JPH05346157A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To respectively prevent a stick slip in the case of a small load and a shock in the case of a large load when a select operation is performed in the condition of high engine speed by controlling oil pressure supplied to a friction coupling element according to the engine load. CONSTITUTION:The select operation of a select lever to a running position is detected by a select operation detecting means 1. At selection, the engine speed and the engine load are respectively detected by an engine speed at selection detecting means 2 and an engine load at selection detecting means 3. In this usual case, when the engine speed is under the decided value, oil pressure supplied to a friction coupling element is controlled by a usual oil pressure control means 4 so as to be in the standard value. In the case of small engine load, when the engine speed is over the decided value and the engine load is under the decided value, the oil pressure is controlled by an oil pressure at small engine load control means 5 so as to be higher than the standard value. In the case of large engine load, when the engine speed and the engine load are over the respective decided values, the oil pressure is controlled by an oil pressure at large engine load control means 6 so as to be lower than the standard value.

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 As a conventional control device for an automatic transmission, there is one disclosed in Japanese Patent Laid-Open No. 190660/1990. The control device for the automatic transmission shown in this figure is equipped with a starting clutch, etc. in order to prevent an excessive shift shock from occurring during a select operation from the N range to the D range with the accelerator pedal depressed. It is configured to reduce the line pressure supplied to the. That is, when the select operation is performed in a state where the engine speed is high, the hydraulic pressure supplied to the starting frictional engagement element is reduced for a predetermined time.

[0003]

However, in the above-described conventional automatic transmission control device, the hydraulic pressure is always temporarily reduced when the engine speed is high regardless of the throttle opening. Because it has been
Although it is possible to reduce the select shock, there is a problem that another problem occurs especially when the throttle opening is relatively small. In other words, since the hydraulic pressure supplied to the starting frictional engagement element is reduced, the starting frictional engagement element is about to be engaged by insufficient pressing force, and stick-slip (when the clutch or the like is in the engaged state). And a slipping condition are repeated intermittently) may occur. When stick slip occurs, abnormal noise is generated due to slippage of the friction engagement element.
The present invention aims to solve such problems.

[0004]

The present invention solves the above problems by controlling the hydraulic pressure of a friction engagement element for starting according to the engine load when a select operation is performed. That is, in the control device for the automatic transmission according to the present invention, the select operation detecting means (step 102) for detecting that the select lever is switched from the non-travel position to the travel position and the select operation is detected by the select operation detecting means. Engine rotation speed detection means at the time of selection for detecting the engine rotation speed (step 103)
And a select engine load detecting means (step 103) for detecting an engine load when the select operation detecting means detects the select operation, and an engine rotation speed detected by the select engine rotation speed detecting means is a predetermined value. In the following cases, the normal hydraulic pressure control means for controlling the friction engagement element supply pressure according to the reference value (step 10
8, 112), and when the engine speed is higher than the predetermined value and the engine load detected by the engine load detection means at the time of selection is less than or equal to a set value, the friction engagement element supply pressure is raised above the reference value. Small engine load hydraulic pressure control means (steps 108, 110, 116)
When the engine rotation speed is higher than the predetermined value and the engine load is higher than the set value, the large engine load hydraulic pressure control means (steps 108, 110) for lowering the friction engagement element supply pressure below the reference value. , 114)
And have.

[0005]

When the engine rotation speed when the select operation is performed is equal to or higher than the predetermined value, one of the following two controls is performed according to the engine load. That is, when the engine load is smaller than the set value, the hydraulic pressure supplied to the friction engagement element is set higher than the reference value.
On the other hand, when the engine load is larger than the set value, the hydraulic pressure is set lower than the reference value. As a result, when the engine load is relatively small, stick-slip of the frictional engagement element is prevented from occurring, and abnormal noise does not occur.
On the other hand, when the engine load is relatively large, the hydraulic pressure of the friction engagement element decreases, and the friction engagement element is gently engaged. This prevents a large shock from occurring.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
A description will be given based on 0. FIG. 2 is a skeleton view of a power transmission mechanism of an automatic transmission with four forward speeds and one reverse speed with overdrive. This power transmission mechanism is the torque converter 10
An input shaft 13 to which a rotational force is transmitted from an engine output shaft 12 via an output shaft 14, an output shaft 14 to transmit a driving force to a final drive device, 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 lockup 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 simultaneously meshes with both gears S1 and R1, and the planetary gear set 16 includes a sun gear S2 and an internal gear. It comprises a gear R2 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
It can be connected to the input shaft 13 via a reverse clutch 18. The carrier PC1 includes a forward clutch 22 and a forward one-way clutch 3 connected in series to 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, can also be connected to the internal gear R2. 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 can fix the carrier PC1, and the band brake 28 can be the sun gear S1.
Can be fixed. The low one-way clutch 29 is arranged in a direction in which the forward rotation of the carrier PC 1 (rotation in the same direction as the engine output shaft 12) is permitted but the reverse rotation (rotation in the forward rotation and the reverse direction) is not permitted.

The power transmission mechanism includes clutches 18, 2
0, 22 and 24, and brakes 26 and 28 in various combinations to operate the planetary gear sets 15 and 1
6 elements (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 the combination as shown in FIG. 3, the fourth forward speed and the first reverse speed can be obtained. Note that in FIG. 3, the circles indicate operating clutches and brakes, α1 and α2 are the 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, and the gear ratio is the output shaft. It is the ratio of the rotation speed of the input shaft 13 to the rotation speed of 14.

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, lockup 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, fast reducing valve 76, second shuttle valve 78, overrunning clutch control valve 80, overrunning clutch solenoid 8
2, overrunning clutch reducing valve 8
4, 1-2 accumulator 86, 2-3 accumulator 88, 3-4 accumulator 90, ND accumulator 92, accumulator control valve 94, filter 96, etc., and these are mutually connected as shown in the drawing. And the torque converter 10 described above.
(Note that the apply chamber 11a of the lock-up clutch 11 and the release chamber 11b are formed in this), the forward clutch 22, the high clutch 20, and the band brake 28 (in addition, the second speed apply chambers 28a, 3b).
A speed release chamber 28b and a fourth speed apply chamber 28c are formed), a reverse clutch 18, a low-and-reverse brake 26, and an overrunning clutch 24 are also connected as shown in the drawing, and a feedback accumulator 32 is further connected. Variable capacity vane type oil pump 34, oil cooler 36, front lubrication circuit 3 provided
7 and the rear lubrication circuit 38 are also connected as shown. Detailed description of these valves is omitted. Regarding the part of which description is omitted, it is disclosed in JP-A-63-251.
Similar to that described in 6521.

In FIGS. 7, 8 and 9, the 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) 1
5 and an output interface 316, which are connected by an address bus 319 and a data bus 320. This control unit 300 has
Engine rotation speed sensor 301, vehicle speed sensor 302, 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 A signal from 310 or the like is input. On the other hand, shift solenoids 64 and 66, overrunning clutch solenoid 82, lockup solenoid 5
6, and a signal is output to the line pressure solenoid 44.

The control when the select lever performs the select operation from the non-traveling position of the N or P range to the traveling position such as the D range is performed according to the control flow shown in FIG. First, it is determined whether or not the travel position has been selected (step 102), and if it has been selected, the vehicle speed V, the throttle opening TVO, and the engine speed N.
Read various signals such as E and select position.
3) Then, it is determined whether the vehicle speed V is equal to or lower than a predetermined value (step 104). When the vehicle speed V is equal to or lower than the predetermined value, it is determined whether the time T from the selection operation is equal to or lower than the predetermined value (at step 106). When the time T from the selection operation is equal to or less than the predetermined value, it is determined whether the engine speed NE is equal to or more than the predetermined value (108). If the engine speed is above a predetermined value, the throttle opening TVO
Determine whether (engine load) is greater than or equal to the set value. After that, it is determined whether the position after the operation of the select lever is in the two ranges or in a range other than the two ranges (at step 111). When the throttle opening TVO is smaller than the set value, the forward clutch 22 (this is the case for ND select, the reverse clutch 1 for NR select).
The line pressure, which is the hydraulic pressure supplied to 8), is set to a value higher than the reference value under the same operating condition (116). on the other hand,
When the throttle opening TVO is equal to or more than the set value and is outside the two ranges, the line pressure is set to a value lower than the reference value under the same operating condition (at 114). Also, the throttle opening TV
If O is equal to or greater than the set value and is in two ranges, step 114
The line pressure control and the overrunning clutch 24 release control are performed (step 115). When the engine speed NE is smaller than the predetermined value in step 108, the line pressure is set to the reference value (step 112).

As described above, when the throttle opening is relatively small, the line pressure is higher than the reference value. As a result, the forward clutch 22, which is a friction engagement element for starting, is securely engaged, and stick-slip does not occur. On the other hand, when the throttle opening is relatively large, the line pressure falls below the reference value, so the forward clutch 22 is gently engaged and a large shock is prevented. Further, when the throttle opening is relatively large and the range is two, in addition to lowering the line pressure, the overrunning clutch 2
Since 4 is released, when the select operation is directly performed from the N range to the 2 range, the overrunning clutch 24 is engaged before the forward clutch 22, and the accumulator that moderates the rising of the hydraulic pressure is used for this. When not, the torque is prevented from being suddenly transmitted, and the differential device or the like is not likely to be damaged. In the above embodiment, the engine load is detected from the throttle opening, but the intake pipe negative pressure,
Alternatively, the amount of intake air may be detected.

[0012]

As described above, according to the present invention, the hydraulic pressure is controlled according to the engine load when the select operation is performed in the high engine speed state, so that the engine load is relatively low. When it is small, the hydraulic pressure of the friction engagement element rises to prevent stick-slip from occurring. On the other hand, when the engine load is large, the hydraulic pressure decreases to prevent shock from occurring.

[Brief description of drawings]

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

FIG. 2 shows a framework of an automatic transmission.

FIG. 3 shows a combination of elements that act 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 a positional relationship between FIG. 4 and FIG.

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

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

FIG. 9 shows a positional relationship between FIGS. 7 and 8.

FIG. 10 shows a control flow.

[Explanation of symbols]

 300 Control unit 304 Select position switch

Claims (1)

[Claims] 1. A select operation detecting means for detecting that a select lever has been switched from a non-travel position to a travel position, and a select engine for detecting an engine rotation speed when the select operation is detected by the select operation detecting means. A rotation speed detecting means, a select engine load detecting means for detecting an engine load when the select operation is detected by the select operation detecting means, and an engine rotation speed detected by the select engine rotation speed detecting means is not more than a predetermined value. In the case of, the normal hydraulic pressure control means for controlling the friction engagement element supply pressure according to the reference value, the engine speed higher than the predetermined value, and the engine load detected by the engine load detection means during selection is equal to or less than the set value. In the case of, it is necessary to increase the friction engagement element supply pressure above the reference value. Engine load hydraulic pressure control means, and large engine load hydraulic pressure control for decreasing the friction engagement element supply pressure below a reference value when the engine speed is higher than the predetermined value and the engine load is higher than a set value. A means for controlling an automatic transmission.