Friction material and friction block for brake shoe of washing machine and preparation method of friction material and friction block

Abstract

The invention provides a friction material and a friction block for a washing machine brake shoe and a preparation method thereof, and relates to the technical field of washing machines. The friction material for the brake shoe of the washing machine comprises the following components in percentage by volume: 8%-18% of organic silicon resin, 12%-18% of powdered styrene-butadiene rubber, 15%-25% of mineral fibers, 18%-28% of a graphite lubricant, 10%-20% of calcium silicate and 10%-15% of aluminum oxide. The friction material for the washing machine brake shoe has the advantages that braking is stable and mute, the service life is long, the service life of a braking pair can be prolonged, and the friction material is suitable for the washing machine brake shoe; furthermore, water-based organic silicon resin is adopted in the friction material, emission of volatile organic compounds is greatly reduced, and the environmental protection property of the friction material is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of washing machines, and in particular to a friction material and a friction block for a washing machine brake shoe and a preparation method thereof. Background Art

[0002] In the development of washing machines, intelligence, high efficiency, energy saving, and environmental protection and health have gradually become important development directions to continuously meet the increasingly diverse and refined needs of consumers. As a key safety component in washing machines, washing machine brake shoes play a vital role. During the spin cycle, washing machine brake shoes effectively control the washing machine's rotation speed, avoiding severe vibration caused by clothing misalignment, ensuring stable operation of the machine and the personal and property safety of users. If potential hazards such as abnormal vibration are detected, the brake shoes can automatically cut off the power supply and stop the washing machine, effectively preventing machine damage and various safety accidents.

[0003] Therefore, the requirements for friction materials used in brake shoes primarily include an appropriate and stable coefficient of friction, good wear resistance, excellent mechanical strength and physical properties, low braking noise, and minimal wear on the braking mating surface. These requirements ensure the safety and durability of the washing machine during operation, while also taking into account environmental considerations and user experience. Summary of the Invention

[0004] In view of the above problems existing in the prior art, the present invention provides a friction material and a friction block for a washing machine brake shoe and a preparation method thereof, so as to meet the use requirements of the washing machine brake shoe.

[0005] To achieve the above-mentioned and other related purposes, the first aspect of the present invention provides a friction material for a washing machine brake shoe. Calculated by volume percentage of the friction material, the friction material comprises the following components: 8% to 18% silicone resin, 12% to 18% powdered styrene-butadiene rubber, 15% to 25% mineral fiber, 18% to 28% graphite lubricant, 10% to 20% calcium silicate, and 10% to 15% aluminum oxide.

[0006] In one embodiment of the present invention, the friction material includes the following components, measured by volume percentage: 10% to 16% silicone resin, 14% to 16% powdered styrene-butadiene rubber, 18% to 22% mineral fiber, 20% to 26% graphite lubricant, 12% to 18% calcium silicate, and 11% to 14% aluminum oxide.

[0007] In one embodiment of the present invention, the friction material includes the following components, measured by volume percentage: 13% silicone resin, 15% powdered styrene-butadiene rubber, 20% mineral fiber, 24% graphite lubricant, 15% calcium silicate, and 13% aluminum oxide.

[0008] In one embodiment of the present invention, the graphite lubricant includes graphite powder, flake graphite and granular graphite, and the mass ratio of the graphite powder, the flake graphite and the granular graphite is 1:(1-1.5):(1-1.5).

[0009] In one embodiment of the present invention, the particle size of the graphite powder is 50-80 μm, and the particle size of the granular graphite is 150-550 μm.

[0010] In one embodiment of the present invention, the organic silicone resin is a water-based organic silicone resin, and the gel time of the water-based organic silicone resin at 150° C. is 120 seconds.

[0011] In one embodiment of the present invention, the mineral fiber includes any one of wollastonite fiber, mineral rock wool, and aluminum silicate fiber.

[0012] In one embodiment of the present invention, the particle size of the calcium silicate is 3-50 μm.

[0013] In one embodiment of the present invention, the particle size of the calcium silicate is 6-11 μm.

[0014] A second aspect of the present invention provides a friction block for a washing machine brake shoe, wherein the friction block is made of the above-mentioned friction material.

[0015] A third aspect of the present invention provides a method for preparing a friction block for a washing machine brake shoe, comprising the following steps:

[0016] Mixing of friction material raw materials: Take the friction material in proportion and place it in a blender and mix it evenly;

[0017] Hot pressing molding: put the evenly mixed friction material into a hot press and press it into shape to obtain a semi-finished friction block;

[0018] Grinding: Grinding the hot-pressed friction block semi-finished product to a desired thickness and curvature to obtain a friction block.

[0019] In one embodiment of the present invention, the blade speed of the mixer is 2000-3000 r / min, and the stirring time is 10-15 min.

[0020] In one embodiment of the present invention, the pressing pressure of the hot pressing molding is 3-5 MPa, the hot pressing temperature is 130-160° C., and the hot pressing time is 2-10 min.

[0021] The friction material for the brake shoe of the washing machine of the present invention is a combination of rubber and silicone resin as a binder to form a material matrix, which can improve the elasticity of the friction material. The combination of rubber and calcium silicate can increase the porosity of the friction material and reduce the braking noise of the friction material. Furthermore, the silicone resin in the friction material adopts a water-based silicone resin, which can greatly reduce the emission of volatile organic compounds and improve the environmental friendliness of the friction material. The friction block made using the friction material of the present application has smooth and silent braking, a long service life, and can extend the service life of the braking pair, and is suitable for the brake shoe of a washing machine. In addition, the method for preparing the friction block of the present invention is simple in process, highly operable, low in equipment cost, high in production efficiency, and the friction block has a low wear rate and high shear resistance, which ensures the safety and durability of the washing machine during operation, while also improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 The present invention is a flow chart of the preparation of a friction material for a washing machine brake shoe in one embodiment. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following examples and the features in the examples can be combined with each other unless they conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific embodiments, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0025] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those in the examples of the present invention may also be used to implement the present invention.

[0026] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0027] The present invention provides a friction material for a washing machine brake shoe. The friction material comprises the following components, calculated by volume percentage: 8% to 18% of a water-based organic silicone resin, 12% to 18% of powdered styrene-butadiene rubber, 15% to 25% of mineral fiber, 18% to 28% of a graphite lubricant, 10% to 20% of calcium silicate, and 10% to 15% of aluminum oxide.

[0028] In one embodiment, the friction material includes the following components, measured by volume percentage: 10% to 16% silicone resin, 14% to 16% powdered styrene-butadiene rubber, 18% to 22% mineral fiber, 20% to 26% graphite lubricant, 12% to 18% calcium silicate, and 11% to 14% aluminum oxide.

[0029] In one embodiment, the friction material includes the following components, measured by volume percentage: 13% organic silicone resin, 15% powdered styrene-butadiene rubber, 20% mineral fiber, 24% graphite lubricant, 15% calcium silicate, and 13% aluminum oxide.

[0030] In one embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite. Graphite powder helps reduce pair wear, but an excessive amount can make brake shoe molding difficult. Graphite flake helps reduce brake noise, but an excessive amount can increase brake shoe wear. Graphite granules help extend service life, but an excessive amount can reduce brake shoe strength. In this application, the mass ratio of graphite powder, flake graphite, and granular graphite is 1:(1-1.5):(1-1.5), for example, any value of 1:(1-1.5):(1-1.5), such as 1:1:1, 1:1.2:1.5, or 1:1.5:1.3.

[0031] In one embodiment, the particle size of the graphite powder is 50-80 μm, and the particle size of the granular graphite is 150-550 μm.

[0032] As a bonding material, the silicone resin firmly binds the metal particles, fibers, and other fillers to form a uniform friction layer while withstanding repeated thermal stress. In one embodiment, the silicone resin is a water-based silicone resin, and the gel time of the water-based silicone resin at 150°C is 120 seconds. Water-based silicone resin is a silicone polymer material with water as a dispersion medium or solvent. A stable emulsion or solution is formed by modifying the silicone polymer and dispersing it in water. Its molecular backbone is composed of silicon-oxygen bonds (Si-O), and the side chains are connected to organic groups. Water-based technology can significantly reduce the volatile organic compound (VOC) content of silicone resin.

[0033] In one embodiment, the mineral fiber comprises any one of wollastonite fiber, mineral rock wool, and aluminum silicate fiber. In other embodiments, the mineral fiber may also be other mineral fibers commonly used in the art, as long as they meet the use requirements and do not harm human health.

[0034] In this application, calcium silicate is a honeycomb-shaped porous material that increases porosity within the friction material, improving the mixing effect of the friction material. Furthermore, the microstructure of calcium silicate has energy-absorbing properties, absorbing friction vibration energy and reducing vibration amplitude. In some embodiments, the calcium silicate has a particle size of 3 to 50 μm, and in other embodiments, the calcium silicate has a particle size of 6 to 11 μm. For example, the pores of the calcium silicate are on the micron scale.

[0035] The friction material for washing machine brake shoes of the present invention has a moderate and stable friction coefficient, good wear resistance, good mechanical strength and physical properties, low braking noise, is suitable for washing machine brake shoes, and has less wear on the mating surfaces; furthermore, no metal fibers are added to the friction material, no damage is done to the braking mating pairs, no braking sparks are generated, and no prohibited substances such as asbestos, lead and its compounds, hexavalent chromium, etc. are added, which can reduce damage to the human body and is an environmentally friendly friction material.

[0036] The present invention provides a friction block for a washing machine brake shoe, which is made of the above-mentioned friction material.

[0037] The present invention provides a method for preparing a friction block for a washing machine brake shoe, comprising the following steps:

[0038] S1. Mixing the raw materials of the friction material: taking the friction material in proportion and placing it in a blender and stirring evenly;

[0039] S2. Hot pressing: placing the evenly mixed friction material into a hot press and pressing it to obtain a semi-finished friction block;

[0040] S3, grinding: grinding the hot-pressed friction block semi-finished product to the required thickness and curvature to obtain the friction block.

[0041] In step S1, the friction material comprises the following components, measured by volume percentage: 8% to 18% silicone resin, 12% to 18% powdered styrene-butadiene rubber, 15% to 25% mineral fiber, 18% to 28% graphite lubricant, 10% to 20% calcium silicate, and 10% to 15% aluminum oxide. Preferably, the friction material comprises the following components: 10% to 16% silicone resin, 14% to 16% powdered styrene-butadiene rubber, 18% to 22% mineral fiber, 20% to 26% graphite lubricant, 12% to 18% calcium silicate, and 11% to 14% aluminum oxide. More preferably, the friction material comprises the following components: 13% silicone resin, 15% powdered styrene-butadiene rubber, 20% mineral fiber, 24% graphite lubricant, 15% calcium silicate, and 13% aluminum oxide. In some embodiments, the mineral fiber comprises any one of wollastonite fiber, rock wool, and aluminum silicate fiber. For example, the organic silicone resin is a water-based organic silicone resin, the gel time of the water-based organic silicone resin at 150° C. is 120 seconds, and the pores of the calcium silicate are at the micron level.

[0042] When the mixer stirs the friction material, the speed of the blade of the mixer is 2000-3000 r / min, for example, 2000 r / min, 2500 r / min, 3000 r / min, or any other value within the range of 2000-3000 r / min; the stirring time is 10-15 minutes, for example, 10 minutes, 13 minutes, 15 minutes, or any other value within the range of 10-15 minutes.

[0043] In step S2, hot pressing is performed using a conventional hot press in the art. The hot pressing pressure is 3-5 MPa, for example, 3 MPa, 4 MPa, or 5 MPa, etc. The hot pressing temperature is 130-160°C, for example, 130°C, 140°C, 150°C, or 160°C, etc. The hot pressing time is 2-10 minutes, for example, 2 minutes, 5 minutes, 7 minutes, or 10 minutes, etc.

[0044] In step S3, the thickness and curvature of the friction block are adjusted according to actual needs.

[0045] The technical solutions of the present invention are described in detail below through several specific examples. Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by conventional methods in the art, and the instruments used in the examples are all commercially available.

[0046] Example 1

[0047] In this embodiment, the friction block is prepared as follows: (1) Mixing the raw materials of the friction material: Based on the volume percentage of the friction material, the friction material is measured according to the ratio of 13% water-based silicone resin, 15% powdered styrene-butadiene rubber, 20% mineral fiber, 24% graphite lubricant, 15% calcium silicate, and 13% aluminum oxide. The friction material is placed in a mixer and stirred at a speed of 2000 r / min for 15 minutes to mix the various components of the friction material uniformly. (2) Hot pressing: The uniformly mixed friction material is placed in a hot press and pressed into shape at a pressing pressure of 3 MPa, a hot pressing temperature of 130°C, and a hot pressing time of 10 minutes to obtain a friction block semi-finished product. (3) Grinding: The hot-pressed friction block semi-finished product is ground to the desired thickness and curvature to obtain a friction block. In this embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite, with the mass ratio of graphite powder, flake graphite, and granular graphite being 1:1:1. The mineral fiber is wollastonite fiber.

[0048] Example 2

[0049] In this embodiment, the friction block is prepared as follows: (1) Mixing the raw materials of the friction material: Based on the volume percentage of the friction material, the friction material is measured according to the ratio of 9% water-based silicone resin, 18% powdered styrene-butadiene rubber, 25% mineral fiber, 28% graphite lubricant, 10% calcium silicate, and 10% aluminum oxide. The friction material is placed in a mixer and stirred at a speed of 2500 r / min for 12 minutes to uniformly mix the various components of the friction material; (2) Hot pressing: The uniformly mixed friction material is placed in a hot press and pressed into shape at a pressing pressure of 4 MPa, a hot pressing temperature of 150°C, and a hot pressing time of 6 minutes to obtain a friction block semi-finished product; (3) Grinding: The hot-pressed friction block semi-finished product is ground to the desired thickness and curvature to obtain a friction block. In this embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite, with the mass ratio of graphite powder, flake graphite, and granular graphite being 1:1:1.5. The mineral fiber is selected from mineral rock wool.

[0050] Example 3

[0051] In this embodiment, the friction block is prepared as follows: (1) Mixing the raw materials of the friction material: Based on the volume percentage of the friction material, the friction material is measured according to the ratio of 8% water-based silicone resin, 12% powdered styrene-butadiene rubber, 17% mineral fiber, 28% graphite lubricant, 20% calcium silicate, and 15% aluminum oxide. The friction material is placed in a mixer and stirred at a speed of 3000 r / min for 11 minutes to uniformly mix the various components of the friction material; (2) Hot pressing: The uniformly mixed friction material is placed in a hot press and pressed into shape at a pressing pressure of 5 MPa, a hot pressing temperature of 160°C, and a hot pressing time of 2 minutes to obtain a friction block semi-finished product; (3) Grinding: The hot-pressed friction block semi-finished product is ground to the desired thickness and curvature to obtain a friction block. In this embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite, with the mass ratio of graphite powder, flake graphite, and granular graphite being 1:1.5:1.2. The mineral fiber is aluminum silicate fiber.

[0052] Example 4

[0053] In this embodiment, the friction block is prepared as follows: (1) Mixing the raw materials of the friction material: Based on the volume percentage of the friction material, the friction material is measured according to the ratio of 13% water-based silicone resin, 18% powdered styrene-butadiene rubber, 25% mineral fiber, 18% graphite lubricant, 16% calcium silicate, and 10% aluminum oxide; the friction material is placed in a mixer and stirred at a speed of 2700 r / min for 12 minutes to uniformly mix the various components of the friction material; (2) Hot pressing: The uniformly mixed friction material is placed in a hot press and pressed into shape at a pressing pressure of 4 MPa, a hot pressing temperature of 140°C, and a hot pressing time of 8 minutes to obtain a friction block semi-finished product; (3) Grinding: The hot-pressed friction block semi-finished product is ground to the desired thickness and curvature to obtain a friction block. In this embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite, with the mass ratio of graphite powder, flake graphite, and granular graphite being 1:1.3:1.2. The mineral fiber is aluminum silicate fiber.

[0054] Example 5

[0055] In this embodiment, the friction block is prepared as follows: (1) Mixing the raw materials of the friction material: Based on the volume percentage of the friction material, the friction material is measured according to the ratio of 18% water-based silicone resin, 18% powdered styrene-butadiene rubber, 15% mineral fiber, 28% graphite lubricant, 11% calcium silicate, and 10% aluminum oxide. The friction material is placed in a mixer and stirred at a speed of 3000 r / min for 10 minutes to uniformly mix the various components of the friction material; (2) Hot pressing: The uniformly mixed friction material is placed in a hot press and pressed into shape at a pressing pressure of 5 MPa, a hot pressing temperature of 130°C, and a hot pressing time of 6 minutes to obtain a friction block semi-finished product; (3) Grinding: The hot-pressed friction block semi-finished product is ground to the desired thickness and curvature to obtain a friction block. In this embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite, with the mass ratio of graphite powder, flake graphite, and granular graphite being 1:1.3:1.4. The mineral fiber is wollastonite fiber.

[0056] Example 6

[0057] In this embodiment, the friction block is prepared as follows: (1) Mixing the raw materials of the friction material: Based on the volume percentage of the friction material, the friction material is measured according to the ratio of 11% water-based silicone resin, 15% powdered styrene-butadiene rubber, 18% mineral fiber, 26% graphite lubricant, 18% calcium silicate, and 12% aluminum oxide. The friction material is placed in a mixer and stirred at a speed of 2800 r / min for 14 minutes to uniformly mix the various components of the friction material; (2) Hot pressing: The uniformly mixed friction material is placed in a hot press and pressed into shape at a pressing pressure of 4 MPa, a hot pressing temperature of 150°C, and a hot pressing time of 6 minutes to obtain a friction block semi-finished product; (3) Grinding: The hot-pressed friction block semi-finished product is ground to the desired thickness and curvature to obtain a friction block. In this embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite, with the mass ratio of graphite powder, flake graphite, and granular graphite being 1:1.3:1.3. The mineral fiber is wollastonite fiber.

[0058] Example 7

[0059] In this embodiment, the friction block is prepared as follows: (1) Mixing the raw materials of the friction material: Based on the volume percentage of the friction material, the friction material is measured according to the ratio of 16% water-based silicone resin, 16% powdered styrene-butadiene rubber, 20% mineral fiber, 20% graphite lubricant, 14% calcium silicate, and 14% aluminum oxide. The friction material is placed in a mixer and stirred at a speed of 2500 r / min for 12 minutes to uniformly mix the various components of the friction material; (2) Hot pressing: The uniformly mixed friction material is placed in a hot press and pressed into shape at a pressing pressure of 5 MPa, a hot pressing temperature of 140°C, and a hot pressing time of 5 minutes to obtain a friction block semi-finished product; (3) Grinding: The hot-pressed friction block semi-finished product is ground to the desired thickness and curvature to obtain a friction block. In this embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite, with the mass ratio of graphite powder, flake graphite, and granular graphite being 1:1.3:1.2. The mineral fiber is selected from mineral rock wool.

[0060] Example 8

[0061] In this embodiment, the friction block is prepared as follows: (1) Mixing the raw materials of the friction material: Based on the volume percentage of the friction material, the friction material is measured according to the ratio of 10% water-based silicone resin, 14% powdered styrene-butadiene rubber, 22% mineral fiber, 25% graphite lubricant, 18% calcium silicate, and 11% aluminum oxide. The friction material is placed in a mixer and stirred at a speed of 3000 r / min for 11 minutes to uniformly mix the various components of the friction material; (2) Hot pressing: The uniformly mixed friction material is placed in a hot press and pressed into shape at a pressing pressure of 3 MPa, a hot pressing temperature of 130°C, and a hot pressing time of 10 minutes to obtain a friction block semi-finished product; (3) Grinding: The hot-pressed friction block semi-finished product is ground to the desired thickness and curvature to obtain a friction block. In this embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite, with the mass ratio of graphite powder, flake graphite, and granular graphite being 1:1.2:1.2. The mineral fiber is selected from mineral rock wool.

[0062] Example 9

[0063] In this embodiment, the friction block is prepared as follows: (1) Mixing the raw materials of the friction material: Based on the volume percentage of the friction material, the friction material is measured according to the ratio of 14% water-based silicone resin, 15% powdered styrene-butadiene rubber, 20% mineral fiber, 26% graphite lubricant, 12% calcium silicate, and 13% aluminum oxide. The friction material is placed in a mixer and stirred at a speed of 2700 r / min for 12 minutes to uniformly mix the various components of the friction material; (2) Hot pressing: The uniformly mixed friction material is placed in a hot press and pressed into shape at a pressing pressure of 4 MPa, a hot pressing temperature of 140°C, and a hot pressing time of 8 minutes to obtain a friction block semi-finished product; (3) Grinding: The hot-pressed friction block semi-finished product is ground to the desired thickness and curvature to obtain a friction block. In this embodiment, the graphite lubricant includes graphite powder, flake graphite, and granular graphite, with the mass ratio of graphite powder, flake graphite, and granular graphite being 1:1.2:1.2. The mineral fiber is wollastonite fiber.

[0064] The gel time of the waterborne silicone resin in Examples 1 to 9 at 150° C. is 120 s.

[0065] The friction blocks prepared in Examples 1 to 9 were bonded to a steel backing by applying glue and then baked in a constant temperature oven at 200°C for 3 hours. After removal, the blocks were naturally cooled to room temperature to produce washing machine brake shoes. The density, shear strength, bending strength, friction coefficient, and wear rate of the washing machine brake shoes were tested in accordance with GB / T 11834. The washing machine brake shoes were then assembled into a complete washing machine and subjected to fatigue and noise testing. The test results are shown in Table 1.

[0066] Table 1 Density, shear strength, bending strength, friction performance, fatigue test, and noise test of brake shoes prepared using the friction blocks of Examples 1 to 9

[0067]

[0068] The friction material for the brake shoe of the washing machine of the present invention is a combination of rubber and silicone resin as a binder to form a material matrix, which can improve the elasticity of the friction material. The combination of rubber and calcium silicate can increase the porosity of the friction material and reduce the braking noise of the friction material. Furthermore, the silicone resin in the friction material adopts a water-based silicone resin, which can greatly reduce the emission of volatile organic compounds and improve the environmental friendliness of the friction material. The friction block made using the friction material of the present application has smooth braking, quietness, long service life and can extend the service life of the braking pair, and is suitable for the brake shoe of the washing machine. In addition, the method for preparing the friction block of the present invention is simple in process, highly operable, low in equipment cost, high in production efficiency, and the friction block has a low wear rate and high shear resistance, which ensures the safety and durability of the washing machine during operation, and also improves the user experience. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and significance.

[0069] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A friction material for a washing machine brake shoe, characterized in that: Calculated by volume percentage of the friction material, the friction material includes the following components: 8% to 18% of silicone resin, 12% to 18% of powdered styrene-butadiene rubber, 15% to 25% of mineral fiber, 18% to 28% of graphite lubricant, 10% to 20% of calcium silicate, and 10% to 15% of aluminum oxide.

2. The friction material for a washing machine brake shoe according to claim 1, characterized in that: Calculated by volume percentage, the friction material includes the following components: 10% to 16% of silicone resin, 14% to 16% of powdered styrene-butadiene rubber, 18% to 22% of mineral fiber, 20% to 26% of graphite lubricant, 12% to 18% of calcium silicate, and 11% to 14% of aluminum oxide.

3. The friction material for a washing machine brake shoe according to claim 1, characterized in that: The graphite lubricant includes graphite powder, flake graphite and granular graphite, and the mass ratio of the graphite powder, the flake graphite and the granular graphite is 1:(1-1.5):(1-1.5).

4. The friction material for a washing machine brake shoe according to claim 3, characterized in that: The particle size of the graphite powder is 50-80 μm, and the particle size of the granular graphite is 150-550 μm.

5. The friction material for a washing machine brake shoe according to claim 1, characterized in that: The mineral fiber includes any one of wollastonite fiber, mineral rock wool, and aluminum silicate fiber.

6. The friction material for a washing machine brake shoe according to claim 1, characterized in that: The particle size of the calcium silicate is 3 to 50 μm.

7. A friction block for a washing machine brake shoe, characterized in that: The friction block is made of the friction material according to any one of claims 1 to 6.

8. A method for preparing a friction block for a washing machine brake shoe, characterized in that: The following steps are involved: Mixing the raw materials of the friction material: taking the friction material according to any one of claims 1 to 6 in proportion and placing it in a blender and stirring it evenly; Hot pressing molding: put the evenly mixed friction material into a hot press and press it into shape to obtain a semi-finished friction block; Grinding: Grinding the hot-pressed friction block semi-finished product to a desired thickness and curvature to obtain a friction block.

9. The preparation method according to claim 8, characterized in that The blade speed of the mixer is 2000-3000 r / min, and the stirring time is 10-15 minutes.

10. The preparation method according to claim 8, characterized in that The pressing pressure of the hot pressing molding is 3-5 MPa, the hot pressing temperature is 130-160° C., and the hot pressing time is 2-10 minutes.

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