GB2136066A

GB2136066A - Vehicle change-speed gearbox

Info

Publication number: GB2136066A
Application number: GB08404160A
Authority: GB
Inventors: Hans Hagen
Original assignee: MAN Maschinenfabrik Augsburg Nuernberg AG
Current assignee: MAN AG
Priority date: 1983-02-26
Filing date: 1984-02-17
Publication date: 1984-09-12
Also published as: SE8306872L; GB8404160D0; SE8306872D0; DE3306882A1; IT8447744A0; FR2541792B1; GB2136066B; FR2541792A1; IT1180665B

Abstract

A vehicle change-speed gearbox consists of a single change-speed gearbox unit or of several successively interconnected change-speed gearbox units. An indicating device is provided in which each individual indication (1 to 15, R1, R2) is representative of the respective gear ratio prevailing at the moment. For this purpose, sensors are arranged in each of the gearbox units to communicate the respective shifting position to the indicating device. <IMAGE>

Description

SPECIFICATION Vehicle change-speed gearbox This invention relates to a vehicle changespeed gearbox.

The majority of vehicle change-speed gearboxes having one or more gear selector levers possess an indicating device to indicate the gear selected. Such an indicating device consists, e.g.

for a reduction gear of a cross-country vehicle, of symbols arranged at the extreme points of travel of the respective gear selector lever, and permit a relationship to be established between the symbol and the respective position of the gear selector lever.

Such indicating devices, however, merely serve to familiarise the driver with the gear positions before travel. The indicating device cannot be easily recognized or read during travel because of their attachment and their design.

During travel the vehicle operator will normally reach for the respective gear selector lever to feel the gear he is in.

In many cases, however, especially with commercial vehicles having a large number of gears, this can no longer be done because the various positions of the gear selector lever can no longer be distinguished by "feel." With cross-country vehicles or other vehicles with power trains of several successively interconnected gearboxes between the engine and the live axle, each gearbox being provided with its own gear selector lever, it would in many driving situations take much too long to "feel" the various gear selector levels. The vehicle operator will normally have to remember which gear he is in, or at least what the selected position of the reduction gear is. This diverts the attention of the driver away from the actual driving, and a faulty memory may be the cause of driving errors perhaps even leading to an accident.

An object of the invention is to overcome these disadvantages.

In a broad aspect of the present invention the state-of-the-art indicating device is improved such that the vehicle operator is continuously being advised of the respective gear ratio and, if necessary, of the direction of travel selected at the moment.

The invention provides a vehicle change-speed gearbox comprising a change-speed gearbox unit or a plurailty of successively-interconnected change-speed gearbox units to vary the gear ratio and the direction of travel, having at least one gear selector lever and an indicating device to indicate the respective gear selected, the lever and the device being arranged in an operating station of the vehicle, wherein on the unit or at least one of the units, each shift position is related to a sensor generating a signal when the unit is in the respective shift position, the sensors being connected to the indicating device so as to give individual indications of the respective gear ratio and the respective direction of travel selected, the indications being separately controlled by the respective input signal or signals.

Where the change-speed gearbox consists of a single change-speed gearbox unit only, each individual sensor is related to an individual indication illustrating the respective gear engaged.

Where use is made of several successivelyinterconnected change-speed gearbox units, the output signal from the sensors of each changespeed gearbox unit is processed together with the signals from the other change-speed gearbox units such that after processing, only a single indication is actuated to indicate the prevailing gear ratio and perhaps the direction of travel. It will also be possible -- by adding further information, such as an additional individual indication or a special arrangement of the individual indications -- to tell the vehicle operator which shift configuration of the various change-speed gearbox units led to the presently prevailing gear ratio.In this manner the vehicle operator has at any time an overview of the shift configuration of the entire change-speed gearbox assembly of the vehicle, enabling him to respond to the respective driving situation by selecting the proper gear via the shortest procedure also if that should require the operation of several gearshift levers.

The sensors may be adapted to provide mechanical, pneumatic or hydraulic signals.

In the known arrangement a readily visible individual indicator is provided at the operating station of the vehicle to enable a representative indication to be given of the shifting position of a gearbox, i.e. of the differential mechanism, and the individual indication is necessarily also connected to a sensor; the latter is nevertheless arranged, in the form of a limit contact, in the travel range of the selector for the gearbox concerned, and it accordingly indicates only the respective position of the selector lever. Then when an electrically, pneumatically or hydraulically remotely-controlled gearbox is used, and when more particularly the gear selector lever has fewer gearshift positions than the gearbox involved, the position of the gear selector lever may deviate from the actual configuration of the gearbox it may fail to indicate that configuration clearly.

With mechanically-controlled gearboxes, the shifting position of which necessarily relates to the position of the gear selector lever, it would conceptually be possible to arrange the various sensors within its path of travel, but because of the short actuating distances involved, this would require the use of a high-precision device that would hardly be suitable for the rough operating conditions encountered over the years in a commercial vehicle.

The present invention now permits the sensors to be arranged directly on or in the respective gearbox unit and so protect them from the environment.

Preferably, the sensors take the form of electrical limit contacts and are related to the extremes of travel of the various gearbox shifting rods. In these places the shifting travels are long and the respective limit switch can be made a rugged and reliable construction.

In this case it will also be possible to form a single sensor from several interlocking limit switches, so that in the presence of several switching rods within a gearbox, the respective gear ratios selected can be indicated unmistakably.

Preferably, the individual indications are designed as variously-coloured illuminated indications, where light-emitting diodes provide a particular advantage on account of their low power absorption and long life.

It will be of advantage to link individual illuminated indications with individual gear ratios, whereas the colour of the illuminated indication will show, e.g., whether a reduction gear was engaged or not to achieve the gear ratio indicated.

Also, light-emitting diodes require very little space for installation, which enables them to be especially advantageously arranged as a combined indicating device on the gear selector lever or perhaps even on its handle.

It will likewise be possible to combine the indicating device, if formed by small light-emitting diodes, inside an area small enough to fit on the instrument panel without disturbing the other indicating instruments required for operation.

Where several change-speed gearbox units are successively interconnected and one of the units is in its idle position, there will be no signal input to the indicating device, for the reason that no gear ratio is selected.

In order to apprise the vehicle operator nevertheless of the gear the respective, still engaged gearbox unit is in, one or several indicating units may be actuated by the input signals still present.

In this case it will be possible, e.g. to detect this condition by way of suitable electrical circuitry and display it by way of a separate individual indication, which used additionally to the other indications, may be representative of the shifting configuration of the reduction gear.

It will also be advantageous, however, to actuate simultaneously all individual indicating units that can be reached at the prevailing shift configuration when the gearbox presently in the idle position is operated into a shifting position.

An embodiment of the invention will now be described with reference to the accompanying drawing, which illustrates individual indications 1 to 1 5 and R1, R2 at the ends of the respective lanes of a gearshifting gate.

Such individual indications, however, may also be located elsewhere, using the same arrangement, where a symbol is used in lieu of the gearshifting gate.

The shifting lanes I to V (this example is for a 1 6-speed gearbox) are characterized in a second plane by the select position of the gearshift lever.

Gear 1 or gear 2, e.g., are thus attained by pulling the lever upward, or depressing it, in the shifting position 1, 2 at the end of the shifting lane II.

Correlated with these contacts is a shifting unit on the gearbox to perform the shifting movements, when triggered by electrical contacts in the gate, by hydraulic or pneumatic means, so that the individual indications may also be used for indicating the completion of the shifting process.

In this case a reduction gear can be engaged or disengaged by, e.g., depressing or pulling the gearshift lever.

The arrangement as here shown, however, may also represent a gearshifting gate associated with a mechanical gear selector lever the vertical position of which is fixed, when a separate lever is required for engaging the reduction gear.

In this case the individual displays 2, 3, 6, 7, 10,11,14, 15andR1,whichbytheir arrangement are distinguished from the remaining individual indications, indicate that the reduction gear is engaged. When one of said individual indications lights up, the vehicle operator not only knows the respective gear ratio in use, but he also knows the shifting configuration of the reduction gear.

Using the present embodiment, and with the change-speed gearbox in the idle position and the reduction gear engaged, all individual indications mentioned can be made to illuminate simultaneously, while with the reduction gear disengaged, all other individual indications will illuminate simultaneously.

It will also be possible, however, to make the individual indications different colours, with one colour, e.g., indicating that the reduction gear is engaged, while another colour indicates that it is disengaged.

The gearbox illustrated makes it possible to recognize at once and at any time - even in critical driving situations when fast and proper shifting is important -- which gear is engaged and, if necessary, what is the shifting position of the various gearbox units, enabling the vehicle operator to use his experience promptly and correctly to take the measures required for gearshifting.

Claims

1. A vehicle change-speed gearbox comprising a change-speed gearbox unit or a plurality of successively-interconnected change-speed gearbox units to vary the gear ratio and the direction of travel, having at least one gear selector lever and an indicating device to indicate the respective gear selected, the lever and the device being arranged in an operating station of the vehicle, wherein on the unit or at least one of the units, each shift position is related to a sensor generating a signal when the unit is in the respective shift position, the sensors being connected to the indicating device so as to give individual indications of the respective gear ratio and the respective direction of travel selected, the indications being separately controlled by the respective input signal or signals.

2. A gearbox as claimed in claim 1, wherein the sensors are electrical limit contacts arranged at the extreme points of travel of gearbox shifting rods or parts thereof.

3. A gearbox as claimed in claim 1 or 2, wherein the individual indications take the form of illuminated displays.

4. A gearbox as claimed in claim 3, wherein the illuminated displays have different colours.

5. A gearbox as claimed in claim 3 or 4, wherein the illuminated displays are light-emitting diodes.

6. A gearbox as claimed in any of claims 1 to 5, wherein the individual indications are arranged on an instrument base, e.g. the instrument board, and/or on the gear selector lever or levers.

7. A gearbox as claimed in any of claims 1 to 6, wherein when several gearbox units are used and the sensors related to any one gearbox unit fail to provide a signal, one or several individual indications may be actuated directly by the signals from the other gearbox units.

8. A vehicle change-speed gearbox substantially as herein described with reference to the accompanying drawing.

9. A vehicle having a change-speed gearbox as claimed in any one of the preceding claims.