Control valve, electronically controllable braking system, and method for controlling the electronically controllable braking system

Patent metadata

Field	Value
Publication number	US-2021237702-A1
Application number	US-201917050687-A
Country	US
Kind code	A1
Filing date	Mar 29, 2019
Priority date	Apr 26, 2018
Publication date	Aug 5, 2021
Grant date	—

Abstract

A control valve (12) for applying a spring-loaded brake pressure (p3b) to spring-loaded parts of a rear-axle wheel brake is provided. The control valve (12) is activatable pneumatically via a second control input (12b) with a parking-brake control pressure (p5). The parking-brake control pressure (p5) can act in such a manner on a control mechanism (14b, 15b, 17c, 22, 23, 24) arranged in a valve housing (12f) of the control valve (12) that a spring-loaded brake pressure (p3b) arises at a control output (12c) of the control valve (12) as a function of the parking-brake control pressure (p5) for bringing about a parking-brake braking specification with the spring-loaded parts of the rear-axle wheel brakes. The control valve (12) has a first control connection (12a) connectable to an adjustable first control chamber (14a), which is operatively connected to the control mechanism (14b, 15b, 17c, 22, 23, 24).

First claim

1 . A control valve ( 12 ) for applying a spring-loaded brake pressure (p 3 b ) to spring-loaded parts ( 3 b ) of a rear-axle wheel brake ( 3 ), wherein the control valve ( 12 ) is activatable pneumatically via a second control input ( 12 b ) with a parking-brake control pressure (p 5 ), wherein the parking-brake control pressure (p 5 ) can act in such a manner on a control mechanism ( 14 b , 15 b , 17 c , 22 , 23 , 24 ) arranged in a valve housing ( 12 f ) of the control valve ( 12 ) that a spring-loaded brake pressure (p 3 b ) arises at a control output ( 12 c ) of the control valve ( 12 ) as a function of the parking-brake control pressure (p 5 ) for bringing about a parking-brake braking specification (VP) with the spring-loaded parts ( 3 b ) of the rear-axle wheel brakes ( 3 )
wherein the control valve ( 12 ) includes a first control connection ( 12 a ) for activating the control valve ( 12 ) with a service-brake control pressure (pV; pR) which is dependent on a service-brake braking specification (VB), wherein the first control connection ( 12 a ) is connectable to an adjustable first control chamber ( 14 a ), wherein the first control chamber ( 14 a ) is operatively connected to the control mechanism ( 14 b , 15 b , 17 c , 22 , 23 , 24 ) arranged in the control valve ( 12 ) such that, during an adjustment of the first control chamber ( 14 a ) as a result of pressurization with the service-brake control pressure (pV; pR), the spring-loaded brake pressure (p 3 b ) at the control output ( 12 c ) is set as a function of the service-brake control pressure (pV; pR), the parking-brake control pressure (p 5 ), or a combination of the brake control pressure (pV; pR) and the parking-brake control pressure (p 5 ).

2 . The control valve ( 12 ) as claimed in claim 1 , wherein the control mechanism comprises an adjustable second control chamber ( 14 b ) and an adjustable second control piston ( 15 b ), wherein the parking-brake control pressure (p 5 ) is admitted into the second control chamber ( 14 b ) via the second control input ( 12 b ) and the second control piston ( 15 b ) is adjustable in a first direction (R 1 ) or a second direction (R 2 ) opposed to the first direction (R 1 ) by action of the parking-brake control pressure (p 5 ) on the second control piston ( 15 b ).

3 . The control valve ( 12 ) as claimed in claim 2 , wherein the second control chamber ( 14 b ) is bounded by a third wall ( 17 c ) arranged on the adjustable second control piston ( 15 b ), wherein the third wall ( 17 c ) is movable in relation to the valve housing ( 12 f ) such that the second control piston ( 15 b ) is adjusted by action of the parking-brake control pressure (p 5 ) on the third wall ( 17 c ).

4 . The control valve ( 12 ) as claimed in claim 2 , wherein the first control chamber ( 14 a ) is operatively connected to a first control piston ( 15 a ), wherein the first control piston ( 15 a ) is operatively connected to the second control piston ( 15 b ) such that the second control piston ( 15 b ) is carried along by an adjustment of the first control piston ( 15 a ).

5 . The control valve ( 12 ) as claimed in claim 4 , wherein the first control piston ( 15 a ) and the second control piston ( 15 b ) are fixedly connected to one another.

6 . The control valve ( 12 ) as claimed in claim 4 , wherein the first control chamber ( 14 a ) is bounded by a first wall ( 17 a ) which is movable in relation to a valve housing ( 12 f ) and by a second wall ( 17 b ) which is fixed to the valve housing ( 12 f ), wherein the first control piston ( 15 a ) is connected to the first wall ( 17 a ) such that the first control piston ( 15 a ) and the second control piston ( 15 b ) which is operatively connected thereto are forced by an increase in pressure in the first control chamber ( 14 a ) in a first direction (R 1 ).

7 . The control valve ( 12 ) as claimed in claim 6 , wherein the second control chamber ( 14 b ) is arranged relative to the first control chamber ( 14 a ) such that the second control piston ( 15 b ) and the first control piston ( 15 a ) which is operatively connected thereto are forced in the second direction (R 2 ) when there is an increase in pressure in the second control chamber ( 14 b ).

8 . The control valve ( 12 ) as claimed in claim 7 , wherein the second control chamber ( 14 b ) is bounded by the second wall ( 12 b ) which is fixed to the valve housing ( 12 f ), and wherein, when there is an increase in pressure in the second control chamber ( 14 b ), the second control piston ( 15 b ) is pushed away from the second wall ( 12 b ) in the second direction (R 2 ), and, when there is an increase in pressure in the first control chamber ( 14 a ), the first control piston ( 15 a ) is pushed away from the second wall ( 12 b ) in the first direction (R 1 ).

9 . The control valve ( 12 ) as claimed in claim 2 , wherein the first control chamber ( 14 a ) and the second control chamber ( 14 b ) interact with each other via the control pistons ( 15 a , 15 b ) such that a spring-loaded brake pressure (p 3 b ) arises at the control output ( 12 c ), said spring-loaded brake pressure being dependent on the parking-brake control pressure (p 5 ) prevailing in the second control chamber ( 14 b ) or on the service-brake control pressure (pV; pR) prevailing in the first control chamber ( 14 a ), depending on which of the two control pressures (p 5 , pV; pR) is the highest.

10 . The control valve ( 12 ) as claimed in claim 3 , wherein an area ratio (F) between the first wall ( 17 a ) and the third wall ( 17 c ) is between 1:2 and 2:1.

11 . The control valve ( 12 ) as claimed in claim 2 , wherein an axially movable valve body ( 22 ) which is pretensioned by a compression spring ( 23 ) defines the control mechanism, wherein, depending on the axial adjustment of the valve body ( 22 ), the control output ( 12 c ) is connectable either via a pressure chamber ( 16 ) to a venting connection ( 12 e ) for reducing the spring-loaded brake pressure (p 3 b ) or to a supply connection ( 12 d ) for increasing the spring-loaded brake pressure (p 3 b ), wherein the second control piston ( 15 b ) adjusts the valve body ( 22 ) axially as a function of the parking-brake control pressure (p 5 ), the service-brake control pressure (pV; pR), or a combination of the brake control pressure (pV; pR) and the parking-brake control pressure (p 5 ).

12 . The control valve ( 12 ) as claimed in claim 1 , wherein the control valve ( 12 ) includes a control device ( 20 ), wherein the control device ( 20 ) switches over a third control piston ( 15 c ) such that the first control connection ( 12 a ) is connected to the adjustable first control chamber ( 14 a ) via a connecting channel ( 19 ) for guiding the service-brake control pressure (pV; pR) into the first control chamber ( 14 a ), or that the atmosphere (A) is connected to the first control chamber ( 14 a ) for venting the first control chamber ( 14 a ).

13 . An electronically controllable brake system ( 1 ) comprising:
front-axle wheel brakes ( 2 ), rear-axle wheel brakes ( 3 ) with a spring-loaded part ( 3 b ) and a membrane part ( 3 c ), an electro-pneumatically controllable front-axle pressure modulator ( 6 ) for outputting a front-axle brake pressure (p 2 ) to the front-axle wheel brakes ( 2 ), an electronically controllable rear-axle pressure modulator ( 11 ) for outputting a membrane-brake pressure (p 3 c ) to the membrane parts ( 3 c ) of the rear-axle wheel brakes ( 3 ), a centr

Assignees

• Wabco Europe Bvba

Inventors

• Beier Peter
• Otremba Robert
• Van Thiel Julian

Classifications

• B60T2270/413

  Plausibility monitoring, cross check, redundancy · CPC title

• B60T2270/403

  Brake circuit failure · CPC title

• B60T2270/402

  Back-up · CPC title

• B60T17/221

  Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems (hydraulic pressure systems in general F15B19/00, F15B21/04; testing structures or apparatus G01M) · CPC title

• B60T15/22

  with one or more auxiliary valves, for braking, releasing, filling reservoirs · CPC title