JP3246761B2 - Control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission.

[0002]

2. Description of the Related Art A conventional control device for an automatic transmission is disclosed in Japanese Patent Application Laid-Open No. 2-80860. That is, a shift operation lever operated to select at least one of the forward travel range and the reverse travel range,
An automatic transmission that is automatically switched to a forward gear or a reverse gear in response to the operation position of the shift operation lever, and the vehicle speed detected by the vehicle speed sensor is determined in advance. This is a control device of a type in which switching to the reverse gear is prohibited when a predetermined value is exceeded.

[0003]

However, when the vehicle speed sensor fails, the above-described conventional automatic transmission control device holds the vehicle speed data immediately before the vehicle speed sensor fails. If the value is larger than a predetermined value, switching to the reverse gear is prohibited, so that there is a problem that the vehicle cannot reverse. An object of the present invention is to solve such a problem.

[0004]

SUMMARY OF THE INVENTION According to the present invention, when a failure of a vehicle speed sensor is detected, a failure immediately before the failure held by the vehicle speed sensor is detected .
The vehicle speed judgment means makes any judgment based on the vehicle speed data.
In order to solve the above-mentioned problem , the reverse is permitted. That is, a control device for an automatic transmission according to the present invention includes a vehicle speed sensor that detects a vehicle speed, a vehicle speed determination unit that determines whether the vehicle speed detected by the vehicle speed sensor is equal to or higher than a preset reverse prohibition speed, Reverse prohibiting means for prohibiting switching from the forward range to the reverse range or prohibiting the supply of oil pressure to the friction element required during reverse when the vehicle speed is determined to be equal to or higher than the reverse prohibiting speed, has a vehicle speed sensor failure detecting means for detecting that the vehicle speed sensor fails, the failure of the vehicle speed sensor by the vehicle speed sensor failure detecting means is detected, vehicle speed sensor failure straight
The previous vehicle speed data is retained, and the
If the vehicle speed judgment means is based on previous vehicle speed data,
The reverse is permitted by the reverse permission means regardless of the determination .

[0005]

When a failure of the vehicle speed sensor is detected, the vehicle speed sensor
Holds the vehicle speed immediately before the breakdown, and the vehicle speed
Vehicle speed based on the vehicle speed data just before
Judgment, but reverse permission regardless of this determined vehicle speed
Reverse is permitted by means . That is, even if the vehicle speed data held immediately before the failure of the vehicle speed sensor is equal to or higher than the reverse prohibition vehicle speed, in the case of the reverse range , the vehicle is shifted to the reverse gear.
Switching is performed. Also, erroneous detection of the vehicle speed sensor
Even if it is determined that the vehicle speed sensor is malfunctioning,
Gear shift based on the vehicle speed data immediately before the breakdown.
Therefore, sudden deceleration can be prevented.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Description will be made based on 0. FIG. 2 is a skeleton diagram showing the power transmission mechanism of the automatic transmission with four forward speeds and one reverse speed with overdrive. This power transmission mechanism includes a torque converter 10
, An input shaft 13 to which torque from an engine output shaft 12 is transmitted, an output shaft 14 to transmit driving force to a final drive, a first planetary gear set 15, and a second planetary gear set 1
6, reverse clutch 18, high clutch 20, forward clutch 22, overrunning clutch 24, low and reverse brake 26, band brake 28,
It has a low one-way clutch 29 and a forward one-way clutch 30. The torque converter 10 has a lock-up clutch 11 built therein. First
The planetary gear set 15 includes a sun gear S1, an internal gear R1, and a carrier PC1 that supports a pinion gear P1 that meshes with both gears S1 and R1. The planetary gear set 16 includes a sun gear S2, an internal gear And a carrier PC2 that supports a pinion gear P2 that meshes with both gears S2 and R2 at the same time. The carrier PC1 can be connected to the input shaft 13 via the high clutch 20, and the sun gear S1 is
The input shaft 13 can be connected via a reverse clutch 18. The carrier PC1 includes a forward clutch 22 and a forward one-way clutch 3 connected in series with the forward clutch 22.
0, or via an overrunning clutch 24 arranged in parallel with the forward clutch 22 and the forward one-way clutch 30. The sun gear S2 is always connected to the input shaft 13, and the internal gear R1 and the carrier PC2 are always connected to the output shaft 14. The low and reverse brake 26 is capable of fixing the carrier PC1, and the band brake 28 is a sun gear S1.
Can be fixed. The low one-way clutch 29 is arranged in such a direction that the forward rotation (rotation in the same direction as the engine output shaft 12) of the carrier PC1 is allowed but the reverse rotation (rotation in the opposite direction to the forward rotation) is not allowed.

The power transmission mechanism includes clutches 18, 2
0, 22 and 24, and brakes 26 and 28 in various combinations to operate planetary gear sets 15 and 1
6 (S1, S2, R1, R2, PC1, and P
The rotation state of C2) can be changed, whereby the rotation speed of the output shaft 14 with respect to the rotation speed of the input shaft 13 can be variously changed. By operating the clutches 18, 20, 22 and 24 and the brakes 26 and 28 in a combination as shown in FIG. 3, four forward speeds and one reverse speed can be obtained. In FIG. 3, the symbols .DELTA. Indicate operating clutches and brakes, and .alpha.1 and .alpha.2 are ratios of the number of teeth of the sun gears S1 and S2 to the number of teeth of the internal gears R1 and R2, respectively. 14 is a ratio of the rotation speed of the input shaft 13 to the rotation speed of the input shaft 14.

FIGS. 4, 5 and 6 show a hydraulic control device for controlling the operation of the power transmission mechanism. This hydraulic control device
Pressure regulator valve 40, pressure modifier valve 42, line pressure solenoid 44, modifier pressure accumulator 46, pilot valve 4
8, torque converter relief valve 50, lock-up control valve 52, first shuttle valve 54,
Lock-up solenoid 56, manual valve 58, first shift valve 60, second shift valve 62, first shift solenoid 64, second shift solenoid 66, servo charger valve 68, 3-2 timing valve 70,
4-2 relay valve 72, 4-2 sequence valve 7
4, first reducing valve 76, second shuttle valve 78, overrunning clutch control valve 80, overrunning clutch solenoid 8
2. Overrunning clutch reducing valve 8
4, a 1-2 accumulator 88, a 2-3 accumulator 88, a 3-4 accumulator 90, an ND accumulator 92, an accumulator control valve 94, a filter 96, etc., which are connected to each other as shown in the drawing. And the torque converter 10 described above.
(In this, an apply chamber 11a and a release chamber 11b of the lock-up clutch 11 are formed.), A forward clutch 22, a high clutch 20, and a band brake 28 (note that the apply chambers 28a, 28
A speed release chamber 28b and a fourth-speed apply chamber 28c are formed), the reverse clutch 18, the low-and-reverse brake 26, and the overrunning clutch 24 are also connected as shown, and the feedback accumulator 32 is Equipped with variable capacity vane type oil pump 34, oil cooler 36, front lubrication circuit 3
7 and the rear lubrication circuit 38 are also connected as shown. A detailed description of these valves will be omitted. The parts whose description is omitted are described in JP-A-63-251
It is the same as that described in No. 6521.

FIGS. 7, 8 and 9 show solenoids 44, 56,
A control unit 300 for controlling the operation of 64, 66 and 82 is shown. The control unit 300 includes an input interface 311, a reference pulse generator 312,
CPU (Central Processing Unit) 313, ROM (Read Only Memory) 314, RAM (Random Access Memory) 3
15 and an output interface 316, which are connected by an address bus 319 and a data bus 320. The control unit 300 includes an engine speed sensor 301, a vehicle speed sensor 30
2. Throttle opening sensor 303, select position switch 304, kick down switch 305, idle switch 306, full throttle switch 307, oil temperature sensor 308, input shaft rotation speed sensor 309, overdrive switch 310, travel distance sensor 399, etc. Is input. On the other hand, shift solenoid 6
4 and 66, overrunning clutch solenoid 8
2. A signal is output to the lock-up solenoid 56 and the line pressure solenoid 44.

In the control unit 300, FIG.
The shift control is performed according to the control flow shown in FIG. First, it is determined whether the vehicle speed sensor 302 is normal (step 102). Next, when the vehicle speed sensor 302 is normal, it is determined whether the vehicle speed is equal to or higher than the reverse prohibition vehicle speed V0 (104). Next, when the vehicle speed is equal to or higher than V0, it is determined whether or not the vehicle is in the reverse range.
6). Next, when the vehicle is in the reverse range, switching to the reverse gear is prohibited (108). Vehicle speed sensor 302
If is not normal, or if the vehicle speed is V0 or less, it is determined whether or not the vehicle is in the reverse range (110). Next, when the vehicle is not in the reverse range, the shift control is performed.
12) In the case of the reverse range, switching to the reverse gear is permitted (114).

When a failure of the vehicle speed sensor 302 is detected by the above control, the vehicle is allowed to move backward regardless of the vehicle speed. Therefore, even if the vehicle speed data held immediately before the failure of the vehicle speed sensor 302 is a vehicle speed higher than the reverse prohibition,
It is determined whether or not the vehicle is in the reverse range. If the vehicle is not in the reverse range, the shift control is performed. If the vehicle is in the reverse range, switching to the reverse gear is performed. The vehicle speed sensor 30
When the vehicle speed 2 is normal, when the vehicle speed exceeds the reverse prohibition speed, the switching from the forward range to the reverse range is prohibited, or the supply of oil to the friction element necessary for reverse movement is prohibited.

[0012]

As described above, according to the present invention, when the failure of the vehicle speed sensor is detected, the vehicle speed judging means
Is based on the vehicle speed data held by the vehicle speed sensor immediately before the failure.
The vehicle speed is determined based on the vehicle speed, and the reverse is permitted regardless of the determined vehicle speed. That is, even if the vehicle speed data held immediately before the failure of the vehicle speed sensor is equal to or higher than the reverse prohibition vehicle speed, the vehicle can move backward.

[Brief description of the drawings]

FIG. 1 shows the relationship between the components of the present invention.

FIG. 2 shows a skeleton of an automatic transmission.

FIG. 3 shows a combination of elements acting at each shift speed.

FIG. 4 shows the left half of the hydraulic circuit of the automatic transmission.

FIG. 5 shows the right half of the hydraulic circuit of the automatic transmission.

FIG. 6 shows an arrangement relationship between FIGS. 4 and 5;

FIG. 7 shows the left half of the control unit.

FIG. 8 shows the right half of the control unit.

FIG. 9 shows an arrangement relationship between FIGS. 7 and 8;

FIG. 10 shows a control flow.

[Explanation of symbols]

 302 Vehicle speed sensor

Continuation of front page (56) References JP-A-2-80860 (JP, A) JP-A-63-43054 (JP, A) JP-A-63-13949 (JP, A) JP-A-60-37446 (JP) JP-A-63-258234 (JP, A) JP-A-63-318353 (JP, A) JP-A-61-211564 (JP, A) JP-A-3-14964 (JP, A) 63-214548 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] 1. A vehicle speed sensor for detecting a vehicle speed, a vehicle speed judging means for judging whether or not the vehicle speed detected by the vehicle speed sensor is equal to or higher than a preset reverse prohibition speed, and a vehicle speed judging device for reducing the vehicle speed. When it is determined that the above is the case, the vehicle speed sensor is provided with a reverse prohibition unit that prohibits switching from the forward range to the reverse range or prohibits the supply of hydraulic pressure to the friction element required during reverse. There has speed sensor failure detecting means for detecting that failed, a failure of the vehicle speed sensor by the vehicle speed sensor failure detecting means is detected, vehicle speed sensor
Holds the vehicle speed data immediately before the failure, and the vehicle speed sensor
Said vehicle speed determination means based on the vehicle speed data immediately before the failure that
Reverse is permitted by reverse permission means regardless of the judgment.
A control device for an automatic transmission, wherein the control device is enabled .