JPH05106722A - Speed shift controller for automatic transmission - Google Patents

Abstract

PURPOSE:To remove the operation delay of a friction element to be fastened and prevent the worsening of a speed shift performance when speed shift is conducted by fastening a certain friction element by means of fastening pressure and at the same time releasing another friction element, by making the fastening pressure of a certain friction element set precharge pressure from a shift command till the start of a torque phase. CONSTITUTION:A signal from an input torque sensor 41 to detect transmission torque Ti, a signal from an output rotation number sensor 42 to detect a transmission output rotation number No, a signal from a throttle sensor 43, and a signal from a pressure sensor 44 to detect the fastening pressure POFF of a second brake 2/B, are inputted into a controller 40. When the substitution of a friction element for speed shift is conducted, the fastening pressure PON of another friction element brake 35R/B to be fastened in exchange for the friction element brake 2/B on a released side is made to be precharge pressure P simultaneously with a shift command till the start of a torque phase. As a result, the operation delay of the brake 35R/B is removed, and the worsening of a speed shift performance can be prevented.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Automatic transmissions have various friction elements (clutch,
It is possible to select a predetermined shift speed by selectively operating the hydraulic pressure of the brake) and to shift to another shift speed by switching the friction element to be operated.

Therefore, depending on the type of gear shift, there is a certain number of gear shifts, as seen from "2 → 3 gear shift of automatic transmission" in "NISSAN RE4F02A type automatic transaxle maintenance manual" issued by the applicant of the present application in March 1988. It is necessary to change the friction element that fastens the friction element (high clutch) and simultaneously releases the other friction element (band brake).

[0004]

By the way, the friction element to be engaged is more resistant to the spring force and sliding resistance of the return spring than the friction element to be released. When shifting is performed by changing the friction elements, this operation delay causes deterioration of shifting performance. It is an object of the present invention to apply a precharge pressure to a friction element to be engaged, thereby eliminating the above-mentioned problem of operation delay.

In this case, however, if the precharge pressure is too high or too low, the above problem cannot be solved sufficiently, or conversely, further deterioration of the shifting performance occurs. From this point of view, the present invention is configured to perform learning control of the above-mentioned precharge pressure to an appropriate value.

[0006]

To this end, the present invention is based on the concept of FIG. 1 of a friction element that fastens one friction element with a fastening pressure and at the same time opens another friction element by eliminating the fastening pressure. In an automatic transmission configured to change gears by changing gears, at the same time as the gear shift command, precharging means for setting the engagement pressure of the certain friction element to a set precharge pressure until the start of a torque phase, and a gear shift by this precharge. A pull-in torque detecting means for detecting pull-in of the machine output torque and a set pre-charge pressure correcting means for changing the set pre-charge pressure so that the pull-in torque becomes a predetermined value are provided.

[0007]

The automatic transmission performs a corresponding gear shift by engaging one friction element and at the same time changing the friction elements that release the other friction elements.

By the way, at the time of this shift, the precharge means sets the engagement pressure of the certain friction element to the set precharge pressure until the start of the torque phase at the same time as the command of the shift, so that the operation delay can be reduced. Even if the gear shifting is performed by changing the friction elements, the gear shifting performance is not deteriorated. Also, the set precharge pressure correction means is
The set precharge pressure is changed so that the pull-in torque due to the precharge detected by the pull-in torque detecting means becomes a predetermined value. Therefore, the precharge described above is performed without excess or deficiency, and the above-described operational effects can be reliably achieved.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows a gear transmission train of an automatic transmission that is shift-controlled by the device of the present invention, and a fastening logic table of friction elements related thereto.

Three first, second, and third planetary gear sets G1, G2, and G3 are coaxially arranged between the input and output shafts I and O, and these are respectively the first, second, third sun gear, and the third sun gear. A simple planetary gear set including first, second, and third ring gears and first, second, and third carriers. The first sun gear is connected to the input shaft I, the second and third sun gears can be connected to the input shaft by the low clutch L / C, and the second carrier can be connected to the input shaft by the high clutch H / C. The first carrier and the second ring gear can be integrally connected to each other and can be fixed with the second brake 2 / B, and the first ring gear can be the third speed / 5th speed / reverse band brake.
Can be fixed at 35R / B. Further, the second carrier is further integrally connected to the third ring gear so that the low reverse brake LR is
/ B can be used for fixing and low one-way clutch L / OWC is used to stop rotation in the direction opposite to the input shaft I.

In such a gear transmission train, the forward first to fifth speeds and the reverse speed can be selected by a combination of friction element engagement (marked with a circle) and release (no mark) shown in FIG. It is possible, and in FIG. 2, the chambers of the respective friction elements to which pressure is to be applied to obtain these engagements and disengagements are further shown by circles. In the logic table of FIG. 2, the symbol Δ indicates a friction element to be engaged and a chamber for supplying pressure for the purpose described later, though it does not participate in the selection of the shift speed.

FIG. 3 is a shift control hydraulic circuit for the gear transmission train shown in FIG. 2, which achieves the engagement logic of FIG. Reference numeral 10 denotes a manual valve, which is a forward automatic speed change range (D range), a first speed engine brake range (I range), a vehicle stop range (N range), or the like, depending on the traveling mode desired by the driver. It shall be manually operated to the reverse range (R range). The manual valve 10 also has a parking range (P range) and a second speed engine braking range (II range), but these are not related to the present invention and therefore omitted.

The manual valve 10 adjusts the line pressure P _L regulated by the pressure source 11 and output to the circuit 12 according to the selected range.
For range, port 10D, for I range, port 10D, 10
In the I range and the R range, the data is output to the port 10R, but in the N range, the line pressure circuit 12 is not connected to any port, and all the ports are drained.

Reference numerals 13, 14, and 15 denote first, second, and third duty solenoid valves, and 16 denotes a solenoid switching valve. A circuit 17 supplies a constant pilot pressure to these valves 13 to 16. This pilot pressure is measured by the pilot valve 18 on line P.
_Create by reducing _L to a constant value.

The duty solenoid valves 13 to 15 are further provided with
A forward pressure circuit 19 connected to the manual valve port 10D is connected, and this circuit 19 is further connected to the engagement chamber LC of the low clutch L / C.
Let A know.

The duty solenoid valves 13, 14 and 15 are all drained of the pilot pressure into the chambers 13a, 14a and 15a with a duty of 0%, and the positions shown in the drawings for draining the circuits 20, 21 and 22 are maintained, and the duty is 100%. %, The pressure in the chambers 13a, 14a, 15a rises to the same value as the pilot pressure, and the pressure in the circuits 20, 21, 22 is increased to the forward pressure circuit 19
Increase the pressure until it becomes the same value as the line pressure of.

The solenoid switching valve 16 supplies the pilot pressure of the circuit 17 at the time of ON to the switching valves 23 and 24 to move these valves to the right in the figure, and the switching valves 23 and 24 at the time of OFF are set to the positions shown in the drawing.
The switching valve 23 connects the circuit 20 to the circuit 25 and the circuit 20 to the right when connecting to the circuit 26 at the position shown. In addition, the switching valve 24 connects the second brake 2 / B to the circuit 25 and the high clutch H / C to the drain port 24a at the position shown in the drawing, and the right-hand second brake 2 / B to the drain port 24a and the high clutch H / C. Let C be connected to the output ports of the shuttle valve 27, respectively.

One input port of the shuttle valve 27 is a circuit 26
This circuit 26 is connected to the release chamber L of the low clutch L / C.
Band brake 35R / B 5 via CR and switching valve 28
Speed and retraction fastening room 5RA is also communicated. The other input port of the shuttle valve 27 is connected to the circuit 22, and the circuits 22 and 25 are connected via the shuttle valve 29 to the band brake 35R / B.
3rd of the band brake that communicates with the 4th speed release room 24R
The circuit 21 is connected to the fast and reverse fastening chamber 3RA.

The port 10I of the manual valve 10 is connected to the first speed engagement chamber 1A of the low reverse brake LR / B via the I range pressure reducing valve 30. Also, manual valve 10 port 10R
Is connected to the reverse engagement chamber RA of the low reverse brake LR / B by the circuit 31 and is also connected to the fifth speed and the reverse engagement chamber 5RA of the band brake 35R / B via the switching valve 28.

The valves 13 to 16 are controlled by the controller 40 shown in FIG. 4 as will be described later. For this purpose, the controller 40 receives a signal from the input torque sensor 41 for detecting the transmission torque T _i and the transmission output. detecting a signal from an output rotation sensor 42 that detects the rotational speed N _o, a signal from a throttle sensor 43 for detecting an engine throttle opening degree TH, the engagement pressure P _OFF of the second brake 2 / B as shown in the 3 A signal from the pressure sensor 44 is input. Based on these input information, the controller 40 controls the valves 13 to 16 as follows to execute the shift control of the automatic transmission, and the present invention aims at the 2 to 3 shift by the control program of FIGS. Shift control is enabled.

Next, the operation of the above-described embodiment will be described with reference to general shift control. In the N range of the manual valve 10,
The line pressure P _L of the circuit 12 is not output to any of the ports 10D, 10I, 10R, and all the ports are drained. Therefore, all the friction elements are deactivated (released), the automatic transmission does not transmit power between the input / output shafts I and O, and maintains the stopped state.

(First speed) When the forward travel is desired and the manual valve 10 is set to the D range, the line pressure P _L of the circuit 12 is output to the port 10D. This line pressure reaches the fastening chamber LCA of the low clutch L / C from the port 10D through the circuit 19.
Engage this clutch. On the other hand, when the vehicle is in a traveling state in which the first speed should be selected, the controller 40 of FIG. 4 sets the duty solenoid valves 13, 14, 15 to 0% duty and turns off the solenoid switching valve 16. Therefore, the circuit 20,
Since 21, 22 are not pressured and the switching valves 23, 24 are set to the positions shown in the drawing, the release chamber LCR of the low clutch L / C, the second brake 2 / B, the high clutch H / C and the band brake 35R / B are set. All rooms 3RA, 5RA, 24R are drained. Therefore, in the automatic transmission, only the low clutch L / C is engaged, and the first speed can be selected.

In the gear train of FIG. 2, engine braking cannot be obtained at the first speed due to the existence of the low one-way clutch L / OWC. If engine braking is required in the first speed, the driver sets the manual valve 10 to the I range to output the line pressure not only from the port 10D but also from the port 10I. At this time, the line pressure from the port 10I reaches the chamber 1A of the low reverse brake LR / B via the pressure reducing valve 30 (see the mark Δ in the table of FIG. 2), and this brake is additionally actuated to operate the engine at the first speed. Allows for braking.

(Second speed) D range In the first speed state,
When the operating state where the second speed should be selected, the controller 40
Gradually increases the duty of the first duty solenoid valve 13 to generate pressure in the circuit 20 and gradually increase this pressure. This pressure reaches the second brake 2 / B through the switching valves 23 and 24, and the second brake 2 / B is gradually engaged so that the upshift gearshift to the second speed can be performed without shock.

By the way, the engagement pressure of the second brake passes through the shuttle valve 29 and the release chamber 24R of the band brake 35R / B.
(Refer to the triangle mark in the table of FIG. 2), the band brake is prohibited from being engaged in cooperation with the return spring. Therefore, even if the duty solenoid valve 14 may generate pressure in the circuit 21 due to a failure of the control system, the band brake 35R / B is not engaged and the interlock of the automatic transmission prevents traveling. It can be avoided.

(Third speed) In the second speed state, when the operating state in which the third speed is to be selected is reached, the controller 40 reduces the duty of the first duty solenoid valve 13 and the circuit 20 (second brake 2 / B). The pressure of the second duty solenoid valve 14 is gradually increased and the pressure is generated in the circuit 21 (the chamber 3RA of the band brake 35R / B) and gradually increased in a manner described later with reference to FIGS. .. As a result, the second brake 2 / B is released, and the upshift gearshift to the third speed can be performed by changing the friction element with which the band brake 35R / B is engaged.

During this gear shifting, the engagement pressure of the released second brake 2 / B and the engagement pressure of the engaged band brake 35R / B are individually controlled by the duty solenoid valves 13 and 14, respectively. It is possible to freely set the release timing of the second brake 2 / B and the engagement timing of the band brake 35R / B to just the right timings according to the driving state as described later.

(4th speed) When the operation state in which the 4th speed is selected in the 3rd speed selection state, the controller 40 turns on the solenoid switching valve 16 to switch the switching valves 23 and 24 to the pilot pressure from the circuit 17, respectively. Switch to the rightward position in the figure, and at the same time gradually reduce the duty of the second duty solenoid valve 14
The pressure of 21 (the pressure in the fastening chamber 3RA of the band brake 35R / B) is reduced, and the duty of the third duty solenoid valve 15 is gradually increased to increase the pressure of the circuit 22 (via the shuttle valve 27 and the switching valve 24, the high clutch). The fastening pressure reaching H / C) is gradually increased. As a result, the band brake 35R / B is released, and the upshift gearshift to the fourth speed can be performed by changing over the friction elements with which the high clutch H / C is engaged.

A band brake that is released even during this gear shift
The engagement pressure in the chamber 35A of 35R / B and the engagement pressure of the high clutch H / C to be engaged are respectively determined by the duty solenoid valve.
It goes without saying that it can be controlled individually with 14, 15.

The high clutch engagement pressure of the circuit 22 reaches the release chamber 24R of the band brake 35R / B via the shuttle valve 29 (see the triangle mark in the table of FIG. 2), and the band brake works in cooperation with the return spring. Is prohibited. Therefore, even if the duty solenoid valve 14 causes pressure in the circuit 21 due to a failure of the control system, the band brake 35R / B is not engaged and the interlock of the automatic transmission is prevented. You can

(Fifth speed) When the fifth speed is selected in the fourth speed selection state, the controller 40 reduces the duty of the third duty solenoid valve 15 to decrease the pressure of the circuit 22, and 1st duty solenoid valve
The duty of 13 is increased to increase the pressure of the circuit 20. The pressure drop in the circuit 22 tries to release the high clutch H / C, but instead the pressure in the circuit 20 goes through the switching valve 23, the shuttle valve 27, the circuit 26 and the switching valve 24 to the high clutch H / C.
C is reached and high clutch H / C continues to be engaged. Circuit 26
At the same time, the pressure that reached the low clutch L / C release chamber L
Upon reaching CR, the pressure receiving area of this chamber is larger than the pressure receiving area of the chamber LCA, so that the low clutch L / C is released. The pressure in the circuit 26 is further passed through the switching valve 28 and the band brake is applied.
35R / B fastening room 5RA reached the brake release room 24
Since R is drained by the pressure drop in the circuit 22, the band brake 35R / B is engaged. As a result, the automatic transmission can perform upshift gear shifting to the fifth speed.

The duty solenoid valves 13, 14, 15 are also applicable to the 5 → 4 downshift shift, the 4 → 3 downshift shift, the 3 → 2 downshift shift, and the 2 → 1 downshift shift.
And the corresponding control of the solenoid directional control valve 16 gives the desired result.

(Reverse) When the driver wants to reverse and sets the manual valve 10 to the R range, the line pressure P _L of the circuit 12 is output to the circuit 31 by the port 10R and all the other ports become drains. Further, the controller 40 basically sets the duty of the duty solenoid valves 13, 14, 15 to 0% to put the circuits 20, 21, 22 in a non-pressure state, and sets the solenoid switching valve 16 to OF.
After that, the switching valves 23 and 24 are set to the positions shown in the figure.

On the one hand, the pressure of the circuit 31 reaches the engagement chamber RA of the low reverse brake LR / B to engage this brake, and on the other hand, it passes through the switching valve 28 to the engagement chamber 5RA of the band brake 35R / B to reach this band. Engage the brakes. Therefore, the automatic transmission can select reverse.

When it is desired to increase the brake capacity of the band brake 35R / B, such as when the accelerator pedal is suddenly depressed, the controller 40 increases the duty of the second duty solenoid valve 14 to generate pressure in the circuit 21 ( (Refer to the triangle in the table of FIG. 2). This pressure reaches the chamber 3RA and strengthens the fastening force of the band brake 35R / B, so that the brake capacity can be increased as required.

Next, description will be made of the shift control which the controller 40 executes according to the control program of FIGS.

[0037] FIG 5 is a main routine executed by the periodic interruption, first, it reads a throttle opening TH and the output speed N _o in step 51, then step 52
Calculating a vehicle speed V from N _o In. In the next step 53, the most suitable gear stage G _new for the current traveling state is determined from TH and V based on the planned map. Then, in step 54, it is determined whether or not the gear should be changed depending on whether or not the preferred gear is different from the currently selected gear G _old . If it is not necessary to shift, the control is returned to step 51 and the above loop is repeated to continue determining whether or not shifting is necessary.

When it is determined in step 54 that the gear should be changed,
In step 55, it is checked whether or not the shift of the present invention is the 2 → 3 shift, and if it is not the 2 → 3 shift, the normal shift is performed in step 56 as described above.

If it is the 2 → 3 shift, the control is advanced to step 57, the timer t is reset, and the elapsed time from the 2 → 3 shift command is measured. The elapsed time t, when explained by 2 → 3 shift operation time chart of FIG. 9, the shift command instant t ₀
Represents the time since. Next, in step 58, the shift phase is determined, and this routine is as shown in FIG.

That is, first, at step 71, the difference Δ between the transmission output speed N _o and the product value of the transmission input speed N _i and the gear ratio γ after shifting (the gear ratio of the third speed in this case). N

[Formula 1] ΔN = N _o −N _i × γ ... (1) This ΔN represents the slip amount of the friction element (brake 35R / B in this case) that is engaged during the shift, that is, the degree of progress of the shift. In the next step 72, it is checked whether or not the shift is completed, depending on whether or not the absolute value of the rotation difference ΔN is less than the minute set value ΔN _s. If not, in step 73, the timer measurement time is calculated. t is shown in FIG.
It is checked whether or not it is less than a predetermined precharge time t ₁ shown in ( _1). If t <t ₁ , the gear shift phase is set to the precharge phase in step 74. If the precharge phase of t ≧ t ₁ ends, it is checked in step 75 whether or not the torque phase time shown in FIG. 9 is t ₂ by t <t ₁ + t ₂ , and if so, in step 76. If the gear shift phase is the torque phase, otherwise, in step 77, the gear shift phase is also set to the inertia phase shown in FIG. Then, when it is determined in step 72 that the shift is completed, in step 78, the shift phase is set to the end phase so as to represent this.

At the next step 59 in FIG. 5, it is checked whether the shift phase determined as described above is the end phase or not. Until the end phase, the loop for returning to step 59 through steps 60 and 61 is repeated to control the engagement pressure P _ON of the brake 35R / B to be engaged at the time of the gear change as shown in FIG. 9 and release it. The engagement pressure P _OFF (hereinafter referred to as release pressure) of the brake 2 / B to be reduced is similarly controlled as shown in FIG.

The release pressure control routine of step 61 is 2 →
The release pressure P _OFF is controlled in the same manner as described above for the three-speed shift operation to reduce it as shown in FIG.
60 engagement pressure control routine shall as shown in FIG. 7 in light of the purpose of the present invention, this by engagement pressure P _ON 9
Raise as shown in.

In FIG. 7, it is checked in steps 81 to 83 whether it is a precharge phase, a torque phase, an inertia phase or an end phase. In the precharge phase, in step 84, the engagement pressure P _ON is set to a preset precharge pressure P _P which can be changed as described later. Next, in steps 85 and 86, the minimum value T _OP of the transmission output torque T _O during the precharge phase is continuously updated and obtained as shown in FIG.

During the next torque phase, the engaging pressure is increased at a predetermined speed in step 87 as shown in FIG. 9, and during the inertia phase, the engaging pressure is increased to the predetermined shelf pressure illustrated in FIG. 9 at step 88. And eggplant

When the end phase is determined in step 59 of FIG. 5, the engagement pressure P _ON is set to the maximum line pressure P _L as shown in FIG. 9 in step 62, and step 63
Then, the present transmission output torque T _O is set to the end phase output torque T _OE as shown in FIG. 9, and thereafter, in step 64, the precharge pressure P _P is learned and controlled.

The learning control in step 64 is as shown in FIG. 8. In step 91, the transmission output torque during the precharge phase (pull-in torque due to precharge) T _OP is the transmission output torque T _OE during the end phase. It is checked whether or not they are less than each other, and in step 92, it is checked whether the pull-in torque is larger than the end phase torque or both are equal.

If the precharge pressure P _P is too high, as shown by the chain double-dashed line in FIG. 9, the torque pull-in is large and a feeling of deceleration is generated, which deteriorates the gear shifting performance as compared with the case where the precharge pressure is not applied, and is low. too the purpose can not sufficiently achieve the present invention, to reduce the pre-charge pressure only △ P _P in T _OP <T _OE If step 93 only precharge pressure high, conversely only the pre-charge pressure is low T _OP increasing the precharge pressure only △ P _P in> T _OE if step 94. If T _OP = T _OE , the precharge pressure is not changed by returning the control from step 92 to the main routine of FIG.

According to the above engagement pressure control, as shown in FIG. 9, the engagement pressure P _ON becomes the precharge pressure P _P until the start of the torque phase at the same time as the gear shift command. Brake to be engaged in exchange for release of
The 35R / B can be engaged without an operation delay, and the gear shifting performance is not deteriorated even when the gear shifting is performed by changing friction elements. Further, since the pre-charge pressure is learned and controlled so that the pull-in torque T _OP matches the torque T _OE at the end of the shift, the pre-charge can be performed without excess or deficiency, and the above-described operational effects can be reliably achieved. You can

In the above example, the precharge pressure is learned and controlled so that the pull-in torque has a predetermined value. However, since the pull-in torque causes a change in the acceleration of the vehicle, it is detected by the front-back G sensor 45 in FIG. It goes without saying that the precharge pressure may be learned and controlled so that the acceleration G does not occur.

[0050]

As described above, in the shift control device of the present invention, when the friction element is changed for shifting, the friction element to be released (the brake 2 / B in the illustrated example) and another friction element to be engaged in exchange ( In the illustrated example, the engagement pressure P _ON of the brake 35R / B) is set to the pre-charge pressure P _P until the start of the torque phase at the same time as the gear shift command. Therefore, the latter operation delay of the friction element is eliminated and the gear shifting performance accompanying this is eliminated. Can be prevented from worsening. Further, since the learning control is performed so that the pre-charge pressure is such that the pull-in torque due to the pre-charge becomes a predetermined value, the action and effect can be secured.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a shift control device of the present invention.

FIG. 2 is a skeleton diagram illustrating a gear transmission train of an automatic transmission in which gear shifting is controlled by the device of the present invention, and a friction element engagement logic table thereof.

FIG. 3 is a circuit diagram showing a shift control hydraulic circuit of the transmission train.

FIG. 4 is a block diagram showing an electronic control system of the hydraulic circuit.

FIG. 5 is a flowchart showing a main routine of a control program executed by a controller of the electronic control system.

FIG. 6 is a flowchart showing a subroutine in the program.

FIG. 7 is a flowchart showing a subroutine in the program.

FIG. 8 is a flowchart showing a subroutine in the program.

FIG. 9 is a time chart of a shift operation by the control of FIGS.

[Explanation of symbols]

 I Input shaft O Output shaft G1 1st planetary gear set G2 2nd planetary gear set G3 3rd planetary gear set L / C Low clutch H / C High clutch 35R / B Band brake 2 / B Second brake LR / B Low reverse brake L / OWC Low one-way clutch 10 Manual valve 11 Pressure source 13 First duty solenoid valve 14 Second duty solenoid valve 15 Third duty solenoid valve 16 Solenoid switching valve 18 Pilot valve 23 Switching valve 24 Switching valve 28 Switching valve 30 I range decompression Valve 40 Controller 41 Input rotation sensor 42 Output rotation sensor 43 Throttle sensor 44 Output torque sensor 45 Front and rear G sensor

Claims (1)

[Claims] 1. An automatic transmission in which a certain friction element is engaged with an engagement pressure and at the same time another friction element is opened by exchanging the engagement pressure to perform a gear shift. At the same time, until the start of the torque phase, precharging means for setting the engagement pressure of the certain friction element to the set precharge pressure, pull-in torque detecting means for detecting pull-in of transmission output torque due to this pre-charge, and the pull-in torque is predetermined. A shift control device for an automatic transmission, comprising: a set precharge pressure correction means for changing the set precharge pressure so that the set value becomes a value.