Vehicle combination and method for controlling a drive

Abstract

The invention relates to a vehicle combination having a towing vehicle and a trailer, wherein the trailer has a drive which is coupled to a wheel of the trailer, wherein a control unit is provided and is designed to receive a signal of a sensor, wherein the control unit controls the operation of the drive as a function of the signal. Furthermore, the present invention relates to a method for controlling a drive in a vehicle combination.

Claims

1. A vehicle combination, comprising: a towing vehicle; a trailer including a drive coupled to a wheel of the trailer; and a control unit configured to receive a signal of a sensor; wherein the control unit controls an operation of the drive as a function of the signal, wherein a first sensor senses an angular orientation between the towing vehicle and the trailer and transmits it as a first signal to the control unit, wherein the control unit determines an actual angle from the first signal and compares the actual angle with a limiting angle between the towing vehicle and the trailer, wherein the control unit activates the drive only if the actual angle is smaller than the limiting angle, and wherein the limiting angle is between 10° and 45°; wherein the control unit is configured to control a valve arrangement which is configured to control an inflow of hydraulic fluid to the drive, and wherein the drive includes a hydrostatic motor; and wherein the control unit is configured to determine an actual speed of the towing vehicle and/or the trailer and compare the actual speed to a limiting speed, wherein the control unit activates the drive only if the actual speed is lower than the limiting speed where the limiting speed is less than or equal to 15 km/h.

2. The vehicle combination as claimed in claim 1, wherein the actual angle is the angular deviation of the longitudinal axes of the towing vehicle and of the trailer from 180° in the horizontal.

3. The vehicle combination as claimed in claim 1, wherein the limiting angle is between 15° and 35°.

4. The vehicle combination as claimed in claim 1, wherein a second sensor measures the rotational speed of a wheel of the towing vehicle and transmits the rotation speed of the wheel of the towing vehicle as a second signal to the control unit, and wherein the control unit determines the actual speed from the second signal.

5. The vehicle combination as claimed in claim 4, wherein a third sensor measures the rotational speed of the wheel of the trailer to which the drive is coupled and transmits the rotational speed of the wheel of the trailer as a third signal to the control unit, and wherein the control unit determines the actual speed from the third signal.

6. The vehicle combination as claim 5, wherein the limiting speed is between 5 km/h and 15 km/h.

7. The vehicle combination as claimed in claim 6, wherein the limiting speed is between 8 km/h and 15 km/h.

8. The vehicle combination as claimed in claim 5, wherein the control unit determines a speed difference between the wheel of the towing vehicle and the wheel of the trailer from the second signal and the third signal, and compares the speed difference with a limiting difference, wherein the control unit automatically activates the drive if the speed difference is greater than the limiting difference.

9. The vehicle combination as claimed in claim 4, wherein the control unit determines the limiting angle as a function of the actual speed, wherein the limiting angle decreases as the actual speed increases.

10. The vehicle combination as claimed in claim 4, wherein at least one of the second sensor and the third sensor is an inductive sensor.

11. The vehicle combination as claimed in claim 4, wherein the second sensor and/or the third sensor generates a digital square-wave signal.

12. The vehicle combination as claimed in claim 4, wherein at rotational speeds of the wheel of the towing vehicle or the wheel of the trailer which are lower than 10 min.sup.−1 the second sensor and/or the third sensor output a signal which can be interpreted by the control unit.

13. The vehicle combination as claimed in claim 12, wherein at rotational speeds of the wheel of the towing vehicle or the wheel of the trailer which are lower than 1 min.sup.−1 the second sensor and/or the third sensor output a signal which can be interpreted by the control unit.

14. The vehicle combination as claimed in claim 13, wherein at rotational speeds of the wheel of the towing vehicle or the wheel of the trailer which are lower than 0.5 min.sup.−1 the second sensor and/or the third sensor output a signal which can be interpreted by the control unit.

15. The vehicle combination as claimed in claim 1, wherein two drives are provided on the trailer and are respectively coupled to a wheel of the trailer, wherein the control unit actuates the drives equally or differently as a function of the signals which are transmitted via sensors.

16. A method for controlling a drive arranged on a trailer and coupled to a wheel of the trailer, comprising: providing a control unit and a sensor, wherein the control unit is connected to the sensor and the drive via signal lines and/or mechanically; measuring an angle between a towing vehicle and the trailer and/or a rotational speed of a wheel on the towing vehicle and/or a rotational speed of a wheel on the trailer, wherein at least one first sensor senses the angular orientation between the towing vehicle and the trailer; transmitting the measured value or values in the form of a signal to the control unit, including at least of the signal of the first sensor to the control unit; determining actual values via the control unit and comparing the actual values with limiting values, wherein the limiting values are stored in a memory of the control unit or are calculated by the control unit, wherein at least one actual value is an actual angle which is the angular deviation of the longitudinal axis of the towing vehicle and of the trailer from 180° in the horizontal, and wherein at least one limiting value is a limiting angle; and actuating the drive as a function of a switching logic which is stored in the control unit, wherein the control unit activates the drive only if the actual angle is smaller than the limiting angle; wherein the control unit controls a valve arrangement which controls an inflow of hydraulic fluid to the drive, and wherein the drive includes a hydrostatic motor; wherein another actual value of the actual values is an actual speed of the trailer and/or an actual speed of the towing vehicle and wherein another limiting value of the limiting values is a limiting speed, and wherein the control unit actives the drive only if the actual speed of the trailer and/or the actual speed of the towing vehicle is less than or equal to 15 km/h.

17. The method as claimed in claim 16, wherein the control unit receives and processes a user signal, wherein the control unit activates the drive only if both the user signal and the switching logic permit activation of the drive.

18. A vehicle combination, comprising: a towing vehicle; a trailer including a drive coupled to a wheel of the trailer; and a control unit configured to receive a signal of a sensor; wherein the control unit controls an operation of the drive as a function of the signal, wherein a first sensor senses an angular orientation between the towing vehicle and the trailer and transmits it as a first signal to the control unit, wherein the control unit determines an actual angle from the first signal and compares the actual angle with a limiting angle between the towing vehicle and the trailer, wherein the control unit activates the drive only if the actual angle is smaller than the limiting angle, and wherein the limiting angle is between 10° and 45°; wherein the control unit is configured to determine an actual speed of the trailer and/or the towing vehicle and compare the actual speed to a limiting speed, wherein the control unit activates the drive only if the actual speed is less than or equal to 15 km/h.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and features of the present invention can be found in the following description with reference to the appended drawing.

(2) In this context, FIG. 1 shows a schematic view of a vehicle combination and simplified block diagram from which both the individual components of a vehicle combination and a procedure for controlling a drive on such a vehicle combination are apparent. The vehicle combination is constructed according to the invention from a towing vehicle Z and a trailer A. In this context, in this preferred embodiment, the control unit 2 is preferably arranged on the trailer A and secured thereto. The control unit 2 is connected via various signal lines to at least three sensors T which each send signals S to the control unit. Furthermore, the control unit is connected via signal lines to a valve arrangement and can open or close valves via corresponding control signals in the valve arrangement, and can therefore commence or end operation of the drive 4. A first sensor T.sub.1 is preferably arranged here in the region of the king pin and of the fifth-wheel coupling of the vehicle combination and measures the angle of the longitudinal axes of the towing vehicle Z and of the trailer A. The first signal S.sub.1 which is transmitted by this first sensor T.sub.1 is received by the control unit and correspondingly evaluated, wherein the control unit 2 calculates an actual angle α from this first signal S.sub.1. Furthermore, preferably a second sensor T.sub.2 is arranged on the towing vehicle Z, which sensor T.sub.2 measures the rotational speed of a wheel, particularly preferably of a driven wheel of the towing vehicle Z, and sends a corresponding second signal S.sub.2 to the control unit 2. As an alternative to or in addition to the second sensor T.sub.2 a third sensor T.sub.3 is provided on the trailer A, which third sensor T.sub.3 determines the rotational speed of a wheel on the trailer A in a way analogous to the second sensor T.sub.2. The third sensor T.sub.3 sends a corresponding third signal S.sub.3 to the control unit 2. The control unit determines an actual speed v from the second signal S.sub.2 and/or the third signal S.sub.3. The actual angle α is compared here with a limiting angle β by the control unit 2. The actual speed v is compared with a limiting speed u by the control unit 2. In accordance with the output of these comparisons, the control unit 2 sends a corresponding control signal to the drive 4 or indirectly to the drive 4 by means of the actuation of the valve arrangement. If rotational speeds of the respectively driven wheels can be determined both at the trailer A and at the towing vehicle Z, the control unit 2 can determine a speed difference dv from the corresponding second signal S.sub.2 and the third signal S.sub.3 and compare said speed difference dv with a limiting difference du. If a higher rotational speed of the driven wheel is present at the towing vehicle Z than at the driven wheel of the trailer A, the control unit 2 automatically activates the drive 4. In this way, when there is a loss of traction at the towing vehicle Z, the drive 4 can make available an additional torque to propel the vehicle combination and therefore permit the vehicle combination to move forward even in difficult terrain.

LIST OF REFERENCE SYMBOLS

(3) 2—Control unit 4—Drive α—Actual angle β—Limiting angle A—Trailer dv—Speed difference du—Limiting difference S—Signal S.sub.1,2 . . . —First, second, . . . signal T—Sensor T.sub.1,2 . . . —First, second, . . . sensor u—Limiting speed v—Actual speed Z—Towing vehicle