JPH0361757A - Shift shock reducing device for automatic transmission - Google Patents

Abstract

PURPOSE:To secure good shift feeling by providing a shift shock judging means, a shift time judging means, and an accumulator pressure correction quantity learning means correcting an accumulator based on the length of the shift time when a shift shock occurs. CONSTITUTION:For shift control, a vehicle speed V is D/A-converted, acceleration alpha is calculated by differentiating the vehicle speed V, the peak value alphap of acceleration and target acceleration alphad are compared, and it is judged that a shift shock occurs if alphap>alphad. The shift time is judged by comparing the shift time Ts until the shift shock occurs after the shift start and the target shift time Td. If Ts<Td at a quick shift, the accumulator pressure is decreased by the correction quantity - P, the engagement of a shift clutch 1 is delayed, and the shift shock is corrected to a low shift shock. If Ts<=Td at a slow shift, the pressure of an accumulator 10 is increased by the correction quantity P, the coupling of the clutch 1 is accelerated, and the shock is reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a shift shock reducing device that reduces the shock that occurs when shifting in a vehicle automatic transmission. Concerning learning and controlling.

[Conventional technology]

Generally, in automatic transmissions, multiple clutches or brakes attached to fixed elements of planetary gears are selectively engaged using hydraulic pressure to automatically control gear changes, so the engaged state of these clutches directly affects the gear shift shock. affect.

Therefore, as a measure to reduce the shock, it is effective to suppress the rise in the hydraulic pressure of the clutch, but this causes a delay in gear shifting.

Therefore, it is desirable to speed up the shift while suppressing shock. As a countermeasure to this, a pressure adjustment means such as an accumulator is provided in the hydraulic pressure circuit for each clutch, and the rise of the hydraulic pressure is changed in stages. It has also been proposed to variably control the stiffness in the middle of this hydraulic characteristic depending on the operating conditions, emphasizing shock reduction under low loads and speeding up gear changes under high loads.

Although a good shift feeling can be obtained by controlling the working oil pressure using the accumulator, this may deteriorate due to variations in the working oil pressure, clutch friction coefficient μ, engine torque, etc., and changes over time. For this reason, it is particularly desirable to learn the actual state of shift shock and always optimally correct the stiffness caused by the accumulator, thereby maintaining a state in which shift shock is reduced.

Conventionally, regarding this type of shift shock mitigation measures, there is a prior art, for example, disclosed in Japanese Patent Application Laid-Open No. 62-56656. Here, it is shown that a torque sensor is used to detect changes in the output shaft torque, and the quality of the gear shifting operation is evaluated based on the torque fluctuation width to adjust the fluid pressure.

[Problem to be solved by the invention]

By the way, in the prior art described above, separate torque sensors are required for each, and changes in torque must be detected accurately. Furthermore, since the judgment is made only based on the variation range of the output shaft torque, the variation range is always uniformly controlled, and it is difficult to apply this method to devices that speed up gear changes depending on the load or the like. Furthermore, although the magnitude of the shift shock can be determined, the timing of the shock occurrence is not detected, so there is a risk of erroneous determination due to torque fluctuations other than shift changes.

The present invention has been made in view of the above points, and its purpose is to accurately detect the actual shift shock condition from the time of occurrence of the shift shock magnitude 1 without using a special sensor, An object of the present invention is to provide a shift shock reducing device for an automatic transmission capable of performing learning control so as to ensure a comfortable shift feeling.

[Means to solve the problem]

In order to achieve the above object, the shift shock reducing device for an automatic transmission according to the present invention includes an accumulator connected to a hydraulic oil path for the hydraulic pressure to the transmission clutch, and at least a control unit connected to the accumulator pressure oil path on the back pressure side of the accumulator. In a hydraulic shift control system having a duty solenoid that variably controls the accumulator pressure using an electric signal from the vehicle, there is provided a shift shock determination means for determining the magnitude of the actual shift shock based on the acceleration of the vehicle body, and a shift shock determination means that determines the magnitude of the actual shift shock from the start of the shift until the shift shock occurs. The present invention includes a shift time determining means for determining the length of the shift time, and an accumulator pressure correction amount learning means for correcting the accumulator based on the length of the shift time in a state where a shift shock occurs.

[For production]

Based on the above configuration, the rise of the working oil pressure introduced into the speed change clutch of the automatic transmission is smoothed by the accumulator pressure of the accumulator, and the clutch is quickly engaged and speed is changed with little speed change shock. Then, the accumulator pressure is corrected by the accumulator pressure correction amount learning means based on the actual speed change and shift time during the speed change.
Individual difference.

This has been corrected so that a low shift shock occurs at an appropriate shift time due to changes over time. In this way, a good shift feeling can always be obtained, and shift shock can be effectively reduced.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, the power train of the automatic transmission is omitted, and the hydraulic speed change control system will be described. Reference numeral 1 indicates a speed change clutch, and the line pressure from the pressure regulating valve 3 that regulates the discharge pressure from the oil pump 2 is Uraji 4 is manual valve 5. It communicates with the speed change clutch l via the shift valve 6. A pilot pressure oil passage 9 having a shift solenoid 8 communicates with the shift valve 6, and at a predetermined gear stage, the shift solenoid 8 applies pilot pressure to the shift valve 6 and operates the shift valve 6, thereby transmitting line pressure to the shift clutch I. It is designed to guide and engage.

Further, as a measure to reduce shift shock, an accumulator I0 is connected to the line pressure path 4 immediately before the shift clutch 1.

In the accumulator 10, a spring tab is applied to one side of the piston 10a, and a back pressure chamber toe communicates with an accumulator control valve 12 via an accumulator pressure oil passage 11. A pilot pressure passage 9 having a duty solenoid 13 is connected to the control side of the accumulator control valve 12, and the pilot pressure from the duty solenoid 13 controls the accumulator pressure of the accumulator control valve 12, and the back pressure of the accumulator 10, i.e. Adjust the hydraulic pressure level of the speed change clutch l.

Regarding the electronic control system, it has a vehicle speed sensor 16 and a throttle opening sensor 17. Vehicle speed V of vehicle speed sensor 16 and throttle opening θ of throttle opening sensor 17
is input to the shift control means 21 of the control unit 20, and outputs a shift signal to the shift solenoid 8 based on a shift pattern based on the vehicle speed V and the throttle opening θ. In addition, the throttle opening θ is manually input to the accumulator pressure setting means 22, and the clutch pressure Pc is
The accumulator pressure (shelf floor) Pa provided in the front stage of
It is determined (for example, proportionally) according to the throttle opening degree θ.

Next, as a learning control system for reducing shift shock, the vehicle speed V of the vehicle speed sensor 16 is converted into an analog value by the D/A converter 18 and manually inputted to the acceleration calculation means 23, and the vehicle speed V is differentiated to calculate the acceleration α, α Calculated by -dv/dt. This acceleration α is manually input to the shift shock determining means 24, but the target acceleration α6 is set in advance by the target acceleration setting means 25 based on the vehicle speed V at the time of shifting, the throttle opening θ, etc., and this target acceleration α is also input to the shift shock The determination means 24 is manually operated. Here, since the peak value αP of the acceleration α matches the magnitude of the shift shock, the peak value α and the target acceleration α6 are compared as shown in FIG. Determine gear shift shock.

The shift shock signal and the shift start signal of the shift control means 21 are input manually to the shift time calculation means 26, and as shown in FIG. 3, the shift time T until the acceleration peak value αP is generated after the shift command is calculated. measure.

In addition, the type of shift (1-2,
2-3), the target shift time T4 is set in advance based on the vehicle speed V and the throttle opening θ, and this target shift time T4
6 and the shift time Ts to determine whether the shift time is long or short. These shift shock and shift time determination signals are manually input to the accumulator pressure correction amount learning means 2B to set the correction amount ±ΔP.

Here, when a shift shock occurs with αP>α6, Ts
In the case of Td, it can be determined that the accumulator pressure Pa is too large and the gear shift is rapid, causing a shift shock, and therefore the correction amount -ΔP is set. On the other hand, T
If 5≧T6, it can be determined that the accumulator pressure Pa is too small and the shift is slow, and therefore the correction amount ΔP is set.

This correction amount ΔP is determined by the accumulator pressure setting means 22.
Accumulator pressure P stored in RAM
The value of a is corrected by ±ΔP.

In order to prevent erroneous determination due to fluctuations in the acceleration α on rough roads, a rough road driving determining means 29 is provided to which the acceleration α and the shift signal are input. If the amplitude of the peak value α is greater than the set value after a predetermined time has elapsed after the start of gear shifting,
It is determined that the road is rough and learning by the accumulator pressure correction amount learning means 28 is interrupted.

Next, the operation of the shift shock reducing device for an automatic transmission having such a configuration will be described.

First, the accumulator pressure Pa is set according to the throttle opening θ in the engine operating state, and the duty solenoid 1
3, and this duty pressure acts on the accumulator control valve 12 to reduce the back pressure chamber 10c of the accumulator 10.
is controlled so that it becomes accumulator pressure Pa. Therefore, during gear shifting, when a shift signal is input to the shift solenoid 8 and the shift valve 6 is operated to communicate, the line pressure in the line pressure oil passage 4 is introduced to the gear change clutch t, but at this time, the line pressure is also introduced to the accumulator IO. to operate the piston loa. Due to this change in the volume of the accumulator IO, the rise of the clutch operating oil pressure becomes smooth as shown in Fig. 2, reducing the shift shock, and after reaching a balance with the accumulator pressure Pa, the clutch operating oil pressure rises again, and the shifting clutch l is engaged to complete the gear shift.

Here, when the load is low, the tank pressure of the clutch operating oil pressure is set low together with the accumulator pressure Pa, so that the gears are shifted smoothly. On the other hand, when the load is high, the accumulator pressure Pa becomes high and the gears are changed quickly.

By the way, during such shift control, the flowchart shown in FIG. 4 is executed, and the accumulator pressure Pa is controlled to learn based on the actual state of shift shock. That is, step 5
At step 100, the vehicle speed V is read, at step 5tot, the vehicle speed V is D/A converted, at step 5102, the acceleration α is calculated by differentiating the vehicle speed V, and at step 5103, the peak acceleration value αP and the target acceleration α are calculated. be compared.

If α, >α6, it is determined that a shift shock has occurred, and the process proceeds to step 5t04, where the shift time is determined by comparing the shift time T from the start of the shift until the shift shock occurs with the target shift time T4. Ru. In this way, the magnitude and occurrence state of the actual shift shock are detected, and if the shift is fast (Ts<Td), the process proceeds to step 8105, where the accumulator pressure Pa is corrected to decrease by the correction amount -ΔP. Therefore, as shown in Fig. 2, the tank pressure of the clutch operating oil pressure Pc is
It becomes slightly lower in accordance with the correction amount -ΔP, and accordingly, the engagement of the shift clutch l becomes slower, and as shown by the broken line in FIG. 5(a), the target acceleration αd is also reached at approximately the target shift time T4
It has been corrected to cause the following low gear shift shock.

On the other hand, if the shift is slow with Ts≧Td, step 5I0B
Then, the accumulator pressure Pa is increased by the correction amount ΔP. For this reason, as shown in Fig. 2, the tank pressure becomes slightly higher and the engagement of the transmission clutch l becomes faster, as shown in Fig. 5(b).
As shown by the broken line, in this case as well, the adjustment is made so that a shock as low as the target acceleration α or less occurs at approximately the target shift time T.

In this way, the smooth latch engagement state due to the accumulator pressure Pa is optimized, reducing shift shock and always providing a good shift feeling.

Note that if the variation in acceleration α is large due to a reason other than gear shifting, it is determined that the vehicle is traveling on a rough road and the above-mentioned learning control is interrupted, thereby preventing the accumulator pressure Pa from being erroneously corrected.

Although the embodiments of the present invention have been described above, an acceleration sensor may be attached to directly detect acceleration.

〔Effect of the invention〕

As described above, according to the present invention, in an automatic transmission, in an extraction pressure shift control system that smoothly controls the rise of the clutch operating oil pressure using an accumulator, the reservoir pressure of the clutch operating oil pressure is corrected and controlled together with the accumulator pressure. Therefore, the shift feeling can be favorably corrected for individual differences, changes over time, etc., and shift shock can be effectively reduced.

Furthermore, since the accumulator pressure is corrected by learning the magnitude and occurrence state of the actual shift shock, it can be applied even when the accumulator pressure is controlled by other factors, and the shift shock can be accurately determined to improve the shift feeling. can be optimized.

Furthermore, since the accumulator pressure is corrected by learning the magnitude and occurrence state of the actual shift shock, it can be applied even when the accumulator pressure is controlled by other elements, and the shift shock can be accurately cut off to improve the feeling. can be optimized.

Further, shift shock can be determined with high accuracy based on vehicle body acceleration and shift time, and accumulator pressure compensation IE can be appropriately performed in relation to shift time.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of the shift shock reduction device for an automatic transmission of the present invention, Fig. 2 is a hydraulic pressure characteristic diagram of a shift clutch, and Fig. 3 is a characteristic of vehicle speed and acceleration showing a shift shock state. 4 is a flowchart of the action of reducing shift shock, and FIG. 5 is a diagram showing a state of reducing shift shock by hydraulic pressure correction. . l...speed change clutch, IO...accumulator, 1
DESCRIPTION OF SYMBOLS 1...Accumulator pressure oil path, 12...Accumulator control valve, 18...Duty solenoid, 2
0: Control unit, 24: Shift shock determination means, 26: Shift time calculation means, 28: Accumulator pressure correction amount learning means

Claims (2)

[Claims] (1) Hydraulic pressure having an accumulator connected to the oil passage for hydraulic pressure to the transmission clutch, and a duty solenoid in the accumulator pressure oil passage on the back pressure side of the accumulator for variably controlling the accumulator pressure using at least an electric signal from a control unit. In the shift control system, the shift shock determining means determines the magnitude of the actual shift shock based on the vehicle body acceleration, the shift time determining means determines the length of the shift time from when the shift starts until the shift shock occurs, and the shift shock occurrence state. 1. A shift shock reduction device for an automatic transmission, comprising: an accumulator pressure correction amount learning means for correcting an accumulator depending on the length of shift time. (2) The automatic accumulator pressure correction amount learning means according to claim (1), wherein the accumulator pressure correction amount learning means corrects to decrease the accumulator pressure when the shift time is short in a state where a shift shock occurs, and compensates to increase the accumulator pressure when the shift time is long. Gear shift shock reduction device for transmission.