JP3211365B2 - Fluid transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid transmission.

[0002]

2. Description of the Related Art Conventionally, in an automatic transmission, a torque generated by an engine is transmitted to a transmission via a fluid transmission, and the transmission performs a speed change to transmit the transmission to drive wheels. Among the fluid transmission devices, for example, a torque converter is a fluid that circulates inside, such as oil, as a torque converter,
Acting as a fluid coupling, it consists of a pump impeller, turbine runner, stator, one-way clutch and lock-up device.

[0003] That is, the rotation transmitted from the engine to the torque converter via the crankshaft is transmitted to the pump impeller via the front cover of the torque converter. And when the pump impeller rotates,
Oil in the torque converter circulates between the pump impeller, the turbine runner, and the stator by centrifugal force to rotate the turbine runner.

[0004] An input shaft of a transmission is connected to the turbine runner so that an output from a torque converter is transmitted to the transmission. The stator is provided between the pump impeller and the turbine runner. When the difference between the rotation speeds of the two is large, the stator converts the oil flow into a direction that assists the rotation of the pump impeller and increases the torque.

Further, the lock-up device has a lock-up piston which is attached to the turbine runner and slides, and which is fixed in the rotation direction. The lock-up piston is detachable from the front cover. It is arranged to be. Then, at the time of start, the lock-up piston is released from the front cover, and the torque generated by the engine is transmitted to the input shaft through the flow of oil, and is engaged with the front cover when the vehicle reaches the set speed, The torque generated by the engine is transmitted directly to the transmission.

Therefore, a lock-up relay valve is connected to the torque converter, and the lock-up device is disengaged by switching the lock-up relay valve. That is, in the torque converter, a lock-up release-side oil chamber is formed between the front cover and the lock-up piston, and a lock-up engagement-side oil chamber is formed between the lock-up piston and the pump impeller. The lock-up piston can be released by supplying oil to the up-release oil chamber, and the lock-up piston can be engaged by supplying oil to the lock-up engagement-side oil chamber.

However, recently, there has been provided a lock-up device in which slip control is performed between a front cover and a lock-up piston to continuously slide the lock-up piston to improve fuel efficiency. In this case, since the friction material provided on the lock-up piston slides on the front cover for a long period of time, the temperature of the friction material may increase and burns may occur. Therefore, at the position where the friction material of the lock-up piston is fixed, a hole communicating between the lock-up release side oil chamber and the lock-up engagement side oil chamber is formed, and communicates with the hole. There has been provided a lockup device in which a groove extending radially outward is formed in a friction material. In this case, when the lock-up piston is engaged, oil in the lock-up engagement side oil chamber is prevented from leaking into the lock-up release side oil chamber, and oil supplied from the hole is circulated through the groove. By doing so, the friction material is cooled (see Japanese Patent Application Laid-Open No. Hei 3-209045).

[0008]

However, in the conventional hydraulic power transmission device, the lock-up piston rotates at a high speed when engaged with the front cover or when the lock-up piston is slid under slip control. The oil supplied from the lock-up engagement side oil chamber through the hole is
Without being sufficiently supplied to the surface of the friction material, it flows out radially outward along the groove as it is.

Therefore, the periphery of the groove can be cooled, but the entire friction material cannot be cooled. The present invention solves the problems of the conventional fluid transmission device and sufficiently cools the entire friction material when the lock-up piston of the lock-up device is engaged with or slides on the front cover. It is an object of the present invention to provide a fluid transmission device that can perform the following.

[0010]

For this purpose, in the fluid transmission of the present invention, a front cover to which torque generated by an engine is transmitted, a pump impeller that rotates integrally with the front cover, A turbine runner that receives torque from the pump impeller by the flow of oil and transmits the torque to an output shaft, and a lock-up release-side oil chamber attached to the turbine runner and facing the front cover, A lock-up piston formed by partitioning a lock-up engagement side oil chamber on the opposite side, and selectively engaging and disengaging and sliding with respect to the front cover; And a friction material fixed to the surface to be formed. A hole is formed in the lock-up piston at a position corresponding to the friction material, for communicating the lock-up release-side oil chamber and the lock-up engagement-side oil chamber.

In another fluid transmission of the present invention, the holes are formed at a plurality of positions in the circumferential direction of the lock-up piston and are distributed at various positions in the radial direction.

[0012]

According to the present invention, as described above, in the fluid transmission device, the front cover to which the torque generated by the engine is transmitted, and the pump impeller that rotates integrally with the front cover. A turbine runner that receives torque from the pump impeller by a circulating oil flow and transmits the torque to an output shaft, and a lock-up release side oil chamber mounted on the turbine runner and facing the front cover. A lock-up piston formed by partitioning a lock-up engagement side oil chamber on the opposite side and selectively engaging and disengaging and sliding with respect to the front cover; and a lock-up piston in the front cover. And a friction material fixed to a surface facing the friction material. A hole is formed in the lock-up piston at a position corresponding to the friction material, for communicating the lock-up release-side oil chamber and the lock-up engagement-side oil chamber.

In this case, the lock-up piston is released from the front cover by supplying oil to the lock-up release side oil chamber, and the lock-up piston is released from the front cover by supplying oil to the lock-up engagement side oil chamber. When the slip control is performed, the lock-up piston and the front cover can be slid.

A friction material is fixed to a surface of the front cover facing the lock-up piston, and the lock-up release side oil chamber and the lock-up engagement side are located at positions of the lock-up piston corresponding to the friction material. A hole communicating with the oil chamber is formed. Therefore, while the lock-up piston is engaged or slid with the front cover, the oil in the lock-up engagement side oil chamber is supplied to the surface of the friction material, so that the entire friction material is removed. Cooling can be performed, and high-temperature oil staying in the vicinity of the friction material can be discharged.

When the lock-up piston slides relative to the friction material by the slip control, the friction material and the lock-up piston rotate relative to each other. Therefore, the oil supplied from the hole of the lock-up piston moves on the surface of the friction material with the relative rotation, and spreads over the entire friction material.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 4 is a sectional view of a fluid transmission device showing an embodiment of the present invention. In the figure, a torque converter 11 includes a power transmission case 12 that constitutes a case of the torque converter 11 and a fluid transmission unit 13 that transmits torque via oil in the power transmission case 12. A lock-up device 14 is provided between the fluid transmission units 13.

The power transmission case 12 includes a front cover 12a for accommodating the lock-up device 14, a rear cover 12b welded to the front cover 12a, and a sleeve 12c welded to the rear cover 12b. The front cover 12a is connected to a crankshaft of the engine via a drive plate (not shown). The sleeve 12c is rotatably supported by a partition between the engine and the transmission, and a rear end of the sleeve 12c is connected to an oil pump (not shown) provided in the partition.

The fluid transmission unit 13 includes a rear cover 12b
And a pump impeller 15 for flowing oil from the inner peripheral side to the outer peripheral side by centrifugal force by the rotation of the rear cover 12b. The pump impeller 15 is provided to face the pump impeller 15, and the pump impeller 15 is provided on the outer peripheral side. Receiving the shed oil,
The direction of oil flowing between the pump runner 16 and the inner circumferential side of each of the turbine runner 16 to which the rotation of the pump impeller 15 is transmitted by flowing again to the inner circumferential side is changed. And a stator 17 for increasing the torque transmitted to the turbine runner 16.

An outer race 18a of a one-way clutch 18 rotatable in only one direction is fixed to the inner periphery of the stator 17. The inner race 18b of the one-way clutch 18 is spline-fitted to the outer periphery of a fixed sleeve (not shown) connected to the oil pump. Further, a turbine flange 16a supporting the turbine runner 16 is fixed to a turbine hub 20 by rivets 19, and the turbine hub 20 is an output shaft of the torque converter 11, which is rotatably supported on the inner periphery of the fixed sleeve. It is spline-fitted to the output shaft of the transmission and is fixed in the axial direction. An oil passage 21 communicating with the turbine hub 20 in the axial direction is formed in the turbine hub 20.

In the torque converter 11 configured as described above, the rotation transmitted from the engine to the torque converter 11 via the crankshaft is transmitted to the torque converter 11
Of the power transmission case 1
The power is transmitted to the pump impeller 15 fixed to the pump impeller 2. When the pump impeller 15 rotates, the oil in the torque converter 11 generates a flow that rotates around the shaft portion, and this flow is generated by centrifugal force.
Circulates between the turbine runner 16 and the stator 17.

When the pump impeller 15 has just started to start, ie, when it is stalled, the difference between the rotation speed of the pump impeller 15 and the rotation speed of the turbine runner 16 is large. The oil flows in a direction that hinders rotation of the pump impeller 15. In view of this, the stator 17 is provided between the pump impeller 15 and the turbine runner 16, and when the difference between the rotation speeds of the two is large, the flow of oil is reduced by the pump impeller 1.
5 is converted to a direction that helps rotation.

At this time, since the blades of the stator 17 receive the torque from the oil flow, the torque increases accordingly.
The torque received by the blades of the stator 17 from the oil flow is equal to the difference between the torque output from the turbine runner 16 and the torque input from the engine, and the difference between the rotation speed of the pump impeller 15 and the rotation speed of the turbine runner 16 is obtained. It decreases as the difference decreases.

This is because the oil hitting the front side of the blades of the stator 17 comes to hit the back side in reverse as the rotation speed of the turbine runner 16 increases.
To prevent the oil flow, the stator 1
If 7 is fixed to the fixed shaft, it becomes a hindrance, and the stator 17 itself consumes energy.

Therefore, a one-way clutch 18 that can rotate in only one direction is provided between the stator 17 and the fixed sleeve, and when the oil hits the back side of the stator 17 blades, that is, at the clutch point, the one-way clutch 18 It becomes free and the stator 17 can rotate freely. As described above, the torque converter 11 functions as a torque converter while the rotation speed of the turbine runner 16 is low. When the rotation speed of the turbine runner 16 increases and becomes substantially equal to the rotation speed of the pump impeller 15, the fluid However, the torque does not increase while acting as a fluid coupling, and merely transmits the rotation.Therefore, the transmitted torque is reduced by the loss due to oil agitation and the like. I will.

Therefore, when the speed of the vehicle reaches the set value, the lock-up device 14 is operated to directly transmit the rotation of the engine to the turbine hub 20 to improve the torque transmission efficiency. The lock-up device 14
The lock-up piston 22 includes an inner cylindrical portion 22a, an outer cylindrical portion 22b, and an annular plate portion 22c, and the inner cylindrical portion 22a of the lock-up piston 22 is provided.
Are externally slidably fitted to the outer peripheral portion of the turbine hub 20 via a seal ring 23 in the axial direction.

A damper mechanism 24 is provided between the lock-up piston 22 and the turbine hub 20.
The damper mechanism 24 includes a group of dampers 24a formed of compression coil springs, and a driven plate 24 including a first guide plate 24b and a second guide plate 24c that enclose the damper 24a and slidably hold in the circumferential direction.
d, the outer periphery of which is spline-fitted to the outer peripheral side cylindrical portion 22b, and the first guide plate 24b and the second guide plate 2
The drive plate 24f is slidably held in the circumferential direction between the drive plates 24f. The drive plate 24f
Is provided with a damper 24a inside, and the damper 2
4a is provided with a damper urging window for urging the 4a by sliding the driven plate 24d.

The first guide plate 24b is fixed to the turbine flange 16a of the turbine runner 16 by rivets 19. The first and second guide plates 24b and 24c are connected to each other by rivets 24g. Further, the front cover 12
A friction material 25 is fixed at a position corresponding to the annular plate portion 22c of the lock-up piston 22 on a.

The lock-up piston 22 has a lock-up releasing oil chamber 27 on the side facing the front cover 12a, and a lock-up engaging oil chamber 28 on the opposite side.
Is formed by partitioning. When the oil pressure in the lock-up release-side oil chamber 27 is higher than the oil pressure in the lock-up engagement-side oil chamber 28, the lock-up piston 22
And the friction material 25 does not engage with the lock-up piston 22.

When the oil pressure in the lock-up release side oil chamber 27 decreases and a predetermined pressure difference is generated with respect to the oil pressure in the lock-up engagement side oil chamber 28, the lock-up piston is caused by the pressure difference. 22 is the front cover 12
It moves toward a and is engaged with the friction material 25. In this state, the torque from the engine is directly transmitted to the turbine hub 20.
Will be transmitted to

Next, hydraulic oil supply means for supplying oil to the lock-up release side oil chamber 27 and the lock-up engagement side oil chamber 28 will be described. Hydraulic oil supply means passes through the output shaft of the torque converter 11 from the lock-up relay valve, and is formed in the thrust bearing 30 between the front cover 12a and the turbine hub 20 and between the front cover 12a and the turbine hub 20. A first oil passage system A communicating with the lock-up release side oil chamber 27 via the passage 31;
A second oil passage system B is provided which communicates with the lock-up engagement side oil chamber 28 via an oil passage 32 formed between the sleeve 12c and the one-way clutch 18 from the lock-up relay valve.

In the lock-up device 14 having the above-described configuration, if the lock-up relay valve is set so that the lock-up device 14 is in the lock-up off state, the oil is transmitted through the first oil passage system A to the power transmission case. The oil is supplied to the lock-up release-side oil chamber 27 in the lock 12 and discharged from the lock-up engagement-side oil chamber 28 via the second oil passage system B.

In this state, oil is supplied into the power transmission case 12 through the space between the front cover 12a and the lock-up piston 22, so that the lock-up release-side oil chamber 27 and the lock-up engagement-side oil chamber 28 , The lock-up piston 22 moves to the right in the drawing, and the lock-up piston 22 is separated from the friction material 25. That is, sliding between the friction material 25 and the lock-up piston 22 is not performed, and the lock-up device 14 enters the lock-up off state.

Therefore, the torque generated by the engine is transmitted to the pump impeller 15 via the crankshaft, the drive plate and the power transmission case 12, and the pump impeller 15 rotates. This pump impeller 15
The oil in the power transmission case 12 is circulated from the pump impeller 15 to the pump impeller 15 via the turbine runner 16 and the stator 17 by the rotation of. Since the turbine runner 16 receives a force due to this oil flow, the turbine runner 16 rotates, and the increased torque is transmitted to the turbine runner 16 by the stator 17.

The rotation of the turbine runner 16 is transmitted to an output shaft via a turbine hub 20 and further transmitted to a transmission (not shown). Subsequently, when the rotation speed of the turbine runner 16 exceeds a predetermined speed, the direction of oil flowing out of the turbine runner 16 changes, and the stator 1
7 comes into contact with the back side of the blade beyond the direction of inclination of the blade, so that the stator 17 idles.

During this time, transmission of torque via the lock-up device 14 is not performed. Also, the lock-up device 14
Is set to the lock-up ON state, the oil is supplied to the lock-up engagement side oil chamber 28 in the power transmission case 12 via the second oil passage system B, and the lock-up is performed. It is discharged from the release side oil chamber 27 via the first oil passage system A. As a result, the oil pressure in the lock-up engagement-side oil chamber 28 increases, and the oil pressure in the lock-up release-side oil chamber 27 decreases, and the pressure difference between the lock-up engagement-side oil chamber 28 and the lock-up release-side oil chamber 27 increases. Occurs. Then, due to this pressure difference, the lock-up piston 22 moves to the left in the drawing, and the friction material 25 contacts the front cover 12a. That is, the lock-up device 14
Is a lock-up ON state in which the power transmission case 12 on the driving side and the output shaft on the driven side are directly connected.

When the slip control is performed between the front cover 12a and the lock-up piston 22, the friction material 25 on the front cover 12a is
2 may slide for a long time, causing the temperature of the friction material 25 to rise and burning to occur. Therefore, the friction material 25 can be cooled with a sufficient amount of oil while the lock-up piston 22 is engaged with the front cover 12a and while the lock-up piston 22 is slid. .

FIG. 1 is a sectional view of a principal part of a fluid transmission device according to an embodiment of the present invention, FIG. 2 is an enlarged view of a principal portion of a lock-up piston of the fluid transmission device according to the embodiment of the present invention, and FIG. It is an engagement state figure of the lockup piston in the hydraulic power transmission which shows Example of this. In the drawing, 12a is a front cover, 22 is a lock-up piston, 22b is an outer cylindrical portion of the lock-up piston 22, and 22c is an annular plate of the lock-up piston 22. Reference numeral 25 denotes an annular friction material adhered and fixed to an outer peripheral edge portion of the front cover 12a; 27, a lock-up release side oil chamber; 28, a lock-up engagement side oil chamber; The hole 22c is provided at a position corresponding to the friction material 25.

The hole 35 communicates between the lock-up release side oil chamber 27 and the lock-up engagement side oil chamber 28, while the lock-up piston 22 is engaged with the front cover 12a and slides. During this time, the oil in the lock-up engagement side oil chamber 28 is supplied to the surface of the friction material 25. That is, high-temperature oil staying in the vicinity of the friction material 25 is discharged, and the oil cooled by an oil cooler (not shown) is supplied to the surface of the friction material 25 to cool the entire friction material 25.

When the lock-up piston 22 is slid with respect to the friction material 25 by the slip control, the friction material 25 and the lock-up piston 22 rotate relatively. Therefore, the oil supplied from the hole 35 of the lock-up piston 22 moves on the surface of the friction material 25 with the relative rotation and spreads over the entire friction material 25. Further, as shown in FIG. 2, the hole 35 is formed in a position corresponding to the friction material 25, that is, in a portion F which is in contact with the friction material 25 when the lock-up piston 22 is engaged and slides, in the circumferential direction. It is formed at a plurality of locations, and is distributed at various locations in the radial direction to supply oil to the entire friction material 25.

On the other hand, on the surface of the friction material 25, as shown in FIG. 3, a minute undulation G is formed which does not affect the engagement force between the friction material 25 and the lock-up piston 22. The oil supplied to the surface receives centrifugal force and flows radially outward along the undulation G. Therefore, the oil circulates and the low-temperature oil is constantly supplied to the surface of the friction material 25.

During the slip control, the circulation of oil from the lock-up engagement side oil chamber 28 to the lock-up release side oil chamber 27 between the friction material 25 and the lock-up piston 22 hardly occurs. , Pump impeller 1
The oil whose temperature has risen due to the slip between the turbine runner 5 and the turbine runner 16 stays in the lock-up engagement side oil chamber 28.
The oil passage 21 formed in the turbine hub 20 allows the oil whose temperature has risen to circulate, and the low-temperature oil is always supplied to the lock-up engagement side oil chamber 28.
From 5, low-temperature oil is also supplied to the friction material 25.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a fluid transmission device showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of a lock-up piston of the fluid transmission according to the embodiment of the present invention.

FIG. 3 is an engagement state diagram of a lock-up piston in the fluid transmission according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a fluid transmission according to an embodiment of the present invention.

[Explanation of symbols]

 12a Front cover 15 Pump impeller 16 Turbine runner 22 Lockup piston 25 Friction material 27 Lockup release side oil chamber 28 Lockup engagement side oil chamber

Claims (2)

(57) [Claims] A front cover 1. A torque generated by the engine is transmitted, receiving a pump impeller to rotate the front cover and integrally, the torque from the pump impeller by the flow of oil circulates, said Torr
A turbine runner to transfer the click to the output shaft, attached to the turbine runner, forming the front cover and the lock-up release side oil chamber on the opposite side, and divides the lockup engagement side oil chamber on the opposite side and, and, Yusuke lockup piston selectively disengaged and slide relative to the front cover is made, the friction material and which is fixed to the lock-up piston surface facing the in the front cover
Rutotomoni, wherein a position corresponding to said friction material in the lock-up piston, the lock-up release side oil chamber and holes and a lock-up engagement side oil chamber Ru is communicated is formed a fluid transmission device according to claim Rukoto . 2. The method according to claim 1, wherein the hole is formed on a circumference of a lock-up piston.
Formed at multiple locations in the direction
The fluid transmission device according to claim 1, wherein the fluid transmission device is distributed in various places.
Place.