Investigation of return movement process of vibrocleaver blade

The lack of the necessary amount of equipment for winter maintenance, significant precipitation leads to a decrease in the efficiency of roads. Inside, courtyards and sidewalks are also covered with a layer of compacted snow due to untimely snow removal. The mechanical method of breaking compacted snow is currently insufficiently studied and so far there is no effective equipment to combat snow and ice formations. A peculiarity of the process of compacted snow destruction in the mode of “vibration cutting” is intermittent contact of the blade with the destroyed medium. Condition of steady mode of vibration cutting is criterion of vibration scraper blade release from contact with medium to be destroyed. The purpose of the study is to establish the time at which the contact of the blade with compacted snow is interrupted. Obtained results of calculations make it possible to set values at which vibration cutting mode is possible and to select parameters of hydraulic accumulator, which provides movement of the vibrocleaver blade of compacted snow.


Introduction
The role of roads in the Far East is especially great. Highways -in most regions are the only mode of transport. The lack of the necessary amount of equipment for winter maintenance [1-7], significant precipitation leads to a decrease in the efficiency of roads.
The fallen snow forms a layer of compacted snow, which has reduced coupling qualities, at which the transport speed decreases, the number of accidents and injuries of traffic participants increases.
Inside, courtyards and sidewalks are also covered with a layer of compacted snow due to untimely snow removal.
The main method of breaking a layer of compacted snow is chemical using salts that negatively affect the environment [5,6]. The mechanical method of breaking compacted snow is currently insufficiently studied and so far there is no effective equipment to combat snow and ice formations.
Finding ways to improve the efficiency and performance of snow removers remains an urgent task. In order to solve this problem, experts of many countries on the winter road maintenance and transport facilities have conducted significant studies [8,9].

Materials and methods
Pacific State University has developed several prototypes of equipment for the destruction of compacted snow on roads and sidewalks using the vibration pulse effect of a blade on a layer of snow and ice [8,9].
The working process of a compacted snow vibrocleaver, designed to destroy snow-ice formations on sidewalks in a mechanized way, is distinguished by a pulse loading mode. The cutting force IOP Publishing doi:10.1088/1757-899X/1103/1/012012 2 depends on the parameters of the layer of snow to be cut: density, depth and width of the cut, angle of cutting, as well as air temperature. In addition, the cutting force is characterized at the beginning of the process of interaction of the blade of the blade with snow by an increase in its value, and then, with chips of snow particles, a sharp decrease in the maximum values characteristic of the destruction of solid brittle media.
The impulse method of interaction of working bodies with the medium finds increasing application. There is a problem of creating simple and reliable vibration exciters. A new type of pump hydropulser is proposed in Russian Patent No. 2162030 ( fig. 1).

Figure 1. Gear type hydraulic pulser design diagram
Peculiarity of gear-type hydropulser is cutout in contacting teeth of windows 1 in order to preserve kinematic connections between gears 2, 3. During rotation of gears with full teeth, working fluid is sucked in and pumped into working cavity of hydraulic propeller 4. Pressure at output of hydraulic pump-pulsator grows under action of elastic force of spring 5. At the moment of interaction of teeth with openings, pressure chamber 6 of hydraulic propeller 4 communicates with suction chamber 7 of hydraulic pump and under action of compressed spring 5 rod of hydraulic propeller 4 moves to initial position, displacing working fluid into suction line. The process of overflow of the working fluid from the delivery line to the suction line is stopped during the period when the conventional teeth begin to interact, and the working fluid again begins to be pumped into the working line of the hydraulic propeller.
Filling of suction line and makeup of possible leaks in hydraulic pusher 4 is performed through check valve 8 under pressure 0 0.3 0.5 p  MPa. Such pressure provides better suction conditions for the working fluid by the pulsator pump. Hydraulic pneumatic accumulator 9 serves as a reservoir and is filled with volume of working fluid supplied from drain line of the main hydraulic system.
A peculiarity of the process of compacted snow destruction in the mode of "vibration cutting" is intermittent contact of the blade with the destroyed medium.
The working process consists at the initial stage of introducing the blade into the compacted snow with movement to the position 0 x , and then when the gear windows are opened, the blade returns to the initial position and simultaneously moves forward with the speed of the base machine M V . The blade cutting edge coordinate will be The purpose of the study is to establish the time during which the contact of the blade with compacted snow is interrupted.
The process of returning the blade is presented in the form p -pressure in hydraulic pusher cavity. Pressure in front of hydraulic push-rod decreases sharply from initial position 0 p , and then increases as blade returns to initial position due to overcoming resistance to movement of working fluid [9,10] where  is the coefficient that takes into account the intensity of the initial pressure drop,  cm, the speed of return movement can ensure that the blade comes out of contact with the medium to be destroyed.

Conclusion
The obtained calculation results make it possible to set the values at which the vibration cutting mode is possible and to select the parameters of the hydraulic accumulator, which provides movement of the blade of the vibrocleaver of compacted snow up to the values cm.

References
[1] Sajed Sadati S M, Cetin K, Ceylan H, Sassani A and Kim S 2018 Energy and thermal performance evaluation of an automated snow and ice removal system at airports using numerical modeling and field measurements Sustainable Cities and Society 43 238-250 0 0.8 x 