JPH0141863B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a mechanism for controlling a direct coupling clutch of an automatic transmission equipped with a torque converter with a direct coupling clutch employed in a vehicle such as an automobile. [Prior Art] Conventionally, in an automatic transmission equipped with a torque converter with a direct coupling clutch, a lockup control valve is provided to control the direct coupling clutch in accordance with the vehicle speed. [Problems to be Solved by the Invention] However, the switch valve that switches between engagement and release of the direct coupling clutch using the hydraulic pressure output from the lockup control valve does not operate reliably, causing valve stuck, etc. If the clutch remained engaged, there were problems such as the engine stopping when restarting the vehicle, and the hydraulic oil in the torque converter not being circulated and overheating. Therefore, by providing a fail-safe valve in the direct coupling clutch control mechanism, even if the switch valve causes valve stay when the direct coupling clutch is engaged, the direct coupling clutch will be reliably released, thereby preventing engine stop when restarting. It is an object of the present invention to provide a clutch control mechanism directly connected to a torque converter of an automatic transmission, which can prevent overheating of the hydraulic oil because the circulation of the hydraulic oil in the torque converter can be ensured at all times. [Means for Solving the Problems] In order to achieve the above object, the present invention provides a hydraulic control circuit for an automatic transmission with multiple forward speeds and one reverse speed having a torque converter with a direct coupling clutch. The direct-coupled clutch control mechanism includes a hydraulic power source, a switch valve for switching between communication between the hydraulic source oil passage and the direct-coupled clutch engagement oil passage, and communication between the hydraulic source oil passage and the direct-coupled clutch release oil passage, and the switch valve. A lock-up control valve that outputs hydraulic pressure so as to be in a lock-up state connects the hydraulic source oil path and the direct clutch engagement oil path, and the lock-up control valve communicates with the above three oil paths via a switch valve. When the switch valve is in the locked-up state and the valve stays in the state where the output is stopped, the communication between the hydraulic source oil path and the oil path for engaging the direct coupling clutch is cut off, and the hydraulic source oil path and the direct coupling clutch are disconnected from each other. It is characterized by comprising a fail-safe valve that outputs an output to communicate the release oil path. [Operations and Effects] When the torque converter shifts from the direct coupling state to the torque converter state due to a decrease in vehicle speed, even if the switch valve is in the direct coupling clutch engagement position and the valve stays, the hydraulic source oil path and the direct coupling clutch engagement position are not connected. A fail-safe valve is provided that disconnects the common oil passage and connects the oil pressure source oil passage with the direct coupling clutch release oil passage, so even if the switch valve becomes valve stuck, the direct coupling clutch will not be released. This has the effect of ensuring that the engine is released and preventing the engine from stopping when starting, and that the circulation of the hydraulic oil within the torque converter can be ensured at all times, thereby preventing overheating of the hydraulic oil. [Example] Next, the present invention will be explained based on an example shown in the drawings. 1 is a torque converter of a hydraulic automatic transmission, 5
is a pump impeller connected to the engine crankshaft 8, 6 is a turbine, 7 is a stator, 50 is a torque converter direct coupling clutch that directly connects the engine crankshaft 8 and the turbine shaft 9, and 60, 70, and 80 are each of the present invention. The main points are switch valves, lock-up control valves, and fail-safe valves. In this embodiment, the switch valve 60 has a spring 600 placed on its back in the upper part of the figure, and four lands 61, 62, 63, 64.
Line pressure from a hydraulic source is supplied to the land 61 via a spool 601 equipped with a spool 601, an oil passage 102, and when the spool 601 is in the lower position in the figure, the oil passage 91, three-way check valve 390, and oil passage 97 to the oil chamber 8 of the fail-safe valve 80
Upper end oil chamber 65 and land 61 that send line pressure to 16
is formed between the land 62 and the land 62, and communicates with the oil passage 91 when the spool 601 is in the upper position in the figure.
The second oil chamber 66 and land 62 are always in communication with
is formed between the land 63 and the spool 60, and is always in communication with the direct coupling clutch release oil passage 87.
A third oil chamber that communicates with the oil passage 92 when 1 is in the upper part of the diagram, and with the torque converter supply pressure oil passage 103 when it is in the lower part of the diagram to conduct the torque converter hydraulic pressure to the direct coupling clutch release oil passage 87. 67,
It is formed between the land 63 and the land 64, and always communicates with the oil passage 88 for engaging the direct coupling clutch, and when the spool 601 is in the upper position in the figure, the oil passage 94,
The fail-safe valve 80 communicates with the torque converter supply pressure oil passage 103 via the oil chamber 813 and oil passage 93 when the spool 801 is in the upper part of the figure, and the oil passage 95 and the oil cooler communication oil passage 125 when it is in the lower part of the figure. Hydraulic pressure is supplied through the fourth oil chamber 68, the lock-up control valve 70, and the oil passage 96, which are in communication with the engine, during driving conditions in which the direct coupling clutch should be engaged (for example, during high-speed steady driving in overdrive). It consists of a lower end oil chamber 69 connected to the hydraulic servo of the control circuit. In addition, in this embodiment, the lock-up control valve 70 is provided with a spring 70 at the bottom as shown in the figure.
A spool 701 has two lands 71 and 72, and the land 71 is connected to the land 71 through an oil passage 111.
An upper end oil chamber 73 is formed between lands 71 and 72 to which governor pressure applied to the oil passage 96 is supplied.
It communicates with the three-way check valve 390 via B, and is always in communication with the oil passage 96 that communicates with the lower end oil chamber 69 of the switch valve 60, and when the spool 701 is in the upper position in the figure, it communicates with the oil drain port 76, When it is below, the direct coupling clutch 5 is connected via the oil passage 118B.
The second oil chamber 74, which is connected to the hydraulic servo of the frictional engagement device of the hydraulic control circuit of the control device that operates when the gear is shifted to the gear position where zero engagement is to be performed, is constantly in communication with the oil passage 117B. In the example, oil passage 117 and check valve 37 are controlled by the 3-4 speed shift valve.
0 and a lower end oil chamber 75 to which line pressure applied to the land 72 is supplied through the oil passage 117B when the land 72 is in gear other than 4th speed. In addition, in this embodiment, the fail-safe valve 80 has a spring 800 installed on its back in the lower part of the drawing.
A spool 801 having three lands 81, 82, 83, 84, 85, and an upper end oil pressure 81 to which line pressure applied to the land 81 is supplied via an oil path 102B.
1. A second oil chamber 81 formed between the land 81 and the land 82, always in communication with the oil passage 95, and communicating with the oil passage 94 when the spool 801 is in the lower position in the figure.
2. The oil passage 93 is formed between the lands 82 and 83 and is always in communication with the torque converter supply pressure oil passage 103 via the switch valve 60, and when the spool 801 is in the upper position in the figure, the oil is A third oil chamber 813, land 83, and land 8, which communicate with passage 94 and, when located in the lower part of the drawing, communicate with oil passage 92.
4 and constantly communicates with the oil drain port 818,
When the spool 801 is at the top in the figure, the oil path 92
A fourth oil chamber 814 and a land 84 communicate with the valve stopper chamber 815 when located in the lower part of the figure.
A fifth oil chamber 816 is formed between the land 85 and the land 85, and communicates with the three-way check valve 390 through the oil passage 97 when the spool 801 is in the upper position in the figure, and is closed when the spool 801 is in the lower position in the figure, through the oil passage 102B. The lower end oil chamber 8 is supplied with line pressure applied to the land 85.
It consists of 17. Next, the effect will be explained. As shown in FIG. 1, when the vehicle speed is lower than a low value and the governor pressure is lower than the set value, or when the gear is not shifted to a gear position in which the direct coupling clutch should be engaged, the lock-up control valve 70 is closed to the oil passage 111. The spool 701 is set upward in the figure due to the action of the spring 700 when the oil pressure supplied to the oil chamber 73 via the oil passage 117B is low, or due to the line pressure supplied to the oil chamber 75 via the oil passage 117B. Since the oil passage 96 is closed and the switch valve 60 does not generate oil pressure in the oil chamber 69, the spring 6
00 and the line pressure supplied to the oil chamber 65, it is set at the lower position in the figure. The torque converter supply pressure oil is supplied from the oil passage 103 → the oil chamber 67 of the switch valve 60 →
The oil flows in the order of oil passage 87, and direct coupling clutch 50 is released. In this case, in the fail-safe valve, the force acting on the spool 801 downward in the figure due to the line pressure supplied to the oil chamber 811 via the oil passage 102 and the oil passage 102B is greater than the force acting on the oil passage 102 → the switch valve 60. The line pressure supplied to the oil chamber 816 via the oil chamber 65 → oil passage 91 → three-way check valve 390 → oil passage 97, and the line pressure supplied to the oil chamber 817 via the oil passage 102 and oil passage 102B. spring 800
Since the resultant force acting upwardly in the figure on the spool 801 is large, the spool 801 is set upward in the figure. As shown in FIG. 2, when the vehicle speed is higher than a certain value and the automatic transmission is shifted to a gear position in which the direct coupling clutch should be engaged, the governor pressure is higher than the set value, and the lock-up control valve 70 is generated in the oil chamber 73. Due to the high oil pressure, the spool 701 is set to the lower position in the figure, and the switch valve 60 moves from the oil passage 118B to the oil chamber 74.
→The spool 601 is set upward in the drawing by the line pressure supplied to the oil chamber 69 via the oil passage 96. Therefore, the pressure oil supplied to the torque converter is
→Oil passage 93→Oil chamber 813→Oil passage 94→Oil chamber 68→
The oil flows in the order of oil passage 88, and direct coupling clutch 50 is engaged. In this case, in the fail-safe valve, the force acting in the downward direction in the figure on the spool 801 due to the line pressure supplied to the oil chamber 811 via the oil path 102 and the oil path 102B is greater than the force applied by the oil path 118B→oil chamber 74→ The line pressure supplied to the oil chamber 816 via the oil passage 96 → oil passage 96B → three-way check valve 390 → oil passage 97, and the line pressure supplied to the oil chamber 817 via the oil passage 102 and oil passage 102B. Since the resultant force acting upwardly in the figure on the spool 801 by the spring 800 is large, the spool 801 is set upward in the figure. Next, the operation when the switch valve becomes valve stuck will be explained. As shown in Figure 3,
The torque converter 1 is in a direct connection state, the spool 601 of the switch valve 60 is set upward in the figure, the spool 701 of the lock-up control valve 70 is set downward in the figure, and the spool 8 of the fail-safe valve 80 is set upward in the figure.
01 is the lock-up control valve 7 which is set at the upper position in the figure and is used when the vehicle speed decreases and the direct connection state changes to the torque converter state.
0, the spool 701 operates normally and the spool 701 moves upward in the figure, and when a valve stick occurs in the switch valve 60 and the spool 601 is stuck in the upward direction in the figure, the failsafe valve 80 operates from the oil passage 91 or the oil passage 96B to the three-way check valve. 390, the line pressure that was being supplied to the oil chamber 816 via the oil passage 97 is stopped, and the line pressure is supplied to the oil chamber 816 via the oil passage 102 and the oil passage 102B.
The line pressure supplied to spool 80
Due to the line pressure supplied to the oil chamber 817 via the oil passage 102 and the oil passage 102B and the spring 800, the resultant force acting on the spool 801 in the upward direction in the figure becomes smaller than the force acting on the spool 801 in the downward direction in the figure.
1 is set at the bottom in the figure, and the valve stopper 819
It is fixed in the downward direction as shown in the figure. The pressure oil supplied to the torque converter 1 is oil passage 103 → oil passage 93 → oil chamber 813 → oil passage 92 → oil chamber 67 → oil passage 87 → torque converter 1 → oil passage 88 → oil chamber 68 → oil passage 94 →
Oil chamber 812 → Oil passage 95 → Oil cooler communication oil passage 1
25, the engagement of the direct coupling clutch 50 is released, and the torque converter state is established. As described above, even if the switch valve 60 sticks in the engagement position of the direct coupling clutch 50, the failsafe valve 80 operates, the direct coupling clutch 50 is released, and the automatic transmission operates in a completely normal torque converter state. Next, an example of a control device for an automatic transmission equipped with the direct clutch control mechanism of this embodiment will be explained with reference to FIGS. 4 and 5. This automatic transmission has 1 torque converter with direct coupling clutch, 2 overdrive mechanisms, 3 forward speeds and 1 reverse speed.
The torque converter 1 includes a pump 5, a turbine 6 and a stator 7.
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 forms the output shaft of the torque converter 1, which also serves as the input shaft of the overdrive mechanism 2, and serves as the carrier 10 of the planetary gear system in the overdrive mechanism.
is connected to. 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. A pralinear pinion 14 rotatably supported by a carrier 10 meshes with a sun gear 11 and a ring gear 15. Sungear 11 and Carrier 1
Between 0 and 0, there is a multi-disc clutch 12 and a one-way clutch 1.
3, and a multi-disc brake 19 is further provided between the sun gear 11 and the housing or overdrive case 16 containing the overdrive mechanism.
is provided. 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 pralinear pinion 34 supported by the carrier, a ring gear 35 meshing with the pinion, another carrier 36, and a pralinear pinion 34 supported by the carrier. The pinion 37 and the ring gear 38 meshing with the pinion constitute a two-row planetary gear mechanism. A ring gear 35 in one planetary gear mechanism is connected to an intermediate shaft 29. Also, 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. In such a hydraulic automatic transmission with an overdrive device, each clutch and brake are engaged or released 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 transmission gear position and the operating status of the clutch and brake.

[Table] Here, ○ indicates that each clutch and brake are in the engaged state, and × indicates that they are in the released state.
This hydraulic control circuit is connected to the oil sump 10 as shown in FIG.
0, oil pump 101, pressure adjustment valve 200, speed selection valve 210, 1-2 shift valve 220, 2-3 shift valve 230, throttle valve 240, cutback valve 2
50, governor valve 260, overdrive shift valve 270, solenoid valve 280, relief valve 29
0. Switch valve 60, lock-up control valve 70 and fail-safe valve 80 according to the present invention, and check valves 330, 340, 350, 360, 37 having orifices and check balls
0,380, various valves of three-way check valve 390 and other clutches 12, 24, 25 and brake 1
Hydraulic cylinder 12A, which is a hydraulic chamber of a hydraulic piston of a hydraulic servo that operates 9, 26, 28, 40;
24A, 25A, 19A, 26A, 28A, 40
It is composed of various hydraulic circuits arranged between A and these various valves and hydraulic cylinders. The operation of this hydraulic control circuit will be explained below. The source of the hydraulic pressure for the hydraulic control circuit, hydraulic oil for the torque converter 1, and lubricating oil for each part is the oil pump 101, which is directly supplied by the engine to the oil pump 1.
01 is driven, it sucks oil from the oil reservoir 100 and discharges it to the oil passage 102. Oil road 10
Oil pressure 2 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 2
90 is a relief valve used when line pressure becomes abnormally high. Oil passage 103 passes through pressure regulating valve 200
Oil is supplied to the torque converter 1 and each lubricating point. The speed selection valve 210 consists of a spool 211 that moves by operating the driver's seat lever, and depending on the lever selection position, the line pressure of the oil passage 102 is changed to the oil passages 104, 105, 106, etc. as shown in Table 2.
It serves as a guide to 107.

[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 shaft 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. When the brake 28 is engaged, the power transmission mechanism enters the second speed state as shown in Table 1. 2-3 shift valve 2
30 consists of spools 231, 232 and a spring 233, and in the first and second speeds, the spool 2
31 is located at the bottom in the figure, and in the third and fourth speeds, the spool 2 is
31 has moved upward in the figure, and the oil passage 112
The pressure oil is introduced into the oil passage 113, and the pressure oil is sent to the hydraulic cylinder 25A of the clutch 25 to operate 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 applied to 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. The pressure oil supplied through the oil passage 102 is supplied 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 11
7, the oil is sent to the hydraulic cylinder 12A of the clutch 12 and the oil chamber 75 of the lock-up control valve 70 via the check valve 370 and the oil passage 117B.
is activated and the lock-up control valve 70 closes to the spool 7.
01 is held upward in the drawing, the direct coupling clutch is released, and the engine is operated in a torque converter state. When the overdrive selector switch 500 is ON, the oil chamber 2 of the overdrive shift valve 270
Throttle pressure is applied to the oil passage 74 from the 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 supplied to oil passage 117, check valve 370, and oil passage 1.
17B to the hydraulic cylinder 12A and the oil chamber 75 of the lock-up control valve 70.
is operated, and the lock-up control valve 70 holds the spool 701 at the upper position in the figure. 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, the oil pressure in the oil chamber 75 is exhausted, and the pressure oil in the oil passage 102 is discharged. Oil road 11
8. When the pressure is sent to the hydraulic cylinder 19A of the brake 19 through the check valve 380 and the oil path 118B, and the brake 19 is activated and enters the fourth speed (overdrive) state, and the governor pressure exceeds the set value,
In the lock-up control valve 70, the spool 701 is controlled by the governor pressure acting on the oil chamber 73 and the spring 700 to operate and maintain the lock-up control valve 70 in the downward direction shown in the figure. It acts on the oil chamber 816 through the oil passage 96, the oil passage 96B, the three-way check valve 390, and the oil passage 97 to operate the switch valve 60 and the fail-safe valve 80, thereby changing the torque converter supply pressure to the oil chamber 69. Leading from the passage 103 to the oil passage 88, the direct coupling clutch 50 is engaged. 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 led to the oil chamber 234 of the 2-3 shift valve 230, and holds the spools 231 and 232 in the downward direction in the figure.
The spool 27 is also guided to the oil chamber 274 of the overdrive shift valve 270 via the check valve 330, oil passage 120, check valve 340, and oil passage 122.
1. Hold the sleeve 272 in the lower position shown in the figure. The pressure oil in the oil passage 104 is supplied to the hydraulic cylinder 24 of the clutch 24.
A and 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. Further, the pressure oil in the oil passage 105 is supplied to the hydraulic cylinder 26A of the brake 26 via the 2-3 shift valve 230 and the oil passages 114 and 115, and the brake 26 is operated. When the clutches 24, 12 and the brakes 26, 28 are engaged, the power transmission mechanism is in the second speed state as shown in Table 1. When the 1-2 shift valve 220 is in the first speed state, the spool 221 moves downward in the figure, and the oil passage 112 moves to the oil drain port 2.
25, the pressure oil in the hydraulic cylinder 28A is discharged from the oil drain port 225 via the oil path 112, the brake 28 is released, and the oil path 115 is connected to the oil drain port 225.
26, 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 enters 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 guided 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 12 is also actuated. In this way, the clutches 25, 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. In addition, when a hard down is necessary, if the accelerator pedal is strongly depressed, the downshift plug 242 moves upward and the oil passage 102 connects with the oil passage 109, and the line pressure of the oil passage 102 passes through the oil passage 109 to the 1-2 shift valve 220, The spools 221, 23 are guided to the overdrive shift valve 270 via the 2-3 shift valve 230 and the check valve 350.
1,271, downshifts are performed from 4th gear to 3rd gear, from 3rd gear to 2nd gear, or from 2nd gear to 1st gear. The cut pack valve 250 generates cut back pressure in the oil passage 110 by balancing the 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. As described above, in the torque converter direct-coupled clutch control mechanism of the present invention, in the hydraulic control circuit of an automatic transmission, the upper end oil chamber 65 of the switch valve 60 is connected to the oil passage 10.
The lock-up control valve 70 has an upper end oil chamber 73 connected to a governor 260 via an oil passage 111, and a fail-safe valve 8.
0, the upper end oil chamber 811 and the lower end oil chamber 817 are connected to the oil passage 102B to be supplied with line pressure, and the oil chamber 74 is connected to the hydraulic servo of the brake 19 to which hydraulic pressure is supplied in overdrive via the oil passage 118B. be contacted and used. As described above, the torque converter direct coupling clutch control mechanism of the automatic transmission of the present invention includes a switch valve that switches the oil path from the hydraulic source to the torque converter to control the engagement and release of the direct coupling clutch, and the operation of the switch valve. In addition to the lock-up control valve to be controlled, a fail-safe valve is added that operates only in the event of an abnormality in which the switch valve causes valve sticking when the direct coupling clutch is engaged. The direct-coupled clutch is released and the torque converter with the direct-coupled clutch operates as a torque converter, so it is fail-safe, the circulation of the hydraulic oil is ensured, and overheating of the hydraulic oil is prevented. Prevented. Also, since a valve stopper is installed, the spool of the fail-safe valve does not return to its normal position even when the engine is turned off, making it safe. The three-way check valve provided in the above embodiment has the effect of simplifying the structure by reducing the number of oil chambers and lands of the fail-safe valve.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing the operation of the torque converter direct coupling clutch control mechanism of the present invention when the direct coupling clutch is released, Fig. 2 is a circuit diagram showing the operation when the direct coupling clutch is engaged, and Fig. 3 is a circuit diagram showing the operation when the direct coupling clutch is engaged. Figure 4 is a schematic diagram of an automatic transmission with four forward speeds;
FIG. 5 is a hydraulic circuit diagram of the automatic transmission control device. In the figure, 50...Torque converter direct coupling clutch, 60...Switch valve, 70...Lockup control valve, 80...Failsafe valve, 87...Torque converter direct coupling clutch release oil passage, 88...
...Oil passage for clutch engagement directly connected to the torque converter.

Claims (1)

[Scope of Claims] 1. A hydraulic control circuit for an automatic transmission with multiple forward speeds and one reverse speed having a torque converter with a direct coupling clutch, comprising: a hydraulic pressure source; and communication between the hydraulic source oil passage and the direct coupling clutch engagement oil passage; A switch valve for switching between communication between the hydraulic source oil path and the direct coupling clutch release oil path, and outputting hydraulic pressure so that the switch valve is in a lock-up state communicating the hydraulic source oil path and the direct coupling clutch engagement oil path. The lock-up control valve is in communication with the above three oil passages via the switch valve, and when the lock-up control valve stops outputting and the switch valve is in the lock-up state and valve stay occurs, the hydraulic power source An automatic transmission comprising a fail-safe valve that disconnects the oil passage from the oil passage for engaging the direct coupling clutch and connects the hydraulic source oil passage to the oil passage for releasing the direct coupling clutch. Clutch control mechanism directly connected to torque converter. 2. Claim 1, characterized in that the fail-safe valve is provided with a valve stopper that stops the valve in a state where the valve outputs an output so as to communicate with the hydraulic power source circuit and the direct coupling clutch release oil path. Clutch control mechanism directly connected to torque converter.