JP3787880B2 - Control device for automatic transmission for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is suitable for use in an automatic transmission mounted on a vehicle, particularly a continuously variable automatic transmission having a torque converter having a lock-up clutch and a belt-type continuously variable transmission (CVT). The present invention relates to a control device for detection means.
[0002]
[Prior art]
Conventionally, an automatic transmission, for example, a continuously variable automatic transmission, has been provided with each rotation sensor that detects an engine speed, an input speed (primary sheave speed), and a vehicle speed (secondary sheave speed). The gear ratio and the like are controlled based on the rotation speed.
[0003]
In general, a rotation speed sensor is a member to be detected that is formed by directly forming a concave-convex shape on a rotary member such as a primary or secondary sheave by cutting or by fixing a concave-convex member formed by pressing to the rotary member. An electromagnetic pickup (magnetic sensor) is arranged close to each other, and a change in dielectric current generated when the unevenness of the detected member passes through the electromagnetic pickup portion in a non-contact manner is measured by a control unit (microcomputer). Thus, the rotation speed (rotation angle) of the detected member is detected.
[0004]
[Problems to be solved by the invention]
Recently, there is a demand for detection of the number of rotations at low speed rotation, such as creep prevention control and reverse inhibition control. In particular, when the lock-up clutch is slip-controlled due to the improvement of fuel consumption and the torque ratio amplification restriction of the torque converter, a high measurement accuracy of the engine speed is required at the time of low-speed rotation.
[0005]
By the way, if the number of irregularities of the detected member is increased, the rotation speed sensor improves the measurement accuracy of the low-speed rotation speed, but at the time of high-speed rotation, the rotation speed calculation processing by the control unit increases, and other processing is hindered. There is a risk that it will come, and the improvement in accuracy during low-speed rotation by increasing the number of irregularities is restricted from the counter processing capacity in the control unit.
[0006]
Therefore, the present invention is a vehicle that solves the above-mentioned problems by detecting the engine speed with an input speed sensor during high speed rotation with a lockup clutch directly connected, and dedicated the engine speed sensor during low speed rotation. It is an object of the present invention to provide a control device for an automatic transmission for a vehicle.
[0007]
[Means for Solving the Problems]
  The present invention has been made in view of the above circumstances, and transmits torque from an engine to a transmission (2) via a torque converter (6) having a lock-up clutch (5). In the automatic transmission (1) for a vehicle, in which the torque shifted at is transmitted to the axle (60, 61),
  Input rotation speed detection means (62) for detecting the input rotation speed of the transmission,
  With higher resolution than the input rotational speed detection means (62)Engine speed detecting means (65) for detecting the engine speed;
  The lock-up clutch (5)Fully engagedEngagement stateExcluding thatLock-up detection means (100a) for detecting whether or not disengaged;
  When the lock-up detection means detects the non-engagement state of the lock-up clutch, the signal from the engine speed detection means (65) is input as the engine speed, and the lock-up clutch A switching control means (100) for switching so as to input the signal from the input rotational speed detection means (62) as an engine rotational speed when the engagement state is detected;
  It is characterized by providing.
[0008]
  Preferably, the lock-up clutch is slip controlled.In the slip control, the switching control means (100) is configured to input a signal from the engine speed detection means (65) as the engine speed.
[0009]
The transmission is preferably a belt type continuously variable transmission (1).
[0010]
[Action]
Based on the above configuration, signals from the sensors such as the accelerator sensor (64) and the output rotation speed sensor (63) are input to the control unit (100), and by processing these signals, a lockup solenoid A lock-up OFF signal or a lock-up ON signal is output to the valve (97), and the lock-up clutch (5) is operated to an engaged state or a non-engaged state. When the lockup detection means (100a) detects the non-engagement state of the lockup clutch, the switching control means (100b) directly inputs the signal from the engine speed sensor (65) as the engine speed. When the engagement state of the lockup clutch is detected, the switching control means inputs the signal from the input rotational speed sensor (62) as the engine rotational speed.
[0011]
In addition, although the code | symbol in the said parenthesis is for contrast with drawing, it does not limit the structure of this invention at all.
[0012]
【The invention's effect】
According to the first aspect of the present invention, in the high speed running state in which the lockup clutch is engaged, the signal from the input speed sensor is input as the engine speed, so the engine speed sensor is operated at high speed. It is possible to use what can be detected with high resolution without being limited by the counter processing capacity in the control unit at the time, and increase the processing capacity of the control unit in the detection accuracy of the engine speed in the low speed running state It can be improved without increasing the cost.
[0013]
According to the second aspect of the present invention, the slip control of the lock-up clutch requires the detection of the engine speed with high accuracy during low-speed traveling. For example, the uneven portion of the rotated member detected by the electromagnetic pickup It is possible to easily cope with this by improving the detection accuracy of the engine speed by increasing the number of
[0014]
According to the third aspect of the present invention, the belt-type continuously variable transmission has a limited input torque due to the belt capacity and the like, but the torque ratio amplification of the torque converter at the start is controlled by the slip control of the lockup clutch. Regulation within the range of torque capacity can be easily performed by detecting the engine speed with high accuracy during low-speed traveling as described above.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing a continuously variable automatic transmission 1 for a vehicle to which the present invention can be applied. The continuously variable automatic transmission includes a belt type continuously variable transmission (CVT) 2, a forward / reverse / mode switching device 3. A torque converter 6 with a built-in lock-up clutch 5, a counter shaft 7 and a differential device 9 are provided, and these devices are covered with a divided case.
[0016]
The torque converter 6 includes a pump impeller 11 connected to the engine output shaft 10 via a front cover 17, a turbine runner 13 connected to the input shaft 12, and a stator 16 supported via a one-way clutch 15. In addition, a lock-up clutch 5 is interposed between the input shaft 12 and the front cover 17. In the figure, 20 is a damper spring interposed between the lock-up clutch plate and the input shaft, and 21 is an oil pump connected to the pump impeller 11 and driven.
[0017]
The CVT (belt type continuously variable transmission) 2 is fixed to a primary pulley 26 including a fixed sheave 23 fixed to a primary shaft 22 and a movable sheave 25 supported only slidably on the shaft, and a secondary shaft 27. A secondary sheave 31 comprising a fixed sheave 29 and a movable sheave 30 that is slidably supported on the shaft, and a metal belt 32 wound around these pulleys.
[0018]
Further, a hydraulic actuator 33 composed of a double piston is disposed on the back surface of the primary side movable sheave 25, and a hydraulic actuator 35 composed of a single piston is disposed on the back surface of the secondary side movable sheave 30. The primary hydraulic actuator 33 includes a cylinder member 36 and a reaction force support member 37 fixed to the primary shaft 22, a cylindrical member 39 and a piston member 40 fixed to the movable sheave 25, and the cylindrical member 39, the first hydraulic chamber 41 is configured by the reaction force support member 37 and the back surface of the movable sheave 25, and the second hydraulic chamber 42 is configured by the cylinder member 36 and the piston member 40. The first hydraulic chamber 41 and the second hydraulic chamber 42 communicate with each other through a communication hole 37a, and generate an axial force that is approximately double that of the secondary hydraulic actuator 35 with the same hydraulic pressure. To do. On the other hand, the secondary side hydraulic actuator 35 has a reaction force support member 43 fixed to the secondary shaft 27 and a cylindrical member 45 fixed to the back surface of the movable sheave 30. A hydraulic chamber 46 is configured, and a preload spring 47 is contracted between the movable sheave 30 and the reaction force support member 43.
[0019]
The forward / reverse / mode switching device 3 includes a double pinion planetary gear 50 for switching forward and backward, a reverse brake B₁ First (D range) clutch C₁ Second (L range) clutch C₂ And the one-way clutch F between the input shaft 12 and the fixed sheave 23 of the primary pulley 26.₂ And the first clutch C₁ And the one-way clutch F is arrange | positioned in parallel. The planetary gear 50 has a sun gear S connected to the input shaft 12, and the first and second pinions P₁ , P₂ Is supported by the primary fixed sheave 23, and the ring gear R is connected to the reverse brake B.₁ It is connected to.
[0020]
A large gear 51 and a small gear 52 are fixed to the counter shaft 7, the large gear 51 is engaged with a gear 53 fixed to the secondary shaft 27, and the small gear 52 is engaged with a gear 55 of the differential device 9. ing. In the differential device 9, the rotation of the differential gear 56 supported by the differential case 56 having the gear 55 is transmitted to the left and right axles 60 and 61 via the left and right side gears 57 and 59.
[0021]
Further, a plurality of, for example, 20 uneven portions 23a are formed at equal intervals on the outer peripheral portion of the primary side fixed sheave 23 by gear cutting, and are fixed to a case (not shown) so as to face the uneven portions. Thus, an electromagnetic pickup 62 is arranged. Similarly, a plurality of, for example, twelve uneven portions 29a are formed at equal intervals on the outer peripheral portion of the secondary-side fixed sheave 29 by gear cutting, and are fixed to the case so as to face the uneven portions, and the electromagnetic pickup 63 Is arranged. Each of the electromagnetic pickups 62 and 63 has a detection surface disposed close to the uneven portion, and constitutes a primary (input) rotation speed sensor and a secondary (output) rotation speed (ie, vehicle speed) sensor for detecting the uneven portion. is doing. On the other hand, FIG. 1 shows an electromagnetic pickup 65 disposed close to the front cover 17. For example, the electromagnetic pickup 65 is coaxial with a signal rotor or a crank pulley provided in the distributor. It is provided in the vicinity of the signal display plate provided in a shape, and constitutes an engine speed sensor that detects a large number, for example, 106 irregularities formed on the rotor or plate.
[0022]
Next, the hydraulic circuit of the continuously variable transmission will be described with reference to FIG. In the figure, 21 is the oil pump, 70 is an oil pump control valve, and 71 is a solenoid valve for the control valve. Reference numeral 72 is a primary regulator valve, 73 is a secondary regulator valve, 75 is a line pressure control linear solenoid valve, and 76 is a solenoid valve modulator valve.
[0023]
77 is a manual valve, and the hydraulic pressure of the line pressure port 1 is switched to the port 2 or 3 as shown in the table by manual operation. 79 is a modulator valve, 80 is a C2 control valve, 81 is a duty control solenoid valve, and C2 and C1 are the clutch C₁ , C₂ Hydraulic servo, B1 is the brake B₁ The hydraulic servos 90 and 91 are B1 and C1 accumulators, respectively. 92 is a ratio control valve, 93 is a linear solenoid valve for CVT control (ratio control), and 33 and 35 are the primary and secondary hydraulic actuators.
[0024]
Reference numeral 95 is a lockup control valve, 96 is a lockup relay valve, and 97 is a linear solenoid valve for lockup control. Reference numeral 6 denotes a torque converter having the lock-up clutch 5. Reference numeral 6a denotes an oil passage communicating with the lock-up off-side oil chamber 5a, and reference numeral 6b denotes an oil passage communicating with the lock-up on-side oil chamber 5b. In the figure, x is a drain port.
[0025]
As shown in FIG. 3, the engine rotational speed sensor 65, the input rotational speed sensor 62, the output rotational speed sensor 63, the output rotational speed sensor 63, the sensor 64 for detecting the accelerator depression amount, that is, the throttle opening, and the position position of the manual valve. A signal from the sensor 66 for detecting the signal is sent to a control unit (ECU) 100 comprising an in-vehicle computer. Various calculations are performed by the ECU 100, and the oil pump solenoid valve 71, the line pressure linear solenoid valve 75, C₂ Predetermined signals are output to the control duty solenoid valve 81, the ratio control (shift) linear solenoid valve 93, and the lockup control linear solenoid valve 97.
[0026]
Further, the control unit 100 is provided with a lockup detection unit 100a and a switching control unit 100b. The lockup detecting means 100a detects whether or not the lockup clutch 5 is currently engaged. In the continuously variable transmission, the map selected by the position sensor 66 is read from the accelerator sensor 65. This is detected by reading on the basis of the accelerator opening signal and the signal from the input rotational speed sensor 62. In the multi-stage automatic transmission, the lockup clutch is controlled by reading a map from the accelerator opening and the vehicle speed. The switching control means 100b switches the engine speed input to the control unit 100 between the signal from the engine speed sensor 65 and the signal from the input speed sensor 62, and the lockup detection means 100a locks up. When the clutch disengagement state is detected, the signal from the engine speed sensor 65 is directly input as the engine speed, and when the lockup clutch engagement state is detected, the input speed sensor 62 is detected. Is input as the engine speed.
[0027]
Next, the operation based on the above configuration will be described. A predetermined hydraulic pressure is generated by the rotation of the oil pump 21 based on the engine rotation. The hydraulic pressure is generated by the pressure control valve 72 based on a linear solenoid valve 75 controlled by a signal from the control unit 100 calculated based on a load torque or the like. By being controlled, the pressure is adjusted to the line pressure. Further, when line pressure is not required, such as in a stopped state, the solenoid valve 71 is controlled based on a signal from the control unit, and the oil pump control valve 70 is operated to the right half position to directly circulate the hydraulic pressure from the pump 21. To do.
[0028]
In the D range and L range of the manual valve 77, the hydraulic pressure from the port 1 is supplied to the first clutch hydraulic servo C1 via the port 2, and the first clutch C₁ Connect. In this state, the rotation of the engine output shaft 10 is caused by the torque converter 6, the input shaft 12, the one-way clutch F, and the first clutch C.₁ To the primary pulley 26, further to the secondary shaft 27 via the CVT 2 that is appropriately shifted, and to the left and right axles 60 and 61 via the counter gear and the differential device 9.
[0029]
When the manual valve 77 is in the D range, the first clutch C with the one-way clutch F interposed therebetween₁ Because only is connected, the engine brake does not operate during the coast. When the manual valve 77 is shifted to the L range, a duty signal is output from the control unit 100 to the solenoid valve 81 based on detection of the shift position, and C₂ By controlling the control valve 80, a predetermined pressure is applied to the hydraulic servo C2, and the second clutch C₂ Also connect. As a result, the coast-time engine brake operates. It should be noted that it is desirable that the transmission ratio of CVT 2 and the engagement point of the lock-up clutch are different between the D range and the L range with respect to the vehicle traveling situation (for example, throttle opening and vehicle speed).
[0030]
When the manual valve 77 is operated to the reverse range, the hydraulic pressure from the port 1 is supplied to the brake hydraulic servo B1 via the port 3. In this state, the ring gear R of the planetary gear 50 is locked, and the rotation of the sun gear S from the input shaft 12 is extracted as reverse rotation to the carrier CR, and the reverse rotation is transmitted to the primary pulley 26.
[0031]
In the CVT 2, the line pressure from the primary regulator valve 72 is supplied to the hydraulic actuator 35 of the secondary pulley 31, and the belt clamping force corresponding to the load torque acts. On the other hand, the linear solenoid valve 93 is controlled based on the shift signal from the control unit 100, the ratio control valve 92 is controlled by the output pressure from the solenoid valve, and the pressure regulation from the output port is controlled from the double piston of the primary pulley. Is supplied to the hydraulic actuator 33, and the gear ratio of the CVT 2 is controlled accordingly.
[0032]
The torque of the engine output shaft 10 is transmitted to the input shaft 12 via the torque converter 6, and particularly at the time of starting, the torque is changed by the torque converter 6 so that the torque ratio becomes high and transmitted to the input shaft 12. And start smoothly. Further, the torque converter 6 has a lock-up clutch 5, and the engine output shaft 10 and the input shaft 12 are directly connected to each other when the lock-up clutch is engaged during high-speed stable running. Thus, the loss due to the oil flow of the torque converter is reduced. Further, slip control is performed so that the rotational difference between the input side and the output side of the lockup clutch becomes a predetermined value in the low / medium speed region until the clutch is completely engaged.
[0033]
That is, the map is selected by the position sensor 66 depending on whether it is in the D range or the L range, and the accelerator opening from the accelerator sensor 65 and the input rotational speed point from the input rotational speed sensor 62 are read from the map and controlled. The lockup OFF signal or ON signal is output from the unit 100. When the output port 97a of the linear solenoid valve 97 outputs a lock-up OFF pressure (0 pressure) based on a signal from the control unit 100, the lock-up relay valve 96 is in the left half position and the lock-up control is performed. Valve 95 is also in the left half position. In this state, the line pressure of the line pressure oil passage Pl is supplied to the lockup OFF port 6a via the input port a and the output port b of the relay valve 96, and from the lockup ON port 6b to the port c of the relay valve 96. , D to the cller 99, whereby the lockup clutch 5 is held in the disconnected state. At this time, the line pressure of the line pressure oil passage Pl is led to the relay valve 96 via the input port e and the output port f of the control valve 95, but is blocked by the port g.
[0034]
On the other hand, when the linear solenoid valve 97 receives a lock-up ON signal from the control unit 100, an ON pressure is output from the output port 97a, and the lock-up relay valve 96 and the control valve 95 are switched to the right half position. In this state, the line pressure of the oil passage Pl is supplied from the port h of the relay valve 96 to the lockup ON port 6b via the port c, and from the lockup OFF port 6b to the ports b and g of the relay valve 96. Then, it is guided to the port f of the control valve 95 and discharged from the drain port, whereby the lockup clutch 5 is held in the connected state.
[0035]
When the lock-up clutch is slip-operated, the rotation speed on the input side and output side of the lock-up clutch, that is, the signal from the engine speed sensor 65 and the signal from the input speed engine 62 are input to the control unit 100. A signal is output so that the difference becomes a predetermined value. Based on this signal, the linear solenoid valve 97 outputs a predetermined hydraulic pressure lower than the ON pressure. Depending on the predetermined hydraulic pressure, the relay valve 96 is held in the left half position, that is, the lock-up ON position, and the hydraulic pressure communicating with the lock-up ON port 6b is supplied to the feedback oil chamber j of the control valve 95 via the port i. Has been. Further, a predetermined control pressure from the linear solenoid valve 97 acts on the control oil chamber k of the control valve 95, and the valve 95 controls the oil pressure of the feedback oil chamber j and the control oil chamber of the control oil chamber k. The port f communicates with the line pressure input port e and the drain port x at a predetermined rate. As a result, the hydraulic pressure from the lock-up OFF-side port 6a becomes a predetermined pressure, the ON-side oil chamber 5b and the OFF-side oil chamber 5a of the torque converter 6 are balanced, and the lock-up clutch 5 enters a predetermined slip state.
[0036]
In each control based on the signal from the control unit 100 described above, for example, the shift control output to the shift solenoid 93 and the line pressure control output to the line pressure solenoid 75, it is necessary to calculate the input torque. In addition to the accelerator opening, the input rotational speed and the output rotational speed, it is necessary to detect the engine rotational speed. Further, in the slip control of the lockup clutch, it is necessary to detect the engine speed in addition to the input speed.
[0037]
Next, the engine speed determination process will be described with reference to FIG. It is determined whether or not the lock-up detection means 100a of the control unit is in an engaged state of the lock-up clutch (S1). That is, the control unit 100 detects whether the lockup solenoid 97 outputs a lockup OFF signal or a lockup ON signal as described above. When the lock-up clutch 5 is in the non-engaged state (OFF signal output state), the signal from the engine speed sensor 65 is input as the engine speed (S2). On the other hand, when the lockup clutch is in the engaged state (ON signal output state), a signal from the rotational speed sensor (input rotational speed sensor) 62 of the primary sheave 23 is input and processed as the engine rotational speed (S3).
[0038]
As a result, during low-speed running when the lock-up clutch is disengaged, the engine speed is detected with high resolution and high accuracy based on the engine speed sensor 65 that detects a large number of irregularities (for example, 106) with an electromagnetic pickup. Detect numbers. Further, during high speed running with the lockup clutch engaged, the engine speed and the input speed are in an integral relationship, and a signal from the input speed (primary sheave speed) sensor 62 is input as the engine speed. To do. Therefore, by detecting a relatively small number of uneven portions (for example, 20) with an electromagnetic pickup, the count processing of the engine speed sensor 65 that detects the large number of uneven portions during high speed rotation is not required, and control is performed. Counter processing capacity can be secured.
[0039]
Further, it is desirable to use the slip control of the lock-up clutch even when starting.
[0040]
By monitoring the engine speed sensor 65, the input speed sensor 62, and the accelerator sensor 64, the engine speed Ne, the input speed Ni, and the throttle opening θ are read. Next, based on the engine speed Ne and the throttle opening θ, the engine torque Te is estimated by reading from the map. Further, based on the ratio of the input rotational speed Ni and the engine rotational speed Ne, the torque ratio t of the torque converter is estimated by reading from the map, and the input torque Ti (Ti = Te × t) is calculated based on the torque ratio. To do. On the other hand, an upper limit torque Tlim based on the capacity of the belt 32 and the torque capacity of the continuously variable transmission 1 limited by the axial force by the secondary hydraulic actuator 35 is set. Then, the calculated input torque Ti is compared with the set upper limit torque Tlim, and when Ti ≧ Tlim, the slip operation of the lockup clutch 5 is performed. As a result, for example, when the torque ratio of the torque converter 6 increases due to stall start or the like and exceeds the capacity of the continuously variable transmission 1, the lock-up clutch 5 slips (the lock-up clutch is completely engaged). In this state, the torque ratio becomes 1), and the torque ratio of the torque converter 6 is restricted from increasing, and the torque of the input shaft 12 is suppressed within the torque capacity of the continuously variable transmission. That is, a range in which the torque Ti of the input shaft during the slip operation calculated by the controller 100 does not exceed the upper limit torque of the continuously variable transmission based on the engine speed Ne, the input shaft speed Ni, and the throttle opening θ. Thus, the linear solenoid valve 97 is controlled by feedback control so that the lock-up clutch 5 is slip-operated.
[0041]
When performing the slip control at the time of starting, it is necessary to detect the engine rotational speed with high accuracy during low-speed traveling. However, as described above, the engine with high resolution at low speed while ensuring sufficient counter capacity at high speed. Since the number of rotations can be detected, it is possible to sufficiently meet the above requirements.
[0042]
Similarly, control that requires highly accurate detection of the engine speed during low-speed traveling, such as creep prevention control and reverse inhibition control, can be sufficiently handled. Moreover, although the above-mentioned embodiment has described the continuously variable automatic transmission, this is an automatic transmission that switches the transmission system path of the transmission gear to multiple stages by switching the clutch and the brake by a signal from the control unit. Of course, the present invention can be similarly applied.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a continuously variable transmission according to the present invention.
FIG. 2 is a diagram showing the hydraulic circuit.
FIG. 3 is a diagram showing an electric control portion thereof.
FIG. 4 is a flowchart showing engine speed determination processing.
[Explanation of symbols]
1 continuously variable transmission
2 Belt type continuously variable transmission (CVT)
5 Lock-up clutch
6 Torque converter
10 Engine output shaft
12 Input shaft
60, 61 axle
62 Input (primary sheave) speed means (sensor)
63 Output (secondary sheave) rotation speed means (sensor)
65 Engine speed (sensor)
100 control unit
100a Lock-up clutch detection means
100b switching control means

Claims (3)

In an automatic transmission for a vehicle, wherein torque from an engine is transmitted to a transmission via a torque converter having a lock-up clutch, and further torque transmitted by the transmission is transmitted to an axle.
Input rotational speed detection means for detecting the input rotational speed of the transmission,
Engine speed detecting means for detecting the engine speed at a higher resolution than the input speed detecting means;
Lock-up detection means for detecting whether the lock-up clutch is fully engaged or other non-engaged state;
When the lock-up detection means detects a non-engagement state of the lock-up clutch, the signal from the engine speed detection means is input as an engine speed, and the lock-up clutch is engaged. Switching control means for switching so as to input the signal from the input rotational speed detection means as the engine rotational speed,
A control device for an automatic transmission for a vehicle, comprising: The lock-up clutch is slip controlled ,
In the slip control, the switching control means inputs a signal from the engine speed detecting means as an engine speed,
The control device for an automatic transmission for a vehicle according to claim 1. The transmission is a belt type continuously variable transmission,
The control device for an automatic transmission for a vehicle according to claim 1 or 2.

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