Patent Description:
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. Some known valves are shown in <CIT>, <CIT> and <CIT>.

The present invention is defined by the subject-matter of the independent claim.

A low torque rotary valve for a vehicle cooling system is provided.

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.

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 <NUM>, even if such combinations are not explicitly claimed in the appended claims.

Referring to <FIG>, a multi-port rotary valve in accordance with a first embodiment is illustrated and generally designated <NUM>. The rotary valve <NUM> includes a valve housing <NUM> containing a tapered valve body <NUM>, a rotatable disk <NUM>, and a rotatable clutch <NUM>. As discussed below, the tapered valve body <NUM> is lifted by action of a spring <NUM> during rotation of the rotatable disk <NUM> in a first direction and thereafter seated after the rotatable disk <NUM> is counter-rotated. The rotatable clutch <NUM> prevents the valve body <NUM> from rotating in the opposite direction. Because the tapered valve body <NUM> is lifted during rotation, the sealing members <NUM>, <NUM> are uncompressed, and a lower torque demand is required, thereby allowing for a smaller and less costly motor actuator. Each such feature of the rotary valve <NUM> is discussed below.

The valve housing <NUM> generally includes an upper housing <NUM> and a lower housing <NUM> that collectively define an enclosure for the tapered valve body <NUM>, the rotatable disk <NUM>, the rotatable clutch <NUM>, and the spring <NUM>. The lower housing <NUM> includes a tapered sidewall <NUM> extending upwardly and outwardly from a lower end-wall <NUM>. The tapered sidewall <NUM> includes at least one inlet port <NUM> and at least one outlet port <NUM>. The inlet port <NUM> and the outlet port <NUM> each define a flow passage that is generally orthogonal to the rotational axis <NUM> of the tapered valve body <NUM>. While two ports are shown in the <FIG>, in other embodiments a greater number of inlet ports and/or outlet ports can be used in other embodiments. In still other embodiments, the ports are bi-directional, such that any given port can function as both an inlet port and an outlet port, dependent on the orientation of the tapered valve body <NUM> within the valve housing <NUM>.

The upper housing <NUM> includes a cylindrical sidewall <NUM> extending downward from an upper end-wall <NUM>. The upper and lower housing <NUM>, <NUM> include respective flanges <NUM>, <NUM> that are joined to each other according to any suitable method to provide a liquid-tight seal about the periphery of the valve housing <NUM>. For example, the upper flange <NUM> can be ultrasonically welded to the lower flange <NUM>, while in other embodiments the upper flange <NUM> is secured to the lower flange <NUM> via a plurality of fasteners that extend into aligned openings in the respective flanges <NUM>, <NUM>. Because the housing <NUM> is tapered, the upper end-wall <NUM> includes an outer diameter that is greater than the outer diameter of the lower end-wall <NUM>. In addition, the upper end-wall <NUM> includes a central aperture <NUM> for a stem <NUM> extending upwardly from the rotatable disk <NUM>.

The rotatable disk <NUM> includes a head <NUM> fixedly joined to the aforementioned stem <NUM>. The stem <NUM> is adapted to transfer torque from a motor actuator to the head <NUM> of the rotatable disk <NUM>. The rotatable disk <NUM> includes an axis of rotation that is concentric with the rotational axis <NUM> of the tapered valve body <NUM>. The head <NUM> is disk-shaped and includes a lower surface <NUM> having at least one ramped projection <NUM>. The ramped projection <NUM> makes sliding contact with a corresponding ramped projection <NUM> on the tapered valve body <NUM> while rotating to impart axial motion to the tapered valve body <NUM>. 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 <NUM> degrees in the illustrated embodiment but can be greater than or less than <NUM> degrees in other embodiments. For n-number of ramped projections, each projection spans approximately <NUM>/n degrees in the circumferential direction. For example, if the rotatable disk <NUM> includes two ramped projections, each ramped projection spans approximately <NUM> degrees in the circumferential direction. If the rotatable disk <NUM> includes three ramped projections, each ramped projection spans approximately <NUM> degrees in the circumferential direction. If the rotatable disk <NUM> includes four ramped projections, each ramped projection spans approximately <NUM> 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 <NUM>, such that at least two of the ramped projection sweep through a different angular range, e.g., one projection spanning <NUM> degrees and the other projection spanning <NUM> degrees.

As also shown in <FIG>, the tapered valve body <NUM> includes a sloped outer surface <NUM>. The sloped outer surface <NUM> is V-shaped and increases in diameter in the vertical direction when viewed from the side (i.e., the diameter of the sloped outer surface <NUM> increases along the height of the tapered valve body <NUM>). The tapered valve body <NUM> includes at least one flow-passage <NUM> therethrough, the flow passage <NUM> being transverse to the rotational axis <NUM> of the tapered valve body <NUM>. While a single flow-passage <NUM> is shown in <FIG>, in other embodiments the tapered valve body <NUM> includes two, three, or more flow passages.

As noted above, the tapered valve body <NUM> includes an upper surface having at least one ramped projection <NUM>. The ramped projection(s) <NUM> of the tapered valve body <NUM> make sliding contact with ramped projection(s) <NUM> of the rotatable disk <NUM>. Each ramped projection <NUM> of the tapered valve body <NUM> includes a uniform pitch, such that the ramped projection gradually increases from a minimum height to a maximum height. The pitch is approximately <NUM> degrees in the illustrated embodiment but can be greater than or less than <NUM> degrees in other embodiments. As with the rotatable disk <NUM>, the tapered valve body <NUM> can include n-number of ramped projections that span <NUM>/n degrees in the circumferential direction. Further optionally, the ramped projections of the tapered valve body <NUM> can be asymmetrically disposed, such that at least two of the ramped projection sweep through a different angular range, e.g., one projection spanning <NUM> degrees and the other projection spanning <NUM> degrees.

As also shown in <FIG>, the rotary valve <NUM> includes a rotatable clutch <NUM> and a spring element <NUM>. The spring element <NUM> is adapted to bias the valve body <NUM> upwardly against the rotatable disk <NUM>. The rotatable disk <NUM> is constrained in the vertical direction but has rotational freedom when driven by a rotary actuator. The spring element <NUM> is a helical compression spring in the illustrated embodiment but can include other spring elements in other embodiments. The rotatable clutch <NUM> is coupled to the lower extent of the tapered valve body <NUM> and is adapted to permit rotation of the tapered valve body <NUM> in only a single direction (e.g., clockwise or counter-clockwise). The present invention is not limited to a particular rotatable clutch (also referred to as an overrunning clutch). Examples include a ratchet clutch, a sprag clutch, a compliant clutch, and a roller clutch. Still other rotatable clutches can be used in other embodiments.

In operation, the tapered valve body <NUM> is lifted and rotated during rotation of the rotatable disk <NUM> in a first direction and thereafter seated after the rotatable disk <NUM> is counter-rotated. As shown in <FIG> for example, the sealing members <NUM>, <NUM> are initially compressed between the tapered valve body <NUM> and the tapered sidewall <NUM>. Rotation of the rotatable disk <NUM> in the counter-clockwise direction causes the tapered valve body <NUM> to travel vertically by action of the compression spring <NUM>. <FIG> depicts the seals <NUM>, <NUM> in the uncompressed state. The valve body <NUM> rotates in unison with the rotatable disk <NUM> in the counter-clockwise direction, as the rotatable disk <NUM> remains frictionally engaged with the tapered valve body <NUM>. After the tapered valve body <NUM> is rotated by the desired amount, the rotatable disk <NUM> reverses direction. The ramped projection <NUM> of the rotatable disk <NUM> drives the valve body <NUM> downward, against the spring <NUM>, thereby compressing the seals <NUM>, <NUM> surrounding each port <NUM>, <NUM>, while the rotatable clutch <NUM> prevents the rotation of the tapered valve body <NUM> in the reverse direction.

Referring now to <FIG>, an example of a multi-port rotary valve is illustrated and generally designated <NUM>. The rotary valve <NUM> of <FIG> is structurally and functionally similar to the rotary valve <NUM> of <FIG>, except that ramped projections of the rotatable disk are integrally formed with the upper housing. The rotatable clutch is also omitted, as this embodiment allows for bi-directional rotation of the valve body.

More specifically, the rotary valve <NUM> of <FIG> includes a valve housing <NUM>, a tapered valve body <NUM>, an input shaft <NUM>, and a spring element <NUM>. The valve housing <NUM> includes an upper housing <NUM> and a lower housing <NUM> that cooperate to define an enclosure for the tapered valve body <NUM>. The upper housing <NUM> includes a tapered sidewall <NUM> extending downwardly and outwardly from an upper end-wall <NUM>. The tapered sidewall <NUM> includes four ports <NUM> that each define a flow passage that is generally orthogonal to the rotational axis <NUM> of the tapered valve body <NUM>. While four ports <NUM> are shown in the <FIG>, in other embodiments the valve housing <NUM> can include a different number of ports. The lower housing <NUM> includes a cover having a spring seat <NUM> for the spring element <NUM>. The upper end-wall <NUM> includes a central aperture <NUM> for the input shaft <NUM>, shown in <FIG>. The upper and lower housings <NUM>, <NUM> are joined to each other according to any suitable method. Because the upper housing <NUM> is tapered, the upper end-wall <NUM> includes an outer diameter that is less than the outer diameter of the lower housing <NUM>.

An inverted view of interior of the upper housing <NUM> is shown in <FIG>. The upper housing <NUM> includes a repeating series of ramped projections <NUM>-optionally configured as an undulating camming surface-that extend around the circumference of the upper-end wall <NUM>. The tapered valve body <NUM> and the input shaft <NUM> are also shown in <FIG>. The tapered valve body <NUM> includes a sloped outer surface <NUM>. The valve body <NUM> is frustoconical and narrows in the vertical direction (i.e., the diameter of the sloped outer surface <NUM> decreases along the height of the valve body <NUM>). The tapered valve body <NUM> includes at least one flow-passage <NUM> therethrough, the at least one flow passage <NUM> being transverse to the rotational axis <NUM> of the tapered valve body <NUM>. While the tapered valve body <NUM> includes a "X" shaped channel for connecting four ports <NUM>, the tapered valve body <NUM> can alternatively include a single "L" shaped channel for connecting two ports, a single "T" shaped channel for connecting three ports, or two "L" shaped channels for connecting four ports, each being transverse to (and optionally intersecting) the rotational axis <NUM> of the tapered valve body <NUM>. Other configurations are possible.

The upper surface <NUM> of the valve body <NUM> also includes a plurality of discontinuous projections <NUM> that are spaced apart from each other. The projections <NUM> extend vertically from the upper surface <NUM> of the valve body <NUM> and engage the ramped projections <NUM> in the housing <NUM>. For n-number of projections, each projection is spaced apart from the adjacent projections by approximately <NUM>/n degrees. For example, if the valve body <NUM> includes four projections as shown in <FIG>, each projection is spaced apart from the adjacent projection by approximately <NUM> degrees. In still other embodiments, the projections are asymmetrically disposed about the upper surface <NUM> of the valve body <NUM>, such that the spacing between adjacent projections varies. While four projections are shown in <FIG>, greater or fewer number of projections can be included in other embodiments. In an alternative embodiment, the housing <NUM> can include the discontinuous projections <NUM> while the valve body <NUM> includes the ramped projections <NUM>. In still an alternative embodiment, each of the housing <NUM> and the valve body <NUM> includes ramped projections substantially as discussed in connection with <FIG> above.

As noted above, the rotary valve <NUM> also includes an input shaft <NUM>. The input shaft <NUM> extends through the central opening <NUM> in the upper valve housing <NUM>. The input shaft <NUM> is rotatable in the clockwise and counter-clockwise directions, and the valve body <NUM> rotates in unison with the input shaft <NUM>. The valve body <NUM> includes a socket opening <NUM> (visible in <FIG>) that receives the head <NUM> of the input shaft <NUM>. The socket opening <NUM> and the head <NUM> include a matching geometry such that that rotation of the input shaft <NUM> causes a corresponding rotation of the valve body <NUM>. The tapered valve body <NUM> is free to oscillate axially relative to the input shaft <NUM> while remaining engaged with the input shaft <NUM>.

Rotation of the tapered valve body <NUM> relative to the valve housing <NUM> causes the projections <NUM> on the upper surface <NUM> of the tapered valve body <NUM> to engage the undulating camming surface <NUM> on the underside of the upper-end wall <NUM>. The camming surface <NUM> causes the tapered valve body <NUM> to displace axially, thereby decompressing the sealing members <NUM> (e.g., o-rings) surrounding the channel openings <NUM> in the tapered valve body <NUM>.

In a first position as shown in <FIG>, the tapered valve body <NUM> is lifted by action of the spring element <NUM>, and the sealing members <NUM> are compressed between the tapered valve body <NUM> and the valve housing <NUM>. A compressible shaft seal <NUM> extends around the stem <NUM> of the input shaft <NUM> to prevent the escape of fluid from the rotary valve <NUM>. Rotation of the input shaft <NUM> in the clockwise or counter-clockwise direction causes the tapered valve body <NUM> to travel axially downward against the spring element <NUM>. <FIG> depicts the sealing members <NUM> in the uncompressed state, caused by the downward travel of the valve body <NUM>. After the valve body <NUM> is rotated by the desired amount, such that the channel openings <NUM> are aligned with the input/output ports <NUM>, the input shaft <NUM> stops rotating. The spring element <NUM> drives the valve body <NUM> upward, thereby compressing the sealing members <NUM> around the channel openings <NUM>.

Referring now to <FIG>, an example of a multi-port rotary valve is illustrated and generally designated <NUM>. The rotary valve <NUM> of <FIG> is structurally and functionally similar to the rotary valve <NUM> of <FIG>, except that the undulating camming surface is integrally formed with the valve body, rather than the valve housing. The spring element biases the tapered valve body downwardly, and the rotatable clutch is omitted (similar to <FIG>) to also allow for bi-directional rotation of the valve body.

More specifically, the rotary valve <NUM> of <FIG> includes a valve housing <NUM>, a tapered valve body <NUM>, an input shaft <NUM>, and a spring element <NUM>. The valve housing <NUM> includes an upper housing <NUM> and a lower housing <NUM> that cooperate to define an enclosure for the tapered valve body <NUM>. The upper housing <NUM> includes a tapered sidewall <NUM> extending downwardly and inwardly from an upper end-wall <NUM>. The tapered sidewall <NUM> includes four ports <NUM> that each define a flow passage that is generally orthogonal to the rotational axis <NUM> of the tapered valve body <NUM>. While four ports <NUM> are shown in the <FIG>, in other embodiments the valve housing <NUM> can include a different number of ports.

The upper housing <NUM> also includes an upwardly extending cylindrical sleeve <NUM>. The cylindrical sleeve <NUM> includes an annular lip <NUM> that provides a seat for the spring element <NUM>, which extends around a stem <NUM> protruding upwardly from the valve body <NUM>. The lower housing <NUM> includes a plurality of discontinuous projections <NUM> that are spaced apart from each other about the circumferences of the lower housing <NUM>. For n-number of projections, each projection is spaced apart from the adjacent projections by approximately <NUM>/n degrees. For example, if the lower housing <NUM> includes four projections as shown in <FIG>, each projection is spaced apart from the adjacent projection by approximately <NUM> degrees. In still other embodiments, the projections are asymmetrically disposed about the lower housing <NUM>, such that the spacing between adjacent projections varies.

The tapered valve body <NUM> is frustoconical and widens in the vertical direction (i.e., the outer diameter of the tapered valve body <NUM> increases along its height). As noted above, the tapered valve body <NUM> includes a camming surface <NUM> comprising a repeating series of undulations that extend around the circumference of the downward facing surface <NUM> of the tapered valve body <NUM>. The tapered valve body <NUM> also includes at least one flow-passage <NUM> therethrough, the at least one flow passage <NUM> being transverse to the rotational axis <NUM> of the tapered valve body <NUM>. While the tapered valve body <NUM> includes a "X" shaped channel in the illustrated embodiment, the tapered valve body <NUM> can alternatively include a single "L" shaped channel, a single "T" shaped channel, or two "L" shaped channels. Other configurations are possible.

In a first position as shown in <FIG>, the valve body <NUM> is biased downward by action of the spring element <NUM>, and the sealing members <NUM> are initially compressed between the tapered valve body <NUM> and the housing valve housing <NUM>. Rotation of the input shaft <NUM> in the clockwise or counter-clockwise direction causes the tapered valve body <NUM> to travel axially upward against the spring element <NUM> by action of the camming surface <NUM> against the projections <NUM>. <FIG> depicts the sealing members <NUM> in the uncompressed state. After the tapered valve body <NUM> is rotated by the desired amount, such that the channel openings <NUM> are aligned with the input/output ports <NUM>, the input shaft <NUM> stops rotating. The spring element <NUM> drives the valve body <NUM> downward, thereby compressing the sealing members <NUM>.

Claim 1:
A multi-port rotary valve (<NUM>) comprising:
a tapered valve body (<NUM>) defining at least one flow passage between first and second openings, the flow passage extending transverse to a rotational axis (<NUM>) of the tapered valve body (<NUM>);
a rotatable clutch (<NUM>) coupled to a lower extent of the tapered valve body (<NUM>), the rotatable clutch (<NUM>) permitting rotation of the tapered valve body (<NUM>) in only a first direction;
a valve housing (<NUM>) including at least one inlet port and at least one outlet port, the tapered valve body (<NUM>) being biased upwardly within the valve housing (<NUM>) by a spring element (<NUM>);
a rotatable disk (<NUM>) that is adjacent to the tapered valve body (<NUM>) within the valve housing (<NUM>) and having an axis of rotation that is concentric with the rotational axis (<NUM>) of the tapered valve body (<NUM>);
first and second sealing members (<NUM>, <NUM>) adjacent the first and second openings in the tapered valve body (<NUM>) for sealing the tapered valve body (<NUM>) against the valve housing (<NUM>);
wherein an axial surface of the rotatable disk (<NUM>) includes a first projection (<NUM>) and wherein an axial surface of the tapered valve body (<NUM>) includes a second projection (<NUM>), the axial surface of the rotatable disk (<NUM>) being opposite of the axial surface of the tapered valve body (<NUM>);
wherein rotation of the rotatable disk (<NUM>) in the first direction imparts a rotation of the tapered valve body (<NUM>) in the first direction, and rotation of the rotatable disk (<NUM>) in a second direction, opposite of the first direction, drives the tapered valve body (<NUM>) against the spring element (<NUM>) and compresses the first and second sealing members (<NUM>, <NUM>) between the tapered valve body (<NUM>) and the valve housing