Mga gulong ng sasakyan at ang kanilang suot
Ang wheel set ay isa sa mga mahalagang bahagi sa running gear ng mga metrong sasakyan. Dahil nagdadala ito ng malalaking static at dynamic na load, ang bawat bahagi ay dapat may sapat na lakas at Salik ng kaligtasan. Sa mabilis na pag-unlad ng teknolohiya ng wheel rail at ang makatwirang pagtutugma ng tigas ng wheel rail, malawakang ginagamit ang integral rolled steel wheels sa mga sasakyang subway. Ang integral rolling steel wheel ay nag-aalis ng tradisyonal na inlayable na gulong, na isinama sa wheel center at may mataas na lakas, mataas na tigas, at mahusay na pagsusuot at paglaban sa init. Gayunpaman, dahil sa kakulangan ng gulong, ang diameter ng gulong ay umabot sa limitasyon, at ang sentro ng gulong ay dapat mapalitan sa kabuuan. Ang sasakyan ay ginagabayan ng mga set ng gulong kapag dumadaan sa mga kurba. Kung mas maraming kurba, mas maliit ang radius. Ang mas maraming pakikipag-ugnay sa mga rim ng gulong ng mga set ng gulong sa mga riles ng bakal, mas malala ang pagkasira ng mga rim ng gulong. Ang disenyo ng mga linya ng subway ay pinipigilan ng mga salik tulad ng urban terrain, geology, underground pipelines, pamamahagi ng gusali, mga kondisyon ng konstruksiyon, at maginhawang transportasyon, na nagreresulta sa maraming maliliit na radius curve.
Ang mga regulasyon para sa pangkalahatang pinagsamang mga gulong na bakal na ginagamit sa mga sasakyang subway ay nagsasaad na ang bagong diameter ng gulong ay 840mm, na may limitasyong 770mm. Bilang karagdagan, ang mga sasakyan ng kapangyarihan ng paghahatid ng AC ay may mahigpit na mga regulasyon sa pagkakaiba ng diameter ng bawat gulong, na may pagkakaiba sa pagitan ng mga diameter ng dalawang coaxial na gulong na hindi hihigit sa 1mm, ang pagkakaiba ng diameter ng bawat gulong ng parehong power car bogie na hindi hihigit sa 2mm, ang diameter pagkakaiba ng bawat gulong ng parehong kotse na hindi hihigit sa 4mm, at ang kapal ng flange ng gulong ay 32-26mm. Ang kalidad ng pagtapak nito ay may malaking kahalagahan sa kinis at kaligtasan ng operasyon. Kung ang pagtapak ng isang pares ng mga gulong ay nabutas o ang flange ng gulong ay umabot sa limitasyon, ang isang non-falling wheel lathe ay dapat gamitin upang iproseso ang mga gulong ng isang kotse, na may unilateral cutting na halaga na 25mm bawat oras. Batay sa halaga ng pagputol na ito, maaaring mahinuha na ang bagong gulong Z ay kailangang i-machine nang tatlong beses upang maabot ang limitasyon. Kapag naabot na ang limitasyon, dapat i-disassemble ang bogie at ipadala ang wheel set sa pabrika para palitan ang wheel cake. Hindi na masasabi na malaking halaga ng lakas-tao at gastusin ang nagastos. Para sa isang rolling stock depot, ang pagtiyak sa pagpapanatili ng sasakyan at oras ng paghinto ay ang susi sa normal na operasyon. Gayunpaman, ang labis na distansya sa pagkukumpuni ay hindi maiiwasang humahantong sa matagal na pagpapanatili at oras ng paghinto, pagbawas sa paggamit ng sasakyan, at higpit ng paggamit ng sasakyan. Kasabay nito, ito rin ay nagpapahirap sa paglilipat ng mga ekstrang bahagi para sa mga set ng gulong. Ang isang 6-kotse na subway na sasakyan ay may 24 na pares ng mga gulong, na nangangailangan ng higit pang mga wheel set na ekstrang bahagi para palitan. Kapag ang supply ng mga ekstrang bahagi ay hindi magagamit, ang sasakyan ay nasa kalagayang naghihintay para sa pagkukumpuni, hindi makapag-online nang normal, at magdudulot din ito ng tensyon sa paggamit ng mga track ng garahe. Ang downtime ng maintenance at turnover ng mga ekstrang bahagi ay mahalaga para sa depot. Napapanahon ang pagpapanatili, at ang mga sirang sasakyan ay kailangang ilabas sa bodega ayon sa plano. Sa ganitong paraan lamang magiging maayos at makokontrol ang kaligtasan, kalidad, site, at operasyon.
At present, the repair of DF4D, DF11 and DF11G locomotives in the Motive power depot often encounters that the spare parts for integral rolled steel wheels cannot keep up with the limit of wheel diameter, and even the manufacturers cannot supply them. Some subway operating companies have already encountered issues with wheel flange processing on lines with small curve radii. At the same time, the track and wheel are a pair of friction pairs, and reducing the wear of the wheel flange also requires considering the wear of the steel rail. If the steel rail is worn to the limit and replaced, it is also a significant investment in economy. In order to solve the problem of wheel flange and rail wear and ensure the service life of the wheel set for one repair period (about 12 years), it is necessary to install a wheel flange lubrication system in subway vehicles to reduce wheel flange wear.
Working principle of wheel flange lubrication system
The wheel flange lubrication system is divided into two types: single line and double line. The oil and gas mixture shown in Figure 1 directly enters the nozzle, which is called a single line. As shown in Figure 2, each nozzle needs to be connected to a separate oil and gas pipe, and a connection block is required in front of each nozzle, which is referred to as a dual line.
Figure 1 Single line wheel flange lubrication system
Figure 2 Dual Line Lubrication System
The dual line lubrication system is composed of a controller, an electric control valve, a grease tank, and a nozzle. The compressed air through the electric control valve is output in two ways, and the quantitative grease is pressed into the nozzle through the grease tank and nozzle inlet; Another way of compressed air enters the air inlet of the nozzle, atomizing the grease inside the nozzle and spraying it out. This type of lubrication system is widely used on Locomotive, such as HB device. This system uses locomotive air source to spray JH type special graphite grease in grease storage tank to the root of wheel flange intermittently through the nozzle, so as to reduce harmful wear between vehicle wheel flange and rail. The electronic controller is a key component for achieving automatic control of the system. The HB-2 model can set the distance between two fuel injections on the electronic controller, with each injection time of 2 seconds. In 2000, the Institute of Metallurgy of the Chinese Academy of Railway Sciences designed and developed a device that can control the wheel rail lubrication system to achieve automatic timed grease spraying control (the new HB-3 wheel rail lubrication device). This electronic controller implements the timed grease spraying mode of the system, utilizing the line section information provided by the locomotive's on-board ground data to develop corresponding software. It can be used in conjunction with curve sensors, and can achieve multiple lubrication forms, with intelligent lubrication function for curves. It can correctly identify line sections (straight, left, and right curves), and adopt different grease spraying control modes for straight and curve sections. Through the above measures, locomotive and vehicle can maintain a more reasonable lubrication state when passing through curves, further reducing wheel flange wear, and also reducing rail wear in curve sections. In addition, a water separation filter has been installed on the basis of the HB-2 model, reducing the failure rate of the nozzle and electric air valve; A new type of grease tank has been designed to improve installation reliability.
The single line wheel flange lubrication system shown in Figure 1 consists of a pneumatic pump, an air solenoid valve, an oil air distributor, a nozzle, and a control device. The pneumatic plunger pump uses the compressed air of the vehicle to inject lubricant into the oil gas mixing block. The lubricant and compressed air are mixed in the oil gas mixing block, and with the help of compressed air, they are distributed through the distributor and sent to the nozzle, which is directly sprayed onto the wheel flange (Figure 3).
Figure 3 Lubricant sprayed from the nozzle onto the wheel flange
As the speed of the vehicle increases, the centrifugal force generated around the wheel rims thickens the lubricating film, and the lubricant is easily thrown out under the centrifugal force. Experiments have shown that when the particle diameter is greater than 0.4mm, centrifugal force will cause the lubricant to splash. If the lubrication system has a high injection speed and a small particle diameter, the lubricant will not splash. Avoiding lubricant splashing not only reduces lubricant consumption, but also avoids lubricant pollution to vehicles and the route. The test conducted by the Deutsche Bundesbahn Bureau shows that when the diameter of the lubricant particles sprayed is less than 0.4 mm and the vehicle speed reaches 300 km/h, no excess lubricant is found on the rail after 40 consecutive injections. In addition, the surface pressure between the wheels and rails is extremely high, and the pressure resistance of the lubricant must be good. The lubricant must contain a high proportion of solid extreme pressure additives?, Such as fine graphite. In a single line lubrication system, the intermediate pipeline between the pump and nozzle contains approximately 10% lubricant and 90% compressed air, which allows compressed air to form a fine oil film layer on the lubricant during the spraying process. Under the action of compressed air, a lubricant with a high proportion of pressure resistant solid particles is added and sprayed onto the wheel flange at a high speed of 150-200m/s to ensure that the sprayed lubricant can break through the air flow and driving wind around the wheels and finely cover the wheel flange of the vehicle at high speed. The thickness of the oil film sprayed onto the wheel flange reaches 0.001mm, with a width of 10-15mm. A lubricant amount of 10-30mm3 is sprayed onto the wheel flange in Z fine particles within a few seconds. If the pneumatic pump adopts a quantitative pump, the longer the injection time, the finer the particles, but the compressed air capacity is limited. Therefore, the injection is not continuous, but once every other period of time, lasting for 6-10 seconds. The spraying interval of lubricants can depend on time or distance traveled; When the vehicle is in a bend, a bend sensor or on-board ground data system can be used to provide the position of the bend. At this time, the spray dose on the outer edge of the curve should be appropriately increased. Stop working when the vehicle's speed drops below a certain value, ensuring that the lubrication system does not work when the vehicle is parked or parked.
With the improvement of automation, the controller of the lubrication system has been based on microprocessors, optimizing the lubrication cycle Z based on distance, speed, curve, or any combination. By programming, lubrication can be avoided during sandblasting, braking, and low-speed operation. When the locomotive is in a bend, the curve sensor can sense and increase the lubrication of the wheels on the outside of the bend.
China's railway system has developed a wheel rail solid lubrication device, which consists of a wheel rail solid lubrication rod and a lubricating rod bearing and fixing mechanism. It has the characteristics of low operating cost, reducing locomotive flange wear, improving the adhesion stability of locomotive driving wheel tread, convenient installation, use and maintenance, and low pollution, and can meet the requirements of Locomotive operation. Jinan West Motive power depot uses the gravity type dry flange lubrication device on NDS locomotives. After six years of operation, it shows that the gravity type solid (dry) flange lubrication device is simple and reliable in design, free of maintenance, easy to manage, and low in cost. The dry lubricant has strong adhesion, easy film formation, extreme pressure resistance, and good long-term effect. The wear reduction effect is very prominent. The wear rate of the wheel flange is reduced from 0.37mm/10000km to 0.18mm/10000km.
Effect of using a rim lubrication system
The wheel flange lubrication system is compact and simple, with high economic benefits.
(1) Rim wear is greatly reduced, greatly extending the service life of wheels and tracks. After investigation, the Technical Center of the Deutsche Bundesbahn Bureau found that in practical application, on a line with many curves, the distance that locomotive wheels could travel before the next grinding cycle was only 10000 to 20000 km, but after the installation and use of wheel flange lubrication equipment, the distance could be increased to 100000 to 200000 km under the same line conditions. At present, after using high-performance wheel flange lubrication equipment, the distance traveled by the locomotive has reached 400000 km or even more before the next grinding cycle.
(2) Reduced noise, especially on bends and turnouts. The noise generated by vehicles during driving can reach 100dB in the past, and even higher when driving in curves and tunnels; And when the subway passes through cities or residential areas, the noise directly affects the comfort of passengers and disturbs the residents along the line. The use of high-performance wheel flange lubrication system not only reduces wear between wheels and tracks, but also reduces noise. The measurement results in Budapest, Hungary show that the use of a high-performance wheel flange lubrication system reduces the noise level by 30dB, reduces the squeaking and piercing noise of the original vehicle during operation, and also avoids sparks rubbing between the wheels and the track during cornering.
(3) Reduce operational resistance and reduce the probability of train derailment. Excessive friction between the wheel flange and rail angle can easily cause the train wheels to climb off the track. After using flange lubrication, the roughness of the rail angle is reduced and the frictional resistance is reduced.
(4) The lubricants used in wheel flange lubrication systems nowadays are generally biodegradable synthetic oils, which are mobile lipids. In addition, adding a high proportion of solid particle components, such as graphite disulfide aluminum powder, to the synthetic oil can significantly improve the wear resistance of the wheel flange without increasing environmental pollution.
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2023-07-18