DE1059943B - Three-stage hydraulic drive for rail-moving track construction machines - Google Patents

Description

In recent years, in the course of mechanization the maintenance and renewal of the railway superstructure numerous work equipment that can be driven on rails and machines have been built. Some of these machines are available as two- or multi-axle vehicles equipped with its own axle drive. Combustion engines are primarily used as the power source. The power transmission to the running axles is partly purely mechanical, electrical or also hydraulic and pneumatic way. Due to the peculiarity of the superstructure with the gravel bedding thresholds inserted at certain intervals, it is often necessary to use the working machine To be able to drive up from threshold to threshold and stop at each time. In addition, this requires quick clearing of the construction site tracks for normal train traffic as well as the demand for the largest Mobility of the devices when driving from one construction site to another a line speed from at least 40 to 50 km / h.

There are known controls for mechanical power transmissions in which the ancestor of Threshold to threshold and the respective braking of the machine by a single hand or foot-operated Lever is effected. The single-lever controls emerged from the need for as simple a system as possible Operation of the undercarriage control so that the operating personnel can predominantly focus their attention can devote to the actual operation of the machine. Except for the single lever controls are at such machines then have additional control devices, for example for driving on a route for the speed adjustment of the engine, for the engine clutch, for the gear shift and the Brake.

In addition to the aforementioned drives with purely mechanical power transmission, those with hydraulic power transmission are known. The power source, usually an internal combustion engine, drives one or more oil pressure pumps, the pressurized delivery flow of which is converted into rotary motion in an oil motor. From there, the power is transmitted via suitable drive elements to the running axes of the machine. The hydraulic drives mentioned are partly single-stage, partly continuously adjustable, partly multi-stage. Of the latter, the previously known three-stage drives are constructed so that three oil pressure pumps, whose flow rate is controlled by separate control elements assigned to a pump, act on the drive oil motor with a flow rate corresponding to the output of the connected pumps. This arrangement makes a number of "Be" three-stage hydraulic drive units corresponding to the number of pumps used
for rail-moving track-laying machines

Applicant:

Rheiner machine factory

Windhoff Akt.-Ges.,
Rheine (Westphalia), Hovestr. 10

Franz Windhoff, Rheine (Westphalia),
has been named as the inventor

Control levers required, and an actuation for the brake must also be provided.

The advantage of using hydraulic travel drives in track construction machines lies essentially in the extensive fool safety by protecting all drive parts from overload when operating automatically Open the safety valves after reaching the maximum permissible hydraulic pressure System. Due to the fact that the work movements of these machines according to the current state of development are predominantly effected hydraulically, there are also hydraulic ones when they are used Travel drives in most cases significant simplifications and cheaper in the overall arrangement of the machines in that the oil pressure pumps required for the working hydraulics anyway can also be used for the drive hydraulics. Due to the fact that many times today semi-skilled workers are called in to operate the machines, it seems unavoidable In addition to being foolproof, there is also the greatest possible simplification of control and operation of the track laying machines. The previously known controls of multi-stage hydraulic travel drives are not satisfactory in this regard. The requirements outlined in practice are sufficient the new three-stage hydraulic drive for rail-moving track-laying machines according to the invention, in which only two oil pressure pumps with different delivery rates are provided, their oil flows either individually or both of them act on the oil motor, controlled by means of a manually operated step switch, which is connected to the supply line from the oil pressure pump to the

909 558/88

a foot-operated control slide through which the oil flow of this oil pressure pump is connected upstream either with the step switch or directly with the oil motor or a brake cylinder can be fed to the braking of the vehicle.

The drawing shows the hydraulic circuit diagram for such a travel drive.

Two oil pressure pumps 1 and 2 driven by an internal combustion engine with different delivery rates, of which pump 1 has the smaller and pump 2 the larger delivery rate, act on an oil motor 3 via several hydraulic regulating and control devices, which drives a vehicle axle via a suitable gearbox. A slide 4 makes it possible to selectively rotate the oil motor to the left or right and thus to choose the direction of travel. The slide 4 has three switch positions. In the middle position, the connections Pi and T 4 are connected, the connections Ai and 54 are blocked. The oil delivered by the pumps thus flows from the slide 4 directly back into the oil tank.

In the second position of the slide 4, the connections P4 are connected to Ai and 54 to T4. The pressurized oil enters the oil motor 3 (clockwise) and flows back into the oil tank.

In the third position of the slide 4, the connections P 4 are connected to 54 and Ai to Ti . The pressurized oil enters the oil motor 3 (left-hand rotation) and flows back into the oil tank.

By means of a step switch 5 with four switch positions, it is possible to selectively adjust the pressure oil flows of the Pump 1 or 2 separately or together to lead to the oil motor 3, so that as a result of the different Flow rates of pumps 1 and 2 can be achieved at three different speeds.

In the first switch position (standstill of the oil motor) the connections AS and B5 are blocked, while T5 and PS are connected to one another. The pressurized oil delivered by pumps 1 and 2 cannot flow through the step switch 5, but goes directly back to the oil tank via the pressure control and safety valves 6 or 7 or via the discharge valve 9 (see below).

In the second switch position (first slow speed step) the switch connections 55 are connected to T 5 and AS to P 5. When the control slide 8 (see below) is in the middle position, the pressure oil delivered by the pump 1 can flow unhindered via the step switch 5 and a check valve 12 into the supply line to the slide 4 (connection P 4) and from there to the oil motor 3. The pump 2 pumped oil flows pressureless through the step switch 5 back to the oil tank.

In the third position of the step switch 5 (second middle speed step) the connections AS are connected to TS and 55 to P 5. The pressurized oil conveyed by the pump 2 can now act on the oil motor 3, while the oil conveyed by the pump 1 flows back to the oil tank without pressure through the multiple switch 5.

In the fourth position of the step switch 5 (third largest speed step) the connections AS and 55 are connected to TS , while the connection PS is blocked. The delivery flows of the two pumps 1 and 2 can now reach the oil motor 3. With the help of the step switch 5, the vehicle is controlled when driving on a route, specifically the slide 4 and the step switch 5 are operated by hand.

Another foot-operated control slide 8 is installed in the pressure line between the oil pump 1 and the tap changer 5. This control slide is used on the one hand to advance the machine from threshold to threshold during work and on the other hand to actuate the brakes. The control slide 8 has three switching positions, namely an inner, middle and outer. In the middle position, the connections P 8 and TS are connected to one another, while the connections AS and 58 are blocked at the same time. The pressure oil conveyed by the pump 1 can thus flow unhindered through the control slide 8 to the step switch 5, connection 55. When the machine is traveling over a distance, the control slide 8 is in the middle position indicated above. A design is expediently selected for the control slide 8 in which the return to the central position from the two outer positions is automatically effected by spring force.

ao In the second, inner position of the control slide 8, the connections P 8 are connected to 5 8 and A 8 to T 8. The pressurized oil from pump 1 thus reaches the oil motor 3 via a check valve 11 and the slide 4.

During the transition from the inner to the third, outer position of the control slide 8, the lines between the control slide 8 and the oil motor 3 are depressurized. In the outer position of the control slide 8, the connections P 8 are connected to AS and 58 to TS . The pressure oil from the pump 1 passes through a discharge valve 10 and a pressure adjustment valve 13 to a brake cylinder 14, the piston of which passes through. Pressing the brake pads against the vehicle wheels actuates the vehicle brake 15.

The controllable pressure setting valve 13 is used to limit the braking force exerted by the brake cylinder 14 to a desired level. When the braking is initiated, the pressure oil can flow unhindered from the connection A1Z to the connection 513 in the brake cylinder 14. If the piston rod of the brake cylinder 14 is extended so far that the brake pad rests on the impeller of the machine, the connection T 13 on the pressure adjustment valve 13 opens at the selected brake pressure, and that is conveyed by pump 1 via the control slide 8 and the discharge valve 10 to the pressure adjustment valve 13 Oil can flow back to the oil tank via the connection T 13, while the oil pressure on the brake cylinder 14 and thus the braking force remain constant.

The unloading valve 10 arranged in the brake line upstream of the pressure adjustment valve 13 is used to release the brake 15. When braking is initiated with the control slide 8, free oil flow from port A 10 to B 10 is possible in the unloading valve 10. The connection TlO is blocked. If the supply line to the oil motor 3 between the check valves 11 and 12 and the slide 4 is put under oil pressure when the vehicle brake 15 is closed by actuating the control slide 8 (moving forward from threshold to threshold) or the step switch 5 (driving), oil pressure is obtained at the same time the control line 17 ending at connection SIO of the unloading valve 10, pressure which opens the connection TlO in the unloading valve 10. This creates a connection in the unloading valve 10 between the connections AlO, BIO and TlO, and the brake line between the control slide 8 and the brake cylinder 14 is depressurized by the oil flowing out to the oil tank via the connection TlO on the unloading valve 10. In this way, the spring 16 can the

Pull back the brake pad and the brake linkage including the piston rod of the brake cylinder 14 and thus release the vehicle brake 15.

From the context described above, it can be seen that the vehicle brake 15 is always automatically released as soon as pressure oil flows via the slide 4 to the oil motor 3 by actuating the step switch 5 or the control slide 8. On the other hand, after braking with the control slide 8, the vehicle remains braked until further travel is initiated with the step switch 5 or the control slide 8. It also remains braked when the control slide 8 moves back from the braking position by spring force into the central position, since the connection A 8 is blocked, which prevents the pressure oil contained in the brake cylinder 14 from flowing back. This is important for permanent way machines where the work tools transmit forces in the longitudinal direction to the vehicle. When working, the machine is prevented from being pushed away by the always closed brake with the arrangement described above. In addition, the brake remains applied when the vehicle is parked with the brakes and the drive motor is at a standstill, so that uncontrolled rolling is prevented.

A further discharge valve 9 is installed in the pressure oil line between the pressure setting valve 7 and the tap changer 5, in which the connections A 9 and B9 are always connected to one another for the free flow of pressurized oil to the tap changer 5. If the vehicle is now braked while driving on the road, when the step switch 5 is in the third or fourth position marked above, by actuating the control slide 8, the pressure generated in the brake line to the discharge valve 10 and pressure adjustment valve 13 is propagated to the am terminal S9 the unloader 9 ending control line 18 and causes the unloader 9 9. a compound of the terminal T9 to the terminals A9 and B at the same moment the entire zoom delivered by the pump 2 amount of oil 9 can flow without pressure to the oil tank via the terminal T9 of the unloader. The supply line to the oil motor 3 located behind the discharge valve 9 is depressurized and the oil motor 3 can no longer deliver any power.

From the above and from the description of the control slide 8 it can be seen that after Actuation of the control slide 8 for the purpose of braking the vehicle, regardless of the driving condition (Route travel or driving from threshold to threshold) it takes place, neither of the two oil pumps 1 and 2 can act on the oil motor 3. After braking has taken place, the brake 15 can only then be released if pressurized oil is fed into the supply line to the oil motor via the control slide 8 or the step switch 5 3 can reach.

All controls mentioned in the above description are manufactured by the relevant industry normal aggregates.

Claims (4)

Patent claims: ίο 1. Three-stage hydraulic drive for Rail-moving track-laying machines, characterized in that two oil pressure pumps (1, 2) with different delivery rates are provided, their oil flows either individually pressurize the oil motor (3) for yourself or both together, controlled by a manually operated one Step switch (5), the one in the supply line from the oil pressure pump (1) with the small delivery rate a foot-operated control slide (8) is connected upstream, through which the oil flow of this oil pressure pump (1) either with the step switch (5) or directly with the oil motor (3) or one Brake cylinder (14) can be supplied to brake the vehicle. 2. Travel drive according to claim 1, characterized in that that in the connecting line between the multiple switch (5) and the oil pressure pump (2) a hydraulically operated unloading valve (9) is arranged with the larger delivery rate is, which is automatically opened when the pressure in the brake cylinder (14) increases, so that when Applying the brake (15) the oil flow of the oil pressure pump (2) flows back to the oil tank without pressure via the unloading valve (9). 3. Travel drive according to claim 1 or 2, characterized in that the control slide (8) is designed is that the connecting line leading from it to the brake cylinder (14) when switched off of the oil flow acting on the brake cylinder (14) is shut off and thus a backflow of the pressure oil contained in the brake cylinder (14) is excluded. 4. Travel drive according to claim 1 or 3, characterized in that in the connecting line a hydraulically operated unloading valve between the control slide (8) and the brake cylinder (14) (10) is arranged, which is automatically opened when the pressure in the oil motor (3) increases, so that when the oil motor (3) is started, the pressure oil flows out of the brake cylinder (14) and thereby the vehicle brake (15) is released. Considered publications:
German patent specification No. 949 111. For this. 1 sheet of drawings