JPH0617918A - Speed change control unit of automatic transmission - Google Patents

Abstract

PURPOSE:To realize a shift that does not cause the shock of engagement by controlling the shift so that when a shiftup is made through lowering of engine load the initial period of time during which engagement hydraulic pressure supplied to frictional engaging parts is increased is made longer than when the shiftup is made through an increase in vehicle speed. CONSTITUTION:A transmission gear mechanism 30, to which engine power is inputted via a torque convertor 20, includes frictional engaging parts 41-46, such as clutches and brakes, and one-way clutches 51, 52, and makes a shift and outputs the power by switching of their states of engagement. Switching of the transmission gear ratio is achieved by a hydraulic control circuit, and hydraulic pressure for engaging a predetermined frictional engaging part is supplied in a state of intermediate pressure using an accumulator. In this case, at the initial stage of transmission when the predetermined engaging part is engaged, a flow rate control means is controlled so that the amount of flow of hydraulic fluid is increased for a predetermined period of time, and when a shiftup is made through lowering of engine load, the period of time during which the amount of flow of the hydraulic fluid is increased is made longer than when the shiftup is achieved through an increase in vehicle speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear shift control device for an automatic transmission, and more particularly to a gear shift control device for supplying a hydraulic pressure for frictional engagement to a frictional engagement element in a rack pressure state using an accumulator.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile is a combination of a torque converter and a speed change gear mechanism.
The power transmission path of the speed change gear mechanism is switched by the selective operation of a plurality of friction engagement elements such as clutches and brakes to automatically change gears to a predetermined gear stage. 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. This hydraulic control circuit, specifically,
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 operating state and leads to each of the above actuators. It is composed of a plurality of shift valves that selectively actuate the engagement elements and various valves that perform other auxiliary actions. In recent years, in particular, by driving the shift valves with solenoid valves, shift control can be performed. In some cases, it may be performed with higher accuracy by adapting to the operating conditions.

By the way, in this type of automatic transmission, when the engaging hydraulic pressure during shifting is set to an intermediate pressure state called a so-called shelf pressure in order to reduce shock when the frictional engaging elements in the released state are engaged. However, in general, an accumulator and an orifice are installed in a hydraulic pressure supply passage that supplies the hydraulic pressure to the friction engagement element, and the hydraulic oil that has passed through the orifice is introduced into the accumulator to form a predetermined shelf pressure. It is like this.

However, when the hydraulic pressure for engagement is supplied to the frictional engagement element in a state where the flow rate is reduced by the orifice as described above, there is a problem that the time lag in the initial stage of the gear shifting operation becomes large. As disclosed in Japanese Patent Laid-Open No. 2-76968, a bypass passage that bypasses the orifice and a valve that opens and closes the bypass passage may be provided. According to this, by opening the bypass passage for a predetermined period at the time of gear shifting, the flow rate of the hydraulic oil is increased, the time lag at the beginning of the gear shifting operation is reduced, and in the latter half of the gear shifting operation, the orifice and accumulator are used. Since the hydraulic pressure will rise in the shelf pressure state, shock will be reduced.

[0005]

By the way, in this type of automatic transmission, a shift pattern is set in advance using, for example, vehicle speed and throttle opening as parameters, and
When the actual driving state (vehicle speed and throttle opening) passes through the shift line that constitutes the shift pattern, shift control is performed to downshift or upshift the shift stage. There are so-called schedule-up shifts that are performed as the vehicle speed increases and so-called back-out shifts that are performed as the engine load decreases. In that case, conventionally, since the pressure characteristic is set so that the shelf pressure is formed corresponding to the engine load, the following problem may occur.

That is, taking 1-2 shifts as an example, as shown in FIG. 10, a 1-2 shift in which the operating state indicated by the vehicle speed and the throttle opening constitutes a shift pattern by an increase in the vehicle speed, for example. When the P ₁ point changes to the R ₂ point across the upline L ₁₂ , the schedule up shift is performed. On the other hand, so that the backout shift is performed when the operating state by a reduction of the throttle opening is changed to R ₄ points across the 1-2 upshift line L ₁₂ from _three points P.

In this case, the gear ratio decreases in the vehicle stop speed range in the former schedule upshift, so that FIG.
As indicated by the solid line, the turbine speed of the torque converter input to the transmission gear mechanism of the automatic transmission also changes relatively small. On the other hand, in the latter back-out shift, the gear ratio decreases in the high vehicle speed range, so that the turbine speed fluctuates relatively more than the schedule-up shift as shown by the broken line in the figure. In that case, since the operating characteristic of the accumulator is generally a fixed characteristic, the shelf pressure state is set to be long in order to satisfy both the schedule up shift and the back out shift. In the back-out shift, the shift operation is completed in the latter half of the shelf pressure. Therefore, during the backout shift, the frictional engagement element unnecessarily slips in the first half of the shelf pressure obtained by the accumulator, and the frictional element is engaged through a relatively long slip state as compared with the schedule up shift. As a result, it causes a problem in terms of durability.

To solve this problem, it is conceivable to set the shelf pressure level to a large value, but if this is the case, the engagement shock will increase during normal schedule-up shifting, which is not preferable.

The present invention addresses the above problems in an automatic transmission in which a hydraulic pressure for engagement with a predetermined frictional engagement element is supplied in a shelf pressure state by using an accumulator at the time of gear shifting, and the frictional engagement element is involved. It is an object of the present invention to allow the shift operation to be favorably performed during the shift-up shift.

[0010]

That is, a shift control device for an automatic transmission according to an invention (hereinafter referred to as a first invention) according to claim 1 of the present application includes a plurality of frictions for switching power transmission paths of a shift gear mechanism. A fastening element and a hydraulic control circuit that controls the supply and discharge of the working hydraulic pressure to and from the hydraulic actuators of these friction fastening elements, and a hydraulic supply passage that supplies the working hydraulic pressure to a predetermined friction fastening element in this hydraulic control circuit, In an automatic transmission provided with an accumulator that stores hydraulic oil and a flow rate adjusting unit that is arranged on the upstream side of the accumulator and that adjusts the flow rate of hydraulic oil, a predetermined speed is established at the initial stage of shifting when the predetermined frictional engagement element is engaged. Control means for operating the flow rate adjusting means so as to increase the flow rate of the hydraulic oil during the period, and the increase period during the shift-up shift due to the reduction of the engine load. Characterized in that the provided and increasing period changing means for longer than the time of shift-up due to an increase in vehicle speed.

The invention according to claim 2 of the present application (hereinafter,
A shift control device for an automatic transmission according to a second invention),
A plurality of friction engagement elements that switch the power transmission paths of the speed change gear mechanism, and a hydraulic control circuit that controls supply and discharge of operating hydraulic pressure to and from hydraulic actuators of these friction engagement elements are provided. An accumulator for storing hydraulic oil, a throttle element arranged upstream of the accumulator, a bypass passage for bypassing the throttle element, and an opening / closing for opening and closing the bypass passage in a hydraulic pressure supply passage for supplying the operating hydraulic pressure to the element. And a control means for operating the opening / closing means so as to open the bypass passage for a predetermined period at the initial stage of gear shifting when the predetermined friction engagement element is engaged, and a shift due to a reduction in engine load. Opening period when opening the bypass passage during upshifting longer than during upshifting due to an increase in vehicle speed Characterized by providing and changing means.

The shift control device for an automatic transmission according to the invention of claim 3 of the present application (hereinafter referred to as the third invention) includes a plurality of friction engagement elements for switching the power transmission paths of the transmission gear mechanism, and these friction engagement elements. A hydraulic control circuit for controlling supply and discharge of operating hydraulic pressure to and from a hydraulic actuator of the friction engagement element, and an accumulator for storing operating oil in a hydraulic supply passage for supplying the operating hydraulic pressure to a predetermined friction engagement element in the hydraulic control circuit. And an input speed detecting means for detecting an input speed of the speed change gear mechanism, and the predetermined friction in an automatic transmission provided with a flow rate adjusting means arranged upstream of the accumulator for adjusting a flow rate of hydraulic oil. Control means for actuating the flow rate adjusting means so that the flow rate of the hydraulic oil increases for a predetermined period at the initial stage of gear shifting when the engagement element is engaged;
An increase period during a shift-up shift due to a decrease in engine load, which is made longer than that during a shift-up shift due to an increase in vehicle speed, and which is increased as the input speed at the start of the shift-up shift increases. And a changing means.

[0013]

According to the above construction, the following operation can be obtained.

That is, in any of the first to third inventions, the initial increase of the engagement hydraulic pressure supplied to the friction engagement element is performed during the shift up due to the decrease of the engine load than during the shift up shift due to the increase of the vehicle speed. Since the time becomes longer, the amount of hydraulic oil flowing into the accumulator increases correspondingly, and the shelf pressure supplied to the friction engagement element increases. Therefore, if this increase period is appropriately set, the shelf pressure corresponding to the transmission torque is formed at any shift-up shift,
The fastening operation of the friction element is performed well, and the durability is improved.

In particular, in the third aspect of the invention, during the shift-up shift due to the reduction of the engine load, the increase period is changed to be longer as the input rotation speed of the transmission gear mechanism in the automatic transmission is larger. Since the shelf pressure is formed in correspondence with the transmission torque with higher accuracy, the durability of the friction element is further improved.

[0016]

EXAMPLES Examples of the present invention will be described below.

First, the mechanical structure of the automatic transmission according to this embodiment will be described with reference to FIG.
Is a torque converter 20 as a main component,
It has a speed change gear mechanism 30 driven by the output of the converter 20, a plurality of friction engagement elements 41 to 46 such as clutches and brakes for switching the power transmission path of the mechanism 30, and one-way clutches 51 and 52. Each of the D, S, L, and R ranges as the traveling range, the 1st to 4th speeds in the D range, the 1st to 3rd speeds in the S range, and the 1st to 2nd speeds in the L range have come to be obtained. There is.

The torque converter 20 is a pump 2 fixed in a case 21 connected to the engine output shaft 1.
2 and the pump 22 disposed so as to face the pump 22.
A turbine 23 driven by hydraulic fluid by means of a hydraulic fluid, and a stator 25 provided between the pump 22 and the turbine 23 and supported by the transmission case 11 via a one-way clutch 24 to increase the torque. The lock-up clutch 26 is provided between the case 21 and the turbine 23 and directly connects the engine output shaft 1 and the turbine 23 via the case 21. And
The rotation of the turbine 23 is output to the transmission gear mechanism 30 side via a turbine shaft 27. Here, a pump shaft 12 penetrating the inside of the turbine shaft 27 is connected to the engine output shaft 1, and the oil pump 13 provided at the rear end portion of the transmission is driven by the shaft 12.

On the other hand, the speed change gear mechanism 30 is composed of a Ravigneaux type planetary gear unit, and has a small diameter small sun gear 31 loosely fitted on the turbine shaft 27.
A large-diameter large sun gear 32 that is also loosely fitted on the turbine shaft 27 behind the sun gear 31, a plurality of short pinion gears 33 meshed with the small sun gear 31, and a front half portion meshes with the short pinion gear 33. And the latter half is the large sun gear 3
The long pinion gear 34 meshes with the second pinion gear 34, the carrier 35 that rotatably supports the long pinion gear 34 and the short pinion gear 33, and the ring gear 36 meshed with the front half of the long pinion gear 34.

A forward clutch 41 and a first one-way clutch 51 are provided in series between the turbine shaft 27 and the small sun gear 31, and a coast clutch 42 is provided in parallel with these clutches 41, 51. A 3-4 clutch 43 is provided between the turbine shaft 27 and the carrier 35, and the turbine shaft 27 and the large sun gear 3 are provided.
A reverse clutch 44 is interposed between the two. A 2-4 brake 45, which is a band brake for fixing the large sun gear 32, is provided between the large sun gear 32 and the reverse clutch 44, and between the carrier 35 and the transmission case 11. , The second one-way clutch 5 that receives the reaction force of the carrier 35
2 and a low reverse brake 4 for fixing the carrier 35
6 and 6 are provided in parallel. The ring gear 36 is connected to the output gear 14, and the rotation is transmitted from the output gear 14 to the left and right wheels (not shown) via a differential device.

Here, the friction engagement elements 41 to 46 such as the above-mentioned clutches and brakes and the one-way clutches 51 and 5 are used.
The relationship between the operation of No. 2 and the shift speed is summarized in Table 1.

[0022]

[Table 1] Next, a hydraulic control circuit for supplying and discharging hydraulic pressure to and from the actuators of the friction engagement elements 41 to 46 will be described with reference to FIG. Here, among the above-mentioned actuators, 2
The hydraulic actuator 45a of the -4 brake 45 is composed of a servo piston having an apply port 45b and a release port 45c. When the hydraulic pressure is supplied only to the apply port 45b, the 2-4 brake 45 is engaged, and both ports 45b. , 45c is not supplied with hydraulic pressure, and both ports 45b, 45c are supplied with hydraulic pressure, the 2-4 brake 45 is released. In addition, other friction engagement elements 41 to 44, 4
The actuator of 6 consists of a normal hydraulic piston,
The frictional fastening element is fastened when hydraulic pressure is supplied.

The hydraulic control circuit 60 has, as main components, a regulator valve 61 for adjusting the pressure of the hydraulic oil discharged from the oil pump 13 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 frictional engagement element (actuator) 41 that operates in accordance with the gear position.
1-2, 2-3, 3-for supplying / discharging hydraulic pressure to / from 46
4 shift valves 63, 64, and 65 are provided.

The manual valve 62 has an input port e into which the line pressure is introduced from the main line 110 and first to fourth output ports a to d. The D range and the S range communicate with the first and second output ports a and b, the L range communicates with the first and third output ports a and c, and the R range communicates with the fourth output port d. ing. And
First to fourth output lines 111 to 114 are connected to the output ports a to d, respectively.

Further, the above-mentioned 1-2, 2-3, 3-4 shift valves 63, 64, 65 each have a structure in which the spool is biased to the right side in the drawing by a spring (not shown). Pilot port 63 on the right
a, 64a, 65a are provided. And 1-2
The first pilot line 1 led from the main line 110 is introduced into the pilot port 63a of the shift valve 63.
15 is connected to the first output line 1 at the pilot ports 64a and 65a of the 2-3 and 3-4 shift valves 64 and 65.
Second and third pilot lines 117, 118 branched from 11 via a line 116 are respectively connected, and these pilot lines 115, 117,
The first, second, and third solenoid valves 66, 67, 68 for shifting are provided at 118, respectively. These solenoid valves 66 to 68 discharge hydraulic oil from the pilot lines 115, 117, 118 when they are ON, and discharge pilot pressure in the pilot ports 63a to 65a of the corresponding shift valves 63 to 65. By pressing, the spool is positioned on the right side in the drawing, and when it is OFF, the pilot port 63a ...
Pilot pressure is introduced from the pilot lines 115, 117, 118 to 65a to position the spools on the left side.

As shown in FIG. 3, the automatic transmission 10 includes solenoid valves 66 to 68, lock-up and bypass control solenoid valves 94 and 104, and a line pressure control duty solenoid. Controller 200 for controlling operation of valve 96
The controller 200 is provided with a signal from a vehicle speed sensor 201 that detects the vehicle speed of the vehicle and a throttle opening sensor 2 that detects the throttle opening of the engine.
Shift position sensor 2 for detecting the signal from the switch 02 and the position (range) of the shift lever provided in the automatic transmission.
03 and a signal from a turbine speed sensor 204 that detects the turbine speed of the torque converter 20 are input. Then, the controller 200 sets the shift solenoid valves 66 to 68 based on a shift map preset according to the vehicle speed of the vehicle and the throttle opening of the engine for each range selected by the shift lever. ON-OFF control. As a result, the positions of the spools of the shift valves 63 to 65 are switched, and the oil passages communicating with the frictional fastening elements 41 to 46 are selectively communicated with each other.
To 46 are fastened in the combinations shown in Table 1, and the gear stages are switched according to the operating state. In that case, D, S, L
Shift stages and solenoid valves 6 in the forward range of
The relationship with the ON / OFF combination patterns of 6 to 68 is set as shown in Table 2.

[0027]

[Table 2] On the other hand, the first to fourth output lines 111 to 11 connected to the output ports a to d of the manual valve 62, respectively.
Main line 1 in each D, S, L forward range of 4
The above-mentioned line 116 is branched from the first output line 111 communicated with 10, and this line 116 serves as a forward clutch line, and is guided to the forward clutch 41 via the one-way orifice 71. Therefore, the forward clutch 41 is always engaged in the D, S, and L ranges. Here, the forward clutch line 116 is connected via a line 119 to the ND accumulator 72 for buffering when the forward clutch is engaged.
Are connected.

Further, the first output line 111 is the above-mentioned 1-2.
When the spool is guided to the shift valve 63, the first solenoid valve 66 is turned on and the spool is positioned on the right side, it communicates with the servo apply line 120, and reaches the apply port 45b of the servo piston 45a through the one-way orifice 73. Therefore, when the first solenoid valve 66 is ON in the D, S, and L ranges, that is, the second, third, and fourth speeds in the D range, the second and third speeds in the S range, and the second speed in the L range.
At high speed, the hydraulic pressure (servo apply pressure) is introduced into the apply port 45b, and when the hydraulic pressure (servo release pressure) is not introduced into the release port 45c, the 2-4 brake 45 is engaged. The servo apply line 120 is also connected to a 1-2 accumulator 74 for buffering when the 2-4 brake is engaged.

In the D and S ranges, the main line 110
The second output line 112 communicating with the above is led to the 2-3 shift valve 64. Then, the line 112
Communicates with the 3-4 clutch line 121 via the one-way orifice 75 when the second solenoid valve 67 is OFF and the spool is located on the left side. Then, the line 121 further reaches the 3-4 clutch 43 via the one-way orifice 76. Therefore, when the second solenoid valve 67 is OFF in the D and S ranges, that is, the 3-4 clutch 43 is engaged in the 3rd and 4th speeds of the D range and the 3rd speed of the S range.

Here, the above-mentioned 3-4 clutch line 121
The first and second drain lines 122 and 123 are branched from the above, the first drain line 122 is led to the 3-4 shift valve 65, and the third solenoid valve 68 is turned off.
When it is FF (spool is on the left side), it communicates with the line 124 and communicates with the drain port of the 2-3 shift valve 64.
Further, the second drain line 123 is similarly guided to the 3-4 shift valve 65 via the one-way orifice 77, the fixed orifice 78 and the one-way orifice 79,
When the third solenoid valve 68 is ON (the spool is on the right side), it communicates with the line 124 and communicates with the drain port of the 2-3 shift valve 64. It should be noted that between the one-way orifice 77 and the fixed orifice 78 of the second drain line 123, there is a 2- for buffering when the 3-4 clutch is operating.
Three accumulators 80 are connected.

In addition, the second solenoid valve 67 is connected to the first drain line 122 and the second solenoid valve 67 is OFF, similarly to the 3-4 clutch line 121, and the 2-3 shift valve 6 is connected.
Second output line 1 when spool 4 is located on the left side
The line 125 communicating with the 12 includes the 3-4 shift valve 6
5 and the third solenoid valve 68 is off and the spool is located on the left side, the servo release line 12
Connect to 6. The line 126 reaches the release port 45c of the servo piston 45a via the one-way orifices 81 and 82. Therefore, when the second and third solenoid valves 67 and 68 are both OFF in the D and S ranges, that is, the third speed of the D range and the third speed of the S range, the servo release pressure is introduced into the release port 45c of the servo piston 45a. Then, the 2-4 brake 45 is released.

Further, the above servo release line 126
The line 127 branched from between the two one-way orifices 81 and 82 of the coast control valve 8
3, the one-way orifice 84 and the ball valve 85 lead to the coast clutch line 128 and reach the coast clutch 42. Therefore, the coast clutch 42 is engaged at the third speed of the D range and the third speed of the S range in which the hydraulic pressure is introduced into the servo release line 126. On the other hand, when the third solenoid valve 68 is OFF,
When the spool of the -4 shift valve 65 is located on the left side, and the second solenoid valve 67 is ON and the spool of the 2-3 shift valve 64 is located on the right side, the forward clutch line 116 has its branch line 129, Three
It communicates with the line 131 through the -4 shift valve 65, the line 130, and the 2-3 shift valve 64. This line 131 further communicates with the coast clutch line 128 via the ball valve 85, and therefore, in the coast clutch 42, the second solenoid valve 67 is turned on.
Then, when the third solenoid valve 68 is OFF, that is, the second speed in the S range and the first and second speeds in the L range are also engaged.

The third output line 11 communicating with the main line 110 in the L range by the manual valve 62.
3 is a low reducing valve 8 as a pressure reducing valve.
6 and the line 132 to the 1-2 shift valve 63. Further, this line 132 is provided with the one-way orifice 87 and the ball valve 8 when the first solenoid valve 66 is OFF and the spool is located on the left side.
8 through the low reverse brake line 133 to reach the low reverse brake 46. Therefore, L
When the first solenoid valve 66 is off in the range, that is, the first speed in the L range, the low reverse brake 46 is engaged.

Further, the fourth output line 114 communicating with the main line 110 in the R range communicates with the low reverse brake line 133 via the line 134 branched from the line 114, the one-way orifice 89 and the ball valve 88. On the other hand, the reverse clutch line 135 is formed and reaches the reverse clutch 44 via the one-way orifice 90. Therefore, in the R range, the low reverse brake 46 and the reverse clutch 44 are always engaged. Here, an NR accumulator 91 for buffering when the reverse clutch is engaged is connected to the reverse clutch line 135.

The hydraulic control circuit 60 also includes a lockup clutch 2 in the torque converter 20 shown in FIG.
A lock-up valve 92 for actuating 6 is provided. This valve 92 includes a regulator valve 6
The torque converter line 136 is guided from 1 and the pilot port 92a provided at one end is
A pilot line 137, which is branched from the main line 110 and into which the hydraulic pressure reduced by the solenoid reducing valve 93 is introduced, is connected. The solenoid valve 94 for lockup is connected to the line 137.
Is provided and the spool is positioned on the right side when the valve 94 is ON, the torque converter line 136 communicates with the torque converter in-line 138 that communicates with the torque converter 20. Lock up clutch 2
6 is concluded. In addition, the solenoid valve 94 is O
If it becomes FF and the spool moves to the left side, the torque converter line 136 moves the lockup release line 13
9, the lockup release pressure is introduced into the torque converter 20, and the lockup clutch 26 is released.

Further, the hydraulic control circuit 60 is provided with a throttle modulator valve 95, a duty solenoid valve 96 for operating the valve, and a cutback valve 97 for controlling the line pressure adjusted by the regulator valve 61. Has been.

A line 140 branched from a line 137 leading to the main line 110 is led to the throttle modulator valve 95 via the solenoid reducing valve 93, and a duty solenoid which opens and closes periodically is introduced. The pilot pressure adjusted by the valve 96 is introduced into one end of the spool, and the throttle modulator pressure is generated according to the duty ratio (valve opening time ratio in one cycle) of the duty solenoid valve 96. . In this case, the duty ratio is set according to the throttle opening of the engine, and the corresponding throttle modulator pressure is introduced into the pressure increasing port 61a of the regulator valve 61 by the line 141, The line pressure adjusted by the valve 61 increases as the throttle opening of the engine increases.

The cutback valve 97 has a line 1 branched from a line 141 for supplying the throttle modulator pressure to the regulator valve 61.
42 is guided, and the first to third ports 97a,
97b and 97c are provided, and the pilot pressure generated when the first solenoid valve 66 is OFF is supplied to the first port 97a via the line 143 and the second port 9a.
The pilot pressure generated when the second solenoid valve 67 is OFF is supplied to the line 2b via a line 144.
The pilot pressure generated when the third solenoid valve 68 is OFF is introduced into the third port 97c through the line 145.
Then, the spool moves according to the introduction state of these pilot pressures, and pilot pressure is introduced only to the first port 97a (only the first solenoid valve 66 is turned off.
1st speed of D range and 1st speed of S range, pilot pressure is introduced to the 1st and 3rd ports 97a and 97c (1st and 3rd solenoid valves 66 and 68 are OFF) 1st speed of L range In addition, pilot pressure is introduced only into the third port 97c (only the third solenoid valve 68 is turned off).
The line 142 is cut off at the second speed of the S range and the second speed of the L range, and the line 142 communicates with the line 146 at a speed other than these shift speeds, and the throttle valve is connected to the pressure reducing port 61b of the regulator valve 61. The line pressure is reduced by introducing the modulator pressure.

In addition to the above configuration, this hydraulic control circuit 6
0 is provided with a bypass valve 101, 2-3 control valve 102 and a timing valve 103 in addition to the coast control valve 83 for adjusting the hydraulic pressure supply / discharge timing at each shift.

The coast control valve 83 is
As described above, the ball valve 85 is branched from the servo release line 126 to the coast clutch line 128.
The line pressure (forward clutch pressure) is provided by a line 147 that is provided on the line 127 that communicates with the forward clutch line 116 and is branched from the forward clutch line 116.
Is led to one end of the spool. Then, when the servo release pressure introduced to the other end of the spool by the line 127 and the biasing force of the spring overcome the line pressure, the line 127 is communicated.

The bypass valve 101 has a 3-
The spool 101a is provided on a bypass line 148 that bypasses the one-way orifice 76 provided in the four-clutch line 121, and the hydraulic pressure (3-4 clutch pressure) downstream of the one-way orifice 76 of the 3-4 clutch line 121 is the spool 101a. At one end of the line 149, 1 led from the throttle modulator valve 95.
When the modulator pressure is introduced to the other end of the spool by 50, the 3-4 clutch pressure rises above a predetermined value and the spool moves to the left side, the bypass line 14
8 is cut off. Therefore, the 3-4 clutch pressure is rapidly supplied through the bypass line 148 at the start of the supply, but thereafter the one-way orifice 7
6 makes the supply slower, thus 2-3
The engagement timing of the 3-4 clutch 43 during upshifting is adjusted, and the timing is changed according to the throttle opening of the engine.

Further, the above 2-3 control valve 1
02 is provided on a bypass line 151 that bypasses the one-way orifice 81 that performs a throttle action in the hydraulic pressure supply direction on the servo release line 126, and
The hydraulic pressure (3-4 clutch pressure) in the 3-4 clutch line 121 is applied to one end of the spool, and the line 1 is applied to the center of the spool.
The above-mentioned throttle modulator pressure is introduced through the line 49 and the line 152, and the servo release pressure downstream of the bypass line 151 is introduced at the other end. Then, the bypass line 151 is opened or discharged by the action of the 3-4 clutch pressure, the throttle modulator pressure, and the servo release pressure, and the servo release pressure is adjusted corresponding to the 3-4 clutch pressure. ing.

The timing valve 103 is the one-way orifice 7 on the servo apply line 120.
The first bypass line 153 that bypasses 3 and the one-way orifice 8 on the servo release line 126.
Second bypass line 15 bypassing 2 (and 81)
4 and the second drain line 123 having the above 3-4 clutch pressure
Is provided across the third bypass line 155 that bypasses the fixed orifice 78 (and the one-way orifice 79). A pilot line 156 led from the main line 110 is connected to one end of the spool, and a solenoid valve 104 for bypass control is provided in the line 156.

The timing valve 103 opens and closes the first to third bypass lines 153, 154 and 155 by the operation of the solenoid valve 104.

The automatic transmission 10 according to this embodiment has the above-described structure. In this automatic transmission 10, for example,
The following control is performed during the -2 shift.

That is, at the time of the 1-2 shift, the 2-4 brake 45 is engaged as shown in Table 1, but in that case, the normal schedule-up shift and the back-out shift are 2 shifts. -4 Appropriate hydraulic pressure (servo apply pressure) corresponding to the transmission torque in the apply port 45c of the servo piston 45a in the brake 45
Is not supplied, the slip time of the 2-4 brake 45 becomes long and durability deteriorates due to lack of torque transmission capacity particularly during backout gear shift with large rotation fluctuation.

Therefore, in this embodiment, the solenoid valve 10 for bypass control is provided at the beginning of the 1-2 shift.
By operating No. 4, the first bypass line 153 that bypasses the one-way orifice 73 on the servo apply line 120 is opened via the timing valve 103, and the bypass control for increasing the flow rate of the hydraulic oil is performed. However, this bypass control is specifically performed as follows according to the flowchart of FIG.

That is, the controller 200 reads various signals in step S1 and then 1 in step S2.
If the value of the shift flag F indicating that the shift is being performed is -2, and if it is determined that the shift flag F is set to 1, the process proceeds to step S3 and the shift flag F is set 1 sampling time Δt before. It is determined whether it is set to 1. That is, it is generated whether or not the 1-2 shift command is output. Then, in step S3, the shift flag F is set to 1 before the sampling time Δt.
If it is determined that it is not set to step S
4, the actual time t at that time is stored as the shift start time t _S , and the previous value (θ−Δt) is subtracted from the current value θ (t) of the throttle opening θ in step S5. Throttle change rate Δθ is the predetermined backout judgment value α
Is smaller than. Here, the backout determination value α is set to a negative value in which the throttle change rate Δθ is close to 0, and when the throttle opening θ changes by more than the backout determination value α, it means that the backout shift is performed. Will be judged.

When the controller 200 determines in step S5 that the throttle change rate Δθ is not smaller than the backout determination value α, step S5.
After proceeding to step 6 and setting a predetermined value t ₀ as the bypass time t _X , an ON signal is output to the bypass control solenoid valve 104 in step S7 and then the process returns to step S1.

Since the shift flag F is set to 1 during the shift operation, the controller 20
For 0, after the second time, the process branches from step S3 to step S8, and it is determined whether or not the value obtained by subtracting the shift start time t _S from the actual time t is greater than the bypass time t _X. That is, it is determined whether or not the set bypass time t _X has elapsed since the 1-2 shift was started. And
The controller 200 returns Y in step S8.
When it is determined to be ES, the process proceeds to step S9, an OFF signal is output to the bypass control solenoid valve 104, and the process returns to step S1.

On the other hand, when the controller 200 determines in step S5 that the throttle change rate Δθ is smaller than the backout determination value α, step S10
And the actual turbine rotation speed N _T is applied to the bypass time function f (N _T ) set by using the turbine rotation speed as a parameter to set the bypass time t _X. Here, the bypass time function f
(N _T ) is set so that the bypass time becomes longer as the turbine speed N _T becomes higher, and at the same time, it is set at least longer than the predetermined value t ₀ .

With the above arrangement, the following effects can be obtained.

That is, during the 1-2 schedule upshift, as shown in FIG. 6, the bypass control solenoid valve 104 is turned on until the actual time t reaches a predetermined value t ₀ from the shift start time t _S. That is, as shown in FIG. 7, the spool of the timing valve 103 is located on the right side, and the first bypass line 153 that bypasses the one-way orifice 73 on the servo apply line 120 is opened.

In this case, during the 1-2 shift-up shift, the 1-2 shift valve 63 is switched by switching the first solenoid valve 66 from OFF to ON.
The spool will be located on the right side. Therefore,
By connecting the first output line 111 to the servo apply line 120, the servo apply pressure is supplied to the apply port 45b of the servo piston 45a. As described above, the timing valve 103 is used.
Since the spool is located on the right side, most of the hydraulic oil passes through the first bypass line 153 and the servo piston 45.
a apply port 45b and 1-2 accumulator 7
4 and 4 are distributed and supplied. As a result, reference numeral (a) in FIG.
As shown by, the servo apply pressure rises rapidly.

On the other hand, when the actual time t reaches the predetermined value t ₀ , the bypass control solenoid valve 104 is turned off.
Therefore, as shown in FIG.
The spool of 3 will move from the right side to the left side,
The first bypass line 153 is cut off. Therefore,
Servo apply pressure is one way orifice 73 and 1
As a result of the action with the −2 accumulator 74, the pressure rises in a gentle shelf pressure state as shown by the symbol (b) in FIG. 6, and the 2-4 brake 45 is engaged in the process.

On the other hand, during backout gear shifting, a bypass time t ₁ longer than the predetermined value t ₀ is set. Therefore, as shown in FIG. 9, the one-way orifice 73 is bypassed for a longer time than during the schedule-up shift, and when the first bypass line 153 is blocked by the timing valve 103, the shelf pressure level is changed during the schedule-up shift. Will be relatively higher than. As a result, the turbine speed N
_{Even if} the variation amount of _T is large, the 2-4 brake 45 is quickly engaged. In that case, the turbine speed N _T
The larger the value is, the longer the bypass time is set, so that the shelf pressure appropriately corresponding to the transmission torque is formed, and the 2-4 brake 45 is reliably engaged.

In this embodiment, the bypass line 148 that bypasses the one-way orifice 76 on the 3-4 clutch line is opened and closed by the feedback type bypass valve 101. If the opening / closing system is changed to the same opening / closing system as 103, the shelf pressure level can be changed by the schedule-up shift and the back-out shift even during the 2-3 shift in which the 3-4 clutch 43 is engaged.

[0058]

As described above, according to the present invention, at the time of upshifting due to a decrease in engine load, the initial increase time of the engaging hydraulic pressure supplied to the frictional engagement element is higher than at the time of upshifting due to an increase in vehicle speed. Therefore, the amount of hydraulic oil flowing into the accumulator increases, and the shelf pressure supplied to the frictional engagement element increases. Therefore, if this increase period is set appropriately, a shelf pressure appropriately corresponding to the transmission torque is formed at any shift-up shift, so that the engaging operation of the friction element is favorably performed. It will be done and the durability will be improved.

In particular, in the third aspect of the invention, at the time of shift-up shifting due to a reduction in engine load, the increasing period is changed so as to increase as the input rotation speed of the transmission gear mechanism in the automatic transmission increases. Since the shelf pressure is formed in correspondence with the transmission torque with higher accuracy, the durability of the friction element is further improved.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing a mechanical configuration of an automatic transmission.

FIG. 2 is a circuit diagram showing a hydraulic control circuit.

FIG. 3 is a control system diagram of an automatic transmission.

FIG. 4 is a flowchart showing bypass control by a controller.

FIG. 5 is an explanatory diagram of a map used for the control.

FIG. 6 is a time chart showing the operation of the embodiment at the time of schedule up shifting.

FIG. 7 is an enlarged view of a main part of a hydraulic control circuit during a 1-2 shift operation.

FIG. 8 is an enlarged view of the essential part of the hydraulic control circuit during the 1-2 shift operation.

FIG. 9 is a time chart showing an operation during backout gear shifting.

FIG. 10 is an operating region diagram showing types of 1-2 shift.

FIG. 11 is a time chart showing a change in turbine rotational speed during a gear shifting operation, which shows a conventional problem.

[Explanation of symbols]

 10 Automatic Transmission 30 Shift Gear Mechanism 45 2-4 Brake 45a Servo Piston 45b Apply Port 63 1-2 Shift Valve 66 First Solenoid Valve 74 1-2 Accumulator 103 Timing Valve 104 Solenoid Valve 200 Controller 204 Turbine Speed Sensor

Claims (3)

[Claims] 1. A hydraulic control circuit comprising: a plurality of friction engagement elements for switching power transmission paths of a speed change gear mechanism; and a hydraulic control circuit for controlling supply and discharge of working hydraulic pressure to and from hydraulic actuators of these friction engagement elements. In the hydraulic pressure supply passage for supplying the hydraulic oil pressure to the predetermined frictional engagement element, an automatic speed changer is provided which has an accumulator for storing the hydraulic oil and a flow rate adjusting means arranged upstream of the accumulator for adjusting the flow rate of the hydraulic oil. A shift control device for a machine, the control means operating the flow rate adjusting means so as to increase the flow rate of the hydraulic fluid for a predetermined period at the initial stage of shifting when the predetermined frictional engagement element is engaged, and a reduction in engine load. When the shift-up shift is performed by the vehicle, the increase period changing means for increasing the increase period as compared with the shift-up shift by increasing the vehicle speed is provided. Shift control device for automatic transmissions. 2. A hydraulic control circuit, comprising: a plurality of friction engagement elements for switching power transmission paths of a speed change gear mechanism; and a hydraulic control circuit for controlling supply and discharge of operating hydraulic pressure to and from hydraulic actuators of these friction engagement elements. In a hydraulic pressure supply passage for supplying an operating hydraulic pressure to a predetermined friction engagement element, an accumulator for storing hydraulic oil, a throttle element arranged upstream of the accumulator, a bypass passage bypassing the throttle element, and a bypass passage A shift control device for an automatic transmission, comprising: an opening / closing means for opening / closing a passage, wherein the opening / closing means is operated so that the bypass passage is opened for a predetermined period at an initial stage of gear shifting when the predetermined friction engagement element is engaged. Control means and the shift-up shift by increasing the vehicle speed during the opening period of the bypass passage at the time of shift-up due to the reduction of the engine load. A shift control device for an automatic transmission, comprising: an opening period changing means that is longer than the time. 3. A hydraulic control circuit, comprising: a plurality of friction engagement elements for switching power transmission paths of a speed change gear mechanism; and a hydraulic control circuit for controlling supply and discharge of operating hydraulic pressure to and from hydraulic actuators of these friction engagement elements. In the hydraulic pressure supply passage for supplying the hydraulic oil pressure to the predetermined frictional engagement element, an automatic speed changer is provided which has an accumulator for storing the hydraulic oil and a flow rate adjusting means arranged upstream of the accumulator for adjusting the flow rate of the hydraulic oil. A shift control device for a machine, the input rotation speed detecting means for detecting an input rotation speed of the speed change gear mechanism,
At the initial stage of gear shift when the predetermined friction engagement element is engaged, control means for operating the flow rate adjusting means so as to increase the flow rate of hydraulic oil for a predetermined period, and the increasing period during the shift-up shift due to a decrease in engine load. And an increase period changing means for making the increase period longer as the input speed increases when the shift up shift is started. Shift control device for automatic transmission.