Patent Application
20150233480
1. Field of the Invention
The present disclosure relates to electrical generators, and more particularly to lubricant pressure regulating valves for use in electrical generators.
2. Description of Related Art
Many aircraft systems and auxiliary systems include generators. Generators typically include a rotor and a stator each having electric windings. A source of rotation, such as a gas turbine engine, rotates the rotor such that the rotor windings move relative to the stator windings. The relative rotation of the rotor windings adjacent to the stator windings generates electricity.
Generators typically require lubrication for efficient operation. Lubrication systems providing such lubricant to generators generally include a pump for supplying pressurized lubricant to the generator. They also include pressure-regulating valves for maintaining lubricant pressure within a predetermined pressure range. Such pressure regulating valves commonly include a valve sleeve with a valve spool disposed within the valve sleeve. The valve spool moves within the valve sleeve in response to lubricant pressure. The movement of the valve spool regulates lubricant flow between inlet and outlet ports defined in the valve sleeve and fluidly coupled to the generator.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved pressure regulating valves. The present disclosure provides a solution for this need.
A pressure regulating valve includes a valve body and a screen body. The screen body wraps around the valve body and is joined to itself at a screen joint for coupling the screen body to the valve body, e.g., without welding the screen body to the valve body. A screen section defined on the screen body is configured to strain lubricant entering the valve body.
In certain embodiments, the screen body can include an anti-rotation structure fixing the screen body in rotation about the valve body. The anti-rotation structure can register the screen section with respect to an inlet defined in the valve body for screening lubricant entering the valve body through the inlet. The anti-rotation structure can be defined on the screen joint. The anti-rotation structure can include a tab extending from the screen body. A corresponding notch defined in the valve body can seat the tab of the screen body in the valve body. The notch and the tab can extend axially along the length of the valve body screen body, respectively.
In accordance with certain embodiments, the valve body can have an annular collar bounding a first circumferential edge of the screen body. The annular collar can be a first annular collar and the screen body can have a second annular collar bounding a second circumferential edge of the screen body. It is contemplated that either or both the annular collars can form a seat for an o-ring for sealing the valve body with a housing of an electrical generator.
It is also contemplated that in certain embodiments the anti-rotation structure can include a stake and a stake-receiving aperture for fixing the screen body axially and in rotation with respect to the valve body. The stake can be formed on the valve body and the stake-receiving aperture can be defined in the screen body. The stake can extend radially outward from the valve body for seating within the stake-receiving aperture in the screen body.
It is further contemplated that in certain embodiments the screen joint can include a weld coupling axial edges of the screen body together. The screen section can include wire mesh, a perforated sheet, or any other suitable straining element for separating debris above a predetermined size from lubricant transiting the screen section. The valve body can have an outlet and can include a movable member with a first position and a second position. Lubricant flow between the inlet and the outlet can be greater in the first position than the second position. The outlet can be a scheduled outlet configured for cooperatively regulating lubricant inlet pressure with the movable member.
These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.
So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of the pressure regulating valve in accordance with the disclosure is shown in
Pressure regulating valve 100 includes a valve body 110 and a screen body 150. Valve body 110 has at least one lubricant inlet 112 (shown in
Movable member 116 is movable between a first axial position and a second axial position within the interior of valve body 110. Movement of movable member 116 cooperates with the shape of outlet 114 for varying lubricant flow through valve body 110 in response to lubricant pressure at lubricant inlet 112. Lubricant flow through valve 100 is greater when movable member 116 is in its first axial position than when movable member 116 is in its second position. Other aspects of the movable member 116, e.g. valve spools and valve sleeves, are described in U.S. Pat. No. 8,485, 218, the contents of which are incorporated herein by reference in their entirety.
Screen body 150 includes a screen section 152 and a screen joint 154. Screen section 152 is configured for straining lubricant entering valve body 110 through lubricant inlet 112. This prevents debris that may be entrained in the lubricant from entering into valve body 110 and interfering with operation of movable member 116. In embodiments, screen section 152 includes wire mesh 160 (shown in
Axial edges of screen body 150 connect to one another to form an axially extending screen joint 154 extending axially along pressure regulating valve 100, thereby joining screen body 150 to itself. Screen joint 154 includes a weld 158 joining respective axial edges of the screen body to one another. It is also contemplated that the screen joint 154 can also be crimped or brazed. This makes screen body 150 integral with and inseparable from valve body 110, indirectly coupling screen body 150 to valve body 110 without directly welding or fastening screen body 150 to valve body 110.
With reference to
Valve body 110 has a first annular collar 122 and a second annular collar 124. First annular collar 122 bounds a first circumferential edge 126 of screen body. Second annular collar 124 bounds a second circumferential edge 128 of the screen body. First annular collar 122 limiting displacement of screen body 150 in a first direction along axis A (shown in
With reference to
Conventional pressure regulating valves do not include a screen body over their inlet. Since some lubrication systems can include entrained debris, debris can become lodged within the valve body and potentially restrict the movement of movable elements within the valve. Embodiments of valves described herein include an integral (inseparable) screen body, preventing debris entry into the valve. Embodiments of valves described herein also have screen bodies attached by welding to the screen body without developing a heat-affected zone on the valve body. This can prevent microcracking or other damage to valve body 110 from exposure to heat during welding that can potentially reduce the valve operation efficiency. Embodiments of valves described herein can also fix the screen body in rotation with respect to the valve body. This can prevent the generation of wear debris by preventing lubricant flowing through the screen from causing the screen to rotate about the valve body, thereby generating debris and eroding the valve body or screen.
The methods and systems of the present disclosure, as described above and shown in the drawings, provide for pressure regulating valves with superior properties including integral screen bodies that fixedly attach to the valve body indirectly and without welding or fasteners. While the apparatus and methods of the subject disclosure have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and scope of the subject disclosure.
