Nippon Light Metal has been granted a patent for a method to manufacture a liquid-cooled jacket. The method involves friction stirring to join a jacket body and a sealing body, reducing the size of a recessed groove and improving the surface smoothness. The method utilizes a main joining rotary tool with different taper angles and a stairs-like pin step portion. GlobalData’s report on Nippon Light Metal gives a 360-degree view of the company including its patenting strategy. Buy the report here.
According to GlobalData’s company profile on Nippon Light Metal, UAV battery thermal mgmt was a key innovation area identified from patents. Nippon Light Metal's grant share as of June 2023 was 1%. Grant share is based on the ratio of number of grants to total number of patents.
Method for manufacturing a liquid-cooled jacket using friction stirring
A recently granted patent (Publication Number: US11654508B2) describes a method for manufacturing a liquid-cooled jacket. The jacket consists of a jacket body with a bottom portion, a peripheral wall portion, and a support column, as well as a sealing body that seals the opening of the jacket body. The method involves several steps, including the preparation of a peripheral wall step portion and a support column end surface at the same height position, the placement of the sealing body on the jacket body, and two main joining steps using friction stirring.
In the first main joining step, a rotary tool is used to perform friction stirring along the abutted portion between the peripheral wall step portion and the sealing body. In the second main joining step, friction stirring is performed at the overlapping portion between the support column end surface and the back surface of the sealing body. The rotary tool used for friction stirring has a base-end-side pin and a tip-end-side pin, with a taper angle of the base-end-side pin being greater than that of the tip-end-side pin. The base-end-side pin also has a pin step portion on its outer circumferential surface, while the tip-end-side pin has a spiral groove formed by a spiral bottom surface and a spiral side surface.
The method also includes a provisional joining step before the first main joining step, where the abutted portion is provisionally joined. The preparation step involves forming the jacket body by die casting, with the bottom portion and the sealing body both being convex toward the front surface. The deformation amount of the jacket body is measured in advance, and the insertion depth of the rotary tool is adjusted accordingly during the main joining steps.
Additionally, the method incorporates cooling elements into the jacket. A cooling plate with a cooling flow passage is placed on the back surface of the bottom portion, and the friction stirring is performed while the jacket body and the sealing body are cooled. The cooling flow passage can have a planar shape that follows the moving trajectory of the rotary tool. The cooling flow passage is composed of a cooling pipe embedded in the cooling plate.
Overall, this patented method provides a detailed process for manufacturing a liquid-cooled jacket using friction stirring and incorporating cooling elements. The method ensures secure joining of the jacket body and the sealing body while maintaining proper cooling for the jacket.
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