Locating an Automotive Transmission Case to the Engine

An OEM was using a 16mm OD Ground Solid Dowel to locate the transmission to the back of the engine. Specified tolerance for alignment had the components be within 20 microns of alignment. This particular application was more demanding than most due to the weight of the two components to be aligned, and the somewhat erratic method of bringing these components together. The customer used manual guided hoists that result in the possibility of damage to the dowel, and or irregular forces that could cause the components to be misaligned. The customer approached SPIROL for cost-reduction suggestions.
app gd100 auto transmission case product
SPIROL Series GD100 Ground Hollow Dowel
app gd100 auto transmission case
app gd100 auto transmission case close up
SPIROL's initial investigation was to determine if the lowest cost solution would work, a standard SPIROL Spring Dowel. Upon testing and review it was determined that although this was the lowest cost, the overall alignment in this application was in the 60 micron tolerance range. The thin wall of this product also was susceptible to possible damage from the two heavy components being brought together in a somewhat erratic method.

SPIROL then approached the application using the standard Series GD100 Ground Hollow Dowels. These are heavy wall, precision ground products that offer a more rigid configuration and are more robust, which is better suited to the style of assembly used. The OD ground, butted seam dowel met the current specification for a hole size of 15.985/16.000 mm that was in the component and was easily incorporated into existing installation fixtures and equipment. The customer was able to attain a 30% cost savings on the program, and was able to easily transition to the design change as assembly equipment for the dowel needed little to no alteration. The function of the assembly remained consistent with the previous product.

SPIROL's value originated from the roll forming process where parts are fabricated from roll formed strip steel with little to no scrap or shavings. This process is usually 50% to 75% faster than machining and about equal to cold heading. The hollow dowel uses less material than the solid dowel, allowing further cost savings and overall vehicle weight savings. This value is then passed on to the customer in an effort to make them more competitive.

Need help finding the right solution?

SPIROL offers complimentary Application Engineering support. We will assist on new designs as well as help resolve issues, and recommend cost savings on existing designs.