JP3336957B2 - Transmission control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a shift control device for a continuously variable transmission employed in a vehicle or the like.

[0002]

2. Description of the Related Art Continuously variable transmissions used in vehicles include:
Conventionally, there are a belt type, a toroidal type and the like, and in a shift control device of these continuously variable transmissions, a controller constituted by a microcomputer or the like operates an actuator so that a target speed ratio calculated based on an operating state such as a vehicle speed is obtained. Is driven to control a hydraulic mechanism such as a speed change control valve so that the actual speed ratio matches the target speed ratio.

[0003] In such a shift control device, it is known that the controller is reset every time the power is turned on and starts a predetermined initialization (for example, Japanese Patent Application Laid-Open No. 7-310811). As disclosed in the official gazette, when the power is turned on, for example, when the ignition key is turned on while the vehicle is stopped, the actuator is set so that the speed ratio of the continuously variable transmission becomes a predetermined value on the large side (hereinafter referred to as Lo side). It is known that a shift control valve is driven through the control unit. When starting, the shift control valve is always controlled from the Lo side speed ratio.

[0004] The reset of the controller does not occur only when the vehicle is stopped, but also when the voltage is momentarily interrupted or dropped while the vehicle is running, the controller is reset. In order to prevent the initialization of the V-belt type continuously variable transmission from being started, when the controller is reset during traveling, instead of the initialization operation while the vehicle is stopped, the applicant changes the actual transmission speed. We proposed to set the drive position of the actuator again from the ratio and restart the shift control.

[0005]

However, in the latter conventional example, when a toroidal type is employed in the continuously variable transmission, a torque shift in which the gear ratio fluctuates in accordance with a change in input torque occurs. Therefore, the actual gear ratio is not always equal to the target gear ratio, and when the drive position of the actuator is obtained from the actual gear ratio as in the latter conventional example, the drive position of the actuator and the actual gear ratio are calculated. In some cases, the shift control is restarted in a state where the relationship is shifted, and the subsequent shift control cannot be performed accurately.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and when the controller is reset during traveling, the shift between the actual gear ratio and the drive position of the actuator is suppressed, so that gear shift control can be accurately performed. The purpose is to continue.

[0007]

[0008]

According to a first aspect of the present invention, there is provided a continuously variable transmission in which a gear ratio can be continuously changed by an actuator, the gear ratio is calculated, and the actuator is driven based on the gear ratio. Control means, first initialization means for initializing the actuator when the control means is reset while the vehicle is stopped, and when the control means is reset while the vehicle is running. And a second initialization means for continuously driving the actuator, the second initialization means comprising: means for calculating an actual gear ratio; A non-volatile storage means for storing the drive position of the motor at every predetermined control cycle; after the reset, an actual speed ratio stored in the non-volatile storage means and a deviation of the actual speed ratio calculated after the reset. And a deviation calculating means for calculating the absolute value of the deviation. When the absolute value of the deviation is equal to or less than a predetermined value, the driving of the actuator is restarted from the driving position of the actuator stored in the non-volatile storage means. Exceeds the predetermined value, the driving of the actuator is restarted from the driving position of the actuator estimated based on the actual gear ratio calculated after the reset.

[0009] The second invention is directed to the first invention.
There are, said second initialization means, until actual gear ratio is calculated after reset, it prohibits driving of the actuator.

[0010] The third invention is directed to the first invention.
There are, said second initialization means includes a means for determining an abnormality of the nonvolatile memory means, when it is determined that there is an abnormality in the nonvolatile storage means, based on the actual gear ratio, which is calculated after a reset Drive of the actuator is restarted from the drive position of the actuator estimated by the above.

[0011]

[0012]

Accordingly, the first aspect of the present invention relates to the case where the speed change control means is reset during traveling due to an instantaneous interruption of power or the like, and the actual speed ratio immediately before the reset stored in the non-volatile storage means and the value after the reset. When the absolute value of the deviation of the actual gear ratio exceeds a predetermined value, the actual gear ratio and the step motor drive position are estimated by estimating the step motor drive position from the actual gear ratio immediately after reset, as in the conventional example. Is not largely shifted, and the shift control can be continued following the change of the gear ratio during the reset.

According to a second aspect of the present invention, the drive of the actuator is inhibited until the actual gear ratio is calculated after the reset, so that the step motor drive position is accurately set after the reset during running. , The speed change control that has been interrupted can be restarted with higher accuracy.

According to a third aspect of the present invention, when it is determined that there is an abnormality in the nonvolatile storage means, the driving of the actuator is restarted from the driving position of the actuator estimated based on the actual gear ratio calculated after the reset. By doing so, although the control accuracy is reduced, fail-safe can be ensured by continuing the shift control.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show an example of a shift control device in the case of employing a toroidal type as a continuously variable transmission. The continuously variable transmission 2 has an engine 3 via a torque converter T / C. Are connected, and a step motor 4 as an actuator responsive to a command value of the shift control controller 1
However, the speed ratio of the continuously variable transmission 2 is continuously controlled via a speed change control valve 60 constituting a hydraulic control device.

As shown in FIG. 2, the transmission mechanism and the hydraulic control device of the continuously variable transmission 2
And a hydraulic cylinder 50 that axially drives a trunnion shaft 50a that supports the trunnion shaft 50a.
A feedback link 67 for feeding back the actual gear ratio to the shift control valve 60 and a precess cam 68 are provided.
6 that is relatively displaceable with the spool 63 that is driven
4.

The step motor 4 drives the spool 63 in response to a command from the transmission control controller 1,
By supplying and discharging hydraulic pressure to upper and lower oil chambers 50H and 50L defined by a piston 50P of the hydraulic cylinder 50, the trunnion shaft 50a is driven in the axial direction to tilt the power roller 5 (rotation around the trunnion shaft 50a). On the other hand, the tilt angle, that is, the actual gear ratio is fed back to the sleeve 64 that moves relative to the spool 63 via the precess cam 68 and the feedback link 67, and the oil pressure to the hydraulic cylinder 50 is changed to the target gear ratio RRTO. Position of the step motor 4 (the number of steps) according to the
, That is, the actual gear ratio RTO, and this gear ratio is uniquely determined according to the drive amount of the step motor 4.

Here, the step motor 4 and the speed change control valve 60 are connected by a rack formed on the spool 63 and a pinion provided on the step motor 4 meshing with each other. , Hi side) to a higher gear ratio (hereinafter referred to as Lo side),
The position where the end 63 a of the spool 63 is detected by the origin switch 12 constituted by a limit switch or the like is set to be the origin position of the step motor 4. The origin position is set to a position that is driven from the minimum drive position of the step motor to the Hi side by a predetermined amount.

The shift control controller 1 reads a throttle opening TVO (or accelerator pedal depression amount ACS) in response to a driver's operation of an accelerator pedal (not shown) from a throttle opening sensor 30 and a continuously variable transmission 2. Input shaft rotation speed N detected by the input shaft rotation sensor 11 of FIG.
t and the output shaft rotation speed N detected by the output shaft rotation sensor 13
o, respectively, to obtain a target input shaft rotation speed RREV according to the driving state from a shift map set in advance,
Driving position Ast corresponding to the target gear ratio to the step motor 4
ep (the number of steps) is commanded, and at the time of a normal reset in which the power is turned on while the vehicle is stopped, initialization is performed at the time of starting according to the output of the origin switch 12, while the power is reset during a run due to an instantaneous interruption of the power. In this case, the drive position Astep is reset in order to continue the shift control.

The transmission control controller 1 includes:
As will be described later, a backup memory 10 composed of a non-volatile memory is provided for storing data during traveling. The backup memory 10 has an EEPR
It is composed of an OM (Electrically Erasable Programmable ROM), a battery-backed RAM, and the like.

Next, an example of the shift control performed by the shift controller 1 will be described in detail with reference to the flowcharts of FIGS.

FIG. 3 shows a main routine of the shift control executed in the background processing, and FIGS. 4 to 7 each show a subroutine of the step motor driving processing.

In the main routine of FIG. 3, when the power is turned on, the initialization processing of steps S1 to S3 is performed, and then the processing of steps S4 to S9 is repeatedly executed in the background.

In step S1, the microcomputer and the I / O are initialized, and in step S2, it is checked whether or not the ROM (not shown) or the backup memory 10 is abnormal. The error flag Ferr is set to 1 while the error flag Ferr is reset to 0 when there is no abnormality.
The abnormality of the backup memory 10 can be detected by, for example, writing a predetermined value at a predetermined address and maintaining the predetermined value after reset.

Next, in step S3, various flags and variables used for control are initialized, and the initialization of the transmission control controller 1 is completed.

Next, in the shift control after step S4,
First, in step S4, signals from various sensors such as the throttle opening sensor 30 and switches are read.

Then, in step S5, the step motor driving process shown in FIG. 4 and subsequent steps is performed.
The output shaft rotation number No detected by the output shaft rotation sensor 13
Is multiplied by a predetermined constant to calculate the vehicle speed VSP.

In step S7, the input shaft speed Nt or the engine speed Ne is calculated, and the actual speed ratio RTO is calculated from the ratio of the output shaft speed No to the input shaft speed Ne. Backup memory 10
To be stored.

In step S8, a target gear ratio RRTO is calculated according to the driving state based on the input signal in step S4 and the vehicle speed VSP obtained in step S6.
In step S9, the drive position Astep (the number of steps) and the target drive position DsrSTP (the number of steps) of the step motor 4 according to the target speed ratio RRTO and the actual speed ratio RTO.
After calculating and storing the driving position Astep together with the actual gear ratio RTO in the backup memory 10, the driving position Astep is output by a step motor driving process described later. The step motor drive position Astep is set according to the response speed of the step motor 4, the oil temperature of the continuously variable transmission 2, and the like, and is a value for reaching the target drive position DsrSTP.

Next, the driving process of the step motor 4 will be described in detail with reference to the flowcharts of FIG.

First, in the flowchart of FIG. 4, it is determined whether or not the initialization has been completed in step S11 based on an initialization end flag Fend described later. If Fend = 0, the initialization has been completed. To step S12, while Fend =
If it is 1, it is determined that the initialization has been completed, and the process proceeds to step S19 to output the drive position Astep as described later.

In step S12 and subsequent steps when the initialization has not been completed, it is determined whether the reset of the shift control controller 1 that caused the initialization is a reset at the time of starting or a reset during running, based on the driving state of the vehicle. If it is determined that it is reset at the time of starting, step S
While the normal initialization is performed in step S16, if the reset is performed during running, the process proceeds to step S17 to perform the high vehicle speed initialization.

In steps S12 and S13, after the vehicle speed VSP and the input shaft speed Nt have been calculated in steps S6 and S7, the vehicle speed VSP is higher than a predetermined value V1 or the input shaft speed Nt is higher than a predetermined value N1. If the vehicle speed VSP is less than the predetermined value V1 and the input shaft rotation speed Nt is less than the predetermined value N1, the vehicle is reset during stopping, that is,
It is determined that the engine has started, and the process proceeds to the normal initialization in step S16.

On the other hand, in steps S12 and S13, if the calculation of the vehicle speed VSP and the input shaft speed Nt has not been completed in steps S6 and S7, the process proceeds to step S18, where the step motor drive position Astep and the target drive Position D
By setting both srSTP to 0, it is possible to avoid driving of the step motor 4 in the output processing of step S19,
After the calculation is completed, normal or high vehicle speed initialization is performed.

Next, the normal initialization performed in step S16 will be described in detail with reference to the flowchart of FIG.

In the normal initialization, the end portion 63a of the spool 63 driven by the step motor 4 in FIG.
Is to return to the origin position detected by the origin switch 12, and when the end 63a is beyond the origin switch 12 and is on the right side (Lo side) in the figure, the spool 63 is shifted to the Hi side in the figure. The point where the origin switch 12 is turned from ON to OFF by driving to the left is defined as the origin position LowSTP. On the other hand, when the end portion 63a is located on the left side (Hi side) in the drawing before the origin switch 12, the spool 63 To the right side in the figure where the gear ratio is Lo side, and the origin switch 1
2 is changed from OFF to ON to the origin position LowSTP
(See FIG. 8). The relationship between the gear ratio and the drive position of the step motor is set as shown in FIG.

First, in step S21, if the initialization flag Fi is set to 1 and it is not during initialization,
Initialization is performed in steps S22 to S27, and
After step 28, the step motor 4 is driven.

In the initialization processing, first, the initialization flag Fi is set to 1 in step S22, and then the origin switch 12 is turned off in step S23 as described above.
N and OFF are determined. If ON, the upshift flag is set to 1 in step S24 to drive to the Hi side as described above, and then the current drive position Astep is set to the minimum drive position in step S25. Assuming that Min = 0 and the target drive position DsrSTP is the maximum drive position Max (most Hi side), the process proceeds from step S28 to S29, and the step motor 4 is set to Hi until the origin switch 12 is turned off.
Drive to the side.

On the other hand, if the origin switch 12 is OFF, it is driven to the Lo side as described above.
After the downshift flag is set to 1 at 26, the current drive position Astep is changed to the maximum drive position Ma at step S27.
x (highest Hi side), and assuming that the target drive position DsrSTP is the minimum drive position Min = 0, steps S28 to S30
The step motor 4 is driven to the Hi side until the origin switch 12 is turned on.

When the origin switch 12 changes from ON to OFF or vice versa in steps S29 and S30, it is determined in steps S31 and S32 that the origin position has reached Low STP, and the initialization end flag Fend is determined.
Is set to 1, the drive position Astep and the target drive position DsrSTP are set to Low STP, and the initialization is terminated.

Next, the high vehicle speed initialization processing performed in step S17 of FIG. 4 will be described in detail with reference to the flowchart of FIG.

First, in step S41, the above-mentioned step S41 is executed.
It is determined in step S7 whether the calculation of the actual gear ratio RTO has been completed. If the actual gear ratio RTO has been calculated, step S4
2 and confirms that there is no abnormality in the backup memory 10 by using the error flag Ferr set in step S2.
Is determined based on whether or not is 0.

If there is no abnormality in the backup memory 10, the process proceeds to step S43, where the backup memory 1
0, the actual gear ratio RTO (RA
M) and the absolute value | ΔRTO | of the deviation of the actual speed ratio RTO obtained in step S7 as | ΔRTO | = | RTO−RTO (RAM) |.

In step S44, it is determined whether the absolute value | ΔRTO | of the deviation of the actual gear ratio is equal to or smaller than a predetermined value R1. If the absolute value | ΔRTO | is equal to or smaller than the predetermined value R1, the deviation is within an allowable range. Proceed to step S9
The step motor drive position Astep immediately before reset stored in the backup memory 10 together with the actual gear ratio RTO.
(RAM) is set as the current drive position Astep, the initialization end flag Fend is set to 1 in step S48, and the high vehicle speed initialization is ended.

If the absolute value | ΔRTO | of the deviation of the actual gear ratio exceeds the predetermined value R1 in step S44, or if there is an abnormality in the backup memory 10 as determined in step S42, the process proceeds to step S46. As shown in FIG. 8, a step motor drive position Astep is estimated from a map or a function of the drive position Astep and the actual gear ratio RTO set in advance, based on the actual gear ratio RTO obtained in step S7, by back calculation.

Then, similarly to the above, the initialization end flag Fend is set to 1 in step S48, and the high vehicle speed initialization is ended.

If it is determined in step S41 that the calculation of the actual gear ratio RTO has not been completed, the process proceeds to step S47, in which the driving position Astep and the target driving position Ds are determined.
Setting both rSTP to 0, holding the current position and waiting until the calculation is completed, step S45 or S46
On the other hand, the drive position Ast according to the actual gear ratio RTO
Set ep.

The output processing performed in step S19 is performed in step S19 as shown in the flowchart of FIG.
In steps S51 and S54, the magnitude of the target drive position DsrSTP is compared with the magnitude of the drive position Astep to determine the upshift or downshift shift direction. In steps S52 and S55, the drive position Astep is incremented by a predetermined amount (for example, one step). After the increase or decrease, the step motor 4 is driven in step S53.

Then, the above processing is repeated until the driving position Astep coincides with the target driving position DsrSTP.
The step motor 4 drives the transmission control valve 60 to tilt the power roller 5.

As described above, each time the shift controller 1 is reset, the normal initialization or the high vehicle speed initialization is performed as described above, and the vehicle speed VSP and the input shaft speed Nt are less than the predetermined values V1 and N1, respectively. At the time of middle or low vehicle speed, the step motor 4 returns to the origin position Low STP as shown in FIG.

On the other hand, when the vehicle speed VSP and the input shaft rotation speed Nt are running at high vehicle speeds equal to or higher than the predetermined values V1 and N1, respectively, when the shift control controller 1 is reset due to an instantaneous interruption of the power supply or the like, the predetermined control is performed. Actual gear ratio RTO for each cycle
Since the step motor drive position Astep is stored in the backup memory 10, the absolute value of the deviation between the actual gear ratio RTO immediately after the reset and the actual gear ratio RTO (RAM) stored in the backup memory 10 immediately before the reset is calculated. If the value is equal to or less than the predetermined value R1, the stepping motor drive position Astep (RAM) immediately before reset stored in the backup memory 10 at the same time as the actual gear ratio RTO (RAM) is set as the current drive position Astep. As compared with the case where the step motor drive position Astep is estimated from the actual gear ratio immediately after the reset as described above, the accuracy of the shift control can be improved even when the reset occurs during traveling. When the toroidal type is adopted as the step transmission, the actual speed ratio RTO and the step speed due to the influence of the torque shift during the reset are changed. It is possible to suppress the shift of the motor drive position Astep and restart the temporarily interrupted shift control with high accuracy.

Then, immediately after the reset, the actual speed ratio RT
Until the calculation of O is completed, the step motor drive position Ast
After the ep is held at the position immediately before the reset, the driving of the step motor 4 is prohibited, and after the calculation of the actual gear ratio RTO is performed,
By determining the step motor drive position Astep, the step motor drive position A
Since the shift control is resumed after the step is set, the temporarily suspended shift control can be resumed with higher accuracy.

The actual gear ratio RTO (R
AM) and the deviation ΔRTO of the actual gear ratio RTO immediately after reset.
If the absolute value of RTO exceeds the predetermined value R1, the stepping motor drive position Astep is estimated from the actual gear ratio RTO immediately after reset based on a map or the like, as in the above-described conventional example. Motor drive position A
The step does not largely deviate, and the shift control can be continued following the change of the gear ratio during the reset.

If the writing to the backup memory 10 is not performed normally, the step motor drive position Astep is estimated from the actual speed ratio RTO immediately after the reset based on a map or the like, as in the conventional example. Thus, although the control accuracy is reduced, fail-safe can be ensured by continuing the shift control.

In the above-described embodiment, the case where the toroidal type is used as the continuously variable transmission 2 has been described. However, although not shown, even if the V-belt type is used, the same operation and effect as above can be obtained. be able to.

In the above embodiment, the step motor 4 is used as an actuator for driving the shift control valve 60.
Although the example using was shown, it is not limited to this,
It may be a servomotor or the like.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a continuously variable transmission showing one embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a relationship between a step motor and a shift control mechanism of a toroidal-type continuously variable transmission.

FIG. 3 is a flowchart illustrating an example of control performed by a shift control controller, illustrating a main routine of the shift control.

FIG. 4 is a flowchart showing an example of control.
4 shows a subroutine of a step motor driving process.

FIG. 5 is a flowchart showing an example of a subroutine of a step motor driving process, similarly showing a normal initialization process.

FIG. 6 is a flowchart showing an example of a subroutine of a step motor driving process, similarly showing a high vehicle speed initialization process.

FIG. 7 is a flowchart showing an example of a subroutine of a step motor driving process, similarly showing an output process.

FIG. 8 shows a step motor drive position Astep and an actual gear ratio RT.
6 is a map showing the relationship of O.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shift controller 2 Continuously variable transmission 4 Step motor 5 Power roller 10 Backup memory 12 Origin switch 60 Shift control valve

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-178063 (JP, A) JP-A-5-346159 (JP, A) JP-A-5-118428 (JP, A) 144861 (JP, A) JP-A-7-310811 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (3)

(57) [Claims] A continuously variable transmission capable of continuously changing a speed ratio by an actuator; control means for calculating the speed ratio and driving an actuator based on the speed ratio; A first initialization unit that initializes the actuator when the control unit is reset; and a second initialization unit that continues driving the actuator when the control unit is reset while the vehicle is running. Wherein the second initialization means comprises means for calculating an actual gear ratio, and the actual gear ratio and the drive position of the actuator being controlled by a predetermined control cycle.
A non-volatile storage means for storing the data stored in the non-volatile storage means after each reset.
Absolute deviation between the gear ratio and the actual gear ratio calculated after reset
A deviation calculating means for calculating a pair value, wherein when the absolute value of the deviation is equal to or less than a predetermined value, the nonvolatile storage means is provided.
Actuator from the actuator drive position stored in the step
While the eta drive is restarted, the absolute value of the deviation
Exceeds the actual gear ratio calculated after reset.
From the actuator drive position estimated based on the
Of the continuously variable transmission characterized by restarting the driving of the eta
Transmission control device. 2. The method according to claim 1, wherein the second initialization means executes after reset.
Drive the actuator until the gear ratio is calculated.
The continuously variable transmission according to claim 1, wherein the transmission is prohibited.
Transmission control device. 3. The nonvolatile memory according to claim 2, wherein
Non-volatile storage means, comprising means for determining an abnormality of the storage means;
If it is determined that there is an error in the
Of the actuator estimated based on the actual transmission ratio
The feature is that the actuator drive is restarted from the moving position
The shift control device for a continuously variable transmission according to claim 1.