IT8046877A1 - SAFETY DEVICE FOR ELECTRONIC-HYDRAULIC GEAR CHANGEOVER FOR VEHICLES - Google Patents

Description

DESCRIPTION

of Industrial Invention Patent for the invention entitled: "SAFETY DEVICE FOR ELECTRONIC-HYDRAULIC CONTROL IN-GEAR GEAR FOR VEHICLES",

SUMMARY

Safety device for electronically-hydraulically controlled gearboxes for vehicles comprising a unit? control electronics that has a programmable constant value memory, a plurality of of amplifiers and a comparator and in which also? provided that in the hydraulic circuit of each clutch there are two pressure switches individually equipped with an electrical contact (11) / whose switching states are transmitted to the comparator (5) and compared by the latter by means of pulses command transmitted by the unit? control electronics (1) to the unit? control hydraulics and in which? provided that the comparator (5), detecting an error, transmits command pulses to a device for interrupting the power supply voltage for the unit? control hydraulics (2).

TEXT OF THE DESCRIPTION

The invention relates to a safety device for an electronically-hydraulically controlled gearbox for vehicles with a single unit. control electronics, which has a programmable constant value memory, a plurality of of output amplifiers and a comparator.

The electronic-hydraulic controls for automatic gearboxes with a plurality of of clutches and brakes must meet considerable safety requirements, since in such changes only a certain number of clutches and brakes, for example two, can? be entered.

Likewise? Only certain pre-set combinations of clutches and brakes can be inserted. If more clutches and brakes are commanded than allowed or if unauthorized combinations of clutches and brakes are commanded, it can? derive a lockout of the gearbox, consequently causing possible damage to the latter and dangerous situations in vehicle traffic. By means of known measures? Is it possible, in the event of inadmissible operating conditions, to monitor the functionality? of the control electronics at its output and interrupt the power supply voltage at the output. They could make it possible to avoid susceptible incorrect insertion of clutches and / or brakes on the gearbox and therefore the blocking of the latter.

Stay for? the disadvantage that the hydraulic control part is not n? supervised n? insured. In fact, if an error occurs in the hydraulic control part, n? the unit? control electronics, n? the safety device that monitors it records it and therefore cannot? no suitable countermeasure be in place. There is therefore always the possibility? that a block of the exchange occurs with all the possible negative consequences already? mentioned.

The present invention therefore has the task of creating a safety device for an electronically-hydraulically controlled gearbox which monitors the output of the unit. control electronics extending this surveillance also to the hydraulic control part and that interrupts the electric power supply in the presence of an incorrect operating condition. The safety device should be made with a greater and possibly reduced cost for the control electronics and as regards its wiring respectively with the unit? control electronics and with the hydraulic one.

The further extension of the monitoring to the hydraulic control part offers the advantage of being able to apply an electronically-hydraulically controlled gearbox with considerable operational safety and that faults in the electronic and / or hydraulic control cause interruption of the supply voltage. , effectively avoiding a blocking of the gearbox. Thanks to the skillful application of electronic contact elements you can? renounce costly circuits between the electronic control unit and the hydraulic control unit so that the wiring between the two units? command will require? only a small enlargement.

Further advantageous elaborations can be found in the secondary claims.

The invention is illustrated with drawings on the basis of executive examples.

FIG. 1? the schematic representation of the unit? control electronics with a comparator as well as? of a part of the unit? hydraulic control with a pressure switch for the feedback to the unit? electronic control of the operating condition of a maneuver and pressure control valve.

FIG. 2 ? a further schematic representation, similar to that of FIG. 1, but with an additional memory in the unit? control electronics for memorizing permitted combinations of clutch and gearbox brakes engaged.

FIG. 3? the scheme of the time course for the recognition of a fault.

FIG. 4? the wiring diagram of the connection of a plurality? of pressure switches, whose operating conditions are signaled to the unit? control electronics by means of a single electrical circuit.

A hydraulically electronic-hydraulic gearbox has parallel control circuits for controlling the clutches engaged in the individual gears and the brakes. In order to simplify the representation, FIG. 1 shows only a changeover and pressure control valve (9), even if the gearbox? provided with a plurality? of similar control circuits.

By means of a conduction (6), a magnetic valve (7) and a pilot valve (8), the switching and pressure control valve (9) is driven by an output amplifier, a quantity of which, according to the number of switching and pressure control valves,? enclosed in a unit? amplifier output (4). At the entrance of the unit? of output amplification (4) are supplied by means of a conduction (16) from the output of the constant value memory (3) (PROM) of the command signals. For this purpose, the associated control signals are supplied by means of a conduit (18) from function elements.

For the control of the unit? of output amplification (4) the signals that appear at the output of the same by means of a conduction (15) are adduced to a comparator (5) which by means of a further conduction (13) compares the input of the unit ? of output amplification with the output of the same. FIG. 1 shows only one conduction (15) with dashed line.

In accordance with to the quantity of amplifier stages you need the corresponding quantity of conduction (15) for the monitoring of the single outputs of the unit? amplifier output (4). In the event of a mismatch of the information contents that are supplied to the comparator (5) by means of the conduction (13) and the respective conduction (15), a signal is created at an output (14) of the comparator (5). The latter is used for interrupting the power supply. In this way, only the operating condition of the unit is checked with the comparator. amplification. To detect the operating conditions of the clutches and brakes, the hydraulic circuits of the same are monitored. For pressure sensing for clutches and brakes, a pressure switch (10) which has an electrical contact (11) is attached to each changeover and pressure control valve (9). The contact (11) of the pressure switch (10)? an on / off switch, a hookup of which? placed at a certain electric potential (not shown in the drawing), while the other connection? connected to the comparator (5) by means of a conduction (12). Therefore the comparator (5)? able to compare the command signals at the entrance of the unit? output amplification (4) with the information content of the corresponding conduction (12). Its conduction (15) for monitoring the output of the unit? of output amplification (4) pu? be omitted, since the comparator (5) is provided with a back signal of the actual condition of the relative pressure switch (10) and therefore of the relative switching and pressure control valve (9). The comparator (5) compares this feedback with the desired setting and decides if yes? if there is an error. In the event of an error, the relative signal is transmitted by means of a conduction (14) to a device which interrupts the supply voltage.

Even if with the device described here a continuous control is exercised on the unit? of output amplification (4), pu? it may happen that if the signals supplied by the constant value memory (3) (PROM) are missing, the safety circuit is also put out of service, since the constant value memory (3) (PROM) also drives the comparator ( 5).

Therefore, the described safety circuit is extended by means of a further embodiment described on the basis of FIG. 2.

In this enlarged executive example (FIG. 2) the unit? control hydraulics (2)? unchanged, while the unit? control electronics (1)? been extended with the addition of a memory (19). This ? intended for additional storage of permitted combinations of clutches and brakes controlled in the gearbox. It can? also memorize the maximum quantity of clutches and / or brakes to be driven. Thanks to the use of memory (19) not? pi? necessary to detect at the entrance of the unit? output amplification (4) the information content that appears therein. In fact, through the relative conduction (12) (FIG. 2) there is a back signal to the comparator (5) by the pressure switch (10) concerned and by the relative contact (11) about the operating conditions of the control valve switching and pressure (9). The value supplied is compared with the value stored in the additional memory (19) and the comparator (5) finds, if yes? in the presence of a permissible combination, an incorrect illegal combination or an attached incorrect combination.

If not? in the presence of an illegal, incorrect combination, the comparator does not give? no signal. If, on the other hand, yes? in the presence of an illegal, incorrect combination, the comparator sends, through its output (14), a signal to a device for interrupting the supply voltage. In the event of an illegal or incorrect combination, or if a number of clutches exceeding the maximum permitted quantity are piloted, all clutches are released.

Thanks to the use of the additional memory (19) it is no longer? need a separate surveillance of the unit? output amplification (4), as its monitoring occurs simultaneously with the monitoring of the real values at the pressure switches (10) and the relative contacts (11). Since the comparator (5) detects its reference signals from the memory (19), the safety circuit is not taken out of service in the event of a fault in the constant value memory (3) (PROM).

The diagram of FIG. 3 indicates the time course for the detection of a disturbance. Let us suppose that according to diagram A the current of the magnetic valve (7) (FIGS. 1 and 2) is interrupted at the instant T. From this moment on, therefore, the magnetic valve will not have to? pi? be piloted, the pressure in the clutch should go, with a certain time delay of the system, to zero. Let us also assume that a space of time is available for controlling the pressure switch (10) (FIG. 3). If according to diagram B the pressure in the clutch, sensed by means of the pressure switch (10), lasts beyond the space of time, in FIG. 3 there? corresponds to the time, by means of the gi? cited control of the pressure switch (10) at the expiration of time is already? detected a disturbance signal, the safety device can? to react. The reaction of the safety device occurs with a certain delay, as mentioned in FIG. 3 with time T The delay for the reaction of the safety device must be determined so that the inertia, typical of the system, of the decrease in pressure following the disengagement of the mechanical valve (7) does not cause the reaction by itself of the safety device. What if, with the solenoid valve unmanned, the pressure in the clutch? constantly present as shown in diagram C (FIG. 3), this? naturally Causes the emission of a disturbance signal to the comparator (5) by means of the pressure switch (10) and its contact (11).

The conduction (6) (FIGO. 1, 2) which conjunction between the unit? output amplification (4) and the various magnetic valves (7), must be present in a number corresponding to the quantity of clutches used.

For senrol? Cit? in the drawing only one conduction is shown (6).? If seven clutches are used, for example, seven conduits (6) must also be provided: The conduction (12.) for the back-signaling of the information given by the pressure (10) relative to the hydraulic pressure, on the other hand, can? be unique, allowing cos? a saving of circuits and plug contacts. For this purpose ? intended for a circuit as per FIG. 4 described below.

As previously stated, in the unit? control electronics, according to FIG. 1, in the comparator (5) comparing the information contents that appear at the entrance and at the exits of the unit? of output amplification (4) occurs, if the unit? of output amplification? in place, or in the unit? control unit (1), according to FIG.

2, in the comparator (5) with the addition of a further memory (19) and by means of the measurement of the outputs of the unit? output amplification (4) occurs, if the maximum permitted quantity of clutches to be entered? been exceeded, if you have the correct combinations of clutches and brakes or if, if so, yes? in the presence of incorrect combinations of clutches and brakes. The unit of hydraulic control (2) (FIG. 1, 2), as already? exposed, is checked according to the fact, if the actual pressure ratios in the gearbox correspond to the command signals supplied by the unit? output amplification (4) by means of conduction (s) (6) and intended for magnetic valves (7). This check takes place separately for each clutch. When the comparator has verified that the correct clutches have been piloted, therefore only a certain maximum quantity of clutches, the correct combinations, etc., by means of the unit? output amplification (4) and when the pressure switches have communicated to the comparator (5) the relative pressure ratios and if a correspondence is found between the signals emitted by the unit? control unit (1) and the information obtained from the pressure switches (10), can you? assume that the desired gearbox pressure ratios are also correct.

The circuit as per FIG. 4 has the task of making a comparison between the command signals transmitted by the unit? of electronic control (4) by means of conduction (6) to the unit? of hydraulic control and therefore to the gearbox and the actual pressure ratios existing in the gearbox. To make this circuit clearer, in the unit? of output amplification (4) (FIG. 4) contacts (38), (39), (40) are represented, one connection of which? connected to the 24 V supply voltage and whose other connections lead to the windings of the magnetic valves (7), (37), (47), being on the same connections as the magnetic valves (7), (37), (47) connected the cathodes of the diodes (32), (33), (34). The anodes of these diodes lead to the connection of each single contact (11), (31), (41.), which constitute the contacts of the pressure switches (10). The other connections of the contacts (11), (31), (41) of the pressure switches are connected to the comparator (FIG. 1, 2) through conduction (12). This presents a current sensor (20) (FIG. 4), which through a conduction (35)? it is also connected to the 24 V supply voltage. In the executive example, the current sensor (20) supplies the conduction (12) with a voltage of. + 5 V. If one or more? contacts (38), (39), (40) in the unit? output amplification (4) are closed, for the windings of the magnetic valves (7), (37), (47) an equivalent current passes, the diodes (32), (33), (34) are closed and precisely independently from the fact, if one or more? contacts (11), (31), (41) of the pressure switch (10) are open or closed.

If ^? N instead for example the contact (38) in the unit? amplifier output (4)? open, the magnetic valve (7) therefore should not? be piloted, but the contact (11) of the pressure switch (10), as it is closed, indicates that in the relative clutch? present of the pressure, from conduction (12) and passing through the closed contact (11) and the diode (32) connected flows a current that passes through the winding of the valve magnets? c? (7), whose second connection? placed in mass. The current sensor (20) detects that a clutch? been inserted.

If for example all the contacts (38), (39), (40) in the unit? of output amplification (4) are open and the contacts (11), (31), (41) of the pressure switch (10) are closed, in the conduction (12) a current flows more? strong, which is detected by the current sensor (20) in the comparator (5) as proof that three clutches have been put under pressure. If instead ? only allowed to insert a maximum of two clutches in the gearbox, it will be? activated the safety device. Is therefore sufficient a single conduction (12) to detect on the basis of the intensity? of current of this conduction, if for example, some clutches are pressurized, even if, according to the driving by means of the unit? If there is output amplification (4), they should not be or if too many clutches are under pressure in their hydraulic circuit systems. If for example the contact (38) in the unit? amplifier output (4)? closed, but there is no pressure in the relative clutch, the contact (11) of the pressure switch (10) is not? closed and there? would result in an error.

This error would not be transmitted through conduction (12) to the current sensor (20) and consequently to the comparator (5). This lack of information would not have for? negative repercussions on the gearbox, as a disengaged clutch could not cause the gearbox to lock up.

The opening of the previously closed contact (38) of the unit? amplifier (4) (FIG. 4) interrupts the excitation of the winding of the magnetic valve (7) (FIGS.1, 2). The elimination of the pressure in the relative clutch, for own reasons of the system, can not? immediately follow the power outage, but it takes a certain amount of time. In order that, during this time, the safety device will not; reacts immediately, by the current sensor (20) (FIG. 4) through a conduction (25) the signaling of the disturbance is initially adduced to a refarding circuit (21) and forwarded from there. through a conduction (26) to the safety device.

Through a conduction (36) an error signal is also fed to a flip-flop (22) capable of detecting the error signal for a certain time and storing it for indication. Through another conduction (27) it receives a test signal. The purpose of this particularity? ? only the following: by modifying the pressure ratios in each clutch, the switch and its electrical contact should be activated, a relative safety signal would occur, at least for a short time.

Claims (9)

R I V E N D I C A Z I O N I 1) Safety device for electronically-hydraulically controlled gearboxes for vehicles equipped with a unit? control electronics, which has a programmable constant value memory, a plurality of of output amplifiers and a comparator, characterized by the fact that in the hydraulic circuit of each gearbox clutch there are pressure switches (10) each with an electrical contact (11), whose switching states are transmitted to the comparator (5) and compared by the latter with command pulses transmitted by the unit? control electronics (1) to the unit? control unit and that the comparator (5), finding an error, transmits command pulses to a device for interrupting the power supply voltage for the unit? control hydraulics (2). 2) Device as per claim 1, characterized by the fact that the comparator (5) analyzes the command pulses emitted by the unit? control electronics (1) such as reference signals to be made available directly to the constant value memory output (3). 3) Device as per claim 1, characterized in that the comparator (5) analyzes the information of a further memory (19) as reference signals. 4) Device as per claim 3, characterized in that the further memory (19) contains the maximum admitted quantity of inserted clutches and / or the unauthorized combinations of brakes and clutches. 5) Device as per claim 4, characterized by the fact that the maximum admitted quantity of pressed clutches and / or the impermissible combinations of inserted clutches and brakes are compared in the comparator (5) with command pulses that occur at the output of the unit? electronic control (1). 6) Device as per one or more? preceding claims, characterized in that a greater number of contacts (11), (31), (41) of the pressure switches (10) are placed in contact together, by means of a single conduction (1.2), with the comparator (5) through one of the respective connections, while the other connection of each of the contacts (11), (31), (41)? connected through a diode each (32), (33), (34) to the control input of each magnetic valve (7), (37), (47) piloted by the unit? control electronics (1). 7) Device according to one of the preceding claims, characterized in that an error signal is previously supplied to a delaying device. 8) Device according to one of the preceding claims, characterized in that the error signal is supplied together with a test signal to a flipflop (22). 9) Safety device for electronic-hydraulic control gear change for vehicles according to what was previously described and illustrated in the attached drawings and for the purposes specified above. Safety device for an electronically-hydraulically controlled gearbox for vehicles_ Patent claims 1. Safety device for an electronically-hydraulically controlled gearbox for vehicles equipped with a unit? electronic control, which has a programmable constant value memory, a plurality of of output amplifiers and a comparator, c a r a t t e r i z z a t o d a l f a t t o that in the hydraulic circuit of each clutch of the gearbox there are pressure switches (10) with an electric contact (11) each, whose switching states are transmitted to the comparator (5) and compared by the latter with command pulses transmitted from the unit? electronic control (1) to the unit? of hydraulic control and that the comparator (5) - detecting an error - transmits command impulses to a device for interrupting the power supply voltage for the unit? hydraulic control (2). 2. Device as per claim 1, c a r a t t e r i z z a t o d a l f a t t o that the comparator (5) analyzes the command pulses emitted by the unit? control unit (1) which reference signals cos? as available directly at the constant value memory output (3). 3. Device according to claim 1, c a r a t t e r i z z a t o d a l f a t t o that the comparator (5) analyzes the information of a further memory (19) as reference signals. 4. Device according to claim 3, c a r a t t e r i z z a t o d a l f a t t or that the further memory (19) contains the maximum permitted quantity of entered clutches and / or the unauthorized combinations of brakes and clutches. 5. Device as per claim 4, c a r a t t e r i z z a t o d a l f a t t o that the maximum permitted quantity of piloted clutches and / or the impermissible combinations of inserted clutches and brakes are compared in the comparator (5) with control pulses occurring at the output of the unit ? control electronics (1). 6. Device as per one or more? previous claims, c a r a t t e r i z z a t o d a l f a t t o that a greater number of contacts (11, 31, 41) of the pressure switches (10) are placed in contact together, by means of a single conduction (12), with the comparator (5) through one of the respective connections , while the other connection of each of the contacts (11, 31, 41)? connected through a diode each (32, 33, 34) to the control input of each magnetic valve (7, 37, 47) piloted by the unit? electronic control unit (1). 7. Device as per one of the preceding claims, c a r a t t e r i z z a t o d a l f a t t or that an error signal is previously fed to a delay device. 8. Device as per one of the preceding claims, c a r a t t e r i z z a t o d a l f a t t or that the error signal is fed together with a test signal to a flipflop (22).