SEDONI ENRICO (IT)
CANUTO FRANCESCO (IT)
FREDIANI SALVATORE (IT)
SEDONI ENRICO (IT)
CANUTO FRANCESCO (IT)
| WO2007131758A1 | 2007-11-22 |
| US2366310A | 1945-01-02 | |||
| DE10029819C1 | 2002-05-23 | |||
| DE9206185U1 | 1993-09-09 | |||
| US20050209762A1 | 2005-09-22 |
CLAIMS
1) An electronically controlled brake system (10) for trailer tractors; the system (10) comprising: - means (11, 12, 13a, 13b, 15, Cl, C2) for producing and distributing compressed fluid;
- means (14) for braking the tractor and trailer, and for steer-by-braking (SBF) the tractor only;
- compressed-fluid modulating means (18, 19, 24, 25) for activating tractor brakes (21, 23, 27, 29); said modulating means (18, 19, 24, 25) being connected electrically to a brake-control electronic central control unit (CNT) ; further means (16, 30, BTG) for braking the trailer only; and the system (10) being characterized in that said further means (16, 30, BTG) comprise normally-ON valve means (30) normally allowing simultaneous braking of the tractor and trailer; said valve means (30) being controlled by said electronic central control unit (CNT) to switch to OFF when the steer-by-braking function (SBF) is activated.
2) A system (10) as claimed in Claim 1, characterized in that said modulating means (18, 19, 24, 25) act on pneumatic/hydraulic converting means (20, 22, 26, 28) which convert the incoming energy, in the form of compressed air, to hydraulic energy to power corresponding brakes (21, 23, 27, 29) . 3) A system (10) as claimed in either of the foregoing Claims, characterized in that said electronic central control unit (CNT) controls said modulating means (18, 19, 24, 25) . 4) A system (10) as claimed in any one of the foregoing Claims, characterized in that said electronic central control unit (CNT) acquires and process signals indicating the instantaneous speeds of the tractor wheels . 5) A system (10) as claimed in Claim 4, characterized in that said signals indicating the instantaneous speeds of the tractor wheels are supplied by a number of sensors (SSl, SS2, SS3, SS4), each located at a respective wheel. 6) A system (10) as claimed in any one of the foregoing Claims, characterized in that said means (14) for braking the tractor and trailer, and for steer-by-braking (SBF) the tractor only; and - said compressed-fluid modulating means (18, 19, 24, 25) acting on said converting means (20, 22, 26, 28) and for activating tractor brakes (21, 23, 27, 29); form part of an ABS brake system.
7) A system (10) as claimed in any one of Claims 1 to 5, characterized in that said means (14) for braking the tractor and trailer, and for steer-by-braking (SBF) the tractor only; and - said compressed-fluid modulating means (18, 19, 24, 25) acting on said converting means (20, 22, 26, 28) and for activating tractor brakes (21, 23, 27, 29); form part of a brake-by-wire system. 8) A system (10) as claimed in any one of Claims 1 to 6, characterized by comprising four ABS modulators.
9) A system (10) as claimed in any one of Claims 1 to 6, characterized by comprising three ABS modulators, i.e. two ABS modulators for the rear wheels, and one ABS modulator for both the front wheels.
10) A system (10) as claimed in any one of Claims 1 to 6, characterized by comprising two ABS modulators for the rear wheels. |
ELECTRONICALLY CONTROLLED BRAKE SYSTEM FOR TRAILER TRACTORS
The present invention relates to an electronically controlled brake system for trailer tractors.
A major problem of trailer tractors with a steer- by-braking function (SBF) is preventing the trailer from braking, and therefore swerving of the tractor/trailer as a whole, when the (SBF) function is activated (i.e. by the driver to steer the tractor to the right or left) .
The present invention relates to an electronically controlled brake system designed to solve the above problem.
A non-limiting embodiment of the present invention will be described by way of example with reference to the attached drawing.
Number 10 in the attached drawing indicates as a whole an electronically controlled brake system, in particular for tractors, in accordance with the present invention .
System 10 comprises a compressor 11 for supplying compressed air to an air-processing - substantially air- dehumidifying - unit 12.
The processed air is stored in two parallel tanks 13a, 13b, both connected pneumatically to a pedal arrangement 14 which provides for both normal braking
and steer-by-braking (SBF) of the tractor.
As is known, with this type of pedal arrangement
14, when the driver presses the left (or right) pedal only, the brake system only brakes the rear left (or right) wheel, thus reducing the turn radius of the tractor, especially during headland manoeuvres.
A circuit 15 is connected to tank 13a to feed high- pressure (e.g. 8-bar) air to a brake valve 16 of a trailer (not shown) and to a high-pressure coupling 17 forming part of an assembly BTG for pneumatic connection to the trailer brake system (not shown) .
As shown in the attached drawing, a first adjustable low-pressure air circuit Cl and a second adjustable low-pressure air circuit C2 originate from pedal arrangement 14.
First circuit Cl comprises two branches Rl, R2, of which a first branch Rl connects pedal arrangement 14 pneumatically to the trailer brake valve 16, and a second branch R2 connects pedal arrangement 14 pneumatically to two front ABS modulators 18, 19.
ABS modulator 18 regulates compressed-air supply to a corresponding pneumatic/hydraulic converter 20, which converts the incoming energy, in the form of compressed air, to hydraulic energy to power a corresponding front right brake 21 of a front right wheel (not shown) fitted to an axle AXLl with a conventional differential DFl.
Likewise, ABS modulator 19 regulates compressed-air supply to a corresponding pneumatic/hydraulic converter
22, which converts the incoming energy, in the form of compressed air, to hydraulic energy to power a corresponding front left brake 23 of a front left wheel (not shown) also fitted to axle AXLl. A speed sensor SSl and speed sensor SS2 are provided for determining the speed of the front right wheel and front left wheel respectively.
ABS modulators 18, 19 and front-wheel speed sensors SSl, SS2 are connected electrically to an electronic central control unit CNT for the reasons explained below.
Second circuit C2 comprises two branches RMl and RM2.
Like branch Rl of circuit Cl, a first branch RMl connects pedal arrangement 14 pneumatically to valve 16; and the second branch connects pedal arrangement 14 pneumatically to two rear ABS modulators 24, 25.
ABS modulator 24 regulates compressed-air supply to a corresponding pneumatic/hydraulic converter 26, which converts the incoming energy, in the form of compressed air, to hydraulic energy to power a corresponding rear right brake 27 of a rear right wheel (not shown) fitted to an axle AXL2 with a conventional differential DF2.
Likewise, ABS modulator 25 regulates compressed-air supply to a corresponding pneumatic/hydraulic converter
28, which converts the incoming energy, in the form of compressed air, to hydraulic energy to power a corresponding rear left brake 29 of a rear left wheel
(not shown) also fitted to axle AXL2.
A speed sensor SS3 and speed sensor SS4 are provided for determining the speed of the rear right wheel and rear left wheel respectively. ABS modulators 24, 25 and rear-wheel speed sensors SS3, SS4 are also connected electrically to electronic central control unit CNT.
Between valve 16 and trailer brake assembly BTG
(more specifically, between valve 16 and an adjustable coupling 31 forming part of assembly BTG) is interposed an electric valve 30, through which flows the adjustable low-pressure compressed air flowing along first branch
RMl of circuit C2 to assembly BTG.
Electric valve 30 is a normally-open type controlled by electronic central control unit CNT.
System 10 according to the present invention operates as follows:
(A) To simply brake the tractor and trailer (if any) , the driver acts accordingly on pedal arrangement 14; compressed air, adjustable according to driver operation of pedal arrangement 14, is supplied simultaneously to the four ABS modulators 18, 19, 24, 25, thus initiating braking of all four wheels, which is regulated electronically by electronic central control unit CNT using ABS logic.
(B) To simply brake the tractor towing a trailer, electric valve 30 is open, and so permits adjustable-air flow from valve 16 to assembly BTG.
(C) Conversely, to implement the steer-by-braking function (SBF) using pedal arrangement 14, since nothing is gained - in fact, driver safety is even jeopardized - by also involving the trailer, electronic central control unit CNT closes electric valve 30 to cut off adjustable-air supply to assembly BTG.
(D) The four wheel speeds detected by sensors SSl, SS2, SS3, SS4 and transmitted to electronic central control unit CNT obviously also play their part in controlling both normal braking of the four wheels (with electric valve 30 open) , and steer-by-braking (SBF)
(with electric valve 30 closed) of either the rear right wheel by brake 27, or the rear left wheel by brake 29, depending on the desired turn direction. Though the above description with reference to the attached drawing refers to a particular electronic system employing ABS logic, the teachings of the present invention also apply to any electronically controlled brake system, such as the brake-by-wire system. Similarly, though the above description refers to a system comprising four ABS modulators, the teachings of the present invention may also be applied to three- channel systems (i.e. with two ABS modulators for the rear wheels, and one ABS modulator for both the front wheels), or even to two-channel systems (i.e. with only two ABS modulators for the rear wheels) .
The system according to the present invention provides for the following functions:
(1) ABS electronic braking;
(2) Electronic steer-by-braking (e-SBF) ;
(3) Yaw moment control (YMC) ;
(4) Cornering brake control (CBC) for stabilizing and preventing the tractor from swerving when braking around bends; this control operates with no intervention on the part of the ABS system;
(5) Dynamic drift control (DDC) for stabilizing the vehicle when braking around bends, and preventing swerving during intervention of the ABS system; and
(6) Electronic brake distribution (EBD) to avoid damaging the clutch.