Views:7 Author:Site Editor Publish Time: 2019-06-24 Origin:Site
Bus window is an important part of bus. Whether its structure is reasonable or not not only directly affects passengers comfort, but also has a certain effect on bus manufacturing and maintenance, especially to prevent corrosion of side walls. In order to study the structure of the bus window in our country, we collected some information of bus windows.
1.Development and Structural Features of Unit-type Window
After the liberation, the newly-built 21 type and 22 type buses use single-glazed double-glass top-open-type window. This type of window has the following problems: (1) The window opening position is low, the wind blows directly onto the passengers. The passengers feel hot when they are in the leeward side in summer , while they can't stand the wind when they are in the windward side in the spring and autumn. (2) The glass is prone to condensation and frost in winter, which affects the sight. (3) It is difficult to wipe the glass between the double-glass windows. (4) Single-piece glass is poor in sound insulation and heat insulation. (5) Corrosion is serious at the corners of steel structures. (6) Since the window is opened on the top, the car’s cold resistance performance is degraded.
In 1990, Changchun Bus Factory led the development of China's first generation 25A type railway bus. The unit-type aluminum combination window appeared on the railway bus for the first time. In 1993, the design and development of the second generation unit-type aluminum combination window (KC3 series window) was completed.
Because there is a certain distance between the KC3 series window’s fixing glass and the window frame, the resistance during the driving process is relatively large. After it is improved, the KC3 plus modified series window appears, and the fixing glass and the window frame are kept in line, which provides protection for the speed of the bus.
For air-conditioned bus, the height of the opening window of KC3 plus modified series windows is higher. First, it increases the isolation of the outside of the bus; second, the ventilation can not be directly blown to the passengers; third, sealing is easier to guarantee. These advantages has been well received by passengers in the air-conditioned bus. However, due to the constraints of economic strength, at that time, a large amount of railway buses in China did not have air conditioners installed. On some railway operation lines, when the summer transportation capacity was tight, there were relatively more people in the train. The ventilation of the upper open windows was often impossible to meet the needs of passengers.
In response to this situation, a new type of lower-opening unit-type window has been developed. The lower-opening window has the following structural features: the lower opening window is designed to use the upper and lower window glass, and the body steel window size is the same as that of the original unified window, mainly composed by the outer frame, the upper fixed window, the lower living window, the window lock, the balance structure and the inner frame.
Because of the lower-opening window adopting various new technologies and techniques in the design, it has received the praise of the passengers with its excellent performance and quality. It can be said that the lower-opening window has a dominant position in the 25B type bus window market.
However, there are still some problems in the lower-opening window. The most important thing is that the window design and the process are not suitable. Because the gear and pinion transmission is adopted in the design, the assembly relationship of each component is complicated, and the engineering dimensions of the window are more strict. It requires a high level of technology. Once the window output is too large, the quality of the window will decline.
After 2000, the 25K internal pendulum series window began to be widely used in various K-type vehicles. It is divided into two types: movable and fixed. The window is built-in and the opening degree is about 35°. With interior frame, connected by block and steel structure, it has good sealing performance, thermal insulation and durability.
The 25K inner pendulum series window has the following structural features: (1) the fixed glass is below and the movable glass is upper. The upper glass of the movable window is turned inward by about 35%. (2) The mechanism that uses the connecting rod and the handle lock, which overcomes the problem of difficulty in disassembly. It can be disassembled by removing the connecting rod and the handle lock screw without disassembling the wall panel for maintenance. (3) The movable window’s opening lock and the triangular lock are separated to make passengers easy to open windows and let flight attendant easy to manage. (4) The window and the bus body are connected by a tension block, therefore, we can install and disassemble the window in the vehicle, which improves flexibility in the maintenance process. (5) The movable window is waterproofed by bus window adhesive.
With the development of high-speed railways in recent years, the window belt structure for high-speed trains has also appeared. The window belts are bonded with insulating glass and aluminum material, and connected with the steel structure by screws. The window belt and the original bus aluminum window have a qualitative leap in the structure, using a number of new technologies and techniques, combining the new techniques of tempering, interlayer, coating, net printing, etc. it make the window belts reach the most advanced level in the country on sound insulation, heat insulation, wind pressure resistance and various optical indicators. At the same time, the window glass is bonded with the window frame through high-performance structural adhesive, so that the window can withstand plus or minus 6000Pa. alternating stress, which ensures the needs of high-speed trains.
With the continuous advancement of railway bus technology, the railway bus windows have undergone rapid changes. The structure is from complex to simple, the technology is more comprehensive and advanced, it meets the increasingly high sealing requirements of railway buses. It plays an indispensable role in the development of railway technology in China.