JPH0478364A - Shift control device for automatic transmission for vehicles - Google Patents

Abstract

PURPOSE:To suppress speed change shock and perform the optimum control of line pressure during normal operation by setting accumulator back pressure at the time of judging speed change operation and line pressure at the time of judging non-operation of speed change according to the operating state. CONSTITUTION:During speed change operation, a control signal corresponding to accumulator back pressure is outputted to a line pressure solenoid valve 17 to change control pressure from the line pressure solenoid valve 17, so that accumulator back pressure corresponding to the operating state is supplied to accumulators 22A-22E from an accumulator control valve 19. During non- operation of speed change, a control signal corresponding to line pressure is outputted to the line pressure solenoid valve 17, and its control pressure is changed and applied to a pressure control valve 20 through a pressure modifier valve 18. The pressure delivered from an oil pump 16 is thereby controlled to be the set line pressure by the pressure control valve 20 and a feedback accumulator piston 21.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a shift control device for an automatic transmission for a vehicle.

<Prior art> A shift control device for an automatic transmission for a vehicle is equipped with an automatic transmission having a planetary gear device, and the shift operation involves releasing one of the shift elements (clutch) and engaging the other. This is done by The engagement and disengagement of the transmission elements is determined by the driving conditions of the vehicle, such as vehicle speed and throttle valve opening.

Here, hydraulic fluid is supplied to each gear shift element via a shift solenoid valve for supplying hydraulic fluid based on a control signal from a control device based on vehicle operating conditions such as vehicle speed and throttle valve opening, and the gear shift operation is performed. It will be done.

In addition, an accumulator is provided to control the hydraulic pressure supplied to the shift element in order to suppress shift shock during shift operation, and this accumulator suppresses the rise of the hydraulic pressure in accordance with the supplied accumulator back pressure. This is designed to reduce gear shift shock.

Here, the line pressure and accumulation back pressure supplied to the shift solenoid valve are changed and set by control pressure from a single line pressure solenoid valve, and the line pressure solenoid valve is driven and controlled by a control device. Vary the control pressure.

<Problems to be Solved by the Invention> In the past, the line pressure solenoid valve was always driven and controlled based on the accumulation back pressure, with emphasis on alleviating shift shock. Along with this, the line pressure also changes.

However, during steady operation (when not shifting), it is sufficient to ensure line pressure to maintain the gripping force of the gear shifting elements, such as the clutch.If the line pressure is changed according to the accumulation back pressure, the oil pump The problem is that it is only possible to perform detailed control such as setting the minimum necessary line pressure according to the input torque in order to minimize the load.

SUMMARY OF THE INVENTION In view of these circumstances, it is an object of the present invention to provide a shift control device that can optimally control line pressure during steady operation while suppressing shift shock.

Means for Solving the Problems> Therefore, as shown in FIG.
A, and these speed change elements Δ1 to A.

Working pressure supply means 81-B for supplying working pressure to.

, a line pressure supply means C for supplying line pressure to these working pressure supply means 81 to B, and the said working pressure supply means 31 to B. a shift operation means for operating the shift element according to the target shift speed, and an operating pressure control means for variably controlling the rise of the operating pressure supplied to the shift element according to the accumulation back pressure.

, a line pressure control means F for variably controlling the line pressure, a 7-unit back pressure control means G for variably controlling the accumulation back pressure, and the accumulation back pressure control means G and the line pressure control means F. a control signal output means H that outputs the same control signal to the control signal, and a shift operation determination means I that determines whether or not a shift operation is in progress; The line pressure setting means J sets the line pressure according to the operating state when it is determined that the non-shift operation is in progress, and the line pressure setting means J sets the line pressure according to the operating state when it is determined that the non-shift operation is in progress. A drive control means for controlling the drive of the control signal output means H accordingly is provided.

<Operation> In this way, during a gear shift operation, the accumulation back pressure is preferentially variably controlled based on the control signal corresponding to the set accumulation back pressure, thereby suppressing shift shock. On the other hand, during non-shift operation, line pressure is preferentially controlled based on a control signal corresponding to the set line pressure to ensure optimal line pressure.

<Example> An example of the present invention will be described below based on FIGS. 2 to 7.

First, the automatic transmission for a vehicle will be explained based on FIG. 3. The torque converter 1 is provided with a pump impeller IA, a turbine impeller IB, and a stator IC.

The transmission 2 also includes a planetary gear and a device 2A.
, front clutch 2B, rear clutch 2C, brake band 2D, low & reverse brake 2E, one-way clutch 2F.

A parking ball 2G is provided.

For example, when shifting from 1st to 2nd gear in D range, one-way clutch 2F is released and brake band 2D
Speed change is achieved by coupling the two. In this way, the engine output is transmitted via the torque converter 1 and the transmission 2 to the drive wheels of the vehicle.

Here, each of the above-mentioned speed change elements includes a speed change control device 11 to be described later.
Hydraulic oil is supplied through shift solenoid valves 2A to 12E, which serve as operating pressure supply means, to perform a speed change operation.

As shown in FIG. 2, the speed change control device 11 receives a throttle valve opening detection signal from a throttle sensor 13 and a vehicle speed detection signal from a vehicle speed sensor 14.

Further, a line pressure passage 15 is provided for supplying oil to each of the shift solenoid valves 12A to 12E and the torque converter I, and the line pressure passage 15 is supplied with line pressure oil from an oil pump 16 serving as a line pressure supply means. be done. Further, a control signal is inputted from the transmission control device 11 to the line pressure solenoid valve 17 serving as a control signal output means, and the line pressure solenoid valve 17 pressure-modifies the control pressure according to the control signal as shown in FIG. 18 and an accumulation control valve 19 as an accumulation back pressure control means.

The pressure modifier valve 18 applies a signal pressure corresponding to the control pressure to the pressure regulator valve 20 in order to adjust the line pressure to the optimum pressure according to the operating conditions. The pressure regulator valve 20 outputs a signal pressure corresponding to the actual line pressure from the line pressure passage 15 and the signal pressure to the feedback accumulation piston 21, and adjusts the discharge pressure of the oil pump 16 to the optimal target line pressure. control. Therefore, the pressure modifier valve 18, the pressure regulator valve 20, and the feedback accumulation piston 21 constitute line pressure control means.

The accumulation control valve 19 is configured to reduce the accumulation back pressure to an optimal pressure depending on the operating condition.
Accumulator back pressure corresponding to the control pressure is applied to the accumulators 22A to 22E as operating pressure control means. Accumulators 22A to 22E are connected to shift solenoid valves 12A to 12E to respective transmission elements 23A to 23E.
The rise of the hydraulic pressure supplied to the pump is controlled by changing it according to the accumulation back pressure.

The speed change control device 11 operates according to the flowchart shown in FIG. 5, and controls line pressure and accumulation back pressure.

Here, the shift control device 11 constitutes a shift operation means, a shift operation determination means, a line pressure setting means, an accumulation back pressure setting means, and a drive restriction means.

Next, the operation will be explained according to the flowchart shown in FIG.

First, to explain the shift control, the presence or absence of a shift is determined from a shift map based on detection signals from the throttle sensor 13 and vehicle speed sensor 14, and when it is determined that a shift is necessary, the shift solenoid valves 12A to 12E are driven and controlled to achieve the target. Each gear change element is connected and released according to the shift stage, and the gear change operation is performed automatically.

During this control, a routine shown in the flowchart of FIG. 5 is executed.

That is, in Sl, it is determined whether or not a gear shift operation is currently being performed;
If YES, proceed to S2; if NO, proceed to S4.

In S2, the accumulation back pressure is set in proportion to the original pressure set according to the throttle opening.

In S3, the duty ratio is searched from the map based on the set accumulation back pressure. This duty ratio (on-duty ratio) is set to increase as the accumulated back pressure increases, as shown in FIG.

On the other hand, during non-shift operation (normal operation), the line pressure is set in accordance with the operating state in S4. Specifically, the line pressure is set approximately proportional to the vehicle speed during engine braking, and is set by multiplying the input torque by a constant during non-engine braking.

In S5, the duty ratio is searched from the map based on the set line pressure. As shown by the solid line in FIG. 7, this duty ratio is set to a constant value below a predetermined line pressure, and is set to increase as the line pressure increases when the line pressure exceeds a predetermined line pressure. Furthermore, the seventh
As shown by the line in the figure, even if the line pressure is below a predetermined line pressure, the duty ratio may be changed and set according to the line pressure.

In S6, a control signal corresponding to the duty ratio set in S3 or S5 is sent to the line pressure trenoid valve 1.
Output to 7.

As a result, during a gear shift operation, a control signal corresponding to the accumulation back pressure is output to the line pressure solenoid valve 17, and the control pressure from the line pressure solenoid valve I7 changes, so that the accumulator 22A to Accumulation back pressure is supplied to 22E according to the operating state.

Therefore, the rise of the operating pressure supplied to the shift elements 23A to 23E by the accumulators 22A to 22E is suppressed, and shift shock can be optimally suppressed depending on the operating state.

On the other hand, during non-shift operation, a control signal corresponding to the line pressure is output to the line pressure solenoid valve 17, and the control pressure changes and is applied to the pressure control valve 20 via the vibration modifier valve 18. Thereby, the pressure discharged from the oil pump 16 is controlled by the pressure control valve 20 and the feedback accumulation piston 2I so that it becomes the set line pressure. However, during steady operation (
Since the line pressure (during non-shift operation) can be optimally set to the pressure that grips the clutch (shift element) according to the driving condition, drive loss of the oil pump 16 can be suppressed and fuel efficiency can be improved.

Here, there will be no problem if the line pressure changes in response to changes in the accumulator back pressure during a gear shift operation, or if the line pressure during a gear shift operation is set higher than the line pressure during a non-shift operation.

<Effects of the Invention> As explained above, the present invention preferentially controls the accumulation back pressure according to the set accumulation back pressure, while
Since the line pressure is controlled preferentially according to the set line pressure during non-shift operation, it is possible to secure the optimum line pressure while suppressing shift shock, thereby improving fuel efficiency.

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to claims of the present invention, Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is a block diagram of the automatic transmission same as above, and Fig. 4 is a hydraulic circuit diagram of essential parts of same as above. , FIG. 5 is a flowchart of the same as above, and FIGS. 6 and 7 are diagrams for explaining the operation of the same. 1... Torque converter 2... Transmission 11... Speed change control device 12A to 12E.
...Shift solenoid valve I6...Oil pump 17...Line pressure solenoid valve 18...
Pressure modifier valve 19...Accumulation control valve 20...Pressure regulator valve 21...Feedback accumulation piston 228-22E...Accumulator patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Sasa
Fujio Shima Figure 6 Figure 7 F1, To-no J

Claims (1)

[Claims] A pressure-responsive transmission element operated by operating pressure to perform a gear shifting operation, an operating pressure supply means for supplying operating pressure to these transmission elements, a line pressure supply means for supplying line pressure to these operating pressure supply means, a shift operation means for operating the operating pressure supply means in accordance with a target shift speed; an operating pressure control means for variably controlling the rise of the operating pressure supplied to the shift element in accordance with the accumulation back pressure; and a variable control means for controlling the line pressure. a line pressure control means for controlling, an accumulation back pressure control means for variably controlling the accumulation back pressure, and a control signal output means for outputting the same control signal to the accumulation back pressure control means and the line pressure control means;
A shift control device for an automatic transmission for a vehicle, comprising: a shift operation determining means for determining whether or not a shift operation is in progress; a setting means, a line pressure setting means for setting the line pressure according to the operating state when it is determined that a non-shift operation is being performed, and driving control of the control signal output means according to the set line pressure or accumulation back pressure. A speed change control device for an automatic transmission for a vehicle, comprising: a drive control means for controlling a vehicle.