Manufacturing method of friction plate for point switch

Abstract

The invention relates to the technical field of switch machines, and discloses a manufacturing method of a friction plate for a switch machine, which comprises the following steps of: preparing materials required by a middle reinforced substrate according to a set ratio, and mixing the materials; a layer of friction material is firstly loaded into a pressing machine, then a layer of middle reinforcing base plate mixed material is loaded, then a layer of friction material is loaded, and the three layers of materials are integrally pressed to form a pressed blank; then the pressed blank is subjected to pressure sintering; the overall strength of the product can be improved through integral forming, and in the subsequent sintering step, the integrally-formed pressed blank is not prone to dislocation. The material of the middle reinforced substrate and the friction material are pressed together to form the friction plate, the substrate does not need to be prepared firstly and then the friction plate does not need to be prepared, the production process of the product is simplified, the production efficiency is improved, and meanwhile it can be guaranteed that the reject ratio is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of railway switch machines, in particular to a method for manufacturing a friction plate for a switch machine. Background Art

[0002] The switch machine is used to change the direction of the turnout opening, lock the turnout point rail, and reflect the position status of the point rail. It is widely used in railway turnout conversion. During the use of the switch machine, the output force of the switch machine is adjusted by adjusting the friction torque of the friction coupling, so that the output force is controlled within a safe range that does not damage the track and ensures the track turning. During the process of the switch machine switching the turnout, if the turnout encounters an obstacle and cannot fit closely, the friction coupling will enter the friction state to protect the switch machine. At the same time, if the output force of the switch machine is too small, the switch machine will not be able to overcome the turnout resistance to switch the turnout, so the friction coupling can provide a stable friction limiting force, which plays an important role in the reliable operation of the switch machine.

[0003] In the prior art, the friction plate of the switch machine is generally made of copper-based powder metallurgy friction material bonded to a steel reinforced substrate. The switch machine structure is a circular thin sheet with a slot in the middle. During production, the steel reinforced substrate needs to be processed first and copper plated on the surface to ensure the bonding strength. After that, the friction material is bonded to both sides of the steel substrate and sintered as a whole to obtain the desired product. The traditional process for making the friction plate of the switch machine has many production steps, and it is easy to cause misalignment during sintering, resulting in a large number of defective green products during the molding process; and the bonding process is slow, which seriously affects the production efficiency of the product. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for manufacturing a friction plate for a switch machine, by adjusting the production process of the intermediate reinforcing substrate of the friction plate in the switch machine, changing the steel substrate to an iron-based powder metallurgy substrate, and by adjusting the types and proportions of powder elements for the substrate, while ensuring that the overall strength of the product is not reduced, the product production efficiency and yield rate are improved, the bonding strength between the friction material and the substrate is improved, and the copper plating process of the substrate with greater pollution is omitted.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A method for manufacturing a friction plate for a switch machine comprises the following steps:

[0007] The material ratio of the friction material remains unchanged, and the materials required for the intermediate reinforcement substrate are prepared and mixed according to the set ratio;

[0008] Firstly, a layer of friction material is loaded into the press, then a layer of intermediate reinforcing substrate mixture is loaded, and then a layer of friction material is loaded, and the three layers of materials are integrally pressed to form a compact; then, the compact is pressurized and sintered.

[0009] As a further implementation method, the material components of the intermediate reinforcement substrate are: 40-65% reduced iron powder, 10-20% manganese iron alloy powder, 10-20% copper iron alloy powder, 10-15% phosphorus iron alloy powder, 1-5% zinc powder, and 0.1-1% graphite powder.

[0010] As a further implementation, the friction material is a uniformly mixed copper-based powder.

[0011] As a further implementation manner, a mixer is used to mix the materials required for the intermediate reinforcing substrate.

[0012] As a further implementation, the mixer has a rotation speed of 35 r / min and a mixing time of not less than 200 min.

[0013] As a further implementation method, the three-layer material is integrally pressed into shape using a press with a pressure of 400-500 MPa for a time of not less than 10 seconds.

[0014] As a further implementation method, the formed compact is placed in a protective atmosphere sintering furnace for pressure sintering, and then cooled to obtain a friction plate green compact.

[0015] As a further implementation, the sintering temperature is 850-950° C., the sintering pressure is about 3-5 MPa, and the sintering time is 60-240 minutes.

[0016] As a further implementation, the sintering is performed in an ammonia decomposition reducing atmosphere.

[0017] As a further implementation method, the friction plate blank obtained after sintering is machined to obtain a finished friction plate.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The present invention puts the material of the intermediate reinforcing substrate and the friction material into a press for integral pressing. The integral pressing can improve the overall strength of the product, and in the subsequent sintering step, the integrally formed compact is not prone to misalignment, so that the defective rate of the produced product is reduced. This integral molding method does not require the preparation of the substrate first and then the friction plate, so that the production process of the product is simplified, which improves production efficiency and ensures that the defective rate is reduced.

[0020] 2. The sintering process of the present invention does not require bonding, the production process is reduced, and there is no risk of missed bonding and other adverse risks. In addition, the bonding strength between the intermediate substrate layer and the friction layer of this one-piece pressed friction plate is higher, and the material shear strength exceeds 100MPa, which fully meets the use requirements of the product; the molding process is completed in one step by the equipment, and the molding efficiency is about 1 minute / piece, which is far higher than the efficiency of the overall bonding after two moldings.

[0021] 3. The intermediate reinforcing substrate involved in the present invention is prepared by integrally forming and sintering after mixing metal powders, which not only improves the bonding strength between the reinforcing substrate and the friction material, but also eliminates the highly polluting copper plating process of the steel substrate, making the entire production process more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 Schematic diagram of the structure of the friction plate in the embodiment of the present invention.

[0024] In the figure: the distances or sizes between parts are exaggerated to show the positions of various parts, and the schematic diagram is for reference only. DETAILED DESCRIPTION

[0025] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0026] Embodiment 1:

[0027] In a typical embodiment of the present invention, reference is made to Figure 1 As shown, a method for manufacturing a friction plate for a switch machine includes the following steps: preparing materials required for an intermediate reinforcing substrate according to a set ratio and mixing the materials; first loading a layer of friction material into a press, then loading a layer of the intermediate reinforcing substrate mixture, and then loading a layer of friction material, and pressing the three layers of materials as a whole to form a compact; then pressurizing and sintering the compact.

[0028] The material ratio of the intermediate reinforcement substrate is as follows:

[0029] 40% reduced iron powder, 19% ferromanganese powder, 20% ferrocopper powder, 15% ferrophosphorus powder, 5% zinc powder, 1% graphite powder; prepare two portions of friction material accordingly, and the amount of friction material is determined according to the specific situation.

[0030] The intermediate reinforcement substrate material is placed in a mixer, and the materials required for the intermediate reinforcement substrate are mixed by the mixer. The mixer speed is 35r / min, and the mixing time is 200min.

[0031] A layer of friction material, a layer of intermediate reinforcement substrate mixture, and a layer of friction material are sequentially loaded into the press, and then the press presses the three layers of materials as a whole to form a compact.

[0032] The formed compact is placed in a sintering furnace for pressure sintering at a temperature of 850°C, a sintering pressure of about 3 MPa, and a sintering time of 180 minutes in an ammonia decomposition reducing atmosphere. After sintering, the inner and outer diameters of the product are finely processed to obtain a finished friction plate.

[0033] After verification, under this process, the enhanced substrate material involved in this embodiment has a similar sintering shrinkage rate as the copper-based friction material, and does not cause other pollution or changes to the friction material. The shear strength of the finished friction plate material is 140MPa-200MPa, which meets the product use requirements. The bonding strength between the powder metallurgy enhanced substrate and the friction material is more than 60MPa, which is far greater than the bonding strength between the copper-plated steel substrate and the friction material (about 20MPa-40MPa).

[0034] Embodiment 2

[0035] Prepare the intermediate reinforcement substrate material, the material ratio is as follows:

[0036] 56% reduced iron powder, 15% ferromanganese powder, 15% ferrocopper powder, 10% ferrophosphorus powder, 3% zinc powder, 1% graphite powder; prepare two portions of friction material accordingly, and the amount of friction material is determined according to the specific situation.

[0037] The intermediate reinforcement substrate material is placed in a mixer, and the materials required for the intermediate reinforcement substrate are mixed by the mixer. The mixer speed is 35r / min, and the mixing time is 200min.

[0038] A layer of friction material, a layer of intermediate reinforcement substrate mixture, and a layer of friction material are sequentially loaded into the press, and then the press presses the three layers of materials as a whole to form a compact.

[0039] The formed compact is placed in a sintering furnace for pressure sintering at a temperature of 900°C, a pressure of about 5MPa, and a sintering time of 180 minutes in an ammonia decomposition reduction atmosphere. After sintering, the inner and outer diameters of the product are finely processed to obtain the finished friction plate;

[0040] After verification, the shear strength of the finished friction plate material is 150MPa-200MPa, and the bonding strength between the substrate and the friction material is above 80MPa, which meets the use requirements of the switch machine friction plate under the sintering conditions.

[0041] Embodiment three:

[0042] The material ratio of the intermediate reinforcement substrate is as follows:

[0043] 65% reduced iron powder, 10% ferromanganese powder, 13% ferrocopper powder, 10% ferrophosphorus powder, 1.9% zinc powder, 0.1% graphite powder; prepare two portions of friction material accordingly, and the amount of friction material is determined according to the specific situation.

[0044] The intermediate reinforcement substrate material is placed in a mixer, and the materials required for the intermediate reinforcement substrate are mixed by the mixer. The mixer speed is 35r / min, and the mixing time is 200min.

[0045] A layer of friction material, a layer of intermediate reinforcement substrate mixture, and a layer of friction material are sequentially loaded into the press, and then the press presses the three layers of material as a whole to form a compact. It should be noted that each time a layer of material is put in, the layer of material needs to be leveled and compacted.

[0046] The formed compact is placed in a sintering furnace for pressure sintering at a temperature of 950°C, a sintering pressure of about 3 MPa, and a sintering time of 180 minutes in an ammonia decomposition reducing atmosphere. After sintering, the inner and outer diameters of the product are finely processed to obtain a finished friction plate.

[0047] After verification, the shear strength of the finished friction plate material is 120MPa-180MPa, and the bonding strength between the substrate and the friction material is above 60MPa, which meets the use requirements of the switch machine friction plate under the sintering conditions.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a friction plate for a switch machine, characterized in that: The steps include: Prepare and mix the materials required for the intermediate reinforcement substrate according to the set ratio; Firstly, a layer of friction material is loaded into the press, then a layer of intermediate reinforcing substrate mixture is loaded, and then a layer of friction material is loaded, and the three layers of materials are integrally pressed to form a compact; then, the compact is pressurized and sintered.

2. The method for manufacturing a friction plate for a switch machine according to claim 1, characterized in that: The material components of the intermediate strengthening substrate are: 40-65% reduced iron powder, 10-20% manganese iron alloy powder, 10-20% copper iron alloy powder, 10-15% phosphorus iron alloy powder, 1-5% zinc powder, and 0.1-1% graphite powder.

3. The method for manufacturing a friction plate for a switch machine according to claim 1, characterized in that: The friction material is copper-based powder.

4. The method for manufacturing a friction plate for a switch machine according to claim 1, characterized in that: The materials required for the intermediate reinforcing substrate are mixed using a mixer.

5. The method for manufacturing a friction plate for a switch machine according to claim 4, characterized in that: The mixer has a rotation speed of 35 r / min and a mixing time of not less than 200 min.

6. The method for manufacturing a friction plate for a switch machine according to claim 1, characterized in that: The three layers of material are pressed into shape as a whole using a press with a pressure of 400-500 MPa for a period of not less than 10 seconds.

7. The method for manufacturing a friction plate for a switch machine according to claim 6, characterized in that: The formed green compact is placed in a protective atmosphere sintering furnace for pressure sintering, and then cooled to obtain a friction plate green compact.

8. The method for manufacturing a friction plate for a switch machine according to claim 7, characterized in that: The sintering temperature is 850-950°C, the sintering pressure is about 3-5MPa, and the sintering time is 60-240 minutes.

9. The method for manufacturing a friction plate for a switch machine according to claim 8, characterized in that: Sintering is carried out in an ammonia decomposition reducing atmosphere.

10. The method for manufacturing a friction plate for a switch machine according to claim 1, characterized in that: The friction plate blank obtained after sintering is machined to obtain a finished friction plate.

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