JPH0727214A - Transmission control method or automatic transmission - Google Patents

Abstract

PURPOSE:To reduce transmission shock by preventing generation of residual pressure in a releasing chamber. CONSTITUTION:A frictional fastening element has a fastening chamber 38b and a releasing chamber 38c sandwiching a piston 38a. The frictional fastening element is fastened, when pressure oil is supplied only to the fastening chamber 38b, and the fastening is released when the pressure oil is supplied to both the fastening chamber 38b and the releasing chamber 38c, or when the pressure oil is discharged from the chambers 38b, 38c. When shifting is performed from the stage where the pressure oil is supplied to the releasing chamber 38c of the frictional fastening element and to the stage where the pressure oil is discharged from both chambers 38b, 38c, transmission is performed through a condition that the pressure oil is supplied to the fastening chamber 38b and the pressure oil in the releasing chamber 38c is positively discharged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for an automatic transmission.

[0002]

2. Description of the Related Art Generally, an automatic transmission for an automobile has a combination of a torque converter and a speed change mechanism and a power transmission path of the speed change mechanism such as a clutch or a clutch, as disclosed in, for example, Japanese Patent Laid-Open No. 63-186055. It is configured such that a plurality of frictional engagement elements such as a brake are selectively operated to switch the gears and automatically shift to a predetermined gear.

And, as the friction fastening element,
A 2-4 clutch is provided which is engaged at the 2nd speed and the 4th speed. This clutch is, for example, as shown in FIG.
As shown in (a), a fastening chamber b and a release chamber c are provided in front of and behind the piston a, and pressure oil is supplied only to the fastening chamber b at the second speed stage or the fourth speed stage to establish the engaged state. Becomes 3
Pressure oil is supplied to both the fastening chamber b and the release chamber c at the time of the first speed shift stage to be in the released state, and both the chambers b and c are released at the first speed stage to be in the released state. Has been done. 10 (a-1) shows the state of the third speed shift stage, (a-2) shows the state of the first speed shift stage, and (a-
3) shows a state in the middle of a shift from the first gear to the second gear. Further, FIG. 10B shows a change state of the hydraulic pressure in each chamber when shifting from the third shift stage to the second shift stage through the first shift stage, and the change state of the hydraulic pressure in the fastening chamber b is indicated by a broken line. B
Then, the change state of the hydraulic pressure in the release chamber c is shown by a one-dot chain line C, respectively. For comparison with these changes, FIG.
In (b), the solid line A shows the change state of the hydraulic pressure of the 3-4 clutch.
Indicate.

[0004]

However, in the above-mentioned conventional 2-4 clutch, the piston b does not move smoothly when shifting from the 1st gear to the 2nd gear, and the shift timing of the clutch is delayed to shift the gear. A shock may occur, which occurs particularly when shifting from the third speed to the first speed and then to the second speed. This is because the pressure oil in the release chamber c is released from the pressure during the shift from the third gear to the first gear, but the oil itself remains, and the oil remains from the first gear to the second gear. This is because the piston a is compressed by the movement to the side of the release chamber c at the time of shifting to the high speed shift stage to generate pressure so-called residual pressure (FIG. 10).
(See (b)).

The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent generation of residual pressure in the release chamber c and reduce shift shock. It is intended to provide a shift control method of

[0006]

In order to achieve the above object, the solution means of the present invention comprises a frictional fastening element having a fastening chamber and a release chamber provided in front of and behind the piston, and the frictional fastening element is It is configured to be engaged when pressure oil is supplied only to the fastening chamber and to release the fastening when pressure oil is supplied to both the fastening chamber and the release chamber or when the pressure oil is removed from both chambers. Targets automatic transmissions. Then, when shifting from a shift stage in which pressure oil is supplied to the release chamber of the friction engagement element to a shift stage in which pressure oil is removed from both chambers, pressure oil is supplied to the engagement chamber to release pressure oil in the release chamber. The gear is configured to be shifted through a state in which is actively excluded.

[0007]

With the above-described structure, in the present invention, the speed change stage (third speed change speed, etc.) in which pressure oil is supplied to the release chamber of the friction engagement element is such that the pressure oil is removed from both the engagement chamber and the release chamber. When shifting to the 1st gear, etc., the speed is changed via the state in which pressure oil is supplied to the fastening chamber and the pressure oil in the release chamber is positively removed, so the amount of oil remaining in the release chamber must be reduced. You can Therefore, no residual pressure is generated in the release chamber when shifting from the shift stage to a shift stage (second shift stage or the like) in which pressure oil is supplied only to the engagement chamber, and the switching timing of the friction engagement element is delayed. It is done smoothly.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an automatic transmission AT having four forward gears and one reverse gear for an automobile. The automatic transmission AT is a main constituent element for changing the torque of the engine output shaft 1 (engine torque). The torque converter 3 that transmits to the turbine shaft 2 and the speed change gear mechanism 5 that further changes the torque of the turbine shaft 2 and reverses the rotation when the reverse gear is selected and outputs the output gear 4 to the drive wheel side. And have. The turbine shaft 2 is formed in a pipe shape, and a pump shaft 6 connected to the engine output shaft 1 is disposed in the hollow portion of the turbine shaft 2. )
The oil pump 7 arranged at is driven to rotate.

The torque converter 3 has a pump 12 fixed in a case 11 connected to the engine output shaft 1.
And the turbine shaft 2 facing the pump 12.
And a stator 13 that is connected to the turbine 13 and is rotationally driven by hydraulic fluid discharged from the pump 12, and a stator 14 that rectifies the hydraulic fluid that flows back from the turbine 13 to the pump 12 in a direction that promotes rotation of the pump 12. , Pump 1
The torque of the engine output shaft 1 is changed at a speed change ratio according to the difference in rotation speed between the turbine 2 and the turbine 13. The stator 14 is fixed to a transmission case 16 via a stator one-way clutch 15. Reference numeral 17 denotes a lockup clutch 17 that directly connects the engine output shaft 1 and the turbine shaft 2 as needed.

On the other hand, the speed change gear mechanism 5 is composed of a Ravigneaux type planetary gear device, and has a small diameter small sun gear 21 loosely fitted in the turbine shaft 2 and a small sun gear 21 rearwardly of the small sun gear 21 and also in the turbine shaft 2. The large sun gear 22 having a large diameter fitted therein, a plurality of short pinion gears 23 (only one is shown) that mesh with the small sun gear 21, a front portion (right side in FIG. 1) meshes with the short pinion gear 23, and a rear portion has the large Long pinion gear 24 that meshes with sun gear 22
A carrier 25 that rotatably supports the short pinion gear 23 and the long pinion gear 24, and a ring gear 26 that meshes with the long pinion gear 24. In such a speed change gear mechanism 5, the small sun gear 21, the large sun gear 22 or the carrier 25 serves as a torque input section according to the gear stage, while the ring gear 26 serves as a torque output section at any gear stage. The ring gear 26 is connected to the output gear 4.

In order to switch the torque transmission path in the speed change gear mechanism 5, that is, to change the gear ratio or the rotation direction of the output gear 4, clutches and brakes as a plurality of friction engagement elements are provided. Has been.

That is, a forward clutch 31 is provided between the turbine shaft 2 and the small sun gear 21.
And the first one-way clutch 41 are provided in series, and the coast clutch 32 is provided in parallel with the both clutches 31, 41. A 3-4 clutch 33 is provided between the turbine shaft 2 and the carrier 25, and a reverse clutch 34 is provided between the turbine shaft 2 and the large sun gear 22. Between the reverse clutch 34 and the reverse clutch 34, a 2-4 brake 35, which is a band brake for fixing the large sun gear 22 at a predetermined speed, is provided. Further, between the carrier 25 and the transmission case 16, a low reverse brake 36 for fixing the carrier 25 at a predetermined speed and a second one-way clutch 42 for receiving a reaction force of the carrier 25 are provided in parallel. Has been done. In the following description, the various clutches 31 to 34 and the brakes 35 and 36 will be collectively referred to as "friction engagement elements" as appropriate.

By changing the engaging / disengaging patterns of the friction engaging elements 31 to 36, various ranges or shift speeds as shown in Table 1 can be obtained. Hereinafter, with reference to Table 1, a torque transmission path in each range or shift stage and its shift characteristics will be described.

[0015]

[Table 1] (1) In the P range (parking range), all the friction engagement elements are turned off (released). In this case, the torque of the turbine shaft 2 is not transmitted to the speed change gear mechanism 5.

(2) In the case of the R range (reverse range), the reverse clutch 34 and the low reverse brake 36
Are fastened and the other frictional fastening elements are released. Since the low reverse brake 36 is engaged, the second one-way clutch 42 arranged in parallel with the low reverse brake 36 does not exert any special action. The first one-way clutch 41 is disengaged from the torque transmission path and does not exert any special action.

In this case, the torque of the turbine shaft 2 is transmitted through the reverse clutch 34 to the large sun gear 22.
Entered in. Since the carrier 25 is fixed by the low reverse brake 36, the large sun gear 22, the long pinion gear 24, and the ring gear 26 function as a fixed gear train that meshes in this order.
Therefore, the torque input to the large sun gear 22 is transmitted through the gear train in the order described above, and is shifted at a large reduction ratio determined by the number of teeth of the large sun gear 22 and the number of teeth of the ring gear 26, and the torque is input to the output gear 4. Is output. This R
In the range, the ring gear 26 (output gear 4) rotates in the direction opposite to the large sun gear 22 (turbine shaft 2), and the drive wheels are driven to the reverse side.

(3) N range (neutral range)
The case is the same as the case of the P range.

(4) In the first speed in the D range (drive range), the forward clutch 31 is engaged and the other friction engagement elements are released. The first and second one-way clutches 41, 42 are normally locked, but idle during coasting.

In this case, the torque of the turbine shaft 2 is input to the small sun gear 21 via the forward clutch 31 and the first one-way clutch 41 in order. Since the carrier 25 is fixed by the second one-way clutch 42, the small sun gear 21
And short pinion gear 23 and long pinion gear 24
And the ring gear 26 function as a fixed gear train that meshes in this order. Therefore, the torque input to the small sun gear 21 is transmitted through the gear train in the above order,
The gear is changed at a large reduction ratio determined by the number of teeth of the small sun gear 21 and the number of teeth of the ring gear 26, and is output to the output gear 4. In this case, the ring gear 26 (output gear 4) rotates in the same direction as the small sun gear 21 (turbine shaft 2), and the drive wheels are driven forward. still,
At the first speed in the D range, engine braking cannot be obtained due to the action of the first one-way clutch 41.

(5) In the D range second speed, the forward clutch 31 and the 2-4 brake 35 are engaged, and the other friction engagement elements are released. 1st one-way clutch 4
1 is normally locked, but idles during coasting. The second one-way clutch 42 always idles.

In this case, since the large sun gear 22 is fixed, the long pinion gear 24 revolves around the large sun gear 22 while rotating on its axis. Therefore, basically, the torque is transmitted through the same route as in the case of the first speed in the D range, but the rotational speed of the ring gear 26 increases by the amount of revolution of the long pinion gear 24, so that the speed is slightly reduced as compared with the first speed in the D range. The ratio becomes smaller. In the second speed in the D range, engine braking cannot be obtained due to the action of the first one-way clutch 41.

(6) In the third range of the D range, the forward clutch 31, the coast clutch 32 and the 3-4 clutch 33 are engaged and the other friction engagement elements are released. Since the coast clutch 32 is engaged, the forward clutch 31 and the first one-way clutch 41, which are arranged in parallel with the coast clutch 32, have no particular effect. The second
The one-way clutch 42 always idles.

In this case, since the small sun gear 21 and the carrier 25 are locked to each other via the coast clutch 32, the turbine shaft 2 and the 3-4 clutch 33, all the gears and the carrier 2 of the planetary gear device.
1 to 26 will rotate integrally with the fixed state,
The turbine shaft 2 and the output gear 4 are directly connected. Therefore, the torque of the turbine shaft 2 is transmitted to the output gear 4 without being shifted (reduction ratio 1). In this case, the output gear 4 rotates in the same direction as the turbine shaft 2, and the drive wheels are driven forward. In the third speed of the D range, the turbine shaft 2 and the output gear 4 are directly connected to each other, so that engine braking can be obtained.

(7) In the 4th speed of the D range, the forward clutch 31, the 3-4 clutch 33, and the 2-4 brake 3
5 is fastened and the other friction fastening elements are released. First
Also, the second one-way clutches 41 and 42 always idle. Since the first one-way clutch 41 always idles, the forward clutch 31 is engaged,
It has no special effect.

In this case, the torque of the turbine shaft 2 is input to the carrier 25 via the 3-4 clutch 33, and the torque of the carrier 25 is sequentially output to the output gear 4 via the long pinion gear 24 and the ring gear 26. Transmitted. Since the large sun gear 22 is fixed by the 2-4 brake 35, the long pinion gear 24
Revolves around the large sun gear 22 while rotating. Therefore, the rotation speed of the ring gear 26 becomes higher than the rotation speed of the carrier 25, that is, the rotation speed of the turbine shaft 2 by the amount of revolution of the long pinion gear 24.
Is in the overdrive (acceleration) state. The ring gear 26 (output gear 4) rotates in the same direction as the carrier 25 (turbine shaft 2), and the drive wheels are driven forward.

(8) In the case of the S range first speed, the D range 1
It is similar to the case of speed.

(9) In the S range second speed, the forward clutch 31, the coast clutch 32 and the 2-4 brake 35 are engaged, and the other friction engagement elements are released. Since the coast clutch 32 is engaged, the forward clutch 31 and the first one-way clutch 41, which are arranged in parallel with the coast clutch 32, have no particular effect.

In this case, the torque transmission path and the speed change characteristic are basically the same as those in the case of the second speed in the D range, but the first one-way clutch 41 does not work, so engine braking can be obtained.

(10) The case of the S range third speed is the same as the case of the D range third speed.

(11) In the L range first speed, the forward clutch 31, the coast clutch 32, and the low reverse brake 36 are engaged, and the other friction engagement elements are released. Since the coast clutch 32 is engaged, the forward clutch 31 and the first clutch arranged in parallel therewith
The one-way clutch 41 does not exert any particular effect, and the low reverse brake 36 is engaged. Therefore, the second one-way clutch 42 arranged in parallel with the one-way clutch 41,
It has no special effect.

In this case, the torque transmission path and the speed change characteristic are basically the same as those in the first speed of the D range, but the first and second one-way clutches 41 and 42 do not work, so engine braking can be obtained. It will be.

(12) The case of the L range second speed is the same as the case of the S range second speed.

Next, a hydraulic control circuit 60 for supplying / discharging hydraulic pressure to / from the actuators of the friction engagement elements 31-36 of the speed change gear mechanism 5 to engage / disengage will be described with reference to FIGS. Here, among the above actuators, the hydraulic actuator 38 of the 2-4 brake 35
Is the fastening chamber 38b and the release chamber 38 before and after the piston 38a.
c is a servo piston type, and the 2-4 brake 35 is engaged when hydraulic pressure is supplied only to the fastening chamber 38b, and hydraulic pressure is supplied to both chambers 38b and 38c, or both hydraulic pressures are applied. Is removed (released) by the urging force of the spring 38d and the like. Other friction fastening elements 31 to 3
The actuators 4, 36 are composed of ordinary hydraulic pistons, and when the hydraulic pressure is supplied, the friction engaging elements are engaged, and when the hydraulic pressure is removed, the friction engaging elements are released.

The hydraulic control circuit 60 has, as main components, a regulator valve 61 for adjusting the hydraulic pressure of the hydraulic oil discharged from the oil pump 7 shown in FIG. 1 to the main line 110 to a predetermined line pressure, and a manual operation. The manual valve 62 for selecting the range by the gears, and the friction engagement elements (actuators) 3 that are activated according to the gears.
1-2, 2-3, 3 for supplying / discharging hydraulic pressure to 1-36
-4 shift valves 63, 64, and 65 are provided.

As shown in FIG. 4, the manual valve 62 includes an input port 62e into which a line pressure is introduced from the main line 110 and first to fourth output ports 62a to 6a.
2d, and by moving the spool, the input port 62e becomes the first and second output ports 62a and 62b in the D range and the S range, and becomes the first and third output ports 62a and 62c in the L range. In the R range, the fourth output port 62d communicates with each other. The output ports 62a to 62d are connected to the first to fourth output lines 111 to 114, respectively. Also,
As shown in FIGS. 4 and 5, the above-mentioned 1-2, 2-3 and 3
Each of the -4 shift valves 63, 64, and 65 has a structure in which the spool is biased to the right side in the drawing by a spring (not shown), and the pilot chamber 6 is provided to the right side of these spools.
It has 3a, 64a, and 65a.

In the pilot chambers 63a and 64a of the 1-2 shift valve 63 and the 2-3 shift valve 64,
First and second pilot lines 115, 116 branched from the main line 110 are connected to the pilot chamber 65a of the 3-4 shift valve 65, and a third pilot line branched from the second pilot line 116. 117 is connected to the pilot lines 115 to 117, and first, second and third solenoid valves 66 and 6 for shifting are respectively connected to these pilot lines 115 to 117.
7, 68 are provided. Each solenoid valve 6
6 to 68 eliminate the hydraulic pressure (pilot pressure) in the pilot chambers 63a to 65a of the corresponding shift valves 63 to 65 when all of the shift valves 63 to 6 are turned on.
The spool of No. 5 is located on the right side in the drawing (state shown in the upper half of the axis), and when it is off, the pilot chambers 63a to 65a of the corresponding shift valves 63 to 65 are piloted from pilot lines 115 to 117 from pilot lines 115 to 117. Pressure is introduced to position the spools of the shift valves 63 to 65 on the left side of the drawing (state shown in the lower half of the axis).

On the other hand, among the first to fourth output lines 111 to 114 connected to the output ports 62a to 62d of the manual valve 62, the main line 110 is communicated with each forward range of D, S and L. A line 119 is branched from the first output line 111, and the line 119 branches off.
Is called a forward clutch line and is guided to the forward clutch 31 via a one-way orifice 71. Therefore, the forward clutch 31 is always engaged in the D, S, and L ranges. The branch line 120 of the forward clutch line 119 is connected to an accumulator 72 for buffering when the forward clutch is engaged.

The first output line 111 is guided to the 1-2 shift valve 63, the first solenoid valve 66 is turned on, and the spool of the shift valve 63 is positioned on the right side. 121, the fastening chamber 38b of the 2-4 brake 35 through the one-way orifice 73 and the exhaust pressure control valve 74.
Leading to. Therefore, when the first solenoid valve 66 is on in the D, S, and L ranges, hydraulic pressure (servo apply pressure) is introduced into the engagement chamber 38b. The one-way orifice 73 is set to have a diameter such that the hydraulic oil is appropriately throttled and discharged when the servo apply pressure is discharged.
The discharge pressure control valve 74 is configured to quickly discharge the hydraulic oil at the start of discharging the servo apply pressure, and gently discharge the hydraulic oil when the servo fly pressure falls to a predetermined pressure. In addition, the above-mentioned Appla Import 35b
A line 122 is connected to the accumulator 75 for buffering the 2-4 brake.

The first output line 111 is further 3-4.
The third solenoid valve 6 is also guided to the shift valve 65.
When 8 is off and the spool of the shift valve 65 is located on the left side, it communicates with the coast clutch line 123.
The coast clutch line 123 reaches the coast clutch 32 via the coast reducing valve 76 and the one-way orifice 77. Therefore, the coast clutch 32 is engaged when the third solenoid valve 68 is off in the D, S, and L ranges.

On the other hand, in the D and S ranges, the main line 110
The second output line 112, which communicates with the, is led to the 2-3 shift valve 64. The line 112 is provided with the second solenoid valve 67 off and the 2-3 shift valve 6
When the 4th spool is located on the left side, it communicates with the 3-4 clutch line 124. The line 124 further reaches the 3-4 clutch 33 via the one-way orifice 78. Therefore, when the second solenoid valve 67 is off in the D and S ranges, the 3-4 clutch 33 is engaged. An accumulator 79 for buffering the engagement of the 3-4 clutch 33 is connected to the branch line 125 of the 3-4 clutch line 124.

A line 126 is branched from the 3-4 clutch line 124, and the line 126 is 3-lined.
The third solenoid valve 6 is guided to the 4th shift valve 65.
When 8 is off and the spool of the shift valve 65 is located on the left side, it communicates with the servo release line 127 which communicates with the release chamber 38c of the 2-4 brake 35. Therefore, D,
When both the second and third solenoid valves 67 and 68 are off in the S range, pressure oil (servo release pressure) is introduced into the release chamber 38c of the 2-4 brake 35, and the 2-4 brake 35 is released.

In the manual valve 62, the third output line 113 communicating with the main line 110 in the L range has a low reducing valve 80, a one-way orifice 81, a ball valve 82 and a line 128.
It is guided to the 1-2 shift valve 63 via. The line 128 communicates with a low reverse brake line 129 that communicates with the low reverse brake 36 when the first solenoid valve 66 is off and the spool of the 1-2 shift valve 63 is located on the left side. Therefore, when the first solenoid 66 is off in the L range, the low reverse brake 36 is engaged.

Further, the fourth output line 114 communicating with the main line 110 in the R range is a 1-2 shift valve 63 via the line 130 branched from the line 114, the one-way orifice 83, the ball valve 82 and the line 128. When the first solenoid valve 66 is turned off and the spool of the 1-2 shift valve 63 is located on the left side, the first reverse solenoid valve 66 is connected to the low reverse brake line 129. The output line 114 serves as a reverse clutch line 131 and reaches the reverse clutch 34. Therefore, in the R range, the low reverse brake 36 is engaged while the first solenoid valve 66 is off, while the reverse clutch 34 is always engaged. A line 132 branched from the line 130 between the one-way orifice 83 and the ball valve 82 is connected to an accumulator 84 for buffering when the reverse clutch is engaged.

Further, as shown in FIG. 6, the hydraulic control circuit 60 is provided with a lockup shift valve 85 for operating the lockup clutch 17 in the torque converter 3, and the lockup shift valve 85. A lock-up control valve 86 for adjusting the hydraulic pressure supplied to the torque converter 3 is provided. A pilot line 133 for guiding the hydraulic pressure (pilot pressure) from a solenoid reducing valve 87 (see FIG. 3) that reduces the hydraulic pressure of the main line 110 to a constant pressure is connected to the pilot chamber 86a at one end of the lockup control valve 86. The pilot line 133 is provided with a first duty solenoid valve 88 near the lockup control valve 86.

The lock-up shift valve 85 includes:
A torque converter line 134 guided from the regulator valve 61 via a converter relief valve 89 (see FIG. 3) is connected, and a line 11 is provided in a pilot chamber 85a at one end of the shift valve 85.
A pilot line 135 communicating with the main line 110 is connected via 5, and the pilot line 135 is provided with a solenoid valve 90 for lockup. When the solenoid valve 90 is off, the spool of the lockup shift valve 85 is located on the left side, so that the torque converter line 134 communicates with the lockup release line 1 in the torque converter 3.
36, whereby the lockup clutch 17 is completely released.

On the other hand, when the solenoid valve 90 is turned on and the spool of the lockup shift valve 85 moves to the right, the torque converter line 134 communicates with the converter inline 137 and the lockup release line 136 is connected to the line. It communicates with the lockup control valve 86 via 138. Then, by adjusting the pilot pressure introduced from the pilot line 133 into the pilot chamber 86a of the lockup control valve 86 by the first duty solenoid 88, the converter in-line 1
The differential pressure between the engagement pressure introduced via 37 and the release pressure introduced via the lock-up release line 136 is controlled, and the lock-up clutch 17 is controlled to the complete engagement state or a predetermined slip state.

Further, as shown in FIG. 3, the hydraulic control circuit 60 includes a throttle module for generating a throttle modulator pressure according to the engine load by operating the second duty solenoid valve 91 for controlling the line pressure. A regulator valve 92 is provided, and the throttle modulator pressure generated by the throttle modulator valve 92 is supplied to the regulator valve 61 via a line 139, and also via a line 140 branched from the line 139. It is introduced into a pilot chamber 76a provided at one end (left end in the drawing) of the spool of the coast reducing valve 76 (see FIG. 5). A hydraulic pressure (coast clutch pressure) downstream of the coast clutch line 123 of the valve 76 is fed back to a pilot chamber 76b provided at the other end (right end in the figure) of the spool of the coast reducing valve 76. The line 141 connected to the intermediate portion of the coast reducing valve 76 is guided to the 2-3 shift valve 64, and the second solenoid valve 67 is turned on so that the spool of the shift valve 64 is located on the right side. When the line 141 is connected to the main line 110
In communication with 42, the main pressure works together with the throttle modulator pressure to urge the spool to the right in the drawing. As a result, when the second solenoid valve 67 is on, the coast clutch pressure is increased and the shared torque of the coast clutch 32 is increased. On the other hand, when the second solenoid valve 67 is off, the
The spool of the -3 shift valve 64 moves to the left, and the communication between the lines 141 and 142 is cut off. As a result, the increased state of the coast clutch pressure is suppressed, and the shared torque of the coast clutch 32 is reduced. In addition, the regulator valve 61 is used to adjust the throttle modulator pressure.
An accumulator 93 for buffering when the hydraulic pressure is supplied is connected to the line 139 for supplying the oil.

In addition to the above configuration, as shown in FIGS. 3 and 4, the hydraulic control circuit 60 includes a bypass valve 94 and a 3-2 timing valve 95 for adjusting the hydraulic pressure supply / discharge timing at the time of shifting. And are provided. The bypass valve 94 is provided on a bypass line 143 that bypasses the one-way orifice 78 on the 3-4 clutch line 124, and a pilot chamber provided at one end (right end in the figure) of the spool of the bypass valve 94. The hydraulic pressure (3-4 clutch pressure) downstream of the one-way orifice 78 of the 3-4 clutch line 124 is introduced into 94a. Further, in the pilot chamber 94b provided at the other end (the left end in the figure) of the spool of the bypass valve 94, a throttle generated by the throttle modulator valve 92 is provided via a line 144 branched from the line 140. Modulator pressure is introduced. When the 3-4 clutch pressure rises above a predetermined pressure and the spool moves to the left, the bypass line 143 is cut off. Therefore, the 3-4 clutch pressure is promptly supplied through the bypass line 143 at the start of supply, and thereafter, the supply is moderated by the one-way orifice 78. In this way, the engagement timing of the 3-4 clutch 33 during the 2-3 upshift is adjusted, and the timing is changed according to the throttle opening of the engine.

Further, the above 3-2 timing valve 95
Is installed on a bypass line 145 that bypasses the one-way orifice 73 and the exhaust pressure control valve 74 on the servo apply line 121 guided from the 1-2 shift valve 63. This timing valve 95
A pilot line 146 branched from the main line 110 is connected to a pilot chamber 95a at one end (right end in the figure) of the main chamber 110, and a solenoid valve 96 for bypass control is connected to the pilot line 146. When the solenoid valve 96 is on and the spool of the timing valve 95 is located on the right side,
While hydraulic oil is quickly supplied to the engagement chamber 38b of the 2-4 brake 35 through the bypass line 145, when the solenoid valve 96 is turned off and the spool of the timing valve 95 is located on the left side, the bypass line 1
45 is shut off and the one-way orifice 73 is used to gently supply the hydraulic oil to the engagement chamber 38b of the 2-4 brake 35. The timing valve 95
The pilot pressure introduced to the pilot chamber 95a is also introduced into the pilot chamber 80a at one end of the low reducing valve 80 (see FIG. 6) through the pilot line 147. Therefore, when the solenoid valve 96 is turned on, the third output line 113 is shut off by the low reducing valve 80, and the low reverse brake 36
Will be delayed.

On the other hand, the 2-3 shift valve 64 has
A drain port 64c that communicates with the 3-4 clutch line 124 when the spool is located on the right side is provided, and a first drain line 148 is connected to the drain port 64c. Further, a second drain line 149 (see FIG. 3) is branched from the first drain line 148, the second drain line 149 is guided to the timing valve 95, and the spool of the timing valve 95 is When located on the right side, the second drain line 149 communicates with the drain port 95b provided in the timing valve 95. Therefore, when the second solenoid valve 67 is on and the 2-3 shift valve 64 is located on the right side, the 3-4 clutch 3
The 3-4 clutch line 124 leading to 3 communicates with the first drain line 148. As a result, the 3-4 clutch pressure is discharged from the first drain line 148 relatively slowly. On the other hand, when the bypass control solenoid valve 96 is turned on in this state to move the spool of the timing valve 95 to the right, the first drain line 148 is connected to the drain port 95b of the timing valve 95 via the second drain line 149. Since they are communicated with each other, the 3-4 clutch pressure is quickly discharged from both the first and second drain lines 148 and 149.

Here, as shown in FIG. 7, all the solenoid valves of the hydraulic control circuit 60, that is, the first to third solenoid valves 66 to 68 for shifting, the lockup solenoid valve 90, and the bypass control solenoid. Valve 96 and first and second duty solenoid valve 8
Reference numerals 8 and 91 denote a controller 200 as a shift control means.
The operation is controlled by. The controller 200 includes a signal from a vehicle speed sensor 201 that detects a vehicle speed of an automobile equipped with an automatic transmission AT and a throttle opening sensor 2 that detects a throttle opening of an engine.
02, a signal from a shift position sensor 203 that detects the position (range) of a shift lever (not shown) provided in the automatic transmission AT, and a turbine that detects the turbine speed of the torque converter 3. Speed sensor 2
04, a signal from an oil temperature sensor 205 that detects the temperature of hydraulic oil, and ON when the accelerator pedal is depressed.
A signal from the operating accelerator switch 206 is input. And the above control 2
00 is an on / off control for each shift solenoid valve 66-68 based on a map preset according to the vehicle speed of the automobile and the throttle opening of the engine for each range selected by the shift lever. To do. As a result, the spool positions of the shift valves 63 to 65 are switched, the friction engagement elements 31 to 36 are engaged in the combinations shown in Table 1, and the shift speed is switched according to the operating state. In this case, the relationship between each range or shift stage and the on / off combination pattern of the solenoid valves 66 to 68 for shifting is set as shown in Table 2.

[0053]

[Table 2] Next, referring to Table 2, each traveling range (R, D, S,
The hydraulic pressure supply path in the hydraulic pressure control circuit 60 in the L range) or the shift stage will be described.

(1) In the R range, the manual valve 62 takes the R range position, the first and second solenoid valves 66 and 67 are turned off, and the third solenoid valve 6
8 is turned on.

In this case, the fourth output line 114 communicates with the main line 110 to supply hydraulic pressure (line pressure) to the output line 114, and this hydraulic pressure is supplied to the reverse clutch 34 via the reverse clutch line 131. The reverse clutch 34 is engaged. In addition, the hydraulic pressure in the fourth output line 114 is 3-4 shift valve 65 in order.
Is supplied to the low reverse brake 36 via the ball valve 82, the line 128, the 1-2 shift valve 64, and the low reverse brake line 129, and the low reverse brake 36 is engaged. The other frictional fastening elements are released as no hydraulic pressure is supplied.

(2) In the first speed of the D range, the manual valve 62 takes the D range position (FIG. 4 shows this state), and the first and second output lines 111 and 112 communicate with the main line 110. Both output lines 111, 112
Is supplied with hydraulic pressure. In addition, this is the following D range 2-4
The same is true at high speed. Then, the first solenoid valve 66
Is turned off, and the second and third solenoid valves 67, 68 are turned on.
Is turned on.

In this case, the hydraulic pressure in the first output line 111 is supplied to the forward clutch 31 via the forward clutch line 119, and the forward clutch 31 is engaged. Further, since the hydraulic pressure is not output from any of the shift valves 63 to 65, the other friction engagement elements are released.

(3) First to third in the D range second speed
All the solenoid valves 66 to 66 are turned on.

In this case, the forward clutch 31 is engaged as in the case of the first speed in the D range. Further, the oil pressure in the first output line 111 is sequentially changed by the 1-2 shift valve 6
3 and the servo apply line 121 to the apply port 35b of the 2-4 brake 35. At this time, since the hydraulic pressure is not supplied to the release chamber 38c, 2-4
The brake 35 is engaged. The other frictional fastening elements are released as no hydraulic pressure is supplied.

(4) In the D range third speed, the first solenoid valve 66 is turned on and the second and third solenoid valves 67, 68 are turned off.

In this case, similarly to the case of the second speed in the D range,
The forward clutch 31 is engaged and the engagement chamber 38b
Is supplied with hydraulic pressure. However, as described later, since the hydraulic pressure is also supplied to the release chamber 38c, the 2-4 brake 35 is released.

Then, the oil pressure in the first output line 111 is sequentially supplied to the coast clutch 32 via the 3-4 shift valve 65 and the coast clutch line 123, and the coast clutch 32 is engaged. Also, the second
The hydraulic pressure in the output line 112 becomes 3- through the 2-3 shift valve 64 and the 3-4 clutch line 124 in order.
It is supplied to the 4-clutch 33, and the 3-4 clutch 33 is engaged. Further, the hydraulic pressure in the 3-4 clutch line 124 is changed in order from the line 126 and the 3-4 shift valve 6
5 and the servo release line 127, and is supplied to the release chamber 38c of the 2-4 brake 35.
-4 The brake 35 is released. The reverse clutch 34 and the low reverse brake 36 are released because hydraulic pressure is not supplied.

(5) In the D range fourth speed, the first and third solenoid valves 66 and 68 are turned on, and the second solenoid valve 67 is turned off.

In this case, as in the case of the second speed in the D range,
The forward clutch 31 and the 2-4 brake 35 are engaged. Further, similarly to the case of the third speed in the D range, the 3-4 clutch 33 is engaged. The other frictional fastening elements are released as no hydraulic pressure is supplied.

(6) In the S range first speed, the manual valve 62 takes the S range position, but the hydraulic pressure supply path to the friction engagement element is the same as in the D range first speed.

(7) In the S range second speed, the first and second solenoid valves 66 and 67 are turned on and the third solenoid valve 68 is turned off.

In this case, as in the case of the second speed in the D range,
The forward clutch 31 and the 2-4 brake 35 are engaged. Further, the coast clutch 32 is engaged as in the case of the D range third speed. The other frictional fastening elements are released as no hydraulic pressure is supplied.

(8) In the case of S range 3rd speed, D range 3
It is similar to the case of speed.

(9) In the case of the first speed in the L range, the manual valve 31 is in the L range position, the first and third output lines 111 and 113 communicate with the main line 110, and hydraulic pressure is applied to the both output lines 111 and 113. Is supplied. First
And the third solenoid valves 66, 68 are turned off, and the second solenoid valves 66, 68 are turned off.
The solenoid valve 67 is turned on.

In this case, the forward clutch 31 is engaged in the same manner as in the first speed in the D range, and the coast clutch 32 is engaged in the same manner as in the third speed in the D range. Further, the hydraulic pressure in the third output line 113 is sequentially supplied to the low reverse brake 36 via the low reducing valve 80, the line 128, the 1-2 shift valve 63, and the low reverse brake line 129, The low reverse brake 36 is engaged. The other frictional fastening elements are released as no hydraulic pressure is supplied.

(10) In the L range second speed, the manual valve 62 takes the L range position, but the hydraulic pressure supply path to the friction engagement element is the same as in the S range second speed.

Further, the shift control method according to the embodiment of the present invention uses the shift control by the control 200 described above when the shift is performed from the third speed to the first speed.
-4 It is applied to the switching control of the brake 35. The shift control method will be described below with reference to FIGS. 8 and 9. FIG. 8 is a flowchart of the switching control of the first to third solenoid valves 66 to 68 at the time of shifting from the third speed shift stage to the first speed shift stage, and FIG. 2-4 when shifting to high speed
The operating state of the hydraulic actuator 38 of the brake 35, the ON-OFF switching of the first to third solenoid valves 66 to 68, and the changing state of the hydraulic pressure in the chambers 38b and 38c of the 2-4 brake 35 are shown. In addition, in FIG.
The change state of the hydraulic pressure in the engagement chamber 38b of the brake 35 is a broken line B, and the change state of the hydraulic pressure in the release chamber 38c is a one-dot chain line C.
The change state of the hydraulic pressure of the 3-4 clutch 33 is indicated by the solid line A.

During the third speed, the first solenoid valve 66 is turned on and the second and third solenoid valves 67,
Both 68 are turned off, and pressure oil is supplied to the fastening chamber 38b and the release chamber 38c of the 2-4 brake 35, respectively. At this time, the 2-4 brake 35 has a spring 38d.
Due to the urging force of the piston 38a, the piston 38a is closer to the release chamber 38c, and is in the released state (state of FIG. 9A-1).

When shifting from such a 3rd speed shift stage to a 1st speed shift stage, it is performed according to the flow chart shown in FIG. That is, after the start, first, after confirming that the accelerator switch 206 is not ON, that is, what is called kickdown (step S1), it becomes 1 at the time of shifting from the third gear to the first gear 3-1. When the current value F (t) of the shift flag is 1 and the previous value F (t−Δt) is 0, that is, immediately after the shift command is output, all the first to third solenoid valves 66 to 68 are It is turned on (steps S2 to S4). This state is the second
This is the same as in the shift stage, and the pressure oil is removed from the release chamber 38c while the pressure oil is being supplied to the engagement chamber 38b of the 2-4 brake 35. At this time, the piston 3 of the 2-4 brake 35
8a receives the pressing force of the pressure oil in the fastening chamber 38b and moves to the release chamber 38c side, and the pressure oil in the release chamber 38c is forcibly removed with this movement (Fig. 9 (a-2)). Status).
This state is the time (T
It continues until (M / Δt) elapses (step S5-
S7).

When the above time (TM / Δt) has elapsed, the first solenoid valve 66 is turned off, and the second and third solenoid valves 67 and 68 are both turned on (step S8).
) 2-4 Brake 35 fastening chamber 38b and release chamber 3
The pressure oil is removed from each of 8c. At this time, the piston 38a of the 2-4 brake 35 is moved from the release chamber 38c side to the fastening chamber 38b side by the urging force of the spring 38d, and the pressure oil in the fastening chamber 38b is forcibly removed with this movement ( 9 (a-3) state). Further, there is almost no oil left in the release chamber 38c.

When shifting from the 1st speed shift stage to the 2nd speed shift stage in such a state, pressure oil is supplied only to the engagement chamber 38b of the 2-4 brake 35, and the piston 38a is moved to the release chamber 38c side. It moves and becomes a fastening state. At this time, since almost no oil remains in the release chamber 38c, the residual pressure hardly occurs in the release chamber 38c due to the movement of the piston 38a. As a result, the movement of the piston 38a and the switching of the 2-4 brake 35 can be smoothly performed, and the occurrence of shift shock due to the delay of the switching timing can be prevented.

[0077]

As described above, according to the shift control method for the automatic transmission of the present invention, the pressure oil is removed from both the engagement chamber and the release chamber from the gear stage where the pressure oil is supplied to the release chamber of the friction engagement element. When shifting to another gear, the gear is shifted through a state in which pressure oil is supplied to the engagement chamber and positively removes the pressure oil in the release chamber. It is possible to prevent the residual pressure from being generated in the release chamber when shifting to the supplied gear, and it is possible to reduce the shift shock.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram showing a vicinity of a transmission main body in a hydraulic control circuit of the automatic transmission.

FIG. 3 is a hydraulic circuit diagram showing the vicinity of the regulator valve.

FIG. 4 is a hydraulic circuit diagram showing the vicinity of the manual valve.

FIG. 5 is a hydraulic circuit diagram similarly showing the vicinity of the 3-4 shift valve.

FIG. 6 is a hydraulic circuit diagram showing the vicinity of the lockup shift valve.

FIG. 7 is a block diagram of a solenoid valve control system.

FIG. 8 is a flowchart of switching control of the first to third solenoid valves when shifting from the third gear to the first gear.

FIG. 9 is an operating state of hydraulic actuators of the 2-4 brake when shifting from the 3rd gear to the 2nd gear through the 1st gear, and ON-OFF of the first to third solenoid valves.
It is a figure which shows change and the change state of the hydraulic pressure of each room etc. of said 2-4 brake.

FIG. 10 is a view corresponding to FIG. 9 showing a conventional example. However, the first
~ The change state of ON-OFF switching of the third solenoid valve is omitted.

[Explanation of symbols]

 35 2-4 Brake (Friction Fastening Element) 38a Piston 38b Fastening Chamber 38c Release Chamber

Front page continuation (72) Inventor Hiroshi Shinozuka No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Ltd. (72) Inventor Baba No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Ltd. (72 ) Inventor Kenji Okamoto 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (1)

[Claims] 1. A friction fastening element having a fastening chamber and a release chamber provided in front of and behind a piston, the friction fastening element being fastened when pressure oil is supplied only to the fastening chamber, and the fastening chamber and In an automatic transmission configured to release engagement when pressure oil is supplied to both release chambers or when pressure oil is removed from both chambers, pressure oil is supplied to the release chamber of the friction engagement element. When shifting from a shift stage to a shift stage in which pressure oil is removed from both chambers,
A shift control method for an automatic transmission, characterized in that a shift is performed through a state in which pressure oil is supplied to a fastening chamber and pressure oil in a release chamber is positively removed.