JP2540455B2 - Control method for direct coupling mechanism of hydraulic power transmission device of automatic transmission for vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a direct connection mechanism control method for a hydraulic power transmission device of an automatic transmission for a vehicle.

(Prior Art and Problems Thereof) Generally, a vehicle equipped with an automatic transmission has a sufficient driving force and a smooth and easy driving feeling with a small number of gear stages due to a torque amplifying action of a fluid power transmission device, for example, a fluid torque converter. However, due to the fluid slip loss of the torque converter, the practical fuel consumption was poor, and the engine rotation speed increased by the amount of the fluid slip, and the operating noise was loud and the quietness was lacking.

For this reason, when it is not necessary to expect the torque amplification function of the torque converter, the input / output members of the torque converter are mechanically coupled to improve the power transmission efficiency, which is a so-called lock-up mechanism. A mechanism (hereinafter referred to as a direct-coupling mechanism) has been conventionally developed and has already been put into practical use. Since this can obtain a favorable effect from the improvement of power transmission characteristics and fuel efficiency, the direct-coupling mechanism should be selected from the low speed operation range as much as possible. It is desirable to make it work. However, if the torque converter is directly connected in the low-speed operation range where the engine rotation speed is also low, the torque fluctuation of the engine is large, which causes vibration and noise of the vehicle body or deteriorates the driving performance. .

Therefore, in such a low speed operation range, the torque converter is not directly connected, but the slip amount of the direct connection mechanism is set to the transmission capacity of the direct connection mechanism so that the direct connection mechanism slides with respect to the peak value of the torque fluctuation. That is, control is performed by adjusting the engagement force. Specifically, this type of control method calculates, for example, a rotational speed ratio e or a slip ratio (1-e) between the input member and the output member of the torque converter as a parameter representing the slip amount, and the low speed operation is performed. In the range, the optimum transmission capacity value is selected from a plurality of transmission capacity values of the direct coupling mechanism according to the actual measurement value of the rotation speed ratio e or the slip ratio so that the rotation speed ratio e is 1 or the slip ratio is not 0. This is adopted to feedback control the transmission capacity of the direct coupling mechanism.

However, when such a control method is implemented, the following problems occur. That is, for example, when the solenoid valve for controlling the transmission capacity in the embodiment of the present invention described later is off, that is, when the valve is closed, the transmission capacity (the transmission capacity becomes the maximum capacity of the control system) is relatively weak. If it is set to, the control will be performed smoothly and vibration and noise of the vehicle body will not be generated, but the fuel consumption will be deteriorated, and conversely, in order to improve the fuel consumption, the transmission capacity will be relatively strong. If set, sometimes the rotation speed ratio e
1 or the slip ratio approaches 0, or instantaneously the rotational speed ratio e = 1 or the slip ratio = 0, so that vibration and noise of the vehicle body are generated.

This is because the rotation speed ratio e
Alternatively, it takes some time to calculate the slip ratio including the data sampling time, and the feedback system has mechanical parts such as hydraulic equipment.Therefore, the response time of the control system should be faster than a certain value. While there is a physical limit that there is not, when the transmission capacity is set to a high value, the control speed is delayed because the transition speed in the direct connection direction (transmission capacity increasing direction) increases. e, or the slip ratio exceeds the reference range value,
Reflecting this result, the control starts to reduce the transmission capacity more than necessary to return to the reference range value next time.
The operation in which the rotation speed ratio e or the slip ratio is drastically reduced again and becomes equal to or less than the reference range value is repeated, and diverges in the worst case.

It should be noted that if the response time of the entire control system is shortened, the above problem may not occur even if the transmission capacity is set to a strong value, but in reality there is a limit to the reduction of the response time.

In order to solve the above-mentioned inconvenience, the PI used in the feedback control according to the magnitude of the error between the target slip amount (target slip amount) of the torque converter and the actual slip amount.
A method for changing the parameters of D calculation is disclosed in Japanese Patent Laid-Open No. 60-1460.
It is proposed by the publication. However, according to this proposed method, when the error is smaller than the set value, the value of the parameter is simply set to a small predetermined value to reduce the change gradient of the slip correction amount, and the slip amount at each time point is reduced. However, there is a drawback in that it is not possible to adequately respond to the size and the change state thereof and detailed control cannot be performed.

Further, as described above, in order to solve the problem that when the torque converter is completely directly connected in the low speed operation region of the vehicle, vibration and noise of the vehicle body occur and driving performance deteriorates, the internal pressure of the torque converter is adjusted according to the increase in vehicle speed. In order to control the operation of the direct coupling mechanism continuously and smoothly, the engaging force of the direct coupling mechanism is gradually increased according to the increase of the vehicle speed by controlling so as to decrease continuously. It is proposed by the publication. However, since this method does not control the slip ratio to a target value (reference range value) in correspondence with the vehicle speed, it is possible to control the slip amount of the direct coupling mechanism, that is, the slip ratio to an optimum value corresponding to the vehicle speed. However, there is a drawback in that the fuel economy and power transmission characteristics cannot be sufficiently improved.

(Object of the Invention) The present invention has been made in view of the above circumstances, and a method for controlling a direct coupling mechanism of a fluid power transmission device for an automatic transmission for a vehicle, which is capable of improving fuel consumption and power transmission characteristics according to a vehicle speed. The purpose is to provide.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention is directed to a predetermined amount of relative slip between the input and output members of a fluid type power transmission device having an input member and an output member. Parameter value (e)
Is a vehicle automatic transmission that variably controls the transmission capacity of a direct coupling mechanism that mechanically engages the input and output members so that the values are within a reference value region having preset upper and lower limits. In the method for controlling a direct coupling mechanism of a fluid type power transmission device, the vehicle speed (U) is detected, and the upper limit value and the lower limit value of the reference value region are set according to the detected vehicle speed. It is a thing.

(Embodiment) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an outline of an automatic transmission for a vehicle to which the present invention is applied. The output of an engine E is from a crankshaft 1 to a torque converter T as a hydraulic power transmission device, an auxiliary transmission M, and a differential device Df. Is sequentially transmitted to the left and right drive wheels W and W ′, and these are driven.

The torque converter T includes a pump impeller 2 which is an input member connected to the crank shaft 1, a turbine impeller 4 which is an output member connected to the input shaft 3 of the auxiliary transmission M, and a relative rotation on the input shaft 3. And a stator shaft 5a supported by a stator impeller 5 connected to the stator shaft 5a via a one-way clutch 6. The torque transmitted from the crankshaft 1 to the pump impeller 2 is hydrodynamically transmitted to the turbine impeller 4, and when the torque is amplified during this period, as is well known, the stator impeller 5 reacts with its reaction force. To bear.

A pump drive gear 7 for driving the hydraulic pump P of FIG. 2 is provided at the right end of the pump impeller 2, and the stator shaft 5a
A stator arm 5b for controlling the regulator valve Vr shown in FIG. 2 is fixedly installed at the right end of the.

A roller type direct coupling clutch Cd is provided between the pump impeller 2 and the turbine impeller 4 as a direct coupling mechanism capable of mechanically coupling them. Explaining this in detail with reference to FIGS. 2 and 3, an annular drive member 9 having a drive conical surface 8 on the inner periphery is spline-fitted to the inner peripheral wall 2a of the pump impeller 2. Further, an annular driven member 11 having a driven conical surface 10 facing the driving conical surface 8 in parallel to the outer periphery is spline-fitted axially slidably on the inner peripheral wall 4a of the turbine impeller 4. . A piston 12 is integrally formed at one end of the driven member 11, and the piston 12 is slidably engaged with a hydraulic cylinder 13 provided on an inner peripheral wall 4a of the turbine impeller 4, and the internal pressure of the cylinder 13 and the torque converter T are connected to each other. Both left and right end faces are subjected to internal pressure at the same time.

A cylindrical clutch roller 14 is interposed between the driving and driven conical surfaces 8 and 10, and the clutch roller 14 has a central axis o between the conical surfaces 8 and 10 as shown in FIG. It is held by an annular retainer 15 so as to be inclined at a constant angle θ with respect to a generatrix g of an imaginary conical surface Ic (see FIG. 2) passing through.

Therefore, when the hydraulic pressure higher than the internal pressure of the torque converter T is introduced into the hydraulic cylinder 13 at the stage where the torque amplifying function of the torque converter T is no longer necessary, the piston 12, that is, the driven member 11 is pushed toward the drive member 9. It As a result, the clutch roller 14 is pressed against the conical surfaces 8 and 10. At this time, when the driving member 9 is rotated by the output torque of the engine E with respect to the driven member 11 in the X direction in FIG.
Since 14 has its central axis o inclined as described above, its rotation gives relative axial displacement to both members 9 and 11 to bring them closer to each other. As a result, the clutch roller 14 bites between the conical surfaces 8 and 10, and the members 9 and 11
The pump impeller 2 and the turbine impeller 4 are mechanically connected to each other. Even when the direct coupling clutch Cd operates in this way, the output torque of the engine E exceeds the coupling force and the two-wheeled vehicle 2,4
If it joins in between, the clutch roller 14 is
A slip occurs on 10 and the above torque is divided into two parts, a part of the torque is mechanically transmitted through the direct coupling clutch Cd, and the remaining torque is hydrodynamically transmitted from the pump impeller 2 to the turbine impeller 4. As a result, the ratio between the former torque and the latter torque changes depending on the degree of slippage of the clutch roller 14.

When a reverse load is applied to the torque converter T in the operating state of the direct coupling clutch Cd, the rotational speed of the driven member 11 becomes higher than the rotational speed of the driving member 9, so that the driving member 9 is relatively relative to the driven member 11. 3, the clutch roller 14 rotates in the direction opposite to the previous direction and rotates relative to the Y direction in FIG. 3, thereby imparting a relative axial displacement to both members 9 and 11 so as to separate them from each other. As a result, the clutch roller 14 is released from the bite between the conical surfaces 8 and 10, and is put in a idling state. Therefore, the transmission of the reverse load from the turbine impeller 4 to the pump impeller 2 is performed hydrodynamically only.

When the hydraulic pressure of the hydraulic cylinder 13 is released, the piston 12 receives the internal pressure of the torque converter T and retracts to the initial position, so that the direct coupling clutch Cd is deactivated.

Referring again to FIG. 1, a first speed gear train G ₁ and a second speed gear train G1 are provided between the input and output shafts 3 and 16 of the auxiliary transmission M which are parallel to each other.
G _2, the third-speed gear train G _3, the fourth speed gear train G _4, and the reverse gear train
Gr is provided in parallel. The first speed gear train G ₁ can be connected to the drive gear 17 connected to the input shaft 3 via the first speed clutch C ₁ and the output gear 16 meshing with the drive gear 17 via the one-way clutch Co. And a driven gear 18. The second speed gear train G ₂ is a drive gear 19 that can be connected to the input shaft 3 via a second speed clutch C _2.
And a driven gear 20 that is fixed to the output shaft 16 and meshes with the gear 19. The third speed gear train G ₃ includes a drive gear 21 fixedly mounted on the input shaft 3 and a driven gear 22 which is connected to the output shaft 16 via a third speed clutch C ₃ and is meshable with the gear 21. . The fourth speed gear G ₄ is a driven gear 23 that is connected to the drive gear 23 that is connected to the input shaft 3 through the fourth speed clutch C ₄ and that is connected to the output shaft 16 through the switching clutch Cs and that meshes with the gear 23.
Consists of 24. Further, the reverse gear train Gr is the fourth speed gear train G ₄
Drive gear 25 that is integrally provided with the drive gear 23, and a driven gear that is connected to the output shaft 16 via the switching clutch Cs.
26 and an idle gear 27 meshing with both gears 25, 26. The switching clutch Cs is a driven gear of the fourth speed gear train G ₄ .
The clutch Cs is provided between the idle gear 24 and the idle gear 27.
1, the driven gear 24 and the idle gear 27 can be selectively connected to the output shaft 16 by shifting the selector sleeve S of FIG. 1 to the left forward position or the right backward position. The one-way clutch Co operates from the engine E to the drive wheels W,
Only drive torque to W'is transmitted, not torque in the opposite direction.

Thus, when the selector sleeve S is held at the forward position as shown in FIG. ₁ , if only the first speed clutch C ₁ is connected, the drive gear 17 is connected to the input shaft 3 and The speed gear train G ₁ is established, and the input shaft 3 is connected via this gear train G _1.
The torque is transmitted from the output shaft 16 to the output shaft 16. Then stay connected to the first speed clutch C _1, by connecting the second speed clutch C _2, the second-speed gear train G ₂ is established that the driving gear 19 is coupled to the input shaft 3, the gear Torque is transmitted from the input shaft 3 to the output shaft 16 via the row G ₂ . At this time, the first speed clutch C ₁
Is engaged, but the action of the one-way clutch Co does not result in the first speed, but the second speed gear train G ₂ is established.
The same applies to the fourth speed and the fourth speed. If the second speed clutch C ₂ is released and the third speed clutch C ₃ is connected, the driven gear 22
Is connected to the output shaft 16 to establish the third speed gear train G _{3, and} when the third speed clutch C ₃ is released and the fourth speed clutch C ₄ is connected, the driving gear 23 is connected to the input shaft 3. The fourth speed gear train G ₄ is established by being connected. Further, by moving the selector sleeve S of the switching clutch Cs to the right in FIG. 1 and connecting only the fourth speed clutch C ₄ , the drive gear 23 thereof is connected to the input shaft 3,
The driven gear 24 is connected to the output shaft 16 to establish the reverse gear train Gr, and the reverse torque is transmitted from the input shaft 3 to the output shaft 16 via the gear train Gr.

The torque transmitted to the output shaft 16 is transmitted from the output gear 28 provided at the end of the shaft 16 to the large diameter gear D _G of the operating device Df. One end of a speedometer cable 30 is fixed to a gear 29 meshing with a gear Ds fixed to the gear D _G , and the other end of the speedometer cable 30 is connected to a speedometer 32 via a magnet 31a of a vehicle speed detector 31. , And the speedometer 32 is driven through the gears Ds, 29 and the cable 30 to display the vehicle speed. Further, the vehicle speed detector 31 is composed of the magnet 31a and, for example, a reed switch 31b driven by the magnet 31a, and the reed switch 31b is opened and closed by the magnet 31a rotating together with the speedometer cable 30. The off signal is supplied to the electronic control unit 33 described later.

FIG. 2 shows a hydraulic control circuit of an automatic transmission for a vehicle to which the present invention is applied.

In the figure, the hydraulic pump P whose suction port is connected to the oil tank R has an inlet port 6 of the regulator valve Vr via an oil passage 300.
0a, a pilot pressure introducing port 60b, a manual shift valve (hereinafter simply referred to as a manual valve) Vm, a port 70b, and a governor valve Vg, an inlet port 80a, respectively. Manual valve V
The ports 70a and 70c of m are connected to the ports 90c and 90b of the servo piston 90 via the oil passages 301 and 302, respectively.
To the port 70d of the manual valve Vm, the inlet port 270a of the pressure reducing valve 270 and the port 100a of the throttle valve Vt, and the port 70
The e is connected to the port 70g of the manual valve Vm, the port 210d of the timing valve 210, the port 170a of the first accumulator 170, and the second speed clutch C ₂ via the oil passage 304, respectively. Further, the port 70f of the manual valve Vm is connected to the port 130b of the _second shift valve V ₂ via the oil passage 305 in which the throttle 350 and the one-way valve 380 are connected in parallel, and the port 70h is throttled 359 in the middle. And a one-way valve 383 are connected to the first speed clutch C ₁ via oil passages 313 provided in parallel. Two inlet ports of the flow rate adjusting valve 400 are provided in the oil passage 313 via an oil passage 307 provided with a throttle 369.
400a, 400b are connected, and one outlet port 400d of the flow rate adjusting valve 400 is a port of the first shift valve V ₁ via the oil passage 307a.
Connected to 120b. First inlet port 4 of flow control valve 400
A throttle 370 is provided between 00a and the oil passage 307.

The port 70i of the manual valve Vm is connected to the port 90a of the servo piston 90 via the oil passage 308, the port 70k is connected to the port 210e of the timing valve 210 via the oil passage 309, and the second accumulator 1
The port 70a of 90 and the fourth speed clutch C ₄ , the port 70m through the oil passage 310, the port 70n of the manual valve Vm, the port 130d of the _second shift valve V2, and the port 160 of the first control valve 160.
connected to b respectively. A throttle 356 and a one-way valve 381 are arranged in parallel with each other between the oil passage 310 and the port 130d of the _second shift valve V2.

The ports 100b and 100c of the throttle opening response valve Vt are connected to the first to third accumulators 170, 190, 180 via the oil passage 311.
Ports 170b, 190b, 180b, modulator valve 220 port 220f, on-off valve 230 port 230c, flow rate adjustment valve 400
Port 400c of the first control valve 160, the port 160a of the first control valve 160, and the port 200a of the second control valve 200, respectively.
52 is inserted. Throttle opening valve Vt port 100d
Are connected to the port 130g of the second shift valve V ₂ and the drain EX via the oil passage 312, and the throttle 353 is interposed between the oil passage 312 and the drain EX. Port 110a of the third control valve 110
Are connected to the port 120a of the first shift valve V ₁ and the drain EX via an oil passage 315, respectively, and a throttle 354 is interposed between the oil passage 315 and the drain EX.

Ports 120c and 120d of the first shift valve V ₁ are oil passages 316 and 3 respectively.
17 to the ports 130a and 130c of the second shift valve V ₂ and the port 120e to the port 16 of the first control valve 160 via the oil passage 318.
0c and drain EX respectively connected to the oil passage 318 and drain EX
A diaphragm 355 is interposed between and. The port 130e of the second shift valve V _{2 is} a port of the second control valve 200 via the oil passage 319.
200c and drain EX respectively connected to the oil passage 319 and drain E
A diaphragm 357 is provided between the diaphragm and X. The port 130f of the second shift valve V ₂ is connected to the port 200 of the second control valve 200 via an oil passage 320 in which a throttle 358 and a one-way valve 382 are connected in parallel.
b, are respectively connected to the ports 180a and the third speed clutch C ₃ of the third accumulator 180. Incidentally, while the aperture 356a is interposed among the second two EX port of the shift valve V _2.

The port 120f of the first shift valve V ₁ is connected to the input port 140a of the first solenoid valve 140 via the oil passage 340, and the oil passage 340 of the pressure reducing valve 270 is connected via the oil passage 341 provided with the throttle 361. Connected to exit port 270b. The port 130h of the second shift valve V ₂ is connected to the inlet port 150a of the second solenoid valve 150 via the oil passage 322a, and the oil passage 322a is connected to the oil passage 322 via the throttle 362.
This oil passage 322 is connected to the outlet port 80b of the governor valve Vg.
Connected to.

When the solenoids 142 and 152 are deenergized (OFF), the valve elements 141 and 151 of the first and second solenoid valves 140 and 150 are pressed by the spring force of the springs 143 and 153 to close the inlet ports 140a and 150a, and the solenoids 142 and 152 are energized (ON). ) At times, it is sucked against the spring force and opens the inlet ports 140a, 150a. That is, the first and second solenoid valves 140 and 150 are solenoids 142 and 152.
Is closed when it is deenergized and opened when it is energized.

The outlet port 60c of the regulator valve Vr is connected to the port 210a of the timing valve 210 and the port 230d of the on-off valve 230 via an oil passage 325, respectively. The port 210b of the timing valve 210 is connected to the port 220d of the modulator valve 220 via the oil passage 321 provided with the throttle 371 in the middle, the port 210c is connected to the port 220a of the modulator valve 220 via the oil passage 327, and the port 210f is connected to the middle. The oil passages 501a provided with the throttles 375 are connected to the oil passages 501, respectively. The port 220b of the modulator valve 220 is connected to the oil passage 326 via an oil passage 326a provided with a throttle 372 in the middle, and the port 220c is connected to the on-off valve 230 via an oil passage 353 provided with a throttle 373 in the middle. The port 230b and the port 220e are connected to an oil passage 322 provided with a throttle 366a on the way. On-
The port 230a of the off valve 230 is connected to the oil passage 326, and the port 230e is connected to the oil passage 334 via the oil passage 501 provided with the throttle 374 on the way.

The inlet port 240a of the third solenoid valve 240 is connected to the oil passage 326 via the throttle 367. The valve body 241 of this third solenoid valve 240
Is pressed by the spring force of the spring 243 when the solenoid 242 is deenergized (OFF) to close the inlet port 240a,
When the 242 is energized (ON), it is sucked against the spring force and opens the inlet port 240a. That is, the third solenoid valve 240 is closed when the solenoid 242 is deenergized and opened when energized.

The port Ta of the torque converter T is connected to the oil passage 325 via the oil passage 334 provided with the throttle 368, and the port Tb is connected to the oil passage 326.
The port Tc is the inlet port 250a of the pressure maintaining valve 250 via the oil passage 335.
Connected to. The pilot pressure introducing port 250b of the pressure maintaining valve 250 is connected to the upstream side of the throttle 366a of the oil passage 322 via the oil passage 336, and the outlet port 250c is connected to the drain EX via the oil passage 337 and the oil cooler 260, respectively. Each of the drains EX is connected to an oil tank R.

Solenoids 142, 1 of the first to third solenoid valves 140, 150, 240
52 and 242 are connected to the electronic control unit 33 via signal lines 142a, 152a and 242a, respectively. The electronic control unit 33 is a vehicle speed detector.
31, engine speed detector 34, and gear position detector 35
The first and second solenoid valves 140 and 150 are controlled according to a predetermined shift map based on input signals from the
Speed to fourth speed engagement of the clutch C ₁ -C _4, for shift control by controlling the disengaged (dissection). Further, the electronic control unit 33 actually measures a predetermined parameter value representing the relative slip amount of the torque converter T and the output member, for example, a speed ratio e, and compares the measured value e with a predetermined reference value. Based on the comparison result, the engagement force (transmission capacity) of the direct coupling clutch Cd is determined and the third solenoid valve 240 is controlled to control the engagement force of the direct coupling clutch Cd.

 The operation of the above hydraulic circuit will be described below.

The hydraulic pump P sucks and pressurizes the hydraulic oil in the oil tank R, regulates it to a predetermined pressure (hereinafter referred to as line pressure Pl) by a regulator valve Vr, and then feeds it to the oil passage 300. Regulator valve V
The stator arm 5b (see FIG. 1) is in contact with the spring receiver 61 of r, and when the reaction force of the stator impeller 5 of the torque converter T exceeds a predetermined value, the spring 62 is compressed to compress the hydraulic pump P.
Increase the discharge pressure of. Such hydraulic control is disclosed in JP-B-45-3086.
It is described in detail in No. 1. A part of the hydraulic oil regulated by the regulator valve Vr is sent into the torque converter T via an inlet oil passage 334 having a throttle 368 to pressurize the inside thereof so as to prevent cavitation, and then a pressure holding valve 250, It is returned to the tank R via the oil cooler 260. The pressure-holding valve 250 causes the spool 251 to move to the spring 2 at the governor pressure P _{G as the} vehicle speed U increases.
It moves to the right side in the figure against 52 and releases the internal pressure of the torque converter T to the oil tank R. That is, the pressure maintaining valve 250 functions to reduce the internal pressure of the torque converter T in proportion to the vehicle speed U, and since the spool 251 thereof operates by the differential pressure from the governor pressure P _G , the transmission capacity of the direct coupling clutch Cd increases. The maximum transmission capacity of the direct coupling clutch Cd is increased on the high speed side.

The manual valve Vm is switched by the manual switching operation of the shift lever, and P (parking), R (reverse), N (neutral), D ₄ (forward 4 speed automatic shift), D ₃ (forward 3 except TOP)
It has six shift positions (automatic gear shift) and 2 (2ND hold), and an operation mode corresponding to each shift position is arbitrarily selected. When the spool 71 of the manual valve Vm is at the illustrated N position, the port 70b connected to the oil passage 300 is blocked by the spool 71 of the manual valve Vm, and the other port 70 is blocked.
a, 70C～70n the first speed to fourth speed four clutches C ₁ -C ₄ are connected to all the drain EX is placed all disengage, thus the torque of the engine driven wheels W, W ' (See FIG. 1).

When the spool 71 of the manual valve Vm is moved one frame to the left from the illustrated position and is in the D ₄ position, the oil passages 302 and 313 both communicate with the oil passage 300 to supply pressure oil, and the oil passages 305 and 304 respectively communicate with each other. To meet each other. The oil passage 309 communicates with the oil passage 310, but is isolated from the drain EX and the oil passage 308, respectively, and the oil passage 301 continues to communicate with the drain EX. As a result, D ₄ position (range)
Then, the servo piston 90 for moving the selector sleeve S (see FIG. 1) receives the line pressure Pl in its spring chamber 92 and is hydraulically fixed to the spool 91 at the position shown in the drawing. It is held in the position shown in FIG. 1 by a shift fork 39 fixed to one end of 91. As a result, the fourth speed driven gear 24 moves the switching clutch Cs.
The reverse driven gear 26 is rotatably placed in the engaged state with.

From this state, even if the spool 71 of the manual valve Vm is moved one frame to the left and placed in the D ₃ position, the oil passage 310 will not be
The connection relationship of the oil passages connected to the manual valve Vm does not change except that the oil passages are connected to the drain EX via. At these 2, D ₃ , and D ₄ positions, pressure oil is sent to the throttle opening response valve Vt via the oil passage 303. The throttle opening responsive valve Vt is a parameter representing the load of the engine E and is proportional to the depression amount of a throttle pedal (not shown), that is, the valve opening of a throttle valve (not shown) provided in the intake system of the engine E. And a cam that rotates counterclockwise from the position shown
The left side spool 101 receives the displacement of 104 via the spring 103.
To the left to open port 100a to the output side and output port 10
The discharge pressure of 0c is applied to the port 100b via the throttle 352 to move the spool 101 to the right to drive the port 100a to the closing side, and the pressure proportional to the opening degree of the throttle valve in the output oil passage 311. (Hereinafter referred to as throttle pressure Pt) is generated. The counterclockwise rotation of the cam 104 moves the spool 102 on the right side to the left to continuously reduce the communication between the port 100d and the drain EX, and kicks down from the third speed (3RD) to the second speed (2ND). Alleviate the shift shock at the time.

The cam 113 of the third control valve 110, which is interlocked with the cam 104, rotates counterclockwise according to the valve opening of the throttle valve to move the spool 111 to the left against the spring force of the spring 112, and the port 110a.
Continuously squeezes the communication between the Drain EX and the drain EX to mitigate the shift shock at the time of kickdown from the 4th speed (TOP) to the 3rd speed (3RD). Further, the throttle pressure Pt is sent to the port 400c of the flow rate adjusting valve 400 via the oil passage 311, and controls the valve 400. That is, when the flow rate adjusting valve 400 is in the illustrated state, the oil passage 307
From the outlet port 400d through the first inlet port 400a provided with the throttle 370 to the first shift valve via the oil passage 307a.
The hydraulic pressure is sent to the port 120b of V _{1 and} the throttle pressure
When Pt increases and overcomes the force of the spring 402, the spool 401 moves to the left and passes through both the first and second inlet ports 400a and 400b, thereby supplying pressure oil from the outlet port 400d to the oil passage 307a. When the throttle valve opening is small, the amount of the clutch is increased and the clutch is entangled. (Two clutches are engaged with each other, and energy is consumed in both clutches. In order to prevent the above), the action to prevent the next clutch from being engaged until one clutch is completely disengaged, for example, to mitigate the shock of upshift when the accelerator is released or downshift when the vehicle is stopped.

The oil discharged from the hydraulic pump P is the inlet port 80a of the governor valve Vg.
The governor valve Vg is rotated by its own shaft 82 at a speed proportional to the vehicle speed by the gear 81 meshing with the large diameter gear D _G shown in FIG. The pressure (hereinafter referred to as governor pressure P _G ) proportional to is output.

When the first shift valve V ₁ is in the illustrated first position, it connects the input oil passage 307a to the output oil passage 316, and the other output oil passage 317
Is connected to drain EX via oil passage 318. The valve body 121 of the first shift valve V ₁ is shifted to the first position by the spring 122. The first shift valve V ₁ has an oil passage in the chamber 120A facing the right end surface.
A spring is generated by the hydraulic pressure reduced to a pressure lower than the line pressure Pl introduced from the pressure reducing valve 270 via the pressure reducing valve 270, the throttle 361, and the oil passage 340.
It can be moved leftward against the spring force of 122 to take the second position, and when in this second position, the output oil passage 316 is changed to the oil passage 315.
Connect to the drain EX via the other output oil passage 317 and oil passage 318
And is connected to the input oil passage 307a.

When the first shift valve V ₁ is in either the first or second position, the oil passage 313 is connected to the first speed (LOW) clutch C ₁ , and therefore the manual valve Vm is set to D ₃ Alternatively, when in the D ₄ position, the first speed clutch C ₁ is always in pressure engagement. The spool 121 of the first shift valve V ₁ is controlled by a first electromagnetic valve 140, and when the electromagnetic valve 140 is closed, the spool 121 is moved to the second position by the pressure introduced into the chamber 120A, and when opened, the spring 122 is opened. To take the first position.

When the second shift valve V ₂ is in the illustrated first position, it blocks the input oil passage 316 and connects the output port 130d to the drain EX, the input oil passage 317 to the output oil passage 305, and the output oil passage 320.
Is connected to drain EX via oil passage 312. The spool 131 of the second shift valve V ₂ is shifted to the first position by the spring 132. This shift valve V ₂ resists the spring force of the spring 132 by the governor pressure P _G introduced from the port 130h to the chamber 130A facing the right end surface of the spool 131 via the oil passage 322, the throttle 362 and the oil passage 322a. When it is in the second position by being moved leftward, the output port 130d is disconnected from the drain EX and connected to the input oil passage 316, and the output oil passage 305 is connected to the drain EX via the oil passage 319 when in the second position. The remaining output oil passage 320 is disconnected from the oil passage 312 and is switched and connected to the input oil passage 317. The spool 131 of the second shift valve V ₂ is controlled by the second solenoid valve 150, and when the solenoid valve 150 is closed, the governor pressure P _G introduced into the chamber 130A moves the second position, and when the solenoid valve 150 is opened, the spool 131 is opened. The spring 132 takes the first position.

Further, the second shift valve V ₂ is particularly provided with the click motion mechanism 133 so that the switching operation thereof is performed on / off. The click motion mechanism 133 responds to the change in the governor pressure P _G even when the second solenoid valve 150 is closed, and changes the spool position of the shift valve V ₂ to the first or second position.
It works only for one of the positions.

Now, as long as the engine E is rotating, the hydraulic oil pressurized by the hydraulic pump P is sent to the governor valve Vg, and the governor valve Vg
In conjunction introduced into the second chamber 130A of the shift valve V ₂ pressure is regulated as a signal pressure proportional to the vehicle speed U, pressure reducing valve 270 is introduced to the first shift valve V ₁ of the chamber 120A is depressurized. Manual valve
These two shift valves V ₁ , V when Vm is in the D ₄ (or D ₃ ) position
_Two solenoid valves 14 to hold ₂ in the first switching position shown
The solenoids 142 and 152 of 0 and 150 may be urged together and opened. As a result, the second to fourth clutches C ₂ ~
C ₄ without pressurized, only the first speed clutch C ₁ is engaged pressurized pressure coefficient, the reduction ratio of the first speed is established. Since the first speed generally covers a low speed region, the governor pressure P _G itself is also a low pressure in this low speed region, and the second solenoid valve 150 to the oil tank R passes through the throttle 362. The loss flow rate of the pressure oil to be discarded is also small and economical. This is particularly advantageous when the pressure of the entire system has to be kept considerably higher than the normal pressure level (line pressure Pl), such as when the vehicle is stalled (vehicle speed = 0).

Next, the solenoid 152 of the second solenoid valve 150 is energized to keep the solenoid valve 150 in the open state, and the first solenoid valve 140
When the solenoid 142 is deenergized and the solenoid valve 140 is closed,
Hydraulic pressure is decompressed by the pressure reducing valve 270 is generated in the first shift valve V ₁ of the chamber 120A, thereby the spool 121 of the shift valve V ₁ against the spring force of the spring 122 is moved to the left. The oil passage 307a by leftward movement of the spool 121 is connected to the oil passage 305 through the oil passage 317, oil passage 305 through the notch 71a and the port 70g of the port 70f, the spool 71 of the manual valve Vm when the D ₄ position Oil passage
304, and when in the D ₃ position, they are connected to the oil passage 304 via the port 70f, the annular groove 71b of the spool 71, and the port 70e, respectively, and the second speed clutch C ₂ is pressure-engaged. Therefore, D ₄ or D ₃ first speed clutch at the position C ₁ and the second speed clutch C ₂ is engaged pressurized pressure coefficient. However, as shown in FIG. 1, between the first speed driven gear 18 and the output shaft 16, a one-way clutch C _{0 for} transmitting torque only in the driving torque direction from the engine E is interposed. The second speed reduction ratio is established.

Next, when the solenoid 142 of the first solenoid valve 140 is deenergized to close the solenoid valve 140 and the solenoid 152 of the second solenoid valve 150 is deenergized to close the solenoid valve 150, The governor pressure P _G at that time is generated in the chamber 130A of the second shift valve V ₂ and the spring
The spool 131 moves to the left and takes the second position only when the left force by the governor pressure P _G exceeds the resistance force by the 132 and the click motion mechanism 133. By the left movement of the spool 131, the oil passage 305 is connected to the drain EX via the oil passage 319 and the engagement of the second speed clutch C ₂ is released, and at the same time, the oil passage 320 is changed to the oil passage 317 which is a hydraulic pressure source. It is connected and the third speed clutch C ₃ is pressure-engaged. At this time as well, the first speed clutch C ₁ is pressure-engaged, but the action of the one-way clutch C ₀ establishes the reduction ratio of the third speed.

Next, when the solenoid 152 of the second solenoid valve 150 is kept deenergized and the solenoid 142 of the first solenoid valve 140 is re-energized to open the solenoid valve 140, the first shift valve The spool 121 of V ₁ moves right and returns to the position shown,
318 is released engagement of the third speed clutch C ₃ is connected to the drain EX via the same time it connects the oil passage 316 to the hydraulic pressure source 307a, to supply the pressure oil to the oil passage 310. When the oil passage 310 is in the D ₄ shift position, it is connected to the oil passage 3 via the ports 70m and 70k of the manual valve Vm.
It is connected to 09 and the fourth speed clutch C ₄ is pressure-engaged. At this time as well, the first speed clutch C ₁ is press-engaged, but as described above, the reduction ratio of the fourth speed is established by the action of the one-way clutch C ₀ . In this way, the automatic shift from the first speed to the fourth speed is performed.

The relationship between the speed reduction ratios of the first to fourth speeds and the solenoids 142 and 152 of the first and second solenoid valves 140 and 150 is shown in Table 1.

On the other hand, the hydraulic pump P discharged from the regulator valve Vr
A part of the operating oil pressure of the above flows into the torque converter T through the oil passage 334 provided with the throttle 368 to increase its internal pressure and is sent to the timing valve 210 and the on-off valve 230. The timing valve 210 is provided in the chambers 210A and 210B with the second speed clutch C ₂ and the fourth speed clutch C _{2 respectively} .
When the hydraulic pressure applied to the speed clutch C ₄ is introduced and the speed reduction ratio of the second speed or the fourth speed is established, the spool 211 moves to the left against the spring force of the spring 212 to move to the second speed. The spool 212 is moved to the right by the spring force of the spring 212 when the switching position is established, or when the reduction gear ratio of the first speed or the third speed is established, to take the illustrated first switching position.

The timing valve 210 connects the input oil passage 325 to the output oil passage 327 and the drain oil passage 321 of the modulator valve 220 to the drain EX regardless of which of these two switching positions.
However, during the transition to both switching positions, the output oil passage 327 is cut off from the input oil passage 325, and the drain oil passage 321 of the modulator valve 220 is cut off from the drain EX. The hydraulic pressure of the output oil passage 327 of the timing valve 210 is the modulator valve 220.
Is output to the output oil passage 353.
The modulator valve 220 modulates the operating oil pressure by the governor pressure P _G and the throttle pressure Pt to generate the engagement force of the direct coupling clutch Cd.The modulator valve 220 is provided in the chambers 220A and 220B via the oil passages 322 and 311 respectively, the governor pressure P _G and the throttle. Pressure Pt has been introduced,
With these two pressures and the spring force of the spring 222, the spool 221 is moved to the left side toward the valve opening side, and the feedback pressure of the output oil passage 326 is received by the left end surface of the spool 221 via the oil passage 326a and the throttle 372, and the governor pressure is received. It is configured to move the spool 221 to the right toward the valve closing side against P _G , the throttle pressure Pt, and the spring force of the spring 222. As a result, a pressure having a strength proportional to the vehicle speed U and the valve opening of the throttle valve appears in the output oil passage 353.

If the pressure output from this modulator valve 220 becomes too high, the modulator valve
The spool 221 of 220 moves to the right in the figure against the resultant force of the governor pressure P _G , the throttle pressure Pt and the spring 222, and drains the pressure to the drain EX via the timing valve 210. And
The drain oil passage 321 of the modulator valve 220 is inevitably connected to the drain EX via the timing valve 210 when not shifting, and the spool 211 of the timing valve 210 is in the middle of shifting.
Is moving, the drain oil passage 321 is cut off from the drain EX,
The pressure oil is not drained anywhere.

The reason for doing this is that it is necessary to control the engagement force (transmission capacity) of the direct coupling clutch Cd only by the third solenoid valve 240, and to prevent the engagement force of the direct coupling clutch Cd from being excessively reduced during shifting. Is. That is, during a gear shift, the line pressure Pl
Decreases and the throttle pressure Pt also drops momentarily. Therefore, if the spool 221 of the modulator valve 220 moves to the right in the figure and the drain oil passage 321 is connected to the drain EX at this time, the engagement force of the direct coupling clutch Cd also decreases. Therefore, at the time of gear shifting, the drain oil passage 321 of the modulator 220 is shut off from the drain EX in conjunction with the timing valve 210 to prevent pressure oil from escaping anywhere, so that the engagement force of the direct coupling clutch Cd at the time of gear shifting is reduced. Can be prevented.

The pressure in the output oil passage 353 of the modulator valve 220 is from the port 230a of the on-off valve 230 via the throttle 373, via the oil passage 326 and the cylinder 13 of the direct coupling clutch Cd in the torque converter T.
Be led to. Therefore, the engagement force (transmission capacity) of the direct coupling clutch Cd is strengthened according to the vehicle speed U and the valve opening degree of the throttle valve when the third solenoid valve 240 is closed. The on-off valve 230 receives the throttle pressure Pt in the chamber 230A via the oil passage 311, and the spool 231 resists the spring force of the spring 232 at the throttle pressure Pt to move to the left in the drawing to move the input oil passage 353. When the throttle valve opening is connected to the output oil passage 326 and there is no throttle pressure Pt, that is, when the throttle valve opening is in the idle position, the spool 231 is moved to the right by the spring force of the spring 232 and is held at the position shown in the drawing to drain the oil passage 326. It serves to connect to the EX and at the same time to connect the oil passage 325 and the oil passage 501. The on-off valve 230 releases the engagement of the direct coupling clutch Cd when the valve opening of the throttle valve is in the idle position. In this idle position, oil passage 325 and oil passage 501
And are connected, the amount of oil flowing into the torque converter T from the inlet port Ta of the torque converter T increases, the pressure in the torque converter T increases, and the piston 13
Is pressed to the left in the figure, the engagement of the direct coupling clutch Cd at the idle position (when the accelerator pedal is returned) can be reliably released.

The third solenoid valve 240 controls the engagement pressure of the clutch Cd by controlling the opening / closing between the oil passage 326 and the drain EX to control the operating pressure of the direct coupling clutch Cd or the pressure of the piston 13. Then, when the solenoid 242 of the third solenoid valve 240 is energized to open the valve, the hydraulic pressure of the oil passage 326 is reduced by the throttle 373, and the engagement force (transmission capacity) of the direct coupling clutch Cd is weakened.

The solenoid 242 of the third solenoid valve 240 measures the relative actual speed ratio e between the input and output members of the torque converter T by the electronic control unit 33, as described later, so that the speed ratio e is a reference range value. Controlled to enter inside. When the solenoid 242 of the third solenoid valve 240 is deenergized and the solenoid valve 240 is closed, the output of the modulator valve 220 itself becomes the engagement force of the direct coupling clutch Cd, and the output is the on-off valve 230. And acting on the hydraulic cylinder 13 via the oil passage 326, and the operating pressure is the vehicle speed U as shown by the solid line I in FIG.
Increases in proportion to. Note that, in FIG. 4, the influence of the throttle pressure Pt is omitted for simplification of the description, and the operating pressure curve shown by the solid line I shows that the valve opening of the throttle valve is at idle and the spring 222 is omitted. Time.

On the contrary, when the solenoid 242 of the third solenoid valve 240 is energized and the solenoid valve 240 is opened, the hydraulic cylinder 13 passes through the oil passage 326, the throttle 367 and the third solenoid valve 240. Directly connected clutch because the pressure drops when the drain EX is released
Cd engagement force is weak or zero, and its operating pressure is
The characteristics are indicated by the broken line IV in the figure. Therefore, the third solenoid valve 24
By controlling the duty ratio of the valve opening time of 0, the operating pressure of the direct coupling clutch Cd can be arbitrarily created between the solid line I and the broken line IV in FIG. In this embodiment, FIG. 4 and the solid line I
And the broken line IV are divided into 21 steps of "0 to 20" and the duty ratio is controlled.
In the figure, the operating pressure when the on-duty ratio (hereinafter simply referred to as the duty ratio) is 60% is shown by the solid line III and the duty ratio 3
The operating pressure at 0% is indicated by the solid line II, respectively. In FIG. 4, the straight line indicated by the chain line V is the internal pressure P _{T of the} torque converter _T.
The differential pressure between the working pressure indicated by the solid lines I to III or the broken line IV and the internal pressure P _T defines the strength of the engaging force of the direct coupling clutch Cd.

(Operation) FIGS. 5 to 7 are flowcharts showing the method of the present invention, and the operation of the method of the present invention will be described below with reference to the flowcharts. 5 to 7 are flowcharts showing the control procedure of the transmission capacity of the direct coupling mechanism according to the embodiment of the present invention, and the control procedure of the present embodiment will be described in detail below with reference to this flow chart. According to the control procedure of the present embodiment, a plurality of upper limit values and lower limit values are determined by the predetermined discriminant values e0-e4 (determined by the shift speed and the vehicle speed) of the gear ratio (rotational speed ratio) e of the torque converter T. Area (weak engagement area, reference value approximation area, reference value area, fine adjustment area,
The solenoid on region) is set in advance, the actual speed ratio e is compared with the upper limit value and the lower limit value of each region, and the valve opening time of the solenoid valve 240 is duty ratio controlled according to the comparison result.
Specifically, the duty ratio control variable value D that determines the on-duty ratio of the solenoid valve 240 is calculated depending on which region the actual speed ratio e is in and the like. This variable value D is
It is calculated by adding / subtracting a correction value x calculated depending on which of the regions the actual gear ratio e is in, whether the region where the speed ratio e is larger or smaller is shifted to the reference value region. With the on-duty ratio thus determined, the solenoid valve 240 is duty-ratio controlled for each timer time (timer period T) set according to each region, and the actual gear ratio e is converged to the reference value region.

In FIG. 5, first, when the ignition switch is turned on, the CPU of the electronic control unit 33 is initialized (step 1), and all variables related to the transmission capacity control of the direct coupling clutch Cd are set to initial values. Next, in step 2, the input data from the vehicle speed detector 31, the engine speed detector 34, the gear position detector 35, etc. is read, and the vehicle speed pulse signal and the engine speed pulse signal respectively input in step 3 are read. The vehicle speed U and the engine speed Ne are calculated by respectively measuring the time intervals of the torque converter T and the torque converter T (see FIG. 1 and FIG.
The gear ratio e between the pump impeller 2 and the turbine impeller 4 (see the figure) is calculated (step 4).

 This value e is calculated as follows.

When the turbine wheel speed is N ₂ , the speed ratio e of the torque converter T is expressed by the following equation.

On the other hand, since the torque converter output shaft 3 and the speedometer cable 30 are connected via the gear train, there is no slip between them and the reduction ratio between them is A and the speedometer cable 30 When the rotation speed is N ₃ , the rotation speed N ₂ of the torque converter output shaft 3 is N ₂ = A · N ₃ (2). When the equation (1) is organized by the equation (2), the speed ratio e is represented by the following equation.

Here, when the shift number of the auxiliary transmission M is four stages, A ₁ corresponding to the reduction ratio of the value of the reduction ratio A is the respective speeds detected, i.e. the first speed to fourth speed- It can take the value of A ₄ .

A rotation speed detector may be attached to the input shaft 3 of the auxiliary transmission M in order to obtain the output side rotation speed of the torque converter T.

After calculating the value e of the speed ratio in step 4, the process proceeds to step 5, and thereafter, the control (Cd, CONTROL) routine of the direct coupling clutch Cd shown in FIG. 6 is executed.

In FIG. 6, first, in step 1, the engine speed Ne
Is greater than a predetermined rotation speed Ne ₃ (for example, 3,500 rpm), and if the answer is affirmative (Yes), the process proceeds to step 16 to turn off the third solenoid valve 240, that is, close the valve directly. The operating oil pressure of the clutch Cd is increased and the engaging force of the direct coupling clutch Cd is strengthened. This means that if the engine speed Ne is 3,500 rpm or higher, problems such as vibration may not occur, and clutch slippage can be suppressed by increasing the engaging force of the direct coupling clutch Cd to improve the life and fuel efficiency of the direct coupling clutch Cd. Each can be achieved. The hydraulic pressure supplied to the direct coupling clutch Cd at this time is maintained on the solid line I in FIG.

If the answer to step 1 is negative (No), it is determined in step 2 whether or not the gear stage of the auxiliary transmission M is the fourth speed, and if the answer is affirmative (Yes), step 6 If it is negative (No), the routine proceeds to step 3, where it is determined whether or not the shift speed is the third speed. When the answer to step 3 is affirmative (Yes), that is, when the gear is the third speed, the process proceeds to step 5, and when the answer is negative (No), the process proceeds to step 4.

As a result of the determination in steps 2 and 3, the upper limit vehicle speed U ₃₂ becomes the predetermined vehicle speed U ₄₃₂ (for example, 85 km / h) in step 6 when the fourth speed, and the upper limit vehicle speed U ₃₂ becomes the designated vehicle speed in step 5 when the third speed. Second on U ₃₃₂ (eg 40km / h)
When the speed is lower than the maximum speed, the upper limit vehicle speed U ₃₂ is set to the specified vehicle speed U ₂₃₂ (for example, 30 km / h) in step 4. After setting the upper limit vehicle speed U ₃₂ to any one of the U ₂₃₂ , U ₃₃₂ , and U ₄₃₂ in this way, the process proceeds to step 7, and the vehicle speed U is set in any one of the steps 4 to 6. It is determined whether the vehicle speed is higher than the upper limit vehicle speed U ₃₂ , and if the answer is affirmative (Yes), problems such as vibration do not occur. Therefore, the process proceeds to step 16 and the third solenoid valve 240 is closed to directly connect. Increase the engaging force of the clutch Cd.

When the answer to step 7 is negative (No), that is, when the vehicle speed U is lower than the upper limit vehicle speed U ₃₂ , the process proceeds to step 8 and whether the vehicle speed U is higher than the lower limit vehicle speed U ₃₁ (for example, 6 km / h). To determine. The answer is negative (No), that is, the vehicle speed U is lower than the lower limit vehicle speed U ₃₁ , and the torque converter T
In the case of the low vehicle speed range requiring the torque amplification function of No. 3, the process proceeds to Step 18 and the third solenoid valve 240 is turned on, that is, the valve is opened to reduce the operating pressure of the direct coupling clutch Cd to reduce the operating pressure of the direct coupling clutch Cd. The engaging force of is reduced to utilize the function of the torque converter T. The operating hydraulic pressure supplied to the direct coupling clutch Cd at this time changes on the broken line IV in FIG. Step 8
If the answer is YES, that is, if the vehicle speed U is higher than the lower limit vehicle speed U ₃₁ , the process proceeds to step 9, and it is determined whether or not the gear stage of the auxiliary transmission M is the fourth speed. When the answer to this step 9 is affirmative (Yes), it is determined at step 10 whether or not the vehicle speed U is higher than a predetermined vehicle speed U ₃₆ (for example, 58 km / h), and when the answer is affirmative (Yes), that is, If the gear is the fourth speed and the vehicle speed U is higher than the predetermined vehicle speed U ₃₆ , in step 12, the discriminant values e ₁ (for example 92%), e ₂ (for example 97%) in the predetermined speed ratio range,
Set e ₃ (eg 99.5%) and e ₄ (eg 102%) respectively. The discriminant value e ₁ is an upper limit value of a region where the engagement force of the direct coupling clutch Cd is weak (hereinafter referred to as an engagement force weak region) and at the same time is a lower limit value of a region approximated to the reference value (hereinafter referred to as a reference value approximation region). The discriminant value e ₂ is the upper limit value of the reference value approximation region and the lower limit value of the reference value region (target region) at the same time. Discriminant value e ₃
Is the upper limit of the reference value region and at the same time the lower limit of the fine adjustment region. The discriminant value e ₄ is the upper limit value of the fine adjustment region and at the same time is the lower limit value of the region in which the solenoid is turned on to open the third solenoid valve 240 (hereinafter referred to as the solenoid on region). When the answer to step 10 is negative (No), that is, when the speed is the fourth speed and the vehicle speed U is lower than the predetermined vehicle speed U ₃₆ , the determination value e ₁ (for example, 88%), e ₂ is determined in step 13.
(Eg 94%), e ₃ (eg 97.5%), e ₄ (eg 99)
%) Respectively. That is, in step 10, the region of the fourth speed which is the high speed stage is divided into two regions of steps 12 and 13 with the predetermined vehicle speed U ₃₆ as a boundary, and when the predetermined vehicle speed U ₃₆ or more, the larger one set in step 12 is set. Using the discriminant values e _{1 to} e ₄ (larger than the discriminant values e _{1 to} e ₄ set in step 13) of the pump impeller 2 and the turbine impeller 4 in a predetermined reference range. Value (target area of slip ratio)
Even if the vehicle speed is increased, there is no risk of vehicle vibration in the high vehicle speed range, and fuel economy can be expected to improve.If the vehicle speed is less than the predetermined vehicle speed U _36, the smaller discriminant values e _{1 to} e ₄ set in step 13 are used. By lowering the predetermined reference range value, the power performance can be expected to be improved, and the discriminant values set in steps 12 and 13 are selectively used according to the purpose of priority of fuel consumption or power performance.

If the answer to step 9 is negative (No), that is, if the gear is not the fourth speed, the process proceeds to step 11 to determine whether the gear is the third speed. This step
If the answer to 11 is affirmative (Yes), that is, if it is the third speed, in step 14, the discriminant values e ₁ (eg 88%), e ₂ (eg 94%), e ₃ (eg 97.5%), e Set ₄ (eg 99%) respectively.

If the answer to step 11 is negative (No), that is, if the gear stage is neither the fourth speed nor the third speed, the process proceeds to step 15, and the determination value e ₁ (for example, 88%), e ₂ (For example
94%), e ₃ (e.g. 97.5%), e ₄ (e.g. 99%) respectively set.

If the vehicle speed is different, the predetermined reference value area (e2, e3) of the discriminant value in the optimum speed ratio range is different, but according to the above-mentioned embodiment, the width and the setting position of the predetermined reference range value can be freely set to the optimum values. Therefore, it is possible to improve fuel efficiency and power transmission characteristics according to the vehicle speed. That is, when the gear position of the auxiliary transmission M is the fourth speed and is equal to or higher than the predetermined vehicle speed U36 (58 km / h), even if the predetermined reference range value is increased, there is no possibility that the vehicle body vibration occurs in the high vehicle speed region, and the fuel consumption is reduced. Improvement can be expected, and when the shift speed is the fourth speed and is equal to or lower than the predetermined vehicle speed U36, it is possible to expect improvement in power performance by lowering the predetermined reference range value using the smaller discriminant value. Step S12 and step S of FIG. 6 according to the purpose of priority
By properly using the discriminant value set in 13, it is possible to improve fuel consumption and power transmission characteristics according to the vehicle speed.

After setting the respective discriminant values e _{1 to} e ₄ in steps 12 to 15, the process proceeds to step 17, and the solenoid valve 240 shown in FIG.
Execute the duty ratio control (solenoid valve DUTY CONTROL) routine of.

In steps 1, 2, 3, and 7 in FIG. 7, it is determined which region of the speed ratio range the current speed ratio e is in. First, considering that the speed ratio e changes from the lower side to the upper side, if the speed ratio e is in the engagement force weak region, it is determined whether or not the speed ratio e in step 7 is larger than the determination value e _1. Is negative (No), the timer period
It is determined whether T ₁ has passed (T = 0).

FIG. 8 shows the duty ratio control state when the speed ratio e passes from the weak engagement force region to the upper reference value approximation region and enters the upper reference value region. As the speed ratio e approaches the reference value region, the increasing speed of the transmission capacity of the direct coupling clutch Cd is decreased, that is, the change rate of the transmission capacity is controlled to be smaller.

When the speed ratio e is in the engagement force weak region, T ₁ (for example, 0.
Each time a period of 2 seconds) elapses, the engagement force of the direct coupling clutch Cd is controlled by controlling the duty ratio of the opening time of the third solenoid valve 240 with a smaller duty value for x ₁ (correction value, eg, 1). Gradually strengthen. In FIG. 7, when the answer to step 8 is affirmative (Yes), that is, when the timer period (T ₁ ) has elapsed (t ₁ , t ₂ , and t _{3 in} FIG. 8), step 9 is renewed each time. In step 10, the value T ₁ is set in the timer, and in step 10, the variable value D is set to a value (D−x ₁ ) which is smaller than the previous value by x ₁ and stored, and the duty at the stage indicated by the D value is set. The duty ratio control of the valve opening time of the third solenoid valve 240 again for the period T ₁ (steps 8 to 1).
Repeat 3). Note that step 11 is a limit check, and if the variable value D becomes smaller than 0, inconvenience will occur in program control. Therefore, it is judged whether or not the variable value D is larger than the minimum D ₁ lim (for example, 0). Answer is negative (N
In the case of o), that is, when the variable value D is smaller than 0, the value of the variable value D is set to the minimum value D ₁ lim in step 12, and the process proceeds to step 13. If the answer to step 11 is affirmative (Yes), that is, if the variable value D is greater than 0, step 12
And jump to step 13.

In step 13, the value of the variable D set in step 10 is stored as a variable D ₃₂ for later use in control such as when the speed ratio e enters the reference value region. After this,
In step 14, a counter for controlling the energization time of the solenoid 242 of the third solenoid valve 240 is set to a value corresponding to the variable value D, and thereafter, the process returns to step 2 in FIG. 5 and is executed again. The electronic control unit 33 repeats the opening of the third solenoid valve 240 at the same duty ratio, that is, at a constant cycle until the duty ratio of the third solenoid valve 240 is set to a new value. Here, the duty ratio of the third solenoid valve 240 is intended to refer to the ratio of the energization time of the solenoid 242 for a predetermined time (e.g. 100 ms), one step per When set to 21 stages of + D ₀ to D ₂₀ The energization time is 5 ms.

In this way, when the gear ratio e is in the engagement force weak region, the engagement force of the direct coupling clutch Cd is gradually increased to x ₁ every T ₁ period.

Next, when the speed ratio e enters the reference value approximate area, it is determined whether or not elapsed timer period if the answer to the question of the step 7 (t ₄ time of Figure 8) is affirmative (Yes), and the step 15. The timer period here is the value T ₁ set when the speed ratio e is in the weak engagement region immediately before entering the reference value approximation region, that is, at the time point t ₃ in FIG. If the answer to step 15 is negative (No), that is, while the timer period T ₁ has not elapsed, steps 13 and 14 are executed without executing steps 16 to 19, and the duty ratio set in the engagement force weak region is set. Subsequently, the opening control of the third solenoid valve 240 is performed. The answer to step 15 is positive (Y
es), that is, when the timer period T ₁ has elapsed (at time t _{5 in} FIG. 8), a predetermined value T ₂ (for example, 1) which is larger than the T ₁ value set in the timer in the engagement weak region in step 16 is used. Second) is set, and in step 17, the variable value D is set to a value (D−x ₂ ) which is smaller than the previous value by x ₂ (for example, 1) and stored, and the duty ratio at the stage indicated by the D value is set. Then, the duty ratio control of the valve opening time of the third solenoid valve 240 is performed again for the T ₂ period. Then, when the timer period T ₂ has passed again and the value of the gear ratio e is still within the reference approximation region (at the time of t ₆ in FIG. 8), steps 15 to 19 and 13 are repeatedly executed as described above. . Note that step 18 is the same limit check as step 11, and it is determined whether or not the variable value D is larger than the minimum value D ₂ lim (for example, 0), and the answer is negative (No).
If the variable value D is smaller than 0,
In step 19, the value of the variable D is set to the minimum value D ₂ lim, and the process proceeds to step 13.

If the answer to step 18 is affirmative (Yes), that is, if the variable value D is greater than 0, step 13 is performed without executing step 19.

When the speed ratio e enters the reference value region at time t _{7 in} FIG. 8, the answer of the determination in step 3 as to whether the speed ratio e is larger than the determination value e ₂ is affirmative (Yes), and in step 20. The flag F ₁ to be described later is set to 0, and the routine proceeds to step 21, where it is also determined whether or not 1 is set to the flag F ₃ to be described later.
When the speed ratio e enters the reference value region from a smaller value, both flags F ₂ and F ₃ are set to 0 (steps 5 and 6), and the answer to step 21 is negative (No), The answer to the determination in the next step 24 as to whether the flag F ₂ is set to 1 is also negative (No), and in this case, the process proceeds to step 26 to determine whether or not the timer period has elapsed.
The timer period here is the value T ₂ set when the speed ratio e is in the reference value approximation region, that is, at time t ₆ in FIG. If the answer to step 26 is negative (No), that is, if the timer period T ₂ has not elapsed, steps 27 to 28 are not executed, and steps 14 to 46 described later are executed and step 14 is executed to set in the reference value approximation region. The third solenoid valve 240 is continuously controlled to open with the duty ratio thus set. The answer to step 25 is positive (Y
es), that is, when the timer period T _{2 has} elapsed (eighth
At time t _{8 in the} figure), at step 27, a new value is given to the timer when the speed ratio e is in the reference value region, that is, T ₃ (for example, 2
(Second) is set, and when the value stored as the variable value D ₃₂ in step 13 in the previous loop is set in step 28, that is, when the speed ratio e is in the reference value approximation region immediately before entering the reference value region ( the t ₆ time) value set in Figure 8 to set it. When the speed ratio e enters the reference value region in this way, the timer period T ₃ is set using the value set immediately before entering the reference value region (time t _{6 in} FIG. 8) without rewriting the value of the variable D. until passage (t ₉ when the Figure 8) a third solenoid valve
Duty control the valve opening time of 240. Direct coupling clutch Cd as long as speed ratio e is within the reference value range after t ₉
Control so as not to change the transmission capacity of.

FIG. 9 shows a duty ratio control state by a method different from that in FIG. 8 in the duty ratio control when the speed ratio e enters the reference value region from the engagement force weak region through the reference value approximation region similarly to FIG. . That is, in the case of FIG. 8, by making the values of x ₁ and x ₂ the same and making the values of T ₁ , T ₂ and T ₃ different, the speed ratio e approaches the reference value region and the speed ratio e The time change rate of
In the case of the figure, the values of T ₁ , T ₂ and T ₃ are all the same and x
_By making the values of ₁ and x ₂ different, the time change rate of the speed ratio e becomes smaller as the speed ratio e approaches the reference value region.

FIG. 10 shows the duty ratio control state when the speed ratio e exceeds the reference value region, enters the fine adjustment region above the reference value region, and returns to the reference value region again without exceeding the fine adjustment region. Indicates. In this case, if the speed ratio e enters the reference value region from the lower side, the values of all the flags of F ₁ , F ₂ and F ₃ are 0. Therefore, the speed ratio e is
When it rises from the time point t _{10 in} (a) of FIG. ₁₀ and exceeds the reference value area at the time point t ₁₁ to enter the fine adjustment area immediately above the reference value area, the speed ratio e in step 2 of FIG. answer of the determination of ₃ whether greater than affirmative (Yes) and the process goes to step 30 after setting to 1 a flag F ₁ proceeds to step 29. The step 30 decides whether or not the flag F ₂ is 0, but since the flag F ₂ is still set to 0, the answer to the decision is affirmative (Yes), and the routine moves to step 31. And set the flag F ₂ to 1. Then step 32
Then, the value of the variable D ₃₂ is stored as the variable value D ₃₃ . This D ₃₂
The value is the same as the D value used when the speed ratio e is within the reference value region, that is, the D value set in step 28.
In addition, FIG. 10 shows changes with time of the respective values of the variables D, D ₃₂ and D ₃₃ together with the change of the speed ratio e. In this case, each value of the variable D and the like is shown only by the increase / decrease value with the value set when the speed ratio e value is in the reference value region as a reference. Next, in step 33, the timer is set to a predetermined value T ₄ (for example, 0.4 seconds), and in step 34, the variable value D used for the current control is set, and x ₆ (for example, 6) is added to D ₃₃ used for the previous control. After setting the value, the process returns to step 2 of FIG. 5 and re-executes through steps 41 to 46 and 14 described later.

It should be noted here that when the speed ratio e is in the reference value region immediately before entering the fine adjustment region, that is, the timer period T ₃ set at the time t _{10 in} (a) of FIG. t _'11
Although it does not time up until the time point, at time t ₁₁ when the speed ratio e reaches the judgment value e ₃ , that is, the lower limit value of the fine adjustment area, the timer is immediately reset to the value T ₄ (step 3
3) The control is repeated with the value of D set in step 34 until the T ₄ period elapses. When such a repetition is reached to step 30, in the previous loop, the flag F _{2 is set} to 1 in step 31.
Since the answer to step 30 is negative (No), the process moves to step 35. Since the timer period T ₄ has not yet expired, it is determined whether the timer period in step 35 has elapsed. The answer is negative (No) and the step
At 36, set the variable value D ₃₂ to the D ₃₃ value set in step 32 above.
A value obtained by adding x ₃ (for example, 1) is stored. Since the value D ₃₂ was set as the variable value D ₃₃ in step 32 in the previous loop, and the value set when the speed ratio e is in the reference value area is D ₀ , the value newly stored as the D ₃₂ value is Value D ₀ to x
Equal to the value obtained by adding ₃ .

Before the speed ratio e elapses the timer period T ₄ , that is,
If it returns to the reference value region again at time t ₁₂ , the answer in step 3 becomes affirmative (Yes), the process moves to step 20 to set the flag F ₁ to 0, and the next step 21 is the flag F in this case. _{Since 3} is still set to 0, go past step 24. Since the flag F ₂ is set to 1 in step 31, the answer to step 24 is affirmative (Yes), the process moves to step 25 to set the flag F ₂ to 0, skips step 26 and moves to step 27, and sets the timer. The predetermined value T ₃ is set. That is, jumping from step 26 to step 27 means resetting the timer immediately after the speed ratio e returns to the reference value region.

Next, at step 28, the value D ₃₂ stored at step 36 in the previous loop is set to the variable value D, and the duty ratio control of the opening time of the third solenoid valve 240 is performed at the duty ratio at the stage indicated by the D ₃₂ value.

Then, even at the time point t ₁₃ when the speed ratio e elapses the timer period T _3, as long as it is within the reference value range, the timer is turned on again.
The T ₃ value is set (step 27) and the D value is not changed, and the duty ratio is controlled at the same value D ₃₂ (step 28) after the time point t ₁₄ .

For the 10 view of (a) a case containing short (shorter period of time than the timer period T ₄₎ in the fine control area exceeds the reference value region is the speed ratio e. That is, since the speed ratio e has entered the fine adjustment range, the value is corrected to a large value of x ₆ at time t _{11, and} as a result, the time immediately returns to the reference value range at time t ₁₂ when the timer period T ₄ does not elapse. That is, the x ₆ value is too large, and therefore, at the time t ₁₂ when returning to the reference value region, in the reference value region immediately before exceeding the reference value region, that is, t ₁₀
The duty ratio is controlled by using the value obtained by adding a small correction value x ₃ to the variable D value set at the time
Is held in the reference value area.

For the FIG. 10 (b), by correcting a large value of the value x ₆ at t ₁₆ by the speed ratio e enters the fine control area greater than the reference value region up from t ₁₅ time However, it does not return to the reference value area immediately and becomes longer in the fine adjustment area (timer period
The time is longer than T ₄ ). Immediately before this enters the fine control area exceeds the reference value region, i.e., a value obtained by adding the x ₆ values in D value set at t ₁₅ when the speed ratio e value is greeted fine control area The speed ratio e is held in the reference value region by controlling the duty ratio using a value obtained by adding a value according to the time length.

Therefore, in the case of the tenth view of (b), the at t ₁₆ time 1
As in the case of time t _{11 in} (a) of FIG.
There are respectively executed, from t ₁₆ time until t reaches ₁₇ times,
The steps 29, 30, 35 and 36 are executed respectively. And
When the time point t ₁₇ is reached, the timer period T ₄ is first timed up, the answer in step 35 is affirmative (Yes), the process moves to step 37, and the flag F ₃ is set to 1, and then step The value D used in the previous loop is stored in D ₃₃ as a variable value in 38. Then, in step 39, the T ₄ value is set again in the timer, and in step 40, the value obtained by adding the value x ₃ (for example, 1) to the D value is set. Then, at time t ₁₈ , step 2 is repeated until the timer period T ₄ further expires.
9, 30, 35 and 36 are executed respectively, and in step 36, the value obtained by adding the value x ₃ to the value D ₃₃ is stored as the value D ₃₂ . If the speed ratio e is still in the fine adjustment area at the time point t ₁₈ , steps 37 and 38 are executed respectively as described above. The fact that steps 37 and 38 are executed means that the D ₃₃ value is updated to a value obtained by adding the value x ₃ , and the value x ₃ is further added to the D value in step 40, so that the duty cycle is re-executed. The value increases, and the duty ratio control is repeated at this value. Then, when the speed ratio e returns to the reference value region at time t ₁₉ , steps 20 and 21 are executed. The answer to step 21 is that the flag F _{3 in} step 37
Since 1 was set to 1, it becomes affirmative (Yes), and step 22
Then, the flag F _{3 is set} to 0, the flag F _{2 is set} to 0 in step 23, the step 24 is skipped, the process proceeds to step 26, and it is determined whether or not the timer period T ₄ is up. Jumping over step 24, that is, not determining the flag F ₂ means that the changing state of the speed ratio e is gradual. When the speed ratio e changes gently, the duty value set in the previous loop is used as it is. That is, until the timer period T ₄ elapses, that is, t ′ ₁₉
Wait until the point in time and perform duty control using the duty value set in the previous loop as it is. And t '
_{When the} time reaches ₁₉ , the answer in step 26 becomes affirmative (Yes), and in step 27 the timer is set to the T ₃ value,
At 28, the value D ₃₂ is set to the variable value D. This D ₃₂ value is the step
This is the value set immediately before exiting the fine adjustment area set in 36.

In this way, when the speed ratio e returns to the reference value region, the duty ratio control is continuously performed by the variable value D, and the speed ratio e
As long as is within the reference value range, the duty ratio is controlled by holding the value even after time t ₂₀ .

FIG. 11 shows the control state when the speed ratio e exceeds the fine adjustment region from the reference value region, enters the solenoid on region, and then returns to the reference value region again.

Note that FIG. 11 shows a range in which the speed ratio e is larger than the discriminant value e ₄ , that is, a state in which the solenoid is on.

FIG. 11 (a) shows the case where the speed ratio e passes through the fine adjustment area within a short time and enters the area where the solenoid is turned on.
FIG. 11B shows the case where the speed ratio e passes through the fine adjustment region for a long time and enters the region where the solenoid is turned on. In both cases (a) and (b) of FIG. 11, since the speed ratio e approaches the upper limit value 1.0 (en), there is a risk of occurrence of vehicle body vibration. Therefore, the maximum duty ratio is D ₂₀ (see FIG. 3). The solenoid 242 of the solenoid valve 240 is turned on to open the solenoid valve 240), but the duty value when the speed ratio e returns from the solenoid on region to the fine adjustment region is 11th.
The value in (a) of the figure is set to a value larger than that in (b).

That is, in FIG. 11A, when the speed ratio e rises from time t ₂₉ and enters the fine adjustment region at time t ₃₀ , first,
The answer to step 2 in the figure is affirmative (Yes), and steps 29 to 34 are executed in the same manner as described with reference to FIG. At this time, the D value and the D ₃₃ value are respectively + x ₆ (for example, 4) with respect to the previous value,
± 0.

Then, in the next loop, steps 29, 30, 35 and 36 are executed respectively, and the value obtained by adding the value x ₃ (for example, 1) to the value D ₃₃ is stored as the value D _{32 in} step 36. At this time, the flag F ₃ remains 0. In this state, if the speed ratio e exceeds the fine adjustment region before the timer period T ₄ elapses (at time t ₃₁ ), it is determined whether or not the speed ratio e in step 1 of FIG. 7 is larger than the determination value e _4. Answer to yes, step 47
Then, the flag F ₂ is set to 1, and it is determined in step 48 whether the flag F ₃ is set to 1. As mentioned above, the flag F ₃ remains 0 and the speed ratio e exits the fine adjustment area and enters the solenoid on area, so the answer to step 48 is negative (No), and the process moves to step 50 to set the D ₃₃ value. Value x
_The value obtained by adding ₅ (for example, 6) is stored as the D value. Next, at step 51, it is judged (limit check) whether or not the D value is larger than the D _F o value (= 20). The answer is positive (Ye
If s) proceeds to set the D value to the value D _F o at step 52 to step 53, and proceeds to step 53 skips step 52 If negative (No). In step 53, the D value (for example +6) set in step 51 is stored as a D ₃₂ value, the timer is set to 0 in step 54, and the third solenoid valve is set in step 55.
While the solenoid 242 of 240 is turned on to keep the solenoid valve 240 in the open state, in step 56, the valve opening duty ratio control of the third solenoid valve 240 by the electronic control unit 33 is stopped, and the solenoid valve 240 of FIG. Return to step 2.

When the speed ratio e enters the fine adjustment area again at time t _{32 in} (a) of FIG. 11, the answer to step 2 in FIG. 7 becomes affirmative (Yes) and 1 is set in the flag F ₁ in step 29. Then
The answer to step 30 is flag F _{2 in} step 47 of the previous loop.
Since 1 has been set to 1, the result is negative (No), and the process proceeds to step 35. The answer to step 35 is affirmative (Yes) because the timer was set to 0 in step 54 of the previous loop, the flag F ₃ is set to 1 in step 37, and the D value (+ x _{5 in} step 38). , +6) is stored as the D ₃₃ value. Then, in step 39, the predetermined value T ₄ is set in the timer, and in step 40, the value of D + x ₃ (that is, + 6 + 1 = + 7) is changed to the new D.
The value of D ₃₃ + x ₃ (that is, + 6 + 1 = + 7) is stored as a D ₃₂ value in step 36 of the next loop.

Thereafter, at t ₃₃ the time from the speed ratio e is in following the fine adjustment region, a step 29,30,35,37～40 each run. In step 38, the D value (+7) is stored as the D ₃₃ value, and in step 40, the value of D + x ₃ (+8) is stored as the D value. Then, the answer to step 35 becomes negative (No) again, and the process proceeds to step 36, and the value of D ₃₃ + x ₃ (+8) is stored as the value of D ₃₂ . Next, 'when the speed ratio e at ₃₃ point enters the reference value region, t ₁₉ ~t of FIG. 10 described above (b)' t reaches the ₁₉ time and are controlled by the same action t ₃₄ time After that, as long as the speed ratio e is within the reference value region, the duty ratio is controlled without changing the D value.

For the FIG. 11 (b), respectively when the speed ratio e at t ₃₅ the time to enter the fine control area QF, the Fig. 11 steps 29-34 of Figure 7 similarly to the t ₃₀ time points (a) s Run and in step 32
The value (+4) of D ₃₃ + x ₆ is stored in D ₃₂ , that is, ± 0, as a D value in step 34, and D ₃₃ + x ₃ is stored in step 36 of the next loop.
Store (+1) as the D ₃₂ value. At time t ₃₆ after the lapse of T ₄ period, the speed ratio e is still in the fine adjustment region, so steps 29, 30, 35 and 37 are executed respectively, and at the next step 38 D
The value (+4) is stored as the D ₃₃ value, steps 39 and 40 are executed, and the value of D + x ₃ (+5) is stored as the D value in step 40.

When the speed ratio e exits the fine adjustment area and enters the solenoid on area at time t ₃₇ , the answer to step 1 in FIG. 7 becomes affirmative (Yes), and steps 47 and 48 are executed respectively.
In this case, since the speed ratio e was in the fine adjustment area from the time t ₃₅ until the first time T ₄ period elapsed and time t _{37 in} the middle of the next T ₄ period, the change state of the speed ratio e is It is moderate, and flag F ₃ is set to 1. Therefore, the answer of the step 48 becomes affirmative (Yes), the process moves to a step 49, the value of D ₃₃ + x ₄ , that is, +5 is set as the D value, and then the step 52 is executed and the answer is affirmative (Yes). If so, the process proceeds to step 53, and if negative (No), the process skips step 52 and proceeds to step 53. Step in step 53
The D value set in 49, that is, +5, is stored as the D ₃₂ value, and thereafter, steps 53 to 56 are executed, respectively, and the process returns to step 2 in FIG. 5 and is executed again.

Then, when the speed ratio e enters the fine adjustment region again at time t ₃₈ , steps 29, 30, 35 and 37 are executed respectively, and the next step
At 38, the D value (D ₃₃ + x ₄ = + 5) is stored as the D ₃₃ value. Next, in step 40, the value D ₃₃ + x ₃ = + 6 is set to the value D _32.
Store as a value.

Thereafter, when the speed ratio e at t ₃₉ the time has not yet elapsed period T ₄ enters the reference value region, t ₁₂ ~t ₁₃ similar controlled and t ₄₀ time at the working and the time point of FIG. 10 described above (a) reaches the t ₄₁ time through, since, as long as the speed ratio e is within the reference value region, D
The duty ratio is controlled without changing the value of.

In step 4 in FIG. 7, F ₁ = 1 means that the speed ratio e once enters the fine adjustment region from the reference value region, and the speed ratio e in the next loop passes over the reference value region and when it reaches the engagement force weak regions, i.e., when the speed ratio e is changed abruptly, that it performed control in D value set in the fine adjustment region of the previous from 1 to flag F ₁ is set is there. In addition, steps 41 to 46 are D, D
_If each value of ₃₂ and D ₃₃ is greater than the D _F o value (eg 20),
Each of these values is rewritten into the value D _F o.

In the above embodiment, the case where the fluid type torque converter T is adopted as the fluid type power transmission device has been described, but the present invention can be applied to other vehicle automatic transmissions including fluid couplings of other types. Is.

Further, the predetermined parameter representing the relative slip amount of the input / output member of the fluid type power transmission device may be the difference between the rotational speeds of the input / output member.

(Effects of the Invention) As described in detail above, according to the method for controlling the direct coupling mechanism of the hydraulic power transmission device for an automatic transmission for a vehicle of the present invention, the relative slip amounts of the input and output members of the hydraulic power transmission device can be determined. The transmission capacity of the direct coupling mechanism that mechanically engages the input and output members is set so that the predetermined parameter value (e) represented is within a reference value range having preset upper and lower limits. In a direct coupling mechanism control method for a fluid type power transmission device of an automatic transmission for a vehicle that is variably controlled, a vehicle speed (U) is detected, and an upper limit value and a lower limit value of the reference value region are detected according to the detected vehicle speed. By setting, the transmission capacity of the direct coupling mechanism is controlled according to the vehicle speed. Therefore, for example, the higher the vehicle speed, the stronger the engaging force of the direct coupling mechanism and the better the fuel consumption and power transmission characteristics. That is, if the vehicle speed is different, the optimum slip amount is different.Therefore, the target regions of the slip amount should be set to different values.However, according to the control method of the present invention, the upper limit value and the lower limit value of the reference value region are set to the vehicle speed. Since it can be set to the optimum value corresponding to, it is possible to improve fuel economy and power transmission characteristics (prevent cruising) regardless of the vehicle speed. In particular, since the target value of the relative slip amount of the input and output members is set according to the vehicle speed related to the rotation speed of the output side of the input side of the fluid torque converter, the change in the engine rotation speed is It is absorbed to some extent, and there is no large change in the target value (generally, the change in vehicle speed is small compared to the change in engine speed), and the effect of stabilizing the control is also obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an automatic transmission for a vehicle to which the direct connection mechanism control method of the present invention is applied, FIG. 2 is a hydraulic control circuit diagram of the automatic transmission for the vehicle, and FIG. FIG. 4 is a main part developed view, FIG. 4 is a graph showing the relationship between the hydraulic pressure of the direct coupling clutch and the vehicle speed, FIG. 7 is a sub-flowchart showing the control procedure performed in step 5 of the figure, FIG. 7 is a sub-flowchart showing the control procedure performed in step 17 of FIG. 6, and FIG. 8 shows the timer period with the same duty ratio correction value. FIG. 9 is a graph showing the relationship between the speed ratio and the duty ratio in the control when the speed ratio enters the reference value region from the weak engagement force region through the reference value approximation region. , Timer period The speed ratio and the duty ratio in the control when the speed ratio enters the reference value region from the weak engagement region through the reference value approximation region, FIG. 10 shows the speed ratio as the reference value region. 11 is a graph showing the relationship between the speed ratio and the duty ratio in the control in the case of entering the fine adjustment region above the reference value region and returning to the reference value region again without exceeding the fine adjustment region, FIG. 7 is a graph showing the relationship between the speed ratio and the duty ratio in the control when the speed ratio exceeds the fine adjustment region from the reference value region to enter the region for turning on the solenoid and then returns to the reference value region again. T ... Torque converter (fluid type power transmission device), 2 ...
… Pump impeller (input member), 4 ... Turbine impeller (output member), Cd… Direct coupling clutch (direct coupling mechanism).

Front page continued (72) Inventor Yoshimi Sakurai 1-4-1 Chuo, Wako-shi, Honda R & D Co., Ltd. (72) Inventor Yukihiro Fukuda 1-4-1 Chuo, Wako-shi, Honda R & D Co., Ltd. (56) References JP-A-57-33253 (JP, A) JP-A-57-157831 (JP, A) JP-A-60-192163 (JP, A)

Claims (4)

(57) [Claims] 1. A predetermined parameter value (e) representing a relative slip amount of the input and output members of a fluid type power transmission device having an input member and an output member has an upper limit value and a lower limit value set in advance. In the direct coupling mechanism control method of the fluid type power transmission device of the automatic transmission for a vehicle, which variably controls the transmission capacity of the direct coupling mechanism that mechanically engages the input and output members so that the value is within the reference value range, A direct connection of a fluid power transmission device for an automatic transmission for a vehicle, which detects a speed (U) of a vehicle and sets an upper limit value and a lower limit value of the reference value region according to the detected vehicle speed. Mechanism control method. 2. The higher the vehicle speed (U), the at least one of the upper limit value and the lower limit value of the reference value region is determined to be a value with a smaller relative slip amount of the input / output member. A method for controlling a direct coupling mechanism of a hydraulic power transmission device for an automatic transmission for a vehicle according to claim 1. 3. The hydraulic power transmission for an automatic transmission for a vehicle according to claim 1, wherein the predetermined parameter value is a ratio of respective rotational speeds of the input member and the output member. Direct connection mechanism control method for equipment. 4. The fluid power transmission of an automatic transmission for a vehicle according to claim 1, wherein the predetermined parameter value is a difference between respective rotational speeds of the input member and the output member. Direct connection mechanism control method for equipment.