RU2354568C2 - Monorail guide element - Google Patents

Abstract

FIELD: railway transport.

SUBSTANCE: invention relates to preset path monorail transport means. The proposed monorail guide element is made from sheet metal plate and features side surfaces intended for vehicle driving wheel rolling. Aforesaid side surfaces are furnished with replaceable coating representing a conveyor-belt-type reeled material. Lengthwise slots are arranged along the said guide element lower edges, each slot accommodating the reeled-material coat lower edge. The guide element top features a tubular bulge with a regular rhomb-section and is furnished with two parallel pressure plates arranged ar the 45°-angle. Note that the reeled material width exceeds the guide element height and that the pressure plates are furnished with lengthwise ledges arranged at their outer edges representing a half of cylindrical pipe.

EFFECT: high-accuracy preset path monorail with minimum weight per metre allowing dynamic characteristics required for rolling stock.

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Description

Technical field

The invention relates to the field of transport mechanisms with a given (fixed) trajectory and can serve as the basis for creating a new type of public transport.

State of the art

Having a relatively long history, monorail overpass transport systems still do not play a significant role in urban infrastructures. Surprisingly, the first devices that appeared about 100 years ago had approximately the same technical characteristics as quite modern transport systems operated in some cities of the world. For example, here we can cite US patent No. 1,049.782 containing a description of a high-speed crew with electric drive. The author even provided for special aerodynamic fairings - and all this in 1913.

In the future, mainly the external forms of vehicles and their parts (cases, windows, doors) change according to fashion trends in industrial design.

Apparently, the reason for the low prevalence of "monorails" is the high cost of track structures, which ultimately affects the cost of the ticket. Despite the apparent simplicity of the technical solutions in terms of rolling stock, the real requirements for the running track turned out to be very stringent in the literal and figurative sense. Any wide-span overpass is essentially a bridge tens of kilometers long, and bridges are the most complex of all building structures. If you try to simplify the task and reduce the span of the flyover, then due to the large number of supports it may well be more expensive than ground track structures of a traditional type. Designing a large-span flyover is a serious scientific and technical task, and existing solutions are on the verge of what is possible for modern construction technology. Experts consider the established order of things to be quite logical, in which the requirements of technical excellence and economy are mutually exclusive. Since there is no universal solution, the monorail remains unclaimed.

The analogue. As an analogue, the system described in US Pat. RF №2.167.403 (IPC 7 G01M 17/08, bull. 14/01) and now actually operating in Moscow as a "sightseeing".

This system is characterized by design features that allow us to talk about a new stage in the development of the "monorail" idea. First of all, the authors went to a noticeable lengthening of the axles of the double support wheels up to about 1 meter, which undoubtedly brings the monorail rolling stock closer to traditional vehicles. Secondly, to reduce the level of noise and vibration, instead of hard metal railway wheels, the authors used automobile wheels with rubber pneumatic chambers. Thirdly, instead of the traditional pairs of guide rollers spaced apart in height, the authors used mutually perpendicular pairs of rollers (wheels) located under the horizontal protrusions of the track. Thus, there is a rejection of the alluring, but practically difficult to implement concept of a single bearing plane and an attempt to go beyond the artificially set framework.

The authors practically did not change the design of the track, using a U-shaped box-shaped metal profile as the supporting beam (in the description of the RF patent No. 2.167.403, a closed box-tube of rectangular section appears). Due to the large size, the beams are prefabricated and are made of sheets of metal, known to be shorter than the span. This is how all modern metal bridges are arranged, and the presence of “joints” is considered by current designers as mandatory as the presence of asphalt on the road. However, the "joints" do not allow to lighten the beam, since the stiffness is determined solely by the thickness of the sheet. In a very detailed description of the invention there is information about the supporting beam, its linear mass is approximately 500 kg / m The concrete beam assumed at an early stage of the project would have a linear mass of about 1000 kg / m, but would be cheaper by about 30%. The authors definitely preferred aesthetics rather than profitability - the concrete overpass would have looked much worse. From a technical point of view, the gain is not so great. Here is a simple calculation that gives an idea of the true scale of “achievements”. A monorail train usually consists of 5-7 cars, each of which is designed to carry 15-20 passengers and has a length of about 5 meters (half the length of the cabin of a bus or trolley). The total length of the composition reaches 35-40 m, which accounts for about 15 tons of total weight, i.e. The “linear load” from the train is 400 kg / m - less than the weight of 1 m of the beam! If we compare the monorail beam with conventional bridges, then even its peculiar advantage will be revealed: after all, the bridge is obviously heavier than any transport in any quantity passing through it. It turns out that the main task of the bridge is to maintain its weight and not collapse from natural influences. Even the elegant-looking suspension bridges are very heavy, they just have most of the material located vertically and not horizontally (referring to the “pylons” - tall towers through which the tension cables pass). So, the Verazano bridge in New York has two "floors", and with a span of 1200 m, the total mass of its elements exceeds 50 thousand tons. Having occupied all 12 existing lanes of traffic delivered by heavy trucks, it will be possible to provide the bridge with a static load of about 20 thousand tons - less than half its own weight.

In addition to common “weaknesses” for such systems, the analogue has another serious drawback - this is a drive problem. Since the adhesion of the support (running) wheels to the smooth surface of the metal beam depends very much on the presence of water film in the summer and ice film in the winter, the speed had to be limited to 40 km / h (the figure was taken from the newspaper report about the official opening of the line). It is interesting to note here that the adhesion of railway wheels to rails is more reliable due to the enormous pressure arising in the zone of their direct contact (up to 1,000 atmospheres). The recommended pressure in the pneumatic chambers of cars does not exceed 2 atm, and in the chambers of trucks - 6 atm.

The mere fact of having a rubber tire does not guarantee its reliable grip on the road, and therefore all the long-term efforts of the developers are aimed at creating an “ideal” tread pattern. Alas, on the smooth surface of a metal beam, conventional methods of overcoming slippage are ineffective. Probably, precisely because of the problem with the drive, the operational speed was chosen to be very small, “excursion”. Finally, an increase in speed is not possible due to the presence of numerous curved sections of the track with small radii of curvature. The authors of Pat. RF №2.167.403 created a kind of flyover tram, but in all advertising brochures it is said about a new high-speed form of public transport.

Prototype. The design of the track according to the patent of the Russian Federation No. 2.264.316 (IPC B61B 13/04, EB 25/10, bull. No. 32/2005) is an attempt to create a system in which the role of the supporting element should be performed in a special way by a curved elastic steel strip. The author of this patent is far from alone in the search for a “minimal” construction of the roadway, similar ideas appear in another device in devices according to RF patents No. 2.204.640, No. 2.223.357, etc. The main thing here is the absence of joints, i.e. the principle of the integrity of the power element.

This very important difference brings the design closer to different types of suspension bridges, but the tape has an important advantage over the tension cable - it can provide lateral stability. The tendency of suspended structures to all kinds of vibrations is their main drawback, which is inherent in devices according to patents No. 2.204.640, 2.223.357. An increase in internal stresses leads only to an expansion of the spectrum of vibrations - a “one-dimensional” bearing element becomes a kind of guitar string. The advantages of the tape are demonstrated precisely with the help of a guitar, on which, together with ordinary strings of circular cross section, a tape is set close to the material properties. The ribbon “string” sounds much worse, because its vibrations decay very quickly and do not contain higher harmonics.

To accelerate and decelerate the rolling stock of the prototype, a concrete guide element is installed, mounted on top of a curved carrier tape and providing a high coefficient of adhesion of the rubberized side wheels pressed to concrete by hydraulic devices. Unfortunately, a convenient and simple design creates a problem in curved sections of the track. It is unacceptable to bend concrete blocks, so you will have to order special parts with different curvature radii. But even with an assortment of such blocks, it is very difficult to ensure the “smoothness” of the rolling surfaces for the side wheels. It is known that the curved sections of the railway track have the form of a hyperbola, and not at all circular arcs. When the car enters the circle, the centripetal force increases almost instantly - the wheels experience significant lateral loads, and passengers feel an unpleasant jolt. If the curved sections of the track are made with a smooth change in the radius of curvature, then the train moving at full speed “fits” into the turn almost imperceptibly for passengers. From this it is obvious that all longitudinal track elements must allow smooth bending. Longest metal products are easiest to bend to, and volumetric structures are much worse. It is very important that the true trajectory of the vehicle is determined not by the supporting (running), but by the side wheels. Therefore, some errors of installation of all the main elements, with the exception of the guide, are quite permissible. Alas, the metal guide element brings us back to the problem of clutch drive wheels. About 10-15 years ago, high expectations were placed on LED linear electric motors, but they were unable to provide sufficient effort with a reasonable mass of the moving part. Especially important is the “power reserve” during braking - the flyover system does not at all exclude the danger of a collision of vehicles.

A fundamentally new approach to the task is needed. For the drive, only the side surfaces are important, which should be provided with a special coating with a high coefficient of adhesion. You do not need to look for anything, because there is suitable material - this is a conveyor (conveyor) belt. If you manage to firmly fix it along the entire length of the metal guide element, you will get a "conveyor on the contrary." The main thing is that the guide element should have sufficient rigidity in the transverse direction and be able to withstand the compressive forces of hydraulics, but this is a completely solvable practical question.

So, the technical task of the present invention is the creation of a guide element of the track, which allows in practice to achieve an exact match between the true and calculated trajectories of the rolling stock, as well as to provide effective acceleration and braking in all weather and climatic conditions.

The technical result is a high-precision monorail running track with a minimum linear mass, providing the rolling stock with the necessary dynamic characteristics.

According to the first point, the technical result is achieved due to common features with the prototype, such as a guideway element of the running track, having vertical rolling surfaces on both sides for the side drive wheels of the vehicle, as well as distinctive essential features - the guide element is made of sheet metal and is provided on the sides interchangeable coating with a high coefficient of adhesion from a roll material such as a conveyor belt.

Clause 2 specifies the fastening of the roll material — longitudinal grooves are made along the lower edges of the guide element, in each of which the lower edge of the roll coating material is placed, while the guide element has a tubular thickening with a profile in the form of a regular rhombus and is equipped with two parallel clamping plates in the form of installed at an angle of 45 ° of the plates, while the width of the rolled material exceeds the height of the guide element, and the pads have longitudinal protrusions in the shape of half a cylindrical pipe.

The invention is illustrated in the drawing, in General terms, explaining the design idea. The drawing shows a cross section of a guide element of the running track.

The positions denote: 1 - a metal guide element, 2 - a removable cover made of a material such as a conveyor belt, 3 - a groove for accommodating the lower edge of the replaceable cover, 4 - a diamond-shaped thickening in the upper part of the guide element, 5 - clamping plates, 6 - half-cylindrical protrusions on the clamping lining, 7 - tightening bolts, 8 - curved in the form of an arch bearing elastic tape, 9 - fasteners, 10 - drive side wheels of the vehicle.

In order to simplify the drawing, the supporting wheels of the vehicle and the "driving shelves" are not shown for them, since the location of these elements is fully consistent with the prototype.

The possibility of longitudinal displacement of the guide element is an indispensable condition for the reliable operation of the entire system as a whole, since during acceleration and braking of the vehicle, the track experiences significant longitudinal loads. If the guide element 1 is rigidly attached to the carrier tape 8, then with a sharp braking of the vehicle, a catastrophe is possible - a “breakdown” of the carrier tape 8 from its mountings or a fall of the supports of the flyover. The “free” fastening of the guide element allows you to distribute the traction force on a long section of the running path, which has a significant total mass and quite noticeable equivalent longitudinal elasticity. The longitudinal elasticity of the guide element makes braking difficult, but this measure is forced because it protects the flyover from destruction.

Reliable clamping of the conveyor belt 2 is due to the fact that the forces acting on its edges are applied at an angle to the lateral surface of the guide element 1. Since the initial width of the roll exceeds the size of the space intended for installation of the tape, when the bolts 7 are tightened, the tape 2 is compressed, increases in thickness and while maintaining tight contact with the lateral surface of the guide element. “Rubber” fasteners are unacceptable for a rubber tape - stress concentrations occur around them and the tape breaks very quickly at the fastening points. Maximum strength is provided only by uniform crimping of the tape along the entire length of the travel path, which is the essence of the present invention. Adhesive bonding seems to be more expensive and less reliable, although it is not completely impossible. A simple solution to the problem is also possible by spraying a viscous substance such as tar or bitumen, but the friction coefficient noticeably increases in the "cruising" mode of movement.

It should be emphasized that the most important difference of a monorail vehicle is the controlled clutch of the side rollers with the running gear. The best option will be that the friction of the loose-pressed side rollers is minimal and the friction coefficient of the tightly pressed rollers is maximum.

Claims (1)

A guideway element made of sheet metal and having side surfaces for rolling drive wheels of the vehicle, characterized in that the side surfaces are provided with a removable coating of roll material such as a conveyor belt, while longitudinal grooves are made along the lower edges of the guide element, in each of of which the lower edge of the roll coating material is located, while the guide element has a tubular thickening with a profile in the form of a regular rhombus and is equipped with two pa allelic clamping plates as mounted at an angle of 45 ° the plates, the width of the web material exceeds the height of the guide element and the lining have on their outer longitudinal edges of the protrusions in the shape of half cylindrical tubes.