JPS61171957A - Lock-up control device of automatic speed change gear - Google Patents

Abstract

PURPOSE:To prevent drop of car speed smoothly by transmitting ON signal of lock-up to a lock-up control means when actual car speed is decreased more than a set car speed over a predetermined width from a setting car speed during operation of a fixed speed traveling device. CONSTITUTION:Signals from a car speed sensor L and a car speed setting switch J are input in a fixed speed traveling device K controlling output of an engine, and when actual car speed is decreased from the set speed, over a predetermined width determined according to the set car speed, a lock-up releasing means M is operated to transmit ON signal of lock-up to a lock-up control means N. By this, when the car speed is decreased even if a throttle valve is opened fully, lock-up is controlled to obtain increase action by torque converter, then the decrease in car speed can smoothly be prevented relatively.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a control device for controlling the operation of a lock-up mechanism that directly connects the input and output shafts of a torque converter in an automatic transmission installed in a vehicle. More specifically, the present invention relates to a control device for a lock-up mechanism in an automobile equipped with a constant speed traveling device.

(Prior Art) Generally, a torque converter used in this type of automatic transmission has a pump impeller driven by an engine, a turbine connected to a speed change gear mechanism, and a stator fixed between both rows. As the pump rotates, the hydraulic oil that fills between these flows into the turbine along the pump blades, giving torque to the turbine, and then returns to the pump through the stator. By repeatedly circulating hydraulic oil, the reaction force of the turbine is increased and the comb torque is increased.
When the rotational speed of the turbine is higher than the rotational speed of the pump, the increase in torque is large, and as the rotational speed of the turbine approaches the rotational speed of the pump, the increase in torque becomes smaller. However, on the other hand, there is a drawback that a certain degree of reduction in power transmission efficiency due to slip between the pump and the turbine cannot be avoided, resulting in poor fuel efficiency.

Therefore, in order to eliminate such slips, eliminate the decrease in power transmission efficiency, and reduce fuel consumption, recently,
The input and output shaft of the torque converter is connected and disconnected by a lockup clutch (direct clutch) that is operated by controlling the supply and discharge of hydraulic oil using electromagnetic means (solenoid valve), and the power transmission path from the engine to the transmission gear mechanism is switched. A lock-up mechanism (direct connection mechanism) is provided, and under operating conditions where the rotational speed of the turbine is close to the rotational speed of the pump, the lockup mechanism directly connects the pump and the turbine and locks up! .

It has been proposed to carry out control. In this way, in areas where the pump and turbine rotations are different, the torque converter provides a smooth gear shifting action, and in areas where the pump and turbine rotations are close to each other, the lock-up clutch is activated to control the engine output shaft. By directly connecting the input shaft of the transmission gear mechanism to the input shaft of the transmission gear mechanism, fuel efficiency can be improved.

On the other hand, in recent years, constant speed driving devices have been put into practical use that automatically maintain the medium speed of a vehicle at a desired vehicle speed set by the driver. This constant speed traveling device sets the vehicle speed as a target value for constant speed traveling by a set operation by the driver when the vehicle speed reaches a desired vehicle speed, and thereafter compares this set vehicle speed with the actual intermediate speed. Then, when a difference occurs between the sounds of rain, the throttle valve of the engine is controlled according to the difference, thereby making the actual vehicle speed match the set vehicle speed.

However, when the vehicle enters a σ slope while this constant speed running device is in operation, the device operates to increase the engine throttle gf by 1 degree in an attempt to maintain the vehicle speed, but due to the slope of the road, the device increases the engine throttle gf by 1 degree. Even if the throttle opening is fully opened, the vehicle speed may gradually decrease and deviate from the set vehicle speed.

In order to solve the above-mentioned h problem that is common to automobiles equipped with constant speed traveling devices, the following invention has been proposed, for example, in Japanese Patent Application Laid-Open No. 57-121713.

In an automobile equipped with an automatic transmission, when the difference between the actual vehicle speed and the set intermediate speed becomes equal to or greater than a predetermined value when a constant speed traveling device is activated, the present invention shifts the gears of the automatic transmission for a certain period of time.
It is designed to automatically downshift. According to this, even when the vehicle speed gradually decreases when the throttle opening is increased only by increasing the throttle opening, the required driving force is obtained by downshifting the transmission, and the actual vehicle speed is restored to match the set vehicle speed. will be done.

However, in the case of the above proposal, there is a problem that a shift shock is likely to occur when downshifting or when shifting back to the original gear after downshifting and the actual vehicle speed matches the set heavy speed.

(Purpose of the Invention) For this reason, in the present invention, when the vehicle speed decreases even when the throttle is fully opened, such as when the vehicle enters a hill while the constant speed traveling system is activated, the lock-up is i-controlled and the torque is increased. The purpose of this is to obtain a torque increasing effect by the converter to relatively smoothly prevent a decrease in vehicle speed.

(Structure of the Invention) As shown in FIG. In an automatic transmission equipped with a lock-up means that switches the power transmission path by connecting and disconnecting with fluid, there is a speed sensor F that detects the speed of the power transmission system of a vehicle equipped with the automatic transmission, and a large load on the engine A. An engine load sensor G is provided to detect the engine load, and the output signals from the two sensors F and G are compared with a lockup control line h, which is set and stored in advance, in a lockup determination means (2) to determine whether or not lockup is to be performed. The basic configuration is that the lock-up control means operates and releases the lock-up means based on the lock-up A on/off signal from the lock-up determining means I, and the vehicle speed sensor L and , while the constant speed traveling device fK is in operation, which receives the set vehicle speed signal from the vehicle speed setting switch J and the vehicle speed signal from the vehicle speed sensor L, issues a signal to the engine to control the engine output, and maintains the vehicle speed at approximately the set vehicle speed. A lock-up release means that compares the actual vehicle speed detected by the sensor L with a set vehicle speed and issues a lock-up off signal to the lock-up control means N when the actual vehicle speed decreases from the set vehicle speed by more than a predetermined width determined according to the set vehicle speed. It is characterized by comprising M.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. First, FIG. 2 shows the mechanical structure and fluid control circuit of an automatic transmission to which this embodiment is applied. Yu.

,o9,. 1. Yo1.7. The driver converter 10 and the multi-speed gear teeth 11! It consists of a mechanism 20 and an overdrive speed change m* mechanism 40 disposed between the two.

The torque converter 10 includes a pump 13 directly connected to the output shaft 3 of the engine 2 via a drive plate 11 and a case 12, a turbine 14 disposed in the case 12 facing the pump 13, and a combination of the pump and the turbine. 14, and an output shaft 16 is coupled to the turbine 14. Also,
A lock-up clutch 17 is installed between the output shaft 16 and the case 12. This lock-up clutch 17 is constantly pressed in the engagement direction by the pressure of the working fluid circulating within the torque converter 10, and is released when release fluid pressure is supplied from the outside.

The multi-speed gear mechanism 20 has a front planetary gear mechanism 21 and a rear planetary gear mechanism 22, and sun gears 23, 24 of both mechanisms 21, 22 are connected by a connecting shaft 25. Input shaft 26 to this multi-speed 6Ii vehicle mechanism 20
is connected to the connecting shaft 25 via the front clutch 27,
In addition, the front planetary gear mechanism 2
are configured to be connected to the ring gears 29 of 1, respectively,
and the connecting shaft 25, that is, the double star gear mechanism 21°2
A second brake 31 is provided between the sun gear 23, 24 and the transmission case 30 at 2. The binion carrier 32 of the front planetary gear mechanism 21 and the ring gear 33 of the rear planetary gear mechanism 22 are connected to the output shaft 34, and the binion carrier 35 of the rear planetary gear mechanism 22 and the transmission case 30 are connected to each other. A low reverse brake 36 and a one-way clutch 37 are interposed between them.

On the other hand, in the overdrive transmission gear mechanism 40,
A binion carrier 41 is connected to the output shaft 16 of the torque converter 10, and a sun gear 42 and a ring gear 43 are connected by a direct coupling clutch 44. Further, an overdrive brake 45 is provided between the sun gear 42 and the transmission case 30, and the ring gear 43 is connected to the input shaft 2 to the multi-speed gear mechanism 20.
6.

- The multi-speed gear mechanism 20 having the configuration as shown in F is conventionally known, and has three forward speeds and one reverse speed between the input shaft 26 and the output shaft 34 by selectively operating the clutches 27, 28 and the brakes 31,36. The transmission ratio is shown in blue. Further, the overdrive speed change gear mechanism 40 directly connects the output shaft 16 of the 1 to LU converter 10 and the input shaft 26 to the multi-stage speed change gear mechanism 20 when the clutch 44 is engaged and the brake 45 is released. When the clutch 44 is released and the brake 45 is engaged, the shaft 16.26 is engaged in overdrive.

Next, the fluid control circuit 5o of the automatic transmission will be explained.

The working fluid discharged into the main line 52 from the oil pump 51 which is constantly driven by the engine output shaft 3 via the torque converter 10 is guided to the select valve 54 after its oil pressure is adjusted by the pressure regulating valve 53 . This select valve 54 is P.

It has a range of R, N, D, 2.1, and D, 2. The main line 52 is connected to the boat a at the lunge.

This boat a is connected to the rear clutch 2 via a line 55.
Therefore, in each of the forward ranges described above and 2.1, the rear clutch 28a is connected to the rear clutch 28a.
is always kept in a fastened state.

Moreover, the boat is the first boat. Second. Third. 4th control line 5
6.57.58.59.

These control lines 56 to 59 are led to one end of a 1-2 shift valve 61, a 2-3 shift valve 62, a 3-4 shift valve 63, and a lock-up valve 64, respectively.
Each control line 56-59 has a drain line 66.
67, 68, and 69 are branched, and the first drain line opens and opens these drain lines 66 to 69, respectively. Second. Third. Fourth solenoids 71.72, 73.74 are provided. When these solenoids 71 to 74 are OFF, the pressure inside the drain lines 66 to 69□ML, T*Ji6t61'llll fins 56 to 59 is zero, but when they are ON, they close the drain lines 66 to 69. By increasing the pressure in the control lines 56-59, the 1-2 shift valve 61.
Spools 61a, 62a, 63a in 2-3 shift valve 62.3-4 shift valve 63 and lock-up valve 64
, 64a from the illustrated positions (a), (b), and (c), respectively.
, (d) direction.

The boat a in the select valve 54 also reaches the shift valve 61 via a line 76 branched from the above line, and the spool 61a is moved in the direction (A) by the working fluid from the first control line 56. sometimes line 7
7 of the second brake 31 through a second lock valve 78 and a line 79.
It communicates with the fastening-side port 31a' in the cutuator 31a. As a result, working fluid is supplied to the boat 318', and the second brake 31 is engaged.

Here, in the D range, the second lock valve 78 is supplied with working fluid from both boats b and C of the select valve 54 via the line 80.81, and the second lock valve 78 is supplied with the working fluid through the line 77.79 as shown in the figure. In the 2nd range where boat C is closed, although it is maintained in a communicating state,
Spool 78a is supplied with working fluid only from boat b.
moves downward, thereby connecting line 80.79. Therefore, in the 2nd range, the second brake 3
1 is tightened regardless of the state of the 1-2 shift valve 61.

Also, boat C connected to main line 52 in D range.
is led to the 2-3 shift valve 62 by the line 81 via the one-way comparison valve 82. And said 2-
When the spool 62a of the 3-shift valve 62 is moved in the (b) direction by the working fluid from the second control line 57, it is connected to the line 83, which is further branched into lines 84 and 85, one of which is connected to the second brake 31. The other end is connected to the release side port 31a11 of the seventh mouth evaporator 31a, and the other end is connected to the 7th mouth evaluator 27a of the front clutch 27. As a result, working fluid is supplied to the boat 31a'' and the actuator 27a, the second brake 31 is released, and the front clutch 27 is engaged.

In addition, in the lunge, the boat d of the select valve 54 communicates with the main line 52, and the working fluid is guided to the 1-2 shift valve 61 via the line 86, and the valve 6
When the spool 61a of No. 1 is in the illustrated position, it is further connected to the actuator 36a of the low reverse brake 36 via a line 87. As a result, the low reverse brake 36 is engaged.

Further, in the R range, boat e as well as boat d are connected to the main line 52, so that the working fluid is guided to the 2-3 shift valve 62 through the line 88, and the spool 62a of the valve 62 is at the position shown in the figure. At some point, the line 83 and line 84.85 connect to the release side boat 31a'' of the second brake actuator 31a and the actuator 27a of the front clutch 27.As a result, in the R range, the front clutch is connected to the low reverse flake 36 as well as the front clutch. 2
7 is concluded. In this case, since the boat a is closed, the rear clutch 28 is released.

The main line 52 is selectively switched to its course by the select valve 54 as described above, and at the same time, the branch line 89
．． 90 to the 3-4 shift valve 63 and the engagement side boat 45a' of the actuator 45a of the overdrive brake 45. The line 89 led to the 3-4 shift valve 63 is further connected to the line 91.92 when the spool 63a of the valve 63 is in the position shown.
One line 91 leads to the actuator 448 of the direct coupling clutch 44, and the other line 92 leads to the release side boat 45a'' of the overdrive brake actuator 45a.

Therefore, when the 3-4 shift valve 63 is in the illustrated state, the overdrive brake actuator 45a
Both boats 45a-, 45a”I on the engagement side and the release side
c. □smagh□O boat bar drive brake 4
5 is released, and the direct coupling clutch 44 is in a engaged state. And the spool 63a of the 3-4 shift valve 63
is moved in the (c) direction by the working fluid from the third control line 58, lines 91 and 92 are drained, thereby releasing the direct coupling clutch 44 and engaging the overdrive brake 45.

Further, working fluid is led from the main line 52 to a lock-up valve 64 via a branch line 93 that passes through the pressure regulating valve 53. When the spool 64a of the valve 64 is in the position shown, it reaches the inside of the torque converter 10 via the line 94, and disengages the lock-up clutch 17 inside the torque converter 10.

Then, when the spool 64a of the lock-up valve 64 is moved in the (d) direction by the working fluid from the fourth control line 59, the line 94 is drained, so that the lock-up clutch 17 is connected to the torque converter 1.
It is tightened by a fluid pressure within 0.

In addition to the above configuration, this fluid control circuit includes a cutback valve 95 that stabilizes the oil pressure from the pressure regulating valve 53. A vacuum throttle valve 96 that changes the line pressure by the pressure regulating valve 53 according to the magnitude of the intake negative pressure. and a throttle backup well 9 that assists the throttle valve 96.
7 is set number.

Regarding the above configuration, the relationship between each shift solenoid 71 to 73 and the gear position in the D range, the relationship between the solenoid 74 and lockup, and the relationship between the operating state of the clutch and brake in each range and the gear position are shown in the first diagram. ．． Second. It is shown in Table 3.

Next, the electric control circuit of the automatic transmission 1 will be explained using FIG. 3.

As shown in FIG. 3, this electric control circuit 100 is provided with a speed change control circuit 101 and a lock-up control circuit 102, and the rotation speed of the turbine 14 in the torque converter 10 is detected at these zero paths 101 and 102. a turbine rotation signal a from the turbine zero rotation sensor 103,
A throttle opening signal from a throttle opening sensor 104 that detects the opening of the throttle valve 4 in the engine 2 is input. Then, in response to these signals a and b, the speed change control circuit 101 and the lock-up control circuit 102 perform the speed change and lock-up that are preset according to the turbine rotational speed and the throttle opening as shown in No. 4@l. According to the map, the driving state is in the shift up zone.

Determine whether the shift is in the downshift zone or hold zone, and determine whether the zone is in the lockup activation or release zone, and depending on the determination results, shift control signal @C and lockup control signal d
is output to the first to third solenoids 71 to 73 and the fourth solenoid 74, respectively. As a result, the first to third solenoids 71 to 73 are operated to the ON or OFF state corresponding to the speed stage to be set according to Table 1 above, and the automatic transmission 1 is operated at the required speed according to the operating range. The fourth solenoid 74 is turned on and off according to Table 2, and the lock-up clutch 17 is activated or released depending on the operating range.

On the other hand, the book-1111@ is equipped with a constant speed traveling device 1105 that maintains the traveling speed during the automatic mode at a desired set speed. This constant speed traveling device 105 receives a vehicle speed signal e from a heavy speed sensor 106 that detects the actual traveling speed V,
Upon receiving the vehicle speed setting signal @f from the vehicle speed setting switch 107 operated by the driver, the vehicle speed at the time of input of the signal f is set as the target speed for constant speed driving, and this set vehicle speed V and Y are set as the vehicle speed signal described above. When the actual vehicle speed V indicated by e is compared with the actual vehicle speed V, and if a difference arises between the two, the control valve 7 of the throttle valve 4 is operated so as to eliminate the difference, that is, to make the actual vehicle speed ■ match the set vehicle speed Vo. 10
A throttle control signal Q is output to the terminal 8.

However, when the difference between the actual vehicle speed V and the set vehicle speed Vo exceeds a predetermined value ΔV (for example, 101 to 11) when the constant speed traveling device fil 05 is activated, the control circuit 100 of the automatic transmission 1 has the following information: A lock-up release circuit 109 receives a speed reduction signal indicating this, and a vehicle speed change detection circuit 110 receives the vehicle speed signal e from the vehicle speed sensor 106 and calculates the rate of decrease in vehicle speed, that is, the speed decrease rate*.
and is provided. Note that this predetermined value ΔV may be a constant value, or may be a value corresponding to the set vehicle speed VO, such as a value proportional to the set vehicle speed Vo.

Then, the lockup release circuit 109 activates the lockup III control circuit 10 when the speed difference exceeds the predetermined value ΔV.
2, the lockup control circuit 102 outputs a control signal d to the fourth solenoid 74 to release the lockup regardless of the determination result based on the map shown in FIG. , the lock-up clutch 17 is released. In that case, the lock-up release circuit 109 calculates the lock-up time t(-α·9
．． α: constant) is set, and the off signal i is output only during this time t.

Therefore, as shown in FIG. 5, when the constant speed traveling device 105 is in operation, the actual vehicle speed V decreases due to entering the uphill road, etc., and a speed difference exceeding the predetermined value ΔV from the set vehicle speed Vo occurs. In this case, &ll from the constant speed traveling device 105
The lock-up clutch 17 is turned from on to off by inputting a speed reduction signal to the lock-up release circuit 109 of the I11 circuit 100, but in this case, as shown by arrow X, the uphill resistance is large, etc. Therefore, when the vehicle speed decreases at a large speed decrease rate of 9x, the lock-up clutch 17 is turned off for a proportionally long time tx (-α・VX), and as shown by arrow Y, the climbing resistance is reduced. Since it is relatively small, if the speed reduction rate 9y is small, the lock-up clutch 17 will operate for a relatively short time ty.
It is turned off only during (=α·vy). As a result, when driving on a steep road where it takes a long time to return the actual vehicle speed V to the set vehicle speed v0 by turning off the lock-up clutch 17 and obtaining a 1-rook increase effect of the torque converter, the off time tx becomes longer, and when the lock-up clutch 17 is turned on, the actual vehicle speed V has been returned to approximately match the set vehicle speed "avo". In the case of a gentle uphill road where the set vehicle speed returns to the set vehicle speed V0 in time, the off time ty is correspondingly shortened to prevent the off state from continuing unnecessarily after the set vehicle speed returns to the set vehicle speed VO. In this way,
When the vehicle speed decreases, such as when climbing a hill, the torque converter's torque increasing effect allows the vehicle speed to smoothly return to the set speed, and the time required to return to the set vehicle speed depending on the load such as climbing resistance. Even if the value changes, the lockup will always be released for the required amount of time.

Note that the control circuit 100 that performs the above I control is as follows:
For example, it can be configured by a microcomputer, in which case the control circuit 100 operates according to the flowcharts shown in FIG. 6 and subsequent figures. Next, this operation will be explained.

Main Control First, the flowchart of the main control shown in FIG. 6 will be explained. First, the control circuit initializes various states in step A1, and then determines whether the constant speed traveling device is operating in step A2. judge. Then, during normal driving when the constant speed traveling device is not operating, the range set by the shift lever is read in step A3, and if it is set to lunge, steps A4 to A5 to A9 are executed to lock up. 1"t')>V
@E″E t −t<−7> t 6” “81”
After confirming the above, shift to 2nd gear if an overrun occurs, and shift to 1st gear if an overrun does not occur. Also, if it is set to 2 ranges, step △4 above.
From step A10, step Al1. A12
Execute to release lock-up and shift to 2nd gear.

Furthermore, when the range is set to a range other than the range 2 or range 2, that is, the D range, steps A10 to A13 to A15 are executed to perform shift-up control, shift-down control, and lock-up control, which will be described later.

On the other hand, during constant speed running*+ry, lock-up control during constant speed running is performed according to steps A2 to AI6 to A20 described above. That is, step A
16. At step A17, the vehicle speed V is read from the signal from the vehicle speed sensor, and the rate of drop in the vehicle speed, that is, the speed reduction rate Q is determined, and at step A18, the set vehicle speed vG@ is read from the signal from the constant speed traveling device. Then, in step A19, this set vehicle speed Vo and the above vehicle speed ■
When the actual vehicle speed decreases beyond a predetermined value, a lock-up off time 1 (=α・Q) proportional to the speed decrease rate O is set in step A20, and this is set as Ill.
Set the lockup release timer provided in the 111 circuit.

Shift-up control On the other hand, in the shift-up control of step A13 in the above main $1111, as shown in FIG. When it is, it is impossible to shift up, so the control is terminated. When the gear stage is in a state other than 4th speed, the current throttle opening is read according to steps 82 to B5, and the set turbine rotation speed Tmap corresponding to the read throttle opening is read from the preset and stored shift-up map. , Also, real turbine rotation 1! Read T and set the above-mentioned set turbine rotation speed T.
Compare with map. Here, the shift-up map stores the set turbine rotation speed Tmap corresponding to each throttle opening degree as a shift-up line Mu, as shown in FIG. 8, and this shift-up line Mu is shown in FIG. This corresponds to the boundary line X between the shift up zone and the hold zone. When the actual turbine rotation speed Tmap is larger than the set turbine rotation speed Tmap, that is, when the operating region is in the shift up zone shown in FIG. 4 or FIG. 8, if the shift up flag F1 is "0", , from step B5 to step 86 to B8, the flag F
1 to "1" and then shift up the gear by one gear. The shift-up flag F1 indicates that the shift-up control was performed at °°1''. Therefore, if the flag F1 is already set to 1'' in step B6, it is necessary to shift up again. Control ends without any change. Further, when it is determined in step 85 that the actual turbine rotational speed Tmap is smaller than the set turbine rotational speed Tgtap, the set turbine rotational speed Tmap is multiplied by 0°8 to obtain the eighth
A new shift up line Mu= shown by a broken line in the figure is set. Then, only when the actual turbine rotation speed T is smaller than the new set turbine rotation speed 7map corresponding to this aMu=, the shift-up flag F1 is reset to "O" in preparation for the next shift-up control, and the actual When the turbine rotational speed Tmap is greater than the new set turbine rotational speed Tmap, the control is immediately terminated and shift-down control is performed. The purpose of the control in steps 89 to 811 is to form a hysteresis zone and prevent so-called chattering, which occurs when gear changes are performed in a complicated manner when the turbine rotational speed T is on the shift-up line Mu.

Shift Down Control Also, the shift down control in step A14 in FIG.
The process is executed as follows according to the flowchart of FIG.

First, in step C1, it is confirmed that the automatic transmission is in a gear other than 1st speed, that is, in a gear position where downshifting is possible, and then downshifting control is performed in steps 02 and 4. That is, according to steps C2 to C5, the actual throttle opening degree is read 6oa&:, □1oo□. 627□
The set turbine rotation speed 7sap corresponding to the throttle opening at that time is read out from the shift down line Md set in the Keua t map, and this is compared with the actual turbine rotation speed T. Here, the shift down line Md
corresponds to the boundary l1IY between the hold zone and the downshift zone shown in FIG. Then, when the actual turbine rotation speed T is smaller than the set turbine rotation speed Tsap, that is, when the operating region is in the downshift zone shown in FIG. 4 or FIG. After confirming that the flag F2 has been reset to "1" and setting the flag F2 to "1", the gear stage is shifted down by one gear. In this case as well, if the 7lag F2 has already been set to "1" in step C6, the control ends. Further, in step C5, the actual turbine rotation speed T is set to the set turbine rotation speed 7 a
+ap, the set turbine rotation speed Tmap is divided by 0.8 according to steps C9 to C11 and the first
A new downshift line Md' as shown by a broken line in FIG. Then, only when T > T map, the downshift flag F2 is reset to "0" to prepare for the next downshift.

Lock-up system Furthermore, the lock-up control at step A15 in the main control of FIG. 6 is executed according to the flowchart shown in FIG.

First, in step D1, it is determined whether a lockup release timer is set. In other words, it is determined whether the lock-up release timer is set in step A20 of the chart in FIG. 6 because the speed has decreased beyond a predetermined value, such as when approaching a boarding road while the constant speed traveling device is operating. If it is set, the process proceeds to step D6, where an off signal is output to release the lockup, and the flow ends. If the lock-up release timer is not set, steps D2 to D
5, read the throttle opening and
The set turbine rotation speed T sap corresponding to the throttle opening at that time is read from the lockup release line Moff set in the lockup map as shown in FIG. 2, and this is compared with the actual turbine rotation speed T. When the actual turbine rotational speed 1- is smaller than the set turbine rotational speed Tsap, that is, when it is in the lockup release zone shown in FIG. 12, the lockup is released in step D6.

The actual turbine rotation speed T is equal to the above lock-up release line M.
When it is larger than the set turbine rotation speed Tap corresponding to off, step D7. At D8, as shown by the broken line in FIG. 12, the set turbine rotation speed Tmap corresponding to the lockup operation t/QMOn is read by providing a hysteresis zone of a predetermined width on the turbine rotation speed side of the lockup release line Moff. , this set turbine rotation speed map is compared with the actual turbine rotation speed. Then, when T>Tmap, the lock-up operation is controlled in step D9.

In this way, if it is determined that the lock-up release timer is set in step D1 of -h, the process immediately proceeds to step D6, regardless of which state it is in on the map shown in FIG. Proceed and release the lockup. As a result, when the lock-up release timer is set due to a difference of a predetermined value Δ■ between the actual vehicle speed V and the set vehicle speed Vo due to entering the boarding road etc. when the constant speed traveling device is activated, the lock-up is disabled. It is turned off, and the vehicle speed can be clearly returned to the set value by receiving the torque increasing action of the torque converter.

In addition, this lock-up release time t is set in step A20 of FIG. 6 in proportion to the speed reduction rate 9, so it is long when the load is heavy such as when running up a steep hill, and when the load is high when running on a relatively gentle uphill slope. It becomes shorter when the load is small, such as when driving. As a result, the lock-up release time t is always set to approximately correspond to the time required to return the actual vehicle speed ■ to the set vehicle speed Vo, and the actual vehicle speed returns to the set vehicle speed by 1, *tttm.
Point t' o y 'y 7 y.

Since the knob clutch is returned to the operating state, the lock-up will not remain in the off state even after returning to the set vehicle speed, and it is possible to prevent fuel consumption from deteriorating.

(Effects of the Invention) As described above, according to the present invention, when the constant speed traveling device is activated and the lock-up is activated (on) and the vehicle is traveling, the actual vehicle speed changes from the set vehicle speed due to entering the boarding road, etc. When the actual vehicle speed decreases beyond a predetermined range, the lock-up clutch is released and power is transmitted via the torque converter, so the torque converter can increase the torque and restore the actual vehicle speed to the set vehicle speed. I can do it. Further, due to the power transmission action of the torque converter via the fluid, shocks are less likely to occur when the lock-up clutch is turned on and off, and a smooth return to heavy speed can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of a lock-up device for an automatic transmission according to an embodiment of the present invention, and FIG. An explanatory diagram showing the control circuit, No. 3 Li21 is an electric control l1 route diagram of the automatic transmission, FIG. 4 is a characteristic diagram showing the υ control characteristics by the electric control circuit, and FIG. 5 is used in the present invention. Graph showing the relationship between the operation of a constant speed traveling device and the operation of lockup, No. 6.7.9.1
Figure 1 shows the entire shift control. Flowcharts showing the operations of upshift, downshift and lockup, Figures 8, 10 and 12 are explanatory diagrams showing maps used to control upshift, downshift and lockup, respectively. 1... Automatic transmission 2... Engine 10...
Torque converter 17...Lockup clutch 20.40...Transmission gear mechanism 101...Speed @ control circuit 102...Lockup control circuit 105...Constant speed traveling device 109...Lockup release circuit 110 ...Width speed change detection circuit Fig. 4 y-t''''/al ear m (RPM) Fig. 5 Fig. 8 Fig. 9 Fig. 11 Fig. 12

Claims (1)

[Scope of Claims] A power transmission path connecting and disconnecting a torque converter connected to an output shaft of an engine, a speed change gear mechanism connected to an output shaft of the torque converter, and an input shaft and an output shaft of the torque converter. lockup means for switching the lockup means, electromagnetic means for controlling the supply of pressure fluid to the lockup means for operating the lockup means, a speed sensor for detecting the speed of the power transmission system, and a speed sensor for detecting the speed of the engine load. The output signals of the engine load sensor that detects the size, the speed sensor, and the engine load sensor are input, and these two output signals are compared with a preset and stored lockup control line to turn the lockup on or off. A lock-up determining means for generating a signal, and receiving a lock-up on/off signal from the lock-up determining means, driving and controlling the electromagnetic means based on the on/off signal to operate the lock-up means and its operation. A lock-up control device for an automatic transmission comprising a lock-up control means for controlling release, which includes a vehicle speed sensor and a constant device that receives a set vehicle speed input from the outside, controls engine output, and maintains the vehicle speed at the set vehicle speed above the road. When the actual vehicle speed detected by the vehicle speed sensor decreases from the set vehicle speed by a predetermined width determined according to the set vehicle speed while the speed traveling device is in operation, a lock-up off signal is sent to the lock-up control means. 1. A lockup control device for an automatic transmission, comprising a lockup release means for emitting a lockup.