JPH04194455A - Creep control device of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To prevent generation of a trouble of suddenly increasing creep torque during stopping by feedback controlling a slip amount of a forward clutch so that an output shaft rotational speed of a torque converter obtains a target output shaft rotational speed. CONSTITUTION:There are provided at least an input/output shaft rotational speed detecting means for detecting an input/output shaft rotational speed of a torque converter and a transmission torque arithmetic means for obtaining transmission torque of a forward clutch from the input/output shaft rotational speed of the torque converter and a transmission capacity coefficient of the torque converter in this input/output shaft rotational speed. A target output shaft rotational speed of the torque converter is set by a target output shaft rotational speed setting means so that a product of the transmission torque of the forward clutch and the output shaft rotational speed of the torque converter is in a fixed value, and a slip amount of the forward clutch is controlled by a slip amount feedback control means so that the output shaft rotational speed of the torque converter obtains the target output shaft rotational speed.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a device for reducing and controlling creep in an automatic transmission for a vehicle.

[Conventional technology]

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, and the gear position of the gear transmission is controlled by the vehicle speed and the accelerator pedal. The gear shift pattern is configured to shift according to a predetermined shift pattern depending on the amount of depression of the pedal. As is well known, the manual shift range of an automatic transmission has shift ranges such as drive range, neutral range, parking range, etc., but when this manual shift range is set as the drive range, , so-called creep occurs, which causes the vehicle to heal little by little. This is because when the drive range is set, the gear transmission is in the first gear state and the engine is rotating at idle speed, so some torque is transmitted to the wheels via the torque converter. This is for the purpose of coming. This creep phenomenon can be canceled by changing the manual shift range to the neutral range. However, when driving, especially when starting and stopping frequently occur, it is possible to eliminate the creep phenomenon by changing the manual shift range to the neutral range. Brakes are often used to suppress this creep phenomenon. In view of these points, conventionally, when the shift range is set to the forward travel range, the accelerator pedal is released, the foot brake is depressed, and the vehicle speed is detected to be substantially zero, the gear transmission A control system has been proposed that automatically creates a neutral state by slipping the forward clutch (clutch that is engaged when moving forward) to prevent creep. In addition, when executing this control, if the forward clutch is completely released, the time lag at the time of starting will become large. The difference between the turbine rotation speed (turbine rotation speed) Nt and the input shaft rotation speed (pump rotation speed) Ni (
Nt - Ni ) or these ratios (Nt/Ni) are compared with the target value, and the forward clutch is maintained in a so-called half-clutch state to the extent that the vehicle does not move forward, thereby preventing creep and reducing responsiveness during starting. A technology has been disclosed that achieves both. In addition, if the occurrence of creep is prevented by setting the forward clutch in the half-clutch state, if this continues for too long, there will be concerns about the durability of the forward clutch. 76026 also discloses a technique in which the creep control is stopped when the duration of the creep control exceeds a predetermined value.

[Problem to be solved by the invention]

However, if Cree-1 control is suddenly stopped after a predetermined period of time has elapsed, the creep torque will increase rapidly, and the driver will have to press the foot brake harder to maintain the stopped state. become. The present invention has been made in view of such conventional problems, and it prevents the problem of creep control being suddenly stopped when the driver does not intend it, and also improves the durability of the forward clutch. An object of the present invention is to provide a creep control device for a vehicle automatic transmission that can reliably guarantee the occurrence of creep.

[Means to solve the problem]

As the gist of the present invention is shown in FIG. 1, when the shift range is set to the forward travel range, the accelerator pedal is released, the foot brake is depressed, and the vehicle speed is detected to be substantially zero, , a creep control device for automatic transmissions for vehicles that slips the forward clutch to create a neutral state and prevent creep! - means for detecting at least the input/output shaft rotational speed of the torque converter;
means for determining the transmission torque of the forward clutch from the input/output shaft rotational speed of the torque converter and the transmission capacity coefficient of the torque converter at the input/output shaft rotational speed; and the transmission torque of the forward clutch and the output shaft of the torque converter. Means for setting a target output shaft rotation speed of the torque converter so that the product with the rotation speed is constant; and means for setting a slip of the forward clutch so that the output shaft rotation speed of the torque converter becomes the target output shaft rotation speed. The above object is achieved by providing a means for feedback controlling the amount.

[Effect]

In the present invention, the target output shaft rotation speed of the torque converter is set so that the value obtained by multiplying the transmission torque of the forward clutch by the output shaft rotation speed of the torque converter, that is, the transmission energy rate of the torque converter is constant,
The slip amount of the forward clutch is feedback-controlled so that the output shaft rotation speed of the torque converter becomes the target output shaft rotation speed. The transmission torque of the forward clutch corresponds to the creep torque and further corresponds to the transmission torque of the torque converter. Therefore, by controlling the transmission torque of the torque converter multiplied by the output shaft rotational speed of the torque converter to be constant, the transmission energy rate of the forward clutch can be maintained constant. As a result, even if creep control is executed for a long time, the durability of the forward clutch will not be impaired. 1. Creep control is no longer suddenly stopped and creep 1 torque does not suddenly increase. Note that the transmission torque of the torque converter can be determined by calculating the transmission capacity coefficient at that time if the input/output shaft rotational speed of the torque converter is known. The input shaft rotational speed of the torque converter matches the engine rotational speed, and since the engine rotational speed is already provided for other control purposes,
・In the end, for this control, the detection system only needs to be the rotational speed of the output shaft of the torque converter.

【Example】

Embodiments of the present invention will be described in detail below based on the drawings. FIG. 2 shows an overall outline of a vehicle automatic transmission to which an embodiment of the present invention is applied. This automatic transmission includes a torque converter section 20, an overdrive mechanism section 40, and an underdrive mechanism section 60 with three forward speeds and one reverse speed. The torque converter section 20 includes a pump 21, a turbine 22, a stator 23, and a lock-up clutch 24.
1, which transmits the output of the crankshaft 10 of the engine 1 to the overdrive mechanism section 40. The lock-up clutch 24 is engaged when conditions are met and connects the pump 21 and the turbine 22. As a result, fuel consumption efficiency is improved. The overdrive mechanism section includes a sun gear 43, a ring gear 44, a planetary pinion 42, and a carrier 41.
The rotational state of the planetary gear system is controlled by a clutch co, a play-1rBo, and a one-way clutch FO. The underdrive mechanism section 60 includes a common sun gear 6
1, ring gear 62.63, planetary binion 64.
65 and carriers 66 and 67, and the rotation state of these 2M planetary gear devices and the connection state with the overdrive mechanism are controlled by clutch C1,
C2, brakes 81 to B3 and one-way clutches F1, F
It is controlled by 2. Since the specific structure of the transmission section of this automatic transmission is well known in itself, only a skeleton diagram is shown in FIG. 2, and detailed explanation thereof will be omitted. This automatic transmission includes a transmission section as described above,
and a computer 84. The computer 84 has a throttle opening θ to reflect the load of the engine 1.
Throttle sensor 8o with idle switch to detect
, a vehicle speed sensor (rotational speed sensor of the output shaft 7o) 82 that detects the vehicle speed No., a foot brake switch 90 that detects that the foot brake is turned on. Signals for various controls such as an engine rotation speed sensor 92 that detects the engine rotation speed, an engine cooling water temperature sensor 94, and a 00 rotation speed sensor 99 that detects the rotation speed of the clutch CO are input. The rotational speed of this clutch CO is 131st! The rotational speed of the output shaft of the turbine 22, that is, the torque converter section 20, is the same as that of the third speed. Therefore, it can be sufficiently used as the output shaft rotational speed (turbine rotational speed) Nt of the torque converter section 20 when executing CREE-1 control. The computer 84 drives and controls the solenoid valves in the hydraulic control circuit 86 according to a preset throttle opening/vehicle speed shift point map, and selects the engagement combinations of each clutch, brake, etc. as shown in FIG. Go and change gears. In this automatic transmission, clutch C1 corresponds to a forward clutch that is slipped during creep control. As is clear from FIG. 3, when the shift range is in the forward travel range, the forward clutch C1 is engaged and forward travel is possible. 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. This causes the automatic transmission to shift to a neutral state. In this automatic transmission, when performing creep control, the brake B1 is simultaneously engaged in order to prevent the vehicle from moving backward, that is, to activate a so-called hill hold function. Next, a hydraulic control circuit that executes the creep control and hill hold control will be explained using FIGS. 4 and 5. Note that FIG. 5 schematically shows the main parts of the hydraulic control circuit shown in FIG. 4. In the figure, reference numeral 110 indicates a manual shift valve. This manual shift valve 110 has a hydraulic input port 114. The hydraulic input boat 114 receives line pressure P sucked up by the oil pump 120 and regulated by the primary regulator valve 124.
L is supplied via oil passage 126. This manual shift valve 110 is a manual shift lever (not shown).
The hydraulic input boat 114 is connected to the D range boat 116 when the manual shift range is the D range. Further, when the manual shift range is the S range, the hydraulic input boat 114 is connected to the S range port 118. D range boat 116 is connected to port 146 of 2-3 shift valve 140 via oil &11300.302,
S range boat 118 is connected to port 148 of 2-3 shift valve 140 by oil line 304. The 2-3 shift valve 140 has a spool 142. Spool 142 is in the raised position shown in the right half of the figure when hydraulic pressure is not supplied to port 144, communicating port 146 with port 150, and connecting port 146 to port 150.
48 is connected to port 152. On the other hand, when hydraulic pressure is supplied to port 144, it is in the lowered position shown in the left half of the figure, cutting off communication between port 146 and port 150, and also blocking communication between port 146 and port 150.
The port 152 is connected to the drain port 154.
It will be communicated to. Hydraulic pressure is supplied to port 144 in a well-known manner by a solenoid valve (not shown), and hydraulic pressure is supplied to port 144 only when the third gear or overdrive gear is achieved. Therefore, the spool 142 is in the raised position when the first gear or the second gear is achieved, and is in the lowered position when the third gear or the overdrive gear is achieved. Port 150 is communicated with port 186 of 81 control pulp 180 by oil passage 306 . Port 1
52 is communicated with port 172 of check valve 170 via oil passage 308, second coast modulator valve 16Q, and oil passage 310. In addition to the inlet boat 172, the check valve 170 has another inlet port 174 and one outlet port 176. When the hydraulic pressure is supplied to the inlet port 174, the inlet port 172 is closed. Inlet port 174 is connected to port 188 of brake control valve 180 by oil line 312, and outlet port 176 is connected to port 136 of 1-2 shift valve 130 by oil N314. 1-2 shift valve 130 has a spool 132. Spool 132 is in the raised position shown in the left half of the figure when hydraulic pressure is not being supplied to port 134 and communicates with ports 136 and 138, whereas boat 134
When hydraulic pressure is being supplied to the drain boat 139, the boat 136 and 138 are cut off at the lowered position 1 shown in the right half of the figure, and the boat 138 is communicated with the drain boat 139. Hydraulic pressure is supplied to the boat 134 only when the first gear is achieved by the action of a solenoid valve (not shown), so that the spool 132 can move upward when the second gear 1, the third gear, or the overdrive gear is achieved. The lower position is reached only when the first gear is achieved. Boat 138 is connected to brake B1 by oil line 316. B1 control valve 180 has a spool 182 and a plug 184. Spool 182 is connected to boats 186 and 188 when in the raised position shown in the right half of the figure.
The drain boat 198 is connected to the drain boat 198 by blocking the boats 190 and 192. On the other hand, when in the lowered position shown in the left half of the figure, the boat 186 is closed, the boat 188 is communicated with the drain boat 187, and the boats 190 and 192 are communicated with each other. Boat 190 is connected to D range boat 116 of manual shift valve 110 by oil line 314 and oil line 300, and boat 192 is connected to boat 208 of C1 control valve 200 by oil line 316. The spool 182 is driven by the oil pressure applied to the boats 194 and 196, and when a signal oil pressure Ps of a predetermined value p5set or more is supplied to at least one of the boats 194 and 196, the left half! , that is, located at the hill hold control release position. Also, boats 194 and 19
Signal oil pressure Ps of predetermined value p 5set or more for any of 6
When is not being supplied, it is located at the right half position, that is, the hill hold control position. The boat 194 is connected to oil R320 through an oil passage 318 and is supplied with a signal oil pressure Ps from the oil passage 320. Further, the boat 196 is supplied with throttle oil pressure or servo oil pressure (engaging pressure) of the clutch C1 through an oil passage (not shown). The solenoid valve 240 is configured to generate a signal pressure PS in the oil passage 320 according to the duty ratio of the pulse signal applied to the electromagnetic coil. The solenoid valve 240 is constituted by a so-called normally closed type solenoid valve, so that the signal oil pressure Ps of the oil passage 320 decreases as the duty ratio applied to the electromagnetic coil increases. The oil passage 320 is connected to the oil passage 126 via the throttle 280, the oil passage 322, the modulator valve 250, and the oil passage 324 to be supplied with the original oil pressure. Pressure-regulated modulated hydraulic pressure PLI is supplied. The oil passage 320 is connected to the boat 194 of the B1 control valve 180 by an oil passage 318, and is connected to the C1 control valve 20 via an oil passage 326 and a throttle 282.
It is communicatively connected to the boat 210 of 0. The C1 control valve 200 has spools 202 and 2
and two plugs 204 and 206. Spool 202 is connected to oil passage 3 by oil passage 328.314.
Boat 21 connected to 00 and supplied with line pressure PL
The hydraulic pressure of the outlet boat 214 is regulated by controlling the degree of communication with the second drain boat 216. This pressure adjustment value increases in accordance with an increase in the biasing force applied to the spool 202 by the compression coil spring 218 and the pressing force directly applied to the spool 202 by the plugs 204 and 206. Exit boat 214
is connected to clutch C1 via throttle 284 and oil passage 330. Further, the oil passage 328 and the oil passage 330 are connected by the oil passage 314 and the check valve 260. This check valve 260 is connected to the oil passage 328 from the oil passage 330.
It is configured to allow only oil flow to, that is, oil drain flow. Manual shift range is set to D range.
When the first gear is established, the 1-2 shift valve 1
The spool 132 of the 2-3 shift valve 140 is in the lowered position and the spool 142 of the 2-3 shift valve 140 is in the raised position. While creep control and hill hold control have not yet started and an off signal is given to solenoid valve 240, oil! ! The signal oil pressure Ps of &320 is set to the same oil pressure as the output oil pressure Pi of the modulator valve 250, and this oil pressure is supplied to the boat 194 of the 81 control valve 180 and the boat 210 of the C1 control valve 200. Therefore, at this time, the spool 180 of the B1 control valve 180 is located at the left position, that is, the hill hold control starting position, thereby closing the boat 186 and communicating the boat 188 with the drain port 187. Also, by communicating the boat 190 with the boat 192, the line pressure PL from the oil 1i% 300.314 is increased to the oil path 3.
Boat 20 of C1 control valve 200 via 16
8, and from this point on, the 01 control pulp 200 is located at the left position, that is, the normal mode position, by the action of the line pressure PI supplied to the boat 208 in addition to the signal oil pressure PS supplied to the boat 210. As a result, the drain boat 216 is completely closed, so that the line pressure PL applied to the boat 212 is not reduced and is directly introduced into the clutch C1 from the boat 214 via the oil path 330. Therefore, at this time, clutch C
1 is fully engaged and the first gear is achieved. Also, since the boat 186 of the B1 control valve 180 is closed, the boat 188 is connected to the drain, and the boat 136 of the 1-2 shift valve 130 is also closed, so the boat 13
8 is connected to the drain, no hydraulic pressure is supplied to the brake B1, and the brake B1 maintains a released state. When the manual shift range is set to 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 at a predetermined level close to zero. When the value falls below the value, a pulse signal is given to the solenoid valve 240 to perform creep control and hill hold control, and the deinity ratio is increased over time. As the duty ratio increases, the signal oil pressure Ps of the oil passage 320 gradually decreases over time, and when the signal oil pressure Ps decreases to a predetermined value P5set, the spool 182 of the B1 control pulp 180
is switched to the right position in the figure, and the communication port of the boat 188 is switched from the drain boat 187 to the boat 186. Also, the communication boat of the boat 192 is switched from the boat 190 to the drain boat 198. Therefore, the line pressure PL is no longer supplied to the boat 208, so the pressure regulation value of the C1 control valve 200, that is, the engagement pressure of the clutch C1 is set by the signal oil pressure Ps given to the boat 210, and as the signal oil pressure PS decreases, Drain boat 216 is now opened. As a result, the engagement pressure supplied to the clutch C1 from the boat 214 decreases, causing the clutch C1 to slip. This puts the automatic transmission in a state similar to when it is in neutral, reducing idle vibration and preventing creep. That is, creep control is executed. On the other hand, at this time, since the boats 186 and 188 of the 81 control valve 180 are in communication with each other as described above, the spool 142 of the 2-3 shift valve 140 achieves the raised position, that is, the first gear or the second gear. When the line pressure PL of the D range port 116 of the manual shift valve 110 is in the switching position, the line pressure PL of the D range port 116 of the manual shift valve 110 is
Boats 146 and 150 of -3 shift valve 140, oil passage 306, boat 18 of B1 control valve 180
6 and 188, oil passage 312, check valve 170, and oil #1314 to boat 1 of 1-2 shift valve 130.
It reaches up to 36. Therefore, at this time, if the spool 132 of the 1-2 shift valve 130 is in the raised position, that is, the 2nd gear, 3rd gear, etc. Pressure PL is supplied to brake B1 from port 138 via oil M316, and plate 1rB1 is engaged to fix the sun gear.Therefore, rotation of each of the front sun gear and rear sun gear is prevented, and one-way clutch 92 The output shaft is prevented from rotating in the backward direction of the vehicle, and so-called hill hold control is executed. However, in this embodiment, the signal oil pressure Ps is controlled by the I!11 control flow as shown below. , the rotational speed of clutch CO (=turbine rotational speed Nt) is feedback-controlled (near PSSet) so that it reaches the target value, and the amount of slip of clutch C1 is finely adjusted. This control flow is shown in Fig. 6. First, in step 202, various data for executing creep control are read.Here, a signal indicating a shift range, an idle switch signal, a foot brake signal, a vehicle speed signal, an engine rotation speed signal, an engine cooling water temperature signal, and a turbine rotation speed signal (rotation speed signal of clutch CO) are input. In step 204, it is determined based on these signals whether or not conditions for creep control are satisfied. In this embodiment, ■shift range is It is in the forward driving range, ■ The foot brake signal is turned on, ■ The idle contact signal is turned on, ■ The vehicle speed is detected to be substantially zero (stopped), ■ The engine rotation speed is below a predetermined value, and ■ The engine cooling It is determined that the conditions for creep control are not met when the water temperature is above a predetermined value and the oil temperature of the automatic transmission is above a predetermined value. The conditions (■ to ■) that correspond to the conditions that hold true correspond to the conditions that are detected for confirmation from the viewpoint of fail-safe.In step 208, the engine rotation speed (= rotation speed of the pump 21 of the torque converter) , that is, the input shaft rotational speed of the torque converter 20) and the target turbine rotational speed (the rotational speed of the clutch CO, that is, the output shaft rotational speed of the torque converter 20) Nt is set by interpolating from the relationship shown in FIG. 7. This setting The method will be described in detail later. In step 210, the difference ΔNt between the target turbine rotation speed Nt and the actual turbine rotation speed nt is determined. In step 212, the absolute value of ΔNt and the constant A are compared in magnitude. , when the absolute value of ΔNt is larger than the constant A, D0CX is set in step 222 as the creep control start mode.
A duty ratio corresponding to t is output to the linear solenoid 240. Here, D is the initial duty ratio, C is a constant, and t is time. As a result, the duty ratio of the linear solenoid 240 gradually increases, and the (forward) clutch C1 eventually begins to slip due to the aforementioned hydraulic circuit. On the other hand, when the absolute value of ΔNt is smaller than the constant A, the process proceeds to step 214 as a mode in which creep control is being performed, and here the linear solenoid is 2
The duty ratio to be outputted to 40 is calculated and outputted to the linear solenoid. In step 216, during the start mode of creep control,
It is determined whether the turbine rotational speed nt is approaching the target turbine rotational speed Nt to some extent. Note that the symbol E in the figure is set by a constant or a map. As a result, if it is determined that the vehicle has approached to a certain extent, the process proceeds to step 218 to engage the brake B1 for hill hold, energizes the solenoid for engaging the brake B1, and enters hill hold control. On the other hand, if the creep control conditions are not satisfied in step 204, the process proceeds to step 220, where the linear solenoid 240 is de-energized, and at the same time, the B1 solenoid is also de-energized. As a result, the first speed stage of the normal drive range is formed. Next, the setting of the target turbine rotation speed Nt in step 208 will be explained in detail. FIG. 7(A) shows the target set value of the idle rotation speed in a numerical engine. In vehicles with automatic transmissions, this is to prevent engine stalling or rotational fluctuations when shifting from neutral range or parking range to other ranges, or when turning on the air conditioner switch. , the target value of the idle rotation speed is changed depending on the shift range and the on/off status of the air conditioner switch.6For example, when the air conditioner is turned on and the engine load increases, the target idle rotation speed is set high. In this case, for example, in the conventional Japanese Patent Application Laid-Open No. 59-17051, creep control is discontinued when the idle speed is set high, such as when an air conditioner is turned on, but in this embodiment, creep control is Air conditioner turns from off to on during control,
Or, even if the creep control changes from on to off, the creep control will not be canceled. This is because the transmission energy rate of clutch C1 is kept unchanged, so there will be no particular problem even if it continues to be executed for a long time. be. FIG. 7(B) shows the relationship between the target turbine rotation speed Nt and the like with respect to the engine rotation speed ne. The creep torque (transmitted torque of clutch C1) is the same as the transmitted torque of the torque converter in the case of the first to third speeds. The transmission torque T of the torque converter is expressed by the following equation. T = Cx ne” --(1) Here, C is the transmission capacity coefficient of the torque converter, and for the same torque converter, the speed ratio of the torque converter is e = Nt/n
It changes depending on e. Therefore, as shown in FIG. 7(B), the transmission torque T1 when the air conditioner is off is multiplied by the turbine rotation speed Nt1, whereas the transmission torque T2 when the air conditioner is on is multiplied by the turbine rotation speed Nt2. If the turbine rotational speed Nt2 is set so that the multiplied value is the same value A, it is possible to control the transmission energy rate of the forward clutch to be constant regardless of disturbances such as turning on or off the air conditioner. become. In addition, in FIG. 7(B),
Although the target turbine rotation speed Nt was determined based on each target value, it is also possible to change and set the target turbine rotation speed Nt in real time based on each actual measurement value). If the idle rotation speed is more finely divided depending on whether the air conditioner is on or off, the magnitude of the electrical load, or the shift position, the target turbine rotation speed Nt for the set idle rotation speed is set in exactly the same way. become. Note that since the transmission energy rate of the clutch C1 is kept constant, when the idle rotational speed of the engine changes, the creep torque generated accordingly changes slightly. However, in this case, no particular problem will occur if the creep torque is set to a value that will not cause the vehicle to start moving even if the creep torque increases.

【Effect of the invention】

As explained above, according to the present invention, the air conditioner is turned on.
Even if the idle rotation speed increases or decreases due to disturbances such as turning off, the transfer energy rate of the forward clutch can always be controlled to be constant. Therefore, this transfer energy rate is set to a value that takes into account the durability of the forward clutch. As a result, even if creep control is executed for a long time, there is no need to stop it midway. As a result, it is possible to prevent the problem of sudden increase in creep torque during stoppage.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the gist of the present invention, and FIG. 2 is a block diagram showing the gist of the present invention.
FIG. 3 is a skeleton diagram showing the transmission section of the automatic transmission for a vehicle to which the present invention is applied. 4 is a hydraulic control circuit diagram showing a part of the hydraulic control device of the automatic transmission; FIG. 5 is a hydraulic control circuit diagram schematically showing the functions of the main parts of the circuit diagram in FIG. 4; Fig. 6 is a flowchart showing the control flow executed by the automatic transmission, Fig. 7 (A) is a line section showing the target value of the idle rotation speed, and Fig. 7 (B) shows the setting of the target turbine rotation speed. It is a line diagram showing various related numerical values when doing so. C1...Clutch (forward clutch), B1...
・Brake (brake to be engaged during hill hold control), 20...torque converter section, 110...manual valve, 180...B1 control valve, 200...C
1 control valve, 230... Solenoid relay valve, 240... Solenoid valve, ne... Engine rotation speed (pump rotation speed), nt
...Turbine rotation speed (rotation speed of clutch CO), Nt...Target turbine rotation speed, T...Torque converter transmission torque (creep torque).

Claims (1)

[Claims] (1) The shift range is set to the forward travel range, the accelerator pedal is released, the foot brake is depressed, and
A creep control device for an automatic transmission for a vehicle that prevents creep by slipping a forward clutch to form a neutral state when the vehicle speed is detected to be substantially zero, at least controls the rotational speed of the input and output shafts of the torque converter. means for detecting the transmission torque of the forward clutch from the input/output shaft rotational speed of the torque converter and the transmission capacity coefficient of the torque converter at this input/output shaft rotational speed; and the transmission torque of the forward clutch and the transmission torque of the forward clutch. means for setting a target output shaft rotation speed of the torque converter so that its product with the output shaft rotation speed of the torque converter is constant; A creep control device for an automatic transmission for a vehicle, comprising: means for feedback controlling the slip amount of the forward clutch.