US 4,477,124 AGranted

Speed-responsive retarder control system providing for overheat prevention

AssigneeKabushiki Kaisha Komatsu Seisakusho

InventorMasahiro Watanabe

Life of this patent

Estimating the term…

Loading patent…

Abstract

In response to the actuation of a speed control lever by the vehicle operator, a potentiometer puts out a speed setting signal indicative of a desired vehicle speed. A control circuit responds to this speed setting signal, as well as signals representative of the actual vehicle speed and of the temperature of the retarder fluid, by putting out a first braking signal, corresponding to the difference between the desired and actual vehicle speeds, and a second braking signal corresponding to the difference between the actual acceleration of the vehicle and a preset acceleration. Under the control of the control circuit a selector normally passes the first braking signal and, when either the temperature of the retarder fluid or its temperture rise gradient exceeds a preset maximum, the second braking signal. The first or second braking signal is proportionately translated into a hydraulic pressure for actuation of a retarder. The second braking signal is intended to prevent the overheating of the retarder as when the vehicle is traveling down a long or steep slope.

Claims9

Dependent claims

In a motor vehicle equipped with a fluid-actuated retarder, a control system comprising:

(a) speed control means for actuation by a vehicle operator;
(b) a speed setter responsive to the actuation of the speed control means for putting out a speed setting signal representative of a desired speed of the vehicle;
(c) a speed sensor for putting out an actual speed signal representative of the actual traveling speed of the vehicle;
(d) a temperature sensor for putting out a temperature signal representative of the temperature of a retarder fluid;
(e) a control circuit connected to input the speed setting signal from the speed setter, the actual speed signal from the speed sensor, and the temperature signal from the temperature sensor, the control circuit putting out a first braking signal, corresponding to the difference between the speed setting signal and the actual speed signal, and a second braking signal of smaller magnitude than the first braking signal;
(f) selector means under the control of the control circuit for normally permitting the passage therethrough of the first braking signal from the control circuit and, in the event of a prescribed change in the temperature of the retarder fluid as represented by the temperature signal, the second braking signal from the control circuit;
and
(g) a braking force generator responsive to the first or second braking signal from the selector means for proportionately generating a braking force for actuation of the retarder.

5 more elements

In a motor vehicle such as a dump truck equipped with a fluid-actuated retarder, a control system comprising:

(a) speed control means for manual actuation by a vehicle operator;
(b) a speed setter responsive to the actuation of the speed control means for putting out an electric speed setting signal representative of a desired speed setting for the vehicle;
(c) a speed sensor for putting out an electric actual speed signal representative of the actual traveling speed of the vehicle;
(d) a temperature sensor for putting out an electric temperature signal representative of the temperature of a retarder fluid;
(e) a control circuit connected to input the speed setting signal from the speed setter, the actual speed signal from the speed sensor, and the temperature signal from the temperature sensor, the control circuit putting out an electric first braking signal, corresponding to the difference between the speed setting signal and the actual speed signal, and an electric second braking signal of smaller magnitude than the first braking signal;
(f) means for converting the first and second braking signals from electric to fluid form;
(g) selector means under the control of the control circuit for normally permitting the passage therethrough of the first braking signal from the control circuit and, when the temperature or the temperature rise gradient of the retarder fluid exceeds a preset maximum, of the second braking signal from the control circuit, the first and second braking signals selectively passing the selector means either before or after conversion from electric to fluid form;
and
(h) a braking force generator responsive to the first or second braking signal for generating a corresponding braking force for actuation of the retarder.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/332,735Filed 21 Dec 1981
Priority: JP 55-18505327 Dec 1980
Granted: 16 Oct 1984
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

B60K 31/102
And means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which…:…
B60T 7/12
Brake-action initiating means: for automatic initiation; for initiation not subject to will of driver or passenger
B60T 10/02
Control or regulation for continuous braking making use of fluid or powdered medium, e.g. for use when descending a long slope: with hydrodynamic…
B60T 13/585
Combined or convertible systems: comprising friction brakes and retarders