JPS6014653A - Slip controlling apparatus in torque converter - Google Patents

Abstract

PURPOSE:To prevent generation of speed-change shock by keeping a slip control means into a prescribed constant state for a prescribed time after the speed- change instruction for a gear speed change mechanism is transmitted. CONSTITUTION:A calculation stop means (g) is connected to a slip control means (e), and after speed change instruction for a gear speed change mechanism is transmitted, the slip control means (e) is kept in the state immediately before speed change instruction or a prescribed constant state during the prescribed time corresponding to the time lag. Therefore, a torque converter develops the torque variation absorbing performance for a prescribed time. Therefore, the generation of speed change shock due to the wrong understanding for the actual slip amount is prevented during the time lag.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a torque converter used in a power transmission system of an automatic transmission, and particularly to a lock-up torque converter no-slip control device.

Automatic transmissions are typically configured to transmit power from a prime mover to a gear transmission via a torque converter, and automatically shift the power by this mechanism.

By the way, a normal torque converter converts the output element (usually a turbine runner) through working fluid stirred by an input element (usually a pump impeller) driven by a prime mover.
Since power is transmitted by driving the motor, a torque increasing function and a torque fluctuation absorbing function can be obtained, but on the other hand, relative rotation (slip of the torque converter) between input and output elements cannot be avoided, resulting in poor power transmission efficiency. Therefore, a lock-up torque converter has been put into practical use that improves power transmission efficiency by limiting the above-mentioned slip to the minimum necessary level that meets the requirements for torque increase function and torque fluctuation absorption function as appropriate depending on the operating state of the prime mover. It's starting to sushi.

This lock-up torque converter is constructed by adding a lock-up clutch to an ordinary torque converter to mechanically directly connect its input/output elements or to appropriately reduce this direct connection. When the lock-up clutch is fully engaged, the torque converter is made to function in the so-called converter state 9 when the lock-up clutch is released, and when the lock-up clutch is fully engaged, the torque converter is made to function in the so-called lock-up state where no slip occurs, and when the lock-up clutch's coupling force is controlled, the torque converter is It can function in a so-called slip control state in which slip is limited to a target slip amount.

The slip control device that brings the actual slip amount to the target slip amount when the torque converter functions under slip control generally performs calculations based on the error of the actual slip amount with respect to the target slip amount, and uses the calculation result to determine the slip amount. It is common practice to adjust the coupling force of the lock-up clutch so that the lock-up clutch is eliminated.

However, in such a slip control device, it is not possible to directly measure the rotation speed of the output element that should be detected when calculating the actual slip amount due to the configuration of the torque converter. It is customary to determine the rotational speed of the output element by calculating both. In this case, the rotation speed of the output element determined by the above calculation will be explained when shifting from 2 to 8 gears. As shown in Fig. 15, the gear shift signal of the gear transmission mechanism switches from the 2nd gear to the 8th gear (the shift pulp is (Switching) The output rotation speed N of the gear transmission mechanism at □ just before the speed change command. (However, when the gear ratio of the third speed is 1), it is calculated as the value NT'.

However, the gear transmission mechanism can perform a speed change immediately upon switching of the shift pulp, but due to the response delay of the shift control hydraulic system, the actual speed change cannot be performed until after a time lag shown by ΔT in FIG. 5.

Therefore, the prime mover rotation speed (input element rotation speed) NE decreases with a delay from the instant t□ according to the time lag ΔT, and the actual rotation speed tends to be kept lower by the target slip amount ΔNo than this rotation ′fiNg (by slip control). The output element rotational speed NT also decreases with a delay after the instant t0.

Therefore, during the time lag 47, the output element rotation speed NT' determined by the calculation deviates from the actual output element rotation speed NT, and the actual slip is assumed to be ΔN2 when it is actually ΔN1, and the target slip amount is assumed to be ΔN2. In this case, the slip control device temporarily increases the calculation result in the lock-up direction as shown in FIG. This causes the data to become almost locked up.

In this case, the gear transmission mechanism changes gears with the torque converter almost in a locked-up state, and the torque converter's ability to absorb torque fluctuations cannot be obtained.
As shown in FIG. 15, the torque waveform has a large peak torque Try + TrZ, which causes a large shift shock. The purpose of this invention is to maintain the device in a state immediately before a speed change command or in a predetermined constant state to prevent the occurrence of a speed change shock caused by a misjudgment of the output element rotation speed.

For this purpose, the torque converter overnight slip control device of the present invention has a transmission path that transmits power from a prime mover a to an output shaft c via a torque converter b, as shown in FIG.
A lock-up torque converter is provided, which also has a transmission path for directly transmitting the power to the output shaft C via a link-up clutch d, which is connected as appropriate. An automatic transmission comprising a slip control means e that controls the coupling force of the lock amplifier clutch d so as to eliminate the error based on a calculation result based on the error of the actual slip amount, and a gear transmission mechanism f that automatically changes the rotation of the output shaft C. The apparatus is characterized in that it is provided with calculation stop means g for maintaining the slip control means e in the state immediately before the shift command or in a predetermined constant state for a predetermined period of time after the shift command of the gear transmission @f.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 2 shows an embodiment of the present invention, in which 1 is an engine as a prime mover, 2 is a crankshaft thereof, 8 is a flywheel, 4 is a lock-up torque converter, and 5 is a dual transmission mechanism. The torque converter 4 includes a pump impeller (input element) which is connected to the crankshaft 2 via a flywheel 8 and is constantly driven by the engine + a turbine runner 4b (output element) disposed opposite thereto, and a stator (reaction force controller). The turbine runner 4b is drivingly connected to the input shaft (torque converter output shaft) 1 of the transmission fl15, and the stator 4C is placed on the hollow fixed shaft 9 via the one-way clutch 8.

A working fluid is supplied to the internal converter chamber 10 of the torque converter 4 in the direction of arrow A, and this working fluid is removed in the direction of arrow B, and a pressure retaining valve (not shown) provided in the middle thereof.
The inside of the converter chamber 10 is maintained at a pressure (converter pressure) Po below the value. Thus, as described above, the engine-driven pump impeller 4Ia stirs the internal working fluid,
After colliding with the turbine runner 4b, the stator 4
During this period, the turbine runner 4Ib is rotated while increasing the torque under the reaction force of the stator 4C.

This rotation is input to the gear transmission mechanism 5 via the shaft 7, where it is automatically shifted to a suitable rotation speed and output from the shaft 5a.

In addition, in order to be able to limit slip (relative rotation between the input element 41a and the output cylinder 1b), the torque converter 4
A lock-up clutch [1 is provided, which is movable in the axial direction on a shaft 7 via a torsional damper 12 and is drivingly connected. Thus, the four-up clutch 11 sets the lock amplifier chamber 18 in the converter chamber lO, and the converter pressure P in the chamber 10 and the lock-up pressure PL/u in the chamber 18
The input/output element 4 responds to the differential pressure between the
Torque converter 4 is mechanically coupled to drive between a and +b.
dLockup pressure P that can limit the slip of
L/u is adjusted by the slimp flrl valve t 41 d, but this valve is connected to the boat [4a
The converter pressure P. 14. b
and a drain boat 141c, and when the spool 14d is in the neutral position shown, the boat 1Φa is connected to both boats 14b and 1.
When the spool 14d moves to the right in the figure, the boat 14a is connected to the boat 14b, and when the spool 14d moves to the left in the figure, the boat 14a is connected to the boat 140. And spool L4d is orifice 1
5, the lock amplifier pressure that acts on the right end surface in the figure "L/
The control pressure Ps is created in the following manner in response to the differential pressure between the control pressure Ps and the control pressure Ps acting on the left end surface in the figure. That is, the reference pressure (line pressure in the case of an automatic transmission) which controls the speed change of the transmission mechanism 5 is supplied from one end i6a of the control pressure generation circuit 16, and this line pressure is supplied to the other end of the circuit 16 through the orifice 17, 18. By draining from 16b and determining the amount of draining by a duty-controlled electromagnetic valve 19, a control EEP8 can be created between 17 and 18.

In normal state, the solenoid valve 19 is closed to the plunger 19 by the spring 19a.
By moving b to the left in the figure, the drain>U of the circuit 16
116b, and each time the solenoid 19c is energized, the plunger L9b is moved to the rightward position as shown in the figure to open the drain opening end 16b and allow the above-mentioned drain. The solenoid 190 is energized from the slip control computer 20 as shown in FIGS. 3(a) and 8(b).
The duty control is performed so that it is performed during the pulse width (on time) of the pulse signal as shown in FIG. Figure 8 (a
) When the duty (%) is small, the solenoid valve 19
The time during which the drain opening end 16b is opened is short, so the control pressure PS is equal to the line pressure P as shown in FIG. or,
As the duty (%) increases as shown in ) in FIG. 8, the solenoid valve 19 begins to open the drain opening end 16b for a long time, so the control pressure PB gradually decreases as shown in FIG. 4, and finally It is a constant value determined by the difference in the opening area of the orifices 17 and 18.

In FIG. 1, as the control pressure P8 increases,
) fit [I For stretching, move the spool t4d to Fig. 5 (a)
14a to the boat 14b gradually increasing the lock amplifier pressure "L/u" to P:c,
With the relationship 7u = kP8 (k is a constant), the sixth
As shown in the figure, the converter pressure gradually increases and finally the converter pressure P. A constant value corresponding to Then, as the control pressure P8 becomes lower, the lock-up pressure P L/u on the end face of the spool r4d on the opposite side to where it acts causes the spool 14d to move to the left as shown in FIG.
c, and the lock-up pressure PL/u is gradually decreased in the same manner as above, and finally reaches zero. The slip control valve 14 has a lock-up pressure "L/u" which is the control pressure P.
When the value corresponding to s is reached, the spool 14d is returned to the neutral position shown in FIG. can.

By the way, the control pressure P with respect to the duty (%)
The change characteristics of s are as shown in FIG. 4, and from this and the control pressure (Ps)-lockup pressure (PL/u) characteristics shown in FIG.
The change characteristics of /u are as shown in FIG.

The slip control computer 20 is operated by the power supply +■, and detects the gear position signal Sg from the gear position sensor 6, which detects the gear position depending on the position of the automatic transmission shift valve (return 5), and the engine rotation. Signal 5ir from the number sensor 21 regarding the engine rotation speed (rotation speed of the input row 1a) 1 Signal S.r from the output rotation speed sensor 22 regarding the output rotation speed of the pawl transmission mechanism and engine throttle opening/opening from the throttle opening sensor 28 The signals S and H related to this are calculated, and the solenoid valve 19 is duty-controlled as described below based on the calculation results.

The computer 20 includes, for example, a microprocessor unit (MPU) 24 including a random access memory (RAM) and a read only memory (ROM), as shown in FIG.
25, and input/output interface circuit (Ilo), 26
It is assumed that the microcomputer consists of an analog-to-digital converter (A/D) 27, a waveform shaping circuit 28, and an amplifier 29, and executes the control programs shown in FIGS. 9 to 12.

FIG. 9 shows the main routine, and when the ignition switch of the engine 1 is turned on at step 30, the computer 2o starts operating, and the next step 7F! 31
rMPU24 and H1026(7)'' Initial value setting (initialization) is performed. Next, the control proceeds to step 82, where the PH10 reads the gear position signal S9 from the sensor 6 via the Ilo 26, and converts the throttle opening signal STH from the sensor 28 into digital data using the A/D converter 27. The bales converted into signals (however, in this example, the digital signal is quantized by dividing the period from fully closed to fully open throttle into 8 parts) are read through Ilo 26.

The control then proceeds to step 88, where the MPU 24 executes the interrupt routine shown in FIG. 10(a) based on the signal sir from the engine speed sensor 21 to calculate the engine speed -. The sensor 21 detects the ignition signal of the engine 1 and emits a signal Sir as shown in FIG. A rectangular wave signal Sir' rises every time the signal is input. Then, the MPU 24 starts the interrupt routine shown in FIG. 10(a) every time the signal si□ rises. First, in step 410, the rising edge of the signal sir' is read through Ilo 26, and then in the next step 41
The signal period T□ is measured from the time whistle with the rise of the previous signal "'ir," and the MPU 24 can calculate the engine rotational speeds N and E from this period T□.Then, the control proceeds to step 412. At this point, the process returns to the main routine shown in FIG.

In the next step 34 in FIG. 9, the MPU 24 receives the signal S from the output rotation speed sensor 22. Based on r, the interrupt routine shown in FIG. 11(a) is executed as follows to calculate the output rotational speed No. of the transmission mechanism 5. The sensor 22 is, for example, the input shaft 5
The signal S shown in FIG. 11 Φ) is attached to a and during its rotation.

A sine waveform generator outputting a signal r is used, and each time the amplitude of the signal exceeds a threshold level, the waveform shaper 28 is triggered and the waveform shaper generates a rectangular wave signal S shown in FIG. 1(b). r'. Then, the MPU 24 sends the signal S
. The interrupt routine shown in FIG. 11(a) is started every time r' rises, and first, in step 50, the signal S is output. r' as Ilo
26, and the previous signal S is read in the next step 51.

The signal period T2 is measured from the time difference with r', and the MPU 24
I is the output rotation speed N of the southeast transmission 15 based on this cycle. can be calculated. Control then proceeds to step 52, where it returns to the main routine of FIG.

In the next step 85 in FIG. 9, it is determined from the gear position signal S9 read in step 32 whether the gear transmission mechanism 6 is in the rotation gear position, and in step 86, this gear position is the previous determined gear position. It is determined whether or not the gear transmission mechanism 6 is changing gears based on whether or not the difference is different. If a gear shift is being performed, control proceeds to step 87, where timer t
is cleared to 0, the timer t is operated by the reference clock of the microcomputer, and the time from the start of gear shifting can be measured. Control then proceeds to step 38;
Here, by comparing the previous determined gear position and the current determined gear position, it is determined which type of gear change the southeast transmission vi5 is performing, that is, the type of gear change.

Next, control proceeds to step 89, where a predetermined time TMc corresponding to the time lag ΔT (see FIG. 15) is set. By the way, since the time lag ΔT varies depending on the load of the engine l (throttle opening degree) and the type of gear change, the MPU 241 changes depending on the throttle opening degree and the type of gear change as shown in the table below regarding the predetermined time stored in advance in the ROM 25. MPU24 is ROM
Table 0 shows the predetermined time TIC stored in advance in step 25. In the next step 48, it is determined whether the timer t started operating in step 87 is longer than the predetermined time TMo set in step 89. In other words, it is determined whether a predetermined time TMo has elapsed since the start of the gear shift, and if not, the flag FLG is set to 1 in step 44, and if so, the flag FLG is reset to 0 in step 45. Control continues to step 416. In step 46, step 84
．． ? The output rotation N of the gear transmission groove 5 obtained in step 85. The rotation speed of the shaft 7, that is, the rotation speed NT of the turbine launch 4b is calculated from the gear position (speed ratio). Next Stella -7
'47r The MPU 24 reads a table corresponding to the diagram shown in FIG. 18 from the ROM 25, and based on this table, calculates the target slip fit Ns corresponding to the throttle opening degree and the engine speed NE using the table lookup method and sets it to the 121J. The interrupt routine shown is executed to perform slip control on the torque converter 4 as described below.

FIG. 18 shows the target slip amount of the torque converter 4 to be achieved for each operating state of the engine l represented by the throttle opening degree and the engine speed. is the pull-up state, and the numerical value in the figure is the target slip amount in the slip control state.

By the way, if it is determined in step 86 that the gear transmission mechanism 5 is not changing gears, the control proceeds to step 86.
The process then proceeds to step 4+8, where it is determined whether or not the 1i'LG is O, that is, whether a predetermined time TMo has elapsed since the start of gear shift fltm5, and if so, in step 419, a predetermined The time is rewritten to T14ot-O, and if not, that is, if the predetermined time TMo has not elapsed since the start of the shift, the control proceeds sequentially to steps 7 48 to 47. Note that after step 47, the process returns to step 82.
Thereafter, the above-described control is repeatedly executed.

Next, the interrupt routine shown in FIG. 12 will be explained. This routine is started by an interrupt signal input from the timer at regular time intervals Sms. First, in step 70, it is determined whether the flag FLG is 0 or not, that is, whether or not a predetermined time TMc has elapsed since the start of high speed, as is clear from the above, and if so, step 71
At this point, it is determined whether or not the operating state of the engine 1 is in the complete I, /u range from the corresponding address in the table shown in FIG. 13 based on the throttle opening degree and the engine speed NE. If it is not in the complete L/U range, step 72 is selected, and a similar table lookup method is used to determine whether or not the operating state of the engine 1 is in the complete A/T range. If it is not the 'I' region, control proceeds to step 7B. In this step 78, the engine rotation speed (the rotation speed of the input element 4a) No. and the shaft 7
The rotational speed (rotational speed of the output element 4b) NT is used to calculate the rotational difference between the two (actual slip of the torque converter 4) The slip error ΔN of
Calculate by =X-N8. Next, the control proceeds to step 75, where it is determined whether the slip error ΔN is larger than O, that is, whether the actual slip amount X is larger than the target slip amount Ns and the torque converter 4 is slipping too much than the target. . If so, in step 76, Dut'
y (NEW) = Duty (OLD) + k・ΔN (however, k
calculates the proportional constant 9 in the direction of increasing the output duty, and uses the calculation result Duty (NEW) in the next step 7.
7 After replacing Duty (OLD), step 7
Set Duty (NEW) to the output duty at B. This output duty is supplied to the solenoid 190 of the electromagnetic valve 19 through the amplifier 29 in FIG. As is clear from Fig. 7, in order to increase the lock-up pressure PL/u, the lock-up pressure PL/u is sequentially lowered each time the control is repeated as long as ΔN≧0.Therefore, the lock-up clutch 11 in Fig. The drive coupling between elements 4a and 4b is strengthened, the torque converter 4 is corrected for the above-mentioned excessive slip, and the slip amount X is changed to the target slip amount N.
You can bring it to 8.

On the other hand, if the determination result in step '15 is ΔN(0, that is, if the torque converter 4 is insufficient for the target x lip amount N8, step 75 selects step 79, and in step 79, Duty (OLD) -k・ΔN (where k is a proportionality constant) in the direction of decreasing the output duty, and the calculation result Dut'/(NEW) is replaced with Duty (OLD) in the next step 77, and then in step 78 Dut3' (NEW) is set as the output duty.In this case, the output duty of the solenoid valve 19 controlled by the output duty is reduced by an amount proportional to the constant k according to the slip error ΔN, so that the lock-up EPL/ As is clear from Fig. 7, u is ΔN(0
As long as Therefore, the lock-up clutch 11 weakens the drive coupling between the torque converter input/output elements 4a and 4b, and the torque converter 4 is corrected for the above-mentioned lack of slip, and its slip amount
can be brought to the target slip amount N8.

By the way, if the determination result in step 7■ is in the complete L/u region, this step selects step 80, sets the output duty to the maximum of 100%, and supplies this to the solenoid valve lenoid 190 via the amplifier 29. . At this time, the lock-up pressure PL/u is set to the minimum value as shown in FIG.
It is possible to create a lock-up state in which the parts a' and 4b are completely connected by the lock-up clutch 11. If it is determined in step 72 that it is a complete A/T region, this step selects step 81 and sets the output duty to the lowest 0%. At this time, the lock-up pressure PL/u is 7th.
As is clear from the figure, converter pressure P. As a result, the lock-up clutch 11 is disengaged and the torque converter 4 can be brought into the converter state as requested.

Step 78. ．． After completion of step 80 or 81, control proceeds to step 82, where the main routine of FIG. 9 is returned to,
As the control returns from step 47 to step 82, the above program is repeatedly executed.
It is possible to operate the converter in a converter state, a lock-up state, or in a state in which the actual slip amount is set to the target slip amount as required depending on the operating condition of the engine I.

Note that if it is determined in step 70 that the flag FLG is 1, that is, if the predetermined time TMo has not yet elapsed since the start of the shift, the control proceeds from step 70 to step 8.
Proceed to step 8. In this step, the previous output duty is 10.
It is determined whether or not it is 0%, that is, whether or not the torque converter 4 is in a four-up state. If so, the output duty is set to 0% in step 81, and if not, the control proceeds from step 83 to step 82 and the previous output duty is maintained as is.

The above control related to the apparatus of the present invention is summarized as follows. For example, following the example in Figure 15,
As shown in the figure, the shift signal switches from the 2nd speed signal to the 8th speed signal at the instant t, and the 2->8 shift starts, and the shift is completed at the instant t2 after the tie-up ΔT. Engine rotation speed - and gear transmission mechanism output rotation speed N. To explain the case where the flag FLG changes as shown in the figure, the flag FLG is set to 1 for a predetermined time TMc corresponding to the time lag ΔT from the instant t when the gear shift is started. If the torque converter 4 is not in a lock-up state at the second speed, the output duty is maintained at the duty ratio immediately before starting the TMoMo intermediate speed for a predetermined period of time.
If the torque converter 4 is in the slip control state at the second speed, the output duty can be maintained as shown by TMoMo 14D□ for a predetermined period of time, and if the torque converter 4 is in the converter state at the second speed. Then, the output duty can be maintained at 0% during the predetermined time TMc. Therefore, as described above with reference to FIG. 15, slip control proceeds despite the fact that the actual slip amount is incorrectly determined during the time lag ΔT, and the actual slip amount at instant t is maintained with the torque converter 4 almost in the lock-up state. It is possible to prevent gear shifting from being performed. Therefore, the torque converter 4 can perform a predetermined torque fluctuation absorbing function during this period, and can sufficiently absorb the shock caused by shifting, and the torque waveform is as shown in FIG.
r2 It is possible to minimize the occurrence of shift shock. Note that if the torque converter 4 is in the lock-up state in the second gear, and the output duty is held as described above, the gear shift will be performed while the torque converter damage remains in the lock-up state. 81 to 0%, and this output duty of 0% is maintained for a predetermined time TM as shown by D in FIG.

Try to hold it inside. As a result, the torque converter 4
is maintained in the converter state until the shift is completed, and the occurrence of shift shock can be similarly prevented.

Thus, as described above, the slip control device of the present invention maintains the slip control device in the state immediately before the shift command (i.e.,
The time lag Δ
It is possible to prevent the occurrence of a shift shock due to a misjudgment of the actual slip amount during T-shifting, as described in the summary above, and the commercial value of the automatic transmission can be greatly increased.

[Brief Description of the Drawings] Fig. 1 is a conceptual diagram of the slip control device of the present invention, Fig. 2 is a system diagram showing an embodiment of the device of the present invention together with the power transmission system of an automatic transmission, and Fig. 8 (a) FIG. 4 is a time chart showing the output duty of the slip control computer in two types of change situations, FIG. 4 is a change characteristic diagram of the control pressure with respect to the output duty, FIG. b) is an explanatory diagram of the operation of the slip control valve, Figure 6 is a diagram of the change in lock-up pressure with respect to control pressure, Figure 7 is a diagram of change in lock-up pressure with respect to duty, and Figure 8 is a block diagram of the computer for slip control. 9, fig L0(a), FIG. 11(a) and FIG. 12 are flowcharts showing the control program of the computer for slip control, FIG. 1θ(b) and FIG. 11(b), respectively. are waveform explanatory diagrams of the engine rotation i signal and the transmission mechanism output rotation speed signal, respectively;
Fig. 8 is a torque converter target slip amount diagram, Fig. 14 is an operation time chart of slip control by the device of the present invention, and Fig. 15 is an operation of slip control by the conventional device! ...This is a time chart. 1... Engine (prime mover a), 2... Crankshaft 4... Torque converter (b) 5... Gear transmission mechanism (f) 6... Gear position sensor 7... Torque converter output I+h (c)10
Converter chamber 11 Lock-up clutch (d) 18 Lock-up chamber 14+ Slip control valve 16 Control pressure generation circuit L9 Solenoid valve 190 Solenoid 20 ... Slip control computer 21 ... Engine speed sensor 22 ... Gear shift l! ll Purchasing power rotation speed 28...Engine throttle opening sensor 24...Microprocessor unit (MPU) 25°, read-only memory (R
OM)26...Input/output interface circuit (Il
o) 27...A/D converter 28...Waveform shaping circuit 29...Amplifier e...Slip control means...
Calculation stop means. Fig. 3 Fig. 4 SoL Noid Mete 1-; Wow (%n Fig. 5 ca) (b) Fig. 6 Fig. 7

Claims (1)

[Scope of Claims] L A lock that has both a transmission path that transmits power from a prime mover to an output shaft via a torque converter and a transmission path that directly transmits the power to the output shaft via a lock-up clutch that is appropriately coupled. a slip control means for controlling the coupling force of the lock amplifier clutch so as to eliminate the error based on a calculation result that reveals an error between the actual slip amount and the target slip amount of the lock up torque converter; In an automatic transmission having a two-way speed change mechanism that automatically changes rotation, the method further comprises: a computation stopping means for holding the slip control means in a state immediately before the speed change command or in a predetermined constant state for a predetermined period of time after a speed change command of the southeast speed change mechanism is provided. A torque converter slip control device characterized by: 2. The slip control device for a torque converter according to claim 1, wherein the calculation stop means changes the suspended time depending on the load of the prime mover, the type of the shift command, or both.