Contact group protection structure of switch machine

Abstract

The utility model discloses a protection structure for a contact group of a point switch, and aims to solve the problems of poor conductivity and unsatisfactory service life of the contact group of the existing point switch after long-term operation. According to the point switch contact group protection structure, a first plating layer and a second plating layer are respectively formed on the surfaces of a contact sheet body and a contact ring body through a ternary alloy plating technology. The ternary alloy plating technology is applied to the point switch contact group protection structure for the first time, the problems of arcing, oxidation, carbon deposition, powder falling and the like of a nickel plating process and a passivation process are solved, and the contact resistance is not changed and is smaller than 10 m omega in high-temperature, low-temperature and humid environments; surface oxidation and film formation can be prevented, scraping is prevented, the coating is not sensitive to collision, and surface gloss cannot be lost in the use process.

Description

TECHNICAL FIELD

[0001] The application relates to a switch machine contact group protection structure. BACKGROUND

[0002] The railway switch machine, as an execution mechanism of the turnout control system, undertakes important functions such as switching the locked turnout switch rail or the turnout stock rail, indicating the position and state of the turnout switch rail or the turnout stock rail in the interlocked area, and the like, and plays a vital role in ensuring the safety of railway operation and improving the efficiency of transportation.

[0003] The connection or disconnection of the turnout is realized by the clamping (closure) or disengaging (disconnection) of the movable contact group in the switch machine into (or out of) the static contact group, and the specific contact part is usually the static contact sheet and the movable contact ring, which is controlled to swing back and forth between the static contact sheets on the left and right sides. In order to enhance the clamping pressure, a flexible reinforcing sheet is usually arranged on the outside of the static contact sheet to abut against the static contact sheet from the outside.

[0004] However, the railway switch machine contact group may have the problem of unreliable conduction after long-term operation of frequent closure and disconnection. For this reason, many different attempts have been made by people in the industry, and the main improvement ideas are as follows:

[0005] I. Optimization of the material of the contact body

[0006] A more wear-resistant and better heat-conducting material is selected as the contact material to improve the durability and heat dissipation capacity of the contact. For example, a redundant contact group made of beryllium bronze material is used to improve the contact reliability of the movable and static contact groups.

[0007] II. Optimization of the shape of the static contact sheet

[0008] The arc / bent structure of the static contact sheet is optimized to strengthen the adaptation and fastening of the cylindrical surface of the movable contact ring.

[0009] III. Redundant configuration of the static contact sheet

[0010] Through the redundant design of the upper and lower layers of the static contact sheet, it is ensured that each contact post (movable contact ring) is connected with the corresponding static contact group.

[0011] However, after long-term operation of the railway switch machine contact group, the above measures may still result in poor conduction, and some of the measures have high costs.

[0012] The inventor realizes that, in addition to the changes in the structure of the contact sheet and the elasticity, the plating layer (currently, a nickel plating process is commonly used) itself also causes the problem of poor conduction after long-term operation of the railway switch machine contact group:

[0013] 1. During the frequent closing process of the contact group, when the current flows in the contact part between the stationary contact piece and the moving contact ring, it is easy to generate an electric arc, which leads to electrolytic corrosion on its surface and carbon accumulation. After repeated closing more than 3000 times, its contact resistance gradually increases from about 10mΩ until the contact resistance becomes infinite, indicating that the switch machine is broken.

[0014] 2. In humid climates, the nickel plating on contact plates and contact rings is prone to oxidation, which manifests as white powder on the plating surface, commonly known as "white fuzz". This leads to poor contact between the stationary contact plate and the moving contact ring, increased contact resistance, and reduced conductivity.

[0015] 3. Frequent closing of the stationary contact plate and the moving contact ring can easily generate black powder. If the contact assembly is not cleaned in time, its contact resistance will increase and its conductivity will decrease. At the same time, cleaning the contact assembly is relatively labor-intensive, which increases the difficulty of railway maintenance.

[0016] To address this factor, some literature proposes passivation treatment for the contact points, specifically by depositing a uniform, dense nickel plating layer on the copper component to form an extremely thin passivation film on the surface. However, after testing, the passivation method has the following problems:

[0017] 1. The passivation process has a relatively good conductivity, but in many humid areas, the contact group of this process is prone to oxidation, commonly known as "green mold". After oxidation, the static contact piece and the moving contact ring have poor contact and the conductivity decreases.

[0018] 2. The passivation process forms a very thin oxide layer on the surface of the body. Its disadvantage is that the wear resistance is not high. When applied to the working of switch machine contact groups, due to the large impact force, the oxide layer is basically worn away after about 3,000 cycles, exposing the body material and drastically reducing the service life of the contact group. Summary of the Invention

[0019] Therefore, this application provides a protection structure for switch machine contact groups to solve the problems of poor conductivity and unsatisfactory service life of existing switch machine contact groups after long-term operation.

[0020] To achieve the above objectives, this application provides the following technical solution:

[0021] A switch machine contact group protection structure includes a stationary contact group and a moving contact group, wherein the contact unit of the stationary contact group is a contact piece, and the contact unit of the moving contact group is a contact ring; the special feature is that the contact piece includes a contact piece body, and the surface of the contact piece body is formed with a first coating by a ternary alloy plating technology; the contact ring includes a contact ring body, and the surface of the contact ring body is formed with a second coating by a ternary alloy plating technology.

[0022] The ternary alloy plating technology is the prior art, but is currently mainly applied to the surface treatment of coaxial connectors, filters, waveguides, microwave devices and other radio frequency devices, and is used to improve the signal transmission performance by virtue of the excellent electrical conductivity, good high-frequency characteristics and cross modulation characteristics.

[0023] Optionally, the thickness of the first plating layer is 6-8 μm.

[0024] Optionally, the thickness of the second plating layer is 6-8 μm.

[0025] Optionally, the material of the contact piece body is beryllium bronze TBe2.

[0026] Optionally, the material of the contact ring body is aluminum bronze QAL10-3-1.5.

[0027] Optionally, the second plating layer is formed on the inner surface of the contact piece body by the ternary alloy plating technology. Of course, the entire contact piece body can also be plated with ternary alloy.

[0028] The ternary alloy plating technology is originally developed to meet the requirements of high-frequency connection and maximum conductivity in a wide frequency range. It is an alloy of copper, tin and zinc, with copper accounting for 55%, tin accounting for 25-30%, and zinc accounting for 15-20%. The ternary alloy has a similar appearance to stainless steel. Its resistivity is 1.7 μΩcm (RF-10 GHz), its conductivity is 59 (106S / m) (RF-10 GHz), and its contact resistance is less than 10 mΩ at 100 cN.

[0029] The ternary alloy plating technology is applied to the contact group protection structure of the switch machine for the first time. The surfaces of the contact piece body and the contact ring body of the switch machine are plated with ternary alloy by the ternary alloy plating technology. After testing, the contact group has been subjected to 1 million times of repeated experiments in a simulated field, and the results not only solve the problems of arc, oxidation, carbon deposition and powder loss in the plating nickel process and passivation process, but also keep the contact resistance unchanged at less than 10 mΩ in high-temperature, low-temperature and humid environments. The ternary alloy plating technology can also prevent surface oxidation and film formation, prevent scratching, and is not sensitive to bumps, and will not lose surface gloss during use.

[0030] The ternary alloy plating technology can meet the requirements of railway field use, greatly improve the service life of the contact group, and reduce the workload of daily maintenance of railway staff. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The figure is a schematic diagram of the application scenario of an embodiment of the present application.

[0032] Figure 2 The figure is a schematic diagram of the application scenario of an embodiment of the present application. Figure 1An enlarged view of the part encircled by the middle dotted line;

[0033] Figure 3 As Figure 1 An enlarged view of the part encircled by the middle dotted line.

[0034] Figure 4 As Figure 3 An enlarged view of the part encircled by the middle dotted line.

[0035] Explanation of reference signs:

[0036] 1, static contact piece; 101, contact piece body; 102, first plating layer;

[0037] 2, dynamic contact ring; 201, contact ring body; 202, second plating layer. DETAILED DESCRIPTION

[0038] The application will be further described in detail below with reference to the accompanying drawings.

[0039] In the description of the present application: unless otherwise specified, the terms "first", "second", etc. in the present application are intended to distinguish the objects referred to, and do not have a special meaning in the technical connotation aspect (for example, it should not be understood as an emphasis on importance or order, etc.). "Include", "contain", "have" and the like, also mean "not limited to" (some units, components, etc.).

[0040] In one embodiment, as Figures 1 to 4 shown, a contact group protection structure of a switch machine in the embodiment, wherein the static contact piece 1 comprises a contact piece body 101, and the surface of the contact piece body 101 is formed with a first plating layer 102 by plating ternary alloy technology; the dynamic contact ring 2 comprises a contact ring body 201, and the surface of the contact ring body 201 is formed with a second plating layer 202 by plating ternary alloy technology.

[0041] The thickness of the first plating layer 102 is 6-8 μm; the thickness of the second plating layer 202 is 6-8 μm.

[0042] The material of the contact piece body 101 is beryllium bronze TBe2.

[0043] The material of the contact ring body 201 is aluminum bronze QAL10-3-1.5.

[0044] In order to save costs, the second plating layer can be formed on the inner surface of the contact piece body by plating ternary alloy technology. Of course, the entire contact piece body can also be ternary plated.

[0045] The plating ternary alloy technology is mature and has clear specifications. The plating ternary alloy technology is originally produced to meet the requirements of high-frequency connection and maximum conductivity in a wide frequency range. The ternary alloy is an alloy of copper, tin and zinc, with copper accounting for 55%, tin accounting for 25-30%, and zinc accounting for 15-20%. The ternary alloy has a similar appearance to stainless steel. The resistivity of the ternary alloy is 1.7 μΩcm (RF-10 GHz), the conductivity is 59 (106S / m) (RF-10 GHz), and the contact resistance is less than 10 mΩ at 100 cN.

[0046] The plating ternary alloy technology is applied to the point group protection structure of the switch machine for the first time. The ternary alloy plating layer is formed on the surface of the point blade body and the point ring body by the plating ternary alloy technology, and a comparison experiment (test) is conducted with the existing nickel plating process and passivation process protection scheme, as shown in Tables 1-3.

[0047] Table 1 Test data of the embodiment

[0048]

[0049] As can be seen from Table 1, after the ternary alloy plating layer is formed on the surface of the point blade body 101 and the point ring body 201 by the plating ternary alloy technology, the contact resistance, wear amount and contact pressure do not change significantly after 50,000, 200,000 and 500,000 times of repeated experiments.

[0050] Through testing, the embodiment not only solves the problems of arc, oxidation, carbon deposition and powder falling caused by the nickel plating process and passivation process, but also has constant contact resistance, which is less than 10 mΩ, regardless of high temperature, low temperature or humid environment. In addition, the ternary alloy plating layer can prevent surface oxidation and film formation, prevent scratching, and is not sensitive to bumps, and will not lose surface gloss during use.

[0051] In addition, although the material of the point blade body 101 in the embodiment is beryllium bronze TBe2, and the material of the point ring body 201 is aluminum bronze QAL10-3-1.5. Since the first plating layer 102 and the second plating layer 202 play a substantial protection role, it can be expected that if the point blade body 101 and the point ring body 201 adopt other materials suitable for the plating ternary alloy technology, it is also feasible.

[0052] Table 2 Test data of the existing nickel plating process protection scheme

[0053]

[0054] From Table 2, according to the existing nickel plating process protection scheme, after 8000 times of current repeating experiments, the contact resistance has changed obviously, after 50000 times of current repeating experiments, the contact resistance of one group of moving and static contact points has approached the insulation state, and after more than 100000 times of current repeating experiments, the contact resistance of three groups of moving and static contact points has been in the insulation state.

[0055] Table 3 Test data of the existing passivation process protection scheme

[0056]

[0057] From Table 3, according to the existing passivation process protection scheme, after 500000 times of current repeating experiments, although the contact resistance does not change, the wear increases obviously, the surface loses gloss, and the contact pressure also decreases obviously, and the reliability is doubtful if it continues to run.

[0058] It should be understood that the application does not limit the structure of the contact piece body and the contact ring body, and even the expressions of "piece" and "ring" are only expressions for the most typical and conventional structure for the purpose of distinguishing the components of the static contact and the moving contact. As long as the body surface of the component of the switch machine contact group is plated with a ternary alloy to form a corresponding plating layer to achieve the protection structure of the switch machine contact group, it should be considered as the protection scope of the application.

Claims

1. A structure for protecting a set of points of a switch machine, comprising a set of fixed points and a set of movable points, wherein the contact units of the set of fixed points are point blades and the contact units of the set of movable points are point rings; characterized in that, The contact piece comprises a contact piece body, and a first plating layer is formed on the surface of the contact piece body by a ternary alloy plating technology; the contact ring comprises a contact ring body, and a second plating layer is formed on the surface of the contact ring body by a ternary alloy plating technology.

2. The switch machine contact set protection structure of claim 1, wherein, The thickness of the first plating layer is 6-8 μm.

3. The switch machine contact set protection structure of claim 1, wherein, The thickness of the second plating layer is 6-8 μm.

4. The switch machine contact set protection structure of claim 1, wherein, The material of the contact piece body is beryllium bronze TBe2.

5. The switch machine contact set protection structure of claim 1, wherein, The material of the contact ring body is aluminum bronze QAL10-3-1.

5.

6. The switch machine contact set protection structure of claim 1, wherein, The second plating layer is formed on the inner surface of the contact piece body by a ternary alloy plating technology.

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