Apparatus for the automatic engagement and disengagement of drive elements of a motor vehicle

Claim 1

Apparatus for the automatic engagement and disengagement of drive components of a motor vehicle with a driven axle, particularly of the drive of at least one further axle and/or of locks for auxiliary gears 10 and/or differential gears, with sensors for the rotary speeds of the wheels and/or of the gear input shafts and for the steering angle of the vehicle and with an electronic unit which generates a switching signal when a value associated with the rotary speeds of the wheels exceeds a limit value associated with the steering angle, wherein the electronic unit engages the additional drive and/or the locks individually or 5 simultaneously or in a predetermined chronologically staggered sequence, if a) the travelling speed has not exceeded a first limit speed value or has fallen below a second lower limit speed value and/or b) the acceleration of the wheels of a driven axle or of the vehicle is above a limit acceleration value, and/or c) the instantaneous tractive slip value or thrust slip value is above a limit slip value associated with the 20 travelling speed, and/or d) a quantity characteristic of the movement behaviour of the vehicle is above a value or outside a value range which is associated with the steering angle and/or with the travelling speed, and said additional drive and/or said locks being disengaged if e) the travelling speed has exceeded the first limit speed value and has not fallen below the second limit 25 speed value and/or f) the acceleration of the wheels of the driven axle or of the vehicle is below the limit acceleration value, and/or g) the instantaneous tractive slip value or thrust slip value is below the limit slip value associated with the travelling speed or one associated with the travelling speed and with the difference or rotary speeds of the 30 steered wheels, and/or h) the quantity characteristic of the movement behaviour of the vehicle is below the value or within the value range which is associated with the steering angle and/or with the travelling speed, or i) the service brake is actuated at a travelling speed above the limit travelling speed value, and that an adaptively operating matching electronic system is provided which adjusts the electronic unit in respect of 35 different wheel diameters and of the steering angle applicable to straight-line travel.

Claim 7

An apparatus according to anyone of Claims 1 to 5, wherein the instantaneous slip value consists of the sum of the correct-sign difference between the mean rotary speed of the wheels of the driven axle and the mean rotary speed of the wheels, or the rotary speed of the slower wheel, of an undriven axle and of a correction value.

Claim 8

An apparatus according to anyone of Claims 1 to 6, wherein the quantity characteristic of the movement behaviour of the vehicle is approximately a parameter of the rotary speeds of the wheels of an axle or of the mean rotary speeds of the wheels of two axles.

Claim 9

An apparatus according to anyone of Claims 1 to 6, wherein the quantity characteristic of the movement behaviour of the vehicle approximates to the curve radius travelled andlor the road curvature. 55

Claim 10

An apparatus according to anyone of Claims 1 to 6, wherein the quantity characteristic of the movement behaviour of the vehicle approximates to the yawing angular velocity of the vehicle associated with the travelling speed.

Claim 11

An apparatus according to anyone of Claims 1 to 6, wherein the quantity characteristic of the movement behaviour of the vehicle approximates to the transverse acceleration of the vehicle associated 60 with the travelling speed.

Claim 12

An apparatus according to anyone of the preceding Claims, wherein at least one of the instantaneous measured values is passed through a first time filter with a given time constant.

Claim 14

An apparatus according to anyone of Claims 11 or 12, wherein at least one of the switching stages is engaged when an instantaneous measured value passed through the associated first time filter exceeds the associated limit value or departs from the associated-value range.

Claim 22

An apparatus acording to anyone of Claims 18to 20, wherein the balancing with a given adjusting speed occurs only when a) the travelling speed is within a given value range, b) the vehicle acceleration is below a given limit value, c) the steering angle varies only within a determined angular range and d) all the engageable drives and locks are disengaged and the brake is not actuated.

Claim 25

An apparatus according to anyone of the previous Claims, wherein an indicator device is provided 35 whereby the switching state of the individual switching stages can be indicated.

Claim 26

An apparatus for controlling the automatic engagement or disengagement of the drive components of a motor vehicle, substantially as hereinbefore described and with reference to the accompanying drawings. Printed in the UK for HMSO, D8818935, 8186, 7102. Published by The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.

Claim 27

An apparatus for controlling the automatic engagement or disengagement of the drive components of a motor vehicle, substantially as hereinbefore described and with reference to the accompanying drawings. Printed in the UK for HMSO, D8818935, 8186, 7102. Published by The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.