Isolator with dual springs

Patent metadata

Field	Value
Publication number	US-2016265643-A1
Application number	US-201415035688-A
Country	US
Kind code	A1
Filing date	Nov 10, 2014
Priority date	Nov 10, 2013
Publication date	Sep 15, 2016
Grant date	—

Abstract

In an aspect, an isolator is provided, comprising a hub, a pulley, an isolation spring and a transition spring. The hub defines an axis and is connectable to a rotatable shaft of a rotary device. The pulley is rotatably mounted to the hub. The isolation spring and transition spring act in series in a torque path between the pulley and the hub. The isolation spring has a first spring rate. The transition spring has a second spring rate that is lower than the first spring rate.

First claim

1 . An isolator, comprising:
a hub defining an axis and connectable to a rotatable shaft of a rotary device; a pulley that is rotatably mounted to the hub; and an isolation spring and a transition spring that act in series in a torque path between the pulley and the hub, wherein the isolation spring has a first spring rate, and the transition spring has a second spring rate that is lower than the first spring rate.

2 . An isolator as claimed in claim 1 , wherein the intermediate member at least partially encloses the isolation spring to prevent direct contact between the isolation spring and the pulley.

3 . An isolator as claimed in claim 1 , wherein the isolation spring is positioned between the hub and an intermediate member and wherein the transition spring is positioned between the intermediate member and the pulley.

4 . An isolator as claimed in claim 1 , wherein the isolation spring is one of a plurality of isolation springs positioned in parallel with one another and the transition spring is one of a plurality of transition springs positioned in parallel with one another and in series with the isolation springs.

5 . An isolator as claimed in claim 1 , wherein the plurality of isolation springs include outer springs and inner springs nested within the outer springs.

6 . An isolator as claimed in claim 1 , further comprising a first transition spring torque limit surface and a second transition spring torque limit surface, wherein the first and second transition spring torque limit surfaces engage one another to limit compression of the transition spring during movement of the hub and the pulley relative to one another.

7 . An isolator as claimed in claim 6 , further comprising a first isolation spring torque limit surface and a second isolation spring torque limit surface, wherein the first and second isolation spring torque limit surfaces engage one another to limit compression of the isolation spring during movement of the hub and the pulley relative to one another.

8 . An isolator as claimed in claim 6 , wherein the first transition spring torque limit surface is one of a plurality of first transition spring torque limit surfaces and wherein the second transition spring torque limit surface is one of a plurality of second transition spring torque limit surfaces, and wherein the first and second transition spring torque limit surfaces are positioned to engage one another after a first amount of movement of the transition spring during torque transfer in a first direction between the hub and pulley, and the first and second transition spring torque limit surfaces are positioned to engage one another after a second amount of movement of the transition spring this is smaller than the first amount of movement, during torque transfer in a second direction between the hub and pulley.

9 . An isolator as claimed in claim 1 , further comprising a bushing having selected frictional properties positioned between the hub and the pulley.

10 . An isolator as claimed in claim 1 , further comprising a seal member having a first lip engaged with the pulley and a second lip engaged with the hub, wherein the first and second lips face an interior chamber of the isolator and are urged against the pulley and the hub respectively by pressure in the interior chamber during operation of the isolator.

11 . An isolator as claimed in claim 1 , wherein the first spring rate is less than about 1 Nm/degree, and the second spring rate is between about 3 and 5 Nm/degree.

12 . An isolator as claimed in claim 1 , wherein the transition spring is a helical torsion spring.

13 . An isolator, comprising:
a hub defining an axis; a pulley that is rotatably mounted to the hub; an isolation spring and a transition spring that act in series in a torque path between the pulley and the hub, wherein the isolation spring has a first spring rate, and the transition spring has a second spring rate, and wherein, throughout a first range of relative movement between the hub and the pulley away from a home position, the effective spring rate of the isolator is the series sum of the first and second spring rates, and throughout a second range of relative movement beyond the first range of relative movement between the hub and the pulley away from the home position, the effective spring rate of the isolator is the first spring rate.

Assignees

• Litens Automotive Inc

Inventors

• Dell James W
• Replete Boris

Classifications

• F02B67/06

  driven by means of chains, belts, or like endless members · CPC title

• F16H2055/366

  with means providing resilience or vibration damping · CPC title

• F16H55/36 Primary

  Pulleys (with features essential for adjustment F16H55/52) · CPC title

• F16D3/66

  the elements being metallic, e.g. in the form of coils · CPC title

• F16F15/123

  Wound springs {(F16F15/1213, F16F15/1216, F16F15/127 take precedence)} · CPC title