JPH0556421B2 - - Google Patents

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to the movement (stroke) of a piston that operates a band brake that fixes rotating elements in an automatic transmission that automatically changes gears depending on the driving condition of a vehicle. ) The present invention relates to a control device that performs position storage control.

<Prior art> As an automatic transmission for vehicles, hydraulic pressure is supplied to frictional engagement elements such as clutches and brakes, and transmission ratio switching ( It is known that automatic gear shifting is performed according to the driving condition of the vehicle, and pressure oil is supplied to these frictional engagement elements in order to protect various devices and equipment and maintain a comfortable ride. Normally, the shift is performed gradually in accordance with certain predetermined characteristics from the initial oil pressure supplied after the transmission of the shift start signal.

The general structure of such a conventional automatic transmission for a vehicle is shown in FIG. 2, in which a crankshaft 12 of an engine 11 that serves as a power source for the vehicle is integrally connected to a pump 14 of a torque converter 13. The torque converter 13 includes a pump 14, a turbine 15, a stator 16, and a one-way clutch 17.
The stator 16 is connected to the case 18 via this one-way clutch 17, and the one-way clutch 17 allows the stator 16 to rotate in the same direction as the crankshaft 12, but does not allow rotation in the opposite direction. It is becoming. turbine 1
5 is transmitted by an input shaft 19 to a gear transmission disposed at the rear thereof that achieves four forward speeds and one reverse speed.

The gear transmission has three sets of clutches 20, 21,
22, two sets of brakes 23 and 24, one set of one-way clutch 25, and one set of Ravigneau type planetary gear mechanism 26. This Lavigneau type planetary gear mechanism 26 rotatably supports a ring gear 27, a long pinion gear 28, a short pinion gear 29, a front sun gear 30, a rear sun gear 31, and the pinion gears 28 and 29, and is rotatably fitted to the input shaft 19. The ring gear 27 is composed of a carrier 32 and a carrier 32.
3, the front sun gear 30 is connected to the input shaft 19 via the kickdown drum 34 and the front clutch 20, the rear sun gear 31 is connected to the input shaft 19 via the rear clutch 21,
The carrier 32 is connected to the case 18 via a low reverse brake 24 and a one-way clutch 25 that are arranged in parallel with each other, and also receives input via a 4-speed clutch 22 that is arranged at the rear end of this gear transmission. It is connected to the shaft 19. The kickdown drum 34 can be integrally connected to the case 18 by the kickdown brake 23, and the torque passing through the planetary gear mechanism 26 is transmitted from an output gear 35 (not shown) fixed to the output shaft 33. It is transmitted to the drive shaft side of the drive wheels.

Each of the above-mentioned clutches 20 to 22 which are frictional engagement elements
The brakes 23 and 24 are each composed of hydraulic equipment equipped with an engaging piston device or a servo device, and are hydraulically controlled by pressure oil generated by an oil pump (not shown) connected to the pump 14 of the torque converter 13. Although it is operated through a device, its detailed structure and operation are disclosed in Japanese Patent Application Laid-open No. 58-46258.
This is as disclosed in the publication.

First, shifting from first speed to second speed will be explained based on the hydraulic circuit shown in FIG. 3.

For example, in the 1st gear range other than the 1st gear fixed range, the front clutch 20 and 4th gear clutch 22 are in a disconnected state, the kickdown brake 23 and the low reverse brake 24 are released, and the rear clutch 21 is connected, and the one-way clutch 25 is in a functioning state. In this case, upshifting to second gear is achieved only by engaging the kick-down brake 23, and the one-way clutch 25 is rendered inoperative.

A 1-2 shift valve 37 is connected to an engagement side hydraulic chamber 36a of a kick-down servo 36 that controls the operation of the kick-down brake 23 via an oil passage 38. control valve 3
9 and shift control valve 40 are connected to oil passages 41 and 4, respectively.
It is connected via 2. Kickdown drum 3
A band brake 23a is wound around the band brake 2, and the kickdown drum 34 is connected to the band brake 2.
3a, it is integrally fixed to the case side of the transmission.

The pair of solenoid valves 43 and 44 that control the operation of the shift control valve 40 in the first gear position both open the oil passages 45 and 46, so that the shift control valve 4
The spool 47 in the center of 0 is displaced to the left in FIG. 3 to shift the oil passage 42 to the oil drain port of the control valve
EX, and the spool 48 of the 1-2 shift valve 37 is in a state displaced to the left end in FIG. As a result, the oil passage 38 communicates with the oil drain port EX of the 1-2 shift valve 37, and the compression coil spring 4 provided in the withdrawal side hydraulic chamber 36b of the kickdown servo 36
The piston 50 is returned to the right side in FIG. 3 by the spring force 9, and the engagement of the kick-down brake 23 with the kick-down drum 34 is released. Further, of the two oil passages 51 and 52 connected to the speed change control valve 39, the duty rate of the solenoid valve 54 attached to one oil passage 51 and whose duty is controlled by the electronic control device 53 is set to 100%. Therefore, oil pressure is not acting on the oil passage 51. For this reason, the spool 55 of the speed change control valve 39 is
Displaced to the left, the oil passage 41 communicates with the oil drain port EX of the speed change control valve 39.

When upshifting from this state to 2nd speed, the electronic control unit 53 operates one of the solenoid valves 43 to block the oil passage 45 based on the vehicle running conditions, so the central spool 47 is moved to the right side in FIG. Pressure oil from the oil pump (hereinafter referred to as line pressure) is supplied to the 1-2 shift valve 37 from an oil passage 56 connected to the shift control valve 40 through the oil passage 42. Ru. Therefore, the spool 48 of the 1-2 shift valve 37 is displaced to the right end in FIG. On the other hand, since the duty rate of the solenoid valve 54 is reduced by the electronic control device 53, the line pressure acts on the oil passages 51 and 52, and due to the difference in pressure receiving area of the spool 55 of the speed change control valve 39, the spool 55 moves as shown in FIG. It is displaced to the right, and the oil passages 41 and 52 communicate with each other via the speed change control valve 39. As a result, the line pressure from the oil passage 52 is supplied to the engagement side hydraulic chamber 36a of the kickdown servo 36 through the oil passages 41 and 38.
The piston 50 is displaced to the left in FIG. 3 to operate the kickdown brake 23, and the kickdown drum 34 is tightened and fixed by the band brake 23a.

Next, the shift from third speed to second speed will be explained based on FIG. 3.

A downshift from third gear to second gear is accomplished by releasing the front clutch 20 and engaging the kickdown brake 23. Although the front clutch 20 is not shown in the figure, it is engaged by hydraulic pressure and returns by a spring when the hydraulic pressure is released. and the drum 34, so that the two can be engaged and disengaged. Hydraulic chamber 3 on the engagement side of the front clutch 20 and on the disengagement side of the kickdown servo 36
6b is connected by an oil passage 60, and a 2-3 speed shift valve 61 is connected to the oil passage 60 by an oil passage 62. The 2nd-3rd speed shift valve 61 is connected to the oil passage 38 by an oil passage 63, and is connected to oil passages 62 and 6 by hydraulic pressure from a shift control valve (not shown).
3 is controlled to be communicated or disconnected. 64 is an oil drain path, and 65 is an orifice provided in the oil drain path 64.

Looking at the process of shifting from 3rd speed to 2nd speed with the above structure, in the 3rd speed state, the oil pressure controlled by the shift control valve 39 passes through the 1st-2nd speed shift valve 37 and is applied to the kick-down servo 36. It enters the coupling side hydraulic chamber 36a, and also passes through the 2nd-3rd speed shift valve 61 from the oil passage 63 to the disengagement side hydraulic chamber 36 of the kickdown servo 36.
b, supplied to the engagement side of the front clutch 20; When a shift signal to the second speed is issued, in the second-to-third speed shift valve 61, the oil passages 62 and 63 are shut off, and the oil passage 62 and the oil drain passage 64 are communicated with each other. Therefore, the release side hydraulic chamber 36 of the kickdown servo 36
b and the hydraulic pressure of the front clutch 20 are discharged,
The piston 50 is displaced to the left in FIG. 3 to operate the kick-down brake 23, the kick-down drum 34 is tightened and fixed by the brake band 23a, and the front clutch 20 is disengaged to achieve second gear.

As mentioned above, when shifting from 1st to 2nd gear, 3
In either case, when shifting from 1st to 2nd speed, the kickdown drum 34 is fixed by displacing the piston 50, activating the kickdown brake 23, and tightening the band brake 23a. Further, although a detailed explanation is omitted, the kickdown drum 34 is fixed by the band brake 23a even when shifting to the fourth speed.

When fixing the kick-down drum 34, the kick-down drum 34 is fixed in synchronization with the disengagement of related clutches so that large torque fluctuations do not occur. That is, as shown in Figure 3,
When shifting from 3rd speed to 2nd speed, the piston sensor 66 detects the stroke completion position of the piston 50, and the detected position is detected by the kickdown servo 36.
The supply pressure to the piston 50 is expressed as a partial pressure ratio k that determines the starting position of reducing the hydraulic pressure to the engagement side hydraulic chamber 36a, and is expressed as k ₂ , and the supply pressure to the piston 50 is set so that the rotation stop timing of the kick-down drum 34 and the stroke completion timing of the piston 50 coincide. is controlled by feedback using the following formula.

Duty rate corrected with one feedback = α [(dNd/dt)/Nd-{d(k-k ₂ )/dk}/k
−k ₂ ]o/o…(1) Note that α is a constant.

In the above equation, k ₂ is the piston sensor 66 at the stroke completion position of the piston 50 in the 2nd and 4th speeds, which stops the rotation of the kick-down drum 34.
The output value of
Feedback control is performed by replacing the values with the latest values at the end of each shift (speed → 2nd gear, 3rd gear → 2nd gear, 3rd gear → 4th gear).

<Problems to be Solved by the Invention> However, even in the same tightened state of the kick-down drum 34, the direction of the torque applied to the kick-down drum 34 is reversed during acceleration and during engine braking, so that the pressing of the band brake 23a is The torque will also be different. (Pushing torque of the band brake 23a is applied in the self-locking direction during 2nd speed engine braking and 4th speed engine braking, and in the anti-self-locking direction during 2nd speed engine braking and 4th speed acceleration.)
If the pressing torque of the band brake 23a is different, the stroke completion position of the piston 50 will be different k ₂
If the value of _k2 fluctuates and the value of k2 is not accurate, the correction duty rate in equation (1) described above will become inaccurate, and the kick-down drum 34 will be It becomes impossible to match the rotation stop timing and the stroke completion timing of the piston 50.

In addition, from 1st to 2nd speed, which is controlled using k ₂ ,
Even when shifting from 3rd to 4th speed, the pushing torque of the band brake 23a is applied in the anti-self-locking direction k ₂
When the value of is less than the normal value, as shown by the broken line in FIG. 5, the period between when a shift command is issued and when the shift starts, the command oil pressure is lowered and the moving speed of the piston 50 is reduced becomes longer from Δt to Δta. Therefore, the time to start shifting is also delayed by that amount.

The present invention has been made in view of the above-mentioned circumstances, and is an automatic transmission control capable of matching the rotational element stop timing and the piston movement completion timing without delaying the shift start timing regardless of the direction of the torque applied to the rotational element. The purpose is to provide equipment.

<Means for Solving the Problems> To achieve the above object, the automatic transmission control device of the present invention includes a rotating element 34 and a band brake 23a capable of fixing the rotating element.
and a servo device 3 that engages and operates the band brake.
6, hydraulic control devices 53, 54, 55 that supply hydraulic pressure for operating the servo device, and position detection means 66 for detecting the position of the piston 50 moving within the servo device, the rotating element The hydraulic control device is configured to control the hydraulic pressure supplied to the servo device according to the piston position K1 detected by the position detecting means and the stored piston movement completion position K2 during a shift in which the piston is fixed. In the automatic transmission, the piston position detected by the position detection means when the magnitude and direction of the torque applied to the band brake satisfy predetermined conditions when the rotating element is fixed is defined as the piston movement completion position. The feature is that a storage means is provided for storing the information as follows.

<Operation> The servo device is operated using the piston movement completion position stored by the storage means as the piston stroke completion position at the time of gear change, and the rotation stop timing of the rotating element and the piston stroke completion timing are made to coincide.

<Embodiment> An embodiment of the control device for an automatic transmission according to the present invention is shown in FIG. 1, which is a flowchart of a storage means, and FIGS. 3 and 4, which show the hydraulic circuit of the transmission described above.
This will be explained with reference to FIG.

The stroke completion position of the piston 50 is determined by the partial pressure ratio k
When expressed as k ₂ , the value of k ₂ is larger when torque is applied to the kick-down drum 34 as a rotating element in the self-locking direction than when it is applied in the anti-self-locking direction, and the value of k 2 is also the same. Even when torque is applied in the self-locking direction, the kick-down drum 3 is stronger during acceleration in 2nd gear than during engine braking in 4th gear.
Since the torque applied to 4 is large, the value of k ₂ is also large. From the above, in this embodiment, when the magnitude and direction of the torque applied to the band brake 23a satisfy predetermined conditions when the kick-down drum 34, which is a rotating element, is in a fixed state, the transition from 1st to 2nd gear is determined. This is the point in time when 0.1 second has elapsed after the gear shift, and the value of k ₂ at this time is used as the reference value for the stroke completion position of the piston 50. In addition, the kickdown drum 34
When the magnitude and direction of the torque applied to the band brake 23a satisfy predetermined conditions in the fixed state, the torque is not necessarily 0.1 after shifting from 1st to 2nd gear.
It is not limited to the point in time when seconds have elapsed. The magnitude and direction of the torque applied to the kick-down drum 34 are determined from the throttle opening _θt .

Next, the piston 50 using the storage means of this embodiment
The stroke positioning control (method for determining _k2 ) will be explained in detail.

After connecting the battery, reset the _k2 flag and determine whether the ignition switch is on. When the ignition switch is ON, it is determined whether or not the _k2 flag is set, and if the _k2 flag is not set, that is, the engine changes from 1st gear to 2nd gear for the first time after connecting the battery. In case of shifting, set the timer to 5 seconds. When a time-up of 5 seconds is determined, the partial pressure ratio k ₁ at the stroke start position of the piston 50 is detected, and after the battery is connected, the partial pressure ratio k ₂ for the first shift from 1st to 2nd speed is k ₁ +35.86 (%) and calculated
The value of _k2 is stored and a flag is set for this value of _k2 . Next, it is determined whether a shift command has been issued, and if a shift command has been issued, it is determined whether the shift command is for shifting from 1st speed to 2nd speed. 1st to 2nd gear
If it is determined that the gear is to be shifted to a higher speed, the throttle opening θt is detected, and it is determined whether or not the throttle opening θt is 50% or more. When the throttle opening θt is determined to be 50% or more, it is determined whether the shift from 1st to 2nd gear has been completed (whether the supply pressure to the kickdown servo 36 has reached the maximum), and the shift is completed. If it is determined that the process has ended, the timer is set to 0.1 seconds. When a time-up of 0.1 seconds is determined, the partial pressure ratio k ₂ ' at the position of the piston 50 at that time is detected, and this
The value of k ₂ ′ is replaced as k ₂ and the replaced value of k ₂ is stored. That is, when the kick-down drum 34 is in a fixed state, the band brake 23
When the magnitude and direction of the torque applied to a satisfy the predetermined conditions, after shifting from 1st gear to 2nd gear,
After 0.1 seconds have elapsed, the piston position detected by the piston sensor 66, which is a position detection means, is stored as the piston movement completion position.

The stroke completion position of the piston 50 is determined by using this stored _k2 value as the partial pressure ratio value of the stroke completion position of the piston 50 when shifting from 3rd gear to 2nd gear, 3rd gear to 4th gear, and 1st gear to 2nd gear. Control.
That is, the kickdown servo 36 as a servo device is operated in accordance with the piston movement completion position K2 to control the stroke completion position of the piston 50. Then, the value of the partial pressure ratio k ₂ at the stroke position of the piston 50 at every point (A point) when the throttle opening is 50% or more and 0.1 seconds have elapsed after shifting from 1st to 2nd speed is replaced as the latest value, and the stroke of the piston 50 is calculated. Control completion position.

Therefore, by storing the maximum value of k ₂ using the method described above and controlling the stroke completion position of the piston 50 based on this value of k ₂ , k ₂ can be adjusted depending on the direction of the torque applied to the kickdown drum 34. The value will no longer be below the normal value, and the piston 50
The section where the stroke speed is reduced does not become long. As a result, there is no delay in the shift start timing when shifting from 1st speed to 2nd speed and from 3rd speed to 4th speed. Furthermore, by using the value of k ₂ stored in the above-described manner when shifting from 3rd speed to 2nd speed, the value of k ₂ becomes constant regardless of the pressing torque of the band brake 23a, and the kick-down drum 34 This makes it possible to always match the rotation stop timing of the piston 50 with the stroke completion timing of the piston 50.

<Effects of the Invention> By controlling the piston stroke completion position using the automatic transmission control device of the present invention, the rotation element stop timing and piston movement completion timing can be adjusted without delaying the shift start timing regardless of the direction of torque applied to the rotation element. can be matched.

[Brief explanation of the drawing]

FIG. 1 is a flowchart according to an embodiment of the present invention, FIG. 2 is a conceptual diagram of a mechanism showing the structure of an automatic transmission, and FIG. 3 is a configuration of an example of a hydraulic system of a transmission that is controlled by the present invention. Figure 4 is an explanatory diagram of the piston sensor, and Figure 5 is a diagram showing the shift characteristics. In the figure, b shows the piston sensor output with respect to time, taking as an example a shift from 1st speed to 2nd speed, and c in the figure shows a change in output shaft torque with respect to time, taking a shift from 1st speed to 2nd speed as an example. In the drawing, 20 is a front clutch, 23 is a kickdown brake, 23a is a band brake, 3
4 is a kickdown drum, 36 is a kickdown servo, 37 is a 1st-2nd speed shift valve, 39 is a speed change control valve, 50 is a piston, 61 is a 2nd-3rd speed shift valve,
66 is a piston sensor.

Claims (1)

[Claims] 1. A rotating element 34 and a band brake 23a capable of fixing the rotating element.
and a servo device 3 that engages and operates the band brake.
6, hydraulic control devices 53, 54, 55 that supply hydraulic pressure for operating the servo device, and position detection means 66 for detecting the position of the piston 50 moving within the servo device, the rotating element The hydraulic control device is configured to control the hydraulic pressure supplied to the servo device according to the piston position K1 detected by the position detecting means and the stored piston movement completion position K2 during a shift in which the piston is fixed. In the automatic transmission, the piston position detected by the position detection means when the magnitude and direction of the torque applied to the band brake satisfy predetermined conditions when the rotating element is fixed is defined as the piston movement completion position. 1. A control device for an automatic transmission, characterized in that a storage means is provided for storing the information as follows.