RU235348U1 - DISC CULTIVATOR FOR CARE OF FOREST CROPS - Google Patents

Abstract

The utility model relates to the field of forestry engineering. A disc cultivator for tending forest crops includes a frame with a mounted device, working bodies in the form of two spherical disc batteries, four discs each, fixed on a shaft rotating in two bearing supports with radial single-row ball bearings each. In this case, the bearing supports are equipped with additional radial single-row ball bearings with double-sided seals, two protective washers rotating together with the shaft, two spring thrust rings and annular grooves for them. The bearing support housing seats for the outer bearing rings have a continuous bore for all bearings from one installation on the machine, and the annular grooves for two spring thrust rings are made at the ends of the bearing housing at a distance from each other, which is determined by the formula

B=2S + n ⋅ H,

where B is the distance between the spring thrust rings; S is the thickness of the rotating protective washer; n is the number of bearings, n=5; H is the width of the bearing race. Increased performance and reliability in extreme operating conditions of the disc cultivator for the care of forest crops is ensured. 5 fig.

Description

The utility model relates to the field of forestry engineering, in particular to tools for agrotechnical care of forest crops.

Maintenance of forest crops, which is carried out at the initial stage of growth of forest crops, includes regular weeding and loosening of the top layer of soil between rows and in order to destroy grassy weeds, preserve and accumulate moisture, and create a favorable water-air regime.

The forest furrow cultivator KLB-1.7 is widely known. It is designed for the care of forest crops in clearings, planted along the bottom of furrows or in strips prepared by forest cutters. Depending on the cross-country conditions, it is aggregated with wheeled (MTZ-80 MTZ-82) or tracked (DT-75M, LHT-55) tractors.

The main components of the cultivator are: a frame with a mounted device, working parts and ballast boxes.

The working bodies are made in the form of two disk batteries fixed on the crossbar of the frame. Each battery has four smooth spherical disks with a diameter of 510 mm, which are installed on a square shaft rotating in the plain bearings of the racks. The distance between the disks is usually 175 ... 180 mm. The upper ends of the racks are welded to the lower horizontal plate of the battery body, which is connected to the upper horizontal plate by pivots using a bolt (axis) and curvilinear grooves with adjusting bolts and is fixed with a bolt. On the upper plate there are lugs, which are pivotally connected with a tie bolt to brackets welded to the rear vertical plate. A U-shaped frame is welded to this plate, to which the upper plate assembled with the disk battery is attached using shock-absorbing springs. The rear vertical plate is pivotally connected to the front plate with the ability to adjust their position. The front vertical plate is attached to the crossbar of the frame using clamps. This fastening of the disk batteries allows changing the angle of attack (the angle between the axis of the batteries and the horizontal) and their position in the vertical plane.

The angle of attack is adjusted in the range from 0 to 30° with an interval of 10°. To change the position of the disk battery in the vertical plane (up to 20° with an interval of 5°), turn the rear vertical plate relative to the front plate. Such adjustment is carried out when caring for crops in furrows, when it is necessary to process (loosen) the layers and the bottom of the furrow near a row of plants. By adjusting the angle of attack, high-quality soil cultivation to a depth of 6 ... 12 cm is achieved. On heavy soils, the required depth of cultivation is achieved not only by increasing the angle of attack, but also by loading ballast into the boxes.

Since forest crops have a low above-ground part in the first year of growth, the first care is carried out with the disk batteries in a staggered position. In this case, the batteries are installed with the convex (spherical) part of the disks inward (towards the row of crops). In subsequent years, staggered care is alternated with upturned care, for which the right and left batteries are swapped.

The width of the protective zone on each side from a row of forest crops to the first internal disk of the battery is adjusted within 20...40 cm by moving the bodies together with the disk batteries along the crossbar of the cultivator frame.

The cultivator's working width is 1.7 m, weight is 510 kg, productivity per 1 hour of basic time is 3...4.5 km.

To adjust the working parts, the cultivator must be installed on stands.

The radial clearance in the bearings of the disk battery is checked by moving it up and down.

If the runout exceeds 2...2.5 mm, it is necessary to unscrew the bolts securing the bearing housing to the rack, remove the cover, adjusting linings and remove the liners from the bearing housing. After this, wash the parts in diesel fuel, remove one or two linings on each side and assemble the bearing. When tightening the bolts, it is necessary to periodically rotate the housing with the bearing. After fully tightening the bolts, the bearing should rotate freely by hand without noticeable radial play. The normal clearance should be within 0.5...1 mm.

The angle of attack of the battery disks (0…30°) is adjusted by turning the lower horizontal plate relative to the upper plate. For these purposes, the upper plate has four adjustment holes for changing the angle of attack at intervals of 10°. When adjusting, it is necessary to unscrew and remove the fixing bolt from the holes in the plates, and loosen the bolt, which is the axis of rotation, and the adjusting bolts on the curvilinear grooves by unscrewing their nuts by several turns. Then manually turn the battery until the hole in the lower plate aligns with the hole that corresponds to the required angle of attack on the upper plate, after which install the fixing bolt and tighten the bolted connections.

Changing the angle of inclination of the batteries in the vertical plane (0...20° with an interval of 5°) is done in a similar manner, combining the necessary holes in the rear and front vertical plates (see the book by V.F. Zinin, V.I. Kazakov, O.G. Klimov “Technology and mechanization of forestry work” M.Academa, 2002, pp. 133...136).

However, the described cultivator has a significant drawback due to the fact that it is equipped with sliding bearings consisting of two halves (liners), which require laborious adjustment of radial clearances by removing one or two gaskets and washing each time in diesel fuel.

During operation, the radial clearance between the bearing liners reaches 0.5 to 2.5 mm and higher, and as a result, due to abrasive dirt particles getting into them, they wear out quickly, i.e., they have a short service life.

Also known is a mounted disc cultivator for tending forest crops in unstumped clearings, comprising a frame, two rotary disc sections, each of which comprises a shaft of circular cross-section, with a set of spherical discs on it, mounted in two bearing supports located between the outer and the spherical discs following it, according to the utility model, each support is equipped with two rolling bearings, wherein the distance h between the inner ends of the outer bearing races is 0.011N<h<2.5N, where H is the width of the bearing race.

Radial or radial-thrust single-row ball bearings are used as rolling bearings, with the distance h between the inner ends of the outer races being ensured by a ring stop between them.

The bearing support housing is equipped with side covers that press against the end of the outer bearing races, while dust seals are installed in the seat on the inside of the cover.

Between the outer end of each support bearing and the nearest harrow disc, a spacer sleeve is installed on the shaft, and the surface of the inner hole of each seal interacts with the outer surface of the spacer sleeve.

A spacer sleeve is installed between the harrow discs, located on the inside of each bearing support, providing the required distance between the harrow discs (175...180 mm).

The shaft on which the harrow discs and the inner bearing races are mounted is provided with a nut for tightening them, provided with a locking element, and at the other end the shaft has a cap or groove for installing a locking ring. See the description of the patent for utility model No. 148591 "Mounted disc cultivator for caring for forest crops, which in its purpose and technical essence is closest to the claimed technical solution and is accepted as its prototype.

However, the cultivator adopted as a prototype has significant drawbacks due to the fact that the rolling bearings in the bearing support housing are installed with a gap between the ends of the outer rings due to the annular stop between them. The presence of the annular stop in the bearing housing during its manufacture forces the machining of the seats to be performed sequentially in two installations on the machine, and this does not guarantee the necessary coaxiality of the bearing seats, and misalignment above the radial clearance in the bearings themselves causes their skew during assembly, and the ability to compensate for skews in single-row radial ball bearings is very limited. Even the slightest skew significantly reduces the service life of the bearing and is accompanied by a significant increase in the noise level.

Working conditions during forest crop maintenance are extreme. During operation, spherical disk working bodies installed at an angle of attack, when encountering and overcoming underground roots, logging residues and stumps of different heights, themselves perceive and transmit to the bearing supports a significant alternating dynamic load in both the radial and axial directions. However, if the bearings in the support simultaneously perceive radial loads approximately equally (equally), then the axial load in each support, due to the presence of a gap between the inner rings of the bearings, is perceived by only one of the bearings, and axial loads exceeding the permissible limits can cause rapid failure of the radial ball bearings. The listed disadvantages reduce the performance and operational reliability of the cultivator as a whole.

The objective and purpose of the proposed technical solution is to increase the performance and reliability of the cultivator in extreme operating conditions.

The solution to the set problem is achieved by the fact that in a disc cultivator for caring for forest crops, including a frame with a mounted device, working bodies in the form of two spherical disc batteries, four discs each, fixed on a shaft rotating in two bearing supports with radial single-row ball bearings each, the bearing supports are equipped with additional radial single-row ball bearings with double-sided seals, two protective washers rotating together with the shaft, two spring thrust rings and annular grooves for them, while the seats of the bearing support housings for the outer rings of the bearings have a continuous bore for all bearings from one installation on the machine, and the annular grooves for two spring thrust rings are made at the ends of the bearing housing at a distance from each other, which is determined by the formula

B=2S + n ⋅ H,

where B is the distance between the spring thrust rings;

S – thickness of the rotating protective washer;

n – number of bearings, n=5;

H – bearing race width.

The proposed technical solution is explained graphically, where Fig. 1 shows a cultivator for caring for forest crops - side view; Fig. 2 - a cultivator for caring for forest crops - top view; Fig. 3 - shows a spherical disk battery with bearing supports in section - left section; Fig. 4 - shows the bearing support housing in assembly; Fig. 5 - shows a graph of the dependence of the effect of dynamic load on the amount of wear of a rolling bearing during oxidative wear.

The disc cultivator for caring for forest crops includes a frame 1 with a mounted device 2, working bodies in the form of two spherical disc batteries 3, four discs 4 each, fixed on a shaft 5 rotating in two bearing supports 6 with five radial single-row ball bearings with double-sided seals 7 each. Two protective washers 8 rotating together with the shaft, two spring thrust rings 9 and annular grooves 10 for them, while the seats 11 of the housings 12 of the bearing support for the outer rings of the bearings have a continuous bore for all bearings from one installation on the machine, and the annular grooves for two spring thrust rings are made at the ends of the bearing housing at a distance from each other, which is determined by the formula

B=2S + n ⋅ H,

where B is the distance between the spring thrust rings;

S – thickness of the rotating protective washer;

n – number of bearings, n=5;

H – bearing race width.

Spherical disks 4 are assembled on a common shaft 5 at a distance of 175...180 mm from each other and are fixed in the axial direction using spacer bushings of different lengths 14, 15, washers 16 and nuts 17 with locknuts 18.

Single-row radial ball bearings with double-sided seals or protective washers do not require any adjustments, contain the required amount of grease between the seals for the entire service life and are maintenance-free. Most importantly, these bearings, along with the perception of radial loads, due to their design features are also capable of perceiving axial loads acting in both directions along the shaft axis up to 70% of the unused permissible radial load.

The service life of rolling bearings is largely determined by their operating conditions. Forest disc cultivators are machines that operate in particularly difficult conditions. Their working parts and bearing units are subject to significant alternating loads with a dynamic nature of their application. In rolling bearings, the loads are supported by the working surfaces of the rings and rolling elements.

The depth and degree of deformation of the surface layers of the metal of the rings and rolling elements directly depend on the magnitude of the loads and the contact stresses associated with them, and the type of wear process occurring on the friction surfaces depends on the degree of deformation. Thus, when working in pure oil (without abrasive) under contact stresses, the normal process of oxidative wear will occur, the intensity of which is minimal. With increasing loads, fatigue wear occurs, leading to the destruction of the working surfaces. The described phenomenon is well illustrated by the graph of the dependence of wear during rolling friction on the degree of load dynamism (see Fig. 5). It is evident from the graph that in a significant range, load fluctuations (vibration) have virtually no effect on the amount of wear. However, upon reaching a certain, critical value, the value of which depends on the bearing design, the type of lubricant in the contact zone, wear increases sharply and can exceed normal by tens of times.

This character of the dependence of wear on load fluctuations (vibrations) is explained as follows: between the contacting bodies (for example, rolling elements and bearing races) there is an oil layer that separates them and prevents metallic contact. The oil film is capable of withstanding a certain load without breaking and compensating for its fluctuations up to a certain critical value. However, when the fluctuations increase above the critical value for the given conditions, the oil film is destroyed. In this case, direct metallic contact occurs, which sharply increases wear and causes premature failure of the rolling bearings. Moreover, this destruction occurs the faster, the greater the load.

One of the ways to reduce the load on the ring tracks and rolling elements is to increase the number of bearings in the disc cultivator housing, which is limited by the distance between the disks (175...180 mm). Such a distance between the disks allows placing 5 bearings of the light and medium series of normal accuracy class in the bearing support housing. The bearing seats in the housing, processed in one installation and in one pass of the cutting tool, guarantee their assembly without axial displacements, especially since all bearings are assembled on one shaft, and the tolerances of the ring sizes in width, both internal and external, for radial single-row ball bearings have the same limits.

In such a design of the bearing support, during the operation of the cultivator, the load transmitted to them by spherical disks both in the radial and axial directions is perceived by all bearings simultaneously and is distributed between them almost equally, which will ensure an increase in the performance and reliability of the cultivator as a whole in extreme operating conditions.

This increases the overall performance and reliability of the cultivator under extreme operating conditions.

The applicant has manufactured prototypes of cultivators with the proposed bearing supports, which have been tested under extreme operating conditions for two seasons. Diagnostics conducted to determine the measurement of their condition and clearances between the rolling elements and the running tracks confirmed the correctness of the solution to the problem, in connection with which the utility model can be successfully used in the production of cultivators for the care of forest crops.

Claims (6)

A disc cultivator for tending forest crops, comprising a frame with a mounted device, working bodies in the form of two spherical disc batteries, four discs each, secured on a shaft rotating in two bearing supports with radial single-row ball bearings each, characterized in that the bearing supports are equipped with additional radial single-row ball bearings with double-sided seals, two protective washers rotating together with the shaft, two spring thrust rings and annular grooves for them, wherein the bearing support housing seats for the outer bearing rings have a continuous bore for all bearings from one installation on the machine, and the annular grooves for two spring thrust rings are made at the ends of the bearing housing at a distance from each other, which is determined by the formula B=2S + n ⋅ H, where B is the distance between the spring thrust rings; S – thickness of the rotating protective washer; n – number of bearings, n=5; H – bearing race width.