Patent Application
20240183453
The present invention relates to rotary valves, and in particular, multi-port rotary valves for controlling coolant flow in battery electric vehicles and for other applications.
Battery electric vehicles rely on complex cooling circuits to ensure the vehicle batteries, power electronics, and the electric motor are operating within an optimal temperature range. These cooling circuits typically include several multi-port rotary valves to help meet the cooling demands of these and other vehicle systems. For example, existing battery electric vehicles include one or more five-port or eight-port rotary valves that direct the flow of coolant to a corresponding number of different routing paths of the vehicle cooling system.
Multi-port rotary valves generally include a valve body that is rotated within a flow passage about an axis that is normal to a flow stream. The valve body can include a number of possible geometries, including tapered and cylindrical plugs, with each such plug defining one or more flow passages therethrough. The valve body can be rotated in the clockwise and/or counter-clockwise directions in response to a motor actuator to thereby open or close the rotary valve.
The sealing ability (leakage rate) of a rotary valve having a tapered valve body is proportional to the torque demand on the motor actuator. To achieve a high sealing ability, high power motor actuators are ordinarily required. In vehicle cooling systems, however, it can be desirable to have a smaller motor actuator, which would decrease the cost associated with the coolant system while also minimizing size and potentially extending service life. Accordingly, there remains a continued need for a multi-port rotary valve that is compatible with low torque motor actuators while maintaining a strong seal of the tapered valve body.
A low torque rotary valve for a vehicle cooling system is provided. The rotary valve includes a tapered valve body that can be lifted during rotation and thereafter seated after being rotated the desired amount. An axial surface of the tapered valve body is in sliding contact with an axial surface of a valve housing or a rotatable disk. As the tapered valve body rotates, one or more ramped projections cause the tapered valve body to displace axially within the valve housing. Sealing members are uncompressed during rotation of the tapered valve body, and a lower torque demand is required, thereby allowing for a smaller and less costly motor actuator.
In one embodiment, the rotary valve includes a rotatable disk having a ramped projection for engaging the tapered valve body. An overrunning clutch is joined to or integral with a lower portion of the tapered valve body to permit rotation of the tapered valve body in only a single direction. When rotating in the first direction, the rotatable disk pushes tangentially on the upper surface of the rotary valve and rotates the valve body in the first direction. Once the tapered valve body is rotated in the first direction by the desired amount, the rotatable disk rotates in the opposite direction. The tapered valve body is prevented from rotating in this opposite direction by the overrunning clutch and is instead driven axially within a valve housing by operation of the ramped projection to compress the sealing members against the interior of the valve housing.
In another embodiment, the rotatable disk and the overrunning clutch are omitted, and the rotary valve instead includes inter-engaging camming surfaces on an axial surface of the tapered valve body and an axial surface of the valve housing. The tapered valve body of this embodiment is bi-directional and is driven by an input shaft extending through the valve housing. Rotation of the tapered valve body within the valve housing causes the camming surfaces to slide over each other and axially displace the tapered valve body against a spring element, such that sealing members between the tapered valve body and the valve housing are at least partially uncompressed during rotation of the tapered valve body within the valve housing.
In these and other embodiments, the tapered valve body includes at least one flow passage extending transverse to a rotational axis of the tapered valve body. The tapered valve body can include a single flow passage in some embodiments, while in other embodiments the tapered valve body includes two or more flow passages. The flow passage or passages can be straight, “L” shaped, “T” shaped, or “X” shaped for connecting two, three, or four ports in the valve housing. The sealing members can include a sealing element, for example an o-ring, surrounding the entrance/exit of each flow passage. In addition, the spring element can include a helical compression spring positioned between an axial surface of the tapered valve body and a portion of the valve housing.
The rotary valve of these and other embodiments decouples the proportional relationship between the sealing ability of the rotary valve and the associated torque demand. The rotary valve provides low resistance to rotation from state to state, simplifies actuator demand, and maintains a strong seal to prevent coolant leakage. The rotary valve can achieve a longer service life when compared to existing, high-torque rotary valves, and the rotary valve can be readily adapted for a wide variety of multi-port configurations for cooling circuits and other systems.
These and other features and advantages of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanying drawings and the appended claims. It will be appreciated that any of the preferred and/or optional features of the invention may be incorporated alone, or in appropriate combination, within embodiments of the invention, while still falling within the scope of claim 1, even if such combinations are not explicitly claimed in the appended claims.
Referring to
The valve housing 12 generally includes an upper housing 26 and a lower housing 28 that collectively define an enclosure for the tapered valve body 14, the rotatable disk 16, the rotatable clutch 18, and the spring 20. The lower housing 28 includes a tapered sidewall 30 extending upwardly and outwardly from a lower end-wall 32. The tapered sidewall 30 includes at least one inlet port 34 and at least one outlet port 36. The inlet port 34 and the outlet port 36 each define a flow passage that is generally orthogonal to the rotational axis 38 of the tapered valve body 14. While two ports are shown in the
The upper housing 26 includes a cylindrical sidewall 40 extending downward from an upper end-wall 42. The upper and lower housing 26, 28 include respective flanges 44, 46 that are joined to each other according to any suitable method to provide a liquid-tight seal about the periphery of the valve housing 12. For example, the upper flange 44 can be ultrasonically welded to the lower flange 46, while in other embodiments the upper flange 44 is secured to the lower flange 46 via a plurality of fasteners that extend into aligned openings in the respective flanges 44, 46. Because the housing 12 is tapered, the upper end-wall 42 includes an outer diameter that is greater than the outer diameter of the lower end-wall 32. In addition, the upper end-wall 42 includes a central aperture 48 for a stem 50 extending upwardly from the rotatable disk 16.
The rotatable disk 16 includes a head 52 fixedly joined to the aforementioned stem 50. The stem 50 is adapted to transfer torque from a motor actuator to the head 52 of the rotatable disk 16. The rotatable disk 16 includes an axis of rotation that is concentric with the rotational axis 38 of the tapered valve body 14. The head 52 is disk-shaped and includes a lower surface 54 having at least one ramped projection 56. The ramped projection 56 makes sliding contact with a corresponding ramped projection 60 on the tapered valve body 14 while rotating to impart axial motion to the tapered valve body 14. Each ramped projection includes a uniform pitch, such that the ramped projection gradually increases from a minimum height to a maximum height. The pitch is approximately 15 degrees in the illustrated embodiment but can be greater than or less than 15 degrees in other embodiments. For n-number of ramped projections, each projection spans approximately 360/n degrees in the circumferential direction. For example, if the rotatable disk 16 includes two ramped projections, each ramped projection spans approximately 180 degrees in the circumferential direction. If the rotatable disk 16 includes three ramped projections, each ramped projection spans approximately 120 degrees in the circumferential direction. If the rotatable disk 16 includes four ramped projections, each ramped projection spans approximately 90 degrees. Still greater number of ramped projections can be used in other embodiments. In other embodiments the ramped projections are asymmetrically disposed about the exterior of the rotatable disk 16, such that at least two of the ramped projection sweep through a different angular range, e.g., one projection spanning 270 degrees and the other projection spanning 90 degrees.
As also shown in
As noted above, the tapered valve body 14 includes an upper surface having at least one ramped projection 60. The ramped projection(s) 60 of the tapered valve body 14 make sliding contact with ramped projection(s) 56 of the rotatable disk 16. Each ramped projection 60 of the tapered valve body 14 includes a uniform pitch, such that the ramped projection gradually increases from a minimum height to a maximum height. The pitch is approximately 15 degrees in the illustrated embodiment but can be greater than or less than 15 degrees in other embodiments. As with the rotatable disk 16, the tapered valve body 14 can include n-number of ramped projections that span 360/n degrees in the circumferential direction. Further optionally, the ramped projections of the tapered valve body 14 can be asymmetrically disposed, such that at least two of the ramped projection sweep through a different angular range, e.g., one projection spanning 270 degrees and the other projection spanning 90 degrees.
As also shown in
In operation, the tapered valve body 14 is lifted and rotated during rotation of the rotatable disk 16 in a first direction and thereafter seated after the rotatable disk 16 is counter-rotated. As shown in
Referring now to
More specifically, the rotary valve 70 of
An inverted view of interior of the upper housing 80 is shown in
The upper surface 102 of the valve body 74 also includes a plurality of discontinuous projections 104 that are spaced apart from each other. The projections 104 extend vertically from the upper surface 102 of the valve body 74 and engage the ramped projections 96 in the housing 72. For n-number of projections, each projection is spaced apart from the adjacent projections by approximately 360/n degrees. For example, if the valve body 74 includes four projections as shown in
As noted above, the rotary valve 70 also includes an input shaft 76. The input shaft 76 extends through the central opening 94 in the upper valve housing 80. The input shaft 76 is rotatable in the clockwise and counter-clockwise directions, and the valve body 74 rotates in unison with the input shaft 76. The valve body 74 includes a socket opening 106 (visible in
Rotation of the tapered valve body 74 relative to the valve housing 80 causes the projections 104 on the upper surface 102 of the tapered valve body 74 to engage the undulating camming surface 96 on the underside of the upper-end wall 86. The camming surface 96 causes the tapered valve body 74 to displace axially, thereby decompressing the sealing members 110 (e.g., o-rings) surrounding the channel openings 100 in the tapered valve body 74.
In a first position as shown in
Referring now to
More specifically, the rotary valve 120 of
The upper housing 130 also includes an upwardly extending cylindrical sleeve 142. The cylindrical sleeve 142 includes an annular lip 144 that provides a seat for the spring element 128, which extends around a stem 148 protruding upwardly from the valve body 124. The lower housing 132 includes a plurality of discontinuous projections 146 that are spaced apart from each other about the circumferences of the lower housing 132. For n-number of projections, each projection is spaced apart from the adjacent projections by approximately 360/n degrees. For example, if the lower housing 132 includes four projections as shown in
The tapered valve body 124 is frustoconical and widens in the vertical direction (i.e., the outer diameter of the tapered valve body 124 increases along its height). As noted above, the tapered valve body 124 includes a camming surface 150 comprising a repeating series of undulations that extend around the circumference of the downward facing surface 152 of the tapered valve body 124. The tapered valve body 124 also includes at least one flow-passage 154 therethrough, the at least one flow passage 154 being transverse to the rotational axis 140 of the tapered valve body 124. While the tapered valve body 124 includes a “X” shaped channel in the illustrated embodiment, the tapered valve body 124 can alternatively include a single “L” shaped channel, a single “T” shaped channel, or two “L” shaped channels. Other configurations are possible in other embodiments.
In a first position as shown in
The above description is that of current embodiment of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. Any reference to elements in the singular, for example, using the articles “a,” “an,” “the,” or “said,” is not to be construed as limiting the element to the singular.
