JP3653295B2 - Cooling structure of wet friction engagement device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a structure for efficiently cooling a wet friction engagement device.
[0002]
[Prior art]
Conventionally, a wet friction engagement device is used as a device that transmits or cuts off a rotational force in, for example, an automatic transmission for an automobile or a transmission for an industrial or construction machine.
As shown in FIG. 4, such a wet friction engagement device has a friction plate, mating plates 12, 13 pressed alternately by hydraulic oil A in a drum 11 in which friction plates, mating plates 12, 13 are alternately arranged. A piston 16 that presses the plates 12 and 13 together and a spring receiver 15 that receives a spring 14 that biases the piston 16 in a direction away from the friction plate and the mating plates 12 and 13 are housed.
[0003]
The wet friction engagement device 10 is in an engaged state when the piston 16 presses the friction plate and the mating plates 12 and 13 to transmit the rotational force, and the piston 16 is separated from the friction plate and the mating plates 12 and 13. When it hits, it will be in the release state and cut off the transmission of rotational force.
When the wet friction engagement device 10 is in the engaged state, the friction plate 12 and the mating plate 13 are pressed against each other while slipping, and thus generate heat and become high temperature. For this reason, the friction plate 12 and the mating plate 13 are cooled by the circulating cooling oil B.
[0004]
[Problems to be solved by the invention]
However, in order to enhance the cooling effect of the friction plate 12 and the mating plate 13, such a wet friction engagement device 10 must supply a large amount of cooling oil B, which is an oil pump (not shown). There is a problem that the driving force must be increased.
[0005]
Further, when the supply amount of the cooling oil B is increased to enhance the cooling effect, the cooling oil B is constantly stirred by the friction plate 12 or the mating plate 13 in the released state of the friction engagement device 10. Therefore, there is also a problem that fuel consumption deteriorates due to so-called “friction loss”.
[0006]
[Means for Solving the Problems]
The present invention includes a piston in which a friction plate and a mating plate are alternately disposed, a piston that is pressed by hydraulic oil to press the friction plate and the mating plate against each other, and the piston as the friction plate and mating. In a wet friction engagement device in which a spring receiver for receiving a spring urging away from a plate is accommodated, the spring receiver and the piston are accommodated by an oil sump cylinder that is accommodated in a side surface of the piston. An oil sump for storing cooling oil formed between the piston and the oil sump, which is closed by the oil sump cylinder that moves integrally with the piston when the piston moves closer to the friction plate and mating plate. The cooling structure is characterized by the fact that an oil discharge passage is formed that goes from the state to the open state. The problem was solved.
[0007]
[Action]
When the hydraulic oil is supplied to the wet friction engagement device, the piston presses the friction plate and the mating plate against the spring to bring the friction engagement device into the engaged state.
When the hydraulic oil is discharged, the piston is pushed back by the spring and separated from the friction plate and mating plate, and the friction engagement device is released.
[0008]
When the friction engagement device is in the released state, the oil sump cylinder is provided in the piston, so that the oil discharge path of the sump is closed by the piston being located away from the friction plate and mating plate.
By closing the oil discharge path, the cooling oil is stored in the oil reservoir, and the cooling oil does not flow into the friction plate and the mating plate.
Therefore, so-called “friction loss” does not occur.
[0009]
When the frictional engagement device is engaged, the oil sump cylinder moves together with the piston and opens the oil discharge passage of the oil sump.
The cooling oil accumulated in the oil sump is discharged when the oil discharge passage is opened, and a larger amount of cooling oil is supplied to the friction plate and mating plate in a shorter time than before, slipping and generating heat. A certain friction plate and mating plate are cooled quickly and reliably.
[0010]
Since the friction plate and mating plate after the friction engagement device is engaged are not slipped and the amount of heat generation is reduced, the cooling oil supplied from the open oil discharge passage is used for cooling. To be cooled.
[0011]
【Example】
Embodiments of the present invention will be described below with reference to FIGS.
As shown in FIG. 1, the wet friction engagement device 20 is pressed by the hydraulic oil A into the drum 21 in which the friction plates 22 and the mating plates 23 are alternately arranged, and the friction plates 22 and the mating plates 23. And a spring receiver 25 that receives a spring 24 that urges the piston 26 in a direction away from the friction plate 22 and the mating plate 23.
[0012]
The friction plate 22 is provided on a spline 31 on the hub 30 provided on the radially inner side of the drum 21 so as to be movable in the directions of arrows C and D via protrusions (not shown).
The mating plate 23 is provided on a spline 32 provided on the inner periphery of the drum 21 so as to be movable in the directions of arrows C and D via protrusions (not shown).
[0013]
The piston 26 is provided in the drum 21 so as to be movable in the directions of arrows C and D by oil seals 36 and 37.
An oil sump cylinder 40 that houses the spring 24 and the spring receiver 25 is provided on the side surface of the piston 26.
[0014]
A donut-shaped space surrounded by the piston 26, the oil sump cylinder 40, the spring receiver 25, and the cylindrical sleeve 34 is an oil sump 50, and the cooling oil B is oil holes of the cylindrical sleeve 34 by an oil pump (not shown). 51 is supplied.
The inner diameter of the oil sump cylinder 40 is set larger than the outer diameter of the spring receiver 25, and a gap as an oil discharge path 60 is generated between the inner diameter of the oil sump cylinder 40 and the outer diameter of the spring receiver 25. .
[0015]
At the base end (the left end in FIG. 1) of the oil sump cylinder 40, an outward flange 41 extending outward from the oil sump cylinder 40 is formed. The oil sump cylinder 40 is attached to the piston 26 by a snap ring 42 that engages the outward flange 41. An oil seal 43 is sandwiched between the outward flange 41 and the piston 26.
An inward flange 44 extending inward of the oil sump cylinder 40 is formed at the tip of the oil sump cylinder 40. An oil seal 45 that contacts the spring receiver 25 is attached to the inward flange 44.
The oil seals 43 and 45 serve to seal the oil sump 50.
[0016]
The spring receiver 25 is prevented from coming off by a snap spring 52 provided on the cylindrical sleeve 34, and a drain hole 53 for discharging the excess cooling oil B in the oil sump 50 is formed on the side surface.
[0017]
Next, the operation will be described.
When the hydraulic oil A is supplied to the wet friction engagement device 20, the piston 26 moves in the direction of the arrow C against the spring 24, and presses the friction plate 22 and the mating plate 23. 20 is engaged.
When the hydraulic oil A is discharged, the piston 26 is pushed back by the spring 24 to leave the friction plate 22 and the mating plate 23, and the friction engagement device 20 is released.
[0018]
When the friction engagement device 20 is in the released state, the piston 26 is located away from the friction plate 22 and the mating plate 23, and the oil sump cylinder 40 is provided on the piston 26. The oil seal 45 is pressed against the spring receiver 25 with the inward flange 44, and the oil discharge path 60 is closed.
[0019]
The oil reservoir 50 is supplied with the cooling oil B through an oil hole 51 by an oil pump and is stored. For this reason, the cooling oil B is hardly supplied to the friction plate 22 and the mating plate 23, so that “friction loss” does not occur.
The cooling oil B stored in the oil sump 50 is separated from the cylindrical sleeve 34 by the centrifugal force generated by the rotation of the drum 21 and is accumulated on the inner wall of the oil sump cylinder 40 as shown in FIG.
[0020]
When the friction engagement device 20 is engaged, the piston 26 moves rightward in FIG. 1 and approaches the friction plate 22 and the mating plate 23. At the same time, the oil sump cylinder 40 also moves to the right in FIG. 1, and the oil seal 45 is separated from the spring receiver 25 by the inward flange 44, and the oil discharge passage 60 is opened (see FIG. 2).
The cooling oil B accumulated in the oil sump 50 flows out at the same time as the oil discharge passage 60 is opened. As shown by the solid line in FIG. 3, the flow rate immediately after opening the oil discharge passage 60 is higher than that in the prior art, and the friction plate 22 and mating plate 23 that are in a heated state due to slipping are cooled quickly and reliably. Is done.
[0021]
The flow rate of the cooling oil B flowing out from the oil discharge passage 60 after the friction engagement device 20 is in the engaged state is substantially the same as the flow rate of the cooling oil B supplied from the oil hole 51. Less than the flow rate. The friction plate 22 and the mating plate 23 in the engaged state are sufficiently slipped even if the flow rate of the cooling oil B is smaller than the conventional one because the slip and the heat generation amount are small.
[0022]
Note that when the amount of the cooling oil B stored in the oil sump 50 increases in the released state of the friction engagement device 20 (overflow state), the cooling oil B flows out from the drain hole 53 accordingly. The flow rate of the cooling oil B flowing out from the drain hole 53 is substantially the same as the flow rate of the cooling oil B supplied from the oil hole 51.
For this reason, the oil pump is not overloaded.
[0023]
【The invention's effect】
According to the cooling structure of the present invention, in the released state of the wet friction engagement device, the cooling oil is stored in the oil sump, and almost no cooling oil is supplied to the friction plate and mating plate, thereby reducing the friction loss. be able to.
Further, according to the cooling structure of the present invention, when the wet friction engagement device is engaged, a large amount of the cooling oil accumulated during the release state of the friction engagement device can be allowed to flow out from the oil reservoir in a short time. Therefore, the friction plate and mating plate that are in a heat generation state due to slipping can be quickly and reliably cooled.
Furthermore, a large amount of the cooling oil stored in the oil sump during the release state of the friction engagement device can flow out in a short time, so that the friction plate and mating plate are not increased without increasing the driving force of the oil pump. The cooling effect can be enhanced.
[Brief description of the drawings]
FIG. 1 is a front view in a released state of a wet friction engagement device incorporating a cooling structure according to an embodiment of the present invention, and is a cross-sectional view along an axial direction.
FIG. 2 is a front view of an engagement state of the friction engagement device in FIG. 1, and is a cross-sectional view along the axial direction.
FIG. 3 shows the friction plate of the wet friction engagement device incorporating the cooling structure of the embodiment of the present invention, the flow rate of the cooling oil flowing through the mating plate in solid lines, the friction plate of the conventional friction engagement device, It is the graph which showed the flow volume of the cooling oil which flows into a mating plate with the broken line, the flow volume per unit time is shown on a vertical axis | shaft, and the time and the operation state of a friction engagement apparatus are shown on the horizontal axis.
FIG. 4 is a front view of the wet friction engagement device in a released state, and is a cross-sectional view along the axial direction.
[Explanation of symbols]
A Hydraulic oil B Cooling oil 20 Wet friction engagement device 21 Drum 22 Friction plate 23 Mating plate 24 Spring 25 Spring receiver 26 Piston 40 Oil reservoir cylinder 50 Oil reservoir 60 Oil discharge passage

Claims (1)

In a drum in which friction plates and mating plates are alternately disposed, a piston that presses the friction plates and the mating plate against each other by being pressed by hydraulic oil, and a direction in which the piston moves away from the friction plates and the mating plate In the wet friction engagement device in which the spring receiver that receives the spring that is biased to is housed,
An oil sump for storing cooling oil formed between the spring receiver and the piston is provided by an oil sump cylinder provided in a side surface of the piston and accommodating the spring receiver, and the piston is disposed in the oil sump. The wet friction engagement device is characterized in that an oil discharge passage is formed from the closed state to the open state by the oil sump cylinder that moves integrally with the piston when moving closer to the friction plate and mating plate. Cooling structure.

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