JP2013029154A - Hydraulic control device of vehicle automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device of a vehicle automatic transmission that prevents transmission shock at power-on downshift.SOLUTION: In the power-on downshift which is output during a depressing operation of an accelerator pedal 44, when a return operation of the accelerator pedal 44 is performed during the power-on downshift, a higher oil pressure than an oil pressure corresponding to an accelerator operation amount after the return operation when the return operation is not performed is supplied to a release-side engagement element. As a result, even when a change in engine torque is delayed in response to an accelerator operation, the oil pressure supplied to the release-side engagement element is set higher than that when the return operation of the accelerator is not performed, and thereby engagement controllability of the release-side engagement element is improved to prevent the generation of the transmission shock properly.

Description

  The present invention relates to a hydraulic control device for a vehicle automatic transmission, and more particularly to an improvement for suppressing a shift shock during a power-on downshift.

  Various types of stepped automatic transmissions that include a plurality of hydraulic engagement elements and selectively establish one of a plurality of shift stages according to a combination of engagement and release of each of the plurality of engagement elements Widely used in In addition, there has been proposed a hydraulic control device that suppresses a shift shock at the time of power-on downshift in such a vehicle automatic transmission. For example, this is the shift control method for an automatic transmission described in Patent Document 1. According to this technology, even when the input rotational speed increases at the time of power-on downshift, the application hydraulic pressure is applied at an appropriate timing to prevent shift shock and engine rotation. ing.

JP 2005-337410 A JP 2010-007767 A

  However, in the conventional technology, when the accelerator pedal is returned during the downshift of the automatic transmission, that is, the power-on downshift, which is output during the depression of the accelerator pedal, the accelerator operation is supported. As a result, there may be a delay in the change of the engine torque. For this reason, in the hydraulic control device that controls the hydraulic pressure supplied to the automatic transmission based on the accelerator operation amount, there is a possibility that a shift shock may occur in the power-on downshift. In particular, when the gear stage after the shift is a gear stage established by releasing the disengagement engagement element and engaging the one-way clutch, the shift control is performed exclusively by controlling the hydraulic pressure supplied to the disengagement engagement element. Therefore, there is a high possibility that a shift shock due to a delay in changing the engine torque will occur. Such a problem has been newly found in the process of continuous research by the present inventors with the intention of reducing the shift shock of the automatic transmission for vehicles.

  The present invention has been made against the background of the above circumstances, and an object thereof is to provide a hydraulic control device for an automatic transmission for a vehicle that suppresses a shift shock during a power-on downshift. .

  In order to achieve such an object, the gist of the first aspect of the present invention includes a one-way clutch and a plurality of hydraulic engagement elements, and the engagement and release of each of the one-way clutch and the plurality of engagement elements. In a stepped automatic transmission that selectively establishes one of a plurality of shift speeds in accordance with the combination of the vehicle, for a vehicle that controls the hydraulic pressure supplied to the hydraulic engagement element based on an accelerator pedal operation amount A hydraulic control device for an automatic transmission, which is configured to release a disengagement-side engagement element having a gear ratio larger than that of the first gear stage from the first gear stage of the automatic transmission by operating an accelerator pedal. In a power-on downshift to the second gear stage established by engagement of the one-way clutch, when the accelerator pedal is returned during the power-on downshift And it is characterized in that supplying higher than the hydraulic pressure corresponding to the accelerator return operation amount after operation in case the return operation is not performed in the release-side engaging element.

  Thus, according to the first aspect of the present invention, the disengagement-side engagement element having a gear ratio larger than that of the first gear stage is released from the first gear stage of the automatic transmission by the operation of the accelerator pedal. In the power-on downshift to the second gear stage established by the engagement of the one-way clutch, when the accelerator pedal is returned during the power-on downshift, the return operation is Since the hydraulic pressure higher than the hydraulic pressure corresponding to the accelerator operation amount after the return operation when not performed is supplied to the disengagement side engagement element, the change in the engine torque is delayed in response to the accelerator operation. Even if there is, the supply hydraulic pressure to the disengagement side engagement element is set higher than when the accelerator return operation is not performed. It is possible to suitably suppress the occurrence of shift shock by improving the Gosei. That is, it is possible to provide a hydraulic control device for a vehicle automatic transmission that suppresses a shift shock during a power-on downshift.

  Here, the gist of the second invention subordinate to the first invention is that, when the accelerator pedal is returned during the power-on downshift, the return operation is not performed. The hydraulic pressure supplied to the disengagement-side engagement element is kept at a constant pressure at a hydraulic pressure higher than the hydraulic pressure corresponding to the accelerator operation amount after the return operation. In this way, even when there is a delay in the change in engine torque corresponding to the accelerator operation, the supply hydraulic pressure to the disengagement engagement element is constant at a higher pressure than when the accelerator return operation is not performed. Since it is made to wait, the engagement controllability of the disengagement side engagement element can be improved and the occurrence of a shift shock can be suitably suppressed.

  Further, the gist of the third invention subordinate to the first invention or the second invention is that when the accelerator pedal is returned during the power-on downshift, the return operation is performed. In this case, the hydraulic pressure supplied to the disengagement-side engagement element is gradually decreased with a gentler gradient than the gradually decreasing gradient of the hydraulic pressure corresponding to the accelerator operation amount after the return operation in the case where the return operation is not performed. In this way, even when there is a delay in the change in engine torque in response to the accelerator operation, the hydraulic pressure supplied to the disengagement side engagement element gradually decreases with a gentler slope than when the accelerator return operation is not performed. Since (sweep control) is performed, it is possible to improve the engagement controllability of the disengagement side engagement element and to suitably suppress the occurrence of a shift shock.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a skeleton diagram illustrating a configuration of a vehicle automatic transmission to which the present invention is preferably applied. FIG. 2 is an operation table for explaining an operation state of engagement elements when a plurality of shift stages are selectively established in the automatic transmission of FIG. 1. It is a figure explaining the control system of the automatic transmission of FIG. It is a figure which shows an example of the shift map used for the shift determination in the automatic transmission of FIG. It is a figure which illustrates the structure used for the shift control of the automatic transmission among the hydraulic control circuits with which the automatic transmission of FIG. 1 was equipped. It is a functional block diagram explaining the principal part of the control function with which the electronic control apparatus in the automatic transmission of FIG. 1 was equipped. It is a figure which shows an example of the relationship used for estimation of the engine torque by the electronic controller in the automatic transmission of FIG. 2 is a time chart showing temporal changes of respective relational values during a power-on downshift from a second gear to a first gear in the automatic transmission of FIG. 1. 2 is a flowchart for explaining a main part of 2 → 1 power-on downshift control by an electronic control unit in the automatic transmission of FIG. 1.

  The present invention is preferably applied to a case where a downshift is performed in a vehicle deceleration state when the accelerator pedal is being depressed when the vehicle is traveling on an uphill road. Preferably, in such a case, when the amount of return of the accelerator pedal after the shift output is equal to or greater than a predetermined value, the operation of returning the hydraulic pressure supplied to the disengagement side engagement element is not performed. Perform correction to set higher than the case. For example, the engine torque is estimated based on the intake air amount or the like from a predetermined relationship, and it is determined whether or not the accelerator pedal is returned based on the estimation result. Preferably, it is determined that the accelerator pedal has been returned when the estimated engine torque is equal to or greater than a predetermined value and the accelerator opening is equal to or less than a predetermined value.

  Further, the constant pressure standby time of the disengagement side engagement element is preferably a predetermined constant value, and is equal to the constant pressure standby time in the case where the accelerator pedal is not returned, that is, in the conventional control. However, control such as a longer time than when the return operation is not performed may be performed. Further, a control may be performed in which the constant pressure waiting time of the disengagement side engagement element is changed based on a vehicle traveling state such as an accelerator opening degree or a vehicle speed from a predetermined relationship.

  The release-side engagement element is subjected to sweep control that is gradually decreased to a release value (for example, 0) after the constant pressure standby, and preferably the hydraulic pressure is changed in a linear function. . That is, the gradient preferably corresponds to a gradient in a linear function change of hydraulic pressure, but is not necessarily limited to a linear function change, and the accelerator return operation is not performed. If it can be gradually decreased more gradually (at a low rate of change), the present invention has a temporary effect.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a skeleton diagram illustrating a configuration of an automatic transmission 10 for a vehicle to which the present invention is preferably applied. FIG. 2 is a diagram when a plurality of shift stages are selectively established in the automatic transmission 10. It is an action | operation table | surface explaining the action | operation state of an engagement element. The automatic transmission 10 is a laterally mounted device that is preferably used for an FF (front engine / front drive) type vehicle or the like. The automatic transmission 10 includes a single pinion type first planetary gear device 12 as a main component. A transmission unit 14 and a second transmission unit 20 configured as a Ravigneaux type mainly composed of a double pinion type second planetary gear unit 16 and a single pinion type third planetary gear unit 18 are provided on a coaxial line, and are input. The rotation of the shaft 22 is changed and output from the output rotating member 24. The input shaft 22 corresponds to an input member. In this embodiment, the input shaft 22 is a turbine shaft of a torque converter 30 that is rotationally driven by an engine 28 that is an internal combustion engine for generating vehicle power. The output rotating member 24 corresponds to the output member of the automatic transmission 10, and an output gear or differential gear that meshes with a differential driven gear (large diameter gear) to transmit power to a differential gear device (not shown). It functions as a drive gear. The output of the engine 28 is transmitted to a pair of drive wheels (front wheels) via the torque converter 30, the automatic transmission 10, the differential gear device, and a pair of axles as drive shafts. . The automatic transmission 10 is substantially symmetrical with respect to the center line, and the lower half of the center line is omitted in FIG. This is the same in the following description.

  The engine 28 is a driving source (main power source) that generates driving force for traveling, and is an internal combustion engine such as a gasoline engine or a diesel engine that generates driving force of a vehicle by combustion of fuel. The torque converter 30 includes a pump impeller 30a connected to the crankshaft of the engine 28, a turbine impeller 30b connected to the input shaft 22 of the automatic transmission 10, and the one-way clutch. And a stator impeller 30c coupled to a housing (transmission case) 26 of the automatic transmission 10, and fluid transmission for transmitting the power generated by the engine 28 to the automatic transmission 10 via fluid. Device. Further, a lockup clutch 32, which is a direct coupling clutch, is provided between the pump impeller 30a and the turbine impeller 30b so as to be engaged, slipped, or released by hydraulic control or the like. It has become. When the lockup clutch 32 is completely engaged, the pump impeller 30a and the turbine impeller 30b are integrally rotated.

  The operation table of FIG. 2 summarizes the relationship between the shift speeds established by the automatic transmission 10 and the operation states of the clutches C1, C2 and the brakes B1, B2, B3. , “◎” represents engagement only during engine braking, and the blank represents release. The clutches C1 and C2 and the brakes B1, B2 and B3 (hereinafter simply referred to as the clutch C and the brake B unless otherwise specified) provided in the automatic transmission 10 are engaged by a hydraulic actuator such as a multi-plate clutch or a brake. This is a hydraulic friction engagement device that is jointly controlled, and the engagement and release states are switched and engaged by excitation, de-excitation and current control of the linear solenoid valve provided in the hydraulic control circuit 52 shown in FIG. The transient oil pressure at the time of release is controlled. A one-way clutch F1 is provided in parallel with the brake B2 between the housing 26 and the ring gear R2 (R3). The one-way clutch F1 is engaged when the automatic transmission 10 (input shaft 22) is driven to prevent relative rotation between the housing 26 and the ring gear R2 (R3), but is not driven (when the engine is braked). ) Is idled to allow relative rotation between the housing 26 and the ring gear R2 (R3).

  In the automatic transmission 10, the first speed change according to the combination of the connected states of the rotating elements (sun gears S <b> 1 to S <b> 3, carriers CA <b> 1 to CA <b> 3, ring gears R <b> 1 to R <b> 3) of the first transmission unit 14 and the second transmission unit 20. Six forward shift stages from the stage “1st” to the sixth shift stage “6th” are established, and the reverse shift stage of the reverse shift stage “R” is established. As shown in FIG. 2, for example, in the forward gear stage, the first speed gear stage “1st” is established by the engagement of the clutch C1 and the brake B2. Further, the second speed gear stage “2nd” is established by the engagement of the clutch C1 and the brake B1. Further, the third speed gear stage “3rd” is established by the engagement of the clutch C1 and the brake B3. Further, the fourth gear stage “4th” is established by engagement of the clutch C1 and the clutch C2. Further, the fifth speed gear stage "5th" is established by engagement of the clutch C2 and the brake B3. Further, the sixth speed gear stage “6th” is established by engagement of the clutch C2 and the brake B1. Further, the reverse gear "Rev" is established by the engagement of the brake B2 and the brake B3. Further, both the clutch C and the brake B are configured to be in a neutral state by being released. Further, in the automatic transmission 10 of the present embodiment, the brake B2 that establishes the first shift stage “1st” is provided with the one-way clutch F1 in parallel. Therefore, during acceleration (during driving) such as starting. Does not necessarily have to engage the brake B2. Therefore, the brake B2 that establishes the first shift stage “1st” is operated (engaged) during engine braking, and is engaged because the one-way clutch F1 is engaged during driving, that is, during power-on shift. I can't. Further, the gear ratios of the respective gear stages are the gear ratios of the first planetary gear device 12, the second planetary gear device 16, and the third planetary gear device 18 (= number of teeth of the sun gear / number of teeth of the ring gear) ρ1, ρ2. , Ρ3 as appropriate.

  FIG. 3 is a diagram illustrating a control system of the automatic transmission 10. As shown in FIG. 3, the automatic transmission 10 is provided with an electronic control unit 50 for performing various controls including hydraulic control related to the shift control. The electronic control unit 50 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, for example, and the CPU stores a program stored in the ROM in advance using a temporary storage function of the RAM. In accordance with the signal processing, the shift control of the automatic transmission 10 is executed. Further, the automatic transmission 10 is provided with a storage device 48 for storing relationships used for various controls by the electronic control device 50, and the electronic control device 50 is stored in the storage device 48. Based on the relationship, the above-described various controls are executed based on the running state of the vehicle. In addition, a hydraulic control circuit 52 that adjusts a predetermined hydraulic pressure according to a command from the electronic control unit 50 is provided in order to perform shift control of the automatic transmission 10 and the like. That is, the electronic control device 50 corresponds to a hydraulic control device for a vehicle automatic transmission that controls the hydraulic pressure supplied to the automatic transmission 10 via the hydraulic control circuit 52.

Further, as shown in FIG. 3, the electronic control device 50 is input with signals from various sensors provided in each part of the vehicle and indicating the state of the vehicle. That is, the accelerator opening signal indicating the accelerator opening degree A _CC corresponding to the operation amount (depression amount) of the accelerator pedal 44 detected by the accelerator opening sensor 34, and the rotation of the engine 28 detected by the engine speed sensor 36. engine rotational speed signal representing the speed N _E, the detected turbine rotational speed N _T i.e. the turbine speed signal representative of the output rotational speed of the torque converter 30 by a turbine rotational speed sensor 38, the automatic transmission detected by the vehicle speed sensor 40 A vehicle speed signal representing the vehicle speed V corresponding to the output rotational speed of the machine 10, an intake air amount signal representing the intake air amount Q _A of the engine 28 detected by the intake air amount sensor 42, and the like are supplied. Yes. In addition, the electronic control device 50 outputs a control signal for controlling the operation of equipment provided in each part of the vehicle. Further, as will be described in detail below, a control command for controlling the output hydraulic pressure is output to various electromagnetic control valve devices provided in the hydraulic control circuit 52.

FIG. 5 controls the operation of hydraulic actuators (hydraulic cylinders) AC1, AC2, AB1, AB2, AB3 provided corresponding to the clutches C1, C2 and brakes B1-B3 in the hydraulic control circuit 52, respectively. It is a circuit diagram regarding the linear solenoid valves SL1 to SL5. In FIG. 5, each hydraulic actuator AC1, AC2, AB1, AB2, AB3 has a line hydraulic pressure PL applied to linear solenoid valves SL1-SL5, respectively, and engagement pressures PC1, PC2 according to a command signal from the electronic control unit 50. , PB1, PB2, and PB3 are regulated and supplied directly. The line oil pressure PL is obtained by using, for example, a relief type pressure regulating valve (regulator valve) as an accelerator opening A _CC or an oil pressure generated by an electric oil pump (not shown) or a mechanical oil pump that is rotationally driven by the engine 28. The pressure is adjusted to a value corresponding to the engine load or the like represented by the throttle opening. In addition, the linear solenoid valves SL1 to SL5 shown in FIG. 5 have basically the same configuration, and are individually excited / de-energized by the electronic control unit 50, whereby the hydraulic actuators AC1, AC2, AB1, The engagement pressures PC1, PC2, PB1, PB2, and PB3 of the clutches C1 and C2 and the brakes B1 to B3 are controlled by controlling the hydraulic pressures of the AB2 and AB3 independently. In the automatic transmission 10, for example, as shown in the engagement operation table of FIG. 2, each gear stage is established by engaging a predetermined engagement device. In the shift control of the automatic transmission 10, for example, a so-called clutch-to-clutch shift is performed in which the release and engagement of the clutch C and the brake B involved in the shift are controlled simultaneously.

FIG. 6 is a functional block diagram for explaining the main part of the control function provided in the electronic control unit 50. The shift determination means 60 shown in FIG. 6 determines a shift stage to be established in the automatic transmission 10 based on a traveling state of the vehicle based on a predetermined relationship. For example, it is detected by the accelerator opening degree A _CC detected by the accelerator opening degree sensor 36 and the vehicle speed sensor 40 from the relationship (shift diagram) as shown in FIG. On the basis of the vehicle speed V, the shift stage to be established in the automatic transmission 10 is determined. In FIG. 4, the upshift shift line, that is, the shift line used for determining the shift from the low speed stage side to the high speed stage side is a solid line, and the downshift shift line, that is, the determination of the shift from the high speed stage side to the low speed stage side. The shift lines used in are shown by broken lines.

  The shift control means 62 performs shift control of the automatic transmission 10 based on the determination result of the shift determination means 60. Specifically, the hydraulic control circuit 52 is configured so that the shift determined by the shift determination unit 60 is performed in the automatic transmission 10 (so that the shift stage determined by the shift determination unit 60 is established). The hydraulic pressure for controlling the engagement state of the clutch C and the brake B is controlled via the linear solenoid valves SL1 to SL5 and the like provided in the engine. Further, as shown in FIG. 6, the shift control means 62 includes a release side hydraulic pressure correction means 64. The release-side hydraulic pressure correction means 64 is based on the determination result by the accelerator operation amount determination means 66 and is supplied to the release-side engagement element (engagement element released at the time of shift) in the automatic transmission 10. Correct. Hereinafter, the control of the release side hydraulic pressure correction means 64 and the accelerator operation amount determination means 66 will be described.

The accelerator operation amount determination means 66 determines whether or not a return operation of the accelerator pedal 44 has been performed during the power-on downshift achieved by the engagement of the one-way clutch F1 in the automatic transmission 10. The return operation of the accelerator pedal 44 is an operation in a direction in which the accelerator opening degree A _cc detected by the accelerator opening degree sensor 34 is decreased, that is, a stepping back operation of the accelerator pedal 44. It is determined that the return operation of the accelerator pedal 44 has been performed when the rate of decrease of A _CC (the amount of decrease per unit time) is equal to or greater than a predetermined threshold.

Further, the accelerator operation amount determination unit 66 is preferably estimates the output torque that is, the engine torque T _E of the engine 28, whether the return operation of the accelerator pedal 44 based on the estimation result is performed judge. For example, from the storage device as shown in FIG. 7 which is stored in 48 relation predetermined (estimation map), the engine rotational speed N _E and the intake air quantity sensor 42 detected by the engine rotational speed sensor 36 When the engine torque T _E is estimated based on the detected intake air amount Q _A, and the deviation of the accelerator opening degree A _CC from the estimated engine torque T _E is equal to or greater than a predetermined reference value Determines that the return operation of the accelerator pedal 44 has been performed. In the configuration having an engine torque sensor for detecting an output torque of the engine 28, performs such determination on the basis of a deviation of the accelerator opening A _CC for the engine torque sensor by the detected engine torque T _E It may be. Specifically, when the estimated engine torque _TE is not less than a predetermined value and the accelerator opening degree A _CC detected by the accelerator opening sensor 34 is not more than a predetermined value. It is determined that the return operation of the accelerator pedal 44 has been performed.

  The release-side hydraulic pressure correction means 64 is a power-on achieved by releasing the release-side engagement element and engaging the one-way clutch F1 in the automatic transmission 10, which is output during the depression operation of the accelerator pedal 44. In the downshift, the hydraulic pressure supplied to the disengagement engagement element released in the power-on downshift is corrected. The power-on downshift achieved by the engagement of the one-way clutch F1 is, for example, from the second gear stage “2nd” to the first gear stage “1st” of the automatic transmission 10 shown in FIG. Equivalent to downshift. In the downshift from the second speed gear stage “2nd” to the first speed gear stage “1st”, the brake B1 corresponds to the disengagement side engagement element. Alternatively, in the downshift from the third speed gear stage “3rd” to the first speed gear stage “1st”, the brake B3 corresponds to the disengagement side engagement element. That is, the release-side hydraulic pressure correction means 64 is, for example, the second-speed gear stage “2nd” to the first-speed gear stage “" output during the depression operation of the accelerator pedal 44 in the automatic transmission 10 of the present embodiment. In the downshift to “1st”, the hydraulic pressure supplied to the brake B1 which is the disengagement side engagement element is corrected. Further, in the downshift from the third speed gear stage “3rd” output during the depression operation of the accelerator pedal 44 to the first speed gear stage “1st”, the brake B3 that is the disengagement side engagement element is supplied. Correct the oil pressure.

FIG. 8 is a time chart showing the time change of each related value during the power-on downshift from the second speed gear stage “2nd” to the first speed gear stage “1st” in the automatic transmission 10. Values corresponding to the control by the technology are indicated by solid lines, and values corresponding to the control of the present embodiment are indicated by broken lines. In the control shown in FIG. 8, first, at time t1, a shift from the second speed gear stage “2nd” to the first speed gear stage “1st” in the automatic transmission 10 is output. Here, in the example shown in FIG. 8, the accelerator opening degree A _CC decreases at the time of the shift output at the time point t1. That is, the return operation of the accelerator pedal 44 is performed. Further, in response to the accelerator return operation, the turbine torque (input torque of the automatic transmission 10) corresponding to the output torque of the engine 28 is decreased. The decrease timing is the decrease timing of the accelerator opening degree _Acc . However, the decrease in the accelerator opening degree A _CC starts before the shift output, while the decrease in the turbine torque starts after the shift output. That is, it can be seen that there is a delay in the change of the engine torque with respect to the accelerator operation.

Further, as shown in FIG. 8, in the power-on down shift from the second speed gear stage “2nd” to the first speed gear stage “1st” in the automatic transmission 10 according to the prior art, the release is performed by the shift output at the time point t1. after the hydraulic pressure on the side engaging the brake B1 is coupling elements (brake release pressure) was reduced to a predetermined pressure standby pressure P _WA, allowed to stand during the constant pressure standby pressure P _WA waiting a predetermined time at tw Thereafter, sweep control is performed in which the hydraulic pressure of the brake B1 is gradually reduced to a release value (for example, 0). However, when the change in engine torque is delayed with respect to the accelerator operation as described above, the hydraulic pressure of the brake B1 cannot be set high considering the time of accelerator re-depression where a shift response is required. In downshifting during power-on and vehicle deceleration when traveling on an uphill road or the like, the speed of the turbine is increased rapidly because the torque ratio of the torque converter 30 is relatively high. At the time of synchronization, that is, before and after the engagement of the one-way clutch F1 at the time t2, there is a possibility that a fluctuation in acceleration in the front-rear direction, that is, a shift shock may occur as shown in the vehicle front-rear G in FIG.

On the other hand, in the power-on down shift from the second speed gear stage “2nd” to the first speed gear stage “1st” in the automatic transmission 10 according to the present embodiment, it is the disengagement side engagement element by the shift output at the time point t1. after hydraulic brake B1 has been reduced to a predetermined high pressure standby pressure P _WB than the hydraulic P _WA, brought into the waiting time tw standby predetermined by the pressure standby pressure P _WB. That is, the release side hydraulic pressure correction means 64 is preferably configured such that, as shown in FIG. 8, during the power-on downshift, the accelerator operation amount determination means 66 determines the return operation of the accelerator pedal 44. the, by a hydraulic or high pressure P _WB than pressure standby pressure P _WA in the prior art corresponding to the accelerator return operation amount after operation in case the return operation is not performed, a release side engagement element wherein The hydraulic pressure supplied to the brake B1 is kept at a constant pressure for a predetermined time tw. In other words, when the power-on downshift is output, the amount of decrease in the hydraulic pressure supplied to the brake B1 that is the disengagement side engagement element (the amount of decrease in the hydraulic pressure command value) is less than when the return operation is not performed. Also correct it to be smaller.

  Further, the release side hydraulic pressure correction means 64 is preferably, as shown in FIG. 8, when the accelerator operation amount determination means 66 determines the return operation of the accelerator pedal 44 during the power-on downshift. In the case where the return operation is not performed, the supply hydraulic pressure to the brake B1, which is the disengagement engagement element, is gradually decreased with a gentler gradient than the gradually decreasing gradient of the hydraulic pressure corresponding to the accelerator operation amount after the return operation. . In other words, in the sweep control in which the hydraulic pressure supplied to the brake B1 is gradually decreased from the constant pressure standby pressure to the release value, the amount of decrease in hydraulic pressure per unit time is less than when the return operation is not performed (control according to the prior art). Correct to make it smaller. In other words, the sweep amount is corrected so as to gradually decrease at a lower rate of time change than when the accelerator return operation is not performed. According to the control of the present embodiment as described above, the hydraulic pressure of the brake B1, which is the disengagement side engagement element, is set to be sufficiently high. Sufficient controllability can be ensured even in shifting, and the change in turbine rotation can be controlled by controlling the engagement hydraulic pressure of the brake B1 to suitably suppress the occurrence of a shift shock.

  FIG. 9 is a flowchart for explaining a main part of the 2 → 1 power-on downshift control by the electronic control unit 50, which is repeatedly executed at a predetermined cycle.

First, in step (hereinafter, step is omitted) S1, a power-on down shift from the second speed gear stage “2nd” to the first speed gear stage “1st” in the automatic transmission 10 is output. Next, in S2, the predetermined, as shown in FIG. 7 stored in the storage device 48 relation, the engine rotational speed N _E and the intake air quantity sensor 42 detected by the engine rotational speed sensor 36 An engine torque T _E is estimated based on the detected intake air amount Q _A , the estimated engine torque T _E is equal to or greater than a predetermined value, and an accelerator opening detected by the accelerator opening sensor 34 is detected. It is determined whether the degree A _CC is equal to or less than a predetermined value. If the determination in S2 is no, S3, the After pressure standby hydraulic pressure of the brake B1 by a hydraulic control or prior art similar pressure standby pressure P _WA when the accelerator return operation is not performed After the hydraulic pressure control gradually decreasing at a predetermined gradient is performed, the processing from S5 is executed. If the determination in S2 is affirmative, that is, if it is determined that the accelerator returning operation has been performed, in S4, The constant pressure standby pressure of the brake B1 is set to a hydraulic pressure _PWB higher than the constant pressure standby pressure _{PWA in the} prior art, the gradient of the sweep control is set to a gentler gradient than the conventional technology, and the hydraulic control of the brake B1 is performed. In step S5, it is determined in S5 that the shift from the second speed gear stage “2nd” to the first speed gear stage “1st” in the automatic transmission 10 is completed. This routine is terminated. In the above control, S1 is the operation of the shift determination unit 60, S3 to S5 are the operation of the shift control unit 62, S4 is the operation of the release side hydraulic pressure correction unit 64, and S2 is the accelerator operation amount determination unit. This corresponds to 66 operations.

  As described above, according to this embodiment, the first gear stage in the automatic transmission 10 that is output during the depression operation of the accelerator pedal 44 is released from the first gear stage having a larger gear ratio than the first gear stage. In the power-on downshift to the second gear stage established by releasing the side engagement element and engaging the one-way clutch F1, the accelerator pedal 44 is returned during the power-on downshift. In this case, since the hydraulic pressure higher than the hydraulic pressure corresponding to the accelerator operation amount after the return operation when the return operation is not performed is supplied to the disengagement side engagement element, it corresponds to the accelerator operation. Even when there is a delay in engine torque change, the hydraulic pressure supplied to the disengagement side engagement element is set higher than when the accelerator return operation is not performed. Improve the engagement control of the release-side engagement element can be appropriately suppressed and the occurrence of speed change shock. That is, it is possible to provide a hydraulic control device for the vehicle automatic transmission 10 that suppresses a shift shock during a power-on downshift.

Further, when the return operation of the accelerator pedal 44 is performed during the power-on downshift, the hydraulic pressure P is higher than the hydraulic pressure corresponding to the accelerator operation amount after the return operation when the return operation is not performed. _{Since the} hydraulic pressure supplied to the disengagement-side engagement element is kept at a constant pressure in _WB , even when there is a delay in the change in engine torque in response to the accelerator operation, Since the supply hydraulic pressure is kept at a constant pressure at a higher hydraulic pressure _PWB than when the accelerator return operation is not performed, the engagement controllability of the disengagement side engagement element is improved and the occurrence of a shift shock is preferably suppressed. Can do.

  Further, when the return operation of the accelerator pedal 44 is performed during the power-on downshift, the gradual decrease gradient of the hydraulic pressure corresponding to the accelerator operation amount after the return operation when the return operation is not performed. Since the supply hydraulic pressure to the disengagement side engagement element is gradually reduced at a gentle gradient, even if there is a delay in the change in engine torque corresponding to the accelerator operation, the supply to the disengagement side engagement element Since the hydraulic pressure is gradually decreased (sweep control) with a gentler slope than when the accelerator return operation is not performed, the engagement controllability of the disengagement side engagement element is improved, and the occurrence of shift shock is suitably suppressed. Can do.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention. Is.

  10: automatic transmission for vehicle, 44: accelerator pedal, 50: electronic control unit, B1, B2: brake (engagement element), C1 to C3: clutch (engagement element), F1: one-way clutch

Claims (3)

A step having a one-way clutch and a plurality of hydraulic engagement elements, and selectively establishing one of a plurality of shift stages according to a combination of engagement and release of each of the one-way clutch and the plurality of engagement elements. A hydraulic control device for an automatic transmission for a vehicle that controls a hydraulic pressure supplied to the hydraulic engagement element on the basis of an accelerator pedal operation amount;
It is established by the release of the disengagement-side engagement element and the engagement of the one-way clutch, which have a gear ratio larger than that of the first gear stage, from the first gear stage in the automatic transmission by the operation of the accelerator pedal. In the power-on downshift to the second gear stage, when the accelerator pedal is returned during the power-on downshift, the accelerator operation after the return operation when the return operation is not performed A hydraulic control device for an automatic transmission for a vehicle, wherein a hydraulic pressure higher than a hydraulic pressure corresponding to an amount is supplied to the disengagement side engagement element.   When a return operation of the accelerator pedal is performed during the power-on downshift, the hydraulic pressure is higher than the hydraulic pressure corresponding to the accelerator operation amount after the return operation when the return operation is not performed. 2. The hydraulic control device for an automatic transmission for a vehicle according to claim 1, wherein the hydraulic pressure supplied to the disengagement side engagement element is kept at a constant pressure.   When a return operation of the accelerator pedal is performed during the power-on downshift, the slope is gentler than the gradually decreasing gradient of the hydraulic pressure corresponding to the accelerator operation amount after the return operation when the return operation is not performed. 3. The hydraulic control device for an automatic transmission for a vehicle according to claim 1, wherein the hydraulic pressure supplied to the disengagement side engagement element is gradually reduced.

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