Fire-resistant spring for primary suspensions of railway bogies

Abstract

Fire-resistant spring for primary suspensions of bogies on railways, comprising a core (1) which is connected to an elastic element (3) which in turn is connected to an outer piece (4), characterized in that it comprises a protective element (5) made of fire-resistant material which is connected at one end to the outer piece (4) and at the other end to the core (1), wherein a covering is defined which protects the elastic element (3).

Description

Technical area

[0001] The present invention relates to the suspension of railway carriages and proposes a spring acting as primary suspension on a bogie of said carriages, said spring comprising an element made of fireproof material covering the outer part thereof in order to protect, in the event of fire, an elastic element made of elastomeric material which is a component of the spring from the fire, and additionally to protect it from other external elements such as stones, sand, gravel, rain, ice or snow. State of the art

[0002] The suspension of a railway carriage bogie is typically implemented in two steps, with completely different solutions for each step. A primary suspension is placed between the wheel axles and the bogie frame, while another secondary suspension is placed between the aforementioned frame and the carriage body.

[0003] The tasks of the primary suspension are, in principle, to reduce the level of vibration acting on the bogie frame and the elements mounted on it and to ensure a homogeneous distribution of the load on the wheels.

[0004] One of the most commonly used solutions for primary suspension on railway bogies is the use of springs connecting the wheel axles to the bogie frame. These springs incorporate a rubber element that provides flexibility in all directions. Shock absorption is achieved through the elastomeric properties of the rubber, which serves as an elastic element in this type of spring. The use of springs such as those mentioned above for primary suspension on a railway bogie is a relatively inexpensive solution because it eliminates the need for hydraulic shock absorbers and additional, more expensive elements to ensure longitudinal and lateral guidance. A spring of this type is known from JP 2007-278 398 A.

[0005] However, the springs of this type known to date have the problem that the elastic element is not properly protected. In the event of a fire, the elastic element is quickly damaged by the fire, as it is mainly made of elastomer materials that can burn easily (usually rubber), which can cause severe damage to the spring.

[0006] Furthermore, the EN 45545-2 standard recently came into force, which stipulates that all railway carriage elements weighing more than 840 grams (including the aforementioned primary suspension springs) must incorporate a fire protection system. However, to date, no fire-resistant materials are known that can be used as elastic elements for springs while maintaining the required shock absorption properties.

[0007] Likewise, the elastic element of the aforementioned springs for primary suspension can also be damaged by external elements such as sand, stones, gravel, etc. Furthermore, weather conditions can affect the elastic element, as continuous direct contact with rain, ice, snow, or other atmospheric agents causes the wear of the aforementioned elastic element and, consequently, its deterioration. Object of the invention

[0008] All of these phenomena can damage the primary suspension springs and even cause them to break. Therefore, a spring for the primary suspension of a railway carriage is necessary, which includes means that protect the elastic element from these external, damaging phenomena.

[0009] The object is achieved by a fire-resistant spring according to patent claim 1. Further embodiments are the subject of the subclaims.

[0010] According to the invention, a spring is proposed which acts as a primary spring on a bogie of a railway carriage, said spring comprising a protective element which covers the outer part of the spring, thus preventing, in the event of a fire, the fire from burning the elastic element of the spring which is made of combustible elastomeric material.

[0011] Likewise, the protective element also protects the elastic element of the spring from other external elements that can wear out and damage said elastic element, such as stones, gravel or sand or weather influences such as rain, ice or snow.

[0012] The spring subject of the invention consists of a core having a truncated conical end to which the inner part of the elastic element of the spring is connected. The outer part of said elastic element is, in turn, attached to the inner side of an outer piece. Said outer piece has holes that allow the spring to be connected to the frame of the bogie in which it is used.

[0013] The other end of the core is tubular and has on the outer part an annular projection which acts as a stop when this end of the core is inserted into a piece that connects the axle of the wheels to the spring.

[0014] The upper end of the protective element is connected to the lower end of the outer piece, while the lower end of said protective element is supported and secured on the annular projection of the tubular end of the core, thus providing protection that prevents the elastic element from being damaged by external elements. Furthermore, said protective element is bellows-shaped and made of a material with a certain elasticity, allowing the spring to properly perform its functions as a shock absorber.

[0015] In this way, with the spring which is the subject of the invention, the required shock absorption conditions between the frame of the bogie and the axles of the wheels are met, said elastic element being protected from external elements by said protective element. Description of the characters Fig. Figure 1 shows a perspective view of a spring for acting as primary suspension of a bogie of a railway carriage, according to the subject invention. Fig. Figure 2 is a cross-sectional view of the spring in the upper figure. Fig. Figure 3 shows a perspective view of the spring without the protective element made of fireproof material. Fig. 4 shows a sectional view of the protective element made of fireproof material. Detailed description of the invention

[0016] The subject of the invention relates to a spring for the implementation of the primary suspension on bogies of railway carriages, said spring consisting of a core (1) having a tubular end provided at the outer part with an annular projection (2), while the other end of said core (1) has a truncated cone shape and is connected over its entire outer surface to the inner part of an elastic element (3), which in turn is connected at its outer part to the inner side of an outer piece (4).

[0017] The spring further comprises a protective element (5) which is designed like a bellows and which is connected at its upper end to the outer piece (4) and at its lower end to the annular projection (2) of the tubular end of the core (1).

[0018] The inner surface of the outer piece (4) has a conical shape, parallel to the frustoconical surface of the end of the core (1). Thus, the elastic element (3), made of an elastomeric material such as rubber or the like, can be bonded to said outer piece (4) and to said end of the core (1) by means of an adhesive vulcanization process.

[0019] Likewise, the elastic element (3) has integrated metallic inserts (6) which reinforce said elastic element (3), which are bonded to said elastic element (3) by vulcanization during the bonding process.

[0020] The upper end of the protective element (5) has a protrusion (7) extending toward its interior along its entire circumference. The lower end of the outer piece (4) has a gap (8) extending along its circumference, which gap (8) is complementary to the protrusion (7) of the protective element (5); so that, for the connection of the protective element (5) to the outer piece (4), the protrusion (7) is inserted inside the gap (8).

[0021] On the other hand, the protective element (5) has at its lower end an annular wing (9) facing inwards, which bears on the annular projection (2) of the tubular end of the core (1), said wing (9) being able to be fixed to said annular projection (2) by any type of fixing, such as by heat sealing or a mechanical connection by means of screws.

[0022] In this way, the protective element (5) is fixed at one end to the outer piece (4) and at the other end to the annular projection (2) of the core (1), in this way covering the elastic element (3) and protecting it from external elements.

[0023] The outer piece (4) is a tubular element, the upper end of which comprises a square wing outwards in which four through holes (10) are determined, which are intended for the mechanical connection, with screws or similar elements, of this outer piece (4) to the frame of the bogie.

[0024] On the other hand, the tubular end of the core (1) is inserted into a hole of a piece that connects the spring to the axle of the wheels, the annular projection (2) acting as a stop.

[0025] In this way, the spring connects the bogie frame to the wheel axles and performs the required tasks as a shock absorber between these two elements.

[0026] The protective element (5) is made of a fire-resistant material so that, in the event of a fire, said protective element (5) protects the elastic element (3), which is made of a highly flammable elastomeric material, from the fire. The material from which the protective element (5) is made is, as previously mentioned, fire-resistant and additionally has a certain elasticity that allows the spring to perform its primary suspension functions in an appropriate manner. For this purpose, a suitable material for forming the protective element (5) is an elastomeric thermopolymer, preferably ethylene propylene diene rubber, known as "EPDM."

[0027] Said protective element (5) also protects the elastic element (3) from stones, grit, sand, or small similar elements that may be projected from the rails and damage it. Likewise, said protective element (5) protects the elastic element (3) from weather conditions, as said elastic element (3) does not come into contact with atmospheric agents such as rain, snow, ice, or similar, and is therefore not affected by the continuous wear and tear these agents cause.

Claims

[1] Fireproof spring for primary suspensions of railway bogies, comprising a core (1) connected to an elastic element (3) which in turn is connected to an outer piece (4), characterized by in that it comprises a protective element (5) made of fire-resistant material, which is connected at one end to the outer piece (4) and at the other end to the core (1), defining a cover which protects the elastic element (3). [2] Fireproof spring for primary suspensions of bogies in railways according to claim 1, characterized by in that the connection between the protective element (5) and the outer piece (4) is carried out by a protrusion (7) arranged over the circumference of the upper end of said protective element (5) and a gap (8) which is complementary to the circumference of said outer piece (4). [3] Fireproof spring for primary suspensions of bogies in railways according to claim 1 or 2, characterized by that the protective element (5) has at its lower end an annular wing (9) facing inwards, which is supported and fastened on an annular projection (2) of the core (1). [4] Fireproof spring for primary suspensions of bogies in railways according to one of claims 1 to 3, characterized by that the protective element (5) consists of a fireproof material. [5] Fireproof spring for primary suspensions of bogies in railways according to claim 4, characterized by that the protective element (5) consists of an elastomeric thermopolymer. [6] Fireproof spring for primary suspensions of railway bogies according to claim 4 or 5, characterized by that the fire-resistant material of the protective element (5) is ethylene-propylene-diene rubber. [7] Fireproof spring for primary suspensions of bogies in railways according to one of claims 1 to 6, characterized by that the protective element (5) is designed like a bellows.

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