JPH066815U - Automatic transmission - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an automatic transmission that can automatically shift down depending on vehicle speed and deceleration. The automatic transmission according to the present invention is provided with a map in which a control device stores a set-down vehicle speed and a set deceleration for each gear, and a current gear when the accelerator switch is off. When the vehicle speed is lower than the set vehicle speed for shift down and lower than the set deceleration, it is possible to shift down to the gear specified by the map, so that it is possible to effectively exert the engine brake and increase the speed. The acceleration of time is improved, and meaningless auto downshift can be avoided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an automatic transmission, and more particularly, to an automatic transmission that can automatically shift down according to vehicle speed and deceleration.

[0002]

[Prior art]

 Many attempts have been made to improve engine braking performance of automatic transmissions and automatically shift down. For example, the automatic transmission disclosed in Japanese Unexamined Patent Publication No. Sho 63-209051 responds to the engine braking force and the allowable rotational speed of the engine for each gear stage corresponding to the vehicle speed and the braking force, in response to the current gear stage. The engine braking performance is improved by automatically shifting to the lower gear. The automatic transmission disclosed in Japanese Utility Model Laid-Open No. 63-18336 operates the exhaust brake in response to the rate of change in engine speed, synchro speed, and vehicle speed to control the transmission shift set. It improves the operating performance of. In addition, Japanese Utility Model Laid-Open No. 61-108560 discloses an automatic transmission capable of shifting the downshift map to the low speed side based on the vehicle speed and accelerator opening. No. 44054 discloses an automatic transmission capable of canceling the shift down on the basis of the vehicle speed and the accelerator opening. Japanese Utility Model Laid-Open No. 60-154650 discloses an automatic transmission. However, an automatic transmission provided with an instruction switch for holding downshift is disclosed. Further, Japanese Utility Model Laid-Open No. 61-79050 discloses downshifting at a lower speed side than usual and shifting up at a higher speed side. An automatic transmission that has a map and can perform shift switching according to the map is disclosed.

However, in a conventional shift control technique for an automatic transmission as disclosed in Japanese Patent Laid-Open No. 63-64830, an automatic downshift function is required when the accelerator is off or the brake is on. , The engine brake was not effective because it did not downshift to the lower gear. In addition, it is possible to shift down to a lower speed, but in this case, since it is a function to shift down when the vehicle speed decreases to the set vehicle speed, during strong braking, meaningless shift just before stopping I tended to go down.

[0004]

[Problems to be solved by the device]

 Therefore, an object of the present invention is to improve the performance of an engine brake by automatically downshifting depending on the vehicle speed and deceleration in view of the above-mentioned problems of the conventional automatic transmission transmission control technology. At the same time, it is an object of the present invention to provide an improved shift control technique for an automatic transmission, which prohibits meaningless downshifting and further improves re-acceleration by setting a gear up to a low speed stage.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the engine includes a rotation sensor for an engine, a stroke sensor for a clutch actuator, a vehicle speed sensor, a shift and select position sensor, and an accelerator sensor configured according to the present invention. In an automatic transmission having a control device that operates a clutch and a transmission actuator according to signals from the respective sensors, the control device stores a downshift set vehicle speed and a set deceleration for each gear position. When the accelerator switch is off, it has a function to shift down to the gear position specified in the map when the vehicle speed is less than the set vehicle speed of the shift down for the current gear position and less than the set deceleration speed. ing.

[0006]

[Action]

 Since the automatic transmission according to the present invention is configured as described above, when the accelerator is off or the brake is on, when the vehicle speed decreases to a set vehicle speed at which engine braking is ineffective, the automatic transmission is sequentially shifted to a lower speed stage. It is possible to perform down and effectively operate the engine brake. Also, in the case of sudden braking, the vehicle speed will drop significantly during downshifting, and the effect of engine braking cannot be expected. Therefore, downshifting is prohibited when the deceleration exceeds the set deceleration. This allows engine braking to be activated only when necessary.

[0007]

【Example】

 A preferred embodiment of an automatic transmission according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram of a vehicle drive transmission system incorporating an automatic transmission according to the present invention. As shown in FIG. 1, an automatic transmission 14 of the present application includes an engine rotation speed sensor 18 for monitoring the rotation speed of an engine 10 and a stroke sensor for monitoring a stroke of a clutch actuator 12 that operates a clutch 11. 13, a vehicle speed sensor 16 for monitoring the vehicle speed, a shift and select position sensor 17 for monitoring the shift and select positions of the transmission actuator 15, and an on / off state of the accelerator. The accelerator sensor 29 is included. The CPU 19 receives a signal from each sensor and a signal from the brake switch 21 and operates the actuators 12 and 15 of the clutch 11 and the automatic transmission 14 to control the shift change.

The operation of the automatic transmission according to the present invention can be easily understood with reference to the shift-down conceptual diagram shown in FIG. 2 and the flow chart shown in FIG.

First, when the shift control flow of the automatic transmission according to the present invention is entered at 30, it is determined at 31 or 32 whether the accelerator is off or the brake is on, respectively, and the vehicle is invented according to the present invention. It is determined whether the engine braking control based on the above is required. If it is determined at 31 or 32 that the accelerator is off or the brake is on, then at 33, it is determined whether the vehicle speed is equal to or higher than the set vehicle speed for clutch disengagement. If the vehicle speed is less than the set vehicle speed with the clutch disengaged, it is not necessary to shift down according to the present invention, so the routine proceeds to 38 and the control flow is stopped.

However, when the vehicle speed is equal to or higher than the set vehicle speed with the clutch disengaged, it is determined whether the vehicle speed is equal to or lower than the set vehicle speed corresponding to the current gear position (see FIG. 2 for the third gear position. The down set vehicle speed is V1 and the shift down set vehicle speed is V2 for the second gear.) Is determined at 34. When the vehicle speed is equal to or higher than the set vehicle speed, the control based on the present application is unnecessary, and the control flow is returned to the original. Furthermore, whether or not it is less than or equal to the set deceleration corresponding to the current gear stage (also refer to FIG. 2, for the 3rd gear, the downshift set deceleration is G1 and The shift-down set vehicle speed is G2 for the gear position), and it is determined at 35. Similarly, when the deceleration is equal to or higher than the set deceleration, the control based on the present application is unnecessary, and the control flow is returned to the original state.

Next, at 34 and 35, if it is determined that the vehicle speed is not more than the set down speed (V1, V2) for the current gear and the set deceleration (G1, G2) or less, at 36. If the gear of the transmission is set to the optimum gear according to the vehicle speed and the gear of the transmission is the low gear, shift down to the gear specified in the map based on the present invention at 37. The control flow according to the present invention then ends at 38, otherwise the control flow is reverted.

[0013]

[Effect of device]

 As described above, the automatic transmission according to the present invention automatically downshifts when the vehicle speed is equal to or higher than the set vehicle speed and is equal to or lower than the set deceleration rate, so that the effect of engine braking can be appropriately exerted. In addition, since meaningless auto downshift is avoided, operability is improved and the service life of the automatic transmission can be extended. Also, since the gear is set up to the low speed stage, it is possible to improve the re-acceleration property when increasing the speed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a vehicle drive system incorporating an automatic transmission according to the present invention.

FIG. 2 is a conceptual diagram of downshifting of an automatic transmission according to the present invention.

FIG. 3 is a flowchart showing a shift control method for an automatic transmission according to the present invention.

[Explanation of symbols]

 10 ... Engine 11 ... Clutch 12 ... Clutch Actuator 13 ... Stroke Sensor 14 ... Automatic Transmission 15 ... Transmission Actuator 16 ... Vehicle Speed Sensor 17 ... Shift and Select Position sensor 18 ... Engine speed sensor 19 ... CPU 20 ... Accelerator sensor 21 ... Brake switch

Claims (1)

[Scope of utility model registration request] 1. A rotation speed sensor for an engine, a stroke sensor for a clutch actuator, a vehicle speed sensor, a shift and select position sensor, and an accelerator sensor, and actuators for the clutch and the transmission according to signals from the sensors. In the automatic transmission having a control device for operating the control device, the control device has a map in which set vehicle speeds and set decelerations for downshift are stored for respective gears, and when the accelerator switch is off, a current map is stored. An automatic transmission having a function of downshifting to a gear designated by the map when the vehicle speed is equal to or lower than a set vehicle speed for the downshift and is equal to or lower than a deceleration set for the gear.