JPH0647347B2 - Hydraulic control of automatic transmission - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

TECHNICAL FIELD The present invention relates to an improvement in a hydraulic control device for an automatic transmission of a vehicle having a function capable of acting an engine exhaust brake.

[Prior art]

Conventionally, especially in large vehicles and vehicles that use a diesel engine, in order to increase the effect of engine braking, the valve provided in the middle of the exhaust pipe is closed to block the flow of exhaust gas, and the internal resistance of the engine is reduced. A vehicle that can act as an engine exhaust brake (exhaust retarder) for increasing the vehicle speed and decelerating the vehicle has been put into practical use. Generally, this engine exhaust brake includes a main switch (manual switch), a throttle switch that is turned on when the accelerator pedal is fully closed in conjunction with the accelerator pedal, and a switch that is turned on when the vehicle speed is equal to or higher than a predetermined value. Are configured to operate when both are ON. On the other hand, a gear transmission mechanism and a plurality of friction engagement devices are provided,
An automatic transmission for a vehicle, which is configured to selectively switch the engagement of the friction engagement device by operating a hydraulic control device to achieve any one of a plurality of shift speeds, has been widely put into practical use. There is. The friction engagement device generally includes two sets of friction plate elements that are supported so as to be rotatable relative to each other, and a hydraulic servo device that drives the friction plate elements, and a hydraulic pressure is supplied to the hydraulic servo device. Then, the two sets of friction plate elements are strongly pressed against each other, and are coupled so that torque can be transmitted between them. Conventionally, line pressure is generally used as the hydraulic pressure for such a friction engagement device. This line pressure was adjusted by the primary regu- lator valve to automatically adjust the basic hydraulic pressure generated by the oil pump to the vehicle speed or the engine load (slottle opening). As a result, it has the minimum necessary pressure even when the throttle is fully closed so that smooth shift control can be performed, and the maximum pressure is the required pressure in the state that includes the full throttle opening and maximum throttle stall. Is controlled so that Generally, the line pressure for engaging the friction engagement device is
This is set when the engine exhaust brake is not operating. This is because the engine exhaust brake acts very little over the entire travel time, and
If the working oil pressure of the friction engagement device is set in accordance with the characteristics of the engine exhaust brake during this short period of time, the oil pressure setting becomes too high during most of the running, which is inconvenient in terms of fuel consumption, shifting feeling, etc. Is caused.

[Problems to be Solved by the Invention]

However, conventionally, since the action and non-action of the engine exhaust brake have not been taken into consideration in setting the line pressure as described above, when the engine exhaust brake acts by satisfying the predetermined condition. In addition, since the reverse drive torque of the engine increases (about twice) as compared with the time of non-operation, the torque to be transmitted by the friction engagement device also increases accordingly and the friction engagement device is engaged. However, there was a problem that the oil pressure in the tank was insufficient and the durability could be disadvantageous. By the way, as a conventional technique that considers the control of the engine exhaust brake and the control of the automatic transmission in combination, for example, there is a disclosure in Japanese Patent Publication No. 58-28414. However, this disclosure involves the detection of the downshift operation of the automatic transmission with respect to the selection of the action or non-action of the engine exhaust brake, and the hydraulic pressure applied to the friction engagement device during the action or non-action of the engine exhaust brake. Makes no suggestion of changing.

[Object of the Invention]

The present invention has been made in view of such a conventional problem, and a good friction engagement device is provided even when an engine exhaust brake is applied while maintaining good fuel economy during normal traveling or gear shifting feeling. It is an object of the present invention to provide a hydraulic control device for an automatic transmission that can maintain excellent durability.

The present invention detects whether or not an engine exhaust brake is in operation in a hydraulic control device for an automatic transmission of a vehicle having a function capable of operating the engine exhaust brake. The above object is achieved by including means and means for increasing the line pressure control hydraulic pressure of the hydraulic pressure control device when the engine exhaust brake is in operation.

[Action]

In the present invention, it is detected whether or not the engine exhaust brake is in operation, and only when the engine exhaust brake is in operation, the line pressure control hydraulic pressure of the hydraulic control device is increased, and Since the line pressure is increased, the normal line pressure with good fuel economy or shift feeling is generated during normal driving, and the line pressure is increased only when a strong hydraulic pressure is required. The durability of the engagement device can be ensured. Further, since the line pressure control hydraulic pressure is increased as a means for increasing the line pressure, it is not necessary to provide a separate circuit or the like, and the line pressure can be increased by an extremely slight design change. You can

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. First, FIG. 2 shows an overall outline of an automatic transmission for a vehicle to which this embodiment is applied. This automatic transmission includes a torque converter 20 as a transmission portion thereof and an overdrive mechanism 40.
And an underdrive mechanism 60 having three stages of forward movement and one stage of reverse movement. The torque converter 20 includes a pump 21 and a turbine 2.
2, a stator 23, and a lockup clutch 24. The pump 21 is connected to the crankshaft 10 of the engine 1, and the turbine 22 is connected to a carrier 41 of the planetary gear unit in the overdrive mechanism 40. In the overdrive mechanism 40, the planetary pinion 42 rotatably supported by the carrier 41 meshes with the sun gear 43 and the ring gear 44. A clutch C ₀ and a one-way clutch F ₀ are provided between the sun gear 43 and the carrier 41, and a brake B ₀ is provided between the sun gear 43 and the housing Hu.
Is provided. The underdrive mechanism 60 is provided with two rows of front and gear sides as a planetary gear unit. This planetary gear device includes a sun gear 61, ring gears 62 and 63, planetary pinions 64 and 65, and carriers 66 and 67, which are common to each other. The ring gear 44 of the overdrive mechanism 40 is connected to the ring gear 62 via the clutch C ₁ .
A clutch C ₂ is provided between the ring gear 44 and the sun gear 61. Further, the carrier 66
Is connected to the ring gear 63, and the carrier 66 and the ring gear 63 are connected to the output shaft 70. On the other hand, between the carrier 67 and the housing Hu,
A brake B ₃ and a one-way clutch F ₂ are provided, and further, between the sun gear 61 and the housing Hu,
The brake B ₂ is provided via the one-way clutch F ₁ .
A brake B ₁ is provided between the sun gear 61 and the housing Hu. This automatic transmission is provided with the transmission section as described above, and inputs signals from the throttle sensor 100 for detecting the throttle opening that reflects the load state of the engine 1 and the vehicle speed sensor 102 for detecting the vehicle speed. By means of the central processing unit (ECU) 104, the electromagnetic solenoid valves S _{1 to} S ₃ (for shift valves) and S _L (for rock up clutch) in the hydraulic control circuit 106 are set in accordance with a preset shift pattern. ) Is driven and controlled, and the engagement of the clutches, brakes, etc. is combined as shown in FIG. 3 to perform gear shift control. In FIG. 3, the mark "O" indicates the engaged state, and the mark "X" indicates the engaged state only when the engine brake is used. In FIG. 2, reference numeral 110 is a shift position sensor, which detects a position such as N (neutral), D (drive), R (reverse) operated by a driver, and 112 is a pattern select switch. Then E
(Economical traveling), P (power traveling), etc. are detected, 114 is a water temperature sensor for detecting the engine cooling water temperature, 116 is a foot brake, and 118 is a side brake operation. Brake switches are shown respectively. Next, FIG. 1 shows a main part in the hydraulic control circuit 106. In the figure, 10 is an oil pan and 12 is the oil pan 1.
An oil pump for pumping the oil in 0 to generate a basic hydraulic pressure, and 14 for adjusting the basic hydraulic pressure generated by the oil pump 12 to generate a line pressure according to the throttle opening or the like. This is a prime meter reguulator valve. 16 is a secondary regulator valve,
Reference numeral 18 is a throttle valve for generating a hydraulic pressure proportional to the opening degree of the throttle valve, 30 is a shift valve, and 32 is a shift valve.
Is a governor valve, 33 is a manual valve, and 34
Is a friction engagement device. The slot valve 18 includes seven lands 18A-1
Equipped with 8G. The slot pressure Pth of the slot pressure oil passage 50 is fed back and applied to the lower surface of the land 18B and the upper surface of 18C via the port 18X. In this feed back oil passage, the Olifis 36,
A solenoid valve 38 is provided, and the solenoid valve 38 is controlled by the switch 26 which is turned on when the engine exhaust brake is applied. Reference numeral 39 is a battery, and the switch 26 will be described in detail later. Also, since the functions of each valve are the same as the conventional ones, the explanation of the basic operation of each valve is omitted here, and the throttle pressure (line pressure control hydraulic pressure) is increased when the engine exhaust brake is applied. The control will be described in detail. The increase of the throttle oil pressure is performed as follows. When the exhaust brake works, the switch 26 turns ON,
Since the solenoid valve 38 opens the drain oil passage 38A, the oil pressure in the throttle pressure oil passage 50 (52) is drained, and the action of the slot oil pressure applied to the lands 18B and 18C of the slot valve 18 is released. The balance equation of the throttle valve 18 is as follows.
In the formula, B, C, and D are land 18
Areas of B, 18C and 18D (B <C <D), Pth is a slot pressure, and K ₁ and K ₂ are loads of the springs 18H and 18I. When switch 26 ON (exhaust brake ON): Pth (DC) + K ₁ = K ₂ (1) Pth = (K ₂ -K ₁ ) / (D-C) (2) Switch 26 OFF (exhaust brake OFF) ) when: Pth (D-C) + Pth (C-B) + K 1 = K 2 ......... (3) Pth = (K 2 -K 1) / (D-B) ... (4) Surotsutorubarubu 18 As is well known, by a slot cam (not shown) according to the slot opening, the spool 18J is pushed upward as the slot opening is larger, and the slot pressure becomes higher.
From the expressions (2) and (4), it is understood that since DC is less than DB, the throttle pressure Pth is correspondingly increased when the engine exhaust brake is actuated. Next, the balance type of the primary regulator valve 14 will be shown. The line pressure _{P L,} land 14L, 14M, 14
Q area, respectively L, M, Q, when the load of the spring 14R and _{K 3, P L (L-} M) = Pth × Q + K 3 ... (5) P L = Q / (L-M) · Pth + K 3 / (LM) ... (6) As a result, the line pressure becomes as shown in the above equation (6), and the line pressure is adjusted higher than the conventional one by the amount that the slot pressure Pth is higher, and therefore the friction engagement is performed. The hydraulic pressure acting on the device 34 will be set higher. The higher the hydraulic pressure acting on the friction engagement device, the shorter the engagement can be completed, that is, the time during which the two friction plate elements slide on each other can be shortened, and the durability is correspondingly reduced. You will be able to improve. The switch 26 is turned on and off by a configuration as shown in FIG. FIG. 4 shows a relay computer 200 in which various signals are input to the engine exhaust brake.
It is shown that it is operated by. In addition to the switches such as the clutch switch 202, the accelerator switch 204, the neutral switch 206, etc., the relay computer 200 has a vehicle speed signal 102 for the main switch 210.
Is entered together with. This relay computer 200
When it is determined by these inputs that the engine exhaust brake should be activated, the switch outputs a predetermined signal to the fuel control motor 212 and the magnetic valve 214 and turns on the switch 26. In the engine exhaust brake, a negative pressure is supplied from the vacuum tank 216 to the vacuum cylinder 218 via the magnetic valve 214, and the negative pressure causes the vacuum cylinder 218 to move, which causes the exhaust pipe 22 to move.
The exhaust retarder 222 provided in the middle of 0 blocks the flow of the air in the exhaust pipe 220 to be in an operating state. In the above embodiment, the increase of the slott oil pressure was adopted as the means for increasing the oil pressure for line pressure control, but in the present invention, the target oil pressure when increasing the oil pressure for line pressure control, Alternatively, the means for increasing the oil pressure is not limited, and, for example, the throttle hydraulic pressure may be adopted as the target oil pressure, or the duty control may be adopted as the increasing means.

【The invention's effect】

As described above, according to the present invention, the hydraulic pressure applied to the friction engagement device can be increased only when the engine exhaust brake is operating, and the fuel consumption during normal traveling,
Alternatively, it is possible to obtain an excellent effect that it is possible to prevent the durability of the friction engagement device from being deteriorated while maintaining the gear shifting feeling excellent.

[Brief description of drawings]

FIG. 1 is a main part hydraulic circuit diagram showing an embodiment of a hydraulic control device for an automatic transmission according to the present invention, and FIG. 2 is an overall schematic skeleton diagram of an automatic transmission to which the above embodiment is applied. FIG. 4 is a diagram showing an engaged / combined state of each friction engagement device in the automatic transmission, and FIG. 4 is a diagram showing a configuration for operating an engine exhaust brake. 14 ... Primary regulator valve, 18 ... Slot valve, 26 ... (for detecting engine exhaust brake operation) switch, 50, 52 ... Slot pressure oil passage, 200 ... (for engine exhaust brake operation) relay Computer.

Claims (1)

[Claims] 1. A hydraulic control device for an automatic transmission of a vehicle having a function capable of operating an engine exhaust brake, wherein a means for detecting whether or not the engine exhaust brake is in operation, and an engine exhaust brake in operation And a means for increasing the line pressure control hydraulic pressure of the hydraulic pressure control device at the time of, and a hydraulic pressure control device for the automatic transmission, comprising: