JPH09273625A - Speed change controller for vehicular automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller for an automatic transmission, for preventing shock to be generated caused by the engagement of a one-way clutch in the driving stage after coast downshift. SOLUTION: In a controller for an automatic transmission, to be downshifted to the set stage of speed by engaging a one-way clutch arranged parallel to a frictional engaging device when the output of a driving power source is deceased into the non-driving state, the non-driving state by drop in output of the driving power source is detected (step 1). Downshift to the stage of speed in which the one-way clutch is to be engaged is detected by a change of the traveling state including drop in vehicular speed in the non-driving speed. When downshift is detected, the frictional engaging device arranged parallel to the one-way clutch is engaged (steps 3, 5).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling a shift in an automatic transmission for a vehicle, and particularly to a one-way clutch arranged in parallel with a friction engagement device when in a non-driving state. The present invention relates to a device for controlling a shift of an automatic transmission that causes a downshift to a low speed stage that is set by being engaged.

[0002]

2. Description of the Related Art As is well known, an automatic transmission for a vehicle is configured to set a shift speed suitable for each traveling state based on a traveling state such as a throttle opening and a vehicle speed. The shift is executed based on the shift map that defines the shift speed region according to the traveling state and the input data. Therefore, since the running performance (driving performance) of the vehicle changes depending on the shift map, in the past, a shift map with the upshift line set to the low vehicle speed side and a run with emphasis on acceleration were performed in order to run with emphasis on fuel efficiency. In order to do this, a shift map with the upshift line set to the high vehicle speed side and a shift map used for normal driving are provided, and the shift map can be switched based on the driver's selection operation or accelerator operation. It is being appreciated.

Further, in order to increase the action of engine braking, the shift map or its specific shift line is also changed. For example, in the invention disclosed in Japanese Patent Application Laid-Open No. 2-46354, the throttle opening is changed. The downshift line is set so as to protrude toward the high speed side at a portion where the opening is equal to or less than the predetermined opening. That is, according to the invention described in this publication, even when the vehicle speed is high to some extent, the throttle opening is reduced to positively execute the shift to the low speed stage, thereby setting the engine as a driven state and engine braking. Is controlled so that

[0004]

By the way, it is widely practiced to set a low-speed gear in an automatic transmission for a vehicle by engaging a one-way clutch. In other words, when upshifting from a low speed stage that is set in a high torque state such as when starting, complicated and accurate control is required to eliminate the shift shock in the power-on state, so it automatically changes with torque change. A one-way clutch that disengages is used to facilitate shift control.

As in the conventional automatic transmission described above, the low speed stage, which is positively set by setting the downshift line at the low throttle opening to the high vehicle speed side, engages the one-way clutch. If the shift speed is set according to the above, the down-shift occurs due to the throttle opening decreasing at a relatively high vehicle speed, and the low speed is set with the one-way clutch released. In this state, the automatic transmission is not transmitting torque. Even in that case, since the engine is driven in the idling state, when the vehicle speed further decreases, the driving force from the engine is input to the automatic transmission and the state is switched to the so-called power-on state. As a result, the released one-way clutch is engaged, and torque is generated in the output shaft. Such a situation also occurs when the accelerator pedal is slightly depressed again after the downshift.

When the one-way clutch is engaged as described above, the torque of the output shaft of the automatic transmission changes from a negative torque to a positive torque, and in particular, an interlaced shift from the middle speed stage such as the third speed. When the gear is downshifted to the first speed by, the range of change in the torque becomes large. Therefore, the output torque increases due to engagement of the one-way clutch after the downshift, which may cause a shock.

The present invention has been made in view of the above circumstances, and provides a control device capable of improving a shock caused by engagement of a one-way clutch that sets a gear after a coast downshift. That is the purpose.

[0008]

In order to achieve the above-mentioned object, the invention described in claim 1 is a frictional engagement when the output of the driving force source is lowered to a non-driving state. In a shift control device for a vehicular automatic transmission that is downshifted to a shift speed set by engaging a one-way clutch arranged in parallel with the device, a non-driving state for detecting a non-driving state due to a reduction in output of a driving force source State detection means, downshift detection means for detecting a downshift to a shift stage in which the one-way clutch is engaged by a change in the running state including a decrease in vehicle speed in a non-driving state, and the downshift detection means When a downshift is detected, the one-way clutch is further provided with engagement control means for executing control for engaging the friction engagement device arranged in parallel. It is.

Therefore, according to the first aspect of the present invention, the vehicle speed decreases as the output of the driving force source such as the engine decreases, and as a result, when the downshift is executed, the shift speed after the downshift is set. Control for engaging the frictional engagement devices arranged in parallel with the one-way clutch is executed. This friction engagement device is provided to make the engine brake effective, and is normally engaged in the engine brake range. Instead, it is engaged even during a downshift due to a change in running state such as vehicle speed. As a result, when the non-driving state is changed to the driving state, the torque carried by the one-way clutch is applied to the friction engagement device, so that the engagement of the one-way clutch and the shock resulting therefrom are eliminated or reduced.

According to a second aspect of the present invention, the engagement control means sets the torque capacity of the friction engagement device to a torque capacity lower than the torque capacity required to set a shift stage for engaging the one-way clutch. It is characterized by including a means for controlling.

Therefore, according to the second aspect of the present invention, since the torque capacity of the friction engagement device is low, the engine braking does not work immediately even if the friction engagement device engages with a downshift. Even if the one-way clutch is engaged when the non-driving state is switched to the driving state, the width of change in torque before and after that is small,
Shock is reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described. First, an example of an engine E and an automatic transmission A to which the present invention is applied will be described. FIG. 3 is an overall control system diagram, and the engine E to which the automatic transmission A is connected has its intake pipe. The path 12 has a main throttle valve 13 and a sub-throttle valve 14 located upstream thereof. The main throttle valve 1
Reference numeral 3 is connected to the accelerator pedal 15 and is opened / closed in accordance with the depression amount of the accelerator pedal 15. The sub throttle valve 14 is adapted to be opened and closed by a throttle actuator 16 such as a servo motor.

The throttle actuator 16 is controlled to adjust the opening of the sub-throttle valve 14,
In addition, an engine electronic control unit (E-ECU) 17 for controlling the fuel injection amount and ignition timing of the engine E
Is provided. The electronic control unit 17 includes a central processing unit (CPU) and storage devices (RAM, ROM).
In addition, the electronic control unit 17 mainly includes an input / output interface, and the electronic control unit 17 has engine (E / G) rotation speed N, intake air amount Q,
Intake air temperature, throttle opening, vehicle speed, engine water temperature,
Various signals such as a signal from a brake switch are input.

In the automatic transmission A, the hydraulic control device 18 controls gear shifting and lockup clutch, line pressure, or engagement pressure of a predetermined friction engagement device. The hydraulic control device 18 is configured to be electrically controlled, has first to third shift solenoid valves S1,..., S3 for performing a shift, and has a first for controlling an engine brake state. 4 solenoid valve S4, linear solenoid valve SLT for controlling line pressure, linear solenoid valve SLN for controlling accumulator back pressure, linear for controlling engagement pressure of a lock-up clutch or a predetermined friction engagement device. A solenoid valve SLU is provided.

An electronic control unit (T-ECU) 19 for an automatic transmission that outputs a signal to these solenoid valves to control gear shift, line pressure, accumulator back pressure, etc.
Is provided. This electronic control unit for automatic transmission 19
Is a central processing unit (CPU) and a storage device (RA
M, ROM) and an input / output interface, and this electronic control unit 19 indicates throttle opening, vehicle speed, engine water temperature, signals from brake switch, and shift position as data for control. Signal, signal from pattern select switch, signal from overdrive switch, clutch C described later
A signal from a C0 sensor that detects the rotational speed of 0, an oil temperature of the automatic transmission, a signal from a manual shift switch, and the like are input.

The electronic control unit 19 for the automatic transmission and the electronic control unit 17 for the engine are connected to each other so that data can be communicated with each other, and the electronic control unit 17 for the engine transfers to the electronic control unit 19 for the automatic transmission. On the other hand, a signal such as the intake air amount per rotation (Q / N) is transmitted, and an instruction signal for each solenoid valve is sent from the automatic transmission electronic control unit 19 to the engine electronic control unit 17. A signal equivalent to, a signal instructing a shift speed, and the like are transmitted.

That is, the electronic control unit 19 for the automatic transmission
Is based on input data and a map stored in advance, and indicates ON / OF of a gear position and a lock-up clutch.
F, or the pressure regulation level of the line pressure or the engagement pressure is determined, and an instruction signal is output to a predetermined solenoid valve based on the result of the determination, and further, a failure determination and control based on the failure are performed. . In addition to controlling the fuel injection amount, the ignition timing, the opening degree of the sub-throttle valve 14, etc. based on the input data, the electronic control unit 17 for the engine also sets the fuel injection amount during the shift in the automatic transmission A. The output torque is temporarily reduced by reducing the amount, changing the ignition timing, or narrowing the opening of the sub-throttle valve 14.

FIG. 4 is a diagram showing an example of a gear train of the above-described automatic transmission A, and in the configuration shown here, it is configured to set five forward gears and one reverse gear. That is, the automatic transmission A shown here is
, A sub transmission unit 21 and a main transmission unit 22. The torque converter 20 includes a lock-up clutch 23
The lock-up clutch 23 has a front cover 25 integrated with the pump impeller 24.
(Hub) 2 integrally mounted with the turbine runner 26
7 is provided. An engine crankshaft (each not shown) is connected to a front cover 25 and an input shaft 28 to which a turbine runner 26 is connected.
Is connected to the carrier 30 of the overdrive planetary gear mechanism 29 that constitutes the subtransmission portion 21.

The carrier 3 in this planetary gear mechanism 29
A multi-plate clutch C0 and a one-way clutch F0 are provided between the first gear 0 and the sun gear 31. The one-way clutch F0 is engaged when the sun gear 31 rotates forward relative to the carrier 30 (rotation in the rotation direction of the input shaft 28). A multi-disc brake B0 for selectively stopping the rotation of the sun gear 31 is provided.
The ring gear 3 which is an output element of the subtransmission portion 21
2 is connected to an intermediate shaft 33 which is an input element of the main transmission unit 22.

Therefore, in the auxiliary transmission portion 21, the entire planetary gear mechanism 29 rotates integrally when the multi-plate clutch C0 or the one-way clutch F0 is engaged, so that the intermediate shaft 33 has the same speed as the input shaft 28. At low speed. When the brake B0 is engaged and the rotation of the sun gear 31 is stopped, the speed of the ring gear 32 is increased with respect to the input shaft 28 and the ring gear 32 is rotated forward, so that a high gear is established.

On the other hand, the main transmission section 22 has three sets of planetary gear mechanisms 40, 50, and 60, and their rotating elements are connected as follows. That is, the sun gear 41 of the first planetary gear mechanism 40 and the sun gear 51 of the second planetary gear mechanism 50 are integrally connected to each other, and the ring gear 43 of the first planetary gear mechanism 40 and the carrier 52 of the second planetary gear mechanism 50 are connected to each other. The three members of the third planetary gear mechanism 60 and the carrier 62 are connected, and the output shaft 65 is connected to the carrier 62. Further, the ring gear 53 of the second planetary gear mechanism 50 is connected to the sun gear 61 of the third planetary gear mechanism 60.

In the gear train of the main transmission unit 22, it is possible to set a reverse gear and four gears on the forward side, and clutches and brakes therefor are provided as follows. First, the clutch will be described. The ring gear 53 of the second planetary gear mechanism 50 and the third gear
A first clutch C1 is provided between the sun gear 61 of the planetary gear mechanism 60 and the intermediate shaft 33, and the sun gear 41 of the first planetary gear mechanism 40 and the sun gear 51 of the second planetary gear mechanism 50 and the intermediate shaft are connected to each other. A second clutch C2 is provided between the clutch 33 and the second clutch C2.

Next, the brake will be described. The first brake B1 is a band brake, and the sun gears 41, 5 of the first planetary gear mechanism 40 and the second planetary gear mechanism 50.
It is arranged to stop the rotation of 1. A first one-way clutch F1 and a second brake B2, which is a multi-plate brake, are arranged in series between the sun gears 41 and 51 (that is, the common sun gear shaft) and the casing 66. One-way clutch F1 has sun gears 41 and 5
1 is engaged when it is about to rotate in the reverse direction (rotation in the direction opposite to the rotation direction of the input shaft 28).

A third brake B3, which is a multi-plate brake, is provided between the carrier 42 of the first planetary gear mechanism 40 and the casing 66. As a brake for stopping the rotation of the ring gear 63 of the third planetary gear mechanism 60, a fourth brake B4, which is a multi-plate brake, and a second one-way clutch F2.
Are arranged in parallel with the casing 66. The second one-way clutch F2 is adapted to be engaged when the ring gear 63 is about to rotate in the reverse direction.

In the above-described automatic transmission A, it is possible to set five forward speeds and one reverse speed by engaging and disengaging each clutch and brake as shown in the operation table of FIG. In FIG. 5, a circle indicates an engaged state, a circle indicates an engaged state during engine braking, a circle indicates that the engine is engaged in the engine brake range and selectively engaged in another range, and a triangle indicates an engaged state. It may be either combined or released, and the blanks indicate the released state.

Describing the range, the automatic transmission A described above has a parking (P) range, a reverse (R) range, a neutral (N) range, a drive (D) range, a "4" range, and a "3". A range, a "2" range, and a low (L) range are provided, and these are selected by operating a shift lever (not shown). As shown in FIG. 6, the arrangement of these shift devices is such that the P range position and the R range position are arranged in a straight line in order from the front side of the vehicle, and the N range position is located diagonally to the right rear of the R range. Are arranged. A D range position is provided behind the N range position.
The "4" range position is arranged on the left side of the range position, and the "3" range position is arranged behind the "4" range position. The "2" range position is arranged diagonally left behind the "3" range position, and the L range position is arranged on the left side of the "2" range position. Each of these range positions is connected by a groove that guides the shift lever.

The P range is a range in which the vehicle is maintained in a stopped state, and the automatic transmission A is in a neutral state by closing all output ports of a manual valve (not shown) operated by the shift device. Further, the rotation of the output shaft 65 is mechanically blocked by the lock poles (not shown) engaging the parking gear integrated with the output shaft 65. In the R range, the hydraulic pressure for setting the reverse gear is output from the manual valve, and the first to third solenoid valves S1 to S3 are used.
Is operated to send hydraulic pressure to a predetermined shift valve (not shown), and as shown in FIG. 5, the second clutch C2, the brake B0 of the auxiliary transmission portion 21, and the fourth brake B4 are engaged.

In the N range, similar to the P range, all the output ports of the manual valve (not shown) are closed, so that the automatic transmission A is in the neutral state.
In the D range, all forward speeds from the first speed to the fifth speed can be set, and in the speeds lower than the third speed, the friction engagement device in parallel with the one-way clutch is maintained in the released state. , Engine brake doesn't work. In the "4" range, you can set the gear up to the 4th speed,
In the "3" range, the gears up to the third speed can be set, and the first brake B1 is engaged at the third speed, so that the engine braking is effective at the third speed. Further, in the "2" range, the shift speed up to the second speed can be set, and the engine braking is effective by engaging the clutch C0 at the second speed. Then, in the L range, only the first speed is set, and by engaging the fourth brake, it becomes the first speed at which engine braking is effective.

In the above-described automatic transmission A, when performing the shift between the second speed and the third speed as is known from the engagement state of the friction engagement device at each shift stage shown in FIG. , The second brake B2 and the third brake B3 are both engaged and released. This is a so-called clutch-to-clutch shift, and its control needs to control the torque capacity (hydraulic pressure) of both depending on the shift progress state, input torque, etc., and complicated control is required. Therefore, in the above-described automatic transmission A, the clutch-to-clutch shift is performed in the coast downshift from the third speed in the D range, that is, the downshift from the third speed in the idle state with the throttle opening fully closed. Avoid it and control to shift to the first speed.

This coast downshift to the first speed is executed by releasing the first brake B1 as is known from FIG. 5, but the automatic transmission A is operated because the engine is idling. In the non-driving state, that is, when the input rotation speed is smaller than the product of the gear ratio of the first speed and the output shaft rotation speed, the second one-way clutch F2 is maintained in the released state and the third planetary gear F3 is released. Gear mechanism 6
No reaction torque is applied to the zero ring gear 63. However, when this state continues and the vehicle speed further decreases, or when the accelerator pedal is depressed and the engine is in the idling off state, the torque input from the engine increases and the second one-way clutch F2 is engaged. In that case,
Before the gear shift was the third speed, the gear position where the output torque appears when the second one-way clutch F2 is engaged is the first gear, and the gear ratio is considerably large. The increase in output torque caused by the engagement of the one-way clutch F2 may be significant.

In order to prevent a sudden increase in the output torque due to the engagement of the second one-way clutch F2 in the substantial power-on state after such a coast downshift, the control device of the present invention uses the second Fourth parallel with one-way clutch F2
The brake B4 is controlled as described below. Therefore, first, a mechanism for controlling the torque capacity of the fourth brake B4, that is, the engagement pressure will be described.

In FIG. 7, the signal pressure PSL of the linear solenoid valve SLN for controlling the accumulator back pressure is controlled.
N is supplied to the input port 71 of the accumulator control valve 70. The accumulator control valve 70 is the linear solenoid valve S.
It is a valve for adjusting the signal pressure PSLN output by LN based on the throttle opening, and at a pressure adjustment level according to the signal pressure PSLT of the linear solenoid valve SLT whose duty ratio is controlled based on the throttle opening. The pressure is regulated and the accumulator back pressure PACC is output from the output port 72.

The accumulator back pressure PACC is supplied to the control port 74 of the coast brake control valve 73. The coast brake control valve 73 is a valve that regulates the output pressure by opposing the output pressure to the elastic force of the spring 75 and the accumulator back pressure PACC, and the D range pressure output in the D range is input. An output port 77 selectively connected to the input port 76 is connected to the feedback port 78. Further, its output port 77 is connected to the input port 80 of the coast brake relay valve 79.

This coast brake relay valve 79
Is a valve that connects the input port 80 to the output port 81 when the signal pressure or the predetermined range pressure of the fourth solenoid valve S4 is supplied, and the output port 81 is the input port 83 of the 2-3 shift valve 82. It is connected to the.

The 2-3 shift valve 82 is a valve that is switched when shifting between the second speed and the third speed, and the communication state of the input port 83 with other ports is as follows.
It is schematically shown below the 2-3 shift valve 82 in FIG. That is, the input port 83 is communicated with the output port 84 in the first speed, the second speed, the N range, and the R range. Furthermore, this output port 84 is a 1-2 shift valve 8
5 is connected to the input port 86. The 1-2 shift valve 85 is a valve for executing a shift between the first speed and the second speed. The communication state between the input port 86 and other ports is 1-2 in FIG. It is schematically shown below the shift valve 85. That is, the input port 86 is the first
It communicates with the output port 87 in the speed and N range and the R range. The output port 87 is connected to the fourth brake B4 via the shuttle valve 88.

Therefore, the fourth solenoid valve S4 is turned off.
In the N state, the oil passage from the coast brake control valve 73 to the fourth brake B4 communicates with the first speed and the N range and the R range.
Since the range pressure is output at the first speed, the hydraulic pressure is eventually supplied to the fourth brake B4 at the first speed and the fourth brake B4 is engaged. The engagement pressure is the linear solenoid valve SLN.
Is controlled by changing the pressure regulation level of the coast brake control valve 73.

FIG. 1 conceptually shows an engagement control routine of the fourth brake B4 executed at the time of coast downshift to the first speed using the hydraulic circuit shown in FIG.
In this control, first, a coast downshift from the third speed to the first speed is determined (step 1). Specifically, this is because the idle switch is ON (non-driving state), and the shift signal (signal for switching the shift solenoid valve) for setting the first speed is output in the third speed state. It can be judged based on the above. The so-called interlaced shift from the third speed to the first speed is performed by the above-described automatic transmission A which is a clutch-to-clutch shift between the second speed and the third speed. This is because the control becomes complicated in order to improve the shock of. Therefore, this step 1 corresponds to the non-driving state detecting means and the downshift detecting means of the present invention.

When a negative determination is made in step 1, that is, when the coast downshift from the third speed to the first speed is not determined, the routine returns, and when the coast downshift is determined, It is determined whether or not the next gear shift, that is, the shift to another gear is to be executed (step 2). This can be determined by the fact that the traveling state has entered a shift speed region other than the first speed due to the fact that the vehicle speed increases as the user goes down a slope. And this step 2
If the determination is affirmative, the routine returns without performing any control. On the other hand, if the determination is negative, that is, if the first speed is maintained, the engagement control of the fourth brake B4 is executed. (Step 3).

As described above, the fourth brake B4 is
A friction engagement device for engine braking, which is arranged in parallel with the second one-way clutch F2 for setting the first speed after the coast downshift, and is executed by controlling the ON of the fourth solenoid valve S4. As shown in FIG. 7, in the first speed, the input port 8 of the 2-3 shift valve 82
3 and the output port 84 communicate with each other, and the input port 86 and the output port 87 of the 1-2 shift valve 85 communicate with each other, so that the hydraulic pressure can be supplied from the coast brake relay valve 79 to the fourth brake B4. Has become. Therefore, in this state, if the fourth solenoid valve S4 is ON-controlled to supply the signal pressure to the control port of the coast brake relay valve 79 so that the input port 80 and the output port 81 are communicated with each other, the D range pressure is increased. The hydraulic pressure used as the original pressure is supplied to the fourth brake B4.

The hydraulic pressure thus supplied to the fourth brake B4 is regulated by the linear solenoid valve SLU and the coast brake control valve 73,
As a result, the fourth brake B4 is set in the so-called half-engaged state. That is, the input rotation speed NC0 is detected, and it is determined whether or not this rotation speed is within a certain range which is lower than the synchronous rotation speed of the first speed (step 4). Specifically, whether the input speed is within the range of the value obtained by multiplying the output speed NO by two coefficients k1, k2 (> k1) smaller than the gear ratio of the first speed (k1.NO <N
Judge C0 <k2.NO). This range is shown in FIG.

If the negative determination is made in step 4 because the input rotational speed NC0 is not within this range, a predetermined correction value α is added to or subtracted from the duty ratio DSLN of the linear solenoid valve SLN (step 5). Then, the control of step 5 is executed until the input rotational speed NC0 falls within the above range. That is, the duty ratio DSLN of the linear solenoid valve SLN is feedback-controlled based on the input rotation speed NC0. When the affirmative judgment is made in step 4, the process returns.

Therefore, in the control shown in FIG. 1, the fourth brake B4 is controlled to the half-engaged state so that the input rotation speed NC0 is maintained at a predetermined rotation speed lower than the synchronous rotation speed of the first speed. In this case, the torque capacity of the fourth brake B4 is kept lower than the capacity required to set the first speed, so that the fourth brake B4 is slipping. As a result, the first speed is not completely achieved, so that the coast braking (engine braking) state and the accompanying shock are prevented.

When the fourth brake B4 is in the so-called half-engaged state, the reaction torque is given to the ring gear 63 of the third planetary gear mechanism 60 to some extent, so that the output torque is increased accordingly. There is. Therefore, when the non-driving state changes to the driving state due to a decrease in vehicle speed or a slight increase in the throttle opening, and the second one-way clutch F2 is engaged accordingly, the second one-way clutch F2 becomes Insufficient reaction torque due to the incomplete engagement of the fourth brake B4, that is, reaction torque generated when the semi-engaged state is changed to the fully engaged state is generated.

The output torque increases accordingly, but the increase amount of the torque is not the increase amount generated by engaging the second one-way clutch F2 from the released state with the fourth brake B4 released. Instead, the fourth brake B4 is in a semi-engaged state in advance and is increased to some extent, which is an increase amount of the shortage. In other words, the second one-way clutch F2
The amount of increase in the output torque caused by the engagement of the second clutch is suppressed, and the shock caused by the engagement of the second one-way clutch F2 is reduced.

Particularly, in the above-described automatic transmission A, the clutch-to-clutch shift is avoided and the coast downshift is performed from the third speed to the first speed, so that the gear ratio in the first speed after the shift becomes large. Although the increase amount of the output torque increases due to the engagement of the one-way clutch, the friction engagement device arranged in parallel with the one-way clutch as described above, that is, the friction engagement device for the engine brake is semi-engaged in advance. Since the output torque is increased to some extent in the combined state, it is possible to effectively prevent a sudden increase in the output torque, that is, a shock due to the engagement of the one-way clutch. Note that steps 3 and 5 shown in FIG. 1 correspond to the engagement control means of the present invention.

The present invention is not limited to the specific examples described above, and can be similarly applied to the case of downshifts other than the coast downshift from the third speed to the first speed. In that case, the friction engagement device arranged in parallel with the one-way clutch may be brought into a complete engagement state in accordance with the vehicle speed and the driving state of the engine, instead of being in the half engagement state as in the above-mentioned example. .

The control device of the present invention is intended for an automatic transmission having a gear train other than the gear train shown in FIG. 4 or an automatic transmission having a hydraulic circuit other than the hydraulic circuit shown in FIG. You can Further, the present invention can be applied to a control device for an automatic transmission of a vehicle equipped with a motor or the like as a driving force source in addition to the engine.

Further, in the present invention, the torque capacity (engagement pressure) of the friction engagement device arranged in parallel with the one-way clutch.
Is not necessarily required to be feedback-controlled, and the engagement pressure of the friction engagement device may be controlled using data in which the vehicle speed, engine speed, throttle opening, etc. are mapped as parameters.

[0049]

As described above, according to the first aspect of the present invention, the friction engagement device in parallel with the one-way clutch is used when setting the shift speed on the low speed side achieved by the coast downshift. Since it is engaged, even if the one-way clutch is engaged by changing from the non-driving state to the driving state,
Since the friction engagement device is already engaged, the output torque is increased in accordance with the increase of the gear ratio, and therefore the increase of the output torque due to the engagement of the one-way clutch is small, and therefore the drive state is increased. It is possible to effectively prevent the shock caused by the change to the above and the one-way clutch is engaged.

Particularly, in the invention described in claim 2,
The torque capacity of the friction engagement device arranged in parallel with the one-way clutch is controlled to be lower than the capacity required to completely achieve the set low speed stage by engaging the friction engagement device. Therefore, it is possible to prevent the shock caused by engaging the friction engagement device and also effectively prevent the shock caused by the negative torque in the engine braking state.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining control contents executed by a control device of the present invention.

FIG. 2 is a diagram showing a range of an input rotation speed set by a friction engagement device in parallel with a one-way clutch.

FIG. 3 is a diagram schematically showing an overall control system according to the present invention.

FIG. 4 is a skeleton diagram showing an example of a gear train of an automatic transmission targeted by the present invention.

FIG. 5 is a diagram showing an engagement operation table of a friction engagement device for setting each shift speed in the automatic transmission.

FIG. 6 is a diagram showing an example of an array of range positions in a shift device.

FIG. 7 is a diagram schematically showing a hydraulic system that controls the hydraulic pressure of a fourth brake.

[Explanation of symbols]

 17 Electronic control unit for engine 18 Hydraulic control unit 19 Electronic control unit for automatic transmission A Automatic transmission B4 4th brake E Engine F2 2nd one-way clutch

Claims (2)

[Claims] 1. A vehicle that is downshifted to a shift speed set by engaging a one-way clutch arranged in parallel with a friction engagement device when the output of a driving force source is reduced to a non-driving state. In a shift control device for an automatic transmission for a vehicle, a non-driving state detecting means for detecting a non-driving state due to a reduction in output of a driving force source, and the one-way clutch by a change in a traveling state including a reduction in vehicle speed in the non-driving state. Downshift detecting means for detecting a downshift to the gear to be engaged, and when the downshift is detected by the downshift detecting means, the friction engagement arranged in parallel with the one-way clutch A shift control device for an automatic transmission for a vehicle, comprising: engagement control means for executing control for engaging the device. 2. The engagement control means includes means for controlling a torque capacity of the friction engagement device to a torque capacity lower than a torque capacity required to set a shift stage for engaging the one-way clutch. The shift control device for an automatic transmission for a vehicle according to claim 1, wherein: