JPH05272629A - Shift controller for automatic transmission - Google Patents

Abstract

PURPOSE:To reduce a speed change shock by controlling, at the time of speed change to a low-speed side, the operating moment of a speed change mechanism in accordance with a vehicle speed signal and a throttle opening, and making the rotation speed of an output shaft of an automatic transmission approximate to the revolution speed of an engine at the time when the speed change is completed. CONSTITUTION:When, in an automatic transmission of forward 3 speed stage, and backward 1 speed stage, change in speed from 3rd speed stage to a 2nd speed stage for example is determined in accordance with a vehicle speed signal from a vehicle speed sensor 12 and a throttle opening signal from a throttle sensor 13, a speed change instruction to shift solenoids A, B is issued whereupon the speed is first changed to 1st speed stage. Then, comparison is made between a set value of 1st speed retention time period and an actual retention time period by use of a vehicle speed signal from the vehicle speed sensor 12 and a throttle opening signal from the throttle sensor 13. If the actual retention time period already reaches the set value, a speed chance instruction signal is generated to the shift solenoid B whereupon change to the 2nd speed stage is completed. During 1st speed retention time period as well, the vehicle speed signal and the throttle opening signal retention are always monitored whereby an adequate 1st speed time period is ensured in case the throttle opening is varied too.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is mainly applied to vehicles, machine tools,
It can be applied to shift control devices for automatic transmissions such as construction machinery.

[0002]

2. Description of the Related Art Conventionally, a shift control device for an automatic transmission equipped with a shift mechanism used in a vehicle or the like has a shift switch when sudden acceleration (kick down) is performed by a driver's depression of an accelerator pedal. Based on the shift switch signal from the vehicle, the vehicle speed signal from the vehicle speed sensor, or the throttle opening signal from the throttle sensor, the control circuit transmits a gear shift instruction signal to the speed change mechanism. Here, the speed change mechanism of the automatic transmission is usually formed by a plurality of clutches and brakes configured by a multi-plate clutch,
At the time of gear shifting, the gear stage is determined by the combination of engagement and release of the clutch and brake. In an actual gear shift operation, in order to avoid a gear shift shock due to a shift in the timing of engagement and disengagement of the clutch and brake, for example, 3
At the time of shifting from the third speed to the second speed, the third speed is once shifted to the first speed, the first speed is held for a predetermined time to synchronize the operation of the clutch and the brake, and then the second speed is changed again. ..

However, in the above-mentioned prior art, for example, when shifting from the 3rd speed to the 2nd speed, the predetermined time to be held in the 1st speed is determined only by the vehicle speed. If higher than the number of revolutions, 2
At the same time when the shift to the high speed was completed, the engine brake was applied, and the driver might feel a shock to the vehicle.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shift control device for an automatic transmission which causes less shift shock when shifting to a low speed side.

[0005]

In order to solve the above problems, according to the present invention, a shift control device for an automatic transmission having a shift mechanism detects a shift switch for detecting a shift position position and a vehicle speed. A vehicle speed sensor, a throttle sensor that detects the throttle opening of the engine,
The vehicle speed sensor is provided with a control circuit that transmits a shift instruction signal based on a shift switch signal from the shift switch, a vehicle speed signal from the vehicle speed sensor, or a throttle opening signal from the throttle sensor, and the vehicle speed sensor when shifting to a low speed side. The shift control device for an automatic transmission is characterized in that the operation timing of the shift mechanism is controlled by a vehicle speed signal from the vehicle and a throttle opening signal from a throttle sensor.

[0006]

The operation timing of the speed change mechanism is controlled by the vehicle speed signal from the vehicle speed sensor and the throttle opening signal from the throttle sensor when shifting to the low speed side.
When the shift is completed, the rotation speed of the output shaft of the automatic transmission can be brought close to the engine rotation speed, and the shift shock can be reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of an automatic transmission of third forward speed and first reverse speed to which the present invention is applied, and FIG. 3 is a system diagram thereof. Power from an engine (not shown) is transmitted to the drive plate 1, transmitted to the input shaft 3 via the torque converter 2, and input to the transmission mechanism 4. The speed change mechanism 4 includes a C1 clutch 5, a C2 clutch 6, a B1 brake 7, a B2 brake 8, and a one-way clutch 9. Here, for example, when the shift position is in the third speed, as shown in Table 1, the C1 clutch 5 and the C2
The clutch 6 operates together and is in the engaged state, and the power transmitted to the input shaft 3 is the C1 clutch 5 and C1.
It is transmitted to the output shaft 10 via the two-clutch 6 and is transmitted to the wheels of the vehicle via a differential device (not shown).

Table 1

[0009]

[Table 1]

Here, when a rapid acceleration (kick down) is performed by the driver depressing the accelerator pedal, the shift switch signal from the shift switch 14 shown in FIG.
Vehicle speed signal from vehicle speed sensor 12, throttle sensor 13
Based on the throttle opening signal from, the CPU 15, which is a control circuit, sends a shift instruction signal to the shift solenoid A16 and the shift solenoid B17, and the shift operation is performed.

As shown in Table 1, when the gear is in the third speed, as described above, the C1 clutch 5 and the C2 clutch 6 are used.
Both are in the engaged state, while the C1 clutch 5 and the B1 brake 7 are both in the engaged state when in the 2nd speed, the C2 clutch is in the engaged state when shifting from the 3rd speed to the 2nd speed. In order to avoid a timing difference between the release of C6 and the engagement of the B1 brake 7, the C2 clutch 6 is once released to
The speed is changed to a high speed and is maintained for a predetermined time. Here, the CPU 1
Reference numeral 5 determines, based on the vehicle speed signal from the vehicle speed sensor 12 and the throttle opening signal from the throttle sensor 13, the time period in which the gear stage is held at the first speed as described above. In practice, the retention time is determined by the map shown in FIG. After the end of the holding time, the shift solenoid B is activated by the operation instruction signal sent from the CPU 15.
17 operates to engage the B1 brake 7 to complete the shift to the 2nd speed. As described above, since the holding time for the first speed is set by the vehicle speed signal from the vehicle speed sensor and the throttle opening signal from the throttle sensor, the holding time is set only by the vehicle speed signal. Compared with the case, the speed of the output shaft of the automatic transmission can be brought closer to the engine speed when the shift to the second speed is completed,
Shift shock can be reduced.

FIG. 4 is an example of a flow chart of the control program of the present invention. When it is determined in 18 that the gear position is to be changed from the third speed to the second speed on the basis of the vehicle speed signal from the vehicle speed sensor 12 or the throttle opening signal from the throttle sensor 13, the shift solenoid A16 is determined at 19 , And a shift instruction signal to the shift solenoid B17 is transmitted, and the gear is first shifted to the first speed. After that, at 21, the set value of the 1st speed holding time determined based on the vehicle speed signal from the vehicle speed sensor 12 and the throttle opening signal from the throttle sensor 13 is compared with the actual holding time, and the actual holding time is compared. If the holding time of has reached the set value, the shift command signal is transmitted to the shift solenoid B17 at 22 and the shift to the second speed is completed. Here, since the vehicle speed signal and the throttle opening signal are constantly monitored in 20 of the flowchart even during the holding time at the 1st speed, even if the throttle opening changes during that time, the appropriate 1st speed holding time is maintained. Can be secured.

In the above embodiment, the case where the present invention is applied to the automatic transmission of the third forward speed and the first reverse speed is shown, but the present invention is not limited to this. For example, the automatic transmission of the fourth forward speed. There is no problem even if applied to.

[0014]

According to the present invention, when shifting to the low speed side,
Since the operation timing of the transmission mechanism is controlled by the vehicle speed signal from the vehicle speed sensor and the throttle opening signal from the throttle sensor, the rotation speed of the output shaft of the automatic transmission can be brought close to the engine rotation speed when the shift is completed. The shift shock can be reduced.

Further, since the vehicle speed signal and the throttle opening signal are constantly monitored during the holding time at the low speed stage, an appropriate low speed stage holding time can be secured even if the throttle opening changes during that time. ..

[Brief description of drawings]

FIG. 1 is a sectional view of an automatic transmission to which the present invention is applied.

FIG. 2 is a map of 1st speed holding time of the present invention.

FIG. 3 is a system diagram of a shift control device for an automatic transmission according to the present invention.

FIG. 4 is a flowchart of a control program of a shift control device for an automatic transmission according to the present invention.

[Explanation of reference numerals] 4 speed change mechanism 12 vehicle speed sensor 13 throttle sensor 14 shift switch 15 CPU

Claims (1)

[Claims] 1. A shift control device for an automatic transmission having a shift mechanism, comprising a shift switch for detecting a shift position position, a vehicle speed sensor for detecting a vehicle speed, and a throttle sensor for detecting a throttle opening of an engine. A shift circuit signal from the shift switch, a vehicle speed signal from the vehicle speed sensor, or a throttle opening signal from the throttle sensor, and a control circuit for transmitting a shift instruction signal based on the throttle opening signal. A shift control device for an automatic transmission, wherein an operation timing of the shift mechanism is controlled by a vehicle speed signal from a sensor and a throttle opening signal from a throttle sensor.