JP3455978B2 - Transmission control device for automatic transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission mounted on a motor vehicle, and more particularly to an improvement of two friction engagement elements having different torque transmission capacities that are engaged together at a predetermined speed. Involve

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted in an automobile has a combination of a torque converter and a speed change mechanism and a power transmission path of the speed change mechanism, as disclosed in JP-A-63-186055. It is configured to be switched by a selective operation of a plurality of friction engagement elements such as clutches and brakes, and to automatically shift to a predetermined gear stage,
This type of automatic transmission is provided with a hydraulic control circuit that controls the supply and discharge of hydraulic pressure to and from the actuators of the friction engagement elements. In the hydraulic control circuit, for example, a regulator valve that adjusts the discharge pressure of the oil pump to a predetermined line pressure, a manual valve that switches the range by manual operation, and an oil passage that operates according to the shift speed and communicates with the actuator are switched. Thereby, a plurality of shift valves or the like that selectively actuate the plurality of friction engagement elements are provided.

By the way, the capacities of friction engagement elements such as clutches and brakes are determined according to the magnitude of the transmission torque in the power transmission path of the speed change mechanism. For this reason,
Two friction engagement elements having different torque transmission capacities may be engaged together at a predetermined shift speed. For example, in the first speed stage where the engine brake can act, a low reverse brake having a large torque transmission capacity and a coast clutch having a small torque transmission capacity are engaged. In this case, in the hydraulic control circuit, a frictional engagement element having a small torque transmission capacity (for example, a coast clutch) is first engaged, and then a frictional engagement element having a large torque transmission capacity (for example, a low reverse brake) is engaged to shift down the gear. It is common practice to control to complete the. This is because the frictional fastening element with a small torque transmission capacity is later fastened and shifted.
This is because if the downshift is completed, the frictional engagement element is likely to slip at the time of engagement, and the shift may not be smoothly performed.

[0004]

However, at a low vehicle speed where the engine output is small and the transmission torque is small accordingly, a gear shift shock is generated when the frictional engagement element having a large torque transmission capacity is engaged later to complete the downshift. However, there is a problem in that it causes a great deal of damage and impairs the riding comfort.

The present invention has been made in view of the above points, and an object thereof is to correlate with the transmission torque when two friction engagement elements having different torque transmission capacities are fastened together at a predetermined shift speed. Depending on the size of the vehicle speed, by appropriately changing the fastening order of both friction fastening elements,
An object of the present invention is to provide a gear shift control device for an automatic transmission, which can reduce gear shift shock at low vehicle speed while preventing gear slippage of a frictional engagement element and reliably performing gear shift.

[0006]

In order to achieve the above object, the invention according to claim 1 includes a first frictional engagement element having a large torque transmission capacity and a second frictional engagement element having a small torque transmission capacity. And an automatic transmission in which both of the friction engagement elements are fastened together at a predetermined shift speed, a vehicle speed detecting means for detecting a vehicle speed of an automobile equipped with the automatic transmission, and a signal from the vehicle speed detecting means. At high vehicle speed, the first
Of the second friction engagement element is completed after the second friction engagement element is completed to complete the downshift to the predetermined gear stage, and the second friction engagement element is connected to the first friction engagement element at a low vehicle speed. And a shift-down shift control means for controlling the shift-down shift to complete the shift-down shift to the predetermined shift stage .

The invention according to claim 2 is dependent on the invention according to claim 1, and shows one specific embodiment thereof. That is,
The first friction engagement element is a low reverse brake, the second friction engagement element is a coast clutch, and the low reverse brake and the coast clutch are both in the first speed stage in which engine braking can be applied. It will be concluded.

The invention according to claim 3 is dependent on the invention according to claim 2 or 3, and is one of the components of the shifter.
The downshift control means is specifically shown. That is, the shift control means is configured to perform the engagement control by the first and second friction engagement elements by switching the shift valve provided in the hydraulic circuit.

[0009]

With the above construction, in the invention according to claim 1,
When two friction engagement elements having different torque transmission capacities are engaged together to perform a gear shift, both friction engagements are controlled under the control of the gear shift control means in accordance with the vehicle speed correlated with the transmission torque in the power transmission path of the speed change mechanism. The fastening order of the elements is changed. That is, at a low vehicle speed where the engine output is small and the transmission torque of the speed change mechanism is small, the first frictional engagement element having a large torque transmission capacity is engaged first, and then the second frictional engagement element having a small torque transmission capacity is engaged. Predetermined gear
Complete the downshift. At the time of completion of the shift by the engagement of the second frictional engagement element, the torque transmission capacity of the second frictional engagement element is small, so that a large shift shock does not occur.

On the other hand, at the time of high vehicle speed in which the engine output is large and the transmission torque of the speed change mechanism is large, the second frictional engagement element having a small torque transmission capacity is engaged first, and then the first frictional engagement element having a large torque transmission capacity. Conclude the above prescribed
To complete the downshift. This first
Since the torque transmission capacity of the first frictional engagement element is large at the time of completion of gear shifting by the engagement of the frictional engagement element, the frictional engagement element does not slip.

[0011]

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 a vehicle according to an embodiment of the present invention. The automatic transmission AT has a torque of an engine output shaft 1 (engine torque) as a main component. ) Is transmitted to the turbine shaft 2 and the torque of the turbine shaft 2 is further changed, and when the reverse gear is selected, the rotation is reversed to output from the output gear 4 to the drive wheel side. And a transmission gear mechanism 5 that operates. 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 pump shaft 6 allows the pump shaft 6 to be located behind the transmission gear mechanism 5 (left side in FIG. 1). The oil pump 7 arranged in () is rotationally driven.

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. Incidentally, 17 is a lock-up clutch for directly connecting the engine output shaft 1 and the turbine shaft 2 as required.

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 to 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 switch the gear ratio or the rotational direction of the output gear 4, clutches and brakes are provided as a plurality of friction engagement elements. 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.

Here, the torque transmission capacities of the various clutches 31 to 34 and the brakes 35 and 36 are determined by their locations in the torque transmission path in the speed change gear mechanism 5, but in the case of this embodiment. The low reverse brake 36 has the largest torque transmission capacity, and the coast clutch 32 has the smallest torque transmission capacity. Therefore, the low reverse brake 36 corresponds to the first frictional engagement element described in claim 1, and the coast clutch 32 corresponds to the second frictional engagement element described in claim 1. In the following description, various clutches 31 to 3 will be used.
4 and the brakes 35 and 36 are appropriately collectively referred to as "friction engaging elements".

By changing the engagement / release patterns of the friction engagement 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.

[0018]

[Table 1]

(1) In the case of 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 second range of the D range, 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. 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 unit.
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 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 second speed of 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 characteristics are basically the same as those in the first speed in 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 35 of the 2-4 brake 35
a is a servo piston having an apply port 35b and a release port 35c.
The 2-4 brake 35 is engaged when the hydraulic pressure is supplied only to 5b, and is released when the hydraulic pressure is supplied to both ports 35b and 35c or both hydraulic pressures are released. The actuators of the other frictional engagement elements 31 to 34, 36 are composed of ordinary hydraulic pistons, which engage the frictional engagement element when the hydraulic pressure is supplied and release the frictional engagement element when the hydraulic pressure is 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 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 to the apply port 35b of the servo piston 35a via the one-way orifice 73 and the exhaust pressure control valve 74. Therefore, when the first solenoid valve 66 is on in the D, S, and L ranges, the hydraulic pressure (servo apply pressure) is introduced into the apply port 35b. 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 exhaust pressure control valve 74
The hydraulic oil is quickly discharged when the discharge of the servo apply pressure is started, and the hydraulic oil is gently discharged when the servo apply pressure drops to a predetermined pressure. It should be noted that the above-mentioned Appla Import 35b is connected to the line 2-4 via the line 122.
An accumulator 75 for buffering when the brake is applied is connected.

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.
8 is off and the spool of the shift valve 65 is located on the left side, the release port 35 of the servo piston 35a.
It communicates with the servo release line 127 leading to c. Therefore, in the D and S ranges, the second and third solenoid valves 6
When both 7 and 68 are off, the servo release pressure is introduced into the release port 35c of the servo piston 35a, and 2
-4 The 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 the 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 lock-up shift valve 85 for operating the lock-up clutch 17 in the torque converter 3, and the lock-up 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. 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 modulator for generating a throttle modulator pressure according to the engine load by operating a 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-described structure, 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 during gear 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 apply port 35b of the servo piston 35a 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 145 is shut off and the one-way orifice 73
The operating oil is slowly supplied to the apply port 35b of the servo piston 35a. The pilot pressure introduced into the pilot chamber 95a of the timing valve 95 is also introduced into the pilot chamber 80a at one end of the low reducing valve 80 (see FIG. 6) via 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 engagement of the low reverse brake 36 is 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 vehicle speed sensor 201 as vehicle speed detecting means for detecting the vehicle speed of an automobile equipped with the automatic transmission AT.
From the throttle opening sensor 202 for detecting the throttle opening of the engine, and a shift position sensor for detecting the position (range) of a shift lever (not shown) provided in the automatic transmission AT. A signal from 203, a signal from a turbine speed sensor 204 that detects the turbine speed of the torque converter 3, and a signal from an oil temperature sensor 205 that detects the temperature of the hydraulic oil are input. . Then, the control 200
Controls ON / OFF of the shift solenoid valves 66 to 68 based on a map preset for each range selected by the shift lever according to the vehicle speed of the vehicle and the throttle opening of the engine. . 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.

[0057]

[Table 2]

Next, referring to Table 2, the hydraulic pressure supply path in the hydraulic pressure control circuit 60 in each traveling range (R, D, S, L range) or shift speed 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 case of the second speed in the D range
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 hydraulic pressure is not supplied to the release port 35c, the 2-4 brake 35 is engaged. The other frictional fastening elements are released as no hydraulic pressure is supplied.

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

In this case, as in the case of the D range second speed,
The forward clutch 31 is engaged and hydraulic pressure is supplied to the apply port 35b. However, as will be described later, since the hydraulic pressure is also supplied to the release port 35c, the 2-4 brake 35 is released.

The hydraulic 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 are supplied to the release port 35c of the 2-4 brake 35, and the 2-4 brake 35 is released as described above. The reverse clutch 34 and the low reverse brake 36 are released because hydraulic pressure is not supplied.

(5) In the fourth range of the D range, 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 D range second speed,
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 L range first speed, 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 the 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 as in the first speed in the D range, and the coast clutch 32 is engaged 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.

Here, the torque transmission capacity of each of the friction engagement elements is determined by the torque transmission path in the transmission gear mechanism 5 as follows:
In the case of the present embodiment, the torque transmission capacity of the low reverse brake 36 is set to be the largest and the torque transmission capacity of the coast clutch 32 is set to be the smallest, although the torque transmission capacity is determined by the positions of the arrangement. Therefore, corresponds to the first frictional engagement element to the low reverse brake 36 is defined in claim 1, the coast clutch 32 is according to claim 1 2
It corresponds to the frictional fastening element of.

The low reverse brake 36 and the coast clutch 32 are engaged together.
When the low reverse brake 36 is always engaged later when shifting from the L range 2nd speed to the L range 1st speed, the shift shock due to the engagement of the low reverse brake 36 is large at a low vehicle speed with a small transmission torque. Occurs. Therefore, as a feature of the present invention, the controller 200 (see FIG. 7) for controlling various solenoid valves is in accordance with the flowchart shown in FIG. 8 according to the vehicle speed during the shift from the L range second speed to the L range first speed. The engagement order of the coast clutch 32 and the low reverse brake 36 is changed. Also, FIG. 9 and FIG.
Is an ON / OFF combination pattern of the shift solenoid valves 66 to 68 and the bypass control solenoid valve 96 and the operation of each friction engagement element (actuator) during the shift from the L range second speed to the L range first speed. It is a figure which shows the relationship with a pressure, FIG. 9 shows the time of a gear shift at a high vehicle speed, and FIG. 10 shows the time of a gear shift at a low vehicle speed. 9 and 10, A is a characteristic curve for changing the operating pressure of the forward clutch 31 (forward clutch pressure), B is a characteristic curve for changing the operating pressure of the coast clutch 32 (coast clutch pressure), and C is shown.
2 is a change characteristic line of the operating pressure (servo apply pressure) of the apply port 35b of the 2-4 brake 35, and D is a change characteristic line of the operating pressure of the low reverse brake 36.

Next, with reference to FIGS. 8 to 10, the order of engagement of the friction engagement elements at the time of shifting from the L range second speed to the L range first speed will be described.

In the case of the second speed in the L range, as described in detail in Table 1 above, the forward clutch 31 and the coast clutch 3
The 2 and 2-4 brakes 35 are engaged and the low reverse brake 36 is released. In addition, as described in detail in Table 2 above, the first and second solenoid valves 66, 6 for shifting are changed.
7 is turned on, and the third solenoid valve 78 for shifting is turned off. The bypass control solenoid valve 96
Is turned on only during a shift and is turned off at each shift stage.

Then, in the flow chart shown in FIG. 8, after starting from such a state, counters T1 and T2 for measuring the elapsed time from the shift start time are cleared to zero in step S1, and step S2 The signals from the various sensors 201 to 205 are read with. Then, in step S3, it is determined whether or not to shift down from the second speed in the L range to the first speed based on the turbine speed, engine load, etc., and if downshifting is required, in step S4 the vehicle speed is lower than the predetermined value V1. Determine if it is small.

When the determination in step S4 is NO, that is, when the vehicle speed is higher than the predetermined value V, the first solenoid valve 66 for shifting is turned off and the second solenoid valve 67 for shifting is turned on in step S5. Is turned on, the third solenoid valve 68 for speed change is turned off, and the solenoid valve 96 for bypass control is turned on. As a result, as shown by the change characteristic line C in FIG.
5 is released.

Subsequently, the counter T2 is incremented by 1 in step S6, and then in step S7, it is waited for the counter T2 to become larger than the predetermined value α. This predetermined value α corresponds to approximately half the time required for shifting. And
When the counter T2 becomes larger than the predetermined value α, the first solenoid valve 66 for shifting is turned off, the second solenoid valve 67 for shifting is turned on in step S13, the third solenoid valve 68 for shifting, and the bypass control. Both solenoid valves 96 are turned off. As a result, as shown by the change characteristic line D in FIG. 9, the low reverse brake pressure increases and the low reverse brake 36 is engaged,
The shift to the first speed in the L range is completed. Here, since the engagement operation of the low reverse brake 36 is performed after the release operation of the 2-4 brake 35, both brakes 35, 36 are
Therefore, the occurrence of the double lock state is prevented.
The forward clutch 31 and the coast clutch 32
Are maintained in the engaged state without changing their operating pressure.

On the other hand, when the determination in step S4 is YES, that is, when the vehicle speed is lower than the predetermined value V, the first solenoid valve 66 for shifting is turned off in step S8, and the second and third shifting valves are used. Solenoid valves 67,6
8 and the bypass control solenoid valve 96 are both turned on. As a result, as shown by the change characteristic line C in FIG. 10, the servo apply pressure of the 2-4 brake 35 decreases and the brake 35 is released. Further, as indicated by a change characteristic line B in FIG. 10, the coast clutch pressure is reduced and the coast clutch 32 is released.

Subsequently, the counter T1 is incremented by 1 in step S9, and then in step S10, it is waited until the counter T1 becomes larger than the predetermined value a. The predetermined value a corresponds to approximately one fourth of the time required for shifting. When the counter T1 becomes larger than the predetermined value a,
In step S11, the first solenoid valve 66 for shifting is turned off, the second and third solenoid valves 67 for shifting,
Both 68 are turned on, and the bypass control solenoid valve 96 is turned off. As a result, as shown by the change characteristic line D in FIG. 10, the low reverse brake pressure increases and the low reverse brake 36 is engaged. Since the engagement operation of the low reverse brake 36 is performed after the release operation of the 2-4 brake 35, the occurrence of the double lock state of both brakes 35 and 36 is prevented.

Subsequently, in step S12, the process waits until the counter T1 becomes larger than the predetermined value b. This predetermined value b corresponds to approximately half the time required for shifting. When the counter T1 becomes larger than the predetermined value b, step S13
The first solenoid valve 66 for shifting is turned off, the second solenoid valve 67 for shifting is turned on, and the third solenoid valve 68 for shifting and the bypass control solenoid valve 96 are both turned off. As a result, as shown by the change characteristic line B in FIG. 10, the coast clutch pressure rises, the coast clutch 32 is engaged, and the shift to the L range first speed is completed. The forward clutch 31 is maintained in the engaged state without changing its operating pressure.

As described above, when shifting (downshifting) from the 2nd speed to the 1st speed in the L range is performed at a high vehicle speed in which the transmission torque in the speed change gear mechanism 5 is large, the low reverse brake 36 having a large torque transmission capacity is provided. Since the gear is fastened later to complete the shift, the slip does not occur during the engagement of the low reverse brake 36, and the shift can be smoothly and reliably performed. On the other hand, when the gear shift is performed at a low vehicle speed where the transmission torque in the transmission gear mechanism 5 is small, the coast clutch 32 having a small torque transmission capacity is engaged after the low reverse brake 36 to complete the gear shift. Shock can be suppressed.

Moreover, the above-mentioned shift control is performed by the automatic transmission A.
ON / OFF control of the existing shift solenoid valve 96 in the hydraulic control circuit 60 of T, and by extension, the shift valve 63
Since it is exhibited by switching between .about.65 and no new valve or the like is required, it is possible to implement while simplifying the configuration.

The present invention is not limited to the above embodiments, but includes various other modifications.
For example, in the above embodiment, the downshift from the 2nd speed of the L range to the 1st speed was described, but when the 2nd speed of the D range is changed to the L range by the shift lever, the speed is changed to the 1st speed of the L range. When the vehicle is running, the engagement order of the coast clutch 32 and the low reverse brake 36 may be changed according to the vehicle speed.

In the above embodiment, the present invention is applied to the case where the two friction engaging elements having different torque transmission capacities are the coast clutch 32 and the low reverse brake 36. However, depending on the type of automatic transmission, The frictional engagement elements other than the above have different torque transmission capacities and may be simultaneously engaged, and the present invention can be applied to such a case as well.

[0091]

As described above, according to the shift control device for an automatic transmission of the present invention, in the case where two friction engaging elements having different torque transmission capacities are fastened together at a predetermined shift speed to shift gears, Depending on the vehicle speed that correlates with the transmission torque of the above, the engagement order of the both friction engagement elements is changed, and at low vehicle speeds, the friction engagement elements with a small torque transmission capacity are engaged later to shift down to the predetermined gear position. Completed,
When the vehicle speed is high, the frictional engagement element having a large torque transmission capacity is engaged later to complete the shift-down shift to the predetermined gear, so that the reduction of the shift shock at the low vehicle speed and the friction at the high vehicle speed. The fastening slippage of the fastening element can be prevented together.

In particular, in the invention according to claim 3, the change control of the engagement order is exerted by switching the existing shift valve, so that there is also an effect that the structure of the device itself can be simplified.

[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 flow chart diagram showing on / off control of a solenoid valve at the time of shifting from the second speed to the first speed in the L range.

FIG. 9 is a diagram showing a relationship between an ON / OFF combination pattern of each solenoid valve for shifting and an operating pressure of each friction engagement element during shifting from the 2nd speed to the 1st speed in the L range at a high vehicle speed. is there.

FIG. 10 is a diagram showing a relationship between an on / off combination pattern of each solenoid valve for shifting and an operating pressure of each friction engagement element during shifting from the 2nd speed to the 1st speed in the L range at a low vehicle speed. is there.

[Explanation of symbols]

32 coast clutch (second friction engagement element) 36 Low reverse brake (first friction engagement element) 63 1-2 shift valve 64 2-3 shift valve 65 3-4 Shift valve 200 controller (shift control means) 201 Vehicle speed sensor (vehicle body detection means)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-256352 (JP, A) JP-A-4-113065 (JP, A) JP-A-4-248064 (JP, A) JP-A-3- 292447 (JP, A) JP-A-3-56756 (JP, A) JP-A-2-42257 (JP, A) JP-A-2-261958 (JP, A) JP-A-63-186055 (JP, A) JP-A-62-266256 (JP, A) JP-A-58-77959 (JP, A) Actual Kaihei 2-4057 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (3)

(57) [Claims] Claim: What is claimed is: 1. An automatic automatic clutch comprising a first frictional engagement element having a large torque transmission capacity and a second frictional engagement element having a small torque transmission capacity, wherein both of the frictional engagement elements are engaged together at a predetermined shift speed. In a transmission, a vehicle speed detecting means for detecting a vehicle speed of an automobile equipped with the automatic transmission, and a signal from the vehicle speed detecting means, and when the vehicle speed is high, the first friction engaging element is connected to the second friction engaging element. The second frictional engagement element is engaged with the first frictional engagement element at a low vehicle speed by engaging later to complete the downshifting to the predetermined gear .
Signed in later than the frictional engagement element to the predetermined shift stage
And a shift-down shift control means for controlling the shift-down shift to be completed. 2. The first friction engagement element is a low reverse brake, the second friction engagement element is a coast clutch, and the low reverse brake and the coast clutch are first speed shifts in which engine braking can be applied. The gear shift control device for an automatic transmission according to claim 1, wherein both gears are fastened together. 3. The shift-down shift control means switches the first valve by switching a shift valve provided in a hydraulic circuit.
The shift control device for an automatic transmission according to claim 1 or 2, wherein the shift control device is provided so as to control engagement of the second friction engagement element.