Patent Application
20100154188
The invention relates to heat exchanger assemblies, particularly to a method for temporarily securing a bracket to a heat exchanger until the bracket is permanently brazed to the heat exchanger.
Heat exchangers commonly require mounting brackets to be attached to the end manifolds and/or to the side reinforcement channels. There are several methods currently used to attach the brackets. In some cases the bracket is brazed to the heat exchanger; in other cases the bracket is attached after the brazing process. When the bracket is to be brazed to the heat exchanger, it is necessary to temporarily secure the bracket in place to the heat exchanger until the brazing process is completed.
A first known method of securing a bracket to a heat exchanger is to use screws to attach the bracket. Screws are costly and time consuming to drive. Screw attachment is normally used after the brazing process, and the screwed joint must withstand all of the applied stresses to the bracket and heat exchanger over the lifetime of the assembly.
A second known method of securing a bracket is to braze the bracket to the heat exchanger, using special fixtures to clamp the bracket to the heat exchanger through the brazing process. This method requires model-specific clamping fixtures that may be very costly.
A third known method of securing a bracket is to fixture and spot weld the bracket to the heat exchanger before brazing. This method may alter the material properties of the bracket and/or the heat exchanger, and requires skilled welding operators to affix the bracket to the heat exchanger without damaging the heat exchanger.
A fourth known method of securing a bracket to a heat exchanger is to first skive tabs into the heat exchanger, then place the bracket on the heat exchanger in the proper location relative to the skived tabs, and subsequently clinch the tabs onto the bracket to hold the assembly in place through a brazing operation. While this method can provide a self-fixtured assembly to the brazing process, it still has several associated drawbacks. Skiving is done relatively early in the process, and results in the necessity to handle a part with the skived tabs exposed. This leaves the tabs subject to damage in subsequent handling. The bracket needs to be placed over the tabs without bending or breaking the tabs, which requires adequate clearance between the bracket and the tabs as well as precise positioning of the bracket over the tabs. The requirement for adequate clearance between the bracket and the tabs results in the potential for more variation in the final location of the bracket on the heat exchanger. Additional machines and operations are required to skive the tabs, properly position the bracket over the tabs, and clinch the skived tabs to secure the joint.
What is desired is an improved method to retain a bracket to a heat exchanger until the bracket can be permanently affixed to the heat exchanger by brazing.
The present invention is a method for attaching a bracket to a heat exchanger. In accordance with this method, a heat exchanger having a surface to which the bracket is to be mounted is provided. A bracket is placed in contact with the mounting surface at a desired mounting location. The bracket has an edge portion that conforms to the mounting surface. A subsequent operation performed with the bracket in place skives a portion of the mounting surface adjacent to the edge portion of the bracket, deforming the skived material against the edge portion of the bracket. The skived material acts to retain the bracket in place on the heat exchanger until the bracket and heat exchanger assembly can be brazed to form a permanent connection.
This invention will be further described with reference to the accompanying drawings in which:
In accordance with an exemplary embodiment of this invention, referring to
Still referring to
At step 130 of
Upon completion of the skiving step 130, the heat exchanger 10 and bracket 12 comprise a skived heat exchanger/bracket assembly 14. The skived heat exchanger/bracket assembly 14 is retained sufficiently to maintain the bracket 12 to the heat exchanger 10 without the need for external fixturing 20 until brazing can be completed.
At step 140 in
It is noted that the term “heat exchanger” as it applies to this method is not limited to a complete heat exchanger assembly, but may refer to a component of a complete heat exchanger assembly. For example, it may be preferred to mount a bracket to a manifold tank by skiving a portion of a mounting surface on the manifold tank according to the method of this invention before assembling the manifold tank to a heat exchanger core portion. Additionally, it is noted that the brazing operation described in step 140 of the description above may be used to concurrently braze manifold tanks to a core portion while brazing the bracket 12 to the heat exchanger.
As described above, the method of this invention includes skiving a portion of the mounting surface of the heat exchanger 10 adjacent to an edge portion of the bracket 12 so that a sufficient amount of the skived material is deformed against the edge portion to retain the bracket 12 to the heat exchanger 10. One way to accomplish this is with the edge portion comprising a portion of a peripheral edge of the bracket. In order to achieve sufficient retention of bracket 12 to heat exchanger 10, this may require skiving material from the mounting surface toward opposing peripheral edges of the bracket in two opposing directions to trap bracket 12 in place. Skiving in two opposing directions is more complex than a single direction skiving operation, and may require more complex equipment and/or additional handling of the heat exchanger/bracket assembly.
The embodiment of this invention depicted in
While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow.
