WO2006106070A1

WO2006106070A1 - Damping device for linear drives

Info

Publication number: WO2006106070A1
Application number: PCT/EP2006/061201
Authority: WO
Inventors: Frédéric Demetz
Original assignee: Bosch Rexroth Ag
Priority date: 2005-04-02
Filing date: 2006-03-30
Publication date: 2006-10-12
Also published as: DE102005015216B4; DE102005015216A1

Abstract

The invention relates to a damping device for linear drives, having pneumatic damping means which are operatively connected to at least one stroke stop of the linear drive, the damping function being designed such that it can be retrofitted and set independently of the drive system, by the pneumatic damping means being arranged replaceably in the region of the outer stops of the linear drive and the return stroke which follows the damping stroke being realized in various ways with simple technical means.

Description

BOSCH REXROTH AG

Robert-Bosch-Str.2 71701 Schwi eberding

Damping device for linear drives

The invention relates to a damping device for linear drives according to the respective identical preamble of the independent claims 1 to 5.

From EP 1 460 276 A2 a pneumatic cylinder is known, in which for damping the

Movement in the area of the end positions, suitable damping means integrated in the end covers LK: hv are. These consist of a throttle system, which delivers the exhaust air near the end positions reached by the piston only delayed to the atmosphere. Such Endlagendämpfungssystem is suitable in principle for pneumatic cylinders of any kind, as well as for the interest here linear drives.

In linear actuators, piston-cylinder units with and without piston rod can be used. The force generated by the driving pressure means on the piston is transmitted via the piston rod or a driver performing the same function on a carriage of the linear drive, which is movable along a stationary to the piston-cylinder unit arranged linear guide. As linear actuators of interest here, however, also linear drives come with other drive energy, such as in particular hydraulically or electromagnetically driven linear actuators in question.

However, the structural integration of a damping device of the type introduced in such a compact linear actuator is difficult. In particular, an integrated damping device allows an adjustment of the damping length and the degree of damping - if at all - only very expensive. Often a partial disassembly of the linear drive is required.

From the general state of the art are also externally attached to a linear drive, and therefore easier replaceable damping means out. However, these are usually formed only in the form of passively acting elastomeric elements, so that an adjustment of the damping length and the degree of damping is only very limited in the context of an exchange of the elastomer element is possible.

The invention is therefore based on the object to provide an externally attached to a linear drive easily accessible damping device whose damping function is easily adjustable. The stated object is achieved by a damping device of the genus in modern art by the characterizing features of the independent claims 1 to 5. Further advantageous embodiments are specified in the dependent claims.

The invention consists essentially in the fact that active pneumatic damping means are arranged so interchangeable in the region of the outer stops of a linear drive, and that both the damping as such and a restoring return stroke from each of the same damping stroke are effected.

According to a first embodiment of a device according to the invention damping device for linear drives, with axially adjustable outside the linear drive arranged damping means, which are in operative connection with at least one also external stroke stop of the linear drive, wherein the damping stroke via the damped retraction of a piston rod, the return stroke on realized in the piston rod frontally integrated magnet, which is magnetically frictionally held on the stop of the linear drive and taken away.

To accomplish the return stroke so here is a magnet arrangement is effective, which adheres to one of the end stops with magnetic holding force. If after completion of the end stop in the direction of damping of the piston-cylinder assembly, the damping device has moved together and a vent screw the pneumatic cushioning pad was vented, then the working stroke of the working cylinder of the drive which also consists of a piston-cylinder arrangement damping device is pulled apart again by the piston or the piston rod of the damping device is retracted by the magnetic holding force back to the original position. Alternatively, according to a second embodiment, the return stroke can also take place via a compression spring integrated in the interior space, which is compressed during the damping stroke and brings the piston rod back into the initial position by springback. Here, the damping is effected as usual pneumatically by the compression by the piston in the pressure medium chamber of the damping cylinder in the end position range. When reversing the motion of the linear actuator piston rod is returned to its original position by the previously also compressed compression spring moves back again.

Alternatively, according to a third embodiment of the return stroke of the piston rod is realized via a counter ventilation of the interior. Thus, the piston rod is moved back to the damping stroke back to the starting position before the damping engagement.

According to a fourth alternative embodiment, the return stroke of the piston rod is effected via an axially elastic element arranged on the stroke stop of the linear drive, which end face acts on the piston rod in the end stop position.

Finally, it is proposed according to a fifth embodiment that the stroke stop of the linear drive in the region of the end stop position comes into positive engagement with the front end of the piston rod, wherein the return stroke takes place by positive movement entrainment of the piston rod.

From these alternative embodiments of the invention damping means can be selected for a linear drive according to technical and dynamic requirements.

Important in all the illustrated embodiments is that in addition to the adjustable damping hereby also an adjustable return stroke can be done after damping to bring out the linear drive from its end positions again. This is done from each a working stroke of the linear drive out. Incidentally, the external Anbringbar speed of the damping means, the same also depending on the desired damping and restoring behavior interchangeable.

In the different embodiments, the damping function as such but basically always from a pneumatic cushioning. Preferably, the bleed screw of a cylinder bottom side exhaust throttle is adjustable and so the degree of damping can be adjusted from the outside. Alternatively, it is also possible that the degree of pneumatic damping via a fixed Abluftblende or a throttle bore in a cylinder bottom end portion of the damping device is predetermined, which establishes a connection between an interior and the atmosphere.

Further measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to FIGS. It shows:

1: a linear drive with a damping device,

FIG. 2: a magnetic return solution for the damping device,

FIG. 3: a return solution for the damping device by integrated spring,

FIG. 4 shows a return solution for the damping device through counter-ventilation,

Figure 5: a Rückhublösung for the damping device by elastic

Element, Figure 6: a Rückhublösung for the damping device by end stop with

Piston rod, and

Figures 6 and 8: each an embodiment of a non-adjustable damping.

Figure 1 shows the basic structure of said linear drive, in which the damping device according to the invention is used. The linear drive consists essentially of a lower fixed part as a sub-slide 20 and guided thereon movable part like a top slide 21. Within the sub-slide 20 are two - not recognizable in detail - working cylinder integrated pour the upper 21 on the lower slide 20 of Linear drive to move back and forth due to pressure medium.

Overlying, i. in direct engagement of the upper slide 21, there is a damping device 30a with a stroke stop 7 in an end position, which is formed by the lower slide 20 of the linear drive, which projects into the effective range of the upper slide 21. A further damping device 30b for the other end position is arranged stationary to the sub-carriage 20, whereas the corresponding - not further recognizable - stroke stop is formed by the upper slide 21.

The damping devices 30a and 30b are accessible from the outside, mounted on the front side of the linear drive, so that the desired damping function is easily adjustable from the outside.

FIG. 2 shows an embodiment of a damping device 30 used in this case. In this case, the damping device 30 consists of a cartridge-type cylinder housing 1 in which an adjustable venting screw 5 of an exhaust air throttle is placed at one end is. The piston rod 2 with a cylinder-side piston portion projects beyond a guide 3 in the region of the opening of the cylinder housing 1 to the outside. The sealing of this piston-cylinder arrangement via a piston seal 4 on the piston portion of the piston rod. 2

At the distal end of the piston rod 2, a magnet 6 is arranged frontally, this is designed as a permanent magnet. But it is also conceivable to form this as an electromagnet with switchable magnetic force.

If this damping device 30 is installed as shown in FIG. 1, the compression of the upper slide 21 of the linear drive takes place in the region near the end stop due to the penetration of the piston rod 2 into the housing 1 and the starting of this end position is correspondingly damped. The damping as such can be adjusted via the damping screw 5, via which the relief pressure in the final volume is adjustable.

In order to reset the piston rod 2 again from this end position into the starting position shown here, the piston rod 2 must be taken back by the slide or by a stroke stop 7 (according to FIG. 1) of the slide during the reversing movement.

This is done by the stop of the carriage, which rests against the piston rod 2, remain connected to each other in magnetic retention, so that the piston rod is taken in a reverse movement again with in the starting position. Of course, this assumes that the stroke stop 7 is iron-metallic.

Figure 3 shows an example in which within the piston-cylinder arrangement of a damping device 30 ', a compression spring 8 is integrated into the interior 9. Of the Interior 9 has for this reason on the damping side stop a cylindrical annular recess on the one hand and in the piston region of the piston rod 2 a cylindrical annular recess on the other. The compression spring 8 is guided in both rooms, so that they can not be compressed beyond the Hooke area in the maximum end stop in the interior 9.

Now, if the piston rod 2 driven by the action of a mitnehmenden stroke stop into the Endanschlagbereich, then there takes place as in the above examples, a pneumatic damping, which is adjustable via the bleed screw 5. The venting screw 5 releases more or less of the cross section of the venting channel.

If the end stop is reached and there is a reversal of motion of the linear drive, then the piston rod 2 is not taken from the carriage, but the integrated compression spring 8 causes a provision in the original position.

Figure 4 shows a damping device 30 ", in which in the damping, the piston rod 2 is pushed deep into the cylinder housing 1, so the interior 9, and the pressure increases within the same, so that here - as in all other examples - a pneumatic At the stop-side end of the inner space 9, a bleed screw 5 is again provided for the throttled venting, via which the relief pressure and thus the final damping effect can be set.

Also in this area, a check valve is arranged, which presses a ball 12 via a spring washer 1 1 on a valve seat 10 when the internal pressure increases in the damping direction, and prevents unwanted venting via this pressure medium connection. If the damping is carried out, the piston rod 2 is not taken away by the rear-moving carriage in this embodiment example, but via the check valve is a targeted controlled ventilation from the outside, so that the piston rod 2 is driven back over here to the starting position.

Figure 5 shows a damping device 30 '", in which the recovery after the above already described pneumatic damping by a coupling of the piston rod 2 with the entraining or returning stroke stop 7 takes place by this with the piston rod 2 via elastic elements 13, such as This elastic element 13 is expanded by the damping stroke and then recovers the piston rod 2 after damping has taken place, in which case the elastic element 13 consists of two parts, one of which is fixed to the stroke stop 7 of the The two, the elastic element 13 forming parts are then clamped together via conical complementary elements and thus together give the return spring elastic-like type.

FIG. 6 shows a design example of a damping device 30 "" in which a piston rod together with the piston region is part of the stroke stop 7 of the carriage. It could also be said that the stroke stop 7 contains a piston which dips into a cylinder housing 1 which is open on one side and connected to an opposite stroke stop 7. The damping is carried out pneumatically in the same manner as described above, but the return to the original position is carried out directly by the reversal movement of the carriage.

According to Figure 7, the degree of pneumatic damping via a replaceable exhaust vent 14 is fixed, which between a cylinder bottom side end piece 15 with Sealing ring 16 and the cylinder housing 1 is arranged to establish a connection between an interior 9 and the atmosphere.

According to Figure 8, the degree of pneumatic damping via a throttle bore 17 in the cylinder bottom end piece 15 is realized, which establishes a connection between an interior 9 and the atmosphere. The throttle bore 17 is at the same time also the seat of a check valve arrangement 18, so that overall the function of a throttle check valve results.

In all cases, the damping device 30 - 30 "" mounted on the outside of the linear drive and thus also accessible to select or adjust the damping easy.

LIST OF REFERENCE NUMBERS

cylinder housing

piston rod

guide bush

piston seal

adjustment

magnet

Stroke stop

compression spring

inner space

ball socket

spring washer

Ball elastic element

exhaust panel

tail

seal

throttle bore

Check valve assembly

Sub slide of the linear drive

Upper slide of the linear drive

attenuator

Claims

Patent claims

1. Damping device for linear drives, with axially adjustable outside the linear drive arranged damping means, which are in operative connection with at least one also outer stroke stop (7) of the linear drive, wherein the damping stroke via the damped retraction of a piston rod (2), characterized the damping stroke takes place on the basis of a pneumatic damping, and the return stroke takes place via a magnet (6) which is integrated in the piston rod (2) and which is magnetically frictionally held and taken along on the stop (7) of the linear drive (FIG. 2).

2. Damping device for linear drives, with axially adjustable outside the linear drive arranged damping means, which are in operative connection with at least one also external stroke stop (7) of the linear drive, wherein the damping stroke via the damped retraction of a piston rod (2), characterized in that the damping stroke takes place due to a pneumatic damping, and the return stroke takes place via a pressure spring (8) integrated in the interior space (9), which is compressed during the damping stroke and brings the piston rod (2) back into the starting position by springback (FIG. 3).

3. Damping device for linear drives, with axially adjustable outside of the linear drive arranged damping means, which are in operative connection with at least one also outer stroke stop (7) of the linear drive, wherein the damping stroke via the damped retraction of a piston rod (2), characterized in that the damping stroke is due to a pneumatic damping, and the return stroke of the piston rod (2) via a counter ventilation of the interior (9) takes place (Fig. 4).

4. Damping device for linear drives, with axially adjustable outside the linear drive arranged damping means, which are in operative connection with at least one also external stroke stop (7) of the linear drive, wherein the damping stroke via the damped retraction of a piston rod (2), characterized in that the damping stroke is due to a pneumatic damping, and the return stroke of the piston rod (2) via an on the stroke stop (7) of the linear drive arranged axially elastic element (13), which cooperates in the Endanschlagsposition frontally with the piston rod (2) (Fig 5).

5. Damping device for linear drives, with axially adjustable outside of the linear drive arranged damping means, which are in operative connection with at least one also external stroke stop (7) of the linear drive, wherein the damping stroke via the damped retraction of a piston rod (2), characterized in that the damping stroke takes place on the basis of pneumatic damping, and a piston rod is arranged on the stroke stop (7) of the linear drive in the region of the end stop position, the return stroke being determined by movement of the piston rod of the stroke stop (11) projecting into the interior of the cylinder housing (1). 7) takes place (Fig. 6).

6. Damping device according to one of the preceding claims, characterized in that the degree of pneumatic damping via an adjusting screw (5) of an exhaust throttle is adjustable, which establishes a connection between an interior (9) and the atmosphere.

7. Damping device according to one of the preceding claims 1 to 5, characterized in that the degree of pneumatic damping via an exhaust port (14) or a throttle bore (17) in or on a cylinder bottom end piece (15) is predetermined, which is a connection between a Interior (9) and the atmosphere manufactures.

8. Damping device according to one of the preceding claims, characterized in that the interior space (9) via a parallel-connected check valve (10, 11, 12) is closed by pressure medium (Fig. 4).

9. Damping device according to one of the preceding claims, characterized in that the type of return stroke of the piston rod (2) on the interchangeability of damping means is selectable.

10. Use of a damping device according to one of the preceding claims for cushioning in a pneumatic, hydraulic or electromagnetic linear drive,