US 12,247,635 B2 · Dual rate torsional coupling

Abstract

Torque is applied to an inner member of a torsional coupling. The first stage (low torque) has a bonded part in series with a set of compression style coil springs. The torsional stiffness of the bonded part is approximately 25% of the resulting torsional stiffness provided by the coil springs. In the second stage (high torque), tangs on the inner member engage with a sprocket plate, transferring torque to the coil springs. The coil springs are held in place by a unique geometry on the sprocket plate and spring holders, which prevent metal-to-metal contact between the coil springs and upper and lower housing portions of the torsional coupling. Surface effect damping occurs at very high torques when the rubber molded around the tangs on the inner member rub on bumps formed on the lower housing portion. A thrust bearing reacts axial forces and eliminates metal-to-metal contact.

A coupling comprising:

a housing comprising:
an upper housing portion having a main body, an opening formed in the main body of the upper housing portion, and a plurality of coil spring receivers positioned circumferentially about and extending away from the main body of the upper housing portion;
a lower housing portion having a main body, an opening formed in the main body of the lower housing portion, and a plurality of coil spring receivers positioned circumferentially about and extending away from the main body of the lower housing portion;
a sprocket plate comprising:
an inner opening formed through a thickness of the sprocket plate;
a plurality of sprocket teeth positioned circumferentially about an inner diameter of the inner opening;
a plurality of engagement recesses, each engagement recess being defined between adjacent sprocket teeth;
and
a plurality of coil spring recesses positioned circumferentially about, and extending radially inwardly from, a perimeter of the sprocket plate;
a tubeform assembly comprising:
an inner member comprising:
a mounting ring at a first longitudinal end of the inner member;
a lower edge at a second longitudinal end of the inner member;
a bonding element in a form of an outer wall between the mounting ring and the lower edge;
a plurality of tangs attached to, and extending away from, the lower edge, the plurality of tangs positioned circumferentially around the lower edge,
an outer member comprising:
a bonding ring in a form of an outer wall that is substantially concentrically positioned about the bonding element of the inner member;
and
a flange extending away from the bonding ring, the outer member being rigidly secured to the sprocket plate via the flange;
and
a tubeform comprising an elastomeric material, wherein the tubeform is between the bonding ring of the outer member and the bonding element of the inner member;
wherein the tubeform assembly is positioned, relative to the sprocket plate, such that each of the plurality of tangs is positioned within a corresponding one of the plurality of engagement recesses;
and
a plurality of coil spring assemblies, each comprising:
an outer coil spring having a first end and a second end;
and
at least two coil spring holders, one of which is positioned at the first end of the outer coil spring and another of which is positioned at the second end of the outer coil spring;
wherein each of the plurality of coil spring assemblies is positioned within a corresponding one of the plurality of coil spring recesses of the sprocket plate, such that the plurality of coil spring assemblies and the sprocket plate form a sprocket assembly;
wherein the tubeform assembly is positioned on a first side of the sprocket assembly and secured to the sprocket plate;
wherein the upper housing portion is positioned on a first side of the sprocket assembly and disposed about the tubeform assembly;
and
wherein the lower housing portion is positioned on a second side of the sprocket assembly, opposite the first side of the sprocket assembly.

29 more elements

Dual rate torsional coupling

Life of this patent

Dual rate torsional coupling

Life of this patent

Abstract

Claims20