JP6997693B2 - Wet multi-plate clutch with friction plate and friction plate - Google Patents

Description

The present invention relates to a wet multi-plate clutch provided with a friction plate and a friction plate used in a sealed oil reservoir environment such as in a torque converter for an automatic transmission. More specifically, the present invention relates to a friction plate having excellent heat resistance and durability during slip control in a sealed oil reservoir environment, and a wet multi-plate clutch provided with the friction plate.

Generally, in a wet multi-plate clutch, friction plates (friction plates) and separator plates are alternately arranged between the clutch or brake drum and the hub, and the clutch can be engaged and disengaged by pressing and disengaging the clutch piston. Will be done.

In such a wet multi-plate clutch, when it is used in a sealed oil reservoir environment, it may be used in a constant slip state until the wet multi-plate clutch is engaged.

In particular, for lockup clutches for torque converters for automatic transmissions, slip control is indispensable for the demand for low fuel consumption, and the demand for friction plates that enable this is becoming a trend in recent years.

The prior art document information related to the invention of this application includes the following.

Japanese Unexamined Patent Publication No. 2007-51759

Under the conditions of use in a sealed oil reservoir environment, the friction plate of the wet multi-plate clutch is significantly damaged to the friction material, and it is a problem to cool the friction plate to reduce the heat storage damage.

Generally, in order to suppress the influence of heat storage and improve the cooling property, there is a method of providing a groove in the friction material of the clutch to improve the oil discharge property and the cooling property. However, these have a problem that the drag torque increases because the contact (internal pressure) with the mating surface becomes strong. Further, if a groove opened in the inner diameter is used as described in Patent Document 1 in order to reduce the drag torque, the area of the friction material is reduced, and there is a problem that the heat resistance tolerance is lowered.

Further, in recent years, the demand for low fuel consumption of automobiles has been increasing more and more, and in order to reduce the power loss when the clutch is not engaged, it is further required to reduce the drag torque between the friction plate and the separator plate. Therefore, there has been a demand for a wet multi-plate clutch using a friction plate and a friction plate that can cool the friction material while reducing the drag torque.

Therefore, an object of the present invention is to provide a friction plate of a wet multi-plate clutch used in a sealed oil reservoir environment, in which the cooling property of the friction material is improved by improving the oil discharge property. That is.

In order to achieve the above object, the friction plate of the present invention is used.
A friction plate having a friction surface formed by fixing a plurality of friction material segments in an annular shape to a substantially annular core plate.
A through groove is formed between the friction material segments so as to penetrate from the inner diameter side to the outer diameter side of the core plate.
In the friction material segment, a peripheral groove that opens in the through groove and extends in the circumferential direction that terminates in the friction material segment is formed.
The peripheral groove is characterized in that one is formed near the outer diameter of one end of the friction material segment in the circumferential direction and one is formed near the inner diameter of the other end.

According to the present invention, the following effects can be obtained.

The peripheral groove extending in the circumferential direction accelerates the oil discharge property, and the cooling property is improved by improving the discharge property, so that the heat storage damage to the friction material can be reduced.

By generating pressure on the friction surface by the oil overflowing from the peripheral groove flowing in the axial direction, a pulling effect is produced and the drag torque can be reduced.

Further, since the peripheral groove may be formed in a small area, a large friction material area can be obtained, heat resistance can be improved, and a pulling effect can also be obtained.

It is an axial partial sectional view of the wet multi-plate clutch provided with the friction plate of this invention. It is a partial front view of the friction plate which shows 1st Embodiment of this invention. It is a front view which shows the friction material segment of 1st Embodiment of this invention. It is a front view of the friction material segment which shows the 2nd Embodiment of this invention. It is a front view of the friction material segment which shows 3rd Embodiment of this invention. It is a front view of the friction material segment which shows 4th Embodiment of this invention. It is a front view of the friction material segment which shows 5th Embodiment of this invention. It is a front view of the friction material segment which shows 6th Embodiment of this invention. FIG. 3 is an axial partial cross-sectional view of a wet multi-plate clutch provided with another friction plate of the present invention. It is a graph which shows the relationship between the sliding time (sec) and the friction surface temperature (° C.) in the friction plate of 1st Example and the comparative example of this invention. It is a graph which shows the relationship between the relative rotation speed (rpm) and the drag torque (Nm) in the friction plate of the 1st Example and the comparative example of this invention.

As used herein, the term "peripheral groove" refers to a groove extending in the circumferential direction, but also includes a groove extending in a direction slightly angled in the circumferential direction. Further, the "sealed oil reservoir environment" refers to an environment in which a large amount of oil circulates in an oil-tight structure without supplying oil from the outside such as a torque converter. If it is oil-tight, it is suitable for applications other than torque converters.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same parts are indicated by the same reference numerals.

FIG. 1 is an axial partial cross-sectional view of a wet multi-plate clutch 10 provided with the friction plate of the present invention.

The wet multi-plate clutch 10 has a substantially cylindrical clutch drum 1 opened at one end in the axial direction, a hub 4 arranged on the inner circumference of the clutch drum 1 and rotating relative to each other on the same axis, and the inner circumference of the clutch drum 1. An annular separator plate 2 is arranged so as to be movable in the axial direction on the spline 8 provided on the hub 4, and the separator plate 2 and the friction material segment are alternately arranged on the spline 5 provided on the outer periphery of the hub 4 in the axial direction. It is composed of an annular friction plate 3 having friction surfaces fixed with an adhesive or the like on both sides in the axial direction. The separator plate 2 has a spline portion 2a that engages with the spline 8, and the friction plate 3 has a spline portion 3a that engages with the spline 5. A plurality of friction plates 3 and a plurality of separator plates 2 are provided.

The wet multi-plate clutch 10 holds the piston 6 that presses and fastens the separator plate 2 and the friction plate 3 and the separator plate 2 and the friction plate 3 in a fixed state at one end in the axial direction, so that the inner circumference of the clutch drum 1 is fixed. It is provided with a backing plate 7 provided in the vehicle and a retaining ring 17 for holding the backing plate 7.

As shown in FIG. 1, the piston 6 is arranged so as to be slidable in the axial direction within the closed end of the clutch drum 1. An O-ring 9 is interposed between the outer peripheral surface of the piston 6 and the inner surface of the clutch drum 1. Further, a seal member (not shown) is interposed between the inner peripheral surface of the piston 6 and the outer peripheral surface of the inner peripheral cylindrical portion (not shown) of the clutch drum 1. Therefore, an oil-tight hydraulic chamber 11 is defined between the inner surface of the closed end of the clutch drum 1 and the piston 6.

The friction plate 3 is held on the hub 4 so as to be slidable in the axial direction, and friction material segments 12 and 13 having a predetermined friction coefficient are fixed on both sides thereof. However, the friction material segments 12 and 13 can also be provided on only one side of the friction plate 3. Further, the hub 4 is provided with a lubricating oil supply port 15 penetrating in the radial direction, and lubricating oil is supplied from the inner diameter side to the outer diameter side of the wet multi-plate clutch 10 through the lubricating oil supply port 15. ..

The wet multi-plate clutch 10 configured as described above engages (engages) and disengages the clutch as follows. The state of FIG. 1 shows the clutch disengaged state, and the separator plate 2 and the friction plate 3 are separated from each other. In the released state, the piston 6 is in contact with the closed end side of the clutch drum 1 due to the urging force of the return spring (not shown).

In order to engage the wet multi-plate clutch 10 in this state, hydraulic pressure is supplied to the hydraulic chamber 11 defined between the piston 6 and the clutch drum 1. As the hydraulic pressure rises, the piston 6 moves to the right in the axial direction in FIG. 1 against the urging force of the return spring (not shown), and the separator plate 2 and the friction plate 3 are brought into close contact with each other. As a result, the wet multi-plate clutch 10 is engaged.

After the wet multi-plate clutch 10 is engaged, in order to release the wet multi-plate clutch 10 again, the hydraulic pressure in the hydraulic chamber 11 is released. When the hydraulic pressure is released, the piston 6 moves to a position where it comes into contact with the closed end of the clutch case 1 by the urging force of the return spring (not shown). That is, the wet multi-plate clutch 10 is released.

(First Example)
FIG. 2 is a partial front view of the friction plate 3 showing the first embodiment of the present invention. The friction plate 3 has a friction surface 25 formed by fixing friction material segments 12 and 13 to a substantially annular core plate 20 in an annular shape with an adhesive or the like. The core plate 20 is provided with a spline 20a on the inner circumference that engages with the spline 5 of the hub 4.

As shown in FIG. 2, a pair of friction material segments 12 and 13 are arranged in an annular shape on the friction plate 3. Between the friction material segments 12 and 13, through grooves 21 and 22 penetrating from the inner diameter to the outer diameter of the core plate 20 and extending radially are formed.

Peripheral grooves 12a and 13a that open in the through groove 21 and extend in the circumferential direction are formed in the friction material segments 12 and 13, respectively. The peripheral grooves 12a and 13a are provided symmetrically in the radial direction of the friction material segment. The peripheral grooves 12a and 13a are provided symmetrically with respect to the through groove 21 and face each other with the through groove 21 interposed therebetween. Moreover, they are arranged at the same position in the radial direction.

The peripheral groove 12a of the friction material segment 12 opens in the through groove 21 and terminates and closes inside the friction material segment 12 in the circumferential direction. Similarly, the peripheral groove 13a of the friction material segment 13 opens in the through groove 21 and terminates and closes inside the friction material segment 13 in the circumferential direction.

The peripheral groove 12a of the friction material segment 12 is provided at one end of the friction material segment 12 in the circumferential direction, and is not provided at the other end. Similarly, the peripheral groove 13a of the friction material segment 13 is provided at one end of the friction material segment 13 in the circumferential direction, and is not provided at the other end.
Another through groove 22 is formed between the friction material segment 12 and the friction material segment 13 in which the peripheral groove is not provided.

As described above, in the first embodiment, the pair of friction material segments 12 and 13 are arranged in an annular shape, and the through grooves 21 communicating with the peripheral grooves 12a and 13a and the through grooves 22 not communicating with each other are alternately arranged. .. The peripheral groove 12a and the peripheral groove 13a are formed in the middle of the friction material segments 12 and 13 in the radial direction, respectively, but they can be formed in other positions as long as they are at the same radial position.

FIG. 3 is a front view showing the friction material segment of the first embodiment of the present invention, and is a diagram for explaining the function of the peripheral groove provided in the friction material segment. As described above, the pair of adjacent friction material segments 12 and 13 are provided with peripheral grooves 12a and 13a facing each other with the through groove 21 interposed therebetween.

The pair of friction material segments 12 and 13 are fixed to the core plate 20 in an annular shape in the circumferential direction in the combination shown in the figure. This also applies to the second to sixth embodiments described below.

The peripheral groove 12a includes an opening 12c that opens in the through groove 21 and a terminal portion 12b that terminates in the friction material segment 12. Similarly, the peripheral groove 13a includes an opening 13c that opens in the through groove 21 and a terminal portion 13b that terminates in the friction material segment 13. As shown in FIG. 3, the opening 12c of the peripheral groove 12a and the opening 13c of the peripheral groove 13a face each other in the circumferential direction with the through groove 21 interposed therebetween.

Next, the function of the peripheral groove will be described. As shown in FIG. 3, a part of the lubricating oil supplied from the lubricating oil supply port 15 of the hub 4 holding the friction plate 3 to the friction plate 3 from the inner diameter direction is a through groove 21 passing through the clutch portion. It passes through and 22 and flows to the outer diameter side. This flow is indicated by an arrow R. The oil passing through the through grooves 21 and 22 serves not only as a lubricating function but also as a cooling material for lowering the heat accumulated on the frictional engagement surface between the friction plate 3 and the separator plate 4.

The oil in the through groove 21 flows from the inner diameter side to the outer diameter side as shown by the arrow R. At this time, the oil that has entered the peripheral grooves 12a and 13a from the through groove 21 rotates in the peripheral grooves as shown by arrows A and B, respectively. The rotational energy of this rotating oil is transmitted to the oil passing through the through groove 21, and serves to accelerate the flow velocity of the oil passing through the through groove 21. As a result, the dischargeability of discharging the oil in the through groove 21 in the outer diameter direction is improved. Therefore, the cooling performance of the clutch portion including the friction plate 3 and the separator plate 4 is improved.

Since the cooling property is improved as described above, the heat storage damage to the friction material segments 12 and 13 can be reduced. Further, the drag torque can be reduced by the pulling effect generated by the oil entering the peripheral grooves 12a and 13a flowing in the axial direction and riding on the friction surface 25 as shown by the plurality of arrows C shown in FIG. Further, since the peripheral groove may be formed in a small area, the area of the friction surface 25 can be made large, the heat resistance of the friction material can be improved, and the pulling effect can also be obtained.

Needless to say, the peripheral grooves of the second to sixth embodiments described below also have the function of accelerating the flow velocity of the oil in the through groove.

(Second Example)
FIG. 4 is a front view of a friction material segment showing a second embodiment of the present invention. The pair of friction material segments 32 and 33 have the same shape. The friction material segment 32 is provided with peripheral grooves 32a at both ends in the circumferential direction. Similarly, the friction material segment 33 is also provided with peripheral grooves 33a at both ends in the circumferential direction. In this embodiment, two peripheral grooves are formed at the same radial position in one friction material segment. The peripheral grooves 32a and 33a are provided substantially in the middle of the friction material segment in the radial direction. The peripheral grooves 32a and 33a are provided symmetrically with respect to the through groove 21.

In the second embodiment, the oil flowing through all the through grooves 21 and the through grooves 22 between the friction material segment 32 and the friction material segment 33 can be accelerated. Therefore, the cooling efficiency is higher than in the case of the first embodiment, and the heat storage damage of the friction material segment can be more effectively eliminated.

(Third Example)
FIG. 5 is a front view of a friction material segment showing a third embodiment of the present invention. The pair of friction material segments 42 and 43 have the same shape. The friction material segment 42 is provided with a peripheral groove 42a at one end in the circumferential direction. Similarly, the friction material segment 43 is also provided with a peripheral groove 43a at one end in the circumferential direction. As shown in FIG. 5, the peripheral groove 42a and the peripheral groove 43a are open in the same direction. The peripheral grooves 42a and 43a are provided substantially in the middle of the friction material segment in the radial direction. However, the peripheral grooves 42a and 43a are provided asymmetrically with respect to the through groove 21.

In the third embodiment, as in the second embodiment, the oil flowing through all the through grooves 21 and the through grooves 22 between the friction material segment 42 and the friction material segment 43 can be accelerated. One peripheral groove is provided for one through groove, and an effect close to that of the first embodiment can be obtained.

(Fourth Example)
FIG. 6 is a front view of a friction material segment showing a fourth embodiment of the present invention. The pair of friction material segments 52 and 53 have the same shape. The friction material segment 52 is provided with a peripheral groove 52a at one end in the circumferential direction. Similarly, the friction material segment 53 is also provided with a peripheral groove 53a at one end in the circumferential direction. As shown in FIG. 6, the peripheral groove 52a and the peripheral groove 53a are open in the same direction. It opens in the direction opposite to the peripheral groove of the third embodiment in the circumferential direction. The peripheral grooves 52a and 53a are provided substantially in the middle of the friction material segment in the radial direction. However, the peripheral grooves 52a and 53a are provided asymmetrically with respect to the through groove 21.

In the fourth embodiment, as in the second embodiment, the oil flowing through all the through grooves 21 between the friction material segment 52 and the friction material segment 53 and the through grooves 22 can be accelerated. One peripheral groove is provided for one through groove, and an effect close to that of the first embodiment can be obtained.

(Fifth Example)
FIG. 7 is a front view of the friction material segment showing the fifth embodiment of the present invention. Similar to the second embodiment, the pair of friction material segments 62 and 63 each have two peripheral grooves formed at both ends in the circumferential direction. However, the radial positions of the two peripheral grooves are different.

In the friction material segment 62, a peripheral groove 62a is formed near the outer diameter of one end in the circumferential direction, and a peripheral groove 62b is formed near the inner diameter of the other end. On the other hand, in the friction material segment 63, a peripheral groove 63a is formed near the outer diameter of one end in the circumferential direction, and a peripheral groove 63b is formed near the inner diameter of the other end. The peripheral grooves 62a and 63a are provided asymmetrically with respect to the through groove 21.

The peripheral groove 62a and the peripheral groove 63a are close to the outer diameter and face each other at the same position in the radial direction with the through groove 21 interposed therebetween. Further, the peripheral groove 62b and the peripheral groove 63b are close to the inner diameter and face each other at the same position in the radial direction with the through groove 22 (not shown in FIG. 7) interposed therebetween.

In the fifth embodiment, as in the second embodiment, the oil flowing through all the through grooves 21 between the friction material segment 62 and the friction material segment 63 and the through grooves 22 can be accelerated. Therefore, the cooling efficiency is higher than that of the first embodiment, and the heat storage damage of the friction material segment can be more effectively eliminated.

(6th Example)
FIG. 8 is a front view of the friction material segment showing the sixth embodiment of the present invention. Similar to the second embodiment, the pair of friction material segments 72 and 73 have two peripheral grooves formed at both ends in the circumferential direction, respectively. However, the radial positions of the two peripheral grooves are different. The peripheral grooves 72a and 73a are provided asymmetrically with respect to the through groove 21.

In the friction material segment 72, a peripheral groove 72a is formed near the outer diameter of one end in the circumferential direction, and a peripheral groove 72b is formed near the inner diameter of the other end. On the other hand, in the friction material segment 73, a peripheral groove 73a is formed near the outer diameter of one end in the circumferential direction, and a peripheral groove 73b is formed near the inner diameter of the other end.

The peripheral groove 72b and the peripheral groove 73b are close to the inner diameter and face each other at the same position in the radial direction with the through groove 21 interposed therebetween. Further, the peripheral groove 72b and the peripheral groove 73b are close to the outer diameter and face each other at the same position in the radial direction with the through groove 22 (not shown in FIG. 8) interposed therebetween.

In the sixth embodiment, similarly to the second embodiment, the oil flowing through all the through grooves 21 between the friction material segment 72 and the friction material segment 73 and the through groove 22 can be accelerated. Therefore, the cooling efficiency is higher than that of the first embodiment, and the heat storage damage of the friction material segment can be more effectively eliminated.

When the through groove 21 and the through groove 22 are configured to have exactly the same shape, the fifth embodiment and the sixth embodiment have substantially the same configuration.

In each of the above-described embodiments, the peripheral grooves of the first to fourth embodiments are provided substantially in the middle in the radial direction of the friction material segment, but can be provided at other positions. It is also possible to provide a plurality of circumferential grooves at one end of the friction material segment, but it is preferable to provide as few as possible because the area of the friction material segment, that is, the area of the friction surface is reduced. ..

Each friction material segment is attached by applying an adhesive to the core plate 20, and a seal-shaped friction material segment having an adhesive applied to the back surface is placed on the core plate 20 and attached by pressing and heating. You can also wear it.

FIG. 9 is an axial partial cross-sectional view of a wet multi-plate clutch provided with another friction plate of the present invention. Unlike the friction plate 3 shown in FIG. 1, the friction plate 3 shown in FIG. 9 has a friction material segment 12 fixed to only one surface in the axial direction. On the other hand, the friction material segment 12 is fixed to the axial surface of the separator plate 2 facing the surface of the friction plate 3 to which the friction material segment 12 is not fixed. In the above description, the friction material segment 12 represents the friction material segment, but other friction material segments 13, 32, 33, 42, 43, 52, 53, 62, 63, 72, 73 may be used in the same manner. can.

FIG. 10 is a graph showing the relationship between the sliding time (sec) and the friction surface temperature (° C.) in the friction plates of the first embodiment and the comparative example (conventional example) of the present invention. It can be seen that in the friction plate of each embodiment of the present invention in which the peripheral groove is formed, the friction surface temperature remains lower than in the comparative example in which the peripheral groove is not formed.

FIG. 11 is a graph showing the relationship between the relative rotation speed (rpm) and the drag torque (Nm) in the friction plates of the first embodiment and the comparative example (conventional example) of the present invention. It can be seen that in the friction plate of each embodiment of the present invention in which the peripheral groove is formed, the drag torque remains lower than in the comparative example in which the peripheral groove is not formed. In particular, in the rotation range where the relative rotation speed is larger than 1000 rpm, it is considerably lower than the conventional one.

In the graphs shown in FIGS. 10 and 11, the “example” corresponds to the friction plate according to the first embodiment of the present invention shown in FIG. 2, and the “comparative example” refers to the friction material segment of FIG. It corresponds to the friction plate when no groove is provided.

As described above, the present invention suitable for use in a sealed oil reservoir environment can be used in a lockup clutch in a torque converter, a vehicle equipped with an automatic transmission, or the like.

1 Clutch drum 2 Separator plate 3 Friction plate 4 Hub 5 Spline 6 Piston 8 Spline 10 Wet multi-plate clutch 20 Core plate 21 Through groove 22 Through groove 25 Friction surface 12, 13, 32, 33, 42, 43 Friction material segment 52, 53, 62, 63, 72, 73 Friction segment 12a, 13a, 32a, 33a, 42a, 43a Circumferential groove 53a, 53a, 62a, 63a, 72a, 73a Circumferential groove

Claims (13)

A friction plate having a friction surface formed by fixing a plurality of friction material segments in an annular shape to a substantially annular core plate.
A through groove is formed between the friction material segments so as to penetrate from the inner diameter side to the outer diameter side of the core plate.
The friction material segment is formed with a peripheral groove that opens in the through groove and extends in the circumferential direction of the core plate that terminates in the friction material segment.
The oil passes through the through groove, and the oil flowing into the peripheral groove rotates in the peripheral groove to accelerate the oil passing through the through groove, and the rotated oil rides on the friction surface.
In the through groove, the first through groove having a constant width in the circumferential direction and the second through groove wider than the width of the first through groove are alternately arranged in the circumferential direction. A friction plate characterized by being formed. The friction plate according to claim 1, wherein the friction material segment is long in the radial direction, and the length in the radial direction is longer than the length in the circumferential direction. The friction plate according to claim 1 or 2, wherein the peripheral groove communicates with the first through groove and does not communicate with the second through groove. The friction plate according to claim 1 or 2, wherein the peripheral grooves are formed at both ends of the friction material segment in the circumferential direction. The friction plate according to any one of claims 1 to 4, wherein the peripheral grooves of the adjacent friction material segments face each other with the first through groove interposed therebetween. The friction plate according to claim 5, wherein the facing peripheral grooves are arranged at the same position in the radial direction. The friction plate according to any one of claims 1 to 6, wherein the peripheral grooves are arranged at different positions in the radial direction. The friction plate according to any one of claims 1 to 4, wherein the peripheral groove of the adjacent friction material segment is provided asymmetrically with respect to the through groove. The circumferential length of the peripheral groove is longer than the radial width of the peripheral groove, and the radial width of the peripheral groove is the peripheral of the peripheral groove from the open end to the closed end of the peripheral groove. The friction plate according to any one of claims 1 to 8, wherein the friction plates are substantially the same along the length in the direction. The friction plate according to any one of claims 1 to 9, wherein the friction plate is used in a sealed oil reservoir environment. A wet multi-plate clutch comprising the friction plate according to any one of claims 1 to 10 and the friction plates and separator plates alternately arranged in the axial direction. The wet multi-plate clutch according to claim 11, wherein the friction plate has the friction material segment fixed to one surface in the axial direction. The wet multi-plate clutch according to claim 11, wherein the friction plate has the friction material segments fixed on both sides in the axial direction.

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