124, illustrated in
A first discharge channel 132b, may be defined by the end plate 124 and extend between the discharge port 16 and a first bridge portion 131b. A first inlet channel 130b may be defined by the end plate 124 and extend between an inlet port 14 and the first bridge portion 131b. The bridge portion 131b may define one or more relief portions e.g., 152a, 152b, 150a, 150b, 156a, 156b, 158a, and 158b, that may be configured to route fluid from a pressure pocket, formed by the gear teeth, to the discharge port 16.
In one or more embodiments, the bridge portions 131a, 131b may be referred to as a “bridge.” Also, the relief portions may be referred to as a plurality of recessed finger cuts or as a plurality of recessed notches.
Referring specifically to
When the first gear 18 and the second gear 22b are arranged in the first relative position, the first tooth 182 and the second tooth 188 of the first gear 18 may engage the third tooth 170 of the second gear 22b to form a first pressure pocket 193. The first recessed finger cut 152b defined by the bridge portion 131b is positioned so that the first pressure pocket 193 eclipses the first recessed finger cut 152b. The first recessed finger cut 152b may allow fluid to move from the first pressure pocket 193 to the outlet channel 132b (
The first pressure pocket may be bound by a first face 190 of the second tooth 188, the second face 186 of the first tooth, a root portion of the first gear 18 extending therebetween, and a second face 174 of the third tooth 170.
The second gear 22b may be provided with a fourth tooth 176 that engages the first tooth 182 of the first gear 18, when the first gear 18 and the second gear 22b are in the first relative position. The third tooth 170 and the fourth tooth 176 of the second gear 22b engages the first tooth 182 to form a second pressure pocket 194. The bridge portion 131b may define a second recessed finger cut 158b. The second recessed finger cut 158b may be positioned so that the second pressure pocket 194 is eclipses the second recessed finger cut 158b. The second recessed finger cut 158b may allow fluid to flow from the second pressure pocket 194 to the inlet cooling channel 130b (
The fourth gear may include a first face 178 and a second face 180. The second pressure pocket may bound by a root portion of the second gear 22b that extends between the first face 178 of the fourth tooth 176 and the second face 174 of the third tooth 170.
The bridge portion 131b may include a third recessed finger cut 150b that may be connected to the first recessed finger cut 152b by an intermediate portion 164. The bridge portion may also include a fourth recessed finger cut 156b that is connected to the third recessed finger cut 158b by a second intermediate portion 166.
Referring to
The second gear 22b may include a fifth tooth 198. The fifth tooth 198 and the third tooth 170 may each engage the second tooth 188 to form a third pressure pocket 200. When the gears 18, 22b are in the second relative position, the third pressure pocket 200 may substantially eclipse the third recessed finger cut 150b. The third recessed finger cut may provide the same function described above with respect to the first recessed finger cut 152b.
In the second relative position, the first tooth 182 and the second tooth 188 may engage the third tooth 170 to form a fourth pressure pocket 202. When the gears 18, 22b are in the second relative position, the fourth pressure pocket 202 may substantially eclipse the fourth recessed finger cut 156b. The fourth recessed finger cut 156b may provide the same function described above with respect to the second recessed finger cut 158b.
Referring to
The first gear 18 may include a sixth tooth 196. The sixth tooth 196 and the second tooth 188 may engage the fifth tooth 198 of the second gear 22b to form a fifth pressure pocket 204. When the gears 18, 22b are in the third relative position, the fifth pressure pocket 204 may substantially eclipse the first recessed finger cut 152b. In the third relative position, the fifth tooth 198 and the third tooth 170 may engage the second tooth 188 to form a sixth pressure pocket 206. The sixth pressure pocket 206 may substantially eclipse the second recessed finger cut 158b.
Referring to
The bridge portion 131b may be divided into an upper portion and a lower portion. The upper portion may be the portion that is disposed above the transverse axis TA and the lower portion of the bridge portion 131b may be disposed below the transverse axis TA. The upper portion of the bridge portion 131b may define the first recessed finger cut 152b and the third recessed finger cut 150b. The lower portion of the bridge portion may define the second recessed finger cut 158b and the fourth recessed finger cut 156b. The first intermediary portion 164 may be spaced apart from the transverse axis TA by a first height H1 and the second intermediary portion 166 may be spaced apart from the transverse axis TA by a first height H2. In one or more embodiments, the second height H2 may be greater than the first height H1. The first intermediary portion 164 may define a second length L2, measured from end points of the first recessed finger cut 152b and the third finger cut 150b. The second intermediary portion 166 may define a third length L3, measured from end points of the fourth recessed finger cut 156b and the second finger cut 158b. In one or more embodiments, the second length L2 may be greater than the third length L3.
An end portion of the third recessed finger cut 150b may be spaced apart from the second rotational axis RA2 by a fourth length L4 and an end portion of the second recessed finger cut 158b may also be spaced apart from the second rotational axis RA2 by a fifth length L5. In one or more embodiments, the fourth length L4 may be greater than the fifth length L5. An end portion of the fourth recessed finger cut 156b may be spaced apart from the first rotational axis RA1 by a sixth length L6 and an end portion of the first recessed finger cut 152b may be spaced apart from the first rotational axis RA1 by a seventh length L7. In one or more embodiments, the sixth length L6 may be less than the seventh length L7.
The first recessed finger cut 152b may define a first radius R1 and the third recessed finger cut 150b may define a third radius R3. In one or more embodiments, the first radius R1 may be larger than the third radius R3. The radii of the first recessed finger cut 152b and the third recessed finger cut 150b may be sized to receive a sufficient volume of fluid to decrease the pressure of the respective pressure pockets. However, increasing the radii may beyond a predetermined threshold may decrease the amount of fluid moved by the gear teeth, thereby decreasing the efficiency of the pump assembly 10. The second recessed finger cut 158b may define a second radius R2 and the fourth recessed finger cut 156b may define a fourth radius R4. In one or more embodiments, the second radius R2 may be greater than the fourth radius R4.
In one or more embodiments, the end plate 124 may be integrally formed e.g., one piece, to the pump housing 12.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.
The following is a list of reference numbers shown in the Figures. However, it should be understood that the use of these terms is for illustrative purposes only with respect to one embodiment. And, use of reference numbers correlating a certain term that is both illustrated in the Figures and present in the claims is not intended to limit the claims to only cover the illustrated embodiment.
