Dynax Corporation

Dynac Corporation

Norio Takakura

Yuzuru Sanbongi

Ryo Ohashi

Han Zhi-peng

Jin Takahashi

Shahjada Ahmed Pahlovy

Akihito Oikawa

Shintaro Kameya

Han Zhi Peng

Problem&#x2014;To provide a friction plate with reduced drag torque. Solution&#x2014;The 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.

Friction plate

For a friction plate, when a friction clutch is in a disengagement state, a lubricating oil flowing from an outer circumferential oil groove into an inner circumferential side and rides onto a first segment of a first friction material set. For the friction plate, the lubricating oil flowing from an inner circumferential oil groove into the outer circumferential side rides onto a third segment of a second friction material set.

A friction mating member is fabricated by providing a surface of a base member with a hard coating having a load point displacement characteristic in which the elastic range, that is, the ratio of elastic deformation to maximum indentation depth, is at least 50% in a load range from 1 to 50 mN. The friction mating member is capable of coping with both an increasing friction coefficient in a high-speed range and decreasing friction coefficient in a low-speed range, without being affected by the type and deterioration of the lubricating oil. The friction mating member maintains an m-V characteristic having a positive gradient over a long period of use. Thus, the friction mating member solves problems attributable to noise and vibration.

Hard-faced friction mating member

An advantage of the present invention is the provision of a friction material having a porous structure and a large static coefficient of friction, that is made to have a porous structure so as to improve heat resistance but which does not exhibit time-varying characteristics in friction at the beginning of engagement. A friction material 120 is provided on the surface thereof with small holes 160 each of which is 0.02 mm.sup.2 to 0.2 mm.sup.2 in size and whose area ratio to the whole surface area of the friction material 120 is not less than 5% and whose ratio of depth to the thickness of the friction material 120 is not less than 20% and holds oil in the small holes 160. Even if the friction material 120 is made to have a porous structure, an oil film is always formed on a friction sliding surface by the oil held in the small holes 160 to reduce a shearing force produced when an associated plate shears the oil film, thereby preventing an increase in the dynamic coefficient of friction, which can prevent a speed change shock.

Wet-type friction plate having small holes on the surface

In a clutch for an automatic transmission having a unilateral clutch disc construction in which outwardly toothed plates are interleaved with inwardly toothed plates, and the plates have friction faces only on one side, the inner peripheries of the outwardly toothed plates and the outer peripheries of the inwardly toothed plates have circumferentially spaced notches. These notches prevent distortion due to thermal expansion occurring when the clutch discs are unevenly engaged.

Unilateral disc-type friction clutch with thermal distortion avoidance

A friction engagement device has single-faced externally toothed disks interleaved with single-faced internally toothed disks which are engageable by an annular piston. The thickness of the externally toothed disks is less than the thickness of the internally toothed disks for improved heat dissipation performance.

Single-faced disk type friction engagement device of equalized

A friction plate for a friction engagement device has a pattern of grooves in the surface thereof. In one embodiment, radial grooves are inclined from the inner edge of the plate to the outer edge which divide the plate into friction material segments. A pair of radially spaced connecting grooves traverse each segment to connect the radial grooves which define the segment, and are staggered radially from the pairs of connecting grooves of the adjacent segments, so that the grooves of adjacent pairs alternate in radial location across the radial groove which divides them. In another embodiment, tangential grooves form a regular polygon inscribing the outer edge of the friction plate. In both embodiments, oil traverses the surface of the plate from the inner diameter edge to the outer diameter edge by a serpentine route alternating between the radial grooves and the connecting or tangential grooves.

Friction plate for high oil passage and cooling

A groove structure for a wet-type friction engaging element has an approximately U-shaped cross-sectional form in which both corners of a bottom surface are deeper than an intermediate section.

Groove structure of wet-type friction engaging element

Wet-type friction members in an automatic transmission are provided with sets of grooves which diverge from each other, or with grooves which increase in width as they approach an edge of the frictional surface and which are rearwardly inclined in relation to the direction of rotation of the member which engages the grooved frictional surface. The grooves facilitate the removal of the oil film which is formed on the frictional surface, and thereby improves torque transmission and speeds engagement. In addition, the presence of the specially configured grooves causes the coefficient of friction to decrease gradually as relative rotational speed decreases, and avoids a sudden increase in the coefficient of friction as engagement is completed.

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Hokkaido, Japan

Norio Takakura