The hydraulic system industrial tractor
(57) Abstract:Usage: refers to the total engineering and is intended for use in industrial tractors. The inventive system includes a flow sensor installed in the drain hydroline source of pressure, the device switching off the source of pressure or trouble signal, the power circuit which includes normally closed contact controlled from the mentioned flow sensor. The flow sensor is made in the form of managed dip inductor, the minimum open position which corresponds to the flow of the working fluid in the piston cylinder chamber, and the maximum open - rod in the cylinder chamber. 5 Il. The invention relates to mechanical engineering and is intended for use in industrial tractors.Hydraulic industrial tractors-intensive modes of loading when working bulldozer and Ripper equipment, typical of a significant emergency loss of the working fluid with the failure of the hose, first of all high pressure hoses.A known hydraulic system, which is controlled by the pressure play pressure in the pressure hydroline and decreases or stops the flow in the drain hydroline. This allows to generate a signal to turn off the pump and prevent disaster losses (see ed. St. USSR N 1262145, F 15 B 20/00, 1984).The disadvantage of the hydraulic system is that it does not provide effective control of the availability of disaster losses in the actuator characterized by the change in the flow rate of the working fluid in the drain hydroline during normal operation. Due to the large stroke of the cylinders and their piston rods for stability have relatively large diameters, resulting in a significant difference of displacements of the respective piston and rod ends. The latter circumstance leads to the fact that the flow rate of the working fluid at the discharge the flow into the rod cavity in two or more times the flow rate at the discharge when working piston cavity.Object of the present invention is to reduce disaster losses of the working fluid in the hydraulic systems of industrial tractors, use of long stroke cylinders with one rod.The technical result is achieved in that the flow sensor is made in the form of managed dip inductor, the minimum open position which corresponds to the flow of the operating fluid Bokovoy cylinder chamber.In Fig. 1 shows a schematic diagram of the hydraulic system with electrically controlled by the control valve and the flow sensor of Fig. 2 - schematic of the electrical control circuit of the hydraulic system according to Fig. 1, in Fig. 3 schematic diagram of the hydraulic circuit with valve controlled from the handle, and the control of its working positions by means of limit switch of Fig. 4 schematic diagram of the hydraulic system with hydraulic control working positions of the valve of Fig. 5 structural diagram of the flow sensor.The hydraulic system includes a source of pressure (pump) 1 driven from the electromagnets 2, 3, valve 4, reported working hose 5, 6 with the hydraulic cylinder 7, the pressure hydroline 8 with a pump 1, a drain hydroline 9 tank 10. Pressure hydroline 8 communicated with the drain hydroline 9 through the electrically controlled bypass valve 11 with the electromagnet 12. In the drain hydroline 9 installed sensor 13 flow, schematically depicted as mounted parallel to constantly open throttle 14 and driven by the electromagnet 15 of the throttle 16. Parallel to the sensor 13 is installed, the device switching off the source of pressure or trouble signal, made in the form elergic key 18 power, buttons 19, 20 management respectively electromagnets 2, 3 valve 4 and the electromagnet 12 through diodes 21, 22. Consistently with electrocontact 17 disconnects the source of pressure or trouble signal in the power circuit installed electromagnetic relay 23 with normally open electrocontact 24 having a time delay in the circuit and including electromagnetic relay 25. The relay 25 is irreversible and including a supply signal lamp 26 electrocontact 27.The hydraulic system operates as follows.In the initial position, the key 18 is closed, the button 19, 20 control open, the electromagnets 2, 3, 12, 15 and the relay 23 is deenergized. Open contacts 24, 27, de-energized relay 25, does not light a lamp 26. The valve 4 is in the middle (neutral) position. The bypass valve 11 is opened, the working fluid from the pump under pressure hydroline 8 through the valve 11 and the drain hydroline 9 enters the tank 10 (pump unloaded). Accordingly, there is no flow through the flow sensor 13, there is no pressure drop across the device switching off the source of pressure, a contact 17 which is closed. The valve 4 is in the middle (neutral) position. In the hydraulic cylinder 7 is not Agnitum 2, 15 and through the diode 21 to the electromagnet 12. Accordingly, the valve 4 is switched to the left position, the bypass valve 12 is closed, the throttle 16, the sensor 13 of the flow switches in the right position, reducing its flow section only to the inductor 14 and increasing the hydraulic resistance. In connection with the closing of the valve 11 increases the pressure of the working fluid in the pressure hydroline 8, through the control valve 4 and a working hydroline 5 working fluid enters the piston cylinder chamber 7. Begins to move the piston of the hydraulic cylinder 7 with extension rod. The working fluid from the rod end of the hydraulic cylinder on the working hydroline 6 through the control valve 4 and the drain hydroline 9 is supplied to the sensor 13 consumption and forth in the tank 10. The sensor 13 of consumption, there is a pressure drop, under the influence of which is compressed spring device switching off the source of pressure or trouble signal and accordingly opens its contact 17. As a result, the electromagnetic relay 23 is not receiving power and remain open its contact 24 and the contact 27 of the electromagnetic relay 25, respectively, remains off the lamp 26 of the alarm. To prevent false alarm signcd 24 relay 23 is executed with delay (delay) time expires.Upon release (release) button 19 and the button 20 power supplied to the electromagnet 3 and through the diode 22 to the electromagnet 12. Accordingly, the valve 4 is switched to the right position, the bypass valve 12 is closed, the orifice 16 of the sensor 13 flow switch in the left position, increasing the flow area and reducing its hydraulic resistance. The working fluid from the pump 1 under pressure by the pressure hydroline 8 through the control valve 4 and the working hydroline 6 enters the rod cylinder chamber 7, thereby resulting in movement of the piston of the hydraulic cylinder 7 with the retraction of the rod. The working fluid from the piston cylinder cavity 7 working hydroline 5 through the control valve 4 and the drain hydroline 9 is supplied to the sensor 13 consumption and forth in the tank 10. The sensor 13 of the flow, as described above, there is a pressure drop, which is compressed spring device switching off the source of pressure or trouble signal and accordingly opens its contact 17. As a result, the electromagnetic relay 23 is not receiving power and remain open its contact 24 and the contact 27 of the electromagnetic relay 25, respectively, remains off the flow automatically adjusted depending on changes in the flow rate in the drain hydroline, determined by the flow of the working fluid in the piston or rod cylinder chamber.In the event of breakage of any of the hose 5, 6, 8 during operation of the hydraulic cylinder (pressed button 19 or 20) will result in loss of working fluid through the damaged area and accordingly the flow rate of the working fluid through the flow sensor 13 is less than the normal value. The pressure drop across the flow sensor in this case is insufficient to compress the spring device 17 and opening its contact. As a result, the power is supplied to the electromagnetic relay 23 closes its contact 24, and through him, power is supplied to the electromagnetic relay 25 closes its contact 27, the blocking relay 25 and including the lamp 26.Parallel to the lamp 26 (Fig. 2 is not shown) can be included buzzer sound alarm or the Executive element disconnects the source of power (for example, the electromagnet of the clutch on / off pump drive).After eliminating damage to the hydroline key 18 is opened, removing the self-locking solenoid relay 25, and the new circuit of the key 18 ensures the readiness of the control circuit (and thus the hydraulic system) for further work.In the right position of the valve 28 corresponding to the flow of the operating fluid in the rod cavity of the hydraulic cylinder 7, the microswitch 30 is not pressed, its contact is open, the electromagnet 15 is controlled throttle 16 is not powered on, the throttle 16 is in the left position and the flow sensor 13 is set to "large" design flow of the working fluid in the drain hydroline 9, corresponding to the mode retracting the hydraulic cylinder.The hydraulic system according to Fig. 4 differs from the hydraulic system according to Fig. 1 the valve 31 with the channel 32 of the control orifice 33, restricting the flow of working fluid from the pressure hydroline to said control channel 32 with the outlet 34. In addition, the system has a throttle 16 and the sensor 13 of the flow cavity 35 of the hydraulic management. Prov.W HY and accordingly the throttle 16 is right, required to control the mode of the extension rod of the hydraulic cylinder 7. In the right position of the valve 31 channel 32 is connected to the drain 10, the pressure in the outlet 34 is absent and the orifice 16 is located in the left position, necessary for the control mode retracting the hydraulic cylinder 7.In Fig. 5 shows the design of the sensor 13 consumption, conventionally shown in Fig. 1, 3, 4.The sensor has a housing 36 in which is located a throttling valve 37 and a spring 38, which forms with the housing a throttling hole 39. The hole 40 is supplied, and from the hole 41 is given to the working fluid. The hole 42 is used for drainage.In the absence of signal in the cavity 35 of the control throttling valve 37 under the action of the spring 38 holds the top position for the setting of the flow sensor "high" flow rate (corresponding to an open throttle 16 in Fig. 1, 3, 4). While supplying the signal to the cavity 35 of the control from the control channel 32 in Fig. 4 or from the pilot valve options Fig. 1, 3) throttling valve occupies a lower position (shown by the dotted line), corresponding to the configuration of the flow sensor at a smaller flow rate (corresponding to a closed throttle 16 in Fig. 1, 3, 4). Hydroglider with pressure and drain hose, the flow sensor is installed in the drain hydroline, the device switching off the source of pressure or trouble signal, the power supply circuit is set to the normally closed contact controlled from the mentioned flow sensor, wherein the flow sensor is made in the form of managed dip inductor, the minimum open position which corresponds to the flow of the working fluid in the piston cylinder chamber, and the maximum open position corresponds to the flow of the operating fluid in the rod cavity of the hydraulic cylinder.
FIELD: transport engineering; self-propelled wheeled vehicles.
SUBSTANCE: proposed vehicle contains frame 1 with cab 9, front and rear steerable wheels 4, 6 and middle wheels 5, engine placed behind the cab along vehicle and covered by hood 11. hydrostatic transmission contains pumping station 21 consisting of matching reduction gear driven by engine placed behind the cab, and three pumps connected by pipelines with hydraulic motors providing separate drives of wheels. Hydraulic motors are arranged along frame 1 between sidemembers on solid brackets made in form of boxes with flanges connected with wall of side member between its webs. Invention makes it possible to create ecologically clean and reliable multipurpose all-wheel-drive vehicle of high cross-country capacity with hydrostatic transmission to drive all wheels.
EFFECT: provision of convenient mounting and servicing of transmission units.
5 cl, 7 dwg