DE10209100A1 - Electromagnetic clutch control in vehicle equipped with automatic transmission, disengages clutch during vehicle stoppages extending beyond set time limit by gradual reduction of clutch energizing current - Google Patents

Abstract

Engine controller (4) monitors accelerator position, brake switch status, range setting in the automatic transmission as well as the vehicle speed to ensure that the electromagnetic clutch (2) continues to be connected to the transmission unit (3). When vehicle stops for periods beyond a set duration, the clutch is disengaged by switching OFF the energizing current in a gradual manner.

Description

The present invention relates generally to a Device for controlling the electromagnetic clutch a synchronized automatic transmission system for automatic switching of a synchronized gear Multi-stage manual transmission unit, which with a Internal combustion engine connected in a motor vehicle is installed. In particular, the present concerns Invention a control device for electromagnetic Coupling of a synchronized automatic transmission or automated synchronized gearbox, which is designed heat generation of the electromagnetic clutch prevent if the motor vehicle in a long time State is stopped in which a handbrake in one Driving area or drive area is attracted, and in the one Brake switch is open (i.e. in one Kriechsteuerzustand).

As a known or conventional control device for a synchronized automatic transmission system one Internal combustion engine for a motor vehicle, for example pointed out that which is in the Japanese patent application No. 312685/1996 (JP-A-8-312685).

It is known in the prior art that a synchronized Automatic transmission has a creep function to a Creep control for an output shaft of the engine in which Perform state in which the brake pedal is depressed is (i.e. in the state of stopping).

In the case of the publication mentioned above disclosed synchronized automatic transmission system when it is recorded or decided that the electromagnetic clutch in a magnetic Connection status is, and that the motor vehicle continuously for a predetermined period or longer a disengagement signal is output to heat generation during continuous creep control avoid.

The state in which the vehicle with the magnetic connected electromagnetic clutch is stopped, usually represents the condition in which the motor vehicle is stopped with the brake pedal depressed, for example at a traffic light. However, it is also a stationary one Condition of the motor vehicle conceivable in which the motor vehicle is stopped on an incline (e.g. in front of a Level crossing), in a state in which the due to the Slope of the slope backwards on the motor vehicle acting force is balanced by the creeping force.

Consequently, when a disengagement signal is generated when stopping of the motor vehicle on the slope, as just described the forward driving force from the motor interrupted so that the vehicle accidentally backwards rolls.

Of course, the motor vehicle can be stopped by that only the side brake or handbrake is actuated without Depress the brake pedal. Accordingly, the conventional control device described in the above Publication discloses a switch or sensor for Detection of the operation of the handbrake provided in With a view to creating a control to weaken the Creep when the handbrake is applied.

As can be seen from the above, conventional ones suffer Control devices for electromagnetic clutches from synchronized automatic transmissions under the problem that in such a situation where the on a Motor vehicle rearward force when it is on a Sloping down is compensated for by the creeping force the abrupt disengagement is a backward movement of the Motor vehicle will cause when moving forward directional driving force disappears as that Disengagement signal is output when the motor vehicle a predetermined period of time in the magnetic State of connection of the electromagnetic clutch was stopped.

Furthermore, in a state in which the motor vehicle only by the effect of the handbrake is stopped Control for weakening the creep force carried out safely. For this purpose, however, the switch for detecting the Actuation of the hand brake can be provided, which increases costs and brings with it an increased mechanical complexity.

In view of the prior art described above It is an object of the present invention to provide an apparatus to control an electromagnetic clutch to create synchronized automatic transmission, which in is able to be traced back to creep control Prevent or suppress heat generation while security is maintained by preventing a motor vehicle from a stationary state on a Slope moves backwards, without increasing costs.

With regard to the above and other tasks, which in Course of the description can be seen, according to a general aspect of the present invention Device created to an electromagnetic clutch a synchronized automatic transmission or to control automated manual transmission, which is designed is to automatically switch a variety of gears in one synchronized multi-speed gear change unit, the is mounted in a motor vehicle to switch which Device includes a brake switch to a condition detect in which the brake pedal is depressed, one Area switch for recording the switching positions, including a driving area Accelerator pedal position sensor for detecting the actuation stroke of the accelerator pedal, a vehicle speed sensor to order as Vehicle speed of the motor vehicle the Output rotational speed or speed of the synchronized multi-stage gear change transmission unit too detect, and a control device or Regulation device (hereinafter the term "Control" for control and regulation alike used) for changing or switching the gear stages of the Multi-stage gear change transmission unit based on Detection signals of the brake switch, the range switch, of the accelerator position sensor and Vehicle speed sensor. The multi-stage Gear change transmission unit contains an electromagnetic Coupling to effect transmission / interruption of the Driving force at the beginning and end of changing the Gears, and a creep control. The control device contains a clutch control unit for delivery of a Excitation current to the electromagnetic clutch, the Clutch control unit is designed so that a Current command value for the excitation current from one value to Gradually effect creep control to zero amperes decreases, in the event that a condition in which the Selector lever position in open (OFF) brake switch in Driving range, and in the one Vehicle speed value of 0 (zero) km / h is specified has lasted for a predetermined period of time.

Due to the arrangement of the control device for a electromagnetic clutch of a synchronized Automatic transmission system, which was described above, can heat generation due to the creep control is effective be suppressed while the possibility that the Vehicle is moving backwards from a stationary state, is safely suppressed, even on a slope, without there is a significant increase in costs.

In a preferred embodiment of the invention, the Clutch control unit be designed so that when the Brake switch is closed, or when the absolute value of the Vehicle speed greater than 0 (zero) km / h is during the current command value is gradually reduced, the Clutch control unit causes the current command value instantaneously to the value for effecting the creep control increases.

With the arrangement described above Control device for an electromagnetic clutch can the backward movement of one on a slope persistent motor vehicle suppressed to a minimum become.

The above as well as other tasks, features and accompanying Advantages of the present invention become better understandable by reading the following description of preferred versions, which serve only as examples, and by studying the accompanying drawings.

In the course of the following description, reference is made to the Drawings referenced in which:

Fig. 1 is a block diagram showing schematically the structure of a synchronized automatic transmission system, which is equipped with a control device for the electromagnetic clutch according to a first embodiment of the present invention;

Fig. 2 is a timing chart to illustrate the operation of the electromagnetic clutch control device according to the first embodiment of the invention;

Fig. 3 is a flow chart for illustrating the control mode discrimination or judgment processing, which is performed during the creep control according to the first embodiment of the invention; and

Fig. 4 is a flow diagram illustrating the Kriechsteuerungsverarbeitung, which is carried out in relevant control modes, respectively, according to the first embodiment of the invention.

The present invention will now be described in detail with reference to Descriptions described, which are currently preferred or typically viewed with reference to the Drawings. In the following description designate the same Reference signs the same or through several views corresponding parts.

Version 1

Now with reference to the drawings Control device for the electromagnetic clutch a synchronized automatic transmission system according to one first embodiment of the present invention.

FIG. 1 is a block diagram generally and schematically showing the structure of a synchronized automatic transmission system or an automated manual transmission equipped with a control device for an electromagnetic clutch according to a first embodiment of the invention. As can be seen from the figure, a synchronized multi-speed change gear unit (hereinafter also referred to as a multi-speed change gear unit), which is generally designated by the reference numeral 3 and is a main part of the synchronized automatic transmission system, is operative with a crankshaft (output shaft) 21 of an engine 1 , like an internal combustion engine, coupled or connected via the medium of an electromagnetic clutch 2 .

A control unit 4 , which is formed by a microcomputer or microprocessor which is designed or programmed to provide various arithmetic functions, is provided for controlling the operation of the engine 1 , the electromagnetic clutch 2 and the multi-stage gear change transmission unit 3 on the basis of sensor information , which can be derived from the output signals from various sensors, which indicate the operating state of the engine 1 .

A shift / selection actuator 5 serves to actuate the multi-stage gear change transmission unit 3 under control of the control unit 4 , while a shift / selection position sensor 6 serves to determine the actual shift / selection position VY; VX of the multi-speed gear change transmission unit 3 to thereby provide a signal which indicates to the control unit 4 the detected shift / selection position.

The multi-stage gear change transmission unit 3 is equipped with an input shaft 22 , with which a gear wheel 23 of the fourth gear, which serves as the primary gear wheel, is directly coupled. Sequentially after the fourth gear gear 23 , a third gear gear 24 , a second gear gear 25 , a first gear gear 26 , a fifth gear gear 27, and a reverse gear (also referred to as a reverse gear) 28 are each arranged.

Further, there are three gear bushings 29 between the fourth gear gear 23 and the third gear gear 24 , between the second gear gear 25 and the first gear gear 26 , and between the reverse gear 28 and the fifth gear gear 27, respectively arranged. Each of the gear bushings 28 is directly movably connected to an output shaft 30 of the multi-speed speed change gear unit 3 in the axial direction of the output shaft 30 .

Further, the individual gear transmission gears 23 constitute up to 28 each gear sets, along with gear wheels which are directly mounted on a counter shaft 31, which are arranged parallel to the output shaft 30, each of the transition gears 23 to 28 in permanent engagement with the mounted on the counter shaft 31 Gegengetrieberad is set.

With the arrangement described above, the output shaft 30 is operatively coupled to one of the individual gear wheels 23 to 28 by the gear bushing 29 , thereby being operatively coupled to the input shaft 22 .

As is apparent from the above, in the case of the synchronized automatic transmission system according to the present embodiment of the invention, the multi-speed gear change unit 3 is implemented in the form of a five-speed gear with speed change and counter shaft, which contains five forward speed gear sets that differ in gear ratio , a reverse gear set and three gearbox bushings for switching the gear engagement states.

An input speed sensor 7 is provided in association with the fourth speed gear 23 mounted on the input shaft 22 to detect the input speed Ni (RPM) of the multi-speed speed change gear unit 3 . In connection with the output shaft 30 , an output speed sensor 8 is provided, for detecting the output speed (rpm) of the multi-stage gear change transmission unit 3 as vehicle speed Vr.

A throttle valve 10 , which is designed to be actuated by a throttle valve actuator 11 , is set up within an intake pipe 9 of the engine 1 . Furthermore, a throttle position sensor 12 is provided in connection with the throttle valve 10 in order to detect the throttle position or the throttle opening degree θ.

Furthermore, in order to detect the actuation stroke of the accelerator pedal (not shown), which is designed to be actuated by the driver of the motor vehicle, an accelerator pedal position sensor 13 is provided, the output signal of the accelerator pedal position sensor 13 , which is proportional to the actuation stroke α of the Accelerator pedal indicates how it is operated by the driver, which is fed to the control unit 4 .

The control unit 4 is programmed or designed to process the output signal of the accelerator pedal position sensor 13 , thereby thereby arithmetically determining a desired or desired throttle valve opening degree θO, which corresponds to the accelerator pedal actuation stroke α, whereupon the control unit 4 controls the throttle valve 10 by means of the throttle valve Actuator 11 actuated via a feedback loop, based on the deviation or difference between the desired throttle opening degree θo and the detected throttle opening degree θ, so that the actual throttle opening degree θ as detected is with the desired one Throttle valve opening degree θo is matched (ie θ = θo).

Furthermore, the control unit 4 is input a gear lever position signal which indicates the gear position (eg parking area P, reverse area R, neutral area N or driving area or drive area D) of a selector lever 14 which is operated by the driver of the motor vehicle.

An engine speed sensor 15 is used to detect the engine speed Ne (rpm) of the engine 1 , and the output signal of this sensor 15 is supplied to the control unit 4 .

A reverse gear switch 16 is provided in association with the reverse gear 28 of the multi-speed change gear unit 3 to detect the operating status of the reverse gear 28 .

Furthermore, a brake switch 17 is provided, which is designed to output a signal that indicates a brake pedal operating state, ie the state in which the brake pedal (not shown) is depressed by the driver. The output signal of the brake switch 17 is also fed to the control unit.

The control unit 4 is designed or programmed so that it makes a decision about the gear change, thereby controlling the shift / selection actuator 5 depending on the result of the gear shift decision, whereby the gear stage in accordance with a shift pattern (shift diagram or shift profile) is determined based on the accelerator operating stroke α and the vehicle speed Vr. In this way, a plurality of gear stages of the multi-stage gear change transmission unit 3 can be shifted automatically from one to the other.

The basic operation of the synchronized automatic transmission system including the electromagnetic clutch control device according to the first embodiment of the invention shown in FIG. 1 will now be described in general.

The electromagnetic clutch 2 is actuated or electrically excited by a clutch excitation current, which has an amount corresponding to a clutch transmission torque (ie, the torque to be transmitted from the electromagnetic clutch 2 ), under the control of the control unit 4 , thereby causing the torque transmission (or its interruption) from the crankshaft (output shaft) 21 of the engine 1 to the input shaft 22 of the multi-speed change gear unit 3 .

In the multi-stage speed change gear unit 3 , the output torque of the engine 1 is transmitted to the countershaft 31 via the primary gear wheel attached to the input shaft 22 at its front portion. The output shaft 30 extends forward (to the left in the figure) beyond the third gear set. The transmission path of the torque, and the gear ratio of the multi-speed gear change unit (ie, product of the gear ratio of the primary gear multiplied by the gear ratio of the coupled gear gear) is determined depending on which of the gear gears 24 , 25 , 26 , 27 and 28 that are on the Output shaft 30 are attached, is operatively coupled.

At the fourth gear stage, input shaft 22 and output shaft 30 are operatively coupled straight. The gear change process of the multi-stage gear change transmission unit 3 is controlled by selective shifting or switching of the gearbox bushings 29 , by means of the shift / selection actuator 5 , which serves the gear changeover process.

In other words, the multi-stage speed change gear unit 3 performs a disengagement operation to release the mechanical engagement of the gear wheels of the currently valid gear stage and a coupling operation to engage the gear wheels at the subsequent gear stage under the shift control of FIG Gearbox bushings 29 , which is carried out by the switching / selection actuator 5 .

In this connection, the control unit 4 is designed or programmed such that an optimal gear stage is set by querying a shift pattern, based on the set position of the gear lever 14 , the actuation stroke α of the accelerator pedal, the engine speed (rpm) Ne and the vehicle speed Vr to thereby control the shift / selection actuator 5 accordingly while the shift / selection position is detected with the shift / selection position sensor 6 .

The synchronous state of the gearbox bushings 29 can be detected based on the relationship between the input speed (rpm) Ne and the output speed Vr, which are detected by the input speed sensor 7 and the output speed sensor 8 , respectively.

Further, the throttle valve opening degree θ is set to a predetermined opening value by the throttle valve actuator 11 , while the excitation current for the electromagnetic clutch 2 is set to zero under the control of the control unit 4 , whereby the multi-speed gear change gear unit 3 in FIGS so-called off state or de-energized state is set, in which the gear stage change (or gear change) process can be carried out.

Next, the operation of the synchronized automatic transmission including an electromagnetic clutch according to the first embodiment of the invention will be described more specifically with reference to a timing chart shown in FIG. 2.

In FIG. 2 it is assumed the motor vehicle that is in a state in which the motor vehicle is stopped by depressing the brake pedal on a slope, and the creep (English: creep control) has been validated made or valid.

In FIG. 2, the vehicle speed Vr takes in response to the closing, or "ON" of the brake switch 17 off. When the vehicle is stopped (ie, when Vr = 0 km / h), the brake pedal is released, with the brake switch 17 opened or turned "OFF".

After the vehicle has stopped, the controlled creep force is balanced with the downward force which acts on the motor vehicle due to the gradient of the slope. Thus, the stopping state of the motor vehicle is maintained even after the brake switch 17 has been opened (OFF).

When the brake switch 17 is opened (OFF) and the vehicle speed Vr becomes zero (0 km / h), the clutch control is started, whereby the clutch command current value ic (hereinafter simply referred to as the current command value ic) according to the state at that time is set.

The current command value ic is controlled to gradually decrease in accordance with a predetermined gradient (rate of change) when a decision period TA has elapsed since the start of the feedback control (creep control). In this connection, however, it should be mentioned that in the event that the absolute value of the vehicle speed Vr becomes greater than zero (0 km / h) or the brake switch 17 is closed (ON) before the current command value ic zero amperes (0 A) has reached, the current command value ic immediately assumes the current command value for the creep control which was validated before the gradual reduction of the current command value began.

In the state shown in FIG. 2, as an example, it is assumed that the vehicle speed Vr due to the backward movement of the motor vehicle by the downward force due to the gradient of gradient appears in the course of the gradual decrease of the current command value ic, from which it follows that the current command value ic precedes Beginning of the gradual reduction assumes the valid value again, and that the driver or operator has depressed the brake pedal again, whereby the brake switch 17 is closed or "ON".

In connection with FIG. 2, it should first be mentioned that among the control mode display flags or markings shown in FIG. 2, a creep reduction control flag FCD, a feedback start control flag FBR, and a creep control flag FC are used in ordinary creep control become. On the other hand, the present invention relates to a command current gradient control flag FCC and a feedback control flag FBB.

Each of the control flags mentioned above becomes exclusive set. In other words, only one flag is at a time set.

At the time when the feedback start control flag FBR is set, the current command value ic does not immediately increase from 0 (zero) amperes to the feedback current value (ie, creep control current value), but initially gradually increases to a preset or predetermined value ir , whereupon the current command value ic rises steeply to the creep control current value, as can be seen in FIG. 2.

Next, referring to the flowcharts shown in Figs. 3 and 4, the operation of the electromagnetic clutch control device of the synchronized automatic transmission according to the first embodiment of the present invention will be described in more detail.

Fig. 3 shows a processing routine for deciding the control mode status (control flag setting status) in the course of the creep control, and Fig. 4 shows processing routines which are executed in correspondence to the individual control flags during the actual creep control.

In FIG. 3, it is first decided in step S10 whether or not the brake switch 17 is in a closed state (ON state). If it is decided in step S10 that the brake switch 17 is closed (ie if the decision step S10 leads to an affirmative "YES"), then it is decided in the subsequent step S11 whether or not the vehicle speed Vr 0 (zero) km / h is. As for the processing after step S11, it will be described later.

Conversely, if it is decided in step S10 that the brake switch 17 is open or in the OFF state (ie, if the decision step S10 results in a negative answer "NO"), it is decided in step S12 whether or not the vehicle speed Vr 0 Is (zero) km / h.

If it is decided in step S12 that the vehicle speed Vr is not zero (Vr ≠ 0), that is, if the decision step S12 leads to "NO", the feedback start control flag FBR is set in a step S25, whereupon a timer counter TM in a step S26 is reset to zero. The processing routine shown in Fig. 3 then ends.

In that case, only the feedback start control flag FBR set while the other control flags (which described later) can be reset, as long as how one flag is set, the other set Control flags are suppressed as previously described.

On the other hand, if it is decided in step S12 that the vehicle speed Vr is zero (Vr = 0), that is, if the decision step S12 leads to "YES", the timer counter TM is incremented in a step S13, whereupon a decision is made in step S14 whether or not the value of the timer counter TM is greater than or equal to a predetermined value XTA which corresponds to the decision period TA (see FIG. 2).

If it is decided in step S14 that the value of the pointer counter TM is greater than or equal to the preset value XTA (TM ≥ XTA), that is, if the decision step S14 results in "YES", the creep control flag FC for the ordinary creep force decrease is Control is set in step S15, whereupon the processing routine shown in FIG. 3 ends.

Conversely, if it is decided in step S14 that the timer counter value TM is less than the preset value XTA (TM <XTA), that is, if the decision step S14 results in "NO", the processing routine shown in FIG. 3 becomes without executing the processing step S15 ended.

On the other hand, if it is decided in step S11 that the vehicle speed Vr is zero km / h (Vr = 0), that is, if the decision step S11 results in "YES", after the decision in step S10 that the brake switch 17 is closed or is ON (ie, "YES"), the creep control flag FCD is set and the timer counter TM is reset to zero in a step S16, whereupon the processing routine shown in FIG. 3 ends.

It is now assumed that a decision is made in step S11 that the vehicle speed Vr is not zero km / h (Vr ≠ 0), i.e. H. decision step S11 leads to "NO". In that case, the timer counter TM becomes in step S17 incremented, whereupon decisions are made in a step S18 becomes whether or not the current command value ic becomes larger or is equal to the predetermined value ir.

If it is decided in step S18 that the current value ic is smaller than the predetermined value ir (ic <ir), that is, if the decision step S18 results in "NO", the aforementioned feedback start control flag FBR is set in step S25 while the timer counter TM is reset to zero in step S26. Then the processing routine shown in Fig. 3 ends.

Conversely, if it is decided in step S18 that the Current command value ic greater than or equal to the predetermined value ir is (ic ≥ ir), i. H. if decision step S18 is too "YES" leads, it is then decided in step S19 whether or not not the value of the timer counter TM greater than or equal to that default value is XTA (corresponding to the Decision period TA).

If it is decided in step S19 that the value of the Timer counter TM greater than or equal to the preset XTA is (TH ≥ XTA), i.e. H. when the decision step S19 leads to "YES", the current current command value ic arithmetically determined by subtracting a predetermined one Value Δi (equivalent to a gradient decrement amount) of the previous current command value ic (feedback Current value), in a step S20.

At this point it should be noted that the processing routine shown in Fig. 3 is executed periodically, for example every ten seconds. As a result, the current command value ic is decremented every ten seconds by the predetermined value Δi.

It is then decided in step S21 whether or not the current current command value ic is greater than or equal to zero amperes (0 A). If it is decided in step S21 that the current current command value ic is less than zero amperes (ie, if the decision step S21 is "NO"), the aforementioned creep control control flag FCD is set in step S16, whereupon the processing routine shown in FIG. 3 ends.

Conversely, if it is decided in step S21 that the current current command value ic is greater than or equal to zero amperes (0 A) (ie, if decision step S21 results in "YES"), the current command gradient control flag FCC is set in step S22, whereupon the routine shown in Fig. 3 ends.

On the other hand, if it is decided in step S18 that the value of the timer counter TM is smaller than the preset value XTA (TM <XTA), that is, if the decision step S19 is negative with "NO", the feedback control flag FFB is set in step S23 while the timer counter TM is reset to zero in step S24. Then the processing routine shown in Fig. 3 ends.

After one of the control flags is set as described above with reference to FIG. 3, processing proceeds to a routine included in the creep control procedure shown in FIG. 4. In connection with FIG. 4, it should first be mentioned that the current command value ic is determined in each control mode depending on the set status of the control flag determined by the procedure shown in FIG. 3.

In Fig. 4, it is first decided in a step S100 whether or not the creep control control flag FCD is set to "1". If it is judged in step S100 that the creep control flag FCD is "1" (FCD = "1"), that is, if the decision step S100 results in "YES", the control for reducing the creep is executed in step S110, whereupon the processing routine shown in Fig. 4 ends.

On the other hand, if it is decided in step S100 that the Creep force reduction control flag FCD is "0" (FCD = "0"), i.e. H. if decision step S100 is "NO" a decision is made in a step S120 whether or not the creep control flag FC is not set to "1".

If it is decided in step S120 that the creep control flag FC is "1", that is, FC = "1"("YES" in step S120), the ordinary control (gradual decrease control) of the creep is performed in step S130, whereupon the processing routine shown in Fig. 4 ends.

On the other hand, if it is decided in step S120 that the Creep control flag FC is "0", i.e. H. FC = "0" ("NO" in step S120), then in step S140 decided whether or not to start the feedback Control flag FBR is set to "1".

If it is decided in step S140 that the feedback start control flag FBR is set to "1", that is, FBR = "1"("YES" in step S140), the feedback start control (that is, control for gradually increasing the creep force until that Current command value ic has reached the predetermined value ir) in step S150, whereupon the processing routine shown in FIG. 4 ends.

Further, if it is decided in step S140 that the Feedback start control flag FBR is "0", i. H. FBR = "0" ("NO" in decision step S140), then in a step S160 decided whether or not that Current command gradient control flag FCC is set to "1".

If it is decided in step S160 that the current command gradient control flag FCC is set to "1", that is, FCC = "1"("YES" in step S160), the gradual or gradient control of the current command value ic after the decision period TA expires becomes one Step S170 is executed, whereupon the processing routine shown in FIG. 4 ends.

On the other hand, if it is decided in step S160 that the current command gradient control flag FCC is set to "0", that is, FCC = "0"("NO" in step S160), it means that the feedback control flag FFB over which to decide remains set to "1". Accordingly, the ordinary feedback gradient control is performed in step S180, whereupon the processing routine shown in FIG. 4 is ended.

In this way, when the braking state (state in which the brake switch 17 is closed) is detected in the course of the crawling operation, the excitation current (current command value ic) of the electromagnetic clutch 2 is corrected based on the vehicle speed Vr so that the motor vehicle faces an abrupt or sudden movement is protected.

Further, by gradually decreasing the current command value ic with a gradient, the electromagnetic clutch 2 is prevented from being quickly disengaged, whereby a steep increase in the speed (rpm) of the motor 1 can be surely prevented.

Likewise, in the case where the state in which the gear lever 14 (range switch) is set to a position which is within the driving range D while the brake switch 17 is open and in which a vehicle speed Vr of 0 (zero) ) km / h is specified, for the decision period TA has lasted, the current command value ic for the electromagnetic clutch 2 is not immediately reduced to zero amps, but is gradually reduced. Thus, the creep control state (slightly clutched state) of the electromagnetic clutch 2 can be prevented from continuing for a long time when the motor vehicle is stopped, while avoiding a steep decrease in the creep drive power of the multi-speed speed change gear unit 3 .

In this context, it should also be noted that if the Current command value ic in the state in which the vehicle is on on an incline, gradually decreasing, one Backward movement of the motor vehicle when it occurs only can start gently. So the driver has enough time to notice the backward movement of the motor vehicle, and to brake the motor vehicle, making safety is improved.

Likewise, if the brake switch 17 is closed in the course of the gradual decrease in the current command value ic, or if the absolute value of the vehicle speed Vr becomes greater than 0 (zero) km / h, then the current command value ic instantaneously changes from zero amps to the current command value (ic) raised, which is required for the creep process. Thus, the backward movement of the motor vehicle on an incline can be suppressed to a minimum.

Many modifications and variations of the present Invention is possible in light of the above techniques. you should therefore understand that the invention within the The scope of the appended claims is also different as described in detail here.

Claims (2)

1. Device for controlling an electromagnetic clutch of a synchronized automatic transmission system, which is designed to automatically change a plurality of gear stages in a synchronized multi-stage gear change transmission unit installed in a motor vehicle, comprising:
a brake switch ( 17 ) for detecting a state in which a brake pedal is depressed;
a range switch ( 14 ) for detecting gear positions including a driving range (D);
an accelerator pedal position sensor ( 13 ) for detecting the operating stroke of an accelerator pedal;
a vehicle speed sensor ( 8 ) for detecting the output speed of the synchronized multi-speed gear change unit ( 3 ) as the vehicle speed of the motor vehicle; and
a control device ( 4 ) for changing the gear stages of the multi-stage gear change transmission unit ( 3 ) on the basis of detection signals of the brake switch ( 17 ), the range switch, the accelerator pedal position sensor and the vehicle speed sensor ( 8 ),
wherein the multi-stage gear change transmission unit ( 3 ) includes an electromagnetic clutch ( 2 ) for performing transmission / interruption of the drive power at the beginning and end of the change of the gear stages, and creep control;
wherein the control device ( 4 ) includes a clutch control unit for supplying an excitation current to the electromagnetic clutch ( 2 ); and
wherein the clutch control unit is configured so that a current command value (ic) for the excitation current gradually decreases from a value for executing the creep control to zero amperes in the case where a state in which the gear position is within the driving range (D), while the brake switch ( 17 ) is open (OFF) and in which the vehicle speed (Vr) is indicated as 0 (zero) km / h has lasted for a predetermined period. 2. Control device for an electromagnetic clutch for a synchronized automatic transmission according to claim 1, characterized in that if in the course of the gradual reduction in the current command value (ic) the brake switch ( 17 ) is closed or the absolute value of the vehicle speed (Vr) becomes greater than zero, the clutch control unit instantaneously causes the current command value (ic) to increase to the value for effecting the creep control.