WO1990014534A1

WO1990014534A1 - Electro-pneumatic gear changing system

Info

Publication number: WO1990014534A1
Application number: PCT/EP1990/000766
Authority: WO
Inventors: Karlmann Hamma
Original assignee: Zahnradfabrik Friedrichshafen Ag
Priority date: 1989-05-16
Filing date: 1990-05-12
Publication date: 1990-11-29
Also published as: EP0472552A1

Abstract

An electro-pneumatic changing system for a gearbox (1) in which the gears which are controlled by magnetic valves (41 to 48) are changed pneumatically via servo cylinders (21 to 25), whereby, in normal operation, the magnetic valves (41 to 48) or the central valve block (4) in which the magnetic valves are contained are powered via a compressed air line. During emergency operation, the compressed air is supplied directly via a separate pilot valve (9) to a selection of servo cylinders (21 to 24). There is a second compressed air source (7) linked to a multi-position pilot valve (9) acting as an emergency changing valve. The servo cylinders (21 to 24) for the neutral position and the gears in the emergency change system (R, I, II) may be connected to the second compressed air source (7) via changeover valves (53) and the multi-position pilot valve (9). The compressed air supply may be safeguarded via safety pilot valves (55, 56) mechanically connected to the starting and changing coupling or to the handbrake lever.

Description

Electro-pneumatic switching system

The invention relates to an electro-pneumatic switching system according to the preamble of claim 1.

Such shift systems, which are intended to relieve the driver of a primarily heavy vehicle with often many gears, depending on the design of the system, are known in many variants.

With Easyshift (ES) a switching system is known from the publication F 43546 / RT 3430 887, in which the operating elements (shift lever and clutch pedal) are present as in the conventional transmission and must also be operated by the driver. The usual shift linkage is no longer present, however, because the driver's shift commands are given electrically to the central valve block on the manual transmission via the gear switch or shift lever. There these electrical switching impulses are converted into pneumatic signals, the release switch on the clutch pedal and the main switching valve then give the command for a shift and are carried out by the corresponding shift cylinders.

A switching system with an automatic preselection circuit (AVS) is already known - ZF document F 32437 / RT 3431 887 - in which the starting process and all other circuits are preselected in a specific driving position of the preselection switch. In this position, the driver only has to actuate the clutch pedal to change gear. The gear shift then takes place pneumatically via shift cylinders, as already described in connection with the ES shift system. What is common to such switching systems is that electrical energy for actuating the solenoid valves and compressed air for the actuating cylinders - gear shift cylinders - are required to move the vehicle, primarily for gear shifting.

An emergency circuit is also known which operates purely pneumatically and, if the electrical system fails, enables the vehicle to be moved, albeit to a limited extent.

However, this device can only be switched on when the vehicle is at a standstill and is ineffective if the compressed air fails. But the general compressed air system of the vehicle is particularly susceptible to failure, because in addition to the solenoid valves for the gear shift, other consumers, e.g. B. the operation of the doors in a bus, connected and therefore this compressed air circuit is widely branched and very prone to failure. So z. B. with a longer service life of the vehicle due to defects in seals, the pressure drop so far that the vehicle is no longer switchable. But even during operation, a sealing sleeve can burst, making the vehicle unable to move.

It is therefore an object of the invention to further develop an electro-pneumatic switching system according to the preamble of claim 1 in a simple manner, so that in the event of a compressed air failure in the so-called general supply circuit of the vehicle and in the event of a power failure, the latter can be moved on or put into operation at all.

This object is achieved with the characterizing features of claim 1. With a second pressure medium source and a separately arranged multi-position switching valve connected via a short line, an extremely insensitive pressure medium system is available for the emergency switching of the transmission, which is provided both by the general compressed air supply circuit and, if necessary, by one Hand pump can be filled. During normal operation, in which the actuating cylinders for the gear change are supplied via the solenoid valves from the general compressed air supply circuit, the additional pressure medium system is shut off and is therefore particularly insensitive to a drop in pressure. A hand pump is therefore only required if there is an extreme need for safety. The compressed air supply to the multi-position switching valve for the emergency gearshift can still be made dependent on safety valves which are connected to the clutch and, in special cases, to the handbrake actuation.

The invention is not limited to the combination of features of the claims. For the specialist, there are further useful combinations of ^" claims and individual claim characteristics from the task.

Further details of the invention will be explained with reference to drawings and exemplary embodiments. Show it:

1 shows the ZF switching system AVS - an automated preselection circuit;

Fig. 2 shows the pneumatic emergency switching arrangement in

Connection to the normal compressed air supply to the actuating cylinders via the solenoid valves.

In the switching system AVS of FIG. 1, a transmission 1 is switched electropneu atic. In the M position (manual) of the rotary switch 80, the switching commands arise when the tip switch 800 is actuated and for the clutch actuation in the trigger switch 81 am

Clutch pedal 82 and reach the electronic control unit 10 and the central via electrical lines 83 Valve block 4, in which the solenoid valves 41 and 41A to 48 are arranged together. In position A (automatic) of the rotary switch 80, the starting gear and all other gears are preselected by the electronic control unit 10, and the gear shift is only possible via the

Clutch pedal 82 triggered in connection with the trigger switch 81, the completion of the gear shift in the transmission on the clutch pedal 82 being noticeable via a signal transmitter 11. To inform the driver, an optical gear indicator 12 is also arranged, in which the gear currently engaged is shown as a number and the advantageous gear determined by the electronic control unit in the form of upshift and downshift symbols. An electronic tachometer 89 completes the information for the driver, and a load sensor 130 on the accelerator pedal 13 transmits its information to the electronic control unit IQ. The compressed air is supplied via the compressed air connection 3 and the line 85 for the solenoid valves in the central valve block 4. The actual one The gears in the transmission are shifted via the actuating cylinder 2, the position of which is controlled by the solenoid valves in the central valve block. The pressure medium supply, as a so-called general compressed air system 6 of the vehicle, is installed in it independently of the switching system and has a compressed air tank 61 with a compressed air cleaner and water separator 62.

2 shows the pneumatic emergency switching arrangement as an alternative to the compressed air supply during normal operation. 4 is the central valve block with the compressed air connection 31, via which all solenoid valves 41 to 48 are supplied from the general compressed air system 6 in normal operation. The solenoid valves 41 to 48 are switched by the electronic control unit 10 and possibly in connection with the preselection switch 8 and rotary switch 80 and tip switch 800. If the electrical system fails, there is no possibility of conveying compressed air to the actuating cylinders for switching the transmission in this way. In such a situation, an emergency switching valve 9, which is designed as a multi-position valve, supplies selected actuating cylinders 21 to 24 with compressed air. In a multi-speed transmission with a 4-speed basic transmission, a group transmission for doubling the gears of the

Basic gearbox and a GV gearbox (splitter), with which the 8 forward gears from the basic and group gearbox are doubled again, are just 4 actuating cylinders, if, as necessary, the neutral position for starting the engine, the reverse gear and two make sense selected forward gears, e.g. B. wants to switch to 1st and 3rd gear in an emergency switching program. For this purpose, changeover valves 5 "3 are arranged in the supply lines 410, 420, 440 and 460, which lead from the solenoid valves 41A, 42, 44 and 46 to the neutral positions and to one of the end positions of the actuating cylinders 21, 22, 23, via a second one Compressed air line 410/1, 420/1, 440/1, 460/1 and via these shuttle valves, the adjustment of the actuating cylinders mentioned can be in the neutral position and for e.g. the lower gears 1/5, 3/7 and for the R .-Gear in the actuating cylinder 23. The actuating cylinder 24 required for the emergency shift for the clutch shift in the slow range L is made possible by the arrangement of a shuttle valve 53 in the supply line 470/1 in the group switching valve 58 and is effected via the second compressed air line 410 / 2nd

The emergency switching valve / multi-position valve 9 is supplied with compressed air from or via a second compressed air source 7 and the second compressed air connection 32 directly or via a first safety valve 55 which, when the clutch is open - not shown - enables the passage of compressed air. The second compressed air shaft 7 can be filled by the general compressed air system 6 via a check valve 59. But it is also a filling completely independent of this general compressed air system, e.g. B. via a hand pump 72, possible. And finally, it is also conceivable to use the second compressed air connection 32 Compressed air source, possibly also a source other than the vehicle. If the use of the emergency switching device is to be guaranteed only when the vehicle is at a standstill, it is possible to supply the compressed air to the emergency switching valve 9 only via another

Allow safety valve 56 that is only open when the handbrake is applied. If an emergency shift is provided with this second safety valve 56, two forward gears cannot be shifted in succession. It is then only possible to use one of the possible forward gears, e.g. B. to select the first or third gear, for starting and driving in the forward direction. The multi-position valve 9, which acts as an emergency switching valve, has, for. B. five positions, namely the off position 92, in which all second compressed air lines 410/1 and 410/2, 420/1, 440/1 and 460/1 are vented and thus the supply of the actuating cylinders 21 to 25 via the solenoid valves 41 to 48 including 41A, 47A, 48A and the general compressed air system 6 of the vehicle over the first

Compressed air connection 31 takes place. In the neutral position N - the second position 93 - the second compressed air lines 410/1 and 410/2 are pressurized. The changeover valves 53 arranged in this line jump over - not shown - and the actuating cylinders 21, 22 and 23 are adjusted to the neutral position via the second half of the supply line 410 or are held in this position. The group actuating cylinder 24 is moved into the slow position L via the second part of the supply line 470/1. The second compressed air lines 420/1, 440/1 and 460/1 are vented in this neutral position, wherein the engine of the vehicle can be started in this neutral position. The next two positions I and II, ie 94 and 95, are assigned two forward gears, via I the second compressed air line 420/1 and the supply line 420 are acted on, so that the three-position cylinder 21 into the Gear position Gl; G5 is adjusted. Since the

Group actuating cylinder 24 is in the L position - slowly - is the first gear z. B. inserted for starting. If only the first safety valve 55 is arranged, which is mechanically connected to the clutch, it is possible to switch a further gear via the multi-position valve 9 after starting by actuating the clutch again - position II - with the z. B. via the compressed air line 440/1 and the supply line 440, the lower position G3; G7 of the pressure position cylinder 22 is switched so that the third gear is engaged. The lines not acted upon are vented, as already explained for position N neutral. Since a vehicle is also in emergency operation

In a further position 96 of the multi-position valve 9, the second compressed air line 460/1 and the supply line 460 must be connected to the reverse gear position of the actuating cylinder 23 so that a reverse travel is possible after the clutch has been engaged. In each position 93 to 96, except for the off position 92 of the multi-position valve 9, only one of the compressed air lines 410/1, 420/1, 440/1 and 460/1 arranged in this example is connected to the second compressed air source 7, while the other two compressed air lines are vented via the multi-position valve 9. To accelerate a shift, quick exhaust valves 54 can also be arranged in the area of the four forward gears in the basic transmission in connection with the actuating cylinders 21 and 22 and the supply lines 420, 430, 440 and 450. Furthermore, quick exhaust valves 54 can also be arranged in the two feed lines for the fast S group and the slow L group from the solenoid valve 47A in the group switching valve 58 to the group actuating cylinder 24 for the same purpose. The configuration of the multi-position valve 9 for turning for the active positions N, I, II, R in a second is advantageous axial plane, which is set by pressing the control knob 97. The fact that the off position 92 is housed in a first level, in which the adjusting knob is not pressed, results in a high level of security against unintentional adjustment of the

Emergency switching valve 9. For safety reasons, an electrical switch 98 can also be arranged in the multi-position valve 9, which is only closed in the off position of the multi-position valve and is open in all other positions and thus the electrical one

Supply of the electrical control - electronic control unit 10, preselection holder 8 and

Solenoid valves 41 to 48 - interrupts. The electrical switch 98 can also be set up for three positions, the second position then being the neutral position of the

Emergency switching valve 9 corresponds and allows the engine to start. In the middle position, which is assigned to the positions R, I, II of the emergency switch 9, circuits of normal operation, as already described, but also starting the engine are not possible. In connection with the electronic control unit 10 are still

Speed sensors 14, 15 for the transmission input speed and arranged in connection with the electronic speedometer 89 for the transmission output speed.

reference numeral

1 change gear

2 actuating cylinders (general) 21 3-position actuating cylinders

22 3-position actuating cylinder

23 2-position control cylinder for neutral N and

Reverse R

24 2-position actuating cylinders for group transmissions with position L slow,

S Fast

25 2-position actuating cylinder for GV (split)

3 compressed air connection

31 first compressed air connection 32 second compressed air connection

4 central valve block 41, 41A solenoid valves

42 to 46 solenoid valves

47, 47A solenoid valves 48, 48A solenoid valves

410, 420 to 480 supply lines

410/1, 12 second compressed air line

420/1 second compressed air line

440/1 second compressed air line 460/1 second compressed air line

5 valve

53 shuttle valve

54 Quick exhaust valve

55 safety valve - clutch - 56 safety valve - handbrake -

57 line

58 group switching valve

59 check valve

6 general compressed air system of the vehicle 61 compressed air tank

62 Compressed air cleaner with water separator

7 second compressed air source / compressed air tank 72 hand pump

8 pre-selection switch 80 rotary switch 00 toggle switch 81 trigger switch

82 clutch pedal

83 electrical line 85 line

9 Emergency switching valve / multi-position valve 92 Off position

93 neutral position N

94 first forward driving position I

95 second forward driving position II

96 Reverse position R 97 control knob

98 electrical switches

10 electronic control unit

11 signaling devices

12 optical gear indicator 13 accelerator pedal 30 load sensor

14 speed sensor

15 speed sensor

I first forward gear position I second forward gear position

R reverse gear position

N neutral position L slow group

S quick group

Claims

Expectations

1.Electro-pneumatic switching system for a change gearbox (1), in which the gear shifting, which is controlled by solenoid valves (41 to 48), takes place pneumatically via actuating cylinders (2, 21 to 25), with the solenoid valves (41 to 48) or the central valve block (4), in which the solenoid valves are combined, are supplied via a compressed air connection (31) and in an emergency switching operation the compressed air is fed directly to a selection of actuating cylinders (2) via a separate switching valve (9) , characterized in that a second compressed air source (7) is arranged and connected to a separately arranged multi-position switching valve (9) ^' and that the actuating cylinders (21, 22, 23, 24) for the neutral position (N) and the gears of the emergency circuit (R , I, II) via shuttle valves (53) via this multi-position switching valve (9) are pressurized and also vented.

2. Electro-pneumatic switching system according to claim 1, characterized in that the second pressure medium source (7, 32) via a short, non-branched lines (57) with the multi-position switching valve (9) connected compressed air tank (7) via a check valve ( 59) is connected to the general compressed air system of the vehicle (6).

3. Electro-pneumatic switching system according to claim 2, characterized in that the second pressure medium source (7) is connected to a hand pump (72) for generating pressure medium.

4. Electro-pneumatic switching system according to claim 3, characterized g e k e n n z e i c h n e t that the compressed air to the multi-position switching valve (9) is fed only via one (55) or more safety switching valves (55, 56).

5. Electro-pneumatic switching system according to claim 4, characterized in that this first safety valve (55) is mechanically connected to the starting and switching clutch (82) and is only open when the clutch is open.

6. Electro-pneumatic switching system according to claim 5, characterized in that a second safety valve (56) is connected to the hand brake lever and is only opened when the hand brake is actuated.

7. Electro-pneumatic switching system according to claim 1, characterized g e k e n n z e i c h n e t that in a first the off position (92) of the multi-position switching valve (9) all compressed air lines to the shuttle valves (53) are vented.

8. Electro-pneumatic switching system according to claim 1 and a change gear (1) which is formed with a 4-speed basic transmission and at least one two-speed group transmission, characterized in that in a second neutral position N (92) of the multi-position switching valve (9) all at the Actuating cylinders (21 to 24) involved in the emergency circuit are supplied with compressed air via the shuttle valves, so that the 3-position cylinders (21, 22) of the basic transmission are in the neutral position of the 2-position cylinders for R. gear (23) in the neutral position (N. ) and the 2-position cylinder (24) for the group changeover to the slow group (L) is adjusted and that in a third position (94) for a first forward gear (I) a first 3-position cylinder (21) is supplied with compressed air and in a Switch position for the z. B. first gear is adjusted, and that in a fourth position (95) for a second forward gear (II) a second 3-position cylinder (22) is supplied with compressed air and in a switching position, for. B. is adjusted for the 3rd gear and that in a fifth position (96) for the reverse gear

2-position cylinder (23) is moved into the reverse gear position (R).

9. Electro-pneumatic switching system according to claim 8, characterized in that a quick exhaust valve (54) is arranged in the feed line for the two gear shifts in the 3-position actuating cylinders (21, 22), with which the venting of the Actuating cylinder is accelerated.

10. Electro-pneumatic switching system according to claim 8, characterized in that an electrical switch (98) is arranged in the multi-position switching valve, which is closed in the off position (92) and open in the other positions (93 to 96).

11. Electro-pneumatic switching system according to claim 10, characterized in that the off position (92) in the multi-position valve (9) in a first axial plane and the other positions (93 to 96) are in a second axial plane and in that a pressed and turned control knob (97) the neutral position N (93) and the forward and

Reverse gear positions I, II, R (94 to 96) can be set.