JP2853410B2 - Control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission in which selection of a plurality of travel ranges is realized by electric control.

[0002]

2. Description of the Related Art In an automatic transmission, a drive range, a reverse range or a neutral range is switched by a range switching valve (manual valve).
This is performed by switching. Although the range switching valve is generally switched by manual operation, an automatic transmission having a configuration in which the switching is performed by electrical control has already been proposed.

[0003] The applicant of the present invention also discloses, for example, Japanese Patent Application No. 3-1.
A control device for an automatic transmission is proposed as shown in the specification and the drawings attached to the application No. 8248. This device is configured to switch a range switching valve of an automatic transmission by an actuator that is electrically driven and controlled. And when this actuator fails,
Neutral control means is provided for interrupting control oil pressure to a friction engagement device for setting each traveling range of the automatic transmission and forcibly bringing the automatic transmission into a neutral state. Moreover, when the neutral control means detects a failure,
The engine is stopped by fuel cut.

[0004]

When both the actuator and the neutral control means fail in the control device, the actuator fails in the drive (D) range, and the running state of the vehicle exceeds a predetermined speed. The engine is stopped even while the vehicle is traveling forward. This is not preferable because the brake operation or the power steering operation after stopping the engine becomes heavy, giving the driver an uncomfortable feeling. The D range is a forward range including a third speed range, a second speed range, and a low range.

Stopping the engine immediately due to the failure of the actuator and the neutral control means during forward running of the vehicle is not necessarily excellent in terms of safety measures. In particular, during high-speed running, the engine is driven. It is safer to continue. However, at the time of the failure, when the vehicle is running at a low speed or stopped, for example, and the driver intentionally selects a parking (P) range, a reverse (R) range, or a neutral (N) range other than the D range. Since the driver intends to stop the forward running, in this case, it is preferable to stop the engine in terms of safety measures.

The technical problem of the present invention is that when the actuator fails, the range position of the actuator is the D range, the driver's instruction range is other than the D range, and the vehicle is traveling forward at a predetermined speed or less (including stopping). ) Or the engine is stopped only when the vehicle is in the reverse running state, and the engine is not stopped under other conditions, thereby further improving the safety at the time of actuator failure.

[0007]

In order to solve the above-mentioned problems, a control device for an automatic transmission according to the present invention is configured as follows. That is, an actuator for switching and driving the range switching valve of the automatic transmission and an electric signal of an instruction range based on the operation of the range selection switch, and a driving signal corresponding to this signal is output to electrically drive the actuator. A control unit for an automatic transmission, wherein a signal for stopping the engine is output from the range control unit when a failure of the actuator is determined by the range control unit. And a valve position sensor for detecting the range position of the range switching valve and outputting the detection signal to the range control unit, and a travel of the vehicle. A vehicle speed sensor that detects a speed and outputs a detection signal to the range control unit, In Nji controller when the actuator is determined to fail,
The range position of the actuator based on the detection signal of the actuator position sensor is a drive range, the indicated range is other than the drive range, and the traveling state of the vehicle based on the detection signals of the vehicle speed sensor and the valve position sensor is lower than a predetermined speed. A signal for stopping the engine is output only when the vehicle is in the traveling state or the backward traveling state.

[0008]

According to this configuration, when the range control section determines that the actuator has failed, the following condition (1) is obtained based on the detection signals output from the sensors to the range control section. A signal for stopping the engine is output from the range control unit only when the conditions (3) to (3) are satisfied.

(1) The range position of the actuator is in the D range. (2) The driver's instruction range is other than the D range. (3) The traveling state of the vehicle is low-speed forward traveling (including stopping) or backward traveling.

Therefore, when all of the above conditions (1) to (3) are satisfied, that is, when the actuator fails, the running state of the vehicle is low-speed running, stopped or backward running, and the driver is in the D range. The engine stop is executed only when the P range, the R range, or the N range other than is selected. Even if the conditions (1) and (2) are satisfied, a signal for stopping the engine is not transmitted if the running state of the vehicle is high-speed forward running. In this case, for example, the range switching is performed. Actions such as stopping control are executed.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a perspective view showing an outline of a range switching valve 30 for switching a traveling range of an automatic transmission and a driving system thereof. The range switching valve 30 is of a spool valve type, and is supplied with a line hydraulic pressure serving as a basic hydraulic pressure for controlling the automatic transmission. By operating the spool of the range switching valve 30 in the axial direction, the discharge port thereof is switched, and engagement and release of a friction engagement device (not shown) for setting each traveling range is controlled.

A detent lever 36 is fixed on the control shaft 32 shown in FIG. The detent lever 36 rotates in conjunction with the rotation of the control shaft 32 about the axis thereof, whereby the range switching valve 3
It is configured to move the zero spool in its axial direction.

The detent lever 36 has a fan shape, and a plurality of uneven portions 36a are formed on the outer periphery thereof. For one of these concave and convex portions 36a,
Roller 3 provided at end of detent spring 38
8a are selectively engaged. These members constitute a detent mechanism 34 for positioning the rotational position of the control shaft 32, that is, a plurality of range positions of the range switching valve 30.

In order to switch the range switching valve 30,
A DC motor is used as the actuator 50 that is electrically driven and controlled. This actuator 5
The worm 54 formed on the drive shaft 52 is provided with a worm wheel 5 fixed on the axis of the control shaft 32.
6 is engaged. Thus, the rotation of the drive shaft 52 of the actuator 50 is reduced and transmitted to the control shaft 32 by the engagement between the worm 54 and the worm wheel 56.

FIG. 1 shows a system diagram of the electric control.
In this drawing, a range selection switch 10 is a position switch that is switched in response to an operation of a select lever by a driver to select a travel range of the automatic transmission AT, or an operation switch that is directly operated by the driver.

In FIG. 1, range control unit 20 (SBW control unit) uses a microcomputer, and is a read-only memory (ROM) storing programs necessary for various software processes for switching the running range of automatic transmission AT. And a central processing unit (CPU) for executing the program, a writable memory (RAM) for temporarily storing variables required for the program, and the like.

A microcomputer is also used for the automatic transmission control unit (ECT control unit) 22 and the engine control unit (EFI control unit) 24 shown in FIG.
The automatic transmission control unit 22 includes an automatic transmission AT
Is automatically controlled based on the vehicle speed and the engine load, and the engine control unit 24 controls the fuel injection amount from the fuel injection valve (EFI) based on the rotation speed of the engine EG and the intake air amount. I do.

Further, FIG. 1 shows an actuator position sensor 40 for detecting the range position (drive amount) of the actuator 50 on the side of the automatic transmission AT, and a range position (spool operation amount) of the range switching valve 30. A valve position sensor 42 and a vehicle speed sensor 44 for detecting the traveling speed of the vehicle are shown.

An instruction range signal a output by operating the range selection switch 10 and respective detection signals b output from the actuator position sensor 40, the valve position sensor 42 and the vehicle speed sensor 44 are provided to the range control unit 20. , C, d are input together. In addition, a drive signal e corresponding to the range signal a is output from the range control unit 20.
Is output to the drive circuit 58 of the actuator 50. In addition, when the range control unit 20 determines that the actuator 50 has failed, the range control unit 20 sends request signals f and g for fail processing to the automatic transmission control unit 22 and the engine control unit 24, respectively. Is output.

The automatic transmission control unit 22 transmits the request signal f
Based on the above, even if the range indicated by the operation of the range selection switch 10 is the R range, this signal is canceled and the range is forcibly changed to the N range (R prohibition signal), or depending on the condition, the range switching control is stopped. The signal is output to the automatic transmission AT. On the other hand, the engine control unit 24
Outputs an engine stop signal such as fuel cut to the engine EG based on the request signal g.

In addition, R prohibition for the automatic transmission AT,
The signals for stopping the range switching control and the signal for stopping the engine for the engine EG are output under the conditions shown in Table 1 below.

[0023]

[Table 1]

Among the various codes used in Table 1 above, codes other than the range (P, R, N) have the following meanings. D: Forward range including 3 range, 2 range and L range. -; Any state is acceptable. S: Vehicle stopped. DH: Forward running with V> V0. DL: forward running with V ≦ V0. CS; control stopped. ES: Engine stopped.

As the means for judging the failure of the actuator 50 in the range control section 20, for example, one of the following two means may be employed. (A) The drive current of the actuator 50 is monitored, and it is determined that a failure has occurred when an excessive current has flowed for a predetermined time or more. (B) When it is recognized that the actuator 50 is not driven based on the detection signal b from the actuator position sensor 40 even though the drive signal e for controlling the drive of the actuator 50 is output. Is determined as failed.

FIG. 3 is a flowchart showing the contents of software processing in the range control section 20.
In step S1 of this drawing, the actuator 50 is determined by one of the fail determination means (a) and (b).
It is determined whether or not failed. If the determination result is yes, the process proceeds to step S2. If the determination result is no, the process of the present embodiment ends and the process proceeds to the next process. In step S2, based on the detection signal b from the actuator position sensor 40, it is determined whether or not the range position determined after the actuator 50 has failed is the R range. If the determination result is yes, the process proceeds to step S3, and if the result is no, the process proceeds to step S7.

In step S3, it is determined whether or not the indicated range is the R range based on the signal a by the operation of the range selection switch 10. If the answer is no,
In step S4, the automatic transmission AT is forcibly set to N.
The automatic shift control unit 22 outputs an R prohibition signal for setting the range.

On the other hand, if the decision result in the step S3 is YES, the process proceeds to a step S5, where it is determined whether or not the vehicle is traveling forward based on the detection signal c from the valve position sensor 42. If the result of this determination is yes, it is further determined in step S6 whether or not the vehicle speed V determined by the detection signal d from the vehicle speed sensor 44 is greater than a predetermined speed value V0.

That is, in steps S5 and S6, the running state of the vehicle is determined, and the vehicle is moved to a predetermined speed value V0.
If the vehicle is traveling at a higher speed than the above, the result of the determination in step S6 is YES, and the process proceeds to step S4. In this step S4, even if the indicated range is the R range, this is canceled and, as described above, the automatic transmission A
The automatic shift control unit 22 outputs an R prohibition signal for forcibly setting T to the N range. Steps S5 and S
In the case where each of the determination results in No. 6 is NO, in step S13, the automatic transmission control unit 22 outputs a signal for stopping the control of range switching of the automatic transmission AT.

If it is determined NO in step S2 and the process proceeds to step S7, it is determined in step S7 whether the range position determined after the actuator 50 has failed is the D range. If the result of this determination is yes, the process proceeds to step S8, and if no, the process proceeds to step S13, in which a signal for stopping the control of range switching is output from the automatic transmission control unit 22 in the same manner as described above.

In step S8, it is determined whether or not the designated range is the D range. If the result of the determination is yes, the process proceeds to step S13 to execute the same processing as described above, and if the result of the determination is no, the process proceeds to step S9.
In step S9, it is determined whether the vehicle is traveling forward. If the result of this determination is NO, an engine stop signal such as fuel cut is output from the engine control unit 24 in step 10.

If the result of the determination in step S9 is YES, the flow advances to step S11 to determine whether or not the vehicle speed V is greater than a predetermined speed value V0. If the result of this determination is no, the engine stop signal is output from the engine control unit 24 in step 10 described above, and if yes, the instruction range (range other than the D range) of the range selection switch 10 is changed to the D range in step S12. After issuing the return warning, the automatic shift control unit 22 outputs a signal for stopping the control of the range switching in the step S13.

According to the above processing, control of R prohibition for the automatic transmission AT, stop of range switching control, and control of engine stop for the engine EG are executed in accordance with the conditions shown in Table 1 above.

Embodiment 2 In the control system shown in FIG. 4, an electric signal from a detector 70 for detecting the drive current of the actuator 50 is input to the range control unit 20. That is, in the present embodiment, a means for monitoring the drive current of the actuator 50 is employed as the previously described fail determination means.

In FIG. 4, a running range indicator 60 is provided on an instrument panel located in front of the driver. When the range control unit 20 determines that the actuator 50 has failed, a signal h is output from the range control unit 20 to the indicator 60,
For example, the current running range is blinked on the indicator 60. In parallel with this, the range control unit 20
By outputting a signal i to the voice navigation control section 62 from the speaker 64, a sound warning of a failure may be output from the speaker 64.

FIG. 5 shows a change in the drive current I of the actuator 50 with respect to the time T at the time of range switching.
As is clear from this drawing, a large current flows when the actuator 50 is started. When the actuator 50 is locked or short-circuited electrically, an excessive current continues to flow. Therefore, the characteristic A of the solid line
When the time t during which the drive current I exceeds the predetermined current value I0 is smaller than the time T0 as shown by the following equation, it is assumed that the time t is longer than the time T0 as shown by the dotted line characteristic B. If the time is greatly smaller than the time T1, the actuator 50 and its electric system are regarded as abnormal, and the characteristic C indicated by a dashed line
The case where the time t is equal to or longer than the time T1 as described above is regarded as a failure of the actuator 50.

As described above, the drive current I of the actuator 50 is monitored, and the control is limited or stopped immediately when the current characteristics B and C shown in FIG. 5 are detected. Is avoided, or the fuse is blown. In addition to this processing, the driver 60 can be alerted to an abnormality or a failure of the actuator 50 by blinking of the indicator 60 or sound from the speaker 64, thereby prompting the driver to take prompt action.

In FIG. 4, members that are considered to be the same as or equivalent to those in FIG. 1 of the first embodiment are given the same reference numerals in the drawings, and duplicate descriptions are omitted.

[0039]

As described above, according to the present invention, when the actuator fails, the running state of the vehicle is in a low-speed running state, a stopped state or a backward running state, and the driver has a P range, an R range, or an N range other than the D range. By executing the engine stop only when the range is selected, for example, it is possible to avoid a situation in which the brake operation or the power steering operation becomes heavy due to the stop of the engine during high-speed running and gives a sense of incongruity to the driver. Safety at the time can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a control system in a control device according to a first embodiment.

FIG. 2 is a perspective view showing a range switching valve of the automatic transmission and a drive system thereof.

FIG. 3 is a flowchart showing the contents of a process in a range control unit.

FIG. 4 is a schematic diagram illustrating a control system in a control device according to a second embodiment.

FIG. 5 is a characteristic diagram showing a change in drive current of an actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Range selection switch 20 Range control part 30 Range switching valve 40 Actuator position sensor 42 Valve position sensor 44 Vehicle speed sensor 50 Actuator

Continuation of the front page (51) Int.Cl. ⁶ identification code FI F16H 59:74 (58) Investigated field (Int.Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61 / 24 F16H 63/40-63/48

Claims (1)

(57) [Claims] An actuator for switching a range switching valve of an automatic transmission and an electric signal of an instruction range based on an operation of a range selection switch, and outputting a drive signal corresponding to the signal to electrically connect the actuator to the actuator. A control device for an automatic transmission in which a signal for stopping the engine is output from the range control unit when a failure of the actuator is determined by the range control unit. An actuator position sensor that detects a range position of the actuator and outputs a detection signal to the range control unit, and a valve position sensor that detects a range position of the range switching valve and outputs the detection signal to the range control unit And a vehicle speed sensor that detects a traveling speed of the vehicle and outputs a detection signal to the range control unit. The range control unit is configured such that, when the actuator is determined to have failed, the range position of the actuator based on the detection signal of the actuator position sensor is a drive range, and the indicated range is other than the drive range, and the vehicle speed sensor and the valve position sensor. Whether the traveling state of the vehicle based on the respective detection signals is a forward traveling state at a predetermined speed or less,
Alternatively, a control device for an automatic transmission configured to output a signal for stopping the engine only when the vehicle is in a reverse running state.