JPH0343488B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a cylinder whose both axial ends are closed by a cylinder cover, and a cylinder which is guided in the cylinder so as to be movable in the axial direction and in a sealed state. a piston rod connected to the piston and passing through one cylinder cover; a magnet device comprising a permanent magnet supported by the piston; and at least one magnet device disposed on the outer peripheral surface of the cylinder and operable by the magnet device. The present invention relates to a piston cylinder unit, in particular a short stroke cylinder, comprising a signal generator.

(Prior Art) The piston cylinder unit of the above type generally has a cylinder manufactured by a casting method, and this cylinder is later subjected to secondary processing in a desired manner, and a signal generator is installed on the cylinder. is fixed with screws.

Piston-cylinder units of this type are extremely expensive due to their relatively large number of parts.
This is because a suitable casting mold must be prepared for each cylinder, and these molds are no longer needed after the casting process.

Another disadvantage of piston-cylinder units of this type is that the signal generator can only be adjusted within a limited range. usually,
This signal generator is fixed to the outer surface of the cylinder so as to be actuated depending on the end position of the piston.

(Problems to be Solved by the Invention) An object of the present invention is to improve the piston cylinder unit of the type described above so that it can be manufactured easily at low cost.
The object of the present invention is to provide a flexible piston adjustment display device which is compact and simple in structure, can function reliably, and can be precisely adjusted over the entire length of the cylinder.

(Means for Solving the Problems) In order to solve the above problems, according to the present invention,
A cylinder is constructed from a drawn profiled material, and on its outer circumferential surface at least one signal generator, configured for example as a so-called reed switch, is axially slidably held. extending in the axial direction of the cylinder, for
and at least one integrally molded axial guide over its entire length.

(Operations and Effects of the Invention) According to the present invention, at least one signal generator can be adjusted steplessly in the longitudinal direction of the cylinder and fixed at an arbitrary position.

Thus, not only is it possible to adjust the end position of the piston, but at a predetermined position of the piston, the signal generator can continue to generate a signal to provide an indication of the piston position.

Since the axial guide for the signal generator or signal generators is mounted on or in the outer circumferential surface of the cylinder during manufacture of the cylinder, the manufacturing costs of this cylinder are significantly reduced. for example,
By cutting the cylinder molding material, which is sold by the meter, into desired dimensions, cylinders of different lengths can be easily produced without much effort and expense.

The axial guide for the signal generator or generators requires very little subsequent fabrication and also allows for simple mounting and adjustment of the signal generator or generators. This is because the axial guide extends over the entire length of the cylinder and opens at the end face of the cylinder.

Depending on the selection of the cylinder molding material used,
One or more axial guides can be provided along the circumference of the cylinder without significantly increasing production costs.

The provision of several axial guides makes it possible to make the distance between two signal generators located one after the other in the axial direction particularly short. Moreover, in that case, the signal generators do not interfere with each other.

All of the above advantages are achieved with a compact piston-cylinder unit structure. It should be noted that such a compact unit construction is particularly advantageous when cylinders of this type are used as short-stroke cylinders, since the cylinders often have to be accommodated in limited and narrow spaces.

Further advantageous embodiments of the piston-cylinder unit according to the invention are described in the claims 2 to 20.

The cylinder described in claim 2 is:
It has a configuration particularly suitable for practical use, and can effectively fix multiple signal generators with a compact and simple configuration.

According to the embodiments described in claims 3 and 4, it is possible to easily mount the signal generator and to guide it accurately. Particularly in the embodiment according to claim 3, a particularly good compactness is achieved, since the axial guide does not increase the lateral dimensions of the cylinder.

According to the embodiment shown in claim 5, the cost and effort required for machining the cylinder to form the axial guide can be minimized.

The cylinder cover in the embodiment described in claim 6 is easy to manufacture and easy to install. The width of this cylinder cover, measured in the axial direction, can be very small, so that the possible stroke lengths of the piston are hardly restricted.

The cylinder of the extremely compact piston-cylinder unit obtained in this way does not have its length extended by the installation of a cylinder cover. Moreover, in that case, the maximum stroke length of the piston is approximately equal to the length of the cylinder itself.

In the embodiment according to claim 7, fixing elements, such as screws, which increase the size of the overall structure, can be omitted. Therefore, the compactness of the piston cylinder unit is further emphasized. Furthermore, this embodiment also eliminates the need for a separate sealing element in the cylinder cover.

In the embodiment according to claim 8, the magnetic device is located opposite the signal generator in any angular position of the piston or piston rod, so that the piston or piston rod is It is possible to maintain the relative rotational impediment and eliminate the need for this.

A particular advantage of the embodiment according to claim 9 lies in the quick and simple mounting of the ring magnet. This embodiment also ensures a reliable holding function.

According to the embodiment defined in claim 10, the surface of the ring magnet facing the signal generator is very small, so that precise switching between the ring magnet and the signal generator is possible. This results in the advantage that the switching hysteresis between the two switching processes in the signal generator can be minimized.

The embodiments according to claims 11 and 12 relate to making it possible to fix the ring magnet in an advantageous manner.

In the embodiments set forth in claims 13 and 14, the piston is optimally sealed to the cylinder.

In this case, if the magnetic field of the ring magnet is further implemented as described in claim 15, it is avoided that the magnetic field of the ring magnet exerts an undesirable effect.

According to the embodiments described in claims 18 and 19, the pressure medium conduit can be securely fixed, and the weight of the piston cylinder unit can be significantly reduced. in this case,
The thickness of the cylinder wall is reduced to a minimum value that does not cause any disadvantages in terms of strength, and only in the area of the connection for the pressure medium conduit is the connection strip such that a sufficient threading depth of the connection thread is obtained. It can be installed and reinforced. By suitably configuring the extraction tool, this connecting strip can be used during the production of the cylinder profile.
Since it can be molded directly onto the cylinder, a weight and cost reduction is achieved in the production of this connecting strip.

The embodiment defined in claim 20 not only simplifies the manufacture of pistons and piston rods, but also allows for example longer or shorter piston rods to be required at different points of use. In this case, the piston rod can be replaced later.

(Embodiments) Next, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

The embodiment of the piston-cylinder unit according to the invention shown in FIG. 1 represents a so-called short-stroke cylinder with extremely compact external dimensions. This type of short-stroke cylinder is especially used when the accommodation space is too small to accommodate a large working cylinder, or when the stroke of the piston or piston rod required to operate the valve is small. This is the case when

As is clear from FIGS. 1 and 2, the cylinder 1 has a cylinder bore 2 therein, and the piston 3 divides the cylinder bore 2 into two cylinder chambers 4 and 5. In this state, the cylinder is movably guided in the axial direction of the cylinder within the perforated portion.

The cylinder perforation 2 is closed on the end surface side of the cylinder 1 by cylinder covers 6 and 7. In this case, one cylinder cover 6 is attached to the piston 3
It is penetrated by a piston rod 8 connected to the piston rod 8.

Since the cylinder 1 according to the invention is constructed from a drawn material, high cylinder strength and low manufacturing costs are guaranteed. Also,
The final external contour of this cylinder 1 is already defined during its manufacture, and this is simply carried out by configuring the extraction tool accordingly. This situation is especially advantageous because the signal generator 10, which is slidable in the axial direction of the cylinder 1 and responds at a predetermined piston position, as shown for example in FIG. This is a case where it is attached to the outer circumferential surface 9 of 1.

When manufacturing cylinder 1 using the drawing method,
Axial guides 11 for the signal generator 10 are already drilled or integrally formed in or on the outer circumferential surface 9, and there is almost no need for subsequent secondary processing of these axial guides 11. do not have.

The cylinder 1 in the illustrated embodiment of the piston-cylinder unit has an approximately square or rectangular outer contour when viewed in cross-section and, when viewed as a whole, has an approximately rectangular parallelepiped shape.

The three outer walls or peripheral surfaces 12 of this cylinder 1 are each provided with an axial guide 11 consisting of a guide groove 13, preferably with a dovetail-shaped cross section.

The signal generators 10, only one of which is shown in FIG. It is guided by the bearing leg 14 in the guide groove 13 with a sliding clearance.

In this case, the axial guide 11 or its guide groove 1
3 is advantageously arranged in the longitudinal center of each cylinder outer circumferential surface 12. This is because at that point the thickness of the cylinder wall is at a minimum and thus the distance to the piston 3 guided in the cylinder is also at a minimum.

The reason why this short distance is advantageous is that the signal generator 10 is actuated via a magnetic device fixed to the piston 3, which will be described later, and the switching force, i.e. the magnetic field strength in the magnetic device, is
It is at the point where it decreases with increasing cylinder wall thickness.

It should be added here that the shape of the guide grooves 13 is not important, but the possibility of slidably supporting at least one signal generator 10 in each guide groove 13 is essential. That's what it means.

Further, the shape of these axial guides 11 is not limited to the shape of a recessed groove, but, for example,
Axial guidance can also be achieved by integrally molding a guide rail on the cylinder outer circumferential surface 12 and slidably mounting the signal generator 10 on this rail (not shown).

Next, with particular reference to FIG. 2, the structure of the piston-cylinder unit according to the invention will be described in detail.

The cylinder cover 7 facing the piston 3 on the side of the piston end face 15 without a piston rod (hereinafter referred to as the cylinder cover without a piston rod) is formed as a stamped part, and the end face side is inserted into the cylinder bore 2. It has been inserted.

Therefore, the cylinder perforation 2 is widened from the corresponding end surface 16 side to a depth approximately corresponding to the thickness of the cylinder cover 7. In the transition region of the cylinder bore 2 from this widened range to its nominal diameter range, a ring-shaped addition 17 is formed, which serves as a stop and a bearing surface for the cylinder cover 7.

The axially outward facing surface 18 of the cylinder cover 7 is aligned substantially co-aligned with the end surface 16 when inserted into the widening of the cylinder bore.

The fixing of this cylinder cover 7 without piston rod, which is constructed as a stamped part, in the cylinder bore 2 is carried out by welding, especially ultrasonic welding or laser welding. The resulting ring-shaped weld seam 22 serves, on the one hand, to hold the cylinder cover 7 and, on the other hand, to seal it against the cylinder bore 2.

Cylinder cover 7 without piston rod
is preferably disc-shaped. In that case, neither inward nor outward of the cylinder bore 2 are there any interfering protrusions or the like.

The second cylinder cover 6, which is penetrated by the piston rod 8, is inserted into the enlarged section 24 of the cylinder bore 2 from the side of the cylinder end face 23 opposite the end face 16. In this case, since the outer diameter of the cylinder cover 6 is equal to the diameter of the expanded section 24, a ring-shaped holding protrusion 25 is provided at the transition section from the expanded section 24 to the original cylinder bore 2. The cylinder cover 6 abuts on this holding protrusion 25 .

The depth of this widening section 24, measured in the axial direction of the cylinder 1, is greater than the thickness of the cylinder cover 6 in this region, so that the cylinder cover 6 is
It is buried within the cylinder bore 2 to some extent.

Safety ring 2 that holds the cylinder cover 6
6 is fixed in the circumferential groove 27 in the expansion section 24 and presses the cylinder cover 6 onto the holding projection 25. A ring seal 28 is housed between the cylinder cover 6 and the holding projection 25 to seal the cylinder chamber 4 from the outside.

This cylinder cover 6, which is penetrated by the piston rod 8, has a cap-like shape and has an axial end 31 in its hollow cylindrical central part 30.
A disc-shaped ring-shaped protrusion 32 is integrally formed. The radial edge 29 of the ring-shaped protrusion 32 is
It is received in the enlarged section 24 of the cylinder bore 2.

The hollow cylindrical central portion 30 is connected to the cylinder end surface 2
3 and has a central perforated portion 33 that protrudes outside. A guide bush 34 for guiding the piston rod 8 is provided in the central bored portion 33;
A corrugated sealing ring 35 for sealing the bore 33 with respect to the piston rod 8 is accommodated. In this case, the corrugated seal ring 35 is adapted to abut within the widened portion formed in the central perforation 33 from the side of the axial end 36 of the central portion 30 that is located opposite to the axial end 31 . It's getting old. Further, the position of the wave seal ring 35 is secured via a snap ring 39.

In order to define the positions of the two pistons, stop surfaces 37, 37', on which the piston 3 abuts at a predetermined end position, are integrally molded on the end faces of the cylinder covers 6, 7 facing inside the cylinder 1.

The piston 3 itself is preferably a piston rod 8.
Since it is constructed separately from the piston rod 8 and is connected to the piston rod 8 by screwing, the piston rod 8 can be easily replaced if necessary.

A magnetic device 38 consisting of a permanent magnet carried by the piston 3 itself can be actuated by acting on one or more signal generators 10 mounted around the periphery of the cylinder 1. It is therefore advantageous to design the signal generator 10 as a reed switch or inductive switch, as shown in FIG.

When the magnet device 38 passes by the signal generator 10 during the stroke movement of the piston 3, the magnetic force of the magnet device 38 causes the signal generator 1 to
0, the signal generator 10 generates electrical signals that are thereby used to control other functions.

The magnetic device 38 is fixedly connected to the piston 3 and the switching point of the signal generator or generators 10 can be determined by adjusting the signal generator 10 in the longitudinal guide 11 described above in the axial direction of the cylinder. Since it is controlled, it is possible not only to display the piston position but also to adjust the piston end position.

In order to effectively seal the piston 3 to the cylinder bore 2 and make it compact, the outer diameter of the piston 3 is smaller than the inner diameter of the cylinder bore 2, and the outer circumferential surface 4 of the piston 3 is made smaller than the inner diameter of the cylinder bore 2.
2 is integrally molded with a ring-shaped holding protuberance 43 that coaxially surrounds the piston 3 and projects from the piston 3 in the radial direction, and a ring seal 44 that slidably abuts on the cylinder bore 2. It is fitted onto this holding protrusion 43.

This ring seal 44, which is integrally formed with two lip seals, is configured such that in each direction of movement of the piston 3,
This ensures reliable mutual sealing of both cylinder chambers 4, 5, respectively.

The magnetic device 38 has as its main component a ring magnet 45 which is coaxially mounted on the piston end face 46 facing the piston rod 8. Therefore, the end surface 46 of the piston 3
is provided with a short sleeve-shaped centering extension 47 coaxially molded in one piece.

A ring magnet 45 which is advantageously disk-shaped.
is coaxially fitted over this centering addition 47, and its axial end is flanged radially outward. This results in
The ring magnet 45 can be tightened and held. Therefore, the ring magnet 45 is prevented from being accidentally separated from the piston 3.

This ring magnet 45 protrudes in the radial direction beyond the outer circumferential surface 42 of the piston 3 and reaches just before the inner surface of the cylinder bore 2, so that the magnet device 38 and the signal generator 10 are connected to each other. The radial distance between them is minimized.

The thus obtained piston-cylinder unit with high switching accuracy produces only an extremely small switching hysteresis due to the above-mentioned disk-shaped configuration of the ring magnet 45, which means that:
This is a very important point, especially for short stroke cylinders.

The ring magnet 45 protrudes radially from the outer circumferential surface 42 of the piston 3 and is subjected to a high load in the axial direction.
This is advantageous because it is fixed relative to 6.

In order to increase the switching ability of the magnet and to ensure that the axial dimensions of the magnet do not undesirably increase the switching hysteresis, a ring magnet 48 is provided which is inserted into the end face 46 of the piston and is connected to the end face 46 of the piston. Advantageously, it is aligned in line with 46.

In this way, the second ring magnet 4
8 comes into contact with a disc-shaped ring magnet 45 attached to the end surface 46 of the piston, and these two ring magnets form one common magnet device 38, The high magnetic force of the inserted ring magnet 48 is
It is transferred via a disc-shaped ring magnet 45. Therefore, this magnet device 38 has both a slight switching hysteresis due to the small axial dimension of the disc-shaped ring magnet 45 and high switching accuracy due to the strong magnetic field.

Note that instead of using the disc-shaped ring magnet 45, a magnetizable metal disc is simply provided,
It is of course also possible to deflect the magnetic field of the inserted ring magnet 48 in the direction towards the signal generator 10. In this case, it has proven particularly advantageous to construct the ring magnet as an oxide magnet.

In order to operate a piston-cylinder unit of double-acting construction, one connection hole 49, 49' is guided in each cylinder chamber 4, 5, and these connections supply and discharge pressure medium. The holes 49, 49' are threaded to make it possible to connect conduits or tubes for pressure medium.

A certain thread height is essential for reliable fixing of this type of pressure medium conduit or the like. Since the wall thickness of the cylinder 1 is the minimum dimension depending on the required strength, especially the first
As shown in the figure, the fourth cylinder outer wall or circumferential surface 50, which does not have an axial guide, is provided with a connecting strip 51 which is formed in one piece with the cylinder 1. This connecting strip 51 extends in the axial direction of the cylinder 1 over its entire length.

In the area where this connecting strip 51 is provided, the wall thickness of the cylinder 1 is significantly increased so that the connecting holes 49, 49' open through the connecting strip 51 into the interior of the cylinder 1. It becomes possible to leave it there.

The material thickness obtained in this way is sufficient to ensure a reliable fixing of the pressure medium conduit and, moreover, to ensure compactness in construction of the piston-cylinder unit according to the invention. It will not be damaged.

This connecting strip 51 is advantageously molded directly onto the cylinder 1 during production, preferably by drawing. Therefore, the manufacturing cost in that case can be kept low. It is only necessary to drill a threaded connection hole 49 in the connecting strip 51. It should also be noted in this case regarding the axial guide 11 that the longitudinal guide 11 extends over the entire length of the cylinder 1 and therefore
Similar to the connection strip 51, it is open at both end faces of the cylinder 1.

As is clear from the piston-cylinder unit in FIG. 3, which is a front view of the cylinder 1 shown in FIG. Each axial guide 11 is provided with a connecting strip 51 which projects from the outer circumferential surface 50 which is free of axial guides.

To attach the signal generator 10, attach the support leg 14 to the
This can be easily achieved by inserting the cylinder 1 into the axial guide 11 from the end surface side.

As is clear from FIGS. 1 and 3, the corner area 52 of the cylinder 1 is provided with a mounting bore 53 with a thread.
is fixed to an appropriate machine part or the like via this mounting hole 53.

The reason for configuring the cylinder 1 in a square or rectangular shape is clear from this. If the cylinder 1 is cylindrical, it will be difficult to provide a mounting hole in the cylinder, and in some cases ,
Other means of retention will have to be taken.

A fixing hole 54 is provided on the end surface of the piston rod 8, and the member to be operated is fixed to the piston rod 8 by the fixing hole 54.

According to the embodiment shown in FIG. 4, a cylinder cover 7 without a piston rod is fixed in the cylinder bore 2 in a different manner. In this case as well, the cylinder cover 7 is inserted into the enlarged part of the cylinder bore 2 and brought into contact with the ring-shaped additional part 17 in the same manner as described above.

Next, a part of the end face 56 of this cylinder 1 is flanged or bent. This cylinder 7, which is preferably beveled in the area of its outwardly facing edge 55, is thus held in a ring shape and
And it is crimped onto the ring-shaped additional portion 17.

In this embodiment as well, it is advantageous to perform a welding process to firmly and closely connect the flanged or bent portion to the cylinder cover 7.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing a first embodiment of a piston-cylinder unit according to the present invention, and FIG. 2 is a longitudinal cross-sectional view of the piston-cylinder unit taken along the - line in FIG. 3 is a front view of this piston-cylinder unit as seen in the direction of the arrow in FIG. 1, and FIG. 4 is a partial sectional view showing a particularly advantageous manner of fixing the cylinder cover. 1...Cylinder, 2...Cylinder perforation, 3...
...Piston, 4, 5...Cylinder chamber, 6,7...
Cylinder cover, 8... Piston rod, 9...
Outer circumferential surface, 10... Signal generator, 11... Axial guide, 12... Outer circumferential surface, 13... Guide groove, 14...
...Support leg, 15... Piston end face, 16... End face, 17... Ring-shaped additional part, 18... Surface, 2
2...Welding seam, 23...Cylinder end face, 24...
... Expansion section, 25 ... Holding protrusion, 26 ... Safety ring, 27 ... Circumferential groove, 28 ... Ring seal, 2
9...Radial edge, 30...Central portion, 31...
...Axial end, 32...Ring-shaped protrusion, 33...
...Drilling part, 34...Guide bush, 35...Corrugated seal ring, 36...Axial end, 37,3
7'... Stopper surface, 38... Magnet device,
39...Snat spring, 42...Outer peripheral surface, 43
...Retaining ridge, 44...Ring seal, 45...
...Ring magnet, 46...End face, 47...Centering addition part, 48...Ring magnet,
49, 49'... Connection hole, 50... Outer peripheral surface, 51
... Connection strip, 52 ... Cylinder corner range, 53 ... Perforation, 54 ... Fixing perforation, 5
5... Edge, 56... End face.

Claims (1)

[Claims] 1 Both axial ends 2 by cylinder covers 6 and 7
Cylinder 1 with 3 and 16 closed and cylinder 1
It consists of a piston 3 guided in an axially movable and sealed manner within the piston, a piston rod 8 connected to the piston 3 and passing through one cylinder cover 6, and a permanent magnet supported by the piston 3. A piston-cylinder unit, in particular in short-stroke cylinders, comprising a magnetic device 38 and at least one signal generator 10 arranged on the outer circumferential surface 9 of the cylinder 1 and actuable by the magnetic device 38, can be withdrawn from the cylinder 1. The cylinder 1 is made of a processed molded material, and on the outer circumferential surface 9 of the cylinder 1 there is provided a ring for axially slidably holding at least one signal generator 10 configured, for example, as a so-called reed switch. A piston cylinder unit characterized in that at least one axial guide 11 is provided that faces in the axial direction of the cylinder 1 and extends over the entire length thereof. 2 The cylinder 1 has a square or rectangular cross section, and a signal generator 1 is provided on each of the three outer walls or surfaces 12 of the cylinder 1.
an axial guide 11 for 0 is provided;
2. A piston-cylinder unit as claimed in claim 1, characterized in that the fourth outer wall surface 50 is constructed in such a way that a conduit or tube for pressure medium can be connected thereto. 3. The at least one axial guide 11 is designed as a guide groove 13, in which the signal generator 10 with sliding play is guided. A piston-cylinder unit according to range 1 or 2. 4. The piston cylinder unit according to claim 1 or 2, wherein at least one axial guide 11 is configured as a guide rail integrally formed with the cylinder outer wall surface. 5. According to any one of claims 1 to 4, wherein at least one axial guide 11 is formed directly on the cylinder by drawing a cylinder molded material. The piston cylinder unit described. 6. The cylinder cover 7, which does not have a piston rod on the side opposite to the piston 3, is constructed as a stamped part which is inserted immovably into the cylinder bore 2 on its end side, and which stamped part is attached to the cylinder in an irreleasable manner. A piston-cylinder unit according to any one of claims 1 to 5, characterized in that the piston-cylinder unit is coupled to a piston-cylinder unit. 7 Cylinder cover without piston rod 7
is joined to the cylinder 1 by a welding process such as ultrasonic welding or laser welding, or by a screwless method such as flanging the cylinder wall. The piston cylinder unit described. 8. The magnet device 38 has a magnet 45, and this cylinder magnet 45 is coaxially mounted on one of the piston end faces 15 or 46, or inserted into this end face. A piston cylinder unit according to any one of claims 1 to 7. 9. Claim 8, characterized in that the ring magnet 45 is bonded to the piston 3.
The piston cylinder unit described in section. 10. The piston cylinder unit according to claim 8 or 9, wherein the ring magnet 45 is disc-shaped. 11 The piston 3 has one piston end surface 1
It has a sleeve-shaped centering addition part 47 integrally molded coaxially with 5 or 46, and the ring magnet 45 attaches to this centering addition part 47.
The piston cylinder unit according to any one of claims 8 to 10, characterized in that the piston cylinder unit is fitted over the piston cylinder unit. 12. Claims characterized in that the centering addition part 47 is flanged outward in the semi-longitudinal direction so as to engage the ring magnet 45 from the rear in order to hold the ring magnet 45. The piston cylinder unit according to item 11. 13. The piston 3 supports a ring seal 44 along its outer peripheral surface 42, and in order to seal the piston 3 against the cylinder bore 2,
A piston cylinder unit according to any one of claims 1 to 12, characterized in that this ring seal 44 is used. 14. The ring seal 44 is molded integrally with the outer circumferential surface 42 of the piston 3 and is fitted over a ring-shaped retaining ridge 43 that projects radially from the piston 3. The piston cylinder unit according to item 13. 15 The outer peripheral surface of the ring magnet 45 protrudes in the radial direction from the outer peripheral surface 42 of the piston 3,
15. The piston-cylinder unit according to claim 14, wherein the piston-cylinder unit extends to just before the inner surface of the cylinder perforation. 16. Piston-cylinder unit according to any one of claims 1 to 15, characterized in that a ring magnet (45) is assigned to the end face (46) of the piston on the side facing the piston rod (3). 17. The piston cylinder unit according to any one of claims 8 to 16, wherein the ring magnet 45 is made of an oxide magnet. 18 When the cylinder 1 is drawn, a connecting strip 51 is formed integrally with the outer peripheral surface 50 of the cylinder 1 and extends in the axial direction of the cylinder 1 over the entire length of the cylinder.
18. Piston-cylinder unit according to any one of claims 1 to 17, characterized in that the piston-cylinder unit is provided for a conduit or tube for pressure medium or the like. 19 The connecting strip 51 has two connecting holes 49, 49' provided in the area of the two cylinder covers 6, 7 for fixing pressure medium conduits or tubes or the like. The connecting holes 49, 49' are connected to the two cylinder chambers 4, which are divided by the piston 3 inside the cylinder 1.
19. The piston-cylinder unit according to claim 18, characterized in that each of the piston-cylinder units communicates with one of the pistons and cylinders. 20. The piston cylinder unit according to any one of claims 1 to 19, characterized in that the piston 3 is releasably screwed onto the piston rod 8.