JP3700494B2 - Initializing device for shift control system in continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement proposal for an apparatus for initializing a shift control system of a continuously variable transmission.
[0002]
[Prior art]
The transmission control system of a continuously variable transmission normally has a shift control valve that moves the step motor to a position corresponding to the target speed ratio in response to a speed change command corresponding to the target speed ratio determined according to the vehicle operating state. In general, the continuously variable transmission is continuously variable-shifted toward the target gear ratio with the hydraulic pressure.
[0003]
At this time, the step motor needs to generate a torque that overcomes the drag because it needs to stroke the drag to a position corresponding to the target gear ratio against the drag from the transmission control valve.
By the way, the above-mentioned drag increases as the oil temperature is low, and is relatively small at normal temperature. Therefore, the required torque of the step motor is large at low oil temperature and small at normal temperature.
On the other hand, the generated torque of the step motor and the drive speed are inversely proportional, and therefore the step motor drive speed is slowed at low oil temperatures where the step motor required torque is large, and the step motor required torque becomes small at room temperature. It is preferable to increase the driving speed of the step motor. For example, a technique for determining the driving speed of the step motor in accordance with the oil temperature is conventionally disclosed in, for example, Japanese Patent Application Laid-Open Nos. 8-17842 and 10-225189. Proposed.
If this control is neglected, the step motor may lose the drag of the speed change control valve and may not respond to the speed change command reliably, resulting in a mismatch between the drive position of the step motor and the speed change command. This causes a so-called step-out phenomenon.
[0004]
If it is only possible to stroke the step motor to a position corresponding to the target gear ratio, the step motor drive speed may be constantly slowed to increase the torque. In this case as well, there is a mismatch between the drive position of the step motor and the shift command, and the above-mentioned step-out phenomenon occurs.
[0005]
The step motor drive speed is normally achieved by manipulating the step motor drive cycle, as is apparent from a comparison of FIG. 3 showing that at low temperature and FIG. 4 showing it at room temperature, and FIG. As shown in Fig. 4, the drive speed is slowed by increasing the step motor drive cycle and increasing the step time interval, and at room temperature, the step motor drive cycle is shortened and the step time interval is reduced as shown in FIG. To increase the driving speed.
[0006]
As shown in FIG. 5 and FIG. 6 in addition to FIG. 3 and FIG. 4, the step motor usually has a first phase consisting of A terminal and B terminal and a second phase consisting of C terminal and D terminal. A two-phase step motor is used, and this step motor advances one step when the terminals in the same phase are simultaneously switched ON and OFF.
[0007]
On the other hand, the speed change 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. This initialization is disclosed in, for example, Japanese Patent Laid-Open No. 8-17863. As described, once the step motor is stepped further to the limit position on the low side than the lowest speed gear ratio position, then the position where the step motor is returned by a predetermined number of steps is set as the initial position, and this is used as a reference. The gear shift control is performed by stepping the step motor several steps.
[0008]
Even when the step motor is driven to initialize the speed change control system (step motor), it is necessary to control the drive speed of the step motor in accordance with the oil temperature to prevent step-out.
On the other hand, if the drive speed of the step motor is slow (see FIG. 3), such as at low temperatures, at the time of initialization, the drive pattern shown in FIG. 5 is used to continuously advance the step motor as shown in FIG. However, since there is no great impact at the time of stopping at the limit position and no step-out occurs due to this, the initialization can be completed normally.
Therefore, when the step motor drive speed control is fast as at normal temperature (see FIG. 4), if the step motor is continuously advanced in the same manner, the impact at the time of stopping at the limit position increases. This causes a step-out, and initialization may not be performed normally.
[0009]
Therefore, at room temperature when the motor drive speed is increased, the drive pattern of the step motor is as shown in FIG. 6, and the step motor is stepped, for example, by 4 steps as shown in FIG. It is better to intervene a stop step.
In this case, even when the motor driving speed is increased at room temperature, the elastic force input to the step motor is reduced when the motor is stopped at the limit position, so that the step-out caused by this is less likely to occur. Initialization can be performed normally even at room temperature where the drive speed is increased.
[0010]
When determining the driving speed and driving pattern of the step motor at the time of the above initialization, it is common sense to execute this as shown in FIG.
That is, first, at step 31, the oil temperature signal is read and the oil temperature is calculated. At step 32, the step motor driving speed (the step motor driving cycle for low temperature shown in FIG. In step 33, it is checked whether or not the oil temperature is normal.
If it is determined in step 33 that the temperature is not normal, that is, if the temperature is low, in step 34, the driving pattern for low temperature shown in FIG. The drive pattern for room temperature shown in FIG. 6 is a drive pattern for the step motor.
[0011]
Next, at step 36, the oil temperature signal is read again to calculate the oil temperature. At step 37, the step motor drive speed (the step motor drive cycle for low temperature shown in FIG. The step motor driving cycle for room temperature to be shown) should be determined.
Further, in step 38, the drive pattern for each counter shown in FIG. 5 or 6 of the step motor selected in step 34 or 35 is sequentially output at a cycle corresponding to the step motor drive speed determined in step 37.
[0012]
In step 39, it is checked whether or not the above-described initialization of the shift control system (step motor) is completed, and the initialization is advanced by repeating the above steps 36 to 38 until the initialization is completed.
When initialization is completed, in step 40, step motor drive control for the normal transmission mode is performed.
[0013]
[Problems to be solved by the invention]
By the way, according to the control described above, the driving speed of the step motor during initialization can be changed step by step in accordance with the oil temperature in step 37. However, the driving pattern of the step motor can be changed at the start of initialization during the initialization operation. The pattern determined in step 34 or 35 is held (step 38), resulting in the following problems.
[0014]
That is, when initialization is started near the set temperature for determining whether the oil temperature is low or normal temperature, the oil temperature enters the normal temperature range immediately after the initialization is started especially at low temperature, or FIG. when the controller is reset oil temperature sensor detection value instantaneously t ₂ is the initialization is started when it becomes low temperature drop of the power supply voltage from investing the engine starter switch (instant t ₁₎ as shown, instant t ₂ to drive pattern subsequent step motor is kept driven pattern for low temperature shown in FIG. 5, the oil temperature sensor detection value in return of the power supply voltage of the step motor instantaneously t ₃ when returning to a value indicating a normal temperature The driving speed is switched from the driving speed for low temperature shown in FIG. 3 (long step motor driving cycle) to the driving speed for normal temperature shown in FIG. 4 (short step motor driving cycle).
Thus, when the step motor is driven by a combination of the driving pattern for low temperature and the driving speed for normal temperature, the above-mentioned step out is most likely to occur, and predetermined initialization can be performed by such step out. The problem of disappearing.
[0015]
The first aspect of the present invention is a continuously variable transmission that solves the problem regarding the step-out during the initialization so that an unreasonable combination of the drive pattern and the drive speed of the step motor does not occur. An object of the present invention is to propose an initialization device for a shift control system in a machine.
[0016]
According to a second aspect of the present invention, there is provided a shift control system for a continuously variable transmission in which the drive pattern and drive speed of the step motor during initialization are optimized in relation to the oil temperature. The purpose is to propose an initialization device.
[0017]
[Means for Solving the Problems]
For these purposes, first, the initialization device for the shift control system in the continuously variable transmission of the first invention is:
Initialization at the time of reset of the speed change control system that shifts the continuously variable transmission toward the target speed ratio with the step motor that responds to the speed change command is carried out to the limit position on the low side further than the lowest speed speed ratio position of the step motor. In an initialization device for a shift control system in a continuously variable transmission, which is executed by advance and return of a predetermined step thereafter, and determines the drive speed and drive pattern of the step motor during the initialization according to the oil temperature,
The step motor drive speed and drive pattern are determined according to the oil temperature at the same timing, and the determined step motor drive speed and drive pattern are maintained unchanged during initialization. is there.
[0018]
An initialization device for a shift control system in a continuously variable transmission according to a second aspect of the present invention,
The oil temperature at the start of initialization is used as the oil temperature at the same timing.
[0019]
【The invention's effect】
In the first invention, when the speed change control system of the continuously variable transmission is initialized by the stepping drive of the step motor, the step motor drive speed and drive pattern are determined according to the oil temperature. The drive speed and drive pattern 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.
For this reason, during the initialization of the shift control system, if the drive pattern of the step motor is for low temperature (for room temperature), the drive speed of the step motor must always be for low temperature (for room temperature). During initialization, for example, the step motor drive pattern is maintained at the low temperature drive pattern, but the step motor drive speed switches from the low temperature drive speed to the normal temperature drive speed. Such a situation can be avoided.
Therefore, the combination of the driving pattern and the driving speed of the step motor does not cause the above-mentioned step-out, and the problem that the predetermined initialization cannot be performed by the step-out can be solved. .
[0020]
In the second invention, since the oil temperature at the start of initialization is used as the oil temperature at the same timing, it is possible to optimize the drive pattern and drive speed of the step motor during the initialization in relation to the oil temperature. It is possible to perform initialization properly.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a continuously variable transmission control system having 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 stepping motor, and 3 is for initialization. It is a stopper that provides a step motor limit position.
The step motor limit position may be provided not by the stopper 3 but by the hardware limit of the speed change control mechanism.
The speed change control valve 1 includes a valve body 1a that is articulated in the middle of the link 10, and one end of the link 10 is articulated to a speed change command valve body 11 that is stroked by the step motor 2 via the 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 speed change control valve 1 is driven to a stroke position corresponding to the number of drive steps (target speed ratio i ^* ) of the step motor 2, and both pulley groove widths of the V-belt type continuously variable transmission 12 are hydraulically controlled. , And the transmission control of the continuously variable transmission is performed so that the target gear ratio i ^* is obtained.
The progress of the speed change is fed back to the valve body 1a of the speed change control valve 1 via the link 10, and the valve body 1a of the speed change control valve 1 returns to the original position when the continuously variable transmission reaches the target speed ratio i ^*. This completes the shift.
[0022]
The target speed ratio i ^* is determined by the transmission controller 5, and the controller 5 also performs initialization, which will be described later, of the speed change control system (step motor 2) targeted by the present invention.
For this reason, the controller 5 has a signal from the throttle opening sensor 6 that detects the throttle opening TVO of the engine, a signal from the vehicle speed sensor 7 that detects the vehicle speed VSP, and an oil temperature sensor 8 that detects the transmission operating oil temperature TEMP. And a signal from the range sensor 9 for detecting a continuously variable transmission selection range (forward travel range, reverse travel range, neutral range, parking range).
[0023]
The controller 5 performs normal continuously variable transmission control based on input information from these sensors, and is necessary for correcting the step-out of the transmission control system (step motor 2) at the time of resetting by turning on an engine key switch or the like. Perform initial initialization.
At the time of initialization, the controller 5 temporarily steps the step motor 2 so that the shift control valve body 1a is stroked further to the low side (left side in the figure) than the lowest speed gear ratio position shown in the figure, and is defined by the stopper 3. After the limit position is set, the position where the step motor 2 is returned by a predetermined number of steps is set as the initial position, and the initialization is completed.
The controller 5 shifts the continuously variable transmission to the target gear ratio by causing the step motor 2 to step by the number of steps corresponding to the target gear ratio i ^* with reference to the initial position.
[0024]
In initializing the speed change control system (step motor 2), the controller 5 determines the drive speed and drive pattern of the step motor 2 by executing the control program of FIG.
First, at step 21, the oil temperature signal from the sensor 8 is read to calculate the oil temperature TEMP, and at step 22, the driving speed of the step motor 2 (in accordance with the low temperature step motor driving cycle shown in FIG. 3) according to the oil temperature TEMP. In step 23, the oil temperature signal from the sensor 8 is read again to calculate the oil temperature TEMP.
[0025]
Next, in step 24, it is checked whether or not the oil temperature TEMP in step 23 is normal temperature.
If it is determined in step 24 that the temperature is not normal, that is, if the temperature is low, in step 25, the drive pattern for low temperature shown in FIG. In FIG. 6, the drive pattern for room temperature shown in FIG.
[0026]
Next, in step 27, the drive pattern for each counter shown in FIG. 5 or 6 of the step motor 2 selected in step 25 or 26 is sequentially output at a cycle corresponding to the step motor drive speed determined in step 22.
[0027]
In step 28, it is checked whether or not the above-described initialization of the shift control system (step motor 2) is completed, and the initialization is advanced by repeating step 27 until the initialization is completed.
When initialization is completed, in step 29, step motor drive control for the normal transmission mode is performed.
[0028]
Therefore, according to the drive control of the step motor according to the present embodiment described above, during the initialization, both the drive speed and drive pattern of the step motor 2 are the step motor drive speed determined in step 22 at the start of initialization, Similarly, at the start of initialization, the step motor drive pattern determined in step 25 or 26 is 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 temperatures (for room temperature), the step motor drive speed must also be for low temperatures (for room temperature). During the initialization, for example, the driving pattern of the step motor 2 is kept at the driving pattern for low temperature, but the driving speed of the step motor 2 is changed from the driving speed for low temperature to the normal temperature. It is possible to avoid the occurrence of a situation where the driving speed is switched to the normal driving speed.
Therefore, the combination of the driving pattern and the driving speed of the step motor does not cause the above-mentioned step-out, and the problem that the predetermined initialization cannot be performed by the step-out can be solved. .
[0029]
In the present embodiment, in particular, since the drive pattern and drive speed of step motor 2 are determined based on the oil temperature at the start of initialization, the drive pattern and drive speed of step motor 2 during initialization are determined according to the oil temperature. And can be made to perform the initialization appropriately.
[0030]
In the above-described embodiment, the case where the continuously variable transmission is a V-belt continuously variable transmission has been described. However, the present invention is not limited to this, and other types of continuously variable transmissions such as toroidal continuously variable transmissions are also described. Of course, the present invention is equally applicable.
[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 step motor drive pattern and drive speed in the embodiment;
FIG. 3 is a time chart exemplifying a stepping mode of a preferred step motor during initialization at a low oil temperature.
FIG. 4 is a time chart illustrating a preferred step motor stepping mode during initialization at room temperature;
FIG. 5 is an explanatory diagram illustrating a preferred step motor drive pattern during initialization at a low oil temperature; .
FIG. 6 is an explanatory diagram illustrating a preferred step motor drive pattern during initialization at room temperature;
FIG. 7 is a flowchart showing a procedure for determining a conventional general step motor drive pattern and step motor drive speed.
8 is an operation time chart used to explain the adverse effects of determining the step motor drive pattern and step motor drive speed according to 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 links
11 Shift command valve
12 V belt type continuously variable transmission
13 Pulley movable flange

Claims (2)

Initialization at the time of reset of the speed change control system that shifts the continuously variable transmission toward the target speed ratio with the step motor that responds to the speed change command is carried out to the limit position on the low side further than the lowest speed speed ratio position of the step motor. In an initialization device for a shift control system in a continuously variable transmission, which is executed by advance and return of a predetermined step thereafter, and determines the drive speed and drive pattern of the step motor during the initialization according to the oil temperature,
The stepless drive speed and drive pattern are determined according to the oil temperature at the same timing, and the determined step motor drive speed and drive pattern are maintained unchanged during initialization. An initialization device for a shift control system in a transmission. The initialization apparatus for a shift control system in a continuously variable transmission according to claim 1, wherein the oil temperature at the start of initialization is used as the oil temperature at the same timing.

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