JPH056065B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for an automatic transmission that ensures reliable shifting during gear changes.

(Prior Art) In automatic transmissions for vehicles, since shifts are not performed manually, the completion of a shift cannot be detected by a tactile response. Therefore, it is necessary to detect the completion of the shift using a position sensor such as a switch, and take measures based on this to prevent shift abnormalities such as poor shifting or excessive shifting.

(Problem to be Solved by the Invention) However, the switch serving as the position sensor needs to be set at a position where it turns on and off while the gears of the transmission are actually engaged.
In addition to complicating the selection and installation of the setting position, there was also the drawback that the shift position could not be determined due to chattering, a problem peculiar to switches. As a result, problems such as poor shifting and gear noise have arisen.

The present invention solves such conventional problems, and aims to prevent undershifting and overshifting by always setting the shift position on the shift side of the detent depression position.

(Means for Solving the Problems) The present invention provides a shift actuator that is controlled by a stroke sensor that detects the position of the shift actuator so that its position becomes a target value during gear shifting; In a vehicle automatic transmission that is mechanically connected and equipped with a detent mechanism for gear detent, a means is provided for reading a value of a stroke sensor in a detent depression state after hydraulic pressure for driving a shift actuator is released, and If the value of the stroke sensor is closer to the shift than the target value, set the target value for the next shift to the value of the stroke sensor, or the intermediate value between the stroke sensor value and the target value. The feature is that it is updated so that the value becomes . By repeatedly performing such control while the vehicle is running, the target value for the next shift will be selected as the value that is closest to the shift among the previous target values of the stroke sensor.

(Function) After the shift actuator completes the shift operation, the valve operation is released, and at this time, the hydraulic pressure of the shift actuator becomes free, allowing the detent mechanism to move freely due to the vibration of the gear. In this state, the detent mechanism stabilizes the position of the shift actuator at a position where the gears are engaged normally. The shift stroke at this time is read, and if it is closer to the shift than the previous target value, the target value is updated. That is, the shift stroke position closest to the shift so far is determined as the target shift stroke position for the current gear, and the shift actuator is controlled so that the gears are engaged at this target shift stroke position. This prevents gear slippage due to insufficient shifting and damage to the dog teeth due to excessive shifting.

(Example) FIG. 1 shows a shift actuator 1 used in the present invention, which is configured to be able to stop at three positions. This consists of a stepped cylinder 1a, a first piston 1b, and a cylindrical second piston 1c that fits into the first piston 1b. A shift lever 1e is attached. The piston rod 1d is connected to both oil chambers 1f, 1 of the stepped cylinder 1a.
g is in a neutral state, and when the oil pressure acts on the oil chamber 1g, the first piston 1b moves to the left together with the second piston 1c, and when the oil pressure acts on the oil chamber 1f, the first piston 1b moves to the left. Only the piston 1b moves to the right. 2 and 3 are pressure supply valves, and hydraulic pressure source 4
and the oil chambers 1f and 1g. 5,
Reference numeral 6 denotes a discharge pressure valve, which is connected between the tank 7 and the oil chambers 1f and 1g.

8 is an engagement recess 8 that engages the end of the shift lever 1e.
This shift fork shaft 8 has a shift lock 8b with a
A shift fork 9 is attached to the. 1
0 is a sleeve that engages with the end of the shift fork 9, 1
1 is an insert, 12 is a synchronizing blocking ring that is laterally moved by the insert 11, and 13 is a gear.

The shift fork shaft 8 is provided with three detent grooves 14 corresponding to, for example, second stage, neutral, and first stage shift positions. The ball 16 is pressed against the ball 16 to maintain the shift stroke position of the shift fork shaft 8 with a constant pressure. In addition, these day tent grooves 1
4, a spring 15, and a steel ball 16 constitute a detent mechanism 19. Further, 17 is a stroke sensor that detects the stroke position of the piston rod 1d, that is, the current shift stroke of the shift actuator 1, and 18 is an electronic control device, which controls the output of the stroke sensor 17, the rotational speed of the engine, Based on various signals such as vehicle speed and select lever position, the pressure supply valves 2 and 3 and the exhaust pressure valves 5 and 6 are selectively operated to shift the shift actuator to one of the three positions. .

Next, the operation of the automatic transmission for a vehicle is controlled by a second
This will be explained according to the flowchart shown in the figure.

For example, when shifting from the neutral position to the first gear, a shift signal based on a predetermined select lever operation is input to the electronic control unit 18 (step a). Therefore, while the supply pressure valve 2 is open, the supply pressure valve 3 is closed, and the exhaust pressure valve 5 is closed, the exhaust pressure valve 6 is opened, and the oil chamber 1f of the shift actuator 1 is communicated with the hydraulic pressure source 4. , the piston rod 1d moves to the right in the figure.

On the other hand, the electronic control device 18
7 detects the shift amount, and at the predetermined shift stroke position where the gears are thought to be engaged,
The exhaust pressure valve 6 is closed and the shift actuator 1 is stopped. At this time, due to the rightward movement of the shift fork shaft 8, the neutral daytent groove 14 of the daytent mechanism 19 climbs over the steel ball 16 and passes through the adjacent first stage daytent groove 14.
engages the steel ball 16. In this way, the shift actuator 1 shifts the gear to the target shift stroke position S (step b).

After that, the electronic control device 18 controls the pressure supply valve 2,
3. Release the control of the exhaust pressure valves 5 and 6 to make them free (step c). For this reason, oil chambers 1f, 1
g will both be in communication with the tank 7, and the shift actuator 1 will also be in a free state. In addition,
At this time, the sleeve 10 of the transmission is engaged with the gear 13, and while the vehicle is running in that gear, vibrations of the gear 13 are transmitted through the sleeve 10 and the shift fork 9 to the daytent mechanism 19 and the shift actuator 1. The detent mechanism receives the vibration and can move freely as shown in FIG.

Therefore, when shifting to that gear, initially it is carried out according to a fixed control map, but once the vehicle is driven in that gear, the shift position of that gear is determined by the day tent mechanism 19. ,
The upper and lower limits are limited, and a stable gear engagement position is determined.

Therefore, when the learning timing has arrived, that is, when it is determined that the reading timing has arrived by the stroke sensor 17 (step d),
The shift stroke at that gear is read from the stroke sensor 17 (step e), and the current shift stroke position P1 thus read is determined as the previous target shift stroke position g, as shown in FIG.
1. It is determined whether or not it is on the shift side rather than g2 (step f), and if it is determined that it is on the shift side, only if the shift to that shift side is not abnormal (step g). The position of the shaft stroke, that is, the shift stroke position when the shift stroke is the closest to the shift up to now, is set as the target shift stroke position for shifting that gear (step h). Next, it is determined whether the shift position is maintained as it is (step i), and if the shift position is maintained, the control from step d to step h is repeated, and if the shift position is not maintained, the control is shifted to neutral. (step j).

In this manner, by repeating the setting of the target shift stroke position in step h, it is possible to prevent gear slippage due to insufficient shift amount and damage to dog teeth due to excessive shift.

Furthermore, according to the above shift method, the transmission itself,
The above-mentioned shift can be performed reliably and without being affected by variations in dimensions of the linkage mechanism of the shift actuator 1, play, variations in the characteristics of the stroke sensor 17, and wear of the engagement recess 8a of the shift lever 1e and shift fork shaft 8. Can be done safely.

Note that the new target shift stroke position set in step h can be less affected by reading of abnormal data by performing a certain weighted average according to the following equation.

S=[(S×K)+S']/K+1 where S on the left side is the target shift stroke position, S on the right side is the previous target value, S' is the current shift stroke position, and K is the weighting coefficient.

When the target stroke position is determined by this formula, the new target value is set to a value intermediate between the read current stroke position and the previous target value.

(Effects of the Invention) According to the present invention, the shift actuator is able to move freely in the detent depressed state when the hydraulic pressure to the shift actuator is released after the end of the shift. If the shift stroke in the current state is read from the stroke sensor, and if the stroke sensor value is closer to the shift than the previous target value, the target value for the next shift will be set to the value of the stroke sensor (that is, the current value). The shift control is executed by updating the stroke sensor to a value that is the closest to the shift position among the learned values up to that point, or to a value that is intermediate between the value of the stroke sensor and the target value. Thereby, when changing gears, it is possible to effectively prevent gear slippage due to insufficient shifting, damage to dog teeth due to excessive shifting, etc.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a shift mechanism for explaining the automatic transmission control device according to the present invention, and FIG.
The figure is a flowchart showing a shift control method, and FIGS. 3 and 4 are explanatory diagrams showing the vibration state of the steel ball in the detent groove. 1...Shift actuator, 1a...Stepped cylinder, 1b...First piston, 1c...Second
Piston, 1d... Piston rod, 1e...
Shift lever, 1f, 1g... Oil chamber, 2, 3...
Supply pressure valve, 4... Hydraulic source, 5, 6... Exhaust pressure valve, 7... Tank, 8... Shift fork shaft, 9... Shift fork, 10... Sleeve, 11... Insert, 12... Block ring, 13...Gear, 14...Day tent groove, 15
... Spring, 16 ... Steel ball, 17 ... Stroke sensor, 18 ... Electronic control device, 19 ...
...Day tent mechanism.

Claims (1)

[Claims] 1. A shift actuator that is controlled by a stroke sensor that detects the position of the shift actuator so that its position becomes a target value during gear shifting, and a gear that is mechanically connected to the shift actuator. In a vehicle automatic transmission equipped with a detent mechanism for detent, means is provided for reading a value of a stroke sensor in a depressed state of the detent after hydraulic pressure for driving a shift actuator is released, and the value of the stroke sensor is set to the above-mentioned value. If the shift is closer than the target value, the target value for the next shift is updated to the value of the stroke sensor or a value intermediate between the value of the stroke sensor and the target value. A control device for an automatic transmission characterized by: