JPS61252949A - Select shock reducer for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the select shock by performing the feedback control such that the output torque from automatic transmission will increase with specific rate necessary in view point of select shock prevention. CONSTITUTION:Pressure regulating means (i) is controlled on the basis of the outputs from output torque detecting means (g) for detecting the output torque of the output shaft (c) and torque increasing rate setting means (h) for setting a target increase speed to be required for prevention of select of the output torque such that the output torque of the output shaft of automatic transmission will increase with the target increase rate upon detection of switching of range through range switching detection means (f).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for reducing select shock when switching to a travel range of an automatic transmission.

(Prior Art) Generally, automatic transmissions are automatically shifted from a parking (P) or neutral (N) range to a driving range, i.e., a forward automatic transmission (D) range or a reverse (R) range, by turning a manual valve when the driver desires to drive. When the vehicle starts, the vehicle can start by hydraulically operating the corresponding starting friction element, and by selectively hydraulically operating the post-starting friction element, it is possible to shift to other gears. It is common to configure it like this.

By the way, when switching to the driving range, the friction element for starting is hydraulically activated from its inactive state and starts transmitting engine power to the drive wheels of a stopped vehicle, so there is a fluid coupling such as a torque converter in the engine power transmission system. Then, when the hydraulic pressure of the starting friction element suddenly increases, the transmission of power to the drive wheels becomes rapid, causing a so-called select shock.

For this reason, as described in Japanese Patent Application Laid-Open No. 59-13156, a solenoid valve that controls the increase in the hydraulic pressure of the starting friction element is chopped a predetermined number of times, so that the hydraulic pressure increases with a predetermined time gradient. An eggplant technology was proposed.

(Problems to be Solved by the Invention) However, in this conventional technology, since the hydraulic pressure is controlled in an open manner, the rate of increase is subject to manufacturing variations in the automatic transmission, hydraulic oil temperature (viscosity), It varies depending on changes in the electromagnetic valve drive voltage, etc., and it is difficult to say that it is always appropriate, and it has not always been possible to reliably reduce the select shock.

(Means for Solving the Problems) The present invention has a configuration that prevents select shock by feedback controlling the hydraulic pressure so that the output torque of the automatic transmission increases at a predetermined speed required to prevent select shock. This is an attempt to solve the above-mentioned problem, and as shown in the concept in Fig.
An automatic transmission e equipped with a starting friction element d capable of transmitting power from an engine (b) to an outfoot shaft c, comprising: a range switching detection means f for detecting the range switching; and an output torque of the output shaft C. output torque detection means g for detecting the output torque, torque increase speed setting means for setting a target increase speed required to prevent select shock of the output torque, and the output torque increases at the target increase speed when changing the range. The present invention is characterized in that it includes a pressure regulating means i for increasing the working oil pressure of the starting friction element d.

(Function) The pressure regulating means 1 causes the output torque of the output shaft C detected by the means g to increase at a speed set by the means when the means f detects a change to the driving range of the automatic transmission e. In this way, the hydraulic pressure of the starting friction element d is increased.

For this reason, the hydraulic pressure is feedback-controlled, and the output torque is constantly increased at the target speed without being affected by manufacturing variations in the automatic transmission, hydraulic oil temperature, or changes in the pressure regulating means drive voltage. This makes it possible to always achieve the desired selective shock reduction effect.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Figure 2 shows an embodiment of the selective shock reduction device of the present invention, in which 1 is an engine, 2 is a torque converter (hydraulic coupling) of an automatic transmission, and 3 is a hydraulically operated engine that continues to be operated in the travel range of the automatic transmission. The clutch serves as a starting friction element. The power from the engine l is its crankshaft 1
a to the torque converter 2, and this torque converter outputs the engine power to the clutch 3 via the output shaft 2a.
Enter. The clutch 3 includes a clutch housing 3a,
It consists of a clutch pack in which a drive plate 3b is drivingly connected to this and a driven plate 3c that is drivingly connected to an output shaft 4 of the own I transmission, and a clutch piston 3d, and supplies hydraulic pressure PC to a chamber 3e. When this happens, the clutch 3 is activated and transmits the engine power reaching the shaft 2a to the output shaft 4.
The vehicle shall be running.

The working oil pressure (clutch pressure) PC is created by regulating the line pressure PL supplied from the circuit 5 in the travel range of the automatic transmission with the control valve 6, and is supplied to the chamber 3e via the circuit 7. The control valve 6 includes a spool 6a, which is biased to the left in the figure by a spring 6b and biased in the opposite direction by a control pressure Ps in a chamber 6C. The spool 6a strokes to a position where these applying forces are balanced, and when moving to the left from the illustrated position, the circuit 7 is connected to the circuit 5 to increase the clutch pressure PC.
When moving to the right, the circuit 7 is connected to the drain port 8 to lower the clutch pressure PC.

In order to create the control pressure P, the chamber 6c is connected to the branch circuit 9 and the circuit 5 to receive the replenishment of the line pressure Pt.
The pressure is discharged from the drain port 10, and a solenoid valve 11 is provided opposite the drain port 10. When the solenoid lla is deenergized, the solenoid valve 11 sets the plunger llb in a free state to allow exhaust pressure from the drain port 10, and the solenoid lla
It is assumed that when the plunger a is energized, the plunger llb protrudes and closes the drain port 10. In addition, the solenoid valve solenoid lla
The duty of energization is controlled by the controller 12,
As the on-time width increases during a certain cycle, the solenoid valve 11 decreases the opening degree of the drain port 10 to increase the control pressure P.
, as shown in Fig. 4.As the control pressure P increases,
The spool 6a moves to the right from the left limit position while compressing the spring 6b, and is finally displaced further to the right from the position shown in the figure, so that the clutch pressure P increases as the electromagnetic valve drive duty increases, as shown in Fig. 4. lowered.

The controller 12 receives a signal from the idle switch 13 that closes when the accelerator pedal of the engine 1 is released! ,
Signal R1 from the inhibitor switch 14 which closes the clutch 3 in the driving range in which it should be operated; a signal from the vehicle speed sensor 15 which detects the vehicle speed from the rotational speed of the output shaft 4; and a torque sensor which detects the output torque T0 from the outshaft 4. The signal from 16 is manually transmitted.

It is assumed that the controller 12 executes the control program shown in FIG. 3 based on the human power information to control the solenoid valve 11 on a duty basis. This control program is started when the engine 1 is started, and various initial values are set for initial control in step 20 at the start. In the next step 21, the signals I and R are read, and in the next step 22, the timer T is set.
, is 0 or not. This timer T+ is used to perform processing at regular intervals, and when the timer T+ reaches 0, the count value set at step 23 is set at step 2.
The control is returned to step 21 until the value becomes 0 again due to the decrement at step 4.

In step 25 following step 23, the output torque T is determined.

and vehicle speed V, and in the next step 26 v=0.
In other words, it is determined whether the vehicle is stopped or running. If it is running, set the duty to 0% in step 27, and step 28
Then, a timer T2, which will be described later, is set to 0, a duty of 0% is output at step 29, and the control returns to step 21. As is clear from Fig. 4, the duty O% is the clutch pressure P
Set C to the same maximum value as line pressure PL, fully activate clutch 3, and enable running.

If it is determined in step 26 that the vehicle is stopped, it is determined in step 30 whether or not it is in the driving range based on the read signal R, and if it is not in the driving range, in step 31 a timer
After resetting 2 to O, the control returns to step 21,
If the vehicle is in the travel range, it is determined in step 32 whether or not the accelerator pedal has been released from the read signal I, that is, whether or not the driver has not performed a starting operation. If a start operation is being performed, steps 27, 28 and 29 are executed to operate the clutch 3 and enable the start.

If it is determined in step 32 that the start operation has not been performed,
In step 33, timer T2 is incremented. Since this timer T2 is reset in step 27.31 and incremented in step 33, it measures the duration of the stopped state in the driving range, and the table data of the target output torque T0' regarding this time is stored in, for example, the fifth Leave it as shown in the figure. Note that the time gradient of this target output torque T0' is set so as to be required to prevent select shock of the automatic transmission. In the next step 34, from the count value of the timer T2 incremented in step 33, the target output torque T0' is looked up based on the table data corresponding to FIG. The deviation ΔTo=To−To′ from To' is calculated.

In step 36, it is checked whether the deviation ΔT0 is 0, positive, or negative. If ΔT0 = 0, that is, T, = T,
By holding ty (OLD) as it is and outputting it in step 29, the output torque T0 is kept in a state in agreement with the target value T0'. If ΔT0>0, that is, if the output torque T0 is larger than the target value T0', O
l ← Loi (0 opening) + Ki - ΔT.

口uty4- [)t 10K, ・ΔT0 However, Dl: Duty integral calculation value Di (OLD): Previous value of duty integral calculation, : Integral constant KP: Proportionality constant PI calculation in the direction of increasing output duty. By outputting this in step 29, the clutch pressure PC is lowered, as is clear from FIG. When the clutch pressure decreases, the output torque To also decreases, as shown in FIG. is the target value T. ' can be brought to '. Δ
T. If <0, that is, the output torque T. is the target value T. If smaller than
T0outy← Low i-ni, ・ΔT.

By calculating Pl in the direction of decreasing the output duty and outputting it in step 29, the clutch pressure PC is increased as is clear from FIG. When the clutch pressure increases, the output torque To also increases as shown in FIG. is the target value T. ' can be brought to

According to the above PI sub-control, when the clutch pressure PC is in the stopped state in the driving range, the output torque T0 is the target output torque T shown in FIG. Feedback control is performed so that the increase has the same time gradient as ', and it is always ensured that the clutch pressure PC does not rise too quickly when switching to the driving range and causes a select shock without being affected by external disturbances. can be prevented.

(Effects of the Invention) As described above, the select shock reducing device of the present invention changes the working oil pressure (clutch pressure PC) of the starting friction element (clutch 3 in the illustrated example) to the output torque T when switching to the driving range. is the target speed required to prevent select shock (
Feedback control (in the illustrated example, PI sub-control is configured to increase the time gradient in Fig. 5) so that manufacturing variations in automatic transmissions and hydraulic oil temperature and viscosity increase
The operating oil pressure can be raised at all times at a speed that does not cause select shock, regardless of changes in the drive voltage of the pressure regulating means (in the illustrated example, the drive voltage of solenoid lla), and the select shock is always reduced as intended. It is possible to achieve the effect.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the selective shock reduction device of the present invention, Fig. 2 is a system diagram showing an embodiment of the inventive device, Fig. 3 is a flowchart showing a control program of the controller in the same example, and Fig. 4 is the same. FIG. 5 is a diagram illustrating the change characteristics of the control pressure, clutch pressure, and transmission output torque with respect to the duty output by the example controller. FIG. a...Fluid coupling b...Engine C...
Output shaft d...Friction element for starting e...Automatic transmission f...
・Range switching detection means g...Output torque detection means h...Torque increase speed setting means l...Pressure regulating means l...Engine 2...
Torque converter (fluid coupling) 3...Clutch (frictional element for starting) 4...Output shaft 5-11...Pressure regulating means (6...control valve, 11...
Solenoid valve) PC...Clutch pressure (operating oil pressure) 12...Controller 13...Idle switch 14...Inhibitor switch (range switching detection means) 15...Vehicle speed sensor

Claims (1)

[Claims] 1. In an automatic transmission equipped with a starting friction element that is hydraulically actuated upon switching to a travel range and is capable of transmitting engine power from a fluid coupling to an output shaft, the range detects the range switching. switching detection means; output torque detection means for detecting the output torque of the output shaft; torque increase speed setting means for setting a target increase speed required to prevent select shock of the output torque; A select shock reduction device for an automatic transmission, comprising pressure regulating means for increasing the working oil pressure of the starting friction element so that the torque increases at the target increase speed.