UA41731C2 - Slide bearing unit slide bearing unit - Google Patents

Abstract

A slide bearing unit has the pin of the shaft, a housing, a cylindrical ring in the body of which are provided windows of variable section, with anti-friction insertions placed in those. New in the invention is the fact that the outer and the inner surfaces of each insertion go out with respect to the outer and the inner surfaces of the ring by 0.02 - 0.04 of the thickness of the insertion, respectively, and the angle between the side walls of the insertion is equal to the angle between the side walls of the window, and is equal to the angle of self-retardation or smaller than that one.

Description

Description of the invention

The invention belongs to the field of mechanical engineering, in particular to high-speed sliding bearings, and can be used, for example, in roll cassettes of modern high-speed wire and small-grade rolling mills.

The well-known high-speed sliding bearing assembly used in the roll cassettes of rolling mills, developed by the German company FEB Schwermashinenbau-kombinat "Zrnst-Telman" (Germany) and supplied by the ZKET company to Ukraine, in particular to the Kryvyi Rih and Makiivka metallurgical plants (drawings

AB 150-02), made in the form of a sleeve, the inner surface of which is sprayed with anti-friction material and placed in the body of the cassette with tension. A shaft with a guaranteed gap is installed in the middle of the sleeve, which rotates at a frequency of 12,000-15,000 1/min. and has a high peripheral speed. To ensure the normal operation of the roller cassette, the oil of the company "Mobil" is used, which flows through the cassette and the oil cooler.

However, despite the improved lubrication system, failures occur in the operation of known roller cassettes, caused by overheating and the subsequent jamming of the working shaft in the bearing sleeve, which leads to the failure of parts that are expensive, such as the installation sleeve and shaft.

The high-temperature sliding bearing unit is also known (Association of the USSR Mo1233588 IPC:

Е16С17/02, 84 р.), containing a shaft trunnion, a body, a clip with rod inserts made of a material with a coefficient of linear expansion smaller than the coefficient of linear expansion of the clip material. Inserts are made in the form of modules, which include a rod made of anti-friction material and two coaxial bushings covering the rod. The inner sleeve is made with at least three axial grooves open to one of the ends of this sleeve, and of a material with a coefficient of linear expansion greater than that of the material of the outer sleeve and the anti-friction rod. In addition, the difference in the size of the thermal expansion of the inner fitting diameter of the outer sleeve and the outer fitting diameter of the anti-friction rod 29 is equal to the thermal expansion of twice the thickness of the wall of the inner sleeve on the side of its grooves. Gee)

The disadvantages of this bearing unit include the complexity of the design and the untechnological nature of its manufacture. It should be noted that when working with large radial loads due to the reduction of the bearing surface, high specific loads appear, in addition, there is a need to increase the thickness of the clip, which leads to an increase in the size of the structure as a whole. When making a return pair of friction, it is not possible to make stepped holes in the walls of the clip. Also, this design of the bearing unit imposes restrictions on the choice of anti-friction materials, which are determined by the discussed ratios of linear expansion coefficients. -

The closest in terms of technical essence to the claimed sliding bearing unit is the sliding support, "which is described in AS USSR Mo1079004 IPC R16S17/02 dated 09.09.81. This sliding support contains a shaft with a cylindrical collar mounted on it with anti-friction liners placed in it. At the same time, the inserts are installed in windows made in a bracket of variable cross-section, which increases from the periphery to the center.

In addition, the support is equipped with a device for pressing the inserts to the clip from the inner surface.

The disadvantage of the known technical solution is the impossibility of using it in high-speed structures with a high frequency of rotation of the shaft, because this invention has low reliability and a complex design. The low Z 70 reliability is due to the fact that the support is a reverse friction pair, that is, it rotates in the housing together with the shaft, while the dimensions of the rotating part increase, which increases the peripheral speed. It is known that for high speeds, dimensions and compactness play an important role, because speed and dimensions are directly dependent on each other. The device for pressing the inserts to the clip complicates the design of the device as a whole, increases its dimensions, disrupts the balancing of the shaft, and reduces reliability. With each replacement of the sliding support 79 in high-speed structures, additional balancing of the shaft is required, which is not always possible. - The task of the proposed technical solution is to ensure the operation of the sliding bearing unit in high-speed structures by increasing reliability and durability while simultaneously simplifying the structure. 4) 50 The task is achieved due to the fact that in the sliding bearing unit, which contains the journal of the shaft, the body, the cylindrical collar, in the body of which there are p windows of variable section with anti-friction inserts placed in them, according to the invention, the outer and inner surfaces of each of liners protrude from the outside outer and inner surfaces of the clip, respectively, by 0.02-0.04 of the thickness of the insert, and the angle between the side faces of the insert is equal to the angle between the side faces of the window and is equal to the angle of self-braking 59 or less than it.

GF) Comparative analysis with the prototype shows that the claimed device differs in shape, dimensions and 7 mutual placement of inserts. Cavities are formed between the liners protruding on the outer and inner surfaces of the clips, through which lubricant is supplied under pressure, creating a separation layer between the rotating elements at a high rotation frequency. This circumstance makes it possible to increase the reliability and durability of the device. In the known design, the bearing is installed directly on the shaft and constitutes a reverse friction pair. In the proposed design, the bearing can be fixed either in the housing or on the shaft, or with a guaranteed clearance on the shaft and in the housing. At the same time, the windows are made tapering, respectively, either from the periphery to the center, or from the center of the clip to its periphery. An essential feature related to the choice of the angle between the side faces of the liner and the side faces of the window and the equality of its angular 65 self-braking, allows you to exclude additional fastening of the liners, that is, to simplify the design of the sliding bearing unit, because the liners are reliably installed due to frictional forces. In the case of installing a bearing unit with a guaranteed gap in the housing and on the shaft, it is possible to reduce the relative speed due to the division of its value between the bearing and the housing and the bearing and the shaft.

Thus, the claimed device meets the "novelty" criterion of the invention. According to the set of essential distinctive features that provide a technical result, which consists in increasing the reliability and durability of the device, as well as simplifying its design, the claimed technical solution fully meets the "inventive level" criterion. In addition, the applied sliding bearing assembly successfully passed technical tests at the Kryvyi Rih Metallurgical Plant, thereby confirming its technical suitability. 70 The proposed technical solution is explained by the drawings presented in Fig. 1-3.

Figure 1 shows a longitudinal section of a sliding bearing.

Fig. 2 is a cross-section A-A of Fig. 1 in the case of installing the bearing in the housing.

Fig. 3 is a cross-section A-A of Fig. 1 in the case of installing the bearing on the shaft.

The sliding bearing unit contains a housing 1, a cage 2, an anti-friction ceramic insert C and a shaft 4. The cage has longitudinal windows 5 of variable cross-section, which narrows to the center of the cage when the bearing is installed in the housing, or from the center to the periphery when the bearing is installed on the shaft. The angle fr between the side faces of the windows is smaller than the self-braking angle. Inserts C are made, for example, of ceramics based on zirconium dioxide (2705) with corners equal to the corners of the windows. The radii of the outer surface 6 and the inner surface 7 of the liners are greater than the corresponding radii of the surfaces 8 and 9 of the clip by 0.02-0.04 of the thickness of the liner, due to which the liners protrude relative to the surface of the clip, while creating grooves 10 through which the lubricant enters.

Side and end surfaces of windows 5 clips are processed by milling, after which the side surfaces are polished. The side surfaces of the inserts C are installed in the windows 5 of the clamp from the side of its outer or inner surface with a certain force. Due to the angle of self-braking, inserts Z are reliably fixed in windows 5 clips. In the assembled form, the liners Z are ground in special devices that ensure accurate centering of the clamp relative to the axis of the clamp, first along the outer diameter b, and then along the inner diameter 7, or vice versa, depending on the direction of their pressing. When the bearing is installed with tension in the housing 1 or on the shaft 4 in i) inserts Z, compressive stresses are created, which favorably affect the material of the inserts, in particular when the inserts are made of (27гО5), increase the stability of its structural state, which in turn increases its wear resistance . In addition, the possibility of the formation of gaps between the liners C and the housing 1 is excluded when the bearing is heated to the operating temperature when it is installed in the housing 1 and helps to maintain the gap between the shaft 4 and the liners 3. When installing the bearing on the shaft 4, the possibility of the appearance of a gap between the shaft 4 is excluded o and inserts C and the gap between the body 1 and the inserts 3 is preserved. h-

The sliding bearing assembly works as follows (example when installing the bearing in the housing).

During the rotation of the shaft 4, the radial forces acting on the bearing are perceived by the liners 3, fixed in the clamp 2. Their weakening is excluded from the tension force between the liners and the housing, which ensures reliable centering of the shaft 4 during thermal expansion of the shaft 1, clamps 2, liners 3. In addition, the thermal expansion of the clip, due to the presence of a gap between it and the housing and the angle of the liner, increases the reliability of fixing the bearing Z in the housing 1. The grease that rolls through the grooves 10 between the liners, due to the "high frequency of rotation, tightens between the shaft and liners, creating an oil wedge and absorbs heat, which ensures the required temperature regime. - c The design of the sliding bearing assembly successfully passed the test at the metallurgical plant "Kryvorizhstal". The results of the tests confirmed the possibility of using the unit in the roll cassettes of high-speed rolling mills, at high shaft rotation frequencies (15,000 1/min). In addition, it was established that the bearing unit works sufficiently long and reliably. It is compact, technological in production, universal and autonomous, can be used both as a direct and as a reverse friction pair, can be installed to ensure a guaranteed gap with the body and with the shaft. Thus, the use of -3z of the proposed technical solution allows to reduce possible failures in the operation of rolling mills. -I at 50 -

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Claims (1)

The formula of the invention "- A sliding bearing assembly containing a shaft journal, a body, a cylindrical bracket, in the body of which windows of variable cross-section are made, narrowing from the periphery to the center or vice versa, with anti-friction inserts placed in them, which is distinguished by the fact that the outer and the inner surface of each of the inserts o protrudes relative to the outer and inner surfaces of the clip by 0.02 7 0.04 of the thickness of the insert, respectively, and "- the angle between the side faces of the insert is equal to the angle between the side faces of the window and is equal to or less than the angle of self-braking. "Official Bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2004, M 10, 15.10.2004. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. - with . and? sh» - -I o 50 - F) ime) 60 b5