EP0487755B1 - Electrohydraulical gate control - Google Patents

Abstract

The invention relates to an electrohydraulic barrier drive having an electric motor (6) for driving a hydraulic pump (4), and a double-acting hydraulic cylinder (3) which is supplied with the hydraulic fluid and whose piston rod (3a) drives the barrier bar (1). To provide a simple and reliable control of the barrier drive, there is arranged between the hydraulic pump (4) and the hydraulic cylinder (3) a rotary sliding valve (5) which serves to control the upward and downward movement of the barrier bar (1) and also to prescribe a locking position and a position for an emergency closure in the event of energy failure. The rotary sliding valve (5) can be driven, by means of a stepping motor (7), against the force of a spring (10) which transfers the rotary sliding valve (5) into the emergency closing position.

Description

The invention relates to an electro-hydraulic barrier drive with an electric motor driving a hydraulic pump and a double-acting hydraulic cylinder to which the hydraulic fluid is applied, the piston rod of which drives a shaft carrying the barrier boom via a crank mechanism.

Such electro-hydraulic barrier drives are known. A control valve block with a plurality of valves is provided to control the up and down movement of the barrier boom and to determine a locking position and a position for an emergency closing in the event of a power failure. This control valve block, which comprises a large and complex holding magnet, is not only expensive to manufacture, but also requires high power consumption, since the holding magnet is always under voltage.

The invention has for its object to provide an electro-hydraulic barrier drive of the type described in the introduction simpler and therefore cheaper on the one hand and on the other hand to further develop such that the energy consumption for the electro-hydraulic barrier drive is significantly reduced.

The solution to this problem by the invention is characterized in that between the hydraulic pump and the hydraulic cylinder, a rotary valve for controlling the up and down movement of the barrier boom and for determining a Locking position and a position for an emergency closing in the event of a power failure is arranged, which can be driven by a stepper motor against the force of a spring which transfers the rotary valve into the emergency closing position.

The use of the rotary valve according to the invention not only eliminates the complex and expensive control valve block and holding magnet of the known barrier drive, but also results in a considerably lower energy consumption of the barrier drive according to the invention, because the holding force of the relatively small stepper motor is sufficient to close the rotary valve in the respectively activated position hold, so that the high energy consumption so far in the end positions of the barrier boom is avoided. The rotary valve according to the invention is simple and inexpensive to manufacture and results in a high degree of functional reliability, so that the measures required hitherto to monitor the respective position can also be considerably reduced.

In order to avoid one-sided loading of the rotary valve with hydraulic fluid and thereby one-sided pressing of the rotary valve in the rotary valve housing, which would result in increased resistance to rotation of the rotary valve using the stepping motor, according to a further feature of the invention, the part of the stepper motor that can be rotated Hydraulic fluid is always applied to the rotary valve from opposite sides. This action on both sides eliminates the pressure forces exerted on the rotatable part of the rotary valve; only a small force is required to turn the rotary valve, which can be applied by a small stepper motor.

In a preferred embodiment of the invention, the rotary valve is driven by and with a stepper motor Connection grooves provided rotating part and a housing part is formed, which is provided with connections for the pressure side of the hydraulic pump, for the cover-side and the piston rod-side working chamber of the hydraulic cylinder and for at least one line leading to the drip pan of the hydraulic pump and with openings opening in the cylindrical lateral surface between the housing part and the rotating part , which are arranged opposite each other in pairs, but offset from one another in the circumferential direction and / or axial direction. This configuration according to the invention results in a simple construction of the rotary valve.

If, according to a further feature of the invention, the openings are formed as radial bores in a hollow cylinder receiving the rotating part, which is provided on its outer circumferential surface with annular grooves connecting the openings that belong together in pairs and is in turn inserted non-rotatably into the housing part having the connections, the rotary slide valve according to the invention forms one Kind of hydraulic block, which prevents the occurrence of leaks with simplified production.

In a preferred embodiment, all of the openings are arranged in an axial plane of the housing part or of the hollow cylinder and the connecting grooves are axially parallel, but offset in the circumferential direction from one another in the rotating part. In this way, the connections, bores, ring grooves and connecting grooves can be produced in a particularly simple manner.

In order to avoid complex monitoring devices for the respective position detection of the rotating part, according to a further feature of the invention, the rotating part can be rotated by an angle of less than 180 ° between two stops, the rotating part being in the end position in the emergency closing position and the other in the spring-caused position End position in the position causing the upward movement of the barrier boom.

In a further development according to the invention, the rotating part can be transferred into a locking position between the upward movement and the downward movement of the barrier boom, in which the openings connected to the piston rod-side working space of the hydraulic cylinder are closed by spring-loaded sealing bodies which are arranged in a transverse bore in the rotating part . As a result, in this locking position, in which the barrier boom is in the vertical opening position, the gap between the rotating part and the housing part is reduced to almost zero; this avoids leakage losses in this end position of the barrier boom, in which the barrier boom remains for the longest time. There is therefore no constant provision of energy to ensure that the barrier boom remains open.

If the barrier drive is equipped with a push-off spring, which loads the barrier boom in its open position in the sense of a movement, so that it also comes out of its vertical dead center position in the event of a power failure, the invention proposes the force related to the area of the openings Form spring loaded sealing body greater than the force of the pull-off spring related to the same area. This configuration prevents the spring-loaded sealing bodies in the rotating part of the rotary valve from being pushed back by the pressure in the hydraulic fluid prevailing in the control bores, which pressure is formed in the hydraulic fluid due to the pressure spring acting on the barrier boom.

So that the barrier boom is not transferred at an impermissibly high speed from its vertical open position into its horizontal closed position when the rotary valve is moved to the emergency closing position in the event of a power failure, is according to a further feature of the invention in the piston rod side Working space of the hydraulic cylinder with the collecting tub in the emergency closing position connecting line a throttle to limit the movement of the barrier boom. According to the invention, this throttle is formed by a throttle screw between the corresponding ring grooves in the hollow cylinder.

In order to prevent the rotary part of the rotary slide from being pulled obliquely by the spring which loads it in the direction of the emergency closing position, this spring is formed according to the invention by two spiral springs acting on opposite sides of the rotary part. In this way, one-sided loading of the rotating part by the spring force exerted on it is also excluded.

Finally, with the invention it is proposed to check the function of the spring transferring the rotary valve into the emergency closing position by switching off the power to the stepping motor when the barrier boom is in the closed position and the pulses resulting from the rotary movement of the rotating part into the emergency closing position in the stepping motor acting as a generator be evaluated. If no impulses occur during such an evaluation, this means that the rotating part of the rotary valve has not been moved from the position corresponding to the closed position of the barrier boom into the emergency closed position. In this case it can be assumed that the spring loading the rotating part is either blocked or defective. If the distance between the individual pulses is too great during the upper test, it can be assumed that the spring is either partially blocked or is too weak due to other malfunctions. A properly acting spring can only be assumed if a complete pulse sequence with the correct pulse spacing results. In the manner described above, it is always possible in the simplest way to ensure the functionality of the rotary slide valve with regard to the intended emergency closing position to be checked when the barrier boom is in its horizontal closed position.

• Fig. 1 eine schematische Gesamtdarstellung des elektrohydraulischen Schrankenantriebes,
• Fig. 2 einen Längsschnitt durch den zugehörigen Drehschieben,
• Fig. 3a-3d Draufsichten auf den Drehschieber mit in vier unterschiedlichen Stellungen befindlichem Drehteil,
• Fig. 4 einen Schnitt durch den oberen Teil des Drehschiebers gemäß der Schnittlinie IV - IV in Fig. 3d und
• Fig. 5 einen Querschnitt durch den Drehschieber gemäß der Schnittlinie V - V in Fig. 2.

An exemplary embodiment of the barrier drive according to the invention is shown in the drawing, namely:

• 1 is a schematic overall representation of the electro-hydraulic barrier drive,
• 2 shows a longitudinal section through the associated rotary slide,
• 3a-3d plan views of the rotary slide valve with the rotating part located in four different positions,
• Fig. 4 shows a section through the upper part of the rotary valve according to the section line IV - IV in Fig. 3d and
• 5 shows a cross section through the rotary slide valve along the section line V - V in FIG. 2.

The electrohydraulic drive shown schematically in FIG. 1 serves to move a barrier boom 1 up and down, which in the schematic illustration can be driven by a piston rod 3b of a hydraulic cylinder 3 about a fixed axis 2. This hydraulic cylinder 3 is a double-acting cylinder, the piston 3a of which can optionally be acted upon on one of the two sides with hydraulic fluid. The hydraulic cylinder 3 thus contains a working chamber 3c on the piston rod side and a working chamber 3d on the cover side. In Fig. 1 it is also shown that the hydraulic cylinder 3 can perform a pivoting movement about a bearing axis 3e to the circular arc-shaped movement of the pivot pin 3f between Follow piston rod 3b and barrier boom 1 when the barrier boom 1 is moved up and down. In the praix, a crank mechanism is used instead of the basic illustration in FIG. 1, which transmits the axial movement of the piston rod 3b to a shaft carrying the barrier boom.

The piston 3a of the hydraulic cylinder 3 is driven by a hydraulic fluid which is supplied by a hydraulic pump 4 either to the piston rod-side or the cover-side working space 3c or 3d with the aid of a rotary slide valve 5, which is only indicated schematically in FIG. 1, but based on an exemplary embodiment 2 to 5 is shown. While the hydraulic pump 4 is driven by an electric motor 6, the rotary valve 5 is driven by a stepper motor 7. Both motors 6 and 7 are controlled by control electronics 8 by a driver 6a and 7a.

In Fig. 1 it can finally be seen that the hydraulic fluid is withdrawn from the hydraulic pump 4 of a sump 9 and that the movable part of the rotary valve 5 is under the force of a spring 10 which is designed as a spiral spring. Finally, a control valve 11 can be seen in Fig. 1, which can be operated by hand, e.g. to be able to determine the barrier boom in any position during maintenance work.

The rotary valve 5 shown in FIGS. 2 to 5 using an exemplary embodiment consists of a cuboid housing part 13 in which a hollow cylinder 14 is arranged non-rotatably, in which in turn the rotary part 15 of the rotary valve 5 which can be driven by the stepping motor 7 is rotatably but axially immovably mounted . At the top, the housing part 13 is closed by a cover 16 in the region of the opening receiving the hollow cylinder 14 and the rotating part 15; 4, the stepping motor 7 is connected to the rotary part 15 through this cover 16.

According to FIG. 2, four connections are formed in the housing part 13 of the rotary valve 5. The connection 17 is connected by a line to the working chamber 3c on the piston rod side and the connection 18 is connected by a line to the working chamber 3d of the hydraulic cylinder 3 on the cover side. On the side opposite these two connections 17 and 18, the housing part is provided with two connections 19 lying one above the other, which lead to the collecting trough 9 of the hydraulic pump 4. On the rear side in FIG. 2, the housing part 13 finally has a connection 20 which is connected to the pressure side of the hydraulic pump 4. These connections 17 to 20 are also shown in the diagram of FIG. 1.

As can again be seen in FIG. 2, each of these connections 17 to 20 is connected to an annular groove 21 which are formed on the outside of the hollow cylinder 14 and which in turn open out with opposite radial bores 22 in the inner cylindrical lateral surface of the hollow cylinder 14. In this way, the connections 17 to 20 are each connected to two openings, which lie opposite one another with respect to the rotating part 15 rotatably mounted in the hollow cylinder 14, so that pressures which load the rotating part 15 and cancel each other out in these openings, thereby eliminating one-sided loads on the rotating part 15 be avoided.

The rotating part 15 is provided on its cylindrical outer surface with six pairs of mutually opposite connecting grooves 23a, 23b, 24a, 24b, 25a and 25b, of which the connecting grooves 23a and 23b or 24a and 24b or 25a and 25b are located one behind the other in the axial direction. The connecting grooves 23a, 24a and 25a or 23b, 24b and 25b are adjacent to one another in the circumferential direction according to FIG. 5. For the sake of better illustration, the rotating part 15 is drawn in a different position in FIG. 2 than in FIG. 5.

If the barrier boom 1 is to be brought into its vertical open position by movement, the rotary part 15 of the rotary slide 5 is brought into a position by means of the stepping motor 7, which is shown in FIG. 3d. In this position, the connecting grooves 23a connect the connection 2o connected to the pressure side of the hydraulic pump 4 to the connection 17, which leads to the working chamber 3c of the hydraulic cylinder 3 on the piston rod side. In this position of the rotary slide valve 5, the hydraulic fluid supplied by the hydraulic pump 4 presses into the piston 3a in the direction of the bearing axis 3e, so that the barrier boom 1 is moved into its vertical open position. The hydraulic fluid present in the cover-side working space 3d of the hydraulic cylinder 3 can reach the lower connection 19 via the connection 18, the associated annular groove 21 together with radial bores 22 and the connecting grooves 23b, which leads to the collecting trough 9.

In order to transfer the barrier boom from its open position into its horizontal closed position, the rotating part 15 of the rotary slide 5 is rotated into the position shown in FIG. 3b with the aid of the stepping motor 7. In this position, the connection 20 coming from the pressure side of the hydraulic pump 4 is connected via the connecting grooves 25b to the connection 18, which leads to the cover-side working space 3d of the hydraulic cylinder 3. As a result, hydraulic fluid reaches the underside of the piston 3a, so that it is displaced while the barrier boom 1 is being moved away. The hydraulic fluid present in the working chamber 3c on the piston rod side can reach the collecting trough 9 via the connecting groove 25a and the upper connection 19.

In order to transfer the barrier boom 1 into its horizontal closed position by a kind of emergency closure in the event of a power failure, it is loaded in the closing direction with a push-off spring 26 which in 1 is drawn inside the cover-side working space 3d. This emergency closure is brought about by the fact that the rotary part 15 of the rotary slide 5 according to FIG. 1 is loaded by a spring 10, which transfers it to the position shown in FIG. 3a if the stepping motor 7 fails. In this position of the rotating part 15, the cover-side working space 3d is connected via the connection 18 and the connecting grooves 24b to the lower connection 19 leading to the collecting trough 9. At the same time, the connection 17 which is connected to the working chamber 3c on the piston rod side is connected to the annular groove 21a via the connecting grooves 24a and via the radial bores 22a. As is apparent from FIG. 4, this annular groove 21a is connected to the overlying annular groove 21 connected to the upper connection 19 by a throttle, which is formed by a throttle screw 27 screwed axially into the hollow cylinder 14. The hydraulic fluid emerging from the piston rod-side working space 3c in the event of an emergency closure can be throttled in this way, so that a too rapid downward movement of the barrier boom 1 is prevented. By turning the throttle screw 27, the speed of the downward movement of the barrier boom 1 can be adjusted in a simple manner.

As FIGS. 3a, 3b, 3c and 3d show, the rotating part 15 can be rotated through an angle below 180 ° in the hollow cylinder 14, the end positions being limited in each case by stops 28a and 28b, against which a stop pin 29 of the rotating part 15 abuts is coming. The starting position here forms the emergency closing position shown in FIG. 3a, in which the stop pin 29 is pulled by the spring 10 against the stop 28a. Starting from this emergency closing position, the above-described closed position is reached after 25.2 ° rotation according to FIG. 3b, in which the barrier boom 1 is in its horizontal position. The opening position of the also described Barrier boom 1 results from a rotation of the rotating part 15 according to FIG. 3d by 154.8 °. In this position, the stop pin 29 bears against the stop 28b of the hollow cylinder 14.

In order to prevent that a high expenditure of energy is required to keep the barrier boom 1 in its end positions, in particular in the open position, a locking position is provided, which is shown in Fig. 3c and between the open position shown in FIG. 3d and the closed position 3b lies after a rotation of the rotating part 15 by 90 °. In this locking position, the radial bores 22 leading to the connection 17 are closed by sealing bodies 30 which are arranged in recesses in the rotating part 15 and are loaded by a spring 31 arranged in a transverse bore. This ensures that in the open position of the barrier boom 1, no hydraulic fluid can escape from the piston rod-side working space 3c of the hydraulic cylinder 3, so that there is no need for a constant supply of hydraulic fluid due to leakage losses. The force of the spring 31 loading the sealing body 30, based on the area of the openings of the radial bores 22 according to FIG. 5, is chosen to be greater than the force of the push-off spring 26 relating to the same surface, which loads the barrier boom 1 in its open position in the sense of a movement.

In order to check the functionality of the spring 10 which transfers the rotating part 15 of the rotary slide 5 into the emergency closing position, the stepping motor 7 can be switched off in a position according to FIG. 3b, in which the barrier boom 1 is in the closed position. The pulses generated by the spring 10 caused by the rotary movement of the rotating part 15 into the position according to FIG. 3a in the stepping motor 7, which now acts as a generator, can be evaluated. If no pulses occur, the spring 10 is defective. The corresponding results Pulse train with a short pulse interval, the spring 10 is in order. If there is a pulse train, but with a larger pulse spacing, it can be assumed that the spring 10 is either blocked or one of these springs is defective when, for example, 2 coil springs are used as the spring 10. The design described above thus enables a simple check of the spring 10, which is important for the emergency closing position.

Reference symbol list:

Claims (12)

1. An electro-hydraulic barrier drive, comprising an electric motor (6) driving a hydraulic pump (4), and a double-acting hydraulic cylinder (3) which is subjected to the action of hydraulic fluid and the piston rod (3b) of which drives by way of a crank drive a shaft carrying the barrier boom (1), characterised in that a rotary slide valve (5) is disposed between the hydraulic pump (4) and the hydraulic cylinder (3) to control the up and down movement of the barrier boom (1), and for locating a locking position and a position for emergency closure in the event of a power failure, said valve being drivable by a stepping motor (7) in opposition to the force of a spring (10) which moves the rotary slide valve (5) into the emergency closure position.
2. A barrier drive according to claim 1, characterised in that that part (15a) of the rotary slide valve (5) which can be turned by the stepping motor (7) is always subjected to the action of hydraulic fluid from opposite sides.
3. A barrier drive according to claims 1 and 2, characterised in that the rotary slide valve (5) is formed on the one hand by a rotary part (15) drivable by the stepping motor (7) and provided with connecting grooves (23a, 23b, 24a, 24b, 25a, 25b) and on the other hand by a housing part (13) which is provided with connections (17, 18, 19, 20) for the delivery side of the hydraulic pump (4), for the working space (3d, 3e) of the hydraulic cylinder (3) on the cover side and on the piston rod side, and for at least one line leading to the sump (9) of the hydraulic pump (4), and with apertures (22, 22a) leading into the cylindrical outer surface between the housing part (13) and the rotary part (15), said apertures being disposed opposite one another in pairs but in offset relationship circumferentially and/or axially.
4. A barrier drive according to claim 3, characterised in that the apertures are formed as radial bores (22, 22a) in a hollow cylinder (14) receiving the rotary part (15), said hollow cylinder being provided with annular grooves (21) on its outer surface, said annular grooves communicating with the associated pairs of radial bores (22, 22a), said hollow cylinder in turn being inserted so as to be relatively non-rotatable in the housing part (13) provided with the connections (17, 18, 19, 20).
5. A barrier drive according to claim 3 or 4, characterised in that all the apertures (22, 22a) are disposed in an axial plane of the housing (13) and hollow cylinder (14) and the connecting grooves (23a, 23b, 24a, 24b, 25a, 25b) are formed in axis-parallel relationship but circumferentially offset relationship in the rotary part (15).
6. A barrier drive according to at least one of claims 1 to 5, characterised in that the rotary part (15) is rotatable through an angle of less than 180° between two stops (22a, 22b), the rotary part (15) in one end position produced by the spring (10) being in the emergency closure position while in the other end position it is in the position which causes the barrier boom (1) to be lifted.
7. A barrier drive according to at least one of claims 1 to 6, characterised in that the rotary part (15) can be moved into a locking position situated between the position producing the lifting movement and the position producing the downward movement of the barrier boom (1), in which locking position the openings (22) connected to the working space (3c) of the hydraulic cylinder (3) on the piston rod side are closed by spring-loaded sealing elements (30) disposed in a transverse bore in the rotary part (15).
8. A barrier drive according to claim 7y, characterised in that the force of the spring (31) loading the sealing elements (30) as considered in relation to the area of the apertures (22) is larger than the force - in relation to the same area - of a push-back spring (26) which loads the barrier boom (1) in the direction of a downward movement when the boom is in its open position.
9. A barrier drive according to at least one of claims 1 to 8, characterised in that a restrictor for limiting the downward movement of the barrier boom (1) is disposed in the line which in the emergency closure position connects the working space (3c) of the hydraulic cylinder (3) on the piston rod side to the sump (9).
10. A barrier drive according to claim 9, characterised in that the restrictor is formed by a throttle screw (27) between the corresponding annular grooves (21, 21a) in the hollow cylinder (14).
11. A barrier drive according to at least one of claims 1 to 10, characterised in that the spring (10) moving the rotary slide valve (5) into the emergency closure position is formed by two coil springs acting on opposite sides of the rotary part (15).
12. A barrier drive according to claim 1 or 11, characterised in that the function of the spring (10) moving the rotary slide valve (5) into the emergency closure position can be checked by disconnecting the current to the stepping motor (7) with the barrier boom (1) in the closed position and evaluating the pulses produced in the stepping motor (7) acting as a generator by the rotary movement of the rotary part (15) into the emergency closure position.

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