JPS60260767A - Oil cooling device of automatic speed change gear - Google Patents

Abstract

PURPOSE:To prevent air from being sucked in an oil pump by providing an oil path extending to an oil reserver, which branches from an oil path for conducting oil of a fluid torque converter to an oil cooler, and opening the oil path only when the temperature of oil is low. CONSTITUTION:At the time of starting an engine, an oil pump 10 is driven to let air in a fluid torque converter 42 flow out from a port 40 or an orifice 58 to an oil path 56 through a port 38. When oil temperature is high, a temperature response valve 72 closes an oil path 78. As the viscosity of oil is small, oil pressure in the oil path 56 does not increase, so that a cooler by-pass valve 64 does not open an oil path 66. Accordingly, air is not sucked in the oil pump 10 through the oil path 62. On the other hand, when oil temperature is low, the temperature response valve 72 opens the oil path 70. Therefore, the cooler by- pass valve 64 will not be opened, so that air is not sucked in the oil pump 10 through the oil path 62.

Description

[Detailed description of the invention] Technical field The present invention relates to an oil cooling device for an automatic transmission.

In prior art automatic transmissions, in order to cool the oil used therein, the oil from the fluid torque converter is guided through a cooler hose to an oil cooler (2) and from the oil cooler back to an oil reservoir. Further, in order to prevent damage to the cooler hose, a cooler bypass valve is provided which opens and discharges oil when the oil pressure of the cooler hose exceeds a predetermined value. Furthermore, if the discharged oil from the cooler bypass valve is returned directly to the oil reservoir, air will be mixed into the oil and the oil level in the oil reservoir will rise. improves the inhalation efficiency.

However, when the engine is stopped, the oil in the fluid torque converter leaks out, and when the engine is restarted, the air accumulated in the fluid torque converter heads toward the oil cooler. is low and the resistance of the cooler hose line is low, so the air passes through as is, but when the oil temperature is low, the viscosity of the oil is high and the resistance of the cooler hose line is large, so the cooler bypass valve opens. There is a possibility that the oil pump will suck in air (3) and the line pressure PA' will drop. A decrease in the line pressure Pl impairs the accuracy of the dividing part of the hydraulic control device, and may also cause a situation where the vehicle cannot start.

JP-A-57-12719 discloses a cooling device that guides oil to a bypass line instead of an oil cooler when the oil temperature is low, but air in the bypass line is sucked into the oil pump and the line pressure increases. Preventing Pl from decreasing]
There is no mention of any means of doing so.

OBJECTS An object of the present invention is to provide an oil cooling device for an automatic transmission that prevents air from being drawn into an oil pump via a cooler bypass valve when the oil is at a low temperature.

Structure To achieve this object, the present invention provides a first oil passage that leads the oil of the fluid torque converter to the oil cooler, and a first oil passage that branches from the first oil passage and leads to the suction (4) side of the oil pump. In an oil cooling system for an automatic transmission, the oil cooling system for an automatic transmission includes a second oil passage and a cooler bypass valve that opens the second oil passage when the oil pressure in the first oil passage reaches a predetermined value or more. and a temperature-responsive valve that opens the third oil passage when the oil temperature is low and closes the third oil passage when the oil temperature is high.

Function and Effect When the oil temperature is high, the temperature-sensitive valve is closed;
In addition, since the viscosity of the oil is low and the pipe resistance of the first oil path is low, the pressure in the first oil path is therefore low, so the cooler bypass valve does not open and the air in the fluid torque converter flows through the cooler bypass valve. It is not guided to the oil pump, but flows directly through the oil cooler.

(5) When the oil temperature is low, the viscosity of the oil is high, so
The cooler bypass valve may open and fluid torque converter air may be directed from the cooler bypass valve toward the oil pump. However, in the present invention, a temperature sensitive valve uses a third oil passage to prevent air within the fluid torque converter from being directed to the oil pump.

In this way, it is possible to prevent air from being sucked into the oil pump due to the opening of the cooler bypass valve when the oil temperature is low, thereby preventing a drop in line pressure.

Preferably, the temperature-responsive valve has a valve body that opens and closes the third oil passage by changing the shape of the shape memory alloy, or the temperature-responsive valve opens and closes the third oil passage in relation to the output of the temperature sensor. It is a solenoid valve that

Example The present invention will be described with reference to the embodiments shown in the drawings.

In FIG. 1, the oil pump lO is connected to the oil reservoir 1.
2 is sucked in through the strepana 14 and the suction oil passage 16, and is discharged to the line pressure oil passage +8 (6). The line pressure Pl of the primary regulator valve 20 pressure oil passage 18 is set to a value corresponding to the intake throttle opening.・Other hydraulic control circuits 24 are line pressure oil passages 1
8 to line pressure P7! be supplied with. The secondary regulator valve 26 has a secondary hydraulic oil passage 22 and a lubricating oil passage 28.
The connection with the secondary hydraulic oil passage 22 is controlled in relation to the intake throttle opening, and the secondary oil pressure of the secondary hydraulic oil passage 22 is set to a value related to the intake throttle opening.

The relay valve 30 connects the boat 32, drains 3 and 4, and other boats 3 connected to the secondary hydraulic oil line 22.
6, 38, 40, and in the on position of the lockup connects the boat 38 to the boat 32 and the boat 36 to the drain 34, and in the off position of the lockup connects the boat 36 to the boat 32 and the boat 38 to the boat 40. . A fluid torque converter 42 is provided between the crankshaft of the engine and a gear transmission section, and a lock-up clutch 44 is provided in parallel with the fluid torque converter. Boat 46 is connected to boat 38 via oil line 48, and boat 50 is connected to boat 36 via oil line 52. When relay valve 30 is in the on position, boat 32
The secondary hydraulic pressure of the boat 38, the oil line 48, and the boat 46
is connected to the fluid torque converter 42 via the
Oil in boat 50 is discharged from drain 34 via oil passage 52 and boat 36 . As a result, the lock-up clutch 44 becomes engaged.

When the relay valve 30 is in the OFF position, the secondary hydraulic pressure of the boat 32 is applied to the boat 36, the oil line 52, the boat 50, the fluid torque converter 42, the boat 46, the oil line 48, and the boat 3.
8, and Po 1-40. As a result, the lock-up clutch 44 is released and torque is transmitted through the fluid 1-to-lux converter 42.

Oil cooler 54 is connected to boat 40 via oil passage 56 , and oil passage 56 is connected to oil passage 48 via orifice 58 . The oil that passes through the oil cooler 54 (8) is oil FI! 560 and is returned to the oil reservoir]2. The oil passage 62 branches from the oil passage 56 and becomes the suction oil passage 1.
6 and the valve body 66 of the cooler bypass valve 64 reaches the suction oil path 16 of the pump lO when the oil pressure in the oil path 56 exceeds a predetermined value. This is because air gets mixed into the oil and raises the oil level, and also because air is returned to the suction oil path 16 to increase the suction efficiency of the oil pump 10.

The oil passage 70 branches from the oil passage 62 on the fluid torque converter 42 side and reaches the oil reservoir 12 . The temperature-responsive valve 70 opens the oil passage 70 when the oil temperature is less than a predetermined value, and closes the oil passage 70 when the oil temperature is equal to or higher than the predetermined value.

FIG. 2 shows a first embodiment of the temperature responsive valve 72. As shown in FIG. This temperature-responsive valve 72a is connected to a separation plate 80 that defines the oil passage 56.
The valve body 84 has a boat 82 formed in the shape of a cylindrical shape, a valve body 84 that opens and closes the boat 82, and a shape memory alloy 86 of a coil shape that comes into contact with the rear end surface of the valve body 84 (9). The shape memory alloy 86 assumes a contracted coil shape at low temperatures and an expanded coil shape at high temperatures. Therefore, when the oil is at a low temperature, the oil passage 70 is opened, and when the oil is at a high temperature, the oil passage 70 is closed.

FIG. 3 shows another embodiment of the temperature responsive valve 72. This temperature-responsive valve 72b has a valve body 90 that opens and closes the boat 82.
, a spring 92 that urges the valve body 90 toward the boat 82, and a solenoid 94 that attracts the valve body 90. A temperature switch 96 is provided within the oil reservoir 12,
It opens when the oil is hot and closes when the oil is cold.

Temperature switch 96 is grounded at one end and connected to solenoid 94 via power supply 98 at the other end.
connected to. Therefore, when the oil is high temperature, the solenoid 90 is de-energized, and the valve body 90 closes the boat 82 by the spring 92, so the oil passage 70 is closed, and when the oil is low temperature, the solenoid 90 is energized. In state (10), the valve body 90 is attracted against the spring 92 and opens the boat 82, so that the oil passage 70 is opened.

Returning to FIG. 1, the overall operation will be explained.

During the engine stop J1, the oil pump 10 is also in a stopped state, so the oil in the fluid torque converter 42 flows out and air accumulates in the fluid torque converter 42.

At the next start, the oil pump 10 is driven and the air in the fluid torque converter 42 is pumped through the boat 38 to the boat 4.
0 or from the orifice 58 to the oil passage 56.

When the oil is at high temperature, the temperature-responsive valve 72 closes the oil passage 70, but since the viscosity of the oil is low, the oil pressure in the oil passage 56 does not increase, and the cooler bypass valve 66 does not open the oil passage 66. Therefore, air is prevented from being sucked into the oil pump 10 through the oil passage 62, and a decrease in line pressure Pl due to air suction is prevented.

When the oil is at a low temperature, the temperature-responsive valve 72 opens the oil passage 70. If the temperature-responsive valve 72 is closed, the viscosity of the oil is high, so the resistance of the oil passage 56 increases, and the oil passage 56
The oil pressure also increases, causing the cooler bypass valve 66 to open, but since the temperature-responsive valve 72 is open, the cooler bypass valve 66 is prevented from opening. Therefore, air via the oil passage 62 is prevented from being sucked into the oil pump 10.

Although the present invention has been described with reference to embodiments, various modifications and changes may be made without departing from the spirit described in the claims.
It will be obvious to those skilled in the art that the invention may be practiced in modified forms.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing embodiments of a temperature-responsive valve. 10...Oil pump, 42...Fluid torque converter, 54...Oil cooler, 56, 62°70...
・Oil passage, 64...Cooler bypass valve, 72.72
a, 72b-m degree response valve. Figure 3 94 6

Claims (1)

[Claims] 1. A first oil passage that leads the oil of the fluid torque converter to the oil cooler, a second oil passage that branches from the first oil passage and leads to the suction side of the oil pump, and a first oil passage that leads to the oil cooler. In an oil cooling system for an automatic transmission, the oil cooling system for an automatic transmission includes a cooler bypass valve that opens a second oil passage when oil pressure in the oil passage exceeds a predetermined value. and a temperature-responsive valve that opens a third oil passage when the oil temperature is low and closes the third oil passage when the oil temperature is high. Device. 2. The oil cooling device according to claim 1, wherein the temperature-responsive valve has a valve body that opens and closes the third oil passage by (1) changing the shape of the shape memory alloy. . 3. The oil cooling device according to claim 1, wherein the temperature-responsive valve is a solenoid valve that opens and closes the third oil passage in relation to the output of the temperature sensor. 4. The branching point of the third oil passage from the first oil passage is closer to the fluid torque converter than the branching point of the second oil passage from the first oil passage. The oil cooling device according to any one of items 1 to 3.