JPH08334169A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE: To carry out smooth and speedy gear lever thrusting control by judging it as invalid stroke filling completion at the time when an absolute value of a rate of rotational change of a coupling means output shaft is higher than a specified rate of change and a difference between rotating speed of an engine and rotating speed of the coupling means output shaft is hither than a specified value. CONSTITUTION: Number of rotation of an engine Ne, Number of rotation of a turbine of a torque converter Nt and a rate of change of turbine rotation dNt/dt are detected, and a difference ΔN of the number of rotation of the engine Ne and the number of rotation of the turbine Nt is computed. When it is judged that this difference ΔN becomes larger than a first allowance ΔN1 and an absolute value of the rate of change of turbine rotation dNt/dt becomes larger than a first allowable rate RNt(1), it is judged that invalid stroke filling of a third clutch CL3 is completed. Thereafter, it is transferred to control to actuate a solenoid valve in accordance with a first duty ratio as the solenoid valve is left at an intermediate duty ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission (including a continuously variable transmission for automatic shifting) used for vehicles and the like,
More specifically, the present invention relates to a shift control device that performs shift control when switching from a neutral range to a travel range. The switching control from the neutral range to the traveling range (forward range or reverse range) is referred to as in-gear control.

[0002]

2. Description of the Related Art An automatic transmission has a plurality of gear trains, and a plurality of power transmission paths constituted by the gear trains are engaged with friction engagement elements such as clutches and brakes by hydraulic pressure or the like. To select and shift gears. Here, when gear shifting is performed, the power transmission path is switched and the gear ratio changes, so there is a problem that a sudden shift will cause gear shift shock. For this reason, various measures have heretofore been made to adjust the engagement of the friction engagement elements so as to perform a smooth gear shift without a shock.

In such a shift shock, in a state where the shift lever is positioned at the neutral position and the neutral range is set, the shift lever is switched to the forward (reverse) range position to move forward (or reverse).
The shift shock that occurs when setting the range (that is, in the case of in-gear) is particularly likely to cause a problem. this is,
The in-gear control is a control that shifts from the neutral range, which is an unloaded state, to the forward range (or reverse range), but the input torque at this time is small, and the transmission torque fluctuation ratio with respect to the change in the engagement capacity of the friction engagement element This is because the engagement control of the frictional engagement element requires extremely delicate control.

Therefore, various proposals regarding in-gear control have been made in the past, and as an example, Japanese Patent Laid-Open Publication No. 6-58242 (1994) is used.
There is a control device disclosed in Japanese Patent Publication No. 109130. In this device, when a command to switch from the neutral range to the running range is generated, first the first switching stage is executed to increase the solenoid valve duty ratio to perform the first quick fill, and then the second switching stage. To reduce the clutch supply pressure at a predetermined duty ratio reduction rate, and to perform a third switching stage that minimizes the supply pressure at a duty ratio determined based on the engine speed immediately before complete engagement. It has become.

With such control, the first quick fill fills the oil chamber of the piston in the friction engagement element with hydraulic oil and puts the friction engagement element into a state immediately before engagement (the piston is moved to a position immediately before engagement). (Moving) invalid stroke reduction is performed, and if this first quick fill is appropriately performed, smooth in-gear control can be performed. However, if the first quick fill is completed and the process moves to the next control stage before the invalid stroke filling is completed, the remaining invalid stroke filling time may become longer and an in-gear delay may occur. However, if the fast quick fill is continued, the engagement of the frictional engagement element may be suddenly increased and an in-gear shock may occur.

From the above, Japanese Patent Laid-Open No. 63-280
Japanese Patent Laid-Open No. 929 discloses a device that determines that the filling is completed when the rotation change rate of the input shaft of the transmission (the turbine shaft of the torque converter) becomes equal to or greater than a predetermined value.

[0007]

However, the engine rotation and the turbine rotation of the torque converter are not always constant rotations during in-gear, but they often change. Therefore, such changes cause rotation of the turbine shaft. The rate of change may exceed a predetermined value. For this reason, there is a possibility that an erroneous determination may occur if the determination of filling completion (or completion of invalid stroke filling) is made based only on the rate of rotation change of the turbine shaft (transmission input shaft) as described above. If the in-gear control is performed under such an erroneous judgment, in-gear delay or in-gear shock may occur.

The automatic transmission is not limited to the one having the gear train as described above, but may be an automatic transmission having a continuously variable transmission mechanism. Even in an automatic transmission having such a continuously variable transmission mechanism, the forward range,
It is possible to switch between neutral range and reverse range, and there is the same problem of in-gear control as above.

The present invention has been made in view of these problems.
An object of the present invention is to provide a shift control device for an automatic transmission, which can accurately detect the completion of invalid stroke reduction during in-gear control and can achieve smooth and quick in-gear control.

[0010]

In order to achieve such an object, the shift control device of the present invention comprises a coupling means connected to the output shaft of the engine, a transmission mechanism connected to the output shaft of the coupling means, and The speed change mechanism includes a friction engagement element capable of setting at least a traveling range and a neutral range, and engagement control means for controlling engagement operation of the friction engagement element. The engagement actuation control is performed by controlling the engagement actuation hydraulic pressure of the engagement element according to the hydraulic pressure command signal. Here, when the neutral range is switched to the travel range, the engagement control means starts the invalid stroke closing control for setting the engagement operating oil pressure of the friction engagement element for setting the travel range to a predetermined high pressure. When the absolute value of the rotational change rate of the coupling means output shaft is equal to or higher than a predetermined change rate and the difference between the engine rotation speed and the rotational speed of the coupling means output shaft is equal to or more than a predetermined value after the invalid stroke closing control is started. It is judged that the invalid stroke closing is completed, the invalid stroke closing control is ended, and
The engagement hydraulic pressure is set to a hydraulic pressure lower than a predetermined high pressure.

A torque converter is often used as the coupling means. In this case, the absolute value of the rotational change rate of the turbine shaft of the torque converter is equal to or higher than a predetermined change rate, and the engine speed and the turbine shaft are changed. When the difference from the rotation speed is equal to or more than a predetermined value, it is determined that the invalid stroke closing is completed, and the control for ending the invalid stroke closing control is performed.

When the neutral range is switched to the traveling range, the load on the coupling output shaft (or turbine shaft) increases in accordance with the engagement of the frictional engagement element, so that the coupling output shaft is generally used. (Turbine shaft) rotation decreases and the difference between engine rotation and coupling output shaft (turbine shaft) rotation (slip rotation speed of torque converter)
Can be said to increase. However, the engine rotation is not always constant during the in-gear control.For example, the in-gear control may be performed while depressing the accelerator pedal or returning the accelerator pedal with the foot released from the accelerator pedal. In such a case, the change in the rotation of the coupling output shaft (turbine shaft) varies depending on each state.

For this reason, it is difficult to judge the completion of the invalid stroke filling only by the rotational change rate of the coupling output shaft (turbine shaft). However, in any of the above states, when the frictional engagement element starts engaging and the coupling output shaft (turbine shaft) load starts to increase, the difference in rotation (slip amount of the torque converter) increases. The present invention has been made in view of the above circumstances. In the present invention, in addition to the rate of change of the coupling output shaft (turbine shaft) rotation, the difference between the engine rotational speed and the coupling output shaft (turbine shaft) rotational speed. ,
That is, the completion determination of the invalid stroke closing is made based on the slip amount of the torque converter. For this reason, it is possible to accurately determine whether or not the invalid stroke closing has been completed regardless of which state the accelerator pedal is in.

When the engine rotation fluctuates relatively finely, the shaft rotation fluctuation via the coupling (torque converter) causes a time delay with respect to the engine rotation fluctuation. Therefore, the engine rotation fluctuation and the coupling output shaft ( Turbine shaft) Rotational fluctuations are out of phase and the engine rotational fluctuation peaks and coupling output shaft (turbine shaft) rotational fluctuations valleys are at the same time, and the difference between the engine rotational speed and the coupling output shaft (turbine shaft) rotational speed Can be large. Therefore, there is a possibility that the invalid stroke closing completion determination may be inaccurate based on only the difference between the engine rotational speed and the coupling output shaft (turbine shaft) rotational speed. However, in the present invention, the coupling output shaft (turbine shaft) rotation change rate is also used as a criterion, so that an accurate determination can be made even in such a case.

As the transmission mechanism, a transmission mechanism composed of a plurality of power transmission paths having different gear ratios such as a gear type automatic transmission or a continuously variable transmission mechanism (for example, a metal V-belt continuously variable transmission mechanism) is used. There are things such as configured. In the case of a gear type automatic transmission, a torque converter is generally used as the coupling means, and has a plurality of friction engagement elements for selectively setting a predetermined power transmission path from the plurality of power transmission paths. Further, in the case of a continuously variable transmission mechanism, a mechanical coupling means, a fluid coupling, a torque converter, etc. are used as the coupling means, and a start control friction engagement element capable of setting at least a traveling range and a neutral range. Have.

It should be noted that the high-pressure hydraulic pressure command signal for reducing the ineffective stroke is continuously output for a predetermined period of time after the neutral range is switched to the running range, and then the rotation change of the turbine shaft is performed. The intermediate hydraulic pressure command signal is preferably output until the absolute value of the rate becomes equal to or higher than a predetermined change rate and the difference between the engine rotation speed and the turbine shaft rotation speed becomes a predetermined value or more. With this configuration, the intermediate hydraulic pressure is set when the invalid stroke closing is completed, and the next control can be smoothly performed even if the transition to the next control stage is slightly shifted from the completion of the invalid stroke closing.

When the squat-in gear control is performed in which the starting gear is set via the high-speed gear when the neutral range is switched to the running range, the engagement control of the high-speed gear is performed. The absolute value of the rotational change rate of the turbine shaft becomes equal to or greater than a predetermined change rate from the time when the invalid stroke reduction control is switched from the neutral range to the running range, and the difference between the engine rotation speed and the turbine shaft rotation speed is the predetermined value. It is desirable that the control stage is configured to output the maximum hydraulic pressure command signal until the above.

When such squat control is performed, not only the engagement control of the high speed side gear stage but also the invalid stroke filling control in the starting gear stage is necessary. You may judge with. In this case, the determination value of the absolute value of the rotational change rate of the turbine shaft and the determination value of the difference between the engine rotation speed and the turbine shaft rotation speed for determining the invalid stroke reduction of the high-speed gear are It is possible to use a value different from the determination value for determining the invalid stroke reduction of the gear shift stage.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of the structure of a power transmission system of an automatic transmission in which shift control is performed by the shift control device according to the present invention. This transmission has an engine output shaft 1
And a transmission input shaft 3 connected to the turbine shaft of the torque converter 2, and a planetary transmission mechanism is arranged on the input shaft 3.

This speed change mechanism has first, second and third planetary gear trains G1, G2 and G3 arranged in parallel on the transmission input shaft 3. Each of the gear trains is located at the center of the first to third sun gears S1, S2 and S3, and the first to third planetary pinion P1 that revolves around the first to third sun gears while meshing with the first to third sun gears. , P
2, P3 and the first to third carriers C1 and C that rotatably hold the pinion and rotate in the same manner as the revolution of the pinion.
2, C3, and first with internal teeth that mesh with the pinion
-It comprises 3rd ring gear R1, R2, R3.
The first and second planetary gear trains G1 and G2 are double pinion type planetary gear trains, and the first and second pinion P1 and P2 are respectively composed of two pinions P11, P12 and P21, P22 as shown. To be done.

The first sun gear S1 is always connected to the input shaft 3, and the first carrier C1 can be fixedly held by the first brake B1 and is always connected to the second sun gear S2. The first ring gear R1 is releasably connected to the first carrier C1 and the second sun gear S2 via a third clutch CL3. The second carrier C2 and the third carrier C3 are always connected and the output gear 4 is always connected. Second ring gear R2 and third ring gear R
3 is always connected, and these are the second brake B2.
It can be fixedly held by and is connected to the case via the one-way clutch B3 so as to generate a braking action only for the rotation in the forward drive direction. Further, these are connected via the second clutch CL2. It is detachably connected to the input shaft 3. The third sun gear S3 is detachably connected to the input shaft via the first clutch CL1. Further, an input rotation sensor 9a and an output rotation sensor 9b are arranged as shown.

In the transmission configured as described above, the engagement and disengagement control of the first to third clutches CL1 to CL3 and the first and second brakes B1 and B2 is performed to set the gear speed and control the gear shift. be able to. In particular,
If engagement / disengagement control is performed as shown in Table 1, the fifth forward speed (1S
T, 2ND, 3RD, 4TH, 5TH), 1st reverse (R
EV) can be set.

In Table 1, the second brake B2 at 1ST is shown in parentheses, but this means that the one-way clutch B3 does not need to be engaged with the second brake B2.
This is because the 1st shift speed can be set by the action of. That is, if the first clutch CL1 is engaged, the 1ST gear can be set without engaging the second brake B2. However, the one-way clutch B3 cannot tolerate power transmission opposite to that on the drive side, and therefore the second brake B2
1ST in the non-engaged state is a gear stage where the engine brake is not effective, and when the second brake B2 is engaged, the gear stage is where the engine brake is effective. Incidentally, 1st in the D range is a gear stage where the engine brake does not work.

[0024]

[Table 1]

Next, the first to third clutches CL1 to CL3
A control device for engaging and disengaging the first and second brakes B1 and B2 will be described with reference to FIGS. 2 to 4 show each part of the control device, and these three figures constitute one control device. Further, among the oil passages in each figure, the ones with a circled alphabet (A to Y) at the end means that they are connected to the oil passages with the same alphabet in other figures. Further, the cross mark in the figure means that the part is drained.

Hydraulic oil is supplied from the hydraulic pump 10 to this control device, and this hydraulic oil is adjusted to the line pressure P1 by the regulator valve 20 and sent to the oil passage 100 and supplied as shown in the figure. . In this control device, in addition to the regulator valve 20, a manual valve 25 connected to a shift lever in the driver's seat and operated by a driver's manual operation, and six solenoid valves SA to
SF and 6 hydraulically operated valves 30, 35, 40, 4
5, 50, 55 and four accumulators 71 to 74 are arranged. Solenoid valves SA, SC, SF
Is a normally open type valve and these valves are opened when the solenoid is deenergized. On the other hand, the solenoid valves SB, SD and SE are normally closed type valves and are closed when the solenoid is deenergized.

In the following, the valve 30 is a reducing valve, the valve 35 is an LH shift valve,
Valve 40 is FWD pressure switching valve, valve 45
Is called a REV pressure switching valve, the valve 50 is called a delivery valve, and the valve 55 is called a relief valve.

Each valve is operated according to the operation of the manual valve 25 and the operation of the solenoid valves SA to SF, and the shift control is performed. In this case, the relationship between the operation of each solenoid valve and the speed stage set according to this operation is shown in Table 2 below. O in this table 2
N and OFF represent ON and OFF of the solenoid.
Although the operation of the solenoid valve SF is not shown in Table 2, this solenoid valve SF is used for increasing the line pressure when setting the reverse speed stage, and is not used for setting the shift stage. Because there is.

[0029]

[Table 2]

The above control will be described below. First, consider a case where the D range (forward range) is set by the shift lever and the spool 26 of the manual valve 25 moves to the D position. In the figure, the spool 26
Is in the N position, the right end hook portion is moved to the D position to the right, and the spool 26 is positioned in the D position. At this time, the hydraulic oil having the line pressure P1 is the oil passage 1 branched from the oil passage 100.
01, 102, FWD switching valve 40
It is sent from the oil passage 103 to the manual valve 25 through the spool groove of. Then, it is sent to the oil passages 110 and 120 via the groove of the spool 26. The oil passage 110 is closed in the REV switching valve 45 in this state.

The hydraulic oil having the line pressure P1 sent to the oil passage 120 is branched into the oil passages 121, 122, 123, 124, 12.
5 through solenoid valves SF, SE, S respectively
It is supplied to D, SB and SA. Line pressure P of oil passage 120
1 also acts on the right end of the L-H shift valve 35 to move the spool 36 of this valve 35 to the left. The branch oil passage 126 of the oil passage 120 is connected to the right side of the delivery valve 50,
The oil passage 127 branched from the oil passage 126 is provided with the relief valve 5
5 is connected to the left end of the spool 55, 5 of this valve 55.
Move 7 to the right.

On the other hand, the branch oil passage 103a of the oil passage 103 is F
The spool 41 is connected to the right end of the WD switching valve 40 and is pressed leftward by the line pressure P1. Oil passage 10
The branch oil passage 104 of 3 is the L-H shift valve 3 that has been moved to the left.
5 is sent to the oil passage 105 through the groove of the spool 36, and the line pressure P1 acts on the left side of the FWD switching valve 40. The branch oil passage 106 of the oil passage 104 is connected to the right end of the REV switching valve 45, and holds the spool 46 in the left moving state by the line pressure P1. The branch oil passage 107 of the oil passage 103 is connected to the solenoid valve SC, and the line pressure P1 is also supplied to the solenoid valve SC.

As described above, the solenoid valves SA to S
The line pressure P1 is supplied to each of the F, and the supply of the hydraulic oil having the line pressure P1 can be controlled by opening / closing control of this valve.

First, the case of setting the 1ST shift speed will be described. Note that, as shown in Table 2, the solenoid valve SF is not involved in the setting of the shift speed, and therefore only the solenoid valves SA to SE will be considered here. In 1ST, as shown in Table 2, the solenoid valve SC is on, the others are off, only the solenoid valve SA is opened, and the other solenoid valves are closed. When the solenoid valve SA is opened, the line pressure P1 is supplied from the oil passage 125 to the oil passage 130, and the line pressure P1 is passed from the oil passage 130 to the oil passage 131 through the groove of the manual valve spool 26 located at the position D. Supplied.

The branched oil passage 131a of the oil passage 131 is connected to the right end of the relief valve 55, and the line pressure P1 acts on the right end of the relief valve 55. Furthermore, the oil passage 131
The line pressure P1 is supplied to the first clutch CL1 via the oil passage 132 that branches off from, and the first clutch CL1 is engaged. The change in the clutch pressure CL1 is adjusted by the first accumulator 71.

The second clutch CL2 is connected to the drain from the relief valve 55 (the spools 56 and 57 are in the right moving state at this time) via the solenoid valve SB, and the third clutch CL3 is connected to the drain via the solenoid valve SC. , The first brake B1 is connected to the drain from the relief valve 55 via the solenoid valve SC, and the second brake B2 is connected to the drain via the manual valve 25. Therefore, only the first clutch CL1 is engaged and
The ST speed stage is set.

Next, consider the case where the 2ND speed stage is set. At this time, the state of 1ST is the solenoid valve S
D is switched from OFF to ON, solenoid valve SD
Is also opened. As a result, the oil passage 123 to the oil passage 140
The line pressure P1 is supplied to the first brake B1 and the hydraulic oil having the line pressure P1 is supplied to the first brake B1 via the oil passage 141 from the relief valve 55 in the state where the spools 56 and 57 are moved to the right. Therefore, the first clutch CL1 and the first brake B1 are both engaged to set the 2ND speed stage.

When setting the 3RD speed stage, the solenoid valve SC is switched from on to off and the solenoid valve SD is returned to off. Solenoid valve S
Since D returns to off, the first brake B1 is released.
By switching off the solenoid valve SC,
This is released, and the hydraulic oil having the line pressure P1 is supplied from the oil passage 107 to the third clutch CL3 via the oil passage 145. As a result, the third clutch CL3 is engaged and 3
The RD speed stage is set. At this time, at the same time, the oil passage 145
The line pressure P1 acts on the left side of the delivery valve 50 via the oil passage 146 that branches off from, and the line pressure P1 acts on the right end of the relief valve 55 via the oil passage 147.

When setting the 4TH speed stage, the solenoid valve SB is switched from OFF to ON and the solenoid valve SC is returned to ON. Since the solenoid valve SC is turned back on, the third clutch CL3 is released. on the other hand,
By switching on the solenoid valve SB,
The solenoid valve SB is opened, the line pressure P1 is supplied from the oil passage 124 to the oil passages 150 and 151, and the second clutch C is passed from the groove of the spool 56 that has moved rightward via the oil passage 152.
The line pressure P1 is supplied to L2. Therefore, the second clutch CL2 is engaged and the 4TH speed stage is set.

When setting the 5TH speed stage, the solenoid valve SA is switched from off to on and the solenoid valve SC is switched from on to off. When the solenoid valve SA is switched from OFF to ON, the supply of the line pressure P1 to the oil passage 130 is cut off, the first clutch CL1 is connected to the drain via the solenoid valve SA, and the first clutch CL1 is released. . On the other hand, when the solenoid valve SC is switched off, the third clutch CL3 is engaged as described above, and as a result, the 5TH speed stage is set.

The engagement control of each clutch and brake is performed as described above. Here, by operating the shift lever from N to D, the N range (neutral range) to the D range (forward range). The engagement control in the case of switching to will be described based on the time chart shown in FIG. 5 and the flow charts shown in FIGS.

As shown in the flow chart, the presence or absence of switching from the N range to the D range is detected in the control device (step S2), and this control is not performed unless the D range is switched. When the switch to the D range is detected in step S2, the vehicle speed V is a predetermined vehicle speed b (a value close to zero) in step S4.
It is determined whether or not it is smaller than that, that is, whether or not it is almost stopped. This control is not performed even when the vehicle speed V is not substantially zero.

When the N range is switched to the D range when the vehicle speed V is substantially zero, the routine proceeds to step S6, where the first timer time t1 is set and, as shown in FIG.
As also shown, the solenoid valves SA and SC are turned off (step S8).
This control is performed for the first timer time t1 set in step S6 (step S10).

As a result, the normally open type solenoid valves SA and SC are in the fully open state, and the hydraulic oil is rapidly supplied to the first and third clutches CL1 and CL3 to fill the piston oil chambers with oil. The invalid stroke closing operation for moving the piston by the invalid stroke is rapidly started.

This state continues for the set time of the first timer t1, and when the set time of the first timer t1 has elapsed, the process proceeds from step S10 to step S12, the solenoid valve SC remains OFF, and the solenoid valve SA
The intermediate duty ratio signal is output to. The intermediate duty ratio signal is a duty ratio signal that generates a hydraulic pressure required to hold the clutch in a state immediately before engagement. As a result, the hydraulic oil supply to the first clutch CL1 is throttled, but the rapid supply is continued as it is to the third clutch CL3.

In this control, the engine speed N
e, the turbine rotation speed Nt of the torque converter and the rate of change dNt / dt of the turbine rotation are detected, and the difference ΔN (= Ne−N) between the engine rotation speed Ne and the turbine rotation speed Nt is detected.
t) has been calculated. Then, this difference ΔN becomes larger than the first allowable difference ΔN1 and the rate of change in turbine rotation dNt /
When it is determined in steps S14 and 16 that the absolute value of dt becomes larger than the first allowable rate RNt (1), it is determined that the invalid stroke closing of the third clutch CL3 is completed, and the solenoid valve SA sets the intermediate duty ratio to the intermediate duty ratio. As it is, the control shifts to the control for operating the solenoid valve SC based on the first duty ratio (step S18). The first duty ratio is a value slightly larger than the intermediate duty ratio, and is a duty ratio for generating a hydraulic pressure that can engage the third clutch CL3 to some extent. This makes the third
The clutch CL3 is held in a predetermined engagement state (gradual engagement state), and the third speed (3RD) is set.

Further thereafter, the difference ΔN between the engine speed Ne and the turbine speed Nt is the second allowable difference ΔN2 (ΔN2>
ΔN1) and the rate of change of turbine rotation dNt /
The absolute value of dt is the second permissible rate RNt (1) (RNt (2)> RNt
(2)) If it is determined in steps S20 and 22 that the value is greater than the above, it is determined that the invalid stroke closing of the first clutch CL1 is completed, the process proceeds to step S24, and the solenoid valve SC remains in the first duty ratio control. The control for operating the solenoid valve SA based on the feedback first duty ratio control is started. It should be noted that this feedback duty ratio control is performed by controlling the turbine speed Nt
And the feedback control with the turbine speed change rate dNt / dt as the target value.

This feedback control is performed by the first clutch C.
This is a control for gradually engaging L1, and as can be seen from this, at the time of shifting to step S24, the invalid stroke closing control shifts to the normal engagement control.

Thereafter, the turbine rotation speed Nt is equal to the predetermined rotation speed N.
When it is reduced to t (1), steps S26 to S2
8, the solenoid valve SA operates the solenoid valve SC based on the second duty ratio while the feedback duty ratio control is being performed. The second duty ratio is a duty ratio that further lowers the engagement hydraulic pressure P (CL3) of the third clutch CL3, and the third clutch CL3 is gradually released to shift to the first speed.

Then, when the turbine rotation change rate dNt / dt becomes substantially zero, steps S30 to S32 are performed.
Then, the second timer t2 is set and the solenoid valve SC is turned on (step S34). As a result, the third clutch CL3 is completely released. The second timer t2 is for waiting until the first clutch CL1 is completely engaged. When the set time of the second timer t2 elapses, the process proceeds from step S36 to step S38, and the solenoid valve SC remains ON and the solenoid Valve SA to O
Set to FF to maximize the engagement hydraulic pressure of the first clutch CL1. At this time, the first clutch CL1 is in the completely engaged state, and the shift shock does not occur even if the engagement hydraulic pressure becomes maximum. As described above, the in-gear squat control is smoothly performed.

In the control of FIG. 5, the solenoid valve SC is shifted to the first duty ratio control when the absolute value of the turbine rotation change rate dNt / dt becomes larger than the predetermined allowable rate RNt (s), and the solenoid The difference ΔN between the engine speed Ne and the turbine speed Nt of the valve SA is a predetermined allowable difference Δ.
It may be configured to shift from the intermediate duty ratio control to the feedback duty ratio control when it becomes larger than Ns. In this case, the rate of change of turbine rotation dN
The absolute value of t / dt becomes larger than the predetermined allowable rate RNt (s), and the difference ΔN between the engine speed Ne and the turbine speed Nt
Becomes larger than the predetermined allowable difference ΔNs, the invalid stroke reduction control is shifted to the normal engagement control.

In the above embodiment, the in-gear squat control for setting the starting gear (first gear) via the high gear (third gear) has been described as an example. The present invention is not limited to this, and control can be performed using the apparatus of the present invention even when the starting gear is directly set from the neutral range.

In the above embodiment, a plurality of planetary gears are used to form a plurality of power transmission paths, which are selected by friction engagement elements such as clutches and brakes for automatic gear shifting. Although the gear type automatic transmission has been described, the control device of the present invention can be used not only in such a gear type automatic transmission but also in a continuously variable type automatic transmission as shown in FIGS. 8 and 9. it can.

A continuously variable automatic transmission will be briefly described below. First, the automatic transmission shown in FIG. 8 includes a torque converter 202 connected to an output shaft 201 of an engine ENG, a forward / reverse switching mechanism 205 composed of a double pinion planetary gear connected to the output shaft, and a forward / backward switching. It comprises a continuously variable transmission mechanism 210 connected to the mechanism 205. Turbine shaft 2 of torque converter 202
The forward / reverse switching mechanism 205 connected to the 03 is the forward clutch 2
06 and a reverse brake 207, and a forward clutch 2
06 to set the forward range (select the forward power transmission path), engage the reverse brake 207 to set the reverse range (select the backward power transmission path), and release both of them. Then the neutral range can be set.

The continuously variable transmission mechanism 210 is composed of a drive pulley 211 and a driven pulley 212 whose pulley widths can be variably set by hydraulic pressure and the like, and a metal V belt 213 hung on these pulleys. Can be variably set to continuously change the gear ratio.

In the automatic transmission shown in FIG. 9, a transmission input shaft 303 is connected to the output shaft 201 of the engine ENG via a coupling 302. The transmission input shaft 30
A forward / reverse switching mechanism 305 similar to the above is connected to 3, and a continuously variable transmission mechanism 310 is connected to the forward / reverse switching mechanism 305. In this automatic transmission, the continuously variable transmission mechanism 310 is used.
A starting clutch 315 is connected to the output shaft 314 of the.

In this transmission, the forward clutch 3
06 to set the forward range (select the forward power transmission path), engage the reverse brake 307 to set the reverse range (select the backward power transmission path), and release the starting clutch 315. Then the neutral range can be set. A clutch similar to this starting clutch may be provided in the transmission shown in FIG.

Also in such a continuously variable automatic transmission, the switching control from the neutral range to the traveling range (forward range or reverse range) can be performed in the same manner as in the above embodiment. An example of such control is shown in FIG. 10. In this control, the invalid stroke reduction control is performed by turning on the solenoid valve for starting clutch control from when the shift command from the neutral range to the D range is output. Start. Then, the difference ΔN (= Ne−N between the engine speed Ne and the turbine speed Nt).
If it is determined in steps S14 and 16 that t) becomes larger than the first allowable difference ΔN1 and the absolute value of the turbine rotation change rate dNt / dt becomes larger than the first allowable rate RNt (1), the third clutch CL3 It is determined that the invalid stroke reduction of No. 1 is completed, and the control shifts to the engagement control for operating the solenoid valve for starting clutch control based on the first duty ratio.

[0059]

As described above, according to the present invention,
When the in-gear control is performed by switching from the neutral range to the travel range, first, the engagement operation control of the friction engagement element for setting the travel range is configured by a plurality of control stages including dead stroke reduction, and the coupling means output shaft (Or torque converter turbine shaft) The absolute value of the change rate of rotation is greater than or equal to a predetermined rate of change and the difference between the engine speed and the rotational speed of the coupling output shaft (turbine shaft) is greater than or equal to a predetermined value. Since it is configured to end the invalid stroke closing control, it is possible to accurately determine whether the invalid stroke closing is completed regardless of the depression state of the accelerator pedal. Further, even when the engine rotation fluctuates up and down to some extent during the in-gear control, it is possible to accurately determine the completion of the invalid stroke reduction.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an automatic transmission in which shift control is performed by a shift control device according to the present invention.

FIG. 2 is a hydraulic circuit diagram that constitutes a shift control device according to the present invention.

FIG. 3 is a hydraulic circuit diagram that constitutes a shift control device according to the present invention.

FIG. 4 is a hydraulic circuit diagram that constitutes a shift control device according to the present invention.

FIG. 5 is a graph showing changes over time in operating states of solenoid valves and various variables in shift control by the shift control device according to the present invention.

FIG. 6 is a flowchart showing shift control contents by the shift control device according to the present invention.

FIG. 7 is a flowchart showing shift control contents by the shift control device according to the present invention.

FIG. 8 is a schematic diagram showing a different example of an automatic transmission in which shift control is performed by the shift control device according to the present invention.

FIG. 9 is a schematic diagram showing still another example of an automatic transmission in which shift control is performed by the shift control device according to the present invention.

10 is a graph showing changes with time of various variables in the shift control by the shift control device for the transmission shown in FIG. 8 or FIG.

[Explanation of symbols]

 3 Transmission input shaft 4 Transmission output gear 10 Hydraulic pump 20 Regulator valve 25 Manual valve 30 Reducing valve 35 L-H shift valve 40 FWD switching valve 45 REV switching valve 50 Delivery valve 55 Relief valve

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location F16H 63:06 63:12 (72) Inventor Hisashi Kunii 1-4-1 Chuo, Wako, Saitama Incorporated company Honda R & D Co., Ltd. (72) Inventor Noriyuki Ura 1-4-1 Chuo, Wako-shi, Saitama Incorporated Honda R & D Co., Ltd. (72) Inventor Takamichi Shimada 1-4-4 Wako, Saitama No. 1 Stock Company Honda Technical Research Institute

Claims (4)

[Claims] 1. A coupling means connected to an output shaft of an engine, a speed change mechanism connected to an output shaft of the coupling means, and a friction engagement element capable of setting at least a traveling range and a neutral range in the speed change mechanism. In a shift control device for an automatic transmission, which comprises an engagement control means for controlling engagement operation of the friction engagement element, the engagement control means provides a hydraulic pressure command to an engagement operation hydraulic pressure of the friction engagement element. Engagement operation control is performed by controlling according to a signal, and when the neutral range is switched to the travel range, the engagement control means is an engagement operation of the friction engagement element for setting the travel range. After the invalid stroke closing control for setting the hydraulic pressure to a predetermined high pressure is started, and after the invalid stroke closing control is started, the rotation change rate of the output shaft of the coupling means is stopped. When the pair value is equal to or more than a predetermined change rate and the difference between the rotation speed of the engine and the rotation speed of the output shaft of the coupling means is equal to or more than a predetermined value, it is determined that the invalid stroke closing is completed, and the invalid stroke closing control ends A shift control device for an automatic transmission, wherein the engagement actuation hydraulic pressure is set to a hydraulic pressure lower than the predetermined high pressure. 2. The coupling means comprises a torque converter, and the absolute value of the rotational change rate of the turbine shaft of the torque converter is equal to or greater than a predetermined change rate and the difference between the rotational speed of the engine and the rotational speed of the turbine shaft. The invalid stroke closing is determined to be completed when the value is equal to or more than a predetermined value, and the invalid stroke closing control is ended.
A shift control device for an automatic transmission as set forth in. 3. The shift mechanism comprises a plurality of power transmission paths having different gear ratios, and the friction engagement element has a plurality of friction engagement elements for selecting and setting a predetermined power transmission path from the plurality of power transmission paths. When the neutral range is switched to the travel range, the engagement control means is configured to set a friction transmission for setting a power transmission path, which is set for starting of the plurality of power transmission paths. After starting the invalid stroke closing control for setting the engagement hydraulic pressure of the coupling element to a predetermined high pressure, and after starting the invalid stroke closing control, the absolute value of the rotation change rate of the turbine shaft of the torque converter is equal to or more than the predetermined change rate. When the difference between the rotation speed of the engine and the rotation speed of the turbine shaft is equal to or more than a predetermined value, it is determined that the invalid stroke closing is completed, and the invalid stroke closing control is ended. To shift control device for an automatic transmission according to claim 2, characterized in that to set the engagement actuation pressure to a lower pressure than the predetermined pressure. 4. The transmission mechanism is a continuously variable transmission mechanism,
3. The shift control of the automatic transmission according to claim 1, wherein the friction engagement element is a start control friction engagement element capable of setting at least a traveling range and a neutral range in the continuously variable transmission mechanism. apparatus.