Wet rotor pump motor stator sealing liner

BACKGROUND

0001This application relates to a sealing liner to be incorporated into a motor for a pump, wherein pump fluid cools the motor.

0002Pumps are typically driven by electric motors. In one known type of electric motor, pump fluid is allowed to flow across a motor rotor for cooling the motor rotor. The motor rotor is isolated from the motor stator by a sealing liner.

0003In known motors, a position sensor, which may be known as a resolver, is also incorporated to determine the current position of the motor rotor. This is required to provide feedback to a motor control of the position of the pump which is driven by the motor rotor.

0004In the prior art, separate sealing liners have been utilized for areas associated with a static portion of the resolver, and a rotating portion of the resolver.

0005Typically, the resolver has been of a different diameter than the remainder of the motor stator and a portion of the resolver associated with the rotor has also been of a different diameter than the rotor.

SUMMARY

0006A sealing liner for use in a pump motor incorporates a radially enlarged portion at one end, and a radially smaller portion extending from the one end to an opposed end. A length of the overall sealing liner including the radially smaller portion and the radially enlarged portion is defined as a first length. A length of said radially enlarged portion is defined as a second length. A ratio of the first length to the second length is between approximately 6.5 and approximately 8.5. A stator assembly, a pump and a method are also disclosed.

0007The invention also provides a stator assembly for a motor for driving a pump comprising: a stator; a position sensor operable to sense a position of an associated portion that rotates with a rotor received within said stator; and a sealing liner, said sealing liner being positioned radially inward of said stator and said position sensor, said sealing liner having a radially enlarged portion at one end, and a radially smaller portion extending from said one end to an opposed end, a length of the sealing liner including the radially smaller portion and the radially enlarged portion being defined as a first length, and a length of said radially enlarged portion being defined as a second length, and a ratio of said first length to said second length being between about 6.5 and about 8.5.

0008The invention also provides a pump comprising: a motor driving a pump, said motor including a stator, and a position sensor; a rotor rotating with a sensor portion; and a passage to communicate fluid from the pump into a chamber surrounding said rotor, and a sealing liner separating said chamber from said stator; and said sealing liner also separating said position sensor, and said sensor portion.

0009These and other features of the invention will be better understood from the following specification and drawings, the following of which is a brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

0010<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> shows a motor structure including a sealing liner according to an exemplary embodiment of the invention.</li><li><figref idref="f0002">Figure 2</figref> shows the sealing liner as part of the embodiment.</li></ul>

DETAILED DESCRIPTION

0011<figref idref="f0001">Figure 1</figref> shows a pump assembly 20 having a pump unit 22 which is driven by a motor 24. The motor 24 incorporates a stator 28 driving a rotor 26 in a known manner. As shown schematically at P, pump fluid is allowed to flow across the rotor 26 for cooling. In fact, the actual flow of the pump fluid for cooling purposes may travel along the outside of the rotor 26 from the pump 22 into the motor 24, and then be discharged through the inside of the rotor 26, as generally shown by the arrows P.

0012A position sensor 32, which may be a resolver, sits adjacent the stator 28. A sensor portion 30 of a position sensor 32 rotates with the rotor 26. A chamber 35 receives the rotor 26 and also receives the pump fluid from the connection P. Sensor 32 senses the position of portion 30, and communicates with a control (not shown).

0013A sealing liner 34 is generally cylindrical in shape and incorporates a radially enlarged or thickened end 36, a rotor portion 38, and a sensing portion 40. The rotor portion 38 and the portion 40 have generally the same diameter, and thus, the part may be extruded. The sealing liner 34 thus extends between the rotor 26 and stator 28, and between sensor 32 and sensor rotor portion 30. The sealing liner 34 extends between open axial ends.

0014<figref idref="f0002">Figure 2</figref> shows the sealing liner 34 having the radially enlarged portion 36 extending for a length L₂. The overall sealing liner 34, including the portions 36, 38, and 40 extends for a length L₁.

0015L₂. may be about .63" (about 1.6 cm) and L₁ was about 5.3" (about 13.4 cm) in one embodiment and about 4.1" (about 10.4 cm) in another. In embodiments, a ratio of L₁ to L₂. is between approximately 6.5 and approximately 8.5.

0016The inner periphery of the portions 38 and 40 is defined by a dimension d₁, and the outer periphery is defined by a dimension d₂. In one embodiment, d₁ may be about 1.58" (about 4 cm) and d₂ may be about 1.64" (4.2 cm). A ratio of d₁ to L₁ may be between approximately .4 and approximately .33.

0017The sealing liner 34 may be formed of carbon fiber filled polyetheretherketone (PEEK). However, other suitable materials may be used. Specific examples would include Victrex 450CA30™, or 30% carbon fiber filled PEEK.

0018Although embodiments of this invention have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.