EP3322903B1 - Double-acting hydraulic cylinder - Google Patents

Description

The invention relates to a double-acting hydraulic cylinder with a first connection for charging a first pressure chamber with a hydraulic fluid and a second connection for charging a second pressure chamber with the hydraulic fluid.

Double-acting hydraulic cylinders are known from the prior art. Figure 8a shows an exemplary schematic diagram of a double-acting hydraulic cylinder 100 according to the prior art. The well-known hydraulic cylinder 100 after Figure 8a comprises a cylinder housing 102 and a piston 104 guided in the cylinder housing 102. The cylinder housing 102 comprises a first pressure chamber 106 formed by the cylinder housing 102 and a second pressure chamber 108 formed by the cylinder housing 102. The first pressure chamber 106 and the second pressure chamber 108 are connected by the Pistons 104 separated from each other. The first pressure chamber 106 is also referred to as cylinder chamber A, while the second pressure chamber 108 is also referred to as cylinder chamber B.

As in Figure 8a shown, the cylinder chambers 106, A, and 108, B must be connected to a supply unit/control unit 110, which supplies the hydraulic cylinder 100 with a liquid or gaseous medium. The connection between the supply unit/control unit 110 and the connection 112 or 114 on the cylinder housing 102 is made via a flexible hose 116, 118. Typically, a pressed ring eye 120 made of metal, a hollow screw 122 and two seals 124, 126 are attached to the respective end of the hose , like it in Figure 8c is shown schematically. In Figure 8c 12 is a schematic representation of an exposed banjo bolt 122 of the known hydraulic cylinder 100 according to FIG Figure 8a shown. For use with operating tables, a hose 116, 118 with a nominal diameter of DN 3 and DN 4 is typically used. Furthermore, the screw connection has a height L1 from the outer surface of the cylinder housing 102 to the end of the hollow screw 122 of approximately 15 mm. The hoses 116, 118 are necessary if the in Figure 8a shown cylinder 100 is movably mounted.

Figure 8b shows a schematic representation of a double-acting hydraulic cylinder 200 according to the prior art. In Figure 8b In particular, a spare parts picture of the double-acting hydraulic cylinder 200 of the CSH1 MF3, MF4, MT4 and MS2 series according to the Bosch Rexroth catalog with the catalog number RD17332/07.13 is shown. In the case of double-acting hydraulic cylinders, the A-side, ie on the piston side, and on the B-side, ie on the piston rod side, each have a connection for a liquid medium. Mostly this will be like in Figure 8b shown, realized by a connection bore 212, 214 in the housing of the double-acting hydraulic cylinder 200.

The well-known, double-acting hydraulic cylinders have the disadvantage that, if the Figure 8a shown cylinder housing 102 with the hose connections 112, 114 is used in tight spaces, which in Figure 8c shown hollow screw 122 is very exposed and disturbing at the respective end of the hose. This is particularly disadvantageous in that approximately 15 mm of installation space is lost in the length or width of the hydraulic cylinder. Furthermore, the known, double-acting hydraulic cylinders have the disadvantage that the exposed banjo bolt 122 can easily shear off on nearby components in the moving hydraulic cylinders due to the high cylinder forces during the displacement movement. In addition, the in Figure 8a shown hose connections 116, 118 relatively susceptible to damage in the known, double-acting hydraulic cylinders.

the WO 9110810 A1 , JP S62 204003 U , DE 10 2007 048907 A1 , JP S63 104704 U , GB 937765A , DE 10 2005 061730 A1 disclose known double acting hydraulic cylinders.

Proceeding from the known state of the art, it is the object of the invention to specify a double-acting hydraulic cylinder which has a compact and robust design and at the same time enables reliable operation of the same.

This problem is solved by a double-acting hydraulic cylinder with the features of claim 1. Advantageous developments are specified in the dependent claims.

A double-acting hydraulic cylinder with the features of claim 1 achieves a compact and robust design of the double-acting hydraulic cylinder and at the same time reliable operation of the same, since in particular a first cylinder housing, a piston guided in the first cylinder housing and a second cylinder housing are provided. A first pressure chamber and a second pressure chamber are provided in the first cylinder housing and are separated from one another by the piston. A first connection is used at least to supply hydraulic fluid to the first pressure chamber, while a second connection is used at least to supply hydraulic fluid to the second pressure chamber. The second cylinder housing surrounds the first cylinder housing at least in one section. The first connection and the second connection are arranged on an end of the double-acting hydraulic cylinder that faces away from the second pressure chamber. The second pressure chamber can be acted upon by the hydraulic fluid via the section in which the second cylinder housing surrounds the first cylinder housing. Thus, on the connection on the B-side of the double-acting hydraulic cylinder can be dispensed with. Instead, this connection can be provided on the A-side of the double-acting hydraulic cylinder. The A side is located on a first side of the piston, while the B side is located on a second side of the piston opposite the first side.

As a result, a relatively large installation space for the double-acting hydraulic cylinder can be avoided. Furthermore, shearing of an exposed connection element, e.g. B. an exposed banjo bolt, are avoided. In addition, damage to the connection hoses, which extend between the connections of the double-acting hydraulic cylinder and the supply/control unit (such as a hydraulic unit), can be prevented during operation of the double-acting hydraulic cylinder. This enables the compact and robust construction of the double-acting hydraulic cylinder and, at the same time, the reliable operation of the same.

According to the invention, the second cylinder housing surrounds the first cylinder housing at least in a section along the longitudinal axis of the double-acting hydraulic cylinder. Thus, a section in which the second cylinder housing surrounds the first cylinder housing can be provided, which section extends along the longitudinal axis of the double-acting hydraulic cylinder.

According to the invention, the end of the double-acting hydraulic cylinder facing away from the second pressure chamber is delimited by a cylinder base. The cylinder base encloses an end of the first cylinder housing which is remote from the second pressure chamber and an end of the second cylinder housing which is remote from the second pressure chamber. Thus, the ends of the first and second cylinder housings on the piston side facing away from the second pressure chamber can be firmly connected to the cylinder base.

According to the invention, the first connection and the second connection are arranged on the cylinder base. Thus, both the first connection and the second connection can be provided on an end of the double-acting hydraulic cylinder that faces away from the second pressure chamber.

According to the invention, the first connection comprises a first through opening. Furthermore, the first through hole extends from a side surface of the cylinder bottom to the first pressure chamber. A first passage opening can thus be provided in the cylinder base, via which the first pressure chamber can be acted upon by the hydraulic fluid.

The first pressure chamber is preferably a pressure chamber on the piston side, while the second pressure chamber is a pressure chamber on the piston rod side. In this case, the hydraulic cylinder is in particular a differential cylinder. A pressure chamber on the piston side and a pressure chamber on the piston rod side of a differential cylinder can thus be provided, each of which is formed by the first cylinder housing.

A first sealing element is preferably arranged between the end of the first cylinder housing facing away from the second pressure chamber and the cylinder base. Furthermore, a second sealing element is arranged between the end of the second cylinder housing facing away from the second pressure chamber and the cylinder base. A first and second sealing element can thus be provided, with the aid of which the end of the first cylinder housing facing away from the second pressure chamber or the end of the second cylinder housing facing away from the second pressure chamber and the cylinder base can be sealed from one another.

Preferably, the second port includes a second through hole. Further, the second through hole extends from a side surface of the cylinder bottom to the portion where the second cylinder case surrounds the first cylinder case. A second passage opening can thus be provided in the cylinder base, via which the second pressure chamber can be acted upon by the hydraulic fluid.

Preferably, the first cylinder case and the second cylinder case are arranged such that a clearance is formed between the first cylinder case and the second cylinder case. The intermediate space extends from the end of the double-acting hydraulic cylinder that faces away from the second pressure chamber to an end of the double-acting hydraulic cylinder that faces away from the first pressure chamber. Thus, an intermediate space can be provided between the first and second cylinder housing, this intermediate space being used to connect the second pressure chamber to the second port on the second pressure chamber opposite end of the double-acting hydraulic cylinder.

Preferably, the double-acting hydraulic cylinder includes a rod bushing. The rod bushing is arranged on an end of the first and second cylinder housing that faces away from the first pressure chamber. Furthermore, the rod bushing is designed in such a way that a piston rod connected to the piston moves when the first pressure chamber is acted upon by the hydraulic fluid in a first piston movement direction and when the second pressure chamber is acted upon by the hydraulic fluid in a second piston movement direction opposite to the first piston movement direction. Thus, at the end of the double-acting hydraulic cylinder on the piston rod side, a rod bushing can be provided, which closes an end of the hydraulic cylinder facing away from the first pressure chamber.

Preferably, the rod bushing includes a recess. Furthermore, the hydraulic fluid can be applied to the second pressure chamber via the section in which the second cylinder housing surrounds the first cylinder housing and via the recess in the rod bushing. The pressure chamber on the piston rod side can thus be pressurized with the hydraulic fluid easily and reliably with the aid of the second connection, which is provided on the piston-side end of the double-acting hydraulic cylinder.

Preferably, the first cylinder housing includes a first cylinder tube and the second cylinder housing includes a second cylinder tube. Thus, in particular, a simple and robust construction of the double-acting hydraulic cylinder can be implemented.

The double-acting hydraulic cylinder preferably comprises at least one first holding element for holding the second cylinder housing. Furthermore, the at least one first holding element is arranged at least in sections around the second cylinder housing on an outer surface of the second cylinder housing. The first and second cylinder housings can thus be held easily and securely on the cylinder base with the aid of the at least one first holding element.

The first connection is preferably designed in such a way that it can be connected to a first connecting line at least for supplying the hydraulic fluid. Furthermore, the second connection is designed in such a way that it can be connected to a second connecting line at least for supplying the hydraulic fluid. Thus, two suitable connections can be provided for connection to a hydraulic unit.

The double-acting hydraulic cylinder can in particular be a differential cylinder, synchronous cylinder or tandem cylinder.

Further features and advantages of the invention result from the following description, which explains the invention in more detail using exemplary embodiments in connection with the attached figures.

Figur 1a

eine schematische, perspektivische Ansicht eines doppeltwirkenden Hydraulikzylinders gemäß einem Ausführungsbeispiel;

Figur 1b

eine schematische Draufsicht auf den doppeltwirkenden Hydraulikzylinder nach Figur 1a;

Figur 2

eine schematische Längsschnittdarstellung entlang der Schnittlinie A-A in Figur 1b;

Figur 3

eine schematische Längsschnittdarstellung entlang der Schnittlinie B-B in Figur 1b;

Figur 4a

eine schematische Längsschnittdarstellung entlang der Schnittlinie C-C in Figur 1b;

Figur 4b

eine schematische Darstellung eines kolbenseitigen Endes des in Figur 1a gezeigten doppeltwirkenden Hydraulikzylinders;

Figur 5

eine beispielhafte Prinzipskizze eines doppeltwirkenden Hydraulikzylinders, der nicht durch die Ansprüche gedeckt ist.

Figur 6a

eine schematische Darstellung eines doppeltwirkenden Hydraulikzylinders mit einem ersten Anschluss und einem zweiten Anschluss gemäß einem Ausführungsbeispiel;

Figur 6b

eine schematische Darstellung eines doppeltwirkenden Hydraulikzylinders mit einem Anschluss an der B-Seite des doppeltwirkenden Hydraulikzylinders gemäß dem Stand der Technik;

Figur 7a

eine schematische Längsschnittdarstellung eines doppeltwirkenden Hydraulikzylinders gemäß einem Ausführungsbeispiel;

Figur 7b

eine schematische Längsschnittdarstellung eines doppeltwirkenden Hydraulikzylinders mit einer exponierten Hohlschraube gemäß dem Stand der Technik;

Figur 8a

eine beispielhafte Prinzipskizze eines doppeltwirkenden Hydraulikzylinders gemäß dem Stand der Technik;

Figur 8b

eine schematische Darstellung eines doppeltwirkenden Hydraulikzylinders gemäß dem Stand der Technik; und

Figur 8c

eine schematische Darstellung einer exponierten Hohlschraube des bekannten, doppeltwirkenden Hydraulikzylinders nach Figur 8a.

Show it:

Figure 1a

a schematic, perspective view of a double-acting hydraulic cylinder according to an embodiment;

Figure 1b

a schematic top view of the double-acting hydraulic cylinder Figure 1a ;

figure 2

a schematic longitudinal sectional view along the section line AA in Figure 1b ;

figure 3

a schematic longitudinal sectional view along the section line BB in Figure 1b ;

Figure 4a

a schematic longitudinal sectional view along section line CC in Figure 1b ;

Figure 4b

a schematic representation of a piston-side end of the in Figure 1a shown double-acting hydraulic cylinder;

figure 5

an exemplary schematic diagram of a double-acting hydraulic cylinder, which is not covered by the claims.

Figure 6a

a schematic representation of a double-acting hydraulic cylinder with a first connection and a second connection according to an embodiment;

Figure 6b

a schematic representation of a double-acting hydraulic cylinder with a connection on the B-side of the double-acting hydraulic cylinder according to the prior art;

Figure 7a

a schematic longitudinal sectional view of a double-acting hydraulic cylinder according to an embodiment;

Figure 7b

a schematic longitudinal sectional view of a double-acting hydraulic cylinder with an exposed hollow screw according to the prior art;

Figure 8a

an exemplary schematic diagram of a double-acting hydraulic cylinder according to the prior art;

Figure 8b

a schematic representation of a double-acting hydraulic cylinder according to the prior art; and

Figure 8c

a schematic representation of an exposed banjo bolt of the known, double-acting hydraulic cylinder Figure 8a .

Figure 1a shows a schematic, perspective view of a double-acting hydraulic cylinder 10 according to an embodiment. In Figure 1a In particular, a double-walled cylinder is shown in a cut-open view. As in Figure 1a 1, the double-acting hydraulic cylinder 10 includes a first cylinder tube 14, a second cylinder tube 16, and a piston 26. The piston 26 is connected to a piston rod 24. As shown in FIG. The longitudinal axis 30 of the double-acting hydraulic cylinder 10 extends through a midpoint of the piston rod 24 along a longitudinal extent of the piston rod 24. The first and second cylinder tubes 14, 16 are arranged concentrically around this longitudinal axis 30 of the double-acting hydraulic cylinder 10.

At the in Figure 1a In the exemplary embodiment shown, the first cylinder tube 14 is provided, on which the piston 26 slides in a sealed manner and generates the force of the actuator. Furthermore, the second cylinder tube 16 is arranged around this first cylinder tube 14 . A first end of the second cylinder tube 16 on the piston rod side is tightly connected to a rod bushing 22 . A second end of the cylinder tube 16 opposite the first end is tightly connected to a cylinder base 12 . The first cylinder tube 14 serves as an inner cylinder tube, while the second cylinder tube 16 serves as an outer cylinder tube. The second cylinder tube 16 is held on the cylinder base 12 via a wire ring 20a and an annular holding element 20b with the aid of screws 46a to 46d. The cylinder base 12 and the annular holding element 20b form one section of the double-acting hydraulic cylinder 10. The second cylinder tube 16 is sealed against this section. In the sectional view Figure 1a the screw 46d is not shown.

According to Figure 1a the double-acting hydraulic cylinder 10 includes a connection 34 for applying a hydraulic fluid to a pressure chamber 38 on the piston rod side. As in Figure 1a shown, this connection 34 is provided in the cylinder base 12 . The connection 34 arranged in the cylinder base 12 is preferably connected to the intermediate space 40 between the first and second cylinder tubes 14, 16 via bores. Furthermore, the closure 22 arranged on the piston rod-side end of the double-acting hydraulic cylinder 10 with a piston rod passage comprises a groove 42. This closure 22 can also be referred to as a rod bushing. At the in Figure 1a The embodiment shown is introduced into the pressure chamber 38 on the piston rod side via this groove 42 in the rod bushing 22 . Thus, via the connection 34 arranged in the cylinder base 12 , the pressure chamber 38 on the piston rod side, ie the B side of the double-acting hydraulic cylinder 10 , can be charged with the hydraulic fluid or hydraulic fluid can be discharged from the pressure chamber 38 . Furthermore, the in Figure 1a The double-acting hydraulic cylinder 10 shown has a connection 32 for applying the hydraulic fluid to the pressure chamber 36 on the piston side and for draining hydraulic fluid from this pressure chamber. This connection 32 and the pressure chamber 36 on the piston side are in Figure 1a not shown. For installation in a cylindrical bore, the outside diameter formed by the second cylinder tube 16 is the relevant variable.

Figure 1b shows a schematic plan view of the double-acting hydraulic cylinder 10 after Figure 1a . In Figure 1b In particular, the cylinder base 12 is shown schematically with the screws 46a to 46d extending through the cylinder base 12. Figure 1b 12 is used to show first through third intersection lines 48a, AA, 48b, BB, and 48c, CC, with respect to cylinder head 12. The following figures 2 , 3 and 4a are sectional views of sections along the in Figure 1b shown first to third cutting lines 48a to 48c.

figure 2 shows a schematic sectional representation of a longitudinal section along the section line 48a, AA in Figure 1b . In the schematic sectional view figure 2 are essentially the elements 12 to 44 of the double-acting hydraulic cylinder 10 after Figure 1a clearly visible. the inside Figure 1a The connection 34 shown for applying hydraulic fluid to and discharging the pressure chamber 38 on the piston rod side is in figure 2 not visible. According to figure 2 the double-acting hydraulic cylinder 10 includes the first cylinder tube 14 and the one guided in the first cylinder tube 14 Piston 26. The first cylinder tube 14 preferably comprises the piston-side pressure chamber 36 formed by the first cylinder tube 14 between the piston 26 and the first end, opposite the piston rod 24, of the cylinder tube 14 closed by the cylinder base 12 and the piston-rod-side pressure chamber 38 formed by the first cylinder tube 14 between the piston 26 and the second end of the cylinder tube 14 closed by the rod bushing 22. The pressure chamber 36 on the piston side and the pressure chamber 38 on the piston rod side are separated from one another by the second piston 26. The second end of the first cylinder tube 14 closed with the aid of the rod bushing 22 is also referred to as the end on the piston rod side, and the second end of the cylinder tube 14 closed with the aid of the cylinder base 12 is also referred to as the end on the piston side.

As in figure 2 shown, a first sealing element 18a is arranged between the piston-side end of the first cylinder tube 14 and the cylinder base 12 . Furthermore, a second sealing element 18b is arranged between the piston-side end of the second cylinder tube 16 and the cylinder base 12 . In addition, a third sealing element 18c can be provided, which is arranged between the end of the second cylinder tube 16 on the piston rod side and the rod bushing 22 . Preferably, the first to third sealing elements 18a to 18c comprise a static sealing element, such as. B. an O-ring. Thus, in particular, the second cylinder tube 16 can be reliably sealed against the cylinder base 12 or the rod bushing 22 at its piston-side and piston-rod-side ends.

Furthermore, in figure 2 shown that the double-acting hydraulic cylinder 10 comprises a first and second screw connection 28a, 28b. The first screw connection 28a serves to connect the piston 26 to the piston rod 24, while the second screw connection 28b serves to connect a unit on the piston rod side to the piston rod 24. Preferably, the first and second screw connection 28a, 28b comprise a thread, which is arranged on the piston-side or piston-rod-side end of the piston rod 24. The rod bushing 22 serves to receive the piston rod 24. The rod bushing 22 also serves to linearly guide the piston rod 24 and the piston 26 connected to the piston rod 24. As in FIG figure 2 shown schematically, the piston rod 24 or the piston 26 is linearly displaced in a first piston movement direction P1 when the pressure chamber 36 on the piston side is acted upon by the hydraulic fluid. Furthermore, the piston rod 24 or the piston 26 is linearly displaced in a second piston movement direction P2 when the pressure chamber 38 on the piston rod side is acted upon by the hydraulic fluid. Preferably, the first and second piston movement directions are P1, P2 essentially parallel to the longitudinal axis 30 of the double-acting hydraulic cylinder 10. Furthermore, the first and second piston movement directions P1, P2 represent opposite piston movement directions of the double-acting hydraulic cylinder 10.

In figure 2 shows that the second cylinder tube 16 surrounds the first cylinder tube 14 at least in a section 41 . According to figure 2 this section 41 extends along the longitudinal axis 30 of the double-acting hydraulic cylinder 10. The intermediate space 40 formed by the first and second cylinder tubes 14, 16 extends essentially within this section 41. Furthermore, the intermediate space 40 extends essentially from the cylinder base 12 to the Groove 42 provided in the rod bushing 22. The groove 42 corresponds in particular to a recess in the rod bushing 22, which extends from the intermediate space 40 to the pressure chamber 38 on the piston rod side. Thus, the intermediate space 40, the recess 42 of the rod bushing 22 and the pressure chamber 38 on the piston rod side are connected to one another. In the figure 2 The dimension D1 shown is given by an outer surface 44 of the second cylinder tube 16 . This dimension D1 corresponds to an installation space for the double-acting hydraulic cylinder 10. figure 3 shows a schematic longitudinal sectional view along section line 48b, BB, in Figure 1b . In figure 3 In particular, the first connection 32 for pressurizing the pressure chamber 36 on the piston side is clearly visible. As in figure 3 shown schematically, the first connection 32 comprises a first through-opening 33. According to the invention, this first through-opening 33 extends from a lateral surface 62 of the cylinder base 12 to the pressure chamber 36 on the piston side. According to the invention, the first through-opening 33 extends essentially perpendicularly to the lateral surface 62 of the Cylinder base 12. The first connection 32 is used to connect a first connecting line 52. This first connecting line 52 is in figure 3 not shown.

Figure 4a shows a schematic longitudinal sectional view along section line 48c, CC, in Figure 1b . In particular, in Figure 4a the second connection 34 for pressurizing the pressure chamber 38 on the piston rod side is clearly visible. As in Figure 4a shown schematically, the second connection 34 includes a second through-opening 35. This second through-opening 35 preferably extends from a lateral surface 62 of the cylinder base 12 to the intermediate space 40 formed by the first and second cylinder tubes 14, 16. The second through-opening extends, for example 35 from the gap 40 obliquely upwards. The second terminal 34 is used to connect a second connecting line 54. This second connecting line 54 is in Figure 4a not shown. According to Figure 1a to 4a are the second connection 34, the gap 40, the recess 42 of the rod bushing 22 and the pressure chamber 38 on the piston rod side are connected to one another.

Figure 4b shows a schematic representation of a piston-side end of the in Figure 1a shown double-acting hydraulic cylinder 10. In particular, in Figure 4b the first and second connection 32, 34 clearly visible. As in Figure 4b shown, the first port 32 extending through the cylinder base 12 is arranged, for example, in a central area of the double-acting hydraulic cylinder 10, while the second port 34 extending through the cylinder base 12 is arranged, for example, in a lateral area of the double-acting hydraulic cylinder 10. According to Figure 4b Both the first connection 32 and the second connection 34 can be provided on the piston-side end of the double-acting hydraulic cylinder 10 .

figure 5 shows an exemplary schematic diagram of a double-acting hydraulic cylinder 10, which is not covered by the claims. In the embodiment of figure 5 includes the double-acting hydraulic cylinder 10 only a single cylinder tube 14. In particular, the double-acting hydraulic cylinder 10 according to the embodiment of FIG figure 5 not the second cylinder tube 16 of the double-acting hydraulic cylinder 10 according to the embodiment of Figure 1a . Thus, the embodiment of figure 5 to another aspect of the present invention. the inside figure 5 The double-acting hydraulic cylinder 10 shown comprises the piston 26 guided in the cylinder tube 14 and separating the pressure chamber 36 on the piston side from the pressure chamber 38 on the piston rod side. The pressure chamber 36 , 38 on the piston side and the piston rod side are formed by the cylinder tube 14 . Furthermore, a rod bushing 22 on the piston rod side is provided, which receives the piston rod 24 and guides it linearly.

At the in figure 5 shown embodiment includes the double-acting hydraulic cylinder 10, the first and second port 32, 34. According to figure 5 the first connection 32 is used to apply a hydraulic fluid to the pressure chamber 36 on the piston side, while the second connection 34 is used to apply the hydraulic fluid to the pressure chamber 38 on the piston rod side. Further includes according to figure 5 the first port 32 includes a first through hole 33 while the second port 34 includes a second through hole 35 . These first and second through-openings 33, 35 preferably extend completely through the piston rod 24. The first and second through-openings 33, 35 extend essentially parallel to the longitudinal axis 30 of the double-acting hydraulic cylinder 10. According to FIG figure 5 extends the first Through opening 33 from an end of the piston rod 24 facing away from the piston 26 through the piston rod 24 to an end of the piston rod 24 facing the piston 26. Furthermore, according to FIG figure 5 the second passage opening 35 from the end of the piston rod 24 facing away from the piston 26 through the piston rod 24 to the end of the piston rod 24 facing the piston 26. As in FIG figure 5 shown, the first through opening 33 extends further from the end of the piston rod 24 facing the piston 26 parallel to the longitudinal axis 30 of the double-acting hydraulic cylinder 10 and completely through the piston 26 to the pressure chamber 36 on the piston side figure 5 shown that the second passage opening 35 continues to be angled from the end of the piston rod 24 facing the piston 26 and partially extends through the piston 26 to the pressure chamber 38 on the piston rod side. Thus, according to the embodiment of figure 5 the pressure chambers 36 , 38 on the piston side and the piston rod side are pressurized with the hydraulic fluid via the first or second connection 32 , 34 provided in the piston rod 24 .

Look at the following Figures 6a, 6b , 7a and 7b some advantages of the present invention over the known prior art are explained.

Figure 6a shows a schematic representation of a double-acting hydraulic cylinder 10 with a first connection 32 and a second connection 34 according to an exemplary embodiment. As in Figure 6a shown, the first and second connection 32, 34 are arranged on the cylinder base 12 of the double-acting hydraulic cylinder 10. Furthermore, in Figure 6a shown that the first and second port 32, 34 are connected to a hydraulic unit 50. First port 32 is preferably connected to an A port of hydraulic unit 50 via a first connecting line 52 , while second port 34 is connected to a B port of hydraulic unit 50 via a second connecting line 54 . The A port of the hydraulic unit 50 is used to supply the first port 32 with a hydraulic fluid, while the B port of the hydraulic unit 50 is used to supply the second port 34 with the hydraulic fluid.

At the in Figure 6a In the exemplary embodiment shown, the end of the double-acting hydraulic cylinder 10 on the piston rod side is connected to a unit 56 on the piston rod side. The unit 56 on the piston rod side can be displaced in the first or second direction of piston movement P1, P2 with the aid of the double-acting hydraulic cylinder 10. In Figure 6a the installation space 58 for the double-acting hydraulic cylinder 10 is shown in particular. The installation space 58 is in Figure 6a shown schematically by dashed lines. At the in Figure 6a In the exemplary embodiment shown, the installation space 58 is essentially defined by the outer surface 44 of the second cylinder tube 16 . The installation space 58 thus essentially corresponds to that in figure 2 shown dimension D1. In particular, the installation space 58 for the double-acting hydraulic cylinder 10 according to the embodiment of Figure 6a relatively small compared to the prior art.

Figure 6b shows a schematic representation of a double-acting hydraulic cylinder 100 with a connection 114 on the B-side of the double-acting hydraulic cylinder 100. In Figure 6b In particular, the connection 114 arranged on the piston rod-side end of the double-acting hydraulic cylinder 100 is shown. The other connection 112, which is arranged on the piston-side end of the double-acting hydraulic cylinder 100, is in Figure 6b not shown. These connections 112, 114 are connected to the A connection or B connection of a hydraulic unit 50 via two connecting lines 52, 54. The installation space 128 for the double-acting hydraulic cylinder 100 according to Figure 6b is shown schematically by dashed lines. In particular, the installation space 128 is essentially given by the lateral expansion of the surface of the cylinder tube 102 and the exposed banjo bolt 122 . So the in Figure 6b The installation space 128 shown according to the prior art is relatively large compared to the installation space 58 according to the embodiment of FIG Figure 6a .

Figure 7a shows a schematic longitudinal sectional view of a double-acting hydraulic cylinder 10 according to an embodiment. In particular, in Figure 7a the installation space 58 is shown. In the embodiment of Figure 7a the second connection 34 comprises an exposed hollow screw 60. The exposed hollow screw 60 preferably extends through an annular eyelet 64 into the second through opening 35. As in FIG Figure 7a As shown, the exposed banjo bolt 60 is located on the cylinder base 12 . In particular, the in Figure 7a shown, exposed hollow screw 60 for connecting the second connecting line 54.

Furthermore, in Figure 7a dimensions D1 to D4 are shown. Dimension D1 corresponds to the outside diameter of the second cylinder tube 16, dimension D2 corresponds to the inside diameter of the first cylinder tube 14, dimension D3 corresponds to the wall thickness of the first and second cylinder tubes 14, 16, and dimension D4 corresponds to the wall thickness of the first cylinder tube 14. Preferably dimension D1 is 50 mm, dimension D2 is 35 mm, dimension D3 is 7.5 mm and dimension D4 is 3.5 mm.

Figure 7b shows a schematic longitudinal sectional view of a double-acting hydraulic cylinder 100 according to the prior art. In Figure 7b the installation space 128 is clearly visible. Furthermore, in Figure 7b dimensions L1 to L3 are shown. The dimension L2 corresponds to the inside diameter of the cylinder tube 102, while the dimension L3 corresponds to the wall thickness of the cylinder tube 102. Preferably, dimension L1 is 20mm, dimension L2 is 35mm and dimension L3 is 3.5mm.

Referring to Figure 7a For example, at an operating pressure of 70 to 300 bar with a piston diameter or inner diameter D2 of the first cylinder tube 14 of 35 mm according to the present invention, the sketched, cylindrical installation space 58 can be maintained by skillful placement of the second connection 34 . The determining outer diameter D1 of the lateral surface 44 is only 50 mm. This outside diameter D1 of the lateral surface 44 is at most 7.5 mm larger than the piston diameter or inside diameter D2 of the first cylinder tube 14. With other piston diameters and comparable pressure, the dimension 7.5 remains constant.

In contrast, the in Figure 7b In the prior art shown, the connection 114 or the exposed banjo bolt 122 is typically 23.5 mm beyond the piston diameter or inner diameter L2 of the cylinder tube 102 . Because of the drawn thread depth for a typically used hollow screw M8x1, the known solution cannot be optimized like the solution according to the invention.

Embodiments of the present invention provide a space-saving, safe supply of energy within a double-acting hydraulic cylinder 10 and mounting the A and B ports 32, 34 on the cylinder housing 12 close to each other.

In particular, the present invention has the following advantages. The installation space 58 can be made significantly smaller in diameter due to the solution according to the invention. This saves installation space in particular. The solution according to the invention relates primarily to double-acting hydraulic cylinders. The double-acting hydraulic cylinder 10 according to the present invention can be used in particular with operating tables. If the supply unit/control unit 50 of the cylinder 10 is preferably attached to the kinematics of the cylinder base 12 when the cylinder 10 travels long distances, the connecting lines 52, 54 to the two connections 32, 34 do not experience any relative movement. If the power unit/controller 50 were to be attached to the rod end unit 56, the hoses would have a large change in length experienced when extending the cylinder 10. The solution according to the invention makes it possible to attach the B connection 34 to the cylinder base 12 as well. This is not possible with the prior art. In this case, the connection 114 has to be attached unfavorably to the rod end via the ring eye 120. According to exemplary embodiments, the exposed banjo bolt 122 with the threaded bushing 120 on the lateral surface of the cylinder tube 102 is omitted. In particular, damage to the exposed banjo bolt 122 due to the movements of the cylinder 10 or assembly on the bore 128 can be ruled out, since the banjo bolt 60 in the solution according to the invention is attached to the cylinder base 12 outside of the installation space 58 . Furthermore, the B-side can be supplied with the hydraulic fluid via the double-pipe solution according to the invention instead of via the lines laid outside according to the prior art. The short, flexible lines according to exemplary embodiments are also considerably less susceptible to damage.

In contrast to known applications with connections 212, 214 according to Figure 8b According to exemplary embodiments, a correspondingly large amount of space can be left free for the banjo bolts.

For applications with little installation space, the supply of the hydraulic fluid, such as an oil supply, can also be realized via the piston rod 24, as is the case in the exemplary embodiment of FIG figure 5 is shown. For this purpose, for example, two bores 33, 35 can be made in the piston rod 24 or several tubes can be slid into one another in order to obtain two separate, oil-carrying spaces. The A port 32 and the B port 34 are located at the outer end of the piston rod 24 . This in figure 5 shown embodiment has compared to in Figure 1a shown embodiment has the disadvantage that the cross section of the piston rod 24 is weakened by the oil bores 33, 35. Furthermore, a long cylinder rod 24, such as. B. with a ratio of length to diameter of the piston rod greater than 30, more susceptible to buckling due to the weakening. In addition, arising from the construction after figure 5 compared to the structure after Figure 1a relatively high costs due to the holes 33, 35.

Instead of using Figure 1a described differential cylinder 10, the double-acting hydraulic cylinder can also be designed as a synchronous cylinder or tandem cylinder.

Reference List

10

double-acting hydraulic cylinder

12

cylinder bottom

14, 16

cylinder barrel

18a to 18c

sealing element

20a, 20b

holding element

22

Closure with piston rod passage

24

piston rod

26

Pistons

28a, 28b

screw connection

30

longitudinal axis

32, 34

connection

33.35

passage opening

36, 38

pressure room

40

space

41

section

42

recess

44

surface

46a to 46e

screw

48a to 48c

cutting line

50

hydraulic unit

52, 54

connection line

56

rod side unit

58

installation space

60

banjo bolt

62

surface

64

ring eye

100, 200

State-of-the-art double-acting hydraulic cylinder

100 to 128, 212, 214

Components of the well-known, double-acting hydraulic cylinder

P1, P2

piston movement direction

D1 to D4, L1 to L3

dimension

Claims (11)

1. A double-acting hydraulic cylinder (10),

   with a first cylinder housing (14) and a piston (26) guided in the first cylinder housing (14), wherein a first pressure chamber (36) and a second pressure chamber (38) are provided in the first cylinder housing (14), which are separated from each other by the piston (26), with a first connection (32) at least for delivering a hydraulic fluid to the first pressure chamber (36) and a second connection (34) at least for delivering the hydraulic fluid to the second pressure chamber (38), and with a second cylinder housing (16) which surrounds the first cylinder housing (14) at least in one section (41), wherein the first connection (32) and the second connection (34) are arranged at an end of the double-acting hydraulic cylinder (10) facing away from the second pressure chamber (38),

   wherein the second pressure chamber (38) is able to be supplied with the hydraulic fluid via the section (41) in which the second cylinder housing (16) surrounds the first cylinder housing (14),

   wherein the end of the double-acting hydraulic cylinder (10) facing away from the second pressure chamber (38) comprises a cylinder base (12),

   wherein the first connection (32) and the second connection (34) are arranged on the cylinder base (12), wherein the first connection (32) comprises a first through opening (33) and the first through opening (33) extends from a lateral surface (62) of the cylinder base (12) to the first pressure chamber (36),

   characterized in that

   the cylinder base (12) encloses an end of the first cylinder housing (14) facing away from the second pressure chamber (38) and an end of the second cylinder housing (16) facing away from the second pressure chamber (38), and

   the first through opening (33) extends from and essentially perpendicular to the lateral surface (62) of the cylinder base to the first pressure chamber (36).
2. The double-acting hydraulic cylinder (10) according to claim 1, characterized in that the section (41) extends along the longitudinal axis (30) of the hydraulic cylinder (10).
3. The double-acting hydraulic cylinder (10) according to claim 1 or 2, characterized in that the first pressure chamber (36) is a piston-side pressure chamber, and in that the second pressure chamber (38) is a piston-rod-side pressure chamber.
4. The double-acting hydraulic cylinder (10) according to any one of the preceding claims, characterized in that a first sealing element (18a) is arranged between the end of the first cylinder housing (14) facing away from the second pressure chamber (38) and the cylinder base (12), and in that a second sealing element (18b) is arranged between the end of the second cylinder housing (16) facing away from the second pressure chamber (38) and the cylinder base (12).
5. The double-acting hydraulic cylinder (10) according to any one of the preceding claims, characterized in that the second connection (34) comprises a second through opening (35), and in that the second through opening (35) extends from a lateral surface (62) of the cylinder base (12) to the section (41) in which the second cylinder housing (16) surrounds the first cylinder housing (14).
6. The double-acting hydraulic cylinder (10) according to any one of claims 1 to 5, characterized in that the first cylinder housing (14) and the second cylinder housing (16) are arranged such that a gap (40) is formed between the first cylinder housing (14) and the second cylinder housing (16), wherein the gap (40) extends from the end of the double-acting hydraulic cylinder (10) facing away from the second pressure chamber (38) to an end of the double-acting hydraulic cylinder (10) facing away from the first pressure chamber (36).
7. The double-acting hydraulic cylinder (10) according to any one of claims 1 to 6, characterized in that the double-acting hydraulic cylinder (10) comprises a rod bushing (22), wherein the rod bushing (22) is arranged at an end of the double-acting hydraulic cylinder (10) facing away from the first pressure chamber (36), and wherein the rod bushing (22) is designed such that a piston rod (24) connected to the piston (26) is moved in a first piston movement direction (P1) when the hydraulic fluid is supplied to the first pressure chamber (36) and is moved in a second piston movement direction (P2) opposite to the first piston movement direction (P1) when the hydraulic fluid is supplied to the second pressure chamber (38).
8. The double-acting hydraulic cylinder (10) according to claim 7, characterized in that the rod bushing (22) comprises a recess (42), and in that the second pressure chamber (38) is able to be supplied with the hydraulic fluid via the section (41) in which the second cylinder housing (16) surrounds the first cylinder housing (14) and via the recess (42) of the rod bushing (22).
9. The double-acting hydraulic cylinder (10) according to any one of claims 1 to 8, characterized in that the first cylinder housing (14) comprises a first cylinder tube, and in that the second cylinder housing (16) comprises a second cylinder tube.
10. The double-acting hydraulic cylinder (10) according to claim 9, characterized in that the double-acting hydraulic cylinder (10) comprises at least one first holding element (20a) for holding the second cylinder housing (16), wherein the at least one first holding element (20a) is arranged at least partway around the second cylinder housing (16) on an outer surface (44) of the second cylinder housing (16).
11. The double-acting hydraulic cylinder (10) according to any one of claims 1 to 10, characterized in that the first connection (32) is designed such that it is connectable to a first connection line (52) at least for delivering the hydraulic fluid, and in that the second connection (34) is designed such that it is connectable to a second connection line (54) at least for delivering hydraulic fluid.

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