JPH02261962A - Shifting liquid pressure control device for automatic transmission - Google Patents

Abstract

PURPOSE:To shorten shift lag by furnishing a throttle amount changeover means, and thereby quickening the timing at which the throttle amount of a variable throttle means is switching to Small when a specified value is exceeded by the change rate of the degree of accel. opening at the time of down-shift. CONSTITUTION:An accel. pedal is stamped quickly at the time of stamping down-shift of an automatic transmission to be sensed by a sensing means (f), and the change rate of the degree of accel. opening at a power source (c) sensed by a sensing means (g) is enlarged, so that a throttle amount changeover means (h) therein sets smaller the throttle amount of a variable throttle means (e) in early stage. This raises the liquid pressure supplied to a friction element (a) to cause early engagement, and rotation-up of the power source (c) is promoted by rotation input on the drive wheel side, which permits quick rising to a revolving speed corresponding to the gear ratio after down-shift. Thus the period of shifting is shortened to lead to decrease shift lag, which should suppress generation of shift shocks.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a shift hydraulic pressure control device for an automatic transmission, and more particularly to a shift hydraulic pressure control device that is supplied to a friction element that is newly engaged during a downshift.

Conventional technology In general, automatic transmissions installed in vehicles are equipped with a plurality of planetary gear sets as transmission gears, and the viscous relationship of each component of these planetary gear sets is determined by the friction of multiple clutches, brakes, etc. Various gears can be obtained by switching by engaging or disengaging the elements.

By the way, the line pressure controlled by a hydraulic pressure control circuit is used as the hydraulic pressure for engaging the friction element, and the line pressure is changed depending on the engine load (throttle opening), and when the engine load is large, Sometimes the line pressure is increased to prevent slipping of the friction elements.

Therefore, when the automatic transmission is shifted, the line pressure is regulated according to the engine load, and is removed from the friction element that was engaged before the shift, and is about to be engaged after the shift. It is supplied to the friction element to perform switching of the friction element.

For this reason, high line pressure is supplied to the friction element that is about to be newly engaged when the pedal is downshifted, and if such high line pressure is supplied at -. Shock will occur and cause shift shock.

Therefore, in conventional automatic transmissions, for example,
As disclosed in Japanese Patent No. 83539, by providing an orifice in the hydraulic pressure supply circuit of the low clutch as a friction element and increasing the amount of restriction, the hydraulic pressure is supplied slowly during gear shifting, and the above-mentioned engagement shock is alleviated. It is now possible to do so.

However, if hydraulic pressure is constantly supplied or removed through the orifice, the engagement time of the friction element becomes longer than necessary, and when the accelerator pedal is depressed to downshift, the driving wheel Since the rotational input from the side is cut off for a long time, the engine speed increases slowly, causing a shift lag.

Therefore, in the above-mentioned conventional automatic transmission, a timing valve is provided that bypasses the orifice and connects the hydraulic pressure supply circuit, that is, reduces the amount of throttle. The friction elements are fastened together.

Problems to be Solved by the Invention However, in such conventional transmission hydraulic pressure control devices, the operating point of the timing valve is determined by the vehicle speed.
At high vehicle speeds, reduce the aperture amount (or increase the timing).
It was designed to slow down at low vehicle speeds.

Therefore, during a downshift in the direction shown in the shift diagram in Figure 11, that is, during a normal downshift that does not involve pressing down on the accelerator pedal to a certain extent, it is possible to perform an appropriate shift with less shift shock at low vehicle speeds. However, at the same low vehicle speed, when downshifting in direction B in the figure, in other words, when pressing the pedal down, the engagement timing of the friction element becomes delayed, and a rapid increase in engine rotation cannot be expected, so it is difficult to shift gears. There was an issue where the lag felt large.

In view of such conventional problems, the present invention provides an automatic transmission that can reduce the shift shock during normal downshifts, while promoting an increase in engine speed during downshifts and shortening shift lag. The present invention aims to provide a variable speed hydraulic pressure control device.

Means for Solving the Problems To achieve these objects, the present invention, as shown in FIG. 1, comprises a plurality of hydraulically actuated friction elements a.

In an automatic transmission that switches gears by engaging or disengaging these friction elements a and b, and outputs manual rotation from a power source C by appropriately changing the speed, the friction element a is engaged during downshifting. Variable throttling means e, which is provided in the hydraulic pressure supply circuit d, for switching the amount of throttling, downshift detection means r, that detects a downshift, and accelerator change rate detection means g, that detects the rate of change in accelerator opening. and an aperture wedge means for advancing the timing of switching the aperture amount of the variable aperture means e to a small value when the rate of change in the accelerator opening is equal to or higher than a predetermined value during downshifting.

Further, it is preferable that the limit value of the accelerator change rate for switching the variable aperture means e be mapped and manually inputted in advance to the aperture main switching means, and the aperture main switching means be controlled in accordance with the map. .

Effect With the above-described configuration, the shift hydraulic pressure control device for an automatic transmission of the present invention has the advantage that the accelerator opening detected by the accelerator change rate detecting means g is The rate of change becomes large, and in this case, the variable aperture means e is changed via the aperture amount switching means.
The aperture amount is set to a small value early.

Therefore, the hydraulic pressure supplied to the friction element a becomes high, and the friction element a is engaged at an early stage, and the rotational input of the driving wheel side promotes the increase in rotation of the power source C.
The rotation of the power source C quickly reaches the rotation number corresponding to the gear ratio after downshifting, thereby shortening the shift period and, by extension, reducing the shift lag.

If the rate of change is small, the switching point of the variable throttle means e should be set later than the original timing, that is, the downshift time when the pedal is pressed down (by doing so,
Control that focuses on reducing shift shock becomes possible.

Further, by performing switching of the variable aperture means e described in 1-in accordance with the map input to the aperture amount switching means, quick control becomes possible, and the circuit configuration of the aperture amount switching means is simplified.

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 shift hydraulic pressure control device for an automatic transmission showing an embodiment of the present invention, in which reference numeral 100 denotes a control unit te, and a control signal outputted from the control unit 100 is used to control the automatic transmission. hydraulic pressure control of the engine.

The automatic transmission A/T is configured with a power train shown in FIG. 3, for example, and has a lock-up clutch LU/C.
The rotation of the engine E is coupled to the engine E as a power source through the torque converter T/C and the automatic transmission A/T. Output.

By the way, the transmission gear train of the automatic transmission A/T is a front planetary gear set G consisting of front sun gear Sl, front pinion gear Pl, front internal gear R1, and front planet carrier PSI, and rear sun gear S, rear pinion gear Pffi, and rear internal gear PSI. A rear planetary gear set G consisting of a Lugia R1, a rear planet carrier PC, and a rear planetary gear set G consisting of these two sets.
, , G are arranged in tandem.

In addition, as shown in the figure, the power train including the above-mentioned transmission gear train includes a reverse clutch R/C, a high clutch +1
/C, low clutch L/C, low & reverse brake L
Friction elements such as &R/B and bunt brake B/B are incorporated, and in addition to these friction elements, a one-way clutch OWC is incorporated.

By the way, in a power train having such a configuration, various gears can be obtained by engaging and disengaging various friction elements by line pressure supplied from a hydraulic pressure control circuit described later, as shown in Table 1 below. It looks like this.

In addition, in the same table, the mark ○ represents the fastened state, and the no mark represents the released state.

Table 1 Note that the band brake B/B is actuated by a band servo 17, which will be described later, and includes an engagement chamber and a release chamber, and the band brake B/B is engaged by supplying hydraulic pressure to the engagement chamber. In this state, the bunt brake H/B is configured to be released by supplying hydraulic pressure to the release chamber.

FIG. 4 shows a hydraulic pressure control circuit for controlling the hydraulic pressure supplied to each of the friction elements, and the friction elements are engaged or released by the control hydraulic pressure supplied from the hydraulic pressure control circuit.

In the above hydraulic pressure control circuit, oil pump 0/P, pressure regulator valve 1. Manual valve 2. Throttle valve 3. Day tent & fail safe valve 4.
Kickdown modulator valve 5. Pressure modifier valve6. Cutback valve 7, backup valve 8. Pilot valve 9. 1-2 Shift valve 10, 2-3 Shift valve 11. 3-4 Shift valve 1
2゜1-2 solenoid valve 13.2-3 solenoid valve 14.3-4 solenoid valve 15. Aki 1 mullet
9 valves 16. Band servo 17. Servo release timing valve 18. Low clutch accumulator 19.
High clutch control valve 20. High clutch solenoid valve 21° low clutch timing valve 2
2. Rotor latch solenoid valve 23. 4-3 timing valve 24. 3-2 timing valve 25. Governor valve 26. Torque converter regicolator valve 27
, Locka Knob Valve 28. Lock-up solenoid pal 7'29. An I+/inverter reducing valve 30 is provided, and each of these valves is connected to -1- through the illustrated circuit.
, De are connected to each friction element and torque converter T/C.

In the above hydraulic control circuit, the 1-2 shift valve 10.2-3 shift valve 11.3-4 is shifted by turning on and off the 1-27 solenoid valves 13, 2-3 solenoid valves 14, and 3-4 solenoid valves 15. Valve 1
2 is switched in the vertical direction in the figure as shown in Table 2, thereby supplying and removing hydraulic pressure to the friction elements that are engaged and released at each gear stage shown in Table 1 above.

Table 2 Note that the detailed configuration and functions of each component of the hydraulic pressure control circuit are the same as those described in JP-A-62-83539, and detailed explanation thereof will be omitted.

By the way, the above 1-2 solenoid valve 13, 2-3 solenoid valve 14 and 3-4 solenoid valve 15
The ON and OFF signals output to the engine are controlled according to a shift schedule determined by the vehicle speed and accelerator opening as shown in FIG. 5, for example.

By the way, in the power train of this embodiment, the fourth
When downshifting from speed to third speed in a high-speed state, the band brake B/H is released and the low clutch L/C is engaged as shown in Table 1 above. As shown in FIG. 1, a one-way orifice 52 is provided in the hydraulic pressure supply circuit 50 of the low clutches I and /C, and high line pressure is slowly supplied to start engagement of the low clutches L/C. Further, the hydraulic pressure supply circuit 50 is provided with a low clutch timing valve 22 in the bypass passage 54 to bypass the one-way orifice 52, and the low clutch timing valve 22 is provided in the bypass passage 54 to bypass the one-way orifice 52. The hydraulic pressure supply circuit 50 is connected to the one-way orifice 5
It is possible to communicate without going through 2.

That is, the low clutch timing valve 22 is ON.
, rotor latch solenoid valve 23 that is driven OFF.
By supplying the pilot pressure supplied from the circuit 56 to the low clutch timing valve 22 through the
The low clutch timing valve 22 is switched upward in the figure to communicate with the bypass passage 54, and in this state, the one-way orifice 52 does not exert its throttling function and is in communication, that is, an extremely small It can be considered that the aperture is set to the aperture amount.

On the other hand, by draining the pilot pressure by the low clutch solenoid valve 23, the low clutch timing valve 22 is switched downward in the figure to block the bypass passage 54, and the function of the one-way orifice 52 is exerted to throttle it. 11'' LI is set large.

In this embodiment, the low clutch solenoid valve 2
3 drains the pilot pressure by the OFF signal and turns it ON.
The signal is activated to supply pilot pressure to the low clutch timing valve 22.

In this way, the variable throttle means 58 is constituted by the one-way orifice 52 degree low clutch timing valve 22 and the low clutch solenoid valve 23, which can make the throttle of the hydraulic pressure supply circuit 50 variable.

Here, in this embodiment, the control unit 100
Inside, a throttle sensor 102 and a vehicle speed sensor 104 are installed.
A shift determination means 106 as a downshift detection means, which manually determines a shift according to the shift schedule as shown in FIG. Shifting that outputs ON and OFF signals to the 1-2 solenoid valve 13, 2-3 solenoid valve 14, and 3-4 solenoid valve 15 shown in Table 2 above based on the shift determination signal from the shift determination means 106. Control means 108 are provided.

The control unit 100 also includes an accelerator change rate detecting means that manually inputs a throttle opening signal from the throttle sensor 102 and calculates a rate of change in the accelerator opening corresponding to the throttle opening. The throttle opening change rate calculation means 110 is provided with an opening change rate (1″
+1) Signal, the throttle (TO) Q from the throttle sensor 102 and the downshift signal detected by the shift determination means 106 are input, and the variable throttle means 5
An aperture amount determining means 112 is provided for determining the size of the aperture amount.

The size of the throttle amount determined by the throttle amount determining means +12 is output to the variable throttle control means 114, and a drive signal is output from the variable throttle control means 114 to the low clutch solenoid valve 23. These aperture m determining means 112 and variable aperture control means 114 constitute an aperture amount switching means 116.

Note that when the aperture amount determination means 112 determines the aperture amount of the variable aperture means 58, a map as shown in FIG. .

That is, in the map, the vehicle speed is plotted in the horizontal direction, and the throttle opening degree T11 is plotted in the vertical direction, and the limit values of the rate of change at the corresponding points of both are shown, and are detected by the throttle opening rate of change calculating means 110. When the value exceeds the limit value, the timing at which the aperture amount of the variable aperture control means 114 is set to a small value is advanced.

FIG. 8 shows the flow of the control performed by the throttle unit 100, and this flow will be explained step by step below. Before the control according to this flow is executed, the aperture amount of the variable aperture means 58 is (The set state is set, that is, the ON signal is output to the low clutch solenoid valve 23 and the low clutch timing valve 22 is set to shut off the bypass passage 54.

That is, in the above flowchart, the throttle opening degree Ti11 is read in step l, and the throttle opening degree Ti11 is read in step n.
So T11. After reading Δt, a preset sampling time Δt is counted, and after this Δ, the throttle opening degree T11. Load in step ■.

Then, in step ■, the vehicle speed ■ is read, and from these throttle opening degrees TH,, the optimum shift position is read from the shift schedule (shift point map) shown in Figure 5 from the vehicle speed, and in the next step ■, it is determined whether the downshift will be performed. is determined, and if r N Oj, the process returns to step I, and if rYEsj, the process proceeds to step 2 where the throttle opening irn read in step 1 and step m is determined.

and TI(,), the rate of change T'H of the throttle opening is determined.

Therefore, it is given.

In the next step (2), based on the map shown in FIG. 7, a predetermined value at which the rate of change of the throttle opening is the limit is read from the throttle opening Ttl and the vehicle speed (2), and in step IX, the rate of change -I is determined from the predetermined value. '11 is large or not, and if rYEsJ, proceed to Step 2BX and apply an ON signal to the rotor latch solenoid valve 23 for a predetermined period of time (until low clutch 1./C is completely engaged). time), and set the aperture amount of the variable aperture means 58 to a small value, while in the case of l' N OJ, proceed to step ℃,
An OFF signal is output to the low crawler/notch solenoid valve 23, and the throttle amount of the variable throttle means 58 is continuously set to a large value.

With the above configuration, in the shift hydraulic pressure control device of this embodiment, when downshifting from 4th gear to 3rd gear, after the band brake B/B is released, the low clutch I, /C is engaged, but the low clutch 1. The variable throttle means 58 provided in the hydraulic pressure supply circuit 50 of /C determines the point in time at which the throttle amount is switched from large to small based on the throttle opening change rate calculated by the throttle opening change rate calculation means 11O. It is now judged based on

For this reason, when the driver attempts to accelerate, the shift hydraulic pressure supplied to the low clutches L and /C is determined to be the throttle main vehicle, as shown in Figure 9, from the solid line indicating the large throttle amount. The hydraulic characteristics are changed as shown by the broken line, and the hydraulic pressure rises at a high rate (by this, the timing of engagement of the low crawler/notch L/C can be brought forward.

On the other hand, in the middle of a downshift, the engine rotation is lower than the rotation of the drive wheel.

When the low clutch L/C is engaged in this state, rotational force is applied to the engine from the driving wheels due to the engine braking action, and the rotational speed of the engine is increased.

Therefore, by advancing the engagement timing of the low clutch L/C during the above-mentioned downshift, the manual rotation of the driving wheel promotes the engine's r = IJ rotation, and the solid line in Fig. 1O (a) As shown, the start of the engine rotation becomes thicker ((the broken line in the figure is the conventional characteristic),
Accordingly, since the time required to reach the target engine speed during downshifting is shortened, the shift lag can be significantly shortened and acceleration performance can be reasonably improved.

By the way, when the downshift is not due to the above-described depression but is a normal downshift, the rate of change in the throttle opening is less than a predetermined value, so the variable throttle means 5
Because the timing to set the aperture amount to small in 8 is delayed,
As shown in FIG. 1O(b), the rate of increase in engine speed also decreases, but the output torque T. can be obtained as a characteristic with few sudden fluctuation components, and it is possible to significantly reduce shift shock.

Although this embodiment has been shown as an example of downshifting from 4th speed to 3rd speed, in the hydraulic pressure supply circuit disclosed in this embodiment, downshifting from 3rd speed to 2nd speed is performed. In this case, the release pressure is removed from the band servo 17 when the band brake B/H is engaged, but the present invention can also be applied when the release pressure is removed.

In addition, in this embodiment, the preset map shown in FIG. 7 is used in the aperture r1 determining means 112 to determine whether the rate of change in throttle opening is greater than or equal to a predetermined value. By simplifying the judgment, it is possible to respond more quickly to the control and simplify the electric circuit.

Advantages of the Invention As described in 2, in the shift hydraulic pressure control device for an automatic transmission of the present invention, in claim 1, the rate of change in the accelerator opening is detected, and the rate of change is set to a predetermined value at the time of downshifting. (When it becomes thicker, the throttle of the variable throttle means installed in the hydraulic pressure supply circuit of the friction element is set to a smaller value. The rate of change becomes large (and becomes equal to or higher than a predetermined value), and the amount of throttle of the variable throttle means is set to be small at an early stage, and the timing of engagement of the friction element becomes early.

Therefore, the rotation of the power source is accelerated by the rotation input from the driving wheels, and the rotation of the power source quickly reaches the rotation speed corresponding to the gear ratio after downshifting, and when accelerating. A significant reduction in shift lag can be achieved.

On the other hand, if the rate of change is small, the switching point of the variable throttle means should be set later than the original timing, that is, the downshift time when the pedal is pressed down (thereby, emphasis should be placed on reducing shift shock). It becomes possible to control the position.

Further, in claim 2, by performing switching of the variable throttle means according to a map manually input to the throttle air switching means, rapid control is possible, and the circuit configuration of the throttle air switching means is improved. This provides various excellent effects such as simplified Lli.

[Brief explanation of 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 present invention, and FIG. 3 is a schematic diagram showing the power train of an automatic transmission to which the present invention is applied. figure,
FIG. 4 is a schematic configuration diagram showing a hydraulic pressure control circuit of an automatic transmission to which the present invention is applied, and FIG. 5 is an explanatory diagram showing an example of a shift schedule used in the present invention. FIG. 7 is a control map used in an embodiment of the present invention; FIG. 8 is a flowchart showing an example of a process for executing control according to the present invention; FIG.
The figure is a characteristic diagram of the shift hydraulic pressure achieved by the present invention, and Fig. 10 (
a) and (b) are characteristic diagrams of the engine and output torque when the control modes of the present invention are different, and FIG. 11 is an explanatory diagram showing the state of downshift using a shift diagram. 22...Low clutch timing pulp, 23...
Low clutch solenoid valve, 50... Hydraulic pressure supply circuit, 52... One-way orifice, 54... Bypass passage, 58... Variable throttle means, 100... Control unit, 102-... Throttle sensor ,+04
. . . Vehicle speed sensor, 106 . . . Shift determination means (downshift detection means), 108 . . . Shift control means, 110
...Throttle opening change rate calculation means (accelerator change rate detection means), 112... Throttle amount determination means, 114...
- Variable diaphragm control means, 116... diaphragm switching means, L
/C...Low clutch (friction element), A/T...Automatic transmission, E...Engine (power g). Figure 3 Figure 5 Vehicle speed Junmo Figure 6 T) ( Figure 9 eC

Claims (2)

[Claims] (1) In an automatic transmission that is equipped with a plurality of hydraulically actuated friction elements, engages or releases these friction elements to switch gears, and outputs the input rotation from the power source by appropriately changing the gear. A variable throttling means is installed in the hydraulic pressure supply circuit of the friction element that is engaged when the engine is engaged, and changes the amount of throttling from small to large, a downshift detection means detects a downshift, and an accelerator change rate detects the rate of change in the accelerator opening. An automatic control system comprising: a detection means; and an aperture amount switching means for advancing the timing of switching the aperture amount of the variable aperture means to a small value when the rate of change in the accelerator opening is equal to or greater than a predetermined value during a downshift. Transmission hydraulic pressure control device. (2) A limit value of the accelerator change rate for switching the variable aperture means is input into the aperture amount switching means as a map in advance, and the aperture amount switching means is controlled in accordance with the map. Item 1. A shift hydraulic pressure control device for an automatic transmission according to item 1.