Method and device for tandem- or multiple-axle drive for a vehicle

Patent metadata

Field	Value
Publication number	US-10384537-B2
Application number	US-201415535069-A
Country	US
Kind code	B2
Filing date	Dec 23, 2014
Priority date	Dec 23, 2014
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

A wheel suspension system and a method for controlling the system. The wheel suspension system includes a first axle provided with wheels and a second axle provided with wheels. The first axle is connected to a first driveshaft portion via a first differential 6 a and the second axle is connected to a second driveshaft portion via a second differential 6 b . The system further includes angular speed sensors designed to detect the rotational speed of the axles, and/or the rotational speed of the respective wheels. The angular speed sensors are connected to an electronic control unit (ECU) which is designed to calculate a difference between the angular speed of the first and second axles, and/or a difference between the angular speed of the respective wheels by the use of input data from the angular speed sensors. The speed difference can be used as an indication of different wheel radius of the wheels. The system includes a coupling, e.g. a dog clutch arrangement, arranged in the driveshaft and positioned between the first and second drive shaft portions for changing the first and second drive shaft portions between being drivingly connected and disconnected.

First claim

The invention claimed is:

1. A control method for a wheel system including a multi-drive axle for a vehicle, the wheel system comprises at least two driven axles whereof each axle is provided with a pair of wheels and connected to a driveshaft via differentials, the driveshaft comprising a coupling positioned between each differential so as to divide the driveshaft into different driveshaft portions which can change between being drivingly connected and disconnected to the driveshaft, the wheel system further comprising angular speed sensors designed to detect an angular speed of the wheels connected thereto, the control method comprising:
controlling the coupling to be disconnected such that each drive shaft portion is drivingly disconnected from at least one further drive shaft portion,
detecting the angular speed of the wheels connected thereto by the angular speed sensors while the driven axles are drivingly disconnected;
using the detected angular speed of the wheels connected thereto in order to calculate a difference between the angular speed of the respective wheels of the driven axles;
comparing the angular speed difference detected between wheels with reference values; and
using the comparison of the angular speed difference to be an indication of different wheel radius and triggering at least one of a warning signal and a control action in case the angular speed difference is outside an allowable value.

2. The control method according to claim 1 , wherein the wheel system comprises a lifting mechanism acting on a driven rear axle for being able to shift the position of the wheels on that axle, which constitutes a liftable axle, between being in a working position in contact with a ground surface and being lifted up to be in a resting position above a ground contact level, the method comprising:
lowering the liftable axle from an up-lifted resting position, in which a wheel pair of the liftable axle is above the ground contact level, to a lowered working position, in which the wheels are in contact with the ground, while the coupling is disconnected such that the liftable axle is drivingly disconnected from the other axles;
maintaining the coupling disconnected to keep the driven axles drivingly disconnected at least until it is indicated that the detected angular speed values from the angular speed sensors, indicating the angular speed of the wheel pairs, are stabilized.

3. The control method according to claim 2 , wherein if the angular speed difference is outside a critical upper limit the liftable axle is controlled to be drivingly disconnected from the other axles.

4. The control method according to claim 1 , wherein if a calculated angular speed difference between the angular speed of the driven axles exceeds a “change warning limit”, then it is indicated that a change of position of the tires from one axle to another should be performed.

5. The control method according to claim 1 , wherein if a calculated angular speed difference between the angular speed of the driven axles exceeds a “check warning limit”, then it is indicated that a manual check of the conditions of the tires should be performed.

6. The control method according to claim 1 , wherein the angular speed is detected by wheel speed angular sensors for a wheel on each side of the axles for all axles being connectable to the driveshaft in the wheel system and the angular speed for each one of the wheels is used in order to calculate an angular speed difference between the axles.

7. The control method according to claim 1 , wherein the detected angular speed of the wheels used in order to calculate the angular speed difference between at least one of the angular speed of the first and second axles and the difference between the angular speed of the respective wheels of the first and second axles are taken when at least two of the following conditions are fulfilled:
a turning radius of the vehicle is above a prescribed limit;
speed variations of the vehicle are below a prescribed limit;
a tire pressure difference between different wheels is within a prescribed limit;
a load distribution between the different axles is within a prescribed limit;
the wheels are not being controlled by an anti-block braking system or a wheel slip control system while the angular speed is detected;
a braking force on the measured wheels is below a prescribed value;
a driving torque on the measured wheels is below a prescribed value;
a tire temperature, or tire temperature difference, is within a prescribed limit;
the axle differentials are free;
a measuring time point is selected by predicting an upcoming driving sequence.

8. A computer comprising a computer program for performing the steps of claim 1 when the program is run on the computer.

9. A non-transitory computer readable medium carrying a computer program for performing the steps of claim 1 when the program product is run on a computer.

10. An electronic control unit (ECU) for controlling a wheel system, the electronic control unit (ECU) being configured to perform the steps of the method according to claim 1 .

Assignees

• Volvo Truck Corp

Inventors

• Flogård Anders
• Fagergren Mats
• Larsson Lena
• Öberg Jan

Classifications

• B60W10/22

  including control of suspension systems · CPC title

• B60W10/119

  including control of all-wheel-driveline means, e.g. transfer gears or clutches for dividing torque between front and rear axle (B60W10/14 takes precedence) · CPC title

• B60K17/36

  for driving tandem wheels · CPC title

• B60K23/0808

  for varying torque distribution between driven axles, e.g. by transfer clutch · CPC title

• B60K23/08

  for changing number of driven wheels {, for switching from driving one axle to driving two or more axles (B60K17/3515 takes precedence)} · CPC title