EP3556478B1 - Vibration driving with a multi-surface cylinder - Google Patents

Description

On the one hand, the invention relates to the use of a cylinder for driving vibrations. On the other hand, the invention relates to a fluid circuit for driving vibrations, comprising a cylinder. Next, the invention relates to a driving method for a vibration-driven cylinder.

In track construction, track beds made of ballast or the like are used as a base for sleepers. For production and/or recycling, the ballast is pressed ("tamped") under the sleepers, and the tracks are thus lifted. Tamping units are used, which pierce the ballast with a tamping tool, such as a tamping pick, or a pair of tamping tools, and which then move the ballast under the respective slide threshold. A vibrating or swinging or oscillating tool is of dual benefit in order to facilitate penetration of the tool into the ballast on the one hand and to achieve a solidifying compaction of the ballast on the other hand. A vibration drive, such as a fluidic vibration drive, serves to drive at least one tamping tool.

the WO 2014 / 127393 A1 states as state of the art mechanically connecting a hydraulic cylinder for an infeed movement and a hydraulic cylinder for a vibration movement in series for tamping tools, with the disadvantage that, in addition to a high level of maintenance, is that an amplitude size cannot be freely adjusted.

the same WO 2014/127393 A1 discloses generically to provide a single hydraulic cylinder, such as a differential cylinder, with a displacement sensor for determining the position of the hydraulic cylinder, the hydraulic cylinder as an auxiliary drive depending on the displacement sensor signal and is controlled as a vibratory drive, with at least one servo or proportional valve preferably being provided for actuation.

This construction leads to high demands on the control valve: For example, if a differential cylinder vibrates, a larger amount of valve deflection is necessary to apply pressure to the piston rod side in order to achieve the same forces on both sides of the piston. For example, in the case of simultaneous vibration and superimposed piston extensions, a valve opening that is larger in terms of fluid quantity is necessary for supplying fluid to the piston side facing away from the rod. Consequently, the above construction disadvantageously results in a conflict of objectives or an inequality in terms of regulation.

The construction mentioned also leads to poor efficiency. Fluids are compressible. In addition to the gases regarded as "compressible fluids", the liquids designated as "incompressible fluids" also exhibit elasticity; for example, a compressibility factor of 0.7% to 0.8% per 100 bar can be assumed for mineral oils. From this it follows for the above construction with a single hydraulic cylinder in differential cylinder design that in order to generate the vibration, the entire fluid volume in the respective cylinder chamber, i.e. the volume for the piston extension movement in addition to the vibration volume, must be compressed (and relaxed) once per vibration cycle using energy.

the WO 2016 / 054667 A1 discloses a track tamping machine with two tamping units that can be displaced transversely independently of one another and that carry auxiliary cylinders for pivoting tamping arms for compacting ballast.

the EP 2 902 546 A1 discloses a ballast bed compaction device which provides a stabilization unit on a machine frame, which is equipped for gripping around a rail head. By oscillating the stabilization unit by means of a hydraulic cylinder vibrator, a horizontal oscillating of the track is achieved, which leads to a settlement of the track on the ballast bed.

DE 199 12 984 A1 discloses a double acting piston actuator having a floating piston assembly provided at one end of a piston rod. Z

Disclosure of Invention

In contrast, the invention is based on the object of creating a vibration drive with a high level of efficiency. Aspects of series production and/or aspects of productive use, such as producibility with little effort, maintainability with little effort and/or a small installation space requirement, can advantageously be taken into account.

With regard to the fluid circuit for driving vibration, the object is solved by the features of claim 1. Regarding the driving method for vibration driving, the object is achieved by the features of claim 4. It is understood that improvements and modifications can be made to the present invention described in detail below without departing from the scope of the invention disclosed in the appended claims . Z

A further advantage is that several functions can be integrated into a multi-surface cylinder as a single assembly, so that on the one hand assembly work during production and maintenance can be reduced and on the other hand space can be saved or for other functions, such as a larger piston surface and/or a longer piston extension stroke, can be used. If it is a piston-extending feed drive, a high extension force can be achieved.

A multi-surface cylinder can be understood to mean a fluid cylinder on whose piston there are at least three fluidically active piston surfaces. The piston surfaces can be pressurized, for example, via cylinder chambers or fluid chambers that do not fluidly communicate with one another.

As a further development, it is proposed to use a rapid traverse cylinder as a multi-surface cylinder. A rapid travel cylinder can be described as having at least one annular piston surface on the piston rod side, an oppositely directed annular piston surface or one facing away from the piston rod and a rotary piston surface facing away from the piston rod, with the piston surfaces facing away from the rod being structurally separate and not communicating fluidically.

It is also proposed as a development to use a tandem cylinder as a multi-surface cylinder. A tandem cylinder can be described as a fluid cylinder on the piston rod of which at least two piston heads are arranged offset in the longitudinal direction, with two piston surfaces facing one another and arranged one behind the other not communicating fluidly in a structurally separate manner.

A preferred fluid is a hydraulic fluid because of the higher pressures that can be achieved, in particular a hydraulic fluid for mobile applications because of the biodegradability.

The fluid circuit Z according to the invention has the advantage that the piston surfaces of the multi-surface cylinder and/or the valves can be optimized, such as optimized in terms of efficiency.

By applying pressure to the third piston surface and the piston surface of the first two piston surfaces arranged in the same way, Z has a high overall force available, for example for a penetration movement of the tamping tine to be driven into a ballast bed.

Preferably, in a construction that is particularly easy to control, the first two piston surfaces each have an effective piston surface that is at least approximately the same size. That's how it's done the areas of the same amount in terms of amount when the piston is displaced achieves an approximately equally large volume flow in/out of the respective cylinder chamber.

Having an accumulator in communication with the third piston surface has several advantages. On the one hand, to increase efficiency, compression of the fluid in the cylinder chamber belonging to the third piston surface can be replaced by compression (e.g. a gas bubble) and/or compensatory movement (e.g. a spring-loaded pressure accumulator base) and/or the like in/on the pressure accumulator. On the other hand, a minimum amplitude and/or a maximum amplitude of the vibration movement can be ensured and/or optimized, such as efficiency-optimized and/or function-optimized, by appropriate dimensioning of the pressure accumulator (e.g. a gas bladder volume and/or a pressure accumulator bottom travel path).

Since the first valve is a vibratable rain valve, this facilitates a vibratory movement of the piston and thus of the tamping tine to be driven. Preferred control valve designs include a proportional valve and/or a servo valve. Z The control valve is connected Z to a control device for specifying vibration, in order to bring about a vibration that can be specified according to amplitude and/or frequency and/or energy. The control valve is therefore acted upon in an oscillating manner. For example, the control valve is an electrically and/or hydraulically and/or pneumatically pilot-controlled valve with one and/or two stages. According to a preferred development, the fluid circuit and in particular the multi-surface cylinder and the first valve are suitable for a frequency of up to approximately 50 Hz, more preferably with a frequency of up to approximately 40 Hz, even more preferably with a frequency of up to approximately 35 Hz , and/or to vibrate at a frequency of about 25 to about 40 Hz. Experience has shown that these frequency ranges are particularly advantageous for compacting a ballast bed.

According to a further preferred development, the hydraulic circuit and in particular the multi-surface cylinder and the first valve are suitable for the piston relative to the cylinder housing with an amplitude of up to approximately 6 mm, more preferably up to approximately 3 mm, even more preferably of at least approximately 3 mm, and/or most preferably oscillates to about 2mm. Experience has shown that this vibration promotes rapid and efficient compaction of a ballast bed.

In a further development, the fluid circuit has a measuring device for measuring the fluid pressure in/on the cylinder and/or in/on the first valve. By measuring the (vibrating) fluid pressure profile, a ballast bed compaction can be checked, for example.

Driving method Z includes Z both pressurizing the third piston face and vibrating the first valve about a shifted zero point to simultaneously vibrate drive and piston extend. The method step thus contains two parallel steps which can preferably be carried out independently of one another, can be carried out independently of one another in terms of amount and/or can be started and ended independently of one another. In contrast to the prior art, where a single cylinder chamber is simultaneously pressurized for piston displacement and vibration driving, the two parallel steps allow, for example, a constantly progressive compaction of a ballast bed by taking two relatively simple control actions.

The control method for the multi-surface cylinder is preferably particularly simple and reliable in terms of control technology, the first piston surface and the second piston surface each having an effective piston surface of the same size, and the vibration according to a zero-point symmetrical function, such as such a sine function.

Driving with a zero-point symmetrical function, in particular a sine function, is particularly uniform and scalable.

Brief description of the drawings

• Figur 1 einen Teil eines Schaltplans einer erfindungsgemäßen Fluidschaltung zum Vibrationsantreiben beispielsweise eines Stopfpickels gemäß einer ersten Ausführungsform,
• Figur 2 einen Teil eines Schaltplans einer erfindungsgemäßen Fluidschaltung zum Vibrationsantreiben beispielsweise eines Stopfpickels gemäß einer zweiten Ausführungsform, und
• Figur 3 einen Teil eines Schaltplans einer erfindungsgemäßen Fluidschaltung zum Vibrationsantreiben beispielsweise eines Stopfpickels gemäß einer Variante der zweiten Ausführungsform.

Preferred exemplary embodiments of the invention are explained in more detail below using schematic drawings. Show it:

• figure 1 part of a circuit diagram of a fluid circuit according to the invention for vibrating, for example, a tamping tool according to a first embodiment,
• figure 2 a part of a circuit diagram of a fluid circuit according to the invention for vibrating, for example, a tamping tine according to a second embodiment, and
• figure 3 a part of a circuit diagram of a fluid circuit according to the invention for vibrating, for example, a tamping tine according to a variant of the second embodiment.

the 1 shows a first embodiment of the invention. In the present case, a fluid circuit 1 for driving vibrations comprises a multi-surface cylinder or multi-surface fluid cylinder designated as a whole with 2, a vibration valve 4 as the first valve, an extension valve 6 as the second valve and a pressure accumulator 8.

In the first embodiment, the multi-surface cylinder 2 is a rapid travel cylinder 10. It has a cylinder housing 12 with a cylinder wall 18 closed at each end with a cylinder base 14 and a cylinder cover 16 and with a stamp 20 concentric thereto and fixed to the cylinder base. A piston 24 with an annular piston head 26 , an adjoining hollow-cylindrical piston rod 28 and a piston rod head 30 at the axial end is accommodated therein so as to be displaceable along a longitudinal axis 22 defined by the cylinder wall 18 .

The rapid travel cylinder 10 has three piston surfaces which are operatively arranged for the axial displacement of the piston and which are collectively designated as 32 . A first piston surface 34 is located on the side of the piston rod 28 on the piston head 26. A second piston surface 36 is located on the inside of the piston rod head 30, facing the punch 20.

A third piston surface 38 is located on the side facing away from the piston rod 28 on the piston head 26.

The piston surfaces 32 each axially delimit a chamber 40 . In the present case, a first chamber 42 is defined by the first piston surface 34 , the cylinder wall 18 , the cylinder cover 16 and the piston rod 28 . An overpressure in the first chamber 42 acts on the first piston surface 34 to retract the piston rod 28 . A second chamber 44 is presently defined by the second piston surface 36 , the piston rod 28 and the plunger 20 . An overpressure in the second chamber 44 acts on the second piston surface 36 to extend the piston rod 28. A third chamber 46 is presently defined by the piston 24, the cylinder wall 18, the cylinder base 14 and the plunger 20. An overpressure in the third chamber 46 acts on the third piston surface 38 to extend the piston rod 28.

The vibration valve 4 is a valve that can be vibrated in a predetermined manner. It is provided as a 4/3-way valve with two working connections 48 and supply connections 50. For example, it is a proportional spool valve and has an electrically controllable pilot device that can deflect the spool (not shown), such as stimulating preferably symmetrical oscillations about an adjustable operating point/zero point. One working connection 48 of the vibration valve 4 communicates fluidly with the first chamber 42. The other working connection 48 of the vibration valve 4 communicates fluidly through the plunger 20 with the second chamber 44.

The extension valve 6 is a switchable valve, for example a pilot-operated pressure-limiting valve with two supply connections 50 and a working connection 48 which communicates fluidly with the third chamber 46 .

The pressure accumulator 8 communicates fluidly with the third chamber 46. For example, the pressure accumulator 8 branches off the line between the extension valve 6 and the third chamber 46.

To vibrate the piston 24, the vibration valve 4 is vibrated so that the chambers 42 and 44 are alternately pressurized with fluid at a frequency of up to 35 Hz. For example, fluid pressure is built up and released once in each period in each of the chambers 42,44. In this case, the piston 24 is, for example, by one Amplitude of up to 2mm shifted relative to the cylinder body. The piston movement pumps the fluid back and forth between the third chamber 46 and the pressure accumulator 8 . Since the piston areas 34 and 36 are of the same size, a symmetrical oscillation of the disc of the vibration valve about a zero point for pressurizing the chambers 42, 44 is made possible.

To extend the piston 24 , fluid is fed under pressure to the third chamber 46 via the extension valve 6 , fluid is fed under pressure to the second chamber 44 via the vibration valve 4 , and fluid is discharged from the first chamber 42 via the vibration valve 4 .

Fluid is supplied under pressure through the extension valve 6 to the third chamber 46 to simultaneously extend and vibrate the piston 24 . The zero point of the vibration valve and the amplitude of the oscillation of the slide of the vibration valve 4 are shifted in such a way that on the one hand fluid pressure is built up and released once in each period in each of the chambers 42, 44, and on the other hand compared with the volume flow in the first chamber 42 the volume flow in the third chamber 46 piston path corresponding volume flow excess flows into the second chamber 44.

For example, the cylinder housing is coupled to a (not shown) machine frame or the like, such as fixed, articulated and/or pivoted, and the piston is coupled to a tamping tine (not shown) to be driven, such as fixed, articulated and/or pivoted . Since the mass of the cylinder piston is usually smaller than the mass of the cylinder housing, this construction is energetically favorable and therefore has a high level of efficiency.

According to a variant (not shown), the multi-surface cylinder 2, the valves 4 and 6 and the pressure accumulator 8 form a compact assembly, so that space can be saved and the entire assembly can be exchanged for a replacement assembly to increase the productive time.

According to a variant (not shown) of the first embodiment, a cylinder housing-side coupling to the tamping tine and a piston rod-side coupling to the machine frame are provided, for example due to space considerations and/or in the case of different mass ratios.

the 2 shows a second embodiment of the invention. This differs from the first embodiment at least in that the multi-surface cylinder 2 is a tandem cylinder 52 . This has in the cylinder housing 12 axially approximately centrally between the cylinder base 14 and the piston rod-side axial end of the cylinder housing 12 an annular intermediate cylinder base 54 fixed to the cylinder wall 18, which divides the cylinder 2 into two cylinder working chambers 56 arranged axially one behind the other. In addition to the disk-shaped piston head 26, which is fixed to one another in the cylinder working chamber 56 near the cylinder base and is axially displaceable in a fluid-tight manner, and the piston rod 28, which is mounted in a fluid-tight manner in the intermediate cylinder base 54, an intermediate piston base 58 that is axially displaceable in a fluid-tight manner in the working chamber 56 remote from the cylinder base.

The piston surfaces 32 each axially delimit a chamber 40 . The first chamber 42 is defined by the first piston surface 34 , the cylinder wall 18 , the intermediate cylinder floor 54 and the piston rod 28 . An overpressure in a first chamber 42 acts on the first piston surface 34 to retract the piston rod 28. The second piston surface 36 is located on the cylinder (intermediate) base side on the intermediate piston base 58. The second chamber 44 is defined by the second piston surface 36, the cylinder wall 18, the piston rod 28 and the cylinder intermediate base 54 are defined. An overpressure in the second chamber 44 acts on the second piston surface 36 to extend the piston rod 28. The third chamber 46 is defined by the piston 24, the cylinder wall 18 and the cylinder base 14. An overpressure in the third chamber 46 acts on the third piston surface 38 to extend the piston rod 28. The piston surfaces 34 and 36 are of equal size. A space between the intermediate piston base 58 and the axial end of the cylinder housing 12 on the piston rod side is preferably vented.

the 3 shows a variant of the second embodiment. A fourth piston surface 62 is located on the cylinder cover side on the intermediate piston floor 58. A fourth chamber 60 is defined by the fourth piston surface 62, the cylinder wall 18, the cylinder cover 16 and the piston rod. An overpressure in the fourth chamber 60 acts on the fourth piston surface 62 to retract the piston rod 28. The extension valve 6 is an on/off valve, like a controlled 4/3-way valve. Compared to the basic variant of the second embodiment, more fluid pressure can be applied to the piston rod for retracting, for example in order to retract a heavier attachment or to raise a rail.

The fourth chamber 60 communicates with a pressure accumulator 8 in order to enable the piston 24 to vibrate with improved efficiency.

A sub-variant not shown includes, instead of or in addition to the pressure accumulator 8, a compensating piston (compensating element as well as compensating membrane) that can be displaced between two compensating chambers of approximately the same size, of which one compensating chamber communicates fluidly with the third chamber 46, and the other compensating chamber communicates with the fourth Chamber 60 communicates fluidly. Compared to the above solution with two pressure accumulators 8, this again improves the efficiency.

Claims (5)

1. Fluid circuit for vibration driving, the circuit comprising a multiple-surface cylinder (2, 10, 52), a first valve (4) which is connected to the first two counteracting piston surfaces (34, 36) of a piston (24) of the multiple-surface cylinder (2, 10, 52), and a second valve (6) which is connected to a third piston surface (38), the multiple-surface cylinder (2, 10, 52) having a first piston surface (34), a second piston surface (36) which is arranged so as to counteract the first piston surface (34), and a third piston surface (38) which is arranged so as to act identically to the second piston surface (36),
   the first valve (4) being a control valve which can be vibrated and is connected to an actuating device for vibration specification; characterized in that the third piston surface (38) is a piston surface which acts so as to extend the piston when pressurized, and in that the second valve (6) is configured to make an extension of the piston (24) possible while the piston (24) is vibrating.
2. Fluid circuit according to Claim 1, the first two piston surfaces (34, 36) in each case having an active piston area of identical size.
3. Fluid circuit according to either of Claims 1 and 2, a pressure accumulator (8) being connected in a communicating manner to the third piston surface (38).
4. Actuating method for vibration driving for a multiple-surface cylinder (2, 10, 52) which has a first piston surface (34), a second piston surface (36) which is arranged so as to counteract the first piston surface (34), and a third piston surface (38) which is arranged so as to act identically to the second piston surface (36),

   the first piston surface (34) and the second piston surface (36) being loaded with pressure in an alternating manner for vibration driving;

   the first piston surface (34) and the second piston surface (36) being connected to a first valve (4), a slide of the valve (4) being vibrated for vibration driving; characterized in that,

   for simultaneous vibration driving and piston extension, the third piston surface (38) is loaded with pressure, and the first valve (4) is vibrated about a shifted zero point.
5. Actuating method according to Claim 4 for the multiple-surface cylinder (2, 10, 52), the first piston surface (34) and the second piston surface (36) in each case having an active piston area of identical size, and the vibration being specified in accordance with a zero point-symmetrical sine function.

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