Friction damper

Abstract

The essence of the invention is that the spring element (12), slidably mounted in the blind guide cylinder (9), is cylindrical in shape with a diameter significantly smaller than the inner diameter of the guide cylinder. Its bases rest on the surfaces of the support plate (11) and friction plate (10), which enclose the lumen of the guide cylinder (9) on both sides. The diameters of the support plate (11) and friction plate (10) correspond to the inner diameter of the guide cylinder (9). Furthermore, the support plate (11), spring element (12), and friction plate (10) are connected by a spring element preload screw (14) fitted with a nut (13), which passes through an axial through-hole.

Description

[0001] The subject of the invention is a friction damper, especially in the suspension system of a railway bogie.

[0002] The basic motion of a rail vehicle is in the direction defined by the track. However, this motion is disrupted by harmful movements caused by track irregularities and play between the wheel flanges and the rails, which causes loads on both wheel sets and entire bogies. Known solutions are based on reducing harmful loads through the use of two-stage suspension elements, among other things .

[0003] In current railway bogies, suspension systems are designed so that the bogie frame has bases in the suspension zone and is supported by springs on an accompanying saddle mounted on wheelset bearings. These bases are shaped to allow the saddle column to move up and down. Springs are located on both sides between the bogie frame and the lower saddle frame. The springs, in turn, have friction wedges located in the space between the bogie frame and these springs. Additionally, pads are used on the wedge surfaces to dampen lateral movements. However, under certain weather conditions or when individual parts are not properly aligned, the damping effect can be limited.

[0004] Other solutions involve using a system consisting of a friction plate and an insert positioned opposite the vertical axis of the saddle, unlike the solution above, where the friction wedges are positioned above the springs. This solution provides stiffness, but at the same time, horizontal forces, such as those generated when the truck is cornering, are not adequately damped.

[0005] The solution to this problem turned out to be the friction damper known from Polish patent application P.383055 (A). The friction damper is used in a system that includes a friction plate and an insert, and in this system, the friction damper replaces the friction plate. This system allows for the damping of horizontal forces because the friction damper , unlike the friction plate, has a spring element containing disc springs, which allow for the compression of the cylinder located in the friction damper by several millimeters. The friction damper is precompressed, ensuring the entire system has the appropriate stiffness. In the case of horizontal forces, the friction damper remains stiffened until a predetermined force limit is exceeded. Only after the force limit is exceeded does the cylinder located in the friction damper compress, reducing wear on the bogie components during cornering. When the friction pressure decreases, the disc springs relax, the cylinder in the friction damper expands, and it returns to its base setting. The disadvantage of disc springs is their service life, which is estimated at three to ten years depending on the intensity and conditions of use of the wagon / bogie.

[0006] Polish patent description PL207920(B) describes a suspension system for railway vehicles, particularly two-axle freight wagons, which consists of bases attached to the wagon chassis on both sides in the wheel set zones, supported by spring assemblies mounted on accompanying fifth wheels. The fifth wheel is mounted on the bearing housing (axle box) of the wheelset. Each base has a central space limited by the surfaces with which the fifth wheel columns interact. Friction wedges are used between the fifth wheel columns and the bases interacting with them on both sides. The friction wedges have built-in rollers, preferably one or two. In a two-roller friction wedge, the plane formed by the rollers is inclined to the horizontal by an angle of up to 35°, and the vertical surface has a pad made of a material with a low coefficient of friction less than 0.2, the outer surface of which is shaped like a section of a cylinder with a horizontal axis. The single-roller friction wedge has a vertical plane inclined towards the wedge drop by 3°, equipped with a pad made of a material with a low coefficient of friction less than 0.2, and a bumper on the inclined plane next to the roller on the lower side of the wedge. Springs with increased transverse stiffness were used. The stiffness change of the springs used so far was achieved by using a plate dividing the spring assemblies into parts, preferably two. To increase stiffness, the plates dividing adjacent springs supporting the base and wedge are interconnected, and corresponding dividing plates on one side of the wagon are connected to the dividing plates on the other side.

[0007] Polish patent description PL173525(B) describes a guide for a bogie wheel set equipped with coil springs as the main springs. The guide and drive forces are transferred from the wheel sets to the bogie solely by pairs of coil springs. The coil springs form spring packages, pre-tensioned by base plates placed at both ends and a pin permanently connected to one of the two base plates.

[0008] Polish patent application no. P. 340485 (A) describes a chassis for rail vehicles. This chassis has a torsionally resistant bogie frame, a crossbeam, and longitudinal girders. The axle bearing guides are mounted directly in the lower flange of the longitudinal girders, and the axle bearing guides are equipped with both sliding pressure elements with clearance, preferably two, and spring cups connected via links, which also rest on the axle bearings via spring assemblies. The pressure elements are pressed from both sides against the axle bearings by the spring cups.

[0009] The essence of the invention is that the spring element, slidably mounted in the blind guide cylinder, is cylindrical in shape with a diameter significantly smaller than the inner diameter of the guide cylinder. Its bases rest on the surfaces of the backing plate and friction plate, which enclose the lumen of the guide cylinder on both sides. The diameters of the backing plate and friction plate correspond to the inner diameter of the guide cylinder. Furthermore, the backing plate, spring element, and friction plate are connected by a spring element preload screw fitted with a nut, which passes through an axial through-hole. Preferably, the elastic element is at least one, and preferably two, polyurethane discs. In a preferred embodiment, the side surface of the guide cylinder is turned outwards at one end to form a flange and at the other end is curved inwards at a right angle. Preferably, the friction plate has a wear indicator for its friction surface in the form of an annular recess.

[0010] The main advantage of the solution according to the invention is the fact that the use of polyurethane discs, instead of those usually used in spring dampers, increases the service life of the device several times.

[0011] The solution according to the utility model is illustrated with drawings, in which Fig. 1 shows a friction damper in the suspension system of a railway bogie and Fig. 2 shows the construction of the friction damper.

[0012] The friction damper operates in a railway bogie suspension system comprising a frame 1 pivotally attached to the wagon chassis, supported on both sides by spring assemblies 2 mounted on saddles 4. Saddle 4 is mounted on the wheelset bearing body 3. There is a free space 6 between guides 5 and the saddle 4 cooperating with these guides, and the frame 1, while friction dampers are mounted in the guides 5. One guide 5 houses a friction insert 7 in the form of a mushroom, while the other, between saddle 3 and this guide 5, houses a cylindrical friction damper 8. The friction damper, slidably mounted in a blind guide cylinder 9, press-fitted in the guide 5 between the saddle 4 and the guide 5, has a cylindrical spring element 12 with a diameter significantly smaller than the inner diameter of the guide cylinder 9, located between the support plate 11 and the friction plate 10, adjoining them at their bases. The diameters of the support plate 11 and the friction plate 10 correspond to the inner diameter of the guide cylinder 9. The support plate 11, the spring element 12 and the friction plate 10 have an axially located through hole in which a screw 13 and a special nut 14 are placed, and this screw 13 constitutes a connector of all elements of the friction damper with the pre-tension of the spring element 12. The screw 13 is screwed in from the side of the support plate 11, and the nut 14 from the side of the friction plate 10 in such a way that after connection no element of the screw 13 and the special nut 14 extends beyond the outline of the friction damper 8. The polyurethane discs 12 located between the friction plate 11 and the support plate 10 are compressed during tightening of the screw 13 and the nut 14 so as to obtain the required initial tension of the friction damper 8. The compression of the polyurethane discs, both during tightening of the friction damper 8 and during its use, causes bulging of the side surface of the elastic element 12. The use of polyurethane discs with a diameter smaller than the internal diameter of the guide cylinder 9 leaves space for bulges formed during compression. The side surface of the cylinder 9 is bent outwards at one end to form a collar which rests on the edge of the hole in the guide 5. The support plate 11 is supported on the edges of the side surface of the guide cylinder 6, bent inwards at a right angle, at its other end.

[0013] The friction damper 8, in addition to damping frictions, maintains the perpendicular position of the wheelset relative to the track axis when driving on a straight track and at the same time enables radial adjustment of the wheelset when driving on curves. The bolt and nut can be replaced with a pin and cotter pin.

Claims

1. Friction damper, especially in a railway bogie suspension system, slidably mounted in a blind guide cylinder (9), press-fitted in a guide (5) between a saddle (4) and the guide (5), having at least one elastic element (12), characterized in that the elastic element (12) in the form of a cylinder with a diameter significantly smaller than the inner diameter of the guide cylinder (9) rests with its bases on the surface of the support plate (11) and the friction plate (10), closing the opening of the guide cylinder (9) on both sides, the diameters of which correspond to the inner diameter of the guide cylinder (9), and furthermore the support plate (11), the elastic element (12) and the friction plate (10) are connected to each other by a screw (13) passing through an axial through hole for the initial tension of the elastic element ( 12), provided with a nut (14).

2. The damper according to claim 1, characterized in that the elastic element (12) is at least one, and preferably two, polyurethane discs.

3. The damper according to claim 1, characterized in that the side surface of the guide cylinder (9) is turned outwards at one end to form a flange, and at the other end it is curved inwards at a right angle.

4. The damper according to claim 1, characterized in that the friction plate (10) has a wear indicator of its friction surface in the form of an annular recess (15).

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