Working cylinder

Abstract

A cylinder has first and second coupling partners. The first coupling partner is a cylindrical tube. The second coupling partner is a closing element. One coupling partner is inserted axially into the other coupling partner. Each of the coupling partners has an annular groove. The groove of the inserted coupling partner is an external groove. The groove of the remaining coupling partner is an internal groove and the grooves of the coupling partners lie opposite one another. The working cylinder includes a spring-loaded coupling ring, and which when deformed in a tensioning direction, can be fully accommodated by the groove of one coupling partner and which, when deformed in the release direction, engages in the grooves of both coupling partners. The inserted coupling partner is oversized in relation to the remaining coupling partner and provides a additional frictional connection.

Claims

1. A working cylinder, comprising: a first coupling partner being a cylinder barrel and a second coupling partner being a closure element, said first coupling partner and said second coupling partner being inserted axially into one another; said first and second coupling partners each having a respective annular groove formed therein, said annular groove of an inserted coupling partner of said first and second coupling partners being an external groove and said annular groove of a remaining coupling partner being an internal groove, said annular grooves of said first and second coupling partners being disposed opposite one another; and a coupling ring for being resiliently braced, said coupling ring, when deformed in a bracing direction, being fully received in said annular groove of one of said first and second coupling partners and said coupling ring, when deformed in a relaxation direction, engaging into said annular grooves of said first and second coupling partners in an engagement, the engagement of said coupling ring into said annular grooves of said first and second coupling partners effecting a positively locking connection between said first and second coupling partners; said inserted coupling partner having an oversize in relation to an internal diameter of said remaining coupling partner, for providing an interference fit effecting a non-positively locking connection between said first and second coupling partners; a hybrid coupling action produced by said interference fit and said coupling ring, said hybrid coupling action including a frictional locking between said first and second coupling partners resulting from said interference fit for axially and rotationally locking said first and second coupling partners to one another, said coupling ring for accommodating axial forces acting on said first and second coupling partners; said interference fit being set to an interference allowing said first and second coupling partners to move into a clearance end position of said coupling ring with said coupling ring engaged by opposing axial side walls of said annular grooves when a full operating pressure is applied to the working cylinder, said interference fit being set to an interference that preventing an axial return movement out of said clearance end position and maintaining said end position under load alternation of the working cylinder.

2. The working cylinder according to claim 1, wherein said second coupling partner is insertable into said first coupling partner, said coupling ring is fully received by said annular groove of said second coupling partner.

3. The working cylinder according to claim 1, wherein said second coupling partner has an overhang, said overhang engages in sections over said first coupling partner at an outer lateral surface thereof.

4. The working cylinder according to claim 1, wherein said coupling ring or said coupling partner which does not fully receive the coupling ring has a run-on bevel, said run-on bevel causes said coupling ring to be fully received in said respective annular groove of said coupling partner which fully receives the coupling ring.

5. The working cylinder according to claim 1, wherein said first and second coupling partners have further, axially offset annular grooves to receive further, axially offset coupling rings.

6. The working cylinder according to claim 1, wherein said coupling ring has a circular cross section.

7. The working cylinder according to claim 1, wherein said first and the second coupling partners have different moduli of elasticity, a first area of overlap between said engaged coupling ring and a side wall of said annular groove of one of said coupling partners, which has the higher modulus of elasticity, is smaller than a second area of overlap between said coupling ring and a side wall of said annular groove of the other coupling partner, which has a lower modulus of elasticity.

8. The working cylinder according to claim 1, wherein said coupling ring is of conical and segmented form.

9. The working cylinder according to claim 1, wherein said annular groove in said coupling partner which fully receives the coupling ring is provided with an elastic element which acts radially on the coupling ring.

10. The working cylinder according to claim 1, wherein said remaining coupling partner has radially arranged access openings, said access openings permit manipulation of said coupling ring from an outside thereof.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) The invention will be explained in more detail below, on the basis of exemplary embodiments, with reference to:

(2) FIG. 1 which shows a sectional illustration of a working cylinder with a coupling ring,

(3) FIG. 2 which shows a half-section of a working cylinder with two coupling rings,

(4) FIG. 3 which shows a half-section of a working cylinder with circular coupling ring cross section,

(5) FIG. 4 which shows a half-section of a working cylinder with circular coupling ring cross section and an overhang,

(6) FIG. 5 which shows a half-section of a working cylinder with a conical coupling ring,

(7) FIG. 6 which shows a half-section of a working cylinder with a conical coupling ring and an elastic element,

(8) FIG. 7 which shows a sectional illustration of a working cylinder with access openings, in plan view, and

(9) FIG. 8 which is a detail illustration of the coupling partners in a clearance end position.

DESCRIPTION OF THE INVENTION

(10) FIG. 1 shows a working cylinder according to the invention in a full section.

(11) The working cylinder is of multi-part form and has a cylinder barrel 1 and a closure element 2, wherein the closure element 2 has been partially inserted into the cylinder barrel 1.

(12) According to the invention, the cylinder barrel 1 and closure element 2 are coupled to one another by means of a positively locking connection.

(13) The positively locking connection is in the present case achieved by virtue of a coupling ring 4.1 being arranged within the working cylinder.

(14) In the present case, the coupling ring 4.1 has a rectangular cross section, wherein according to the invention, coupling rings with other forms of cross section may also be used.

(15) To receive the coupling ring 4.1, the cylinder barrel 1 and the closure element 2 have in each case a first annular groove 3.1 and 3.3, wherein the first annular groove 3.1 of the cylinder barrel 1 is in the form of an encircling internal groove and the first annular groove 3.3 of the closure element 2 is in the form of an encircling external groove.

(16) The first annular groove 3.3 of the closure element 2 is, in the present exemplary embodiment, designed such that it can receive the coupling ring 4.1 fully, and in particular to such an extent as to ensure that the closure element 2 can be inserted into the cylinder barrel 1 without complications.

(17) As the closure element 2 is inserted into the cylinder barrel 1, the coupling ring 4.1 is pushed into the first annular groove 3.3 of the closure element 2 and, in the process, is braced in its bracing direction.

(18) When the closure element 2 reaches its final assembled position in the cylinder barrel 1, with the annular grooves 3.1 and 3.3 being situated correspondingly opposite one another, it is made possible for the coupling ring 4.1 to relax in its relaxation direction, enabling the coupling ring 4.1 to engage simultaneously into the annular grooves 3.1 and 3.3.

(19) The positive locking of the coupling of the cylinder barrel 1 and of the closure element 2 is realized according to the invention in that, in the final position of the closure element 2 in the cylinder barrel 1, that surface of the coupling ring 4.1 which faces toward the closure element-side end of the cylinder barrel 1 bears against those walls of the annular grooves 3.1 and 3.3 which face toward the coupling ring 4.1.

(20) The closure element 2 is thus prevented in an effective manner from possibly being pulled out of the cylinder barrel 1, in particular during use of the working cylinder.

(21) Furthermore, a working cylinder according to the invention has a sealing element 10 by means of which an escape of a working medium from the working cylinder is prevented in the region of the coupling between the cylinder barrel 1 and closure element 2.

(22) In order that, as the closure element 2 is inserted into the cylinder barrel 1, the coupling ring 4.1 is pushed into the annular groove 3.3 of the closure element 2 and, at the same time, damage to the sealing element 10 is prevented, the cylinder barrel 1 additionally has, on the end facing toward the closure element 2, a run-on bevel 7 of encircling form.

(23) In order that, as the closure element 2 is inserted further into the cylinder barrel 1, damage to the sealing element 10 is also prevented as it passes over the annular groove 3.1 of the cylinder barrel 1, the annular groove 3.1 also has an annular groove bevel 9, which is also required at the same time if multiple coupling rings are used in parallel but with an axial spacing to one another.

(24) As a particular technological feature of the present working cylinder, the external diameter of the closure element 2 has an oversize in relation to the internal diameter of the cylinder barrel 1.

(25) The oversize has the effect that, in the final assembled position of the closure element 2, an interference fit and thus frictional locking is produced between said closure element and the cylinder barrel 1.

(26) Owing to the frictional locking that is provided, the closure element 2 and the cylinder barrel 1 are fixed axially in their position relative to one another without a clearance, whereby the closure element 2 is prevented in an effective manner from moving axially relative to the cylinder barrel 1.

(27) In this way, so-called abrasion grinding phenomena on the sealing element 10 can be avoided, such as can otherwise occur in particular in the event of working cylinder load alternation and resulting slight movements of the closure element 2 relative to the cylinder barrel 1.

(28) In the prior art, such slight movements between the closure element and cylinder barrel can arise owing to the fact that the annular grooves which receive the coupling ring must have a defined oversize in relation to the coupling ring in order to enable the coupling ring to assume its final position in the annular grooves when the closure element reaches its end position in the cylinder barrel.

(29) For illustration, reference is made in this regard to FIG. 8, which shows, in a detail view, the coupling partners 1 and 2 in their clearance end positions and the coupling ring 4.1 in its final position in the annular grooves 3.1 and 3.3 and the oversize of the annular grooves 3.1 and 3.3 in relation to the coupling ring 4.1.

(30) Here, FIG. 8 shows an embodiment of the working cylinder in which the annular grooves 3.1 and 3.3 do not have a run-on bevel. FIG. 8 shows the relative position assumed by the cylinder barrel 1 and closure element 2 owing to the load in a clearance end position.

(31) As a further advantage, the frictional locking that is provided makes it possible for axially acting forces when the working cylinder is subjected to load to be accommodated and for undesired twisting of the closure element 2 relative to the cylinder barrel 1 to be prevented.

(32) In particular, owing to the additional accommodation of axial forces by way of the frictional locking, the maximum load and endurance strength of the working cylinder can be optimized.

(33) FIG. 2 shows an exemplary embodiment of a working cylinder according to the invention in half-section, wherein, to increase the axial load-bearing capacity, the working cylinder has two coupling rings 4.1 and 4.2.

(34) In the present case, the coupling ring 4.1 is arranged in a first annular groove 3.1 of the cylinder barrel 1 and in a first annular groove 3.3 of the closure element 2.

(35) By contrast, the coupling ring 4.2 is arranged in a second annular groove 3.2 of the cylinder barrel 1 and in a second annular groove 3.4 of the closure element 2.

(36) To ensure complete insertion of the closure element 2 into the cylinder barrel 1, an annular groove bevel 9 is provided on the annular groove 3.1 of the cylinder barrel 1.

(37) Said annular groove bevel 9 has the effect, in a particularly advantageous manner, that the second coupling ring 4.2, after it relaxes into the annular groove 3.1, is pushed back by the annular groove bevel 9 into the annular groove 3.3 of the closure element 2 again, and thus the insertion of the closure element 2 into the cylinder barrel 1 can be continued.

(38) Furthermore, in the present exemplary embodiment as per FIG. 2, the sealing element 10 is arranged in the region of the run-on bevel 7 of the cylinder barrel 1.

(39) The arrangement of the sealing element 10 in said region has the advantage in particular that no additional installation space has to be provided in the cylinder barrel 1 or in the closure element 2 for receiving the sealing element 10. The production outlay for a working cylinder according to the invention can thus be reduced.

(40) In a further exemplary embodiment as per FIG. 3, the coupling ring 4.1 has a circular cross section.

(41) Such a circular cross section is, in a particularly advantageous manner, associated with a reduction in production costs for the coupling ring 4.1 and with an optimization of the profile of the internal stresses in the coupling ring 4.1 during the bracing thereof.

(42) To realize as large a region as possible in which there is a positive locking action between the coupling ring 4.1 and the annular groove 3.1 of the cylinder barrel 1, said annular groove is adapted in terms of its contour to the cross-sectional geometry of the coupling ring 4.1.

(43) The adaptation of the annular groove contour to the cross section of the coupling ring 4.1 furthermore has the technological advantage that, owing to the resulting roundings of the annular groove contour, notch effects that arise when the positively locking connection is subjected to load can be substantially eliminated.

(44) FIG. 4 shows a further exemplary embodiment of a working cylinder according to the invention.

(45) In relation to the variant from FIG. 3, the closure element 2 in this case additionally has an overhang 5 which hangs over the external lateral surface 6 of the cylinder barrel 1.

(46) It has been found that, through the provision of the overhang 5, when an internal pressure prevails in the cylinder barrel 1, an outwardly directed deformation of the cylinder barrel 1 can be counteracted in the region of the overhang 5, whereby the fit conditions between the coupled parts, that is to say the coupling partners 1 and 2, do not change in the operational load state.

(47) Thus, in the case of a non-positively locking interference-fit connection being provided between the cylinder barrel 1 and the closure element 2, the overhang 5 has the special technological advantage that the non-positively locking connection is not released, such as can occur under some circumstances under the action of internal pressures prevailing in the cylinder barrel 1.

(48) Thus, the overhang 5 has the effect in particular of positively influencing the endurance strength of a working cylinder according to the invention.

(49) As a further exemplary embodiment, FIG. 5 shows a working cylinder according to the invention with a coupling ring 4.1 which is of conical form and which has multiple segments.

(50) In this case, the annular grooves 3.1 and 3.3 are of a geometrical form such that, when the closure element 2 reaches the final assembled position in the cylinder barrel 1, the segments of the coupling ring 4.1 at least partially pivot into the annular groove 3.1 of the cylinder barrel 1.

(51) FIG. 6 shows a refinement of the working cylinder as per the exemplary embodiment from FIG. 5.

(52) In this case, a working cylinder as per FIG. 6 additionally has an elastic element 8 which, according to the invention, is arranged in the annular groove 3.3 of the closure element 2.

(53) According to the invention, the elastic element 8 acts radially on the coupling ring 4.1 and thus assists the relaxation thereof when the closure element 2 reaches the final position in the cylinder barrel 1.

(54) Furthermore, the elastic element 8 ensures correct seating of the coupling ring 4.1 in the annular grooves 3.1 and 3.3 even in the event of insufficient relaxation of the coupling ring 4.1.

(55) According to the invention, the elastic element 8 may for example be formed by an elastomer element with circular cross section or by a similarly shaped rubber element.

(56) Furthermore, depending on the application, use may also be made of elastic elements with other cross sections.

(57) FIG. 7 shows a further exemplary embodiment of a working cylinder according to the invention in a sectional plan view.

(58) In this case, the exemplary embodiment as per FIG. 7 provides that, in the cylinder barrel 1, access openings 11 are provided which make it possible for the coupling ring 4.1 to be manipulated from the outside for example by means of a suitable tool (not illustrated) or a screw (not illustrated). The access openings are preferably each arranged with a 120-degree offset.

(59) By means of such external manipulation of the coupling ring 4.1, it is possible for said coupling ring to be pushed back into the annular groove 3.3 of the closure element 2 again, and thus for the engagement of the coupling ring 4.1 into the annular groove of the cylinder barrel 1 to be eliminated, in a particularly advantageous manner.

(60) Thus, as a special technological advantage, a releasable connection between the cylinder barrel 1 and the closure element 2 is provided.

(61) In a particularly advantageous embodiment, the access openings 11 may be provided with a thread into which a screw (not illustrated) can be screwed, which screw in turn causes the coupling ring 4.1 to be pushed back into the annular groove 3.1 of the closure element 2.

REFERENCE NUMERALS USED

(62) 1 Cylinder barrel 2 Closure element 3.1 First annular groove, cylinder barrel 3.2 Second annular groove, cylinder barrel 3.3 First annular groove, closure element 3.4 Second annular groove, closure element 4.1 First coupling ring 4.2 Second coupling ring 5 Overhang 6 Lateral surface 7 Run-on bevel 8 Elastic element 9 Annular groove bevel of the first annular groove, closure element 10 Sealing element 11 Access openings