JP3116514B2 - Control device for automatic transmission for vehicles - Google Patents

Abstract

PURPOSE:To prevent a backward movement of a vehicle in a slope by executing the engagement of a friction engaging element for forward movement and the ineffective operation of a friction engaging element for backward movement, when a specific condition to excute a specific transmission control is made ineffective by a reason other than the accelerator. CONSTITUTION:When the shift range of an automatic transmission is in the forward running condition, and a specific condition including an accelerator OFF condition is made effective, a friction engeging element B to accomplish the second speed range, and a friction engaging element C to prevent the backward movement of the vehicle are operated, while a friction engeging element A to realize a forward running is slided, in the automatic transmission. In such an automatic transmission, when it is detected that the above specific condition is made ineffective by a cause other than the accelerator while the accelerator is being OFF, the friction engeging element A is engaged, and the friction engeging element C is made inoperative. When the the accelerator ON is detected After the above condition is made ineffective by the cause other than the accelerator, the friction engaging element B is controlled to be inoperatve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an automatic transmission for a vehicle,
In particular, the present invention relates to a control device related to creep prevention.

[0002]

2. Description of the Related Art An automatic transmission for a vehicle generally includes a hydraulic torque converter that receives rotational power from an engine, and a gear transmission that receives rotational power from the hydraulic torque converter. Is switched according to a predetermined shift pattern in accordance with the vehicle speed and the amount of depression of the accelerator pedal.

As is well known, a shift range such as a drive range, a neutral range, a parking range, etc. is set as a manual shift range of an automatic transmission, and this manual shift range is set as a drive range. In such a case, so-called creep occurs in which the vehicle moves forward little by little. This is because when the drive range is set, the gear transmission is set to the first speed state and the engine is rotating at the idle speed, so that a small amount of torque is transmitted to the wheel side via the torque converter. That's why.

The creep phenomenon can be eliminated by setting the manual shift range to the neutral range, but the manual shift range is maintained in the drive range during running, particularly when starting and stopping are performed frequently. It is common practice to suppress this creep phenomenon with a foot brake while keeping it.

[0005] In view of the above, conventionally, the shift range is set to the forward traveling range, the accelerator pedal is released,
When the foot brake is depressed and the vehicle speed is detected to be substantially zero, the forward clutch (the frictional engagement element that engages when executing forward running) of the gear transmission is slid to automatically perform the operation. There has been proposed a control in which a neutral state is formed in order to prevent creep.

Further, there is also a technique in which a hill hold brake (a frictional engagement element for realizing reverse prevention) is engaged in order to reliably prevent the vehicle from moving backward when the creep prevention control is executed. It has been proposed (Japanese Unexamined Patent Publication No.
-55456).

Further, in order to effectively realize the effect of reducing the creep force, a second brake (a friction engagement element for setting the automatic transmission to a high speed (second speed) other than the first speed). ) Has also been devised (Japanese Patent Publication No. Sho 6).
0-35816).

[0008] As described above, when the creep prevention control is executed, if another control is executed in a complex manner, for example, in what sequence when returning from the creep prevention control, The problem is somehow.

According to the above-mentioned JP-A-61-55456, when returning from the creep prevention control, the control of the forward clutch and the hill hold brake is performed by first shifting the hydraulic pressure of the forward clutch forward when the foot brake is released. Increase (engage) to the step achievement value,
At this time, a sequence has been proposed in which the hill hold brake is kept engaged and the hill hold brake is released the next time the accelerator pedal is depressed. By adopting such a sequence, the creep is reduced. It is described that even if the foot brake is released during the prevention control, the hill hold brake is operated, so that the vehicle is prevented from retreating on a slope.

[0010]

However, with regard to the conventional control for simultaneously handling the three frictional engagement elements of the forward clutch, the hill hold brake, and the second brake, there is disclosed a control that particularly discloses a rational sequence for its return. The fact is that there is no such thing.

For example, based on the above-mentioned conventional example, when the control of the second brake is added, the forward clutch is first engaged with the detection of the brake off, and then the hill hold brake is detected with the detection of the accelerator on. Is released, and a sequence of releasing the second brake is considered here.

However, when such a sequence is taken, particularly when the depression amount of the accelerator pedal is small, the shock of the downshift from the second gear to the first gear is very large. The problem that it is done occurs.

On the other hand, if the engagement of the forward clutch and the release of the second brake are performed simultaneously with the detection of the brake off, the release of creep and the downshift overlap, so that the Can be very large.

The present invention has been made in view of such a conventional problem, and in executing the creep prevention control, the control for simultaneously operating the hill hold brake and the second brake is executed in parallel. In case,
The above-described problem has not been solved by rationally defining a sequence for such a return and enabling a smooth return without causing a problem and without generating a large shock.

[0015]

The first aspect of the present invention is shown in FIG.
As shown in (A), when the shift range of the automatic transmission is set to the forward travel range and a predetermined condition including an accelerator-off condition is satisfied, a friction engagement element that realizes forward travel is provided. Automatic transmission for a vehicle configured to execute a specific control of causing a friction engagement element that achieves the second speed stage to act and a friction engagement element that prevents the vehicle from retreating while sliding the vehicle. in the control device of the machine, while the predetermined condition is the accelerator is turned off, blanking
Means for detecting that the rake operation has failed, and friction for preventing engagement of the friction engagement element for realizing the forward running and retreat of the vehicle when the predetermined condition has failed due to the brake operation . Means for performing only the non-operational operation of the engagement element, means for detecting that the accelerator is turned on after the predetermined condition is not satisfied by the brake operation , Means for disabling the friction engagement element for achieving the step, thereby solving the above problem.

As shown in FIG. 1B, when the shift range of the automatic transmission is set to the forward traveling range, the second invention includes a predetermined condition including an accelerator-off condition. Is established, the friction engagement element that achieves the forward running is slid, the friction engagement element that achieves the second speed is operated, and the friction engagement element that prevents the vehicle from moving backward is operated. Means for detecting that the predetermined condition is not satisfied by a brake operation while the accelerator is off, in the control device for a vehicle automatic transmission configured to execute the control of When the predetermined condition is not satisfied by the brake operation , only the engagement of the friction engagement element for realizing the forward running and the non-operation of the friction engagement element for preventing the vehicle from moving backward are determined. Means to perform and brake After the predetermined condition is not satisfied by the operation , at least one of the accelerator opening and the rate of change thereof is set.
And a friction engagement element that achieves the second speed when it is detected that at least one of the accelerator opening and the rate of change has exceeded a predetermined value. And means for disabling,
Similarly, the above-mentioned problem has been solved.

[0017]

According to the present invention, when the blanking Rekio off thus for performing the particular control "predetermined condition" not to be established, first, where the frictional engagement element for realizing the forward travel ( Forward clutch)
At this stage, the non-operation (release) of the friction engagement element (hill hold brake) for preventing the vehicle from moving backward is executed.

As a result, the function of completely preventing the vehicle from retreating is lost, but since the forward clutch is engaged, the vehicle will creep in the second speed state, and if the vehicle is running on a slight slope, the vehicle will not move. There is no retreat. Further, if the vehicle is on a flat ground, the vehicle starts to move forward little by little by a slight creep, so that it is possible to easily execute a slight advance only by a brake operation, for example, during traffic congestion.

Further, by simultaneously performing the control of the forward clutch and the hill hold brake in this manner, the reverse is always prevented when the anti-creep control is executed, and the reverse is prevented when the anti-creep control is not executed. No control will be performed. This is reasonable in the following respects.

That is, in addition to the brake-on operation and the accelerator-off operation, the creep prevention control is generally accompanied by other conditions such as, for example, the engine cooling water temperature being higher than a predetermined value. If there is a time lag between the case and the release of the hill hold brake, even if the brake is turned on and off in the same way on the same slope,
Depending on whether the environment at that time happens to satisfy the condition for starting the creep prevention control, there are cases where the vehicle moves backward and cases where the vehicle does not move backward.

In the case of the present invention, when the creep prevention control is released by turning off the brake, the hill hold brake is not always activated at the same time, so that the same behavior is always performed on the same slope when the brake is turned on and off. And the driver does not feel uncomfortable.

In addition, in the first aspect of the present invention, the friction engagement element that achieves the high-speed stage together with the detection of the accelerator-on is deactivated. As a result, the downshift from the second speed to the first speed is always performed coincident with when the accelerator pedal is depressed. For example, when the brake is turned off, the three friction engagement devices are engaged at once. Alternatively, it is possible to reduce the shock at the time of return as compared with the case of releasing.

Further, the second invention is based on the technical idea of the first invention, and is based on the condition that the friction engagement element for achieving the high-speed gear is inactive as well as the accelerator-on condition. The time when at least one of the opening degree and the change rate is equal to or more than a predetermined value is detected. As a result, even when the accelerator is turned on, when the accelerator opening or the rate of change thereof is small, the high gear is maintained, and therefore, no shock due to the execution of the downshift occurs.

On the other hand, when the accelerator opening or the rate of change thereof is equal to or greater than a predetermined value, that is, when the driver operates the accelerator pedal for a strong driving force, a downshift is performed at the same time. In this case, however, the downshift shock is masked by the change in the engine torque due to the rapid opening of the accelerator, and the driver does not feel particularly uncomfortable.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 shows an overall outline of an automatic transmission for a vehicle to which the embodiment of the present invention is applied.

This automatic transmission has a torque converter 20
, An overdrive mechanism 40, and an underdrive mechanism 60 having three forward stages and one reverse stage.

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 lock-up clutch 24 is engaged when conditions are satisfied, and connects the pump 21 and the turbine 22. As a result, the fuel consumption effect is improved.

The overdrive mechanism includes a set of planetary gear units including a sun gear 43, a ring gear 44, a planetary pinion 42, and a carrier 41. The rotational state of the planetary gear unit is determined by a clutch C0 and a brake B0.
, And is controlled by 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 are controlled by clutches C1, C2, brakes B1 to B3, and one-way clutches F1, F2.

Since the specific configuration of the transmission section of this automatic transmission is well known per se, only the skeleton is shown in FIG. 2 and detailed description is omitted.

This automatic transmission includes the above-described transmission unit and the computer 84. The computer 84 has a throttle sensor 80 with an idle switch for detecting the throttle opening .theta. For reflecting the load of the engine 1, a vehicle speed sensor (rotation speed sensor for the output shaft 70) 82 for detecting the vehicle speed N0, and a foot brake on. A foot brake switch 90 for detecting that the engine speed has been set, an engine speed sensor 92 for detecting the engine speed,
Signals for various controls such as an engine coolant temperature sensor 94 and a C0 speed sensor 99 for detecting the speed of rotation of the clutch C0 are input.

The rotational speed of the clutch C0 is the same as the rotational speed of the output shaft of the turbine 22, that is, the torque converter 20, from the first speed to the third speed. Therefore, it can be sufficiently used as the output shaft rotation speed (turbine rotation speed) Nt of the torque converter unit 20 when executing the creep control.

The computer 84 controls the hydraulic control circuit 8 according to a preset throttle opening-vehicle speed shift point map.
The solenoid valve in 6 is driven and controlled to perform a shift by performing a combination of engagement of each clutch, brake and the like as shown in FIG.

In this automatic transmission, the clutch C1 corresponds to a forward clutch that is slipped during creep control. The brake B1 corresponds to a hill hold brake (backward brake), and the brake B2 corresponds to a second brake for achieving the second speed (high speed).

As is apparent from FIG. 3, when the shift range is in the forward running range, the forward clutch C
1 is in the engaged state, and the vehicle can travel forward.

However, when the throttle opening θ is zero (or the idle contact is on), the brake pedal is depressed, and the vehicle speed is zero (including substantially zero), the engagement pressure of the clutch C1 is reduced. The automatic transmission is shifted to the neutral state by the reduction. At the same time, the hill hold brake B1 is used to prevent the vehicle from moving backward, that is, to operate the so-called hill hold function.
Is engaged, and the second brake B2 is also engaged at the same time so that the automatic transmission is set to the second speed state and the anti-creep control (forward clutch feedback control) is performed more smoothly.

Next, a hydraulic control circuit for executing the above control will be described with reference to FIG.

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). When the manual shift range is in the D range, the hydraulic input port 114 is connected to the D range port 116. When the manual shift range is the S range, 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 connected to 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 the hydraulic pressure is supplied to the port 144, the port 144 is at the lower position shown in the left half of the figure, and the communication between the port 146 and the port 150 is cut off. Cut off,
The port 152 communicates with the drain port 154.

The supply of hydraulic pressure to the port 144 is performed by a solenoid valve S1 in a known manner, and the hydraulic pressure is supplied to the port 144 only when the third speed stage or the overdrive stage is achieved. Therefore,
The spool 142 is in the raised position when the first speed or the second speed is achieved, and is in the lowered position when the third speed or the overdrive speed is achieved.

The port 150 is connected to a port 186 of the B1 control valve 180 by an oil passage 306. The port 152 is connected to the port 172 of the check valve 170 via the oil passage 308, the second coast modulator valve 160, and the oil passage 310.

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
1 The outlet port 176 is connected to the port 188 of the control valve 180, and the outlet port 176 is connected to the port 136 of the 1-2 shift valve 130 by an oil passage 314.

The 1-2 shift valve 130 is connected to the 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 hydraulic pressure is supplied to the port 134 only when the first speed is achieved by the action of the solenoid valve S2, so that the spool 132 is raised when the second speed, the third speed or the overdrive speed is achieved. And the lowered position only when the first gear is attained.

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

A second brake B2 is connected to the port 531 via an oil passage 501, and when the 1-2 shift valve 130 is in the first speed (the spool 132).
Is in the lowered position) and the spool 13
When the second gear 2 is in the ascending position (when the second gear, the third gear, or the overdrive gear is achieved), the line pressure supplied to the port 530 via the oil passage 500 is supplied to the second brake B2. It has become.

The B1 control valve 180 has a spool 182 and a plug 184. When the spool 182 is in the raised position shown in the right half of FIG.
86 and 188 and ports 190 and 192
And the port 192 is communicated with 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 and the port 18 is closed.
8 to the drain port 187 and the port 190
And 192 are communicated.

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

The spool 182 is connected to the ports 194 and 196
Driven by hydraulic pressure applied to ports 194 and 1
96, a signal oil pressure P equal to or more than a predetermined value Psset.
When s is supplied, it is located at the left half position, that is, the hill hold control release position. Also, port 194
And 196, the signal oil pressure Ps equal to or more than the predetermined value Psset
Is not supplied, the position is at the right half position, that is, the hill hold control position.

Port 194 is connected to oil passage 3 by oil passage 318.
20 and is supplied with the signal oil pressure Ps of the oil passage 320. The port 196 is supplied with throttle oil pressure or servo oil pressure (engagement pressure) for the clutch C1 through an oil passage (not shown).

The solenoid valve 240 operates according to the duty ratio D of the pulse signal applied to the electromagnetic coil.
A signal pressure Ps corresponding to the duty ratio D is generated in the oil passage 320. The solenoid valve 240 is constituted by a so-called normally-closed solenoid valve.
Decreases as the duty ratio D applied to the electromagnetic coil increases.

The oil passage 320 is connected to the oil passage 126 through the throttle 280, the oil passage 322, the modulator valve 250, and the oil passage 324 so as to be supplied with the original oil pressure.
A modulation oil pressure Pm adjusted to a predetermined constant pressure by a modulator valve 250 is supplied to 22.

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 increases 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 21
Reference numeral 4 is connected to the clutch C1 via the throttle 284 and the oil passage 330.

The oil passage 328 and the oil passage 330 are
14. Connected by check valve 260.
The check valve 260 is moved from the oil passage 330 to the oil passage 328.
To the oil flow, that is, only the oil drain flow.

When the manual shift range is set to the D range and the first speed is established, the spool 132 of the 1-2 shift valve 130 is at the lowered position,
The spool 142 of the 2-3 shift valve 140 is in the raised position.

While the creep reduction control and the hill hold control have not been started yet and the OFF signal is given to the solenoid valve 240, 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.

Accordingly, at this time, the spool 180 of the B1 control valve 180 is located at the left position, that is, the hill hold control start position, whereby the port 186 is closed and the 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 side 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 forward clutch C1 from the port 214 via the oil passage 330. Therefore, at this time, the forward clutch C1 is fully engaged, and the first speed is achieved.

Further, since the port 186 of the B1 control valve 180 is closed, the port 188 is drain-connected.
6 is also closed and port 138 is drain connected,
No hydraulic pressure is supplied to the hill hold brake B1,
Hill hold brake B1 maintains the released state. Further, the second brake B2 is also released since the port 531 is connected to the drain port.

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), the foot brake 90 is depressed, and the vehicle speed is reduced to zero. When a predetermined value close to or below is reached, a pulse signal is supplied to the solenoid valve 240 in order to perform creep reduction control and hill hold control, and the duty ratio D is increased with time.

As the duty ratio D increases, the oil passage 3
The signal pressure Ps at 20 gradually decreases over time,
When the signal oil pressure Ps decreases to a predetermined value Psset, B
1 The spool 182 of the control valve 180 switches to the right position in the figure, and the communication port of the port 188 switches from the drain port 187 to the port 186. Also, the communication port of the port 192 is changed from the port 190 to the drain port 1.
Switch to 98.

Accordingly, 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 forward clutch C1
The drain pressure 216 is set by the signal oil pressure Ps applied to the valve 10, and the drain port 216 is opened as the signal oil pressure Ps decreases.

As a result, the engagement pressure supplied from the port 214 to the forward clutch C1 decreases, and this causes the forward 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.

On the other hand, at this time, since the ports 186 and 188 of the B1 control valve 180 communicate with each other as described above, the spool 142 of the 2-3 shift valve 140 is in the raised position, that is, the first speed or the second speed. In the switching position to achieve the step, the manual shift valve 11
If the line pressure PL of the D range port 116 of 0 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.

Therefore, at this time, the 1-2 shift valve 1
30 if the spool 132 is in the raised position,
Line, the line pressure PL at port 136 is at port 1
The hill hold brake B1 is supplied to the hill hold brake B1 via the oil passage 316, and the hill hold brake B1 is engaged to fix the sun gear. Therefore, the rotation of each of the front sun gear and the rear sun gear is prevented, and the rotation of the output shaft is prevented from rotating in the backward direction of the vehicle by the action of the one-way clutch 92, so-called hill hold control is executed.

At this time, ie, the 1-2 shift valve 1
30 is in the raised position, the line pressure PL of the port 530 increases from the port 531 to the oil passage 501.
Is supplied to the second brake B2, and the second brake B2 is engaged. Therefore, the gear position of the automatic transmission is in the second speed state, and the torque handled by the forward clutch C1 is reduced, so that creep reduction control can be performed easily and smoothly.

That is, in this embodiment, the signal oil pressure Ps
However, according to a control flow as shown below, the clutch C0
The feedback control is performed so that the rotation speed (= turbine rotation speed Nt) becomes the target value (around Ps set),
The amount of slip of the forward clutch C1 is finely adjusted. Therefore, by setting the automatic transmission to the second speed, the torque handled by the forward clutch 1 is reduced, so that the fine adjustment (feedback control) of the slip amount can be easily performed. .

FIG. 5 shows a control flow executed in the above embodiment.

In FIG. 5, steps 401 to 406 correspond to steps for judging the conditions for establishing the creep prevention control.

That is, in this embodiment, the shift range is the drive range (step 401), the idle contact signal is on (step 402), the foot brake signal is on (step 403), and the vehicle speed V is less than a predetermined value V0 close to zero. (Step 40
4) The engine speed Ne is equal to or less than a predetermined value Neo (step 4).
05), the engine cooling water temperature T is equal to or higher than a predetermined value T0 (step 40).
6) When all of the conditions are satisfied, the creep prevention control is executed.

Here, the conditions (1) to (4) correspond to the substantial conditions for the anti-creep control, and the conditions (3) correspond to the conditions detected for confirmation from the viewpoint of fail-safe.

When all of these conditions are satisfied, the routine proceeds to step 407, where the forward clutch C1 is released, a neutral state is formed, and a state in which creep is prevented is established.

More specifically, a difference obtained by subtracting the actual turbine rotation speed from the target turbine rotation speed is calculated, and a duty ratio command value for solenoid valve 240 is output so that the difference is maintained at a predetermined value.

At step 408, the flag F1 is set to 1. This flag F1 indicates that the current state is a state in which the creep prevention control is being executed.

In step 409, the flag F2 is set to 1
Is set to This flag F2 requires that the hydraulic pressure for engaging the hill hold brake B1 and the second brake B2 be supplied with the spool 132 of the 1-2 shift valve 130 at the raised position, that is, that the solenoid S2 be turned on. Is a flag that indicates

That is, when the creep prevention control is executed, the flags F1 and F2 are both set to 1, so that the flow proceeds to steps 432, 438 and 439, and the spool 132 of the 1-2 shift valve 130 is moved to the raised position. To move, the solenoid valve S2 is turned on.

On the other hand, if it is determined that the condition is not satisfied in any one of the steps 401 to 406, the creep prevention control is released. In this case, the method of release differs depending on which of the conditions in steps 402 to 406 is not satisfied.

If the condition is not satisfied due to the idle contact not being turned on in step 402, in steps 411 and 414, the flags F2 and F2 are respectively set.
After F1 is reset to zero, the routine proceeds to step 413, where the forward clutch C1 is rapidly engaged without performing the smoothing control, and the full clutch is directly engaged.

In step 418, the fill hold brake B1 is released. This release is performed not by turning off the solenoid valve S2 but by increasing the duty ratio with respect to the solenoid valve 240.
Thereafter, the program proceeds to step 440 via 432 (Yes) and 438 (No), and the output is a solid output which returns to the normal shift map. That is, the solenoid output is made based on the vehicle speed V and the throttle opening θ at that time, and at this stage, the control relating to the creep prevention is completely terminated.

On the other hand, when returning from the creep prevention control because conditions other than the accelerator-on are not satisfied, it is first determined at step 416 whether or not the flag F1 is 1. If the creep prevention control has been executed until then, since the determination of Yes is made here,
Proceeding to step 417, it is determined whether or not the forward clutch C1 has been completely engaged, and the process proceeds to step 420 until the forward clutch C1 is fully engaged, so that the forward clutch C1 is engaged while being smoothed.

In this case, steps 432, 43
8 and 439, the solenoids S1 and S2 are both turned on, and the fill hold brake B1 and the second brake B2 are both maintained in the engaged state.

When it is determined that the forward clutch 417 has been completely engaged, the routine proceeds to step 414, where only the flag F1 is reset to 0. At step 413, the forward clutch C1 is maintained in full engagement. In step 418, the fill hold brake B1 is released by raising the duty ratio of the solenoid valve 240 (rather than by turning off the solenoid S2).

Since the flag F2 has not been reset to 0, the process proceeds to steps 432, 438 and 439, and both the solenoids S1 and S2 are kept on. Therefore, the engaged state of the second brake B2 is still maintained.

This engagement state is maintained when the idle contact is turned off in step 402, that is, when the accelerator pedal is depressed, the flag F2 is reset to 0 in step 411, and as a result, in step 438 Is determined to be No, and is maintained until the flow proceeds to step 440.

If it is determined in step 401 that the range is not the D range, the process proceeds to step 415 to determine whether or not the range is two. If it is determined that the range is two, the process proceeds to step 416 and subsequent steps. When it is determined that the range is not the range, the process proceeds to step 421 to determine whether or not the range is the L range, and then the process proceeds to step 416.

If it is not in the L range, it means that the vehicle is not in the forward running range. Therefore, the process proceeds to step 422 and thereafter, the forward clutch C1 is completely disengaged, and both the flags F1 and F2 are reset to 0 (step 423). 435), then step 432 or 4
If the determination at 38 is No, the routine proceeds to step 440, where the output is a solenoid output based on a normal shift map.

According to this embodiment, when the creep prevention control is released by turning on the accelerator pedal, the forward clutch C1 is immediately fully engaged, and the hill hold brake B1 and the second brake B2 are also engaged. At the same time, the vehicle is released, and the first gear is immediately established.

On the other hand, when the anti-creep control is canceled due to a factor other than the accelerator pedal, first, the forward clutch is slowly engaged while smoothing,
Immediately after the engagement is completed, the hill hold brake B1 is released. In this state, the vehicle is on standby with the second brake engaged (while the second speed stage is still formed) until the accelerator pedal is depressed next time. You.

Therefore, since the forward clutch C1 and the hill hold brake B1 are basically controlled as a "set", the anti-backup function always operates when the anti-creep control is executed, while the anti-creep control is performed. When the is released, the anti-backup function is also released with this,
When the brakes are similarly turned off on the same sloping road, it is possible to prevent a problem that the vehicle retreats or does not retreat.

Next, FIG. 6 shows a control flow according to the second embodiment of the present invention.

The difference from FIG. 5 is that when the determination of No is made in step 402, steps 450 and 451 are provided, whereby the step 411 is bypassed or not. .

Specifically, in step 450, it is determined whether or not the throttle opening θ is equal to or greater than a predetermined value θ0.
In step 451, the rate of change Δ of the throttle opening θ
It is determined whether or not θ is greater than a predetermined change rate Δθ0. If at least one of them is not satisfied, step 411 is bypassed. That is, since F2 is not reset, the forward clutch C1 is immediately fully engaged (not smoothed), but the automatic transmission is maintained in the state of the second speed.

Then, when the accelerator pedal is depressed in a state where both steps 450 and 451 are established, F2 is reset for the first time, and as a result, the routine proceeds to step 440, and the solenoid based on the normal shift map is used. Output is provided. Therefore, depending on the vehicle speed V and the throttle opening θ at that time, the vehicle may be downshifted to the first speed stage, or the state of the second speed stage may be left as it is.

According to the control flow of FIG. 6, the downshift from the second speed to the first speed is performed only when necessary, and when this is executed, the torque change due to the depression of the accelerator pedal is performed. Since it is a large time, FIG.
As shown, the shift shock from the second gear to the first gear is masked, and the driver does not feel uncomfortable.

[0105]

As described above, according to the present invention, the anti-creep control is executed, and at the same time, the brake for preventing the reverse movement is actuated, and the control for achieving the high-speed stage of the automatic transmission is executed. In this case, when returning from this control, it is possible to return in a rational sequence, and it is possible to obtain an excellent effect that the return can be made with a small shock and without giving the driver an uncomfortable feeling.

[Brief description of the drawings]

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

FIG. 2 is a skeleton diagram showing a transmission unit of the automatic transmission for a vehicle to which the present invention is applied.

FIG. 3 is a diagram showing engagement and disengagement states of a friction engagement device at each shift speed in the automatic transmission.

FIG. 4 is a hydraulic control circuit diagram showing a part of the hydraulic control device for the automatic transmission.

FIG. 5 is a flowchart showing a control flow executed in the automatic transmission.

FIG. 6 is a flowchart illustrating an example of another control flow.

FIG. 7 is a diagram showing a downshift shock from a second speed to a first speed in comparison with when the torque change is small and when it is large.

[Explanation of symbols]

C1: a forward clutch (clutch to be engaged when achieving forward running); B1: a hill hold brake (a brake to be engaged at the time of reverse control); B2: a second brake (high speed (second speed)) 20: Torque converter, 110: Manual valve, 180: B1 control valve, 200: C1 control valve, 230: Solenoid relay valve, 240: Solenoid valve.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-244955 (JP, A) JP-A-61-55456 (JP, A) Fully open Sho 62-99435 (JP, U) 35816 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (2)

(57) [Claims] When a predetermined condition including an accelerator-off condition is satisfied when a shift range of an automatic transmission is a forward travel range, a frictional engagement element that realizes forward travel is slid, A control device for an automatic transmission for a vehicle configured to perform a specific control of operating a friction engagement element that achieves a second gear and operating a friction engagement element that prevents the vehicle from retreating, while said predetermined condition is the accelerator is turned off, brake
Means for detecting that the vehicle is not satisfied by the key operation , and friction for preventing the engagement of the frictional engagement element for realizing the forward running and the retreat of the vehicle when the predetermined condition is not satisfied by the brake operation . Means for executing only the non-operational operation of the engagement element, means for detecting that the accelerator is turned on after the predetermined condition is not satisfied by the brake operation , and Means for disabling the frictional engagement element for achieving the step, and a control device for an automatic transmission for a vehicle, comprising: 2. When a predetermined condition including an accelerator-off condition is satisfied when the shift range of the automatic transmission is the forward travel range, the friction engagement element that realizes forward travel is slid, and A control device for an automatic transmission for a vehicle configured to perform a specific control of operating a friction engagement element that achieves a second gear and operating a friction engagement element that prevents the vehicle from retreating, while said predetermined condition is the accelerator is turned off, brake
Means for detecting that the key operation has failed, and friction for preventing engagement of the frictional engagement element for realizing the forward running and retreat of the vehicle when the predetermined condition has failed due to the brake operation . Means for executing only the non-action of the engagement element, and means for detecting that at least one of the accelerator opening and the rate of change thereof has become a predetermined value or more after the predetermined condition is not satisfied by the brake operation . Means for disabling the frictional engagement element for achieving the second speed when it is detected that at least one of the accelerator opening and the rate of change is equal to or greater than a predetermined value. Control device for an automatic transmission for a vehicle.