JP3385923B2 - Control device for automatic transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling an automatic transmission for a vehicle, and more particularly to a control device for setting a gear by controlling on / off of a solenoid valve.

[0002]

2. Description of the Related Art An automatic transmission for a vehicle supplies and discharges hydraulic pressure to and from friction engagement devices such as clutches and brakes to control the engagement and disengagement states of the frictional engagement devices so that an input shaft is connected to an output shaft. It is configured to change the transmission path of the reaching torque, that is, to change the gear ratio. The friction GoSo location
Hydraulic control for engaging or releasing has recently
It is becoming more common to use solenoid valves. That is, a solenoid valve that is turned on and off and outputs a signal pressure is connected to each of a plurality of shift valves that change an oil passage for the friction engagement device, and further, an engine brake state is set. By providing other solenoid valves and controlling these solenoid valves to turn on or off as appropriate,
A predetermined forward speed is set and the engine brake is applied at any speed. Therefore, in this type of automatic transmission, the gear position is uniquely determined by the combination of ON / OFF of those solenoid valves.

On the other hand, in an automatic transmission that uses a solenoid valve to perform shift control, an electric gear failure or mechanical failure of a solenoid valve may cause a situation in which an intended gear position is not set or an unintended gear shift. May be executed. Therefore, for example, JP-A-5-6
In the invention described in Japanese Patent No. 0210, for a combination of ON / OFF of a solenoid valve that sets a predetermined shift speed, a solenoid valve is turned on for effecting engine braking at a shift speed lower than that. -The off combination is a combination in which the two solenoid valves have different on / off states.

That is, it is unlikely that two solenoid valves will fail at the same time. Therefore, in the above-described automatic transmission, it is possible to prevent the downshift to the gear stage in which the engine braking is effective due to the failure of the solenoid valve.

[0005]

By the way, in an automatic transmission for a vehicle, in addition to gear shifting by engagement / disengagement of a frictional engagement device, various types of hydraulic pressure control during gear shifting and hydraulic pressure control according to a gear shifting pattern are possible. The hydraulic pressure is controlled. Further, in order to reduce the size and weight of the control device, the control may be performed by diverting another control system without performing the control by each independent control system.

Therefore, like the conventional automatic transmission described above, from the viewpoint of fail-safe, the engine brake is applied at a combination of ON / OFF of the solenoid valve for setting a predetermined gear and a gear lower than that. When control is performed such that the on / off combination of the solenoid valves is a combination in which the on / off states of the two solenoid valves are different, inconvenience may occur at the time of setting one of the shift stages. For example, there are two kinds of combinations of on / off of the solenoid valve for setting a predetermined shift speed, and according to one of the combinations, the on / off of the solenoid valve for applying the engine brake at the low speed shift speed is set.
Two solenoid valves on / off for off combinations
Although the off state can be made different, in that combination, the engagement pressure of the friction engagement device that sets the predetermined shift speed is controlled to be low, and as a result, the torque capacity of the friction engagement device is reduced. There was a possibility of shortage.

The present invention has been made in view of the above circumstances, and excessive engine braking is effected due to the failure of the solenoid valve, or the torque capacity of the friction engagement device for setting the shift speed is insufficient. An object of the present invention is to provide a control device for an automatic transmission that can prevent such a situation as described above.

[0008]

In order to achieve the above-mentioned object, the invention described in claim 1 sets a plurality of shift speeds according to a combination of ON / OFF of a plurality of solenoid valves. At least two solenoids for a combination of on / off of a solenoid valve for setting any one of the shift stages for effecting engine braking at a shift speed lower than the shift stage. In the automatic transmission control device capable of selecting two combinations, one having a different on / off state of the valve and the other having a different on / off state of one solenoid valve, the predetermined condition is A condition satisfaction determining means for determining that the condition is satisfied, and the shift speed are set when the condition satisfaction determining means determines that the condition is satisfied. The on / off combination of the solenoid valves is set to be at least two solenoid valve on / off combinations with respect to the on / off combination of the solenoid valves for effecting engine braking at a speed lower than the gear. If the conditions are determined not to be met by the condition satisfaction determination means, a combination of ON / OFF of the solenoid valve for setting the gear is selected from the gears. to cause union different states of on and off of a single solenoid valve for the combination of the solenoid valve on and off for engine brake in the low speed side gear stage
It is a control device according to claim that a pattern setting unit that switches automatically. According to a second aspect of the present invention, in the first aspect of the invention, the condition is that the vehicle speed is equal to or higher than a predetermined reference vehicle speed, and the output shaft rotation speed of the automatic transmission is equal to or higher than a predetermined reference rotation speed. It is a control device characterized by being at least one of the following. Further, the invention of claim 3 is the invention of claim 2, wherein the reference vehicle speed or reference rotational speed for determining whether the condition is satisfied and the reference vehicle speed or reference rotational speed for determining that the condition is not satisfied. The control device is characterized in that hysteresis is set between and.

Therefore, according to the control device of the present invention,
When a preset condition such as a vehicle speed or an output shaft rotation speed being equal to or higher than a preset reference value is satisfied, a combination of ON / OFF of the solenoid valve for setting the shift stage is used as a low speed shift stage. There is a combination where the on / off state of at least two solenoid valves is different from the on / off combination for applying the engine brake.
Adopted dynamically . Therefore, in setting the shift speed, even if any one of the solenoid valves fails, it is possible to avoid shifting to a state where the engine braking is effective at the shift speed on the low speed side. It If the condition is not satisfied, the shift speed is changed depending on the combination of the on / off states of one solenoid valve that is different from the on / off combination of the solenoid valves that sets the shift speed on the low speed side where the engine brake works. The gear is set, but by adopting a condition that takes into consideration the obstacle when a shift to the state where the engine brake works at the low gear side occurs as a condition, a special discomfort due to the failure of the solenoid valve is avoided. can do.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described more specifically with reference to the drawings. First, a schematic configuration of an example of an automatic transmission targeted by the control device of the present invention will be described. Figure 4
Shows an automatic transmission 10 described in Japanese Unexamined Patent Publication No. 8-159263, and its mechanical parts include a sub transmission mechanism D having a front-end type overdrive configuration, a simple connection 3 and a forward movement 4 having a planetary gear train configuration. The main transmission mechanism M of the first reverse speed is combined with a fifth speed configuration, and this mechanism portion is connected to a torque converter T with a lockup clutch L.

The subtransmission mechanism D includes a one-way clutch (OWC) F-0 and a multi-plate clutch C-0 arranged in parallel with the sun gear S0, the carrier C0 and the ring gear R0.
And a multi-plate brake B-0 in series therewith. On the other hand, the main speed change mechanism M includes three gear units P1 of simple connection in which the speed change elements including the sun gears S1 to S3, the carriers C1 to C3, and the ring gears R1 to R3 are directly connected.
.About.P3, and related to the transmission elements of the gear units P1 to P3, multi-disc clutches C-1, C-2, band brake B-1, multi-disc brakes B-2 to B-4, one-way clutch (OWC). ) F-1 and F-2 are provided. In the figure, reference numeral SN1 indicates a C0 sensor for detecting the drum rotation of the clutch C-0, and SN2 indicates a C2 sensor for detecting the drum rotation of the clutch C-2. Further, although not shown, each clutch and brake is provided with a hydraulic servo composed of a piston / cylinder mechanism for engaging / disengaging the friction materials thereof.

As shown in FIG. 6, the automatic transmission 10 has a mechanical portion having the above-mentioned structure, a hydraulic control device 20 for controlling the torque converter and the lockup clutch, and a hydraulic source for the hydraulic control device 20 incorporated in the mechanical portion. An oil pump (not shown) is provided. In the vehicle-mounted state, the automatic transmission 10 is connected to the engine E, and the hydraulic control device 20 of the automatic transmission 10 includes solenoid valves SL1 to SL4 and linear solenoid valves S incorporated therein.
The automatic shift control computer 30 is connected to the automatic shift control computer 30 via LN, SLT and SLU.
Is connected to various sensors 40 arranged in various parts of the vehicle including the engine E and the automatic transmission 10 and an engine control computer 50.

In the automatic transmission 10, the output torque of the engine E shown in FIG. 6 is transmitted to the input shaft N of the auxiliary transmission mechanism D via the torque converter T shown in FIG. Under the control of the hydraulic control device 20, the torque of the input shaft N engages the clutch C-0 to directly connect the sub transmission mechanism D and engages the clutch C-1 of the main transmission mechanism M. , When the other frictional engagement elements are all released, the one-way clutch F-2 is applied to the gear unit P3 to prevent reverse rotation of the ring gear R3, and the carrier C3
Is output to the output shaft U as the first speed rotation.

Next, the second speed is achieved when the auxiliary transmission mechanism D is directly connected and the clutch C-1 and the brake B-3 are engaged, and at this time, the torque input to the gear unit P2 is: The carrier C1 of the gear unit P1 is output as a reaction force element to the carrier C2 of the gear unit P2 and the ring gear R1 of the gear unit P1 directly connected to the carrier C2, and is output to the output shaft U as the second speed rotation.

Similarly, the third speed is achieved by directly connecting the auxiliary transmission mechanism D, engaging the clutch C-1 and the brake B-2, and releasing the other frictional engagement elements. At this time, the torque input to the ring gear R2 of the gear unit P2 is output from the output shaft U via the carrier C2 as the third speed rotation using the sun gear S2 as a reaction element.

Further, in the fourth speed, similarly, the auxiliary transmission mechanism D
Is directly connected and is achieved by engaging both the clutch C-1 and the clutch C-2. At this time, since the gear unit P2 is directly connected to the ring gear R2 and the sun gear S2, the input torque is output as it is. In the fifth speed, the main transmission mechanism M is in a state similar to the fourth speed described above, and the clutch C-0 of the auxiliary transmission mechanism D is released and the brake B-0 is engaged in response to this. By fixing the sun gear S0, the auxiliary transmission mechanism D
Is achieved by increasing the speed of rotation.

At the reverse speed, the auxiliary transmission mechanism D is set to the above state, and the clutch C-2 and the brake B- of the main transmission mechanism M are set.
It is achieved by engaging 4 and. At this time, the torque input to the sun gear S2 of the gear unit P2 is output as reverse rotation of the carriers C2 and C3 of the gear units P2 and P3 having the ring gear R3 as a reaction force element.

The relationship between the engagement and disengagement of each friction engagement element and the one-way clutch in each of the above-mentioned shift speeds is shown in FIG. 5 as an operation chart. In the figure, the meanings of symbols such as O and X are as described in the remarks column of FIG.

Brake B in the above automatic transmission 10
The circuit shown in FIG. 2 is provided as a hydraulic circuit for controlling −2 and B-3. Specifically, the brake B-
3, a hydraulic servo 28 for controlling engagement / release of the brake B-3, an oil passage 201 connected to the hydraulic servo 28 for supplying / discharging hydraulic pressure to / from the hydraulic servo 28, and an oil passage 201.
A B-3 control valve 25 as a pressure regulating valve and a linear solenoid valve SLU for applying a signal pressure to the B-3 control valve 25 are provided.

The oil passage 201 includes a first oil passage 201d for supplying hydraulic pressure to the B-3 control valve 25, and a B-3 oil passage.
It has second oil passages 201e and 201f for supplying the hydraulic pressure from the control valve 25 to the hydraulic servo 28. The B-3 control valve 25 includes a valve body 250,
An input port 254 connected to the first oil passage 201d,
An output port 255 connected to the second oil passage 201e,
And a discharge port 257 connected to the discharge oil passage EX.

As shown enlarged in FIG. 3, the valve body 250
Is the first pressure receiving surface A1 to which the feedback pressure of the second oil passage 201e is applied in the direction to connect the output port 255 and the discharge port 257, and the signal pressure (PSLU) is output to the output port 255 and the discharge port 257. And a second pressure receiving surface A2 applied in a direction for communicating with each other and having a diameter larger than that of the second pressure receiving surface A2, and a signal pressure (PSLU) is applied in a direction for communicating between the output port 255 and the input port 254. And a third pressure receiving surface A3. The linear solenoid valve SLU constantly applies the signal pressure (PSLU) to the third pressure receiving surface A3 and selectively applies the signal pressure (PSLU) to the second pressure receiving surface A2.

B-3 Valve body 25 of control valve 25
Reference numeral 0 denotes a spool 251 having a first pressure receiving surface A1 and a plunger 253 having second and third pressure receiving surfaces A2 and A3 coaxially arranged on the spool 251. The spool 251 and the plunger 253 A spring 258 is disposed between the spring 258 and the spring 258 is urged to separate the spool 251 and the plunger 253 from each other.

In FIG. 2, a brake B-3 is a friction engagement element for achieving the second speed of the automatic transmission 10. When the brake B-3 is released to achieve the third speed, the brake B-3 is used. B-2 is engaged. The second pressure receiving surface A2
A B-2 release valve 24 is provided as a switching valve for switching between application and interruption of the signal pressure (PSLU) to the B-
The 2 release valve 24 applies the signal pressure (PSLU) to the second pressure receiving surface A2 at least during the shift from the second speed to the third speed, and after the shift is completed, the signal pressure (PSLU) to the second pressure receiving surface A2 is changed.
SLU).

The brake B-2, which is engaged when the brake B-3 is released, controls the engagement / release of the brake B-2.
9, the valve body 250 of the B-3 control valve 25
Has a fourth pressure receiving surface A4 to which the engagement pressure to the hydraulic servo 29 is applied in the direction in which the output port 255 and the discharge port 257 are communicated with each other.

Including the above-mentioned elements, the circuit parts directly involved in the hydraulic pressure and supply / discharge of the hydraulic servos 28, 29 for engaging / disengaging the friction materials of the brake B-3 and the brake B-2 are 1 -2 shift valve 21, 2-3 shift valve 2
2, 3-4 shift valve 23, B-2 release valve 2
4, B-3 control valve 25, relay valve 26
And a B-2 accumulator 27,
These are the solenoid valves SL1 to SL4 shown in FIG. 5 for switching the shift valves, the lockup linear solenoid valve SLU, the B-2 accumulator 27 and the accumulator control valve linear solenoid valve SLN for controlling the back pressure thereof, and the engine load. Linear solenoid valve SLT that outputs a corresponding control signal
Controlled by etc. The hydraulic pressure for adjusting the B-3 brake hydraulic pressure to the B-3 control valve 25 is supplied via the 1-2 shift valve 21. Further, a relay valve 26 controlled by the hydraulic pressure from the brake B-2 is arranged between the B-3 control valve 25 and the brake B-3.

The connection relationship between each valve and the oil passage will be described in more detail. The D range pressure oil passage 201 connected to a manual valve (not shown) branches via the 1-2 shift valve 21, and one oil passage 201a The oil passage 201h is connected to the relay valve 26 via the 2-3 shift valve 22 and is connected to the oil passage 201f of the brake B-3 via the relay valve 26. The other branched oil passage 2
01b is a 3-4 shift valve 23, oil passage 201c, B
The -2 release valve 24 and the oil passage 201d are connected to the input port 254 of the B-3 control valve 25, and the B-3 control valve 25 is connected to the relay valve 26 via the oil passage 201e.

The other D-range pressure oil passage 202 connected to the manual valve is branched via the 2-3 shift valve 22, and one oil passage 202a is connected to the oil passage 204 of the brake B-2 via the orifice. There is. This oil passage 204
Is connected to the oil passage 202a via the B-2 release valve 24 and the check valve, and is also connected to the accumulator 27 via the orifice. The other branched oil passage 202b is connected to the hydraulic servo 29 of the clutch C-2 via the 3-4 shift valve 23.

The 3-4 shift valve 23 applies the signal pressure (PSL3) of the solenoid valve SL3 to the spool end of the B-2 release valve 24, in addition to connecting and disconnecting the two oil passages 201b and 202b. For this purpose, the solenoid valve signal pressure oil passage 205 is connected to the B-2 release valve 24.

The B-2 release valve 24 is a brake B.
-2 is provided to form a bypass circuit that speeds up the drainage of the hydraulic pressure of the accumulator 27 at the end of release, and the spool 241 to which the elastic force of the spring is loaded is provided.
And the signal pressure (PSL3) of the solenoid valve SL3 is passed through the 3-4 shift valve 23 to the spool 241.
Of the bypass oil passage 202d to and from the brake B-2 oil passage 204, and to the input port 254 of the B-3 control valve 25 of the D range pressure oil passages 201c and 201d. Switching of communication, application of signal pressure (PLSU) to the pressure receiving surface A2 of the B-3 control valve 25 through the oil passage 206, and oil passage 206
Switch the drain connection of. Therefore, the D range pressure (PD) can be supplied in parallel to the input port 254 of the B-3 control valve 25 from the two oil passages 201a and 201b via the B-2 release valve 24.

The B-3 control valve 25 receives the feedback pressure applied to the end of the spool 251 through the feedback pressure input port 256, and the spool 251 receives the feedback pressure.
The input port 254 is opened and closed on one side of the two lands provided on the other side, and the drain port 257 is opened and closed on the other side to regulate the hydraulic pressure of the oil passage 201e connected to the output port 255, and is coaxial with the spool 251. The plunger 252 disposed on the end surface has a 2-3 shift valve 2 on its end face.
Oil passage 2 connected to the oil passage 204 of the brake B-2 via the oil passage 2
The engagement pressure of the brake B-2 of 04a is applied to press the spool 251. The B-3 control valve 25 includes the spool 2 as described above.
Plunger 2 for pressing 51 through spring 258
53 is provided on the side opposite to the plunger 252,
The solenoid signal pressure (PSLU) can be applied to and released from one end surface of the plunger 253 at all times and the other end surface through an oil passage 206 passing through the B-2 release valve 24.

The relay valve 26 is a spring-loaded spool type switching valve. The B-2 brake pressure of the oil passage 204 is applied to the spring-loaded side spool end, and the line is applied to the other spool end. Pressure (PL) is applied oppositely, and the oil passage 201f and the oil passage 2 of the brake B-3 are applied.
It is configured to switch the communication between 01e and the oil passage 201h.

The operation status of the circuit configured as described above will be described below with reference to the circuit diagram of FIG. 2 and the time charts of FIGS. (1) 1 → 2 shift control operation (see FIG. 7) When the electronic control unit determines that 1 → 2 shift, the solenoid valve SL3 is switched from off to on and B-2
The release valve 24 is set to the left half position shown in FIG.
As a result, the signal pressure (PSLU) is applied via the B-2 release valve 24 and the oil passage 206, and the B-3 control valve 25 enters the small control gain state. Next, the 1-2 shift valve 21 is switched to the second speed state,
D range pressure (PD) via manual valve (not shown), oil passage 201, 2-3 shift valve 22, oil passage 201g, B-2 release valve 24 and oil passage 201d
Is supplied to the hydraulic servo 28 via the relay valve 26 and the oil passage 201f as the B-3 brake pressure via the B-3 control valve 25, while the C-0 clutch pressure is drained. After that, the B-3 control valve 25 directly controls the B-3 brake pressure in the sections a, b, and c shown in FIG. Specifically, during the piston stroke of the hydraulic servo (section a), the elastic force of the return spring 258 sets the hydraulic pressure level for fast fill.
In the section b, the output pressure (PSLU) of the linear solenoid valve SLU is increased at a predetermined increase rate to cause a rotational change. In section c, the linear solenoid valve SLU is feedback-controlled according to the target rotation change. 1 → 2
When it is determined that the shift is completed (2nd synchronization), the solenoid valve SL3 is turned off to control the solenoid signal pressure (PSL).
3) is applied to switch the B-2 release valve 24 to the right half position shown in the figure, and the signal pressure (PSLU) on the pressure receiving surface A2 side of the plunger 253 of the B-3 control valve 25 is released to control the B-3 control. The valve 25 is set to a large gain, and another path 201 passing through the 1-2 shift valve 21
The D range pressure (PD) is continuously supplied to the hydraulic servo via the B-3 control valve 25 via the B-2 release valve 24 switched from c, and the B-3 brake pressure is rapidly increased to the line pressure (PL). Raise and end the shift.
As a result, in the steady state of the second speed (2nd), the spool 251 is locked at the lowermost position in the figure while B-2.
The spool 241 of the release valve 24 is fixed at the lower position in the figure by supplying the signal pressure (PSL3) of the solenoid valve SL3. (2) 2 → 1 shift control operation (see FIG. 8) At the same time as shift determination, the output of the linear solenoid valve SLU is set to 100% to prepare for the drain control of the B-3 brake pressure. Next, the solenoid valve SL3 is switched from OFF to ON, the B-2 release valve 24 is brought to the position shown in the left half of the figure, and the B-3 control valve 25 is brought into a small gain state. After that, the linear solenoid valve SL
The output of U directly controls the drain of B-3 brake pressure. After the 1st speed (1st) is synchronized, the 1-2 shift valve 21 is switched to the 1st speed state, the supply of the B-3 brake pressure is cut off, and the C-0 exhaust valve is switched to the C-
Start supplying 0 clutch pressure. After determining the end of the 2 → 1 shift, the solenoid valve SL3 is switched from ON to OFF, the B-2 release valve 24 is returned to the position shown in the right half of the figure, and a large drain state of the B-2 brake pressure is secured. . (3) 2 → 3 shift control operation (see FIG. 9) Based on the shift determination, the 2-3 shift valve 22 is switched to the third speed side, and the D range pressure (PD) is changed via the 2-3 shift valve 22. Supply to the hydraulic servo of brake B-2. The B-3 control valve 25 adjusts the B-3 brake pressure to the required minimum pressure according to the increase of the B-2 brake pressure (section a). The inertia phase is feedback-controlled by controlling the back pressure of the B-2 accumulator 27 (section b). Further B-2 Accumulator 2
The pressure accumulation of No. 7 is completed, the relay valve 26 is switched, the oil passage for the brake B-3 is cut off, and the shift is completed.

In the control device in the above example, 2
→ A force that opposes the hydraulic pressure applied to the B-3 control valve 25 from the brake B-2, which is a frictional engagement element on the engagement side, by setting the B-3 control valve 25 to a large gain even during 3 shifts. Is ensured by increasing the pressure receiving area of the signal pressure (PSLU).

Therefore, in the above control device, the third pressure receiving surface A3 is made wider than the second pressure receiving surface A2, and the signal pressure (PSL
U) is applied in a direction in which the output port 255 and the input port 254 are communicated with each other. Therefore, when the hydraulic pressure is discharged from the hydraulic servo 28, the linear solenoid valve S
The signal pressure (PSLU) from the LU is applied to both the second pressure receiving surface A2 and the third pressure receiving surface A3, so that the signal pressure (PSLU) acts in a direction to connect the output port 255 and the input port 254. Since the discharge control of the hydraulic pressure is started from this state, it is possible to prevent the pressure drop due to the rapid communication between the output port 255 and the discharge port 257.
Moreover, since the signal pressure (PSLU) is applied to the second pressure receiving surface A2 as well, it is possible to control the hydraulic pressure discharge from the high hydraulic pressure with a high control accuracy with a small control gain.

In the automatic transmission 10 described above, the brake B
-3 is engaged to set the second speed, the solenoid valve SL3 is turned on so that the signal pressure from the B-2 release valve 24 to the second pressure receiving surface A2 of the B-3 control valve 25 is increased. (PSLU) is applied. As a result, the control gain becomes a small gain, and the engagement pressure of the brake B-3 becomes low. On the contrary, when the solenoid valve SL3 is controlled to be off, the signal pressure (PSLU) to the second pressure receiving surface A2 of the B-3 control valve 25 is cut off, so that the control gain becomes a large gain and the brake B
The engagement pressure of -3 becomes high.

On the other hand, as shown in the operation table of FIG. 5, when the engine brake is applied at the first speed lower than the second speed, the first solenoid valve SL1 is turned on (◯) and the second solenoid valve SL1 is turned on. The solenoid valve SL2 is turned off (x), and the third solenoid valve SL3 is turned off (x). Therefore, from the standpoint of fail-safe, the combination of ON / OFF of the solenoid valves SL1, SL2, SL3 for setting the second speed is determined by the solenoid valves SL1, SL2, S.
It is preferable that all L3 are turned on (◯). However, if the third solenoid valve SL3 is turned on, as described above, the control gain of the engagement pressure of the brake B-3 becomes small, and the torque capacity of the brake B-3 may be insufficient. Therefore, the control device according to the present invention controls as described below.

FIG. 1 is a flow chart for explaining an example of the control. First, processing such as reading an input signal (step 1) is performed, and then the set running range (position) is shown in FIG. It is determined whether or not it is the "2" position shown (step 2). In addition, when targeting an automatic transmission that is provided with an L range for applying engine braking at the first speed, it may be also determined whether or not the L range is set in step 2. Good. In short, in this step 2, it is judged whether or not the range (position) in which the engine brake is applied at the first speed is set.

If a negative determination is made in step 2, the process returns without performing any control, and if an affirmative determination is made, on the contrary, it is determined whether or not the current gear is the second speed ( Step 3). If it is not the second speed, the process returns. On the other hand, when the vehicle is in the second speed, it is determined whether or not the vehicle speed V is equal to or higher than a predetermined reference value V1 as a determination that the condition is satisfied (step 4). That is, step 4 corresponds to the condition satisfaction determining means of the present invention.

If an affirmative decision is made in step 4, that is, if the vehicle speed V is equal to or higher than the reference vehicle speed V1, the first to third solenoids are used as the on / off combination of the solenoid valves for setting the second speed. Valve SL1, SL
A combination in which all of 2 and SL3 are turned on (◯) is selected (step 5). This combination is different from the combination of turning on / off the solenoid valves (first solenoid valve SL1 is on, second and third solenoid valves SL2, SL3 are off) to apply the engine brake at the first speed. This is a combination in which the two solenoid valves have different on / off states.

Therefore, even if, for example, a failure occurs in which the third solenoid valve SL3 is turned off in this state, this is a normal on / off pattern for setting the second speed as shown in FIG. There is no shifting. When a failure occurs in which the second solenoid valve SL2 is turned off, the on / off pattern is as shown in FIG.
As shown in (1), it is the first speed where the engine braking does not work, and even if a downshift occurs, unless the accelerator pedal (not shown) is depressed, the running state of the vehicle only becomes the coast state. Even if the accelerator pedal is depressed, the engine speed will increase.

As described above, when the third solenoid valve SL3 is turned on at the second speed, the third brake B
The control gain of the engagement hydraulic pressure of -3 becomes small, and the engagement pressure of the brake B-3, that is, the torque capacity decreases. However, when the vehicle speed V is high to some extent, the torque applied to the brake B-3 becomes small. The second speed can be maintained.

On the other hand, when the vehicle speed V is less than the reference vehicle speed V1 and a negative determination is made in step 4, the first and second combinations of the on / off states of the solenoid valves for setting the second speed are set. Solenoid valves SL1, SL2
Is turned on (◯) and the third solenoid valve SL3 is turned off (x) (step 6). This on / off pattern is different only in the on / off state of the second solenoid valve SL2 from the on / off pattern of the first speed in which engine braking is effective. Therefore, if the second solenoid valve SL2 is turned off due to a failure, a shift to the first speed in which engine braking is effective occurs.

However, when this on / off pattern is selected, the vehicle speed V is a low vehicle speed.
Even if a downshift occurs, the shock is small and there is no particular problem. Further, since the third solenoid valve SL3 is off, the control gain (pressure adjustment level) of the engagement pressure of the third brake B-3 is increased, and a sufficiently high engagement pressure, that is, torque capacity can be secured.

Therefore, the above steps 5 and 6 correspond to the pattern setting means of the present invention.

The on / off patterns for setting the second speed are the first to third solenoid valves SL.
The pattern in which all 1, SL2, SL3 are turned on is selected when the condition for avoiding the downshift to the first speed where engine braking is effective due to a failure is established. Therefore, the condition is that the output shaft speed N0 of the automatic transmission 10 is a predetermined reference speed N in addition to the vehicle speed V being equal to or higher than the reference vehicle speed V1 as described above.
The fact that it is O1 or more (step 4-1) may be adopted. Alternatively, both the vehicle speed V and the output shaft speed N0 may be used as conditions, and other conditions may be added or replaced.

If the vehicle speed V and the output shaft speed N0 are set as conditions, in order to avoid hunting, step 5
It is preferable to set a hysteresis between the condition for executing the control of 1) and the condition for executing step 6.

In the above-described specific example, the ON / OFF pattern of the solenoid valve for setting the second speed has been described as an example. However, the present invention is not limited to the above example, and other patterns are possible. It can also be applied when selecting the on / off pattern of the solenoid valve for setting the shift speed. The automatic transmission targeted by the present invention is not limited to the one provided with the gear train and the hydraulic circuit described above, and can be appropriately applied to the control device targeted for various automatic transmissions.

[0048]

As described above, according to the present invention,
When a preset condition such as the vehicle speed or the output shaft rotation speed being equal to or greater than a preset reference value is satisfied, the engine braking works as a combination of on / off of the solenoid valve for setting the predetermined shift speed. Automatically select a combination in which at least two solenoid valves have different on / off states compared to the on / off combination for low-speed gears.
Since manner to adopt, when setting the gear stage,
Even if any one of the solenoid valves fails, it is possible to avoid shifting to a low speed gear position where engine braking works. If the condition is not satisfied, the shift speed is changed depending on the combination of the on / off states of one solenoid valve that is different from the on / off combination of the solenoid valves that sets the shift speed on the low speed side where the engine brake works. The gears will be set, but by adopting the conditions that take into consideration the obstacles when a shift to the low-speed gear position where the engine brake works, the special discomfort due to the failure of the solenoid valve is avoided. can do.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining a control example by a control device according to the present invention.

FIG. 2 is a circuit diagram showing a part of a hydraulic circuit in the automatic transmission targeted by the present invention.

FIG. 3 is a schematic view showing the B-3 control valve.

FIG. 4 is a skeleton diagram of a gear transmission of the automatic transmission.

FIG. 5 is a chart showing an operating state of a friction engagement element for setting each shift speed in the automatic transmission.

FIG. 6 is a block diagram showing an overall control system thereof.

FIG. 7 is a time chart at the time of 1 → 2 shift by the automatic transmission.

FIG. 8 is a time chart at the time of 2 → 1 shift by the automatic transmission.

FIG. 9 is a time chart at the time of 2 → 3 shift by the automatic transmission.

[Explanation of symbols]

10 automatic transmission SL1, SL2, SL3 solenoid valve

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP 62-177342 (JP, A) JP 63-101548 (JP, A) JP 8-233093 (JP, A) JP 1- 288654 (JP, A) JP-A-8-233047 (JP, A) JP-A-63-172051 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-63 / 48

Claims (3)

(57) [Claims] 1. A plurality of shift speeds are set according to a combination of ON / OFF of a plurality of solenoid valves, and a combination of ON / OFF of solenoid valves for setting one of the shift speeds is set to a speed lower than the shift speed. The on / off state of at least two solenoid valves is different from the on / off state of the solenoid valves for effecting engine braking at the shift speed, and the on / off state of one solenoid valve is different In an automatic transmission control device capable of selecting two combinations of a combination, a condition satisfaction determining means for determining whether a predetermined condition is satisfied, and a condition satisfaction determining means for determining whether the condition is satisfied. If it is determined, the solenoid valve on / off combination for setting the shift speed is applied to the shift speed lower than the shift speed. The condition satisfaction determining means is such that at least two solenoid valves have different on / off states with respect to the on / off combinations of the solenoid valves for effecting the brake on, and the condition is not satisfied. When it is determined by the above, the on / off combination of the solenoid valve for setting the shift speed is changed to the on / off combination of the solenoid valve for applying the engine brake at the shift speed lower than the shift speed. control apparatus for an automatic transmission, characterized by comprising a pattern setting unit that automatically switches to cause union different states of one solenoid valve on and off for. 2. The condition is that the vehicle speed is a predetermined reference vehicle speed.
And the output shaft speed of the automatic transmission
At least one of the specified standard speeds or more
The automatic shift according to claim 1, wherein the automatic shift is one.
Machine control device. 3. The reference vehicle speed for determining whether the condition is satisfied
Or the standard speed and the above conditions are not met
Between the reference vehicle speed and the reference speed
3. Sterilization is set.
A control device for an automatic transmission according to.