JP2979448B2 - Control device for automatic transmission for vehicles - 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 for a vehicle having a function of preventing creep during stopping, and more particularly to an automatic transmission for performing a downshift when returning from creep prevention control to normal control. Machine control device.

[0002]

2. Description of the Related Art Conventionally, this kind of technology has been disclosed in
The thing described in -55456 gazette is known. This technology prevents the vehicle from retreating (hill hold control) by engaging the shift brake when performing neutral control (control for releasing the forward clutch to form a neutral state) to prevent creep when the vehicle is stopped. On the other hand, when returning from the neutral control to the normal control, the forward clutch is engaged when the braking operation of the foot brake is released, and the shift speed higher than the lowest speed (second speed) is engaged.
Then, when the accelerator is depressed, the shift brake is released to downshift to the first speed.

[0003]

In the case where the accelerator is depressed after the vehicle speed is increased after the foot brake is released on a downhill, the above-described conventional device requires the first gear to be formed. Immediately, the second speed is established according to the normal shift map.

For example, in the device having the shift map shown in FIG. 6, when the accelerator pedal is depressed in a state where the vehicle speed V3 is equal to or higher than V2 of the 1 → 2 shift-up line (point A in FIG. 6), When the neutral control is released, the vehicle is temporarily downshifted from the second gear to the first gear, but the vehicle speed is V2.
Since V3 is larger, the vehicle is immediately upshifted to the second speed.

When the accelerator pedal is depressed at a low throttle opening from a state where the increased vehicle speed is slightly lower than V2, the throttle opening is relatively low because the engine rotation is low (about 20). %), The torque is maximized, the vehicle is accelerated in the first speed stage due to the downshift, and the upshift to the second speed stage is immediately performed according to the normal shift line.

As described above, if the accelerator pedal is depressed after the vehicle speed has increased to some extent on a downhill, shift hunting from the second gear to the first gear and then to the second gear may occur. In addition to causing the driver to feel uncomfortable, and causing a shock due to unnecessary shifting.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is intended to control an automatic transmission for a vehicle which can eliminate a sense of incongruity due to unnecessary shifting and reduce a shift shock at the time of starting. By providing the device,
It is an object to solve the above problems.

[0008]

As shown in FIG. 1, the present invention includes a condition for releasing the accelerator pedal even when the shift range of the automatic transmission is set to the forward travel range. When the predetermined condition is satisfied, a neutral state is formed to prevent creep, and a brake that forms a predetermined high gear is engaged to prevent the vehicle from retreating. When other conditions except the release condition are not satisfied, the neutral state is released and the high speed stage is maintained, and when the accelerator pedal is further depressed in this state, the brake is released to downshift. the control apparatus, means for detecting the vehicle speed when the accelerator pedal is depressed, the vehicle speed when the該A click Serupedaru is depressed predetermined to By having a means for inhibiting the downshift when the above is obtained by solving the above problems.

[0009]

In the control device according to the present invention, when returning from the creep prevention control to the normal control, there are two stages of releasing.
First, when conditions other than the condition for releasing the accelerator pedal are not satisfied, the forward clutch C1 is engaged to release the neutral state, and the high speed is maintained in this state. Next, when the accelerator pedal is depressed in this state, the hill hold brake B1 is released to perform a downshift. However, if the vehicle speed has already exceeded the predetermined value when the accelerator pedal is released, no downshift is performed. Thereafter, the control returns to the shift control based on the normal map.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is an overall schematic diagram of an automatic transmission combined with an electronic fuel injection engine for an automobile. In this, the embodiment of the present invention is applied.

This automatic transmission has a torque converter 2
0, overdrive mechanism 40, three forward steps, one reverse step
And a stepped underdrive mechanism 60.

The torque converter section 20 includes a pump 2
1, a turbine 22, a stator 23, and a lock-up clutch 24. The output of the crankshaft 10 of the engine 1 is
Transmit to 0.

The overdrive mechanism 40 includes a sun gear 43, a ring gear 44, a planetary pinion 42,
And a set of planetary gear units consisting of
The rotational state of the planetary gear unit is controlled by a clutch C0, a brake B0, and a one-way clutch F0.

The underdrive mechanism 60 includes two sets of planetary gear units including a common sun gear 61, ring gears 62 and 63, planetary pinions 64 and 65, and carriers 66 and 67. The rotation state and the connection state with the overdrive mechanism 40 are controlled by clutches C1, C2, brakes B1 to B3, and one-way clutches F1, F2.

A computer 84 for controlling the automatic transmission includes a throttle sensor 80 for detecting a throttle opening for reflecting the load of the engine 1, a vehicle speed sensor (rotation speed sensor for the output shaft 70) 82 for detecting a vehicle speed, A sensor 99 for detecting the rotational speed of the clutch C0, a shift position switch 5 for outputting a shift position signal, a brake switch 6 for outputting a signal when a foot brake is depressed, a Ne sensor 7 for detecting the engine rotational speed Ne, an idle Contact state (when the accelerator pedal is depressed, OF
Signals for various controls such as an idle switch 8 for outputting F) and a water temperature switch 9 for detecting a cooling water temperature T of the engine are input.

The computer 84 uses the input signals from the respective sensors, switches and the like as parameters, and according to a preset throttle opening-vehicle speed shift point map, solenoid valves S1 and S2 in the hydraulic control circuit 106 to be described later.
, S3, S4, etc., are driven and controlled, and a shift control is performed by performing a combination of engagement of each clutch and brake as shown in FIG.

In the automatic transmission according to this embodiment,
A control valve for controlling the hydraulic pressure of the forward clutch (clutch C1) is newly provided, and when the accelerator pedal is released and the foot brake is depressed to substantially stop the vehicle, the shift range is increased. Even if it is in the forward drive range such as the drive range, the forward clutch is released or depressurized via the control valve, and a neutral state is automatically formed to prevent creep prevention, and
At the same time, the vehicle has a hill hold function for engaging a brake B1 capable of preventing the vehicle from moving backward on a slope or the like in order to prevent the vehicle from moving backward.

In this case, normally, as a hill hold brake, a brake B1 for forming an engine brake in a predetermined speed, for example, a second range (= S range) second speed, is used.
And the hill hold brake B1 is supplied with the engagement hydraulic pressure via valves (2-3 shift valve and 1-2 shift valve) which are opened when the second speed is achieved. . Therefore, when the creep reduction control is performed when the vehicle is stopped, the shift speed is normally maintained at the second speed.

From this state, when the condition for establishing the creep reduction control is not satisfied, the control returns to the normal control in a different procedure according to the condition for the failure. First, when the braking operation of the foot brake is released, a signal for engaging the forward clutch is output. At this stage, the previous second speed is maintained. Thereafter, when the accelerator is depressed, the shift brake is released, and the gear shifts down to the first speed.
However, this downshift may be stopped depending on the vehicle speed before the accelerator pedal is depressed.

Hereinafter, the hydraulic circuit in the apparatus of the embodiment will be described first, and then the control flow which is a characteristic part of the present invention will be described.

FIG. 4 shows a specific example of a hydraulic control device for executing creep reduction control (neutral control) and hill hold control.

In the figure, reference numeral 110 indicates a manual shift valve. This manual shift valve 1
10 has a hydraulic input port 114. The hydraulic pressure input port 114 is supplied with a line pressure PL sucked up by an oil pump 120 and regulated by a primary regulator valve 124 via an oil passage 126. The manual shift valve 110 has a spool 112 driven by a manual shift lever (not shown), and connects the hydraulic input port 114 to the D range port 116 when the manual shift range is the D range. When the manual shift range is the S range (two ranges), the hydraulic pressure input port 114 is connected to the S range port 118.

D range port 116 is connected to oil passages 300 and 30.
The S range port 118 is connected to the port 146 of the 2-3 shift valve 140 through the oil passage 304.
−3 is connected to the port 148 of the shift valve 140.

The 2-3 shift valve 140 is provided on the spool 1
42. When no hydraulic pressure is supplied to the port 144, the spool 142 is in the raised position shown in the right half of the drawing, and connects the port 146 to the port 150,
In addition, the port 148 communicates with the port 152. On the other hand, when hydraulic pressure is being supplied to the port 144, the port 144 is at the lowered position shown in the left half of the figure, and cuts off the communication between the port 146 and the port 150 and cuts off the communication between the port 148 and the port 152. , Port 152 communicate with the drain port 154.

The supply of control oil pressure to the port 144 is as follows:
This is performed in a known manner by a solenoid valve S1,
The oil pressure is supplied to the port 144 only when the speed stage or the overdrive stage (fourth speed stage) is achieved. Therefore, the spool 142 is at the raised position when the first speed or the second speed is achieved, and is at the lowered position when the third speed or the overdrive speed is achieved.

The solenoid valve S1 is of a normally closed type. When the solenoid valve S1 is "ON", the pressure is supplied to the port 144, and when the solenoid valve S1 is OFF, the pressure disappears. Therefore, when the first speed or the second speed is achieved, the solenoid valve S1
To “ON” to release the pressure, and when the third speed stage or the overdrive stage is achieved, the solenoid valve S1 is turned “OF”.
F "and supply pressure.

The port 150 is connected to a B1 control valve 18 for hill hold control described later by an oil passage 306.
0 port 186. Port 152 is
Oil passage 308, second coast modulator valve 16
0, port 1 of check valve 170 via oil passage 310
72.

The check valve 170 is connected to the inlet port 17.
In addition to the inlet port 174 and the outlet port 174, when an oil pressure is supplied to the inlet port 172 by the action of the check ball 178, the inlet port 174 is closed. When the hydraulic pressure is supplied to the inlet port 172, the inlet port 172 is closed. The inlet port 174 is connected to the port 188 of the B1 control valve 180 by an oil passage 312, and the outlet port 176 is connected to the
It is connected to the port 136 of the two-shift valve 130.

The 1-2 shift valve 130 has a spool 13
2 When hydraulic pressure is not supplied to the port 134, the spool 132 is in the raised position shown in the left half of the figure and communicates the ports 136 and 138. On the other hand, when hydraulic pressure is supplied to the port 134, the right half of the figure is The port 136 is disconnected from the drain port 139 by shutting off the ports 136 and 138 at the lower position shown in FIG.

The port 138 is connected to the brake B1 by an oil passage 316.

The port 134 has a solenoid valve S2
Due to the operation described above, the hydraulic pressure is supplied only when the first speed is achieved, whereby the spool 132 is set to the raised position when the second speed, the third speed, or the overdrive speed is achieved, and when the first speed is achieved. Only the lowered position is set.

The solenoid valve S2 is also a normally closed type. When "ON", pressure is supplied to the port 134, and when "OFF", no pressure is applied.

The relationship between the operation signals to the solenoid valves S1 and S2 and the shift speed is as shown in the table below.

[0035]

The B1 control valve 180 provided for hill hold control includes a spool 182 and a plug 18
And 4. When the spool 182 is in the raised position shown in the right half of the figure, the ports 186 and 188 communicate with each other, and the ports 190 and 192 are shut off so that the port 1
92 is connected to the drain port 198. On the other hand, when in the lowered position shown in the left half of the figure, the port 186 is closed, the port 188 communicates with the drain port 187, and the ports 190 and 192 communicate.

The port 190 is connected to the oil passages 314 and 300
Is connected to the D range port 116 of the manual shift valve 110, and the port 192 is connected by an oil passage 316 to the port 208 of the C1 control valve 200 provided for neutral control (for creep reduction control).

The spool 182 of the B1 control valve 180 is driven by the hydraulic pressure applied to the ports 194 and 196, and when at least one of the ports 194 and 196 is supplied with the signal hydraulic pressure Ps equal to or more than the predetermined value Psset, the left half position That is, the hill hold control is released. When the signal oil pressure Ps equal to or greater than the predetermined value Psset is not supplied to any of the ports 194 and 196, the port is located at the right half position, that is, the hill hold control position. Port 194 is oil passage 318
As a result, the oil pressure is connected to the oil passage 320 to supply the signal oil pressure Ps of the oil passage 320.

The solenoid valve S3 provided as the main control means of the C1 control valve 200 for neutral control and the B1 control valve 180 for hill hold control has a function corresponding to the duty ratio D of the pulse signal applied to its electromagnetic coil. , A signal pressure Ps corresponding to the duty ratio D is generated in the oil passage 320. The solenoid valve S3 is constituted by a so-called normally closed solenoid valve, whereby the signal oil pressure Ps of the oil passage 320 decreases as the duty ratio D applied to the electromagnetic coil increases. Oil passage 32
0 is the throttle 280, the oil passage 322, the modulator valve 25
0, which is connected to the oil passage 126 via the oil passage 324, whereby the oil pressure 322 regulated to a predetermined constant pressure by the modulator valve 250 is supplied to the oil passage 322.

The oil passage 320 is connected to a port 194 of the B1 control valve 180 by an oil passage 318, and is connected to a port 210 of the C1 control valve 200 via an oil passage 326 and a throttle 282.

The C1 control valve 200 has a spool 202 and two plugs 204 and 206.
Spool 202 is connected to oil passage 3 by oil passages 328 and 314.
00 and a port 21 to which the line pressure PL is supplied.
By controlling the degree of communication with the second drain port 216, the hydraulic pressure at the outlet port 214 is adjusted. The pressure adjustment value is increased in accordance with the urging force applied to the spool 202 by the compression coil spring 218 and the pressing force applied directly to the spool 202 by the plugs 204 and 206. Exit port 214
Is connected to the clutch C1 via a C1 relay valve 270 provided for fail-safe of the C1 control valve 200.

That is, a C1 relay valve 270 is arranged between the port 214 of the C1 control valve 200 and the clutch C1. The port 214 of the C1 control valve 200 and the C1 relay valve 270
Port 272 is connected by an oil passage 330. The clutch C1 and the port 276 of the C1 relay valve 270 are connected by an oil passage 340. Further, a D range line pressure PL generated at the D range port 116 of the manual valve 110 is guided to a port 274 of the C1 relay valve 270 by an oil passage 336.

In the middle of the oil passage 340, a throttle 284
Is provided. Also, the oil passage 340 and the oil passage 300
It is connected via a check valve 260. The check valve 260 is configured to allow only the flow of oil from the oil passage 340 to the oil passage 300, that is, the drain flow of the oil.

The hydraulic control device of the present embodiment is provided with another solenoid valve S4. The solenoid valve S4 controls the oil pressure of the oil passage 410 to a high pressure or a low pressure by being turned on / off. The oil passage 410 is connected via a throttle 411 and an oil passage 412 to an oil passage 126 that is adjusted to the line pressure PL by the primary regulator valve 124.

The C1 relay valve 270 has two control signal input (pilot) ports 277 and 278 for switching control of its own spool position in the same direction, and at least one of the ports 277 and 278. , 27
8, when the oil pressure higher than the set pressure is introduced, it is located at the right half position in FIG.
To communicate with Also, when the pressures of both ports 277 and 278 are both lower than the set pressure, the port is located at the left half position in FIG.

The one control signal input port 277
Is connected to the oil passage 320 via an oil passage 334, and is connected to a port 277 through a valve C3 controlled by a solenoid valve S3.
1 A pressure Ps for control valve control is introduced. Also, the other control signal input port 27
Numeral 8 is connected to an oil passage 410 via an oil passage 413, and a hydraulic pressure controlled by a solenoid valve S4 is introduced into a port 278.

The control signal input port 196 of the B1 control valve 180 is connected via an oil passage 414 to an oil passage 410 whose pressure is controlled by a solenoid valve S4.

Next, the operation of the hydraulic control device having the above configuration will be described.

When the manual shift range is set to "D range", the solenoid valve S2 is set to "OFF",
When the first speed is established by turning ON the solenoid valve S1, the 1-2 shift valve 1
30 is in the lowered position, and the spool 142 of the 2-3 shift valve 140 is in the raised position.

The creep reduction control and the hill hold control have not been started yet, and the solenoid valve S3 is turned off.
While the signal is being given, the signal oil pressure Ps of the oil passage 320
Is set to the same oil pressure as the output oil pressure Pm of the modulator valve 250, and this oil pressure is set to the B1 control valve 180.
Port 194 and the port 210 of the C1 control valve 200. Therefore, at this time, B
1 The spool 180 of the control valve 180 is located at the left position, that is, the hill hold control release position, whereby the port 186 is closed and the hill hold control output port 188 is connected to the drain port 187.

Further, since the port 190 communicates with the port 192, the line pressure PL from the oil passages 300 and 314 is increased.
Enters the port 208 of the C1 control valve 200 through the oil passage 316, and the C1 control valve 2
00 is located at the left position, that is, the normal mode position, by the action of the line pressure PL supplied to the port 208 in addition to the signal oil pressure Ps applied to the port 210.

As a result, since the drain port 216 is completely closed, the line pressure PL applied to the port 212 is not reduced, but is directly introduced into the clutch C1 from the port 214 via the oil passage 330. Therefore, at this time, the clutch C1 is completely engaged, and the first speed is achieved.

Since the port 186 of the B1 control valve 180 is closed, the port 188 is drain-connected, and the port 13 of the 1-2 shift valve 130 is
6 is also closed and port 138 is drain connected,
No hydraulic pressure is supplied to the brake B1 and the brake B1
Are maintained in a released state.

Next, when the manual shift range is set to the "D range", the throttle opening of the engine 1 is returned to the idle opening position (idle contact ON), and the vehicle speed is close to zero. When the pressure falls below a predetermined value, control commands are issued to the solenoid valves S1 to S4 to execute creep reduction control and hill hold control.

That is, a pulse signal is given to the solenoid valve S3, and its duty ratio D is increased with the passage of time. In response to the increase in the duty ratio D, the signal oil pressure Ps of the oil passage 320 gradually decreases with the passage of time, and when the signal oil pressure Ps decreases to a predetermined value Psset, the spool 182 of the B1 control valve 180 moves to the position shown in FIG. To the right side (hill hold control side), and the communication port of port 188 is connected to drain port 187.
To port 186. Further, the communication port of the port 192 is switched from the port 190 to the drain port 198.

Therefore, since the line pressure PL is not supplied to the port 208, the pressure adjustment value of the C1 control valve 200, that is, the engagement pressure of the clutch C1 is set by the signal oil pressure Ps applied to the port 210, and the signal oil pressure Ps
The drain port 216 is opened with the decrease of. As a result, the engagement pressure supplied from the port 214 to the clutch C1 decreases, and this causes the clutch C1 to slip. Thus, the automatic transmission is in the same state as in the neutral state, and the occurrence of creep is prevented at the same time as the idle vibration is reduced. That is, creep reduction control is executed.

At this time, both the solenoid valves S1 and S2 are turned "ON" in order to achieve the second speed stage.
Operated. At this time, since the ports 186 and 188 of the B1 control valve 180 communicate with each other as described above, when the solenoid valve S1 is turned "ON", the spool 142 of the 2-3 shift valve 140 is raised, that is, the first speed. The manual shift valve 11 is operated by operating the shift position to achieve the second speed or the second speed.
0, the line pressure PL of the D range port 116 is
0, 302, port 146 of 2-3 shift valve 140
And 150, oil passage 306, B1 control valve 18
0 through ports 186 and 188, an oil passage 312, a check valve 170, and an oil passage 314.
It reaches port 136 at 0.

Then, the solenoid valve S2 is turned "ON".
As a result, the spool 132 of the 1-2 shift valve 130 is operated to the raised position, that is, the switching position for achieving the second speed, the third speed, or the overdrive stage (fourth speed). Line pressure PL reached
Is supplied from the port 138 to the brake B1 via the oil passage 316, the brake B1 is engaged, and the sun gear 61 (FIG.
Reference) is fixed. Therefore, the sun gear 6
1 and the carrier 67 is prevented from rotating backward by the action of the one-way clutch F2, so that the planetary pinion 65 is prevented from rotating backward, whereby the ring gear 6 is prevented from rotating.
3 is prevented, the output shaft 70 is prevented from rotating in the reverse direction of the vehicle, and so-called hill hold control is executed.

That is, even when the manual shift range is in the "D range", the same shift speed as the second speed in the "S range" is achieved by the engagement of the brake B1. Thus, the vehicle is prevented from moving backward.

Next, the control flow, which is a characteristic part of the apparatus of this embodiment, will be described with reference to the flowchart of FIG. The meanings of the flags used in this flowchart are as follows.

F1 = Neutral control start (clutch hydraulic sweep down control) to flag indicating that the clutch is fully engaged by return F2 = To achieve the second speed state to perform hill hold control Flag indicating that solenoid valve S2 is ON

FIG. 5 shows the contents of the creep reduction (= prevention) control. This routine is repeatedly executed periodically, and when this routine is started, steps 600 to 600 are executed.
At 605, a condition for establishing the creep prevention control is determined. The conditions include the following.

The shift range is the drive range (Step 600) The idle contact signal is on (Step 601) The foot brake signal is on (Step 602) The vehicle speed V is equal to or less than a predetermined value V0 close to zero (Step 603) The engine speed Ne is predetermined Value Ne or less (Step 604) The engine cooling water temperature is equal to or more than a predetermined value T1 (Step 60).
5)

When all of these conditions are satisfied, anti-creep control is executed. here,,,
The conditions (1) and (2) correspond to conditions for substantially realizing the creep prevention control, and the conditions (2) and (3) correspond to conditions detected for confirmation from the viewpoint of fail-safe.

If all of these conditions are satisfied, step 60
Proceed to 6 to execute neutral control. Then, in step 607, "1" is set to a flag F1 indicating that the neutral control has been started, and in step 608, the solenoid valve S is set to engage the hill hold brake.
Then, an ON signal is output to step 2 and a flag F2 indicating that the hill is being held is set to "1" at step 609.

When the foot brake is released from the neutral control (creep reduction control) state, the determination in step 602 is NO, and the routine proceeds to step 617.
Here, since the flag F1 = 1, the routine proceeds to step 620, where it is determined whether the clutch C1 is completely engaged. If not, the routine proceeds to step 621, where the clutch C1 is engaged.
, The duty ratio for adjusting the clutch oil pressure is reduced.

This loop is repeated, and when the clutch C1 is completely engaged, Steps 620 to 619 are performed.
Then, it is determined whether or not the vehicle speed ≦ V1 (where V1 is the vehicle speed of the 2 → 1 downshift in the shift map of FIG. 6). If the vehicle speed is equal to or lower than V1, the process proceeds to steps 614 and 615 and the flag F1 is determined. Is set to "0".

If the vehicle is creeping with the foot brake released, the process proceeds from step 600 to step 602, and further proceeds from step 617 to step 618 because the flag F1 = 0. Here, since the flag F2 = 1, the routine proceeds to step 619, where the vehicle speed is determined as described above. If the place where creeping is traveling is a downhill road, acceleration is performed, and if the vehicle speed becomes greater than V1, the determination in step 619 is N.
It becomes O, and the routine proceeds to step 613, where the flag F2 is set to "0"
Is set.

When the flag F1 = 0 and the flag F2 = 0, the shift processing along the normal shift line is performed.
Thereafter, even if the idle contact changes from OFF to ON, the process proceeds from step 610 to step 613, and the turning off of the solenoid valve S2 in step 612 is not executed. That is,
No downshift from the second gear to the first gear is performed.

If it is determined that the shift range is not the drive range, the process proceeds to step 616 or 623. When the shift range is not the drive range, the creep prevention control is not executed. Therefore, when the range is the 2 range or the L range, the process proceeds to step 617.

On the other hand, when it is determined that the shift range is not the drive range, the two range, or the L range,
Proceeding to step 623, the clutch is fully opened, and in step 624, the flag F1 is set to "0".
In step 6, "0" is set in the flag F2.

As described above, when returning from the neutral control to the normal control, if the vehicle speed at the time when the accelerator pedal is depressed (including immediately before and immediately after) is higher than the 2 → 1 shift line, the unnecessary first speed Since the downshift to the gear is not performed, the hunting of the shift range is eliminated, and the uncomfortable feeling of the occupant and the shift shock are reduced.

[0073]

As described above, according to the control apparatus for a vehicle automatic transmission of the present invention, when returning from the neutral control to the normal control, the accelerator pedal is depressed after the vehicle speed increases on a downhill road or the like. In this case, unnecessary downshifts are not performed, and the vehicle can travel while maintaining the high speed stage. Therefore, unnecessary shift hunting is eliminated, the discomfort of the occupant is eliminated, and the shift shock is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is a schematic configuration diagram of an entire system including an automatic transmission to which an embodiment of the present invention is applied;

FIG. 3 is a diagram showing an engaged and disengaged state of a friction engagement device at each shift speed in the automatic transmission.

FIG. 4 is a diagram showing a structure of a hydraulic control device of the automatic transmission according to the embodiment.

FIG. 5 is a flowchart showing a part of control contents in the embodiment.

FIG. 6 is a diagram showing an example of a shift map of the automatic transmission.

[Explanation of symbols]

 C1: forward clutch, B1: brake, S1, S2: solenoid valve, 5: shift position switch, 8: idle switch, 130: 1-2 shift valve, 150: 2-3 shift valve, 200: C1 control valve.

Continuation of front page (56) References JP-A-61-55456 (JP, A) JP-A-54-81461 (JP, A) JP-A-63-72950 (JP, A) JP-A-1-164846 (JP) JP-A-60-81558 (JP, A) JP-A-58-225253 (JP, A) JP-A-61-214757 (JP, A) JP-A-3-54034 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] 1. Even when the shift range of the automatic transmission is set to the forward traveling range, a neutral state is formed to prevent creep when a predetermined condition including a condition for releasing the accelerator pedal is satisfied. At the same time, the brake that forms a predetermined high gear is engaged to prevent the vehicle from retreating. On the other hand, when any of the predetermined conditions other than the accelerator pedal release condition is not satisfied, the neutral state is set. In the control device of the automatic transmission that releases the brake and downshifts when the accelerator pedal is further depressed in this state while maintaining the high-speed gear, the accelerator pedal is depressed when the accelerator pedal is depressed. Bei means for detecting a vehicle speed, and means for prohibiting the downshift when the predetermined value or more speed when該A click Serupedaru is depressed, the Control apparatus for a vehicular automatic transmission, characterized in that the.