JP3927370B2 - Hydraulic control device for automatic transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to hydraulic control for discharging air mixed in a hydraulic circuit.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a hydraulic control device for an automatic transmission that controls the engagement / release of a friction engagement element with a hydraulic pressure, a friction engagement element (clutch or brake) to be released from the request of the gear stage at that time during non-shift On the other hand, a configuration is known in which air mixed in the hydraulic circuit is discharged by periodically supplying hydraulic pressure within a range in which the piston does not stroke (see Japanese Patent Laid-Open No. 10-169764).
[0003]
[Problems to be solved by the invention]
By the way, in the air discharge control described above, the hydraulic pressure is supplied to the friction engagement element to be released from the request of the gear stage at that time. The oil supplied to the frictional engagement element that transmits torque may be insufficient and slippage may occur.
[0004]
The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to avoid a shortage of the amount of oil supplied to the friction engagement element to be originally engaged due to air discharge control.
[0005]
[Means for Solving the Problems]
Therefore, according to the first aspect of the present invention, the hydraulic pressure is forcibly supplied to the friction engagement element to be released at the current gear stage during non-shifting, thereby automatically discharging air mixed in the hydraulic circuit. In the hydraulic control device of the transmission, the forced hydraulic pressure supply to the friction engagement element to be released is configured to be repeated periodically, and when the periodic hydraulic pressure supply is performed, The time ratio of the hydraulic pressure supply state is set to be smaller as the oil amount balance of the oil is smaller .
[0007]
According to this configuration, when the amount of oil is insufficient, that is, the amount of oil that can be supplied to the release friction engagement element that discharges air after securing the amount of oil supplied to the original engagement friction engagement element is small. The time ratio (supply time per cycle) of the hydraulic pressure supply state is reduced as time passes, and the amount of oil supplied to the release friction engagement element that discharges air is reduced.
[0008]
In the invention described in claim 2, the control cycle is shortened as the amount of oil is insufficient. According to this configuration, if the control cycle is shortened, the duration of the hydraulic supply state is shortened even if the time ratio of the hydraulic supply state is the same. If the duration is short, the effect of the response delay of the hydraulic supply increases and the air is actually discharged. Therefore, the amount of oil supplied to the release friction engagement element is reduced.
[0009]
According to a third aspect of the present invention, the oil amount balance is determined according to the discharge amount of an oil pump that supplies oil to the automatic transmission. According to such a configuration, the smaller the discharge amount of the oil pump, the smaller the margin for supplying hydraulic pressure to the frictional engagement element that should be released, so the smaller the discharge amount, the less the oil amount. to decide.
[0010]
In the invention according to claim 4 , the oil pump is driven by an engine combined with an automatic transmission, and the discharge amount of the oil pump is estimated based on the rotational speed of the engine. According to this configuration, the rotational speed of the engine and the rotational speed of the oil pump are in a fixed relationship, and the discharge amount changes in accordance with the rotational speed of the oil pump. Presumed.
[0011]
In the fifth aspect of the invention, the oil amount balance is determined according to the required supply amount of oil to the friction engagement element to be fastened at the current shift speed. According to such a configuration, even if the oil pump discharge amount is the same, when there is a large amount of oil that needs to be supplied to the friction engagement element that should be fastened, the amount of oil that can be supplied for air discharge relatively Therefore, the amount of oil that can be supplied for air discharge (oil amount balance) can be determined based on the required supply amount of oil to the friction engagement element that should be originally engaged.
[0012]
According to the sixth aspect of the present invention, the required supply amount of oil to the friction engagement element to be fastened is determined according to the load of the engine combined with the automatic transmission. According to such a configuration, the hydraulic pressure (in other words, the torque capacity) required for the friction engagement element to be originally engaged is required to be higher as the input torque is larger, and the input torque is applied to the engine load. Therefore, the required supply amount of oil to the friction engagement element to be engaged at the current shift stage is determined from the engine load, and therefore the amount of oil that can be supplied for air discharge (oil amount balance) is determined. I can judge.
[0013]
【The invention's effect】
According to the first and second aspects of the invention, the amount of oil supplied to the original frictional engagement element to be fastened is secured and air is discharged from the frictional engagement element to be released. The amount of oil supplied to the engine can be controlled, and as much oil as possible is supplied for air discharge while avoiding the occurrence of slipping due to insufficient oil amount of the friction engagement element that should be fastened. This has the effect that the air can be discharged efficiently.
[0014]
According to the third aspect of the invention, there is an effect that the amount of oil (oil amount balance) that can be supplied for air discharge can be accurately determined from the discharge amount of the oil pump. According to the fourth aspect of the invention, there is an effect that it is possible to easily determine the oil amount balance based on the discharge amount of the oil pump. According to the fifth aspect of the present invention, there is an effect that it is possible to accurately determine the amount of oil that can be relatively supplied for air discharge from the amount of oil that needs to be supplied to the original frictional engagement element to be fastened. .
[0015]
According to the sixth aspect of the present invention, the amount of oil that needs to be supplied to the original frictional engagement element to be fastened is judged from the engine load, and the amount of oil that can be supplied for air discharge is relatively easy. There is an effect that it can be judged.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 shows a drive system of a vehicle in an embodiment. An automatic transmission 3 is connected to an output shaft of an engine 1 via a torque converter 2, and is illustrated by an output shaft of the automatic transmission 3. The drive wheels of the vehicle that do not rotate are driven to rotate.
[0017]
FIG. 2 is a skeleton showing the speed change mechanism portion of the automatic transmission 3.
The transmission mechanism section includes two sets of planetary gears G1, G2, three sets of multi-plate clutches (high clutch H / C, reverse clutch R / C, low clutch L / C), one set of brake bands 2 & 4 / B, One set of multi-plate brakes (low & reverse brake L & R / B) and one set of one-way clutch L / OWC.
[0018]
The two sets of planetary gears G1 and G2 are simple planetary gears composed of sun gears S1 and S2, ring gears r1 and r2, and carriers c1 and c2, respectively.
The sun gear S1 of the planetary gear set G1 is configured to be connectable to the input shaft IN by a reverse clutch R / C, and is configured to be fixed by a brake band 2 & 4 / B.
[0019]
The sun gear S2 of the planetary gear set G2 is directly connected to the input shaft IN.
The carrier c1 of the planetary gear set G1 is configured to be connectable to the input shaft IN by a high clutch H / C, while the ring gear r2 of the planetary gear set G2 is a carrier of the planetary gear set G1 by a low clutch L / C. The carrier c1 of the planetary gear set G1 can be fixed by a low & reverse brake L & R / B.
[0020]
A ring gear r1 of the planetary gear set G1 and a carrier c2 of the planetary gear set G2 are directly and integrally connected to the output shaft OUT.
In FIG. 2, reference numeral 21 denotes an oil pump (hydraulic pump) that is driven by the engine 1 and supplies hydraulic oil to the automatic transmission.
In the speed change mechanism having the above-described configuration, forward 1st to 4th speeds and reverse R are realized by a combination of engagement / release states of the respective clutches and brakes (friction engagement elements) as shown in FIG.
[0021]
In FIG. 3, the circles indicate the engaged state, and the parts not marked with the symbol indicate that they are in the released state. In particular, the engaged state indicated by the black circle of the low & reverse brake L & R / B at the first speed. Indicates fastening in only one range.
The above engagement / release logic of the friction engagement element is realized by a combination of ON / OFF of the shift solenoid (A) 5 and the shift solenoid (B) 6 inserted in the control valve 4 for shift control shown in FIG. (See FIG. 4).
[0022]
A line pressure solenoid 7 is inserted into the control valve 4, and the line pressure of the control valve 4 is controlled by the line pressure solenoid 7.
The shift solenoid (A) 5, the shift solenoid (B) 6 and the line pressure solenoid 7 are controlled by an A / T controller 11.
The A / T controller 11 includes an ATF temperature sensor 12 that detects the temperature of an ATF (automatic transmission fluid (hereinafter referred to as ATF)), and a throttle valve that throttles the intake of the engine 1 in conjunction with an accelerator pedal (not shown). 8, a throttle opening sensor 13 for detecting an opening degree TVO, a vehicle speed sensor 14 for a vehicle traveling speed VSP, an engine rotation sensor 15 for detecting a rotational speed Ne of the engine 1, and a range position selected by operating a shift knob. Detection signals are input from the inhibitor switch 16, the water temperature sensor 17 for detecting the coolant temperature of the engine 1, the outside air temperature sensor 18, and the like.
[0023]
The A / T controller 11 performs normal shift control based on the above various detection signals, while executing the control program shown in the flowchart of FIG. Control is performed to discharge air (bubbles) mixed in the circuit.
Details of the air discharge control will be described below with reference to the flowchart of FIG.
[0024]
In step S1, it is determined whether or not an air discharge control execution permission condition is satisfied.
As the execution permission condition, for example, immediately after switching from the first N range (neutral range) to the D range (drive range) after the ignition switch is turned on, there is no shift request and the first speed is stabilized. It is determined whether or not it is in a state.
[0025]
If it is determined that the execution permission condition as described above is satisfied, the process proceeds to step S2.
In step S2, the engine speed Ne is read.
The oil pump 21 in the present embodiment is driven by the engine 1 and the discharge amount changes according to the engine rotation speed Ne. Therefore, the engine rotation speed Ne is a parameter indicating the discharge amount of the oil pump 21.
[0026]
In step S3, a control duty ratio corresponding to the engine speed Ne at that time is searched by referring to a table in which the control duty ratio of the air discharge control is stored in advance according to the engine speed Ne.
In the present embodiment, as will be described later, the forced hydraulic pressure is supplied to the friction engagement element to be released at the gear stage at that time, and the air is discharged by periodically repeating the operation. The control duty ratio is a time ratio for supplying hydraulic pressure per cycle in the periodic hydraulic pressure supply.
[0027]
Here, the control duty ratio is set to increase as the engine rotational speed Ne increases and the discharge amount of the oil pump 21 increases.
When the discharge amount of the oil pump 21 is large, there is a large margin obtained by excluding the amount of oil necessary for the friction engagement element to be fastened from the discharge amount, and this margin can be used for air discharge control. Therefore, based on the oil amount balance, the control duty ratio is increased as the engine rotational speed Ne is higher and the discharge amount of the oil pump 21 is larger.
[0028]
In step S4, the hydraulic pressure is periodically supplied to the frictional engagement element to be released at the current gear position based on the control duty ratio.
Specifically, assuming that the air discharge control is performed in the first speed state, both the shift solenoid (A) 5 and the shift solenoid (B) 6 are turned off at a predetermined period for a time corresponding to the control duty ratio. Switching (see FIG. 6).
[0029]
In the first speed, both the shift solenoid (A) 5 and the shift solenoid (B) 6 are controlled to be in the ON state, the high clutch H / C is released, and the low clutch L / C is engaged. The state where both the shift solenoid (A) 5 and the shift solenoid (B) 6 are OFF corresponds to the state of the third speed, and at the third speed, the low clutch L / C and the high clutch H / C are engaged (FIGS. 3 and 4). reference).
[0030]
Accordingly, by periodically switching both the shift solenoid (A) 5 and the shift solenoid (B) 6 OFF, the hydraulic pressure is periodically supplied to the high clutch H / C to be released at the first speed. As a result, air mixed in the hydraulic circuit of the high clutch H / C is discharged by supplying the hydraulic pressure.
Here, when the discharge amount of the oil pump 21 is small, a relatively small value is set as the control duty ratio (see “when the oil amount balance is insufficient”), so that the high clutch H / C is used for air discharge. The amount of oil supplied to the engine is limited, and it is prevented that the oil supplied to the low clutch L / C to be originally engaged is insufficient.
[0031]
On the other hand, when the discharge amount of the oil pump 21 is large, a relatively large value is set as the control duty ratio (see “when the oil amount balance is not insufficient”), so that the supply to the low clutch L / C. While ensuring the amount of oil to be supplied, a large amount of oil is supplied to the high clutch H / C to efficiently discharge air.
The air discharge control is stopped when the cumulative execution time exceeds a predetermined time, but the amount of oil supplied to the high clutch H / C changes within the same time depending on the control duty ratio. It is preferable to make a correction according to the control duty ratio and compare it with a predetermined time.
[0032]
In the above embodiment, the control duty ratio (time ratio of the hydraulic pressure supply state) is changed in accordance with the engine rotational speed Ne correlated with the discharge amount of the oil pump 21, but instead of the control duty ratio, the control duty ratio is controlled. It is good also as a structure which changes a period (control frequency).
In the flowchart of FIG. 7, steps S11 and S12 perform the same processing as steps S1 and S2.
[0033]
In step S13, the control cycle corresponding to the engine rotation speed Ne at that time is searched by referring to a table in which the control cycle of air discharge control is stored in advance according to the engine rotation speed Ne.
Here, the control cycle becomes longer as the engine rotational speed Ne is higher and the discharge amount of the oil pump 21 is larger.
[0034]
When the discharge amount of the oil pump 21 is large, there is a large margin that can be used as the air discharge amount. Therefore, based on the oil amount balance, the control cycle is increased as the engine rotational speed Ne is higher and the discharge amount of the oil pump 21 is larger. Lengthen.
If the control cycle is short, the duration of the hydraulic supply state will be short even if the time ratio of the hydraulic supply state is the same, and if the duration is short, the effect of the response delay of the hydraulic supply will be large and the friction will actually be released for air discharge The amount of oil supplied to the engagement element is reduced.
[0035]
On the contrary, if the control cycle is long, the duration of the hydraulic pressure supply state becomes long and the influence of the delay in response of the hydraulic pressure supply becomes small, and the amount of oil actually supplied to the release friction engagement element for air discharge is large. Become.
In step S14, the shift solenoid (A) 5 and the shift solenoid (B) 6 are periodically switched OFF at a constant control duty ratio according to the control cycle set in step S13.
[0036]
Here, when the discharge amount of the oil pump 21 is small, a relatively short time (high frequency) is set as the control cycle (see “when the oil amount balance is insufficient”), so that the high clutch is used for air discharge. The amount of oil supplied to the H / C is limited, and it is prevented that the oil supplied to the low clutch L / C to be originally engaged is insufficient.
[0037]
On the other hand, when the discharge amount of the oil pump 21 is large, a relatively long time (low frequency) is set as the control cycle (see “when oil amount balance is not insufficient”), so that the low clutch L / C is On the other hand, while ensuring the amount of oil to be supplied, a large amount of oil is supplied to the high clutch H / C to efficiently discharge air.
The change in the time ratio of the hydraulic pressure supply state and the change in the control cycle are combined, and when the engine rotation speed Ne is low and the discharge amount of the oil pump 21 is small, the time ratio is reduced and the control cycle is shortened. On the other hand, when the engine rotational speed Ne is high and the discharge amount of the oil pump 21 is large, the time ratio may be increased and the control cycle may be lengthened.
[0038]
Further, in the above embodiment, the oil amount balance is determined based on the discharge amount (engine rotational speed Ne) of the oil pump 21, but even if the discharge amount of the oil pump 21 is the same, for example, Since the amount of oil that needs to be supplied to the engagement friction engagement element (low clutch L / C) changes the amount that can be supplied to the release friction engagement element (high clutch H / C) for air discharge. The oil amount balance is determined based on the amount of oil that needs to be supplied to the friction engagement element (low clutch L / C), and the time ratio and / or control cycle of the hydraulic pressure supply state in the air discharge control is changed. Also good.
[0039]
The flowchart of FIG. 9 shows an embodiment in which the oil amount balance is determined based on the amount of oil that needs to be supplied to the engagement friction engagement element (low clutch L / C).
In step S21, as in step S1, the air discharge control permission condition is determined. If the permission condition is satisfied, the process proceeds to step S22.
In step S22, the throttle opening TVO is read.
[0040]
In step S23, an engine load idling state where the throttle opening TVO is equal to or smaller than a predetermined value and an engine load non-idle state exceeding the predetermined value are determined, and the time ratio of the hydraulic pressure supply state is determined based on the determination result. To do.
Specifically, in the engine load idle state where the throttle opening TVO is equal to or less than a predetermined value, the time ratio of the hydraulic pressure supply state is lengthened, and in the engine load non-idle state where the throttle opening TVO exceeds the predetermined value, The time ratio of the hydraulic pressure supply state is shortened.
[0041]
When the engine load is in a non-idle state and the input torque of the automatic transmission 3 is relatively large, in order to transmit the input torque, there is a high demand for the torque capacity of the friction engagement element to be fastened at that speed. Therefore, in order to secure a high torque capacity, it is necessary to supply a large amount of oil.
That is, the state where the throttle opening TVO exceeds a predetermined value indicates that the required amount of oil supplied to the frictional engagement element to be engaged at the gear stage at that time is large, and relatively at the gear stage at that time. Less oil can be supplied to the frictional engagement elements to be released.
[0042]
Therefore, in the non-idle state of the engine load where the throttle opening TVO exceeds a predetermined value, the time ratio of the hydraulic pressure supply state is shortened to limit the amount of oil used for air discharge, and the gear stage at that time The required supply amount of oil to the friction engagement element to be fastened is ensured.
In the case where an idle switch that is turned ON when the throttle valve is fully closed is provided, the time ratio of the hydraulic pressure supply state can be set based on ON / OFF of the idle switch.
[0043]
Further, the time ratio may be gradually changed according to the throttle opening TVO.
In step S24, the shift solenoid (A) 5 and the shift solenoid (B) 6 are periodically switched OFF based on the time ratio of the hydraulic pressure supply state set in step S23.
[0044]
Note that, as described above, even in the configuration in which the oil amount balance is determined based on the engine load indicating the required supply amount of oil to the friction engagement element to be fastened at the gear stage at that time, instead of the time ratio, The control cycle can be changed, and an embodiment having such a configuration is shown in the flowchart of FIG.
In the flowchart of FIG. 10, in step S33, in the engine load idle state where the throttle opening TVO is equal to or less than a predetermined value, the control cycle is lengthened, and in the engine load non-idle state where the throttle opening TVO exceeds the predetermined value. The control cycle is shortened.
[0045]
In step S34, the shift solenoid (A) 5 and the shift solenoid (B) 6 are periodically switched OFF at a constant duty ratio according to the set control cycle.
In this case as well, the change of the time ratio and the change of the control cycle may be combined.
[0046]
Further, in the above description, the engine load (the throttle opening indicating the engine load) is used as a parameter indicating the required supply amount of oil to the friction engagement element to be engaged at the gear stage at that time. When individually controlling the oil pressure of the elements, it is possible to determine the oil amount balance based on the command oil pressure for the friction engagement element to be fastened at the gear stage at that time.
[0047]
Further, the oil amount balance is determined by combining the determination of the discharge amount of the oil pump 21 based on the engine rotational speed Ne and the determination of the required supply amount of oil to the engagement friction engagement element based on the engine load or the indicated hydraulic pressure. Anyway.
That is, when the discharge amount of the oil pump 21 is large, the time ratio and / or the control cycle is lengthened, but when the required supply amount of oil to the engagement friction engagement element at that time is large (the engine load is large and the command hydraulic pressure is large). Time), the time ratio and / or control cycle set based on the discharge amount is corrected to decrease.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a vehicle drive system in an embodiment.
FIG. 2 is a skeleton diagram showing a speed change mechanism in the embodiment.
FIG. 3 is a diagram showing a combination of engagement states of frictional engagement elements at gear positions in the embodiment.
FIG. 4 is a diagram showing a combination of ON / OFF of shift solenoids A and B at each gear position in the embodiment.
FIG. 5 is a flowchart showing a first embodiment of air discharge control.
FIG. 6 is a time chart showing a correlation between a control duty ratio and an oil amount balance.
FIG. 7 is a flowchart showing a second embodiment of air discharge control.
FIG. 8 is a time chart showing a correlation between a control cycle and an oil amount balance.
FIG. 9 is a flowchart showing a third embodiment of air discharge control.
FIG. 10 is a flowchart showing a fourth embodiment of air discharge control.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Torque converter 3 ... Automatic transmission 4 ... Control valve 5 ... Shift solenoid (A)
6. Shift solenoid (B)
7 ... Line pressure solenoid 11 ... A / T controller 12 ... ATF temperature sensor 13 ... Throttle opening sensor 14 ... Vehicle speed sensor 15 ... Engine rotation sensor 16 ... Inhibitor switch 17 ... Water temperature sensor 18 ... Outside air temperature sensor 21 ... Oil pump G1, G2 ... Planetary gear H / C ... High clutch R / C ... Reverse clutch L / C ... Low clutch 2 & 4 / B ... Brake band L & R / B ... Low & reverse brake L / OWC ... One-way clutch

Claims (6)

In a hydraulic control device for an automatic transmission that discharges air mixed in a hydraulic circuit by forcibly supplying hydraulic pressure to a friction engagement element to be released at a current shift stage during non-shifting, The forced hydraulic pressure supply to the friction engagement element to be released is configured to be repeated periodically, and when the periodic hydraulic pressure supply is performed, the oil amount balance at that time is insufficient. A hydraulic control device for an automatic transmission, characterized in that the time ratio of the hydraulic pressure supply state is reduced as the time elapses . In a hydraulic control device for an automatic transmission that discharges air mixed in a hydraulic circuit by forcibly supplying hydraulic pressure to a friction engagement element to be released at a current shift stage during non-shifting, The forced hydraulic pressure supply to the friction engagement element to be released is configured to be repeated periodically, and when the periodic hydraulic pressure supply is performed, the oil amount balance at that time is insufficient. A hydraulic control device for an automatic transmission, characterized in that the control cycle is shortened as the time elapses . The hydraulic control device for an automatic transmission according to claim 1 or 2, wherein an oil balance is determined according to a discharge amount of an oil pump that supplies oil to the automatic transmission. 4. The automatic transmission according to claim 3 , wherein the oil pump is driven by an engine combined with the automatic transmission, and a discharge amount of the oil pump is estimated based on a rotation speed of the engine. Hydraulic control device for the machine. 3. The hydraulic control device for an automatic transmission according to claim 1, wherein an oil amount balance is determined according to a required supply amount of oil to a friction engagement element to be engaged at a current gear stage. 6. The hydraulic control device for an automatic transmission according to claim 5 , wherein the required supply amount of oil to the friction engagement element to be fastened is determined according to an engine load combined with the automatic transmission.

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