RU2075055C1 - Device for evaluating lubricating properties of oils - Google Patents

Abstract

FIELD: mechanical engineering; testing facilities. SUBSTANCE: device has housing, bearing friction unit installed on rotating shaft inside housing, and four-ball friction unit mounted on end of shaft. Radial blades are secured on end of shaft in zone of four-ball friction unit. EFFECT: improved quality of checking. 2 cl, 1 dwg

Description

 The invention relates to instrumentation, in particular to devices for determining the properties of transmission and motor oils.

 One of the main indicators that determine the performance of an oil is its lubricity. The lubricity of an oil is primarily influenced by the presence of an anti-wear additive in the oil, as well as abrasive solids. During the operation of the oil in the aggregates, its lubricating ability deteriorates: the additive is activated, and abrasive mechanical impurities accumulate. Therefore, in order to determine the suitability of the oil for further use, it is necessary to determine the degree of change in these indicators.

 A device for the rapid assessment of the lubricity of oils used in units of agricultural tractors [1] comprising a housing, a friction bearing assembly mounted inside the housing on a rotating shaft, and a four-ball friction assembly mounted on the shaft end.

 The principle of operation of the known device is that the tested oil is simultaneously tested in four-ball and bearing friction units, the thickness of the lubricant layer in which depends on the presence of antiwear additives and abrasive mechanical impurities in the oil. For example, with a decrease in the concentration of antiwear additives in the oil, the thickness of the lubricant layer in the four-ball friction unit decreases. And in the friction bearing unit, the thickness of the lubricant layer decreases with increasing content of abrasive solids. By measuring the thickness of the lubricating layer in these nodes under the appropriate friction conditions and comparing with the reference values, judge the lubricity of the oil.

 Practical experience of using this device showed that the abrasive mechanical impurities contained in the test oil, falling into the four-ball friction unit, have a noticeable effect on the thickness of the lubricating layer in it, which distorts the result of the additive and, accordingly, reduces the accuracy of evaluating the lubricity of the oil.

 The objective of the invention is to limit the ingress of abrasive solids contained in the test oil into the four-ball friction unit.

 The problem is solved as follows.

 The proposed device, as well as the known one, comprises a housing, a bearing, a friction assembly installed inside the housing on a rotating shaft, and a four-ball friction assembly mounted on the shaft end.

 In contrast to the known, in the proposed device in the area of the four-ball friction unit, radial blades are fixed on the shaft end.

 Thanks to these blades, the abrasive mechanical impurities contained in the oil are discarded from the four-ball friction unit as a result of the rotational movement of the oil under the action of centrifugal forces.

 Thus, the task is solved, which provides the following technical result, reducing the influence of abrasive mechanical impurities on the thickness of the lubricating layer in the four-ball friction unit and, accordingly, improving the accuracy of evaluating the lubricity of the oil.

 In a specific embodiment of the device, the radial blades are located at an angle to the axis of the shaft.

 This arrangement of the blades imparts to the test oil, along with the rotational movement, also the translational motion along the shaft axis, ordering the ingress of abrasive impurities into the friction bearing unit. This provides an additional technical result of increasing the sensitivity of the friction bearing assembly to the concentration of abrasive impurities and, accordingly, the accuracy of evaluating the lubricity of the oil by a generalized index. In addition, this type of movement of oil in the housing of the device facilitates its washing after testing.

 The drawing shows a diagram of a device in longitudinal section.

 The device contains a four-ball and bearing friction units located inside the housing 1. The four-ball friction unit consists of three stationary balls 2, mounted in the cartridge 3, and a ball 4, supported on the balls 2 and fixed on the shaft 5. The bearing friction unit is a ball bearing 6, the inner ring of which is mounted on the shaft 5, and the outer one in the cage 7 with the possibility of movement in it in the axial direction. The ball 4 on the shaft 5 is fixed by a nut 8 on which radial blades 9 are fixed, located at an angle to the axis of the shaft 5. An electric motor (not shown) of the shaft drive 5 is fixed on the housing 5. A spring 10 is mounted in the cage 7, resting one end on the shoulder of the cage, and the other on the end of the bearing 6. A cover 11 is screwed onto the housing 1 to load the spring 10, the value of which is set on a scale applied to the cover. To fill with oil, a filler cup 12 is installed on the housing 1. The holder 7 and the cartridge 3 are electrically isolated from the housing 1 by the bushings 13, 14 and 15. On the holder 7 and the cartridge 3, current collectors 16, 17 are installed, as well as an end current collector at the end of the motor shaft . An electric measuring device (not shown in the drawing) is connected to the current collectors to measure the thickness of the lubricant layer in the friction units by the voltage drop (normal glow discharge method). To drain the oil, the fitting 18 is screwed into the housing.

 The device operates as follows.

 A sample of oil is poured through the cup 12 into the housing 1, the electric motor is turned on and the necessary load of the friction units is set by loading the spring 10. For this, the cover 11 is screwed onto the housing 1. The outer race of the bearing 6 is displaced in the race 7, and the spring 10 is compressed, transferring to the bearing and four-ball friction units load, the value of which is set on a scale on the cover 11. The blades 9 impart rotational movement to the oil, as a result of which mechanical abrasive materials are prevented from entering the four-ball friction unit this, because they are driven by centrifugal forces to the periphery. The influence of these impurities on the thickness of the lubricating layer in the four-ball friction unit disappears, which increases the accuracy of the estimation of the lubricity of the oil.

 Since the blades 9 are located at an angle to the soybean shaft 5, translational is also reported along with the rotational movement. Directed to the bearing 6 (due to the direction of rotation of the shaft 5 or the direction of inclination of the blades 9, respectively), abrasive impurities thrown to the periphery increase the sensitivity of the friction bearing assembly to the concentration of the friction in the oil.

 By sequentially measuring the thickness of the lubricating layer in the four-ball and bearing friction units, a generalized lubricity index of the oil is determined.

 After the test, the oil is drained and the device is washed with the motor turned on with washing liquid.

 The device improves the accuracy of rapid assessment of the lubricity of oils.

Claims (2)

 1. A device for evaluating the lubricity of oils, comprising a housing, a friction bearing assembly installed inside the housing on a rotating shaft, and a four-ball friction assembly mounted on the shaft end, characterized in that radial vanes are fixed in the area of the four-ball friction assembly on the shaft end.  2. The device according to claim 1, characterized in that the radial blades are located at an angle to the axis of the shaft.