JPH0694115A - Hydraulic controller for automatic transmission - Google Patents

Abstract

PURPOSE:To contrive speed shift action having no speed shift shock at the time of speed shift based on the change of engine load by correcting on the basis of the change rate of the engine load a term relating to the change rate of an input rotation number in a relation expression to operate operation oil pressure at the time of speed shift. CONSTITUTION:In the case of what inputs the respective output signals of a throttle opening sensor 9, a vehicle speed sensor 10, a turbine rotation number sensor 11, a torque sensor 12 and a road surface slope sensor 13 into a controller 7 and by this, controls a hydraulic control circuit 6 and conducts speed shift control, line pressure P is controlled by means of a duty solenoid valve 62, and a line pressure control signal to be impressed on this is operated on the basis of a predetermined relation expression. That is, when turbine torque is tauT, and a speed shift start rotation number is NS, and a speed shift finish rotation number is NE, and a target speed shift time determined from a throttle change rate and a road surface slope is T and variables to be changed according to the kind of speed shift are made to be A, B, operation is carried out from the expression of P (pressure value)=A (tauT-B (NE-NS)/T.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission mounted on an automobile, and more particularly to a hydraulic control device for an automatic transmission in which a fastening force of a friction element is hydraulically controlled.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile is a combination of a torque converter to which an engine output is input and a speed change mechanism driven by the output of the converter. It is configured so that a plurality of friction elements such as a brake are selectively operated to automatically shift to a predetermined gear, and in this type of automatic transmission, the fastening force of each friction element is hydraulic. Is controlled by.
In this case, if the operating oil pressure supplied to the friction element that is engaged or released at the time of gear shifting is low, the friction element unnecessarily slips and the gear shifting time becomes undesirably long, resulting in poor gear shifting feeling. On the contrary, if the hydraulic pressure supplied to the friction element is high, the shift time becomes too short and a large shift shock is generated.

Therefore, it has been considered to set the working hydraulic pressure to be supplied to the friction element at the time of shifting so that the shifting operation is completed within a predetermined target time. For example, special announcement 5
Japanese Patent Laid-Open No. 8-501477 discloses that the hydraulic pressure of the friction element at the time of gear shifting is set so that the gear shifting operation is completed in a certain time.
A technical idea of setting in proportion to the sum of the engine output torque, the engine speed and a constant coefficient is disclosed. This is focused on the fact that the engine speed is accelerated or decelerated so that the engine speed corresponds to the output speed of the speed change mechanism at the time of shifting, without causing excessive shift shock. The shift operation can be completed in a short time.

[0004]

However, in the prior art described in the above publication, the working hydraulic pressure of the friction element is not set in consideration of the change of the engine load and the road surface gradient at the time of gear shifting. The following issues remain to be solved.

That is, in this type of automatic transmission, a gear shifting operation may be performed based on a change in engine load, but in that case, a gear shifting operation different from the normal state is required. In other words, during downshifts due to an increase in engine load, a responsive shift operation is required even if some shock occurs, while at the time of upshifts due to a decrease in engine load, responsiveness is reduced. Even at the expense of, a shift operation with less shock is required. In that case, if the hydraulic pressure of the friction element is set so that the shift time is constant, not only is the shift time too long to obtain a good sense of acceleration when shifting due to an increase in engine load, but also On the contrary, at the time of shifting up due to the reduction of the engine load, the shifting time is too short and a large shift shock will occur.

Moreover, when shifting up in the half throttle state in which the accelerator pedal is returned to the half open state,
Although the driver expects a sense of deceleration, a shock unexpectedly occurs and causes discomfort.

On the other hand, the following inconvenience also occurs due to the road surface gradient in the traveling direction of the vehicle. That is, for example, at the time of shift-down gear shifting, the friction element engaged at the high speed stage is released, and the speed change mechanism becomes neutral.
The input rotation speed or the rotation speed of the transmission mechanism increases. Then, for example, when the one-way clutch provided in the power transmission path shifts from the idling state to the power transmission state due to the increase in the rotation speed, the engine output is transmitted to the wheel side and the gear shifting operation ends. At that time, a transient vibration occurs due to the torsional rigidity of the vehicle body. The strength of the vibration depends on the relative rotational acceleration before and after the one-way clutch. That is, the greater the relative rotational acceleration, the stronger the vibration. In that case, in the ascending state, the rotational speed on the output side of the one-way clutch is decelerated due to the gravitational acceleration acting on the vehicle body, so that the relative rotational acceleration before and after the one-way clutch becomes large, so that the shift time is flat. This is relatively shorter than the road, and the vibration becomes stronger, which may cause the driver to feel extreme discomfort. On the contrary, in the down state, the rotational speed on the output side of the one-way clutch is accelerated due to the gravitational acceleration, so the relative rotational acceleration before and after the one-way clutch becomes small, and the shift time is longer than on a flat road. Therefore, the shift feeling is deteriorated.

The present invention addresses the above-mentioned problems in an automatic transmission in which the fastening force of a friction element is controlled by hydraulic pressure, so that the operating hydraulic pressure supplied to the friction element during gear shifting can be set appropriately. The purpose is to

[0009]

That is, a hydraulic control device for an automatic transmission according to the invention of claim 1 of the present application (hereinafter referred to as the first invention) supplies to a friction element forming a power transmission path in a speed change mechanism. Operation for setting the operating oil pressure at the time of shifting based on a predetermined relational expression consisting of a first term related to the input torque of the speed change mechanism and a second term related to the rate of change of the input speed of the speed change mechanism. The hydraulic pressure setting means, the engine load detecting means for detecting the engine load, and the second term in the above relational expression based on the rate of change of the engine load detected by the engine load detecting means at the time of shifting based on the change of the engine load. By setting the operating hydraulic pressure setting state changing means for changing the setting state of the operating hydraulic pressure by the operating hydraulic pressure setting means so that the shift time corresponding to the engine load change rate is obtained by the correction. Characterized in that was.

The invention of claim 2 of the present application (hereinafter referred to as the second
The hydraulic pressure control device for an automatic transmission according to the invention relates to the first term relating to the input torque of the speed change mechanism and the speed change hydraulic pressure supplied to the friction element forming the power transmission path in the speed change mechanism. A hydraulic pressure setting means for setting based on a predetermined relational expression consisting of a second term relating to the change rate of the input speed of the mechanism, an engine load detecting means for detecting an engine load, and a shift accompanying an increase in the engine load. At the time of downshift, the second in the above relational expression based on the change rate of the engine load detected by the engine load detecting means.
By correcting the item, the operating hydraulic pressure setting state changing means for changing the setting state of the operating hydraulic pressure by the operating hydraulic pressure setting means is provided so that the shift time becomes shorter as the increase rate of the engine load increases. To do.

The hydraulic control device for an automatic transmission according to the invention of claim 3 of the present application (hereinafter referred to as the third invention) is an operating hydraulic pressure at the time of gear shifting, which is supplied to a friction element forming a power transmission path in a gear shift mechanism. Is set based on a predetermined relational expression consisting of a first term related to the input torque of the speed change mechanism and a second term related to the rate of change of the input speed of the speed change mechanism, and an engine. By correcting the second term in the above-mentioned relational expression based on the rate of change of the engine load detected by the engine load detection means at the time of shift-up shift due to the decrease of the engine load, , And a working hydraulic pressure setting state changing means for changing the setting state of the working hydraulic pressure by the working hydraulic pressure setting means such that the shift time becomes longer as the engine load reduction rate increases. Characterized in that was.

Further, the hydraulic control device for an automatic transmission according to the invention of claim 4 of the present application (hereinafter referred to as the fourth invention) is the relational expression for setting the working hydraulic pressure in the configurations of the first to third inventions. As a second term related to the rate of change of the input rotational speed, an element that divides the difference between the input rotational speeds before and after the shift by the time between them is provided, and the operating hydraulic pressure setting state changing means is used to change the engine load based on the time. It is characterized in that the correction is made based on the rate.

On the other hand, the invention of claim 5 of the present application (hereinafter referred to as the fifth
The hydraulic pressure control device for an automatic transmission according to the invention relates to the first term relating to the input torque of the speed change mechanism and the speed change hydraulic pressure supplied to the friction element forming the power transmission path in the speed change mechanism. An operating oil pressure setting means that is set based on a predetermined relational expression consisting of a second term related to the rate of change of the input speed of the mechanism; a road surface gradient detecting means that detects a road surface gradient in the traveling direction of the vehicle; An operation of changing the setting state of the operating hydraulic pressure by the operating hydraulic pressure setting means so that the shift time corresponding to the road surface gradient is achieved by correcting the second term in the above relational expression based on the road surface gradient detected by the detecting means. A hydraulic pressure setting state changing means is provided.

[0014]

According to the above construction, the following operation can be obtained.

That is, in any of the first to fifth inventions, the operating hydraulic pressure supplied to the friction element forming the power transmission path in the speed change mechanism during the speed change is the first related to the input torque of the speed change mechanism. Since it is set based on a predetermined relational expression consisting of a term and a second term related to the rate of change of the input speed, the gear shifting operation can be completed in a short time without causing an excessive shock. It can be done appropriately.

Moreover, according to the first aspect of the present invention, at the time of gear shift based on the change of the engine load, the second term relating to the change rate of the input speed in the above relational expression is corrected based on the change rate of the engine load. As a result, the setting state of the hydraulic pressure is changed so that the shift time corresponds to the rate of change of the engine load.Therefore, when shifting down due to an increase in the engine load, the shift time is shortened to reduce the acceleration response. The shift operation with good performance is performed, and when shifting up due to the reduction of engine load, the shift time is lengthened to perform the shift operation with almost no shift shock.
It is possible to perform an appropriate shift operation according to the request.

Further, according to the second aspect of the invention, in the shift-down gear shift accompanying the increase of the engine load, the setting state of the working hydraulic pressure is changed so that the gear shift time becomes shorter as the increase rate of the engine load increases. Therefore, it is possible to perform a gear shift operation with good acceleration response without causing an extreme deterioration of gear shift shock.

Further, according to the third aspect of the present invention, at the time of shift-up shifting accompanying a decrease in engine load, the setting state of the hydraulic pressure is changed such that the shift time becomes longer as the rate of decrease in engine load increases. Thus, it becomes possible to perform the gear shifting operation with less gear shifting shock without lengthening the gear shifting time.

Further, according to the fourth aspect of the present invention, in the second term relating to the rate of change of the input rotational speed in the relational expression for setting the operating hydraulic pressure, the difference between the input rotational speeds before and after the shift is gradually divided by the time therebetween. Since the element is provided and the time is corrected based on the rate of change of the engine load, an appropriate hydraulic pressure corresponding to the desired shift time can be obtained.

On the other hand, according to the fifth aspect of the invention, the second aspect relating to the rate of change of the input speed in the relational expression for setting the hydraulic pressure is set.
By correcting the term based on the road surface gradient in the traveling direction of the vehicle, the setting state of the hydraulic pressure is changed so that the shift time corresponding to the road surface gradient is obtained.
The shift operation can be more appropriately performed so as to be completed in a short time without causing an excessive shock.

[0021]

EXAMPLES Examples of the present invention will be described below.

As shown in FIG. 1, an automatic transmission 3 which constitutes a power plant 2 together with an engine 1 receives a torque converter 4 connected to an output shaft 1a of the engine 1 and an output rotation of the torque converter 4. Transmission mechanism 5
And a hydraulic control circuit 6 for controlling the supply and discharge of the line pressure supplied to a plurality of friction elements (not shown) that switch the power transmission path of the speed change mechanism 5.

The power plant 2 is provided with a controller 7 for performing various controls. The controller 7 detects the opening degree of a throttle valve 8 provided in the intake passage of the engine 1. A signal from the sensor 9, a signal from the vehicle speed sensor 10 that detects the vehicle speed of the vehicle, and a turbine speed sensor 1 that detects the output speed (turbine speed) of the torque converter 5.
1, the signal from the torque sensor 12 that detects the output torque of the torque converter 4, and the signal from the road surface gradient sensor 13 that detects the road surface gradient in the traveling direction of the vehicle are input to control the hydraulic pressure. The shift solenoid valves 61 to 61 included in the circuit 6 perform shift control, and the duty solenoid valve 62 also included in the hydraulic control circuit 6 performs line pressure control.

Here, the structure of the portion related to the line pressure control in the hydraulic control circuit 6 will be schematically described.

That is, as shown in FIG. 2, a regulator valve 64 for adjusting the working hydraulic pressure is provided between the oil pump 63 and the friction element 14, and the control pressure of the regulator valve 64 is the duty ratio. By the duty control by the solenoid valve 62, the line pressure on the downstream side of the regulator valve 64 is adjusted to the pressure corresponding to the line pressure control signal output from the controller 7.

Next, the line pressure control, which is a characteristic part of this embodiment, will be described. Specifically, the line pressure control is performed as follows according to the flowchart of FIG.

That is, the controller 7 performs step S1.
After reading various signals in step S2, it is determined in step S2 whether a shift command is output. When the shift command is output, the turbine rotation speed N at that time is stored as the shift start rotation speed NS, while the shift end rotation speed NE is calculated based on the vehicle speed and the type of shift (steps S3 and S4). .

Next, the controller 7 executes step S5 to change the amount of change in the throttle opening α per unit time,
That is, the throttle change rate Δα is calculated, and it is determined in step S6 whether or not the change rate Δα is larger than a predetermined value α0 (≈0). That is, it is determined whether or not the shift operation is based on a change in engine load.

When the controller 7 determines that the throttle change rate Δθ is larger than the predetermined value α0, the controller 7 proceeds to step S7 and determines whether or not the shift operation is an upshift, and determines that it is an upshift. If so, step S8 is executed to perform a pressure value calculation process according to type A described later, and the line pressure control signal is changed to a duty solenoid valve for line pressure control so that the pressure value calculated in step S9 is obtained. To 62.

Here, the outline of the calculation process of the pressure value will be described. As a basis for calculating the pressure value, the controller 7 calculates the pressure value as shown in the following equation with respect to the pressure value P on the right side.
A predetermined relational expression having a first term related to the turbine torque τT input to the speed change mechanism 5 and a second term related to the rate of change of the turbine rotation speed N on the left side is stored.

P = A (τT-B (NE-NS) / T) ... "(NE-NS) / T" in the second term of this relational expression.
Indicates that the value obtained by subtracting the shift start rotation speed NS from the shift end rotation speed NE is divided by the target shift time T. Note that A and B are coefficients that are changed according to the type of shift. That is, by designating the turbine torque τT, the shift start rotation speed NS, and the shift end rotation speed NE, the pressure value P for completing the shift operation in the target shift time T is automatically determined.

The above relational expression is derived as follows.

That is, assuming that the angular velocity of the output shaft 15 of the speed change mechanism 5 is ω, the input torque is τIN, and the torque capacity of the friction element 14 involved in the speed change operation is τCL, the angular acceleration of the output shaft 15 at the time of speed change. (Dω / d
t) is shown by the following equation.

Dω / dt = aτIN−bτCL ... On the other hand, the input rotational speed of the transmission mechanism 5 before shifting is NS,
Assuming that the input rotation speed NE after the gear shift is the time required for the gear shift operation, the angular acceleration (dω / dt) is approximated by the following equation.

Dω / dt≈ (NE-NS) / T Next, if the equation is modified and the angular acceleration is replaced by the equation,
The torque capacity τCL of the friction element 14 is approximated by the following relational expression.

ΤCL≈a / b (τIN-1 / a (NE-NS) / T) Therefore, since the torque capacity of the friction element 14 is proportional to the working oil pressure, the above relational expression can be easily derived. become.

Then, in the type A which shows the setting state of the pressure value at the time of shift-up shift based on the reduction of the engine load, the target shift time T is set as follows using the throttle change rate and the road surface gradient as parameters. There is. That is, with respect to the throttle change rate, as shown in FIG. 4, the target shift time T is set longer as the throttle change rate Δα increases. On the other hand, with respect to the road surface gradient, as shown in FIG. 5, the target shift time T is set to be longer as the road surface gradient θ in the traveling direction changes from an up state to a flat state to a down state. There is.

That is, in the type A, the controller 7 determines the target shift time T by applying the actual throttle change rate Δα to the map of FIG. 4 and the actual road surface gradient to the map of FIG. . Then, the target shift time T, the turbine torque τT, the shift end rotational speed NE, and the shift start rotational speed NS are substituted into the above relational expression to determine the pressure value P.

On the other hand, the controller 7 performs the above step S
When it is determined that it is not an upshift in 7,
In step S10, a pressure value calculation process according to type B is performed.

Also in the type B which shows the setting state of the pressure value at the time of the shift down shift based on the increase of the engine load, the target shift time T is set as follows with the throttle change rate and the road surface gradient as parameters. . That is, as shown in FIG. 6, the throttle change rate is set so that the target shift time T becomes shorter as the throttle change rate Δα increases. On the other hand, with respect to the road surface gradient, as shown in FIG. 7, the target shift time T is set to be shorter as the road surface gradient θ in the traveling direction changes from an up state to a flat state to a down state. There is.

That is, in the type B, the controller 7 determines the target shift time T by applying the actual throttle change rate Δα to the map of FIG. 6 and the actual road surface gradient θ to the map of FIG. To do. And
The target shift time T, the turbine torque τT, the shift end rotation speed NE, and the shift start rotation speed NS are substituted into the above relational expression to determine the pressure value P.

Further, the controller 7 executes the above step S
When it is determined in 6 that the throttle change rate Δα is not larger than the predetermined value α0, that is, when it is determined that the shift operation is not based on the change in the engine load, the process proceeds to step S11 and the type C is followed. The calculation process of the pressure value is performed.

In this type C, the target shift time T
As a constant value T 0 is set.

That is, the controller 7 determines that the target shift time
Constant value T as T After setting 0, at the target shift
Interval T, turbine torque τT, speed change end rotation speed NE, and speed change
The pressure value P is calculated by substituting the starting rotational speed NS into the above relational expression.
It will be decided.

The controller 7 executes the above step S
When it is determined in 2 that the gear shift command is not output, the process branches to step S12 to calculate a steady-state pressure value based on, for example, the throttle opening θ.

Next, the operation of this embodiment will be described.

That is, when the gear shifting operation is not based on the change of the throttle opening, the working hydraulic pressure is such that the gear shifting operation is completed within a certain gear shifting time corresponding to the turbine torque τT and the variation of the turbine speed N before and after the gear shifting. Will be obtained.

On the other hand, at the time of shift-up shift due to the decrease in engine load, the target shift time T becomes longer as the throttle change rate Δα increases, for example. Therefore, a shift operation with less shift shock is performed without excessively lengthening the shift time, and an uncomfortable feeling at the time of shift-up shifting in the half throttle state in which the accelerator pedal is returned to the half open state is appropriately prevented. .

Further, the target shift time T becomes longer as the road surface gradient θ changes from the up state to the down state via the flat state. As a result, the shift time is substantially constant, and the shift operation with less shock is performed.

On the other hand, at the time of shift-down shift due to an increase in engine load, the target shift time T becomes shorter as the throttle change rate Δα increases, for example. Therefore,
A gear shift operation with good acceleration response is performed without causing an extreme deterioration of gear shift shock.

Further, the target gear shift time T becomes shorter as the road surface gradient θ changes from an up state to a down state via a flat state. As a result, the shift time is substantially constant, and the shift operation with less shock is performed.

[0052]

As described above, according to the present invention, the operating oil pressure supplied to the friction element forming the power transmission path in the speed change mechanism at the time of speed change is related to the input torque of the speed change mechanism. Since it is set based on a predetermined relational expression consisting of the second term relating to the rate of change of the input speed, it is appropriate to complete the gear shifting operation in a short time without causing an excessive shock. Can be done.

Further, according to the first aspect of the present invention, at the time of shifting based on the change of the engine load, the second term relating to the change rate of the input speed in the above relational expression is corrected based on the change rate of the engine load. As a result, the setting state of the hydraulic pressure is changed so that the shift time corresponds to the rate of change of the engine load.Therefore, when shifting down due to an increase in the engine load, the shift time is shortened to reduce the acceleration response. The shift operation with good performance is performed, and when shifting up due to the reduction of engine load, the shift time is lengthened to perform the shift operation with almost no shift shock.
It is possible to perform an appropriate shift operation according to the request.

Further, according to the second aspect of the invention, at the time of shift-down shift accompanying the increase of the engine load, the setting state of the operating hydraulic pressure is changed such that the shift time becomes shorter as the increase rate of the engine load increases. Therefore, it is possible to perform a gear shift operation with good acceleration response without causing an extreme deterioration of gear shift shock.

Further, according to the third aspect of the present invention, at the time of shift-up shifting accompanying a decrease in engine load, the setting state of the operating hydraulic pressure is changed so that the shift time becomes longer as the rate of decrease in engine load increases. Thus, it becomes possible to perform the gear shifting operation with less gear shifting shock without lengthening the gear shifting time.

Further, according to the fourth aspect of the invention, in the second term relating to the rate of change of the input rotational speed in the relational expression for setting the hydraulic pressure, the difference between the input rotational speeds before and after the gear shift is gradually divided by the time therebetween. Since the element is provided and the time is corrected based on the rate of change of the engine load, an appropriate hydraulic pressure corresponding to the desired shift time can be obtained.

On the other hand, according to the fifth aspect of the invention, the second aspect relating to the rate of change of the input rotational speed in the relational expression for setting the hydraulic pressure is set.
By correcting the term based on the road surface gradient in the traveling direction of the vehicle, the setting state of the hydraulic pressure is changed so that the shift time corresponding to the road surface gradient is obtained.
The shift operation can be more appropriately performed so as to be completed in a short time without causing an excessive shock.

[Brief description of drawings]

FIG. 1 is a control system diagram of a power plant having an automatic transmission according to an embodiment.

FIG. 2 is a block diagram showing a line pressure control portion in a hydraulic control circuit.

FIG. 3 is a flowchart showing a line pressure control according to the embodiment.

FIG. 4 is an explanatory diagram of a map used for the control.

FIG. 5 is an explanatory diagram of a map used for the control.

FIG. 6 is an explanatory diagram of a map used for the control.

FIG. 7 is an explanatory diagram of a map used for the control.

[Explanation of symbols]

 1 Automatic Transmission 5 Transmission Mechanism 7 Controller 9 Throttle Opening Sensor 13 Road Surface Gradient Sensor 14 Friction Element

Claims (5)

[Claims] 1. A hydraulic pressure during a gear shift supplied to a friction element forming a power transmission path in a speed change mechanism is defined by a first item relating to an input torque of the speed change mechanism and a rate of change of an input rotational speed of the speed change mechanism. An operating oil pressure setting means for setting based on a predetermined relational expression consisting of the related second term, an engine load detecting means for detecting an engine load, and a gear shift detecting means for detecting a shift based on a change in the engine load. By correcting the second term in the above relational expression based on the change rate of the engine load, the setting state of the working oil pressure by the working oil pressure setting means is changed so that the shift time corresponding to the engine load change rate is obtained. A hydraulic control device for an automatic transmission, comprising: operating hydraulic pressure setting state changing means. 2. The hydraulic pressure at the time of shifting supplied to the friction element forming the power transmission path in the speed change mechanism is set to the first term related to the input torque of the speed change mechanism and the change rate of the input speed of the speed change mechanism. The operating oil pressure setting means set based on a predetermined relational expression consisting of the related second term, the engine load detecting means for detecting the engine load, and the engine load detecting means at the time of downshifting due to an increase in the engine load. By correcting the second term in the above relational expression based on the rate of change of the engine load detected by, the operating hydraulic pressure is set by the operating hydraulic pressure setting means such that the shift time becomes shorter as the increasing rate of the engine load increases. A hydraulic control device for an automatic transmission, comprising: an operating hydraulic pressure setting state changing means for changing the state. 3. The hydraulic pressure at the time of shifting supplied to the friction element forming the power transmission path in the speed change mechanism is set to the first term related to the input torque of the speed change mechanism and the rate of change of the input speed of the speed change mechanism. The operating oil pressure setting means set based on a predetermined relational expression consisting of the related second term, the engine load detecting means for detecting the engine load, and the engine load detecting means at the time of a shift-up shift accompanying a decrease in the engine load. By correcting the second term in the above relational expression based on the rate of change of the engine load detected by the above, the hydraulic pressure is set by the hydraulic pressure setting means so that the shift time becomes longer as the rate of decrease of the engine load increases. A hydraulic control device for an automatic transmission, comprising: an operating hydraulic pressure setting state changing means for changing the state. 4. The second term relating to the rate of change of the input rotational speed in the relational expression for setting the operating hydraulic pressure has an element in which the difference between the input rotational speeds before and after shifting is divided by the time between them, and 4. The hydraulic control device for an automatic transmission according to claim 1, wherein the setting state changing means corrects the time based on the rate of change of the engine load. 5. A hydraulic pressure during shifting, which is supplied to a friction element forming a power transmission path in the speed change mechanism, is set to a first item related to an input torque of the speed change mechanism and a change rate of an input rotational speed of the speed change mechanism. A hydraulic pressure setting means that is set based on a predetermined relational expression consisting of the related second term, a road surface gradient detecting means that detects a road surface gradient in the traveling direction of the vehicle, and a road surface gradient detected by the detecting means. By correcting the second term in the above relational expression based on the above, there is provided an operating hydraulic pressure setting state changing means for changing the setting state of the operating hydraulic pressure by the operating hydraulic pressure setting means so that the shift time corresponds to the road surface gradient. A hydraulic control device for an automatic transmission, characterized in that