Brake torque limiter

• US 4,296,897 A
• Filed: 01/22/1979
• Issued: 10/27/1981
• Est. Priority Date: 01/22/1979
• Status: Expired due to Term

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Thompson, Bernard B.
• Primary Examiner(s): Barefoot, Galen L.
• Application Number:
  US06/005,253
• Time in Patent Office: 1,009 Days
• Field of Search: 244/111, 188/134, 188/181 T, 188/195, 303/22 R, 303/112
• US Class Current: 244/111
• CPC Class Codes: B60T 11/34 Pressure reducing or limiting valves for arrangements for adjusting wheel-braking force responsive to vehicle weight or load B60T8/1831
• CPC Class Codes: B64C 25/46 Brake regulators for preventing skidding or aircraft somersaulting
• CPC Class Codes: F16D 2055/0058 Fully lined, i.e. braking surface extending over the entire disc circumference
• CPC Class Codes: F16D 2127/08 Self-amplifying or de-amplifying mechanisms
• CPC Class Codes: F16D 55/40 actuated by a fluid-pressure device arranged in or one the brake

Abstract

A brake system wherein a manually operated foot pedal actuates a metering valve that controls the pressure magnitude of fluid applied to a set of main brake pistons which push stator brake plates against rotating brake plates resulting in wheel braking torque; and further wherein a force balanced piston and a control valve, modulates the fluid pressure applied to the set of main brake pistons in response to wheel braking torque reaction, such that maximum brake torque is limited in direct proportion to the magnitude of pressure metered.

Claims

1. A torque responsive brake control apparatus for controlling a fluid pressure operated brake mechanism, operatively connected to a rotatable member, comprising:

said fluid pressure operated brake mechanism being mounted substantially coaxial with said rotatable member and adapted for exerting a braking force to resist rotation of said rotatable member;

a metering valve being manually operated for controlling a flow of pressurized fluid to said brake mechanism;

a torque arm connected to said brake mechanism;

said torque arm being angularly movable in response to brake reaction torque associated with said rotatable member when a braking force is applied to resist rotation of said rotatable member;

said torque responsive control apparatus having a brake rod assembly attached at one end to said torque arm and attached at an opposite end to a fixed support;

said brake rod assembly being arranged between said torque arm and said fixed support, for resisting angular displacement of said torque arm;

a brake torque limiter incorporated within said brake rod assembly and being interposed in the fluid circuit between said manually operated metering valve and said brake mechanism, for controlling the supply and release of fluid under pressure to and from said brake mechanism;

said brake torque limiter comprising a cylinder head section with a dual-diameter internally stepped cylinder section, and a matching dual-diameter stepped piston slidably mounted therein;

said brake rod assembly comprising a first brake rod segment fixedly attached to said dual-diameter stepped piston, and a second brake rod segment fixedly attached to said dual-diameter stepped cylinder and head section of said brake torque limiter;

a first chamber formed between said cylinder head section and said dual-diameter stepped piston;

said brake torque limiter being constructed and arranged with respect to said brake rod assembly, so as to normally bias said brake rod assembly in one direction of extending said brake rod assembly to its maximum overall length, by directing fluid pressure from said manually operated metering valve into said first chamber, and in the opposite direction for decreasing the overall length of said brake rod assembly by torque resulting from application of brakes;

a control valve incorporated within said brake torque limiter and interposed in the fluid circuit through which fluid under pressure from said manually operated metering valve, is supplied to the brake mechanism;

said control valve being normally in an open position, when said brake rod assembly is at its maximum overall length, for circulating fluid pressure from said metering valve through said control valve to said brake mechanism;

said control valve being actuated to a closed position, when said brake rod assembly is decreased from its maximum overall length by predetermined excessive braking torque of said rotatable member, for blocking fluid flow between said brake mechanism and said manually operated metering valve, and for trapping metered fluid pressure between said brake torque limiter and said brake mechanism;

a second chamber formed between said step sections of the dual-diameter piston and matching internal dual-diameter cylinder, for creating an expanding annulus volume in response to contraction of the overall length of said brake rod assembly, to receive hydraulic fluid trapped between said brake torque limiter and said brake mechanism, and thereby decrease the pressure of said trapped hydraulic fluid resulting in a decrease in the ratio of brake torque reaction relative to metered hydraulic pressure.

2. A torque responsive brake control apparatus for controlling a fluid pressure operated brake mechanism, operatively connected to a rotatable member, comprising:

said fluid pressure operated brake mechanism being mounted substantially coaxial with said rotatable member and adapted for exerting a braking force to resist rotation of said rotatable member;

a metering valve being manually operated for controlling a flow of pressurized fluid to said brake mechanism;

a torque arm connected to said brake mechanism;

said torque arm being angularly movable in response to brake reaction torque associated with said rotatable member when a braking force is applied to resist rotation of said rotatable member;

said torque responsive control apparatus having a brake rod assembly attached at one end to said torque arm and attached at an opposite end to a fixed support;

said brake rod assembly being arranged between said torque arm and said fixed support, for resisting angular displacement of said torque arm;

a brake torque limiter incorporated within said brake rod assembly and being interposed in the fluid circuit between said manually operated metering valve and said brake mechanism, for controlling the supply and release of fluid under pressure to and from said brake mechanism;

said brake torque limiter comprising a cylinder head section with a dual-diameter internally stepped cylinder section, and a matching dual-diameter stepped piston slidably mounted therein;

said brake rod assembly comprising a first brake rod segment fixedly attached to said dual-diameter stepped piston, and a second brake rod segment fixedly attached to said dual-diameter stepped cylinder and head section of said brake torque limiter;

a first chamber formed between said cylinder head section and said dual-diameter stepped piston;

said brake torque limiter being constructed and arranged with respect to said brake rod assembly, so as to normally bias said brake rod assembly in one direction of contracting said brake rod assembly to its minimum overall length, by directing fluid pressure from said manually operated metering valve into said first chamber, and in the opposite direction for increasing the overall length of said brake rod assembly by torque resulting from application of brakes;

a control valve incorporated within said brake torque limiter and interposed in the fluid circuit through which fluid under pressure from said manually operated metering valve, is supplied to the brake mechanism;

said control valve being normally in an open position, when said brake rod assembly is at its minimum overall length, for circulating fluid pressure from said metering valve through said control valve to said brake mechanism;

said control valve being actuated to a closed position, when said brake rod assembly is increased from its minimum overall length by predetermined excessive braking torque of said rotatable member, for blocking fluid flow between said brake mechanism and said manually operated metering valve, and for trapping metered fluid pressure between said brake torque limiter and said brake mechanism;

a second chamber formed between said step sections of the dual-diameter piston and matching internal dual-diameter cylinder, for creating an expanding annulus volume in response to extension of the overall length of said brake rod assembly, to receive hydraulic fluid trapped between said brake torque limiter and said brake mechanism, and thereby decrease the pressure of said trapped hydraulic fluid resulting in a decrease in the ratio of brake torque reaction relative to metered hydraulic pressure.

3. An individual wheel torque responsive brake control apparatus for controlling a fluid pressure operated brake mechanism mounted substantially coaxial with a vehicle wheel in rolling contact with the ground, said apparatus comprising:

a metering valve being manually operated for controlling flow of pressurized fluid to said brake mechanism;

a torque arm connected to said brake mechanism and being angularly movable in response to brake reaction torque, associated with frictional adhesion between said vehicle wheel and the ground, when a braking force is applied to resist rotation of said wheel;

a brake rod assembly attached at one end to said torque arm and attached at an opposite end to fixed support structure of said vehicle wheel, for resisting angular displacement of said torque arm;

a brake torque limiter incorporated within said brake rod assembly and being interposed in the fluid circuit between said manually operated metering valve and said brake mechanism, for controlling the supply and release of fluid under pressure to and from said brake mechanism;

said brake torque limiter comprising a cylinder head section with a dual-diameter internally stepped cylinder section, and a matching dual-diameter stepped piston slidably mounted therein;

said brake rod assembly comprising a first brake rod segment fixedly attachd to said dual-diameter stepped piston, and a second brake rod segment fixedly attached to said dual-diameter stepped cylinder and head section of said brake torque limiter;

a first chamber formed between said cylinder head section and said dual-diameter stepped piston;

said brake torque limiter being constructed and arranged with respect to said brake rod assembly, so as to normally bias said brake rod assembly in one direction by directing fluid pressure from said manually operated metering valve into said first chamber, to extend in overall length said brake rod assembly, and in the opposite direction by reaction torque, associated with frictional adhesion between said vehicle wheel and the ground resulting from application of brakes, to contract said brake rod assembly;

a control valve incorporated within said brake torque limiter and interposed in the fluid circuit through which fluid under pressure, from said manually operated metering valve, is supplied to the brake mechanism;

said control valve being normally in an open position, when said brake rod assembly is at a fully extended operative position, for circulating fluid pressure from said metering valve through said control valve to said brake mechanism;

said control valve being actuated to a closed position when said brake rod assembly is retracted from said fully extended operative position by a predetermined excessive braking torque of said vehicle wheel, for blocking fluid flow between said brake mechanism and said manually operated metering valve, and for trapping metered fluid pressure between said brake torque limiter and said brake mechanism; and

a second chamber formed between said step sections of the dual-diameter piston and matching internal dual-diameter cylinder, for creating an expanding annulus volume in response to contraction of the overall length of said brake rod assembly, for occupation by fluid pressure trapped between said brake torque limiter and said brake mechanism, to decrease pressure of said trapped fluid and thereby lower the amount of brake torque reaction relative to metered fluid pressure.

4. An individual wheel torque responsive brake control apparatus for controlling a fluid pressure operated brake mechanism mounted substantially coaxial with a vehicle wheel in rolling contact with the ground, said apparatus comprising:

a metering valve being manually operated for controlling flow of pressurized fluid to said brake mechanism;

a torque arm connected to said brake mechanism and being angularly movable in response to brake reaction torque, associated with frictional adhesion between said vehicle wheel and the ground, when a braking force is applied to resist rotation of said wheel;

a brake rod assembly attached at one end to said torque arm and attached at an opposite end to fixed support structure of said vehicle wheel, for resisting angular displacement of said torque arm;

a brake torque limiter incorporated within said brake rod assembly and being interposed in the fluid circuit between said manually operated metering valve and said brake mechanism, for controlling the supply and release of fluid under pressure to and from said brake mechanism;

said brake torque limiter comprising a cylinder head section with a dual-diameter internally stepped cylinder section, and a matching dual-diameter stepped piston slidably mounted therein;

said brake rod assembly comprising a first brake rod segment fixedly attached to said dual-diameter stepped piston, and a second brake rod segment fixedly attached to said dual-daimeter stepped cylinder and head section of said brake torque limiter;

a first chamber formed between said cylinder head section and said dual-diameter stepped piston;

said brake torque limiter being constructed and arranged with respect to said brake rod assembly, so as to normally bias said brake rod assembly in one direction by directing fluid pressure from said manually operated metering valve into said first chamber, to contract in overall length said brake rod assembly, and in the opposite direction by reaction torque, associated with frictional adhesion between said vehicle wheel and the ground resulting from application of brakes, to extend said brake rod assembly;

a control valve incorporated within said brake torque limiter and interposed in the fluid circuit through which fluid under pressure, from said manually operated metering valve, is supplied to the brake mechanism;

said control valve being normally in an open position, when said brake rod assembly is at a fully retracted operative position, for circulating fluid pressure from said metering valve through said control valve to said brake mechanism;

said control valve being actuated to a closed position when said brake rod assembly is extended from said fully contracted operative position by a predetermined excessive braking torque of said vehicle wheel, for blocking fluid flow between said brake mechanism and said manually operated metering valve, and for trapping metered fluid pressure between said brake torque limiter and said brake mechanism; and

a second chamber formed between said step sections of the dual-diameter piston and matching internal dual-diameter cylinder, for creating an expanding annulus volume in response to extension of the overall length of said brake rod assembly, for occupation by fluid pressure trapped between said brake torque limiter and said brake mechanism, to decrease pressure of said trapped fluid and thereby lower the amount of brake torque reaction relative to metered fluid pressure.

5. An individual aircraft wheel torque responsive brake control apparatus for controlling a hydraulically actuated aircraft wheel disc brake assembly having a housing mounted substantially coaxial with a wheel axle of a landing gear strut and rotatable relative thereto, said apparatus comprising:

a metering valve being pilot operated for controlling flow of hydraulic pressure to said disc brake assembly;

a torque arm fixedly attached to said disc brake assembly housing and being angularly movable therewith about said wheel axle, in response to braking reaction torque, associated with frictional adhesion between an aircraft wheel and runway surface, when a braking force is applied to resist rotation of said aircraft wheel;

a brake rod assembly connected at one end to said torque arm and connected at an opposite end to the landing gear strut, for resisting angular displacement of said torque arm and for transmitting braking torque reaction force from said disc brake assembly housing to said landing gear strut;

a brake torque limiter incorporated within said brake rod assembly and being interposed in a hydraulic circuit between said pilot operated metering valve and said disc brake assembly, for controlling the supply and release of hydraulic pressure to and from said disc brake assembly;

said brake torque limiter comprising a cylinder head section with a dual-diameter internally stepped cylinder section, and a matching dual-diameter stepped piston slidably mounted therein;

said brake rod assembly comprising a first brake rod segment fixedly attached to said dual-diameter stepped piston, and a second brake rod segment fixedly attached to said dual-diameter stepped cylinder and head section of said brake torque limiter;

a first chamber formed between said cylinder head section and said dual-diameter stepped piston;

said brake torque limiter being constructed and arranged with respect to said brake rod assembly, so as to normally bias said brake rod assembly in one direction to extend in overall length by directing hydraulic pressure from said pilot operated metering valve into said first chamber, and in the opposite direction to contract said brake rod assembly by reaction torque generated by frictional adhesion between the aircraft wheel and runway during application of braking force;

a control valve incorporated within said brake torque limiter and interposed in the hydraulic circuit through which hydraulic pressure, from said pilot operated metering valve, is supplied to said disc brake assembly;

said control valve being normally in an open position, when said brake rod assembly is at a fully extended operative position, for circulating hydraulic pressure from said metering valve through said control valve to said disc brake assembly;

said control valve being actuated to a closed position, when said brake rod assembly is contracted from said fully extended operative position by a predetermined excessive braking torque of said aircraft wheel, for blocking hydraulic flow between said disc brake assembly and said pilot operated metering valve, and for trapping metered hydraulic pressure between said brake torque limiter and said disc brake assembly; and

a second chamber formed between said step sections of the dual-diameter piston and matching internal dual-diameter cylinder, for creating an expanding annulus volume in response to contraction of the overall length of said brake rod assembly, to receive hydraulic fluid trapped between said brake torque limiter and said disc brake assembly, and thereby decrease the pressure of said trapped hydraulic fluid resulting in a decrease in the ratio of brake torque reaction relative to metered hydraulic pressure.

6. An individual aircraft wheel torque responsive brake control apparatus for controlling a hydraulically actuated aircraft wheel disc brake assembly having a housing substantially coaxial with a wheel axle of a landing gear strut and rotatable relative thereto, said apparatus comprising:

a metering valve being pilot operated for controlling flow of hydraulic pressure to said disc brake assembly;

a torque arm fixedly attached to said disc brake assembly housing and being angularly movable therewith about said wheel axle, in response to braking reaction torque, associated with frictional adhesion between an aircraft wheel and runway surface, when a braking force is applied to resist rotation of said aircraft wheel;

a brake rod assembly connected at one end to said torque arm and connected at an opposite end to the landing gear strut, for resisting angular displacement of said torque arm and for transmitting braking torque reaction force from said disc brake assembly housing to said landing gear strut;

a brake torque limiter incorporated within said brake rod assembly and being interposed in a hydraulic circuit between said pilot operated metering valve and said disc brake assembly, for controlling the supply and release of hydraulic pressure to and from said disc brake assembly;

said brake torque limiter comprising a cylinder head section with a dual-diameter internally stepped cylinder section, and a matching dual-diameter stepped piston slidably mounted therein;

said brake rod assembly comprising a first brake rod segment fixedly attached to said dual-diameter stepped piston, and a second brake rod segment fixedly attached to said dual-diameter stepped cylinder and head section of said brake torque limiter;

a first chamber formed between said cylinder head section and said dual-diameter stepped piston;

said brake torque limiter being constructed and arranged with respect to said brake rod assembly, so as to normally bias said brake rod assembly in one direction to contract in overall length by directing hydraulic pressure from said pilot operated metering valve into said first chamber, and in the opposite direction to extend said brake rod assembly by reaction torque generated by frictional adhesion between the aircraft wheel and runway during application of braking force;

a control valve incorporated within said brake torque limiter and interposed in the hydraulic circuit through which hydraulic pressure, from said pilot operated metering valve, is supplied to said disc brake assembly;

said control valve being normally in an open position, when said brake rod assembly is at a fully contracted operative position, for circulating hydraulic pressure from said metering valve through said control valve to said disc brake assembly;

said control valve being actuated to a closed position, when said brake rod assembly is extended from said fully contracted operative position by a predetermined excessive braking torque of said aircraft wheel, for blocking hydraulic flow between said disc brake assembly and said pilot operated metering valve, and for trapping metered hydraulic pressure between said brake torque limiter and said disc brake assembly; and

a second chamber formed between said step sections of the dual-diameter piston and matching internal dual-diameter cylinder, for creating an expanding annulus volume in response to extension of the overall length of said brake rod assembly, to receive hydraulic fluid trapped between said brake torque limiter and said disc brake assembly, and thereby decrease the pressure of said trapped hydraulic fluid resulting in a decrease in the ratio of brake torque reaction relative to metered hydraulic pressure.