DE102012011498A1 - Differential cylinder arrangement for a hydromechanical drive for electric circuit breakers - Google Patents

Abstract

The invention relates to a differential cylinder arrangement (1) for a hydromechanical drive for actuating an electrical switch, in particular a high-voltage switch, comprising a first pressure region (3) for applying a system pressure (p1); a second pressure area (4, 5); a movable in a movement range piston (2) which is movable in response to a pressure difference between the first and the second pressure region (3, 4, 5); a damping device, which provides a damping against the movement of the piston (2) during a movement of the piston (2) in the direction of the second pressure region (4, 5), wherein the damping automatically sets, and the damping device to a damping chamber (11) an end of the second pressure area (4) opposite the piston (2) and a damping pin (10) protruding toward the second pressure area on the piston (2), the damping pin (10) and the damping chamber (11) being formed in that the damping pin (10) projects into the damping chamber (11) in a movement range and thus separates the second pressure region (4, 5) from the damping chamber (11). The damping device has a damping bushing (12), in the interior of which the damping chamber (11) forms a third pressure region which can be closed by at least one movable closure element (15) and the movable closure element (15) interacting with the damping chamber (11) Movement of the piston (2) by means of a contact pressure of at least one cooperating plate spring (17) is movable.

Description

The invention relates to hydraulic differential cylinder arrangement for hydromechanical drives for electrical circuit breakers.

Hydromechanical spring accumulator drives usually have differential cylinders. A piston of the differential cylinder is connected to a piston rod which is movable by pressurizing a pressure volume. Furthermore, the piston rod is connected to an electrical power switch, so that by moving the piston rod of the electric power switch can be switched. For example, to open the electrical circuit breaker, the pressure volume of the differential cylinder can be acted upon by a hydraulic pressure, so that the piston rod moves in a corresponding position.

The pressure in the printing volume is usually provided by a printing cylinder which is coupled to a mechanical energy storage, such as a spring assembly. If the circuit breaker to be switched, the spring force is released to the pressure cylinder, so that there builds a working or system pressure, which is present via a hydraulic connection in the pressure volume of the differential cylinder. The working pressure in the pressure range moves the piston and the piston rod of the differential cylinder.

If the mechanical energy store is formed on the pressure cylinder as a spring arrangement, this is usually applied to provide a sufficient force with a bias voltage. Upon release of the spring assembly, the working pressure builds up very quickly, so that the pressure range of the differential cylinder is applied almost directly to the working pressure. As a result, the piston of the differential cylinder is moved with a high acceleration force in the direction of an end stop. To protect the differential cylinder and the other mechanical components coupled therewith, therefore, a cushioning is often provided in which the speed of the piston is reduced before this or another component strikes against a stop. The damping is intended to cause the final speed of the piston is brought below a predetermined threshold when striking, in order to avoid damage to the components.

Depending on the application and the type of circuit breaker to be switched, the tripping speed, the working pressure provided and the like, a separate geometric design of the damping must be carried out individually for each application. As a result, the hydromechanical spring-loaded drives are already set at the beginning of production to a specific application. A change in the scope is usually no longer possible after their production. This makes the production of hydromechanical spring storage drives inflexible, since they can only be made specifically for a particular application and it is not possible to produce for a number of indefinite applications on stock and adapt after their preparation to the given application.

It is therefore desirable to provide a hydromechanical spring accumulator drive which has an end position damping which can be decelerated regardless of the working pressure provided by the mechanical energy accumulator and regardless of the mass moved with the piston rod so as to reach a final speed of the piston rod below a predetermined threshold, before the piston, the piston rod or an associated component strikes against an end stop.

It is therefore an object of the present invention to provide a hydromechanical drive for actuating an electric circuit breaker, in particular a high-voltage circuit breaker, in which the level of the end position damping is regulated.

This object is achieved by a differential cylinder arrangement for a hydromechanical drive for actuating an electric circuit breaker according to claim 1 and by the hydromechanical drive according to claim 9.

Further advantageous embodiments of the present invention are specified in the dependent claims.

According to a first aspect, a differential cylinder arrangement for a hydromechanical drive for actuating an electrical switch, in particular a high-voltage switch, is provided.

• – einen ersten Druckbereich zum Beaufschlagen mit einem Arbeits- oder Systemdruck;
• – einen zweiten Druckbereich;
• – einen in einem Bewegungsbereich beweglichen Kolben, der abhängig von einer Druckdifferenz zwischen dem ersten und dem zweiten Druckbereich bewegbar ist;

The differential cylinder assembly includes:

• - A first pressure range for applying a working or system pressure;
• A second pressure area;
• A movable piston in a range of movement movable in response to a pressure difference between the first and second pressure ranges;

wherein a damping device is provided which, upon movement of the piston in the direction of the second pressure region, a damping, Also called end position damping, provides against the movement of the piston, wherein the damping automatically adjusts, and the damping device has a damping chamber at a piston opposite end of the second pressure region and a protruding on the piston in the direction of the second pressure region cylindrical, in particular circular cylindrical, damping pin wherein the damping pin and the damping chamber are formed so that the damping pin protrudes in a movement range in the damping chamber and thus separates the second pressure range from the damping chamber.

It can thereby be achieved that in a first portion of the range of movement of the piston no appreciable damping is caused. Only in a second portion of the movement range, when the damping pin passes through the movement of the piston in a damping chamber, the fluid contained in the damping chamber is enclosed, so that it can flow out of the damping chamber only by a reduced passage cross-section. As a result, the damping against the movement of the piston in the first piston area is significantly increased.

The damping device comprises a damping bush, in the interior of which the damping chamber forms a third pressure region, which can be closed by at least one movable closure element. The movable with the damping chamber cooperating closure element is movable during a movement of the piston by means of a contact pressure of at least one cooperating plate spring. In an advantageous embodiment, three parts which are movable in the axial direction, in particular closure pins, are provided as closure elements.

The damping chamber and the second pressure region are connectable via at least one hydraulic line with a hydraulic fluid container, for example by means of a 3/2-way seat valve.

One idea of the above hydrostatic-mechanical differential cylinder assembly is to provide damping of movement of the piston in a portion (portion) of the range of movement of the piston to reduce the speed of the piston prior to reaching an end stop.

By providing an automatically adjustable damping, it is possible, the differential cylinder assembly, hereinafter also referred to as a differential cylinder, regardless of the knowledge of the later system in which it is used to form.

In this way, a largely application-neutral production of such hydromechanical drives is possible, which can be done without knowledge of the final application.

According to the present invention, the cross section through which the hydraulic fluid can flow out of the damping chamber, automatically, so that the hydromechanical drive to the application, ie. H. on the output speed of the piston, the force acting on the piston, the maximum speed of the piston and the mass of the elements connected to the piston rod, without external interference is adjusted to achieve the desired switching behavior of the actuated with the hydromechanical drive circuit breaker.

For this purpose, the damping pin and the damping chamber are formed so that after the penetration of the damping pin in the damping chamber remains a residual gap having a predetermined passage cross-section.

In particular, the predetermined passage cross-section can be chosen so that this causes a predetermined maximum damping against the movement of the piston.

After an entry of the damping pin into the damping chamber, the third pressure region experiences a separation from the second pressure region through the damping pin. The hydraulic fluid initially flows only through the residual gap in the second pressure range and then back into the hydraulic fluid reservoir, wherein the damping pressure resulting from this congestion in the third pressure range brakes the differential piston.

The closure element moves away with its guide from the bottom of the damping bushing, as soon as the damping pressure in the third pressure range exerts a greater force on the closure element than the contact force of the provided cup springs and an additional connection between the third pressure region and the second pressure region is formed, through which Hydraulic fluid flows in the third pressure range.

The closure element again presses against the bottom of the damping bushing as soon as the damping pressure in the third pressure region decreases again and the contact force of the disk springs exceeds the pressure force exerted on the closure element and the additional connection between the third pressure region and the second pressure region closes again, as a result height the pressure in the third pressure range controls and thus the braking effect on the differential piston.

The movable closure element thus advantageously controls the damping pressure.

The pressure at which the hydraulic force on the closure element (pressure times effective area) is equal to the closing spring force and therefore opens the closure element is referred to as the opening pressure and is determined by the ratio of the force of the disc springs used to the effective surface of the closure element. The active surface is the acted upon by the damping pressure circular area of the closure element within the contact and sealing point between the closure element and damping bushing.

According to a further aspect, a hydromechanical drive is provided with the above differential cylinder, which is preferably used in high-voltage circuit breakers.

A preferred embodiment of the present invention will be explained in more detail with reference to the accompanying drawings. It shows:

1 a schematic cross-sectional view through a hydraulic differential cylinder with a cushioning according to a preferred embodiment.

1 shows a schematic cross-sectional view of a hydraulic differential cylinder 1 with a piston 2 , the first printing area 3 from a second pressure area 4 . 5 separates. The piston 2 is movably arranged in a cylinder interior, wherein the piston 2 the first and the second pressure range 3 . 4 . 5 hermetically separated from each other. The first printing area 3 is acted upon by a working or system pressure p1.

The working pressure p1 may be provided, for example, by a separate pressure cylinder (not shown) that relies on a piston by releasing a mechanical energy accumulator, such as a biased plate or coil spring 2 the printing cylinder can be effected.

The hydraulic differential cylinder 1 serves to provide a triggering movement. This is the piston 2 of the differential cylinder 1 with a piston rod 6 connected, which causes as an actuator directly or indirectly opening or closing, for example, an electrical high voltage or medium voltage circuit breaker.

Upon application of the working pressure p1 in the first pressure range 3 the piston moves 2 according to the pressure difference between the first and second pressure ranges 3 . 4 . 5 so that the volume of the second pressure range 4 . 5 reduced, with one in the second pressure range 4 . 5 located hydraulic fluid via a designated hydraulic line 7 flows directly or indirectly into a hydraulic fluid reservoir (not shown) and therefore no significant back pressure on the piston 2 exercises. The hydraulic line 7 is preferably connected via a 3/2-Wegevewntil with a hydraulic fluid reservoir.

When triggering the hydromechanical drive, the piston 2 of the differential cylinder 1 accelerated, the second pressure range 4 . 5 not essential to reducing the speed of the piston 2 contributes. In this way, a switching operation carried out with the aid of the hydromechanical drive can be carried out at a desired speed, so that fast tripping operations are possible.

It should be avoided that accelerated by the triggering piston 2 of the differential cylinder 1 or an associated component strikes unbraked at an end stop, as this can be damaged and also disturbing noises may occur. For this reason, a cushioning is provided. For the cushioning of the hydraulic differential cylinder 1 with a cylindrical, in particular circular cylindrical, damping pin 10 equipped during a movement of the piston 2 a damping of the movement of the piston 2 causes. For this purpose, a damping bush according to the invention 12 , in whose interior a damping chamber 11 or a third pressure region is formed, and cooperating, preferably designed as a closure pin closure elements 15 and one or more disc springs 17 provided, wherein the one or more locking pin 15 by means of a contact pressure of cooperating disc springs 17 are movable.

The differential piston 2 moves evenly driven through the first pressure range 3 with a system pressure p1 on the end position damping too. The displaced hydraulic fluid in the second pressure range 4 . 5 can directly into the hydraulic line 7 drain, is therefore almost depressurized and does not contribute to the braking of the differential piston 2 at. Once the damping pin 10 in one below the damper pin 10 located damping chamber 11 , also referred to as a damping chamber or third pressure range, is sufficient, the third pressure range 11 from the hydraulic line 7 cut off.

The hydraulic fluid can now only by a residual gap 8th in the second pressure range 4 . 5 and then into the hydraulic line 7 flow back. This stagnation creates a damping pressure p3 in the third pressure range 11 that the differential piston 2 decelerating. As soon as the pressure p3 in the pressure range 3 a greater force on the, preferably three, locking pin 15 exerts, as the contact pressure of the provided disc springs 17 is, the locking pin 15 together with a guide 13 from the bottom of the damping bush 12 pushed away and there is an additional connection between the third pressure range 11 and the second pressure range 4 . 5 , Through this additionally released cross-section over the hydraulic fluid in the third pressure range 11 can flow off, a further increase in the pressure p3 is prevented. As soon as the pressure p3 in the third pressure range 11 decreases again and the contact pressure of the disc springs 17 the on the locking pin 15 If the applied pressure exceeds p3, the stoppers become 15 again against the bottom of the damping bush 12 pressed and the additionally released cross-section closes. Thereby, the height of the pressure p3 becomes the third pressure range 11 regulated and the braking effect on the differential piston 2 receive.

The opening pressure is determined by the ratio of the cup spring force to the effective area 16 the locking pin 15 certainly.

The damping chamber 11 and the damping pin 10 have cross-sections, the penetration of the damping pin 10 in the damping chamber 11 a residual gap 8th let through the hydraulic fluid from the damping chamber 11 in the second pressure range 4 . 5 can escape. This way, through the residual gap 8th realized a throttle effect, since in the damping chamber 11 enclosed hydraulic fluid only over the residual gap 8th in the second pressure range 4 and thus over the hydraulic line 7 can get into the hydraulic fluid tank.

The hydraulic line 7 for diverting the hydraulic fluid from the second pressure range 4 . 5 is thus up to the residual gap 8th no longer in direct fluid communication with that in the damping chamber 11 enclosed hydraulic fluid.

To ensure this is the cross section of the damper pin 10 smaller than the cross section of the damping chamber 11 trained to the residual gap 8th to ensure the passage of hydraulic fluid. The effective passage cross section of the residual gap may be chosen such that damping the movement of the piston 2 with a maximum adjustable damping is enabled. The maximum adjustable damping can be predetermined, for example, in the design of the hydraulic drive.

According to the invention, the closure element changes 15 during its movement through the provided disc springs 17 advantageously the cross section over the hydraulic fluid in the third pressure range 11 over the hydraulic line 7 can flow out, whereby a further increase in the pressure p3 is prevented.

The movable closure element 15 and released by this cross section act as a check valve with spring bias and cause a damping of the piston 2 automatically adjusts, so that the differential cylinder can be made application independent.

LIST OF REFERENCE NUMBERS

1

Differential cylinder arrangement, differential cylinder

2

piston

3

first pressure range, system pressure p1

4

second pressure range, alternating pressure p2

5

second pressure range, alternating pressure p2

6

piston rod

7

hydraulic line

8th

remaining gap

10

damping pin

11

Damping chamber, pressure range 3 , Damping pressure p3

12

damping bush

13

guide

15

Locking pin, movable closure element, axially movable part

16

Working surface, acted upon with damping pressure surface of the plug

17

Belleville spring

Claims (11)

Differential cylinder arrangement ( 1 ) for a hydromechanical drive for actuating an electrical switch, in particular a high-voltage switch, comprising: - a first pressure range ( 3 ) for pressurizing with a system pressure (p1); A second pressure range ( 4 . 5 ); A piston movable in a movement range ( 2 ), which depends on a pressure difference between the first and the second pressure range ( 3 . 4 . 5 ) is movable; A damping device which, during a movement of the piston ( 2 ) in the direction of the second pressure range ( 4 . 5 ) an attenuation against the movement of the piston ( 2 ), wherein the damping adjusts automatically, and - the damping device a damping chamber ( 11 ) on a piston ( 2 ) opposite end of the second pressure range ( 4 ) and one on the piston ( 2 ) in the direction of the second pressure region protruding damping pin ( 10 ) having the damping pin ( 10 ) and the damping chamber ( 11 ) are formed so that the damping pin ( 10 ) in a range of motion in the damping chamber ( 11 ) and thus the second pressure range ( 4 . 5 ) from the damping chamber ( 11 ), characterized in that the damping device comprises a damping bushing ( 12 ), in whose interior the damping chamber ( 11 ) forms a third pressure region which is connected to at least one movable closure element ( 15 ) is closable and the movable with the damping chamber ( 11 ) cooperating closure element ( 15 ) during a movement of the piston ( 2 ) by means of a contact pressure of at least one cooperating disc spring ( 17 ) is movable. Differential cylinder arrangement ( 1 ) according to claim 1, characterized in that the damping pin ( 10 ) and the damping chamber ( 11 ) are formed so that after the penetration of the damping pin ( 10 ) in the damping chamber ( 11 ) a residual gap ( 8th ) remains, which has a predetermined passage cross-section. Differential cylinder arrangement ( 1 ) according to claim 2, characterized in that the predetermined passage cross-section is chosen such that this predetermined maximum damping against the movement of the piston ( 2 ) causes. Differential cylinder arrangement ( 1 ) according to one of the preceding claims, characterized in that the damping chamber ( 11 ) and the second pressure range ( 4 . 5 ) via at least one hydraulic line ( 7 ) are directly or indirectly connectable to a hydraulic fluid reservoir. Differential cylinder arrangement ( 1 ) according to claim 4, characterized in that after reaching the below the damping pin ( 10 ) located third pressure range ( 11 ) of the damping pins ( 10 ) a separation of the third pressure range ( 11 ) from the tank connection ( 14 ), the hydraulic fluid initially only through the residual gap ( 8th ) in the second pressure range ( 4 . 5 ) and then flows back into the hydraulic fluid reservoir, wherein the damping pressure (p3) resulting from this congestion in the third pressure range ( 11 ) the differential piston ( 2 ) decelerates. Differential cylinder arrangement ( 1 ) according to claim 5, characterized in that the at least one closure element ( 15 ) from the bottom of the damping bushing ( 12 ) as soon as the damping pressure (p3) in the third pressure range ( 11 ) a greater force on the at least one closure element ( 15 ) exerts, as the contact pressure of the provided at least one plate spring ( 17 ) and an additional connection between the third pressure range ( 11 ) and the second pressure range ( 4 . 5 ) is formed, through which the hydraulic fluid in the third pressure range ( 11 ) flows out. Differential cylinder arrangement ( 1 ) according to claim 6, characterized in that the at least one closure element ( 15 ) against the bottom of the damping bushing ( 12 ) compresses as soon as the damping pressure (p3) in the third pressure range ( 11 ) decreases and the contact pressure of at least one plate spring ( 17 ), which on the at least one closure element ( 15 ) exceeds the applied pressure force (p3), the additional connection between the third pressure range (p3) 11 ) and the second pressure range ( 4 . 5 ) closes. Differential cylinder arrangement ( 1 ) according to one of the preceding claims, characterized in that the opening pressure by the ratio of the force of the plate spring ( 17 ) to the effective area ( 16 ) of the closure element ( 15 ) is determined. Differential cylinder arrangement ( 1 ) according to one of the preceding claims, characterized in that three movable closure elements ( 15 ) are provided. Differential cylinder arrangement ( 1 ) according to one of the preceding claims, characterized in that the movable closure element ( 15 ) is a movable part in the axial direction, in particular a closure pin. Hydromechanical drive for a high-voltage circuit breaker with a differential cylinder arrangement ( 1 ) according to one of the preceding claims.

Images