JPH0721954Y2 - Automatic transmission oil cooler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an oil cooling device for an automatic transmission, and more particularly, to preventing the temperature of a friction engagement portion of a speed change clutch from rising excessively. The present invention relates to an oil cooling device having improved reliability.

[Prior Art] Generally, in an automatic transmission, various hydraulic actuation systems such as a clutch and a piston are operated, torque transmission between a pump and a turbine of a torque converter is mediated, and friction engagement such as a speed change clutch and a brake is performed. Oil is needed to cool the parts or to lubricate parts that require lubrication, and such oil is supplied from the oil pump to each oil required part via the pressure control valve. ing.
Since the temperature of the oil flowing through each oil required portion is raised by frictional heat or the like, an oil cooler for cooling such oil is provided, but the temperature rise of the oil in the torque converter is particularly large. The oil cooler is usually provided downstream of the torque converter (see, for example, JP-A-60-166888).

By the way, a speed change clutch (the same applies to a brake) used in an automatic transmission causes a difference in speed between a driving side and a driven side at the time of shifting by frictionally engaging a paper friction member attached to each of them. Since the heat is absorbed, frictional heat is generated at the time of gear shifting, but there is a problem that the durability of the gear shifting clutch is reduced if the temperature of the friction engagement portion of the gear shifting clutch rises excessively. Therefore, as described above, the cooling oil is supplied to the friction engagement portion of the speed change clutch. Then, in order to effectively cool the friction engagement portion,
Cooling oil must penetrate into the porous space inside the paper friction member, but in such a case, the oil inside the paper friction member first oozes out, and then the space inside the paper friction member is exposed to the outside. The phenomenon that the oil penetrates from there occurs. Therefore, even if the flow rate of the cooling oil is increased, the amount of oil that penetrates into the paper friction member cannot be increased so much. Therefore, in order to effectively cool the friction engagement portion, it is necessary to make the temperature of the cooling oil as low as possible.

Therefore, the shift clutch cooling system is generally arranged downstream of the oil cooler. In other words, most of the oil discharged from the oil pump is torque converter → oil cooler →
It will flow in the order of the speed change clutch cooling system. In addition,
Oil is supplied to various hydraulic operating systems through another oil supply passage branched from an oil supply passage on the upstream side of the torque converter.

[Problems to be solved by the invention] However, at high engine speed, the oil flow in the torque converter becomes violent and the temperature of the oil rises significantly due to friction. Even if cooled, the oil cannot be cooled sufficiently. For this reason, the temperature of the oil supplied to the speed change clutch cooling system becomes high, and if the speed change operation is performed at such time, the temperature of the friction engagement portion of the speed change clutch excessively rises and the life of the speed change clutch is shortened. There was such a problem.

The present invention has been made in view of the above problems of the prior art, and even when the temperature of the oil flowing out from the torque converter is significantly increased at the time of high rotation, the temperature of the friction engagement portion of the speed change clutch is An object of the present invention is to provide an oil cooling device for an automatic transmission that can effectively prevent an excessive rise and improve the reliability of a shift clutch.

[Means for Solving the Problem] In an ordinary oil pump, the discharge amount increases almost proportionally as the engine speed increases. It is released to the pan so that the oil discharge amount does not exceed the upper limit value. However, the relief oil released to the oil pan in this way has a low temperature because it does not pass through the oil required portion. Therefore, when the relief oil is combined with the oil flowing out from the torque converter at the time of high rotation, the temperature of the oil flowing into the oil cooler can be lowered.

In order to achieve the above object, the present invention focuses on such a fact, and an oil pump that supplies oil to each oil required portion and an oil cooler that cools the oil whose temperature is raised in the oil required portion. In an oil cooling device for an automatic transmission provided with, a control valve, a torque converter, an oil cooler, and a speed change clutch are provided in series in an oil supply passage downstream of an oil pump from the upstream side. , The relief oil of the oil pump bypasses the torque converter and can be directly introduced into the oil cooler, and when the oil temperature is high, the relief oil is introduced into the oil cooler through the relief oil introduction passage. And a relief oil control means for controlling the oil cooling of the automatic transmission. To provide a location.

According to the present invention, when the temperature of the oil flowing out from the oil cooler becomes high at the time of high speed rotation, the low temperature relief oil discharged from the oil pump passes through the relief oil introduction passage. , Bypasses the torque converter and is introduced into the oil cooler. For this reason, the temperature of the oil flowing into the oil cooler decreases, and the temperature of the oil flowing out of the oil cooler accordingly decreases. Therefore, the temperature of the oil supplied to the shift clutch is lowered, the temperature of the friction engagement portion of the shift clutch is prevented from excessively rising, and the reliability of the shift clutch is improved.

On the other hand, when the temperature of the oil flowing out from the oil cooler is originally low, the relief oil is released to the outside (for example, the oil pan), the load on the oil pump is reduced, and the torque loss is reduced.

[Examples] Examples of the present invention will be specifically described below.

First Embodiment As shown in FIG. 1, in the oil supply system FE of the automatic transmission, the oil in the oil pan 1 is sucked into the oil pump 3 through the strainer 2 and then the oil pump 3
Is discharged to the main oil supply passage L ₁ . The oil pump 3 is an ordinary oil pump of the involute gear type, for example, and discharges oil at a flow rate substantially proportional to the engine speed.

When the engine speed increases and the discharge amount of the oil pump 3 increases more than necessary, an oil relief passage L ₂ for returning excess oil to the oil pan 1 branches from the main oil supply passage L _1. Is provided. This is the oil relief passage L ₂ hydraulic control valve 4 is interposed, the hydraulic control valve 4 is opened when the oil pressure is high in the oil pump 3 downstream of the main oil supply passage L _1, excess oil oil relief passage Return to oil pan 1 through L ₂ ,
The flow rate of oil supplied to the oil-required portion is maintained below a predetermined value.

In this way, the oil discharged from the oil pump 3 to the main oil supply passage L ₁ and having the flow rate adjusted by the hydraulic pressure adjusting valve 4 is first introduced into the control valve 5 for gear shift control. Then, a part of this oil is supplied as hydraulic oil to various hydraulic operating systems 6 such as a clutch and a piston through the hydraulic operating system oil supply passage L ₃ . The oil discharged from these hydraulic operating systems 6 is returned to the oil pan 1.

Further, the main oil supply passage L ₁ downstream of the control valve 5 sequentially cools the torque converter 7 that torque-converts the torque on the engine side to the transmission side and transmits the torque, and the oil whose temperature has been raised in the torque converter 7. The oil cooler 8 and the friction engagement portion of the speed change clutch 9 are connected in series. Then, the oil that has flowed into the control valve 5 and has not been supplied to the hydraulic operating system 6 side is returned to the oil pan 1 after flowing through the torque converter 7, the oil cooler 8 and the speed change clutch 9 in series. ing.

By the way, a three-way valve 15 driven and controlled by a three-way valve drive circuit 14 is provided in the oil relief passage L ₂ downstream of the hydraulic pressure adjusting valve 4, and the first connection portion 15 a of the three-way valve 15 is provided.
Is connected to the oil relief passage L ₂ on the upstream side, the second connection portion 15b is connected to the oil relief passage L ₂ on the downstream side, and the other end of the third connection portion 15c is located downstream of the torque converter 7. Further, the relief oil introduction passage L ₄ connected to the main oil supply passage L ₁ upstream of the oil cooler 8 is connected.

An oil temperature sensor 11 is provided in the main oil supply passage L ₁ downstream of the oil cooler 8 and upstream of the speed change clutch 9.
The value detected by the oil temperature sensor 11 (hereinafter referred to as the oil cooler outlet oil temperature) is input to the determination circuit 13. This determination circuit 13 compares the oil cooler outlet oil temperature detected by the oil temperature sensor 11 with the reference oil temperature applied from the reference value setting means 12, and when the oil cooler outlet oil temperature is higher than the reference oil temperature. , A signal indicating this (high signal)
Is output to the three-way valve drive circuit 14, and when the oil cooler outlet oil temperature is equal to or lower than the reference oil temperature, a signal (low signal) indicating this is output to the three-way valve drive circuit 14. The reference oil temperature is set to such a value that if the oil cooler outlet oil temperature is higher than this, cooling of the friction engagement portion of the speed change clutch 9 becomes insufficient and the temperature of the speed change clutch 9 rises excessively. There is.

Then, when the high signal is input from the determination circuit 13, the three-way valve drive circuit 14 includes the first connecting portion 15a and the third connecting portion 1
Set the three-way valve 15 so that it is connected to 5c. At this time, the oil flowing from the main oil supply passage L ₁ into the oil relief passage L ₂ is introduced into the main oil supply passage L ₁ upstream of the oil cooler 8 through the relief oil introduction passage L ₄ . On the other hand, when the low signal is input, the three-way valve drive circuit 14 sets the three-way valve 15 so that the first connecting portion 15a and the second connecting portion 15b are connected. At this time, the oil flowing from the main oil supply passage L ₁ into the oil relief passage L ₂ is released to the oil pan 1.

In the above structure, when the oil temperature at the outlet of the oil cooler is higher than the reference oil temperature, that is, when the temperature of the shift clutch 9 may excessively rise during shifting, the relief oil released to the oil pan 1 under normal conditions is relieved. It is introduced into the main oil supply passage L ₁ upstream of the oil cooler 8 through the oil introduction passage L ₄ .

The polygonal line G ₁ in FIG. 2 indicates the oil temperature of the oil supply system from the upstream side of the torque converter 7 to the downstream side of the speed change clutch 9 when the relief oil is introduced upstream of the oil cooler 8 as described above. The polygonal line G ₂ shows the oil temperature when the relief oil is not introduced upstream of the oil cooler 8. As is clear from FIG. 2, according to the present proposal (the polygonal line G ₁ ), the oil temperature decreases stepwise at the point B where the relief oil is introduced, and the oil temperature on the downstream side of this is the conventional oil supply system. It is much lower than (line G ₂ ). For this reason,
Even during a gear shift, the temperature increase of the gear shift clutch 9 can be suppressed below the limit value, and the reliability of the gear shift clutch 9 can be improved.

On the other hand, the relief oil is released to the oil pan 1 when the oil cooler outlet oil temperature is equal to or lower than the reference oil temperature, that is, when there is no fear that the temperature of the shift clutch 9 excessively increases even during shifting. At this time, since the load on the oil pump 3 is reduced, the power consumption of the oil pump 3 can be suppressed to the necessary minimum, and the torque loss is reduced.

<Second Embodiment> Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 3 to 7. The same components as those of the first embodiment shown in FIG. In order to avoid this, the same numbers as in the first embodiment are assigned and the description thereof is omitted.

As shown in FIG. 3, in the second embodiment, the oil pump 21
Is a vane type variable displacement pump. As will be described later, the variable displacement oil pump 21 basically operates by the discharge amount adjusting valve 22 so that the discharge amount is proportional to the engine speed when the engine speed is equal to or lower than a predetermined value. Although it rises, if the engine speed exceeds a specified value, the oil pump
The hydraulic pressure is applied to 21, and this hydraulic pressure reduces the discharge capacity per one rotation of the pump, so that the discharge amount (rotation number x discharge capacity) becomes constant. A three-way valve 23 is provided in the flow control port 24, and the first connection portion 23a of the three-way valve 23 has an upstream flow control port 24.
Is connected to the second connection portion 23b, and the downstream flow control port 24 is connected to the second connection portion 23b. The third connection portion 23c has a hydraulic release passage whose other end communicates with the drain passage 25 of the discharge control valve 22. 26 is connected.

As shown in FIG. 5, the oil pump 21 has a cam ring 26.
Inside, a rotor 28 having a plurality of vanes 27 is rotationally driven, and accordingly, oil is sucked from the suction port 31,
The basic structure is such that oil is discharged from the discharge port 32.

Then, the cam ring 26 can be displaced in the direction of the double-headed arrow PQ with the pivot roller 33 as a fulcrum to adjust the eccentricity between the cam ring 26 and the roller 28. When the cam ring 26 is located on the P side, the eccentricity is increased, and accordingly, the discharge capacity per one rotation of the rotor is increased. On the other hand, when the cam ring 26 is positioned on the Q side, the eccentricity is decreased and one rotation of the rotor The discharge capacity per hit becomes smaller. The cam ring 26 is pressed by the first spring 34 in the P direction, and in the Q direction from the main oil supply passage L ₁ (see FIG. 3) to the flow control port.
Pressed by the hydraulic pressure introduced to the L part 35 through 24,
Positioning is performed by the balance of these two pressing forces, and the eccentricity of the cam ring 26, that is, the discharge capacity per one rotation of the rotor is determined.

The hydraulic pressure introduced into the L portion 35 via the flow rate control port 24 is controlled by the discharge amount control valve 22.

As shown in FIG. 6, the inside of the discharge amount control valve 22 is a spool.
37 and is provided with the second spring 38, the spool 37 when the oil pressure in the main oil supply passage L ₁ is low is moved to the S side by the biasing force of the second spring 38, this time the main oil supply passage L ₁ Oil pressure does not act on the flow control port 24. In such a state, the discharge amount of the oil pump 21 is proportional to the engine speed.

On the other hand, as shown in FIG. 7, when the oil pressure in the main oil supply passage L ₁ becomes high, this oil pressure causes the spool 37 to move to the T position.
The hydraulic pressure in the main oil supply passage L ₁ is introduced into the flow rate control port 24 through the communication hole 41 in accordance with the amount of movement. At this time, hydraulic pressure is introduced into the L portion 35, so that the eccentricity between the cam ring 26 and the rotor 28 becomes small, and the discharge capacity per one rotation of the rotor decreases. At this time, the discharge amount of the oil pump 21 (rotor speed × discharge capacity) becomes constant.

As shown in FIG. 3 again, when the oil cooler outlet oil temperature is higher than the reference oil temperature in the above configuration, that is, when the temperature of the shift clutch 9 may excessively rise during shifting, the three-way valve drive circuit 14 First of the three-way valve 23
The connecting portion 23a and the third connecting portion 23c are connected, and the L portion 35 (fifth
The hydraulic pressure in the main oil supply passage L ₁ is no longer introduced into (see the figure). Therefore, the cam ring 26 remains maximally eccentric, and the discharge amount of the oil pump 21 increases in proportion to the engine speed even in the high speed range. For this reason, the oil flow rate in the main oil supply passage L ₁ is significantly increased, and the increase in the oil temperature in the torque converter 7 is small, and therefore the oil temperature in the torque converter 7 to the speed change clutch 9 is the same as that in FIG. As shown by the polygonal line G ₃ , the oil temperature in the conventional oil supply system is significantly lower than the oil temperature (polygonal line G ₄ ). Therefore, the temperature increase of the shift clutch 9 can be suppressed to the limit value or less even during shifting, and the reliability of the shift clutch 9 can be improved.

On the other hand, when the oil cooler outlet oil temperature is equal to or lower than the reference oil temperature, that is, when there is no fear that the temperature of the shift clutch 9 excessively increases during shifting, the three-way valve drive circuit 14
The first connecting portion 23a and the second connecting portion 23b of the three-way valve 23 are connected, and the L portion 35 (see FIG. 5) has a main oil supply passage L ₁
The internal hydraulic pressure is introduced. In this case, the discharge amount of the oil pump 21 becomes constant when the engine speed exceeds a predetermined value.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an oil cooling device for an automatic transmission showing a first embodiment of the present invention. FIG. 2 is a diagram showing the oil temperature of each part when the relief oil is introduced into the oil cooler in the oil cooling device shown in FIG. FIG. 3 is a system configuration diagram of an oil cooling device for an automatic transmission showing a second embodiment of the present invention. FIG. 4 is a diagram showing the oil temperature of each part in the oil cooling device shown in FIG. 3 when the hydraulic pressure supply to the L part of the variable displacement oil pump is stopped. FIG. 5 is a front explanatory view of a variable displacement oil pump used in the oil cooling device shown in FIG. FIG. 6 and FIG. 7 are diagrams showing the operating state of the discharge amount control valve of the oil pump shown in FIG. 5, respectively. FE …… Oil supply system, L ₁ …… Main oil supply passage,
L ₂ …… Oil relief passage, L ₄ …… Relief oil introduction passage, 3 …… Oil pump, 4 …… Hydraulic adjustment valve, 5 ……
Control valve, 6 ... Hydraulic system, 7 ... Torque converter, 8 ... Oil cooler, 9 ... Shift clutch, 13 ... Judgment circuit, 14 ... Three-way valve drive circuit, 15 ... Three-way valve, 21 ... … Oil pump, 22… Discharge control valve, 23…
… A three-way valve.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. An oil cooling device for an automatic transmission, comprising: an oil pump for supplying oil to each oil required portion; and an oil cooler for cooling oil whose temperature has been raised in the oil required portion. A control valve, a torque converter, an oil cooler, and a speed change clutch are installed in series in the oil supply passage from the upstream side, and relief oil of the oil pump bypasses the torque converter and And a relief oil control means for introducing relief oil into the oil cooler through the relief oil introduction passage when the temperature of the oil is high. Oil cooler for automatic transmission.