Friction plate

Abstract

ProblemTo provide a friction plate with reduced drag torque. SolutionThe friction plate is formed with oil grooves having the sectorial shapes spreading toward the inner circumference and the perimeter. The adjacent edges of the friction material segments are provided with the perimeter side vertex and the inner circumference side vertex respectively. The sectorial oil groove opening toward the perimeter side from the inner circumferential side vertexes can discharge a lube oil to the perimeter side efficiently by a centrifugal force. Also, owing to the sectorial oil groove opening toward the inner circumference side from the perimeter side vertexes, a lube oil can be made to run aground onto the friction material segments due to a centrifugal force, thus, reducing the drag torque markedly compared with the conventional plates.

Claims

1. A friction plate in which a plurality of friction material segments are fixed in a circumferential direction of an annular plate, and radial oil grooves are formed between adjacent friction material segments, wherein each of said friction material segments is provided with radially extending side edges and a vertex formed on each radially extending side edge, vertexes of adjacent side edges of the friction material segments facing with each other, each oil groove forming sectors spreading both outwardly and inwardly from said facing vertexes, and said facing vertexes for each oil groove being composed of an inner circumference side vertex located in an inner circumference side from a radially intermediate point of the oil groove or a perimeter side vertex located in a perimeter side from the radially intermediate point.

2. The friction plate according to claim 1 in which said oil grooves having said facing inner circumference side vertexes and said another oil grooves having said facing perimeter side vertexes are alternatingly located in at least a part of the whole circumference.

3. The friction plate according to claim 1 in which each of the sectorial shapes of the oil grooves has an opening angle in the range of 10 degrees to 30 degrees.

4. The friction plate according to claim 2 in which each of sectorial shapes of the oil grooves has an opening angle in the range of 10 degrees to 30 degrees.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a partial front view of the friction plate according to one exemplary embodiment.

(2) FIG. 2 is an enlarged view of a principal part of FIG. 1.

DETAILED DESCRIPTION

(3) Hereinafter, with reference to FIGS. 1 and 2, an exemplary embodiment of the present disclosure will be explained. However, the present disclosure is not limited to this embodiment. In addition, although the friction plate of the present disclosure is used for a wet type clutch, since a fundamental structure of a wet type clutch is well known, a detailed demonstration accompanied by illustration of a wet type clutch itself is omitted.

(4) As shown in FIG. 1, the friction plate 10 of the illustrated embodiment is comprised of an annular plate 12, and two or more friction material segments 14 are fixed in the circumferential direction on the plate 12. The friction material segments 14 are also fixed on the back side of the plate 12 in the same arrangement. The oil groove 16 is formed by the adjacent friction material segments 14 passing from the inner circumference side to the perimeter side of the plate 12. The plate 12 and the friction material 14 can be made in a conventional manner using a well-known technology. In addition, instead of bonding the frictional material segments on the plate 12 as illustrated, a piece of an annular friction material may be bonded on the plate 12 and oil grooves 16 can be formed by means of pressing operation.

(5) Each oil groove 16 forms a pair of sectors which spread in both directions, namely, toward the side of inner circumference and the perimeter. In FIG. 1, in the position shown by A, the oil groove 16a formed by the adjacent friction material segments 14 has sectors, namely, the larger, inner one and the smaller outer one. Also, in the position shown by B, the oil groove 16b formed by the adjacent friction material segments 14 has sectors, namely, the larger, outer one and the smaller, inner one. The oil groove 16a and the oil groove 16b do not necessarily need to be arranged in the direction of a circumference alternatingly as illustrated. For example, oil grooves of other contours may be provided in addition to the oil groove 16a and the oil groove 16b, and the oil groove 16a or oil groove 16b may be repeated in the direction of a circumference by appropriately modifying the shapes of the friction material segments. However, it may be preferable to arrange alternately the perimeter side vertexes 14a and the inner circumference side vertexes 14b (as shown in FIG. 2) in the circumferential direction so as to dispose the oil groove 16a and the oil groove 16b in the circumferential direction alternately, as it serves to arrange the oil groove 16a and 16b as many as possible on the plate 12.

(6) When the wet type clutch in which the friction plate 10 is applied is in a disengagement state, the lubricating oil dragged by the mating plate (illustration omitted) moves to the perimeter side by a centrifugal force, being dragged in the circumferential direction of the friction plate 10. At this time, owing to the configuration of the oil groove 16a where the width narrows toward the perimeter side, the lubricating oil passing through the oil groove 16a overflows and runs aground on the friction material segment 14 causing a separating force. On the other hand, the lubricant which passes through the oil groove 16b, may be efficiently discharged toward the perimeter side owing to the configuration of the oil groove 16b spreading outwardly. For this reason, while the lube oil runs aground onto the friction material segments 14 making the content of air increase, the lube oil can be efficiently discharged to the perimeter side of the friction plate 10, thus, remarkably reducing the drag torque.

(7) As shown in FIG. 2, the sectors of the oil groove 16a formed by the adjacent edges of the friction material segments 14 are characterized by the perimeter side vertexes 14a. On the other hand, the sectors of the oil groove 16b formed by the adjacent edges of the friction materials 14 are characterized by the inner circumference side vertexes 14b. When the radial dimension h of the oil groove 16 formed by the adjacent friction material segments 14 is bisected in the radial direction, the vertex located in the perimeter side is the perimeter side vertex 14a, and the vertex located in the inner circumference side is the inner circumference side vertex 14b. It may be necessary that the facing perimeter side vertexes 14a and inner circumference side vertexes 14b should not be in contact with each other. On the other hand, a pair of the friction material segments 14 having the facing perimeter side vertexes 14a and the inner circumference side vertexes 14b can be pertinently disposed in the range of 0.5 degree-3.5 degrees about the center of the plate 12. It is because the advantages of the present disclosure cannot fully be demonstrated if the adjacent friction material segments 14 having the perimeter side vertex 14a or the inner circumference side vertex 14b separate too much. In short, the appropriate center angle will depend upon the diameter of the plate 12.

(8) It has been found that against the radial dimension h of the oil groove 16 measured from the inner circumference, the location of the perimeter side vertex 14a can be 60%-80% in order that the lube oil can run aground onto the friction material 14 with ease. Likewise, when the inner circumference side vertex 14b is located within the limits of 20%-40% of the dimension h, it can make a lube oil discharge smoothly. The perimeter side vertex 14a and the inner circumference side vertex 14b need to be formed so that they may face with each other on the adjacent friction material segments 14, but the vertexes do not need to be sharp but may be somewhat roundish.

(9) Moreover, the sectorial opening angles a, b, c and d as regards the perimeter side vertex 14a or the inner circumference side vertex 14b can be within the limits of 10 degrees-30 degrees. By so doing, it is possible to produce friction plates suited to improve the discharging efficiency of a lube oil, and to cause a lube oil to run aground easily onto the friction materials.

(10) Furthermore, provision of the perimeter side vertex 14a and the inner circumference side vertex 14b on a pair of the radially extending edges of a friction material segment sandwiched by the adjacent oil grooves 16a and 16b may be desirable, since by so doing, the oil groove 16a and the oil groove 16b can be arranged alternatingly over the whole annular surface of the plate 12.

(11) Only one embodiment of the present disclosure is explained hereinabove. It is to be noted, however, that the oil grooves 16a and 16b need to be formed partly on the friction plate 10, and in the remaining part, oil grooves of other contours (not shown) may be provided.

(12) According to the present disclosure, as explained above, the discharging efficiency of a lube oil can be increased, and also the content of air of a lube oil can be caused to increase significantly so that friction plates with less drag torque can be provided.

EXPLANATION OF REFERENCES

(13) 10 Friction plate 12 Plate 14 Friction material segment 14a Vertex (perimeter side vertex) 14b Vertex (inner circumference side vertex) 16 Oil groove