JPH06100270B2 - Automatic transmission control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention operates a lockup mechanism interposed between the input and output shafts of a fluid torque converter according to the vehicle speed and the like, and at the time of gear shifting, the lockup mechanism The present invention relates to a control device for an automatic transmission that controls so as to temporarily release an operating state.

(Prior Art) Conventionally, as an automatic transmission mounted on a vehicle, a hydraulic torque converter and a multi-stage gear type speed change mechanism having a gear mechanism such as a planetary gear mechanism are combined and widely used. Shift control such as shift-up control and shift-down control in an automatic transmission equipped with such a fluid torque converter is usually performed by providing a hydraulic control circuit. That is, for example, a hydraulic control circuit is switched by a mechanical or electromagnetic switching valve, whereby friction elements such as a brake and a clutch associated with a multi-stage gear type speed change mechanism are appropriately actuated to switch the engine power transmission path,
The required gear shift is performed. Then, for example, when the hydraulic control circuit is switched by the electromagnetic switching valve to switch the shift speed, the electronic detection device detects that the running state of the vehicle exceeds a predetermined shift line, and this device detects It is customary to selectively actuate the solenoid operated directional control valve in response to this signal to switch the hydraulic control circuit. By the way, in the automatic transmission equipped with the fluid torque converter as described above, since the fluid torque converter transmits power through the fluid, the vehicle equipped with the fluid torque converter is capable of running smoothly, but Fuel efficiency is not good because of the energy loss due to slippage.

For this reason, a lockup mechanism is provided in the fluid torque converter, and when the vehicle speed and the engine load exceed a predetermined value, this lockup mechanism is activated to operate the input / output shaft of the fluid torque converter, and thus the output shaft of the engine and the fluid. An automatic transmission that locks up (directly connects) with the output shaft of a torque converter has been put into practical use. In the automatic transmission equipped with the fluid torque converter with the lockup mechanism as described above, the shift control as described above, that is,
Lock-up control is required in addition to shift-up control and shift-down control. In this lock-up control, in order to avoid a large shock caused by shifting gears while the lock-up mechanism is in the operating state, the lock-up mechanism is temporarily operated during shifting even if the lock-up mechanism should be activated. The control to cancel is performed.

However, if the lockup is released during acceleration by pressing the accelerator pedal, the engine speed rapidly increases by the amount of the slip of the fluid torque converter, but in the case of upshift control, the engine speed will be lowered, so If the release timing is too early, the engine speed will rise once, causing so-called engine upswing, and then the engine speed will drop.
There is a problem of causing a phenomenon that is uncomfortable for the driver.

Therefore, as a measure against such a problem, for example, Japanese Patent Laid-Open No. 56-1
As described in Japanese Patent No. 27856, delaying a lock-up release signal for releasing the lock-up mechanism during shift control from the shift-up signal for causing the multi-step gear type transmission mechanism to shift up by a predetermined time. , A control method has been proposed in which the lockup mechanism and the multistage gear type speed change mechanism are sent to a hydraulic control circuit provided with a hydraulic actuator.

On the other hand, in the case of the shift-down control, since the engine speed needs to be increased by the gear ratio, the engine blow-up as described above hardly poses a problem.
If the lock-up release timing and the shift-down timing are close to each other, the vehicle speed will fluctuate abruptly and the driving will be temporarily unstable under the condition that the engine speed fluctuates due to the shift shock. There is an inconvenience. Therefore, for example, as disclosed in Japanese Patent Laid-Open No. 56-39354, lock-up is first released during shift-down control, and abrupt engine speed fluctuations that occur at this time are mitigated via a torque converter. , The automatic downshift is designed to reduce the shock at the time of shifting or unstable fluctuation of vehicle speed by delaying the downshifting time after a predetermined time from the lockup release, that is, until the engine operating state stabilizes. A machine controller has been proposed.

However, when the shift-down control is performed after the predetermined time has elapsed from the lock-up release during the shift-down control as described above, the shift-down timing is originally set to be excessive to prevent a large shift shock or the like. May be delayed unnecessarily. For this reason, normally, during shift down control, it is desired that a speed change step is quickly performed for overtaking, and therefore, the shift down time after the lockup is released is
There is a demand for a control device for an automatic transmission that can be appropriately controlled without delaying more than necessary.

(Object of the Invention) In view of the above point, the present invention provides an operation for locking up a lockup mechanism interposed between an output shaft of an engine and an output shaft of a torque converter connected to the output shaft according to a vehicle speed or the like. In addition, the lock-up mechanism is not released from the operating state during the shift control, and the lock-up mechanism is released from the shift-down period during the shift-down control. The present invention provides a control device for an automatic transmission, which is configured to reduce the shock at the time of gear shifting and to perform the downshift at an appropriate timing without being delayed more than necessary after releasing the lockup. To aim.

(Structure of the Invention) A control device for an automatic transmission according to the present invention includes a lockup mechanism that selectively locks up an output shaft of an engine and an output shaft of a torque converter connected thereto, and an output shaft of the torque converter. A hydraulic control circuit having a speed-change electromagnetic means for switching the power transmission path of the speed-change gear mechanism connected to the engine and a lock-up electromagnetic means for actuating or releasing the lock-up mechanism; The engine load sensor that detects the corresponding information, the speed sensor that detects the output shaft speed of the engine and the output shaft speed of the torque converter, or the information corresponding to these, and the signals that are obtained from the engine load sensor and the speed sensor On the other hand, a shift control for sending a shift-up signal or a shift-down signal to the electromagnetic means for shifting the shift speed. Means, a lock-up control means for sending a lock-up actuation signal or a lock-up release signal to the lock-up electromagnetic means based on the signals obtained from the engine load sensor and the speed sensor, and the output shaft speed of the engine. Find the difference between the torque converter output shaft speed and
When the shift-down signal is transmitted from the shift control means together with the transmission of the lock-up release signal from the lock-up control means, the difference between the determined output shaft speed of the engine and the output shaft speed of the torque converter. Delaying means for delaying the supply of the downshift signal to the electromagnetic means for switching the shift stage until is equal to or more than a predetermined value.

By doing so, during the downshift control of the automatic transmission having the torque converter provided with the lockup mechanism, the downshifting is performed after the lockup release signal is sent from the lockup control means to the electromagnetic means for lockup. In this case, the shift control means supplies the downshift signal to the shift switching electromagnetic means at an appropriate timing when the difference between the output shaft speed of the engine and the output shaft speed of the torque converter opens. As a result, it is possible to effectively suppress the occurrence of shock associated with the shift-down control and prevent the shift-down timing from being delayed more than necessary.

(Example) Hereinafter, the Example of this invention is described with reference to drawings.

FIG. 1 shows a cross section of a mechanical portion of an automatic transmission to which the control device for an automatic transmission according to the present invention is applied, and a hydraulic control circuit accompanying the mechanical portion. In FIG. 1, the automatic transmission
The AT is a torque converter 10, a multi-stage gear transmission mechanism 20,
It is configured to include an overdrive planetary gear transmission mechanism 50 arranged between the torque converter 10 and the multi-stage gear transmission mechanism 20.

The torque converter 10 includes a pump 11 that is coupled to the engine output shaft 1 and is driven to rotate, a turbine 12 that is disposed opposite to the pump 11, and a stator 13 that is disposed between the pump 11 and the turbine 12. , The output shaft of the turbine 12
14, and thus the output shaft 14 of the torque converter 10 is coupled. A lockup clutch 15 is arranged between the output shaft 14 of the torque converter 10 and the pump 11. The lock-up clutch 15 is constantly urged by the hydraulic pressure circulating in the torque converter 10 in the engagement direction, that is, in the direction in which the engine output shaft 1 and the output shaft 14 of the torque converter 10 are locked up (directly connected). At the same time, the hydraulic pressure for opening supplied from the outside presses it in the direction opposite to the engaging direction (direct coupling direction) to open it.

The multi-stage gear speed change mechanism 20 has a front stage planetary gear mechanism 21 and a rear stage planetary gear mechanism 22, and the sun gear 23 of the front stage planetary gear mechanism 21 and the sun gear 24 of the rear stage planetary gear mechanism 22 are connected via a connecting shaft 25. . The input shaft 26 of the multi-stage gear transmission 20 is connected to the connecting shaft 25 via the front clutch 27 and to the internal gear 29 of the front planetary gear mechanism 21 via the rear clutch 28, respectively. A front brake 30 is provided between the connecting shaft 25, that is, the sun gears 23 and 24 and the transmission case. The planetary carrier 31 of the front planetary gear mechanism 21 and the internal gear 33 of the rear planetary gear mechanism 22 are connected to the output shaft 34, and the rear brake 36 is provided between the planetary carrier 35 of the rear planetary gear mechanism 22 and the transmission case. A one-way clutch 37 is provided.

In the overdrive planetary gear speed change mechanism 50, a planetary carrier 52 that rotatably supports a planetary gear 51 is connected to the output shaft 14 of the torque converter 10, and a sun gear 53 is connected to an internal gear 55 via a direct coupling clutch 54. It is like this. An overdrive brake 56 is provided between the sun gear 53 and the transmission case, and the internal gear 55 is connected to the input shaft 26 of the multistage gear transmission mechanism 20.

The multi-stage gear transmission mechanism 20 is of a known type and has three forward gears and one reverse gear.
It has a gear shift stage, clutches 27 and 28, and a brake.
By operating 30 and 36 as appropriate, the required shift speed can be obtained. The overdrive planetary gear speed change mechanism 50 connects the output shaft 14 of the torque converter 10 and the input shaft 26 of the multi-step gear speed change mechanism 20 in a direct connection state when the direct connection clutch 54 is engaged and the overdrive brake 56 is released. When the overdrive brake 56 is engaged and the clutch 54 is released, the output shaft 14 of the torque converter 10 and the output shaft 26 of the multi-stage gear speed change mechanism 20 are connected in the overdrive state.

The automatic transmission AT having the mechanical parts as described above
Is also associated with a hydraulic control circuit CK. This hydraulic control circuit CK has an oil pump 100 driven by the engine output shaft 1 and is connected to a pressure line from the oil pump 100.
The pressure of the hydraulic oil discharged to 101 is adjusted by the pressure adjusting valve 102 and is guided to the select valve 103. Select valve 103 is 1,
It has shift positions of 2, D, N, R, P, and this select valve 103
When in position 1, 2 and P, pressure line 101 is select valve
It communicates with ports a, b and c of 103. Port a is connected to the actuating actuator 104 of the rear clutch 28 and when the select valve 103 is in the position described above, the rear clutch 28 is
Are held in the engaged state. The port a is also connected to the vicinity of the left end of the 1-2 shift valve 110 and pushes its spool to the right in the figure. The port a is further connected to the right end of the 1-2 shift valve 110 via the first line L1.
At the right end of the 2-3 shift valve 120 via the second line L2,
The 3-4 shift valves 130 are connected to the right ends of the 3-4 shift valves 130 through the third lines L3, respectively. First, second and third lines L1, L2 and L
From 3, the first, second and third drain lines DL1, DL2, respectively
And DL3 are branched, and these drain lines DL1, D
L2 and DL3 have first, second and third solenoid valves SL1, SL2 and S for opening and closing the drain lines DL1, DL2 and DL3.
L3 is connected. Each solenoid valve SL1, SL2 and SL3
Is excited when the pressure line 101 and the port a communicate with each other, the drain lines DL1, DL2 and DL3 are opened,
As a result, the pressure in each of the lines L1, L2 and L3 is reduced.

Port b is also connected to the second lock valve 105 via line 140, and this pressure acts to push the spool of the second lock valve 105 downward in the figure. When the spool of the second lock valve 105 is at the lower position, the line 140 and the line 141 communicate with each other and hydraulic pressure is introduced into the engagement side pressure chamber of the actuator 108 of the front brake 30 to hold the front brake 30 in the operating direction. The port c is connected to the second lock valve 105, and this pressure acts to push the spool of the second lock valve 105 upward. Further, the port c is connected to the 2-3 shift valve 120 via the pressure line 106. This line 106 is the second drain line D
The second solenoid valve SL2 of L2 is demagnetized and the second line L2
The internal pressure is increased, and this pressure causes 2-3 shift valve 120.
When the spool is moved to the left, it communicates with the line 107. The line 107 is connected to the release side pressure chamber of the actuator 108 of the front brake 30, and when hydraulic pressure is introduced into this pressure chamber, the actuator 108 resists the pressure of the engagement side pressure chamber and releases the front brake 30 in the releasing direction. To activate. Further, the pressure in the line 107 is also guided to the actuator 109 of the front clutch 27 and engages the front clutch 27.

The select valve 103 has in one position a port d leading to the pressure line 101, this port d reaching the 1-2 shift valve 110 via line 112 and further connected via line 113 to the actuator 114 of the rear brake 36. It When the solenoid valves SL1 and SL2 are demagnetized by a predetermined signal, the 1-2 shift valve 110 and the 2-3 shift valve 120 move the spools to switch the lines, whereby a predetermined brake or clutch is released. It operates and the gear shifting operation of 1-2 and 2-3 is performed, respectively. The hydraulic control circuit CK includes a cutback valve 115 for stabilizing the hydraulic pressure from the pressure regulating valve 102, a vacuum throttle valve 116 for changing the line pressure from the pressure regulating valve 102 according to the magnitude of the intake negative pressure, and this throttle valve.
A throttle backup valve 117 is provided to assist the 116.

Further, the hydraulic control circuit CK includes the clutch 54 and the overdrive brake of the planetary gear speed change mechanism 50 for overdrive.
A 3-4 shift valve 130 and an actuator 132 are provided to control 56. The engagement side pressure chamber of the actuator 132 is connected to the pressure line 101, and the pressure of this line 101 pushes the overdrive brake 56 in the engagement direction. Like the 1-2 and 23 shift valves 110 and 120 described above, the spool valve 131 of the 3-4 shift valve 130 moves downward when the third solenoid valve SL3 is demagnetized. The pressure line 101 and the line 122 are cut off, and the hydraulic pressure in the line 122 is discharged. As a result, the hydraulic pressure acting on the pressure chamber on the release side of the actuator 132 of the overdrive brake 56 disappears, the overdrive brake 56 is operated in the engaging direction, and the clutch
The actuator 134 of 54 acts to disengage the clutch 54.

Further, the hydraulic control circuit CK is provided with a lockup control valve 133, and the lockup control valve 133 is connected to the port a of the select valve 103 via the fourth line L4. From this fourth line L4, each drain line DL1,
Similar to DL2 and DL3, the fourth drain line DL4 provided with the fourth solenoid valve SL4 is branched. In the lockup control valve 133, the fourth solenoid valve SL4 is excited (ON), the fourth drain line DL4 is closed, and the fourth line L4 is closed.
When the pressure in the inside increases, the spool shuts off the line 123 and the line 124, the hydraulic pressure in the line 124 is discharged, and the lockup clutch 15 is engaged, and thus the output shaft of the engine output shaft 1 and the output shaft of the torque converter 10. It is designed to be moved in the direction in which it is directly connected to 14.

In the above configuration, the following table shows the operational relationship between each shift speed and lockup and each solenoid valve, and the operational relationship between each shift speed and clutch and brake.

FIG. 2 shows an example of a control device for an automatic transmission according to the present invention, which controls the hydraulic control circuit CK associated with the automatic transmission AT as described above to perform shift control and lockup control. , Engine EN with automatic transmission AT incorporated.

In this example, a lockup control circuit 5 that performs lockup control for the automatic transmission AT, a gearshift control circuit 6 that performs gearshift control, the rotation speed of the output shaft 1 of the engine EN and the rotation of the output shaft 14 of the torque converter 10. Rotational speed difference detection circuit 7 and shift control circuit 6 for detecting when the difference between the rotational speed and the rotational speed exceeds a predetermined value
A minute time delay circuit 8 ', a delay switch 8, and an AND gate circuit 9a and a set circuit arranged between the lockup control circuit 5 and the rotational speed difference detection circuit 7 and the delay switch 8 A control unit 200 including a reset flip-flop circuit (RS FF) 9b is provided. Further, the output shaft 14 of the torque converter 10 of the automatic transmission AT, and thus the turbine speed sensor TS provided with the rotation speed Tsp of the turbine 12, is connected to the output shaft 1 of the engine EN.
The engine speed sensor ES detects the rotational speed Esp of the engine EN, and the engine load sensor LS detects the throttle opening TH of the throttle valve 3 provided in the intake passage 2 of the engine EN.

The turbine rotation speed signal St obtained from the turbine rotation speed sensor TS is supplied to the rotation speed difference detection circuit 7, the lockup control circuit 5 and the shift control circuit 6, and the throttle opening signal obtained from the engine load sensor LS. Sn is supplied to the lockup control circuit 5 and the shift control circuit 6, and further, the engine speed signal Se obtained from the engine speed sensor ES is supplied to the rotation speed difference detection circuit 7. Note that, here, the turbine speed Tsp is treated as the vehicle speed, and the throttle opening TH is treated as the engine load, respectively, as information corresponding thereto.

The rotation speed difference detection circuit 7 obtains a difference between the turbine rotation speed Tsp and the engine rotation speed Esp based on the turbine rotation speed signal St and the engine rotation speed signal Se, and when the difference becomes equal to or more than a predetermined value. Is detected, and the rotation speed difference signal Sd is transmitted when such detection is performed. The delay switch 8 sends the shift-down signal Cp ′ sent from the shift control circuit 6 to the hydraulic control circuit CK under the predetermined condition.
It is designed to be delayed by a time determined according to.

Then, the shift control circuit 6 of the control unit 200 uses the turbine rotation speed signal S from the turbine rotation speed sensor TS described above.
t, information indicating the throttle opening signal Sn from the engine load sensor LS and the traveling mode signal obtained from a mode sensor for detecting a traveling mode (not shown), for example, turbine rotational speed as shown in FIG. The shift-up shift line and the shift-down shift line of the shift map determined based on the load characteristics are collated to calculate whether or not to shift. Then, according to the result, the shift-up signal Cp or the shift-down signal Cp ′ is sent to the first, second and third solenoid valves of the hydraulic control circuit CK directly or by the minute time delay circuit 8 ′ via the delay switch 8. SL1, SL
2 and SL3, and selectively excite them in a manner as shown in Table 1 to shift the gear stage of the automatic transmission AT to a higher gear stage (shift up) or a lower gear stage (shift down). The lock-up control circuit 5 is supplied with the shift-up signal Cp or the shift-down signal Cp '.

Further, the lockup control circuit 5 uses the turbine rotation speed signal St from the turbine rotation speed sensor TS and the engine load sensor L.
The information represented by the throttle opening signal Sn and the running mode signal from S is, for example, the lockup operation line and the lockup operating line of the shift map determined based on the turbine speed-engine load characteristic as shown in FIG. Comparing with the lock-up release line, the calculation as to whether or not lock-up should be performed or whether or not lock-up should be released is performed, and the lock-up operation signal Cq or lock-up release signal Cq 'is calculated according to the calculation result. Hydraulic control circuit CK fourth solenoid valve SL
Supply to 4. When the lockup operation signal Cq is supplied to the fourth solenoid valve SL4, it is excited to activate the lockup clutch 15, and the lockup release signal Cq is supplied to the fourth solenoid valve SL4. When the lockup clutch 15 is released, it is demagnetized and the lockup clutch 15 is released.

The shift-down signal Cp ′ from the shift control circuit 6 and the lock-up operation signal Cq from the lock-up control circuit 5 are respectively supplied to a pair of input terminals of the AND gate circuit 9a, and the output of the AND gate circuit 9a is RS FF. 9b set end (S)
Is supplied to. Further, the rotation speed difference signal Sd from the rotation speed difference detection circuit 7 is supplied to the reset terminal (R) of the RS FF 9b. The output end of RS FF 9b is supplied to the control end of the delay switch 8 for on / off control. Here, RS FF 9b is set when the lock-up operation signal Cq is obtained and the shift-down signal Cp ′ is transmitted, and produces an output only in the set state, thereby turning off the delay switch 8. State. The delay switch 8 is maintained in the ON state when the output of RS FF 9b is not obtained, and when it is in the ON state, the shift down signal from the shift control circuit 6 is received.
Cp 'to the first, second and third solenoid valves SL1, SL2 and SL3
Can be supplied to.

As described above, in the example of the control device for the automatic transmission according to the present invention, the shift control and the lockup control of the automatic transmission AT are the shift-up signal Cp or the shift-down signal Cp 'and the lock-up operation signal Cq or the lock-up release. signal
This is done based on Cq ′, but in particular, the lockup clutch 15 is released from the operating state before the shift stage of the automatic transmission AT is downshifted, and the downshift is performed at an appropriate time thereafter. It is a characteristic thing to make it do, and that is mainly described below.

Based on the turbine rotation speed signal St and the throttle opening signal Sn supplied from the turbine rotation speed sensor TS and the engine load sensor LS to the lockup control circuit 5, the turbine rotation speed Tsp with respect to the throttle opening TH 'at that time. ′
However, for example, when the lock-up operation line of the map shown in FIG.
The lockup operation signal Cq is supplied from the lockup control circuit 5 to the fourth solenoid valve SL4 of the hydraulic control circuit CK, the fourth solenoid valve SL4 is excited, and the lockup clutch 1
5 is activated (direct connection).

When the lockup clutch 15 is in the operating state, the turbine speed Tsp ′ with respect to the throttle opening TH ′ at that time
3 is below the shift-down shift line in the above-mentioned map as shown in FIG. 3, the shift-down control circuit 6 immediately generates the shift-down signal Cp 'and the lock-up control circuit 5 and the minute time delay circuit are generated. 8 '. At this time, the output of the AND gate circuit 9a is supplied to the set terminal (S) of the RS FF 9b, and its output is delayed switch 8
Of the delay switch 8 is turned off. Delay switch 8 is then RS FF
The off state is maintained until the rotation speed difference signal Sd is supplied to the reset terminal (R) of 9b. At this time, the shift-down signal Cp 'from the shift control circuit 6 reaches the delay switch 8 which is in the OFF state after being delayed by the minute time .tau. By the minute time delay circuit 8', and is therefore stopped by the delay switch 8. . When the shift-down signal Cp ′ is supplied to the lockup control circuit 5, the lockup control circuit 5
Immediately, a lockup release signal Cq 'is generated to release the operating state of the lockup clutch 15 and is sent to the fourth solenoid valve SL4 of the hydraulic control circuit CK. As a result, the fourth solenoid valve SL4 is demagnetized, and the operating state of the lockup clutch 15 is released.

The changes in the engine speed Esp and the turbine speed Tsp at this time are shown in FIG. 4B when the vertical axis represents the rotational speed (rpm) and the horizontal axis represents the time t, as shown in FIG. 4A. At the time of transmission of the downshift signal Cp ′, t ₁ , there is almost no difference between the engine speed Esp and the turbine speed Tsp, but after time t ₁ , the difference gradually increases with the passage of time. Become. Here, the difference between the turbine rotation speed Tsp and the engine rotation speed Esp, that is, the slip amount of the torque converter 10 can be calculated according to the characteristic held by the torque converter 10. ΔTsp
Then, it can be expressed as ΔTsp = k · TH / Tsp (where k is a constant and TH is a throttle opening).

The rotation speed difference detection circuit 7 locks this slip amount ΔTsp, in particular, the planned slip amount ΔTsp when the operating state of the lockup clutch 15 is completely released, at the time point t _{1, that} is, the downshift signal Cp ′. It is calculated in advance at the time of being supplied to the up control circuit 5, and the calculated planned slip amount ΔTsp
In addition, for example, an operational delay of the hydraulic system in the hydraulic control circuit CK is estimated and corrected in advance to obtain the theoretical slip amount ΔTspc.
Further, the difference ΔTspr between the actual engine speed Esp and the turbine speed Tsp at that time is calculated, and this ΔTspr is calculated.
Time point t ₂ when spr becomes equal to or larger than the theoretical slip amount ΔTspc
Then, the speed difference signal Sd is input to the reset terminal (R) of RS FF 9b.
Is sent. As a result, the output from RS FF 9b is not obtained, the delay switch 8 is turned on, and the shift down signal Cp ′ is sent from the delay switch 8 to the hydraulic control circuit CK.
Is supplied to the first, second and third solenoid valves SL1, SL2 and SL3, and the downshift control of the shift speed is performed.

As described above, in this example, at the time point t ₁ when the downshift signal Cp ′ is transmitted from the shift control circuit 6, the lockup clutch is released.
In addition to releasing the operating state of 15, the shift switch circuit 6 supplies the downshift signal Cp ′ to the first, second and third solenoid valves SL1, SL2 and SL3 with the delay switch 8
Therefore, the difference between the turbine rotation speed Tsp and the engine rotation speed Esp is delayed by a predetermined value or more, that is, it is delayed until a time point t ₂ at which the slip amount is equal to or more when the release of the lockup is completed. The timing at which the shift stage of the automatic transmission AT is shifted down can be appropriately determined without being delayed more than necessary after releasing the lockup. Under such circumstances, the difference between the output shaft speed of the engine and the output shaft speed of the torque converter is controlled by the portion including the speed difference detection circuit 7, the delay switch 8, the AND gate circuit 9a and the RS FF 9b. When the shift-down signal Cp ′ is sent from the shift control circuit 6 along with sending of the lock-up release signal Cq ′ from the lock-up control circuit 5, the output shaft speed of the engine and the output of the torque converter obtained Shift down signal C until the difference with the shaft speed exceeds a specified value.
A delay means for delaying the supply of p ′ to the hydraulic control circuit CK is configured.

The control unit 200 that performs the control as described above is, for example,
It is supposed to be composed of a microcomputer,
The operation program of the microcomputer constituting the control unit 200 is executed according to the flowcharts shown in FIG.

FIG. 5 shows an overall flow of the shift control, and the shift control is first performed from the initialization setting in the process P1. In this initialization setting, the ports of each control valve for switching the hydraulic control circuit of the automatic transmission and the necessary counters are initialized to set the multistage gear transmission mechanism 20 to the first speed and the lockup clutch 15 to the disengagement. .
After that, various working areas of the control unit 200 are initialized and completed.

Next, in process P2, the position of the select valve 103, that is, the shift range is read. Then, the decision D3 determines whether or not the read shift range is "1 range". When the shift range is "1 range", the lockup is released in process P4, and then the process P5 shifts down to the first speed to calculate whether or not the engine overruns. When it is determined that the decision D6 is overrun, the process proceeds to process P7, the shift valve is controlled so as to shift the multi-stage gear speed change mechanism 20 to the second speed, and the process returns to process P2. If it is determined not to overrun, proceed to process P8 to prevent shift shock and
Shift to high speed and return to process P2.

On the other hand, if the shift range is not "1 range" in decision D3, the process proceeds to decision D9, and it is determined whether or not the shift range is "2 range". When the shift range is "2 range", the process proceeds to process P10 to release the lockup, and then the process P11 shifts to the second speed and returns to the process P2. Further, when it is determined in the decision D9 that the shift range is not “2 range”, and therefore the shift range is in the D range, the shift up control in the process P12, the shift down control in the process P13, and the process P14 are performed. Lock-up control is sequentially performed, and the process returns to the process P2.

Next, this shift-up control (process P1 in FIG. 5)
2) will be described in detail with reference to FIG.

First, the gear position, that is, the position of the multi-stage gear speed change mechanism 20 is read out. Next, based on this read gear position, the decision D21 is currently 4
It is determined whether or not it is fast. If it is not the fourth speed, the current throttle opening TH 'is read in process P22, and the shift-up map data (T _SP1 ) corresponding to the throttle opening TH' is read in process P23. An example of this shift-up map is shown in FIG. Next, in process P24, the current rotational speed of the output shaft 14 of the torque converter 10, that is, the turbine rotational speed Tsp ′ is read out, and this current turbine rotational speed T
sp ′ is compared with the shift-up map data Tsp ₁ read in the process P23, and at the decision D25, the current turbine speed Tsp ′ is related to the throttle opening TH ′ and the set turbine indicated on the shift line Mfu ₁ is shown. It is determined whether the rotation speed is higher than Tsp ₁ .

Then, the current turbine speed Tsp 'is, the throttle opening degree TH' when set greater than turbine speed Tsp ₁ in relation to, after reading the flag 1 for the first-stage shift-up in decision D26, this decision D26
It is determined whether the flag 1 read in step 1 is 0 or 1, that is, whether it is in the reset state or the set state. The flag 1 is changed from 0 to 1 when the 1-step shift-up is executed. When the flag 1 which stores the 1-step shift-up state is in the reset state, the flag 1 is set to 1 in the process P27, Then, in process P28, the gear is upshifted by one step to complete the upshift control.

On the other hand, if the flag 1 in the 1-stage shift-up control system is 1 in the decision D26, that is, the flag 1
When is in the set state, the control is completed as it is.

Also, in the first decision D21, when it is determined that the vehicle is in the 4th speed, the control is completed as it is. Further, in the decision D25, if it is determined that the current turbine speed Tsp ′ is not larger than the set turbine speed Tsp ₁ indicated by the shift line Mfu _{1 in} relation to the throttle opening TH, the setting is made in the process P30. Turbine speed Tsp ₁ ,
For example, it is multiplied by 0.8 to set a new set turbine rotational speed Tsp ₂ on the new shift line Mfu ₂ as shown by the broken line in FIG. 7. Next, at decision D31, it is judged whether or not the current turbine rotation speed Tsp ′ is larger than the set turbine rotation speed Tsp ₂ shown in the above-mentioned shift line Mfu ₂ , and Tsp ′ is used to determine Tsp ′.
_{If 2} is larger, the process P32 resets flag 1 to prepare for the next cycle, and conversely, Tsp ₂ rather than Tsp ₂
If is not larger, end the control as it is,
After this, shift down control is performed.

The downshift control is executed according to a downshift control subroutine as shown in FIG. This shift-down control is performed by first reading the gear position, as in the case of the shift-up control. Next, based on the read gear position, the decision D41 determines whether or not the present speed is the first speed. 1
When it is determined that the speed is high, the control is completed as it is. If it is not the first speed, the throttle opening TH 'is read in the process P42, and then the shift down map data (Tsp ₁ ) corresponding to the read throttle opening TH' is read in the process P43. An example of this shift down map is shown in FIG. Next, in process P44, the current turbine rotation speed Tsp ′ is read, and this turbine rotation speed Tsp ′ is collated with the set turbine rotation speed Tsp ₁ that is the data of the read shift down map to obtain the current turbine rotation speed Tsp ′. Is the shift down shift line Mf in relation to the throttle opening TH
The decision D45 determines whether the turbine speed is lower than the set turbine speed Tsp ₁ shown in d ₁ .

The current turbine speed Tsp ′ is the set turbine speed Tsp
_If it is smaller than _1, the flag D for downshifting one stage is read out at the decision D46. The flag 2 is changed from 0 to 1 when downshifting one step.

Next, it is determined whether this flag 2 is 0 or 1, that is, whether it is in the reset state or the set state. When flag 2 is in reset state, process P47
Then, the flag 2 is set to 1 and the downshift is performed in the process P48, and the downshift control is completed.

When the decision D46 determines that the flag 2 is in the set state, the downshift is impossible, so the control is completed as it is.

In addition, the current turbine speed T
When the sp 'is determined not to be smaller than the set turbine speed Tsp ₁ shown in downshift line Mfd ₁ is set turbine speed Tsp ₁ shown in process P49 to shift line Mfd ₁ of this map, for example, , 1 / 0.8 to set a new set turbine speed Tsp ₂ on the new shift line Mfd ₂ .
Next, at the decision D50, the current turbine speed Tsp ′
Is smaller than the set turbine speed Tsp ₂ indicated by the shift line Mfd ₂ , the control is completed as it is. On the other hand, if it is not smaller, the flag 2 is reset to 0 in process P51 to complete the control. After that, the control shifts to the lockup control.

In the above-described shift-up shift control and shift-down shift control, when no shift is performed, the shift line of the map is multiplied by 0.8 or 1 / 0.8 to form a new shift line to create hysteresis. This is to prevent chattering from occurring due to frequent gear shifting when the engine speed and turbine speed are at the critical speed of gear shifting.

Next, the lockup control will be described with reference to FIG.

First, in the lockup control, after the throttle opening TH ′ is read in the process P64, in the process P65, the shift line M used for the lockup release control using the lockup map as shown in FIG. Read the set turbine speed Tsp ₁ corresponding to the throttle opening TH obtained from _OFF . Next, in process P66, the current turbine speed Ts
p ′ is read out, and at the decision D67, this read out current turbine speed Tsp ′ is compared with the above lockup map, and this current turbine speed Tsp ′ is determined by the shift line M.
_It is determined whether or not it is higher than the set turbine speed Tsp ₁ indicated by _OFF . If the current turbine speed Tsp ′ is smaller than the set turbine speed Tsp ₁ , the process P68
The lockup is released with and the process ends.

On the other hand, when the current turbine rotation speed Tsp ′ is larger than the set turbine rotation speed Tsp _{1, the} shift line M used for the control for operating the lockup using the lockup map described above in process P69. Another set turbine speed T _SP2 corresponding to the throttle opening TH obtained from _ON (see Fig. 11) is read, and then the decision D70
And the current turbine speed Tsp ′ is the set turbine speed T
_It is determined whether it is greater than _SP2 . Where Tsp ′ is
If it is larger than T _SP2 , the lock-up operation is performed in the process P71, and the process ends. On the contrary, if Tsp ′ is not larger than T _SP2 , the process ends.

In the above lock-up control, when the shift-down signal Cp ′ is issued during the lock-up operation, the lock-up release signal Cq ′ is sent accordingly and is supplied to the fourth solenoid valve SL4 of the hydraulic control circuit CK. , The lock-up operation state is released, but the shift-down Cp 'is the first, second and third solenoid valves SL1, SL2 of the hydraulic control circuit CK.
And the supply to SL3 is delayed by the delay switch 8. The delay of the supply of the downshift signal Cp ′ to the first, second and third solenoid valves SL1, SL2 and SL3 with respect to the supply of the lockup release signal Cq ′ to the fourth solenoid valve SL4 and the subsequent delivery operation are It is executed according to the flow chart as shown in FIG.

In this flow, first in process P81, the content of process P48 in the flowchart of the downshift control described above with reference to FIG. 8 is read. Next, in the decision D82, it is determined whether or not the shift down should be performed in the process P48. Here, if it is determined that the shift down should not be performed, the process is ended as it is, and if it is determined that the shift down is to be performed, the process proceeds to a decision D83, and it is determined whether or not the lock-up operation state is established. . Decision D83
If it is determined that the lock-up operation is not being performed, the process proceeds to process P84, and the shift-down Cp ′ is set to the first, second and third solenoid valves SL1, SL2 and SL3 of the hydraulic control circuit CK.
To send to.

On the other hand, when the decision D83 determines that the lockup operation is being performed, the process proceeds to process P85, and the planned slip amount ΔTsp is calculated from the current turbine speed Tsp ′ and the throttle opening TH ′. The planned slip amount ΔTsp is calculated according to the characteristics of the torque converter 10 as described above, and for example, ΔTsp = k · TH ′ / Tsp ′ where k is a constant.
In this example, in particular, the sliding amount when the lockup clutch 15 is completely released from the lockup operation state, that is, the output shaft 1 of the engine EN and the torque converter 10 when the lockup release is completed. Output shaft 14
(The output shaft of the turbine 12) and the rotational speed difference.

Next, in process P86, the slip amount ΔTsp calculated in process P85 described above is multiplied by α (a constant) to compensate for the response delay of the hydraulic system of the hydraulic control circuit CK to calculate the theoretical slip amount ΔTspc, and then, Proceeding to process P87, the lockup release signal Cq 'is sent to the fourth solenoid valve SL4 of the hydraulic control circuit CK.
To process P88.

In process P88, the actual amount of slip ΔTspr is calculated from the current engine speed Esp ′ and the turbine speed Tsp ′, and the process proceeds to decision D89. The actual amount of slip ΔTspr calculated in process P88 is calculated in process P86. It is determined whether or not the theoretical slip amount is ΔTspc or more. As a result of this determination, if the actual amount of slip ΔTspr is not equal to or larger than the theoretical amount of slip ΔTspc, the process returns to process P88. Conversely, if the actual amount of slip ΔTspr is equal to or larger than the amount of theoretical slip ΔTspc, the process P8
4, the rotation speed difference signal Sd is generated, and the downshift control signal Cp ′ is sent to be supplied to the first, second and third solenoid valves SL1, SL2 and SL3 of the hydraulic control circuit CK. To finish.

(Effects of the Invention) As is apparent from the above description, the control device for an automatic transmission according to the present invention is a lockup provided between an output shaft of an engine and an output shaft of a torque converter connected thereto. The mechanism is set to an operating state that locks up the output shaft of the engine and the output shaft of the torque converter according to the vehicle speed, etc., and the operating state of the lockup mechanism is temporarily released during shift control, and further downshifting is performed. At the time of control, when performing the downshift after the lockup release signal is sent from the lockup control means to the lockup electromagnetic means, the difference between the output shaft speed of the engine and the output shaft speed of the torque converter is It is possible to supply the shift-down signal from the shift control means to the shift-changing electromagnetic means at an appropriate time when it is opened and is equal to or more than a predetermined value. As a result, it is possible to effectively suppress the occurrence of shock associated with the shift-down control and prevent the shift-down timing from being delayed more than necessary.

[Brief description of drawings]

FIG. 1 is a block diagram showing a mechanical main part of an example of an automatic transmission to which an example of a control device for an automatic transmission according to the present invention is applied and a hydraulic control circuit accompanying the mechanical main part, and FIG. An example of a control device for such an automatic transmission is shown with an automatic transmission and an engine to which the control device is applied, and FIGS. 3 and 4 are characteristic diagrams used to explain the operation of the example shown in FIG. 5, FIG. 6, FIG. 8, FIG. 10, FIG. 10 and FIG. 12 are flowcharts showing an example of an operation program of a microcomputer constituting an example of a control unit used in the example shown in FIG. FIG. 9, FIG. 9 and FIG. 11 are characteristic diagrams provided for explaining the operation according to the flowcharts of FIG. 6, FIG. 8 and FIG. 10, respectively. In the figure, 5 is a lockup control circuit, 6 is a shift control circuit,
7 is a rotational speed difference detection circuit, 8 is a delay switch, 10 is a torque converter, 20 is a multi-stage gear transmission mechanism, 200 is a control unit, AT is an automatic transmission, CK is a hydraulic control circuit, EN is an engine, TS is a turbine rotation. Number sensor, ES is engine speed sensor, LS is engine load sensor, SL1 to SL4 are first to fourth
It is a solenoid valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Kikuchi 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-57-76359 (JP, A) JP-A-58- 214060 (JP, A)

Claims (1)

[Claims] 1. A lockup mechanism for selectively locking up an output shaft of an engine and an output shaft of a torque converter that is driven by being connected to the output shaft of the engine; and a lockup mechanism connected to the output shaft of the torque converter. A hydraulic control circuit having a speed change electromagnetic means for switching the power transmission path of the speed change gear mechanism, and a lockup electromagnetic means for making the lockup mechanism in an operating state or a released state, and a load of the engine or of the engine. An engine load sensor that detects information corresponding to the load, information that corresponds to the output shaft speed of the engine or the output shaft speed of the engine, and the output shaft speed of the torque converter or the output shaft speed of the torque converter. From a speed sensor that detects information corresponding to the engine load sensor and the speed sensor On the basis of the signal obtained, on the basis of the signal obtained from the engine load sensor and the speed sensor, the gear shift control means for sending out the shift up signal or the shift down signal to the gear position switching electromagnetic means, The lockup control means for sending a lockup operation signal or a lockup release signal to the lockup electromagnetic means, and the difference between the output shaft speed of the engine and the output shaft speed of the torque converter are obtained, When the shift-down signal is transmitted from the shift control means together with the transmission of the lock-up release signal from the lock-up control means, the shift of the shift-down signal is changed until the obtained difference becomes a predetermined value or more. A control device for an automatic transmission, comprising: delaying means for delaying supply to the electromagnetic means for gear change.