RU2272107C1 - Hydraulic drive for pneumowheel dredger - Google Patents

Abstract

FIELD: mechanical engineering, particularly hydraulically driven dredgers.

SUBSTANCE: drive comprises power plant with controlled power pumps having servo control taps, gear-box, hydraulic motors and hydraulic equipment. Hydraulic equipment has hydraulic distributor with address travel spool and its servo control taps, power hydraulic lines and servo control loop with hydraulic lines. The controlled power pumps may supply predetermined volume of working liquid at zero pressure in servo control lines thereof. Hydraulic lines for servo control of address travel spool have additional circuit including control unit, servo control lines and logical hydraulic OR valve with two inlet and one outlet taps. Hydraulic lines of servo control circuit included in additional loop are connected with inlet taps of hydraulic OR valve having outlet tap communicated with servo control taps of address travel spool.

EFFECT: provision of no-failure gear actuation in standing still dredger.

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Description

The invention relates to the field of mechanical engineering, namely, pneumatic-wheel excavators with hydraulic drive.

The hydraulic drive of a pneumatic wheel excavator is known (see Rannev A.V. Single-bucket excavators. M., Higher School, 1991, EO-3323 Excavator, p. 119), selected as a prototype, containing a power plant with adjustable power pumps, with servo control taps, a hydrodistributor with servo taps, power hydraulic lines, a servo control circuit with hydraulic lines, a gearbox with hydraulic motors, the gear shift of which is carried out by a gearshift with a servo drive, cardan shafts, front and rear day bridges, wheels. The gearbox, which is a gear reducer, has a primary shaft to which torque is transmitted from the gears on the output shaft of the hydraulic motor, as well as a secondary shaft that transmits torque to the driveshafts and then to the front and rear axles and wheels. Torque from the primary shaft to the secondary is transmitted as follows. The gears of the first and second gears are rigidly fixed on the input shaft. A movable gear is installed on the splines of the secondary shaft, which is moved along the shaft axis by the gear shift mechanism. In the "first speed" position, the movable gear receives torque from the first gear. In the "second speed" position, the movable gear receives torque from the gear of the second gear. When this occurs, the inclusion of the first or second gear, respectively. In the intermediate neutral position, the movable gear is not engaged and the torque is not transmitted to the secondary shaft from the primary shaft.

A significant drawback of the known drive is that when the transmission is “in place” (on a motionless excavator), gears are often not engaged due to the fact that the movable gear does not mesh with the gear of the first or second gear due to the arbitrary position of their teeth relative to each other. The gears abut against the ends of the teeth. The operator has several times to engage the transmission. In many drive designs, the so-called “gear grinding” is used to eliminate this drawback, that is, rounding the end profile of the teeth (see Engineering. Encyclopedia. Ed. Reshetova D.N., Volume IV-I, M., Engineering, 1995, p. 802). However, the defect is not completely eliminated, only the probability of not shifting gears is reduced. For reliable gear shifting “from the spot”, it is necessary, in addition to moving the movable gear along the splines of the secondary shaft, so that the gears mounted on the input shaft rotate at low speed (hereinafter, the low speed of the shaft means a speed of the order of 0.5 r / s ) In known drives, it is difficult to achieve a low speed of rotation of the input shaft when gears are engaged, because adjustable power pumps with so-called “positive” control (with a feed that is inversely proportional to the load on the actuator, for example, on a hydraulic motor) when applying control pressure in their servo control line, they immediately begin to work at maximum feed, since the gears of the input shaft are not engaged when the gear is not engaged and do not create a load for hydraulic motors. As a result, the hydraulic motors transmit torque to the input shaft with a maximum speed, leading to non-inclusion of the gear. In the case of using regulated power pumps with the so-called "proportional" control (with a supply proportionally changing depending on the magnitude of the control pressure), it is difficult for the operator to set the required rotation speed of the gearbox hydromotors. This leads to instability of gear shifting. In both cases, the power rotation of the input shaft when the gear is not engaged will result in damage to the gearbox or failure of the hydraulic motors.

The aim of the present invention is to provide a hydraulic drive design for the pneumatic wheel excavator, free from the above disadvantage. This goal is achieved by the fact that in the hydraulic drive of the pneumatic wheel excavator, adjustable power pumps are made with the possibility of supplying a working fluid in a certain volume in the absence of pressure in their servo control lines, and an additional circuit consisting of a control unit, a servo control hydroline is included in the servo control line of the address valve and a logical hydraulic valve OR with two input and one output taps, while the hydraulic lines of the servo control loop and the servo control hydroline Nia additional circuit coupled to the input hydraulic valve or tap, an output tap is connected to the tap address servo spool stroke of the control valve.

The claimed technical features are significant, as they affect the technical result achieved.

In the study of other known technical solutions in the art, signs that distinguish the claimed technical solution were not identified. This allows us to conclude that the claimed technical solution has novelty and does not follow explicitly from the existing level of technology.

The proposed technical solution can be applied in industry in the manufacture of pneumatic wheel excavators.

The invention is illustrated by drawings, where figure 1 shows a schematic hydraulic diagram of the drive of a pneumatic wheel excavator, figure 2 shows an adjustable power pump.

The hydraulic drive of the pneumatic wheel excavator includes a power unit with adjustable power pumps 1, with servo control bends 2, a gearbox with hydraulic motors 3, a directional control valve 4 with address 5 spool, having servo bends 6, power hydraulic lines 7, servo control hydraulic lines 8, blocks 9 and 10 control mechanism 11 gear box and the spool 12 control mechanism 11 gear.

The hydraulic control lines 8 have an additional circuit consisting of a control unit 13, hydraulic control lines 14 and a logical hydraulic valve 15 OR.

Adjustable power pumps 1 are configured to supply a working fluid in a certain volume in the absence of pressure in their servo control lines. This is achieved by the fact that an adjusting screw 17 is installed in the pump housing 16, which limits the minimum angle of rotation of the distributor 18 of the inclined cylinder block 19, which ensures a fixed volume of the minimum pump flow in the absence of pressure in its servo control line.

Drive operation.

When the transmission is in place, the operator turns on the control valve 12, the control unit 9 and the additional servo control circuit control unit 13, while the working fluid is supplied through the servo control hydraulic lines 14 and the OR 15 hydraulic valve to the servo control taps 6 of the address valve 5 of the stroke and moves it to the desired position direction (forward or reverse), while the power lines of the hydraulic motors 3 of the gearbox are connected to the pressure lines of the regulated power pumps 1, which, due to the lack of pressure in their lines oupravleniya produce minimum flow rate of the working fluid, thereby ensuring a minimum speed hydraulic motors, besides the working fluid through the control valve 12 is supplied to the switching mechanism 11 and the gearbox tends to enter the movable gear output shaft in engagement with the pinion gear. And since the input shaft rotates at a low speed, a guaranteed transmission is engaged.

The excavator begins to move slowly, which is a sign of the gear engaged, after which the operator turns off the control unit 13 and turns on the control unit 10, while the working fluid through the hydraulic control lines 8 of the servo control valve 15 OR acts on the address valve 5 of the stroke, as well as through the taps 2 of the servo control power pump regulator 1, while the pump flow increases, and the excavator smoothly increases the speed of movement to maximum.

Claims (1)

A hydraulic drive drive of a pneumatic wheel excavator, comprising a power unit with adjustable power pumps having servo taps, a gearbox, hydraulic motors, hydraulic equipment, including a directional valve with an address stroke spool and its servo taps, power hydraulic lines, servo control circuit with hydraulic lines, characterized in that it is adjustable pumps are made with the possibility of supplying a working fluid in a certain volume in the absence of pressure in their servo-control lines, and in the hydraulic line and the servo control of the address valve of the stroke includes an additional circuit consisting of a control unit, servo control lines and a logical hydraulic valve OR with two input and one output taps, while the servo control circuit and the servo control auxiliary circuits are connected to the input taps of the OR valve, the output tap of which is connected to by servo control taps with an address spool of the directional control valve stroke.

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