CN113153942A

CN113153942A - Wet friction coupling device

Info

Publication number: CN113153942A
Application number: CN202110060608.3A
Authority: CN
Inventors: 松尾道宪
Original assignee: JATCO Ltd
Current assignee: JATCO Ltd
Priority date: 2020-01-22
Filing date: 2021-01-18
Publication date: 2021-07-23
Also published as: JP2021116827A

Abstract

The invention provides a wet friction coupling device for suppressing vibration. The forward clutch (2) has a drive plate (21) and a driven plate (22) (second friction member), and has a groove (223) formed on the surfaces (22a, 22b) of a base (220) of the driven plate (22) that faces the drive plate (21).

Description

Wet friction coupling device

Technical Field

The present invention relates to a wet friction coupling device.

Background

A wet friction coupling device of an automatic transmission provided in a vehicle has a drive plate and a driven plate arranged alternately in a rotation axis direction. The drive plate is fitted to the outer periphery of the inner-diameter-side rotating body of the rotating shaft, and the driven plate is fitted to the inner periphery of the outer-diameter-side rotating body.

The wet friction coupling device includes a hydraulically operated piston that presses a drive plate and a driven plate in a rotation axis direction to couple the drive plate and the driven plate to each other in a relatively non-rotatable manner, thereby transmitting a rotational force between an inner diameter side rotating body and an outer diameter side rotating body.

A friction lining material is attached to the opposite surface of the drive plate to the driven plate. The friction lining material is pressed by a piston and brought into contact with an opposing surface of a driven plate to generate a frictional force, whereby the driving plate and the driven plate are coupled (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent publication No. 2017-96366

Disclosure of Invention

Technical problem to be solved by the invention

When the coupling and release of the drive plate and the driven plate are switched, the drive plate and the driven plate temporarily become a sliding state and generate heat. Therefore, although oil having a friction adjusting function and a cooling function is supplied between the drive plate and the driven plate, it is necessary to improve the cooling performance of the oil.

Technical solution for solving technical problem

The wet-type friction coupling device of the present invention is,

comprising: a first friction member and a second friction member,

the friction member has a groove formed on a surface of a base portion of the second friction member facing the first friction member.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the groove portion provided in the second friction member facing the first friction member improves the cooling performance of the oil supplied between the first friction member and the second friction member.

Drawings

Fig. 1 is a diagram illustrating the structure of the forward/reverse switching mechanism.

Fig. 2 is an exploded perspective view of the forward clutch.

Fig. 3 is a view of the drive plate of the forward clutch as viewed from the direction of the rotation axis.

Fig. 4(a) is a view of a driven plate of the forward clutch viewed from the direction of the rotation axis, fig. 4(b) is an example of an enlarged view of a groove portion, and fig. 4(c) is another example of an enlarged view of a groove portion.

Fig. 5 is an enlarged view of the area a of fig. 1.

FIG. 6 is a view showing details of the groove portion.

Fig. 7 is a graph showing the μ V characteristic of the driven plate.

Fig. 8 is a diagram illustrating a structure of a groove portion according to a first modification.

Fig. 9 is a diagram illustrating a structure of a groove portion according to a second modification.

Fig. 10 is a diagram illustrating the structure of the torque converter.

Detailed Description

The wet friction coupling device according to the embodiment of the present invention will be described below with reference to the drawings. In the embodiment, an example of a forward clutch included in a forward/reverse switching mechanism of a vehicle will be described as an example of a wet friction engagement device.

Fig. 1 is a diagram showing the structure of the forward/reverse switching mechanism.

Fig. 2 is an exploded perspective view of the forward clutch.

As shown in fig. 1, the forward/reverse switching mechanism 5 includes: the forward clutch 2 directly connecting the sun gear 41 and the carrier 44 of the planetary gear set 4 and the reverse brake 3 fixing the clutch drum 25. The forward/reverse switching mechanism 5 outputs the rotational driving force input from an engine, not shown, as it is when the forward clutch 2 is engaged, and outputs the rotational driving force by reversing the rotational driving force when the reverse brake 3 is engaged.

The forward clutch 2 and the reverse brake 3 are located inside the transmission case 10 between the front cover portion 11 of the transmission case 10 and the planetary gear set 4.

The reverse brake 3 is located on the outer diameter side of the forward clutch 2, and includes: an annular driven plate 32 spline-fitted to the inner periphery of the transmission case 10, an annular drive plate 31 spline-fitted to the outer periphery of the clutch drum 25, and a piston 33 that strokes in the axial direction of the rotation axis X (hereinafter, the rotation axis X direction) by hydraulic pressure.

The clutch drum 25 has a cylindrical peripheral wall portion 251 and a bottom portion 250 extending from one end of the peripheral wall portion 251 toward the inner diameter side, and the clutch drum 25 is formed in a bottomed cylindrical shape in cross section.

As shown in fig. 2, when viewed from the direction of the rotation axis X, the spline ridge portions 251a and the spline valley portions 251b of the peripheral wall portion 251 on the outer diameter side are alternately connected in the circumferential direction around the rotation axis X, and splines are formed on the inner periphery and the outer periphery of the peripheral wall portion 251 in the direction of the rotation axis X.

As shown in fig. 1, a plurality of drive plates 31 are provided on the outer periphery of the peripheral wall portion 251 in a spline-fitted manner, and each of the drive plates 31 is provided so as to be movable in the direction of the rotation axis X in a state where relative rotation with the peripheral wall portion 251 in the circumferential direction around the rotation axis X is restricted.

The driven plate 32 located radially outward of the peripheral wall portion 251 is also provided movably in the direction of the rotation axis X in a state where relative rotation with the transmission case 10 in the circumferential direction around the rotation axis X is restricted.

The driven plate 32 and the drive plate 31 of the backing brake 3 are alternately arranged in the direction of the rotation axis X, and the drive plate 31 is arranged so that the outer diameter side of the drive plate 31 overlaps the inner diameter side of the driven plate 32 as viewed in the direction of the rotation axis X.

The portion where the drive plate 31 and the driven plate 32 overlap each other is pressed in the direction of the rotation axis X by a piston 33 provided on the opposite side of the front cover portion 11.

The piston 33 is displaced toward the front cover 11 by supplying hydraulic pressure to an oil chamber, not shown, and presses the drive plate 31 and the driven plate 32.

In the reverse brake 3, relative rotation between the drive plate 31 and the driven plate 32 is restricted by the coupling state between the drive plate 31 and the driven plate 32 due to the pressing of the piston 33.

Therefore, when the drive plate 31 and the driven plate 32 are in a relatively non-rotatably coupled state, the driven plate 32 is spline-fitted to the inner periphery of the transmission case 10, and therefore, the clutch drum 25 spline-fitted to the drive plate 31 can prevent rotation about the rotation axis X.

The forward clutch 2 located on the inner diameter side of the reverse brake 3 includes: the clutch hub 24 includes a driven plate 22 spline-fitted to the inner periphery of the peripheral wall 251 of the clutch drum 25, a drive plate 21 spline-fitted to the outer periphery of the cylindrical peripheral wall 241 of the clutch hub 24, and a piston 23 stroked in the direction of the rotation axis X by hydraulic pressure.

As shown in fig. 1, the clutch hub 24 has a cylindrical peripheral wall portion 241 and a bottom portion 240 extending from one end of the peripheral wall portion 241 toward the inner diameter side, and the clutch hub 24 is formed in a bottomed cylindrical shape in cross section.

In the transmission case 10, the clutch hub 24 and the clutch drum 25 are assembled from the rotation axis X direction in a direction in which the openings thereof face each other, and in this state, the clutch hub 24 is housed inside the peripheral wall portion 251 of the clutch drum 25 (see fig. 1 and 2).

An end 240a on the inner diameter side of the bottom portion 240 of the clutch hub 24 is welded to the base portion 410 of the sun gear 41, and the sun gear 41 and the clutch hub 24 are coupled to each other in a state where relative rotation in the circumferential direction around the rotation axis X is restricted.

As shown in fig. 2, when viewed from the direction of the rotation axis X, the spline ridges 241a and the spline valleys 241b on the outer diameter side of the peripheral wall portion 241 of the clutch hub 24 are alternately connected to each other in the circumferential direction around the rotation axis X, and splines are formed on the inner periphery and the outer periphery of the peripheral wall portion 241 in the direction of the rotation axis X.

A plurality of drive plates 21 are spline-fitted to the outer periphery of the peripheral wall portion 241, and the drive plates 21 are provided so as to be movable in the direction of the rotation axis X in a state where relative rotation with the peripheral wall portion 241 in the circumferential direction around the rotation axis X is restricted.

As shown in fig. 1, the driven plate 22 located radially outward of the peripheral wall portion 241 is also provided so as to be movable in the direction of the rotation axis X in a state where relative rotation with the clutch drum 25 in the circumferential direction around the rotation axis X is restricted.

The driven plate 22 and the drive plate 21 of the forward clutch 2 are alternately arranged in the direction of the rotation axis X, and the drive plate 21 is arranged so that the outer diameter side of the drive plate 21 overlaps the inner diameter side of the driven plate 22 as viewed in the direction of the rotation axis X.

The portion where the drive plate 21 and the driven plate 22 overlap each other is pressed in the direction of the rotation axis X by a piston 23 provided on the front cover portion 11 side (right side in the figure).

The piston 23 is displaced in the direction of the rotation axis X by adjusting the hydraulic pressure supplied to the oil chamber R formed between the bottom portion 250 of the clutch drum 25 and the piston. When the piston 23 is displaced in a direction away from the front cover portion 11, the drive plate 21 and the driven plate 22 are pressed and coupled. When the piston 23 is displaced toward the front cover portion 11 side, the coupling of the drive plate 21 and the driven plate 22 is released.

In the forward clutch 2, relative rotation between the drive plate 21 and the driven plate 22 is restricted according to a coupling state caused by pressing the drive plate 21 and the driven plate 22.

Therefore, when the drive plate 21 and the driven plate 22 are in a relatively non-rotatably coupled state, the clutch drum 25 to which the driven plate 22 is spline-fitted is coupled to the carrier 44 of the planetary gear set 4, and the clutch hub 24 to which the drive plate 21 is spline-fitted is coupled to the sun gear 41, so that the sun gear 41 and the carrier 44 of the planetary gear set 4 are coupled so as to be integrally rotatable.

In the spline ridge portion 241a of the peripheral wall portion 241 of the clutch hub 24 on the outer diameter side, an oil hole 242 for guiding the lubricant OL supplied from the inner diameter side of the transmission case 10 to the outer diameter side of the peripheral wall portion 241 is formed to penetrate the spline ridge portion 241a in the radial direction.

As shown in fig. 2, in the peripheral wall portion 241 of the clutch hub 24, the spline ridge portions 241a, in which the oil holes 242 are not provided, are located at predetermined intervals in the circumferential direction around the rotation axis X.

The peripheral wall portion 251 of the clutch drum 25 is also formed with an oil hole 252 for guiding the lubricant OL to the outer diameter side of the peripheral wall portion 251 through the spline ridge portion 251a in the radial direction.

Next, the detailed structure of the drive plate 21 and the driven plate 22 of the forward clutch 2, which is a wet friction engagement device, will be described.

Fig. 3 is a view of the drive plate 21 of the forward clutch 2 as viewed from the direction of the rotation axis X.

Fig. 4(a) is a view of the driven plate 22 of the forward clutch 2 as viewed from the direction of the rotation axis X. Fig. 4(b) is an example of an enlarged view of the groove portion. Fig. 4(c) is another example of an enlarged view of the groove portion.

Fig. 5 is an enlarged view of the area a of fig. 1.

In fig. 3, in order to explain the positional relationship between the drive plates 21 and the driven plates 22 alternately arranged in the direction of the rotation axis X, the driven plates 22 arranged adjacent to the drive plates 21 in the direction of the rotation axis X are shown by virtual lines.

As shown in fig. 3, the drive plate 21 has a base portion 210 provided on the outer diameter side with respect to the rotation axis X, and a tooth portion 211 provided on the inner diameter side. The driven plate 22 has a base portion 220 provided on the inner diameter side with respect to the rotation axis X, and a tooth portion 221 provided on the outer diameter side. The base portion 210 of the drive plate 21 and the base portion 220 of the driven plate 22 overlap as viewed from the direction of the rotation axis X.

The base portion 210 of the drive plate 21 is formed in a ring shape when viewed from the direction of the rotation axis X, and a plurality of tooth portions 211 are provided at predetermined intervals along the entire circumference of the inner circumferential edge 210a of the base portion 210 in the circumferential direction around the rotation axis X. The tooth portion 211 is spline-fitted to the outer periphery of the peripheral wall portion 241 (see fig. 2) of the clutch hub 24.

A spacer material 213 is fixed to the base portion 210 of the drive plate 21. The lining material 213 is, for example, a friction material made of fibers impregnated with a synthetic resin.

The lining material 213 is arc-shaped along the circumferential direction around the rotation axis X, and a plurality of lining materials are arranged at equal intervals in the circumferential direction around the rotation axis X. The lining material 213 is disposed at a position shifted to the outer diameter side from the inner circumferential edge 210a of the base 210.

As shown in fig. 5, the lining material 213 is fixed to the one surface 21a and the other surface 21b of the drive plate 21 in the rotation axis X direction, respectively.

As shown in fig. 4(a), the base portion 220 of the driven plate 22 is formed in a ring shape as viewed from the direction of the rotation axis X, and a plurality of tooth portions 221 are provided along the outer peripheral edge 220a of the base portion 220 at predetermined intervals over the entire circumference in the circumferential direction around the rotation axis X. The tooth portion 221 is spline-fitted to the inner periphery of the peripheral wall portion 251 (see fig. 1) of the clutch drum 25.

As shown in fig. 5, in the forward clutch 2, the plurality of drive plates 21 and driven plates 22 are alternately arranged in the direction of the rotation axis X when viewed in the radial direction, and the drive plates 21 and the driven plates 22 are arranged to face each other in the direction of the rotation axis X.

Specifically, one surface 22a of the driven plate 22 in the rotation axis X direction faces the other surface 21b of the driving plate 21. The base portion 220 on the one surface 22a faces the lining material 213 fixed to the other surface 21 b.

The other surface 22b of the driven plate 22 in the rotation axis X direction faces the one surface 21a of the driving plate 21. The base portion 220 of the other surface 22b faces the lining material 213 fixed to the one surface 21 a.

The inner peripheral edge 220b of the base portion 220 of the driven plate 22 is arranged at substantially the same position in the direction of the rotation axis X as the inner peripheral edge 210a of the base portion 210 of the driving plate 21. The inner peripheral edge 213a of the lining material 213 fixed to the base portion 210 of the drive plate 21 is offset radially from the inner peripheral edge 220b of the base portion 220 of the driven plate 22.

That is, in the base portion 220 of the driven plate 22, the facing portion 220c facing the lining material 213 is provided at a position shifted to the outer diameter side from the inner peripheral edge 220b of the base portion 220, and in the inner diameter portion 220d between the facing portion 220c and the inner peripheral edge 220b of the base portion 220, the lining material 213 is not sandwiched therebetween, but faces the base portion 210 of the driving plate 21.

In the following description, the first surface 21a and the second surface 21b of the drive plate 21 in the rotation axis X direction are also simply referred to as "the surface 21 a" and "the surface 21 b". The first surface 22a and the second surface 22b of the driven plate 22 in the rotation axis X direction are also simply referred to as "surface 22 a" and "surface 22 b".

In fig. 4(a), a groove 223 is formed in the driven plate 22, schematically indicated by cross hatching. The groove 223 is formed on the

entire surfaces

22a and 22b (see fig. 5) of the driven plate 22 including the base 220 and the tooth 221.

Fig. 4(b) and 4(c) show an enlarged view of a part of the groove portion 223 in the region a in fig. 4(a), and the groove portion 223 is formed of a fine hexagonal groove 224 continuously formed over the

entire surfaces

22a and 22b of the driven plate 22.

The hexagonal groove 224 may be formed by a known method such as laser processing or press processing. Since the hexagonal groove 224 is formed in the ring-shaped driven plate 22, for example, in laser processing, as shown in fig. 4(b), the groove width GW of the hexagonal groove 224 can be gradually enlarged from the inner diameter side to the outer diameter side of the rotation axis X.

On the other hand, for example, in the press working, as shown in fig. 4(c), the hexagonal groove 224 may be adjusted to have a constant groove width. The hexagonal size refers to the area of the planar portion surrounded by the hexagonal groove 224. Specifically, the size of the hexagon may be adjusted to increase from the inner diameter side to the outer diameter side of the rotation axis X. In this case, the size of the hexagon may be increased by making the radial width RW of the hexagon constant and making the circumferential width CW of the planar portion increase from the inner diameter side to the outer diameter side.

Fig. 6 is a diagram showing details of the groove 223. Fig. 6(a) is an enlarged view of the hexagonal groove 224 formed in the groove portion 223, and fig. 6(b) is a view showing a branch of the circumferential groove 225a at the corner portion 226. Fig. 6(c) shows the branch of the radial groove 225b at the corner 226. In fig. 6, "circumferential direction" and "radial direction" refer to the circumferential direction and the radial direction around the rotation axis X (see fig. 4).

As shown in fig. 4(b) and 4(c), the hexagonal grooves 224 constituting the groove portions 223 may have different dimensions from the inner diameter side to the outer diameter side, but the hexagonal grooves 224 have the same configuration. Here, the structure of the hexagonal groove 224A shown by a thick line at the center of fig. 6(a) will be described as an example. The hexagonal groove 224A is formed by six grooves 225a to 225c connected at six corners 226. The six grooves 225a to 225c have the same length, and the distances from the center O of the hexagonal groove 224A to the six corners 226 are equidistant. The center O is an intersection of diagonal lines connecting the corners 226, and is located on the surfaces of the

surfaces

22a and 22b of the driven plate 22. In fig. 6(a), although the hexagonal groove 224A is illustrated as a regular hexagon, it is not necessarily a strict regular hexagon, and there is an allowable dimensional error. As shown in fig. 4(b) and 4(c), when the size is adjusted from the inner diameter side to the outer diameter side, both regular hexagons and non-regular hexagons may be included.

The hexagonal groove 224A has a pair of

circumferential grooves

225a, 225a extending in the circumferential direction of the rotation axis X and adjacent in the radial direction of the rotation axis X. One end (left side in the figure) and the other end (right side in the figure) of the pair of

circumferential grooves

225a, 225a are connected by

radial grooves

225b, 225c extending in a zigzag shape with respect to a line segment parallel to the radial direction, respectively.

In this way, the hexagonal groove 224A is connected to each other by the ends of the

circumferential grooves

225a, 225a and the

radial grooves

225b, 225c, forming one groove in which grooves extending in different directions communicate.

The hexagonal groove 224A is adjacent to six other hexagonal grooves 224 in the radial direction and the circumferential direction, but shares a circumferential groove 225a with the hexagonal groove 224 adjacent in the radial direction, and shares any of the

radial grooves

225b and 225c with the hexagonal groove 224 adjacent in the circumferential direction.

In addition, the hexagonal groove 224A shares a corner 226 with two hexagonal grooves 224 adjoining in the radial or circumferential direction. Thus, all the grooves constituting the hexagonal groove 224 are branched at the corner 226 to communicate with the other grooves.

For example, as shown in fig. 6(b), the circumferential groove 225a is branched into

radial grooves

225b, 225c at the corner 226. As shown in fig. 6(c), when the radial groove 225b reaches the corner 226, the radial groove 225c and the circumferential groove 225a branch off. Although not shown, when the radial groove 225c reaches the corner 226, the radial groove 225b and the circumferential groove 225a branch off.

The dimensions of the hexagonal grooves 224 are not limited, and the circumferential groove 225a and the

radial grooves

225b and 225c may have a length of 120 μm, a groove depth of 20 μm, and a groove width of 50 μm, respectively.

As shown in fig. 4(a), the hexagonal grooves 224 having the grooves 225a to 225c and the corner portions 226 are formed continuously over the

entire surfaces

22a and 22b of the driven plate 22, and the driven plate 22 is in a state in which the grooves extending in the radial direction and the circumferential direction are uniformly distributed.

As described above, in the forward clutch 2, the piston 23 shown in fig. 1 presses the drive plate 21 and the driven plate 22 from the rotation axis X direction, whereby the drive plate 21 and the driven plate 22 come into contact with each other and are coupled by the generated frictional force.

Specifically, the lining material 213 fixed to the

surfaces

21a and 21b (see fig. 5) of the drive plate 21 is pressed against the

surfaces

22b and 22a of the driven plate 22, and the drive plate 21 and the driven plate 22 are coupled together by friction so as to be non-rotatable relative to each other after passing through a sliding state.

The piston 23 is displaced in a direction away from the drive plate 21 and the driven plate 22, whereby the drive plate 21 and the driven plate 22 are in a released state.

Here, when the coupled state and the released state of the drive plate 21 and the driven plate 22 are switched, the drive plate 21 and the driven plate 22 temporarily form a state of sliding, and are heated.

The forward clutch 2 is provided with a supply structure of the lubricating oil OL. The lubricating oil OL is supplied for friction adjustment and cooling of the drive plate 21 and the driven plate 22.

As shown in fig. 5, the drive plate 21 is spline-fitted to the outer periphery of the peripheral wall portion 241 of the clutch hub 24 of the forward clutch 2, and oil holes 242 penetrating the spline ridge portions 241a in the radial direction of the rotation axis X are provided in the peripheral wall portion 241 of the clutch hub 24.

The lubricating oil OL reaches the inner periphery of the peripheral wall portion 241 from the inner diameter side of the rotation shaft X due to the centrifugal force generated by the rotation of the clutch hub 24, and is supplied to the region Rx where the drive plate 21 and the driven plate 22 are located on the outer diameter side of the peripheral wall portion 241 through the oil holes 242.

The lubricating oil OL supplied to the region Rx reaches the inner peripheral edge 220b of the base portion 220 of the driven plate 22, branches to the surface 22a side and the surface 22b side, and flows from the inner diameter portion 220d of the base portion 220 to the opposing portion 220 c. The lubricant OL is supplied to the lining material 213 facing the facing portion 220c to cool the lining material 213.

Here, as described above, the facing portion 220c is provided at a position shifted to the outer radial side from the inner peripheral edge 220b of the base portion 220, and the lining material 213 is not sandwiched between the facing portions in the inner radial portion 220d, so that the lubricating oil OL easily flows to the facing portion 220c on the outer radial side and is easily supplied to the lining material 213.

The lubricating oil OL finally reaches the outer diameter sides of the drive plate 21 and the driven plate 22, and is supplied from the oil holes 252 (see fig. 1) in which the peripheral wall portion 251 of the driven plate 22 is spline fitted on the inner periphery to the reverse brake 3 (see fig. 1) located radially outward.

Here, when the drive plate 21 and the driven plate 22 are coupled, the lining material 213 is pressed against each other, and thereby the surface pressure received by the

surfaces

22a and 22b of the driven plate 22 is increased, and heat may be generated.

The lubricating oil OL supplied to the

surfaces

22a, 22b of the driven plate 22 is likely to generate polymer due to thermal damage, and the generated polymer or the like may block the pores of the lining material 213. Since the air holes of the lining material 213 are blocked, the missing lubricating oil OL may excessively exist between the driving plate 21 and the driven plate 22. A force trying to push back the lining material 213 acts on the excessive lubricating oil OL, and thereby a phenomenon close to wet skid occurs, which may cause chattering.

Furthermore, the heat generation may also affect the durability of the wet friction coupling device.

Fig. 7 is a graph showing the μ V characteristic of the driven plate 22.

The μ V characteristic represents a friction coefficient (μ) between the driven plate 22 and the lining material 213 corresponding to a relative velocity (V) between the driven plate 22 and the lining material 213. In fig. 7, the solid line indicates the initial gradient of the μ V characteristic, and the broken line indicates the gradient after degradation.

As is apparent from the graph of fig. 7, the wet friction coupling device deteriorates with time, and such deterioration with time is promoted by a temperature increase due to heat generation. Here, by applying the configuration of the embodiment, since the temperature rise can be alleviated, the deterioration rate can be alleviated, and the durability of the wet friction coupling device can be improved.

As shown in fig. 4, in the embodiment, the groove 223 is formed over the

entire surfaces

22a and 22b of the driven plate 22.

Therefore, when the lining material 213 is pressed against the

surfaces

22a, 22b of the driven plate 22, the lubricating oil OL adhering to the surface of the driven plate 22 enters the groove portions 223 from the surface as shown by the arrows in fig. 6 (a). Thus, the lubricating oil OL does not excessively exist between the drive plate 21 and the driven plate 22.

The groove portion 223 is formed continuously on the

surfaces

22a and 22b of the driven plate 22, and is constituted by a hexagonal groove 224, and each hexagonal groove 224 shares any of the circumferential groove 225a and the

radial grooves

225b and 225c with the other hexagonal grooves 224, whereby the entire groove portion 223 communicates in the radial direction and the circumferential direction of the driven plate 22.

Thus, the lubricant oil OL entering the groove portion 223 flows from the inner diameter side to the outer diameter side of the rotation shaft X by the centrifugal force generated by the rotation of the clutch hub 24, and is easily discharged to the reverse brake 3 (see fig. 1) located radially outward of the forward clutch 2.

The lubricating oil OL flows from the inner diameter side to the outer diameter side of the rotation shaft X by the centrifugal force generated by the rotation of the clutch hub 24, and also flows in the circumferential direction. Since the hexagonal groove 224 has the circumferential groove 225a formed in the circumferential direction, the lubricating oil OL flowing in the circumferential direction is obtained by the circumferential groove 225a, and further flows easily to the outer diameter side of the driven plate 22 through the

radial groove

225b or 225c communicating with the circumferential groove 225 a.

The circumferential groove 225a and the

radial grooves

225b and 225c constituting the hexagonal groove 224 communicate with the other grooves at the corner 226. For example, as shown in fig. 6(b), when the lubricating oil OL flowing through the circumferential groove 225a and the radial groove 225b reaches the corner portion 226, the lubricating oil OL flows into the radial groove 225c on the outer radial side. As shown in fig. 6(c), when the lubricating oil OL flowing through the radial groove 225b reaches the corner portion 226, the lubricating oil OL flows into the circumferential groove 225a and the radial groove 225c while being branched by the corner portion 226. Thus, the lubricating oil OL flowing in each groove is merged at the corner portion 226 or branched by being branched by the corner portion 226, whereby the fluidity of the lubricating oil OL is increased.

In the case immediately after the vehicle starts running or the like, the fluidity tends to be poor because the lubricating oil OL is low in temperature, but because the fluidity is thus improved in the hexagonal groove 224, the lubricating oil OL is less likely to excessively exist between the drive plate 21 and the driven plate 22.

As shown in fig. 4(a), the groove 223 is formed over the

surfaces

22a and 22b of the driven plate 22, and is formed continuously not only on the facing portion 220c of the base portion 220 facing the lining material 213 but also on the outer diameter side of the facing portion 220c including the tooth portion 221. This makes it easy for the lubricating oil OL supplied to the opposing portion 220c to be discharged to the outer diameter side and to be supplied to the reverse brake 3 on the outer diameter side of the forward clutch 2.

As shown in fig. 4(b), when the hexagonal groove 224 is formed by increasing the groove width GW from the inner diameter side to the outer diameter side of the rotation axis X, the width of the hexagonal groove 224 formed in the tooth portion 221 is wider than the width of the hexagonal groove 224 formed in the base portion 220, and the lubricant OL is more easily discharged.

As shown in fig. 4(c), in the hexagonal sizing, when the radial width RW is adjusted to be constant and the circumferential width CW is increased from the inner diameter side to the outer diameter side, the circumferential corner 226 is not enlarged on the outer diameter side. Therefore, even when the drive plate 21 and the driven plate 22 are coupled, the circumferential corner portion 226 can ensure the effect of shunting and discharging the lubricating oil OL on the outer diameter side.

As shown in fig. 5, the lubricant OL flows from the inner diameter portion 220d of the driven plate 22 to the facing portion 220c facing the lining material 213, but the groove portion 223 is formed continuously from the inner diameter portion 220d to the facing portion 220 c. Therefore, the lubricant OL entering the groove portion 223 of the inner diameter portion 220d easily flows to the facing portion 220c on the outer diameter side, and the lubricant OL is easily supplied to the lining material 213 of the facing portion 220 c.

As described above, in the forward clutch 2 (wet friction coupling device) of the embodiment,

(1) having a drive plate 21 (first friction member) and a driven plate 22 (second friction member),

the driven plate 22 has a groove 223 formed on

surfaces

22a and 22b (front surface) of the base portion 220 facing the drive plate 21.

The groove portions 223 improve the cooling performance of the lubricating oil OL supplied between the drive plate 21 (first friction member) and the driven plate 22 (second friction member).

For example, in the forward clutch 2, the piston 23 presses the drive plate 21 and the driven plate 22 to generate friction, and the drive plate 21 and the driven plate 22 are coupled to transmit a rotational driving force.

When the lubricating oil OL exists excessively between the drive plate 21 and the driven plate 22, a phenomenon close to wet skid occurs, possibly resulting in chattering.

In the case where the lining material 213 is provided on the drive plate 21, when the surface pressure between the facing

surfaces

22a and 22b of the lining material 213 and the driven plate 22 is increased, heat is generated, and the lubricating oil OL is easily damaged by heat to generate a polymer. The polymer or the like may block the pores of the liner material 213. Alternatively, in a state where the lining material 213 is new, the porosity of the lining material 213 may be insufficient, and the pores may be insufficient.

Because the air holes are clogged or the porosity is insufficient, the missing lubricating oil OL excessively exists between the drive plate 21 and the driven plate 22, and a force trying to push back the lining material 213 acts, whereby a phenomenon close to wet road slip occurs, and chattering may occur.

In the embodiment, since the groove portion 223 is formed on the surface of the base portion 220 of the driven plate 22, the lubricating oil OL existing between the driven plate 22 and the drive plate 21 enters the groove portion 223, thereby improving oil drainage even in a state where there is relative rotation. Thus, the lubricating oil OL does not excessively exist between the drive plate 21 and the driven plate 22, and the phenomenon close to wet skid can be suppressed, so that chattering can be suppressed.

Further, since the lubricating oil OL flows through the groove portions 223 formed on the surface of the base portion 220 of the driven plate 22, heat generation of the driven plate 22 can be suppressed, and generation of polymer due to thermal damage can be fundamentally suppressed, so that clogging of pores of the lining material 213 by the polymer can be suppressed. Since the pores of the lining material 213 are less likely to be blocked, the lubricating oil OL between the drive plate 21 and the driven plate 22 is less likely to be excessive, and the urging force trying to push back the lining material 213 can be suppressed.

As described above, the groove 223 formed in the surface of the base portion 220 of the driven plate 22 can improve the cooling performance of the friction surface and the oil drainage performance of the friction portion, and thus can suppress the generation of the chattering, and can improve the durability of the drive plate 21 and the driven plate 22.

In the above embodiment, the groove portions 223 are formed integrally on the one surface 22a and the other surface 22b of the driven plate 22, but the present invention is not limited to this, and the groove portions 223 may be formed only on the base portion 220 of the driven plate 22 facing the base portion 210 of the drive plate 21.

In the embodiment, the first friction member is associated with the drive plate 21 and the second friction member is associated with the driven plate 22, but the first friction member may be the driven plate 22 and the second friction member may be the drive plate 21. In this case, the lining material may be provided on the driven plate 22 side and the groove may be provided on the driving plate 21 side.

(2) The base portion 220 is provided on the inner diameter side of the driven plate 22, and a groove portion 223 communicating with the groove portion 223 formed on the surface of the base portion 220 is provided on the surface on the outer diameter side of the driven plate 22.

Since the groove portion 223 is also formed continuously in the tooth portion 221 on the outer diameter side of the base portion 220, the lubricant OL is easily discharged to the outer diameter side by the centrifugal force.

(3) The groove 223 formed on the outer diameter side surface is wider than the groove 223 formed on the surface of the base 220.

By making the groove width GW of the groove portion 223 provided in the tooth portion 221 on the outer diameter side wider than the groove portion 223 of the base portion 220 on the inner diameter side, the lubricant OL is easily discharged to the outer diameter side.

(4) The lining material 213 (friction lining material) is provided on the surface of the drive plate 21, the facing portion 220c facing the lining material 213 is provided on the outer diameter side of the base portion 220 of the driven plate 22, and the groove portion 223 is formed continuously from the inner diameter side to the outer diameter side of the base portion 220.

When the drive plate 21 and the driven plate 22 are coupled, the driven plate 22 is pressed against the lining material 213 fixed to the base portion 210 of the drive plate 21 at the opposed portion 220c on the outer diameter side of the base portion 220. The surface pressure between the lining material 213 and the driven plate 22 increases, and heat is easily generated. By forming the groove portion 223 continuously from the inner diameter portion 220d to the facing portion 220c of the base portion 220 of the driven plate 22, the lubricating oil OL supplied from the inner diameter portion 220d is easily supplied to the facing portion 220c, and the lining material 213 is easily cooled.

(5) The groove portion 223 is formed by a hexagonal groove 224 which is a polygonal groove having a plurality of corner portions 226.

The lubricating oil OL flows radially from the inner diameter side to the outer diameter side of the driven plate 22 by the centrifugal force generated by the rotation of the clutch hub 24, but flows circumferentially by the centrifugal force because the driven plate 22 rotates. By making the groove portion 223 a hexagonal groove 224 which is a polygon, grooves extending in different directions can be provided, and the lubricating oil OL flowing in the radial direction and the circumferential direction can be easily obtained. Further, by forming the hexagonal groove 224, the lubricating oil OL can uniformly enter the groove at each corner 226, and the oil drainage performance can be improved.

In the embodiment, the hexagonal groove 224 is exemplified as a polygonal groove, but is not limited thereto. Other polygons such as a triangle or a quadrangle may be used.

(6) The hexagonal grooves 224 are formed continuously on the surface of the base portion 220 of the driven plate 22, and the corner 226 of each hexagonal groove 224 is shared with the corner 226 of another adjacent hexagonal groove 224.

By forming the hexagonal groove 224 continuously on the one surface 22a and the other surface 22b of the driven plate 22, the area into which the lubricating oil OL enters can be increased. Since the lubricant OL flows from the inner diameter side to the outer diameter side of the driven plate 22 through the hexagonal groove 224 formed continuously, the lubricant OL is easily discharged to the rear brake 3.

When the lubricant OL entering each groove constituting the hexagonal groove 224 reaches the corner portion 226, the lubricant OL is branched by the corner portion 226 and branched to another groove, or is merged at the corner portion 226, thereby improving the fluidity of the lubricant OL. Although the fluidity of the lubricating oil OL is reduced at low temperature when the transmission starts operating, the fluidity can be improved even at the start of operating by providing the corner portion 226.

In order to form the hexagonal groove 224 continuously on the surface of the base 220, for example, the hexagonal groove 224 is formed to have a larger area on the hexagonal outer diameter side than on the inner diameter side of the driven plate 22. Specifically, the hexagon gradually increases from the inner diameter side to the outer diameter side.

(7) The hexagonal shape of the hexagonal groove 224 may increase the circumferential width CW around the rotation axis X from the inner diameter side to the outer diameter side.

Accordingly, since the circumferential corner 226 of the hexagonal groove 224 does not expand on the outer diameter side, the effect of the corner 226 shunting and discharging the lubricating oil OL can be ensured when the drive plate 21 and the driven plate 22 are coupled.

(8) In the embodiment, a hexagonal groove 224 is used as the polygonal groove.

By forming the hexagonal groove 224, it is possible to arrange grooves extending in different directions without a gap on the one surface 22a and the other surface 22b of the driven plate 22, and it is easy to cause the lubricating oil OL to enter the grooves and to discharge the lubricating oil OL that has entered the grooves to the rear stopper 3.

(9) The hexagonal groove 224 is constituted by a pair of

circumferential grooves

225a, 225a extending in the circumferential direction around the rotation axis X and adjacent in the radial direction of the rotation axis X, and a plurality of

radial grooves

225b, 225c connecting radially opposite ends of the pair of

circumferential grooves

225a, 225a to each other.

By providing the circumferential groove 225a, the lubricating oil OL that moves in the circumferential direction by receiving the centrifugal force generated by the rotation of the drive plate 21 and the driven plate 22 easily enters the groove, and by connecting the circumferential groove 225a to the

radial grooves

225b and 225c, the lubricating oil OL obtained by the circumferential groove 225a easily flows to the outer diameter side through the

radial grooves

225b and 225c and is discharged from the driven plate 22.

(10) The groove 223 formed on the surface of the base portion 220 of the driven plate 22 is formed on the entire surface of the base portion 220.

By forming the groove 223 on the entire surface of the base 220, processing can be performed more easily than in the case of local formation.

< first modification >

Fig. 8 is a diagram illustrating the structure of the groove 223 according to the first modification.

Although the case where the hexagonal groove 224 described in the embodiment has the circumferential groove 225a (see fig. 6) along the circumferential direction has been described, the present invention is not limited to this.

As shown in fig. 8, the hexagonal grooves 227 of the first modification example are arranged with the directions of the hexagonal grooves 224 of the embodiment changed.

The hexagonal groove 227 has a pair of

radial grooves

227a, 227a extending in the radial direction of the rotation axis X and adjacent in the radial direction of the rotation axis X. The pair of

radial grooves

227a, 227a are connected by

circumferential grooves

227b, 227c extending in a zigzag manner with respect to a line segment parallel to the circumferential direction.

The hexagonal groove 227 of the first modification also has grooves extending in different directions, and thus the lubricating oil OL flowing in the radial direction and the circumferential direction is easily obtained.

< second modification >

Fig. 9 is a diagram illustrating a structure of the groove 223 according to the second modification.

As shown in fig. 9, the groove portion 223 may be formed of a circular groove 228. The circular groove 228 is a circular groove as viewed in the direction of the rotation axis X (see fig. 4 a), and is formed continuously over the

entire surfaces

22a and 22b of the driven plate 22, similarly to the hexagonal groove 224. As shown in fig. 9, the circular groove 228 has a portion along the radial direction of the driven plate 22 and a portion along the circumferential direction, and shares a part of the groove with another circular groove 228 adjacent in the radial direction and the circumferential direction.

As described above, in the second modification example

(11) The groove portion 223 is formed by a circular groove 228 which is a circular groove when viewed from the rotation axis X direction.

The lubricating oil OL flows radially from the inner circumferential side to the outer circumferential side of the drive plate 21 and the driven plate 22, but is subjected to a centrifugal force generated by the rotation of the drive plate 21 and the driven plate 22 and moves in the circumferential direction. By providing the circular groove 228 on the

surfaces

22a, 22b of the driven plate 22, the lubricating oil OL flowing in the radial and circumferential directions easily enters the groove. In addition, since the circular groove 228 is formed equidistantly from the center O, the lubricant OL adhering to the surface easily enters the circular groove 228 uniformly.

(12) The circular grooves 228 are formed continuously on the surface of the base portion 220 of the driven plate 22, and a part of each circular groove communicates with an adjacent circular groove.

By forming the circular groove 228 continuously on the

surfaces

22a and 22b of the driven plate 22, the area into which the lubricating oil OL enters can be increased, and the lubricating oil OL entering the groove can be discharged from between the drive plate 21 and the driven plate 22 through the communicating groove, so that the oil discharge performance can be improved. As in the embodiment, the circular groove 228 may be formed on the entire surface of the base 220, thereby facilitating the processing.

In the above-described embodiment and the first and second modifications, the example in which the drive plate 21 is fitted to the clutch hub 24 provided on the inner diameter side of the rotation axis X and the driven plate 22 is fitted to the clutch drum 25 provided on the outer diameter side of the rotation axis X has been described, but the present invention is not limited thereto. For example, the drive plate 21 may be fitted to the outer-diameter-side rotating body of the rotation shaft X, and the driven plate 22 may be fitted to the inner-diameter-side rotating body of the rotation shaft X.

In the above-described embodiment and the first and second modifications, the example in which the wet friction engagement device of the present invention is applied to the forward clutch 2 has been described, but the application example is not limited to this. The present invention can be applied to, for example, the reverse brake 3 and a lock-up clutch of a torque converter of a vehicle. The lockup clutch of the torque converter may be a multi-plate or a single plate, as in the forward clutch 2.

Fig. 10 is a diagram showing the structure of the torque converter 100. Fig. 10 shows an example in which the lockup clutch 112 is a single plate.

As shown in fig. 10, the torque converter 100 includes: a pump impeller 102 coupled to an input shaft (not shown) to which a driving force is input via a front cover 101, a turbine impeller 105 coupled to an output shaft 103 via a turbine hub 104, a stator impeller 108 fixed to a case 107 via a one-way clutch 106, a torque converter oil chamber 109 housing the pump impeller 102 and the turbine impeller 105, a bearing 110, a working oil inflow passage 111a, and a working oil outflow passage 111 b.

The lockup clutch 112 includes: a lock-up piston 112a, and a torsional damper 112b that is circumferentially engaged with the lock-up piston 112a and spline-coupled to the turbine hub 104. A facing surface of the outer diameter portion of the lock piston 112a facing the front cover 101 is provided with a lining material 117. When the lockup clutch 112 is operated, the lining material 117 is pressed against and coupled to the front cover 101, and directly transmits the driving force input from an input shaft, not shown, to the output shaft 103.

A groove 118 is provided on a surface of the front cover 101 facing the lockup clutch 112. The groove portion 118 may be formed by continuously forming a hexagonal groove described in the embodiment or the first modification or a circular groove described in the second modification.

The lock-up clutch 112 is supplied with the lubricating oil OL via the oil path 103b and the like. The lockup clutch 112 also temporarily enters a slip state and generates heat when switching between engagement and disengagement, as in the case of the forward clutch 2. Although the lubricating oil OL provides the lock-up clutch 112 with the pressure release and cooling functions, as in the embodiment, when the lubricating oil OL is overheated, the oil is polymerized, and chattering may occur due to clogging of pores of the lining material with the polymerized oil, or the like.

Therefore, the same effects as those of the embodiment can be obtained by providing the groove portion 118 on the surface of the front cover 101 facing the lining material 117 of the lockup clutch 112, as in the embodiment. That is, the first friction member of the wet friction engagement device of the present invention may be the lock-up clutch 112, and the second friction member may be the front cover 101. The groove 118 may be provided only in a portion of the front cover 101 facing the lining material 117, or may be provided over the entire surface.

The first friction member may be the front cover 101, and the second friction member may be the lock-up clutch 112. That is, the lining material 117 may be provided on the front cover 101 side, and the groove 118 may be provided on the surface of the opposite lock-up clutch.

Description of the reference numerals

2a forward clutch; 21 driving a board; 21a side; 21b, the other side; 210a base; 211 a tooth part; 213a lining material; 213a inner circumference; 22a driven plate; 22a side; 22b and the other side; 220a base portion; 220a outer peripheral edge; 220b inner peripheral edge; 220c opposite parts; 220d inner diameter part; 221 tooth parts; 223 a groove part; 224, 224A, 227 hexagonal grooves; 225a circumferential groove; 225b, 225c radial slots; 227a radial slots; 227b, 227c circumferential grooves; 228 a circular groove; 23 a piston; a 24 clutch hub; 240 bottom part; 241 peripheral wall part; 241a spline peak part; 241b spline valleys; 242 oil holes; 25a clutch drum; 250 bottom part; 251a peripheral wall portion; 251a spline crest portion; 251b spline valleys; 252 oil holes; 3, backing off the brake; 31 a drive plate; a 32 driven plate; 33 a piston; 4a planetary gear set; 41a sun gear; 42 pinion gear; 43 a ring gear; 44 a planet carrier; 5a forward and backward switching mechanism; 10a gearbox; 11a front cover part; 100 a torque converter; 101 a front cover; 102 a pump impeller; 103 an output shaft; 104 a turbine hub; 105 a turbine wheel; 106 one-way clutch; 107 a box body; 108 a stator impeller; 109 a torque converter oil chamber; 110 bearings; 111 working oil inflow path; 111b working oil outflow path; 112 lock-up clutch; 112a lock the piston; 112b torsional dampers; 113b oil passage; 117 a liner material; 118 a slot portion; an O center; an OL lubricating oil; an R oil chamber; the X axis of rotation.

Claims

1. A wet friction coupling device, characterized in that,

comprising: a first friction member and a second friction member,

2. Wet friction coupling device as claimed in claim 1,

the base is provided on the inner diameter side of the second friction member,

the second friction member has a groove portion on an outer diameter side surface thereof, the groove portion communicating with the groove portion formed on the surface of the base portion.

3. Wet friction coupling device according to claim 2,

the groove portion formed on the outer diameter side surface has a width larger than that of the groove portion formed on the surface of the base portion.

4. Wet friction coupling device as claimed in claim 1,

a friction lining material is provided on the surface of the first friction member,

an opposing portion that opposes the friction lining material is provided on the outer diameter side of the base portion of the second friction member, and the groove portion is formed continuously from the inner diameter side to the outer diameter side of the base portion.

5. Wet friction coupling device as claimed in claim 1,

the groove portion is formed by a polygonal groove having a plurality of corner portions.

6. Wet friction coupling device as claimed in claim 5,

the polygonal grooves are formed continuously on the surface of the base of the second friction member, and corners of each polygonal groove are shared with corners of adjacent polygonal grooves.

7. Wet friction coupling device as claimed in claim 6,

the polygon on the outer diameter side is larger than the polygon on the inner diameter side of the second friction member.

8. Wet friction coupling device as claimed in claim 7,

the polygon shape gradually increases from the inner diameter side to the outer diameter side.

9. Wet friction coupling device as claimed in claim 8,

the polygon has a circumferential width around the rotation axis that increases from the inner diameter side to the outer diameter side.

10. Wet friction coupling device as claimed in claim 6,

the polygonal grooves are hexagonal grooves.

11. Wet friction coupling device as claimed in claim 10,

the hexagonal groove is constituted by a pair of circumferential grooves extending in a circumferential direction around a rotating shaft and adjacent in a radial direction of the rotating shaft, and a plurality of radial grooves connecting ends of the pair of circumferential grooves opposed in the radial direction to each other.

12. Wet friction coupling device as claimed in claim 1,

the groove portion is formed by a circular groove as viewed from the rotation axis direction.

13. Wet friction coupling device as claimed in claim 12,

the circular grooves are formed continuously on the surface of the base of the second friction member, and a part of each circular groove communicates with an adjacent circular groove.

14. Wet friction coupling according to any one of claims 1 to 13,

the groove portion formed on the surface of the base portion is formed on the entire surface of the base portion.