JP2005233372A - Setting method for hydraulic pressure characteristic value and automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct and set hydraulic pressure characteristic values to a safer (smaller transmission shock) side, when determining the hydraulic pressure characteristic values of an automatic transmission. <P>SOLUTION: A control part of the automatic transmission outputs a drive signal for performing predetermined learning of precharge pressure or standby pressure, and makes determination by learning conditions based on fluctuation of turbine rotational speed Nt to obtain the hydraulic pressure characteristic values (precharge maximum time T<SB>0</SB>before correction, standby pressure P<SB>0</SB>before correction). Subsequently, the control part of the automatic transmission refers to a correction table defined so as to escalate correction amount, reduces correction amount in a section to which the hydraulic pressure characteristic values belong, calculates hydraulic pressure characteristic values after correction (precharge maximum time T<SB>1</SB>before correction, standby pressure P<SB>1</SB>before correction) and performs learning setting. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for setting a hydraulic characteristic value of an automatic transmission and an automatic transmission capable of performing the method for setting the hydraulic characteristic value.

  A system is known in which an accumulator or the like is eliminated and the hydraulic pressure from a hydraulic pressure source is directly controlled by a solenoid valve, and the hydraulic pressure supplied to these friction engagement elements is controlled. In order to realize a smooth and highly responsive shift feeling, the hydraulic characteristic value for the hydraulic control (piston stroke control) of the friction engagement element is important.

  Therefore, a method for directly detecting the clutch piston position to learn the hydraulic characteristic value, a method for directly detecting the hydraulic pressure to use for learning the hydraulic characteristic value, and a method for directly detecting the torque to learn the hydraulic characteristic value. A method used for the above has been proposed. In dry friction clutches, it is well known to detect the value of the clutch stroke, but in the case of wet friction clutches, the stroke amount of the clutch piston is very small (for example, about 2 mm) and the position of the clutch piston is directly detected. In order to achieve this, the accuracy of the stroke sensor is required, resulting in an increase in cost, and even if the brake is good, it is difficult to apply to the clutch in practice. Further, in order to directly detect the hydraulic pressure value, it is necessary to consider a case where the hydraulic pressure sensor is expensive and the hydraulic pulsation is large, and there is a problem in reliability of the detected value itself. In addition, there is a problem that the same torque value is not always the same for the same hydraulic pressure value, and it is necessary to consider temperature dependency and the like. In addition, as for the method for directly detecting torque, an inexpensive and compact torque sensor has not been developed and is not put into practical use.

  In view of this, the applicant has disclosed a method capable of learning and setting a hydraulic pressure characteristic value based on a change in the turbine rotational speed Nt (Japanese Patent Laid-Open No. 2003-287119). The method described in the publication has many advantages over the above methods because the determination is performed based on fluctuations in the turbine rotational speed. In addition, in the same publication, the applicant specifically stated that the precharge maximum time used when quickly filling oil at the initial stage of the hydraulic pressure supply to the friction engagement element and the holding time immediately before the friction engagement element is engaged. We proposed a method for learning and setting the standby pressure.

JP 2003-287119 A

  According to the learning of the standby pressure described above, it is possible to drive the clutch piston gently and ignore the flow rate change using a stepped hydraulic waveform with a sufficiently long step interval with a small step pressure as a unit of measurement. By setting the state close to static, the return spring equivalent pressure can be determined precisely. The fluctuation of the turbine speed during learning is very gradual. From the viewpoint of preventing the judgment delay, it is necessary to reduce the threshold value of the change in the turbine speed included in the judgment condition. There are limitations due to recognition limitations. There is no problem if all the friction engagement elements have a margin with respect to the threshold value, but the margin is not constant for each friction engagement element, and depending on the friction engagement element, the relative rotational speed is small, There is a case where the torque distribution ratio with respect to the input torque is small, and there is a case where there is almost no margin for the threshold. In that case, if the step pressure of the stepped hydraulic waveform is increased at the expense of accuracy, the margin can be increased. However, there is currently a certain limit due to the required accuracy required on the transmission side. is there.

  In addition, for example, due to the operation of the accumulator, excessive consumption of flow due to leakage from the seal part (out of the O-ring, etc.), slow operation of the control valve (stickiness), or the actual pressure is small relative to the indicated pressure. The deceleration of the turbine rotational speed may be more gradual, which may cause a determination delay in learning of the standby pressure.

  For these determination delays, it is possible to set a standard in advance, and take measures to exclude (not use the learning value) if the value is out of the standard. For example, since the state in which force is applied to the friction engagement element continues even after passing through the point to be originally determined, the deceleration of the turbine speed eventually increases, and it is almost within the standard range. . However, since the determination delay is larger than the true value even if it is within the standard range, it contributes to the end per unit at the time of actual shift.

  A similar situation occurs when hydraulic vibration or the like occurs during learning of the precharge maximum time. In learning of the precharge maximum time, control is performed to bring the clutch piston into contact with the frictional engagement element at a speed that cannot be considered during normal gear shifting. For this reason, the deceleration of the turbine rotation speed is large and the judgment is never diverged. The maximum precharge time is somewhat longer even during hydraulic vibration, and the judgment can be made generally well. It is not possible to distinguish between occurrences of In most cases, the difference in the maximum precharge time due to the presence or absence of hydraulic vibration is small, and learning performed during hydraulic vibration falls within the product specification. If hydraulic vibration occurs during learning and the same level of hydraulic vibration occurs during actual shifting, there is reproducibility. If a shift shock occurs, it can be grasped as a problem of hydraulic vibration. However, if there is no reproducibility, for example, if the precharge time is learned and set longer than normal due to hydraulic vibration, and hydraulic vibration does not occur during actual shifting, an end hit occurs and a shift shock occurs. At this time, since no hydraulic vibration has occurred, a situation in which a fundamental measure cannot be taken occurs.

  In short, it is possible to take measures when the learning value in the product standard is large with respect to the true value that should be judged without losing the advantages of both the standby pressure and the precharge maximum time learning. It would be more preferable if possible. The present invention has been made in view of such circumstances, and an object of the present invention is to provide an improvement plan of a method for setting hydraulic characteristic values described in Japanese Patent Application Laid-Open No. 2003-287119 by the applicant. There is.

  According to a first aspect of the present invention that provides means for solving the above-described problems, a plurality of friction engagement elements that achieve a plurality of shift speeds by a combination of engagement and disengagement, and the friction engagement One of the friction engagement elements of the automatic transmission having a control unit that controls engagement / disengagement of the friction engagement element based on control of hydraulic pressure supplied to the element. Turbine rotation is transmitted to one side of the friction engagement element and the other side is fixed, a change in turbine rotation speed is detected by a turbine rotation speed sensor, and the friction engagement element is at least based on the fluctuation in turbine rotation speed. In the method for setting the hydraulic characteristic value of the automatic transmission that learns and sets the hydraulic characteristic value at the start of engagement, the hydraulic characteristic value obtained based on the fluctuation in the turbine rotational speed increases as the predetermined standard upper limit value is approached. Make corrections Setting the hydraulic pressure characteristic value of the dynamic transmission methods, and the automatic transmission capable of performing a is provided. That is, the control unit of the automatic transmission stores and holds a predetermined correction formula so that the correction amount increases as the hydraulic characteristic value increases, and the turbine rotation for the friction engagement element to be corrected is stored. A corrected hydraulic characteristic value obtained by substituting the hydraulic characteristic value obtained on the basis of the fluctuation of the number into the correction formula is learned and set.

  In addition, the control unit has a correction value for the hydraulic characteristic value that is determined so that the correction amount increases step by step for each of a plurality of sections provided from the upper standard side to the lower standard side within the standard range of the hydraulic characteristic value. May be stored and held, and the learning value may be set by subtracting the correction value corresponding to the category to which the hydraulic pressure characteristic value belongs from at least the hydraulic pressure characteristic value obtained based on the fluctuation of the turbine rotational speed. Still further, the control unit stores and holds a correction formula that is determined so that the correction amount increases as the hydraulic pressure characteristic value increases for each of the plurality of sections, and at least changes in the turbine rotational speed. The corrected hydraulic pressure characteristic value obtained by substituting the hydraulic pressure characteristic value obtained based on the above into a correction equation corresponding to the category to which the hydraulic pressure characteristic value belongs may be set as learning. It is preferable that the section, the correction value, and the correction formula are set so that the corrected hydraulic characteristic value is equal to or greater than the standard minimum value of the friction engagement element.

  According to the present invention, when obtaining the hydraulic pressure characteristic value of the friction engagement element to be corrected at least in the automatic transmission, the hydraulic pressure characteristic value can be corrected and set on the safer side (less gear shift shock). It becomes possible.

  Subsequently, the best embodiment of the present invention will be described. The automatic transmission (1 in FIG. 1) according to the present embodiment includes a transmission main body (2 in FIG. 1), a hydraulic pressure control unit (3 in FIG. 1) and an electronic control unit (4 in FIG. 1). ).

  The transmission main body (2 in FIG. 1) includes a first friction clutch C1, a second friction clutch C2, and a third friction clutch C3 as a plurality of (five) hydraulic engagement elements. The first friction brake B1 and the second friction brake B2 are incorporated to transmit engine power to the wheels.

  The hydraulic pressure control unit (3 in FIG. 1) is driven and controlled by the electronic control unit (4 in FIG. 1) to switch the internal hydraulic circuit and to provide a frictional engagement element (engagement / non-engagement) that supplies hydraulic pressure. And a hydraulic pressure to be supplied is controlled.

  The electronic control unit (4 in FIG. 1) includes a microcomputer, inputs the outputs of various sensors, and drives and controls the hydraulic control unit (3 in FIG. 1) based on these inputs. In the present embodiment, an input shaft (11 in FIG. 1) of the transmission main body (2 in FIG. 1), a turbine speed sensor (13 in FIG. 1) for detecting the turbine speed Nt of the turbine (10a in FIG. 1), and A position sensor (14 in FIG. 1) for detecting the travel range (R range, N range, D range) of the selector lever by the operation of the driver, an engine speed sensor (not shown) for detecting the engine speed Ne, An accelerator opening sensor (not shown) for detecting the accelerator opening is provided, and at least the turbine speed Nt and the travel range are input to the electronic control unit (4 in FIG. 1).

  Next, a method for setting the hydraulic pressure characteristic value in the automatic transmission (1 in FIG. 1) having the above configuration will be described. First, the electronic control unit (4 in FIG. 1) corresponds to a predetermined precharge pressure for the selected friction engagement element after confirming the hydraulic oil temperature and holding the engine speed at a predetermined speed. A drive signal is output to the hydraulic pressure control unit (3 in FIG. 1), and this state is maintained (see FIG. 3). As a result, the hydraulic oil is rapidly filled, and the selected friction engagement element starts to move toward the engagement side rapidly.

  As the hydraulic oil is rapidly filled and the hydraulic pressure rises, the friction engagement element changes to the engagement state, the torque converter 10 changes to the stall state, and the turbine speed Nt decreases. The electronic control unit (4 in FIG. 1) monitors the decrease in the turbine rotational speed Nt by the turbine rotational speed sensor (13 in FIG. 1), and the determination is satisfied or the decrease width of the turbine rotational speed Nt is a predetermined guard rotational speed. The output of the drive signal is continued until the value exceeds (see FIG. 3).

The electronic control unit (4 in FIG. 1), by the learning control of the precharge maximum time, the time when the fluctuation of the turbine rotational speed Nt satisfies a predetermined learning condition (see t3 in FIG. 3), that is, the selection An engagement start time of the frictional engagement element is obtained. Then, the pre-correction precharge maximum time T ₀ is obtained from the difference between the hydraulic control start time t1 at the precharge pressure and the engagement start time t3.

Here Further, the electronic control unit (4 in Fig. 1), when the friction engagement element which should perform the correction, the pre-correction pre-charge maximum time T ₀ obtained as described above, for example, the following formula by substituting such a correction formula as to seek the corrected pre-charge maximum time T _1, learns settings. Thereafter, the corrected pre-charge maximum time T ₁ is used when rapid filling of oil in the early supply of hydraulic pressure to the frictional engagement element.

The second term (T ₀ -a) ² / b on the right side of the above equation is for performing correction such that the correction amount becomes progressively larger in accordance with the precharge maximum time T ₀ before correction. is there. The constants a and b are corrected so that the correction amount becomes very small when the pre-correction precharge maximum time T ₀ is near the lower standard, and as the pre-correction precharge maximum time T ₀ approaches the upper standard. In order to increase the amount, the frictional engagement element is determined based on a standard lower limit value, an allowable standard width, and the like.

  Subsequently, the electronic control unit (4 in FIG. 1) sends a drive signal for the selected friction engagement element to the hydraulic control unit 3 so that the oil pressure of the friction engagement element gradually increases at every predetermined step-up time Δt. Output (see FIG. 4). As a result, the hydraulic oil is gradually filled, and the selected friction engagement element gradually moves to the engagement side.

  As the hydraulic oil is gradually filled and the hydraulic pressure rises, the friction engagement element gradually shifts to the engagement state, and when the predetermined pressure (standby pressure) is exceeded, the torque converter 10 changes to the stall state. Thus, the turbine speed Nt decreases. The electronic control unit (4 in FIG. 1) monitors the decrease in the turbine rotational speed Nt by the turbine rotational speed sensor (13 in FIG. 1), and the determination is satisfied or the decrease width of the turbine rotational speed Nt is equal to the predetermined guard rotational speed. The output of the drive signal is continued until it exceeds (see FIG. 4).

The electronic control unit (4 in FIG. 1), based on the standby pressure learning control, starts to decrease the turbine rotational speed Nt when the fluctuation of the turbine rotational speed Nt exceeds a predetermined threshold (see t13 in FIG. 3). That is, the engagement start time of the selected friction engagement element is obtained. Then, the pre-correction standby pressure P ₀ is obtained by the hydraulic pressure of the friction engagement element corresponding to the drive signal at the engagement start time.

Here Further, the electronic control unit (4 in Fig. 1), when the friction engagement element which should perform the correction, the uncorrected standby pressure P ₀ obtained as described above, for example, the following equation by substituting the correction equation, seeking corrected standby pressure P _1, learns settings. Thereafter, the corrected standby pressure P ₁ is the frictional engaging element is used when holding this in just prior to engagement.

The second term (P ₀ -c) ² / d on the right side of the above equation is for performing correction so that the correction amount becomes progressively larger in accordance with the magnitude of the pre-correction standby pressure P ₀ . The constants c and d are such that when the pre-correction standby pressure P ₀ is near the lower standard, the correction amount becomes very small, and the correction amount increases as the pre-correction standby pressure P ₀ approaches the upper standard. Thus, it is determined for each friction engagement element based on the standard lower limit value, the allowable standard width, and the like.

  As described above, in the present embodiment, the hydraulic characteristic value can be corrected and set on the safer side (with less shift shock).

  Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of an automatic transmission 1 according to an embodiment of the present invention. Referring to FIG. 1, the automatic transmission 1 includes a transmission main body 2, a hydraulic control unit 3 and an electronic control unit 4 that constitute a control unit.

  The transmission main body 2 is connected to an output shaft (not shown) of the engine and transmits engine power to the wheels. The transmission main body 2 includes a torque converter 10 connected to an output shaft of the engine, an input shaft 11 connected to a turbine 10a of the torque converter 10, and an output shaft connected to wheels via a differential device (not shown). 12, a first row double pinion planetary gear G 1 connected to the input shaft 11, a second row single pinion planetary gear G 2, and a third row single pinion planetary gear G 3. The transmission main body 2 includes a first friction clutch C1, a second friction clutch C2, a third friction clutch C3, and a first friction clutch as a plurality of (five) hydraulic engagement elements. A friction brake B1 and a second friction brake B2 are incorporated. In the transmission main body 2, engagement / disengagement of the first to third friction clutches C1 to C3 and the first and second friction brakes B1 and B2 is selected by the hydraulic control unit 3 and the electronic control unit 4. As a result, the gear stage described later is achieved. The first to third friction clutches C1 to C3 and the first and second friction brakes B1 and B2 are brought into an engaged state by being set to a high pressure by the hydraulic control unit 3, and are set to a low pressure. Thus, the disengaged state is established.

  The hydraulic control unit 3 is driven and controlled by the electronic control unit 4 to switch an internal hydraulic circuit and select a frictional engagement element that supplies hydraulic pressure (a frictional engagement element that is engaged / disengaged). Controls the hydraulic pressure to be supplied.

  The electronic control unit 4 includes a microcomputer, and outputs output values of various sensors. Based on these, the hydraulic control unit 3 is driven and controlled, and the lamp 15 provided on the driver's seat side is turned on. In this embodiment, a turbine rotational speed sensor 13 for detecting the turbine rotational speed Nt of the input shaft 11 (turbine 10a) is provided, and the electronic control unit 4 executes learning control based on the turbine rotational speed Nt. An example will be described.

  Further, the electronic control unit 4 stores a precharge maximum time and standby pressure correction table in the memory for each friction engagement element. The following table is a correction table for the precharge maximum time of the first friction brake B1 to be corrected among the friction engagement elements provided in the automatic transmission 1, and its standard width (tolerance) ± 150 ms (standard center) Is set to be divided into 6 sections every 50 ms, and the upper standard section is determined to be greatly reduced.

  The following table is a correction table for the standby pressure of the first friction brake B1 to be corrected among the friction engagement elements provided in the automatic transmission 1, and its standard width (tolerance) ± 20 kPa (standard center) Is divided into four sections for every 10 kPa, which is the step pressure of the stepped hydraulic waveform, and it is determined that the higher the section of the standard, the greater the reduction correction is made.

  In addition, the electronic control unit 4 stores a setting program for learning and setting the hydraulic pressure characteristic value. The program for setting the hydraulic pressure characteristic value is activated by a predetermined operation.

  FIG. 2 is a list showing the relationship between each friction engagement element provided in the automatic transmission 1 and the gear position. Referring to FIG. 2, the automatic transmission 1 has a reverse 1 having reverse, neutral, 1st to 4th underdrive, and 5th and 6th overdrive, depending on the set of friction engagement elements. It is possible to configure six speed stages and six forward speed stages. For example, when the third friction clutch C3 and the second friction brake B2 are engaged, the rotation of the output shaft 12 is reversed with respect to the input shaft 11 to reverse the vehicle. Further, for example, when only the second friction brake B2 is engaged, the neutral state is obtained, and when only the first friction clutch C1 and the second friction brake B2 are engaged, the first friction clutch C1 and the first friction clutch are shifted to the first speed. When only the brake B1 is engaged, the second speed is achieved. Similarly, when only the first and third friction clutches C1 and C3 are engaged, the third speed is obtained, and when only the first and second friction clutches C1 and C2 are engaged, the fourth speed is obtained. When only the third friction clutches C2 and C3 are engaged, the fifth speed is achieved, and when only the second friction clutch C2 and the first friction brake B1 are engaged, the sixth speed is achieved.

  For example, when shifting from the first speed to the second speed, the electronic control unit 4 disengages (releases) the second friction brake B2 and engages the first friction brake B1 via the hydraulic control unit 3. . When shifting from the second speed to the third speed, the first friction brake B1 is disengaged (released) and the third friction clutch C3 is engaged. Further, when shifting from the third speed to the fourth speed, the third friction clutch C3 is disengaged (released) and the second friction clutch C2 is engaged. Furthermore, when shifting from the fourth speed to the fifth speed, the first friction clutch C1 is disengaged (released) and the third friction clutch C3 is engaged. When shifting from the fifth speed to the sixth speed, the third friction clutch C3 is disengaged (released) and the first friction brake B1 is engaged.

  Next, the flow of learning setting of the hydraulic characteristic value in the automatic transmission having the above-described configuration will be described with an example in which the hydraulic characteristic value of the first friction brake 1 is learned and set. First, when a predetermined operation is received from the worker, the electronic control unit 4 is in a vehicle stop state, the engine speed is in an idling state, the sensor 13 such as oil temperature, turbine rotation, etc., the solenoid to be controlled, etc. The status of the given PTO or the like is confirmed, and if there is no problem, the standby state is set. In this state, when the travel range is switched from the N range to the D range by operating the selector lever, and when a predetermined learning start trigger such as an OD switch is operated, the electronic control unit 4 passes through the hydraulic control unit 3. The second friction clutch C2 is pre-engaged to form a hydraulic circuit that can select the fourth speed or higher (see FIG. 2).

  In this state, when the electronic control unit 4 shifts the first friction brake B1 to the engaged state via the hydraulic control unit 3, the b-axis side of the first friction brake B1 is engaged with the fixed case side. This reduces the rotational speed, that is, the turbine rotational speed Nt. Therefore, the hydraulic pressure characteristic value related to the first friction brake B1 can be obtained from the relationship between the control hydraulic pressure and the turbine rotational speed Nt when shifting to the engaged state.

  FIG. 3 is a diagram for explaining an outline of learning of the precharge maximum time. Referring to FIG. 3, at time t1, the electronic control unit 4 outputs a drive signal corresponding to a predetermined precharge pressure to the hydraulic control unit 3 for the first friction brake B1, and maintains this state. As the hydraulic oil is rapidly filled and the hydraulic pressure increases, the first friction brake B1 changes to the engaged state, the torque converter 10 changes to the stalled state, and the turbine speed Nt decreases. The electronic control unit 4 monitors the decrease in the turbine rotational speed Nt by the turbine rotational speed sensor 13, and until the determination is made or the decrease width of the turbine rotational speed Nt exceeds a predetermined guard rotational speed (time t2 in FIG. 4). Continue to output the drive signal.

The electronic control unit 4 calculates the time (determination establishment time) when the fluctuation of the turbine speed Nt between the times t1 and t2 satisfies a predetermined learning condition, that is, the engagement start time t3 of the first friction brake B1. Then, the pre-correction precharge maximum time T ₀ is obtained from the difference between the hydraulic control start time t1 at the precharge pressure and the engagement start time t3.

Here Further, the electronic control unit 4 refers to the correction table shown in Table 1 above, by subtracting the correction amount of the correction before correction Previous Group precharge maximum time T ₀ belongs from the pre-charge maximum time T ₀ calculates a corrected pre-charge maximum time T _1, learns settings. Thereafter, the corrected pre-charge maximum time T ₁ is used when rapid filling of oil in the early supply of hydraulic pressure to the frictional engagement element.

  FIG. 4 is a diagram for explaining an outline of standby pressure learning setting. Referring to FIG. 4, at time t11, the electronic control unit 4 drives the first friction brake B1 so that the hydraulic pressure of the first friction brake B1 gradually increases at a predetermined step pressure ΔP every predetermined step-up time Δt. A signal is output to the hydraulic control unit 3. As the hydraulic oil is gradually filled and the hydraulic pressure increases, the first friction brake B1 gradually shifts to the engaged state, and the torque converter 10 changes to the stalled state when a predetermined pressure (standby pressure) is exceeded. Thus, the turbine speed Nt decreases. The electronic control unit 4 monitors the decrease in the turbine rotational speed Nt by the turbine rotational speed sensor 13, and until the determination is made or the decrease width of the turbine rotational speed Nt exceeds a predetermined guard rotational speed (time t12 in FIG. 5). Continue to output the drive signal.

The electronic control unit 4 calculates the time (determination establishment time) when the fluctuation of the turbine speed Nt between the times t11 and t12 satisfies a predetermined learning condition, that is, the engagement start time t13 of the first friction brake B1. Then, by the hydraulic pressure of the first friction brake B1 of the drive signal corresponds in this engagement start time t13, the correction before the standby pressure P ₀ obtained.

Here Further, the electronic control unit 4 refers to the correction table shown in Table 2 above, by subtracting the correction amount of the pre-correction standby pressure P ₀ belongs segment from the uncorrected standby pressure P _0, the correction after the correction calculates the previous standby pressure P _1, learns settings. Thereafter, the corrected standby pressure P ₁ is the frictional engaging element is used when holding this in just prior to engagement.

  FIG. 5 and FIG. 6 are diagrams showing the influence of the correction of the above precharge maximum time and standby pressure. Referring to FIG. 5, it is shown that the larger the maximum precharge time (before correction) obtained by learning control is, the larger the reduction correction is. Therefore, the higher the risk of occurrence of a shift shock due to poor hydraulic vibration or piston movement, the more the precharge maximum time is corrected on the safe side (the side where no shift shock occurs). Is possible. In addition, referring to FIG. 6, similarly, it is shown that the higher the standby pressure (before correction) obtained by learning control, the higher the reduction pressure correction belongs.

  Therefore, it is possible to correct the standby pressure on the safe side (the side that does not cause a shift shock) as the risk of occurrence of a shift shock is high due to poor hydraulic vibration or piston movement. The overall quality improvement can be expected. In addition, it is possible to prevent a phenomenon in which the piston hits the end at the time of actual gear shifting, resulting in a shock and subsequent learning difficult to proceed.

  The correction process does not need to be applied to all the friction engagement elements, and it is sufficient to perform the correction process on the engagement elements having a small margin with respect to the threshold value.

  The learning control of the above precharge maximum time and standby pressure may be performed first, and either learning result should be compared with the reference value and reflected in the calculation of the other hydraulic characteristic value. Etc. are also possible. In addition, since the maximum precharge time is temperature-dependent, it is also preferable to perform further reduction correction by using a temperature map or the like so as to increase or decrease depending on the oil temperature.

  In the above-described embodiment, the entire standard range of hydraulic characteristic values is divided into a plurality of continuous sections, and an example using a correction table in which a large correction amount is set as the hydraulic characteristic value obtained by learning control increases. As described above, a section may be provided only on the upper side of the standard range of the hydraulic characteristic value, or a correction formula or the like applied to each section may be determined in place of the correction amount. For example, FIG. 7 is a diagram showing the effect of correction when the standby pressure is determined in the same manner as in the above-described embodiment, and when the correction equation is determined. A correction formula is set for each section so that the standby pressure after correction in the vicinity of the boundary does not reverse.

  Further, in the above-described embodiment, an example in which only the turbine rotational speed is used for learning the hydraulic characteristic value has been described. However, the present invention is not limited to the above-described method, and the engine rotational speed previously filed by the applicant. It is also applicable to learning of various other automatic transmissions such as a method for obtaining a hydraulic pressure characteristic value using a difference between the turbine speed and the turbine speed (Japanese Patent Application Nos. 2003-081939 and 2003-081967).

1 is a schematic diagram illustrating an overall configuration of an automatic transmission 1 according to an embodiment of the present invention. It is a list figure which shows the relationship between engagement / disengagement of each friction engagement element, and a gear stage. It is a figure for demonstrating the outline | summary of the learning setting of precharge maximum time. It is a figure for demonstrating the outline | summary of the learning setting of a standby pressure. It is a figure for demonstrating one correction method of the precharge maximum time. It is a figure for demonstrating one correction method of standby pressure. It is a figure for demonstrating another correction method of the precharge maximum time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic transmission 2 Transmission main body 3 Hydraulic control part 4 Electronic control part 10 Torque converter 10a Turbine 11 Input shaft 12 Output shaft 13 Turbine rotation sensor 14 Position sensor B1, B2 Friction brake C1, C2, C3 Friction clutch G1 Double pinion planetary gear G2, G3 Single pinion planetary gear

Claims (4)

A plurality of friction engagement elements that achieve a plurality of shift speeds by a combination of engagement and disengagement, and engagement / disengagement of the friction engagement elements based on control of hydraulic pressure supplied to the friction engagement elements One of the friction engagement elements of an automatic transmission having a control unit for controlling is disengaged to transmit the turbine rotation to one side of the friction engagement element and fix the other side, A hydraulic characteristic value setting method for an automatic transmission that detects fluctuations in turbine rotational speed by means of a rotational speed sensor and learns and sets hydraulic characteristic values at the start of engagement of the friction engagement element based on at least fluctuations in the turbine rotational speed In
A plurality of sections are provided from the upper side of the standard within the standard range of the hydraulic characteristic value to the lower side of the standard,
For each of the sections, a correction value of the hydraulic characteristic value is determined in advance so that the correction amount increases stepwise,
Learning setting by subtracting a correction value corresponding to the category to which the hydraulic pressure characteristic value belongs from at least the hydraulic pressure characteristic value obtained based on the fluctuation of the turbine rotational speed;
Setting method of hydraulic characteristic value of automatic transmission characterized by the above. A plurality of friction engagement elements that achieve a plurality of shift speeds by a combination of engagement and disengagement, and engagement / disengagement of the friction engagement elements based on control of hydraulic pressure supplied to the friction engagement elements One of the friction engagement elements of an automatic transmission having a control unit for controlling is disengaged to transmit the turbine rotation to one side of the friction engagement element and fix the other side, A hydraulic characteristic value setting method for an automatic transmission that detects fluctuations in turbine rotational speed by means of a rotational speed sensor and learns and sets hydraulic characteristic values at the start of engagement of the friction engagement element based on at least fluctuations in the turbine rotational speed In
Define a correction formula so that the correction amount increases as the hydraulic pressure characteristic value increases.
Learning and setting a corrected hydraulic pressure characteristic value obtained by substituting the hydraulic pressure characteristic value obtained based on at least the fluctuation of the turbine speed into the correction equation;
Setting method of hydraulic characteristic value of automatic transmission characterized by the above. A plurality of friction engagement elements that achieve a plurality of shift speeds by a combination of engagement and disengagement, and engagement / disengagement of the friction engagement elements based on control of hydraulic pressure supplied to the friction engagement elements One of the friction engagement elements of an automatic transmission having a control unit for controlling is disengaged to transmit the turbine rotation to one side of the friction engagement element and fix the other side, In an automatic transmission that detects a change in turbine rotation speed by a rotation speed sensor and learns and sets a hydraulic characteristic value at the start of engagement of the friction engagement element based on at least the fluctuation in the turbine rotation speed.
The control unit stores a correction value of the hydraulic characteristic value determined so that the correction amount is increased step by step for each of a plurality of sections provided from the upper side to the lower side of the standard within the standard range of the hydraulic characteristic value. Hold and
Learning setting by subtracting a correction value corresponding to the category to which the hydraulic pressure characteristic value belongs from at least the hydraulic pressure characteristic value obtained based on the fluctuation of the turbine rotational speed;
Automatic transmission characterized by. A plurality of friction engagement elements that achieve a plurality of shift speeds by a combination of engagement and disengagement, and engagement / disengagement of the friction engagement elements based on control of hydraulic pressure supplied to the friction engagement elements One of the friction engagement elements of an automatic transmission having a control unit for controlling is disengaged to transmit the turbine rotation to one side of the friction engagement element and fix the other side, In an automatic transmission that detects a change in turbine rotation speed by a rotation speed sensor and learns and sets a hydraulic characteristic value at the start of engagement of the friction engagement element based on at least the fluctuation in the turbine rotation speed.
The controller is
Store and hold a predetermined correction formula so that the correction amount increases as the hydraulic characteristic value increases,
Learning and setting a corrected hydraulic pressure characteristic value obtained by substituting the hydraulic pressure characteristic value obtained based on at least the fluctuation of the turbine speed into the correction equation;
Automatic transmission characterized by.

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