Brake shoe block and preparation method thereof

Abstract

The embodiment of the invention provides a brake shoe block and a preparation method. The brake shoe comprises the following components in parts by weight: 20-35 parts of a reinforcing agent, 19-26 parts of an adhesive, 25-30 parts of a friction reducing agent and 15-25 parts of a friction increasing agent, the antifriction agent comprises at least one of graphite and talcum powder. The method comprises the following steps: raw material filling: uniformly mixing raw materials according to a formula ratio, and filling a mold with the mixture; and shoe block pressing is conducted, specifically, the shoe block is pressed under the conditions that the mold temperature is 180-220 DEG C and the mold pressure (mold clamping force) is 18-25 MPa, and the mold heat preservation and pressure maintaining time is 3-10 minutes. Therefore, the friction coefficient of the brake shoe can be reduced, the high temperature resistance of the brake shoe is improved, the wear resistance of the brake shoe is improved, and the service life is prolonged.

Description

Technical Field

[0001] The exemplary embodiments of the present disclosure generally relate to the field of brake shoes, and particularly to brake shoes and preparation methods thereof. Background Art

[0002] The brake shoe is one of the key parts in the braking system of a vehicle (such as a bicycle, an electric bicycle, or an automobile, etc.). During the braking process of the vehicle, the brake shoe will expand to both sides under the action of the brake wheel cylinder, thereby playing a role in decelerating and stopping.

[0003] In the field of shared vehicles, due to the high usage frequency of the vehicles. However, the traditional brake shoes have a relatively high wear rate and are prone to premature aging, resulting in a short service life, increasing the frequency of operation and maintenance as well as the maintenance cost. Summary of the Invention

[0004] In a first aspect of the present disclosure, a brake shoe is provided. The brake shoe, by weight parts, comprises: 20 - 35 parts of a reinforcing agent, 19 - 26 parts of an adhesive, 25 - 30 parts of an anti-friction agent, and 15 - 25 parts of a friction-increasing agent; the anti-friction agent comprises at least one of graphite and talcum powder.

[0005] In some embodiments, the anti-friction agent may comprise graphite and talcum powder. Preferably, the weight ratio of graphite to talcum powder may be 0.8 - 1.2:1. More preferably, the weight ratio of graphite to talcum powder may be 1:1.

[0006] By reducing the dosage of the anti-friction agent and increasing the dosage of the anti-friction agent, the friction coefficient of the brake shoe can be reduced, thereby prolonging the service life of the brake shoe. At the same time, the braking sensitivity of the brake shoe applied to the vehicle is also reduced, thereby reducing the possibility of emergency braking.

[0007] On the other hand, by selecting graphite and talcum powder as the components of the anti-friction agent and adjusting the dosage ratio of graphite and talcum powder, the stability and wear resistance of the brake shoe can be improved. On the other hand, it also makes the reduction amplitude of the friction coefficient of the brake shoe at high temperature (for example, 150 °C) small, and the brake shoe can also maintain good braking ability at high temperature.

[0008] In some embodiments, the anti-friction agent further comprises molybdenum disulfide.

[0009] In some embodiments, the friction-increasing agent comprises at least one of wollastonite and corundum.

[0010] In some embodiments, the reinforcing agent comprises aramid.

[0011] In some embodiments, the adhesive comprises at least one of rubber and resin.

[0012] In some embodiments, by weight parts, the brake shoe block further comprises 0.5 - 1 part of a regulator; the regulator comprises at least one of a release agent and a flame retardant.

[0013] In some embodiments, by weight parts, the brake shoe block further comprises 1.5 - 2.5 parts of an auxiliary additive;

[0014] The auxiliary additive comprises at least one of copper powder, aluminum powder, and cashew shell oil friction powder.

[0015] In some embodiments, by weight parts, the brake shoe block comprises 28 parts of a reinforcing agent, 22 parts of an adhesive, 27 parts of an anti-friction agent, 20 parts of a friction-increasing agent, 1 part of a regulator, and 2 parts of an auxiliary additive.

[0016] In some embodiments, by weight percentage, the brake shoe block comprises 28 wt% of a reinforcing agent, 22 wt% of a binder, 27 wt% of an anti-friction agent, 20 wt% of a friction-increasing agent, 1 wt% of a regulator, and 2 wt% of an auxiliary additive.

[0017] In some embodiments, by weight parts, the brake shoe block comprises 28 parts of aramid, 11 parts of rubber, 11 parts of resin, 14 parts of graphite, 13 parts of talcum powder, 20 parts of wollastonite, 0.5 part of a release agent, 0.5 part of a flame retardant, 0.5 part of copper powder, 0.5 part of aluminum powder, and 1 part of rubber powder.

[0018] The brake shoe block provided according to the embodiments of the present disclosure reduces the amount of the friction-increasing agent and increases the amount of the anti-friction agent, thereby reducing the friction coefficient of the brake shoe block. At the same time, the present disclosure also adjusts the component ratio of the brake shoe block, which not only overcomes the problem of reduced stability of the brake shoe block caused by reducing the friction-increasing agent and increasing the anti-friction agent, but also further improves the overall stability after brake pressing, thereby improving the wear resistance of the brake shoe block, and thus extending the service life of the brake shoe block. In addition, the brake shoe block according to the present disclosure also has the advantage that the friction coefficient decays slowly at high temperatures, so that after long-term braking of the vehicle, a stable friction performance can still be maintained between the brake shoe block and the brake disc, thereby ensuring the reliability of the vehicle during long-term braking.

[0019] In a second aspect of the present disclosure, a method for preparing a brake shoe block is provided. The method includes: raw material filling, taking the raw materials in the formula amount, mixing them evenly and filling them into a mold; shoe block pressing, pressing the shoe block under the conditions that the mold temperature is 180 - 220 °C and the mold pressure (clamping force) is 18 - 25 MPa, and the mold heat preservation and pressure holding time is 3 - 10 minutes.

[0020] In some embodiments, the mold temperature is preferably 195 - 205 °C.

[0021] In some embodiments, the mold pressure (clamping force) is preferably 20 MPa.

[0022] In some embodiments, the heat preservation and pressure holding time of the mold is preferably 3 - 4 minutes.

[0023] It should be understood that the content described in this part is not intended to define the key features or important features of the embodiments of the present disclosure, nor is it used to limit the scope of the present disclosure. Other features of the present disclosure will become easily understandable through the following description. Detailed Description of Specific Embodiments

[0024] Embodiments of the present disclosure will be described in detail below. It should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present disclosure. It should be understood that the embodiments of the present disclosure are only for exemplary purposes and are not used to limit the protection scope of the present disclosure.

[0025] It should be noted that the titles of any sections / subsections provided herein are not restrictive. Various embodiments are described throughout this document, and any type of embodiment can be included under any section / subsection. In addition, the embodiments described in any section / subsection can be combined with any other embodiments described in the same section / subsection and / or different sections / subsections in any way.

[0026] In the description of the embodiments of the present disclosure, the term "comprising" and its like terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The term "some embodiments" should be understood as "at least some embodiments". There may also be other explicit and implicit definitions hereinafter. The terms "first", "second", etc. may refer to different or the same objects. There may also be other explicit and implicit definitions hereinafter.

[0027] As briefly mentioned above, in some shared bicycles, the tires used are solid tires (i.e., non-inflatable tires). The texture of this kind of tire is relatively hard, and the existing brake shoe blocks have a relatively high friction coefficient. When users are using them, they are prone to sudden braking, which may cause the wheels to slip on the ground, thus bringing certain risks.

[0028] On the other hand, due to the too high friction coefficient of the existing brake shoe blocks, the service life of the brake shoe blocks is also relatively short.

[0029] Based on the above problems, if simply reducing the dosage of the friction-increasing agent and / or increasing the dosage of the friction-reducing agent in the brake shoe block formula, it is likely to lead to a decrease in the internal bonding stability during the pressing process of the brake shoe block, thereby making the brake shoe block more prone to wear. On the one hand, this easily affects the reliability of the vehicle's braking, and on the other hand, it also reduces the wear resistance of the brake shoe block.

[0030] According to an embodiment of the present disclosure, a brake shoe block and a preparation method are proposed to solve or at least partially solve the above problems and other potential problems existing in the traditional solutions. According to various embodiments of the present disclosure, by appropriately reducing the dosage of the friction-increasing agent and increasing the dosage of the friction-reducing agent, the friction coefficient of the brake shoe block is adjusted to a more reasonable range, thereby improving the service life of the brake shoe block. On the other hand, by changing the proportion of each component in the brake shoe and selecting talc powder and graphite as the friction-reducing agent, the stability of the brake shoe block after pressing is also improved, thereby enhancing the wear resistance of the brake shoe block. It avoids problems such as a decrease in the stability of the brake shoe block caused by only adjusting the dosages of the friction-increasing agent and the friction-reducing agent, and the brake shoe block being prone to breakage and fragmentation during use.

[0031] The brake shoe block provided according to an embodiment of the present disclosure mainly includes a reinforcing agent, an adhesive, a friction-reducing agent, a friction-increasing agent, and corresponding additives.

[0032] In some embodiments, the reinforcing agent may include aramid. For example, at least one of para-aramid and meta-aramid can be selected.

[0033] In some embodiments, the adhesive may include resin, such as phenolic resin, etc. In some other embodiments, the adhesive may also include rubber. For example, the adhesive can be a mixture of resin and rubber. In some specific embodiments, the weight ratio of the resin to the vulcanized rubber solution can be 5:1. Adding rubber to the adhesive can appropriately increase the friction force of the brake shoe block and reduce the noise generated when the brake shoe block brakes.

[0034] In some embodiments, the friction-reducing agent may include graphite and / or talc powder.

[0035] In some embodiments, both graphite and talc powder can be used alone as the friction-reducing agent. In some other embodiments, graphite and talc powder can also be used in combination. In some preferred embodiments, when graphite and talc powder are used in combination as the friction-reducing agent, the weight ratio of graphite to talc powder can be 0.8 - 1.2:1.

[0036] Furthermore, in some alternative embodiments, the friction-reducing agent may further include molybdenum disulfide.

[0037] In some embodiments, the friction-increasing agent includes wollastonite and / or corundum. Preferably, the particle size of the friction-increasing agent may not be greater than 0.05 mm.

[0038] In some embodiments, the brake shoe block may further include a regulator, and the regulator may be at least one of a release agent or a flame retardant.

[0039] In some embodiments, the release agent may include at least one of silicone oil, toluene solution of silicone rubber, and synthetic paraffin.

[0040] In some embodiments, the flame retardant may include at least one of magnesium hydroxide, antimony trioxide, and aluminum hydroxide.

[0041] In some embodiments, the brake shoe block may further include some auxiliary additives, and the auxiliary additives include at least one of copper powder, aluminum powder, and friction powder of cashew shell oil.

[0042] In some embodiments, the auxiliary additives may further include copper fiber.

[0043] These auxiliary additives can play a certain filling role, thereby improving the internal bonding stability after the brake shoe block is pressed. At the same time, the auxiliary additives can also improve the heat conduction performance of the brake shoe block, which is beneficial to the rapid heat dissipation of the brake shoe block, and reduce the loss of the friction coefficient of the brake shoe block at high temperatures.

[0044] According to an embodiment of the present disclosure, a method for preparing a brake shoe block is also provided, including: raw material loading, taking a formula amount of raw materials, mixing them evenly, and filling them into a mold.

[0045] Shoe block pressing, pressing the shoe block under the conditions that the mold temperature is 180 - 220 °C and the mold pressure (clamping force) is 18 - 25 MPa, and the mold heat preservation and pressure holding time is 3 - 10 minutes.

[0046] Further, in some embodiments, the mold temperature may be 195 - 205 °C.

[0047] Further, in some embodiments, the mold pressure (clamping force) is 20 MPa.

[0048] Further, in some embodiments, the mold heat preservation and pressure holding time is 3 - 4 minutes.

[0049] By adjusting the parameters in the method for preparing the brake shoe block, the prepared brake shoe block has higher stability, so that it can maintain a stable working state under harsh working environments (such as high temperature, sudden cooling, being wrapped by sediment, etc.), and at the same time has high wear resistance. Therefore, the service life of the brake shoe block can be extended.

[0050] Hereinafter, the brake shoe block of the present disclosure will be further described in conjunction with specific embodiments.

[0051] Embodiment 1

[0052] A brake shoe block, comprising 28 g of aramid, 11 g of rubber, 11 g of resin, 14 g of graphite, 13 g of talcum powder, 20 g of wollastonite, 0.5 g of mold release agent, 0.5 g of flame retardant, 1 g of copper powder, and 1 g of aluminum powder.

[0053] After mixing the above raw materials evenly, fill them into a mold, and under the conditions of a mold temperature of 200 ± 5 °C and a mold pressure of 20 MPa, keep warm and pressure for 4 minutes.

[0054] Example 2

[0055] A brake shoe block, comprising 27.3 g of aramid, 11 g of rubber, 11 g of resin, 15 g of graphite, 14.5 g of talcum powder, 18.2 g of wollastonite, 0.5 g of mold release agent, 0.5 g of flame retardant, 1 g of copper powder, and 1 g of aluminum powder.

[0056] After mixing the above raw materials evenly, fill them into a mold, and under the conditions of a mold temperature of 200 ± 5 °C and a mold pressure of 20 MPa, keep warm and pressure for 3 minutes.

[0057] Example 3

[0058] A brake shoe block, comprising 28.5 g of aramid, 11 g of rubber, 11 g of resin, 16.5 g of graphite, 16 g of talcum powder, 14 g of wollastonite, 0.5 g of mold release agent, 0.5 g of flame retardant, 1 g of copper powder, and 1 g of aluminum powder.

[0059] After mixing the above raw materials evenly, fill them into a mold, and under the conditions of a mold temperature of 200 ± 5 °C and a mold pressure of 20 MPa, keep warm and pressure for 3 minutes.

[0060] Comparative Example 1

[0061] A brake shoe block, comprising 24.5 g of aramid, 11 g of rubber, 11 g of resin, 11.5 g of graphite, 11 g of talcum powder, 28 g of wollastonite, 0.5 g of mold release agent, 0.5 g of flame retardant, 1 g of copper powder, and 1 g of aluminum powder.

[0062] After mixing the above raw materials evenly, fill them into a mold, and under the conditions of a mold temperature of 350 ± 5 °C and a mold pressure of 20 MPa, keep warm and pressure for 5 minutes.

[0063] Performance testing of the brake shoe block.

[0064] 1. Friction coefficient of the brake shoe block.

[0065] Test with gray cast iron HT250 as the paired brake disc, and detect the friction coefficient of the brake shoe block at 100 °C and 150 °C respectively.

[0066] 2. Wear resistance of the brake shoe block.

[0067] Under the conditions of a load of 80 kg, a braking time of 24 seconds, and a test speed of 20 km / h, the wear thickness of the brake shoe after 10,000 brake applications is detected.

[0068] The test results of Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0069] Table 1

[0070] Group Coefficient of friction (100°C) Coefficient of friction (150°C) Wear thickness Example 1 0.22 0.19 ≤0.3 mm Example 2 0.2 0.15 ≤0.28 mm Example 3 0.18 0.1 ≤0.20 mm Comparative Example 1 0.35 0.06 ≤0.45 mm

[0071] It can be seen from Examples 1-3, Comparative Example 1 and in combination with Table 1 that the brake shoe provided by the present disclosure has a lower friction coefficient in an environment of 100°C, and for the brake shoes of Examples 1-3, the friction coefficient decreases little with the increase of temperature, thus having better high-temperature resistance. At the same time, because the brake shoe of the present disclosure has a lower friction coefficient and good high-temperature resistance in an environment of 100°C, and the brake shoe has high stability, the brake shoe of the present disclosure has higher wear resistance, so that the service life of the brake shoe is longer. This brake module is applied in the field of shared bicycles, which can extend the maintenance cycle and reduce the operation and maintenance costs.

[0072] The various implementations of the present disclosure have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed implementations. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described implementations. The selection of the terms used herein is intended to best explain the principles of the implementations, the practical application, or the improvement of the technology in the market, or to enable other ordinary skill in the technical field to understand the various implementation manners disclosed herein.

Claims

1. A brake shoe, by weight, comprising: 20 - 35 parts of reinforcing agent, 19 - 26 parts of binder, 25 - 30 parts of anti-friction agent, 15 - 25 parts of friction-increasing agent; The anti-friction agent includes at least one of graphite and talcum powder.

2. The brake shoe according to claim 1, wherein the anti-friction agent includes graphite and talcum powder, and the weight ratio of the graphite to the talcum powder is 0.8 - 1.2:

1.

3. The brake shoe according to claim 2, wherein the anti-friction agent further includes molybdenum disulfide.

4. The brake shoe according to claim 1, wherein the friction-increasing agent includes at least one of wollastonite and corundum.

5. The brake shoe according to claim 1, wherein the reinforcing agent includes aramid.

6. The brake shoe according to claim 1, wherein the binder includes at least one of rubber and resin.

7. The brake shoe according to any one of claims 1 - 6, further comprising 0.5 - 1 part of regulator by weight; The regulator includes at least one of mold release agent and flame retardant.

8. The brake shoe according to any one of claims 1 - 6, further comprising 1.5 - 2.5 parts of auxiliary additive by weight; The auxiliary additive includes at least one of copper powder, aluminum powder, and cashew shell oil friction powder.

9. The brake shoe according to any one of claims 1 - 6, comprising 28 parts of reinforcing agent, 22 parts of binder, 27 parts of anti-friction agent, 20 parts of friction-increasing agent, 1 part of regulator, and 2 parts of auxiliary additive by weight.

10. A method for preparing a brake shoe according to any one of claims 1 - 9, comprising: Raw material filling, taking the raw materials in the formula amount, mixing them evenly and filling them into a mold; Brake shoe pressing, pressing the brake shoe under the conditions that the mold temperature is 180 - 220 °C and the mold pressure is 18 - 25 MPa, and the mold heat preservation and pressure holding time is 3 - 10 minutes.

11. The preparation method according to claim 10, wherein the mold temperature is 195 - 205 °C.

12. The preparation method according to claim 10, wherein the mold pressure is 20 MPa.

13. The preparation method according to claim 10, wherein the mold heat preservation and pressure holding time is 3 - 4 minutes.