JP4848331B2 - Method of joining rails for railway and cable terminals for energization - Google Patents

Description

  The present invention relates to a method for joining energizing cable terminals for electrically connecting rails for running electric vehicles such as cable cars and monorails in addition to trains and road rails.

Conventional technology

  Electric vehicles that run on railroad rails not only connect with remote areas to mass transport people and goods, but also greatly reduce transportation costs and transportation time, and play a role in promoting industrial development along the railroad. . Therefore, an efficient transportation system that ensures safety and speeds up is desired. Railroad rails used in such a situation are harsh use where repeated and complicated loads, impacts and vibrations are repeatedly applied from the rail top step where the wheels of the electric vehicle come into contact to the gauge corner and even the bottom. From the situation, there is a demand for a rail material that has improved bending fatigue strength in addition to wear resistance and fatigue damage resistance. Rail materials such as the development of tough rails with a fine pearlite structure in response to this requirement, the development of high-strength rails with a deeper hardening depth, and the development of rails with reduced fatigue damage on the rail tread surface New rails for railways have been developed to improve the service life and extend the service life. For railroad rails, fixed rails shipped from rail production factories are installed in welding plants and laying because of various demands such as simplification of rail maintenance, suppression of noise and vibration, improvement of riding comfort and safety at high speeds. Welding field technology to join and lengthen (long rail) on site is also being developed. More recently, a method for joining a current-carrying cable terminal connected to a railroad rail has been developed.

In order to run an electric vehicle in the railway business, the alternating current supplied from the power plant enters the railway substation via the transmission line and substation, and further passes through a current collector such as a trolley wire or pantograph. It is provided in an electric circuit that returns to a substation for electric railway through a rail after rotating and driving a motor of a vehicle. In addition, both the signal equipment and the circuit breaker equipment are provided with an electric circuit for flowing a signal current using a rail. In order to form these electric circuits, current-carrying cable terminals that are electrically connected are provided between the rails laid on the sleepers. The cable terminal for energization is also called a rail bond that connects the electric circuit for running the train and the signal circuit for safe driving of the train, and is composed of 90% pure copper and copper at both ends of the cable in which an annealed copper wire is twisted concentrically. A terminal made by processing one side of the gun metal made of 10% tin into a tubular shape is inserted, and both terminals of the current carrying cable terminal are attached to the side surface of the rail by bolting, or the rail and terminal are attached. Joined by brazing (soldering) at a low melting point that does not melt. Since bolting cuts a part of a rail, there exists a problem which causes material deterioration locally. Therefore, many soldering methods are generally employed. However, the soldering method also has a problem that the energizing cable terminal falls off the rail due to vibration accompanying the passing of the traveling vehicle. For the purpose of solving this problem, tools for securely bonding the energizing cable terminal to the rail are disclosed in, for example, Japanese Patent Laid-Open Nos. 5-82187, 10-128532, 11-176550, and 2004-2004. It is introduced in many patent gazettes such as 273403 gazette. Any of these patent publications is a jig for attaching an energizing cable terminal provided with a pressing mechanism for pressing the energizing cable terminal against the railway rail on a connection base fixed to the rail. However, even if the adhesiveness is improved by these tools, in a densely tracked section with many vehicles passing, vibrations and large repeated bending stresses of the rails affect the bonding part every time the vehicle passes, and the cable terminal for energization There was a problem of accelerating the dropout.
JP-A-5-82187 Japanese Patent Laid-Open No. 10-128532 Japanese Patent Laid-Open No. 2004-273403

  The present inventors have developed a bonding method that improves the adhesion between rail bonds and signal bonds, that is, railroad rails and current carrying cable terminals, so that the current carrying cable terminals do not fall off over a long period of time due to vibration of the electric vehicle. For this purpose, the current-carrying cable terminal mounting jig is improved, and further, the above-mentioned JP-A-5-82187, column 1, line 40, JP-A-10-128532, column 1, line 39, etc. As a result of various investigations on "alloy brazing, that is, lowering the melting point of railway rails and current carrying cable terminals than the melting point of railway rails and current carrying cable terminals" introduced in the section The performance is affected by the brazing alloy, that is, the adhesive alloy component or its composition, rather than the mounting jig for the current-carrying cable terminal, and the conventional tin-zinc-cadmium is used. Low melting point by joining with the adhesive alloy with silver (Ag) and ruthenium (Ru) in addition to a small amount of zinc or copper (Cu) if necessary instead of tin as the main component It has been found that the above-mentioned object of the present invention can be achieved by exhibiting operational effects such as good wettability, good workability, and ensuring the required adhesion and vibration resistance.

  The present invention is configured on the basis of the above-described knowledge, and the gist thereof is a joint between rails for rails laid in a long shape on sleepers laid on the roadbed at intervals in the traveling direction of the electric vehicle. Between the side joints of the rails for rails and the joint surfaces of the power cable terminals, silver: 0.2 to 3.9% by weight and ruthenium: 0.01 to 0.03 if necessary And a molten adhesive alloy material containing either zinc: 0.8 to 4.6% or copper: 0.8 to 1.0% and the balance being substantially made of tin. In this method, the molten adhesive alloy material is melted to bond the current-carrying cable terminals to the respective railroad rails, and the railroad rails and the current-carrying cable terminals are electrically connected between the railroad rails.

Since the above-described joining method of the present invention can be applied by a conventional joining method, it is not necessary to train a skilled person. In addition, the energizing cable terminal is strongly bonded to the side joint of the railroad rail. Its adhesive strength is 42 kg / mm ² or more. This adhesive strength is more than twice that of the conventional joining method, and stable adhesiveness can be obtained, and the electric circuit and signal circuit that the train travels can be stably maintained for a long period of time without peeling off due to the vibration of the traveling train. It has the advantage that it can be connected and the inspection of the adhesion status can be simplified.

Hereinafter, the joining method of the present invention for bonding a rail for rail and a cable terminal for energization will be described in detail.
Railroad rails are connected to each other via a joint between railroad rails that are laid in a long shape on sleepers that are laid on the roadbed at intervals in the traveling direction of an electric vehicle that supplies and drives power from a current collector. Between the side part of the joint from the body part to the leg part of the wire and the joint surface of the energizing cable terminal inserted into the terminal made of pure copper and gunmetal at both ends of the conductive cable twisted with the concentric copper wire In between, silver: 0.2 to 3.9% by weight and optionally ruthenium: 0.01 to 0.03%, further zinc: 0.8 to 4.6% or copper: 0.8 The molten adhesive alloy material containing any of ~ 1.0%, the balance being substantially made of tin, and formed into an arbitrary shape such as a ribbon shape (plate shape), a foil, a linear shape or a particle, is interposed, Connect rails for railways in a conductive manner. At this time, when an oxide film, dust, foreign matter, or the like adheres to the bonding surface, it is preferable to perform a mechanical or chemical cleaning treatment from the problem of deteriorating adhesion. In the present invention, tin as a main component of the melt-adhesive alloy has a low melting point, spreadability, good wettability to rails, excellent corrosion resistance and electrical conductivity, and is easily alloyed with various metals. In addition, it is a metal that has the properties required for brazing materials and is harmless to the human body and the environment. In particular, the low melting point and spreadability have the effect of further expanding the electrical conductivity by pushing out to a uniform thickness between the joint surface (part) of the railroad rail and the joint surface of the current carrying cable terminal at the time of press bonding described later. Play. Corrosion resistance has the effect of ensuring stable electrical conductivity for a long period of time in an environment exposed to rain and wind. On the other hand, since tin is a low melting point metal, when it is deposited at a high welding temperature, there is a problem that it boils and leaves many bubbles, and the adhesiveness is remarkably impaired. To solve this problem, a small amount of either zinc or copper is added in addition to silver. Tin is a metal having excellent electrical conductivity, rich ductility, and oxidation resistance, and is an effective component that generates an intermetallic compound with tin and imparts toughness to the molten adhesive alloy. This effect is that when the silver content in the tin alloy is less than 0.2%, the toughness of the melt-bonded alloy cannot be obtained. Moreover, since the excessive content of silver impairs the characteristics of tin, the upper limit was made 3.9%. Furthermore, ruthenium contained as necessary in the present invention is an effective component that refines the crystal grains of the molten adhesive alloy to improve adhesion and improve vibration resistance. The effect of grain refinement cannot be obtained. On the contrary, when the content exceeds 0.03%, the effect of refining crystal grains reaches the supersaturated region and tends to weaken the melt-bonded alloy. Therefore, the ruthenium content is limited to 0.1 to 0.03%.

  Furthermore, in the present invention, the molten adhesive alloy material contains a small amount of either zinc or copper. Since zinc has a higher ionization tendency than iron, it can prevent corrosion in the vicinity of railroad rail adhesion simply by contacting with iron, and also provides adhesion to a molten adhesive alloy with an alloy with tin. The effect cannot be obtained when the content of zinc is less than 0.8%, and when the content exceeds 4.5%, the content of tin tends to be reduced to deteriorate the spreadability and wettability. Accordingly, the content of zinc is limited to 0.8 to 4.6% as the content of corrosion resistance without impairing the action effect of tin. Copper is an effective component that imparts electrical conductivity and thermal conductivity and improves corrosion resistance against seawater. It is particularly effective in improving the corrosion resistance and electrical conductivity required for power cable terminals used in coastal railway areas. Is an essential ingredient. Such an effect of copper cannot be obtained with a small content of less than 0.8%. On the other hand, an excessive content exceeding 1.0% slightly increases the melting point of the melt-bonded alloy and deteriorates the workability. Show the trend. Therefore, in the present invention, the copper content is limited to 0.8 to 1.0%. In the present invention, the inclusion of zinc and copper in combination must be avoided from the problem that the melting point of the melt-bonded alloy is raised to deteriorate some characteristics and workability required for the joint. In addition, aluminum, iron, arsenic, and the like contained as inevitable components tend to deteriorate the corrosion resistance and electrical conductivity required for the adhesive metal, and therefore need to be reduced as much as possible.

The melt-bonded alloy material formed into an arbitrary shape such as a ribbon with the component structure as described above was interposed so as to be sandwiched between the side surface joint portion of the rail for rail and the joint surface of the power cable terminal. Then, while maintaining the periphery of the molten adhesive alloy in a vacuum, neutral or reducing atmosphere, heat in a heating furnace using a fuel gas flame such as blowpan or acetylene, or a heat source such as high frequency, arc, or electric resistance heat. While melting, press from both sides of the rail side rail joint and the current carrying cable terminal, bond the rail side rail joint and the current carrying cable terminal via the melted adhesive alloy, and conductively connect between the rail Connecting. Further, in order to spread the adhesive surface of the molten adhesive alloy uniformly and improve the adhesiveness, a flux (solvent) such as borax or boric acid may be applied to the adhesive surface in advance.
Since the adhesion between the rail for railway and the cable terminal for energization bonded by the joining method as described above is enhanced, the railroad track that forms a stable electric circuit without dropping off over a long period of vibration due to overcrowding Is obtained.

Next, examples of the bonding method of the present invention will be described.
A cable terminal for energization, in which a terminal formed by processing a tubular shape made of pure copper and gunmetal into a cable obtained by twisting a linear 0.45 mm annealed copper wire into a concentric circle on a 50 kg / m rail rail leg, has a thickness of 0.1 mm to After interposing a 0.2 mm melt-bonded alloy plate so as to be sandwiched, it was joined while heating in an argon gas atmosphere and pressing a rail terminal and a cable terminal for energization.
Table 1 shows the composition of the melt-bonded alloy at that time, the results of the determination of the wettability and workability during bonding, and the drop-off frequency of the current-carrying cable and terminal joined to the rail and the vibration test device. Results are shown.

From any of the above test results, the adhesion strength of the cable terminal for energization was 35 kg / mm ² or more in any of the test numbers, but the melting point (liquidus temperature) of the method of the present invention deviated from the component structure of the present invention Compared with the method, the workability was good and the wettability was good. In particular, the method of the present invention shows a high numerical value of the dropout frequency of the cable terminal for energization compared to the comparative method because of good wettability. This means that the current-carrying cable terminals joined by the method of the present invention have an excellent durability life.

  With the method of the present invention, the current-carrying cable terminal is joined to the joint surface of the railroad rail more strongly and without being corroded. It has many advantages and is expected to be used more and more in the railway business in the future.

Claims (1)

  Joining of rail rail side joints and current-carrying cable terminals through joints between rail rails laid in a long shape on sleepers laid on the road floor at intervals in the running direction of the electric vehicle A molten adhesive alloy material containing 3.7% by weight of silver and 0.9% of zinc and the balance substantially consisting of tin is interposed between the surface and the surface. A method for joining railway rails and current carrying cable terminals, comprising melting an adhesive alloy material, adhering current carrying cable terminals to respective railroad rails, and electrically connecting the railroad rails.