JP3948896B2 - Control device for automatic transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an automatic transmission, and more particularly to a technique for suppressing the occurrence of idling during shift control.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is known an automatic transmission configured to change gears by switching friction engagement elements that simultaneously perform fastening control and release control of two different friction engagement elements.
As a shift control device for performing the shifting shift of the friction engagement elements, for example, as disclosed in JP-A-11-030324, an oil supply path to each friction engagement element is provided with an accumulator, Some have been configured to control the gradient of hydraulic pressure rise and fall by controlling the back pressure of the accumulator.
[0003]
On the other hand, in the above-described shift control device that performs a shifting shift of the frictional engagement elements, Japanese Patent Laid-Open Nos. 7-012210, 5-039843, and 2000 are disclosed as techniques for suppressing the occurrence of idling during a shift. There are some as disclosed in Japanese Patent No. 055180.
According to the technique disclosed in Japanese Patent Application Laid-Open No. 7-012210, an increase in the hydraulic pressure of the engagement side frictional engagement element is detected by a pressure switch, and the timing for releasing the hydraulic pressure of the release side frictional engagement element is determined. Yes.
[0004]
Further, in the one disclosed in Japanese Patent Laid-Open No. 5-039843, when the slip amount of the release side frictional engagement element is equal to or greater than a threshold value, the hydraulic pressure of the release side frictional engagement element is increased while the slip amount is increased. When the rate of change of is less than or equal to 0, the hydraulic pressure of the disengagement side frictional engagement element is reduced.
Further, in the one disclosed in Japanese Patent Laid-Open No. 2000-055180, the completion of the stroke of the engagement side frictional engagement element is predicted, and the reduction of the line pressure is started by timing the completion of the stroke.
[0005]
[Problems to be solved by the invention]
However, in the configuration using the pressure switch, since the pressure switch is generally expensive, there is a problem that the system cost of the automatic transmission increases.
In the configuration in which the hydraulic pressure is controlled in accordance with the slip amount of the disengagement side frictional engagement element, the oil pressure of the disengagement side frictional engagement element is controlled and converged so as to maintain the minute slip amount, so that the shift time is extended. As a result, there is a possibility that the transmission performance is deteriorated.
[0006]
Furthermore, in the configuration in which the stroke side of the engagement side frictional engagement element is timed to start the decrease of the line pressure, the occurrence of idling cannot be stably suppressed due to a prediction error at the time of completion of the stroke, In addition, a decrease in the line pressure (original pressure) in the torque phase may reduce the response of the clutch hydraulic pressure, and may promote further idling.
[0007]
Further, as disclosed in Japanese Patent Application Laid-Open No. 11-030324, in the configuration that controls the timing of draining the accumulator back pressure of the release side frictional engagement element with reference to the accumulator back pressure of the fastening side frictional engagement element, By optimally setting the fastening-side accumulator back pressure, the release-side torque capacity can be lowered at the timing when the fastening-side torque capacity is secured. Since the oil in the hydraulic path is drained, the hydraulic pressure response on the fastening side is delayed when shifting for the first time after the start of operation, and there is a possibility that a large air blow occurs.
[0008]
The present invention has been made in view of the above problems, and in an automatic transmission that controls a back pressure of an accumulator to perform a change-over shift, it is stable without causing an increase in cost and an increase in shift time. The purpose is to be able to suppress the occurrence of air blow.
[0010]
[Means for Solving the Problems]
Therefore, according to the first aspect of the present invention, there is provided a shift solenoid that switches on / off the oil supply / discharge of each friction engagement element, and the back of the accumulator interposed in the oil supply path to each friction engagement element. Duty solenoid that controls pressure and working pressure of engagement side frictional engagement element Depending on the differential pressure between the back side and the accumulator back pressure Accumulator back pressure of release side frictional engagement element Drain A timing valve; By switching the supply / drain of the signal pressure to the timing valve, a state in which the drain processing of the accumulator back pressure of the release side frictional engagement element according to the differential pressure is prohibited, and the release side frictional engagement according to the differential pressure are performed. Switch to a state that allows drain processing of the accumulator back pressure of the joint element In a control device for an automatic transmission comprising a timing solenoid, when the occurrence of idling is detected during a shift, the shift solenoid is returned to the state before the start of the shift, and the timing valve While the drain process is prohibited and the accumulator back pressure of the disengagement side frictional engagement element is increased stepwise, the shift solenoid is returned to the state corresponding to the shift request when the idling is reversed to converge. In addition, the timing solenoid is allowed to drain the timing valve, and the accumulator back pressure of the disengagement side frictional engagement element is reduced stepwise.
[0011]
According to this configuration, when idling occurs during gear shifting, the hydraulic pressure of the release side frictional engagement element is increased to increase the torque capacity of the release side frictional engagement element. Since the hydraulic pressure is switched to the drain side by the solenoid, the hydraulic pressure cannot be increased as it is. Therefore, after returning the shift solenoid to the state where the hydraulic pressure before the start of shifting is supplied and ensuring that the accumulator back pressure can be controlled by prohibiting the drain processing in the timing valve, Increase accumulator back pressure step by step. And At the point when the sky blows to the convergence trend, Return the accumulator back pressure of the shift solenoid, timing solenoid and release side frictional engagement element to normal.
[0012]
Claim 2 In the described invention, the increase correction amount of the accumulator back pressure is determined according to at least one of the engine speed and the temperature of the hydraulic oil. According to such a configuration, the correction amount when increasing the accumulator back pressure of the disengagement side frictional engagement element is adjusted to the engine rotational speed and / or the viscosity of the hydraulic oil that correlates with the discharge amount of the oil pump driven by the engine. It is determined according to the correlated oil temperature.
[0013]
Claim 3 In the described invention, the accumulator back pressure of the engagement side frictional engagement element is controlled to the maximum hydraulic pressure only for a predetermined period from the start of the shift, and the predetermined period is set according to at least one of the engine speed and the temperature of the hydraulic oil. The configuration is determined as follows. According to such a configuration, the precharging control for controlling the accumulator back pressure of the engagement side frictional engagement element to the maximum hydraulic pressure is performed for a predetermined period from the start of the shift to fill the engagement side frictional engagement element with oil, and the precharge The control period is determined according to the engine rotation speed correlated with the discharge amount of the oil pump driven by the engine and / or the oil temperature correlated with the viscosity of the hydraulic oil.
[0014]
Claim 4 In the described invention, occurrence of idling is detected according to a deviation between the input shaft rotation speed of the transmission mechanism and the reference input shaft rotation speed calculated from the output shaft rotation speed of the transmission mechanism and the gear ratio before the shift. The configuration. According to this configuration, the input shaft rotation speed when the gear ratio of the transmission mechanism maintains the gear ratio before the shift is calculated from the output shaft rotation speed and the gear ratio before the shift, and this is calculated as the reference input shaft rotation speed (reference The deviation from the actual input shaft rotation speed (turbine rotation speed) is obtained as the turbine rotation speed), and when the actual input shaft rotation speed exceeds the reference input shaft rotation speed by a predetermined value or more, the occurrence of air blow is detected. To do.
[0015]
Claim 5 In the described invention, Reversal of air blow to convergence Is detected based on the differential value of the deviation between the input shaft rotational speed of the transmission mechanism and the output shaft rotational speed of the transmission mechanism and the reference input shaft rotational speed calculated from the gear ratio before the shift. According to this configuration, whether the actual input shaft rotational speed is moving away from the reference input shaft rotational speed, which is the input shaft rotational speed when the gear ratio of the speed change mechanism maintains the gear ratio before the shift, or the reference input shaft rotational speed. To determine whether the actual input shaft rotational speed is approaching, based on the differential value of the deviation between the actual input shaft rotational speed and the reference input shaft rotational speed, Reversal of air blow to convergence Is detected.
[0016]
Claim 6 In the described invention, the occurrence of air blow and Inversion to convergence Is detected on the basis of a comparison between a gear ratio calculated from the input shaft rotational speed and the output shaft rotational speed of the speed change mechanism and a predetermined value. According to this configuration, the gear ratio is calculated from the input shaft rotation speed and the output shaft rotation speed of the speed change mechanism, and the input shaft rotation speed increases with respect to the output shaft rotation speed to increase the gear ratio (gear ratio = input shaft rotation speed / The occurrence of idling is detected when the output shaft rotation speed increases above a predetermined value, and the convergence of idling occurs when the gear ratio becomes smaller than the predetermined value due to a decrease in input shaft rotation speed. Inversion to trend Is detected.
[0017]
【The invention's effect】
According to the invention of claim 1, When idling occurs, the torque capacity of the disengagement side frictional engagement element can be increased in a responsive and reliable manner to suppress idling while converging Inversion to trend Accordingly, the normal release control state is restored, so that it is possible to avoid excessively correcting the torque capacity of the disengagement side frictional engagement element, and it is possible to stably evacuate without increasing the cost or extending the shift time. There is an effect that the occurrence of blowing can be suppressed.
[0018]
Claim 2 According to the described invention, increase control of the accumulator back pressure is optimally controlled in accordance with changes in the discharge amount of the oil pump and the viscosity of the hydraulic oil, and the torque capacity of the disengagement side frictional engagement element is increased without excess or deficiency. There is an effect that can be. Claim 3 According to the described invention, by precharging the engagement side frictional engagement element with oil, the responsiveness of the hydraulic pressure in the engagement side frictional engagement element can be ensured, and hence the occurrence of idling is more effectively suppressed. There is an effect that can be done.
[0019]
Claim 4 According to the described invention, there is an effect that it is possible to detect the occurrence of idling with high accuracy and good response even when the vehicle speed changes. Claim 5 According to the described invention, the convergence of air blows Inversion to trend Can be detected with good response and accuracy as the time when the input shaft rotation speed is switched to the tendency to approach the rotation speed before the shift.
[0020]
Claim 6 According to the described invention, the occurrence and convergence of air blows Inversion to trend Can be easily detected regardless of changes in the vehicle speed.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 shows a drive system of a vehicle in an embodiment. An automatic transmission 103 is connected to an output shaft of an engine 101 via a torque converter 102, and is illustrated by the output shaft of the automatic transmission 103. The drive wheels of the vehicle that do not rotate are driven to rotate.
[0022]
The automatic transmission 103 includes a transmission mechanism unit 103A and a control valve unit 103B, and the control valve unit 103B is controlled by an A / T controller 104.
The A / T controller 104 has a built-in microcomputer, and detection signals from the A / T oil temperature sensor 105, the accelerator opening sensor 106, the vehicle speed sensor 107, the turbine rotation sensor 108, the engine rotation sensor 109, the air flow meter 110, and the like. A control signal is output to the control valve unit 103B by arithmetic processing.
[0023]
FIG. 2 is a skeleton showing the speed change mechanism 103A.
The transmission mechanism 103A includes two sets of planetary gears G1, G2, three sets of multi-plate clutches (high clutch H / C, reverse clutch R / C, low clutch L / C), and one set of brake bands 2 & 4 / B. It consists of one set of multi-plate brakes (low & reverse brake L & R / B) and one set of one-way clutch L / OWC.
[0024]
The two sets of planetary gears G1 and G2 are simple planetary gears composed of sun gears S1 and S2, ring gears r1 and r2, and carriers c1 and c2, respectively.
The sun gear S1 of the planetary gear set G1 is configured to be connectable to the input shaft IN by a reverse clutch R / C, and is configured to be fixed by a brake band 2 & 4 / B.
[0025]
The sun gear S2 of the planetary gear set G2 is directly connected to the input shaft IN.
The carrier c1 of the planetary gear set G1 is configured to be connectable to the input shaft IN by a high clutch H / C, while the ring gear r2 of the planetary gear set G2 is a carrier of the planetary gear set G1 by a low clutch L / C. The carrier c1 of the planetary gear set G1 can be fixed by a low & reverse brake L & R / B.
[0026]
A ring gear r1 of the planetary gear set G1 and a carrier c2 of the planetary gear set G2 are directly and integrally connected to the output shaft OUT.
In the transmission mechanism 103A having the above-described configuration, forward 1st to 4th speeds and reverse are realized by a combination of engagement states of the respective clutches and brakes as shown in FIG.
[0027]
In FIG. 3, the circle indicates the engaged state, and the part not marked with the symbol indicates that it is in the released state. In particular, the engaged state indicated by the black circle of the low & reverse brake L & R / B in the first speed is It shall indicate fastening in only one range. As shown in the combination of the engagement states of the clutches and brakes shown in FIG. 3, for example, when the upshift from the second speed to the third speed is performed, the brake band 2 & 4 / B is maintained while maintaining the engagement state of the low clutch L / C. The At the same time as releasing, the high clutch H / C is engaged. As described above, a shift in which the friction engagement element is switched by simultaneously controlling the engagement and release of the clutch / brake (friction engagement element) is referred to as a switching shift.
[0028]
FIG. 4 shows details of the control valve portion 103B.
The control valve 103B shown in FIG. 4 includes a shift valve (A) 1, a shift valve (B) 2, an L / C & H / C accumulator control valve 3, a 2 & 4 / B accumulator control valve 4, and an L / C timing valve (A) 5, L / C timing valve (B) 6, 2 & 4 / B timing valve (A) 7, 2 & 4 / B timing valve (B) 8, L / C accumulator 9, A 2 & 4 / B accumulator unit 10 and an H / C accumulator unit 11 are provided.
[0029]
The shift valve (A) 1 and the shift valve (B) 2 are set to shift speeds of 1st to 4th (OD) according to ON / OFF of the shift solenoid (A) 21 and the shift solenoid (B) 22. The oil passage is switched according to the corresponding combination of fastening and releasing.
Specifically, as shown in FIG. 5, the combination of ON / OFF of the shift solenoid (A) 21 and the shift solenoid (B) 22 is determined in advance for each shift stage. At the time of upshifting to high speed, the shift solenoid (A) 21 is continuously turned OFF, while the shift solenoid (B) 22 is switched from ON to OFF.
[0030]
When the shift solenoid (A) 21 and the shift solenoid (B) 22 are in the OFF state, the lower side of the pair of oil passages branched from one oil passage in the shift valve (A) 1 and the shift valve (B) 2 is selected. Conversely, when the shift solenoid (A) 21 and the shift solenoid (B) 22 are in the ON state, the upper side of the pair of oil passages is selected.
[0031]
Therefore, when upshifting from the second speed to the third speed, the hydraulic pressure supply path to the brake bands 2 & 4 / B is connected to the drain side (indicated by x in FIG. 4), while the low clutch L / C and the high clutch The D range pressure PD supply side is connected to the hydraulic pressure supply path of the clutch H / C.
The L / C & H / C accumulator control valve 3 reduces the line pressure PL according to the magnitude of the solenoid pressure PSOLA generated by the PL duty solenoid 23, and the back of the L / C accumulator 9 and the H / C accumulator unit 11. The accumulator pressure PACCMA that regulates the pressure is output.
[0032]
The solenoid pressure PSOLA produced by the PL duty solenoid 23 is also applied to a pressure modifier valve (P.MF.V) that regulates a modifier pressure that is a signal pressure of the line pressure PL produced by a pressure regulator valve (not shown). Led.
The 2 & 4 / B accumulator control valve 4 reduces the line pressure PL according to the magnitude of the solenoid pressure PSOLB generated by the 2 & 4 / B duty solenoid 24, and adjusts the back pressure of the 2 & 4 / B accumulator unit 10. Pressure PACCMB is output.
[0033]
The L / C timing valve (A) 5 has the signal pressure oil passage in the L / C timing valve (B) 6 at the drain side when the L / C timing solenoid 25 is OFF, and the signal pressure oil passage when the L / C timing solenoid 25 is ON. This is a switching valve for the communication side.
The L / C timing valve (B) 6 is controlled by the L / C accumulator 9 at the time of shifting up to the fourth speed or shifting down from the fourth speed, that is, at the time of shifting for releasing or engaging the low clutch L / C. Back pressure control is performed.
[0034]
The 2 & 4 / B timing valve (A) 7 has the signal pressure oil path in the 2 & 4 / B timing valve (B) 8 as the drain side when the 2 & 4 / B timing solenoid 26 is OFF, and the signal pressure oil path when the 2 & 4 / B timing solenoid 26 is ON. This is a switching valve for the communication side.
The 2 & 4 / B timing valve (B) 8 is connected to the 2 & 4 / B accumulator 10 when shifting up to the third speed or when shifting down from the third speed, that is, when shifting the brake band 2 & 4 / B. Back pressure control is performed.
[0035]
The L / C accumulator 9 is guided to the back pressure chamber through the L / C timing valve (B) 6 through the L / C timing valve (B) 6 to smoothly engage and release the low clutch L / C.
The 2 & 4 / B accumulator unit 10 is supplied with an accumulator control pressure PACCMB through a 2 & 4 / B timing valve (B) 8 to the back pressure chamber, so that the brake band 2 & 4 / B is smoothly engaged and released.
[0036]
The 2 & 4 / B accumulator unit 10 includes two accumulators that incorporate a piston and a spring in a cylinder and set the directions of the springs opposite to each other with respect to the back pressure to obtain two-stage accumulator characteristics with different shelf pressure levels. 10A and 10B.
In the H / C accumulator unit 11, the accumulator control pressure PACCMA is directly introduced into the back pressure chamber, so that the high clutch H / C is smoothly engaged and released.
[0037]
This H / C accumulator unit 11 also includes two accumulators 11A, in which a piston and a spring are incorporated in the cylinder and the directions of the springs are set opposite to each other with respect to the back pressure to obtain two-stage accumulator characteristics with different shelf pressure levels. 11B.
Here, in the shift control for automatically shifting from the first speed to the fourth speed in the D range, a shift command is issued according to a preset shift schedule based on the throttle opening and the vehicle speed, and the shift is performed to a shift stage based on the shift command. Accordingly, the A / T control unit 20 issues an ON / OFF command to the shift solenoid (A) 21 and the shift solenoid (B) 22 in accordance with the shift solenoid ON / OFF command for each gear position shown in FIG. It is controlled by that.
[0038]
In the following, the operation at the time of shifting will be described by taking the case of upshifting from 2nd speed to 3rd speed as an example. During upshifting from 2nd speed to 3rd speed, shift solenoid (A) 1 is continuously turned off while shifting. By switching the solenoid (B) 22 from ON to OFF, the D-range pressure PD is continuously supplied to the low clutch L / C, while the hydraulic pressure supply path to the brake bands 2 & 4 / B is drained, The D-range pressure PD is supplied to the high clutch H / C that has been drained until then, and the friction engagement element at the third speed is achieved by releasing the brake band 2 & 4 / B and engaging the high clutch H / C. Is switched to the engaged / released state, and the upshift from the second speed to the third speed is performed.
[0039]
When the brake band 2 & 4 / B is released in accordance with the upshift from the 2nd speed to the 3rd speed, the timing for draining the back pressure of the 2 & 4 / B accumulator unit 10 by the 2 & 4 / B timing valves 7 and 8 is determined. To be controlled.
As shown in the time chart of FIG. 6, at the time of upshifting from the 2nd speed to the 3rd speed, the shift solenoid (A) 1 is continuously turned OFF, while the shift solenoid (B) 22 is switched from ON to OFF. In addition, the 2 & 4 / B timing solenoid 26 is switched from the OFF state to the ON state.
[0040]
When the 2 & 4 / B timing solenoid 26 is OFF, the signal pressure applied to the 2 & 4 / B timing valve (B) 8 is drained to urge the 2 & 4 / B timing valve (B) 8 in the left direction in FIG. The accumulator control pressure PACCMB is directly introduced into the back pressure chamber of the 2 & 4 / B accumulator unit 10 by the spring, and the drain process by the 2 & 4 / B timing valve (B) 8 is prohibited.
[0041]
On the other hand, when the 2 & 4 / B timing solenoid 26 is turned ON, the 2 & 4 / B timing valve (A) 7 switches the signal pressure oil passage from the drain side to the communication side and acts in the direction of draining the 2 & 4 / B accumulator back pressure. The high clutch pressure PHC on the engagement side is supplied as the signal pressure to perform, so that the drain process by the pressure balance can be performed.
[0042]
On the other hand, the 2 & 4 / B timing valve (B) 8 is supplied with the fastening-side accumulator control pressure PACCMA as a signal pressure acting in the direction of supplying the 2 & 4 / B accumulator back pressure.
Thereby, the timing when the differential pressure ΔP between the accumulator control pressure PACCMA, which is the back pressure on the engagement side, and the high clutch pressure PHC, which is the operation pressure on the engagement side, becomes the set differential pressure (set by the spring load and the spool pressure receiving area). Thus, the spool of the 2 & 4 / B timing valve (B) 8 is switched to the side for draining the 2 & 4 / B accumulator back pressure.
[0043]
When the spool of the 2 & 4 / B timing valve (B) 8 is switched to the side of draining the 2 & 4 / B accumulator back pressure, the D range pressure PD is supplied as a signal pressure acting in the direction of draining the 2 & 4 / B accumulator back pressure. Accordingly, the drain state of the 2 & 4 / B accumulator back pressure is maintained.
The high clutch H / C on the engagement side increases the operating pressure after the end of the stroke of the clutch piston, and shows the first shelf pressure characteristic due to the piston stroke operation of the accumulator 11B as the operating pressure increases. Further, the accumulator 11A When the transition to the second shelf pressure characteristic by the piston stroke operation is completed and the stroke operation by the accumulator 11A is completed, the engagement pressure rises to the line pressure level at once, and the high clutch H / C is engaged.
[0044]
On the other hand, the brake band 2 & 4 / B on the disengagement side is rapidly reduced from the engagement pressure due to the line pressure level to the accumulator back pressure level, and the high clutch pressure PHC, which is the engagement side operation pressure, becomes 2 & 4 / B timing valve (B) 8 The 2 & 4 / B accumulator back pressure is drained to reduce the brake band pressure P24B with a large gradient, and the release band is released to release the brake band 2 & 4 / B.
[0045]
During the release control described above, the solenoid pressure PSOLB created by the 2 & 4 / B duty solenoid 24 is reduced from the maximum line pressure PL to the target solenoid pressure PSOLB corresponding to the input shaft torque at that time, and then shifted. The solenoid (B) 22 is switched from ON to OFF so that the fastening pressure of the brake band 2 & 4 / B is lowered to the accumulator back pressure level corresponding to the input shaft torque.
[0046]
Even when the low clutch L / C is released and the brake band 2 & 4 / B is engaged and the upshift from the 3rd speed to the 4th speed is performed, the L / C timing valve (B) 6 similarly uses the low clutch accumulator. Back pressure drain timing control is performed.
As described above, by controlling the drain timing of the accumulator back pressure of the disengagement side frictional engagement element, it is possible to optimally control the drain timing regardless of the variation of the frictional engagement element and the hydraulic pressure fluctuation. Especially during the first shift after the vehicle has been left for a long time, the oil in the clutch pack is completely drained and the normal hydraulic response cannot be obtained. There is.
[0047]
Therefore, in the present invention, the above-mentioned air blow is suppressed by the control as shown in the flowchart of FIG. 7, and the air blow suppression control will be described below with reference to the time chart of FIG.
The flowchart of FIG. 7 is executed when an upshift request from the second speed to the third speed is requested. In step S1, a shift solenoid is used to release the brake band 2 & 4 / B and to engage the high clutch H / C. (B) 22 is switched from ON to OFF, and 2 & 4 / B timing solenoid 26 is turned ON.
[0048]
In step S2, it is determined whether or not an idling has occurred during the upshift from the second speed to the third speed by the above control.
The occurrence of the idling is determined based on a detection signal (output shaft rotation speed) of the vehicle speed sensor 107 that extracts a rotation signal from the output shaft of the automatic transmission and a gear ratio in the second speed before the shift, based on the reference turbine rotation speed NtS ( When the actual turbine rotation speed Nt (input shaft rotation speed) detected by the turbine rotation sensor 108 is higher than the reference turbine rotation speed NtS + predetermined value HYS (1). (Nt> NtS + HYS (1)), the occurrence of air blow is detected.
[0049]
Further, the gear ratio (gear ratio = input shaft rotational speed / output shaft rotational speed) is determined from the detection signal (output shaft rotational speed) of the vehicle speed sensor 107 and the turbine rotational speed Nt (input shaft rotational speed) detected by the turbine rotational sensor 108. ) And the occurrence of idling may be detected when the gear ratio becomes larger than a reference gear ratio (1) set based on the gear ratio in the second speed before the gear change. .
[0050]
When the occurrence of idling is detected in step S2, the process proceeds to step S3, and the 2 & 4 / B timing solenoid 26 on the release side is turned off by turning off the 2 & 4 / B timing solenoid 26, so that the 2 & 4 / B timing valve (B ) It is prevented from being drained by the action of 8.
In step S4, the control duty of the 2 & 4 / B duty solenoid 24 is corrected to increase the 2 & 4 / B accumulator back pressure. Specifically, the base duty corresponding to the input shaft torque is corrected by a predetermined correction amount, and the correction amount is set according to the engine speed and the oil temperature as shown in FIG. The correction amount is increased as the engine speed is lower and the oil temperature is lower.
[0051]
In this embodiment, the oil pump that supplies hydraulic oil is driven by the engine, and the lower the engine speed, the smaller the oil pump discharge rate. Therefore, the lower the engine speed, the larger the correction amount and the release. The torque capacity on the side increases rapidly.
Further, since the hydraulic pressure response is delayed when the temperature of the hydraulic oil is low, the correction amount is increased as the oil temperature is lower, and the torque capacity on the disengagement side is increased rapidly.
[0052]
In step S5, according to the upshift request from the 2nd speed to the 3rd speed in order to return to the state in which the D range pressure PD is supplied from the state where the hydraulic pressure supply path of the brake band 2 & 4 / B is drained, that is, the state in the 2nd speed. The shift solenoid (B) 22 that has been turned off is switched on.
Release by increasing the 2 & 4 / B accumulator back pressure and switching the shift solenoid (B) 22 to ON so that the D range pressure PD is supplied to the brake band 2 & 4 / B as described above. The engagement pressure (torque capacity) of the brake band 2 & 4 / B on the side is increased, thereby eliminating the idling state due to insufficient torque capacity.
[0053]
Note that the amount of oil discharged from the clutch pack of the brake band 2 & 4 / B can be limited to some extent just by increasing the back pressure of the 2 & 4 / B accumulator, but the shift is not sufficient for early convergence of idling. The solenoid (B) 22 is switched to ON so that the D range pressure PD is supplied to the clutch pack of the brake band 2 & 4 / B.
[0054]
In step S6, it is determined whether or not the air blow has converged.
The convergence of the air blow occurs when the differential value of the deviation between the turbine rotational speed Nt and the reference turbine rotational speed NtS becomes smaller than a predetermined value HYS (2) (for example, 0) (d / dt (Nt−NtS ) <HYS (2)), it can be configured to detect the convergence of the air blow. According to this, when the tendency of the turbine rotation speed Nt to move away from the reference turbine rotation speed NtS changes to the tendency of returning toward the reference turbine rotation speed NtS, it can be detected as the convergence of the air blow.
[0055]
Further, a gear ratio (gear ratio = input shaft rotational speed / output shaft rotational speed) is calculated from the detection signal of the vehicle speed sensor 107 and the turbine rotational speed Nt detected by the turbine rotational sensor 108, and the gear ratio is calculated before shifting. When the gear ratio in the second speed is smaller than the reference gear ratio (2) set on the basis of the gear ratio, the convergence of the air blow may be detected.
[0056]
In addition, if it is the structure which detects the convergence of idling based on the differential value of the deviation of the turbine rotational speed Nt and the said reference turbine rotational speed NtS, it can detect the point in time when the idling is reversed to the convergence tendency with a good response. It is preferable to a configuration in which the air blow can be converged in a short time while avoiding a simple correction, and the convergence of the air blow is detected based on the gear ratio.
[0057]
When the convergence of the idling is detected in step S6, the processes of steps S7 to S9 are performed to return to the normal shift control state from the second speed to the third speed.
In step S7, the 2 & 4 / B timing solenoid 26 is turned ON so that the 2 & 4 / B accumulator back pressure on the release side is drained by the action of the 2 & 4 / B timing valve (B) 8.
[0058]
In step S8, the increase control of the 2 & 4 / B accumulator back pressure is stopped, and the 2 & 4 / B accumulator back pressure is returned to the base value.
In step S9, the shift solenoid (B) 22 is switched off to return to the third speed state in which the hydraulic pressure supply path of the brake bands 2 & 4 / B is drained.
When the occurrence of idling is detected as described above, if the 2 & 4 / B accumulator back pressure is increased by returning the shift solenoid to the original 2nd speed control state, the engagement pressure of the brake band 2 & 4 / B (Torque capacity) can be increased with good response, and the air blow can be converged in a short time. In addition, the 2 & 4 / B accumulator back pressure increase correction amount is set according to the engine rotation speed correlated with the oil pump discharge amount and the oil temperature indicating the viscosity of the hydraulic oil, so that the brake can be applied without overshooting. The fastening pressure (torque capacity) of the bands 2 & 4 / B can be increased enough for convergence of idling.
[0059]
By the way, the occurrence of idling is presumed to be caused by a delay in the hydraulic response on the engagement side, so that the high clutch H / C on the engagement side is precharged by controlling the back pressure. The precharge control will be described with reference to the flowchart of FIG.
In the flowchart of FIG. 9, in step S11, it is determined whether or not the upshift from the second speed to the third speed is started, and when the upshift from the second speed to the third speed is started, the process proceeds to step S12.
[0060]
In step S12, the precharge time TIM1 is set according to the engine speed and the oil temperature. As shown in FIG. 10, the precharge time TIM1 is made longer as the engine speed is lower and the oil temperature is lower. This is because, like the setting characteristic of the correction amount, the oil pump discharge amount decreases as the engine speed decreases, and the hydraulic pressure response decreases as the hydraulic oil temperature decreases.
[0061]
In step S13, a timer that measures the elapsed time since the start of the upshift from the second speed to the third speed is counted up. In step S14, whether or not the time measured by the timer is shorter than the precharge time TIM1. Is determined.
When the time measured by the timer is shorter than the precharge time TIM1, the process proceeds to step S15, and precharge for the high clutch H / C on the engagement side is executed.
[0062]
The precharge is performed by increasing the H / C accumulator back pressure to the maximum pressure. Specifically, the ac control pressure PACCMA is set to the maximum line pressure by the control of the PL duty solenoid 23. Like that.
When the precharge with the H / C accumulator back pressure as the maximum pressure is continued for the precharge time TIM1, the process proceeds from step S14 to step S16, the precharge is stopped, and the H / C accumulator back pressure is applied to the input shaft. Return to the value corresponding to the torque.
[0063]
In the above-described embodiment, if an idling occurs during an upshift from the 2nd speed to the 3rd speed, the torque capacity is increased by the back pressure correction control only on the brake band 2 & 4 / B side that is the release side, and the convergence of the idling occurs. However, at the same time, the back pressure on the high clutch H / C side that is the engagement side may be corrected and controlled.
Specifically, in the interval in which the 2 & 4 / B accumulator back pressure is increased, the H / C accumulator back pressure may be increased by controlling the PL duty solenoid 23, and the increase correction amount of the H / C accumulator back pressure is also 2 & 4. Like the case of increasing the / B accumulator back pressure, the engine speed and the oil temperature may be set.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a vehicle drive system in an embodiment.
FIG. 2 is a skeleton diagram showing a speed change mechanism in the embodiment.
FIG. 3 is a diagram showing a combination of engagement states of frictional engagement elements at gear positions in the embodiment.
FIG. 4 is a hydraulic circuit diagram showing a control valve portion in the embodiment.
FIG. 5 is a diagram showing a combination of ON / OFF of shift solenoids A and B at each gear position in the embodiment.
FIG. 6 is a time chart showing control at the time of second-speed → third-speed upshift in the embodiment.
FIG. 7 is a flowchart showing control on the disengagement side at the time of second-speed → third-speed upshift in the embodiment.
FIG. 8 is a diagram showing a correction amount characteristic of a back pressure control amount in the embodiment.
FIG. 9 is a flowchart showing pre-charge control on the engagement side at the time of second speed → third speed upshift in the embodiment.
FIG. 10 is a diagram showing characteristics of precharge time in the precharge control.
[Explanation of symbols]
1. Shift solenoid (A)
2. Shift solenoid (B)
3. Accumulation control valve for L / C & H / C
4 ... Accum control valve for 2 & 4 / B
5 ... L / C timing valve (A)
6 ... L / C timing valve (B)
7… 2 & 4 / B Timing Valve (A)
8 ... 2 & 4 / B Timing Valve (B)
9 ... L / C accumulator
10 ... 2 & 4 / B accumulator unit
11 ... H / C accumulator unit
21 ... Shift solenoid (A)
22 ... Shift solenoid (B)
23 ... PL duty solenoid
24 ... 2 & 4 / B duty solenoid
25 ... L / C timing solenoid
26 ... 2 & 4 / B timing solenoid
101 ... Engine
102 ... Torque converter
103 ... Automatic transmission
103A: Transmission mechanism
103B ... Control valve part
104 ... A / T controller
105 ... A / T oil temperature sensor
106 ... accelerator opening sensor
107: Vehicle speed sensor
108: Turbine rotation sensor
109 ... Engine rotation sensor
G1, G2 ... Planetary gear
H / C ... High clutch
R / C ... Reverse clutch
L / C ... Low clutch
2 & 4 / B ... Brake band
L & R / B ... Low & Reverse Brake
L / OWC ... one-way clutch

Claims (6)

A control device for an automatic transmission configured to change speed by switching friction engagement elements that simultaneously perform fastening control and release control of two different friction engagement elements,
A shift solenoid that switches on / off the oil supply / discharge to each friction engagement element;
A duty solenoid for controlling the back pressure of the accumulator interposed in the oil supply path to each friction engagement element;
A timing valve that drains the accumulator back pressure of the disengagement side frictional engagement element in accordance with a differential pressure between the operating pressure of the engagement side frictional engagement element and the back pressure of the engagement side accumulator;
By switching the supply / drain of the signal pressure to the timing valve, a state in which the drain processing of the accumulator back pressure of the release side frictional engagement element according to the differential pressure is prohibited, and the release side frictional engagement according to the differential pressure are performed. A timing solenoid that switches to a state that permits draining of the accumulator back pressure of the combined element ;
In an automatic transmission control device comprising:
When the occurrence of idling is detected during a shift, the shift solenoid is returned to the state before the start of the shift, the drain process in the timing valve is prohibited by the timing solenoid, and the release side frictional engagement element While increasing the accumulator back pressure stepwise,
When the air blow reverses to the convergence tendency, the shift solenoid is returned to the state corresponding to the shift request, the draining process in the timing valve is permitted by the timing solenoid, and the release side frictional engagement element A control device for an automatic transmission characterized by stepwise reducing accumulator back pressure. 2. The control device for an automatic transmission according to claim 1, wherein an increase correction amount of the accumulator back pressure is determined according to at least one of an engine speed and a temperature of hydraulic oil. The accumulator back pressure of the engagement side frictional engagement element is controlled to the maximum hydraulic pressure only for a predetermined period from the start of the shift, and the predetermined period is determined according to at least one of the engine rotation speed and the hydraulic oil temperature. The control device for an automatic transmission according to claim 1 or 2, characterized in that: The occurrence of the idling is detected according to a deviation between the input shaft rotation speed of the transmission mechanism and the reference input shaft rotation speed calculated from the output shaft rotation speed of the transmission mechanism and the gear ratio before the shift. The control device for an automatic transmission according to any one of claims 1 to 3. The inversion of the idling to the convergence tendency is based on the differential value of the deviation between the input shaft rotation speed of the transmission mechanism and the reference input shaft rotation speed calculated from the output shaft rotation speed of the transmission mechanism and the gear ratio before the shift. The automatic transmission control device according to any one of claims 1 to 4, wherein the control device is detected. 2. The occurrence of the idling and the reversal to the convergence tendency are detected based on a comparison between a gear ratio calculated from an input shaft rotation speed and an output shaft rotation speed of the speed change mechanism and a predetermined value. The control apparatus of the automatic transmission as described in any one of -3.

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