JP2001116131A - Initialization device for speed change control system in continuously variable transmission - Google Patents

Abstract

(57) [Problem] To prevent an adverse combination such as step-out due to an improper combination of a driving speed and a driving pattern of a step motor according to an oil temperature at the time of initialization. SOLUTION: An oil temperature is calculated at 21, a step motor driving speed is determined at 22 according to the oil temperature, and an oil temperature is calculated again at 23. In 24, check whether the oil temperature in 23 is normal temperature or low temperature,
If the temperature is low, select the low-temperature pattern as the step motor drive pattern at 25, and if it is normal temperature, select the normal-temperature pattern at 26. At 27, the drive patterns selected at 25 or 26 are sequentially output at a cycle corresponding to the drive speed determined at 22. The initialization is advanced by repeating 27 until it is determined that the initialization of the step motor has been completed in 28,
When the initialization is completed, at step 29, the step motor drive control for the normal shift mode is performed. Therefore, during the initialization, both the step motor drive speed and the drive pattern are held at the drive speed determined at 22 at the start of the initialization and the drive pattern determined at 25 or 26 at the start of the initialization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a device for initializing a shift control system of a continuously variable transmission.

[0002]

2. Description of the Related Art A speed change control system of a continuously variable transmission normally moves a step motor to a position corresponding to a target speed ratio by a speed change command corresponding to a target speed ratio determined according to a vehicle operating condition, and responds to the step motor. In general, the continuously variable transmission is configured to perform a continuously variable transmission toward a target gear ratio by a hydraulic pressure from a speed change control valve.

[0003] At this time, the stepping motor needs to generate a torque that overcomes the drag since the step motor needs to be stroked to a position corresponding to the target speed ratio against the drag from the transmission control valve. Incidentally, the above-described drag increases as the oil temperature decreases, and is relatively small at normal temperature. Therefore, the required torque of the step motor is large at low oil temperature,
It becomes smaller at normal temperature. On the other hand, the generated torque of the step motor is inversely proportional to the drive speed, and therefore the drive speed of the step motor is reduced at low oil temperature where the required torque of the step motor is large, and at room temperature where the required torque of the step motor is small. It is preferable to increase the driving speed of the stepping motor.
No. 42 and Japanese Patent Application Laid-Open No. Hei 10-225189. If this control is neglected, the step motor may be unable to respond to the shift command reliably due to the drag of the shift control valve, and a mismatch between the drive position of the step motor and the shift command may occur, resulting in random shift control. , A so-called step-out phenomenon occurs.

If only the step motor can be moved to a position corresponding to the target gear ratio, the drive speed of the step motor should always be reduced to increase the torque. However, the response of the step motor is poor. The shift performance is adversely affected, and also in this case, a mismatch between the drive position of the step motor and the shift command occurs, and the above-mentioned step-out phenomenon occurs.

The driving speed of the stepping motor is usually achieved by manipulating the driving cycle of the stepping motor, as is apparent from a comparison between FIG. 3 showing that at a low temperature and FIG. 4 showing it at a normal temperature. The drive speed is reduced by increasing the drive cycle of the step motor as shown in FIG. 3 to increase the step time interval, and at normal temperature, the drive cycle of the step motor is shortened as shown in FIG. The drive speed is increased by reducing the distance.

A step motor is also shown in FIGS. 5 and 6 in addition to FIGS. 3 and 4, but includes a first phase having terminals A and B and a second phase having terminals C and D. And a step motor which moves forward by one step when terminals in the same phase are simultaneously turned on and off.

On the other hand, the shift control system of the continuously variable transmission needs to be initialized in order to correct the above-mentioned step-out at the time of resetting by turning on an engine key switch or the like. As described in the publication, the stepping motor is once stepped further to the limit position on the low side than the lowest speed ratio position, and then the stepping motor is returned by a predetermined number of steps and set as an initial position, Based on this, the speed change control is performed by stepping the step motor several steps.

When the step motor is driven upon initialization of the shift control system (step motor),
It is necessary to control the drive speed of the step motor in accordance with the oil temperature in order to prevent loss of synchronism. On the other hand, when the drive speed of the step motor is low at the time of the initialization (for example, at a low temperature) (see FIG. 3), the step motor is continuously advanced as shown in FIG. However, since the rebound at the time of stopping at the limit position does not become large and there is no step-out caused by this, the initialization can be normally terminated. In the case where the driving speed control of the stepping motor is fast as in the case of normal temperature (see FIG. 4), if the stepping motor is continuously moved in the same manner, the resilience at the time of stopping at the limit position becomes large. This causes a step-out, and the initialization may not be performed normally.

Therefore, at normal temperature when the driving speed of the motor is increased, the driving pattern of the stepping motor is set as shown in FIG. 6 and the stepping motor is advanced by, for example, four steps as shown in FIG. As if
It is good to intervene a stop step. In this case, even at normal temperature where the driving speed of the motor is increased, the resilience input to the step motor at the time of stopping at the limit position is reduced, so that step-out caused by this is hard to occur, and Initialization can be performed normally even at normal temperature where the driving speed is increased.

In determining the drive speed and the drive pattern of the step motor at the time of the above-mentioned initialization, it is generally common practice to carry out this as shown in FIG. That is, first, in step 31, the oil temperature signal is read to calculate the oil temperature, and in step 32, the drive speed of the step motor (whether the low-speed step motor drive cycle shown in FIG. The step motor drive cycle for normal temperature shown in the figure should be determined), and in step 33, it is checked whether the oil temperature is normal temperature. If it is determined in step 33 that the temperature is not room temperature, that is, if the temperature is low, step 34
Then, the driving pattern for low temperature shown in FIG. 5 is selected as the driving pattern of the step motor, and when it is determined in step 33 that the driving temperature is normal temperature, the driving pattern for normal temperature shown in FIG. Pattern.

Next, at step 36, the oil temperature signal is read again to calculate the oil temperature, and at step 37, the driving speed of the step motor according to the oil temperature (whether the low-speed step motor driving cycle shown in FIG. Is to be set to the step motor drive cycle for normal temperature shown in FIG. 4). Further, in step 38, the drive patterns of the step motors selected in step 34 or 35 for each counter shown in FIG. 5 or 6 are sequentially output at a cycle corresponding to the step motor drive speed determined in step 37.

At step 39, it is checked whether or not the above-mentioned initialization of the transmission control system (step motor) has been completed, and the above-described steps 36 to 38 are repeated until the initialization is completed, whereby the initialization proceeds. When the initialization is completed, in step 40, step motor drive control for the normal speed change mode is performed.

[0013]

According to the above control, the drive speed of the step motor can be changed one by one according to the oil temperature in step 37 during the operation of the initialization. During operation, at the start of initialization, the pattern determined in step 34 or 35 is held (step 38), and the following problem occurs.

That is, when the initialization is started near a set temperature for determining whether the oil temperature is low or normal, especially when the initialization is started at a low temperature, the oil temperature enters the normal temperature range,
Or on of an engine starter switch 8 when the controller is reset instantaneously t ₂ by the oil temperature sensor value detected by the drop of the power supply voltage by (instant t ₁₎ initialization is started when it becomes a low temperature , instant t ₃ when driving pattern of the instantaneous t ₂ subsequent step motor to have kept driving pattern for low temperature shown in FIG. 5, the oil temperature sensor detection value in return of the power supply voltage returns to a value indicative of ambient temperature Next, the drive speed of the step motor is switched from the drive speed for low temperature (long drive motor drive cycle) shown in FIG. 3 to the drive speed for normal temperature (short step motor drive cycle) shown in FIG. As described above, when the stepping motor is driven by a combination of the low-temperature driving pattern and the normal-temperature driving speed, the above-mentioned step-out is most likely to occur, and a predetermined initialization can be performed by the step-out. The problem of disappearing occurs.

According to the first aspect of the present invention, the problem relating to the step-out during the initialization is solved without causing an unreasonable combination of the drive pattern and the drive speed of the step motor. It is an object of the present invention to propose an apparatus for initializing a shift control system in a continuously variable transmission.

According to a second aspect of the present invention, the driving pattern and the driving speed of the step motor during the initialization are:
It is an object of the present invention to propose an apparatus for initializing a shift control system in a continuously variable transmission that is optimized in relation to oil temperature.

[0017]

To achieve these objects, an initialization apparatus for a transmission control system in a continuously variable transmission according to a first aspect of the present invention comprises a step motor that responds to a shift command to control the continuously variable transmission to a target transmission ratio. The initialization at the time of reset of the shift control system for shifting gears toward is performed by stepping to a limit position further on the low side than the lowest speed ratio position of the stepping motor and returning to a predetermined step thereafter, and during the initialization, In the initialization apparatus for the shift control system in the continuously variable transmission, the drive speed and the drive pattern of the step motor are determined according to the oil temperature at the same timing. And that the determined drive speed and drive pattern of the step motor are maintained unchanged during initialization. Is shall.

According to a second aspect of the present invention, there is provided an apparatus for initializing a shift control system in a continuously variable transmission according to the first aspect, wherein the oil temperature at the start of initialization is used as the oil temperature at the same timing. Things.

[0019]

According to the first aspect of the invention, when the shift control system of the continuously variable transmission is initialized by the stepping drive of the step motor, the drive speed and the drive pattern of the step motor are determined according to the oil temperature. At this time, the drive speed and drive pattern of the step motor are determined according to the oil temperature at the same timing, and the determined drive speed and drive pattern of the step motor are maintained unchanged during initialization. Therefore, during the initialization of the shift control system, if the drive pattern of the step motor is for a low temperature (for normal temperature), the drive speed of the step motor is also always for a low temperature (for normal temperature). That is, during the initialization, for example, the drive speed of the step motor is switched from the drive speed for the low temperature to the drive speed for the normal temperature while the drive pattern of the step motor is maintained at the drive pattern for the low temperature. Such a situation can be avoided. Therefore, the combination of the drive pattern and the drive speed of the step motor does not cause the above-described step-out, and the problem that the predetermined initialization cannot be performed due to the step-out can be solved. .

In the second invention, since the oil temperature at the start of initialization is used as the oil temperature at the same timing, the drive pattern and the drive speed of the step motor during initialization are optimized in relation to the oil temperature. And initialization can be appropriately performed.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a continuously variable transmission control system provided with an initialization device for a continuously variable transmission according to an embodiment of the present invention, wherein 1 is a transmission control valve, 2 is a step motor, and 3 is an initialization device. It is a stopper that provides a step motor limit position. Note that the step motor limit position may be provided by a hardware limit of the shift control mechanism, not by the stopper 3. The speed change control valve 1 has a valve body 1a articulated in the middle of a link 10. One end of the link 10 is articulated to a speed change command valve body 11 which is stroked by a step motor 2 via a rack and pinion 4. The other end of the link 10 is connected to the pulley movable flange 13 of the V-belt type continuously variable transmission 12 to constitute a transmission control mechanism as usual. Thus, the valve element 1a of the shift control valve 1 is driven to a stroke position corresponding to the number of drive steps of the step motor 2 (target speed ratio i ^* ), and both pulley groove widths of the V-belt type continuously variable transmission 12 are hydraulically driven. And the speed of the continuously variable transmission is controlled to achieve the target speed ratio i ^* . The progress of the shift is fed back to the valve body 1a of the shift control valve 1 via the link 10, and when the continuously variable transmission reaches the target speed ratio i ^* , the valve body 1a of the shift control valve 1 returns to the original position. By doing so, the shift is ended.

The target transmission ratio i ^* is determined by the transmission controller 5, and the controller 5 further performs initialization of the transmission control system (step motor 2), which is the target of the present invention, which will be described later. Because of this, the controller 5
A signal from a throttle opening sensor 6 for detecting a throttle opening TVO of the engine, a signal from a vehicle speed sensor 7 for detecting a vehicle speed VSP, a signal from an oil temperature sensor 8 for detecting a transmission working oil temperature TEMP, and a continuously variable signal. A signal from a range sensor 9 for detecting a transmission selection range (forward travel range, reverse travel range, neutral range, parking range) is input.

The controller 5 performs normal stepless speed change control based on the input information from these sensors, and corrects the step-out of the speed change control system (step motor 2) at the time of resetting by turning on an engine key switch or the like. Perform the necessary initialization. At the time of this initialization, the controller 5 steps the step motor 2 once so that the shift control valve element 1a is further stroked to the lower side (left side in the figure) from the lowest speed ratio position shown in FIG. Then, the position where the step motor 2 is returned by a predetermined number of steps is set as an initial position, and the initialization is completed. Then, the controller 5 shifts the continuously variable transmission to the target gear ratio by moving the step motor 2 by the number of steps corresponding to the target gear ratio i ^{* based} on the initial position.

When the transmission control system (step motor 2) is initialized, the controller 5 determines the drive speed and drive pattern of the step motor 2 by executing the control program shown in FIG. First, in step 21, the oil temperature signal from the sensor 8 is read to calculate the oil temperature TEMP, and in step 22, the driving speed of the step motor 2 (in accordance with the driving temperature of the step motor for low temperature shown in FIG. Is determined, whether the driving cycle should be set to the normal temperature step motor shown in FIG. 4), and in step 23, the oil temperature signal from the sensor 8 is read again to calculate the oil temperature TEMP.

Next, in step 24, step 2
It is checked whether or not the oil temperature TEMP in Step 3 is normal temperature.
If it is determined in step 24 that the temperature is not room temperature, that is, if the temperature is low, in step 25, the drive pattern for low temperature shown in FIG. 5 is selected as the drive pattern of the step motor 2 and if it is determined in step 24 that the temperature is room temperature, step 26 In FIG. 6, the driving pattern for normal temperature shown in FIG.

Next, in step 27, step 2
The drive pattern of the step motor 2 selected in step 5 or 26 for each counter shown in FIG. 5 or 6 is sequentially output at a cycle corresponding to the step motor drive speed determined in step 22.

In step 28, it is checked whether or not the above-mentioned initialization of the transmission control system (step motor 2) has been completed, and the above-described step 27 is repeated until the initialization has been completed, whereby the initialization proceeds. When the initialization is completed, at step 29, step motor drive control for the normal speed change mode is performed.

Therefore, according to the drive control of the step motor according to the above-described embodiment, during the initialization, both the drive speed and the drive pattern of the step motor 2 are determined at the start of the initialization. The drive speed and the step motor drive pattern determined in step 25 or 26 at the start of initialization are also held. For this reason, during the initialization of the shift control system (step motor 2), if the drive pattern of the step motor 2 is for low temperature (for normal temperature), the drive speed of the step motor must also be for low temperature (for normal temperature). ), And during the initialization, for example, the drive pattern of the step motor 2 is maintained at the low-temperature drive pattern, but the drive speed of the step motor 2 is changed from the low-temperature drive speed to the normal temperature. Can be avoided. Therefore, the combination of the drive pattern and the drive speed of the step motor does not cause the above-described step-out, and the problem that the predetermined initialization cannot be performed due to the step-out can be solved. .

In this embodiment, the drive pattern and the drive speed of the step motor 2 are determined based on the oil temperature at the start of the initialization. Can be optimized in relation to oil temperature and initialization can be performed properly.

In the above embodiment, the case where the continuously variable transmission is a V-belt type continuously variable transmission has been described.
The present invention is not limited to this, and it is needless to say that the present invention can be similarly applied to other types of continuously variable transmissions such as a toroidal type continuously variable transmission.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a continuously variable transmission control system of a continuously variable transmission including an initialization device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a program executed by the transmission controller to determine a drive pattern and a drive speed of a step motor in the embodiment.

FIG. 3 is a time chart illustrating a preferred stepping form of a step motor during initialization at a low oil temperature.

FIG. 4 is a time chart illustrating a preferred stepping mode of a step motor during initialization at normal temperature.

FIG. 5 is an explanatory diagram illustrating a drive pattern of a step motor that is preferable during initialization at a low oil temperature. .

FIG. 6 is an explanatory diagram exemplifying a preferable drive pattern of a step motor during initialization at normal temperature.

FIG. 7 is a flowchart showing a conventional general step motor driving pattern and a procedure for determining a step motor driving speed.

8 is an operation time chart used to explain the adverse effect when the drive pattern and the drive speed of the step motor are determined by the conventional method of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shift control valve 2 Step motor 3 Stopper 4 Rack & pinion 5 Transmission controller 6 Throttle opening sensor 7 Vehicle speed sensor 8 Oil temperature sensor 9 Range sensor 10 Link 11 Shift command valve 12 V belt type continuously variable transmission 13 Pulley movable flange

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masato Koga Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Satoshi Takizawa 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture 72) Inventor Shigeki Shimanaka 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Inside Nissan Motor Co., Ltd. 2F, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. F term (reference) 3J052 AA04 CA22 GC73 HA11 KA09

Claims (2)

[Claims] An initialization at the time of reset of a shift control system for shifting a continuously variable transmission toward a target speed ratio by a step motor responding to a speed change command is performed at a position further lower than the lowest speed ratio position of the step motor. This is executed by stepping to the limit position and then returning to a predetermined step, and the drive control speed and the drive pattern of the step motor during the initialization are determined according to the oil temperature. In the initialization apparatus, the drive speed and the drive pattern of the step motor are determined according to the oil temperature at the same timing, and the determined drive speed and the drive pattern of the step motor are maintained unchanged during initialization. A shift control system initialization device for a continuously variable transmission. 2. The apparatus according to claim 1, wherein the oil temperature at the start of initialization is used as the oil temperature at the same timing.