JP4826813B2 - Control device for automatic transmission - Google Patents

Description

  The present invention relates to a control device for an automatic transmission that controls a hydraulic pressure applied to a piston of a friction engagement element to switch a gear position of a transmission mechanism.

  In an automatic transmission for an automobile, the driving force of an engine is transmitted to an input shaft of a transmission mechanism via a torque converter, and the transmission is shifted by this transmission mechanism and transmitted to an output shaft to rotationally drive driving wheels. . In general, a speed change mechanism has a plurality of gears arranged between an input shaft and an output shaft to form a plurality of power transmission paths having different speed ratios between the input shaft and the output shaft. Friction engagement elements such as clutches and brakes are provided on the actuator and the engagement and release of each friction engagement element is selected by individually controlling the hydraulic pressure applied to the piston of each friction engagement element in response to a shift request. Are switched, and the power transmission path between the input and output shafts is switched to switch the gear position (gear ratio).

  In such a shift control of an automatic transmission, as described in Patent Document 1 (Japanese Patent Publication No. 5-59294), an engagement clutch that switches to an engaged state is controlled during shift control. By performing precharge control (rapid filling control) that maximizes the amount of supply control oil, the position where the piston of the engagement side clutch presses the clutch plate and the engagement side clutch begins to engage (end position of the invalid stroke) ) To move the piston in a short time. At that time, when the hydraulic switch detects that the hydraulic pressure supplied to the engagement side clutch is equal to or higher than the predetermined hydraulic pressure, it is determined that the piston of the engagement side clutch has moved to the end position of the invalid stroke, The charge control is terminated.

  By the way, when the temperature of the hydraulic oil is low and the viscosity of the hydraulic oil is relatively high, such as immediately after a cold start or during warm-up, the hydraulic fluid supplied to the engagement side clutch is reduced because the fluidity of the hydraulic oil decreases. The flow rate of hydraulic fluid supplied to the piston chamber due to the flow resistance of hydraulic fluid generated between the hydraulic pressure detection position and the piston of the engaging clutch even if it is detected by the hydraulic switch that the oil pressure exceeds the predetermined hydraulic pressure There is a possibility that (the hydraulic pressure acting on the piston) decreases and the piston cannot move to the end position of the invalid stroke.

As a countermeasure, an oil temperature sensor is provided in the hydraulic control circuit of the automatic transmission, and the precharge control execution time and the command oil pressure are set according to the oil temperature (the temperature of the hydraulic oil) detected by the oil temperature sensor. In some cases, the lower the oil temperature, the larger the amount of hydraulic oil supplied to the engagement frictional engagement element during precharge control (so-called precharge amount).
Japanese Patent Publication No. 5-59294

  However, immediately after a cold start or during warm-up, the temperature of the hydraulic control circuit, each frictional engagement element, and the piping connecting them varies depending on each part, so an oil temperature sensor provided in one place of the hydraulic control circuit The detected oil temperature does not necessarily coincide with the temperature of the hydraulic oil supplied to the engagement side frictional engagement element that actually performs the precharge control. Therefore, even if the precharge control execution time and the command oil pressure are set according to the oil temperature detected by the oil temperature sensor provided in the oil pressure control circuit, the precharge control execution time and the command oil pressure are set to appropriate values. The precharge amount may be insufficient and the speed change response may be delayed, or the precharge amount may be excessive and a shock may occur due to sudden engagement of the friction engagement element. There is.

  The present invention has been made in consideration of such circumstances. Therefore, the object of the present invention is to set the execution time of the precharge control to an appropriate time and execute the precharge control with high accuracy. An object of the present invention is to provide a control device for an automatic transmission.

  In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that the engagement of each friction engagement element is controlled by individually controlling the hydraulic pressure applied to the pistons of the plurality of friction engagement elements provided in the transmission mechanism. Shift control means for selectively switching release to switch the speed stage of the speed change mechanism is provided, and the shift control means is configured to disengage the piston of the frictional engagement element on the engagement side that is switched to the engagement state during the shift control. The automatic transmission is configured to output a hydraulic pressure command so as to move the friction engagement element to a position where the friction engagement element starts to be engaged, and to perform precharge control for filling the friction engagement element on the engagement side with hydraulic oil. In the control device, pressure detecting means provided to operate in accordance with the hydraulic pressure in the hydraulic circuit is provided in the hydraulic circuit of the engagement side frictional engagement element that switches to the engaged state at least during predetermined shift control. Provided, the shift control means In the precharge control of the engagement side frictional engagement element that switches to the engagement state during the gear shift control, the output signal of the pressure detection means provided in the hydraulic circuit of the engagement side frictional engagement element Based on this, it is detected that the hydraulic pressure in the hydraulic circuit of the friction engagement element on the engagement side has increased to a predetermined pressure, and from the start of precharge control of the friction engagement element on the engagement side, An elapsed time until the hydraulic pressure in the hydraulic circuit of the friction engagement element rises to a predetermined pressure (hereinafter referred to as “pressure rise time”) is obtained, and the pre-setting of the friction engagement element on the engagement side is determined according to the pressure rise time. The end timing of charge control is set.

  Depending on the state of hydraulic oil (temperature, fluidity, etc.) in the hydraulic circuit of the engagement side frictional engagement element, the pressure rise time (from the start of precharge control of the engagement side frictional engagement element to the friction on the engagement side) The elapsed time until the hydraulic pressure in the hydraulic circuit of the engagement element rises to a predetermined pressure), the pressure rise time reflects the state of the hydraulic oil in the hydraulic circuit of the friction engagement element on the engagement side Information. Therefore, if the end timing of the precharge control of the friction engagement element on the engagement side is set according to the pressure rise time as in the present invention, the execution time of the precharge control is set to the time of the friction engagement element on the engagement side. It can be set to an appropriate value according to the state of the hydraulic oil in the hydraulic circuit. As a result, it is possible to prevent occurrence of excess or deficiency in the precharge amount (the amount of hydraulic oil supplied to the engagement-side frictional engagement element during precharge control), and execute the precharge control with high accuracy. be able to.

  In this case, as the pressure detection means, a hydraulic sensor whose output signal continuously changes according to the hydraulic pressure in the hydraulic circuit of the frictional engagement element on the engagement side may be used. As the pressure detection means, a hydraulic switch that switches the output signal when the hydraulic pressure in the hydraulic circuit of the friction engagement element on the engagement side becomes equal to or higher than a predetermined pressure may be used. In this way, the system can be configured using a hydraulic switch that is less expensive than the hydraulic sensor, and the cost reduction requirement can be satisfied.

  When setting the end timing of the precharge control, the time from the start to the end of the precharge control of the frictional engagement element on the engagement side becomes longer as the pressure increase time becomes longer. It is preferable to set the end timing of the precharge control. In this way, the hydraulic fluid in the hydraulic circuit of the engagement-side frictional engagement element decreases as the fluidity of the hydraulic oil in the hydraulic circuit of the engagement-side frictional engagement element decreases and the pressure rise time becomes longer. In response to a decrease in the flow rate of hydraulic oil supplied to the piston chamber due to the flow resistance of the precharge control, the precharge control execution time can be extended to ensure an appropriate precharge amount. The time can be accurately set to an appropriate time.

  Generally, the shift control is performed by combining release hydraulic control of the release side frictional engagement element and engagement hydraulic control of the engagement side frictional engagement element. Therefore, at least the predetermined shift control as in claim 4 is performed. The hydraulic circuit of the disengagement side frictional engagement element that switches to the disengaged state at the time is provided with pressure detecting means provided to operate according to the hydraulic pressure in the hydraulic circuit, and is engaged during predetermined shift control. In the precharge control of the engagement side frictional engagement element to be switched to the state, the engagement side frictional engagement element is based on the output signal of the pressure detection means provided in the hydraulic circuit of the release side frictional engagement element The end timing of the precharge control may be set.

  During the shift control, the behavior of the hydraulic pressure in the hydraulic circuit of the release side frictional engagement element reflects the state of the hydraulic oil (temperature, fluidity, etc.) in the hydraulic circuit of the release side frictional engagement element. In addition, the information reflects the state of the hydraulic oil in the hydraulic circuit of the engagement side frictional engagement element. Therefore, if the end timing of the precharge control of the engagement side frictional engagement element is set based on the output signal of the pressure detecting means provided in the hydraulic circuit of the release side frictional engagement element, the precharge control is executed. The time can be set to an appropriate value according to the state of the hydraulic oil in the hydraulic circuit of the friction engagement element on the engagement side. Thereby, it is possible to prevent the precharge amount from being excessive or insufficient, and to perform the precharge control with high accuracy. Further, when the release hydraulic pressure control of the release side frictional engagement element is started before the precharge control of the engagement side frictional engagement element, the engagement side frictional engagement element is released earlier. It is possible to set the end timing of the precharge control.

  Specifically, as in the fifth aspect of the present invention, based on the output signal of the pressure detection means provided in the hydraulic circuit of the disengagement side frictional engagement element during the precharge control of the engagement side frictional engagement element. And detecting that the hydraulic pressure in the hydraulic circuit of the release side frictional engagement element has dropped to a predetermined pressure, and starting the release hydraulic control of the release side frictional engagement element, the release side frictional engagement element The elapsed time until the hydraulic pressure in the hydraulic circuit drops to a predetermined pressure (hereinafter referred to as “pressure drop time”) is determined, and the end timing of precharge control of the frictional engagement element on the engagement side according to the pressure drop time It is better to set.

  The pressure drop time (the elapsed time from the start of release hydraulic control of the release side frictional engagement element to the time when the hydraulic pressure in the hydraulic circuit of the release side frictional engagement element reaches a predetermined pressure) Since the information reflects the state of the hydraulic fluid in the hydraulic circuit of the combined element, if the end timing of the precharge control of the frictional engagement element on the engagement side is set according to this pressure drop time, the precharge control The execution time can be set to an appropriate time according to the state of the hydraulic oil in the hydraulic circuit of the engagement side frictional engagement element.

  In this case, as the pressure detection means, a hydraulic sensor whose output signal changes according to the hydraulic pressure in the hydraulic circuit of the release side frictional engagement element may be used. As an alternative, a hydraulic switch that switches the output signal when the hydraulic pressure in the hydraulic circuit of the disengagement side frictional engagement element falls below a predetermined pressure may be used. In this way, the system can be configured using a hydraulic switch that is less expensive than the hydraulic sensor, and the cost reduction requirement can be satisfied.

  When setting the end timing of the precharge control, the time from the start to the end of the precharge control of the frictional engagement element on the engagement side becomes longer as the pressure drop time becomes longer. It is preferable to set the end timing of the precharge control. In this way, as the fluidity of the hydraulic fluid in the hydraulic circuit of the release side frictional engagement element decreases and the pressure drop time becomes longer, the hydraulic fluid in the hydraulic circuit of the engagement side frictional engagement element becomes longer. Corresponding to the decrease in the flow rate of hydraulic oil supplied to the piston chamber due to flow resistance, the precharge control execution time can be lengthened to ensure an appropriate precharge amount. Can be accurately set to an appropriate time.

  Further, the control for setting the end timing of the precharge control of the frictional engagement element on the engagement side is executed based on the output signal of the pressure detecting means when the temperature of the hydraulic oil is not more than a predetermined value. It is good to do. In this way, even when the temperature of the hydraulic oil is lower than a predetermined value and the fluidity of the hydraulic oil is reduced, the precharge control execution time can be set within the hydraulic circuit in the hydraulic circuit of the friction engagement element on the engagement side. It is possible to prevent occurrence of excess or deficiency in the precharge amount by setting an appropriate time according to the state.

  Several embodiments embodying the best mode for carrying out the present invention will be described below.

A first embodiment of the present invention will be described with reference to FIGS.
First, a schematic configuration of the automatic transmission 11 will be described with reference to FIG.
An input shaft 15 of a torque converter 14 is connected to the output shaft 13 of the engine 12 which is an internal combustion engine, and a hydraulically driven transmission gear mechanism 17 (transmission mechanism) is connected to the output shaft 16 of the torque converter 14. Yes. Inside the torque converter 14, a pump impeller 18 and a turbine runner 19 constituting a fluid coupling are provided facing each other, and a stator 20 that rectifies the flow of oil is provided between the pump impeller 18 and the turbine runner 19. It has been. The pump impeller 18 is connected to the input shaft 15 of the torque converter 14, and the turbine runner 19 is connected to the output shaft 16 of the torque converter 14.

  The torque converter 14 is provided with a lockup clutch 21 for engaging or disengaging between the input shaft 15 side and the output shaft 16 side. The output torque of the engine 12 is transmitted to the transmission gear mechanism 17 via the torque converter 14 and is shifted by the first to third planetary gear mechanisms 22 to 24 of the transmission gear mechanism 17 so as to drive the vehicle (front wheels or front wheels). It is transmitted to the rear wheel.

  The transmission gear mechanism 17 is provided with a plurality of clutches C0, C1, C2 and a plurality of brakes B0, B1, B2 which are friction engagement elements for switching a plurality of shift stages, and a plurality of one-way clutches F0. , F1 are provided. As shown in FIG. 3, the clutches C0, C1, C2 and brakes B0, B1, B2 are engaged / released hydraulically to change the gear combinations of the planetary gear mechanisms 22-24 that transmit power. The gear ratio is switched by switching.

  FIG. 3 shows the combination of engagement of the clutches C0, C1, C2 and the brakes B0, B1, B2 of the 5-speed automatic transmission. The circles indicate the engagement state (torque transmission state) at that gear stage. A clutch and a brake to be held are shown, and no mark indicates a released state. For example, when the shift lever 30 is operated from the N range to the D range and the transmission gear mechanism 17 is switched from the neutral state to the first speed, C1 is released from the engagement of C1 and B1, and B2 is newly engaged. . In the throttle depression state of the D range, as the vehicle speed increases, the first speed, the second speed, the third speed, the fourth speed, and the fifth speed are upshifted. In the shift from the first speed to the second speed, C2 is newly engaged from the engagement of B1 and B2. In the shift from the second speed to the third speed, B2 is released from the engagement of C2, B1, and B2, and C1 is newly engaged. In the shift from the third speed to the fourth speed, B1 is released from the engagement of C1, C2, and B1, and C0 is newly engaged. In the shift from the fourth speed to the fifth speed, C2 is released from the engagement of C0, C1, and C2, and B1 is newly engaged.

  As shown in FIG. 1, the transmission gear mechanism 17 is provided with a hydraulic pump (not shown) driven by engine power, and in an oil pan (not shown) for storing hydraulic oil (oil), A hydraulic control circuit 25 is provided. The hydraulic control circuit 25 includes a line pressure control circuit 26, an automatic transmission control circuit 27, a lock-up control circuit 28, a manual switching valve 29, and the like. The hydraulic oil pumped up from the oil pan by a hydraulic pump is a line pressure control circuit. The automatic transmission control circuit 27 and the lockup control circuit 28 are supplied to the automatic transmission control circuit 27. The line pressure control circuit 26 is provided with a line pressure control hydraulic control valve (not shown) for controlling the hydraulic pressure from the hydraulic pump to a predetermined line pressure, and the automatic transmission control circuit 27 includes the transmission gear mechanism 17. A plurality of shift control hydraulic control valves 37 to 41 (see FIG. 2) for controlling the hydraulic pressure supplied to the clutches C0, C1, C2 and the brakes B0, B1, B2. The lockup control circuit 28 is provided with a lockup control hydraulic control valve (not shown) for controlling the hydraulic pressure supplied to the lockup clutch 21.

  Further, a manual switching valve 29 that is switched in conjunction with the operation of the shift lever 30 is provided between the line pressure control circuit 26 and the automatic transmission control circuit 27. When the shift lever 30 is operated to the neutral range (N range) or the parking range (P range), the energization of the hydraulic control valves 37 to 41 of the automatic transmission control circuit 27 is stopped (OFF). However, the hydraulic pressure supplied to the transmission gear mechanism 17 by the manual switching valve 29 is switched so that the transmission gear mechanism 17 is in the neutral state.

  On the other hand, the engine 12 is provided with a throttle opening sensor 31 for detecting the throttle opening. The transmission gear mechanism 17 includes a rotation speed sensor 32 that detects the rotation speed of the sun gear 22a of the first planetary gear mechanism 22, a rotation speed sensor 33 that detects the rotation speed of the carrier 22b of the planetary gear mechanism 22, An output shaft rotation speed sensor 35 that detects the rotation speed of the output shaft 34 of the transmission gear mechanism 17 is provided. An oil temperature sensor 53 that detects the temperature of the hydraulic oil is provided at a predetermined location of the hydraulic control circuit 25.

  As shown in FIG. 2, the automatic transmission control circuit 27 is provided with hydraulic control valves 37 to 39 for controlling the hydraulic pressure to be supplied for each of the clutches C0 to C2, and for each of the brakes B1 and B2. In addition, hydraulic control valves 40 and 41 for controlling the hydraulic pressure to be supplied are provided. In the hydraulic control valves 37 to 41, the direct acting valves 37b to 41b are driven in the valve opening direction (or valve closing direction) by solenoids 37a to 41a, and when the energization of the solenoids 37a to 41a is stopped, the direct acting valves are driven by springs 37c to 41c. 37b to 41b are held in the valve closing position (or valve opening position).

  In addition, hydraulic switches 42 to 44 (pressure detection means) are provided between the clutches C0 to C2 and the hydraulic control valves 37 to 39 in the hydraulic circuits of the clutches C0 to C2, respectively, and the brakes B1. , B2 are provided with hydraulic switches 45, 46 (pressure detecting means) between the brakes B1, B2 and the hydraulic control valves 40, 41, respectively. Each of the hydraulic switches 42 to 46 switches the output signal from OFF to ON when the hydraulic pressure in the hydraulic circuit (the hydraulic pressure supplied to the clutch or brake) exceeds a predetermined pressure, and the hydraulic pressure in the hydraulic circuit is set to the predetermined pressure. The output signal is switched from on to off when it becomes less than the value.

  Output signals from the various sensors and switches described above are input to an automatic transmission electronic control circuit (hereinafter referred to as “AT-ECU”) 36. The AT-ECU 36 is mainly composed of a microcomputer, and executes each speed change control program stored in a built-in ROM (storage medium), whereby the speed change gear mechanism 17 shifts according to a preset speed change pattern. Each of the automatic shift control circuit 27 is set in response to a shift speed change request (target shift speed change request) generated according to the operating position of the shift lever 30 and the driving conditions (throttle opening, vehicle speed, etc.). By controlling the energization to the hydraulic control valves 37 to 41 and controlling the hydraulic pressure applied to the clutches C0 to C2 and the brakes B0 to B2 of the transmission gear mechanism 17, as shown in FIG. Switch the combination of the gears of the planetary gear mechanisms 22 to 24 that transmit power by switching the engagement / release of the brakes B0 to B2 In Rukoto switches the transmission ratio of the transmission gear mechanism 17.

  As shown in FIG. 4, each of the clutches C <b> 0 to C <b> 2 and the respective brakes B <b> 0 to B <b> 2 is an operation in which the piston 49 is movably provided in the piston chamber 48 formed in the drum 47 and the piston chamber 48 is filled. The oil pressure rises and the piston 49 moves in the engagement direction (right direction in FIG. 4) due to the oil pressure, so that the engaged state is established. At that time, when the piston 49 presses the metal plate 50 and moves to a position where frictional force starts to be generated between the metal plate 50 and the friction plate 51, the clutch (or brake) starts to be engaged. The position where the clutch (or brake) starts to be engaged is the end position of the invalid stroke of the piston 49. On the other hand, the hydraulic pressure in the piston chamber 48 is reduced, and the piston 49 moves to the release direction (leftward in FIG. 4) by the urging force of the return spring 52, so that the release state is achieved.

Hereinafter, the shift control when the shift lever 30 is operated from the N range to the D range and the transmission gear mechanism 17 is switched from the neutral state to the first speed will be described.
When the transmission gear mechanism 17 is switched from the neutral state to the first speed, the hydraulic oil is discharged from the clutch C1 and the release hydraulic pressure control for switching the clutch C1 from the engaged state to the released state is executed, and the hydraulic oil is supplied to the brake B2. Engagement hydraulic control is performed to fill and switch the brake B2 from the released state to the engaged state.

  As shown in FIG. 5, in the engagement hydraulic pressure control of the brake B2, precharge control (also referred to as rapid charging control) is executed at a time point t0 when the target shift speed is switched to the first speed. In the precharge control of the brake B2, the brake B2 is engaged with the piston 49 of the brake B2 by setting the hydraulic pressure command value of the brake B2 to a predetermined precharge hydraulic pressure and rapidly filling the brake B2 with hydraulic fluid. Move to the start position (end position of invalid stroke) in a short time.

  In the first embodiment, during the precharge control of the brake B2, if the temperature of the hydraulic oil is equal to or lower than a predetermined value (when the fluidity of the hydraulic oil is lowered), the precharge control of the brake B2 is performed. After the start, the hydraulic pressure in the hydraulic circuit of the brake B2 increases to a predetermined pressure (pressure lower than the precharge hydraulic pressure), and the output of the hydraulic switch 46 for the brake B2 (the hydraulic switch provided in the hydraulic circuit of the brake B2) At time t1 when the signal is switched from OFF to ON, the elapsed time from the start of the precharge control of the brake B2 to the increase in the hydraulic pressure in the hydraulic circuit of the brake B2 is obtained as the pressure increase time Ta.

The precharge control remaining time ΔT is calculated according to the pressure increase time Ta, and the precharge control remaining time ΔT is added to the pressure increase time Ta to execute the precharge control execution time Tb (from the start of the precharge control). End time), and the end timing t2 of the precharge control of the brake B2 is set.
Tb = Ta + ΔT

  Pressure rise time Ta (elapsed time from the start of the precharge control of the brake B2 until the hydraulic pressure in the hydraulic circuit of the brake B2 increases to a predetermined pressure depending on the state of the hydraulic oil (temperature, fluidity, etc.) in the hydraulic circuit of the brake B2 Therefore, the pressure rise time Ta is information reflecting the state of the hydraulic oil in the hydraulic circuit of the brake B2. Accordingly, if the end timing of the precharge control of the brake B2 is set according to the pressure increase time Ta, the execution time of the precharge control is set to an appropriate time according to the state of the hydraulic oil in the hydraulic circuit of the brake B2. be able to.

  The precharge control of the brake B2 of the first embodiment is executed by the AT-ECU 36 according to the precharge control routine of FIG. Hereinafter, processing contents of the precharge control routine of FIG. 6 will be described.

  The precharge control routine shown in FIG. 6 serves as a shift control means in the claims. When this routine is started, first, at step 101, it is determined whether or not the temperature of the hydraulic oil detected by the oil temperature sensor 53 is a predetermined value (for example, 20 ° C.) or less. In the case of a system that does not include the oil temperature sensor 53, the cooling water temperature detected by the cooling water temperature sensor, the intake air temperature detected by the intake air temperature sensor, the outside air temperature detected by the outside air temperature sensor, the elapsed time after starting the engine, etc. The temperature of the hydraulic oil may be estimated based on at least one of the above.

  If it is determined in step 101 that the temperature of the hydraulic oil is equal to or lower than a predetermined value (that is, the fluidity of the hydraulic oil is reduced), the process proceeds to step 102 and the elapsed time after the start of precharge control. After resetting the count value of the elapsed time counter T that counts to “0” and resetting the pressure increase determination flag Fa to “0”, the routine proceeds to step 103 where the hydraulic pressure command value of the brake B2 is set to a predetermined precharge hydraulic pressure. To start precharge control.

  Thereafter, the routine proceeds to step 104, where it is determined whether or not the pressure increase determination flag Fa is set to “1”, and when it is determined that the pressure increase determination flag Fa is still “0”, step 105 is performed. Then, it is determined whether or not the output signal of the hydraulic switch 46 for the brake B2 (hydraulic switch provided in the hydraulic circuit of the brake B2) is turned on.

  If it is determined in step 105 that the hydraulic switch 46 for the brake B2 is still OFF, the process proceeds to step 110, and the count value of the elapsed time counter T is incremented by “1”. After waiting for a predetermined time (for example, 10 msec), the process returns to step 103.

  Thereafter, when the hydraulic pressure in the hydraulic circuit of the brake B2 rises to a predetermined pressure and it is determined in step 105 that the hydraulic switch 46 for the brake B2 is turned on, the process proceeds to step 106, and the pressure increase determination flag After setting Fa to "1", the routine proceeds to step 107, where the count value of the elapsed time counter T (that is, from the start of the precharge control of the brake B2 until the hydraulic pressure in the hydraulic circuit of the brake B2 rises to a predetermined pressure) Is set as the pressure rise time Ta.

Thereafter, the routine proceeds to step 108, where the precharge control remaining time ΔT corresponding to the pressure rise time Ta is calculated with reference to the map of the remaining precharge control time ΔT shown in FIG. 7, and the precharge control is performed at the pressure rise time Ta. The remaining time ΔT is added to determine the precharge control execution time Tb (time from the start to the end of the precharge control).
Tb = Ta + ΔT

  Here, the precharge control remaining time ΔT shown in FIG. 7 is set so that the precharge control remaining time ΔT becomes longer and the precharge control execution time Tb becomes longer as the pressure increase time Ta becomes longer. . As a result, as the fluidity of the hydraulic oil in the hydraulic circuit of the brake B2 decreases and the pressure rise time Ta becomes longer, the hydraulic oil supplied to the piston chamber 48 by the flow resistance of the hydraulic oil in the hydraulic circuit of the brake B2 becomes longer. Corresponding to the decrease in flow rate, the precharge control execution time Tb can be lengthened to ensure an appropriate precharge amount (the amount of hydraulic oil supplied to the brake B2 during precharge control). The execution time Tb of the precharge control can be accurately set to an appropriate time.

  In step 108, the precharge control remaining time ΔT corresponding to the pressure rise time Ta is calculated from a map, and the precharge control remaining time ΔT is added to the pressure rise time Ta to obtain the precharge control execution time Tb. However, the execution time Tb of the precharge control corresponding to the pressure increase time Ta may be directly calculated from the map.

  Thereafter, the process proceeds to step 109, where it is determined whether or not the count value of the elapsed time counter T is equal to or longer than the execution time Tb of the precharge control, and the count value of the elapsed time counter T reaches the execution time Tb of the precharge control. If not, the count value of the elapsed time counter T is counted up and after waiting for a predetermined time (steps 110 and 111), the process returns to step 103.

  After the hydraulic switch 46 for the brake B2 is turned on and the pressure increase determination flag Fa is set to “1”, it is determined in step 104 that the pressure increase determination flag Fa is set to “1”. In step 109, it is determined whether or not the count value of the elapsed time counter T is equal to or greater than the execution time Tb of the precharge control, and the count value of the elapsed time counter T has not reached the execution time Tb of the precharge control. For example, after counting up the count value of the elapsed time counter T and waiting for a predetermined time (steps 110 and 111), the process returns to step 103.

  Thereafter, when it is determined in step 109 that the count value of the elapsed time counter T is equal to or longer than the execution time Tb of the precharge control, it is determined that the precharge control is finished, the process proceeds to step 113, and the brake The hydraulic pressure command value of B2 is set to a predetermined standby hydraulic pressure and the precharge control is finished.

  It should be noted that the process of calculating the precharge control execution time Tb is omitted, and from the time when the hydraulic switch 46 for the brake B2 is turned on (the time when the hydraulic pressure in the hydraulic circuit of the brake B2 rises to a predetermined pressure). When the remaining precharge control time ΔT has elapsed, it may be determined that it is the end timing of the precharge control.

  On the other hand, if it is determined in step 101 that the temperature of the hydraulic oil is higher than a predetermined value, the process proceeds to step 112 and normal precharge control is executed. In this normal precharge control, the hydraulic pressure command value of the brake B2 is set to a predetermined precharge hydraulic pressure to start the precharge control, and after a predetermined time has elapsed from the start of the precharge control, the process proceeds to step 113. Then, the hydraulic pressure command value of the brake B2 is set to a predetermined standby hydraulic pressure, and the precharge control is finished.

  In the first embodiment described above, when the temperature of the hydraulic oil is equal to or lower than a predetermined value during the precharge control of the brake B2, the precharge of the brake B2 is performed based on the output signal of the hydraulic switch 46 for the brake B2. The elapsed time from the start of control until the hydraulic pressure in the hydraulic circuit of the brake B2 rises to a predetermined pressure is obtained as the pressure rising time Ta, and this pressure rising time Ta (the state of the hydraulic oil in the hydraulic circuit of the brake B2 is reflected) Since the execution time Tb of the precharge control of the brake B2 is calculated according to the information) and the end timing of the precharge control of the brake B2 is set, the execution time Tb of the precharge control is set as the hydraulic circuit of the brake B2. It can be set to an appropriate time according to the state of the hydraulic oil inside. As a result, even when the temperature of the hydraulic oil is below a predetermined value and the fluidity of the hydraulic oil is reduced, it is possible to prevent the precharge amount from being excessive or insufficient, and to perform the precharge control with high accuracy. it can.

  In the first embodiment, since the hydraulic switch 46 is used as the pressure detecting means for detecting that the hydraulic pressure in the hydraulic circuit of the brake B2 has increased to a predetermined pressure, the output signal changes according to the hydraulic pressure. The system can be configured using the hydraulic switch 46 that is less expensive than the hydraulic sensor, and the cost reduction requirement can be satisfied.

  However, the present invention is not limited to the configuration using the hydraulic switch 46, and a configuration using a hydraulic sensor instead of the hydraulic switch 46 may be used.

Next, Embodiment 2 of the present invention will be described with reference to FIGS.
As described above, when the transmission gear mechanism 17 is switched from the neutral state to the first speed, the hydraulic oil is discharged from the clutch C1 and the release hydraulic pressure control for switching the clutch C1 from the engaged state to the released state is executed, and the brake is applied. Engagement hydraulic control is performed to fill B2 with hydraulic oil and switch the brake B2 from the released state to the engaged state.

  As shown in FIG. 8, in the release hydraulic pressure control of the clutch C1, the hydraulic pressure command value of the clutch C1 is set to a predetermined release hydraulic pressure (for example, approximately 0) at the time t0 when the target shift speed is switched to the first speed. On the other hand, in the engagement hydraulic pressure control of the brake B2, the precharge control is executed by setting the hydraulic pressure command value of the brake B2 to a predetermined precharge hydraulic pressure at the time point t0 when the target shift speed is switched to the first speed.

  In the second embodiment, during the precharge control of the brake B2, if the temperature of the hydraulic oil is equal to or lower than a predetermined value (when the fluidity of the hydraulic oil is reduced), the release hydraulic pressure control of the clutch C1 and After the engagement hydraulic pressure control (precharge control) of the brake B2 is started, the hydraulic pressure in the hydraulic circuit of the clutch C1 drops to a predetermined pressure (for example, a pressure higher than the release hydraulic pressure), and the hydraulic switch 43 for the clutch C1 (clutch From the start of the release hydraulic control of the clutch C1 until the hydraulic pressure in the hydraulic circuit of the clutch C1 drops to a predetermined pressure at the time t3 when the output signal of the hydraulic switch provided in the hydraulic circuit of C1 switches from on to off. Is determined as the pressure drop time Tc.

The precharge control remaining time ΔT is calculated according to the pressure drop time Tc, and the precharge control remaining time ΔT is added to the pressure drop time Tc to execute the precharge control execution time Td (from the start of the precharge control). End time), and the end timing t4 of the precharge control of the brake B2 is set.
Td = Tc + ΔT

  In this case, the pressure drop time Tc (the elapsed time from the start of the release hydraulic control of the clutch C1 until the hydraulic pressure in the hydraulic circuit of the clutch C1 drops to a predetermined pressure) is the state of the hydraulic oil in the hydraulic circuit of the clutch C1 ( Temperature, fluidity, etc.), and further information reflecting the state of the hydraulic oil in the hydraulic circuit of the brake B2. Accordingly, by setting the end timing of the precharge control of the brake B2 according to the pressure drop time Tc, the execution time of the precharge control is set to an appropriate time according to the state of the hydraulic oil in the hydraulic circuit of the brake B2. can do.

  The precharge control of the brake B2 of the second embodiment is executed by the AT-ECU 36 according to the precharge control routine of FIG.

  When the precharge control routine shown in FIG. 9 is started, first, in step 201, it is determined whether or not the temperature of the hydraulic oil is equal to or lower than a predetermined value. If it is determined in step 201 that the temperature of the hydraulic oil is equal to or lower than a predetermined value (that is, the fluidity of the hydraulic oil is lowered), the process proceeds to step 202 and the count value of the elapsed time counter T is set. After resetting to “0” and resetting the pressure drop determination flag Fb to “0”, the routine proceeds to step 203 where the hydraulic pressure command value of the brake B2 is set to a predetermined precharge hydraulic pressure and precharge control is started. At this time, a release hydraulic pressure control routine (not shown) sets the hydraulic pressure command value of the clutch C1 to a predetermined release hydraulic pressure, and the release hydraulic pressure control of the clutch C1 is started.

  Thereafter, the process proceeds to step 204, where it is determined whether or not the pressure drop determination flag Fb is set to “1”. If it is determined that the pressure drop determination flag Fb is still “0”, step 205 Then, it is determined whether or not the output signal of the hydraulic switch 43 for the clutch C1 (hydraulic switch provided in the hydraulic circuit of the clutch C1) is turned off.

  If it is determined in step 205 that the hydraulic switch 43 for the clutch C1 is still on, the process proceeds to step 210, the count value of the elapsed time counter T is incremented by “1”, and then in step 211. After waiting for a predetermined time (for example, 10 msec), the process returns to step 203.

  After that, when the hydraulic pressure in the hydraulic circuit of the clutch C1 drops to a predetermined pressure and it is determined in step 205 that the hydraulic switch 43 for the clutch C1 is switched off, the process proceeds to step 206, where the pressure drop determination flag After setting Fb to “1”, the routine proceeds to step 207, where the current elapsed time counter T count value (that is, from the start of the release hydraulic control of the clutch C1 until the hydraulic pressure in the hydraulic circuit of the clutch C1 drops to a predetermined pressure) Is set as the pressure drop time Tc.

Thereafter, the routine proceeds to step 208, where the precharge control remaining time ΔT corresponding to the pressure drop time Tc is calculated with reference to the map of the remaining precharge control time ΔT shown in FIG. 10, and the precharge control is performed at the pressure drop time Tc. The remaining time ΔT is added to determine the precharge control execution time Td (the time from the start to the end of the precharge control).
Td = Tc + ΔT

  The map of the remaining precharge control time ΔT shown in FIG. 10 is set so that the longer the pressure drop time Tc, the longer the remaining precharge control time ΔT and the longer the precharge control execution time Td. As a result, as the fluidity of the hydraulic oil in the hydraulic circuit of the clutch C1 decreases and the pressure drop time Tc increases, the hydraulic oil supplied to the piston chamber 48 by the flow resistance of the hydraulic oil in the hydraulic circuit of the brake B2 increases. In response to the decrease in the flow rate, the precharge control execution time Td can be lengthened to ensure an appropriate precharge amount (the amount of hydraulic oil supplied to the brake B2 during the precharge control). The execution time Td of the precharge control can be accurately set to an appropriate time.

  In step 208, the remaining precharge control time ΔT corresponding to the pressure drop time Tc is calculated from a map, and the precharge control remaining time ΔT is added to the pressure drop time Tc to obtain the precharge control execution time Td. However, the execution time Td of the precharge control corresponding to the pressure drop time Tc may be directly calculated from the map.

  Thereafter, the process proceeds to step 209, where it is determined whether or not the count value of the elapsed time counter T is equal to or longer than the execution time Td of the precharge control, and the count value of the elapsed time counter T reaches the execution time Td of the precharge control. If not, after counting up the count value of the elapsed time counter T and waiting for a predetermined time (steps 210 and 211), the process returns to step 203.

  After the hydraulic switch 43 for the clutch C1 is turned off and the pressure drop determination flag Fb is set to “1”, it is determined in step 204 that the pressure drop determination flag Fb is set to “1”. In step 209, it is determined whether or not the count value of the elapsed time counter T has become equal to or greater than the execution time Td of the precharge control, and the count value of the elapsed time counter T must reach the execution time Td of the precharge control. For example, after counting up the count value of the elapsed time counter T and waiting for a predetermined time (steps 210 and 211), the process returns to step 203.

  Thereafter, when it is determined in step 209 that the count value of the elapsed time counter T has become equal to or longer than the execution time Td of the precharge control, it is determined that the precharge control is finished, the process proceeds to step 213, and the brake The hydraulic pressure command value of B2 is set to a predetermined standby hydraulic pressure and the precharge control is finished.

  Note that the process of calculating the precharge control execution time Td is omitted, and from the time when the hydraulic switch 43 for the clutch C1 is switched off (the time when the hydraulic pressure in the hydraulic circuit of the clutch C1 drops to a predetermined pressure). When the remaining precharge control time ΔT has elapsed, it may be determined that it is the end timing of the precharge control.

  In the second embodiment described above, when the hydraulic oil temperature is equal to or lower than a predetermined value during the precharge control of the brake B2, the release hydraulic pressure of the clutch C1 is based on the output signal of the hydraulic switch 43 for the clutch C1. The elapsed time from the start of control until the hydraulic pressure in the hydraulic circuit of the clutch C1 drops to a predetermined pressure is obtained as the pressure drop time Tc, and this pressure drop time Tc (reflects the state of the hydraulic oil in the hydraulic circuit of the brake B2). Since the execution time Td of the precharge control of the brake B2 is calculated according to the information) and the end timing of the precharge control of the brake B2 is set, the execution time Td of the precharge control is set as the hydraulic circuit of the brake B2. It can be set to an appropriate time according to the state of the hydraulic oil inside. As a result, even when the temperature of the hydraulic oil is below a predetermined value and the fluidity of the hydraulic oil is reduced, it is possible to prevent the precharge amount from being excessive or insufficient, and to perform the precharge control with high accuracy. it can. Further, when the release hydraulic pressure control of the clutch C1 is started before the precharge control of the brake B2, the end timing of the precharge control of the brake B2 can be set earlier.

  In the second embodiment, since the hydraulic switch 43 is used as the pressure detecting means for detecting that the hydraulic pressure in the hydraulic circuit of the clutch C1 has dropped to a predetermined pressure, the output signal changes according to the hydraulic pressure. The system can be configured using the hydraulic switch 43 that is less expensive than the hydraulic sensor, and the cost can be reduced.

  However, the present invention is not limited to the configuration using the hydraulic switch 43, and a configuration using a hydraulic sensor instead of the hydraulic switch 43 may be used.

  In the second embodiment, the precharge control of the brake B2 is performed according to the pressure drop time Tc (the elapsed time from the start of the release hydraulic control of the clutch C1 until the hydraulic pressure in the hydraulic circuit of the clutch C1 drops to a predetermined pressure). The execution time Td is calculated and the end timing of the precharge control of the brake B2 is set. However, the hydraulic pressure in the hydraulic circuit of the clutch C1 is reduced to a predetermined value by the hydraulic switch 43 (or a hydraulic sensor) for the clutch C1. When it is detected that the vehicle has been lowered, the precharge control of the brake B2 may be terminated.

  In the first and second embodiments, the present invention is applied to the precharge control of the brake B2, but it goes without saying that the present invention may be applied to precharge control of clutches and brakes other than the brake B2.

  In addition, the present invention can be implemented with various modifications such that it is not always necessary to provide pressure detecting means (hydraulic switch or hydraulic sensor) in the hydraulic circuit of the clutch or brake to which the precharge control of the present invention is not applied.

It is a schematic block diagram of the whole automatic transmission in Example 1 of this invention. It is a figure explaining schematic structure of an automatic transmission control circuit. It is a figure which shows the combination of engagement / release of clutch C0-C2 and brake B0-B2 for every gear stage. It is a figure explaining schematic structure of a clutch and a brake. 6 is a time chart illustrating precharge control according to the first embodiment. 4 is a flowchart for explaining a flow of processing of a precharge control routine according to the first embodiment. It is a figure which shows notionally an example of the map of precharge control remaining time (DELTA) T of Example 1. FIG. 6 is a time chart illustrating precharge control according to the second embodiment. 6 is a flowchart for explaining a flow of processing of a precharge control routine according to the second embodiment. It is a figure which shows notionally an example of the map of precharge control remaining time (DELTA) T of Example 2. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Automatic transmission, 14 ... Torque converter, 17 ... Transmission gear mechanism (transmission mechanism), 25 ... Hydraulic control circuit, 27 ... Automatic transmission control circuit, 36 ... AT-ECU (transmission control means), 37-41 ... Hydraulic pressure Control valve, 42 to 46 ... hydraulic switch (pressure detecting means), 48 ... piston chamber, 49 ... piston, 53 ... oil temperature sensor, C0 to C2 ... clutch (friction engagement element), B0 to B2 ... brake (friction engagement) Joint element)

Claims (8)

Shift that selectively switches between engagement and disengagement of each friction engagement element by individually controlling the hydraulic pressure applied to pistons of a plurality of friction engagement elements provided in the transmission mechanism Control means, and the shift control means moves the piston of the engagement-side friction engagement element that is switched to the engaged state during shift control to a position where the engagement-side friction engagement element starts to engage. In a control device for an automatic transmission that outputs a hydraulic pressure command and performs precharge control for filling the engagement frictional engagement element with hydraulic oil,
Pressure detecting means provided at least in a hydraulic circuit of an engagement-side friction engagement element that switches to an engagement state at the time of predetermined shift control, so as to operate according to the hydraulic pressure in the hydraulic circuit;
The shift control means is provided in a hydraulic circuit of the engagement-side friction engagement element during precharge control of the engagement-side friction engagement element that switches to the engagement state during the predetermined shift control. On the basis of the output signal of the pressure detection means, it is detected that the hydraulic pressure in the hydraulic circuit of the friction engagement element on the engagement side has increased to a predetermined pressure, and precharge control of the friction engagement element on the engagement side is performed. The elapsed time (hereinafter referred to as “pressure rise time”) until the hydraulic pressure in the hydraulic circuit of the engagement side frictional engagement element rises to a predetermined pressure is determined, and the engagement is performed according to the pressure rise time. A control device for an automatic transmission, wherein an end timing of precharge control of a frictional engagement element on the side is set.   2. The pressure switch according to claim 1, wherein the pressure detection unit is a hydraulic switch that switches an output signal when a hydraulic pressure in a hydraulic circuit of the engagement side frictional engagement element exceeds a predetermined pressure. Control device for automatic transmission.   The shift control means sets the end timing of the precharge control so that the time from the start to the end of the precharge control of the frictional engagement element on the engagement side becomes longer as the pressure increase time becomes longer. The control device for an automatic transmission according to claim 1 or 2, characterized in that: Shift that selectively switches between engagement and disengagement of each friction engagement element by individually controlling the hydraulic pressure applied to pistons of a plurality of friction engagement elements provided in the transmission mechanism Control means, and the shift control means moves the piston of the engagement-side friction engagement element that is switched to the engaged state during shift control to a position where the engagement-side friction engagement element starts to engage. In a control device for an automatic transmission that outputs a hydraulic pressure command and performs precharge control for filling the engagement frictional engagement element with hydraulic oil,
A pressure detection means provided in a hydraulic circuit of a disengagement friction engagement element that switches to a disengaged state at least during a predetermined shift control so as to operate according to the hydraulic pressure in the hydraulic circuit;
The shift control means is provided in the hydraulic circuit of the disengagement side frictional engagement element during precharge control of the engagement side frictional engagement element that switches to the engaged state during the predetermined shift control. An automatic transmission control device, wherein an end timing of precharge control of the frictional engagement element on the engagement side is set based on an output signal of the pressure detection means.   The shift control unit is configured to control the disengagement side based on an output signal of a pressure detection unit provided in a hydraulic circuit of the disengagement side frictional engagement element during precharge control of the engagement side frictional engagement element. It is detected that the hydraulic pressure in the hydraulic circuit of the frictional engagement element of the motor has decreased to a predetermined pressure, and from the start of the release hydraulic pressure control of the frictional engagement element on the release side, the hydraulic circuit of the frictional engagement element on the release side The elapsed time (hereinafter referred to as “pressure drop time”) until the hydraulic pressure drops to a predetermined pressure is obtained, and the end timing of the precharge control of the frictional engagement element on the engagement side is set according to the pressure drop time. The control device for an automatic transmission according to claim 4.   6. The pressure switch according to claim 4, wherein the pressure detection means is a hydraulic switch that switches an output signal when a hydraulic pressure in a hydraulic circuit of the release side frictional engagement element becomes less than a predetermined pressure. Automatic transmission control device.   The shift control means sets the end timing of the precharge control so that the time from the start to the end of the precharge control of the frictional engagement element on the engagement side becomes longer as the pressure drop time becomes longer. The control device for an automatic transmission according to any one of claims 4 to 6.   The shift control means executes control for setting the end timing of precharge control of the frictional engagement element on the engagement side based on the output signal of the pressure detection means when the temperature of the hydraulic oil is below a predetermined value. The control device for an automatic transmission according to any one of claims 1 to 7.

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