Cross-Reference to Related Applications

This application claims the benefit of the filing date and disclosure of U.S. Provisional Application Serial No. 61/307,485, filed on February 24, 2010 and is a continuation-in-part application of U.S. Application Serial No. 12/785,844 filed on May 24, 2010, the disclosures of which are explicitly incorporated herein by reference as are all references cited therein. Field of the Invention

This invention relates generally to actuators and, more specifically, to a system for cooling an actuator.

Background of the Invention

This invention relates to actuators which are used in a wide variety of applications to move, actuate, or rotate a part such as, for example, a valve or a switch.

Current actuator designs such as, for example, the actuator design shown in FIGURE 1 of this application incorporate a system for removing the heat generated by the motor and circuit board components of the actuator as well as the heat generated by components surrounding the actuator such as, for example, the heat generated by the gas flowing through an EGR valve coupled to the actuator.

As shown in FIGURE 1 , the actuator 10 depicted therein and of the type disclosed in U.S. Published Patent Application No. US 2010/0301691 is comprised of two main components, i.e., a housing member 12 and a cover member 14 coupled to each other and together defining an interior cavity (shown in U.S. Published Patent Application No. US 2010/0301691 ) in which all of the actuator elements are located such as, for example, the motor, the gears, and the electronics. The housing member 12 incorporates an internal cooling system 16 defined by an elongate, internal cooling chamber or line or conduit 18 unitary and internal with the housing member 12 and terminating in a pair of ports 20 and 22 defined in a top surface or wall 24 of the housing member 12. Although not shown in great detail in FIGURE 1 , it is understood that the internal cooling conduit 18 includes a pair of spaced-apart, parallel, and generally vertical conduit segments 18a (only one of which is shown in FIGURE 1 ) with respective upper ends terminating in the respective ports 20 and 22 and a generally horizontal conduit segment (not shown) extending between and joining the lower ends (not shown) of the vertical conduit segments 18a to define a generally U-shaped internal cooling conduit 18.

An external coolant input line or conduit 23 is coupled to the port 22 and an external coolant outlet line or conduit 23 is coupled to the port 20. A coolant such as, for example, water or antifreeze flows into the actuator 10 from the external coolant input line 23, through the port 22, down through the internal line or conduit 18, up through the outlet port 20, and out through the external coolant outlet line or conduit 21.

However, in applications such as, for example, the application where the actuator 10 is coupled to the shaft of an EGR valve, heat radiates either from the EGR valve through the shaft/valve interface or from the exhaust manifold and heats the cover member 14 of the actuator 10 before reaching the housing member 12 of the actuator 10.

The present invention is directed to an improved actuator cooling system in which heat is removed from the cover member of the actuator before reaching the housing member and the internal components of the actuator;

Summary of the Invention

The present invention is directed to an actuator which comprises respective housing and cover members including respective internal coolant lines or chambers. Each of the coolant lines or chambers terminates in a pair of ports in the housing and cover members respectively.

In one embodiment, an external line interconnects one of the ports in the housing member with one of the ports in the cover member. In this embodiment, an external coolant input line is adapted for connection to the other one of the ports in the housing member and an external coolant output line is adapted for connection to the other one of the ports in the cover member. In another embodiment, respective external coolant input and output lines are adapted to be connected to the pair of ports in the housing member and cover member respectively.

In one embodiment, each of the coolant chambers includes first and second spaced-apart conduit segments with respective first ends which terminate in the pair of ports in the housing and cover members respectively, and a third conduit segment which extends between and interconnects the second ends of the first and second conduit segments to define respective generally U-shaped coolant chambers.

There are other advantages and features that will be more readily apparent from the following description of the invention, the drawings, and the appended exemplary claims.

Brief Description of the Drawings

In the accompanying drawings that form a part of the specification:

FIGURE 1 is a perspective view of the current design of the cooling system of an actuator; and

FIGURE 2 is a perspective view of one embodiment of an actuator incorporating the cooling system of the present invention.

Detailed Description of the Preferred Embodiment

While this invention is. susceptible to embodiment in many different forms, this specification and the accompanying drawings disclose one form of the subject actuator as an example of the invention. The invention is not intended to be limited to the embodiment so described, however. The scope of the invention is identified in the appended claims.

An actuator 100 in accordance with the present invention is shown in FIGURE 2. Actuator 100, which is of the type disclosed in U.S. Published Patent Application No. US 2010/0301691 , comprises two main components: a housing member 112 and a cover member 114 which is coupled to the housing member 112 and together define an interior cavity or chamber which houses the various elements of the actuator 100 including, for example, the motor, the gears, and the electronics as shown in, for example, U.S. Published Patent Application No. US 2010/0301691. The housing member 112 includes a cooling system 116 defined by an elongate internal cooling chamber or line or conduit 118 which, in the

embodiment shown, is formed as part of and unitary with the casting for the exterior wall of the housing member 112. In the embodiment shown, the conduit 118 terminates in a pair of co-linearly aligned, spaced-apart ports 120 and 122 defined in a top face or wall 124 of the housing member 112.

Although not shown in detail in FIGURE 2, it is understood that the internal cooling conduit 118 is similar to the internal cooling conduit 18 shown in FIGURE 1 and includes a pair of spaced-apart, parallel and generally vertical conduit segments 118a (only one of which is shown in FIGURE 2) having respective upper ends thereof terminating in the respective ports 120 and 122 and a generally horizontal conduit segment (not shown) extending between and joining the lower ends (not shown) of the vertical conduit segments 118a to define a generally U-shaped internal cooling conduit 118.

In accordance with the present invention, the cover member 114 likewise includes a cooling system 126 defined by an elongate internal cooling chamber or line or conduit 128 which, in the embodiment shown, is also formed as part of and unitary with the casting for the exterior wall of the cover member 114. The conduit 128 terminates in a pair of co-linearly aligned, spaced-apart ports 130 and 132 in a top face or wall 134 of the cover member 114.

More specifically, and although not shown in detail in FIGURE 2, it is understood that the internal cooling conduit 128 includes a pair of spaced-apart, parallel and generally vertical conduit segments 128a having respective upper ends thereof terminating in the respective ports 130 and 132 and a generally horizontal conduit segment (not shown) between and joining the lower ends (not shown) of the vertical conduit segments 128a to define a generally U-shaped internal cooling conduit 128 extending through the exterior wall of the cover member 114.

In the embodiment shown, the top face or wall 124 of the housing member 112 and the top face or wall 134 of the cover member 114 are generally co-planar; the port 120 in the top face or wall 124 of the housing member 112 is spaced from, and co-linearly aligned with, the port 130 in the top face or wall 134 of the cover member 114; and the port 122 in the top face or wall 124 of the housing member 112 is spaced from, and co-linearly aligned with, the port 132 in the top face or wall 134 of the cover member 114.

In one embodiment of the present invention as shown in FIGURE 2, a generally U-shaped external line or conduit 140 extends between and includes one end coupled to the port 120 on the housing member 112 and an opposite end coupled to the port 130 on the cover member 114.

Further, in accordance with this embodiment, a first external coolant input or supply line or conduit 121 includes one end coupled to the port 122 of the housing member 112 and a second external coolant output line or conduit 123 includes one end coupled to the port 132 on the cover member 114.

Thus, in accordance with the invention as shown in FIGURE 2, a liquid coolant such as, for example, water or antifreeze and generally designated by the arrow 150 in FIGURE 2, is introduced and enters into the actuator 100 via and through the external input conduit 121 and into the port 122; flows down through the internal conduit 1 18 in the housing member 112 and, more specifically, successively down through the vertical conduit segment 118a thereof, then horizontally through the lower horizontal conduit segment thereof (not shown), and then up through the other vertical conduit segment thereof (not shown), then up through the port 120 into and through the external conduit 140; then into and down through the port 130; then down through the internal line or conduit 128 in the cover member 114 and, more specifically, successively down through the first vertical conduit segment 128a, then horizontally through the lower horizontal conduit segment (not shown), and then upwardly through the second vertical conduit segment 128a; and then the coolant, generally designated by the arrow 152 in FIGURE 2, exits the actuator 100 through the port 132 in the cover member 114 and up through the exterior outlet conduit 123.

Thus, in accordance with the present invention, the incorporation of an internal coolant line or chamber or conduit 128 in the cover member 114 which is coupled to the internal conduit 118 in the housing member 112 advantageously allows heat generated on the cover member 114 side of the actuator 100, such as the heat generated by the gas flowing through an EGR valve coupled to the actuator 100 via a shaft (not shown) extending into the cover member 114, to be removed on the cover member 114 side of the actuator 100 rather than being allowed to flow through the cover member 114 and into the housing member 112 and internal components as in the actuator 10 shown in FIGURE 1.

Numerous variations and modifications of the embodiment described above may be effected without departing from the spirit and scope of the novel features of the invention. It is to be understood that no limitations with respect to the specific cooling system illustrated herein are intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.

For example, it is understood that, in lieu of the external line 140 shown in FIGURE 2, two separate sets of external coolant input and outlet lines or conduits (not shown) can be coupled to the housing member ports 120 and 122 and the cover member ports 130 and 132 respectively to create two separate and independent closed loop cooling systems, i.e., one in the housing member 112 and another in the cover member 114, each including respective cooling systems 116 and 126 and respective internal cooling chambers 118 and 128 identical in structure to those shown in FIGURE 2.