JP2613036B2 - Shift control device for electronically controlled automatic transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a shift control device for an electronically controlled automatic transmission that controls a shift by driving an actuator with fluid pressure.

(Prior Art) In recent years, automatic transmissions in which a transmission of a vehicle is controlled by an electronic control unit have been developed.

In such an electronically controlled automatic transmission, a solenoid valve that supplies fluid pressure to an actuator is selectively opened and closed by a command from an electronic control device to which a signal such as a vehicle speed or an accelerator pedal depression amount is input, and shift and shift are performed. The shift actuator and the gear select operation are performed by operating the select actuator.

FIG. 6 is a schematic configuration diagram of an example in which a double piston type shift actuator is used and hydraulic pressure is used as a fluid pressure. In this case, the shift actuator 1
It consists of a cylinder part 1a and a piston part 1b, and the piston part 1b
Has a piston rod 1b ₁ having a diameter φA, an enlarged portion 1b ₂ having a diameter φB, and two ring portions 1b ₄ having an outer diameter φD and an inner diameter φB. Therefore, in this case, each thrust is as follows.

Here, P is a hydraulic pressure.

Under such conditions, it is necessary to satisfy the following conditions. That is, (1) F ₁ ′ (F ₂ ′) does not exceed the allowable shift force of the shift actuator, works within the allowable shift time, and (2) F ₃ ′ (F ₄ ′) is the thrust that can be disengaged. , Etc.

The shift actuator 1 operates as follows. First, when only the solenoid valve V ₁ is being turned on, it is opened,
Hydraulic moved by pressing with a force of F ₁ 'the働Ra-out piston rod 1b to the left of enlarged portion 1b ₂ right, taking the R-side position. Further, when only the solenoid valve V ₂ is turned on, the hydraulic pressure moves to press with a force of F ₂ 'projections 1b of the piston rod to the right, taking the L-side position.

When the solenoid valves V ₁ and V ₂ are turned on at the same time, the force of F ₃ ′ and F ₄ ′ acts on the two rings 1 b ₄ from the left and right, and the enlarged portion 1 b ₂ sandwiched between the rings 1 b ₄ is formed. Hold in neutral position.

(Problems to be Solved by the Invention) In the electronically controlled automatic transmission, the gear shift is controlled by simply supplying hydraulic pressure or air pressure to the cylinder by simply turning on / off the solenoid valve when the gear is engaged or disengaged. However, when a pneumatic cylinder is used, the air has a spring action because it is a compressible fluid, and the synchro mechanism may be damaged because a large amount of air is supplied from a minute gap. is there. For example, when shifting gears up or down, the rotation time before and after gear shifting is large, so the synchro time is long, but at the time of synchro, the thrust is maximized and the piston stops, so in simple on / off control of the solenoid valve, Air is injected into the cylinder, and the pressure in the cylinder changes to the supply pressure. For this reason, after synchronization, the piston shifts at a high speed due to the air spring action and a large amount of air injection due to the pneumatic pressure stored in the cylinder.
At this time, on the gear side, the sleeve collides with the dog teeth of the gear at a high speed, and the dog teeth may be damaged.

To prevent such damage to the synchro mechanism, the cylinder thrust is reduced to cover the durability of the transmission.However, the low thrust increases the downshifting time, causing the gear to shift during cold temperatures or downhill roads. As the time becomes longer, the situation in which the clutch is disengaged continues for a long time, and there is a problem in that the safety during running of the vehicle is impaired.

In order to prevent damage to the synchro mechanism as described above,
For example, a control device for a transmission proposed in Japanese Patent Application Laid-Open No. 60-84448 is known, but it is sufficient for a request to shorten the shift time and improve the performance of the vehicle while maintaining the durability of the transmission. Could not respond to.

SUMMARY OF THE INVENTION The present invention provides a shift control device for an electronically controlled automatic transmission which aims to solve the problems of the related art.

(Means for Solving the Problems) A shift control device for an electronically controlled automatic transmission according to the present invention controls shifts of an electronically controlled automatic transmission that drives a transmission by controlling a transmission actuator in accordance with a command from the electronic control device. In the apparatus, a transmission having a synchronization mechanism, a means for detecting an operation state of the synchronization mechanism of the transmission, and a cylinder fluid pressure of a transmission actuator in a state in which the completion of the operation of the synchronization mechanism is detected by the means during a shift operation. , A shift completion detecting means for detecting the completion of a shift operation, and a fluid pressure of the cylinder being raised from the set value in a state where a signal of the shift completion detecting means is not detected within a predetermined time. Means for forcibly completing the gear shifting operation to the target gear.

(Operation) In the present invention, in the shift operation of the transmission, a means for reducing the cylinder air pressure of the shift actuator to a set value or less after detecting completion of synchronization,
The means for forcibly completing the shift within the set time is provided, so that even when the thrust is large, the dog teeth of the synchro mechanism can be prevented from being damaged, and both the characteristics of transmission durability and vehicle running performance can be secured. The shift can be completed even when the current shift thrust lacks the thrust due to high viscosity of the gear oil at a low temperature or the like.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a shift control device for an electronically controlled automatic transmission according to the present invention.

In the figure, reference numeral 1 denotes a shift actuator for performing a shift operation of the transmission, which is configured to be able to stop at three positions, which is the same as that described in FIG. The piston rod end 1b ₁ of the piston 1b and shift shaft 1e of the transmission is mounted, the piston moves up and down depending on the magnitude of the fluid pressure acting on the cylinder 1a, the gear stage 1-3 5-speed side, the neutral N _1, N _2, N ₃ side, R-2
It is switched to the -4th speed side. P ₁ and P ₂ are sensors for detecting the air pressure of the cylinder as shown in FIG. 2, and a switch operated by the air pressure may be attached.

V ₁ and V ₂ are three-port solenoid valves for controlling the supply of working fluid using the pump 3 as a fluid pressure source to the fluid chambers, respectively, and are performed by instructions from the electronic control unit 2.

Reference numeral 4 denotes a select actuator for performing a select operation of the transmission.
It can stop at a position. This is a stepped cylinder 4a,
It comprises a first piston 4b, a cylindrical second piston 4c, a piston rod 4d, and a select shaft 4e, and the stepped cylinder 4a has fluid chambers 4f, 4g at both ends. And both fluid chambers 4
If fluid pressure acts on f and 4g without a response difference, piston rod 4d
Becomes neutral, and when fluid pressure acts only on the fluid chamber 4f
When fluid pressure acts only on the fluid chamber 4g in the N3 direction, the select shaft 4e is driven in the N1 direction.

V ₃ and V ₄ are three-port solenoid valves, and a fluid chamber 4 according to a command from the electronic control unit 2 for the working fluid from the pump 2.
f, 4g to control the operation of the select actuator 4.

5 is a stroke sensor for detecting the shift position of the shift shaft 1e, 6 is a position switch for detecting the select position of the select shaft 4e, and each detected signal is input to the electronic control unit 3 and is determined by a combination of these signals. ,
The shifted gear position is detected.

V ₅ is a normally closed solenoid valve of the two-port, connected to the outlet of the pump 3, and supplies the four solenoid valves V _1, V _2, V _3, V ₄ to the working fluid.

The electronic control unit 2 is constituted by a microcomputer, and has a central processing unit, various memories, and an input / output device. In addition to transmitting signals from the stroke sensor 5 and the position switch 6, a clutch sensor for detecting the operation of a clutch (not shown), an accelerator sensor for detecting the amount of depression of an accelerator pedal, a vehicle speed sensor, and a select position of a select lever are selected. is input various detection signals from a select sensor for detecting is configured to control such the various solenoid valves V ₁ ~V ₅ and not shown clutch actuator based on the detection signal.

Reference numeral 7 denotes a check valve provided in a working fluid supply path to the select actuator, which prevents air from flowing into the select actuator in order to exert an air pressure restricting effect.

Further, as shown in FIG. 3, the transmission is provided with an input shaft sensor (TMN) for detecting the transmission top gear rotational speed and a vehicle speed sensor.

Next, characteristics of the transmission according to the present invention will be described with reference to the characteristic diagrams of FIGS. 4 (a) to 4 (c).

FIG. 4 (a) shows the characteristic when the vertical axis represents the value detected by the transmission shift stroke sensor 5, that is, the gear stroke, and the horizontal axis represents time.
biting dog teeth is performed between t ₂ -t _3.

Figure 4 (b) is the vertical axis represents the value of the input shaft sensor (TMN), is a characteristic diagram when the horizontal axis and the time axis, synchronous operation is started at time t _1, at time t ₂ The synchronization operation ends.

FIG. 4 (c) shows a characteristic in which the vertical axis represents the cylinder pressure by the air pressure sensors P ₁ and P ₂ and the horizontal axis represents the time axis. The cylinder pressure a is the limit of the limit that does not adversely affect the dog teeth. Set to air pressure. The specific operation of the present invention will be described below with reference to the control flowchart of FIG.

At the beginning of the transmission shift, reads a shift instruction to a predetermined gear stage at step P _1, performs the clutch disconnection control in step P _2. Then, performs gear disengagement and opening control of the shift electromagnetic valves V _1, V ₂ at step P _3, then perform the opening control of the select solenoid valve V ₃ and V ₄ in step P _4, shift And the select actuator is held at that shift speed.

At step P _5, performs closing control of the shift solenoid valve V ₁ or V _2, to operate the shift actuator. next,
In step P _6, the value of the input shaft sensor (TMN), check whether (dTMN / dT = 0) the operation determined by synchro operation is completed, the determination processing in Step P ₅ If NO returning to, if the determination is YES, at followed by step P _7, the value of the TMN is, when the vehicle speed v, gear to be gear ratio G, the coefficient a K, TMN =
v × G × K, a whether, i.e., checks whether the rotational speed of the vehicle speed and the input shaft are the same, if the decision is NO, returns again to step P ₅ following process, the determination is YES if, the process proceeds to step P _8. Processing in step P ₇ is to determine whether synchronous starting point or synchro completion point.

At step P _8, the cylinder pressure by the air pressure sensor P _1, P ₂ is, to check whether the relation of P ₁ or P ₂ <a. Here, a is the set air pressure (kg / cm ² ) described with reference to FIG. 4 (c). In this process, the cylinder air pressure after the end of the synchronization is within the cylinder air pressure that does not adversely affect the dog teeth such as breakage. Check if there is.
If the determination is YES, the process proceeds to the next processing step P _10, decision closes the solenoid valve V ₅ at step P ₉ If NO, the circular shifting pneumatically and Tsu in the cylinder, sudden shifts So that it does not

In step P _10, checks whether the shift has been completed by the stroke sensor 5, if no shift has been completed, before or after a lapse of shift time αsec levels without the vehicle running on the problem at step P ₁₁ Check
If before the elapse process returns to Step P _10, if after performs opening control of the solenoid valve V ₅ in step P _12, to perform a forced shift. If you have not yet elapsed α seconds, it does not perform the opening of the electromagnetic valve V ₅ is.

If the shift completion is confirmed in step P _10, the solenoid valve V ₅ are closed in the next step P _13, Step P ₁₄ by the clutch in contact with, followed by the step P ₁₅ in the shift electromagnetic valve V ₁ or V Close ₂ and select solenoid valve V ₃ or V ₄ on select side in step _16.
To close. Finally return to the original state by the solenoid valve V ₅ to open in step P _17.

As mentioned above, although one Example of this invention was described, various deformation | transformation are possible within the range of the meaning of this invention, and these are not excluded from the scope of this invention.

(Effects of the Invention) As described above, according to the present invention, when the completion of transmission synchronization is detected, means for setting the cylinder air pressure of the shift actuator to a set value or less,
A means for forcibly completing the shift within the set time is provided, so that it is possible to avoid a sudden shift, prevent the dog teeth from being damaged even if the thrust is increased at the time of the shift, and to reduce the gear oil at a low temperature or the like. The gear shift can be completed even when the current shift thrust is insufficient due to reasons such as high viscosity.

[Brief description of the drawings]

FIG. 1 is a block diagram of the configuration of the present invention, FIGS. 2, 3 are explanatory diagrams, FIGS. 4 (a) to (c) are characteristic diagrams, FIG. 5 is a flowchart, and FIG. It is a block diagram. 1 shift actuator, 2 electronic control unit, 3
...... Pump, 4 ... Select actuator, 5 ... Stroke sensor, 6 ... Position switch, 7 ... Check valve.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Reference number in the agency FI Technical display location F16H 61/08 F16H 61/08 61/10 61/10 61/34 61/34 63/00 63/00 63 / 02 63/02 63/20 63/20

Claims (1)

(57) [Claims] 1. A transmission control device for an electronically controlled automatic transmission that drives a transmission by controlling a transmission actuator in accordance with a command from an electronic control device, comprising: a transmission having a synchronization mechanism; and an operation state of the synchronization mechanism of the transmission. Means for detecting the completion of the operation of the synchronizing mechanism during the shifting operation, means for setting the cylinder fluid pressure of the transmission actuator to a set value or less in a state where the completion of the operation of the synchronization mechanism is detected by the means, Means for raising the fluid pressure of the cylinder above the set value in a state where the signal of the shift completion detecting means is not detected within a predetermined time, and forcibly completing the shift operation to the target gear. A shift control device for an electronically controlled automatic transmission.