SU1082663A1 - Electrohydraulic steering system for a twin-engine vehicle - Google Patents

Abstract

1. ELECTRO-HYDRAULIC CONTROL SYSTEM OF DOUBLE-MOTOR VEHICLE, containing pressure sources of the working fluid, the inlets of which are connected to the reservoir of the working fluid, and the outlets - with hydraulic lines with the inputs of the first and second piston actuating hydraulic motors, respectively, the outlets of which are hydraulically connected to the switching device, each of which said hydraulic motors include a housing with a hollow piston disposed therein, in which they are made on the outer surface. . two cavities forming pressure, intermediate and drain cavities with the housing. and radial openings for communication between the intermediate and internal cavities, and a spring-loaded rod, with a manual control spool placed on it, and sensors for rotational speed of engines and movement of clutch pedals and gear levers, characterized in that, in order to increase reliability in operation, it is equipped with an electro-hydraulic crane. . consisting of a housing with a bore therein and a hole in which a plunger spring-loaded at one end is placed, the other end of which is provided with an actuator electrically connected with said sensors, and the switching device is designed as a spool-type hydraulic apparatus containing a sleeve with two radial grooves and with a hole in which the spool is spring-loaded at one end and forming an end cavity with the sleeve; at THOM, the outputs of the sources of pressure of the working fluid are connected with a hydraulic line The first cavity of the first hydraulic motor, the intermediate cavity of which is connected to the drain through the cavity formed by the first bore and the hole of the mentioned hydraulic apparatus, and through the cavity formed by the first hydraulic actuator, to the pressure cavity of the second hydraulic actuator, the intermediate cavity of which is connected to the drain through the cavities formed. the hole and groove of the electro-hydraulic crane, the drain of the second hydraulic actuator and the cavity, forming a second groove of said decoupler, .rabochey connected to a reservoir of liquid through a first cavity formed groove elekt1) 6gidravlicheskogo crane, and the second - directly. , 2. Electrohydraulic control system according to claim. 1, distinguishing from the fact that the plunger drive

Description

The electrohydraulic valve contains an electromagnet, the measles of which is kinematically connected to the said plunger end of the electrohydraulic crane by means of a pusher, and two clutch pedal displacement sensors are connected to two of the power supply circuits of the electromagnet winding, the third consecutively connected contacts located on said pusher and the body of the electrohydraulic crane and electric sensors for the rotational speed of the engines and the movement of the gear levers, and the fourth sensor for the gear levers edach.

FIELD OF THE INVENTION The invention relates to a transport engineering industry, namely, to electro-hydraulic control systems for twin-engine tracked tractors. The hydraulic control system of a twin-engine vehicle is known, containing pressure sources of the working fluid, whose inlets are connected to the working fluid reservoir and the outlets are connected to the inlets of the first and second piston actuating hydraulic motors, respectively, whose codes are hydraulically connected to the switching device, each of which Hydraulic motors include a housing with a hollow piston placed in it, in which the outside on the outer surface of the piston are two with pressure, intermediate and. drain cavities, and radial openings for connecting the intermediate and inner strips, and the spring-loaded stem with a manual control spool disposed on it, and sensors for the frequency of engine rotation and movement of the clutch pedal and gear levers C However, the hydraulic system is not known the required safety precautions as a result of insufficient reliability in operation, automatic prevention of the stopping of internal combustion engines from overload, automatic stopping of the machine when arbitrarily moving the shift lever to the neutral position on one of the power units. In addition, it does not provide automatic deceleration of both propellants, which is necessary in order to ensure safety, for example, when driving downhill. In this case, the vehicle with a sudden rupture of power flow to the propulsor of one installation and the automatic impact on the rotation mechanism of another installation can continue uncontrolled movement under the action of significant inertia forces due to its mass and deceleration. The purpose of the invention is to enhance reliability. This goal is achieved by the fact that a hydraulic control system containing pressure sources of the working fluid, whose inlets are connected to the working fluid reservoir and the outlets are connected to the inlets of the first and second piston actuators, respectively, whose outlets are hydraulically connected to the switching device, each of the above-mentioned hydraulic motors includes a housing with a hollow piston disposed therein, in which two surfaces are made on the outer surface forming a head with a pressure head The intermediate and internal cavities, the intermediate and internal cavities and the radial holes for the intermediate and internal cavities, and the spring-loaded brush with the manual control spool and the sensors for the frequency of engine rotation and the movement of clutch pedals and gear levers, are equipped with an electro-hydraulic valve consisting of housing with a groove and a hole in it, in which a plunger spring-loaded at one end is placed.

the other end of which is provided with an actuator electrically connected with said sensors, and the switching device is made in the form of a spool-type hydraulic apparatus containing a sleeve with two radial grooves and a hole in which the spool is spring-loaded from one end and forms a cavity with the sleeve. The source codes of the working fluid are connected by a hydroline to the pressure cavity of the first hydraulic actuator, the intermediate cavity of which is connected to the drain through the cavity, The first groove and aperture of the above hydraulic apparatus and through the cavity formed by the first groove 1; the hydraulic apparatus with the pressure cavity of the second hydraulic motor, the intermediate cavity of which is connected to the drain through the cavities formed by the hole and the hydraulic groove of the second hydraulic actuator and the cavity formed by the second groove of the above-mentioned guide of the device is connected to the reservoir of the working fluid, first through the cavity formed by electro tap point and the second directly.

In addition, the plunger drive of an electro-hydraulic crane contains an electromagnet, which is kinematically connected by means of a pusher to the terminal (a plunger of an electro-hydraulic crane, and two of the power circuits of the electromagnet winding include sensors for moving pedals of the clutch pedal, and in the third series there are connected contacts placed on the said chick pusher and body of an electro-hydraulic crane, and electric sensors for the frequency of rotation of the engines and the movement of gear shift levers, and the fourth - for tchiki gearshift lever.

FIG. 1 shows an electro-hydraulic diagram of the hydraulic control system of the vehicle in its initial position in FIG. 2 is a control scheme for clutch couplings; FIG. 3 is a diagram of connecting displacement sensors to gear shift sliders; Fig.4raarez aa in Fig., 3.

The system consists (Fig. 1) of two hydraulic pumps 1 and 2, the total flow rate of which working fluid enters the piston actuating hydraulic motors 3 and 4 with spools 5 and 6 of manual control, pistons 7 and 8, equipped with two rows of radial openings 9- 12, internal axial bores 13 and 14, and two sealing housings, forming pressure cylinders 15 and 16 in the cylinders, intermediate 17 and 18 and discharge cavities 19 and 2C. The spools are fastened on the belts 21 to 22 and returned to their original position by springs 23 and 24. For protection against overloads, the system contains a safety valve 25.

The pressure chamber 15 of the hydraulic engine 3 is constantly connected to the hydraulic pumps by a pipe 26. The intermediate cavity 17 through the bore 27 and 28 of the switching device 29 is connected to the drain cavity 19. The switching device 29 comprises a return spring 30 and a plunger 31, which forms an end cavity 32 with the sleeve, and a pipe 33 permanently connected to the intermediate cavity 18 of the hydraulic motor 4, as well as a bore 34, by a pipeline 35 which is permanently connected to the tank 36. In addition, the intermediate cavity 17 of the hydraulic motor 3 is continuously connected to the pressure cavity 16 of the hydraulic motor 4 via the bore 27 by the pipeline 37.

Intermediate cavity 18 of hydraulic engine 4 by pipe 38 through grooves 39 and 40 of an electro-hydraulic valve 41 is connected to a drain cavity 20, which through pipe 42 and groove 40 is permanently connected to the tank. The electro-hydraulic valve also contains a spring 43, a pair of electrical contacts 44 and a plunger 45, kinematically connected to the core (not shown) of the electromagnet 46 by means of a pusher 47 equipped with a washer 48 closing the electrical contacts 44..

The electromagnet 46 is connected to the tractor's on-board power network by four parallel electric circuits. The first and second electrical circuits each contain one permanently open displacement sensor 49 and 50 of the clutch pedals. The third circuit contains electrical contacts 44 connected in series, motor speed sensors 51 and 52, as well as constantly disconnected motion sensors 53 and 54 of the gear levers. The fourth electric circuit includes two series-connected permanently closed sensors moving 55 and 56 gear shift levers. The clutch pedals 57 and 58 (Fig. 2) are kinematically connected, respectively, with sensors 49-50, and also bars 59 and 60, containing slots 61 and 62, with hydraulic motors 3 and 4. Kinematic coupling of sensors 53 55 and 54, 56 (Fig. 3) with gearshifts 63 and 64 equipped with trapezoidal depressions 1 65 and 66, is carried out by swinging levers 67 and 68 pivotally mounted in the covers 69 and 70 of the gear changes and containing pins 71 and 72 with spherical heads . The hydraulic control system operates as follows. Consider the case where a twin-engine tractor is at rest when the engine is running. With the engine running steadily, when the crankshaft rotational speed of that shaft is critical, the contacts of the sensors 51 and 52 are closed. The clutch pedals 57 and 58 are released, so the contacts of the sensors 49 and 50 are open and the current through them cannot enter the electromagnet. The gear sliders are in the neutral position, in which the levers 67 and 68 under their own weight occupy the lower position, with the spherical heads of the pins 71 hours 72 resting against the bottom of the trapezoidal depressions. At the same time, there is a gap between the levers and the sensitive sensor elements, so that the contacts of the sensors 53 and 54 are open, and the contacts of the sensors 35 and 56 are closed. Consequently, the electromagnet is powered only by the fourth electrical circuit, which includes sensors 55 and 56. The lifting sypa of the electromagnet moves its measles, the pusher 47 and the plunger 45 to the initial (leftmost) position, compressing the spring 43. At the same time, the groove 39 connects the amp with the tank and the washer 4S closes the contacts 44. The manual control spools 5 and 6 with return springs 23 and 24, as well as the plunger 31 of the return spring 30, are held in the initial (rightmost) position. The working fluid from the hydraulic pumps enters the pressure cavity 15 of the hydraulic motor 3, passes through the radial bores 9 in the piston, the axial bore 13, the radial bores 10 and enters the intermediate cavity 17,., And from there through the bore 27 through the pipeline 37 - into the pressure cavity 16 the hydraulic motor 4. The drain cavity 19 through the grooves 28 and 27 is connected to the intermediate cavity 17. From the cavity 16 the working fluid through the radial holes 11 in the piston, the axial hole 14 and then through the second radial holes 12 passes into the intermediate cavity 18, and from its on line 38 and 38 and the groove 40 enters the tank. The drain cavity 20 through the groove 40 is always connected to the tank. Thus, the presence of sensors 55 and 56 ensures the parking of the vehicle with the engines running, as well as their independent start-up when the hydraulic power steering is disconnected, when the working fluid from the hydraulic pumps is freely drained into the hydraulic system. With manual control, you need to press, for example, the clutch pedal 57, to move the spool 21 spool, and with it the spool 5 itself to the left. In this case, the radial holes 9 in the piston intersect and the pressure in the cavity 15 increases, as long as the force exerted by this pressure on the piston. will not cause it to move. Since the piston is connected to the clutch and brake actuators, its movement will cause it to turn on or off. In the event of a spool stop, the piston will also stop when it reaches a certain position. In this manner, the position of the piston is determined by the position of the spool pin, i.e. there is tracking on movement. Manual control of a hydraulic engine with 4 or two stunters at the same time occurs as described. To start the tractor from the place, the clutches are pressed by pressing the pedals 57 and 58. At the same time, the contacts of sensors 49 and 50 are closed and the current feeds the electromagnet simultaneously on the first, second and fourth electrical circuits. Then the necessary gears are switched on at both power plants, for which, using shifting gears (not shown), the corresponding shifting rods 63 and 64 are moved. In this case, the pins 71 and 72, with spherical surfaces along inclined surfaces of the trapezoidal depressions 65 and 66, are raised upward those with the levers 67 and 68, the closure contacts the sensors 53 and 54 and opening the contact sensor 55 and valleys 56. The trapezoidal shape reduces the efforts on the gear change. In this position, the electromagnet is simultaneously fed by the first, second, and third electrical circuits and ensures that the plunger 45 of the electrohydraulic valve is held in the initial position. Therefore, when the pedals are gently released, the tractor starts moving away from the scene. The contacts of the sensors 49 and 50 open at the same time. When the tractor is moving, the electromagnet is powered only by the first electric circuit and the manual control of the hydraulic motors is carried out similarly to that described. If in the course of the movement a spontaneous movement of the gearshift lever to the neutral position occurs, a sudden stop of the engine or a decrease in the rotation frequency of its crankshaft below the critical one to any of the power units; the contact of the corresponding sensor 53 (54, 51 or 52) is opened with, the electromagnet is de-energized and the spring 43 moves the plunger. 45, the pusher 47 together with the washer 48 and the electromagnet core to the extreme right. At the same time, the contacts are 44 times. They are fed, and the plunger 45 cuts off the flow path 39 of the electro-hydraulic valve from the groove 40, i.e. shut off of the working fluid from the system. The pressure in the system rises until the safety valve 25 opens, through which 38 all the incoming working fluid flows into the tank. The increased pressure through the pipeline 33 is transferred to the end cavity 32 of the spool 29 and, compressing the spring 30, moves the plunger 3 I to the refusal to the left. The last cavity 17 from the cavity 19 of the hydraulic engine 3, simultaneously connecting the cavity 19 through the groove 34 with the tank. Since the increased pressure in the cavity 17 creates equal but opposite directed forces at the sealing ends, and in the cavity 15 the same forces act on the piston and body, the latter create an unbalance of the piston in the axial direction. For the same reason, the piston of the hydraulic engine 4 becomes unbalanced. Therefore, the pistons of both hydraulic engines automatically simultaneously move to the full to the left under the pressure of the adjustment of the safety valve. In this case, the clutches are turned off and both drives are braked. The clutch pedals 57 and 58 remain in the starting position due to the presence of slots 61 and 62 in the tie. If the automatic activation of the guide motors comes from a decrease in the engine crankshaft rotation frequency below critical due to overload, then when the clutch is turned off, the engine load will decrease and it will gain normal speed, the contacts of the corresponding rotation speed sensor will close, but there will be no spontaneous clutch engagement, so as in de-energizing the electromagnet, contacts 44 are opened and current cannot enter the electromagnet. This is the purpose of the electrical contacts 44. To move off, you need to press both clutch pedals. In this case, the contacts of the sensors 49 and 50 are closed and the current simultaneously on the first and second electrical circuit will begin to supply the electromagnet. The latter will move the plunger 45 to the initial position, in which the working fluid from the hydraulic pumps freely flows to the drain. With a smooth release of the pedal tractor moves away. Thus, the presence of displacement sensors 49 and 50 provides

the possibility of moving the tractor off.

When the gears are turned off and the clutch pedals are released, the electromagnet is powered by the fourth electric circuit including sensors 55 and 56. The electromagnet moves the plunger 45 to the initial position, opening the passage of the working fluid from the cavity 18 to the drain. Due to this, the pressure in the system drops, the safety valve closes, the plunger 31 of the switching device 29 under the action of the spring 30 also moves to its original position, blocking the passage of working fluid to the drain from the cavity 19 of the hydraulic motor 3 and at the same time assembling this cavity with the cavity 17, Jlopm and both hydraulic motors under As a result, the return springs move to the initial (rightmost) position, disengaging the tractor.

Thus, the proposed hydraulic system enhances driving safety and reliability of control of a twin-engine gantry tractor, as it provides automatic braking of both propellers in the event of a sudden loss of power flow to one and the same for any reason. In this case, additional controls are not required in the operator's cabin.

In addition, the proposed hydraulic system differs from the known higher efficiency due to the absence of constant throttling of the working fluid in it, as well as the static imbalance of the pistons of the hydraulic engines.

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Claims (2)

1. ELECTROHYDRAULIC CONTROL SYSTEM OF A TWO-MOTOR VEHICLE, containing sources of pressure of the working fluid, the inlets of which are connected to the reservoir of the working fluid, and the outputs are hydraulic lines with the inputs of the first and second piston actuating hydraulic motors, the outputs of which are hydraulically connected to the switching device, each of which is mentioned includes a housing with a hollow piston located in it, in which two girdles j forming with the housing are made on the outer surface m pressure, intermediate and drain cavities. and radial holes for connecting the intermediate and internal cavities, and a spring-loaded stem, with a manual control valve placed on it, and sensors for engine speed and pedal movement! clutch and gear shift lever, characterized in that, in order to increase reliability during operation, it is equipped with an electro-hydraulic crane ^ consisting of a housing with a groove made in it and an opening in which a plunger spring-loaded at one end is located, the other end of which is equipped with a drive, electrically connected with the said sensors, and the switching device is made in the form of a spool hydraulic device containing a sleeve with two radial grooves and with an opening in which a spring-loaded from one to the valve’s spool, forming an end cavity with the sleeve, and the outputs of the working fluid pressure sources • are connected by hydraulic lines to the pressure cavity of the first actuating hydraulic motor, the intermediate cavity of which is connected to the drain through the cavity formed by the first groove 'And the hole of the said hydraulic unit, and through the cavity formed' the first groove of the hydraulic unit — with the pressure cavity of the second actuating hydraulic motor, the intermediate cavity of which is connected to the drain through the cavities formed by with a hole and a groove of the electro-hydraulic crane, the drain meanness of the second actuating hydraulic motor and the cavity formed (the second groove of the hydraulic unit mentioned above, connected to the reservoir of the working fluid, the first through the cavity formed by the groove of the electro-hydraulic crane, and the second directly. ', 2. Electro-hydraulic control system pop. 1, disconnecting from me by the fact that □ plunger drive is about Ca5 of the electrohydraulic crane contains ¹ electromagnet, the anchor of which is kinematically connected via the pusher to the said end of the plunger of the electrohydraulic crane, and two of the power circuits of the winding of the electro- ⁵ magnet include clutch pedal displacement sensors, the third series-connected contacts placed on the said plunger and the body of the electro-hydraulic crane, and electric sensors of the frequency of rotation of the engines and movement of the gearshift levers, and in the fourth - the gearshift levers gears.