KR20170064459A - Brake pad for vehicle - Google Patents

Abstract

According to an embodiment of the present invention, a vehicle brake pad is contacted with a brake disk to generate a braking force, the brake pad comprising: a back plate layer; A lower layer disposed over the entire back plate layer; An adhesive layer mediating the back plate layer and the lower layer material layer; And a friction material layer joined to the front surface of the lower layer and contacting the brake disc to generate a frictional force, wherein a shim for attenuating noise is omitted, and a noise of 200 to 20,000 Hz in a temperature range of -100 to 300 ° C At least one of the back plate layer, the adhesive layer and the lower layer layer has a loss factor calculated by the following formula (1) in a temperature range of -100 to 300 캜 of not less than 0.2 .
Loss coefficient (?) = (F ₂ -f ₁ ) / f ₀ (1)
(Where η is the loss factor, f _{0 is the} noise generation frequency, f ₁ is the lower limit of the amplitude at the 3 dB attenuation of the noise generation frequency, and f ₂ is the upper limit of the amplitude at the 3 dB attenuation of the noise generation frequency).

Description

BRAKE PAD FOR VEHICLE

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pad, and more particularly, to a brake pad for a vehicle, which extends a damping noise and temperature range and is excellent in durability without a separate shim.

Generally, a brake applied to a vehicle plays a most important role in safe driving. It is divided into a disc brake and a drum brake according to a method of generating a frictional force. In recent years, The disc brake is less susceptible to a reduction in braking force.

The disc brake is designed to strongly press the brake pad operated by hydraulic pressure from one side or both sides of a disc-shaped brake disc rotating together with the wheel instead of the drum to obtain the braking force by the frictional force generated at this time.

1 is a cross-sectional view showing a conventional brake pad.

As shown in FIG. 1, the brake pad is composed of a frictional material 10, which is a portion that actually carries actual friction, and a backplate layer 40, which transmits pressure from the hydraulic cylinder.

The back layer 40 is disposed between the back plate layer 40 and the friction material layer 10 to block the heat transmitted to the caliper and improve the feeling of movement. (20).

The lower layer layer 20 has a purpose of reducing the cost by using a raw material less expensive than the friction material layer 10 for the above purposes.

In addition, a wear sensor (not shown) that measures the amount of wear of the friction material layer 10 to prevent wear due to direct friction between the backplate layer 40 and the disk when the friction material layer 10 is worn beyond the limit Wear Indicator 50 may be adhered to the back plate layer 40.

Further, in order to improve the conventional NVH characteristics, a shim 60 is attached to a portion where the backplate layer 40 contacts the caliper hydraulic piston during braking. This restrains the heat generated during braking from being transmitted to the cylinder and also acts as a damper to the noise generated by the vibration.

The padding 60 is manufactured by using a rubber or a steel material having vibration damping properties and then bonded to the back surface of the backplate layer 40. The thickness of the padding 60 is limited to 1 to 2 mm In addition, since the material is also limited to rubber and some steel materials, it is possible to improve the vibration damping property in a specific temperature range in which the vibration damping property is narrow, and when the vibration damping property is out of the temperature range, I had a problem.

Korean Patent No. 10-0824911 (Apr. 17, 2008)

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a brake pad for a vehicle that can attain a satisfactory attenuation capability while expanding a temperature range at which noise can be attenuated.

Further, the present invention provides a brake pad for a vehicle that improves the braking accuracy and stability while improving the durability by improving the coupling force between the back plate and the friction material.

According to an embodiment of the present invention, a vehicle brake pad is a brake pad for generating a braking force in contact with a brake disc, the brake pad comprising: a back plate layer; A lower layer disposed over the entire back plate layer; An adhesive layer mediating the back plate layer and the lower layer material layer; And a friction material layer joined to the front surface of the lower layer and contacting the brake disc to generate a frictional force, wherein a shim for attenuating noise is omitted, and a noise of 200 to 20,000 Hz in a temperature range of -100 to 300 ° C At least one of the back plate layer, the adhesive layer and the lower layer layer has a loss factor calculated by the following formula (1) in a temperature range of -100 to 300 캜 of not less than 0.2 .

Loss coefficient (?) = (F ₂ -f ₁ ) / f ₀ (1)

(Where η is the loss factor, f _{0 is the} noise generation frequency, f ₁ is the lower limit of the amplitude at the 3 dB attenuation of the noise generation frequency, and f ₂ is the upper limit of the amplitude at the 3 dB attenuation of the noise generation frequency).

The backplate layer may be formed of an Fe-Mn based anti-vibration alloy containing 15 to 25 wt% of manganese (Mn).

The backplate layer preferably has a loss coefficient of 0.2 or more at 25 to 300 ° C.

The adhesive layer may be an acrylic vibration damping adhesive having a loss coefficient of 0.2 or more at 0 to 100 ° C.

The underlayer layer comprises 10 to 20 wt% of a binder, 20 to 30 wt% of a filler, 5 to 20 wt% of a reinforcement, 15 to 40 wt% of an elastomer, 10 to 30 wt% of an inorganic control material, Wherein the elastomer comprises at least one of NBR, EPDM and SBR rubbers, and the reinforcing material preferably contains aramid-based organic fibers.

The lower layer layer may have a loss coefficient of 0.2 or more at a temperature of -100 to 50 캜.

In the brake pads for a vehicle according to an embodiment of the present invention, the back plate layer and the friction layer are formed with uneven surfaces that engage with each other on an opposite surface, and the lower layer layer and the adhesive layer are bent along the uneven surface .

According to the embodiment of the present invention, the back plate layer, the lower layer material layer, and the adhesive layer are formed so that a loss coefficient of at least one layer is 0.2 or more in a temperature range of -100 to 300 캜 to extend the temperature range in which noise can be attenuated There is an effect that the attenuation effect can be improved.

In addition, since a separate shim for noise reduction is not needed, it is possible to reduce the production cost and simplify the structure of the brake pad.

Further, by forming the uneven surface on the opposite surfaces of the back plate layer and the friction material layer, it is possible to improve the bonding force between the back plate layer and the friction material layer and improve the braking accuracy and stability by improving the shear strength of the brake pad .

1 is a cross-sectional view showing a conventional brake pad,
Fig. 2 is a diagram for explaining a method of calculating the loss coefficient?
3 is a sectional view showing a brake pad for a vehicle according to an embodiment of the present invention,
FIG. 4 is a graph showing attenuation coefficients according to temperature for conventional brake pads and brake pads for a vehicle according to an embodiment of the present invention,
5 is a graph showing the attenuating ability of the material of the back plate layer according to temperature,
6 is a graph showing the attenuating ability of the backplate layer according to manganese (Mn) content,
7 is a graph showing a loss coefficient according to temperature of an adhesive layer according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments.

For reference, the same numbers in this description refer to substantially the same elements and can be described with reference to the contents described in the other drawings under these rules, and the contents which are judged to be obvious to the person skilled in the art or repeated can be omitted.

In the present invention, in order to attenuate noise having an audible frequency of 20 to 20,000 Hz in a temperature range of 100 to 300 DEG C while omitting a shim in a multi-layered vehicle brake pad, Damping Capacity) is improved to simplify the structure while expanding the temperature range for attenuating the noise of the audible frequency.

At this time, the attenuation ability of the brake pad can be expressed by a loss coefficient.

Fig. 2 is a diagram for explaining a method of calculating the loss coefficient?.

2, the loss factor (η) is a noise frequency at the time the output from the noise frequency (f ₀₎ and the noise frequency (f ₀₎ that cause the generation of noise is 3dB attenuation (f ₀₎ Can be calculated according to the following equation (1) using the lower limit value f ₁ and the upper limit value f ₂ of the amplitude.

Loss coefficient (?) = (F ₂ - f ₁ ) / f ₀ ---------------------------------- ---- (One)

(Where η is the loss factor, f _{0 is the} noise generation frequency, f ₁ is the lower limit of the amplitude at the 3 dB attenuation of the noise generation frequency, and f ₂ is the upper limit of the amplitude at the 3 dB attenuation of the noise generation frequency).

Further, the loss coefficient? Calculated as above can be converted into the attenuation ratio? By the following equation (2).

Attenuation ratio (?) = Loss coefficient (?) / 2 ----------------------------- (2)

FIG. 3 is a cross-sectional view showing a brake pad for a vehicle according to an embodiment of the present invention, FIG. 4 is a graph showing attenuation coefficients according to temperature for a conventional brake pad and a vehicle brake pad according to an embodiment of the present invention .

3, a vehicle brake pad according to an embodiment of the present invention includes a back plate layer 100 for releasing heat generated during braking while transmitting pressure of a hydraulic cylinder, A lower layer 300 for preventing transmission of heat and vibration generated during braking and a bonding layer 200 for mediating between the backplate layer 100 and the lower layer 300 and a lower layer 300, And a friction material layer 400 which is in direct contact with the disc to generate frictional force.

The brake pad for a vehicle according to an embodiment of the present invention includes a back plate layer 100, an adhesive layer 200, and a lower layer layer (not shown) so as to attenuate a noise frequency of 200 to 20,000 Hz in a temperature range of -100 to 300 ° C. 300) preferably has a loss coefficient (?) Calculated by the above formula (1) at a temperature range of -100 to 300 占 폚 of 0.2 or more.

As shown in FIG. 4, the conventional brake pad has a loss coefficient (η) of 0.2 or more in a temperature range of about 25 to 200 ° C., whereas the brake pad for a vehicle according to an embodiment of the present invention has a conventional brake pad It is found that the loss coefficient (?) Is 0.2 or more in a temperature range of -100 to 300 占 폚 which is wider, and the noise attenuating ability can be improved over a wide temperature range as compared with the conventional case.

The backplate layer 100 may include a gray iron or a dislocation in which precipitates such as graphite are developed in order to obtain the vibration damping performance of the metal, so that the external vibration can be effectively attenuated due to internal energy exhaustion And a steel plate for pressing having vibration damping properties. The back plate layer according to an embodiment of the present invention is preferably manufactured using an Fe-Mn type vibration damping alloy containing 15 to 25 wt% of manganese (Mn) Do.

5 is a graph showing the attenuating ability of the material of the back plate layer according to the temperature.

As shown in FIG. 5, the composite sandwich steel of the pressing steel sheet which can be used as a conventional backplate layer has a temperature range of about -10 to 50 ° C. in which the attenuation capacity is about 32% In addition, it shows that the attenuating ability decreases sharply toward the high temperature, and the carbon black steel has a low attenuating ability, so that the noise attenuating effect is low.

On the other hand, Fe-Mn based alloys containing 17 wt% of manganese (Mn) have excellent attenuation capability over 32% in a wide temperature range. It is possible to secure an excellent attenuating ability in a temperature range.

6 is a graph showing the attenuating ability of the backplate layer according to manganese (Mn) content.

As shown in FIG. 6, when the content of manganese (Mn) in the backplate layer 100 according to an embodiment of the present invention is 15 to 25 wt%, excellent attenuating ability of 20% or more can be secured, When the manganese (Mn) content is out of the above range, the attenuation capacity is lowered to less than 20%, and the noise damping ability is deteriorated.

Therefore, the backplate layer according to an embodiment of the present invention preferably has a content of manganese (Mn) of 15 to 25 wt%.

As described above, the brake pad for a vehicle according to an embodiment of the present invention includes a back plate layer 100 made of Fe-Mn based alloy having a Mn content of 15 to 25 wt% By securing the loss coefficient to 0.2 or more in the temperature range, it is possible to improve the noise attenuation ability in the temperature range.

The lower layer 300 according to an embodiment of the present invention is formed of a polymer material including an oxide-based inorganic material having an adiabatic property and an elastomer. Preferably, the lower layer 300 has a loss coefficient of 0.2 or more at a temperature of -100 to 50 ° C Do.

According to an embodiment of the present invention, the lower layer comprises at least one member selected from the group consisting of 10 to 20 wt% of a binder, 20 to 30 wt% of a filler, 5 to 20 wt% of a reinforcement, 15 to 40 wt% of an elastomer, 10 to 30 wt% and inevitable impurities.

Component Material
(wt%) Phenolic Resin Filler
(Barite + calcium hydroxide) Reinforced material (aramid fiber + copper fiber) Elastomer Inorganic conditioning material (Cashew powder) Comparative Example 20 45 10 10 15 Example 1 19 15 18 29 19 Example 2 19 15 18 30 18 Example 3 19 15 18 28 20

Table 1 is a table showing the composition of a conventional lower layer and a lower layer 300 according to an embodiment of the present invention.

As shown in Table 1, it is preferable that the lower layer 300 according to an embodiment of the present invention includes 15 to 40 wt% of an elastomer so that the retardation can be improved in a temperature range of -100 to 50 캜 .

This is because when the elastomer content is less than 15 wt%, the effect of noise attenuation is insignificant in the temperature range of -100 to 50 캜, and when the elastic polymer content is more than 40 wt%, the properties such as compressive strain / density / hardness of the lower layer 300 It is not possible to satisfy the required physical property value.

At this time, the elastomer may include at least one of NBR, EPDM, and SBR rubbers. The reinforcing material may be an aramid-based organic fiber, more preferably a material having excellent bonding strength with the friction material layer 400 Can be used.

The lower layer layer 300 according to an embodiment of the present invention is formed by injecting a material prepared as described above into a friction material layer 400 formed in a mold and pressurizing the material at a temperature of 150 to 180 ° C at 500 to 700 kgf / .

Meanwhile, the adhesive layer 200 according to an embodiment of the present invention can be formed by applying a high elastic acrylic vibration damping adhesive having a loss coefficient of 0.2 or more in a temperature range of 0 to 100 ° C by applying or spraying.

7 is a graph showing a loss coefficient according to temperature of an adhesive layer according to an embodiment of the present invention.

As can be seen from FIG. 7, the adhesive layer 200 manufactured according to the embodiment of the present invention exhibits excellent vibration damping properties with a loss coefficient of 0.2 or more in a temperature range of 0 to 100 ° C.

Meanwhile, it is preferable that the friction material layer 400 and the backplate layer 100 according to an embodiment of the present invention have irregular surfaces that are engaged with each other.

This is because the backplate layer 100 according to one embodiment of the present invention has a high surface hardness, and therefore, it is difficult to perform the surface treatment for improving the shearing force with the adhesive layer 200.

Accordingly, the bonding force between the friction material layer 400 and the back plate layer 100 is improved to improve the braking accuracy and stability by improving the shear strength of the brake pads manufactured according to the embodiment of the present invention.

As described above, according to the embodiment of the present invention, the adhesive layer 200 has a loss factor of 0.2 or more in a temperature range of 0 to 100 캜, and a loss factor of 0.2 or more at a temperature of 25 to 300 캜. Coefficient is 0.2 or more, and the lower layer layer 300 has a loss coefficient of 0.2 or more in a temperature range of -100 to 50 占 폚.

Therefore, the brake pad for a vehicle according to one embodiment of the present invention, including the backplate layer 100, the lower layer 300, and the adhesive layer 200, The noise attenuation characteristic can be improved.

division 1st 2nd Total Ave. Comparative Example 0 ℃ Freq. (KHz) 2.696 8.744 1.891 Damping ratio (%) 0.600 0.755 25 ℃ Freq. (KHz) 2.656 8.604 1.826 Damping ratio (%) 0.574 0.978 100 ℃ Freq. (KHz) 2.480 8.488 2.100 Damping ratio (%) 0.597 0.838 Example 0 ℃ Freq. (KHz) 2.524 8.220 2.080 Damping ratio (%) 0.800 1.287 25 ℃ Freq. (KHz) 1.932 8.120 3.043 Damping ratio (%) 3.984 1.550 100 ℃ Freq. (KHz) 1.832 8.112 3.009 Damping ratio (%) 2.419 1.176

Table 2 is a table showing the natural frequency and attenuation ratio according to the temperature of the embodiments of the present invention and the comparative examples.

As shown in Table 2, the brake pad for a vehicle manufactured according to an embodiment of the present invention not only improves the noise attenuation characteristic over a wide range as compared with the conventional brake pad, but also has a frequency range of natural frequency (FRF) The attenuation ability at room temperature was maintained at 20% or more while the fluctuation was maintained within 3%. It can be seen that the attenuation ratio according to the temperature is improved compared to the conventional brake pad.

Accordingly, the brake pad for a vehicle according to an embodiment of the present invention can attenuate a noise range of 200 to 20,000 Hz in a temperature range of -100 to 300 ° C. and can improve a damping capability, .

Although the present invention has been described with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the following claims. It can be understood that

100: back plate layer 200: adhesive layer
300: lower layer layer 400: friction layer

Claims (7)

1. A brake pad for a vehicle which is brought into contact with a brake disk to generate a braking force,
A backplate layer;
A lower layer disposed over the entire back plate layer;
An adhesive layer mediating the back plate layer and the lower layer material layer; And
And a friction material layer joined to the entire surface of the lower layer layer and contacting the brake disc to generate frictional force,
At least one of the back plate layer, the adhesive layer and the lower layer layer is formed at a temperature of -100 to 300 ° C so as to attenuate a noise of 200 to 20,000 Hz in a temperature range of -100 to 300 ° C, Wherein a loss factor calculated by the following formula (1) is 0.2 or more in a temperature range of?
Loss coefficient (?) = (F ₂ -f ₁ ) / f ₀ (1)
(Where η is the loss factor, f _{0 is the} noise generation frequency, f ₁ is the lower limit of the amplitude at the 3 dB attenuation of the noise generation frequency, and f ₂ is the upper limit of the amplitude at the 3 dB attenuation of the noise generation frequency).
The method according to claim 1,
Wherein the backplate layer comprises:
Wherein the brake pad is made of an Fe-Mn-based vibration damping alloy containing 15 to 25 wt% of manganese (Mn).
The method of claim 2,
Wherein the backplate layer comprises:
And a loss coefficient of 0.2 or more at 25 to 300 占 폚.
The method according to claim 1,
The adhesive layer
And the acrylic vibration damping adhesive has a loss coefficient of 0.2 or more at 0 to 100 占 폚.
The method according to claim 1,
The underlayer
Wherein the reinforcing material is composed of 10 to 20 wt% of a binder, 20 to 30 wt% of a filler, 5 to 20 wt% of a reinforcing material, 15 to 40 wt% of an elastomer, 10 to 30 wt% of an inorganic controlling material, Wherein the polymer comprises at least one of NBR, EPDM and SBR rubbers, wherein the reinforcement contains aramid based organic fibers.
The method of claim 5,
The underlayer
And a loss coefficient of 0.2 or more at a temperature of -100 to 50 占 폚.
The method according to claim 1,
Wherein the back plate layer and the friction layer are formed with concave and convex surfaces engaging with each other on opposite surfaces thereof, and the lower layer layer and the adhesive layer are folded along the uneven surface.

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