JPS627428B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a torque converter direct coupling clutch control device for an automatic transmission comprising a torque converter with a direct coupling clutch and a planetary gear transmission mechanism having a low speed hydraulic servo and a high speed hydraulic servo. <Prior art> Conventionally, in a torque converter with a direct coupling clutch for an automatic transmission for an automobile, the torque converter is directly coupled at two or more gears during high-speed operation to prevent power loss due to the torque converter, and
When changing gears, the direct coupling clutch is temporarily released to prevent impact caused by the gear change. <Problems to be Solved by the Invention> However, in this conventional device, the direct coupling clutch is controlled by hydraulic pressure, which complicates the control device and increases the size of the hydraulic control device, impairing its mountability on a vehicle. There was a problem. In addition, since the direct coupling clutch is controlled using a spool valve controlled by hydraulic pressure, the spool valve may become stuck due to chips in the hydraulic control device, preventing the direct coupling clutch from releasing during gear shifting. There was a risk that an excessive shift shock would occur, or that the direct coupling clutch would not release when the vehicle stopped and the engine would stop. The present invention solves these conventional drawbacks and provides a compact and highly reliable torque converter direct-coupled clutch control system for an automatic transmission. <Means for Solving the Problems> The present invention provides an automatic transmission equipped with a torque converter with a direct coupling clutch and a planetary gear transmission mechanism having a low-speed hydraulic servo and a high-speed hydraulic servo, for engaging the direct coupling clutch. an oil passage to which a signal hydraulic pressure is supplied; a lock-up shift valve connected to the oil passage for switching engagement and release of a direct coupling clutch according to the signal oil pressure in the oil passage; and a lock-up shift valve for discharging the oil pressure in the oil passage. a solenoid valve provided to
A switch that operates when the oil pressure in the high-speed hydraulic servo exceeds a predetermined value, and a solenoid valve that discharges the oil pressure in the oil passage for a predetermined period of time when the switch is switched from OFF to ON or from ON to OFF. The present invention is characterized in that it is equipped with an electric circuit for controlling the clutch, and is configured to release the direct coupling clutch for a predetermined period of time when shifting between low speed and high speed. <Effects of the Invention> According to the present invention, a solenoid valve for discharging and controlling the hydraulic pressure in the oil passage is provided in the oil passage to which the signal oil pressure for engaging the direct coupling clutch is supplied, and the speed change between low speed and high speed is achieved. Since the solenoid valve is operated for a predetermined period of time to temporarily release the direct coupling clutch, the control device for temporarily releasing the direct coupling clutch during gear shifting can be compactly constructed. In addition, a switch that operates when the hydraulic pressure in the high-speed hydraulic servo exceeds a predetermined value, and a solenoid that operates to discharge the hydraulic pressure in the oil passage for a predetermined period of time when the switch is switched from OFF to ON or from ON to OFF. An electric circuit is provided to control the valve, and a solenoid valve is used to release the direct coupling clutch for a predetermined period of time between low and high speeds. This prevents excessive shift shocks caused by valve stays or when the vehicle is stopped. The engine will no longer stall due to the direct coupling clutch not releasing.
This has the effect of improving the reliability of direct clutch control. <Example> The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing an example of a hydraulic automatic transmission with an overdrive device. This automatic transmission includes a torque converter 1 with a direct coupling clutch, an overdrive mechanism 2, and a gear transmission mechanism 3 with three forward speeds and one reverse speed. The pump 5 is connected to an engine crankshaft 8, and the turbine 6 is connected to a turbine shaft 9. The turbine shaft 9 constitutes the output shaft of the torque converter 1, which also serves as the input shaft of the overdrive mechanism 2, and is connected to a carrier 10 of a planetary gear system in the overdrive mechanism. Further, a direct coupling clutch 50 is provided between the engine crankshaft 8 and the turbine shaft 9, and mechanically couples the engine crankshaft 8 and the turbine shaft 9 when the direct coupling clutch 50 is operated. Planetary pinion 14 rotatably supported by carrier 10
meshes with sun gear 11 and ring gear 15. A multi-plate clutch 12 and a one-way clutch 13 are provided between the sun gear 11 and the carrier 10, and a housing or overdrive case 16 containing the sun gear 11 and the overdrive mechanism is provided.
A multi-plate brake 19 is provided between them. The ring gear 15 of the overdrive mechanism 2 is connected to the input shaft 23 of the gear transmission mechanism 3. A multi-plate clutch 24 is provided between the input shaft 23 and the intermediate shaft 29, and a multi-disc clutch 24 is provided between the input shaft 23 and the sun gear shaft 3.
A multi-plate clutch 25 is provided between the clutches 0 and 0.
Sun gear shaft 30 and transmission case 18
A multi-disc brake 26 and a one-way clutch 27 are provided between the
A multi-disc brake 28 is provided via. The sun gear 32 provided on the sun gear shaft 30 includes a carrier 33, a planetary pinion 34 supported by the carrier, a ring gear 35 meshing with the pinion, another carrier 36, and a planetary pinion 37 supported by the carrier. , constitutes a two-row planetary gear mechanism together with the ring gear 38 that meshes with the pinion. A ring gear 35 in one planetary gear mechanism is connected to an intermediate shaft 29. Further, the carrier 33 in this planetary gear mechanism is connected to a ring gear 38 in the other planetary gear mechanism, and these carriers and ring gear are connected to an output shaft 39. Further, a multi-disc brake 40 and a one-way clutch 41 are provided between the carrier 36 and the transmission case 18 in the other planetary gear mechanism. Such a hydraulic automatic transmission with an overdrive device engages or releases each clutch and brake according to the engine output and vehicle speed by a hydraulic control device, which will be explained in detail below. It is designed to perform four forward gear shifts including D) or one reverse gear shift by manual switching. Table 1 shows the shift gear positions and the operating conditions of the clutch and brake.

[Table] Here, ◯ indicates that each clutch and brake are in an engaged state, and × indicates that they are in a released state. FIG. 2 is a hydraulic circuit showing an embodiment of a hydraulic control system for an automatic transmission including a torque converter direct-coupled clutch control system of the present invention. This hydraulic control device includes an oil reservoir 100, an oil pump 101, and a pressure regulating valve 2.
00, speed selection valve 210, 1-2 shift valve 220, 2
-3 shift valve 230, throttle valve 240, cutback valve 250, governor valve 260, overdrive shift valve 270, solenoid valve 280, relief valve 290, lock-up shift valve 300, governor control valve 310, D-2 timing valve 320, Check valve 330, 340, 350, 3
60, 370, 380 various valves, clutch 12,
24, 25 and brakes 19, 26, 28, 40
Hydraulic cylinder 12 of a hydraulic servo device that operates
A, 24A, 25A, 19A, 26A, 28A,
40A, oil passages that communicate these various valves and hydraulic cylinders, and the solenoid valve 3 of the present invention
90, an electric circuit 400, and a pressure switch 600. Next, the operation of this hydraulic control device will be explained. Hydraulic control device hydraulic pressure, torque converter 1
The source of hydraulic oil and lubricating oil for each part is oil pump 1.
01 and the oil pump 10 directly by the engine.
1 is driven, it sucks oil from the oil reservoir 100 and discharges it into the oil passage 102. Oil road 102
This oil pressure is the source of all working oil pressure and is called line pressure. The line pressure is adjusted to a predetermined pressure by a pressure regulating valve 200 as described later. Relief valve 29
0 is a relief valve when the line pressure becomes abnormally high. Oil is supplied from oil passage 103 to torque converter 1 and each lubricating location through pressure regulating valve 200 . The speed selection valve 210 consists of a spool 211 that moves by operating the driver's seat lever.
Depending on the lever selection position, the line pressure of the oil passage 102 is changed to the oil passages 104, 105, 106, 10 as shown in Table 2.
It serves as a guide to 7.

[Table] The ○ mark in Table 2 indicates that line pressure is guided to the oil passage marked in that column at each selected position, and the - mark indicates that line pressure is guided to the oil passage marked in that column at the selected position. Indicates that there is no The operation of the transmission at each position is: R position is reverse, N position is neutral, D
Position is forward 4 speed automatic transmission, 2 position is forward 1st speed,
Automatic shifting between the second speed and the L position is the fixed position for the first forward speed. In the D position, line pressure is sent from the oil passage 104 to the hydraulic cylinder 24A, and the clutch 24 is always engaged. Further, in the first, second, and third forward speed states, the clutch 12 is engaged as will be described later. The oil passage 104 changes the line pressure to the 1-2 shift valve 22.
0 and governor valve 260. The 1-2 shift valve 220 is composed of spools 221, 222 and a spring 223. In the first speed, the spool 221 is located at the lower side in the figure and does not guide the pressure oil in the oil passage 104 to either direction. Oil passage 11 in 2nd, 3rd and 4th speeds
The spool 221 moves upward in the drawing due to the action of the governor pressure from the governor pressure 1 and guides the pressure oil in the oil passage 104 to the oil passage 112. The oil passage 112 communicates with the 2-3 shift valve 230 and also with the hydraulic cylinder 28A of the brake 28, and sends pressure oil to the hydraulic cylinder 28A to operate the brake 28. brake 2
8 is engaged, the power transmission mechanism enters the second speed state as shown in Table 1. 2-3 shift valve 23
0 is the spool 231, 232 and spring 2
33, and in 1st speed and 2nd speed the spool 23
1 is located at the bottom in the figure, and in the third and fourth speeds, the spool 23 is
1 moves upward in the drawing, pressure oil in the oil passage 112 is guided to the oil passage 113, and the pressure oil is sent to the hydraulic cylinder 25A of the clutch 25, thereby operating the clutch 25. When the clutch 25 is engaged, the power transmission mechanism is in the third speed state as shown in Table 1. Overdrive shift valve 270 is spool 27
1, sleeve 272, spring 273, oil chamber 2
74, 275, 276, oil chamber 274, 2
75, 276 depending on the pressure oil acting on the oil passage 102.
The communication between the oil passage 117 or the oil passage 118 is switched. Solenoid valve 280 is controlled by an overdrive selector switch 500 provided at the driver's seat. When overdrive selector switch 500 is OFF, opening 284 is closed. Pressure oil is supplied through the oil passage 102 to the oil passage 119 and the check valve 3.
30, oil path 120, check valve 340, oil path 12
The oil chamber 274 of the overdrive shift valve 270 is supplied through the spool 271 and the sleeve 27.
2 as shown below. When overdrive selector switch 500 is ON, opening 284 is opened. Pressure oil in the oil chamber 274 is discharged from the outlet 285 via the oil passage 122, the check valve 340, the oil passage 120, the check valve 330, the oil passage 119, and the opening 284. Throttle pressure is supplied to the oil chamber 274 from the oil passage 108 via the check valve 340 and oil passage 122, and governor pressure is supplied to the oil chamber 276 from the oil passage 111. controlled. When the overdrive selector switch 500 is OFF, the line pressure of the oil passage 102 is acting on the oil chamber 274 of the overdrive shift valve 270, so the spool 271 and the sleeve 272 are held downward in the figure, and the pressure of the oil passage 102 is Oil is oil line 117,
It is sent to the hydraulic cylinder 12A of the clutch 12 through the check valve 370, and the clutch 12 is actuated. When the overdrive selector switch 500 is ON, the oil chamber 2 of the overdrive shift valve 270
Throttle pressure is applied to 74 through an oil passage 108. The spool 271 of the overdrive shift valve 270 is controlled by pressure oil acting on an oil chamber 274 and an oil chamber 276.
In the third speed state, the oil passage 102 is located at the lower part of the diagram.
Pressure oil is sent to the hydraulic cylinder 12A via the oil passage 117 and the check valve 300 to operate the clutch 12. When the governor pressure increases and the spool 271 moves upward in the figure, the oil passage 117 is connected to the oil drain port 278, the clutch 12 is released, and the oil passage 1
02 pressure oil is sent to the hydraulic cylinder 19A of the brake 19 via the oil passage 118 and the check valve 380, and the brake 19 is operated to enter the fourth speed (overdrive) state. In the second position, line pressure is supplied to oil passage 104 and oil passage 105. The pressure oil led to the oil passage 105 is supplied to the hydraulic cylinder 12, and when the oil pressure is acting on the oil chamber 321 of the D-2 timing valve 320 through the oil passage 142, the oil pressure is supplied to the oil pressure cylinder 12. The spools 231 and 2 are guided to the oil chamber 234 of the 2-3 shift valve 230 through the oil passage 143.
32 is held in the downward direction shown in the figure. Also check valve 33
0, oil path 120, check valve 340, oil path 122
Oil chamber 2 of overdrive shift valve 270 via
74 to hold the spool 271 and sleeve 272 in the downward direction shown in the figure. The pressure oil in the oil passage 104 is guided to the hydraulic cylinder 24A of the clutch 24 and also to the 1-2 shift valve 220. When the 1-2 shift valve 220 is not in the first speed state, the pressure oil in the oil passage 104 is sent to the hydraulic cylinder 28A via the oil passage 112, and the brake 28 is operated. Also, the pressure oil in the oil passage 105 is the 2-3 shift valve 2.
The oil is supplied to the hydraulic cylinder 26A of the brake 26 through the 30 oil passages 114 and 115, and the brake 26 is operated. clutch 24, 12, brake 2
6 and 28 are engaged, the power transmission mechanism enters the second speed state as shown in Table 1. When the 1-2 shift valve 220 is in the first speed state, the spool 22
1 moves downward in the figure, and the oil passage 112 becomes the oil drain port 225.
The pressure oil in the hydraulic cylinder 28A is connected to the oil path 1.
12, the oil is discharged from the oil drain port 225, and the brake 28 is released.
The pressure oil in the hydraulic cylinder 26A is discharged from the oil drain port 226, the brake 26 is released, and the power transmission mechanism is placed in the first speed state. In the L position, oil passages 104, 105, 10
Line pressure is introduced to 6. The pressure oil introduced into the oil passage 104 simultaneously operates the clutch 24 at each gear position in the D position. The pressure oil led to the oil passage 105 passes through the oil chamber 234 and holds the spools 231 and 232 of the 2-3 shift valve 230 in the downward direction in the figure, and also holds the spool 2 of the overdrive shift valve 270.
71, hold the sleeve 272 in the downward direction shown in the figure. The pressure oil led to the oil passage 106 is transferred to the 1-2 shift valve 220
The oil acts on the oil chamber 224 to hold the spools 221 and 222 in the downward direction in the figure, and is sent to the hydraulic cylinder 40A of the brake 40 through the oil passage 116 to operate the brake 40. When the clutches 24, 12 and brake 40 are engaged in this manner, the power transmission mechanism is in the first speed state as shown in Table 1. At the R position, line pressure is introduced into the oil passages 106 and 107. The pressure oil led to the oil passage 107 is led to the oil chamber 206 of the pressure regulating valve 200 and acts to increase the line pressure, and is also led to the oil passage 113 via the 2-3 shift valve 230 and operates the clutch 25. Activate. Moreover, the pressure oil in the oil passage 107 is 1-
The oil is guided to the oil passage 116 via the second shift valve 220 and operates the brake 40. Clutch 24 is also actuated. In this way, the clutches 24, 12,
When the brake 40 is engaged, the power transmission mechanism enters the reverse state as shown in Table 1. Governor valve 260 is attached to output shaft 39 in FIG. The governor valve 260 has a hydraulic pressure (governor pressure) that is a function of the output shaft rotational speed due to a balance between centrifugal force, spring force, and hydraulic pressure, that is, a hydraulic pressure that increases as the output shaft rotational speed increases.
is occurring in the oil passage 111. The throttle valve 240 includes a spool 241, a downshift plug 242, and springs 243, 24.
4. Consisting of oil chambers 245 and 246, the force of the spring 244 due to the movement of the downshift plug 242 in conjunction with the movement of the accelerator pedal and the oil chamber 245,
246, a throttle pressure proportional to the throttle opening is generated in the oil passage 108. The throttle pressure of the oil passage 108 is 1
It is connected to the -2 shift valve 220, the 2-3 shift valve 230, and the overdrive shift valve 270, and controls the timing of gear changes according to the engine load state. Also, when a hard down is necessary, if the accelerator pedal is strongly depressed, the downshift plug 242 moves upward and the oil passage 102 communicates with the oil passage 109.
The line pressure of the oil passage 102 is 1- through the oil passage 109.
2 shift valve 220, 2-3 shift valve 230 and check valve 350 to overdrive shift valve 270, and spools 221, 231, 2
A downshift is performed from fourth speed to third speed, from third speed to second speed, or from second speed to first speed in balance with the governor pressure acting on the lower end of gear 71. The cutback valve 250 generates cutback pressure in the oil passage 110 by balancing pressure oil.
The cutback pressure in the oil passage 110 is controlled by the throttle valve 24.
0 to lower the throttle pressure and prevent unnecessary power loss due to the oil pump. The pressure regulating valve 200 generates line pressure in the oil passage 102 by the balance between the pressure oil and the force of the spring 203. The check valves 370 and 380 are check balls,
Each consists of an orifice and a hole. Next, a control circuit for the direct coupling clutch 50 of the torque converter 1, which is the gist of the present invention, will be explained. The lock-up shift valve 300 is a spool 30.
1, a spring 302, and oil chambers 303 and 304, and line pressure is always applied to the oil chamber 303. When the line pressure is not acting on the oil chamber 304, the spool 301 is positioned downward in the figure due to the line pressure acting on the oil chamber 303, and communicates the oil passage 103 and the oil passage 130. The pressure oil in oil passage 103 is oil passage 1.
30, the direct coupling clutch 50 is released, the oil circulates within the torque converter 1, and the oil is connected to the oil passage 1 via the oil passage 131.
It is discharged from 32. When line pressure acts on the oil chamber 304, the spool 301 is moved upward in the drawing by the spring 302, thereby connecting the oil passage 103 and the oil passage 131. Pressure oil in oil passage 103 operates direct coupling clutch 50 via oil passage 131. The governor control valve 310 is connected to the spool 31
1, a spring 312, and an oil chamber 313, and when the governor pressure acting on the oil chamber 313 is below a predetermined value, the spool 311 is positioned upward in the figure by the spring 312 to cut off the oil passage 113. Oil chamber 3
When the governor pressure acting on the spool 13 exceeds a predetermined value, the spool 311 moves downward in the drawing against the spring 312 to connect the oil passage 113 to the oil passage 140. The solenoid valve 390 includes a valve port 391 provided to discharge hydraulic pressure from the oil passage 140, a moving core 392 that opens and closes the valve port, and a moving core 392 that opens and closes the valve port.
Spring 39 that urges valve 92 toward valve port 391
3. Oil drain port 394 and electromagnetic solenoid 395
When energized, the valve port 391 is opened and the oil pressure in the oil passage 140 is drained from the oil drain port 394, and when the electricity is not energized, the valve port 391 is closed and the oil pressure in the oil passage 140 is drained. hold. During 1st and 2nd forward speed... Lock-up shift valve 3 is closed due to no pressure oil being supplied to oil passage 113.
Pressure oil does not act on the oil chamber 304 of 00, and the oil chamber 30
Due to the line pressure acting on the spool 301, the spool 301 is positioned at the lower side in the figure and communicates between the oil passage 103 and the oil passage 130. Pressure oil supplied from the oil passage 103 passes through the oil passage 130, releases the direct coupling clutch 50 of the torque converter 1, circulates within the torque converter 1, passes through the oil passage 131, and is connected to the lock-up shift valve 3.
00 and is discharged from the oil drain port 132. That is, the direct coupling clutch 50 is released during the first and second forward speeds. At 3rd forward speed...In the 3rd forward speed state, the vehicle speed increases and the sprue 31 of the governor control valve 310
1 moves downward in the figure, the oil passage 113 communicates with the oil passage 140. The solenoid valve 390 is de-energized, the oil pressure in the oil passage 140 is maintained, acts on the oil chamber 304 of the lock-up shift valve 300, moves the spool 301 upward in the figure, and connects the oil passage 103 to the oil passage 131. Direct connection clutch 5
0 is engaged. 3-4 During upshifting...The vehicle speed increases from the 3rd forward speed state (direct coupling clutch 50 engaged) and the spool 27 of the overdrive shift valve 270
1 moves upward in the figure to oil passage 102 or oil passage 11.
8 and the oil passage 117 communicates with the oil drain port 278, the hydraulic pressure in the hydraulic cylinder 12A of the clutch 12 is discharged, and pressure oil is gradually supplied to the hydraulic cylinder 19A of the brake 19. When the pressure in the hydraulic cylinder 19A increases to a predetermined value, a pressure switch 600 attached to the hydraulic cylinder is activated. Using the action of the pressure switch 600 as an input signal, the electric circuit 400 energizes the solenoid valve 390 for a predetermined period of time to exhaust pressure from the oil passage 140 . As a result, the spool 30 of the lock-up shift valve 300
1 moves downward in the figure to connect oil passage 103 and oil passage 131 for a predetermined period of time, and also connects oil passage 130 to oil drain port 132, and the direct coupling clutch is temporarily released for a predetermined period of time. The brake 19 completes engagement within the release time of the direct coupling clutch 50, thereby preventing impact during the 3-4 upshift. Electric circuit 400 causes solenoid valve 390
After the energization ends, hydraulic pressure is generated in the hydraulic pressure 140, and the spool 301 returns to the upper position in the figure, and the direct coupling clutch 5
0 is re-engaged. In this manner, the 3-4 upshift is performed while the direct coupling clutch 50 is released, and is re-engaged after the gear shift is completed. 4-3 When downshifting...The vehicle speed decreases from the 4th forward speed state (direct coupling clutch 50 engaged),
Spool 27 of overdrive shift valve 270
1 moves downward in the figure, and the oil passage 118 becomes the oil drain port 2.
79 and the oil passage 102 communicates with the oil passage 117, the pressure oil in the hydraulic cylinder 19A is discharged and the pressure oil is supplied to the hydraulic cylinder 12A. When the oil pressure of the hydraulic cylinder 19A decreases, the pressure switch 600 returns, and when this return signal is input, the electric circuit 400 energizes the solenoid valve 390 for a predetermined period of time to discharge the oil pressure in the oil passage 140. As a result, the spool 301 of the lock up shift valve 300 moves downward in the figure, similar to the 3-4 upshift described above, and the direct coupling clutch 50 is temporarily released for a predetermined time. Furthermore, the brake 19 is released by the hydraulic pressure in the hydraulic cylinder 19A, and the hydraulic pressure in the hydraulic cylinder 12A increases and the clutch 12 is engaged to enter the third speed state and complete the 4-3 downshift. After the energization to the solenoid valve 390 is stopped, the pressure in the oil passage 140 is increased again to move the spool 301 of the lock-up shift valve 300 upward in the figure, connecting the oil passage 103 and the oil passage 131, and connecting the direct coupling clutch 50 again. engage. That is, during a 4-3 downshift, the gear change is performed while the direct coupling clutch 50 is released, and after the shift is completed, the direct coupling clutch 50 is engaged again. Next, an electric circuit 400 for controlling the solenoid valve 390 will be explained based on an example shown in FIGS. 3 to 5. In FIG. 3, 600 and 390 are the pressure switch and solenoid valve, and the electric circuit 400
consists of monostable multivibrators 410 and 420 that use the opening and closing of the pressure switch as input signals, an OR circuit 430 that receives the outputs of the monostable multivibrators 410 and 420, and amplifies the output to actuate the solenoid valve 390. Consists of a amplifier. Figure 4 shows a circuit example of each element, R is a resistance,
C indicates a capacitor, and T indicates a transistor. The operation of this electric circuit 400 will be explained with reference to FIG. When hydraulic pressure is supplied to the hydraulic cylinder 19A and the pressure switch 600 is turned ON, the voltage at point B becomes 0 volts (earth potential), and when the hydraulic cylinder 19A is exhausted, the pressure switch 600 is turned OFF and B
The potential at the point is 5 volts, which is the power supply potential. Therefore, as the brake 19 is engaged and released by the 3-4 upshift and the 4-3 upshift, the voltage at point B, which is the output signal of the solenoid valve 390, becomes as shown in FIG. 5I. This output signal is input to monostable multivibrators 410 and 420. Monostable multivibrators 410 and 42
The monostable multivibrator 410 has an input position b that emits a pulse of constant width t ₁ at the rising edge of the input, and an input position a that emits a pulse of constant width t ₂ at the falling edge of the input. The other monostable multivibrator 420 is input to the a position. As a result, the output waveforms of each monostable multivibrator become as shown in and in FIG. 5, and these outputs are input to the OR circuit 430. OR circuit 430 is NOT circuit 431 and 43
2. It is composed of a NAND circuit 433, and the input signal inverted by each NOT circuit 431 and 432 as shown in FIG. 5 becomes an output signal in the NAND circuit 433 as shown in FIG. It is amplified by an amplifier 440 composed of a transistor, and is amplified by 3-4 as shown in FIG.
The solenoid valve 390 is energized for hours _T1 and _T2 during upshift and 4-3 downshift, respectively. Next, other embodiments of the present invention will be described. As shown in FIG. 4, a manual switch 700 is provided, and when the manual switch 700 is ON, the NAND circuit 430 maintains an output of 5 volts regardless of the position of the pressure switch. As a result, when the driver closes the manual switch 700, the solenoid valve 390 is always activated to prevent the direct coupling clutch 50 from operating, thereby providing selectivity in the use of the direct coupling clutch and improving drivability. The direct-coupling clutch control device of the present invention can be applied to a torque converter with a direct-coupling clutch that has two or more gears and in which the direct-coupling clutch is engaged at two or more gears to prevent shocks during shifting between each gear. . As mentioned above, the torque converter direct-coupled clutch control device of the present invention controls the lock-up shift valve by operating the solenoid valve using an electric circuit that receives the pressure switch opening/closing signal as input. The hydraulic circuit can also be simplified. Additionally, a manual switch is provided in the electric circuit, allowing the driver to freely release the direct coupling clutch at will, improving drivability.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a hydraulic automatic transmission with an overdrive device equipped with a clutch directly connected to a torque converter, Fig. 2 is a hydraulic control circuit diagram of an automatic transmission including a clutch control device directly connected to a torque converter of the present invention, and Fig. 3 4 is a block diagram showing the configuration of the electric circuit, FIG. 4 is a circuit diagram thereof, and FIG. 5 is a waveform diagram showing the operation of the circuit. In the figure, 1... Torque converter, 50... Torque converter direct coupling clutch, 260... Governor valve,
300...Lock-up shift valve, 310...Governor control valve, 390...Solenoid valve,
400...Electric circuit, 600...Pressure switch.

Claims (1)

[Claims] 1. In an automatic transmission equipped with a torque converter with a direct coupling clutch and a planetary gear transmission mechanism having a low-speed hydraulic servo and a high-speed hydraulic servo, an oil passage to which a signal hydraulic pressure for engaging the direct coupling clutch is supplied, and a lock-up shift valve that is connected to the oil passage and switches the engagement and release of the direct coupling clutch according to the signal oil pressure in the oil passage; a solenoid valve that is provided to discharge the oil pressure in the oil passage; and a high-speed hydraulic pressure. A switch that operates when the oil pressure in the servo exceeds a predetermined value, and electricity that controls the solenoid valve to discharge the oil pressure in the oil passage for a predetermined period of time when the switch is switched from OFF to ON or from ON to OFF. 1. A torque converter direct-coupling clutch control device for an automatic transmission, comprising a circuit for releasing a direct-coupling clutch for a predetermined period of time when shifting between low and high speeds.