JPS61248948A - Hydraulic control device of automatic transmission - Google Patents

Abstract

PURPOSE:To prevent worsening of gear shifting shock, according to the method wherein a means, preventing lengthening of a time lag during kick down in a condition in that gear shifting shock during multistage gear shifting is maintained in an excellent condition, is mounted to the hydraulic control device of an automatic transmission gear. CONSTITUTION:An automatic transmission gear for FF to which the hydraulic control device of an automatic transmission gear is employed includes a torque converter 120 and a gear shifting part 140, which are coaxially situated to an engine 9. The gear shifting part 140 comprises a main transmission gear 160 and an auxiliary transmission gear 180. The hydraulic control device is provided with na means, slowing the releasing timing of the frictional engaging device for high speed stage of the auxiliary transmission gear 180 prevailing when the automatic transmission gear is up-shifted as a result of the main transmission gear 160 being high-gear-shifted and the auxiliary transmission gear 180 being low-gear-shifted; and a means, quickening the release timing of a frictional engaging device for high spees stage of the auxiliary transmission gear 180 prevailing when the automatic transmission gear is down-shifted as a result of the auxiliary transmission gear 180 being low-gear-shifted with an accel pedealled.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a hydraulic control II device for an automatic transmission, and particularly relates to a main transmission that can automatically switch gears depending on at least vehicle speed and engine load, and a sub-transmission that can switch at least between a low speed side and a high speed side. The present invention relates to an improvement in a hydraulic control device for an automatic transmission, which is equipped with a main transmission and a sub-transmission, and achieves multi-stage shifting by shifting the main transmission and the sub-transmission simultaneously or alternately.

[Conventional technology]

With the rapid spread of automatic transmissions for vehicles in recent years, the main transmission, which can automatically change gears in relation to vehicle speed and throttle opening, has a reduction ratio of 1 or less, mainly with the intention of improving fuel efficiency. Many models have been adopted in which a so-called overdrive device is attached in series as an auxiliary transmission. In addition, we focused on the function of an 11-speed transmission that can switch between high and low speeds like an overdrive device, and actively synchronized it with the speed change of the main transmission. There is also already known a device in which a multi-stage speed change of six forward speeds is performed by performing a speed change control such as that shown in FIG. In this way, by arranging the Wj1 transmission, which can switch between high speed and low speed, in series with the main transmission, it is possible to build on existing automatic transmissions, reduce design changes, and achieve manufacturing advantages. However, multi-stage gear shifting can be easily realized, and many advantages can be obtained, such as improved fuel efficiency, improved power performance, and a reduction in the burden on the frictional engagement device by providing multiple gear stages.

[Problems to be solved by the invention]

However, in such an automatic transmission that achieves multi-speed shifting by shifting the main transmission and the sub-transmission simultaneously or alternately, for example, as shown in FIG.
By shifting the main transmission to a high gear and shifting the auxiliary transmission to a low gear, such as from a gear to a third gear or from a fourth gear to a fifth gear, the entire automatic transmission is shifted. There may be cases of upshifting, but in this case,
There is a problem in that when the acting force on the sub-transmission side is suddenly released, a large shift shock occurs. In order to deal with this problem, it is necessary to make the low gear shift of the auxiliary transmission gentler in such cases, that is, to slow down the speed at which the hydraulic servo mechanism for high gear of the auxiliary transmission releases. As a means used in such cases, it is common to provide a restriction (orifice) in the oil passage. However, providing an orifice not only lengthens the time lag when the accelerator is depressed and the auxiliary transmission shifts to O-gear (so-called kickdown), but also worsens the shift shock at that time. occurs.

[Purpose of the invention]

The present invention has been made in view of such conventional problems, and while maintaining good shift shock during multi-speed shifting, does not increase the time lag at kickdown and worsens the shift shock. It is an object of the present invention to provide a hydraulic III-m device with automatic shift depth that does not cause the transmission to occur. (Means for Solving the Problems) The present invention provides a main transmission capable of automatically switching gears depending on at least vehicle speed and engine load, and a sub-transmission capable of switching at least a low speed side and a high speed side. The hydraulic control device for an automatic transmission is configured to achieve multi-speed shifting by simultaneously or alternately shifting the main transmission and the auxiliary transmission, wherein the main transmission shifts to a high gear;
and means for slowing the release timing of the high speed friction engagement device of the auxiliary transmission when the automatic transmission is upshifted by shifting the auxiliary transmission to a low gear;
When the automatic transmission downshifts when the accelerator is depressed and the auxiliary transmission shifts to a low gear, the automatic transmission speeds up the release timing of the high-speed friction engagement device of the auxiliary transmission. The above objectives have been achieved. Further, in an embodiment of the present invention, the degree to which the release timing is made gradual is determined according to at least one of vehicle speed, engine load, and accelerator depression speed,
For example, it is possible to improve the shift shock in a more detailed manner depending on the driving condition of the vehicle, such as improving the shift shock during partial down.

[Effect]

In the present invention, instead of simply slowing down the release timing of the high-speed friction engagement device of the auxiliary transmission, the release timing is made faster when the accelerator is depressed and the auxiliary transmission shifts to a low gear. As a result, the shock during multi-speed shifting can be maintained well, the time lag during kickdown can be shortened, and the shift shock during kickdown can be prevented from worsening.

【Example】

Embodiments of the present invention will be described in detail below based on the drawings. FIG. 2 is a skeleton diagram of an FF (front engine/front drive) automatic transmission to which the present invention is applied. This automatic transmission includes a torque converter 120 and a transmission section 140 that are provided coaxially with the engine 9.
has. The transmission section 140 includes main transmissions 1160, ! :
, :(7) A sub-transmission 180 connected in series to the output shaft of the main one-speed gear 160. The main transmission 160 is an underdrive device here, and has three forward speeds, and the auxiliary transmission 180 is an overdrive device, and has two forward speeds, a low speed speed with a reduction ratio of 1 and a high speed speed with overdrive. have. The main transmission 160 has a common sun gear 16
1, ring gear t162a, 162b 1 planetary binion 164a, 164b, and carrier 166
It is equipped with two rows of planetary gears on the front side and rear side consisting of clutches CI and 02N, respectively.
Brake Bl, B2.83, and one-way clutch F+,
The rotation is controlled by t"z. On the other hand, the sub-transmission 180 includes a planetary gear device consisting of a sun gear 181, a ring gear 182, a planetary pinion 184, and a carrier 186, and a clutch Co s brake B o z
The rotation is controlled by a one-way clutch Fo. Since the specific coupling structure of the main transmission 160, the sub-transmission 1180, and each II frictional engagement device is well known, a skeleton diagram thereof is only shown in FIG. 2, and detailed explanation thereof will be omitted. In addition, in this automatic transmission, each element such as the brake and clutch is set at 1TI as shown in Fig. 3 to achieve each gear.
The main transmission 160 and the sub-transmission 180 are shifted into gear as shown in FIG. FIG. 1 is a partial diagram of a hydraulic control circuit for controlling the automatic transmission. The oil pump 10 sucks oil in the oil reservoir 1, pressurizes it, and protrudes. Other hydraulic liIIwJ circuit 12
includes various pressure regulating valves such as a primary regulator valve, and a shift valve that controls the speed change of the main transmission 160, and since the configuration and operation of these are well known, a description thereof will be omitted. The 3-4 shift valve 14 is a valve that controls the speed change of the auxiliary transmission 180, and the state on the left side of the drawing is the boat 14.
d and the boat 14e are in communication and line pressure is supplied to the clutch Go, so the clutch CO is engaged and the sub-transmission is placed in a low gear (see FIG. 4). Also, 3-4 shift valve 1
4 is in the state on the right side of the drawing, boat 14d and boat 1
4c and line pressure is supplied to the brake Bo, so the brake Bo is engaged and the auxiliary transmission 180 becomes a high speed gear. The states and switching of the right side and left side of the 3-4 shift valve 14 in the figure are ON-OFF of an electromagnetic solenoid valve (not shown) that is driven by instructions from the microcomputer 24 inputted with throttle opening, vehicle speed, etc.
This is done depending on whether or not the control hydraulic pressure is applied to the boat 14a. The So release control solenoid 16 is provided in the BO drain oil path from the boat 14b of the 3-4 shift valve 14, and includes a valve body 161), a solenoid 16C1
It is composed of a spring 16d that pushes back the valve body 16b. Solenoid 16C is microcomputer 24
controlled by electrical signals from When the So release control solenoid 16 is in the OFF state, the boat 16a is closed, so the drain of the brake Bo is throttled by the orifice 18, and the brake Bo is released smoothly. Also, Bo release control solenoid 1
6 is in the ON state, the boat 16a is opened, so
Most of the drain from the brake Bo is drained from the drain boat 16e of the So release control solenoid 16, so that the brake Bo can be released quickly. FIG. 5 shows the characteristics when the automatic transmission performs an upshift from second speed to third speed. In this shift, the main transmission 160 shifts to a high gear and the sub-transmission 180 shifts to a low gear. Therefore, in order to improve the shift shock, it is necessary to make the low gear shift of the sub-transmission 180 gradual. Therefore, it is necessary to maintain an appropriate residual pressure in the Bo hydraulic pressure by means such as an orifice. However, if the 8o oil pressure is left at the orifice alone, not only will the time lag during kickdown become longer, but a new problem will arise in that the shift shock during kickdown will become worse. In this example, in order to prevent such problems,
When the main transmission 160 shifts to a high gear and the auxiliary transmission 180 shifts to a low gear (the automatic transmission as a whole shifts up), the BO oil pressure is left in the orifice (slowly released). At the time of kickdown, the Bo oil pressure is quickly drained to prevent an increase in time lag and worsening of shift shock at the time of kickdown. FIG. 6 shows the shift characteristics during kickdown (corresponding to shifting from 6th gear to 5th gear in the entire automatic transmission) according to this embodiment. After time t0 on the ship, the 3-4 shift pulp 14 is in the state on the right side of the drawing in FIG. is engaged, and the auxiliary transmission 180 is on the high gear side. time

When it reaches 0, the boat 14a of the 3-4 shift pulp 14
The tIi control oil pressure that was operating at that time is turned off, and the 3-4 shift pulp 14 changes to the state shown on the left side of the drawing. Therefore,
Boat 14d and boat 14e communicate with each other, line pressure is supplied to clutch Co, and boat 14c and boat 14b communicate with each other, so So hydraulic pressure is drained.
At this time, the Bo release control solenoid 16 is set to the ON state by the microcomputer 24, so that the brake Bo drains quickly and the Bo release control solenoid 16 is turned on by the microcomputer 24.
is released faster. At time t1, the sub-transmission 180
Since the input shaft rotational speed of the one-way latch Fo increases to the synchronous rotation of the one-way latch Fo, the sub-shift 11180 becomes a low gear state. FIG. 7 is a control flowchart of this embodiment. First, in step 30, flag F and timer T are reset as initialization. In step 32, the designated gear position is calculated from the vehicle speed, intake throttle opening degree, etc. If there is no gear change, the determination is F-0 in step 34 and No in step 36, and the Bo release control solenoid 16 is turned off (step 38). However, if the nJ gear shift fi 180 is downshifted by pressing the accelerator, YES is selected in step 36.
Since the determination is made, the Bo release control solenoid 16 is turned on (step 40), and step 4
After flag F is set to 1 in step 2, step 4
At 4, the timer starts counting. In step 54, the shift control solenoid valve is driven and controlled based on the instructed gear position determined in the main routine in step 32. When the auxiliary transmission 180 is kicked down, the flag F is set to 1, so the determination is F-1 in step 34, and the timer value and predetermined time Ta are determined in step 46.
If T<Ta, that is, if the predetermined time Ta has not elapsed, nothing is done (step 54).
), if T≧Ta, turn off the Bo release control solenoid 16 (step 48),
Reset flag F1 and timer T (step 50
．． 52). In the above embodiment, the Bo release control solenoid 16 is set to O during a downshift in a low speed range, for example.
By using FF, it is possible to improve the shift shock during so-called partial down. Such control is B. The timer Ta of the release control solenoid 16
setting time or ON/OFF duty ratio,
This can be done by making it variable depending on the lI speed, throttle opening, or accelerator depression speed. Effects of the Invention As explained above, according to the present invention, the shift shock during multi-speed shifting can be avoided, especially when the entire automatic transmission is upshifted due to the main transmission shifting to a high gear and the auxiliary transmission shifting to a low gear. This reduces the time lag during kickdown, which is achieved by the auxiliary transmission shifting to a low gear, while maintaining good gear shift shock.
An excellent effect can be obtained in that the shift shock at the time of kickdown can be prevented from worsening.

[Brief explanation of drawings]

FIG. 1 is a hydraulic control circuit diagram showing a part of an embodiment of a hydraulic control device for a vehicle automatic transmission according to the present invention, and FIG. 2 is a skeleton diagram of a vehicle automatic transmission to which the above embodiment is applied. 3 is a diagram showing the engagement and combination state of the frictional engagement device of the automatic transmission, and FIG. 4 is a diagram showing the gear shift combination of the main transmission and the auxiliary transmission. Figure 5 is a shift characteristic diagram when the entire automatic transmission shifts from 2nd gear to 3rd gear, and Figure 6 shows the shift characteristics when the entire automatic transmission downshifts from 6th gear to 5th gear. Shift characteristic diagram,
FIG. 7 is a flowchart showing the control routine used in the above embodiment. 160... Main transmission, 180... Sub-transmission,
14...3-4 shift valve, 16...Bo release control solenoid, 18
...orifice, 24...microcomputer.

Claims (2)

[Claims] (1) At least a main transmission capable of automatically switching gears in relation to vehicle speed and engine load, and an auxiliary transmission capable of switching at least a low speed side and a high speed side, the main transmission and the auxiliary transmission In the hydraulic control device for an automatic transmission, the automatic transmission achieves multi-speed shifting by simultaneously or alternately shifting the main transmission to a high gear and the auxiliary transmission to a low gear. A means for slowing the release timing of a high-speed friction engagement device of an auxiliary transmission when upshifting, and a means for slowing down the automatic transmission when the accelerator is depressed and the auxiliary transmission shifts to a low gear. A hydraulic control device for an automatic transmission, comprising: means for speeding up the release timing of a high-speed friction engagement device of the auxiliary transmission. (2) The degree to which the release timing is made gradual;
The hydraulic control device for an automatic transmission according to claim 1, wherein the hydraulic pressure control device is determined according to at least one of vehicle speed, engine load, and accelerator depression speed.