JP3054716B2 - Friction engagement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frictional engagement device in which a wet friction material is joined to a metal plate such as a steel plate or an aluminum plate to generate a frictional force.

[0002]

2. Description of the Related Art As shown in FIG. 25, a conventional friction engagement device fits a drive plate 2 fitted to a spline portion 51 of a hub 5 fitted to an input shaft 6, and a spline portion 41 of a retainer 4. The torque is transmitted by the contact of the passive plate 1. In the figure, 3 is a pressure plate, and 7 is a piston.

[0003] In general, a friction engagement device is required to be small and light, to have a small operating shock, and to have a high torque capacity, and the demands are extremely large.

[0004]

However, in the conventional friction engagement device, since a lubricating oil having a low friction coefficient is frequently used to reduce the operation shock, if the size is reduced, the torque capacity is inevitably reduced. Would. Therefore, to increase the operating pressing force and increase the torque capacity, the service life of the wet friction material is shortened, the heat spot is generated on the mating friction surface (passive plate) and thermal deformation, the hydraulic pump is enlarged, and the hydraulic oil And
However, in order to solve these problems relating to the durable life and to solve these problems, it is necessary to consider a safety factor, and it has been difficult to reduce the size of the device itself.

[0005]

According to the present invention, a ceramic thin film is formed on at least one of frictional surfaces of a metal plate by a ceramic thin film synthesis method, and the above-mentioned ceramic material is formed. Thin film,
There is provided a friction engagement device characterized by changing a film thickness distribution. By forming the thickness distribution of the ceramic thin film in various forms on the friction surface of the metal plate, a high dynamic friction coefficient (μd) and a high static friction coefficient (μs) can be obtained, and an ideal torque waveform can be obtained over time. It is possible to maintain the target without any significant change, and it is possible to reduce the size of the device.

Further, even if the ceramic thin film is made of the same material, the characteristics are remarkably different depending on the synthesis method, so it is necessary to select a synthesis method that meets the required characteristics. As a method of designing the friction characteristics, by changing the thickness distribution of the ceramic thin film described above, it is possible to produce a product having the intended friction characteristics, and thus the above-mentioned problem can be solved.

[0007]

[Operation] A ceramic thin film (for example, TiC, TiN, SiC, or the like) is formed on both sides or one side of a metal plate such as a steel plate or an aluminum plate forming the passive plate 1 of the friction engagement device shown in FIG.
Si ₃ N ₄ , BN, Al ₂ O ₃ , TaN, CrN, Ti
CN and i carbon films (amorphous transparent hard carbon films) and the like. ) Surface treatment. Examples of the surface treatment method include a gas phase method, a melt method, a solution salt method, and a solution method as a method of synthesizing a ceramic thin film on a base material surface as a thin film synthesis method.

The surface roughness of the passive plate after treatment is the same as that of the underlying surface when the surface is treated with small particles. Therefore, the surface roughness after the treatment can be adjusted by processing the treated surface or Must be set before processing.

Conventionally, the passive plate plays a role of transmitting torque or transmitting heat from the driving surface. However, by performing various surface treatments as described above, the passive plate has a frictional characteristic as shown in FIGS. An improvement can be obtained. (Detailed description will be given later.)

[0010]

FIG. 1 is a perspective view showing the relationship between a passive plate 1 and a driving plate 2.
FIG. 2 is a side sectional view. The passive plate 1 is made of a metal plate 9 such as a steel plate or an aluminum plate, and has spline teeth 91.

The drive plate 2 has a wet friction material 8 on both sides of a metal plate 9.
Is affixed. In the present invention, the central passive plate 1 is subjected to ceramics treatment on both sides, and the passive plates 1 ', 1' at both ends are subjected to ceramics surface treatment on only one surface.

FIG. 3 is an enlarged view of the vicinity of the spline teeth 91 of the passive plate 1, and FIGS. 4 and 5 are sectional views taken along line XX of FIG. FIG. 4 shows a case where the ceramic thin film 10 is provided on the entire surface of the metal plate 9, and FIG. 5 shows a case where the thin film exists on only one surface.

In FIGS. 4 and 5, the thickness of the thin film 10 is exaggerated relative to the size of the metal plate 9 for easy understanding. FIG. 6 is a perspective view of another embodiment, and FIG. 7 is a side sectional view when they are in contact with each other. Both the passive plate 1 and the driving plate 2 have a wet friction material 8 adhered to only one surface, and the opposite. A metal plate appears on the surface, and a ceramic surface treatment is applied.

FIGS. 8 to 11 show the form of the surface treatment of the embodiment shown in FIG. 6, FIG. 8 shows the surface of the passive plate 1 on the ceramics treatment side, FIG. Shows the surface of the drive plate 2 on the ceramics processing side, and FIG. 11 is a sectional view taken along the line YY. In each of the figures, 8 indicates a wet friction material, 10 indicates a ceramic thin film, and black dots indicate a thin film distribution. The film thickness of the thin film 10 is changed so that the inner peripheral side increases in thickness.

FIGS. 12 to 24 show various modifications of the ceramic surface treatment, and FIGS. 12, 14, 16, 19, 21 and 23 show the surface on the ceramic surface treatment side. The following figure shows a sectional view taken along line XX. 12 and 13 are modifications of FIG. 8, and FIG.
FIG. 15 shows an example in which the thickness of the thin film changes stepwise,
FIGS. 16, 17, and 18 show examples in which the ceramic surface treatment is partially performed. FIG.
Corresponds to the plate at the end.

FIGS. 19 and 20 show an example in which the surface treatment is not partially performed, and the portion can be formed into an oil groove 11 in the circumferential direction. In this example, by increasing the width of the unprocessed portion toward the outer peripheral portion, the strain distribution in the inner peripheral portion can be averaged, and the cooling performance can be improved. FIG. 21, FIG.
19 is a modification of FIG. 19, in which the unprocessed portion is a closed shape 12, and the shape, the number, the size, the position, and the like are determined according to the use condition from the cooling effect and the balance of the inner and outer processing areas. I do.

FIGS. 23 and 24 show the case where the unprocessed portion is a groove 14 in the radial direction. In consideration of the use conditions, the angle, number, penetration, Determine non-penetration, etc. In addition, various modes other than the examples given variously after FIG. 8 are possible.

FIGS. 26 to 29 show the characteristics of the frictional force (torque) according to the change in the sliding speed in the durability test. 26 shows the characteristics of the device of the present invention in the early stage of durability, FIG. 27 shows the characteristics of the conventional device in the early stage of durability, FIG. 28 shows the characteristics of the device of the present invention, and FIG. 29 shows the characteristics of the conventional device after durability.

In each of the figures, the vertical axis shows the clutch torque (frictional force), the horizontal axis shows the braking time (the time required to stop the rotated flywheel, A is the invention, B is Indicates a change of the conventional one, and in the conventional one, a peak called a rooster tail occurs immediately before the rotation speed becomes 0, and the μ-V characteristic (the characteristic indicating the change of the friction coefficient μ with the change of the sliding speed) is also obtained. In addition, the upper right characteristic which is disadvantageous to the operation shock is shown.

In the present invention, using the same wet friction material and the same lubricating oil, the rooster tail disappears, the μ-V characteristic also shows a tendency to flatten or go down to the right, and the absolute value of the torque (dynamic friction coefficient μd, static friction coefficient μs) is reduced. The level is 20-40%
The results have improved. This is not only very advantageous for operating shock, but also makes it possible to obtain a high torque capacity while suppressing the occurrence of self-excited vibration such as judder when used for continuous sliding.

FIGS. 30 and 31 show the change over time in the coefficient of friction (dynamic / static) of the device of the present invention and the conventional product during the durability test.
FIG. 30 shows the dynamic friction coefficient, and FIG. 31 shows the static friction coefficient. In each figure, A shows the change of the present invention and B shows the change of the conventional product. A is stable, and is flat regardless of the number of cycles (the number of tests). On the other hand, the conventional product shows a large change with time.

[0022]

The friction engagement device according to the present invention has the above-described configuration, and (1) improves the dynamic friction coefficient and the static friction coefficient;
(2) Elimination of peak generation by improving friction characteristics, and (3) Improvement of friction coefficient over time during long-term use, resulting in a smaller, lighter, and higher torque capacity of the friction engagement device, thereby improving reliability. The effect is that a product with high quality can be provided.

The friction engagement device of the present invention is used not only for the multi-plate clutch shown in the embodiment, but also for various applications such as a direct coupling clutch of a torque converter, a brake band, and a synchronizer ring of a transmission.

[Brief description of the drawings]

FIG. 1 shows an arrangement of a passive plate and a driving plate.

FIG. 2 is a side sectional view

FIG. 3 is a partially enlarged view

4 and 5 are cross-sectional views taken along line XX of FIG.

FIG. 6 shows an arrangement of another embodiment.

FIG. 7 is a side sectional view;

FIG. 8 is a front view of one embodiment.

9 is a sectional view taken along line XX of FIG.

FIG. 10 is a front view of another embodiment.

11 is a sectional view taken along line XX of FIG.

FIG. 12 is a front view of another embodiment.

FIG. 13 is a sectional view taken along line XX of FIG. 12;

FIG. 14 is a front view of another embodiment.

FIG. 15 is a sectional view taken along line XX of FIG. 14;

FIG. 16 is a front view of another embodiment.

17 and 18 are XX cross-sectional views of FIG.

FIG. 19 is a front view of another embodiment.

20 is a sectional view taken along line XX of FIG. 19;

FIG. 21 is a front view of another embodiment.

FIG. 22 is a sectional view taken along line XX of FIG. 21;

FIG. 23 is a front view of another embodiment.

24 is a sectional view taken along line XX of FIG.

FIG. 25 is a side sectional view of an example of the friction engagement device.

FIG. 26 is a diagram showing a relationship between clutch torque and braking time in the initial stage of durability according to the present invention.

FIG. 27 is a diagram similar to FIG. 26 of a conventional device.

FIG. 28 is a view similar to FIG. 26 after durability of the thing of the present invention.

FIG. 29 is a view similar to FIG. 26 after the endurance of the conventional one.

FIG. 30 is a diagram showing a change with time of a dynamic friction coefficient.

FIG. 31 is a diagram showing a change over time in a coefficient of static friction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Passive plate 2 Drive plate 3 Pressure plate 4 Retainer 41 Spline part 5 Hub 51 Spline part 6 Input shaft 7 Piston 10 Ceramic thin film 11 Groove 12 Closed groove or hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-249628 (JP, A) JP-A-2-278022 (JP, A) JP-B-46-15043 (JP, B1) (58) Field (Int.Cl. ⁷ , DB name) F16D 13/62 C23C 30/00 F16D 69/00

Claims (5)

(57) [Claims] 1. A friction engagement device in which a wet friction material is joined to a metal plate such as a steel plate or an aluminum plate to generate a frictional force, wherein at least one of the friction surfaces of the metal plate is formed by a ceramic thin film synthesis method. Rutotomoni to form a ceramic film,
A friction engagement device characterized in that the thickness distribution of the ceramic thin film is changed . 2. Gold subjected to the above-mentioned ceramic surface treatment
In metal plates, the roughness of the metal plate or ceramics
Claims characterized by changing the surface roughness distribution of the thin film
Item 3. The friction engagement device according to Item 1 . 3. The size of the ceramic particles on the same surface of the metal plate subjected to the above-mentioned ceramic surface treatment.
Characterized in that varying according to claim 1 or 2
The friction engagement device according to claim 1. 4. In the metal plate which has been subjected to the ceramic surface treatment, two or more types of ceramics are used as a thin film.
The frictional engagement device of any one of claims 1 to 3, characterized in that to form. 5. In the metal plate subjected to the ceramic surface treatment, the ceramic surface treatment is partially performed.
The method according to any one of claims 1 to 4, wherein
Item 8. The friction engagement device according to Item 1.