JPH0328571A - Hydraulic pressure controller for automatic transmission - Google Patents

Abstract

PURPOSE:To perform engagement of friction elements in a short period of time and reduce shocks by creating a precharge pressure with sudden rise and fall of working fluid pressure at the time of shifting from the neutral to the drive range and creating a capacity control pressure of the friction elements by gradually increasing pressure from the lowered pressure. CONSTITUTION:Precharge pressure control means 210 of a control unit 10 outputs a signal based on a range shifting signal of a selection lever 24 to line pressure control means 206 so that the line pressure is rapidly raised and lowered temporarily to precharge friction elements. Capacity control pressure control means 212, upon receiving a finish signal of the precharge pressure control means 210, outputs a signal to line pressure control means 106, gradually raises the line pressure, and lowers the line pressure to a normal pressure after the time has passed in which the engagement of the friction elements has been finished. As a result, the engagement of the friction elements is performed in a short period of time and the shocks during the engagement are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hydraulic pressure control device for an automatic transmission, and more particularly, to a hydraulic control device for an automatic transmission that reduces select shock when switching from a neutral range to a driving range. This invention relates to a hydraulic control device.

2. Description of the Related Art Conventional automatic transmissions include, for example, Japanese Patent Application Laid-Open No. 62-62
As disclosed in Publication No. 047, various speed changes are achieved by switching the coupling combination of each component (sun gear, pinion carrier, internal gear) of a plurality of planetary gear sets via a plurality of friction elements. You can now get dan.

For example, a clutch or a brake is used as the above-mentioned friction element, and the engagement or disengagement is performed by hydraulic pressure supplied from a hydraulic pressure supply circuit (control valve). rotating part,
For example, a clutch is connected when a drive plate and a driven plate are crimped and joined together.

Problems to be Solved by the Invention At this time, the drive (D) range is changed from the neutral (N) range to the drive (D) range.
) range, the friction element that is first engaged in the D range, for example, the above-mentioned JP-A-61
In Publication -62047, the low clutch is engaged at l speed in the D range, but if the working fluid pressure (line pressure) is suddenly supplied to the low clutch due to this N→D selection, the engagement of the low clutch may not be completed. Although this is done in a short time, a large engagement shock is generated at this time, which becomes a select shock and significantly deteriorates the ride comfort of the vehicle.

Therefore, if we try to slowly increase the line pressure in order to reduce the shock of engaging the low clutch, the time required to complete the engagement of the low clutch becomes significantly longer, which not only makes it impossible to start smoothly.
There has been a problem in that the low clutch may slip for a long time, resulting in seizure.

In view of such conventional problems, it is an object of the present invention to control the hydraulic pressure at the time of selection so that the friction element is engaged in a short time and with significantly less shock.

Means for Solving the Problems In order to achieve this object, the present invention, as shown in FIG. In an automatic transmission equipped with a hydraulic pressure supply circuit b that supplies working hydraulic pressure to the friction element a, when a range signal is input and the range signal is input to switch from the neutral range to the travel range,
A precharge pressure regulating means C that temporarily raises the working hydraulic pressure mentioned above rapidly and then rapidly lowers it to create a shelf pressure for precharging, and gradually adjusts the working hydraulic pressure from the time when the precharge pressure falls. and a capacity adjustment pressure regulating means d for raising the capacity adjustment pressure of the friction element.

Operation With the above-described structure, the hydraulic pressure control device for an automatic transmission according to the present invention has the advantage that when switching from the neutral range to the driving range, the hydraulic pressure is temporarily increased rapidly by the precharge pressure regulating means C; , by being suddenly descended,
Preparation for engagement of the friction element is quickly carried out, and then the working fluid pressure is gradually increased by the capacity adjustment pressure means d, thereby significantly reducing the shive and y when the friction element is completely engaged. be able to.

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

That is, FIG. 2 is a schematic diagram of a hydraulic pressure control device for an automatic transmission showing one embodiment of the present invention, where I is an automatic transmission, 2 is an engine, and the automatic transmission 1 has gears shown in FIG. 3. A train is built in, and the output rotation of the engine 2 is inputted to the gear train via a torque converter 3.

The power train of the above automatic transmission l includes a front sun gear 12s, a front binion gear 12p, a front internal gear 12i, and a front bracket carrier 1.
2c, and a rear planetary gear set 14 including a rear sun gear 14S, a rear binion gear 14p, a rear internal gear 141, and a rear planetary carrier 14c. arranged in tandem.

Further, as shown in the figure, the power train includes a reverse clutch R/C that connects the input shaft 16 and the front sun gear 12s, a high clutch I/C that connects the input shaft 22 and the front net carrier 12c, and a front Forward clutch F/C that connects the net carrier 12C and rear internal gear 14i, brake band B/B that fixes the front ring gear 125 to the housing side, and low and reverse brake that fixes the front net carrier 12c to the housing side. Friction elements such as L&R/B are provided.

Further, a forward one-way clutch F is provided between the forward clutch F/C and the rear internal gear 14i.
/O・C is provided, and a row one-way clutch I, /0・C is provided between the front net carrier 12c and the housing, and between the front net carrier 12c and the rear internal gear 1/li. An overrun clutch 0.R/C is arranged in parallel with the forward one-way clutch F/O.C.

By the way, in a power train having such a configuration, as shown in Table 1 below, various frictional elements are engaged and released by line pressure as working hydraulic pressure supplied from a hydraulic pressure supply circuit described later. Gears are now available.

In Table I, the O mark in the same table represents the engaged state, and the unmarked state represents the released state.

Further, the forward one-way clutch F/0.C is free when the rear internal gear 14i rotates in the forward direction with respect to the front net carrier 12C, and is locked when the rear internal gear 14i rotates in the reverse direction. 0.C is front branet carrier 1
Free when rotating in the forward direction of 2c, and locked when rotating in the reverse direction.

By the way, the above-mentioned overrun clutch 0・R/C is
Although not shown in the table, the overrun clutch 0-R
By engaging /C, the function of the forward one-way clutch F/O.C is eliminated and the engine brake is activated.

FIG. 4 shows a hydraulic pressure control circuit for controlling the line pressure supplied to each friction element, and each friction element is engaged or released by the control hydraulic pressure supplied from the hydraulic pressure control circuit. .

That is, in the above hydraulic pressure control circuit, the pressure regulator valve 20, the pressure modifier valve 22, the line pressure solenoid 24, the pilot valve 26, the lux converter regulator valve 28 . Lock up control valve 30. Shuttle valve 32, lock-up solenoid 34, manual valve 36, first shift valve 38, second
Shift valve 40, first shift solenoid 42, second shift solenoid 44, forward clutch control valve 4
6.3-2 timing valve 48.4-2 relay valve 50.4
-2 sequence valve 52, I range pressure reducing valve 54. Shuttle valve 56. T-bar run clutch control valve 58
, third shift solenoid 60, overrun clutch pressure reducing valve 62, 2nd speed servo brake pressure accumulator 64,
A 3-speed servo release pressure accumulator 66, a 4-speed servo release pressure accumulator 68 and an Akicomulator control valve 70 are provided.

Each component of the hydraulic pressure control circuit has the relationship shown in the figure, and has the following relationships: the reverse clutch R/C, the high clutch H/C, the forward clutch F/C, and the brake band B.
/B, low and reverse brake L&R/B, overrun clutch 0-R/C, each friction variable and oil bomb O/P are connected to each other. Hydraulic pressure is supplied and stopped to the friction elements, and line pressure as the engagement pressure supplied to each friction element is controlled.

The detailed configuration and function of each structure or component of the above-mentioned hydraulic pressure control circuit is the same as that described in JP-A-62-62047, and detailed explanation thereof will be omitted. .

Incidentally, the above band brake B/B is a band servo B/S.
The band servo B/S is operated by a 2nd speed servo bridging pressure chamber 2S/A and a 3rd speed servo release pressure chamber 3S.
/R and 4-speed servo apply pressure chamber 4S/^,
The bunt brake B/B is engaged by supplying hydraulic pressure to the 2nd speed servo bridle pressure chamber 2S/^, and in this state, the band brake B is engaged by supplying hydraulic pressure to the 3rd speed servo release pressure chamber 3S/R. /B is released, and in this state, hydraulic pressure is supplied to the 4-speed servo apply pressure chamber 4S/A, so that the bunt brake B/B is engaged.

By the way, the switching of the first and second shift valves 38.40 is performed by turning on the first and second shift solenoids 42.44, which are configured as off-drain type solenoid valves.
, OFF, and these first and second shift solemade 42, 44 are turned ON, so that the first and second shift
Pilot pressure is supplied to the shift valves 38, 40 to set the first and second shift valves 38, 40 to the right half position (upper position) in the figure, and the first and second shift solenoids 42, 4
4 is turned off, the first and second shift valves 38
．． The pilot pressure supplied to 40 is drained,
The first and second shift valves 38 and 40 are placed in the left half of the figure (lower position).

As shown in Table 2 below, each gear stage is obtained by switching the first and second shift solenoids 42, 44 ON and OFF.

Table 2 By the way, the switching signals for the first and second shift valves 38 and 40 are determined by the control unit 1 shown in FIG.
The speed change control means 200 built into the vehicle is used to determine the speed change based on the throttle opening signal obtained from the throttle sensor 202 and the vehicle speed signal obtained from the vehicle speed sensor 204. For example, the shift schedule is determined based on the vehicle speed and throttle opening shown in FIG. 5, and the shift is controlled.

Further, in the hydraulic pressure control circuit, the discharge pressure of the oil pump O/P driven by the engine 2 is regulated as a line pressure by the brake regulator valve 20, and the line pressure is applied to each of the friction elements as a working hydraulic pressure. It is now available as a.

As shown in FIG. 4, the pressure regulator valve 20 acts as a force in which the discharge pressure of the oil pump O/P acting on the pressure receiving surface 20d acts in the downward direction in the figure. The modifier pressure acting on the lower end of the plug 20c through the biasing force of the spring 20a and the circuit 76 moves upward in the figure. Each acts as an acting force, and the Subur 20b is placed at a position where these forces are balanced.
is moved, and the line pressure at port 20e is regulated.

Further, the modifier pressure is created by a pressure modifier valve 22, which is controlled by a signal pressure supplied from a line pressure solenoid 24.

The line pressure solenoid 24 is composed of an on-drain type solenoid valve.
4 is decoat-controlled, the pilot valve 2
The pilot pressure output from 6 is pressure-controlled, and this control pressure is supplied to the blur/mesher modifier valve 22 as a signal pressure.

Therefore, by controlling the signal pressure with the line pressure solenoid 24, the modifier pressure can be changed, and in turn, the line pressure can be controlled by the pressure regulator valve 20.

By the way, the line pressure solenoid 24 is driven by a control signal output from a line pressure control means 206 built into the control unit 10 shown in FIG.
Normally, the line pressure control means 206 outputs a signal corresponding to the throttle opening.

Here, in this embodiment, the control unit 10 includes:
Precharge pressure regulating means 210 and capacity N regulating pressure regulating means 2
12, and both means 2lO. 212, line pressure control is performed when the neutral (N) range is selected from the drive (D) range.

That is, the precharge pressure regulating means 210 inputs the range switching signal selected by operating the select lever 214, detects a signal selected from the N range to the D range, and sends a signal to the line pressure control means 206. output,
The line pressure regulated by the pressure regulator valve 20 is controlled so as to temporarily increase rapidly and then rapidly decrease.

That is, the line pressure regulated via the precharge pressure regulating means 210 changes from the N range to the D range as shown in FIG.
At the same time as switching to the range, constant shelf pressure (PCIPR
After this shelf pressure (PCIIPRS) continues for a certain period of time (PCHTIME), the predetermined pressure (CA
PPRS), and the shelf pressure (PCHPRS)
is precharged to the friction element that is engaged when switching from N to D range, that is, the low clutch R/C.

On the other hand, the capacity adjusting pressure regulating means 212 receives a precharge pressure end signal from the precharging pressure regulating means 210 and outputs a signal to the line pressure controlling means 206,
The line pressure is controlled to be gradually increased by the pressure regulator valve 20.

That is, as shown in FIG.
), the line pressure is gradually increased at a constant ramp rate (CAI'DPL) until the engagement completion time (SELTIME) until the low clutch R/C is completely engaged.

Note that after the engagement completion time (SELTIMB) has elapsed, the interrupt signal output to the line pressure control means 206 is stopped, so the line pressure is reduced to the normal line pressure.

With the above configuration, the functions of this embodiment will be explained along the flowchart of FIG. 7.

The above flowchart shows the precharge pressure regulating means 21.
0 and the capacity adjustment pressure adjustment stage 212, which is executed at predetermined short intervals.

That is, in the above flowchart, it is first determined in step I whether the current range position is the N range, and r-YE
In the case of SJ, proceed to step H to set the normal line pressure, then proceed to step ■ to set the precharge pressure regulating means 2.
PC}ITIIIE to the first timer set in 10
, and then proceed to step (3) to set the second timer provided in the capacity adjustment pressure regulating means 212 to set SELTIklE.
and then set the flag FALS by step ■
Set to E.

Note that the first and second timers are subtracted (-1) at regular intervals.
) and shall be stopped when it reaches zero.

On the other hand, if rNOJ is determined in step I above, N
Assuming that the range has been switched from the range to the D range, proceed to step ■, and check whether the second timer set in step ■ above has reached zero, that is, SELTIIII.
It is determined whether or not the period of Set.

Line pressure transient control when rNOJ is determined in the above step (■) first involves checking in step (2) whether or not the first timer set in the above step (■) has reached zero.
It is determined whether the PCITIME period has elapsed and the message “NO
'', proceed to step (3) and control the line pressure to the precharge pressure shelf pressure (PCIIPRS).

On the other hand, if rYEsJ is determined in the above step (2), the process proceeds to step After setting the lowest pressure, step mowing sets the flag to TRUE.

Further, if rYESJ is determined in the step

Therefore, in the hydraulic pressure control means of the automatic transmission of this embodiment, when the N range is selected from the D range and line pressure is supplied to the low clutch R/C, the pressure shown in FIG. First, high hydraulic pressure is introduced into the low clutch R/C by the precharge pressure, so the low clutch R/C
The precharge portion necessary for preparation for fastening C is quickly filled.

After the low clutch R/C is precharged in this way, the low clutch R/C is completely engaged by the capacity adjustment pressure that gradually increases the hydraulic pressure. C-fastening is performed smoothly.

In addition, by using the precharge pressure for transient control during selection in this way, quick precharging is performed, and the capacity adjustment pressure for actually engaging the low clutch R/C is gradually increased. After being precharged, the time until the low clutch R/C is engaged by the capacity adjustment pressure can be further shortened.

Therefore, in this embodiment, the selection time of the N-D range can be significantly shortened to enable smooth selection, and the engagement shock of the low clutch R/C and the generation of selection shock can be significantly reduced.

The engaged state of the low clutch R/C is maintained by the normal line pressure after the transient control at the time of selection is completed.

Effects of the Invention As explained above, in the hydraulic pressure control device for an automatic transmission of the present invention, the hydraulic pressure supplied to the friction element is temporarily increased rapidly when switching from the neutral range to the travel range. Then, there is a precharge pressure regulating means that rapidly lowers the pressure to create a shelf pressure for precharging, and a capacity adjustment means that gradually increases the working fluid pressure from the point at which the precharge pressure falls to create a capacity adjustment pressure for the friction element. Since the pressure regulating means is provided, when switching from the neutral range to the travel range, the precharging pressure regulating means quickly precharges the friction element and quickly prepares the friction element for engagement. Thereafter, the hydraulic pressure for actually engaging the friction element is gradually increased by the capacity adjustment pressure regulating means, so that the engagement of the friction element after precharging is performed in a short time, and the friction element is The shock when fully fastened can be significantly reduced.

Therefore, the selection from the neutral range to the driving range can be performed quickly, preventing the friction elements from seizing up, and greatly reducing the selection shock, thereby significantly improving vehicle ride comfort. It has various excellent effects.

[Brief Description of the Drawings] Fig. 1 is a schematic diagram showing the concept of the present invention, Fig. 2 is a schematic diagram showing an embodiment of the invention, and Fig. 3 is an automatic transmission to which the present invention is applied. A schematic configuration diagram showing the powertrain of
FIG. 4 is a schematic structural diagram showing a hydraulic pressure control circuit of an automatic transmission to which the present invention is applied, FIG. 5 is an explanatory diagram showing an example of a shift schedule used in the present invention, and FIG. Characteristic diagram of hydraulic pressure during select transition period controlled by the invention, seventh
The figure is a flowchart showing an example of processing for executing control performed in the present invention. l... Automatic transmission, 2... Engine, 3... Torqueco:/bar-9, 10... Huntroll unit, 2
0... Pressure regulator valve, 24... Line pressure solenoid, 206... Line pressure control means, 21
0...Precharge pressure regulating means, 212...Capacity regulating pressure regulating means, R/C...Low clutch (friction element)
. Figure 2 Figure 6 Figure 7

Claims (1)

[Claims] (1) An automatic transmission comprising a plurality of hydraulically operated friction elements that switch transmission gears by a combination of engagement and disengagement, and a hydraulic pressure supply circuit that supplies operating hydraulic pressure to the friction elements, a precharge pressure regulating means for creating a shelf pressure for precharging by temporarily raising the working fluid pressure rapidly and then rapidly lowering it to create a shelf pressure for precharging when a range signal is input to switch from the neutral range to the driving range; A hydraulic pressure control device for an automatic transmission, comprising: capacity adjustment pressure regulating means for gradually increasing the working hydraulic pressure from the point at which the precharge pressure falls to create a capacity regulation pressure for the friction element. .