Method of forming a drive surface on an eccentric pin

Details Method of forming a drive surface on an eccentric pin Method of forming a drive surface on an eccentric pin

1999-09-24

2001-03-20

Briggs, William (Department: 3722)

Gear cutting, milling, or planing

Broaching

Process

Reexamination Certificate

active

06203257

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to an eccentric pin on a scroll compressor drive shaft, and more specifically, to a method of forming a drive surface on the eccentric pin.
Scroll compressors utilize drive shafts that have an end with an eccentric pin, which is displaced from the rotational axis of the drive shaft. The eccentric pin is received within a bore in a slider block which is, in turn, received within a portion of an orbiting scroll, as is well know in the art. During rotation of the drive shaft, the eccentric pin engages the slider block and moves the orbiting scroll through an orbital path.
The eccentric pin has a generally cylindrical outer surface with a drive surface formed along the length of a portion of the outer surface. The drive surface is generally flat with a slight crown in the middle for providing single line contact with the slider block. The drive surface must have a relatively smooth surface finish to minimize the friction between the eccentric pin and the slider block. Previously, to form the drive surface the drive shaft had to be moved to a first machining operation where a flat was broached onto the eccentric pin. Next, the drive shaft had to be moved to a second machining operation where the crown was then formed on the flat by a finish grinding operation, which also provided the desired surface finish. Forming a drive surface with a crown in two separate operations resulted in increased labor and tooling costs. Therefore, what is needed is a more efficient method of forming a finished drive surface with a crown.
SUMMARY OF THE INVENTION AND ADVANTAGES
The present invention provides a method of forming a drive surface on an eccentric pin of a drive shaft for a scroll-type compressor. First, an eccentric pin having an axis and a generally cylindrical outer surface disposed radially about the axis is provided. Next, a broaching tool having a machining face with a contour is provided. The contour may be a concave shallow bell-shaped curve. Finally, the drive surface is formed by engaging the outer surface with the machining face transverse to the axis. In this manner, the machining face forms a shape complementary to the contour on the eccentric pin thereby forming a slight crown on the drive surface. The broaching tool produces an adequate surface finish so that no subsequent machining operations to the drive surface are necessary.
Accordingly, the above provides a more efficient method of forming a finished drive surface with a crown.


REFERENCES:
patent: 2511912 (1950-06-01), George
patent: 3825992 (1974-07-01), Troeger
patent: 4108577 (1978-08-01), Brucken et al.

Affiliated with

Also associated with

Rating

Method of forming a drive surface on an eccentric pin does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of forming a drive surface on an eccentric pin, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of forming a drive surface on an eccentric pin will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2464205