Hydraulic cylinder, method for its manufacture and drill hammer equipped therewith

Abstract

Hydraulic cylinder (1) with a housing (10) having a cylinder bore (15) in which a piston (2) is slidably mounted, wherein a first fluid supply (151) for supplying a drive fluid into the cylinder bore (15) is arranged at a first end (101) of the housing (10) and a second fluid supply (152) for supplying the drive fluid into the cylinder bore (15) is arranged at a second end (102) of the housing (10), wherein a flow channel (3) extends between the second fluid supply (152) and the first end (101) of the housing (10), characterized in that the housing (10) has a housing core (18) and a housing shell (19), wherein a shrink connection exists between the housing core (18) and the housing shell (19) and at least one longitudinal section of the flow channel (3) is formed by a groove (35) in the housing core (18). is.

Description

[0001] The invention relates to a hydraulic cylinder with a housing containing a cylinder bore in which a piston is slidably mounted, wherein a first fluid supply for supplying a drive fluid into the cylinder bore is arranged at a first end of the housing and a second fluid supply for supplying the drive fluid into the cylinder bore is arranged at a second end of the housing, wherein a flow channel extends between the second fluid supply and the first end of the housing. The invention further relates to a method for manufacturing such a hydraulic cylinder, as well as an actuator and a drill hammer with such a hydraulic cylinder.

[0002] Hydraulic cylinders are a well-known design in which a piston slides within a cylinder bore of a housing. The piston can be alternately actuated from one side or the other with a drive fluid, causing it to move within the cylinder bore. This movement can be transmitted to other components via a pushrod. Hydraulic cylinders of this type are used, for example, in construction and machine tools. Furthermore, such hydraulic cylinders can be used as hammer mechanisms in drilling and chiseling equipment.

[0003] These well-known hydraulic cylinders have the disadvantage that the fluid inlets are usually located at both ends of the cylinder housing to allow the supply of drive fluid from both sides of the piston. However, it is often advantageous to supply the drive fluid from only one side of the hydraulic cylinder. In this case, a flow channel is located outside the housing, extending from the second fluid inlet at the other end of the housing to the first end. Such external fluid channels can, for example, be designed as pipes. These are therefore exposed and susceptible to potential damage. In the case of drilling rigs, which are fully lowered into a borehole as drilling progresses, external lines are generally undesirable due to the increased cross-sectional area.

[0004] To solve this problem, it is known in practice to drill holes in the housing wall of the hydraulic cylinder so that the flow channel runs inside the housing. However, producing relatively thin and long holes is complex. Often, these cannot be machined by subtraction but must be created, for example, by electrical discharge machining (EDM), which further increases the machining time and thus the manufacturing costs.

[0005] US 2,761,425 A and DE 29 394 22 A1 disclose a hydraulic cylinder with a housing containing a cylinder bore in which a piston is slidably mounted. A first fluid supply for feeding a drive fluid into the cylinder bore is arranged at a first end of the housing, and a second fluid supply for feeding the drive fluid into the cylinder bore is arranged at a second end of the housing, with a flow channel extending between the second fluid supply and the first end of the housing. DE 93 03 048 U1 discloses a hydraulic cylinder with a housing containing a cylinder bore in which a piston is slidably mounted.At a first end of the housing, a first fluid supply is arranged for supplying a drive fluid into the cylinder bore, and at a second end of the housing, a second fluid supply is arranged for supplying the drive fluid into the cylinder bore, wherein a flow channel extends between the second fluid supply and the first end of the housing, wherein a closure element is arranged at the first end of the housing, which has a damping chamber on an inner side facing the cylinder bore.

[0006] Based on the prior art, the invention is therefore based on the objective of providing a hydraulic cylinder which, on the one hand, has an internal flow channel and, on the other hand, can be manufactured with low manufacturing effort.

[0007] The problem is solved according to the invention by a hydraulic cylinder according to claim 1, a method according to claim 10, and an actuator or a hammer drill according to claim 17. Advantageous embodiments of the invention are found in the dependent claims.

[0008] According to one aspect of the invention, a hydraulic cylinder with a housing containing a cylinder bore is proposed. The housing can have a polygonal or round outer cross-section. The cylinder bore contained therein can also be polygonal or round. For reasons of simplified manufacturing, both the outer cross-section and the cylinder bore are often round. The housing can be made of a metal or an alloy. In some embodiments of the invention, the housing can contain or consist of a plastic, which may also include optional fiber reinforcement. The cylinder bore can be formed during the initial shaping of the housing. In other embodiments of the invention, the cylinder bore can be machined, for example, by turning, drilling, honing, or other methods known per se.

[0009] In some embodiments of the invention, the housing can have a length of approximately 15 mm to approximately 100 mm, or approximately 100 mm to approximately 800 mm, or approximately 500 mm to approximately 1500 mm. The diameter of the housing can, in some embodiments of the invention, be between approximately 20 mm and approximately 200 mm, or approximately 20 mm to approximately 60 mm, or approximately 50 mm to approximately 150 mm. The wall thickness of the housing, which results from the difference between the outer diameter and the diameter of the cylinder bore, can be between approximately 5 mm and approximately 20 mm, or between approximately 10 mm and approximately 80 mm.

[0010] The housing has at least one fluid inlet at its first end, through which a drive fluid can be introduced into the cylinder bore. Similarly, at least one second fluid inlet is located at the second end of the housing for supplying the drive fluid into the cylinder bore. In some embodiments of the invention, the housing can be symmetrical, so that the first and second ends of the housing are indistinguishable.

[0011] In the cylinder bore of the hydraulic cylinder housing, at least one piston is located, which is slidably mounted within the cylinder bore. In some embodiments of the invention, the piston can form a fit in the cylinder bore, so that it slides within the cylinder bore with a seal. In some embodiments of the invention, at least one seal, for example an O-ring seal and / or a lip seal, can be arranged between the piston wall and the cylinder bore. In other embodiments of the invention, a clearance fit can exist between the piston and the cylinder bore, which has a gap between the piston and the cylinder. The flow resistance through this gap can, in some embodiments, be sufficient to move the piston within the cylinder bore with the desired force and / or speed.

[0012] During operation of the hydraulic cylinder, a drive fluid is supplied through the first or second fluid inlet, which moves the piston in the opposite direction and expels the drive fluid located in the other chamber of the cylinder bore. By supplying the drive fluid, the hydraulic cylinder can thus be moved by a specific distance in a manner known per se, for example, to move a mechanical component of a construction or machine tool or a part of a vehicle or aircraft. In some embodiments of the invention, the hydraulic cylinder can be actuated in rapid succession to generate an oscillating force with the oscillating piston. Such a hydraulic cylinder can be part of a percussion mechanism of a drill or chisel or a demolition hammer, wherein the hydraulic cylinder with the oscillating piston exerts a percussive force on a drill or chisel tool.In other embodiments of the invention, the hydraulic cylinder can be used to control a harvesting vibrator for fruit trees or a vibrating compactor.

[0013] In some embodiments of the invention, the drive fluid can be gaseous or liquid. For example, the drive fluid can be compressed air, water, or hydraulic oil. The drive fluid is supplied in a manner known per se via at least one pump and at least one switching element, which controls the supply of the drive fluid either to the first fluid supply or to the second fluid supply.

[0014] According to one aspect of the invention, it is proposed that the housing be constructed in multiple parts, comprising a housing core and a housing shell surrounding the housing core, with a shrink-fit connection between the housing core and the housing shell. In this case, the housing core can be manufactured simply as a turned and / or milled part and / or as a casting and / or as a forging. In some embodiments of the invention, the housing shell can also be machined. In other embodiments of the invention, the housing shell can be a drawn precision tube exhibiting low dimensional and geometric tolerances. For assembly, the housing core can be cooled and / or the housing shell heated. If a temperature difference exists, the two components can be easily joined by inserting them into one another. After temperature equalization, the housing shell and the housing core form a permanent press fit.This design offers the advantage that at least one longitudinal section of the flow channel can be formed by a groove in the housing core. Creating a groove by milling, broaching, grinding, or similar machining processes, or even during the initial forming of the housing core in a casting or forging process, is considerably simpler than creating a high aspect ratio bore according to the prior art. After the shrink-fit connection between the housing core and the housing shell is established, the housing shell closes the open groove, thus forming a closed flow channel. In this way, at least one or more flow channels can be easily integrated into the hydraulic cylinder, which connects the second fluid supply from the second end of the housing to the first end of the housing.The hydraulic lines can therefore be connected at one end of the housing without having to route exposed lines on the outside of the hydraulic cylinder housing.

[0015] In some embodiments of the invention, the outer diameter of the housing core can have an interference of approximately 0.02% to approximately 0.2% relative to the inner diameter of the housing shell. In other embodiments of the invention, the outer diameter of the housing core can have an interference of approximately 0.08% to approximately 0.12% relative to the inner diameter of the housing shell. In still other embodiments of the invention, the outer diameter of the housing core can have an interference of approximately 0.09% to approximately 0.11% relative to the inner diameter of the housing shell. In some embodiments of the invention, an interference fit of class u6 or better according to ISO 286 can be formed between the housing core and the housing shell. These interference fits can be produced with comparatively low manufacturing effort and, after shrink-fitting the housing shell, enable a fluid-tight and mechanically robust connection between the housing core and the housing shell.

[0016] In some embodiments of the invention, the housing shell can be made in two parts, with the two parts of the housing shell being welded together. This embodiment facilitates the assembly of the housing shell, particularly in the case of very long housings, by sliding a first part of the housing shell onto the housing core from the first side and a second part of the housing shell onto the housing core from the second side. The joint of the housing shell resulting from the butt joint can then be welded to ensure fluid tightness at this point as well.

[0017] In some embodiments of the invention, an annular groove can be provided at the first end and / or the second end of the housing core, which communicates with the groove forming the flow channel. Such an annular groove facilitates the fluid supply to the flow channel. The annular groove can also be easily machined, for example by external turning, of the housing core and completed to form a closed flow channel during the subsequent shrink-fitting of the housing shell. In particular, if the closure elements attached to both sides of the housing are designed as screw caps, the annular groove can easily ensure that the line connection of the closure element communicates with the grooves forming the flow channels, without the exact angular position of the closure element relative to the housing being critical.

[0018] In some embodiments of the invention, a closure element may be provided at the first end of the housing, which has a line connection that opens into the annular groove. The closure element may be connected to the housing by pressing, screwing, gluing, or welding. In particular, a screw connection allows for easy maintenance of the hydraulic cylinder, even in the field.

[0019] According to one aspect of the invention, it is proposed that a closure element be arranged at one end of the housing, which has a damping chamber on its inner surface facing the cylinder bore. Such a damping chamber can prevent or dampen the piston's impact with the closure element, thus preventing components from being subjected to unnecessary stress from impacts or vibrations. In some embodiments of the invention, such a damping chamber can be arranged on both sides of the hydraulic cylinder, for example, when used as a hydraulic actuator. In other embodiments of the invention, the damping chamber can be arranged on only one side of the hydraulic cylinder. This embodiment is suitable, for example, as an impact mechanism for a drilling or chiseling tool, where impulse transmission in one direction is desired, but should be prevented or dampened in the other direction.The use of a closure element which has a damping chamber on its inner side facing the cylinder bore is possible both in known one-piece housings and in the multi-piece housings described above according to one aspect of the invention, which have a housing core and at least one housing shell.

[0020] In some embodiments of the invention, the piston has a damper plunger on its side facing the damping chamber, which is configured to engage in the damping chamber. The damper plunger is undersized relative to the damping chamber, allowing it to engage and displace hydraulic fluid from the chamber. This dissipates energy and reduces the piston's impact velocity on the sealing element.

[0021] In some embodiments of the invention, the damping chamber and damping piston can be complementary in shape and, for example, be polygonal, round, or oval. In other embodiments of the invention, a polygonal damping piston can engage in a round damping chamber, or vice versa. In this case, it can be advantageous for the round component to form the incircle or circumcircle of the polygonal component. The fluid channels thus formed between the damping piston and the damping chamber can be selected in size to achieve the desired flow resistance and, consequently, the desired damping behavior.

[0022] In some embodiments of the invention, at least one vortex chamber can be provided in the side wall of the damping chamber and / or in the side wall of the damper piston. In some embodiments of the invention, the vortex chamber can have the form of a circumferential groove. In other embodiments of the invention, the vortex chamber can be provided in the form of a bore or recess. The number of vortex chambers can be between one and about ten or between one and five. The vortex chambers have the effect of making the flow of the fluid ejected from the damping chamber turbulent, and in this way, additional energy can be dissipated.

[0023] In some embodiments of the invention, the hydraulic cylinder can have a passage at the second end of the housing for a push rod, which is connected to the piston. In this way, the force exerted on the piston can be transmitted to other components, for example, the bucket or stick of an excavator, or to a chisel or a drilling tool.

[0024] In some embodiments of the invention, the cylinder bore at the second end of the housing can be closed. In this case, the piston can strike the closing element at the second end of the housing and thereby exert an impulse on the hydraulic cylinder, which can be transmitted to a drilling or chiseling tool that is in contact with the hydraulic cylinder. This embodiment has the advantage that additional sealing elements between a push rod and the closing element of the cylinder bore can be omitted. This can increase operational reliability.

[0025] In some embodiments of the invention, during the manufacture of the proposed hydraulic cylinder, the temperature difference ΔT between the housing shell and the housing core can be greater than or equal to ΔT=ΔDD⋅α Let ΔD be the oversize of the housing core relative to the housing shell, D the inner diameter of the housing shell, and a the coefficient of thermal expansion of the housing shell. In this way, the minimum required temperature difference for joining the housing shell and housing core can be easily determined, thus avoiding unnecessarily large heating and the associated energy consumption.

[0026] In some embodiments of the invention, the coefficient of thermal expansion α of the housing shell can be between approximately 7 · 10 -6 K -1 and about 15 · 10 -6 K -1 In other embodiments of the invention, the coefficient of thermal expansion α of the housing shell can be between approximately 10 · 10 -6 K -1 and about 12 · 10 -6 K -1 This results in a reliable shrink connection with low energy consumption.

[0027] The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention. This will show Fig. 1 a drilling tool with a known hydraulic cylinder. Fig. Figure 2 shows a hydraulic cylinder according to one aspect of the invention in cross-section. Fig. Figure 3 shows a hydraulic cylinder according to a first embodiment in longitudinal section. Fig. Figure 4 shows a hydraulic cylinder according to a second embodiment in longitudinal section. Fig. Figure 5 shows a hydraulic cylinder according to a third embodiment in perspective view. Fig. Figure 6 shows an optional filter element.

[0028] Fig. Figure 1 shows a hydraulic cylinder 1 with a housing 10 containing a cylinder bore 15. The housing can be made of a metal or alloy, for example. A piston 2 is slidably mounted in the cylinder bore 15. Furthermore, the housing has a first fluid inlet 151 at its first end 101. A second fluid inlet 152 is located at the opposite second end 102. The housing 10, the cylinder bore 15, and the piston 2 are usually designed with a round cross-section. However, other designs are also conceivable, in particular polygonal or elliptical ones.

[0029] A switching element 5 supplies a drive fluid either via a first line connection 31 to the first fluid supply 151. Alternatively, a drive fluid can be supplied via the switching element 5 via a second line connection 32 and a flow channel 3 to the second fluid supply 152. The piston 2 moves accordingly to the second end 102 or to the first end 101. As shown in the diagram... Fig. As can be seen in Figure 1, the flow channel 3 is designed as an external pipe on the housing 10 of the hydraulic cylinder 1. This increases the outer cross-section of the housing 10 and makes the flow channel 3 susceptible to damage.

[0030] The movement of the piston 2 is transmitted via a push rod 29 to a subsequent component. In the illustrated embodiment, this is a drill bit 6, which penetrates a rock formation 65 by repeatedly applying force peaks to the drill bit 6, causing the rock to fracture.

[0031] The drive fluid can be compressed air, water, or hydraulic oil. The required operating pressure is generated by means of a... Fig. 1 pump not shown, provided in a manner known per se.

[0032] Based on the Fig. 2 and Fig. Section 3 explains in more detail a first embodiment of the present invention. It shows Fig. 2 the cross-section through the housing 10 of a hydraulic cylinder 1. Fig. Figure 3 shows a longitudinal section in the area of ​​the first end 101.

[0033] As can be seen from the figures, the housing 10 of the hydraulic cylinder 1 consists of a housing core 18 and a housing shell 19. It is also evident that the flow channels 3 are arranged inside the housing 10. In this way, the flow channels 3 are protected against mechanical damage. Furthermore, the flow channels 3 do not increase the outer cross-section, so that the hydraulic cylinder, for example as part of a drilling rig, can be completely enclosed in the borehole.

[0034] In the illustrated embodiment, six flow channels 3 are shown. In other embodiments of the invention, the number may be larger or smaller. The invention does not teach the use of a specific number of flow channels as a solution principle. As will be shown below with reference to Fig. As explained in more detail in section 4, in some embodiments of the invention the flow channels 3 can also run on the outside of the housing 10 in a manner known per se or be introduced into the housing wall in another way, in particular as a bore.

[0035] How Fig. As further shown in Figure 2, the flow channels 3 consist of grooves 35, which can be produced in the housing core 18, for example, by milling, filing, broaching, or other known machining processes. In some embodiments of the invention, the grooves 35 can also be formed during the initial shaping of the housing core 18 in a casting or forging process. Particularly in the case of very long hydraulic cylinders, the open grooves 35 can thus be manufactured considerably more easily than closed bores with a small diameter and a large length.

[0036] The housing core 18 is subsequently provided with a housing shell 19. The housing shell 19 can also be machined and, for example, produced by turning. In some embodiments of the invention, the housing shell 19 can be designed as a drawn precision tube, so that no further machining steps are required for the production of the housing shell 19 other than cutting it to length.

[0037] To manufacture the housing 10 from the housing core 18 and the housing shell 19, it is proposed to cool the housing core and / or heat the housing shell 19. The required temperature difference can be, for example, more than 150 K, more than 200 K, more than 300 K, or more than 400 K. The temperature difference depends on the coefficient of thermal expansion α of the materials involved, the outer diameter, and the manufacturing tolerances or the interference fit between the housing core 18 and the housing shell 19.

[0038] After creating a temperature difference that more than compensates for the excess dimensions of the two components, the housing core 18 and the housing shell 19 can be easily fitted together. After cooling or temperature equalization, a shrink-fit connection forms between the components, which seals the open grooves 35 to the environment and thus creates closed flow channels 3.

[0039] The in Fig. Figure 3, longitudinal section according to a first embodiment of the invention, shows a closure element 4 which is provided with two line connections 31 and 32. The line connection 31 leads via a flow channel to a fluid supply 151, which introduces the drive fluid into the cylinder bore 15 on the first side 101.

[0040] The second line connection 32 deflects the flow introduced there at approximately a right angle. From there, the drive fluid 55 enters an annular groove 185, which is formed in the housing core 18. The annular groove 185 can also be easily manufactured, for example by machining, and is sealed to the environment by shrink-fitting the housing shell 19. The annular groove 185 is connected to the groove(s) 35 forming the flow channel 3, so that the drive fluid 55 can flow from the annular groove 185 via the flow channel 3 to the second fluid supply 152 at the second end 102 of the housing 10.

[0041] How Fig. As further shown in Figure 3, the sealing element 4 is screwed into the housing 10 by means of a thread 48. To ensure a tight seal and prevent leakage of the drive fluid, one or more seals 45 may be provided. In the illustrated embodiment, the seals 45 are designed as O-ring seals, which are arranged on both sides of the annular groove 185. In other embodiments, other seals may be used, for example, a lip seal or a metal seal.

[0042] At the second end 102 (not shown), a simple, fully enclosed closure element can be arranged. During operation of the hydraulic cylinder, the piston 2 strikes this closure element, thereby transferring its momentum to a drilling tool in contact with it. Such a hydraulic cylinder can be easily assembled from four parts: a housing 10, a piston 2, and the first and second closure elements. This allows for simple assembly and maintenance, even in the field.

[0043] Based on the Fig. Figure 4 shows an alternative embodiment of the locking element 4. This illustrates Fig. 4 also another section through the housing 10, as shown by the Fig. 2 explained. While in Fig. 3 the flow channels 3 are shown in section, these are in the section according to Fig. 4 not discernible. It is known to those skilled in the art that these details apply regardless of the use of the depicted locking element 4.

[0044] In some embodiments, the Fig. 4 The alternative embodiment of the closure element 4 described above can also be used with a conventional, one-piece housing 10, which either contains flow channels as bores in the housing wall or in which the flow channel 3 is as in Fig. Figure 1 shows the outer surface of the housing 10. In this case, the invention relates to a hydraulic cylinder 1 with a housing 10 having a cylinder bore 15 in which a piston 2 is slidably mounted, wherein a first fluid supply 151 for supplying a drive fluid into the cylinder bore 15 is arranged at a first end 101 of the housing 10 and a second fluid supply 152 for supplying the drive fluid into the cylinder bore 15 is arranged at a second end 102 of the housing 10, wherein a flow channel 3 extends between the second fluid supply 152 and the first end 101 of the housing 10, wherein a closure element 4 is arranged at the first end 101 of the housing 10, which has a damping chamber 44 on an inner surface facing the cylinder bore 15.

[0045] The closure element 4 according to the second embodiment also has two line connections 31 and 32. The channel connecting the line connection 32 to the annular groove 185 lies outside the plane of the section and is in Fig. 4 not shown.

[0046] The difference between the closure element 4 according to the second embodiment and the first embodiment primarily concerns the damping chamber 44, which is arranged on the inner side of the closure element 4 facing the cylinder bore. The damping chamber 44 can have a polygonal or round cross-section. Optional vortex chambers 445 are arranged on its side wall 441. In the illustrated embodiment, three vortex chambers are shown, each having the form of a circumferential groove.

[0047] Furthermore, the piston 2 has a damper plunger 24 at its end facing the damping chamber 44, which is designed to engage in the damping chamber 44. The damper plunger 24 can be shaped complementarily to the cross-section of the damping chamber 44. Alternatively, the damper plunger 24 is smaller and can, for example, have a round cross-section, while the damping chamber 44 is polygonal, or vice versa.

[0048] During operation of the device, the hydraulic fluid is trapped or dammed up in the damping chamber 44 during the upward movement of the piston 2, thus decelerating the piston 2 and reducing the peak force occurring when it impacts the sealing element 4. As soon as the damping plunger 24 engages in the damping chamber 44, the drive fluid is diverted at the gap between the two components, creating turbulence in the vortex chambers 445, which further dissipates energy. The sealing element 4 according to the second embodiment can be used advantageously, particularly in impact or hammer mechanisms for drilling tools, to exert a large peak force on the drilling tool in the feed direction and to reduce the stress on the device during the reverse movement.

[0049] Fig. Figure 5 shows a housing core 18 according to a third embodiment of the invention in a perspective view. The grooves 35, which are formed after the shrink-fitting of the housing core, are shown again. Fig. 5 closed flow channels 3 are formed in the housing shell, which is not shown. Also in Fig. 5 The second fluid feeds 152 at the second end 102 are visible, which direct the drive fluid from the flow channels 3 into the cylinder bore 15.

[0050] Fig. Figure 5 shows a filter element 7 at the first end 101. The filter element 7 is connected to the closure element 4 via a flange plate 41 and is particularly advantageous in impact or hammer drills to protect the interior of the hydraulic cylinder from foreign objects that may enter the drill string during the drilling process. The filter element 7 is compact and can be easily integrated into a tool.

[0051] Filter element 7 is in Fig. Figure 6 shows a cross-sectional view. The filter element 7 has a connection 74 for a hose or drill string through which a drive fluid can be supplied. The drive fluid then flows through the pipe carrying the connection 74 to its opposite end. The end of the pipe has a plurality of bores 73, which form a screen or can additionally be provided with a screen of a finer mesh. The drive fluid passing through the bores 73 enters a capsule 72 concentrically surrounding the pipe, which is bounded by a wall 71. The drive fluid leaves the capsule 72 through at least one bore 75 in the flange 41 and enters the hydraulic cylinder 1 via the closure element 4. Larger contaminants such as small stones, screws, rust, etc., are trapped by the screen. The flow of the drive fluid is thereby only slightly slowed.

[0052] Naturally, the invention is not limited to the embodiments described. The foregoing description is therefore not to be considered limiting, but rather explanatory. The following claims are to be understood as meaning that a named feature is present in at least one embodiment of the invention. This does not preclude the presence of further features. Where the claims and the foregoing description define "first" and "second" embodiments, this designation serves to distinguish between two similar embodiments without establishing any hierarchy.

[0053] The research that led to this result was funded by the European Union.

Claims

[1] Hydraulic cylinder (1) with a housing (10) with a cylinder bore (15) therein, in which a piston (2) is displaceably mounted, wherein a first fluid supply (151) for supplying a drive fluid into the cylinder bore (15) is arranged at a first end (101) of the housing (10) and a second fluid supply (152) for supplying the drive fluid into the cylinder bore (15) is arranged at a second end (102) of the housing (10), wherein a flow channel (3) extends between the second fluid supply (152) and the first end (101) of the housing (10), characterized by that the housing (10) has a housing core (18) and a housing shell (19), wherein a shrink connection exists between the housing core (18) and the housing shell (19) and at least one longitudinal section of the flow channel (3) is formed by a groove (35) in the housing core (18). [2] Hydraulic cylinder according to claim 1, characterized bythat the outer diameter of the housing core (18) has an oversize of approximately 0.02% to approximately 0.2% or of approximately 0.08% to approximately 0.12% or of approximately 0.09% to approximately 0.11% compared to the inner diameter of the housing shell (19), or that an interference fit of class u6 or better according to ISO 286 is formed between the housing core (18) and the housing shell (19). [3] Hydraulic cylinder according to claim 1 or 2, characterized by that the housing shell (19) is designed in two parts, wherein the two parts of the housing shell (19) are welded together. [4] Hydraulic cylinder according to one of claims 1 to 3, characterized by that an annular groove (185) is provided at the first end and / or at the second end of the housing core (18), which groove is connected to the groove (35) forming the flow channel (3). [5] Hydraulic cylinder according to claim 4, characterized bythat at the first end of the housing (10) there is a closure element (4) which has a line connection (45) which opens into the annular groove (185). [6] Hydraulic cylinder according to one of claims 1 to 5, characterized by that a closure element (4) is arranged at the first end (101) of the housing (10), which closure element has a damping chamber (44) on an inner side facing the cylinder bore (15). [7] Hydraulic cylinder according to claim 6, characterized by that the piston (2) has on its side facing the damping chamber (44) a damper piston (24) which is designed to engage in the damping chamber (44). [8] Hydraulic cylinder according to one of claims 6 or 7, characterized by that at least one vortex chamber (445) is introduced into the side wall (441) of the damping chamber (44) and / or into the damper piston (24). [9] Hydraulic cylinder according to one of claims 1 to 8, characterized bythat at the second end (102) of the housing (10) there is a passage for a push rod which is connected to the piston or that the cylinder bore (15) is closed at the second end (102) of the housing (10). [10] Method for producing a hydraulic cylinder (1) according to one of claims 1 to 9, comprising the following steps: Producing a housing core (18) with an outer surface and with a cylinder bore (15) arranged in the housing core (18) and with a groove (35) made in the outer surface; Producing a housing shell (19) in the form of a tube with an inner surface complementary to the outer surface of the housing core (18); Heating the housing shell (19) and / or cooling the housing core (18); Sliding the housing shell (19) onto the housing core (18); and Enabling temperature equalization of the housing shell (19) and the housing core (18) so that a shrink connection is created between the housing shell (19) and the housing core (18). [11] Method according to claim 10, characterized by that the temperature difference ΔT between the casing shell (19) and the casing core (18) is greater than or equal to ΔT=ΔDD⋅α where ΔD is an oversize of the housing core (18) relative to the housing shell (19), D is the inner diameter of the housing shell (19) and α is the thermal expansion coefficient of the housing shell (19). [12] Method according to one of claims 10 or 11, characterized by that the housing core (18) and / or the housing shell (19) have the basic shape of a circular cylinder. [13] Method according to one of claims 10 to 12, characterized bythat the housing core (18) and the housing shell (19) are manufactured in such a way that the outer diameter of the housing core (18) has an interference fit of approximately 0.02% to approximately 0.2% or of approximately 0.08% to approximately 0.12% or of approximately 0.09% to approximately 0.11% compared to the inner diameter of the housing shell (19), or that an interference fit of class u6 or better according to ISO 286 is formed between the housing core (18) and the housing shell (19). [14] Method according to one of claims 10 to 13, characterized by that the housing shell (19) is designed in two parts, whereby a first part of the housing shell (19) is pushed from a first end of the housing core (18) onto the housing core (18) and a second part of the housing shell (19) is pushed from a second end of the housing core (18) onto the housing core (18) and the first and second parts of the housing shell (19) are welded together. [15] Method according to one of claims 10 to 14, characterized by that an annular groove (185) is introduced at the first end and / or at the second end of the housing core (18), which is connected to the groove (35) forming the flow channel (3). [16] Method according to one of claims 10 to 15, characterized by that the thermal expansion coefficient α of the housing shell (19) between about 7·10 -6 K -1 and about 15·10 -6 K -1 or between about 10·10 -6 K -1 and about 12·10 -6 K -1 amounts. [17] Actuator or hammer drill or harvester vibrator or vibratory compactor with a hydraulic cylinder (1) according to one of claims 1 to 9.

Images