JP5217565B2 - Control device for automatic transmission - Google Patents

Description

  The present invention relates to a control device for an automatic transmission in which a frictional engagement element slips in order to absorb torque fluctuation during acceleration / deceleration.

  In a control device for an automatic transmission equipped with a fluid transmission device with a lock-up clutch (explained in the case of a torque converter), a control region for the lock-up clutch is set in accordance with the vehicle running state such as engine load and vehicle speed. Various devices that control the lock-up clutch in various control areas are known.

  For example, three control areas, lockup, converter, and slip, are set. In the lockup area, the torque converter is turned on to improve fuel efficiency, and the output side is directly connected (lockup). Disconnect the output side (lock-up off).

  In the slip region, the input and output sides are slipped in a semi-fastened state to absorb engine torque fluctuations.

  However, since the lock-up clutch has a large diameter, a volume of the hydraulic chamber, and a mass of the piston, the response to the hydraulic pressure is poor and the accuracy of the slip control is difficult.

  On the other hand, as shown in Patent Document 1, instead of the lock-up clutch, among the plurality of frictional engagement elements constituting the transmission mechanism, a frictional engagement element forming a gear stage (hereinafter, for convenience of explanation) A technique for slipping a shift clutch) has been proposed.

This shift clutch is smaller and more responsive than the lock-up clutch, and has excellent slip control accuracy.
JP 2007-225048 A

  However, in the known technology for slip control of a shift clutch, at the time of slip control, one of a plurality of shift clutches forming the gear stage at that time is specified in advance as a slip target, and only this specific shift clutch is slipped. The structure to make it take is taken.

  For this reason, there has been a problem that the damage (wear, etc.) of the shift clutch to be slipped becomes larger than that of other shift clutches, and the durability is lowered.

  In the above known technique, the target slip amount is reduced when the facing temperature is equal to or higher than a predetermined value in order to suppress damage to the slip clutch to be slipped. However, when this is done, the inherent torque fluctuation absorbing capability of the slip control is lowered.

  Accordingly, the present invention provides a control device for an automatic transmission that can improve the durability by suppressing damage to a shift clutch (friction engagement element) to be slipped while maintaining the torque fluctuation absorbing capability. .

The invention according to claim 1 includes first and second frictional engagement elements that are fastened to form a predetermined shift speed, and slip control means that controls the frictional engagement elements to a predetermined target slip amount during non-shifting. The control device for an automatic transmission, wherein the slip control means slips the first frictional engagement element while completely engaging the second frictional engagement element, and slips the second frictional engagement element. The second control for completely fastening the first frictional engagement element is configured to be used properly while maintaining a predetermined shift speed based on a predetermined use condition.

  According to a second aspect of the present invention, in the configuration of the first aspect, when the slip control means starts the slip control, the one having the lower facing temperature of the frictional engagement element to be slipped of the first and second controls is the lower It is configured to be selected and executed as being suitable for use conditions.

  According to a third aspect of the present invention, in the configuration of the first or second aspect, the slip control means is configured such that the facing temperature of the frictional engagement element during the slip is not less than a set value during the execution of the first control or the second control. When it becomes, it is configured to switch to the other control because it does not conform to the use conditions.

  According to a fourth aspect of the present invention, in the configuration of the third aspect, the slip control means increases a fastening capacity of the switching friction engagement element and a fastening of the switching friction engagement element in a transition period of control switching. In accordance with the increase in the capacity, the engagement capacity of the friction engagement element at the switching destination is decreased.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the fluid transmission device with a lock-up clutch is provided, and the slip control means is used by both the first and second frictional engagement elements. When the condition is not met, the first or second control is switched to the third control for slipping the lockup clutch.

  According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the slip control means increases a fastening capacity of the frictional engagement element as a switching source in a transition period of switching from the first control or the second control to the third control. On the other hand, the engagement capacity of the lock-up clutch is decreased in response to an increase in the engagement capacity of the switching-source frictional engagement element.

According to the present invention, at the time of slip control, the first control for slipping the first frictional engagement element among the frictional engagement elements (transmission clutch) forming the shift stage and completely engaging the second frictional engagement element, and the second friction engagement The second control in which the first friction engagement element is completely engaged while the element is slipped is used under the conditions of use (for example, the one having the lower facing temperature of the friction engagement element to be slipped at the start of control as in the invention of claim 2) ), While maintaining a predetermined gear position, while maintaining the torque fluctuation absorption capability, which is the original purpose of slip control, suppresses damage to the frictional engagement element compared to slipping only a specific frictional engagement element. , Its durability can be improved.

  In this case, since the increase in the facing temperature causes damage to the frictional engagement element, the control is executed from the lower facing temperature of the frictional engagement element to be slipped at the start of the control. It is highly effective in improving the durability of the element.

  Further, as in the third and fourth aspects of the invention, when the facing temperature of the frictional engagement element during the slip becomes equal to or higher than the set value during the slip control (the first control or the second control), the use condition Since the control is switched from the first control to the second control or vice versa as it does not conform to the above, the effect of suppressing the damage of the frictional engagement element is further enhanced.

  In this case, according to the invention of claim 4, the fastening capacity of the friction fastening element of the switching destination is correspondingly increased while the fastening capacity of the friction fastening element of the switching source (during slip) is increased in the transition period of the switching. Therefore, the control can be smoothly switched while ensuring the target slip amount.

  On the other hand, according to the inventions of claims 5 and 6, when neither of the first and second frictional engagement elements meet the use conditions (for example, the facing temperature exceeds a set value), the lockup clutch is used as an alternative. Therefore, the intended purpose of improving the durability of the frictional engagement element can be effectively achieved.

  In this case, according to the invention of claim 6, as in the invention of claim 4, the slip object can be smoothly switched from the frictional engagement element to the lock-up clutch while ensuring the target slip amount.

1st Embodiment (refer FIGS. 1-6)
First, the entire configuration of an automatic transmission that is an application target will be briefly described with reference to FIG. 1 (skeleton diagram).

  The automatic transmission includes, as main components, a torque converter 2 as a fluid transmission device attached to the engine output shaft 1, and a transmission mechanism 4 to which output rotation of the torque converter 2 is input via an input shaft 3. The output rotation of the speed change mechanism 4 is transmitted from the output gear 5 arranged around the input shaft 3 to the axle via a counter driver mechanism and a differential device (not shown). Reference numeral 6 denotes a transmission case in which the transmission mechanism 4 is accommodated.

  The fluid transmission device is not limited to the torque converter 2 and may be a fluid coupling. The automatic transmission to which the present invention is applied is not limited to the stepped transmission illustrated below, but CVT (Continuosly Variable Transmission) that changes the gear ratio steplessly or dual clutch DSG (Direct -Shift Gearbox).

  The torque converter 2 includes a case 2a connected to the engine output shaft 1, a pump 2b provided in the case 2a, a turbine 2c driven by the pump 2b, and torque between the pump 2b and the turbine 2c. A stator 2d that performs an increasing action, a torque converter one-way clutch 2e provided between the stator 2d and the transmission case 6, and a lock-up clutch 2f that directly connects the engine output shaft 1 and the turbine 2c via the case 2a. The rotation of the turbine 2 c is transmitted to the transmission mechanism 4 via the input shaft 3.

  The lock-up clutch 2f is a hydraulic clutch that is operated by hydraulic pressure from an engine-driven hydraulic pump (not shown), and is configured as a pressure-off type clutch that is in a lock-up state when depressurized and in a lock-up off state when pressurized. Has been.

  The transmission mechanism 4 includes first, second, and third planetary gear mechanisms 7, 8, and 9 that are arranged around the input shaft 3 in order from the side near the torque converter 2, and a first frictional engagement element for transmission. The second clutches 10 and 11, the first to third brakes 12, 13 and 14, and a plate-like coupling 15 are included.

  Each of the planetary gear mechanisms 7 to 9 includes a sun gear 16, a planetary gear 17 that meshes with the sun gear 16, a carrier 18 that supports the planetary gear 17, and a ring gear 19 that meshes with the planetary gear 17. The relationship between these, the clutches 10 and 11, and the brakes 12 to 14 is set as follows.

  (I) The input shaft 3 is connected to the sun gear 16 of the third planetary gear mechanism 9.

  (Ii) The sun gears 16 and 16 of the first and second planetary gear mechanisms 7 and 8 are connected to each other.

  (Iii) The ring gear 19 of the first planetary gear mechanism 7 and the carrier 18 of the second planetary gear mechanism 8 are connected.

  (Iv) The ring gear 19 of the second planetary gear mechanism 8 and the carrier 18 of the third planetary gear mechanism 9 are connected.

  (V) The output gear 5 is connected to the carrier 18 of the first planetary gear mechanism 7.

  (Vi) The sun gears 16 and 16 of the first and second planetary gear mechanisms 7 are connected to the input shaft 3 via the first clutch 10 so as to be intermittent (disconnectable / connectable).

  (Vii) The carrier 18 of the second planetary gear mechanism 8 is connected to the input shaft 3 via the second clutch 11 so as to be intermittent.

  (Viii) The ring gear 19 of the first planetary gear mechanism 7 and the carrier 18 of the second planetary gear mechanism 8 are connected to the transmission case 6 via the first brake 12 and the plate-like coupling 15 in an intermittent manner. .

  (Ix) The ring gear 19 of the second planetary gear mechanism 8 and the carrier 18 of the third planetary gear mechanism 9 are connected to the transmission case 6 via the second brake 13 in an intermittent manner.

  (X) The ring gear 19 of the third planetary gear mechanism 9 is connected to the transmission case 6 via the third brake 14 so as to be intermittent.

  Based on the above configuration, by selecting the combination of operation / non-operation of the frictional engagement elements (the clutches 10 and 11 and the brakes 12 to 14), the shift speeds obtained by the planetary gear mechanisms 7 to 9 are changed between the sixth forward speed and the reverse speed. It can be switched automatically between. The specific relationship between the above combination and the shift speed will be briefly described with reference to FIG.

First forward speed The first clutch 10 and the first brake 12 operate. The rotation of the input shaft 3 is decelerated at a large reduction ratio by the first planetary gear mechanism 7 and is output from the carrier 18 of the first planetary gear mechanism 7 to the output gear 5.

Second forward speed The first clutch 10 and the second brake 13 operate. The rotation of the input shaft 3 is input to the sun gear 16 of the first planetary gear mechanism 7 and simultaneously to the ring gear 19 of the first planetary gear mechanism 7 via the second planetary gear mechanism 8. Therefore, the input rotation is decelerated at a reduction ratio smaller than that in the case of the first speed, and is output from the carrier 18 of the first planetary gear mechanism 7 to the output gear 5.

Third forward speed The first clutch 10 and the third brake 14 operate. The rotation of the input shaft 3 is input to the sun gear 16 of the first planetary gear mechanism 7 and simultaneously input to the ring gear 19 of the first planetary gear mechanism 7 via the third and second planetary gear mechanisms 9 and 8. Is done. For this reason, the input rotation is decelerated at a reduction ratio smaller than the second speed and is output from the carrier 18 of the first planetary gear mechanism 7 to the output gear 5.

Forward fourth speed Both the first and second clutches 10 and 11 are operated. The rotation of the input shaft 3 is input to the sun gear 16 of the first planetary gear mechanism 7 and also input to the ring gear 19 of the first planetary gear mechanism 7 as it is via the second planetary gear mechanism 8. As a result, the entire first planetary gear mechanism 7 rotates integrally with the input shaft 3, and rotation with a reduction ratio of 1 is output from the carrier 18 to the output gear 5.

Forward fifth speed The second clutch 11 and the third brake 14 operate. The rotation of the input shaft 3 is directly input to the ring gear 19 of the first planetary gear mechanism 7 via the second planetary gear mechanism 8 and at the same time via the third and second planetary gear mechanisms 9 and 8. It is also input to the sun gear 16 of the gear mechanism 7. As a result, the input rotation is accelerated and output from the carrier 18 of the first planetary gear mechanism 7 to the output gear 5.

Forward 6-speed The second clutch 11 and the second brake 13 operate. The rotation of the input shaft 3 is directly input to the ring gear 19 of the first planetary gear mechanism 7 via the second planetary gear mechanism 8 and simultaneously the sun gear 16 of the first planetary gear mechanism 7 via the second planetary gear mechanism 8. Is also entered. As a result, the input rotation is increased at a speed increasing ratio larger than the fifth speed, and is output from the carrier 18 of the first planetary gear mechanism 7 to the output gear 5.

Reverse speed Both the first and third brakes 12 and 14 are operated. The rotation of the input shaft 3 is input to the sun gear 16 of the first planetary gear mechanism 7 via the third and second planetary gear mechanisms 9 and 8. At this time, when the rotation direction is reversed in the second planetary gear mechanism 8, rotation in the direction opposite to the rotation direction of the input shaft 3 is output from the carrier 18 of the first planetary gear mechanism 7 to the output gear 5.

  The first and second clutches 10 and 11 and the first to third brakes 12 to 14 constituting the speed change mechanism 4 are hydraulic clutches that are operated by hydraulic pressure from an engine-driven hydraulic pump, as with the lockup clutch 2f. And the engaged / disengaged state is established by controlling the engagement torque capacity.

  Further, by controlling the engagement torque capacity to an intermediate region between complete engagement and release, a so-called half-clutch (slip) state that is an intermediate state is obtained.

  Next, the slip control means 20 that performs slip control for absorbing torque fluctuation due to acceleration / deceleration during non-shifting will be described.

  FIG. 3 shows a block configuration of the slip control means 20.

  The slip control means 20 includes a control unit 21 and a throttle opening degree detection unit 22 that detects the throttle opening degree of the engine as a detection unit that detects and sends an operation situation serving as control data to the control unit 21. The vehicle speed detecting unit 23 for detecting the vehicle speed and the facing temperature detecting unit 24 for detecting the facing temperature of the frictional engagement element are provided.

  The facing temperature detection unit 24 may count the number of slips and time, and may estimate the facing temperature from the count value, or may estimate the facing temperature from the oil temperature.

  The controller 21 mainly performs the following operation.

  i. Based on the throttle opening and the vehicle speed detected by the throttle opening detection unit 22 and the vehicle speed detection unit 23, it is determined whether the running state is a lock-up region, a converter region, or a slip region.

  For example, as shown in FIG. 4, the control area includes a converter area on the relatively low vehicle speed side, a lock area on the relatively high vehicle speed side, and a slip area between the converter and the lock up area.

  ii. When it is determined that the running state is in the slip control region, the target slip amount at that time (predetermined target slip amount according to claim 1) is obtained from a map based on the vehicle speed and the throttle opening.

  iii. A normal input rotational speed is obtained from the output rotational speed of the transmission and the gear ratio, and the target input rotational speed is obtained by adding the target slip amount thereto.

  iv. In order to obtain the target input rotational speed, the slip control is executed for the frictional engagement element that forms the gear stage at that time (the predetermined gear stage in claim 1).

  In the example of FIG. 2, a gear stage is formed by two friction engagement elements at each stage. Hereinafter, for the sake of convenience, two frictional engagement elements that form a gear stage during slip control will be referred to as a first shift clutch and a second shift clutch.

  In this slip control, a first control for slipping the first transmission clutch while completely engaging the second transmission clutch and a second control for slipping the second transmission clutch while completely engaging the first transmission clutch are preset. Use them according to the usage conditions.

  Details of the control will be described in detail with reference to FIGS.

  FIG. 5 shows the flow of slip control.

  First, it is determined in step S1 whether or not the vehicle is in the slip control region. If YES, the lockup clutch 2f shown in FIG. 1 is turned on (lockup state) in step S2.

  In step S3, it is determined by the flag which of the first and second controls was used for the previous slip control, and if F = 0 (which is the first control, neither), the process proceeds to step S4.

  In step S4, the facing temperatures T1 and T2 of the two shifting clutches are compared, and the control for selecting the shifting clutch having the lower facing temperature as a slip target is selected. That is, when T1 <T2, slip control (first control) by the first shift clutch is executed at step S5a, and when T1> T2, slip control (second control) by the second shift clutch is executed at step S5b. Is done.

  If it is determined in step S3 that F = 1 (the previous control is the first control), the process directly goes to step S5a. If F = 2 (the previous control is the second control), the process directly goes to step S5b. Transition.

  When the slip control (first and second control) is performed in steps S5a and S5b, for example, the normal input rotational speed is obtained by multiplying the output rotational speed of the transmission by the reverse gear ratio, and the normal input rotational speed is set to the target. Add the slip amount to find the target input speed.

  Then, in order to obtain this target input rotational speed, one shift clutch (the second shift clutch in the case of the first control, the first shift clutch in the case of the second control) is fully engaged, The engagement torque capacity of the transmission clutch is controlled (for example, feedback control) to be in the slip state.

  This slip control can effectively absorb engine torque fluctuations.

  After execution of this slip control, a flag is set at steps S6a and S6b in FIG. 5 (F = 1 or F = 2), and at step S7a and S7b, the facing temperatures T1 and T2 of the speed change clutch are set to the set values A and B, respectively. It is determined whether or not (A = B or A ≠ B) is exceeded. If NO (facing temperature is less than the set value), the process returns to step S1.

  On the other hand, if YES in steps S7a and S7b (facing temperature exceeds the set value), if the control is continued, the thermal load of the shifting clutch being controlled will be excessive, so that it does not meet the use conditions. In S8b, switching control from the first control to the second control or from the second control to the first control is performed.

  The contents of this switching control will be described with reference to FIG. 6. For example, when switching from the first control to the second control, for the first shifting clutch that is slipping, the fastening torque capacity is gradually increased toward complete engagement by feedforward control. With respect to the second shift clutch in the fully engaged state, the engagement torque capacity is gradually decreased toward the target slip amount by feedback control.

  Thus, the slip target is switched from the first shift clutch to the second clutch or vice versa.

  As described above, when the slip control is executed by selecting the lower facing temperature in steps S4 to S5a and S5b, and the facing temperature exceeds the set values A and B in steps S7a, S7b to S8a and S8b. In order to take two damage countermeasures to switch the slip target, in other words, to use the two shift clutches properly based on the use conditions set for damage reduction, and to perform slip control using only a specific shift clutch and In comparison, damage to the transmission clutch can be suppressed and its durability can be improved.

  Further, in the transition period of switching, while increasing the engagement capacity of the transmission clutch of the switching source (during slip) as described above, while reducing the engagement capacity of the transmission clutch of the switching destination, while ensuring the target slip amount, The control can be switched smoothly.

  After the switching control in steps S8a and S8b in FIG. 5, the process proceeds to steps S5b and S5a to steps S7b and S7a. When the facing temperature exceeds the set values A and B, the switching control is performed again.

  Further, the comparison of the facing temperatures of the first and second shift clutches and the selection of the low temperature side are performed only at the start of the slip control, and the control cycle after the second time (NO in steps S7a and S7b becomes step). (When returning to S1), in step S3, the shift clutch used immediately before is selected as still satisfying the use conditions, and the first control in step S5a or the second control in step S5b is executed. .

Second embodiment (see FIG. 7)
Only differences from the first embodiment will be described.

  In the first embodiment, only the first and second shift clutches are selectively used based on the usage conditions (lower facing temperature, whether the facing temperature is lower than a set value). there is a case in which situation in which the facing temperature of the transmission clutch do not want both to use both for equal to or greater than the set value occurs.

  In the second embodiment, in this case, as an alternative, the control is switched to the slip control of the lockup clutch (third control not using the shift clutch).

  That is, in the flowchart of FIG. 7, steps S11 to S17a and S17b are the same as steps S1 to S7a and S7b of the flowchart of FIG.

  If YES in steps S17a and S17b (the facing temperature of the shifting clutch during slipping exceeds the set values A and B), in the second embodiment, the other (being engaged) in steps S18a and S18b. It is determined whether or not the facing temperature of the speed change clutch is lower than the set values B and A, and only when NO (less than the set values B and A), the first control is performed in steps S19a and S19b as in the first embodiment. Is switched to the second control or vice versa, and the control is executed in steps S15b and S15a.

  On the other hand, if YES is determined in steps S18a and S18b (set values B and A are exceeded), switching control from the first control or the second control to the third control by the lockup clutch is performed in step S20. In step S21, the third control is executed.

  As in the switching from the first control to the second control or vice versa, the switching from the first or second control to the third control in steps S20 and S21 is performed by feedforward control for the shift clutch in the slip state. While the fastening torque capacity is gradually increased toward complete fastening, the fastening torque capacity is gradually reduced toward the target slip amount by feedback control for the lock-up clutch that is in the fastening state.

  As a result, the slip target is switched from the first or second shift clutch to the lock-up clutch, and then the process returns to step S1.

  As described above, when neither the first or second shift clutch is adapted to the use condition, the intended purpose of improving the durability of the shift clutch is effectively achieved by switching to the slip control of the lockup clutch. Can be achieved.

Other Embodiments (1) In both the above embodiments, the facing temperatures of both shift clutches are compared in step S4 of FIG. 5 and step S14 of FIG. 7, and the control is selected and executed with the lower one meeting the use conditions. However, the control may be selected and executed based on the usage frequency and the degree of wear of the two speed clutches.

  This is the same when determining the conditions for switching control in steps S7a and S7b in FIG. 5 and steps S17a and S17b in FIG. 7, and the control is performed when the usage frequency and the degree of wear exceed the set values. You may make it switch.

  The frequency of use can be obtained by counting the number of times used for slip control and the slip time. The degree of wear can be estimated, for example, by adding a change in fastening capacity to the number of uses and slip time.

  (2) In both the above embodiments, when the gear stage is formed by two frictional engagement elements, one is used as the first frictional engagement element and the other as the second frictional engagement element. When the gear stage is formed by two frictional engagement elements, a configuration in which these three frictional engagement elements are used properly may be employed.

  Here, the “first frictional engagement element” and the “second frictional engagement element” in the present invention are divided into two types of “friction engagement elements to be slipped” and “friction engagement elements to be completely engaged” at the time of slip control. It is a term.

  Therefore, for example, when three frictional engagement elements of X, Y, and Z are properly used, the “first control” referred to in the present invention means that, for example, X is slipped as the first frictional engagement element, while Y and Z are the second frictional engagement elements. “Second control” means that Y (or Z) is slipped as a second friction engagement element, while X and Z (or Y) are completely engaged as a first friction engagement element. This is the control to be performed.

  Alternatively, two of X and Y (or Z) are slipped in the first control, while only Z (or Y) is completely fastened, and only Z (or Y) is slipped in the second control, while X and Y (Or Z) may be completely fastened.

1 is a skeleton diagram showing an overall configuration of an automatic transmission according to a first embodiment of the present invention. It is a figure which shows the relationship between the combination of the friction engagement element in the same transmission, and a gear stage. It is a block block diagram which shows the structure of the control means concerning the embodiment. It is a figure which shows the content of the area | region setting by a control means. It is a flowchart which shows the flow of the slip control by a control means. It is a figure for demonstrating the content of the switching control by a control means. It is a flowchart which shows 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Torque converter 2f Lock-up clutch 3 Input shaft 4 Transmission mechanism 10,11 Clutch 12-14 as a frictional engagement element Same brake 20 Slip control means 21 Control part 22 Throttle opening degree detection part 23 Vehicle speed detection part 25 Facing temperature detection part

Claims (6)

A control apparatus for an automatic transmission having first and second frictional engagement elements that are engaged to form a predetermined shift speed, and slip control means that controls the frictional engagement elements to a predetermined target slip amount during non-shifting. The slip control means slips the first friction engagement element while completely engaging the second friction engagement element and completely slips the first friction engagement element while slipping the second friction engagement element. A control device for an automatic transmission, wherein the second control to be engaged is configured to be selectively used while maintaining a predetermined gear position based on a predetermined use condition.
  The slip control means is configured to select and execute the one having the lower facing temperature of the frictional engagement element to be slipped out of the first and second controls as being suitable for the use condition at the start of the slip control. 2. The control device for an automatic transmission according to claim 1, wherein the control device is an automatic transmission.   The slip control means switches to the other control on the assumption that it does not conform to the use conditions when the facing temperature of the frictional engagement element during the slip becomes equal to or higher than the set value during execution of the first control or the second control. 3. The automatic transmission control device according to claim 1, wherein the control device is configured as described above.   In the transition period of control switching, the slip control means increases the fastening capacity of the switching source frictional engagement element, and responds to the increase in the fastening capacity of the switching source frictional engagement element. 4. The control device for an automatic transmission according to claim 3, wherein the fastening capacity is reduced.   A fluid transmission device with a lock-up clutch, wherein the slip control means releases the lock-up clutch from the first or second control when neither of the first and second frictional engagement elements meet the usage conditions. The control device for an automatic transmission according to any one of claims 1 to 4, wherein the control device is configured to switch to a third control for slipping.   The slip control means increases the fastening capacity of the switching friction engagement element during the transition period from the first control or the second control to the third control, while increasing the fastening capacity of the switching friction fastening element. 6. The automatic transmission control device according to claim 5, wherein the engagement capacity of the lock-up clutch is reduced in response to the above.

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