JP4760308B2 - Hydraulic control device for automatic transmission - Google Patents

Description

  The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to hydraulic control when an accelerator is returned to a driven state during a power-on upshift in a driven state.

The present invention relates to an automatic transmission that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of hydraulic friction engagement devices, and increasing the hydraulic oil pressure supplied to a predetermined friction engagement device. When the upshift is executed, if the accelerator is returned to the driven state during the power-on upshift in the driving state and the driven state is changed to the driven state, the capacity of the friction engagement device is set to the input torque of the automatic transmission. Become excessive. For this reason, in the apparatus described in Patent Document 1, changes in the input torque of the automatic transmission are checked one by one during the upshift, and when there is a change in the input torque, the hydraulic oil that is immediately supplied to the friction engagement device It is proposed that the hydraulic pressure command value is changed to a value corresponding to the input torque (see step 57 in FIG. 5) to prevent the friction engagement device from being excessive or insufficient with respect to the change in the input torque. Yes.
JP 2000-110929 A

By the way, when the accelerator is returned during the power-on upshift and switched to the driven power-off upshift, conventionally, the power-on-side hydraulic command value is immediately switched to the power-off-side hydraulic command value. For example, a change pattern of the oil pressure command value during a dashed line power ON in the column of hydraulic pressure instruction value of FIG. 11, the broken line is the change pattern of the oil pressure command value at the time of power OFF, the power OFF upshift at time t ₃ When switched, as indicated by the white arrow, the power ON side hydraulic pressure command value indicated by the alternate long and short dash line is immediately switched to the broken power OFF side hydraulic pressure command value.

  Here, conventionally, the hydraulic pressure actually supplied to the friction engagement device is controlled by controlling the balance valve such as the control valve in accordance with the output hydraulic pressure such as the solenoid valve. Although the oil pressure control is difficult, especially when the oil pressure changes greatly, the actual engagement oil pressure is gentle even if there is a difference in oil pressure between the power ON side oil pressure command value and the power OFF side oil pressure command value. The output torque also changes gently along with this, so that the driver did not feel uncomfortable.

  However, in recent years, direct pressure control that supplies the output hydraulic pressure as it is to the friction engagement device has been performed using a large-capacity linear solenoid valve, and the response to changes in hydraulic pressure of the friction engagement device has been dramatically improved. did. For this reason, when switching from the power ON side hydraulic pressure command value to the power OFF side hydraulic pressure command value as described above, if the hydraulic pressure difference between them is large, the hydraulic pressure is suddenly released, so that the output torque of FIG. As shown in the column, the output torque suddenly decreased and a shock due to torque loss occurred, causing the driver to feel uncomfortable.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to change the power ON side hydraulic pressure command value when the accelerator is returned to the driven state during the power ON upshift in the driving state. It is intended to prevent a shock due to a sudden torque loss when switching from the hydraulic pressure command value to the power OFF side.

In order to achieve this object, the first invention relates to (a) an automatic transmission that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of hydraulic friction engagement devices, (b) When the hydraulic pressure of the hydraulic fluid supplied to a predetermined friction engagement device is increased and an upshift is executed, the accelerator is returned during the power-on upshift in the driving state and changed to the driven state. Is an automatic transmission having hydraulic command value switching means for switching a hydraulic command value supplied to the friction engagement device from a power ON side hydraulic command value in a driving state to a power OFF side hydraulic command value in a driven state. in the hydraulic control device, (c) the power oN hydraulic pressure command value and the power OFF hydraulic pressure command value, respectively parallel with the shift command of the power oN upshift in a predetermined change pattern Allowed to reduction, power ON, and so is properly selected used hydraulic control in accordance with the OFF, (d) the hydraulic pressure command value switching means, said power OFF side hydraulic from the power ON hydraulic pressure command value When switching to the command value, the power ON side hydraulic pressure command value is gradually reduced with a predetermined gradient, and when the power OFF side hydraulic pressure command value is reached , switching to hydraulic control using the power OFF side hydraulic pressure command value is performed. Features.

  According to such a hydraulic control device for an automatic transmission, when switching from the power ON side hydraulic command value to the power OFF side hydraulic command value, the friction command device is used to gradually reduce the hydraulic command value with a predetermined gradient. The hydraulic pressure of the hydraulic oil supplied to is prevented from abruptly decreasing, and a shock due to torque loss is suppressed.

  The present invention is preferably applied to an automatic transmission for a vehicle, and can be applied to various automatic transmissions for vehicles such as an engine-driven vehicle that generates a driving force by combustion of fuel and an electric vehicle that runs by an electric motor. . As the automatic transmission, for example, various automatic transmissions such as a planetary gear type and a parallel shaft type in which a plurality of gear stages are established in accordance with operating states of a plurality of clutches and brakes are used.

  The friction engagement device is a single-plate or multi-plate clutch or brake that is engaged by a hydraulic actuator such as a hydraulic cylinder, a belt-type brake, or the like. Direct pressure control that is supplied as it is and engaged by the output hydraulic pressure is preferably employed. According to such direct pressure control, it is possible to control the hydraulic pressure of the actual friction engagement device with high responsiveness (follow-up performance) according to the hydraulic pressure command value, and the hydraulic pressure command value that can be gradually decreased at a predetermined gradient. The actual oil pressure is reduced with high follow-up performance, and the slope of the oil pressure command value is appropriately determined so that the torque change intended by the driver occurs while preventing shock due to sudden torque loss. Can do.

  The gradient of the hydraulic pressure command value when switching from the power ON side hydraulic pressure command value to the power OFF side hydraulic pressure command value may be set in advance, but for each friction engagement device to be engaged or from which gear stage It may be set for each gear type of upshift to which gear stage, and further change speed of accelerator operation amount at the time of vehicle speed, oil temperature (hydraulic oil viscosity), or power ON → OFF change Also, it may be set in consideration of the vehicle state, the driving state, etc., such as the presence / absence of a brake operation and the progress degree of the power ON upshift. The power ON side hydraulic pressure command value may be changed with a constant gradient from the power OFF side hydraulic pressure command value, but various modes are possible such as changing the gradient halfway or continuously. .

  In addition, after the friction engagement device has torque and the inertia phase in which the input shaft rotation speed changes starts, when the hydraulic pressure of the friction engagement device decreases and is released, neutral (power transmission interruption) Since there is a possibility that a shock will occur due to torque loss, the hydraulic pressure command value is changed with a predetermined gradient only when the power OFF upshift is changed after the inertia phase starts, and before the inertia phase starts. May be changed at once from the power ON side hydraulic pressure command value to the power OFF side hydraulic pressure command value. Regardless of whether the inertia phase has started or not, the hydraulic pressure command value can always be changed with a predetermined gradient.

  In order to enable switching from the power ON side hydraulic pressure command value to the power OFF side hydraulic pressure command value at any time, the power ON side hydraulic pressure command value and the power OFF side hydraulic pressure command value are in parallel with the shift command. Thus, it is changed according to a predetermined change pattern, and is appropriately selected according to the power ON / OFF and used for hydraulic control.

  The present invention is preferably applied to a case where the gear stage is automatically switched in accordance with a predetermined shift condition (such as a map) using the vehicle speed, the throttle valve opening, and the like as parameters. The present invention can also be applied to a case where a plurality of shift ranges having different ranges and the gear stage themselves are switched by manual operation and shift control is performed accordingly. The gradient of the hydraulic pressure command value when the power is switched from ON to OFF can be changed depending on whether automatic shift or manual shift is performed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a skeleton diagram of a horizontally-mounted vehicle drive device such as an FF (front engine / front drive) vehicle. An output of an engine 10 constituted by an internal combustion engine such as a gasoline engine includes a torque converter 12, Via an automatic transmission 14, a differential gear device (not shown) is transmitted to drive wheels (front wheels). The engine 10 is a power source for vehicle travel, and the torque converter 12 is a fluid coupling.

  The automatic transmission 14 includes a first transmission unit 22 mainly composed of a single pinion type first planetary gear unit 20, a single pinion type second planetary gear unit 26, and a double pinion type third planetary gear unit. The second transmission unit 30, which is mainly composed of 28, is provided on the coaxial line, and the rotation of the input shaft 32 is shifted and output from the output gear 34. The input shaft 32 corresponds to the input member, and in this embodiment is the turbine shaft of the torque converter 12, and the output gear 34 corresponds to the output member, and rotates the left and right drive wheels via the differential gear device. To drive. The automatic transmission 14 is substantially symmetrical with respect to the center line, and the lower half of the center line is omitted in FIG.

  The first planetary gear unit 20 constituting the first transmission unit 22 includes three rotation elements, that is, a sun gear S1, a carrier CA1, and a ring gear R1, and the sun gear S1 is connected to the input shaft 32 to be rotationally driven. At the same time, the ring gear R1 is fixed to the case 36 through the third brake B3 so as not to rotate, whereby the carrier CA1 is decelerated and rotated with respect to the input shaft 32 as an intermediate output member. Further, the second planetary gear device 26 and the third planetary gear device 28 constituting the second transmission unit 30 are partially connected to each other to constitute four rotating elements RM1 to RM4. Specifically, the first rotating element RM1 is constituted by the sun gear S3 of the third planetary gear device 28, and the ring gear R2 of the second planetary gear device 26 and the ring gear R3 of the third planetary gear device 28 are connected to each other to perform the second rotation. The element RM2 is configured, and the carrier CA2 of the second planetary gear unit 26 and the carrier CA3 of the third planetary gear unit 28 are coupled to each other to configure the third rotating element RM3. A four-rotation element RM4 is configured. In the second planetary gear device 26 and the third planetary gear device 28, the carriers CA2 and CA3 are constituted by a common member, the ring gears R2 and R3 are constituted by a common member, and the second The pinion gear of the planetary gear device 26 is a Ravigneaux type planetary gear train that also serves as the second pinion gear of the third planetary gear device 28.

  The first rotating element RM1 (sun gear S3) is selectively connected to the case 36 by the first brake B1 and stopped rotating, and the second rotating element RM2 (ring gears R2, R3) is selectively selected by the second brake B2. The fourth rotation element RM4 (sun gear S2) is selectively connected to the input shaft 32 via the first clutch C1, and the second rotation element RM2 (ring gears R2, R3) is connected to the case 36 and stopped. Is selectively coupled to the input shaft 32 via the second clutch C2, and the first rotating element RM1 (sun gear S3) is integrally coupled to the carrier CA1 of the first planetary gear device 20 as an intermediate output member, The third rotation element RM3 (carriers CA2, CA3) is integrally connected to the output gear 34 to output rotation.

The clutches C1, C2 and the brakes B1, B2, B3 (hereinafter simply referred to as the clutch C and the brake B unless otherwise distinguished) are hydraulic friction members that are engaged and controlled by a hydraulic actuator such as a multi-plate clutch or a band brake. 2 is engaged and released as shown in FIG. 2 by switching the hydraulic circuit by excitation or non-excitation of the linear solenoid valves SL1 to SL5 of the hydraulic control circuit 98 (see FIG. 3) or a manual valve (not shown). The state is switched, and the six forward gears and the reverse one gear are established according to the operation position (position) of the shift lever 72 (see FIG. 3). “1st” to “6th” in FIG. 2 mean the first to sixth gears for forward travel, and “Rev” is the reverse gear for the gear ratio (= input shaft rotation). (Speed N _IN / output shaft rotational speed N _OUT ) is appropriately determined by the gear ratios ρ1, ρ2, and ρ3 of the first planetary gear device 20, the second planetary gear device 26, and the third planetary gear device 28. “◯” in FIG. 2 means engagement, and a blank means release.

  The shift lever 72 is, for example, in accordance with the shift pattern shown in FIG. 4, a parking position “P”, a reverse travel position “R”, a neutral position “N”, a forward travel position “D”, “4”, “3”, “2” ”And“ L ”, and in the“ P ”and“ N ”positions, neutral is established to cut off the power transmission. However, in the“ P ”position, a mechanical parking mechanism (not shown) is used to mechanically The rotation of the drive wheel is prevented.

FIG. 3 is a block diagram for explaining a control system provided in the vehicle for controlling the engine 10 and the automatic transmission 14 of FIG. 1, and the operation amount (accelerator opening) Acc of the accelerator pedal 50 is an accelerator operation. It is detected by the quantity sensor 51. The accelerator pedal 50 is largely depressed according to the driver's requested output amount, and corresponds to an accelerator operation member, and the accelerator operation amount Acc corresponds to the requested output amount. In addition, an electronic throttle valve 56 whose opening degree θ _TH is changed by a throttle actuator 54 is provided in the intake pipe of the engine 10. In addition, an intake air amount sensor 60 for detecting an intake air quantity Q of the engine rotational speed sensor 58, the engine 10 for detecting the rotational speed NE of the engine 10, the intake for detecting the temperature T _A of intake air The air temperature sensor 62, the throttle valve 64 with an idle switch for detecting the fully closed state (idle state) of the electronic throttle valve 56 and the opening degree θ _TH, and the rotational speed (output shaft) of the output gear 34 corresponding to the vehicle speed V a vehicle speed sensor 66 for detecting the corresponding) N _OUT of the rotational speed, the cooling water temperature sensor 68 for detecting the cooling water temperature T _W of the engine 10, a brake switch 70 for detecting the presence or absence of foot brake operation, the shift lever 72 Lever position sensor 74 for detecting the lever position (operation position) _PSH of the turbine, and detecting the turbine rotation speed NT Are provided with a turbine rotation speed sensor 76, an AT oil temperature sensor 78 for detecting an AT oil temperature T _OIL that is the temperature of the hydraulic oil in the hydraulic control circuit 98, an ignition switch 82, and the like. , Engine speed NE, intake air amount Q, intake air temperature T _A , throttle valve opening θ _TH , vehicle speed V (output shaft rotation speed N _OUT ), engine coolant temperature T _W , presence / absence of brake operation, shift lever 72 A signal representing the lever position P _SH , turbine rotational speed NT, AT oil temperature T _OIL , operation position of the ignition switch 82, etc. is supplied to the electronic control unit 90. The turbine rotational speed NT is the same as the rotational speed of the input shaft 32 (input shaft rotational speed N _IN ) that is an input member.

The hydraulic control circuit 98 includes a circuit shown in FIG. 5 regarding the shift control of the automatic transmission 14. In FIG. 5, the hydraulic oil pumped from the oil pump 40 is adjusted to a first line pressure PL <b> 1 by being regulated by a relief type first pressure regulating valve 100. The oil pump 40 is, for example, a mechanical pump that is rotationally driven by the engine 10. The first pressure regulating valve 100 regulates the first line pressure PL1 according to the turbine torque T _T, that is, the input torque T _IN of the automatic transmission 14, or the throttle valve opening θ _TH that is a substitute value thereof. The one-line pressure PL1 is supplied to the manual valve 104 that is interlocked with the shift lever 72. Then, when the shift lever 72 is operated to the forward drive position such as "D" position is a forward position pressure P _D of the same size from the manual valve 104 and the first line pressure PL1 is the linear solenoid valve SL1~SL5 Supplied. The linear solenoid valves SL1 to SL5 are arranged corresponding to the clutches C1 and C2 and the brakes B1 to B3, respectively, and the excitation state is controlled according to the drive signal output from the electronic control unit 90, respectively. The engagement hydraulic pressures P _C1 , P _C2 , P _B1 , P _B2 , and P _B3 are independently controlled, so that any one of the first speed gear stage “1st” to the sixth speed gear stage “6th” is controlled. Alternatively, it can be established. The linear solenoid valves SL1 to SL5 are all of a large capacity type, and the output hydraulic pressure is supplied to the clutches C1 and C2 and the brakes B1 to B3 as they are, and their engagement hydraulic pressures P _C1 , P _C2 , P _B1 , P _B2 , P Direct pressure control that directly controls _B3 is performed.

  The electronic control unit 90 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and follows a program stored in the ROM in advance. By performing signal processing, the respective functions of the engine control means 120 and the shift control means 130 are executed as shown in FIG. 6, and are configured separately for engine control and shift control as required. Is done.

The engine control means 120 controls the output of the engine 10 and controls the opening and closing of the electronic throttle valve 56 by the throttle actuator 54, as well as controlling the fuel injection valve 92 for controlling the fuel injection amount. Therefore, the ignition device 94 such as an igniter is controlled. Control of the electronic throttle valve 56, for example, drives the throttle actuator 54 based on the actual accelerator operation amount Acc from the relationship shown in FIG. 7, the accelerator operation amount Acc increases the throttle valve opening θ _TH as increases. Further, when the engine 10 is started, cranking is performed by a starter (electric motor) 96.

The shift control means 130 performs shift control of the automatic transmission 14, and is automatically performed based on the actual throttle valve opening _θTH and the vehicle speed V from a previously stored shift diagram (shift map) shown in FIG. The gear stage to which the transmission 14 is to be shifted is determined, that is, the shift determination from the current gear stage to the shift destination gear stage is executed, and the shift output for starting the shift operation to the determined gear stage is executed. In addition, the excitation states of the linear solenoid valves SL1 to SL5 of the hydraulic control circuit 98 are set so that a shift shock such as a change in driving force does not occur and the durability of the friction material of the clutch C and the brake B is not impaired. Change continuously. As is apparent from FIG. 2, the automatic transmission 14 according to this embodiment is configured so that a continuous gear is released by a clutch-to-clutch shift in which one of the clutch C and the brake B is released and the other is engaged. Shifting of gears is performed. The solid line in FIG. 8 is an upshift line, and the broken line is a downshift line so that as the vehicle speed V decreases or the throttle valve opening _θTH increases, the gear position on the low speed side with a large gear ratio can be switched. In the figure, “1” to “6” mean the first speed gear stage “1st” to the sixth speed gear stage “6th”.

  When the shift lever 72 is operated to the “D” position, the uppermost D range (automatic shift mode) that automatically shifts using all the forward gears “1st” to “6th” is established. It is done. Further, when the shift lever 72 is operated to the “4” to “L” position, the respective shift ranges of 4, 3, 2, and L are established. In the 4th range, the shift control is performed at the forward gear stage below the 4th speed gear stage “4th”, the shift control is performed at the forward gear stage below the 3rd speed gear stage “3rd” in the 3rd range, and the shift control is carried out at the 2nd range. The speed change control is performed at the forward gear stage below the second gear stage “2nd”, and is fixed at the first gear stage “1st” in the L range. Therefore, for example, if the shift lever 72 is operated from the “D” position to the “4” position, the “3” position, or the “2” position while traveling at the sixth speed gear stage “6th” of the D range, the shift range becomes D. 4 → 3 → 2 forcibly switched from sixth gear stage “6th” to fourth gear stage “4th”, third gear stage “3rd”, second gear stage “2nd” It is downshifted and the gear stage can be changed manually.

Here, in this embodiment, the hydraulic pressure P _C1 , P _C2 , P _B1 , P _B2 , or P _B3 of the hydraulic oil supplied to a predetermined engagement side frictional engagement device (clutch C or brake B) is raised to increase. When executing the shift, the hydraulic pressure command value, that is, the exciting current for the linear solenoid valves SL1 to SL5 is changed according to a different change pattern depending on whether the power ON upshift in the driving state or the power OFF upshift in the driven state. ing. In the case of the automatic transmission 14 of the present embodiment, the engagement side frictional engagement device engaged by the upshift is the first brake B1, 2 in the 1 → 2 upshift, and the third brake B3, 3 in the 3 → upshift. The second clutch C2, in the 4 upshift, the third brake B3 in the 4 → 5 upshift, and the first brake B1 in the 5 → 6 upshift.

  The power ON (driving state) is a state in which the accelerator pedal 50 is depressed and power is transmitted from the engine 10 side to the wheel side. In the power OFF (driven state), the accelerator pedal 50 is not depressed. This is an engine brake state in which power is transmitted from the wheel side to the engine 10 side when the accelerator is off. Whether the power is ON or OFF can be determined simply by whether the idle switch is OFF or ON. For example, it can be determined by the magnitude of the engine speed NE and the turbine speed NT. If NE ≧ NT, the power is ON. If NE <NT, the power is OFF.

Further, at the time of power-on upshift, it is necessary to forcibly decrease the turbine rotational speed NT that is going to increase with the operation of the engine 10 by the engagement of the engagement side frictional engagement device. Since it is only necessary to engage the engagement side frictional engagement device after waiting for the turbine rotational speed NT to naturally decrease due to friction of the engine 10 or the like, the change pattern of the hydraulic pressure command value due to such a difference in the speed change mechanism Is different. The dotted line shown in the hydraulic pressure command value column in FIGS. 10 and 11 is an example of a change pattern of the hydraulic pressure command value (power ON side hydraulic pressure command value) at the time of power-on upshift, and the broken line indicates the hydraulic pressure command at the time of power-off upshift. It is an example of a value change pattern (power OFF side hydraulic pressure command value). In either case, in order to quickly fill the hydraulic cylinder with hydraulic oil (first fill), the hydraulic pressure command value is temporarily increased immediately after the shift command at time t ₁ and then gradually increased at a predetermined timing. Thus, the engagement side frictional engagement device is smoothly engaged so as to suppress the shift shock, but it is necessary to forcibly decrease the turbine rotational speed NT in the power ON upshift as described above. Therefore, the overall hydraulic pressure command value is higher than the power OFF hydraulic pressure command value. The power ON-side oil pressure command value is increased gradually from the time the inertia phase is detected t _2, the power OFF hydraulic pressure command value to the time t ₄ when the turbine rotation speed NT reaches near the synchronous rotational speed after shifting Is held at a low-pressure command value at which the engagement-side friction engagement device is maintained in the non-engagement state, and is gradually increased from time t ₄ .

  On the other hand, when the accelerator pedal 50 is returned to the driven state during the power ON upshift, that is, before the engagement side frictional engagement device is completely engaged, it is caused by a sudden engagement or the like. In order to prevent a shock, a hydraulic command value switching means 132 (see FIG. 6) functionally provided in the electronic control unit 90 can switch from a power ON side hydraulic command value to a power OFF side hydraulic command value. ing. FIG. 9 is a flowchart for explaining the specific contents of the signal processing executed by the hydraulic command value switching means 132. The white arrow shown in the hydraulic command value column of FIG. 10 indicates the hydraulic command value according to the flowchart of FIG. Is switched.

  FIG. 9 is executed during the upshift. In step S1, it is determined whether or not the power ON upshift is being controlled based on, for example, the hydraulic control based on the power ON side hydraulic command value. If the power ON upshift is under shift control, step S2 and the subsequent steps are executed. However, if it is not a power ON upshift, that is, a power OFF upshift, this switching control is terminated, and the power OFF side hydraulic pressure is In accordance with the command value, hydraulic control of the engagement side frictional engagement device, specifically, excitation current control of the linear solenoid valves SL1 to SL5 corresponding to the engagement side frictional engagement device is performed. In step S1, it is not determined whether or not the power is actually turned on, that is, whether it is in the driven state or the driven state, and YES even during the hydraulic control based on the power ON side hydraulic pressure command value even if the driving state is changed. Judgment is made.

In step S2, it is determined whether or not the driving state is changed to the driven state based on, for example, whether or not the idle switch is turned on or whether or not the turbine rotational speed NT is higher than the engine rotational speed NE. . When the driving state changes to the driven state, step S3 and subsequent steps are executed. If the driving state remains, the switching control is terminated, and the engagement side frictional engagement device is operated according to the power ON side hydraulic pressure command value. Is controlled through the control of the excitation current of the corresponding linear solenoid valves SL1 to SL5. Time t _{3 in} FIG. 10 is a time when the depression operation of the accelerator pedal 50 is released to change from the driving state to the non-driving state, and the determination of step S2 becomes YES (affirmation), and a shift command (time t ₁ ) From time to time t ₃ , the hydraulic pressure control is performed according to the power ON side hydraulic pressure command value indicated by the one-dot chain line. In this embodiment, the driving state changes to the non-driving state after time t ₂ when the inertia phase starts.

In step S3 executed when the driving state changes to the driven state, the power ON side hydraulic pressure command value is switched to the power OFF side hydraulic pressure command value. In order to be able to switch from the power ON side hydraulic pressure command value to the power OFF side hydraulic pressure command value at any time, the power ON side hydraulic pressure command value and the power OFF side hydraulic pressure command value are respectively changed to the shift command at time t ₁ . Accordingly, the oil pressure command value in FIG. 10 is changed in a predetermined change pattern in parallel as indicated by the one-dot chain line and the broken line, and the oil pressure control value is controlled using the power ON side oil pressure command value during the power ON upshift. When the power is turned off, the hydraulic pressure control is performed using the power-off side hydraulic pressure command value.

  Steps S4 to S6 are related to the hydraulic control at the time of transition to switch from the power ON side hydraulic command value to the power OFF side hydraulic command value. In Step S4, the current power ON side hydraulic command value and the power OFF side hydraulic command to be switched are selected. The value is compared, and it is determined whether or not the power ON side hydraulic pressure command value is larger. When the power ON side hydraulic pressure command value> the power OFF side hydraulic pressure command value, steps S5 and S6 are executed and step S4 is repeated, but if the power OFF side hydraulic pressure command value ≧ the power ON side hydraulic pressure command value, The switching control is terminated, and the hydraulic control of the engagement side frictional engagement device is performed via the excitation current control of the corresponding linear solenoid valves SL1 to SL5 according to the power OFF side hydraulic pressure command value.

In step S5, the power ON side hydraulic pressure command value is decreased by a certain amount every cycle so as to change from the power ON side hydraulic pressure command value to the power OFF side hydraulic pressure command value with a predetermined gradient. In S6, the excitation current of the corresponding linear solenoid valves SL1 to SL5 is controlled according to the power ON side hydraulic pressure command value determined in step S5, and the hydraulic pressures P _C1 , P _C2 , P _B1 , P of the engagement side frictional engagement device are controlled. _B2 or _PB3 is controlled. By repeating steps S5 and S6 until the determination in step S4 becomes NO (negative), the power ON side hydraulic pressure command value decreases with a predetermined gradient as shown by the white arrow in the hydraulic pressure command value column of FIG. The hydraulic pressure P _C1 , P _C2 , P _B1 , P _B2 , or P _B3 of the engagement side frictional engagement device is smoothly lowered according to the decrease in the power ON side hydraulic pressure command value. Thereby, the output torque is also changed smoothly, and a shock due to a sudden torque loss is prevented. A graph indicated by a broken line in the column of output torque in FIG. 10 shows a case where the power ON side hydraulic command value is directly switched from the power ON side hydraulic command value in accordance with the change from the driving state to the driven state as shown in FIG. A shock due to sudden torque loss occurs.

Here, in this embodiment, large-capacity linear solenoid valves SL1 to SL5 are used, and the output hydraulic pressure is supplied as it is to the engagement side frictional engagement device, and the engagement hydraulic pressures P _C1 , P _C2 , Since direct pressure control is performed in which P _B1 , P _B2 and P _B3 are directly controlled, the hydraulic pressures P _C1 , P _C2 , P _B1 , P _B2 and P _{B3 of the} actual friction engagement device are high in response according to the hydraulic pressure command value. Control (followability). Therefore, when the power ON side hydraulic pressure command value is gradually lowered at a predetermined gradient by executing steps S5 and S6, the actual hydraulic pressure P _C1 , P _C2 , P _B1 , P _B2 , or P _B3 is also the hydraulic pressure command value. Therefore, by appropriately determining the gradient of the hydraulic pressure command value, it is possible to cause a torque change intended by the driver while preventing a shock due to sudden torque loss. The predetermined gradient of the hydraulic pressure command value is a predetermined value in advance so that the torque change intended by the driver can be obtained for each type of friction engagement device or for each shift type of upshift from which gear stage to which gear stage. Is determined and is changed with a constant gradient until the power OFF hydraulic pressure command value is reached.

As described above, according to the hydraulic control device of the present embodiment, the hydraulic pressure command value is set to the predetermined value when the power ON side hydraulic pressure command value is switched from the power ON side hydraulic pressure command value in accordance with the change from the driving state to the driven state. Therefore, the hydraulic pressure P _C1 , P _C2 , P _B1 , P _B2 , or P _B3 of the hydraulic oil supplied to the engagement side frictional engagement device is prevented from suddenly decreasing, and torque is reduced. Shock due to omission is suppressed.

In particular, in this embodiment, large-capacity linear solenoid valves SL1 to SL5 are used, and the output hydraulic pressure is supplied to the engagement side frictional engagement device as it is, and the engagement hydraulic pressures P _C1 , P _C2 , Since P _B1 , P _B2 and P _B3 are directly controlled, the hydraulic pressures P _C1 , P _C2 , P _B1 , P _B2 and P _{B3 of the} actual friction engagement device are controlled with high responsiveness according to the hydraulic pressure command value. By appropriately determining the gradient of the command value, a torque change intended by the driver can be obtained while preventing a shock due to sudden torque loss.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention is implemented in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.

1 is a schematic diagram of a vehicle drive device to which the present invention is applied. FIG. 2 is a diagram illustrating engagement and disengagement states of clutches and brakes for establishing each gear stage of the automatic transmission of FIG. 1. It is a figure explaining the input-output signal of the electronic control apparatus provided in the vehicle of the Example of FIG. It is a figure which shows an example of the shift pattern of the shift lever of FIG. FIG. 4 is a circuit diagram illustrating a configuration of a portion related to shift control of the automatic transmission in the hydraulic control circuit of FIG. 3. It is a block diagram explaining the function with which the electronic control apparatus of FIG. 3 is provided. Is a diagram showing an example of a relationship between the accelerator operation amount Acc and the throttle valve opening theta _TH used in the throttle control performed by the engine control unit of FIG. It is a figure which shows an example of the shift map (map) used by the shift control of the automatic transmission performed by the shift control means of FIG. FIG. 7 is a flowchart for specifically explaining the processing content of a hydraulic pressure command value switching unit in FIG. 6. FIG. FIG. 10 is an example of a time chart when a hydraulic pressure command value switching process is performed according to the flowchart of FIG. 9 when the state is changed to a driven state during a power ON upshift. FIG. FIG. 10 is an example of a time chart when the power ON side hydraulic pressure command value is directly switched to the power OFF side hydraulic pressure command value.

Explanation of symbols

  14: Automatic transmission 90: Electronic control unit 130: Transmission control unit 132: Hydraulic pressure command value switching unit C1, C2: Clutch (friction engagement device) B1 to B3: Brake (friction engagement device)

Claims (1)

The present invention relates to an automatic transmission that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of hydraulic friction engagement devices, and increasing the hydraulic oil pressure supplied to a predetermined friction engagement device. In performing the upshift, if the accelerator is returned to the driven state during the power ON upshift in the driving state and changes to the driven state, the hydraulic pressure command value supplied to the friction engagement device is In a hydraulic control device for an automatic transmission having hydraulic command value switching means for switching from a power ON hydraulic command value to a power OFF hydraulic command value in a driven state,
The power ON side hydraulic pressure command value and the power OFF side hydraulic pressure command value are changed in a predetermined change pattern in parallel with the power ON upshift command, and are appropriately selected according to the power ON and OFF. Has been used for hydraulic control,
The hydraulic pressure command value switching means, when switching from the power ON hydraulic pressure command value to the power OFF hydraulic pressure command value, the power ON hydraulic pressure command value is gradually decreased at a predetermined gradient, the power OFF hydraulic pressure command When the value reaches the value, the control is switched to the hydraulic control using the power OFF side hydraulic pressure command value .

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