FR2464848A1 - SAFETY DEVICE FOR MULTI-REPORTING GEAR BOXES WITH ELECTRONIC-HYDRAULIC CONTROL - Google Patents

Abstract

THE PRESENT INVENTION CONCERNS A SAFETY DEVICE FOR A MULTI-STAGE GEARBOX WITH ELECTRONIC-HYDRAULIC CONTROL. IT INCLUDES A HYDRAULIC CONTROL UNIT 1 AND A HYDRAULIC CONTROL UNIT 2, THE ELECTRONIC CONTROL UNIT CONTAINING A MEMORY 3 FOR STORING DETERMINED VALUES. IT IS CHARACTERIZED IN THAT THE HYDRAULIC CIRCUIT INCLUDES A PRESSURE SWITCH 10 PROVIDED WITH AN ELECTRICAL CONTACT 11 CORRESPONDING TO EACH CLUTCH. THE STATUS OF THIS SWITCH IS TRANSMITTED TO COMPARATOR 5 AND COMPARED TO CONTROL PULSES PROVIDED BY ELECTRONIC CONTROL UNIT 1 AND HYDRAULIC CONTROL UNIT 2. WHEN AN ERROR IS OBSERVED, THE SUPPLY VOLTAGE IS CUT. THIS DEVICE IS INTENDED FOR ROAD VEHICLES.

Description

The present invention relates to a safety device for a

  gearbox with several stepped gears, electronically controlled

  for a vehicle comprising an electronic control unit equipped with a programmable memory for storing determined values, a plurality of output amplifiers and a comparator. The electronic-hydraulic controls for multi-stage automatic gearboxes, with several clutches and brakes, must meet very high safety requirements, since in this drive system only a predetermined number

  clutches and brakes - for example two - can be simultaneously

  lawful. Similarly, only a few predetermined combinations of

  clutches and brakes are acceptable. If a number larger than the acceptable number of clutches and brakes or unanticipated combinations of simultaneous engagement of brakes and clutches is activated, it may result in a blockage of the gearbox, which may damage the gearbox.

  the latter and to create dangerous situations for road traffic.

  tier. However, the output of the control signals from the

  electronic device by known electronic means, and when

  appearance of unacceptable situations, to trigger the supply voltage.

  By these measures, it is possible to prevent a blockage of the drive system

  staged ports due to incorrect activation of clutches and / or brakes.

  However, this measure has the disadvantage that the hydraulic control part of these drive devices is not monitored and is not provided with a safety. In fact, if an error appears in the hydraulic control part, it is not recorded by the unit

  electronic control system, so that no compensatory measure is

  cated. As a result, a possible blockage of the gearbox can occur

  produce with all the consequences summarized above.

  The present invention proposes to provide a safety device

  for a multi-stage gearbox with electrically controlled

  tronic-hydraulic, which controls the output of the electrical control

  as well as that of the hydraulic control device, which triggers

  check the supply voltage at the occurrence of an error or

  detection of an inadmissible state. This safety device should preferably

  this show that a very small increase in the size of the electronic device, in particular as regards the cabling between the unit of

  electronic control and hydraulic control unit.

  This object is achieved by the device according to the invention, characterized in that the hydraulic circuit comprises a pressure switch provided with 2_

  of an electrical contact and corresponding to each clutch, the state of this

  mutator being transmitted to the comparator and compared to control pulses

  supplied by the electronic control unit, the hydraulic control unit

  The comparator is arranged to transmit control pulses to a device for triggering the supply voltage of the hydraulic control unit when it discovers an error.

  Complementary inclusion in the monitoring system of the

  The advantage of the hydraulic control unit is that the electronically-controlled, multi-stage gearbox has a

  high level of security, since the detection of errors at the level of

  electrical and / or hydraulic systems, results in a triggering of the

  power supply, which prevents a possible blockage of the bibi-

  speed. By the appropriate introduction of electrical switching

  tronic, we can abandon the installation of relatively

  between the electronic and hydraulic control units, the wiring does not

  as very little developed between the two control units, by the

  troduction of the device according to the invention.

  The present invention will be better understood with reference to the

  description of embodiments and appended drawings in which:

  Fig. 1 is a view schematically illustrating the unit of communication

  electronic dial comprising a comparator, and a part of the hydraulic control unit provided with a pressure switch for transmitting a signal corresponding to the instantaneous state of a switching and pressure control valve to the control unit. electronic control, Fig. 2 shows another schematic view similar to that of FIG. 1, however, comprising a complementary memory included in the electronic control unit and provided for storing information corresponding to the acceptable combinations of engagement of the clutches and the brakes of the gearbox, FIG. 3 is a schematic view of the operation of the error detection device, and FIG. 4 shows a circuit diagram connecting different push switches, whose instantaneous state is transmitted to the unit of

  electrical control via a single power line.

  A hydraulically controlled, multi-stage gearbox has parallel control circuits for

  engaging the clutches and brakes of the corresponding gear.

  Fig. 1 represents, for the sake of simplification, only one switching control valve 9, the gearbox comprising

  moreover, a series of such circuits.

  The switching valve for the pressure control 9 is

  controlled by an amplifier, via a conduit 6, a

  magnetic poppet 7 and a pre-control valve 8. This amplifier is part of an amplification unit 4, and the number of such amplifiers

  corresponds to the number of switching and pressure control valves.

  A constant-value memory (PROM) transmits control signals to the input of the amplification unit 4, via a conduit 16.

  corresponding control signals are transmitted over a line 18 from

control elements of functions.

  For the control of the amplification unit 4, the signals,

  at the exit of this unit, are transmitted by a line 15 to a

  paratridge 5 connected by another line 13, to the input of the amplification unit, for the purpose of comparing the output signals. Fig. 1 represents only one line

  15, drawn in broken lines. Depending on the number of amplification phases

  the device will have a corresponding number of lines 15 for the over-

  monitoring the individual outputs of the amplification unit.

  tions, transmitted via line 13 and one of the corresponding lines 15

  Compared to the comparator5, do not coincide, the comparator 5 emits a signal at the output 14. This signal is used to trigger the supply current. Of

  the comparator makes it possible to constantly check the operating status

  of the amplification unit 4.

  To also check the operating status of the clutches

  and brakes, we use their hydraulic circuits. To detect pres-

  in the clutch and brake circuits, each control valve

  The pressure control unit 9 comprises a push-button switch 10

  individual, equipped with an electrical contact 11. The electrical contact of the

  The pushbutton 10 is in two positions, corresponding to the switching on and off, one of the connection terminals being connected to a determined voltage (not shown) and the other connecting terminal being connected by the line 12. to the comparator 5. As a result, the comparator 5 is able to compare the control signals, appearing at the input of the amplification unit 4, with the information transmitted by the corresponding line.

  12. The corresponding line 15, for the control of the output of the unit of am-

  4, can be suppressed, because the comparator 5 retransmits information about the present state of the switch 10 and therefore the relative state of the pressure control valve 9. The comparator 5 compares this information retransmitted with the command on and determines whether or not there is an error. In this case, a corresponding signal is transmitted by

  a line 14, to a device arranged to cut off the supply voltage.

  4- Although according to the device described, the amplification unit 4 is constantly under control, it may happen that following a lack of signals

  theoretically transmitted by the determined-value memory 3 (PROM), the change in

  safety gear can fail, since this memory also engages the comparator 5. Therefore, the exchange device

  According to the invention, a further embodiment of the invention

refers to FIG. 2.

  According to this embodiment (FIG 2), the control unit hy-

  2 remains unchanged, the electronic control unit1, on the other hand,

  supplemented by a supplementary memory 19. This memory is intended for

  store the allowable combinations of clutches and brakes, activated

  simultaneously in the gearbox. It can also register the name

  maximum number of clutches and / or brakes activated simultaneously. Thanks to the

  In a memory 19, it is no longer necessary to maintain the information appearing at the input of the amplification unit 4. Feedback is transmitted via the corresponding line 12 (FIG. corresponding pusher 10 and its appropriate connection terminal 11, to the comparator 5,

  to indicate the state in which the switching and

  9. The delivered value is compared to the values correspon-

  stored in memory 19, and the comparator determines whether a

  correct combination, a combination allowed, a combination that is false or

  sible is generated. If no false or invalid combination does not appear, the comparator provides no signal. On the other hand, if a false or inadmissible combination appears, the comparator 5 generates a signal transmitted by its

  output 14 to a device arranged to trigger the supply voltage.

  When a false or inadmissible combination occurs, or when the

  number of activated clutches is greater than the maximum number, all clutches

are triggered.

  Thanks to the use of the complementary memory 19, we obtain

  separate monitoring of the output amplification unit 4, by means of a

  control of the instantaneous values appearing at the level of the push switches.

  10 and their connection terminals 11. Since the comparator 5 receives these reference signals from the memory 19, the gearshift device can not be switched off, when the fixed value memory

3 breaks down.

  The timing diagram of FIG. 3 makes it possible to understand the

  provision of error detection devices. It will be assumed that according to diagram A, the current in the magnetic valve 7 (Fig. 1, 2) is cut off at time TO. At this time, the magnetic valve must no longer be activated,

  so that the pressure in the clutch should, after a time of rela-

  system-specific, go back to zero. In addition, it will be admitted that

  of a time T1 for the control of the push switch 10. If, according to the di-

  gram B, the pressure transmitted to the clutch by the push switch 10 lasts during the time interval T1 - in FIG. This time is represented by T2 -, then a defection signal is determined during the time T1 corresponding to the control of the push switch 10. The transmission of this defection signal to the safety device is done with a certain delay, represented by the time interval T3 in FIG. 3. The time delay for transmission to the safety device shall be determined in such a way that the inertia of the system, and in particular the pressure drop generated by the triggering of the magnetic valve 7, does not result in activation of the safety device . If the clutch pressure remains constant, as

  shows the diagram C of fig. 3, the magnetic valve not being de-

  triggered, a signal of defection transmitted by the

  10 and its connection terminal 11, to the comparator 5.

  Line 6 (FIG 1, 2), arranged between the amplification unit 4 and

  the different magnetic valves 7, must be reproduced in several

  depending on the number of clutches used. For questions of

  clarity of the drawing, only a line 6 is shown. For example, when

  that seven clutches are used, seven lines 6 are necessary. Line 12, for

  the return of the information provided by the push-button switch 10 and corresponding

  spanning the hydraulic pressure of the clutch, can be a single line, which reduces the number of lines to be laid and the number of connection pins. For this purpose, a circuit shown in more detail is used.

in fig. 4 described below.

  As mentioned previously, the control unit 1, described in FIG. 1, uses the comparator 5 to compare the information appearing at

  the input and output of the amplification unit 4, and to determine whether the

  amplification of the output signal is in good condition. According to FIG. 2, the comparator 5 and the auxiliary storage unit 19 of the control unit

  electronics 1 allow, by measurement of the output signals of the unit of am-

  4, to determine whether the maximum number of clutches activated simultaneously

  is exceeded, or if the appropriate combination of clutches and brakes is possibly false. The hydraulic control unit 2 (Figures 1 and 2) is tested by determining whether the signal, corresponding to the state of the pressure in the drive, is identical to the signals supplied by the drive unit. amplification 4 by the lines 6 and transmitted to the magnetic valves 7. This

  verification is carried out individually for each clutch. If the

  has recognized that the correct clutch, ie the maximum number

  clutches or combinations, etc., is activated by unit 6.

  4, and if the push switch 10 has signaled the state of the pres-

  corresponding to comparator 5, and if finally we find the. corresponding

  the signals transmitted by the electronic control unit 1 with those transmitted by the push-button switches 10, it can be estimated that the pressure conditions in the drive device are in conformity with those which had

have been solicited.

  The circuit represented by FIG. 4 serves to compare the control signals, transmitted to the hydraulic control unit and therefore also to the gearbox, by the electronic control unit 1, via the line 6, under the conditions of actual pressure prevailing in the gearbox. This circuit, as shown in FIG. 4, comprises the amplification unit 4 equipped with contacts 38, 39, 40, which are connected, by one of their connection terminals, to a voltage source of + 24 V and, by their other connection terminal, to coils of the magnetic valves 7, 37, 47, these same terminals being used to connect the cathodes of diodes

  32, 33, 34. The anodes of these diodes are connected to a terminal of each

  tact 11, 31, 41, which represents. push-button switches 10. The other

  connection of the contacts 11, 31, 41 of the push switches are

  connected to the comparator via line 12 (see Figures 1 and 2).

  The latter comprises an organetétecteur 20, which is also connected to the voltage source by a line 35. The detector member 20 transmits, in this example

  embodiment, a voltage of + 5V in line 12. If one or more of the

  tacts 38, 39, 40 of the amplification unit 4 are closed, a current corresponding to

  by the coil of the magnetic valve 7, 37, 47, the diodes 32, 33, 34 are blocked, independently of the fact that one or more of

  contacts 11, 31, 41 of the push switches 10 are open or closed.

  On the other hand, if the contact 38 of the amplification unit 4 is

  green, - the magnetic valve 7 not in this case not to be activated -, the contact 11 of the switch 10 shows, because it is closed, that a corresponding pressure prevails in the clutch, and the current flows in the line 12

  by the closed contact 11 and the diode 32, through the coil of the manual valve

  gnetic 7, the second contact terminal is connected to ground. The or-

  gane detector20determines if a clutch is activated.

  If, for example, all the contacts 38, 39, 40 of the amplifier unit

  4 are open, and the contacts 11, 31, 41 of the switches 10 are

  closed, the current flowing in line 12 is higher than that

  mined by the sensor member 20 of the comparator 5, since three clutches are

  simultaneously solicited. If it is planned to limit the device to

  two clutches simultaneously, the safety device is activated. This

  proves that only one line 12 is needed to determine, depending on the

  7. Current Tensity, if multiple clutches are simultaneously activated, while this should not be the case based on the output signals transmitted by

the amplification unit 4.

  If, by way of example, the contact 38 of the amplification unit 4 is closed, and if the pressure is not sufficient at the corresponding clutch, then the contact 11 of the push switch 10 does not close, which is also a mistake. This error would not be transmitted by

  line 12 to the detector 20 and to the comparator 5. However, this

  false training does not constitute a very serious risk for the speed box.

  because it can not in any way cause a blockage of this

Niere.

  The opening of the previously closed contact 38 of the amplifier unit

  cation 4 interrupts the activation of the coil of the magnetic valve 7.

  The appearance of the pressure, in the ducts corresponding to this clutch, can not immediately follow the power cut in this coil. To

  that the safety device is not immediately engaged after the

  pure current, the current detector 20 is connected by means of a

  25 to a delay device 21, which will transmit the error signal,

  by a line 26, to a safety device.

  The error signal is transmitted via line 36 to a two-way flip-flop.

  stable 22, which is able, at a given moment, to take this error signal

  and memorize it. It receives, by another line 27, a reference signal.

  The purpose of this feature of the circuit is to obtain information about

  prevents any change in the pressure in each clutch,

  control, at least temporarily, of the efficiency of the operation of

  pushers. It would be possible to connect a device signaling the failures of the push switches via a line 28, an amplifier 23 and a line 29. q 8.

Claims (8)

  1. Safety device for a multi-gearbox   gear ratios, with electronic-hydraulic control, for a vehicle with   both an electronic control unit equipped with a programmable memory for storing determined values, a plurality of output amplifiers and a comparator, characterized in that the hydraulic circuit comprises a pressure switch (10) provided with an electrical contact ( 11) and corresponding to each clutch, the state of this switch being transmitted to the comparator (5)   and compared to control pulses provided by the control unit e-   (1), the hydraulic control unit (2), the gearbox   in that the comparator (5) is arranged to transmit pulses   control devices to a device to trigger the supply voltage of   the hydraulic control unit (2) when it discovers an error.   Device according to Claim 1, characterized in that the comparator (5) uses the control pulses transmitted by the electronic control unit (1) as reference signals, these pulses being   available directly at the output of the memory (3).   3. Device according to claim 1, characterized in that the comparator (5) uses information provided by an auxiliary memory (19). 4. Device according to claim 3, characterized in that the   auxiliary memory (19) stores the largest permissible number of   activated clutches, and / or the largest number of unacceptable combinations brakes and clutches.   5. Device according to claim 4, characterized in that the in-   training regarding the largest permissible number of clutches action-   and / or the largest unacceptable number of combinations of brakes and clutches, is compared to the control pulses in the comparator (5),   these pulses appearing at the output of the electronic control unit (1).   6. Device according to any one of the preceding claims   tes, characterized in that a plurality of contacts (11, 31, 41) of the switches (10) are respectively connected to the connectors by one of their members   connection and a single line (12), while the other   each of these contacts (11, 31, 41) is connected to the inputs of   corresponding magnetic valves (7, 37, 47) via   respective diodes (32, 33, 34), these magnetic valves being   by the electronic control unit (1).   7. Device according to any one of the preceding claims   characterized in that the error signal is transmitted to a 39 timer. 9.   8. Device according to any one of the preceding claims   characterized in that the error signal is transmitted, with a signal of   3 reference, to a flip-flop (22).