RU2810910C1 - Walk-behind tractor transmission - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: transmission of the walk-behind tractor comprises a gearbox housing with an output shaft located inside, composed of two output half-shafts, fixed against axial movement and configured to rotate independently relative to each other, connected to the input shaft through sprocket blocks. The gearbox housing is equipped with an intermediate shaft having a drive cardan and drive pulleys. The input shaft is made up of two input half-shafts secured against axial movement and capable of independent rotation relative to each other. On the outer part of the input half-shafts, driven pulleys are installed, connected to the drive pulleys by V-belts with tensioning mechanisms equipped with individual controls that provide the clutch on and off modes.

EFFECT: reduction in the labour intensity of controlling the walk-behind tractor when manoeuvring, an increase in its cross-country ability, and an increase in the clutch life.

1 cl, 3 dwg

Description

The invention relates to the field of mechanical engineering, namely to means of mechanization of agricultural work on personal plots, in gardens and vegetable gardens for individual use.

The transmission is designed to change the amount of torque, as well as to transmit torque from the engine crankshaft to the drive wheels and/or cutters of the walk-behind tractor.

A chain gearbox of a walk-behind tractor is known, the gear ratio of which is more than 2.5 (see RF patent for utility model No. 2694 class A01B 3/50, 1996). The wheels of the walk-behind tractor are installed at the ends of the solid output shaft of the gearbox.

The disadvantages of a walk-behind tractor with such a gearbox design are difficulty in controlling, low maneuverability, and increased fuel consumption when turning and driving on uneven roads.

An analogue of the invention is the design of a two-speed chain gearbox of the MB-1 “Neva” walk-behind tractor (see online source: https://pahalka.ru/motobloki/motobloki-neva/motoblok-neva-mb-1) in an elongated housing in which the a continuous input shaft connected through three blocks of sprockets to the output shaft, at the ends of which there are holes for fixing to the shaft of the drive wheels or soil tillers. The double sprocket is pushed apart in the gearbox housing using a bushing and washer.

When driving on turns or on uneven roads, the drive wheels of the walk-behind tractor travel different distances. Therefore, if both wheels, having a common solid shaft, receive rotation from the engine at the same speed, then one of them will slip. The operator is forced to exert greater effort to “drag” the sliding wheel, causing increased tire wear and increased fuel consumption.

The disadvantages of the known gearbox design are the low maneuverability of the walk-behind tractor, the need for high physical effort by the operator when one of the drive wheels slips and, as a consequence, increased tire wear and increased fuel consumption.

The prototype of the claimed invention is a walk-behind tractor gearbox (see RF patent for invention No. 2348135 class A01B 71/00, 2009), containing a gearbox housing with an output shaft located inside, composed of two output half-shafts, fixed from axial movement and made with the possibility of independent rotation relative to each other, connected to the input shaft, through sprocket blocks.

The disadvantage of such a walk-behind tractor gearbox is the low maneuverability of the walk-behind tractor, the need for the operator to exert physical effort to turn, turn or maneuver the walk-behind tractor, leading to its rapid fatigue, increased wear of the clutch components, as well as low maneuverability due to maneuvering with the clutch disengaged for both drive wheels and/or cutters walk-behind tractor.

The technical result of the invention is to reduce the labor intensity of controlling a walk-behind tractor when maneuvering, increase its cross-country ability, and also increase the clutch life.

The technical result is achieved by the fact that in the transmission of a walk-behind tractor, containing a gearbox housing with an output shaft located inside, composed of two output half-shafts, fixed from axial movement and configured to rotate independently relative to each other, connected to the input shaft, through sprocket blocks, according to the invention the gearbox housing is equipped with an intermediate shaft having a drive cardan and drive pulleys, and the input shaft is made up of two input half-shafts, secured against axial movement and made capable of independent rotation relative to each other, and driven pulleys are installed on the outer part of the input half-shafts, communicating with the drive pulleys V-belts with tensioning mechanisms equipped with individual controls that provide clutch on and off modes.

The essence of the invention is illustrated by drawings where: Fig. 1 - shows a longitudinal section of the walk-behind tractor transmission; in fig. 2 - section A-A in Fig. 1 (clutch engaged mode); in fig. 3 - section A-A in Fig. 1 (clutch disengaged mode).

For the sake of clarity, the drawings present only those elements that are necessary to understand the invention, and related elements well known to those skilled in the art are not presented.

The transmission of the walk-behind tractor (Fig. 1) contains a gearbox housing 1 with an output shaft located inside, composed of two output half-shafts 2 and 3, fixed from axial movement and configured to rotate independently relative to each other, an input shaft made up of two input half-shafts 4 and 5, fixed from axial movement and made with the possibility of independent rotation relative to each other, connected to the output half-shafts 2 and 3, through sprocket blocks 6 and 7 by chain drives 8, 9, 10 and 11. Driven pulleys are installed on the outer part of the input half-shafts 4 and 5 12 and 13. The intermediate shaft 14 is installed inside the gearbox housing 1 in its upper part, has a drive cardan 15 and drive pulleys 16 and 17 communicated with driven pulleys 12 and 13, V-belts 18 and 19 with tension mechanisms 20 and 21, equipped with individual controls 22 and 23 (which can be made in the form of levers connected by cables to the walk-behind tractor control handles (not shown in the figures)), providing modes of the clutch on and off (Fig. 2, 3).

The walk-behind tractor transmission works as follows. During the operation of the walk-behind tractor, the torque from the internal combustion engine (not shown in the figures) is transmitted to the drive cardan 15, rotating the intermediate shaft 14 with drive pulleys 16 and 17, which, using V-belts 18 and 19, drive driven pulleys 12 and 13 with input half-shafts 4 and 5 of the input shaft, from which the sprocket blocks 6 and 7 rotate through chain drives 8 and 9, driving through chain drives 10 and 11 the output half-shafts 2 and 3 of the output shaft, on which the drive wheels and/or cutters are mounted (not shown in the figures) ).

Tensioning mechanisms 20 and 21, controlled by individual controls 22 and 23 (by the operator’s action on the walk-behind tractor control handles (not shown in the figures)), carry out tension (clutch on mode (Fig. 2)) or sagging (clutch off mode (Fig. 3)) V-belts 18 and 19, thereby forming or breaking the flow of torque between the drive pulleys 16 and 17 and the driven pulleys 12 and 13, and consequently, starting or stopping the rotation of the half-shafts 2 and 3 of the output shaft with the drive wheels mounted on them and /or cutters (not shown in the figures).

Modes of operation of the walk-behind tractor transmission during maneuvering, including: turning, turning and moving along a curved path.

When turning the walk-behind tractor, the operator loosens the tension (Fig. 3) of the V-belt 18 or 19 (guided by the selected direction of rotation) by individual controls 22 or 23, respectively, thereby breaking the flow of torque between the drive pulley 16 and the driven pulley 12 or between the drive pulley 17 and driven pulley 13 (depending on the selected direction of rotation). As a result, one of the output half-shafts 2 or 3 stops together with the drive wheel and/or cutter installed on it (not shown in the figures), and the rotating half-shaft 3 or 2, respectively, with the drive wheel and/or cutter installed on it (in the figures not shown), describes an arc around it, thereby producing a turn, the angle of which is controlled by the operator by acting on the individual controls 22 or 23 (depending on the selected side of the turn).

When turning the walk-behind tractor, the operator loosens the tension of the V-belt 18 or 19 (guided by the selected side of the turn) by individual controls 22 or 23, respectively, thereby breaking the flow of torque between the drive pulley 16 and the driven pulley 12 or between the drive pulley 17 and the driven pulley 13 (in depending on the selected side of the turn). As a result, one of the output half-shafts 2 or 3 stops together with the drive wheel and/or cutter installed on it (not shown in the figures), and the rotating half-shaft 3 or 2, respectively, with the drive wheel and/or cutter installed on it (in the figures not shown), describes a semicircle around it, thereby producing a turn, which is controlled by the operator by acting on the individual controls 22 or 23 (depending on the selected side of the turn).

When the walk-behind tractor moves along a curved path, the operator briefly loosens the tension of the V-belt 18 or 19 (guided by the selected side for maneuvering) with individual controls 22 or 23, respectively, thereby briefly breaking the flow of torque between the drive pulley 16 and the driven pulley 12 or between the drive pulley 17 and driven pulley 13 (depending on the direction of the trajectory of movement). As a result, one of the output half-shafts 2 or 3 stops briefly together with the drive wheel and/or cutter installed on it (not shown in the figures), and the rotating half-shaft 3 or 2, respectively, with the drive wheel and/or cutter installed on it (on figures not shown), describes an arc around it, thereby producing movement along a curved trajectory which is controlled by the operator, acting on individual controls 22 or 23 (depending on the direction of the movement trajectory).

When maneuvering the walk-behind tractor:

- the operator does not put physical effort on the steering wheel, but works only with individual controls 22 and 23, which reduces the complexity of controlling the walk-behind tractor when turning, turning and maneuvering;

- the torque of the internal combustion engine is used, transmitted to the drive wheel and/or cutter, and not the muscular strength of the operator, due to which the change in direction of movement occurs faster than in the prototype, and therefore maneuverability increases;

- on an uneven road or rough terrain, torque from the internal combustion engine will always be transmitted to one of the wheels and/or cutters, which will increase cross-country ability;

- there is minimal wear of the clutch components due to their short-term slipping (the period of completing a turn, turning and maneuvering, which proceeds faster due to the use of the internal combustion engine, and not the muscular strength of the operator).

The use of the invention will make it possible to: reduce the complexity of controlling a walk-behind tractor when maneuvering, increase its cross-country ability, and also increase the clutch life.

Claims (1)

A walk-behind tractor transmission containing a gearbox housing with an output shaft located inside, composed of two output half-shafts, fixed against axial movement and configured to rotate independently relative to each other, connected to the input shaft through sprocket blocks, characterized in that the gearbox housing is equipped with an intermediate shaft, having a drive cardan and drive pulleys, and the input shaft is made up of two input half-shafts, secured against axial movement and configured to rotate independently relative to each other, and on the outer part of the input half-shafts there are driven pulleys installed, connected to the drive pulleys by V-belts with tensioning mechanisms, equipped with individual controls that provide clutch on and off modes.