Patent Description:
In conventional fluid pumps, internal components of the fluid pump are attached through various fasteners that attach typically stationary components to a housing of the pump. These stationary components can include various pump assemblies that are attached to an outer housing as well as various controllers and covers that are fixedly attached to the remainder of the housing. In a cartridge-style pump, the pump is inserted within an engine, transmission, or other fluid-handling mechanism for moving fluid from one location to another. The cartridge-style pump is typically in the form of a self-contained assembly that can be attached to an electrical system for the device and within some form of fluid or gaseous reservoir such that the pump can operate to move the material through the cartridge-style pump.

<CIT> discloses a rotary vane vacuum pump with at least one pump housing having an inner cylinder, which is framed in the axial direction by partitions, with a rotary piston arranged in the inner cylinder and provided with axially extending slides guided radially in slots, which is non-rotatably provided on a shaft that can be driven by a motor and which lies eccentrically in the inner cylinder, the motor being provided in a housing which accommodates the pump housing in a recess of a housing-like extension.

<CIT> discloses a pump unit has a pump housing with a pump housing opening, and a drive shaft for driving the pump unit. The drive shaft is arranged in the housing opening. A pump cover closes the housing opening in a fluid-tight manner. A radially circulating spring element, for example a disk spring and compression spring, axially lies at the pump cover. The spring element is designed such that the pump cover is pressed at the pump housing in an axial direction by the spring element. A retaining ring, for example a snap ring, fixes the spring element in the axial direction.

According to one aspect of the present invention, a fluid pump includes a stator. A rotor is rotationally operable with respect to the stator. A drive shaft extends from the rotor to a pump assembly that delivers a fluid from an inlet to an outlet. A pump housing includes an interior cavity that contains the stator, the rotor and the pump assembly. A pump cover is disposed at an end of the pump housing. The pump cover defines an end of the interior cavity. A spring assembly biases the pump cover in an axial direction toward the pump assembly.

According to another aspect of the present invention, a fluid pump includes a pump housing having an interior cavity. A pump element is positioned within the interior cavity and delivers a fluid from an inlet to an outlet. A pump cover defines an end of the interior cavity. A spring assembly axially biases the pump cover toward the pump element. The spring assembly, the pump cover and the pump element are retained within a perimeter retaining channel of the pump housing without the use of fasteners.

According to another aspect of the present invention, a fluid pump includes a pump housing having an interior cavity. A generated rotor is positioned within the interior cavity and delivers a fluid from an inlet to an outlet. A pump cover defines an end of the interior cavity. A pre-load ring-shaped spring axially biases the pump cover toward the generated rotor. A retaining ring is rotationally and axially fixed relative to the pump housing. The retaining ring, the pre-load ring-shaped spring and the pump cover are positioned within a perimeter retaining channel of the pump housing without the use of fasteners.

These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.

For purposes of description herein, the terms "upper," "lower," "right," "left," "rear," "front," "vertical," "horizontal," and derivatives thereof shall relate to the invention as oriented in <FIG>. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary.

As exemplified in <FIG>, reference numeral <NUM> generally refers to a fluid pump that includes a fastenerless assembly mechanism, whereby various components of the fluid pump <NUM> can be secured within a pump housing <NUM> without the use of external fasteners such as screws, bolts, and other similar fastening mechanisms. The fluid pump <NUM> can typically be in the form of a cartridge-style fluid pump <NUM> that is slidably installed within a fluid-handling assembly <NUM>, where the fluid pump <NUM> can be activated to move fluid, gas, or other fluid-type material from a reservoir to a separate location. According to various aspects of the device, the fluid pump <NUM> includes a stator <NUM> and a rotor <NUM> that is rotationally operable with respect to the stator <NUM>. A drive shaft <NUM> extends from the rotor <NUM> to a pump assembly <NUM>. A pump housing <NUM> includes an interior cavity <NUM> that contains the stator <NUM>, the rotor <NUM> and the pump assembly <NUM>. A pump cover <NUM> is disposed at an end <NUM> of the pump housing <NUM>, where the pump cover <NUM> defines an end <NUM> of the interior cavity <NUM> for the pump housing <NUM>. A spring assembly <NUM> is positioned and retained within a retaining channel <NUM> of the pump housing <NUM>. The spring assembly <NUM> serves to bias the pump cover <NUM> in a generally axial direction <NUM> toward the pump assembly <NUM> and along a rotational axis <NUM> of the drive shaft <NUM>. The pump cover <NUM> is slidably operable within the perimeter retaining channel <NUM> to absorb thermal expansion forces <NUM> as well as manufacturing tolerances that may be present within a series of manufactured pump housings <NUM>. The expansion forces <NUM> can result from thermal expansion as well as changes in the viscosity of the fluid being moved via the fluid pump <NUM>.

As exemplified in <FIG>, the fluid pump <NUM> can include a stator <NUM> that is overmolded by an overmold material <NUM> to form the pump housing <NUM>. The pump housing <NUM> can include a control side <NUM> that receives a printed circuit board (PCB) <NUM>, where the PCB <NUM> can include various controllers <NUM> for operating the fluid pump <NUM>. A PCB gasket <NUM> can be installed adjacent to the PCB <NUM> to provide a seal around the various electrical and processing components of the PCB <NUM>. A PCB cover <NUM> can also extend over the PCB <NUM> to engage the PCB gasket <NUM>. Various housing fasteners <NUM> can be disposed within the PCB cover <NUM> for fastening the PCB cover <NUM> to the pump housing <NUM>. The PCB cover <NUM> and the pump housing <NUM> can also cooperatively define various attachment apertures <NUM> that can be used to fasten the fluid pump <NUM> to the fluid-handling assembly <NUM> within which the fluid pump <NUM> operates.

Referring again to <FIG>, the pump housing <NUM> can also include a motor end <NUM>, where the stator <NUM> of the fluid pump <NUM> is overmolded within a portion of the pump housing <NUM>. The pump housing <NUM> can define an interior cavity <NUM> that defines a space for receiving the rotor <NUM> and the pump assembly <NUM>. For receiving the rotor <NUM>, the pump housing <NUM> can include a bearing plate <NUM> that includes a bearing assembly <NUM> against which the drive shaft <NUM> and the rotor <NUM> are held in place for rotational operation within the interior cavity <NUM> of the pump housing <NUM>. The rotor <NUM>, being in electromagnetic communication with the stator <NUM>, rotates within the interior cavity <NUM> when portions of the stator <NUM> are energized through the application of electrical current through the windings <NUM> of the stator <NUM>. The pump body <NUM> can include a pump sleeve <NUM> that extends around a portion of the drive shaft <NUM> and into a rotor channel <NUM> that is at least partially defined between the body <NUM> of the rotor <NUM> and the drive shaft <NUM>. The use of the pump sleeve <NUM> provides a locating feature and a support feature that extends around the drive shaft <NUM>. The pump sleeve <NUM> at least partially covers the drive shaft <NUM> and helps to support the drive shaft <NUM> within the interior cavity <NUM> of the pump housing <NUM>.

In order to maintain the position of the pump body <NUM> within the pump housing <NUM>, the pump housing <NUM> can include one or more alignment features <NUM> that are integrally formed within the material of the pump housing <NUM>. The pump body <NUM> typically includes an offset configuration and includes a pump receptacle <NUM> that receives a gerotor assembly <NUM>, such as a generated rotor. The pump receptacle <NUM> is typically positioned in an offset configuration within the pump body <NUM>. Because of this offset configuration, a specific rotational alignment of the pump body <NUM> within the pump housing <NUM> is desired. The use of the alignment feature <NUM> defined within the pump housing <NUM> provides this locating feature so that additional fasteners are not needed to locate the pump body <NUM> with respect to the pump housing <NUM>. The alignment features <NUM> defined within the pump housing <NUM> serve to rotationally align the pump body <NUM> with respect to the pump housing <NUM> and the drive shaft <NUM> of the rotor <NUM>.

The locating or alignment features <NUM> defined within the pump housing <NUM> also serve to align the pump cover <NUM> with respect to the pump housing <NUM>. Accordingly, the alignment features <NUM> of the pump housing <NUM> serve to rotationally align, or rotationally fix, the pump body <NUM>, the gerotor assembly <NUM> and the pump cover <NUM> within the pump housing <NUM>. This aligning configuration of the various components of the fluid pump <NUM> allows for easy and consistent manufacturing processes that can be used to produce a repeated and consistent manufactured product that can be assembled without the use of external fasteners, such as bolts, screws, and other similar external fasteners. Stated another way, the pump cover <NUM>, the pump body <NUM> and the gerotor assembly <NUM> are self-aligning within the pump housing <NUM> and can only be installed in a very limited number of rotational configurations. Typically, the pump body <NUM> and the pump cover <NUM> can only be installed in a single rotational position with respect to the pump housing <NUM>. This single rotational position is promoted by the alignment feature <NUM> of the pump housing <NUM>. The use of the alignment feature <NUM> also allows for axial movement of at least the pump cover <NUM>, as will be described more fully below.

The gerotor assembly <NUM> includes an internal gear <NUM> that is centered within the pump housing <NUM> and which attaches to the drive shaft <NUM>. During rotation of the rotor <NUM>, the internal gear <NUM> of the gerotor assembly <NUM> rotates within the eccentric outer component <NUM> of the gerotor assembly <NUM> to operate the pump assembly <NUM> of the fluid pump <NUM>.

In order to retain the pump body <NUM>, gerotor assembly <NUM> and pump cover <NUM> within the pump housing <NUM>, the spring assembly <NUM> for the fluid pump <NUM> is installed within the retaining channel <NUM> of the pump housing <NUM>. This retaining channel <NUM> is defined within an inner surface <NUM> of the pump housing <NUM> and near an outer rim <NUM> of the motor end <NUM> of the pump housing <NUM>. An outer edge <NUM> of the pump cover <NUM> is installed within the retaining channel <NUM> along with a biasing member <NUM> and a retaining ring <NUM>. The retaining ring <NUM> helps to secure the pump cover <NUM>, the pump body <NUM> and the biasing member <NUM> within the retaining channel <NUM>. In this manner, the retaining ring <NUM> is secured within a locking recess <NUM> of the retaining channel <NUM>. The biasing member <NUM> is typically in the form of a pre-load spring <NUM>. This pre-load spring <NUM> can be in the form of a ring-shaped member with a plurality or series of resilient undulations that serve to provide a biasing member <NUM> that biases the pump cover <NUM> away from the retaining ring <NUM>, which is maintained within the locking recess <NUM>. The biasing member <NUM> serves to separate the pump cover <NUM> and the retaining ring <NUM>. These features are contained within the retaining channel <NUM> of the pump housing <NUM>. The spring assembly <NUM> also biases the rotor <NUM> toward the bearing assembly <NUM> without using external fasteners.

The use of the pre-load spring <NUM> that is defined between the retaining ring <NUM> and the pump cover <NUM> provides for a minimal amount of sliding movement <NUM> of the pump cover <NUM> in the axial direction <NUM> within the retaining channel <NUM>. Additionally, the configuration of the alignment feature <NUM> provides for rotational alignment of the pump cover <NUM>, while also providing for the sliding movement <NUM> in the axial direction <NUM> that is parallel with the rotational axis <NUM> of the rotor <NUM>. This minimal amount of sliding movement <NUM> allows for a certain amount of thermal expansion of the various components of the fluid pump <NUM> during operation of the fluid pump <NUM>. In certain aspects of the device, the retaining ring <NUM> may also be afforded some limited movement within the locking recess <NUM>.

By way of example, and not limitation, the fluid pump <NUM> can be used to move fluids that may experience a wide range of temperature fluctuations. As the fluid experiences these temperature fluctuations, the temperature fluctuations can change the viscosity of the fluid and, in certain aspects of the device, can also cause the various components of the fluid pump <NUM> to experience similar temperature fluctuations. These temperature fluctuations may result in expansion and/or contraction of various components of the fluid pump <NUM>. This thermal expansion and contraction of the fluid and components of the fluid pump <NUM> can be absorbed by the pre-load spring <NUM> of the fluid pump <NUM>. Because the fluid pump <NUM> does not include any external fasteners within the pump body <NUM>, the pump assembly <NUM> and the pump cover <NUM>, the thermal expansion and contraction of the fluid and the various materials of the fluid pump <NUM> are allowed to take place. These movements are allowed to be absorbed by the pre-load spring <NUM>. Accordingly, internal stresses are minimized by providing for a mechanism that absorbs various viscosity fluctuations of the fluid and internal dimensional fluctuations of the various materials of the fluid pump <NUM>.

Additionally, while manufacturing processes are relatively consistent, manufacturing tolerances may be experienced between various manufactured components. Accordingly, use of the pre-load spring <NUM> that is disposed between the retaining ring <NUM> and the pump cover <NUM> allows for a mechanism that absorbs various tolerances that may be experienced between manufactured components of different fluid pumps <NUM>. Accordingly, these manufacturing tolerances can be accounted for and a certain amount of variation within the manufactured components may be acceptable during manufacture of the various components of the fluid pump <NUM>. By increasing the dimensional tolerances that may be acceptable within the fluid pump <NUM>, manufacturing costs can be decreased and the amount of waste experienced during the manufacturing process can also be decreased.

As exemplified in <FIG>, the fluid pump <NUM> can include a rotor <NUM> that operates with respect to a stator <NUM>. The stator <NUM> can include a number of stator poles <NUM> that receive windings <NUM> that are wrapped around the various poles <NUM>. As the windings <NUM> receive electrical current, these windings <NUM> are energized and provide an electromagnetic communication between the windings <NUM> of the stator <NUM> and the various magnets <NUM> that are positioned within the body <NUM> of the rotor <NUM>. As the windings <NUM> are energized, the electromagnetic communication produces an electromagnetic force that rotates the rotor <NUM> within the stator <NUM>. As discussed above, the stator <NUM>, windings <NUM> and the stator poles <NUM> can be overmolded by the overmold material <NUM> that forms the pump housing <NUM>.

As exemplified in <FIG>, assembly of the fluid pump <NUM> can include various repeatable steps that may be accomplished without the need for external fasteners securing the various components to the pump housing <NUM>. As exemplified in <FIG>, the rotor <NUM> can be disposed within the stator <NUM> that is overmolded within the material that forms the pump housing <NUM>. When the rotor <NUM> is located, the pump body <NUM> can be installed within the pump housing <NUM> (shown in <FIG>) and the pump sleeve <NUM> can be inserted into the rotor channel <NUM> to at least partially surround the drive shaft <NUM> of the rotor <NUM>. After the pump body <NUM> is installed, the gerotor assembly <NUM> can be installed within the pump receptacle <NUM> of the pump body <NUM> (shown in <FIG>).

As discussed previously, the pump receptacle <NUM> of the pump body <NUM> can typically be positioned in an off-center or eccentric position with respect to the rotor <NUM> and the drive shaft <NUM>. The central internal gear <NUM> of the gerotor assembly <NUM> is typically centrally aligned within the pump housing <NUM> to be rotated by the drive shaft <NUM>. After the gerotor assembly <NUM> is installed, the pump cover <NUM> is installed on top of the gerotor assembly <NUM> (shown in <FIG>). As discussed above, the pump housing <NUM> includes various alignment features <NUM> that serve to provide a single rotational orientation of the pump body <NUM> and the pump cover <NUM> within the pump housing <NUM>. As discussed above, these locating features serve to rotationally align the components of the fluid pump <NUM> within the pump housing <NUM> so that additional fasteners are not needed for rotationally locating the pump body <NUM> and the pump cover <NUM>.

After the pump cover <NUM> is installed, the pre-load spring <NUM> and retaining ring <NUM> are positioned within the retaining channel <NUM> of the pump housing <NUM> (shown in <FIG>). Accordingly, an outer edge <NUM> of the pump cover <NUM> is also positioned within the retaining channel <NUM> and the pre-load spring <NUM> biases the pump cover <NUM> toward the pump body <NUM> and away from the retaining ring <NUM> secured within the locking recess <NUM>. Through this configuration, the alignment features <NUM> of the pump housing <NUM> serve to rotationally align the pump body <NUM> and the pump cover <NUM>. Simultaneously, the pre-load spring <NUM> serves to axially position the pump cover <NUM>, the pump body <NUM> and the rotor <NUM> within the pump housing <NUM>, while also providing a tolerance-absorbing space and expansion and contraction-absorbing space within the fluid pump <NUM>.

Through this configuration of the pre-load spring <NUM> and the alignment features <NUM> of the pump housing <NUM>, the components of the fluid pump <NUM> can be rotationally and axially aligned within the pump housing <NUM> while also providing for a limited amount of movement within the fluid pump <NUM> that can absorb thermal expansion and contraction movements and also various manufacturing tolerances of the manufactured components.

According to various aspects of the device, an outer surface <NUM> of the pump housing <NUM> can include sealing grooves <NUM> that can retain one or more O-rings <NUM> that can be used to seal an outer surface <NUM> of the pump housing <NUM> with respect to the fluid-handling assembly <NUM> within which the fluid pump <NUM> is installed.

According to various aspects of the device, the fluid pump <NUM> can include various configurations where the fluid inlet <NUM> and fluid outlet <NUM> can be positioned on various portions of the pump housing <NUM> and/or the pump cover <NUM>. Accordingly, the fluid inlet <NUM> and fluid outlet <NUM> can each be positioned within the pump cover <NUM>. Alternatively, the fluid inlet <NUM> can be installed within a sidewall <NUM> of the pump housing <NUM> and the fluid outlet <NUM> can be installed within the pump cover <NUM>, or vice versa. Accordingly, the fluid pump <NUM> can be manufactured to be installed within a wide range of fluid-handling assemblies and a wide range of configurations of fluid-handling assemblies. These fluid-handling assemblies can include, but are not limited to, transmissions, fluid delivery mechanisms, and other similar fluid-handling assemblies.

Claim 1:
A fluid pump (<NUM>) comprising:
a stator (<NUM>);
a rotor (<NUM>) rotationally operable with respect to the stator (<NUM>);
a drive shaft (<NUM>) that extends from the rotor (<NUM>) to a pump assembly (<NUM>) that delivers a fluid from an inlet (<NUM>) to an outlet (<NUM>);
a pump housing (<NUM>) that includes an interior cavity (<NUM>) that contains the stator (<NUM>), the rotor (<NUM>) and the pump assembly (<NUM>);
a pump cover (<NUM>) that is disposed at an end of the pump housing (<NUM>), wherein the pump cover (<NUM>) defines an end (<NUM>) of the interior cavity (<NUM>); and
a spring assembly (<NUM>) that biases the pump cover (<NUM>) in an axial direction (<NUM>) toward the pump assembly (<NUM>),
characterized in that the pump housing (<NUM>) is overmolded around the stator (<NUM>) to define the interior cavity (<NUM>).