SU755627A1 - Control system for self-propelled machine gear box - Google Patents

Description

The invention relates to the transport industry, in particular to the management of friction clutches speed gearboxes of tractors and cars.

Known gearbox control system, comprising a valve, a connecting actuators friktsion- couplings GOVERNMENTAL ⁵ to the pump, a control valve, an overflow valve and the switch briefly reporting actuator clutch transmission with higher pump when the lowest gear ₁₀ when starting the self-propelled machine [1] .

However, such a system has a complex structure and control. The spool of the switch after disconnecting the high gear, additionally used when starting, must be fixed. Otherwise, in the process of gear shifting in the channel connecting the control valve with the distributor and communicating with the control cavity of the switch, a pressure drop causes the inevitable connection of the transmission, whose power cylinder is connected to the switch.

This connection leads to a decrease in the reliability of the towing friction elements 2

cops couplings. Before starting, it is necessary to release the spool latch, which increases the number of manipulations carried out by the driver during the intense stage of acceleration of the self-starting machine.

Also known is the control system of the transmission box of a self-propelled machine, which contains a pump connected by hydrolines to an overflow valve, a control valve and, by means of a distributor, to power cylinders of friction clutch transmissions, and a switch in the form of a spring-loaded spool mounted in the housing, with the groove in the latter connected by hydroline to the hydroline connecting the distributor to the high-power ram, and the control cavity on the side opposite to the spring-loaded one zu spool [2].

The disadvantage of such a control system is that the duration of the additional transmission connection is determined only by the volume of the dispenser. Since the slipping time of this clutch is not controlled, the work of friction increases,

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which reduces the reliability of the friction elements.

The purpose of the invention is to simplify the design, reduce the number of manipulations when starting the machine and increase reliability.

This goal is achieved by the fact that the proposed system is equipped with a hydroline connecting the control cavity of the switch with the hydroline connecting the distributor to the low-power ram. In addition, in the hydroline, communicating the groove of the switch housing with the hydroline connecting the distributor to the high-power ram, a check valve is installed.

FIG. 1 shows the position of the elements of the control system when the machine is stopped; in fig. 2 - the same, when starting off in two gears; in fig. 3 - the same, with the steady motion of the car in first gear.

The control system includes a pump 1, an overflow valve 2, a distributor 3 connected to power cylinders 4-6 of friction clutches of transmissions, respectively, first gear, second gear, third gear, a control valve, made in the form of a housing 7 and connected to the pedal 8 of the spool 9, having an axial bore 10, as well as a ball 11, springs 12 and 13, and a switch consisting of a spool 14 having an axial bore 15 in the front end connected to the bore 16, body 17 to the bore 18 and spring 19. The control valve housing 7 is connected hydroline 2 0 with a pump 1, a hydroline 21 - with a distributor 3, a hydroline 22 - with a drain hydroline 23. The control cavity 24 of the switch housing 17 is connected by a hydroline 25 with a hydroline 26 connecting the distributor 3 to the power cylinder 4 of the first-gear friction clutch, and the groove 18 - by hydroline 27 with a hydroline 28 connecting the distributor to the power cylinder 5 of the second gear. In hydroline 27 is installed a check valve 29.

With the pedal 8 depressed (Fig. 1), the spool 9 of the control valve occupies the leftmost position, cutting off the pump 1 from the distributor 3. At this position of the spool 9, the spring force 12 is minimal and the ball 11 opens the axial hole 10 through which the working fluid is from the purple cylinder 4 on the hydrolines 26, 21 and the hydrolines 22 falls into the drain hydroline

23. Thus, the friction clutch of the first gear is turned off.

When starting the machine, the distributor 3 (FIG. 2) is installed in the position of the first gear engaged. As the pedal 8 is released under the action of the spring 13, the spring 12 is compressed and the pressure line 20 communicates with the line 21. The working fluid begins to flow from the pump through

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the distributor 3 on the hydroline 26 to the power cylinder 4 of the first transmission and on the hydroline 25 to the control cavity 24 of the switch. Under the action of the spring 19, the valve 14 is in the leftmost position, in which the groove 18 of the body communicates through the groove 16 of the valve and the axial bore 15 with the control cavity. The working fluid from the groove 18 of the housing along the hydroline 27 enters the hydroline 28 and enters the power cylinder 5 of the second gear. There is a convergence and then compression of the friction elements of the couplings of the first and second gears. The pressure in the power cylinders, in the hydrolines 26 and 28, and also the hydrolines 25 and 27 increases. When reaching the value determined by the tightening of the spring 19, the spool 14 moves to the right, separating the power cylinder 5 of the second gear from the hydroline 25 (Fig. 3). The second gear is turned off, and the further acceleration of the car is carried out in first gear. In the power cylinder 4 of the first transmission, the pressure increases to a value determined by the bore valve 2.

When moving the car in first gear, the spool 14 is in the extreme right position. When the second gear is engaged, the distributor 3 communicates the power cylinder 5 of the second gear with hydraulic line 21, and the power cylinder of the first gear - with drain hydraulic line 23. The pressure in the control cavity 24 drops and the spool 14 moves to the extreme left position. The check valve 29 in the hydroline 27 eliminates the possibility of leaks from the power cylinder of the second transmission, cutting off the switch from the hydroline 28 under pressure.

When driving in third gear, the spool 14 is also in the leftmost position.

The invention increases the degree of automation of the gearbox, simplifies the design of the hydraulic system and reduces the intensity of the driver's work when manipulating the controls in the acceleration process of a self-propelled machine.

Claims (2)

Claim 1. The control system of the gearbox of a self-propelled machine, containing a pump connected by hydrolines with an overflow valve, a control valve and, through a distributor, with power cylinders of friction clutches of gears, and a switch in the form of a spring-loaded spool mounted in the housing, with the groove in the latter connected by hydroline to hydroline connecting the distributor to the high-power ram and the control cavity 755627 6 on the opposite side of the spring-loaded end of the spool, characterized in that, in order to simplify the design, reduce the number of manipulations when starting the machine and increase reliability, it is equipped with a hydraulic line connecting the control cavity of the switch with the hydraulic line connecting the distributor to the low-speed power cylinder. 2. Control system for π. 1, characterized in that in hydroline, telling a recess of the switch housing with a hydraulic line connecting the distributor to the high-pressure power cylinder is fitted with a check valve.