Shaft-bearing sliding unit

Abstract

FIELD: electrical machines.SUBSTANCE: shaft-bearing sliding units of electrical machines. The sliding shaft-bearing unit includes a rotor shaft, two composite radial-thrust conical bushings made of a hard aluminum alloy, ceramics or reinforced composite, designed to be placed in the base of the stator, and a lock washer with an adjusting screw secured to the end of the rotor shaft. Composite angular contact conical bushings are formed by a movable conical bushing with an outer cone, which is mounted on the rotor shaft, and a fixed conical bushing with an inner cone, designed with the possibility of placement in bearing seats of the stator base. In this case, the angle of the cone of the bushings relative to the axis of rotation is made within the range of 30–60°. The friction surfaces are coated with a plastic or solid lubricant coating.EFFECT: possibility to regulate the working clearance between friction surfaces, improve the manufacturing efficiency of the shaft-bearing unit, and facilitate monitoring the condition of friction surfaces with applied lubricant.2 cl, 3 dwg

Description

[0001] The proposed invention relates to shaft-bearing sliding units of electrical machines and can be used in the aviation industry, power generation systems, ventilation, air conditioning, compressor and pumping stations.

[0002] A shaft-bearing unit is known with a shaft made of steel or titanium alloys, having sliding zones, and two sliding support bushings made in the form of cylinders made of metal alloys with a lubricant (liquid, solid or plastic) applied to the friction surfaces, or a combination of 2-3 types of lubricants; in this case, the support bushings perform the function of radial bearings, taking perpendicular loads on the shaft; to ensure longitudinal loads on the shaft, additional flanged plain or rolling bearings are required, performing the function of thrust bearings (GOST ISO 4378-1-2001).

[0003] During operation of such a shaft-bearing assembly, the friction surfaces gradually wear out, leading to an increase in the clearance between the friction surfaces. Therefore, the main drawback of this design is the lack of adjustment of the operating clearance between the friction surfaces between the shaft and the bearing bushings. Furthermore, the use of solid and plastic lubricants complicates quality control and the technology for applying them to the friction surfaces of the bearing bushings.

[0004] The technical results of the proposed invention are the creation of the possibility of regulating the working clearance between friction surfaces, increasing the manufacturability of the shaft-bearing unit and facilitating the monitoring of the condition of friction surfaces with applied lubricant.

[0005] The specified technical result is achieved by a sliding shaft-bearing unit, including a rotor shaft, configured to be installed in a rotor flange, two composite radial-thrust conical bushings made of a hard aluminum alloy, ceramics or reinforced composite, configured to be located in the stator base, and a lock washer with an adjusting screw secured to the end of the rotor shaft, the composite radial-thrust conical bushings are formed by a movable conical bushing with an outer cone, which is mounted on the rotor shaft, and a fixed conical bushing with an inner cone, configured to be placed in bearing seats of the stator base, wherein the cone angle of the bushings relative to the axis of rotation is made within 30-60°, and a plastic or solid lubricant coating is applied to the friction surfaces.

[0006] In addition, the adjusting screw and the lock washer are designed to adjust the working clearance between the friction surfaces at the end of the shaft of the electric machine.

[0007] This invention is illustrated by graphic materials, where Fig. 1 shows an example of an electric motor with an external rotor and a radial-thrust shaft-bearing sliding unit in section, Fig. 2 is a top view of the device, Fig. 3 is an electric motor with an external rotor and a radial-thrust shaft-bearing sliding unit in section in axonometric view.

[0008] The proposed shaft-bearing unit with radial-thrust sliding bushings (Fig. 1 and 3) consists of a shaft 1 of a rotor 8 of an electric motor made of a steel or titanium alloy, two composite radial-thrust conical bushings 2-3 and 3-4 made of a hard aluminum alloy (D16, AMg5, AMg6 or B95), ceramics or reinforced composite material, a lock washer 5 and a lock screw 6, which is also designed to adjust the working clearance between the friction surfaces of the composite bushings 2-3 and 3-4. Each composite radial-thrust conical bushing 2-3 and 3-4 consists of two parts - a movable part with an outer cone 2 and 4, which are mounted on the shaft 1, and a fixed conical bushing with an inner cone 3, placed in the bearing seats of the base of the stator 7 of the electric motor. Plastic or solid lubricants are applied to the friction surfaces of the composite radial-thrust conical bushings 2-3 and 3-4, forming an antifriction layer A (see Fig.1) on friction surfaces, for example, antifriction solid lubricant polymer coating with the addition of molybdenum disulfide or graphite.

[0009] The production of composite bushings 2, 3, 4 from a hard aluminum alloy, ceramics or reinforced composite material allows for a significant reduction in the weight of the shaft-bearing sliding unit compared to bushings made of steel, brass, bronze and bronze-graphite alloys, as well as compared to rolling bearings with a cage made of steel alloys.

[0010] Composite radial-thrust tapered bushings 2-3 and 3-4 are designed to function as a thrust-radial bearing by tilting the friction surfaces relative to the axis of rotation at a selected angle in the range of 30-60°, as well as centering shaft 1 relative to the stator assembly. The cone angle of the friction surfaces of composite radial-thrust tapered sliding bushings 2, 3, 4 relative to the axis of rotation is calculated taking into account the necessary ratio between the radial and longitudinal loads on shaft 1 and is in the range of 30-60°. If it is necessary to ensure equal longitudinal and transverse loads on rotor shaft 1, an inclination angle of 45° of the friction surfaces is optimal. If the magnitude of radial (transverse) loads on the rotor shaft 1 prevails over longitudinal loads, the optimal angle of inclination is selected in the range of 30-45°, and if longitudinal loads on the shaft prevail over radial loads, it is 45-60°.

[0011] Adjusting screw 6 is installed in the threaded hole in the end of shaft 1 to fix the axial position of rotor 8 relative to stator 7 of the electric machine. Lock washer 5 with adjusting screw 6 also ensures the required adjustment of the working clearance between the friction surfaces of composite sleeves 2-4, as well as fixing bushings 2-4 and shaft 1 after the clearance has been adjusted. The value of the working clearance is set taking into account the characteristics and operating modes of the electric machine. To decrease the clearance between the friction surfaces of composite sliding bushings 2-4, it is necessary to turn adjusting screw 6 clockwise, and to increase the clearance, turn screw 6 counterclockwise. After completing the clearance adjustment, adjusting screw 6 must be protected from loosening with a special varnish or thread locking agent, also ensuring that the position of shaft 1 of rotor 8 is fixed relative to stator 7 of the electric machine.Adjusting screw 6 is secured with varnish or thread locking compound. Radial and axial clearances are achieved by tooling and grinding the friction surfaces during electric motor assembly.

[0012] The device operates as follows.

[0013] The proposed shaft-bearing sliding unit (Fig.1-3) is used primarily in electric motors for unmanned aircraft systems and ventilation systems.

[0014] Shaft 1 rotates in two composite radial thrust sliding bushings 2-3 and 3-4, in which the fixed parts 3 are pressed into the base of the stator 7, and the movable parts 2 and 4 are secured on shaft 1 of rotor 8. Axial movement is limited by the flange of shaft 1 and lock washer 5, secured to the end of shaft 1 of rotor 8 by lock screw 6.

[0015] Thus, the proposed invention provides for the adjustment of the working clearance between the sliding surfaces, reduces the cost of manufacturing bushings, facilitating the application of lubricants and improving the quality of monitoring the condition of friction surfaces to increase the service life and reliability of the electric machine.

Claims

1. A sliding shaft-bearing unit including a rotor shaft configured to be installed in a rotor flange, two composite radial-thrust conical bushings made of a hard aluminum alloy, ceramics or reinforced composite, configured to be placed in the stator base, and a lock washer with an adjusting screw secured to the end of the rotor shaft, the composite radial-thrust conical bushings being formed by a movable conical bushing with an outer cone, which is mounted on the rotor shaft, and a fixed conical bushing with an inner cone, configured to be placed in bearing seats of the stator base, wherein the cone angle of the bushings relative to the axis of rotation is within 30-60°, and a plastic or solid lubricant coating is applied to the friction surfaces.

2. A sliding shaft-bearing unit according to claim 1, in which the adjusting screw with a lock washer is designed with the possibility of adjusting the working clearance between the friction surfaces at the end of the shaft of the electric machine.

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