Dual piston actuator

Patent metadata

Field	Value
Publication number	US-2016108972-A1
Application number	US-201414516026-A
Country	US
Kind code	A1
Filing date	Oct 16, 2014
Priority date	Oct 16, 2014
Publication date	Apr 21, 2016
Grant date	—

Abstract

A power transmitting component can include a friction clutch, hydraulic ram, and an actuator. The actuator can include first and second pistons, and a resilient member. The resilient member can translate the first piston to provide a high volume of fluid at low pressure to the ram when a pressure in a first chamber is less than a predetermined pressure and the second piston is translated in a first direction. The resilient member can compress between the first and second pistons to permit relative motion between the pistons when the pressure is equal to, or greater than, the predetermined pressure and the second piston is translated in the first direction. The second piston provides a low volume of fluid at high pressure to the ram when pressure in the first chamber is equal to, or greater than, the predetermined pressure and the second piston is translated in the first direction.

First claim

What is claimed is:

1 . A power transmitting component comprising:
a friction clutch having a plurality of first clutch plates and a plurality of second clutch plates that are interleaved with the first clutch plates; a hydraulic ram coupled to the friction clutch, the hydraulic ram having a ram chamber and a ram piston that is movable in the ram chamber between a first ram position in which the ram piston is retracted relative to the first and second clutch plates, and a second ram position in which the ram piston is extended toward the first and second clutch plates to a greater extent than when the ram piston is in the first position; and an actuator including:
a first piston and cylinder, the first piston being received in the first cylinder, the first piston and cylinder defining a first chamber;
a second piston and cylinder, the second piston being received in the second cylinder, the second piston and cylinder defining a second chamber in fluid communication with the ram chamber, the second piston defining a fluid passage fluidly coupling the first and second chambers;
a valve body being movable between a first valve position wherein the fluid passage is open to permit fluid communication between the first and second chambers, and a second valve position wherein the valve body blocks the fluid passage to prevent fluid communication between the first and second chambers; and
a drive mechanism configured to axially translate the second piston, and configured to axially translate the first piston when a pressure in the first chamber is less than a predetermined pressure and not translate the first piston when the pressure in the first chamber is equal to, or greater than, the predetermined pressure;
wherein the valve body is prevented from moving to the second valve position and the first piston provides a first volume of fluid at a first pressure to the ram chamber when the drive mechanism translates the first piston in a first axial direction; wherein the valve body is permitted to move to the second valve position when the pressure in the first chamber is equal to, or greater than the predetermined pressure and the second piston is translated in the first axial direction; wherein the second piston provides a second volume of fluid at a second pressure to the ram chamber, the first volume of fluid being greater than the second volume of fluid, and the first pressure being less than the second pressure, when the valve body is in the second valve position and the second piston is translated in the first axial direction.

2 . The power transmitting component of claim 1 , wherein the drive mechanism includes a lead screw being rotatable about an axis and having a plurality of threads, wherein the second piston has a plurality of mating threads, the threads and mating threads being configured to cooperate to axially translate the second piston when the lead screw is rotated about the axis.

3 . The power transmitting component of claim 2 , wherein the drive mechanism includes a resilient member, the resilient member having a first end coupled for axial translation with the second piston, and a second end coupled for axial translation with the first piston, and wherein the resilient member is configured to translate the first piston when the pressure in the first chamber is less than the predetermined pressure and the second piston is axially translated, and is configured to compress between the first and second pistons to permit relative axial motion between the first and second pistons when the pressure in the first chamber is equal to, or greater than, the predetermined pressure and the second piston is translated in the first axial direction.

4 . The power transmitting component of claim 1 , wherein the first piston is configured to engage the valve body to prevent the valve body from moving to the second valve position when the first piston is in a first position relative to the second piston, and the valve body is permitted to move to the second valve position when the first piston is in a second position relative to the second piston.

5 . The power transmitting component of claim 4 , wherein the valve body includes a sealing member, a control member, the sealing member being configured to mate with a first side of the second piston proximate to the second chamber to seal the fluid passage, the control member extending from the sealing member, through the fluid passage, to a second side of the second piston proximate to the first chamber, the control member being configured to engage the first piston proximate to the second side of the second piston.

6 . The power transmitting component of claim 1 , wherein the first piston is an annular shape defining a central bore and the second piston extends through the central bore.

7 . The power transmitting component of claim 1 , wherein the first chamber is fluidly coupled to a fluid reservoir.

8 . A power transmitting component comprising:
a friction clutch having a plurality of first clutch plates and a plurality of second clutch plates that are interleaved with the first clutch plates; a hydraulic ram coupled to the friction clutch, the hydraulic ram having a ram chamber and a ram piston that is movable in the ram chamber between a first position in which the ram piston is retracted relative to the first and second clutch plates, and a second position in which the ram piston is extended toward the first and second clutch plates to a greater extent than when the ram piston is in the first position; and an actuator including:
a housing having a first cylinder and a second cylinder disposed about an axis;
a first piston received in the first cylinder, the first piston and first cylinder defining a first fluid chamber;
a second piston received in the second cylinder, the second piston and second cylinder defining a second fluid chamber in fluid communication with the ram chamber; and
a resilient member having a first end coupled for axial translation with the second piston, and a second end coupled for axial translation with the first piston;
wherein the resilient member is configured to translate the first piston to provide a first volume of fluid at a first pressure to the ram chamber when a pressure in the first chamber is less than a predetermined pressure and the second piston is translated in the second cylinder in a first axial direction, and wherein the resilient member is configured to compress between the first and second pistons to permit relative axial motion between the first and second pistons when the pressure in the first chamber is equal to, or greater than, the predetermined pressure and the second piston is translated in the first axial direction; wherein the second piston provides a second volume of fluid at a second pressure to the ram chamber when the pressure in the first chamber is equal to, or greater than, the predetermined pressure and the second piston is translated in the first axial direction, the first volume of fluid being greater than the second volume of fluid, and the first pressure being less than the second pressure.

9 . The power transmitting component of claim 8 , wherein the actuator further includes a lead screw being rotatable about the axis, and having a plurality of threads, wherein the second piston has a plurality of mating threads, the threads and mating threads being configured to cooperate to axially translate the second piston when the lead screw is rotated about the axis.

10 . The power transmitting component of claim 8 , wherein the actuator includes a valve, the valve having a fluid passage and a valve body, the fluid passage fluidly coupling the first and second chambers, the valve body bein

Assignees

• American Axle & Mfg Inc

Inventors

• Downs James P
• Valente Paul J

Classifications

• F16D48/02 Primary

  Control by fluid pressure · CPC title

• F16D25/083 Primary

  Actuators therefor (F16D25/085 - F16D25/087 take precedence) · CPC title

• F16D2121/02

  Fluid pressure · CPC title

• F16D2048/0212

  Details of pistons for primary or secondary cylinders especially adapted for fluid control · CPC title

• F16D48/06

  Control by electric or electronic means, e.g. of fluid pressure · CPC title