JP3314672B2 - Surface treatment method for wet friction material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a surface of a wet friction material used in a vehicle, and more particularly, to a surface of a wet friction material in which a steel plate is pressed against the surface of the wet friction material and vibrated for a predetermined time. It relates to a processing method.

[0002]

2. Description of the Related Art Conventionally, a wet clutch has been used as one of mediators for transmitting output from a prime mover such as an automobile, a motorcycle and an agricultural machine. In recent years, in the field of automobiles, the development of automatic transmissions has been advanced, and standards required for each component, such as an increase in transmission capacity and maintenance-free, have become higher. Among these wet friction materials, the lock-up friction material is one of the parts requiring the best friction characteristics.

[0003]

However, the wet friction material is obtained by impregnating and curing a binder resin in a paper material obtained by forming a fiber component, a filler, a friction and wear modifier, and the like. Because it is the main resin impregnated body,
The surface has minute irregularities, and in the initial state at the time of completion of the product, it is difficult to come into contact with the partner material (so-called familiarity).

[0004] Accordingly, such conventional wet friction materials have a problem that it is difficult to obtain good friction characteristics from the beginning. In particular, the lock-up friction material is a part that requires not only durability but also excellent friction characteristics from the beginning, and there is room for improvement in this respect.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a friction material which has a more stable friction coefficient from the beginning than a conventional friction material, and It is an object of the present invention to provide a surface treatment method for a wet friction material which realizes a wet friction material excellent in the speed of familiarity with the material.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the steel plate was pressed against the surface of the wet friction material at a predetermined surface pressure and vibrated for a predetermined time to obtain the above-mentioned problems. Have been solved, and the present invention has been completed.

That is, the surface treatment method for a wet friction material according to the present invention, when the surface treatment is performed on a wet friction material containing a fiber component, a filler, a friction and wear modifier, and a binding resin, is performed. The wet friction material and / or the steel sheet is pressed in a direction substantially perpendicular to the pressing direction for 200 to 300 H in a state where the steel sheet is pressed against the steel sheet at a surface pressure of 0.5 to 10 MPa.
It is characterized by vibrating at a frequency of z for 5 to 40 seconds.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for treating a surface of a wet friction material according to the present invention will be described in detail. This surface treatment method
As described above, the steel plate is pressed against the surface of the plate-like wet friction material, and in this state, the steel plate and / or the wet friction material are pressed in a direction substantially perpendicular to the pressing direction, that is, parallel to the surface of the wet friction material. In this direction, vibration is performed at a predetermined frequency for a predetermined time.

Here, the contact pressure when pressing the steel plate is as follows:
0.5 to 10 MPa. When the surface pressure is less than 0.5 MPa, the surface treatment effect intended by the present invention may not be obtained or the treatment time becomes long, which is not practical. On the other hand, if the surface pressure exceeds 10 MPa, the friction characteristics and durability of the obtained wet friction material may be adversely affected, which is not preferable.

The vibration can be performed by displacing the steel plate or the wet friction material and both of them.
Usually, it is performed by displacing a steel plate. At this time, the frequency is 2
It shall be 00-300 Hz. If the frequency is less than 200 Hz, a surface treatment effect can be obtained, but a long treatment time is required, so that it is not as practical as a low surface pressure.

Further, the vibration time can be appropriately changed according to the material, the surface pressure and the frequency of the wet friction material, but under the conditions of the surface pressure of 0.5 to 10 MPa and the frequency of 200 to 300 Hz described above, The time is 5 to 40 seconds at which the processing effect can be sufficiently exhibited.

Conventionally known materials can be used for the fiber component, the filler, the friction and wear control agent and the binder resin constituting the wet friction material. As the fiber component, linter pulp, wood pulp, acrylic fiber , Organic fibers such as polyamide fibers, glass fibers, carbon fibers,
Inorganic fibers such as metal fibers, as fillers, such as calcium carbonate, diatomaceous earth, friction and wear modifiers, such as graphite, cashew dust, molybdenum disulfide, etc., as binding resins, phenolic resins, epoxy resins, melamine resins, Examples include silicone resins.

[0013]

EXAMPLES The present invention will be described below in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Example 1) Cellulose fiber as a fiber component, aromatic polyamide fiber, diatomaceous earth as a filler, and carbon graphite as a friction modifier contained 40, 20, 30, and 10% by weight, respectively. The paper body was impregnated with 35% by weight of a resole phenol resin and cured to obtain a diameter of 133 mm and a width of 10 mm as shown in FIG.
Was obtained.

[0015] Using a vibration welding machine to this wet friction material,
A square steel plate with a side of 200 mm is pressed at a surface pressure of 5.0 (MP
a) in the direction A of FIG.
This steel plate is vibrated at a frequency of 240 (Hz) in the direction of arrow BB '.
Then, the wet friction material was subjected to a surface treatment by vibrating for 30 seconds to obtain a wet friction material of Example 1. Table 1 shows the surface treatment conditions.

(Example 2) The same operation as in Example 1 was repeated except that the surface pressure was set to 8.0 (MPa) to obtain a wet friction material of this example.

Example 3 The same operation as in Example 1 was repeated except that the frequency was set to 200 (Hz), to obtain a wet friction material of this example.

Example 4 The same operation as in Example 1 was repeated except that the surface pressure was set to 8.0 (MPa) and the processing time was set to 5 seconds, to obtain a wet friction material of this example.

Comparative Example 1 The same operation as in Example 1 was repeated except that the surface pressure was changed to 0.1 (MPa) to obtain a wet friction material of this example.

Comparative Example 2 The same operation as in Example 1 was repeated except that the surface pressure was changed to 15 (MPa) to obtain a wet friction material of this example.

Comparative Example 3 The same operation as in Example 1 was repeated except that the frequency was set to 20 (Hz), to obtain a wet friction material of this example.

Comparative Example 4 The same operation as in Example 4 was repeated except that the treatment time was set to 3 seconds, to obtain a wet friction material of this example.

(Test Evaluation) The wet friction materials obtained in the Examples and Comparative Examples were subjected to a low-speed friction tester (JASO).
M349-95), the initial friction coefficient was measured under the following conditions. Also, μ at 100 rpm (μ10
By comparing 0) with μ (μ50) at 50 rpm, the inclination of the friction diagram was obtained, and the performance was compared. Table 1 also shows the obtained results. As the performance of the friction material, a higher μ value is better, and it is desirable that the μ value be constant or increase as the rotation speed increases (rotation speed−μ).
The slope of the diagram is 0 or positive).

Test conditions Temperature: 40 ° C. Surface pressure: 0.91 MPa

[0025]

[Table 1] As shown in Table 1, in Examples 1 and 2, the surface pressure was changed, but in each case, the friction material became familiar, the μ100 was high, and the gradient of the friction diagram was also a positive gradient. It became. On the other hand, when the surface pressure was too low, it was confirmed that good friction characteristics could not be obtained as in Comparative Example 1. Further, when the surface pressure is too high as in Comparative Example 2, the holes are crushed or the like, so that good friction characteristics cannot be obtained, and in this case, the durability life may be adversely affected.

In Examples 3 and 4, the frequency and the processing time of the surface treatment conditions were changed with respect to Examples 1 and 2, respectively.
Although not as good, the friction material has become more familiar,
0 is high, and the slope of the friction diagram is almost flat,
Expression of the treatment effect was observed. On the other hand, if the frequency is too low and the processing time is too short,
The surface treatment became insufficient, and good friction characteristics could not be obtained as in Comparative Examples 3 and 4, respectively.

[0027]

As described above, according to the present invention, the steel plate is pressed against the surface of the wet friction material at a predetermined surface pressure and vibrated for a predetermined time, so that the friction material is more initial than the conventional friction material. Therefore, it is possible to provide a surface treatment method for a wet-type friction material which realizes a wet-type friction material having a stable friction coefficient and excellent in the speed of adaptation to a counterpart material.

That is, a steel sheet is coated on the surface of a wet friction material containing a fiber component, a filler, a friction and wear modifier, and a binder resin by 0.5 to 0.5 mm.
200-300H while pressing with surface pressure of 10MPa
By performing a surface treatment of vibrating at a frequency of z for 5 to 40 seconds, the surface of the friction material is smoothed and conformed, so that good friction characteristics can be obtained from the beginning in a short time,
In addition, a friction material having stable quality can be obtained. Also,
According to this surface treatment method, it is possible to set processing conditions corresponding to various friction materials by changing the surface properties and vibration stroke of the counterpart steel sheet.

[Brief description of the drawings]

FIG. 1 is a perspective explanatory view showing a surface treatment method for a wet friction material of the present invention.

[Explanation of symbols]

 1 friction material 2 steel plate

Continuation of front page (56) References JP-A-4-78331 (JP, A) JP-A-61-103022 (JP, A) JP-A-58-203010 (JP, A) JP-A-58-136677 (JP) JP-A-6-33960 (JP, A) JP-A-5-16161 (JP, A) JP-A-6-500745 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) F16D 69/02 F16D 69/00 C09K 3/14 520

Claims (1)

(57) [Claims] 1. A surface treatment of a wet friction material containing a fiber component, a filler, a friction and wear modifier and a binder resin, wherein a steel plate is applied to the surface of the wet friction material at a surface pressure of 0.5 to 10 MPa. With the steel plate or wet friction material and both
In the direction perpendicular to the pressing direction, 200 to 300
A method for treating a surface of a wet friction material, wherein the surface of the wet friction material is vibrated at a frequency of 5 to 40 seconds.