The Benefits of 420 Chrome Stainless Steel Coiled Spring Pins

In applications requiring a combination of high strength, superior fatigue life, and corrosion resistance, 420 martensitic chrome stainless steel offers a host of technical benefits and provides an overall robust cost-effective solution.

Alignment for Clutch Plate in Heavy Equipment

Alignment of components is critical in various powertrain and hydraulic systems. Traditionally Solid OD Ground Dowels have been used to provide the necessary alignment. However, these Ground Dowels require precision machined holes to ensure adequate interference between the Dowel and hole for retention and to keep the insertion force within a practical limit. Precision honing the holes, as compared to simply drilling the holes, results in substantially higher manufacturing costs.

In a large 36” diameter clutch plate there were (24) holes containing a series of (12) ø16mm Solid Ground Dowels and (12) ø10mm size bolts in an alternating pattern around the OD of the plate.
app bushing clutch plate alignment flywheel

Precision honing of holes for solid ground dowels results in higher manufacturing cost

app bushing clutch plate alignment

36" diameter clutch plate

dowel bushing

SPIROL Dowel Bushings improve product quality and reduce manufacturing cost

In an effort to offer cost reductions while maintaining the required alignment, SPIROL recommended that the customer eliminate the (12) precision machined holes that were previously used for the Solid OD Ground Dowels. The remaining (12) holes were simply drilled to the recommended hole size for SPIROL’s standard ø10mm DB100 Dowel Bushing.

The OD of the Dowel Bushing compresses as it is installed into a hole. The spring action of the bushing’s material provides the radial force that keeps it in the hole once installed.

The Dowel Bushing has a hollow ID which allows the bolt to pass through the inside of the bushing after it has been installed thus eliminating the need for separate holes for the Alignment Dowels and bolts. In addition to eliminating (12) of the holes in the assembly, the ability of the Dowel Bushing to conform to a wider tolerance enabled the holes to be opened up from a total manufacturing tolerance of ø0.013mm to ø0.13mm — 10 times wider than the previous tolerance.

Even though the Dowel Bushing is flexible, it has enough rigidity to maintain the required alignment for the assembly. The overall positioning of the clutch plate using the Dowel Bushings performed in the exact same manner as it did with the Solid Ground Dowels which was proven through testing of over 60,000 cycles.

The customer predicted that they saved over $0.21 per dowel, and an additional $0.15 per hole. In total — the customer saved over $4.32 per clutch plate.

Similar solutions have been provided in hydraulic pump applications.

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.