JP2003156143A - Control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize an in-neutral control by detecting an abnormality without varying an output oil pressure of a hydraulic servo device every at a constant time. SOLUTION: In the in-neutral control, the clutch engaged when a traveling range is selected is engaged/disengaged by an output oil pressure of the hydraulic servo device and the output oil pressure of the hydraulic servo device is maintained to an in-neutral oil pressure in which the clutch slightly transmits a torque when the stopping state is detected in the state that the traveling range is selected. A calorific power per constant time of the clutch is determined based on the revolution numbers at the input side and the output side of the fluid transmission device and the abnormality is detected based on the calorific power of the clutch and an abnormality signal is outputted at the time of abnormality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission that performs a neutral control for releasing a clutch that is rotationally connected to a fluid transmission when the vehicle is stopped in a driving range.

[0002]

2. Description of the Related Art In an automatic transmission such as an automobile, when a vehicle is in a stopped state with a running range selected,
In order to improve fuel efficiency and prevent vibration of the vehicle, so-called neutral control is performed to release a clutch to which output rotation of a hydraulic power transmission device that transmits engine rotation to a transmission device is released. Conventionally, in order to perform neutral control, when it is detected that the vehicle is stopped, the hydraulic servo device that engages and disengages the clutch is controlled to output the output hydraulic pressure immediately before the clutch shifts from the engaged state to the slip state. Release control is performed to gradually reduce until the speed ratio Ni / Ne between the output side rotational speed Ni and the input side rotational speed Ne of the torque converter arranged between the engine and the clutch reaches a set value After that, the differential rotation speed dN between the input side rotation speed Ne and the output side rotation speed Ni is calculated at regular intervals.If the differential rotation speed dN does not change, the output hydraulic pressure of the hydraulic servo device is increased by a unit hydraulic pressure amount, and the differential rotation speed is increased. Japanese Patent No. 2804229 discloses a control device for an automatic transmission that reduces the output hydraulic pressure of a hydraulic servo device by a unit hydraulic pressure when dN changes and performs in-neutral control.

[0003]

In the above-mentioned conventional device,
If the differential rotation speed dN does not change even if the output hydraulic pressure of the hydraulic servo device is increased by a unit number of hydraulic pressures a predetermined number of times or more, an abnormal signal is output as an abnormality in in-neutral control, but the clutch slightly transmits torque. Even when the output hydraulic pressure of the hydraulic servo device is maintained at the in-neutral hydraulic pressure, there is a problem that the output hydraulic pressure of the hydraulic servo device must be changed at regular intervals in order to detect an abnormality.

[0004]

In order to solve the above-mentioned problems, a structural feature of the invention according to claim 1 is that a fluid transmission for transmitting the rotation of an engine to a transmission and a traveling range are selected. A clutch that is sometimes engaged, and a hydraulic servo device that supplies and discharges output hydraulic pressure to engage and disengage the clutch,
An input side rotation speed detection device for detecting an input side rotation speed of the fluid transmission device, an output side rotation speed detection device for detecting an output side rotation speed of the fluid transmission device, and a vehicle stop state detection means for detecting a vehicle stop state. And an automatic shift that performs in-neutral control to maintain the output hydraulic pressure of the hydraulic servo device at the in-neutral hydraulic pressure at which the clutch slightly transmits torque when the vehicle stop state is detected with the travel range selected. The control device of the machine is provided with means for obtaining the heat generation amount of the clutch, detecting an abnormality based on the heat generation amount of the clutch, and outputting an abnormality signal when the abnormality occurs.

According to a second aspect of the present invention, in the control device for an automatic transmission according to the first aspect, the heat generation amount of the clutch is determined by the rotational speeds of the input side and the output side of the fluid transmission. Based on this, the heat generation amount per constant time is obtained.

According to a third aspect of the present invention, there is provided a control device for an automatic transmission according to the first or second aspect.
Changing the in-neutral hydraulic pressure according to the amount of heat generated by the clutch.

According to a fourth aspect of the present invention, there is provided a control device for an automatic transmission according to the third aspect, wherein the in-neutral hydraulic pressure is reduced when the heat generation amount of the clutch is larger than a threshold value, and is small. Controlling the hydraulic servo device to increase the pressure.

According to a fifth aspect of the present invention, in the control device for an automatic transmission according to any one of the first to fourth aspects, the hydraulic servo device outputs at the end of the in-neutral control. The in-neutral hydraulic pressure is stored as a learning value, and when the vehicle stop state is detected next time when the travel range is selected, the hydraulic servo device outputs the learning value as an initial value of the in-neutral hydraulic pressure.

According to a sixth aspect of the present invention, there is provided the automatic transmission control device according to any one of the third to fifth aspects, wherein the abnormality detecting means changes the in-oil pressure to a predetermined value or more. That is to detect that the abnormality has occurred and output an abnormal signal.

According to a seventh aspect of the present invention, there is provided the automatic transmission control device according to any one of the second to fifth aspects, wherein the abnormality detecting means has a predetermined amount of heat generation per unit time. It is to output an abnormal signal by detecting that the heat generation amount is exceeded.

[0011]

In the invention according to claim 1 configured as described above, the clutch engaged when the travel range is selected is disengaged by the output hydraulic pressure of the hydraulic servo device so that the travel range is When the vehicle stop state is detected in the selected state, in the in-neutral control for maintaining the output hydraulic pressure of the hydraulic servo device at the in-neutral hydraulic pressure at which the clutch slightly transmits torque, the heat generation amount of the clutch is determined, Since an abnormality is detected based on the amount of heat generated by the clutch and an abnormality signal is output when an abnormality occurs,
It is not necessary to change the output hydraulic pressure of the hydraulic servo device at regular intervals in order to detect an abnormality, and stable in-neutral control can be performed.

In the invention according to claim 2 configured as described above, the heat generation amount per constant time of the clutch is determined based on the input side and output side rotational speeds of the fluid transmission, and the clutch is operated for a constant time. Since the in-neutral hydraulic pressure is changed according to the amount of heat generated per hit, stable so-called integral control is possible, and the effect of the invention according to claim 1 can be obtained.

In the invention according to claim 3 configured as described above, since the in-neutral hydraulic pressure is changed according to the amount of heat generated by the clutch, in addition to the effect of the invention according to claim 1, the input side is provided. Even if the rotation speed Ne changes, the hydraulic servo device does not respond excessively and stable in-neutral control can be performed.

In the invention according to claim 4 configured as described above, the hydraulic servo device is controlled so as to reduce the in-neutral hydraulic pressure when the heat generation amount of the clutch is larger than the threshold value, and increase the pressure when it is small. In addition to the effect of the invention described in 1, it is possible to perform stable in-neutral control with a simple configuration.

In the invention according to claim 5 configured as described above, the in-neutral oil pressure output by the hydraulic servo device at the end of the in-neutral control is stored as a learning value, and the traveling range is selected next time. Since the hydraulic servo device outputs the learning value as the initial value of the in-neutral hydraulic pressure when the vehicle stop state is detected in the state, the optimum value stored as the learning value is added to the effect of the invention according to claim 1. In-neutral control can be performed hydraulically.

In the invention according to claim 6 configured as described above, the abnormality signal is output by detecting that the in-eutral oil pressure has been changed to a predetermined value or more.
In addition to the effect of the invention described in claim 1, an abnormal signal is not output in response to an excess.

In the invention according to claim 7 configured as described above, the abnormal signal is output by detecting that the heat generation amount per constant time is equal to or more than the predetermined heat generation amount.
In addition to the effect of the invention described in (1), the abnormal signal can be output with a simple configuration.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a skeleton diagram showing an example of an automatic transmission 10 controlled by an automatic transmission control device according to the present invention. The automatic transmission 10 is a fluid transmission device in which an engine (not shown) is connected to an input side. Torque converter 11
And forward 6 connected to the output side of the torque converter 11
It is composed of a speed change mechanism 12 for first speed and reverse speed. The torque converter 11 includes a pump impeller 13, a turbine runner 14, a stator 15, a stator 15 and a transmission mechanism 12.
The case 16 is provided with a one-way clutch 17 that allows rotation in only one direction, and a stator shaft 18 that fixes the inner race of the one-way clutch to the case 16. 19 is a pump impeller 13 and a turbine runner 1
It is a lock-up clutch that directly connects with 4.

The transmission planetary gear G, which is the main part of the transmission mechanism 12, is of a double pinion type and directly meshes with the large diameter and small diameter sun gears S2, S3 and the large diameter sun gear S2 and also meshes with the small diameter sun gear S3 via the pinion P3. Long Pinion P2, Long Pinion P2 and Pinion P
3 and a ring gear R2 (R3) that meshes with the long pinion P2. The large-diameter sun gear S2 is connected to the first brake B-1, the carrier C2 (C3) is connected to the input shaft 20 via the second clutch C-2, and the one-way clutch F-1 supported by the case 16 is connected. And the brake B-2 are connected in parallel.

Reduction planetary gear G1 of the transmission mechanism 12
Is a single pinion type, a ring gear R1 as an input element is connected to the input shaft 20, and a carrier C1 as an output element has a small diameter sun gear S3 via a first clutch C-1.
And a large-diameter sun gear S2 via a third clutch C-3, and the sun gear S1 is fixed to the case 16 to receive a reaction force.

The relationship between the engagement and disengagement of each clutch, brake and one-way clutch of the automatic transmission 10 and each gear is shown in the engagement table of FIG. In the engagement table, ◯ indicates engagement, no mark indicates release, and Δ indicates engagement only during engine braking. FIG. 3 is a velocity diagram showing the relationship between the shift speed achieved by engagement of each clutch, brake and one-way clutch, and the rotational speed ratio of each element of the planetary gears G, G1 at that time.

As is apparent from FIGS. 2 and 3, the first speed (1
st) is the engagement of the clutch C-1 and the one-way clutch F-1.
It is achieved by automatic engagement of. The rotation of the carrier C1 in which the rotation of the input shaft 20 is reduced by the reduction planetary gear G1 is input to the small-diameter sun gear S3 of the transmission planetary gear G by the clutch C-1, and the reverse rotation is blocked by the one-way clutch F-1 (C3). Receives a reaction force, the ring gear R2 (R3) is decelerated and rotated at the maximum reduction ratio, and is output to the output shaft 21.

The second speed (2nd) is achieved by the engagement of the clutch C-1 and the brake B-1. The carrier C1 in which the rotation of the input shaft 20 is decelerated by the deceleration planetary gear G1.
Is input to the small-diameter sun gear S3 of the transmission planetary gear G via the clutch C-1, the large-diameter sun gear S2 whose rotation is blocked by the engagement of the brake B-1 receives a reaction force, and the ring gear R2 (R3) Output shaft 2 after being decelerated to 2nd speed
Output to 1. The speed reduction ratio at this time is smaller than that in the first speed (1st) as shown in FIG.

The third speed (3rd) is achieved by the engagement of the clutches C-1 and C-3. The carrier C in which the rotation of the input shaft 20 is decelerated by the deceleration planetary gear G1.
1 rotation is due to the small diameter sun gear S3 by the clutches C-1 and C-3
Is simultaneously input to the large-diameter sun gear S2 to directly connect the transmission planetary gear G, and the ring gear R2 (R3) is rotated at the same rotation speed as the carrier C1 and is output to the output shaft 21.

The fourth speed (4th) is achieved by the engagement of the clutch C-1 and the clutch C-2. The rotation of the input shaft 20 is directly input to the carrier C2 (C3) of the speed change planetary gear G by the clutch C-2, and the rotation of the carrier C1 reduced by the speed reduction planetary gear G1 is changed by the clutch C-1 to the speed change planetary gear. Input to the sun gear S3 of G, and the ring gear R2 (R3) is input to the input shaft 2
The speed is reduced to an intermediate speed between 0 and the carrier C1 and output to the output shaft 21.

The fifth speed (5th) is achieved by the engagement of the clutch C-2 and the clutch C-3. The rotation of the input shaft 20 is directly input to the carrier C2 (C3) of the transmission planetary gear G by the clutch C-2, and the rotation of the input shaft 20 is reduced by the reduction planetary gear G1. The rotation of the carrier C1 is the clutch C- of the transmission planetary gear G. It is input to the sun gear S2 by 3 and the ring gear R2 (R3) is rotated to the fifth speed and output to the output shaft 21.

The sixth speed (6th) is achieved by engagement of the clutch C-2 and the brake B-1. The rotation of the input shaft 20 is directly input to the carrier C2 (C3) of the transmission planetary gear G by the clutch C-2, and the sun gear S2 whose rotation is blocked by the engagement of the brake B-1 receives a reaction force, and the ring gear R2 (R3 ) Is rotated to the 6th speed and the output shaft 21
Output to.

Reverse (R) is clutch C-3 and brake B-2.
Is achieved by engagement with. The rotation of the input shaft 20 is reduced by the deceleration planetary G1 and the rotation of the carrier C1 is transmitted through the clutch C-3 to the sun gear S2 of the transmission planetary gear G.
Is input to the carrier C2 (C3), which is prevented from rotating by the engagement of the brake B-2, receives a reaction force, and the ring gear R2
(R3) is reversed and output to the output shaft 21.

In the automatic transmission 10 described above, the clutch
A torque converter 1 which is a fluid transmission device in which C-1 is engaged and coupled to an engine when a travel range is selected.
1 is a clutch for transmitting the output of 1 to the drive wheels via the output shaft 21, and when the vehicle stops and the rotation of the output shaft 21 is blocked in the state where the traveling range is selected, the clutch is released to perform the neutral control. It is supposed to be done. When the driving range is selected, the vehicle is stopped by the braking force of the brake and the first speed is established. When the neutral control is performed and the clutch C-1 is released, the first speed to the second speed are selected. Therefore, when the brake is released at the time of starting, the brake B1 prevents the output shaft 21 from rotating in the reverse direction even if a backward force is applied to the vehicle on an uphill slope, so the vehicle does not move backward and the clutch C-1 The vehicle starts smoothly when the driving force is transmitted by engaging with the vehicle. When engine braking is required, the brake B-2 is engaged and the carrier C2 (C
3) is prevented from rotating normally, and the rotation from the output shaft 21 is transmitted to the engine via the sun gear S3, the clutch C-1, the deceleration planetary G1, and the torque converter 11, and the engine brake is applied.

Next, the hydraulic servo device 26 for outputting the hydraulic pressure supplied to and discharged from the hydraulic drive unit of the clutch C-1 will be described with reference to FIG. Reference numeral 25 denotes a manual valve in which the driver manually operates the shift lever to switch between the neutral N, the traveling range D, and the reverse range R, and the line pressure from the oil pump is supplied to the port PL. The amplification valve 27 of the hydraulic servo device 26 that outputs the hydraulic pressure supplied to the hydraulic drive unit of the clutch C-1 is connected to the port D that communicates with the port PL when the manual valve 25 is shifted to the travel range.
Input port 28 and line pressure port 30 of switching valve 29
Are connected to each other. Reference numeral 31 is a solenoid modulator valve to which the line pressure from the oil pump is supplied via a pressure reducing valve.
6 to the input port 33 of the linear solenoid pressure regulating valve 32 and the port 34 of the switching valve 29. The linear solenoid pressure regulating valve 32 operates according to a control current, which is a control signal supplied from a control device described later, to move the linear solenoid 35 until the valve body 36 is balanced with the spring force of the compression spring 37, and the input port The control hydraulic pressure flowing from 33 is controlled to a predetermined pressure, and a control hydraulic pressure that decreases as the control current from the control device increases is generated at the output port 38. The output port 38 of the linear solenoid pressure regulating valve 32 is the amplification valve 2
7 is connected to the control port 39 and the switching valve 29
Is connected to the switching port 40. In the amplification valve 27, the compression spring 4 in which the axial force by the control hydraulic pressure of the linear solenoid pressure regulating valve 32, which is supplied to the control port 39 from the valve body 40 and acts on the large-diameter end surface of the valve body 40, acts on the small-diameter end surface of the valve body 40.
The output hydraulic pressure Pc is output by the control hydraulic pressure of the linear solenoid pressure regulating valve 32, which is moved to a position where the spring force of 1 and the axial force by the feedback hydraulic pressure are balanced and the line pressure supplied to the input port 28 decreases as the control current increases. , From the output port 42 to the input port 43 of the switching valve 29. The switching valve 29 connects the input port 43 to the output port 44 when the valve body 45 is shifted to the right half position in the drawing.
When the output hydraulic pressure Pc from the amplification valve 27 is supplied to the hydraulic drive unit of the clutch C-1 and the valve body 45 is shifted to the left half position in the drawing, the line pressure port 30 communicates with the output port 44 and the manual valve 25 The line pressure from port D is supplied to the hydraulic drive unit of the clutch C-1, and the clutch C-1 is maintained in the engaged state by the line pressure.

A control device for the automatic transmission will be described with reference to the block diagram shown in FIG. Control device 50 with built-in CPU
Is a torque converter 11 to which the rotation of the engine is transmitted.
Input side rotation speed sensor 51 for detecting the input side rotation speed Ne of
An output side rotation speed sensor 52 which detects an output side rotation speed Ni of the torque converter 11 which is an input side of the clutch C-1, and a throttle opening degree sensor 5 which detects an accelerator depression amount Ss.
3, the foot brake sensor 54 that sends out the brake depression signal Bs, the vehicle speed sensor 55 that detects the rotation speed Nv of the output shaft 20, and the manual valve 25 are the travel range D.
The respective detection signals are input from the range position sensor 56 that outputs the signal Dr indicating whether or not the shift has been performed, and the brake hydraulic pressure sensor 57 that detects the brake hydraulic pressure Bp, and the control program is executed based on these detection signals to perform control. A control current, which is a signal, is output to the linear solenoid pressure regulating valve 32 of the hydraulic servo device 26, and the abnormality lamp 58 is turned on when there is an abnormality.

Next, the operation of the control device for the automatic transmission according to the present invention will be described with reference to the flow charts of the neutral control program shown in FIGS. When the manual valve 25 of the automatic transmission 10 is shifted to the travel range and the brake is applied during traveling to stop the vehicle, the vehicle control device 50 establishes the first speed and the input side rotation sensor 51,
Each detection signal is fetched from the output side rotation sensor 52, the throttle opening sensor 53, the foot brake sensor 54, the vehicle speed sensor 55, the range position sensor 56, and the brake oil pressure sensor 57 (step 61), and the start condition of the release standby control is satisfied. It is checked whether or not (step 62). The start condition of the release standby control is the torque converter 11
Output side rotation speed Ni of the vehicle has decreased to the standby control rotation speed Nw, that is, the vehicle speed has decreased to the speed immediately before the stop, the brake is depressed, and the foot brake sensor 5
The signal Bs from 4 is ON, and the signal Ss from the throttle opening sensor 53 detects that the throttle opening is substantially zero, that is, the idle state. It is to be established.

When the start condition of the release standby control is satisfied, the control device 50, as shown in FIG. 8 (a), causes the hydraulic pressure supplied to the hydraulic drive unit of the clutch C-1 to be in the engagement state of the clutch C-1. The engagement hydraulic pressure Pl (line pressure) maintained at is decreased to the standby pressure Pw which is slightly higher than the hydraulic pressure immediately before the clutch C-1 starts slipping (step 63). The standby pressure Pw is the so-called stall torque Ts generated in the torque converter 11 when the input side rotation speed of the torque converter 11 is Nei in the engine idle state and the output side rotation speed Ni is zero in the stopped state, It is set to be slightly higher than the output hydraulic pressure Pc of the hydraulic servo device 26 when the clutch C-1 starts slipping. The control device 50 supplies the control current corresponding to the standby pressure Pw to the linear solenoid 35 of the hydraulic servo device 50, and the control hydraulic pressure according to the control current is generated at the output port 38 of the linear solenoid pressure regulating valve 32, so that the amplification valve 27 Outputs the standby pressure Pw corresponding to the control oil pressure to the switching valve 29. In the switching valve 29, since the control hydraulic pressure supplied from the pressure regulating valve 32 to the switching port 40 decreases in accordance with the control current, the sum of the control hydraulic pressure and the spring force of the compression spring 46 is supplied from the solenoid modulator valve 31 to the port 34. Since the pressure becomes smaller than the predetermined pressure and the valve element 45 is shifted to the right half position in the drawing,
The standby pressure Pw is supplied to the clutch C-1 as the output hydraulic pressure Pc from the hydraulic servo device 26.

Since the idle speed of the engine changes depending on the operating condition, the input side speed Nei of the torque converter 11 and thus the stall torque also change in the idle state of the engine, and the standby pressure changes according to the stall torque.
You need to change Pw. The stall torque Ts is 0 when the speed ratio r is 0 based on the relationship graph shown in FIG. 9 of the speed ratio r which is the ratio of the output side rotation speed Ni and the input side rotation speed Ne and the transmission torque ratio t of the torque converter 11. The product of the stall torque ratio ts at this time, the stall torque capacity coefficient Cs, and the square of the input side rotation speed Ne at that time, Ts = ts × Cs × Ne ² . Then, the standby pressure Pw is Pw = Ts / X + Y + αw. Here, Ne is the input side rotational speed Nei in the idle state, and X is the product of the area of the piston of the hydraulic drive unit of the clutch C-1 and the product of the effective radius of the clutch plate, the number of plates, and the friction coefficient. , Y is a stroke pressure required to move the piston to a position where the clutch plate comes into contact and the clutch C-1 starts slipping, and αw is a margin value.

The output hydraulic pressure Pc of the hydraulic servo device 26 is the standby pressure.
When Pw is reached, the control device 50 determines whether or not the vehicle has stopped (step 64). When the vehicle is stopped, for example, the brake hydraulic pressure Bp detected by the brake hydraulic pressure sensor 57 is the brake hydraulic pressure Bp immediately before the vehicle starts to move.
signal Bs from the foot brake sensor 54 is on, and a signal from the throttle opening sensor 53.
It is determined by Ss that all three conditions that the throttle opening is substantially zero, that is, that the throttle is in the idle state are satisfied.

When it is determined that the vehicle is stopped, the flag is set.
FSTOP is set (step 65), and release control is started. The control device 50 controls the output hydraulic pressure Pc of the hydraulic servo device 26, as shown in FIG. 8A, to a release start hydraulic pressure Ps near the transition point at which the clutch C-1 shifts from the engaged state to the slip state, preferably, the release start hydraulic pressure Ps. In order to sharply reduce the release start hydraulic pressure Ps immediately before shifting to the slip state, a release start current Is that causes the hydraulic servo device 26 to generate the release start hydraulic pressure Ps is applied to the linear solenoid 35 of the linear solenoid valve 32 (step 66). When the vehicle stop state is detected, the output side rotation speed Ni of the torque converter 11 is 0, as shown in FIG. 8B, so that the clutch C-1 has the input side rotation speed Nei in the idle state. A certain stall torque Ts is applied. Therefore, the release start hydraulic pressure is expressed by the formula Ps = Ts / X + Y + as in the standby pressure Pw.
Calculated by αs. αs can be 0 or an extremely small positive or negative value, but is preferably an extremely small positive value to be the hydraulic pressure immediately before the clutch C-1 shifts from the engaged state to the slip state.

When the output hydraulic pressure Pc is reduced to the release start hydraulic pressure Ps, it is determined whether or not the neutral control is performed for the first time (step 67), and if it is the first time, the memory of the control device 50 is determined. The output hydraulic pressure Pc is gradually reduced toward the initial set value Pin.st registered as the data value in step 68a. The default setting Pin.st is the clutch
The output hydraulic pressure Pc of the hydraulic servo device 26 that causes C-1 to slightly transmit torque, for example, the output hydraulic pressure Pc immediately after the clutch C-1 has changed from the slip state to the drag state.
Is the value obtained from calculation, test, etc. Immediately after the completion of vehicle assembly, immediately after repairing the automatic transmission, and immediately after making a large adjustment at the time of vehicle inspection or the like, the output hydraulic pressure Pc is gradually reduced toward the initial set value Pin.st assuming that it is the first time. If it is not the first time, the learning value Pin.n stored in the learning value memory Pin.now storing the in-neutral oil pressure Pin written in the output memory Pc at the end of the previous in-neutral control.
The output hydraulic pressure Pc is gradually reduced toward ow (step 68).
b). It is determined whether or not the vehicle is stopped during the release control (step 69), the brake is released, the signal Bs from the foot brake sensor 54 is turned off, and the driver's intention to start, in other words, the starting operation is detected. If so, the process shifts to the apply control described later. Output hydraulic pressure Pc is the initial setting value
When it decreases to Pin.st or learning value Pin.now (Step 7
0), the control device 50 starts the in-neutral control shown in FIG. 7.

In the case of the first neutral control, when the in-neutral control is started, the initial set value Pi is set as described above.
n.st is in a state of being written in the output memory Pc indicating the output hydraulic pressure Pc of the hydraulic servo device 26, the control current Iin.st corresponding to the initial set value Pin.st is applied to the linear solenoid 35, and the hydraulic servo device 26 outputs the initial set value Pin.st as the initial value of the in-neutral oil pressure Pin. If it is not the first time, the learning value Pin.now is written in the output memory Pc at the start of the in-neutral control, and the control current Iin.now corresponding to the learning value Pin.now is applied to the linear solenoid 35. , The hydraulic servo device 26 is the learning value Pi
n.now is output as the initial value of the in-neutral oil pressure Pin.

When the in-neutral control is started, the parameters are initialized. In-Eutral Hydraulic Pi
In order to maintain n appropriately, when the in-neutral oil pressure Pin is increased / decreased by the unit oil pressure amount dP at every constant time J (for example, 1 second), if the unit oil pressure amount dP is increased, the coefficient value A is set to 1 When the pressure is reduced and the pressure is reduced, 1 is subtracted and the correction counter A is reset (step 71), and the heat generation amount dQ of the clutch C-1 at the minute time dJ (for example, 10 milliseconds) is added at every minute time dJ. The calorific value memory Q for storing the cumulative calorific value Q and the cumulative number C and the cumulative number counter C are reset (step 72).

The input side and output side rotation speeds Ne and Ni of the torque converter 11 are the input side and output side rotation speed sensors 51, 5 respectively.
2 is read (step 73), and the heat generation amount dQ of the clutch C-1 at the minute time dJ is obtained. At the second speed that is selected when the in-neutral control is being performed, the clutch C-2 is disengaged and the transmission torque of the torque converter 11 is not distributed, so the torque converter 1
The transmission torque Tc of 1 is all transmitted to the clutch C-1. Therefore, the heat generation amount dQ of the minute time dJ of the clutch C-1 is calculated by multiplying the transmission torque Tc of the torque converter by the output side rotation speed Ni,
It is calculated by dQ = Tc × Ni × dJ (step 74). The transmission torque Tc is calculated by multiplying the speed ratio r = Ni / Ne between the output side rotation speed Ni and the input side rotation speed Ne by the product of the torque ratio t and the capacity coefficient C obtained from the graph of FIG. It is obtained by multiplying the square of the number Ne by the formula Tc = t × C × Ne ² . The calorific value dQ of the clutch C-1 at the minute time dJ calculated in this way is sequentially added (steps 73 to 77), and the minute calorific value dQ is the number of times Ct = J until the calorific value Q per constant time J is reached. It is determined whether or not only / dJ has been added (step 77).

When the cumulative number counter C reaches Ct and the calorific value Q of the clutch C-1 per constant time J is obtained as shown in FIG. 10, the calorific value Q is a value obtained by adding the allowable width dQt to the threshold value Qt. It is determined whether or not it is larger (step 78). If it is larger, the unit oil pressure dP is subtracted from the output memory Pc, the control current Iin corresponding to the output oil pressure (Pc-dP) is applied to the linear solenoid 35, and the hydraulic servo is Device 26 is hydraulic (Pc-d
P) is output as the in-neutral hydraulic pressure Pin (step 79). Then, 1 is added to the correction number memory A (step 80). When the heat generation amount Q per unit time is smaller than the threshold value Qt minus the allowable width dQt, it is determined whether the heat generation amount Q is smaller than the threshold value Qt minus the allowable width dQt (step 81). At this time, the unit hydraulic pressure amount dP is added to the output memory Pc, the control current Iin corresponding to the output hydraulic pressure (Pc + dP) is applied to the linear solenoid 35, and the hydraulic servo device 26 outputs the hydraulic pressure (Pc + dP) as the in-neutral hydraulic pressure Pin. (Step 82). Then, 1 is subtracted from the correction number memory A (step 83). In the above case, in order to reduce the number of corrections of the in-neutral hydraulic pressure Pin, the allowable width dQt is added to or subtracted from the threshold value Qt and compared with the heat generation amount Q per unit time.
Qt may be compared with the calorific value Q.

It is judged whether or not the absolute value of the correction number memory A is larger than the predetermined number An (step 84), and when it becomes larger, an abnormality signal is output and an abnormality notification such as turning on the abnormality lamp 58 is made (step 85). , The neutral control is ended. The fact that the absolute value of the correction count memory A becomes larger than the predetermined count An means that the output hydraulic pressure Pc of the hydraulic servo device 26 is
A predetermined value (dP x An) obtained by multiplying the unit hydraulic pressure dP by a predetermined number of times An
Even if the pressure is reduced or increased, the heat generation amount Q per unit time does not fall within the allowable range from the threshold value. Even if the output hydraulic pressure Pc of the hydraulic servo device 26 is changed to a predetermined value or more, the clutch C-
If the calorific value Q of 1 does not improve, it is regarded as abnormal. Thus, steps 73 to 77 and steps 80 to 8
5, the calorific value Q per constant time J of the clutch C-1 is obtained based on the input side and output side rotational speeds Ne and Ni of the torque converter 11, and the abnormality is determined based on the calorific value Q of the clutch C-1. Means are provided for detecting and outputting an abnormal signal when an abnormality occurs.

When it is determined in step 81 that the heat generation amount Q per unit time is larger than the value obtained by subtracting the allowable width dQt from the threshold value Qt, and when the absolute value of the correction count memory A is smaller than the predetermined count An in step 84. If determined, it is determined whether or not the vehicle is in a stopped state (step 86), and when the driver's intention to start is detected, such as when the brake is released and the signal Bs from the foot brake sensor 54 is turned off, The controller 50 writes the current in-neutral oil pressure Pin written in the output memory Pc into the learning value memory Pin.now as the learning value Pin.now (step 87). Then, in order to start the gradual increase of the output hydraulic pressure Pc of the hydraulic servo device 26, the control current is slightly increased stepwise and then gradually increased to perform the apply control (step 88). When the output hydraulic pressure Pc of the hydraulic servo device 26 is increased to the standby pressure Pw and the apply control ends, the control device 50 causes the linear solenoid pressure regulating valve 3 to operate.
Since the supply of the control current to the second linear solenoid 35 is stopped, the valve body 36 is moved to the open position by the compression spring 37, and the control hydraulic pressure generated at the output port 38 becomes the predetermined pressure supplied from the solenoid modulator valve 31. The valve body 45 of the switching valve 29 is moved up and shifted to the left position in the drawing, the clutch C-1 is supplied with the line pressure from the manual valve 25 to be in the normal engagement state, and the neutral control is finished (step 89). .

As means for outputting an abnormal signal at the time of abnormality, at steps 73 to 77 of the program of FIG. 7, the clutch C-1 per constant time J is determined based on the input side and output side rotational speeds Ne and Ni of the torque converter 11. The heat generation amount Q of the clutch C-1 is determined, and it is determined whether or not the heat generation amount Q of the clutch C-1 is larger than the predetermined heat generation amount QL. If the heat generation amount Q is large as indicated by the alternate long and short dash line 90 in FIG. May be output.

[Brief description of drawings]

FIG. 1 is a skeleton diagram of an automatic transmission controlled by a control device for an automatic transmission according to the present invention.

FIG. 2 is an engagement table of clutches and brakes at each shift speed of the automatic transmission.

FIG. 3 is a speed diagram showing a rotation speed ratio of each element of the planetary gear at each speed stage of the automatic transmission.

FIG. 4 is a diagram showing a hydraulic servo device that engages and disengages a clutch C-1.

FIG. 5 is a block diagram showing a control device for an automatic transmission.

FIG. 6 is a flow chart of a neutral control program.

FIG. 7 is a flow chart of a neutral control program showing in-neutral control in detail.

FIG. 8 is a time chart of neutral control.

FIG. 9 is a diagram showing a speed ratio, a torque ratio, and a torque capacity coefficient.

FIG. 10 is a diagram showing a state in which minute heat generation amounts of the clutch C-1 in a minute time are accumulated to obtain a heat generation amount Q per constant time. 10 ... Automatic transmission, 11 ... Torque converter (fluid transmission device), 12 ... Transmission mechanism, 20 ... Input shaft, 21 ... Output shaft, 25 ... Manual valve, 26 ... ..Hydraulic servo devices, 27 ... amplification valves, 2
9 ... Switching valve, 32 ... Linear solenoid pressure regulating valve,
35 ... Linear solenoid, 50 ... Control device, 5
1 ... Input speed sensor, 52 ... Output speed sensor, 53 ... Throttle opening sensor, 54 ...
Foot brake sensor, 56 ... Range position sensor,
57 ... Brake oil pressure sensor, 58 ... Abnormality lamp, C-1 ... Clutch, Q ... Heat value, dQ ... Minute heat value, Qt ... Threshold value, dQt ... Allowable width , QL ... predetermined heat value, Pin ... in-neutral hydraulic pressure, dP ...
Unit hydraulic pressure, J ... fixed time, An ... predetermined number of times.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16H 59:44 F16H 59:44 63:12 63:12

Claims (7)

[Claims] 1. A hydraulic power transmission device for transmitting engine rotation to a transmission, a clutch engaged when a travel range is selected, and a hydraulic servo device for supplying / discharging output hydraulic pressure to engage / disengage the clutch. An input side rotation speed detection device for detecting the input side rotation speed of the fluid transmission, an output side rotation speed detection device for detecting the output side rotation speed of the fluid transmission, and a vehicle stop state detection for detecting a vehicle stop state. Means for performing in-neutral control for maintaining the output hydraulic pressure of the hydraulic servo device at the in-neutral hydraulic pressure at which the clutch slightly transmits torque when the vehicle stop state is detected with the travel range selected. The automatic transmission control device is provided with means for obtaining a heat generation amount of the clutch, detecting an abnormality based on the heat generation amount of the clutch, and outputting an abnormality signal when the abnormality occurs. A control device for an automatic transmission characterized by: 2. The automatic transmission according to claim 1, wherein the calorific value of the clutch is obtained as a calorific value per constant time based on the input side and output side rotational speeds of the fluid transmission. Control device. 3. The in-neutral hydraulic pressure is changed according to the amount of heat generated by the clutch.
Alternatively, the control device for the automatic transmission according to item 2. 4. The automatic transmission according to claim 3, wherein the hydraulic servo device is controlled so that the in-neutral hydraulic pressure is reduced when the heat generation amount of the clutch is larger than a threshold value, and is increased when the calorific value is smaller than a threshold value. Control device. 5. The in-neutral hydraulic pressure output from the hydraulic servo device at the end of the in-neutral control is stored as a learning value, and when the vehicle stop state is detected next time with the travel range selected, the hydraulic pressure The control device for the automatic transmission according to any one of claims 1 to 4, wherein the servo device outputs the learned value as an initial value of the in-neutral hydraulic pressure. 6. The automatic transmission according to claim 3, wherein the abnormality detecting means detects that the in-eutral oil pressure has been changed to a predetermined value or more and outputs an abnormality signal. Control device. 7. The abnormality detecting means outputs an abnormality signal by detecting that the amount of heat generated per unit time is equal to or greater than a predetermined amount of heat generated. Automatic transmission control device.