JP2888147B2 - Learning method of hydraulic control characteristics of automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for learning a control hydraulic pressure characteristic of an automatic transmission.

[0002]

2. Description of the Related Art In an automatic transmission for an automobile, a transmission mechanism using a planetary gear is generally used. A sun gear or a planetary gear is provided by a hydraulic friction engagement element such as a hydraulic wet multi-plate clutch, a brake, or a hydraulic band brake. A desired gear position is obtained by engaging or releasing a carrier or the like.

Normally, a hydraulic friction engagement element of an automatic transmission uses a line pressure generated by a hydraulic pump rotating together with a crankshaft of an engine as a drive source. In an electronic control type, the drive control is performed by hydraulic control means. This is performed by a certain electromagnetic hydraulic control valve (hereinafter, referred to as an electromagnetic valve). That is, by applying duty control to the solenoid valve, the line pressure is reduced at a predetermined rate to generate an apply pressure and a release pressure, and the supply and supply of the applied pressure and the release of the hydraulic clutch and the hydraulic brake are performed. .

[0004] Shifting is performed by switching the operating hydraulic clutch or hydraulic brake, that is, by engaging one hydraulic friction engagement element while releasing the other hydraulic friction engagement element. For example, when shifting up from the second gear to the third gear, the hydraulic pressure is released from the hydraulic engagement element (hereinafter referred to as the disengagement side engaging element) that establishes the second gear, and the engagement is released. The supply pressure is applied to a hydraulic engagement element (hereinafter, referred to as a coupling-side engagement element) that establishes the third speed, and the hydraulic engagement element is engaged. By the re-grip operation of the hydraulic clutch, the transmission path of the engine torque is switched, and the upshift is completed.

[0005]

As described above, the hydraulic pressure supplied to the hydraulic friction engagement element is obtained by controlling the duty of the solenoid valve. However, the solenoid valve itself, the transmission mechanism, the control valve and the like are obtained. Because there are individual differences,
The value of the supply oil pressure with respect to the drive duty ratio is not always constant, and within the range shown by the broken line in FIG.
Varies from N up and down. Therefore, conventionally, feedback control is performed when the solenoid valve is driven, and learning correction of the drive duty ratio is performed based on the deviation between the actual turbine speed change rate and the target turbine speed change rate at this time.

However, when a new vehicle has a short running distance, or when the running distance is short due to a battery being removed during maintenance or the like, such learning correction is not sufficiently performed, and the drive duty ratio is not appropriate. The value was deviated from the value, and the shift feeling was likely to be poor. Also,
In downshifting and upshifting at extremely low speeds, there is no time margin because the difference in turbine speed required for shifting is very small, and feedback control is hardly performed.
Therefore, under such conditions, learning correction of the drive duty ratio cannot be performed, and the shift quality is degraded.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a method of learning the hydraulic control characteristics of an automatic transmission, so that optimal shift control is always performed irrespective of aging of solenoid valves and various parts of the transmission. The purpose is to realize.

[0008]

According to the first aspect of the present invention, in order to achieve this object, a plurality of vehicles are interposed between an engine and a driving wheel of a vehicle via a fluid coupling, and a plurality of vehicles are provided in combination. Hydraulic control of an automatic transmission including a plurality of hydraulic friction engagement elements for achieving a shift speed and a plurality of hydraulic control means for controlling a hydraulic pressure supplied to the hydraulic friction engagement elements based on a drive signal from a control device In the characteristic learning method,
When the engine is in a predetermined operating state and the vehicle is in a stopped state, the first hydraulic control unit is driven so that an input shaft rotation speed of the automatic transmission becomes a predetermined target rotation speed, and Adjusting the supply hydraulic pressure to the first hydraulic friction engagement element among the hydraulic friction engagement elements; and adjusting the supply hydraulic pressure to the first hydraulic control means when the input shaft rotation speed matches the target rotation speed. Calculating a deviation of the drive signal from the reference signal, and calculating a correction amount of the drive signal for the first hydraulic control means according to the deviation.

According to a second aspect of the present invention, in the method for learning the hydraulic control characteristics of the automatic transmission according to the first aspect, the correction amount of the drive signal is set to another hydraulic control means of the plurality of hydraulic control means. We propose one characterized by being determined sequentially for each. According to a third aspect of the present invention, in the method for learning the hydraulic control characteristic of the automatic transmission according to the first aspect, the first hydraulic friction engagement element is configured to engage one of the plurality of shift speeds by engagement thereof. The learning method further includes a step of once establishing the one shift speed, and after the at least one shift speed is achieved, the first hydraulic friction engagement element It is proposed that the step of adjusting the supply hydraulic pressure is performed.

Preferably , the method for learning the hydraulic control characteristics of an automatic transmission according to claim 1, further comprising the step of, after the establishment of the one shift stage, successively establishing another shift stage, wherein the correction amount is determined for each shift stage. Is preferably determined for each hydraulic control means for establishing the following. Further, in the learning method of a hydraulic control characteristics of the automatic transmission 請 Motomeko 1, the said first hydraulic control means includes the step of driving by the reference signal
Good .

Further, in the learning method of a hydraulic control characteristics of the automatic transmission 請 Motomeko 1, it is preferable the predetermined operating state is the idling state. Further, in the learning method of a hydraulic control characteristics of the automatic transmission 請 Motomeko 1, provided with a parking range in which the automatic transmission is fixed to the output shaft, that the vehicle is in a stopped state the automatic transmission Parking Judging by being switched to the range is
Good .

Further, in the learning method of a hydraulic control characteristics of the automatic transmission 請 Motomeko 1, wherein a solenoid valve pressure control means is duty-controlled, it is preferable the driving signal is a duty control signal.

[0013]

In the learning method according to the first aspect of the present invention, for example, when one shift stage is established by two hydraulic friction engagement elements, the first pressure is supplied to the second hydraulic friction engagement element. Thus, a relatively low hydraulic pressure is supplied to the first hydraulic friction engagement element. Then, since the vehicle is stopped, the first hydraulic friction engagement element slips, and the input shaft starts rotating. Since the slip amount at this time, that is, the input shaft rotation speed is in accordance with the hydraulic pressure supplied to the first hydraulic friction engagement element, the first hydraulic control at the time when the input shaft rotation speed matches the target rotation speed is performed. If the deviation between the output signal to the means and the reference signal is calculated, the correction amount of the drive signal can be obtained according to the deviation.

Further, in the learning method according to the second aspect, since the correction amount of the drive signal to the hydraulic control means in the automatic transmission is sequentially determined, the supply hydraulic pressure to each hydraulic friction engagement element is optimized. In the learning method according to the third aspect, since one shift stage is once established and the input shaft rotation speed becomes zero, the first hydraulic friction engagement element is set to a relatively low value by slipping. The target speed and the input shaft speed quickly match.

In the learning method according to the present invention ,
Since the amount of correction of the drive signal in the automatic transmission is determined for each hydraulic control unit, the hydraulic pressure supplied to the hydraulic friction engagement element is optimized at any gear shift. Also,
In the learning method according to the present invention , after the first hydraulic pressure control unit is driven by the reference signal, adjustment is performed to make the input shaft rotation speed coincide with the target rotation speed.

In the learning method according to the present invention ,
Since the predetermined operation state is the idle operation state, the engine speed hardly fluctuates during the learning control. Further, in the learning method according to the present invention, since the stop state of the vehicle is determined based on the switching to the parking range, the output shaft speed is reliably set to 0 and the input shaft speed is set to the first hydraulic friction. It becomes equal to the slip amount of the engagement element.

Further, in the learning method according to the present invention ,
Since the hydraulic control means is a duty-controlled solenoid valve, the deviation of the hydraulic characteristics with respect to the duty control signal is uniform, and the correction amount obtained by learning can be extended.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a power plant of a passenger car to which a shift control device according to the present invention is applied. In the figure, an automatic transmission 2 is connected to the rear end of the engine 1, and the output of the engine 1 is
Is transmitted to drive wheels (not shown) via Automatic transmission 2
Is composed of a torque converter 3, a transmission main body 4, and a hydraulic controller 5, and is driven and controlled by an ECU (electronic control unit) 6. The transmission body 4 incorporates hydraulic friction engagement elements such as a hydraulic clutch and a hydraulic brake in addition to a plurality of sets of planetary gears. The hydraulic controller 5 includes an integrated hydraulic circuit and an ECU 6.
A plurality of solenoid valves (not shown) that are driven to open and close are accommodated.

On the other hand, the ECU 6 includes an input / output device (not shown), a storage device (non-volatile RAM, ROM, etc.), a central processing unit (CPU), a timer counter, etc., and detects an engine speed NE on the input side. NE 7 that detects the turbine speed NT in the torque converter 3
T sensor 8, the opening of the throttle valve not shown
Is connected.
In addition to the sensors, the ECU 6 provides the vehicle traveling speed V
Speed sensor detecting the output, the output shaft speed N of the automatic transmission 2
Various types of sensors, such as a NO sensor for detecting O, an inhibitor switch for detecting a shift position (P, N, R, D, 2, L, etc.) of the shift lever, an oil temperature sensor for detecting a hydraulic oil temperature TTF of the automatic transmission 2 Sensors and switches are connected,
They are not shown for simplicity. An MUT (multi-use tester) for performing failure diagnosis at the time of maintenance or the like can be connected to the ECU 6.

FIG. 2 shows the structure of the 1
A low reverse brake (hereinafter, L / R brake) 10 for establishing a speed stage and a reverse stage is shown by a longitudinal section.
The L / R brake 10 includes a cylinder housing 12 formed on the inner peripheral side of a transmission housing (hereinafter, housing) 11, a disk-shaped hydraulic piston 14 disposed in the cylinder chamber 12, and a housing 11. The installed brake plates 15 and each brake plate 15
The brake disc 16 and the like are alternately overlapped with each other. Brake plate 15 is housing 1
The brake disc 16 is slidably engaged with a component of the planetary gear, for example, a planetary carrier 17 via a spline in the axial direction. In the figure, reference numeral 18 denotes a pressure plate, and 19 denotes a reaction plate.

The housing 11 is provided with a port 20. When high-pressure hydraulic oil is supplied from the port 20 into the cylinder chamber 12, the hydraulic piston 14 moves to the right in the drawing. As a result, the hydraulic piston 14 is pressed via the pressure plate 18 and the brake plate 15
And the brake disc 16 are crimped, and the planetary carrier 17 is fixed to the housing 11. A return spring 21 of a disc spring type is interposed between the end face of the hydraulic piston 14 and the pressure plate 18,
When the hydraulic oil pressure drops, the return spring 2
As a result, the hydraulic piston 14 is moved back to the left in the drawing. Then, the pressing force between the brake plate 15 and the brake disc 16 is eliminated, and the two are separated from each other, so that the planetary carrier 17 can rotate freely.

FIG. 3 shows a hydraulic control circuit of the L / R brake 10. The hydraulic pump 30 is connected to the engine 1
, And generates hydraulic pressure by sucking hydraulic oil in an oil pan 32 through an oil passage 31.
The hydraulic pump 30 is connected to a first port 35 of a solenoid valve 34 serving as a hydraulic control valve via an oil passage 33, and a line whose discharge pressure is adjusted by a pressure regulating valve (not shown) in the oil passage 33. And is supplied to the first port 35. The second port 36 of the solenoid valve 34 is connected to the L / R brake 10 via an oil passage 37. When the valve body 38 in the solenoid valve 34 lifts, the line pressure is applied to the L / R brake 10. Supplied.

The valve body 38 is constantly urged toward the valve seat 40 by the return spring 39, but is sucked by the solenoid 41 by the drive current from the ECU 6 and lifted.
The duty of the solenoid valve 34 is controlled by the ECU 6 at a predetermined frequency (for example, 50 Hz). The solenoid valve 34 is provided with a drain port 43 which is always in communication with the second port 36 and is connected to the oil pan 32 via an oil passage 42. The oil passages 37 and 42 are provided with orifices 44 and 45, respectively, and the flow passage area of the orifice 44 on the oil passage 37 side is equal to the orifice 45 on the oil passage 42 side.
Is set to be larger than the flow path area. Further, the oil passage 37
An accumulator 46 is provided between the L / R brake 10 and the orifice 44 in FIG.

In this embodiment, when the driver turns on the ignition key to start the engine 1, the ECU 1
Reference numeral 6 denotes a predetermined control interval for performing learning control of the control hydraulic pressure in the procedure shown in the flowcharts of FIGS. When this control is started, the ECU 6 first executes step S1
Then, the input information from the various sensors described above is read, and then, in step S2, it is determined whether the learning condition of the hydraulic control characteristic is satisfied. In the case of the present embodiment, this determination
This is performed by the subroutine for determining whether the learning condition is satisfied or not in FIG. That is, in step S50 of the figure, it is determined whether the current shift range is the P range, whether the vehicle is stopped (ie, the current vehicle speed is 0 km / h) in step S51, and whether the automatic transmission 2 is in step S52. It is sequentially determined whether or not the hydraulic oil temperature TTF is in the range of 60 ° C. to 100 ° C. and whether or not the engine 1 is in the idling operation state in step S53. If all of these are affirmative (Yes), Step S54
To allow learning, and if any one is negative (No), learning is disabled in step S55. If these conditions are not satisfied, the vehicle may start to move during the learning control, or the hydraulic pressure or the turbine speed may not reach the predetermined values, and the learning may not be performed correctly.

If the determination in step S2 is No, the ECU 6 returns to the start without performing the learning control, and if Yes, starts counting up the timer T in step S3. Next, at step S4, it is determined again whether the learning condition is satisfied or not. If the determination is No, the learning control is stopped and the process returns to the start. Determine whether or not. If this determination is Yes, the ECU 6 first sets the transmission main body 4 to the first speed in step S6. In the case of the present embodiment, the first speed is established by engaging both the U / D clutch (under drive clutch) and the L / R brake 10 described above. In this state, since the shift range is the P range, the vehicle does not start moving, the turbine speed NT remains at 0, and only a slip in the torque converter 3 occurs. Note that the count of the timer T is 1
The reason why the first gear is not established until 0 seconds or more
This is because even in the range, a slight shift shock occurs when the first gear is established. That is, when the first gear is established immediately after the determination that learning is possible, a slight shift shock occurs immediately after the engine 1 is started, and the frequency of occurrence of this shift shock is reduced as much as possible. Learning control is not performed until seconds have elapsed.

Next, in step S7, the ECU 6 compares the drive duty ratio DL / R of the solenoid valve 34 with the reference duty ratio DNL.
/ R (20% in this embodiment). Then, FIG.
Inside, the valve body 38 that has been lifted is driven in the closing direction,
The apply pressure applied to the L / R brake 10 decreases. As a result, the hydraulic piston 14 moves to the left in FIG.
6, the turbine shaft (not shown) starts to slide. Next, in step S8, the ECU 6 again determines whether the learning condition is satisfied. If the determination is No, the ECU 6 stops the learning control and returns to the start.
In step S9, the turbine rotational speed NT is 40 rpm to 6
It is determined whether it is in the range of 0 rpm. In the transmission of this embodiment, the nominal value of the turbine speed NT is 50 rpm when the drive duty ratio DL / R is the reference duty ratio DNL / R (20%).

If the determination in step S9 is Yes,
The ECU 6 determines whether or not the value of the counter n whose initial value is 0 is 10 in step S10, and this determination is No.
If it is, 1 is added to the counter n in step S11, and the process returns to step S8 in FIG. 4 to repeat the processing. Then, the state where the turbine rotational speed NT is in the range of 40 rpm to 60 rpm continues ten times, and the determination in step S10 is Y.
If es is reached, the ECU 6 stores the current drive duty ratio DL / R (in this case, 20%) as the effective duty ratio DML / R in step S12. Here, the reason that the drive duty ratio DL / R is not actually set to the duty ratio DML / R until the counter n reaches 10 is that the drive duty ratio DL / R is reduced due to the existence of the accumulator 46 in the hydraulic control circuit. This is because the operation of the L / R brake 10 is not immediately stabilized even after the switching.

On the other hand, if the determination in step S9 is No, the ECU 6 determines in step S13 whether the current turbine rotational speed NT is smaller than 40 rpm. If this determination is Yes, the ECU 6 proceeds to step S
After the predetermined value α is subtracted from the drive duty ratio DL / R in step 14, the process returns to step S8 in FIG. 4, and the turbine drive speed NT is driven by the predetermined value α until the turbine speed NT falls within the range of 40 rpm to 60 rpm. Decrease the duty ratio DL / R. The ECU 6 determines that the turbine speed NT is 40
rpm to 60 rpm, the state continues ten times, and if the determination in step S10 becomes Yes, the current drive duty ratio DL / R (in this case,
20% or less) is stored as the effective duty ratio DML / R.

If the determination in step S13 is No, the ECU 6 determines in step S15 that the drive duty ratio D
After the predetermined value α is added to L / R, the process returns to step S8 in FIG. 4, and the turbine speed NT becomes 40 r.
The drive duty ratio DL / R is increased by a predetermined value α until the drive duty ratio DL / R falls within the range of pm to 60 rpm. Again,
The ECU 6 determines that the turbine speed NT is 40 rpm to 60 r.
pm, and the state continues 10 times, and then step S
If the determination of 10 is Yes, the current drive duty ratio DL / R (in this case, 20% or more) is stored as the actual duty ratio DML / R in step S12.

In step S12, the actual duty ratio DML / R
Is stored, the ECU 6 determines in step S16 the difference ΔD between the actual duty ratio DML / R and the reference duty ratio DNL / R.
Calculate L / R. When shifting is performed after this point, the deviation ΔDL / R is added to the drive duty ratio DL / R obtained from the control map or the like stored in the ROM, and the L / R
The solenoid valve 34 for the brake 10 is driven. As a result, even if there is an individual difference in the solenoid valve 34, the control valve, or the like, the deviation of the supply hydraulic pressure due to the difference is corrected,
The L / R brake 10 can be released or connected at a desired timing.

When the learning of the L / R brake 10 has been completed, the ECU 6 drives the solenoid valve 34 for the L / R brake 10 at 100% in step S17 in FIG. Establish. Thereafter, in step S18, the counter n is reset to 0, and in step S19, the drive duty ratio DU / D of the solenoid valve for the U / D clutch is set to the reference duty ratio DNU / D (30% in this embodiment). I do. Then, the apply pressure applied to the U / D brake decreases, and the turbine shaft (not shown) starts to slide as in the case of the L / R brake 10. Next, in step S20, the ECU 6 again determines whether or not the learning condition is satisfied. If the determination is No, the ECU 6 stops the learning control and returns to the start.
If Yes, the turbine rotational speed N is determined in step S21 of FIG.
It is determined whether T is in the range of 40 rpm to 60 rpm. In the transmission of this embodiment, the drive duty ratio D
When U / D is the reference duty ratio DNU / D (30%), the nominal value of the turbine rotational speed NT is also 50 rpm.

If the determination in step S21 is Yes, the ECU 6 determines in step S22 that the value of the counter n is 1
It is determined whether the value is 0 or not. If the determination is No, 1 is added to the counter n in step S23, and the process returns to step S20 in FIG. 6 to repeat the processing. If the state in which the turbine rotational speed NT is in the range of 40 rpm to 60 rpm continues ten times and the determination in step S22 is Yes, the ECU 6 determines in step S24 the current drive duty ratio DU / D (in this case, 20 %) Is stored as the actual duty ratio DMU / D. Here, the reason why the drive duty ratio DU / D is not actually set to the duty ratio DMU / D until the counter n reaches 10 is that the operation of the U / D clutch is not stable, as in the case of the L / R brake 10. That's why.

On the other hand, if the determination in step S21 is No, the ECU 6 determines in step S25 whether the current turbine speed NT is smaller than 40 rpm.
If the determination is Yes, the ECU 6 subtracts the predetermined value α from the drive duty ratio DU / D in step S26, and then returns to step S20 in FIG.
Until the turbine rotational speed NT falls within the range of 40 rpm to 60 rpm, the drive duty ratio DU / D is decreased by a predetermined value α. The ECU 6 determines that the turbine speed NT is 4
If the state falls within the range of 0 rpm to 60 rpm, the state continues ten times, and the determination in step S22 becomes Yes, the current drive duty ratio DU / D (in this case, 20% or less) is reduced to the real duty ratio DMU in step S24. Remember as / D.

If the determination in step S25 is No, the ECU 6 determines in step S27 that the drive duty ratio D
After the predetermined value α is added to U / D, the process returns to step S20 in FIG. 6, and the turbine rotational speed NT becomes 40 r.
The drive duty ratio DU / D is increased by a predetermined value α until the drive duty ratio DU / D is within the range of pm to 60 rpm. Again,
The ECU 6 determines that the turbine speed NT is 40 rpm to 60 r.
pm, and the state continues 10 times, and then step S
If the determination at 22 is Yes, the current drive duty ratio DU / D (in this case, 20% or more) is stored as the actual duty ratio DMU / D at step S24.

In step S24, the actual duty ratio DMU / D
Is stored, the ECU 6 determines in step S28 the deviation ΔD between the actual duty ratio DMU / D and the reference duty ratio DNU / D.
Calculate U / D. When shifting is performed after this point, the deviation ΔDU / D is added to the drive duty ratio DU / D obtained from the control map or the like stored in the ROM, and the U / D
Drive the solenoid valve for the clutch. As a result, even if there is an individual difference between the electromagnetic valve and the control valve, the deviation of the supply oil pressure due to the individual difference is corrected, and the U / D clutch can be released or engaged at a desired timing.

When learning of the U / D clutch is completed in step S28, the ECU 6 switches to normal P range control in step S29. That is, the drive duty ratio of the solenoid valve is set to 0%, and the applied pressure applied to both the L / R brake 10 and the U / D clutch is returned to 0. In the present embodiment, the above-described learning control is performed once each time the ignition key is turned on, so that even if the solenoid valve or each part of the transmission changes over time, optimal shift control is always realized. became.

Although the description of the specific embodiment has been completed above, embodiments of the present invention are not limited to this embodiment. For example,
In the description of the above embodiment, the learning is performed for the hydraulic friction engagement element for establishing the first gear, but naturally, the same learning control is sequentially performed for the reverse gear and the forward gear of the second gear or more. Alternatively, the respective hydraulic friction engagement elements may be sequentially engaged without setting the gear stage. Also,
The learning control may not be performed each time the ignition key is turned on, but may be performed once each time the battery is attached or detached, or may be performed when an MUT (multi-use tester) or the like is connected. When the MUT is used, learning is possible even if the operating state of the engine is not idle. In the above embodiment, the hydraulic control unit is a duty-driven solenoid valve, but may be a linear solenoid or the like. Further, the specific procedure of the control can be appropriately changed without departing from the gist of the present invention. For example, while engaging one hydraulic friction engagement element at full pressure, the other hydraulic friction engagement element A method of driving with a predetermined oil pressure from the beginning may be adopted.

[0038]

As described above in detail, according to the method for learning hydraulic control characteristics of the first aspect of the present invention, when the engine is in the predetermined operation state and the vehicle is in the stop state, the hydraulic control means is controlled. Driving and engaging one of the plurality of hydraulic friction engagement elements that establishes one shift speed, except for the first hydraulic friction engagement element, wherein the input shaft rotation speed of the automatic transmission is predetermined. Adjusting the supply hydraulic pressure to the first hydraulic friction engagement element by driving the first hydraulic control means so that the target rotational speed becomes the target rotational speed. Determining the deviation of the drive signal to the first hydraulic control means from the reference signal, and using this as the amount of correction of the drive signal to the first hydraulic control means. Learning of the hydraulic control characteristics reliably and promptly. , It can always be optimal shift control.

According to a second aspect of the present invention, in the learning method of the first aspect, the correction amount of the drive signal is controlled by another hydraulic control of the plurality of hydraulic control means. Since it is determined sequentially for each means, the supply hydraulic pressure to each hydraulic friction engagement element is optimized, and the shift feeling is improved. According to a third aspect of the present invention, in the learning method of the first aspect, the first hydraulic friction engagement element is configured to engage one of the plurality of shift speeds by engagement. The learning method further includes a step of once establishing the one shift speed, and after the first shift speed is achieved, the first hydraulic friction engagement element Since the step of adjusting the supply hydraulic pressure is executed, the target rotation speed set relatively low and the input shaft rotation speed quickly match, and the learning control is performed in a short time.

Further, according to the hydraulic control characteristic learning method according to the present invention , in the learning method according to the first aspect, the method further includes the step of, after the establishment of the one shift stage, sequentially establishing another shift stage. Since the amount is determined for each of the hydraulic control means for establishing each shift speed, the hydraulic pressure supplied to the hydraulic friction engagement element is optimized at any shift, and shift feeling and the like are improved.

Further, according to the method for learning hydraulic control characteristics according to the present invention , the learning method according to claim 1 further includes a step of driving the first hydraulic control means by the reference signal. The rotation speed quickly matches the target rotation speed, and the learning control is further expedited. According to the hydraulic control characteristic learning method of the present invention , in the learning method of claim 1, since the predetermined operation state is set to the idle operation state, the engine speed hardly fluctuates, and the learning control is stably performed. It is possible to do.

Further, according to the learning method of the hydraulic control characteristic according to the present invention , in the learning method of the first aspect, the stop state of the vehicle is determined based on the parking range. While the input shaft speed becomes equal to the slip amount of the first hydraulic friction engagement element,
Creep of the vehicle at the time of establishing one shift speed is prevented, and learning control can be performed safely.

According to the hydraulic control characteristic learning method of the present invention , in the learning method of claim 1, the hydraulic control means is a duty-controlled solenoid valve and the drive signal is a duty control signal. The deviation of the hydraulic pressure characteristic with respect to the signal becomes uniform, and the correction amount obtained by learning can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a power train to which a shift control device according to the present invention is applied.

FIG. 2 is a longitudinal sectional view showing a structure of an L / R brake.

FIG. 3 is a diagram showing a hydraulic circuit for operating the L / R brake of FIG. 2;

FIG. 4 is a flowchart showing a learning control process according to the embodiment.

FIG. 5 is a flowchart showing a process of learning control in the embodiment.

FIG. 6 is a flowchart showing a process of learning control in the embodiment.

FIG. 7 is a flowchart showing a process of learning control in the embodiment.

FIG. 8 is a flowchart showing a subroutine for determining whether a learning condition is satisfied.

FIG. 9 is a graph showing a relationship between a drive duty ratio of a solenoid valve and a supply oil pressure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 5 Hydraulic controller 6 ECU 8 NT sensor 10 L / R brake 14 Hydraulic piston 30 Hydraulic pump 34 Solenoid valve

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-151063 (JP, A) JP-A-63-170136 (JP, A) JP-A-62-278349 (JP, A) 296333 (JP, A) JP-A-2-159456 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (3)

(57) [Claims] 1. A plurality of hydraulic friction engagement elements interposed between an engine of an automobile and drive wheels via a fluid coupling and achieving a plurality of shift speeds by combination, based on a drive signal from a control device. In a method of learning hydraulic control characteristics of an automatic transmission comprising a plurality of hydraulic control means for controlling a hydraulic pressure supplied to these hydraulic friction engagement elements, when the engine is in a predetermined operating state and the vehicle is in a stopped state, The first hydraulic control means is driven so that the input shaft rotation speed of the automatic transmission becomes a predetermined target rotation speed, and the first hydraulic control means is connected to a first hydraulic friction engagement element of the plurality of hydraulic friction engagement elements. Adjusting the supply hydraulic pressure of the motor; calculating a deviation of a drive signal from the reference signal to the first hydraulic pressure control unit when the input shaft rotation speed matches the target rotation speed; To the first hydraulic control means. Learning method of a hydraulic control characteristics of an automatic transmission, which comprises a step of obtaining a correction amount of the drive signal. 2. The hydraulic control characteristic of the automatic transmission according to claim 1, wherein the correction amount of the drive signal is sequentially determined for each of the other hydraulic control units of the plurality of hydraulic control units. Learning method. 3. The learning method according to claim 1, wherein the first hydraulic friction engagement element is involved in establishing one of the plurality of shift speeds by engagement thereof. 2. The automatic transmission according to claim 1, further comprising a step of once establishing a shift speed, and after executing said one shift speed, performing a step of adjusting a hydraulic pressure supplied to said first hydraulic friction engagement element. A method for learning the hydraulic control characteristics of the transmission.