JP3224611B2 - Hydraulic control device for automatic transmission - Google Patents

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 a motor vehicle, and more particularly to a hydraulic control device for an automatic transmission in which a fastening force of a friction element is controlled by a hydraulic pressure.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile combines a torque converter to which an engine output is input and a transmission mechanism driven by the output of the converter, and connects a power transmission path of the transmission mechanism to a clutch or the like. The automatic transmission is configured such that the gears are switched by a selective operation of a plurality of friction elements such as a brake to automatically shift to a predetermined gear position. Is controlled by the
In this case, if the operating oil pressure supplied to the friction element that is engaged or released at the time of shifting is low, the friction element is unnecessarily slipped, and the shift time is unnecessarily long, resulting in a poor shift feeling. Conversely, if the operating oil pressure supplied to the friction element is high, the shift time becomes too short and a large shift shock occurs.

Therefore, it has been considered to set the operating oil pressure at the time of shifting supplied to the friction element so that the shifting operation is completed in a predetermined target time. For example, Special Publication 5
Japanese Patent Application Laid-Open No. 8-501277 discloses that the operating oil pressure of a friction element at the time of shifting is changed so that the shifting operation is completed in a fixed 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 focuses on the fact that the engine speed is increased or decelerated so that the engine speed becomes a speed corresponding to the output speed of the speed change mechanism during shifting, without causing excessive shifting shock. The shifting operation can be completed in a short time.

[0004]

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

[0005] That is, in this type of automatic transmission, a shift operation may be performed based on a change in engine load. In this case, a shift operation different from a normal operation is required. In other words, during a downshift with an increase in the engine load, a shift operation with good responsiveness is required even if a slight shock occurs, while in a shift upshift with a decrease in the engine load, the responsiveness is high. A shift operation with less shock is required even at the expense of. In this case, if the operating oil pressure of the friction element is set so that the shift time is constant, not only does the shift time become too long at the time of shifting accompanying an increase in engine load, so that a good feeling of acceleration cannot be obtained, At the time of shift-up shifting with a decrease in engine load, on the contrary, the shifting time is too short and a large shifting shock occurs.

In addition, at the time of upshifting in a half throttle state in which the accelerator pedal is returned to a half open state,
Even though the driver expects a feeling of deceleration, a shock is unexpectedly generated and the driver feels discomfort.

[0007] On the other hand, the following inconvenience also occurs depending on the road surface gradient in the traveling direction of the vehicle. That is, for example, at the time of downshifting, the friction element engaged in the high gear is released, and the transmission mechanism becomes neutral,
The input rotation speed or the rotation speed of the transmission mechanism increases. Then, 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 this time, a transient vibration occurs due to the torsional rigidity of the vehicle body. The magnitude of the vibration depends on the relative rotational acceleration before and after the one-way clutch. In other words, the larger the relative rotational acceleration is, the stronger the vibration becomes. In this case, in the uphill state, the rotational speed on the output side of the one-way clutch is reduced 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. The vibration becomes relatively short compared to the road, and the vibration becomes strong, which may cause the driver to feel extreme discomfort. Conversely, in the down state, the rotational speed on the output side of the one-way clutch is accelerated due to the gravitational acceleration, so that the relative rotational acceleration before and after the one-way clutch becomes small, and the shift time is relatively shorter than on a flat road. It becomes longer and the shift feeling becomes worse. And the opposite
At the time of shift-up shifting,
When the friction element is released and the transmission mechanism becomes neutral
In addition, the input rotation speed decreases and the road gradient decreases.
In, the rotation speed on the output side is accelerated and the relative rotation acceleration is large.
Shift time is relatively short compared to a flat road
And the above vibrations become stronger.
Rotation speed also decreases, and the relative rotation acceleration decreases.
As a result, the shift time is relatively longer than
The quick feeling deteriorates.

The present invention addresses the above-described problem in an automatic transmission in which the engagement force of a friction element is controlled by oil pressure, and appropriately sets the operating oil pressure supplied to the friction element during gear shifting. 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 a first invention) supplies a hydraulic element to a friction element forming a power transmission path in a transmission mechanism. Operating hydraulic pressure at the time of shifting
The first term relating to the input torque of the mechanism and the input of the transmission mechanism
A predetermined relation comprising a second term relating to the rate of change of the rotational speed;
Operating oil pressure setting means for setting based on the equation ; engine load detecting means for detecting the engine load;
The above engine load detection
Based on the rate of change of the engine load detected by the
By correcting the second term in the relational expression, the engine
Operating oil pressure setting state changing means for changing the setting state of the operating oil pressure by the operating oil pressure setting means so that the shift time becomes longer as the load reduction rate increases .

The invention of claim 2 of the present application (hereinafter referred to as the second invention)
The present invention relates to a hydraulic control device for an automatic transmission, comprising: a hydraulic pressure control device for an automatic transmission, comprising: a working oil pressure setting means for setting, based on a predetermined relational expression and a second term related to the input speed of the change rate of the mechanism, an engine load detecting means for detecting an engine load, detected by the engine load detecting means Be done
Based on the rate of change of the engine load,
By correcting the two terms, the engine load is reduced.
During shift upshifts, the rate of decrease in engine load is large.
Increase the engine load so that the longer the shifting time
During a downshift due to the
The operating oil pressure setting state changing means for changing the setting state of the operating oil pressure by the operating oil pressure setting means is provided so that the gear shift time becomes shorter as the value of the hydraulic pressure becomes larger .

[0011]

[0012]

Further, the invention of claim 3 of the present application (hereinafter referred to as the
According to a third aspect of the present invention , the hydraulic control device for an automatic transmission according to the first and second aspects of the present invention includes a second term related to the rate of change of the input rotation speed in the relational expression for setting the operating oil pressure, and a second term related to before and after shifting , An element obtained by subtracting the difference of the input rotation speeds in the time period between them is provided, and the operating oil pressure setting state changing means is configured to correct the time period based on the change rate of the engine load.

[0014]

The invention of claim 4 of the present application (hereinafter referred to as “ fourth invention” )
The present invention relates to a hydraulic control device for an automatic transmission, comprising: a hydraulic pressure control device for an automatic transmission, comprising: Operating hydraulic pressure setting means for setting based on a predetermined relational expression comprising a second term relating to the rate of change of the input rotation speed of the mechanism, road surface gradient detecting means for detecting a road surface gradient in the traveling direction of the vehicle, and an engine Detect load
The engine load detection means and the system
Detected by the road surface gradient detecting means
Road surface gradient and the engine load
Based on the engine load change rate,
By correcting the two terms, the road surface gradient increases in the down direction
Shift time
The operating oil pressure setting state changing means for changing the setting state of the operating oil pressure by the operating oil pressure setting means is provided so that the length becomes longer .

[0016]

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

[0017]

That is, in any of the first to third aspects of the present invention , the operating oil pressure supplied to the friction element forming the power transmission path at the time of shifting is determined by the first term related to the input torque of the transmission mechanism and the input rotation speed. Is set based on a predetermined relational expression consisting of the second term relating to the rate of change of the gear ratio, so that the shift operation can be appropriately performed so as to be completed in a short time without causing excessive shock. Can be.

In particular, according to the first aspect, the engine load is low.
At the time of shift-up shifting accompanying the
Hydraulic oil so that the shift time becomes longer as the rate of decrease
Since the pressure setting state is changed, it is necessary to lengthen the shifting time.
Gear shifting operation with less shifting shock without
It becomes possible.

Further , according to the second invention, the first invention and the first invention are combined.
Similarly, at the time of upshifting due to a decrease in engine load
, The higher the rate of decrease in engine load,
The setting state of the hydraulic pressure is changed so that the
The shift shock can be reduced without lengthening the shift time.
Gear shift operation can be performed, and at the time of downshifting with an increase in engine load,
Since the setting state of the operating oil pressure is changed so that the shift time becomes shorter as the rate of increase of the engine load becomes larger, it is possible to perform a shift operation with good acceleration response without causing extreme deterioration of the shift shock. Become.

[0021]

Further, according to the third aspect of the present invention , the difference between the input rotation speed before and after the speed change is gradually reduced to the second term relating to the change rate of the input rotation speed in the relational expression for setting the operating oil pressure. Since the elements are provided and the time is corrected based on the rate of change in the engine load, an appropriate operating oil pressure corresponding to a desired shift time can be obtained.

[0023]

[0024] On the other hand, according to the fourth invention, the first invention is combined with the first invention.
Similarly, at the time of upshifting due to a decrease in engine load
, The higher the rate of decrease in engine load,
If the setting state of the hydraulic pressure is changed so that the interval becomes longer,
In both cases, the larger the gradient in the down direction, the greater the gradient of the road surface.
The setting state of the hydraulic pressure is changed so that the gear shifting time becomes longer.
To reduce engine load while traveling on a slope.
The gear shifting time when shifting up
To perform shifting operation with less shifting shock
Becomes possible.

[0025]

Embodiments of the present invention will be described below.

As shown in FIG . 1, an automatic transmission 3 constituting 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,
A hydraulic control circuit 6 for controlling supply / discharge of line pressure supplied to a plurality of friction elements (not shown) for switching a power transmission path of the transmission mechanism 5.

[0027] Then, the above-described power plant 2 is provided with a controller 7 that performs various controls, the controller 7, the throttle opening degree detecting the opening degree of the throttle valve 8, which is deployed in an intake passage of the engine 1 A signal from a sensor 9, a signal from a vehicle speed sensor 10 for detecting a vehicle speed of the vehicle, and a turbine speed sensor 1 for detecting an output speed (turbine speed) of the torque converter 5.
1, a signal from a torque sensor 12 for detecting an output torque of the torque converter 4, and a signal from a road surface gradient sensor 13 for detecting a road surface gradient in the traveling direction of the vehicle. The shift control by the shift solenoid valves 61 to 61 provided in the circuit 6 and the line pressure control by the duty solenoid valve 62 similarly provided in the hydraulic control circuit 6 are performed.

[0028] Here, the configuration of a portion related to the line pressure control in the hydraulic control circuit 6 schematically.

[0029] That is, as shown in FIG. 2, with regulator valve 64 for pressurizing regulates the working oil pressure between the oil pump 63 and the friction element 14 is interposed, the control pressure is above the duty of the regulator valve 64 By performing duty control by the solenoid valve 62, the line pressure on the downstream side of the regulator valve 64 is adjusted to a pressure corresponding to the line pressure control signal output from the controller 7.

Next, when describing a line pressure control which is a characteristic part of this embodiment, control the line pressure is specifically carried out as follows according to the flowchart of FIG.

[0031] That is, the controller 7 step S1
After reading various signals, it is determined in step S2 whether a shift command has been output. When the shift command is output, the turbine speed N at that point is stored as the shift start speed NS, while the shift end speed NE is calculated based on the vehicle speed and the type of shift (steps S3 and S4). .

[0032] Then, the controller 7 is the amount of change per unit time of the throttle opening α executes step S5,
That is, the throttle change rate △ α is calculated, and it is determined in step S6 whether the change rate △ α 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 the engine load.

When the controller 7 determines that the throttle change rate .DELTA..theta. Is larger than the predetermined value .alpha.0, the process proceeds to step S7 to determine whether the shift operation is an upshift, and determines that the upshift is performed. When this is done, step S8 is executed to calculate the pressure value according to the type A described later, and the line pressure control signal is changed so that the pressure value calculated in step S9 is obtained. 62.

[0034] Here, an outline of calculation of the pressure value, as a basis for calculating the pressure values to the controller 7, as shown in the following equation, with respect to the right side of the pressure value P, the speed change mechanism 5 A predetermined relational expression having, on the left side, a first term related to the turbine torque τT and a second term related to the rate of change of the turbine speed N 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 rotational speed NS from the shift end rotational speed NE is decremented by the target shift time T. A and B are coefficients that are changed according to the type of shift. That is, if the turbine torque τT, the shift start rotational speed NS, and the shift end rotational speed NE are designated, 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.

[0037] That is, the angular velocity of the output shaft 15 of the speed change mechanism 5 and omega, the input torque as TauIN, when the torque capacity of the friction elements 14 involved in the gear shift operation will be assumed TauCL, angular acceleration of the output shaft 15 during the shift (Dω / d
t) is represented by the following equation.

[0038] dω / dt = aτIN-bτCL ...... On the other hand, the input rotation speed before shifting in the speed change mechanism 5 NS,
Assuming that the time required for the shift operation is T as the input rotational speed NE after the shift, the angular acceleration (dω / dt) is approximated by the following equation.

[0039] dω / dt ≒ (NE-NS ) / T ...... Then, by replacing the angular acceleration in the formula by modifying the formula,
The torque capacity τCL of the friction element 14 is approximated by the following relational expression.

[0040] τCL ≒ a / b (τIN- 1 / a (NE-NS) / T) ...... Thus, the torque capacity of the friction element 14 is proportional to the hydraulic pressure, that the above equation is easily derived become.

In the type A indicating the setting state of the pressure value at the time of the shift-up shift based on the decrease 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. I have. That is, as shown in FIG. 4, the target shift time T is set to be longer as the throttle change rate △ α increases. On the other hand, with respect to the road gradient, as shown in FIG. 5, the target shift time T is set to be longer as the road gradient θ in the traveling direction changes from an up state to a down state through a flat state. I have.

[0042] That is, the controller 7 is in the type A, the actual throttle change rate △ the α fit in the map of FIG. 4, also determines a target shift time T by fitting the road surface gradient of reality map of FIG. 5 . Then, the pressure value P is determined by substituting the target shift time T, the turbine torque τT, the shift end rotational speed NE, and the shift start rotational speed NS into the above relational expression.

[0043] On the other hand, the controller 7, the above-mentioned step S
If it is determined in step 7 that it is not an upshift,
The process proceeds to step S10 to perform a pressure value calculation process according to type B.

In the type B indicating the setting state of the pressure value at the time of downshifting based on the increase 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. . That is, as shown in FIG. 6, the target shift time T 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 gradient, as shown in FIG. 7, the target shift time T is set such that the target shift time T becomes shorter as the road gradient θ in the traveling direction changes from an up state to a down state through a flat state. I have.

[0045] That is, the controller 7 is in the type B, determines a target shift time T by actual throttle change rate △ the α fit to the map of FIG. 6, also fits the actual road surface gradient θ in the map of FIG. 7 I do. And
The target shift time T, turbine torque τT, shift end rotational speed NE, and shift start rotational speed NS are substituted into the above relational expression to determine the pressure value P.

Further , the controller 7 executes the above-described step S
When it is determined in Step 6 that the throttle change rate △ α is not larger than the predetermined value α0, that is, when it is determined that the speed change operation is not based on a change in the engine load, the process proceeds to Step S11 and follows Type C. The pressure value is calculated.

In this type C, the target shift time T
Is set to a fixed value T0.

[0048] That is, the controller 7, after setting the predetermined value T0 as the target shift time T, the target shift time T and the turbine torque τT a shift-end speed NE and the shift start rotation speed NS of the above equation The pressure value P is determined by substitution.

It should be noted that the controller 7 executes the above-described step S
If it is determined in step 2 that the gearshift command has not been output, the flow 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.

[0051] That is, when the shift operation is not based on the change of the throttle opening degree, the working oil pressure such that the shift operation in response to the change of the turbine speed N before and after shifting the turbine torque τT at constant shifting time is completed Is obtained.

[0052] In contrast, at the time of shift-up due to the reduction in the engine load, for example, the target shift time T as the throttle rate of change △ alpha is increased becomes long. Therefore, the shift operation with less shift shock is performed without unnecessarily lengthening the shift time, and the uncomfortable feeling during the shift-up shift in the half throttle state in which the accelerator pedal is returned to the half-open state is appropriately prevented. .

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

On the other hand, at the time of shift-down with increasing engine load, for example, the target shift time T as the throttle rate of change △ alpha increases becomes short. Therefore,
A shift operation with good acceleration response is performed without causing extreme deterioration of the shift shock.

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

[0056]

[0057]

As described above , according to the first to third aspects of the present invention , the operating oil pressure supplied to the friction element forming the power transmission path at the time of gear shifting is changed according to the input torque of the transmission mechanism. Since the setting is made based on a predetermined relational expression consisting of one term and the second term related to the rate of change of the input rotation speed, the shifting operation can be completed in a short time without causing excessive shock. Can be performed appropriately.

In particular, according to the first aspect, the engine load is low.
At the time of shift-up shifting accompanying the
Hydraulic oil so that the shift time becomes longer as the rate of decrease
Since the pressure setting state is changed, it is necessary to lengthen the shifting time.
Gear shifting operation with less shifting shock without
It becomes possible.

Further , according to the second invention, the first invention and
Similarly, at the time of upshifting due to a decrease in engine load
, The higher the rate of decrease in engine load,
The setting state of the hydraulic pressure is changed so that the
The shift shock can be reduced without lengthening the shift time.
Gear shift operation can be performed, and at the time of downshifting with an increase in engine load,
Since the setting state of the operating oil pressure is changed so that the shift time becomes shorter as the rate of increase of the engine load becomes larger, it is possible to perform a shift operation with good acceleration response without causing extreme deterioration of the shift shock. Become.

[0060]

Further, according to the third aspect of the present invention , the difference between the input rotation speed before and after the shift is gradually reduced to the second term related to the change rate of the input rotation speed in the relational expression for setting the operating oil pressure. Since the elements are provided and the time is corrected based on the rate of change in the engine load, an appropriate operating oil pressure corresponding to a desired shift time can be obtained.

[0062]

According to the fourth invention, the first invention
As in the case of the above, upshifting due to a decrease in engine load
In some cases, the higher the rate of decrease in engine load, the
The setting state of the hydraulic pressure is changed so that the time becomes longer
At the same time, the gradient of the road surface
The setting state of the hydraulic pressure is changed so that the gear shifting time becomes longer
The engine load during traveling on a slope
Shift up time when shifting up
Gear shifting operation with less shifting shock.
It becomes possible.

[Brief description of the 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 illustrating a line pressure control portion in the hydraulic control circuit.

FIG. 3 is a flowchart illustrating 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]

 DESCRIPTION OF SYMBOLS 1 Automatic transmission 5 Transmission mechanism 7 Controller 9 Throttle opening degree sensor 13 Road surface gradient sensor 14 Friction element

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (4)

(57) [Claims] An operating hydraulic pressure supplied to a friction element forming a power transmission path in a transmission mechanism during a gear shift is transmitted to the transmission.
The first term relating to the input torque of the transmission and the input rotation of the transmission mechanism.
A predetermined relational expression consisting of the second term related to the rate of change of the number of turns
Hydraulic pressure setting means to be set based on
Engine load detecting means for detecting the
The above engine load detection during shift upshift
Based on the rate of change of the engine load detected by the means
By correcting the second term in the relational expression, the engine
Operating oil pressure setting state changing means for changing the setting state of the operating oil pressure by the operating oil pressure setting means so that the shift time becomes longer as the load reduction rate increases. Hydraulic control device for automatic transmission. 2. The method according to claim 1, wherein the operation hydraulic pressure supplied to a friction element forming a power transmission path in the speed change mechanism is controlled by a change in an input speed of the speed change mechanism and a change rate of an input rotation speed of the speed change mechanism. An operating oil pressure setting means for setting based on a predetermined relational expression comprising the related second term, an engine load detecting means for detecting an engine load, and an engine load detecting means.
Based on the rate of change of the engine load detected by the
By correcting the second term in the relational expression, the engine
During an upshift with a decrease in engine load, the engine
The higher the load reduction rate, the longer the shift time,
During a downshift with an increase in engine load,
The higher the engine load increase rate, the shorter the shift time
Thus, a hydraulic pressure control device for an automatic transmission is provided with a hydraulic pressure setting state changing means for changing the setting state of the hydraulic pressure by the hydraulic pressure setting means. The second term relating to the rate of change of the input rotational speed in the relational expression for setting the operating hydraulic pressure includes an element obtained by subtracting the difference between the input rotational speeds before and after the shift by the time between the input rotational speeds. 3. The hydraulic control device for an automatic transmission according to claim 1, wherein the setting state changing means corrects the time based on a change rate of the engine load. 4. An operation hydraulic pressure supplied to a friction element forming a power transmission path in a speed change mechanism during a speed change is determined by a first term related to an input torque of the speed change mechanism and a rate of change of an input rotation speed of the speed change mechanism. a working oil pressure setting means for setting, based on a predetermined relational expression and a second term related, and the road surface gradient detecting means for detecting a traveling direction of the road surface gradient of the vehicle, ene
Engine load detecting means for detecting a gin load, and an engine
When shifting up due to a decrease in load,
The road surface gradient detected by the detecting means and the engine load detection
Based on the rate of change of the engine load detected by the means
By correcting the second term in the above relational expression,
The greater the distribution in the downward direction, the lower the engine load reduction rate
A hydraulic pressure control device for an automatic transmission, comprising: an operating oil pressure setting state changing means for changing a setting state of an operating oil pressure by the operating oil pressure setting means so that a shift time becomes longer as the shift time increases .