JPS61248959A - Device for locking up automatic transmission - Google Patents

Abstract

PURPOSE:To reduce the slip of a converter, restrain the rise of temperature and prevent working oil land seal from degradation by expanding the lock-up operating region of a torque converter when the temperature of working oil for an automatic transmission rises. CONSTITUTION:An automatic transmission I is provided with a torque converter D or an oil temperature sensor J for detecting the temperature of working oil in the automatic transmission I and a lock-up region changing means K for receiving the signal from the sensor J to expand the lock-up operating region set by a lock-up region setting means H when the temperature of work ing oil rises. In the normal oil temperature the conveter is operated in a predeter mined lock-up operating resion to set the converter D to the direct connective condition. In the rise of temperature of working oil, the lock-up region changing means K expands and lock-up operating region through the lock-up region setting means H. Thus, the lock-up means E will be operated in the wider region so that the rise of oil temperature will be restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic transmission used in an automobile, and more particularly to a lockup control device for an automatic transmission equipped with a torque converter capable of preventing lockup.

(Prior art) An automatic transmission that combines a torque converter and a speed change gear mechanism, and obtains a plurality of gears by switching the transmission path of the speed change gear mechanism by selectively operating a plurality of hydraulic actuators, is as described above. Due to the slippage of the torque converter, the power transmission efficiency is inferior to that of a vehicle equipped with a manual transmission using a mechanical clutch, and as a result, a vehicle equipped with an automatic transmission is disadvantageous in terms of fuel efficiency. Therefore,
The input and output sides of the torque converter, except when shifting shock is avoided by sliding the input and output sides of the torque converter, or when the torque increasing action of the torque converter is required. An automatic transmission equipped with a so-called lock-up mechanism has been put into practical use, which improves fuel efficiency by directly mechanically connecting the two.

On the other hand, in a torque converter that transmits torque from a pump on the engine side to a turbine on the transmission side via hydraulic oil, thermal energy is generated by slipping between the pump and the turbine outside the operating area of the lock-up mechanism.
This increases the temperature of the hydraulic oil, causing problems such as early deterioration of the hydraulic oil itself and deterioration of the sealing member.

By the way, to solve the problem of the increase in oil temperature in a torque converter, there is an invention disclosed in, for example, Japanese Unexamined Patent Publication No. 59-62766. This system regulates the line pressure in relation to the vehicle speed, and when the slippage in the torque converter is large, the line pressure is increased to increase the amount of oil 6, thereby increasing the cooling capacity and preventing the oil temperature from rising. It is. However, this method cools the hydraulic oil by increasing the cooling capacity when the oil temperature rises, but does not prevent the slippage itself in the torque converter, which is the cause of the oil temperature rise, and does not prevent the line pressure from increasing. This causes problems such as an increase in shift shock and an increase in drive loss of the oil pump.

(Object of the Invention) The present invention addresses the above-mentioned problems in automatic transmissions.In an automatic transmission equipped with a torque converter having a lock-up mechanism, when the temperature of hydraulic fluid becomes high, torque By expanding the lock-up operating range of the converter, the area where the torque converter slips, which causes oil temperature rise, is reduced, thereby suppressing the rise in oil temperature and solving problems such as early deterioration of hydraulic oil and seal members. The purpose is to prevent this from happening.

(Structure of the Invention) The lock-up control device for an automatic transmission according to the present invention is characterized in that it is structured as follows in order to achieve the above object.

That is, as shown in FIG. 1, a torque converter D provided between an output shaft B of an engine A and a transmission gear mechanism C;
Based on a lock-up means E that directly connects the torque converter D, a speed signal from a speed sensor F that detects vehicle speed, turbine rotational speed, etc., and an engine load signal from a load sensor G that detects throttle opening, etc. Lock-up area lii! which sets the operating area of the lock-up means E! In an automatic transmission I having a setting means,
An oil temperature detection means J detects the temperature of the hydraulic oil in the torque converter D or the automatic transmission I, and when the temperature of the hydraulic oil becomes high in response to a signal from the oil temperature detection means J, the lock-up is activated. Lockup area changing means for expanding the lockup operation area set by the area setting means H is provided. According to such a configuration, when the oil temperature is normal, the lockup means E operates within a predetermined lockup operation range based on speed signals such as vehicle speed and turbine rotational speed, and engine load signals such as throttle opening. Then, the torque converter D becomes directly connected, but when the temperature of the hydraulic oil becomes high, the lockup region changing means K expands the lockup operation region set by the lockup region setting means H. As a result, the lock-up means E operates over a wider range, narrowing the area in which the torque converter slips, which is the cause of an increase in oil temperature, and as a result, suppressing the increase in oil temperature. .

(Effects of the Invention) According to the above configuration, when the temperature of the hydraulic oil becomes high, the lock-up means operates in a region where the lock-up means normally does not operate. This prevents the oil temperature from rising and quickly lowers the oil temperature. This prevents deterioration of the seal member due to the high temperature of the hydraulic oil, and also prevents early deterioration of the hydraulic oil itself.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

First, an example of the mechanical structure and hydraulic control circuit of an automatic transmission to which this embodiment is applied will be explained with reference to FIG. 2. This automatic transmission 1 includes a torque converter 10, a multi-speed gear mechanism 20, and It is composed of an overdrive speed change gear 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 to face the pump 13, and the pump 13. The stator 15 is disposed between the turbine 14 and the turbine 14, and an output shaft 16 is coupled to the turbine 14. Further, a lock-up clutch 17 is provided between the output shaft 16 and the case 12. This lock-up clutch 1.7 is constantly pressed in the engagement direction by the pressure of the hydraulic oil circulating within the torque converter 10, and is released when release hydraulic 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. The input shaft 26 to this multi-speed gear mechanism 20 is
It is configured to be connected to the connecting shaft 25 through the front clutch 27 and to the ring gear 29 of the front planetary gear mechanism 21 through the rear clutch 28. A second brake 31 is provided between the sun gear 23, 24 and the transmission case 30 in .22. 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 between the binion carrier 35 of the rear planetary gear mechanism 22 and the transmission case 30. has a low reverse brake 36
A one-way clutch 37 and a one-way clutch 37 are respectively provided.

On the other hand, in the overdrive speed change gear mechanism 40, a tornion 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 to the output shaft 16 of the torque converter 10.
and 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 26 to the multi-speed gear mechanism 20.

The multi-speed gear mechanism 20 having the above-mentioned configuration is conventionally known, and is provided between the input shaft 26 and the output shaft 34 by selectively operating the clutches 27, 28 and the brakes 31, 36.
gear ratio, and one reverse gear. Further, the overdrive speed change gear mechanism 40 is configured to operate the torque converter 10 when the clutch 44 is engaged and the brake 45 is released.
The output shaft 16 of the multi-speed gear mechanism 20 is directly connected to the input shaft 26 of the multi-speed gear mechanism 20, and the clutch 44 is released and the brake 4 is
When 5 is fastened, the shaft 16.26 is overdrive coupled.

Next, the hydraulic control circuit 50 of the automatic transmission will be explained.

Hydraulic oil 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, R.

It has a range of N, D, 2.1, and D, 2. The main line 52 is connected to the boat a at the lunge. This boat a communicates with the actuator 28a of the rear clutch 28 through a line 55, and thus the
．． In each forward range of No. 1, the rear clutch 28 is always maintained in an engaged state.

Moreover, the boat a is the first boat. Second. Third. It communicates with fourth control lines 56.57, 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. The drain lines are 66 and 67 respectively.
．． 68, 69 are branched and these drain lines 6
6 to 69 respectively open and close. Second. Third. A fourth solenoid 71°72.73.74 is provided. When these solenoids 71-74 are OFF, the drain lines 66-69 are released and the pressure in the corresponding control lines 56-59 is zero, but when they are ON, the drain lines 66-69 are released.
By closing 69 and increasing the pressure in the control lines 56-59, the above 1-2 shift valve 61.2-3 shift valve 6
2.3-4 Move the spools 61a, 62a, 63a, and 64a of the shift valve 63 and lock-up valve 64 from the positions shown in the figure by arrows (a), (b), (c), and (d), respectively.
move in the direction.

The boat a in the select valve 54 also reaches the 1-2 shift valve 61 via a line 76 branched from the line 55, and the spool 61a is moved in the direction (A) by the hydraulic oil from the first control line 56. When moved to line 77, it also connects to second lock valve 78.
It is connected via a line 79 to the engagement side boat 31a' of the actuator 31a of the second brake 31. As a result, hydraulic oil is supplied to the boat 31a', and the second brake 31 is engaged.

Here, in the D range, the second lock valve 78 is supplied with hydraulic oil from both boats b and C of the select valve 54 via lines 80.81, and is connected to the lines 77.79 as shown in the figure. However, in the 2nd range where boat C is closed, hydraulic oil is supplied only from boat B, and spool 78a moves downward to connect lines 80 and 79.

Therefore, in the 2nd range, the second brake 31 is
-2 It will be fastened regardless of the state of the shift valve 61.

Also, in the D range, there is a bow 1- connected to the main line 52.
C is led to the 2-3 shift valve 62 by the line 81 via the one-way throttle valve 82. When the spool 62a of the 2-3 shift valve 62 is moved in the (b) direction by the hydraulic oil 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 The other boat reaches the release side boat 31a'' of the actuator 31a of the second brake 31, and the other reaches the actuator 27a of the front clutch 27.Thereby, the boats 1 to 318'' and the actuator 27
Hydraulic oil is supplied to a, the second brake 31 is released, and the front clutch 27 is engaged.

In addition, in the lunge, the boat d of the L left valve 54 is connected to the main line 52, and the hydraulic oil is guided to the 1-2 shift valve 61 through the line 86, and the spool 61a of the valve 61 is located at the position shown in the figure. Line 87
to the actuator 36a of the low reverse brake 36. As a result, the low reverse brake 36 is engaged.

Furthermore, in the R range, along with the boat d, the boat e
is in communication with the main line 52, so that hydraulic oil is guided to the 2-3 shift valve 62 by line 88, and also via the line 83 and line 84, 85 when the spool 62a of the valve 62 is in the position shown. 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 27 is engaged together with the low reverse brake 36. 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 458' of the actuator 45a of the overdrive brake 45. The line 89 led to the 3-4 shift valve 63 further leads to lines 91 and 92 when the spool 63a of the valve 63 is in the position shown, and one line 91 connects to the actuator 44a of the direct coupling clutch 44. , the other line 92 reaches the release side boat 458'' of the overdrive brake actuator 45a. Therefore, the 3-4 shift valve 63
When in the state shown in the figure, both boats 4 on the engagement side and the release side of the overdrive brake actuator 45a
53'.

Hydraulic oil is supplied to 45 a #, the overdrive brake 45 is released, and the direct coupling clutch 44 is engaged. Then, when the spool 63a of the 3-4 shift valve 63 is moved in the direction (c) by the hydraulic oil from the third control line 58, the lines 91 and 92 are drained, thereby releasing the direct coupling clutch 44 and Overdrive brake 45 is engaged.

Furthermore, hydraulic oil 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. The spool 6 in the valve 64
4a is in the illustrated position, the line 94 leads into the torque converter 10, and the torque converter 10
The inner lock-up clutch 17 is disengaged. Then, when the spool 64a of the lock-up valve 64 is moved in the (d) direction by the hydraulic oil from the fourth control line 59, the line 94 is drained, and the lock-up clutch 17 is activated within the torque converter 10. Fastened hydraulically.

In addition to the above configuration, this hydraulic control circuit 50 includes a cutback valve 95 that stabilizes the hydraulic 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 intake negative pressure, and a throttle backup valve 9 that assists the throttle valve 96.
7 is provided.

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 clutch in each range,
1. The relationship between the operating state of the brakes and the gears is explained separately. Second
．． It is shown in Table 3.

(Hereinafter, blank spaces) Table 1 Table 2 Next, the electric control circuit of the automatic transmission 1 will be explained using FIG. 3.

As shown in FIG. 3, this control circuit 100 is provided with a speed change control circuit 101 and a lock-up control circuit 102, and these circuits 101 and 102 include a turbine for detecting the rotation speed of the turbine 14 in the torque converter 10. Turbine rotation signal from rotation sensor 1038. a and
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 shift control circuit 101 and the lock-up control circuit 102 perform a shift and lock-up map preset according to the turbine rotational speed and the throttle opening as shown in FIG. Therefore, it is determined whether the operating state is in a shift-up zone, a shift-down zone, or a hold zone, and whether it is in a lock-up activation or release zone, and depending on the determination result, A shift control signal C and a lock-up control signal d are 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 gear stage to be set according to Table 1 above, and the automatic transmission 1 is operated to perform the required shift according to the operating range. set in stages,
Also, the fourth solenoid 74 is turned ON and OFF according to Table 2.
The lockup is then activated or released depending on the operating range.

In addition to the above configuration, the lock-up control circuit 102 is configured to receive an oil temperature signal e from an oil temperature sensor 105 that detects the temperature of the hydraulic oil in the torque converter 10. When the oil temperature within 10 becomes higher than the set temperature, the dotted line x' in Figure 4
, y', the lines for setting the lock-up activation and release zones are shifted to the lower turbine rotation speed side than the normal lines x and . Therefore,
When the oil temperature of the torque converter 10 is high, the lockup control circuit 102 determines whether the lockup is activated or released based on the lockup map indicated by dotted lines x/, y/.

Here, the specific mounting state of the oil temperature sensor 105 will be explained in the fifth section.
To explain with reference to Figure 7, automatic gear shifting t! On the external upper surface of the transmission case 30 at 11, a mounting bracket 110 having an oil passage 110a penetrated therethrough is connected to three bolts 111...111.
A flexible hose 1 for taking out hydraulic oil is connected to one end of the oil passage 110a through a connector 112 inside the torque converter 10.
A pipe 114 leading to an oil cooler (not shown) is connected to the other end of the oil passage 110a. Then, the temperature sensing portion 10 at the tip is attached to the mounting bracket 110.
The oil temperature sensor 1
05 is installed. Therefore, torque converter 1
The hydraulic oil that has circulated through the oil passage 110 and reached a high temperature is supplied from the flexible hose 113 to the oil cooler through the oil passage 110a of the mounting bracket 110 and the pipe 114, but when passing through the oil passage 110a, The oil temperature sensor 105 detects the temperature.

The control circuit 100 that performs the above-described control can be configured by, for example, a microcomputer, and in that case, the control circuit 1oo operates according to the flowcharts shown in FIGS. 8 and subsequent figures. Next, this operation will be explained.

Left 4 > Hole l First, to explain the flowchart of the main control shown in FIG. Make sure that the range you are on is not the N range or P range. If the shift position is set to lunge, execute steps A4-88 from step A3, first release the lockup, and make sure that the engine rotation is overrun when downshifting to 1st gear. After confirming by calculation whether or not there is an overrun, the gear is shifted to 2nd gear if an overrun occurs, and to 1st gear if an overrun does not occur. If the gear is set to the 2nd range, steps A1o and A1t are executed through steps A3 to A9, and the lockup is released, and then the gear is shifted to the second gear.

On the other hand, when the D range is set, shift-up control, shift-down control, and lock-up control, which will be described later, are performed in steps A12 to A14.

27h7y7 star 1 - Next, the shift up control in step A12 in the above main control will be explained. As shown in FIG. 9,
In this control, first, in step B1, it is checked whether the transmission gear mechanism 20.40 shown in FIG. . If the speed is other than 4th, follow steps 82 to B5 to read the current throttle opening, read out the set turbine rotation speed Tmap corresponding to the read throttle opening from the preset and stored shift-up map, and Read the actual turbine rotation speed (C1) and compare it with the set turbine rotation speed Tmap. Here, the shift-up map is a map in which the set turbine rotational speed Tmap corresponding to each throttle opening is stored as a shift-up line Mu as shown in FIG. This corresponds to the boundary line X between the up zone and the hold zone. When the actual turbine rotation speed T is larger than the set turbine rotation speed Tl1ap, that is, when the operating region is in the shift-up zone shown in FIG. 4 or 10, the shift-up flag F
If 1 is "On," step B5 to step 86~
According to B8, the above-mentioned flag F, 1 is set to 1'', and the gear stage is shifted up by one step.When the above-mentioned shift-up flag F1 is 1'', it indicates that a shift-up signal has been output, and this causes the shift-up. As the action takes place,
When it is determined in step B6 that the flag F1 is set to "1", the control is temporarily terminated without upshifting again. Also, step B above
5, the actual turbine rotation speed T is the set turbine rotation speed Tm
When it is determined that it is smaller than ap, steps 89 to an
Accordingly, a new shift up line Mu' shown by a broken line in FIG. 10 is set by multiplying the set turbine rotation speed Tmap by 0.8.

Then, the shift-up flag F1 is reset to OIt only when the actual lower turbine rotation speed becomes smaller than the new set turbine rotation speed T map corresponding to this line f, 4 u l due to the shift-up operation, and the shift-up is performed. The operation is complete. The purpose of the control in steps 89 to B1t is to form a hysteresis zone and prevent so-called chattering, in which the speed change is performed in a complicated manner when the turbine rotational speed is near the shift-up line MU.

27h>11- Further, the downshift control in step A13 of FIG. 8 is executed as follows according to the flowchart of FIG. 11.

First, in step C1, it is confirmed that the transmission gear mechanism 20.40 is in a gear other than 1st gear, that is, in which downshifting is possible, and then the actual throttle opening is read in accordance with steps 02 to c5. The set turbine rotation speed Tmap corresponding to the throttle opening at that time is read out from the shift down Ii1Md set in the shift down map as shown in the figure, and this is compared with the actual turbine rotation speed Tmap. Here, the shift down line Md is the fourth
This corresponds to the boundary line Y between the hold zone and the downshift zone shown in the figure. Then, when the actual turbine rotation speed T map is smaller than the set turbine rotation speed T map, 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, 7
When the lag F2 is set to "1", the control is temporarily terminated. Then, when the actual turbine rotation speed Tmap becomes larger than the set turbine rotation speed Tmap in step C5, the set turbine rotation speed Tmap is multiplied by 110°8 according to steps 09 to C11, as shown by the broken line in FIG. A new shift down line Md' is formed, and the actual turbine rotational speed Tll1ap is compared with a new set rotational speed Tll1ap corresponding to this line Md'. Then, when T>Tmap is established as a result of the downshift operation, the downshift flag F2 is reset to 1101+, and the downshift operation is completed.

Lock-up control Furthermore, the lock-up control shown in step A14 in the main control of FIG. 8 is executed according to the flowchart shown in FIG.

In this control, according to steps D1 to D5, the throttle opening degree is read, and the lock-up release line M set on the lock-up map as shown in FIG.
When the oil temperature in the torque converter 10 has not reached the predetermined temperature, read the set turbine rotation speed Tmap corresponding to the throttle opening at that time while off, and if the oil temperature in the torque converter 10 has not reached the predetermined temperature, this set turbine rotation speed Tmap and the actual turbine rotation speed T
Compare with. When the actual turbine rotation speed T is smaller than the set turbine rotation speed Tmap, that is, when it is in the lock-up release zone (1) shown in FIG. 14, step D6 is performed.
to release the lockup.

The actual turbine rotation speed T is equal to the lock-up release line Mo.
When it is larger than the set turbine rotation speed Tmap corresponding to n, in step D7, the lockup operation line M is set by providing a hysteresis zone of a predetermined width on the high turbine rotation speed side of the lockup release line MOff shown in FIG.
Read the set turbine rotation speed T map corresponding to on. Then, in steps DB and D9, when the oil temperature in the torque converter 10 has not reached a predetermined temperature, this set turbine rotation speed Tl1lap and the actual turbine rotation speed T are compared. And when T > T map,
That is, when in the lock-up operation zone (2) shown in FIG. 14, the lock-up operation is controlled in step D10.

However, when the oil temperature in the torque converter 10 is higher than a predetermined temperature, that is, when the oil temperature is high, step D1. D2
After reading the throttle opening and reading the set turbine rotation speed Tmap corresponding to the throttle opening at that time from the lock-up release line Moff shown in FIG. 14, it is determined in step D3 that the inside of the torque converter 10 is in a high oil temperature state. After determining that, in step D11, a predetermined rotation speed TO is subtracted from the set turbine rotation speed T map to create a new lock-up release line M shown by a dotted line in FIG.
oH' is formed. Then, in step D5, the actual turbine rotation speed T and the new set rotation speed T map corresponding to this lIMOff' are compared, and when the actual turbine rotation speed T is smaller than this new set rotation speed T map, That is, the lockup is released in step D6 only when the lockup is in the new lockup release zone (1') shown in FIG.

A new set turbine rotation speed T at which the actual turbine rotation speed T corresponds to the above-mentioned new lock-up release line MOf'
If it is larger than map, then in step D7, the set turbine rotation speed Tmap corresponding to the throttle opening at that time is read from the lockup operation line Mon shown in FIG. In this case, since the oil temperature inside the torque converter 10 is high, steps D8 to D12 are executed, and a predetermined rotation speed To is subtracted from the set turbine rotation speed T map to obtain a new value as shown by the dotted line in FIG. A lockup operating line lyl on' is formed. Then, in step D9, the actual turbine rotation speed T and this line M o
The actual turbine rotation speed T is compared with the new set rotation speed Tmaρ corresponding to n'.
Step D1o is performed only when the lockup operation zone (2') shown in FIG.
The lock-up operation is controlled by.

In this way, when the temperature of the hydraulic oil is high, the lock-up operating range is expanded to the low turbine rotation speed side by a fixed turbine rotation speed of 10 minutes. Therefore, in this expanded lockup operating region, the torque converter 1
When the oil temperature rises due to the zero stagnation, the lock-up clutch 17 is engaged to eliminate the stagnation in the torque converter 10, thereby lowering the temperature of the hydraulic oil.

Next, another embodiment of the present invention shown in FIGS. 15 and 16 will be described.

Although the mechanical structure and hydraulic control circuit of the automatic transmission 1 are the same in this embodiment, as shown in FIG. 15, the lock-up control circuit 102' includes a turbine rotation sensor 103', Throttle opening sensor 104
' and an oil temperature sensor 105', a mode changeover switch 106' is connected to manually switch between a power mode for powerful driving and an economy mode for economical driving. Further, the lock-up control circuit 102'
Mode determination circuit 107' and lock-up determination circuit 10
8' and a lock-up solenoid drive circuit 109', which receives the oil temperature signal @e' from the oil temperature sensor 1.5' and the mode switching signal f from the mode switching switch 106'.
' is input to the mode determination circuit 107', and the mode determination signal Q' from the mode determination circuit 107' is inputted to the mode determination circuit 107'.
The lock-up determination circuit 108 receives the turbine rotation signal a' from the turbine rotation sensor 103' and the throttle opening signal b' from the throttle opening sensor 104'.
’. Furthermore, the lockup signal h' from the lockup determination circuit 108'
is input to the lock-up solenoid drive circuit 109', and the lock-up solenoid 74 shown in FIG. 2.3 is operated by the signal d' output from the lock-up solenoid drive circuit 109'.

The mode determination circuit 107' includes a mode changeover switch 1
When 06' is operated to power mode, a mode is set as a lock-up map in which lock-up is activated and released in the high turbine rotation range shown in FIG. 16 (1). This maximizes the torque increasing effect of the torque converter and enables powerful driving. Also,
If the economy mode is selected, a mode is set in which lock-up is activated and released in the middle turbine rotation range as shown in Figure 16 (2), thereby expanding the direct connection area of the torque converter and improving fuel efficiency. become.

However, the oil temperature sensor 105' is connected to the mode determination circuit 107'.
When an oil temperature signal e' indicating a high oil temperature is input from
The determination circuit 107' sets a high oil temperature mode in which lock-up is activated and released in a lower turbine rotation range as shown in FIG. 16(3). As a result, when the temperature of the hydraulic oil is high, the lock-up region is further expanded to the lower turbine speed side, and the lock-up clutch is engaged in this expanded region, preventing the oil temperature from increasing due to slipping of the torque converter. This will be prevented.

Note that when the lock-up clutch is engaged due to a high oil temperature, the lock-up clutch is released when a predetermined time has elapsed from the time of engagement or when the oil temperature has fallen below a predetermined temperature.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the present invention, FIGS. 2 to 14 show a first embodiment of the invention, FIG. 2 is a configuration diagram showing the mechanical structure and hydraulic control circuit of an automatic transmission, and FIG. Figure 3 is a configuration diagram showing the electric control circuit, Figure 4 is a characteristic diagram showing control characteristics, Figure 5 is a plan view of the automatic transmission showing the position of the oil temperature sensor, and Figure 6 is an enlarged plan view of its main parts. Figure, Figure 7 is Figure 6 ■π-
■A sectional view taken along the line, Figure 8.9.11.13 is a flowchart showing the operation, Figures 10' and 12.14 are shift-up maps, shift-down maps, and lock-up maps used for control, respectively. 15 and 16 show a second embodiment of the present invention. FIG. 15 is a block diagram showing the configuration of an electric control circuit, and FIG. 16 is a lock-up map used for control. 1-... automatic transmission, 2... engine, 3... engine output shaft, 10... torque converter, 17...
Lock-up means (lock-up clutch), 20.4
0... Speed change gear mechanism, 103, 103'... Turbine rotation sensor, 104.104'... Throttle opening sensor, 105.105'... Oil temperature detection means (oil temperature sensor), H.・Lockup area setting means, K・
...Lockup area changing means. Figure 3 Figure 41I Turbi ``JgJ-ζ song → crystal Figure 6 3゜ 5ai 711I 111! n”)-Mo-do) (ヱ, Konomi mode) (!15self; Supervision mode) → High → High → High

Claims (1)

[Claims] (1) A torque converter provided between the output shaft of the engine and the variable speed gear mechanism, a lock-up means for directly connecting the torque converter, and engine speed signals such as vehicle speed and turbine rotation speed, and throttle opening, etc. A lockup control device for an automatic transmission, comprising lockup region setting means for setting an operating region of the lockup means based on a load signal, and oil temperature detection means for detecting the oil temperature of the torque converter; Lockup region changing means is provided for expanding the lockup operating region set by the lockup region setting means when the oil temperature of the torque converter becomes high in response to a signal from the oil temperature detection means. A lock-up control device for an automatic transmission characterized by: