Fluid printing cylinder

Abstract

A piston (18) is slidably arranged inside a cylinder tube (12) of a fluid pressure cylinder (10). A piston cover (22) made of an elastic material is provided to cover one end face of the piston (18). The piston cover (22) comprises a base section (50) opposite a head cover (14) of the cylinder tube (12), a guide section (52) covering an outer circumferential surface of the piston (18) and in sliding contact with an inner circumferential surface of a cylinder bore (28), and a hook section (54) folded over an inner circumferential side relative to the guide section (52). When the piston (18) is moved toward the head cover (14), impacts are absorbed by the base section (50) striking the head cover (14).When the piston (18) is moved along the cylinder tube (12), the guide section (52) serves to guide the piston (18) in the axial direction by sliding contact with the cylinder guide (28).

Description

Background of the invention

[0001] The present invention relates to a fluid pressure cylinder for displacing a piston in an axial direction by supplying a pressure fluid.

[0002] Up to now, a fluid pressure cylinder has been used, for example, as a means of transporting workpieces or the like. This cylinder has a piston that is moved by the supply of a pressurized fluid. In such a fluid pressure cylinder, as described, for example, in German utility model DE 20 2005 013 185 U1, a piston is slidably arranged inside a tubular cylinder, with a piston rod connected to the piston. The piston is moved by the supply of a pressurized fluid. A damper made of an elastic material is attached to one end face of the piston to dampen impacts when the piston strikes a wall surface at its end of travel. Furthermore, a piston seal, provided on the outer circumferential surface of the piston, is formed integrally with the damper.

[0003] In a fluid pressure cylinder described in Japanese patent publication JP 10-238512 A, a buffer retaining groove is machined into an end face of the piston by cutting or similar means. A rubber cushion, serving as a damper, is installed in the annular buffer retaining groove. Furthermore, a piston seal and a wear ring are installed in annular grooves formed on the outer circumferential surface of the piston. Summary of the invention

[0004] In the fluid pressure cylinder according to DE 20 2005 013 185 U1, the installation groove for attaching the damper is formed on the end face of the piston. A separate installation groove for attaching the guide element is formed on the outer circumferential surface of the piston. This necessitates increasing the piston length to accommodate the two different installation grooves. This, in turn, increases the overall length of the fluid pressure cylinder. Furthermore, since the damper and piston seal are formed as a single unit, even if the required properties, such as material and hardness, differ between the damper and piston seal, they must still be manufactured from the same material. This raises concerns that the required properties may not be achieved.

[0005] In the case of the fluid pressure cylinder according to JP 10-238512 A, it is also necessary to produce the buffer body retaining groove in the end face of the piston using a cutting process, which increases manufacturing costs. Furthermore, when the piston seal and wear ring are attached to the piston, the assembly process is difficult because the outer diameters of the ring grooves for their installation essentially correspond to the outer diameter of the piston. This also increases manufacturing costs.

[0006] Furthermore, there has recently been an increasing need to reduce the number of parts in fluid pressure cylinders and to improve manufacturability by improving assembly and work efficiency when assembling the fluid pressure cylinders.

[0007] It is an object of the present invention to propose a fluid pressure cylinder which can reduce manufacturing costs and simplify assembly.

[0008] This problem is essentially solved by the invention through the features of claim 1.

[0009] Advantageous embodiments of the invention are the subject of the dependent claims.

[0010] The present invention is characterized by a fluid pressure cylinder with a cylinder base body in which a pair of ports for the supply and discharge of a pressure fluid and a cylinder chamber into which the pressure fluid is introduced from the ports are formed, a piston on which a piston seal is attached in an installation groove formed on an outer circumferential surface of the piston and which is arranged axially displaceable inside the cylinder chamber, and a cover element attached to an end side of the piston and having a damper section that absorbs shocks caused when the piston, at its displacement end where the piston is displaced to one end of the cylinder base body, strikes the cylinder base body.A groove section, to which the cover element is attached, is formed on the outer circumferential surface of the piston and arranged next to the installation groove, wherein an outer diameter of the groove section is smaller than an outer diameter of the piston.

[0011] According to the present invention, in the fluid pressure cylinder the cover element is attached to an end side of the piston, which is arranged in the cylinder chamber of the cylinder base body, wherein the damper section is provided on the cover element to absorb shocks that are caused when the piston strikes the cylinder base body at a displacement end position, in which the piston is displaced to the end of the cylinder base body.

[0012] By attaching the cover element to one end of the piston, shocks generated at the end of the stroke are absorbed by the damping section. Since the outer diameter of the groove section to which the cover element is attached is small compared to the installation groove formed on the outer circumference of the piston, in which the piston seal is installed, the piston seal can be easily fitted into the installation groove next to the groove section.

[0013] Since the groove section is formed on the outer circumferential surface of the piston to facilitate the installation of the cover element, along with the damping section, it is therefore unnecessary to form the groove section on an end face of the piston using a cutting process (e.g., face milling). This reduces manufacturing costs and improves machinability, thereby simplifying the assembly of the piston seal.

[0014] Further features, functions and advantages of the present invention will become apparent from the following description of an exemplary embodiment and the drawings. All features described and / or illustrated, individually or in combination, constitute the subject matter of the invention, irrespective of their compilation in the claims or their cross-reference. Brief description of the drawings

[0015] Fig. 1 is a section through a fluid pressure cylinder according to an embodiment of the present invention;

[0016] Fig. Figure 2 is an explosive section showing a condition in which a piston cover is removed from a piston of the fluid pressure cylinder according to Fig. 1 has been taken; and

[0017] Fig. Figure 3 is an enlarged section showing the area around the piston and piston cover. Fig. 1 shows. Description of preferred embodiments

[0018] As in Fig. As shown in 1, a fluid pressure cylinder comprises 10 a cylinder tube (cylinder base body) 12 , which is cylindrical or tubular in shape, a head covering 14 , located at one end of the cylinder tube 12 A pole cover is appropriate. 16 , which are located at the other end of the cylinder tube 12 appropriate is to use a piston 18, which is movable inside the cylinder tube 12 is arranged, a piston rod 20 , which are connected to the center of the piston 18 is connected, and a piston cover (cover element) 22 , located at one end (in the direction of arrow A) of the piston 18 appropriate.

[0019] A first connection 24 and a second connection 26 They open at positions near one or the other end of the outer circumferential side of the cylinder tube. 12 A switching device for changing the supply of a pressurized fluid is connected, for example, to the first and second connections via a pipeline (not shown). 24 , 26 connected. The pressure fluid is optionally connected either to the first connection. 24 or the second connection 26 supplied.

[0020] Furthermore, inside the cylinder tube 12a cylinder bore (cylinder chamber) 28 formed, through which it passes in the axial direction (the direction of arrows A and B). The cylinder bore 28 stands above connecting passages 30a , 30b with the first and second connections 24 , 26 in connection.

[0021] The head covering 14 is produced by pressing a flat body from a metallic material, such as aluminum or the like, in such a way that when inserted into the cylinder bore 28 an outer edge section at a defined angle relative to the axis of the cylinder bore 28 is inclined radially outwards in order to thereby penetrate the inner circumferential surface of the cylinder bore 28 to bite into and be attached to it. As a result, the head covering 14 near one end of the cylinder bore 28in this fixed in a state in which it connects the cylinder bore 28 and the surrounding area is blocked.

[0022] The pole cover 16 is at another end (in the direction of arrow B) of the cylinder bore 28 inserted and is located inside the cylinder bore 28 through a locking ring 32 held, which is in engagement with the inner circumferential surface of the cylinder bore 28 is held.

[0023] In an annular groove on an outer circumferential surface of the rod cover 16 is a sealing ring 34 attached. Through the sealing ring. 34 The leakage of pressurized fluid between the cylinder tube will be addressed. 12 and the pole cover 16 prevented. Furthermore, a rod opening passes through. 36 the pole cover 16 in their middle, and the piston rod 20 It can be moved through the rod opening.36 used. A rod seal. 38 , which are located on an inner circumferential surface of the rod opening 36 where it is attached, is in sliding contact with the outer circumferential surface of the piston rod. 20 , causing a leakage of pressurized fluid between the rod cover 16 and the piston rod 20 is prevented.

[0024] As in the Fig. 1 to Fig. As shown in 3, the piston 18 a cross-section which corresponds to the cross-sectional shape of the cylinder bore 28 This corresponds to a piston bore in its center. 40 formed, into which an end section of the piston rod 20 It is inserted and secured by widening (crimping). An installation groove. 42 , in which a piston seal 44 It is attached to the outer circumferential surface of the piston. 18 provided. The piston seal 44is located near an essentially central position between one end face and another end face of the piston 18 arranged.

[0025] Furthermore, on the outer circumferential surface of the piston 18 a first step section (first groove section) 46 , which is set back from the outer circumferential surface by a defined depth, formed on the side of an end surface (in the direction of arrow A), which forms the head cover 14 is facing. A second step section (second groove section) 48 , which is relative to the first stage section 46 If it is reset further, it is next to the installation slot. 42 trained. Both the first and second stages of the program. 46 , 48 are ring-shaped, with the second stage section 48 with the installation groove 42 is connected. In detail, as in Fig. Figure 2 shows the outer diameter D1 of the piston. 18 the largest, the outer diameter D2 of the first stage section 46 is smaller than the outer diameter D1, and the outer diameter D3 of the second stage section 48 is smaller than the outer diameter D2 (D1 > D2 > D3).

[0026] The piston rod 20 It consists of a shaft with a fixed length in the axial direction (in the direction of arrows A and B), one end of which has a reduced diameter. The thinner end is enclosed by the piston bore. 40 of the piston 18 inserted and then deformed and widened in diameter, causing one end to fit into the piston bore. 40 is connected. The other end of the piston rod 20 (in the direction of arrow B) is held movable by passing through the rod opening 36 the pole cover 16 is used.

[0027] The piston cover 22 includes a disc-shaped base body section (damping section) 50 , which consists, for example, of an elastic material such as rubber or urethane, etc., a guide section 52 , which is located on an outer edge section of the base body section 50 is formed and at a right angle relative to the base body section 50 is bent, and has a hook section 54 , which leads to an inner circumferential side at the end of the guide section 52 is folded over. Specifically, the hook section shows 54 a defined distance from the base body section 50 in the thickness direction (the direction of arrows A and B) of the piston cover 22 on and is essentially parallel to the base body section 50 formed. In addition, the basic body section 50 , the leadership section 52 and the hook section 54on the piston cover 22 essentially a constant thickness.

[0028] The basic body section 50 is applied against one end face of the piston. 18 brought. The guided section 52 It is installed in such a way that it covers the outer perimeter of the first step section. 46 covers, and the hook section 54 It is attached in such a way that it covers the outer perimeter of the second step section. 48 covers, interlocking with the second stage section 48 so that the piston cover 22 integral to the piston 18 appropriate.

[0029] At this time, the outer circumferential surface of the guide section 52 shaped so that they cover some of the outer circumferential surface of the piston 18 protrudes, so that when the piston 18 and the piston cover 22 into the cylinder bore 28to be used, the outer circumferential surface of the guide section 52 in sliding contact with the inner circumferential surface of the cylinder bore 28 stands. Accordingly, the piston 18 guided in the axial direction (the direction of arrows A and B), so that when the piston 18 to the head covering 14 (in the direction of arrow A) is moved, the piston cover 22 on the head covering 14 strikes without the piston 18 comes into direct contact with this person.

[0030] The fluid pressure cylinder 10 According to the present invention, the structure is essentially as described above. Next, the installation of the piston cover will be described. 22 at one end face of the piston 18 briefly explained.

[0031] First, as in Fig. 2 shows the piston cover 22 arranged so that they meet one end face of the piston18 opposite, and the side of the hook section 54 (in the direction of arrow A) of the piston cover 22 is close to the piston 18 moved. Next, the piston cover will be removed. 22 in a deformed state, in which the hook section 54 slightly radially outwards and expanded, to the second stage section 48 moved, crossing the outer circumference of the first step section 46 occurs. At the same time, the basic body section 50 the piston 18 approached and positioned against one end face of the piston 18 brought.

[0032] By releasing the deformation of the hook section 54 will then the hook section 54 due to the elasticity of the hook section 54 in interaction with the second stage 48 brought. Accordingly, the basic body section lies 50the piston cover 22 on one surface of the piston 18 on, the leadership section 52 is on the outer perimeter of the first step section 46 arranged, and the hook section 54 is interfering with the second stage 58 This brings the piston cover. 22 integral to the piston 18 attached.

[0033] Next, the operating principle and advantages of the fluid pressure cylinder will be discussed. 10 , in which the aforementioned piston cover 22 on the piston 18 appropriate, explains. As in Fig. As shown in 1, a state is formed in which the piston 18 to the side of the head cover 14 (in the direction of arrow A) is shifted and the base body section 50 the piston cover 22 on the head covering 14 is referred to as an original position.

[0034] In the initial position, a pressurized fluid is supplied to the first port. 24 by switching a switching device (not shown), the pressure fluid passes through the connecting passage 30a between the head covering 14 and the piston 18 supplied, thereby the piston 18 to the rod cover 16 (in the direction of arrow B) is pressed and moved. Furthermore, the second connection 26 Open to the environment. Through sliding contact of the guide section. 52 , which is located on the outer circumferential side of the piston 18 is arranged with the inner wall surface of the cylinder bore 28 The piston is used in this process. 18 guided with high precision in the axial direction (in the direction of arrow B). Then the other end face of the piston is 18 in alignment against the end surface of the rod cover 16 brought, and the final displacement position is reached.

[0035] In the event that the piston 18 by supplying pressurized fluid to the second port 26 by switching a switching device (not shown) back to the head cover 14 (in the direction of arrow A) is shifted, on the other hand the pressure fluid is moved through the connection passage. 30b between the rod cover 16 and the piston 18 supplied, thereby the piston 18 to the head covering 14 (in the direction of arrow A). Accordingly, the piston 18 and the piston rod 20 together and integral to the head covering 14 (in the direction of arrow A) is moved and the original position is reached when the base body section hits it. 50 the piston cover 22 on the head covering 14 restored.

[0036] One end face of the piston 18In this case, it comes via the base body section. 50 the piston cover 22 in attachment against the head cover 14 , without one end face of the piston 18 directly on the head covering 14 The damping function buffers (absorbs) impacts that occur during impact. Furthermore, the piston... 18 through the leadership of the command section 52 guided with high accuracy in the axial direction (in the direction of arrow A).

[0037] In the manner described above, the piston cover is used in the present embodiment. 22 , which consists of an elastic material, at one end face of the piston 18 , the head covering 14 is facing, so that the base body section 50 is located on one end surface and that the guide section 52, which is located at the outer edge of the base body section 50 is intended to be in sliding contact with the inner circumferential surface of the cylinder tube. 12 It is. Furthermore, the piston cover has 22 Damping functions when the base body section 50 on the head covering 14 strikes, as well as a guiding function that assists in the movement of the piston. 18 through the guide section 52 is taken over.

[0038] In comparison to a conventional fluid pressure cylinder with a guide element (wear ring) located on the outer circumferential surface of the piston. 18 as provided, can thus be achieved by providing the piston cover 22 The fact that it is equipped with both a damping function and a guiding function reduces the number of parts. This, in turn, reduces the number of assembly steps, thus simplifying the overall assembly process.

[0039] Since no separate guide element is required, it is also not necessary to provide an annular groove for installing such a guide element on the outer circumferential surface of the piston. 18 to train. This allows the piston to 18 They are designed to be thinner in the axial direction. This is combined with the thinner design of the piston. 18 This can also affect the longitudinal dimension of the fluid pressure cylinder. 10 be reduced in size.

[0040] Since the piston cover 22 by attacking the first and second stage sections 46 , 48 , located on the outer circumferential surface of the piston 18 Furthermore, the production costs can be compared, for example, to a case where a groove is cut using a cutting process (e.g., face milling) for the installation of a damper in one end face of the piston. 18is trained, decrease, because the first and second stage sections 46 , 48 can be formed from the side of the outer circumferential surface using a lathe or similar tool.

[0041] If the piston seal 44 from the side of one end face of the piston 18 in the installation groove 42 The first and second step sections are also attached. 46 , 48 Smaller diameters (D2, D3) are provided, which are recessed relative to the outer circumferential surface (outer diameter D1) of one end face. Therefore, it is not necessary to use the piston seal. 44 to extend, and the piston seal 44 can be achieved simply by slightly widening the outer diameter D2 of the first stage section 46 simply in the installation groove 42 , which, in addition to the first and second stage sections 46 , 48is arranged, attached. Accordingly, the installation of the piston seal can be carried out. 44 on the piston 18 to be simplified. After the piston seal 44 was attached, in this case during the installation of the piston cover 22 a piston seal falling off 44 through the piston cover 22 can be reliably prevented.

[0042] Since, compared to a conventional damper, the contact surface (mounting surface) of the base body section 50 the piston cover 22 on the head covering 14 While the load-bearing capacity can be reliably increased, the load per unit area can also be reduced. This, in turn, can extend the service life of the base section. 50 This can be improved, as fatigue of the base body section is prevented. 50This can also be avoided in the case of long usage periods. Furthermore, deviations in the piston's holding position (and original position) can also be prevented. 18 in the axial direction, which is to be feared during such setting processes, are avoided.

[0043] Furthermore, there is no need for a groove on one end face of the piston. 18 to train in order to install the base body section 50 the piston cover 22 to enable this. Since a simple setup of the basic body section is possible. 50 If sufficient, the number of production steps and production costs can be reduced, for example, compared to a conventional fluid pressure cylinder where a groove for the engagement and installation of the damper is produced by face milling.

[0044] Since the base body section 50 the piston cover 22, which serves as a damping section, and is also separate from the piston seal 44 Once formed, the basic body section can finally be accessed 50 and the piston seal 44 They can be made from different materials with varying hardness properties, according to the desired requirements. This allows them to be better adapted to the desired characteristics. QUOTES INCLUDED IN THE DESCRIPTION

[0045] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0046] DE 202005013185 U1 [0002, 0004] JP 10-238512 A [0003, 0005]

Claims

[1] Fluid pressure cylinder with: a cylindrical base body ( 12 ), which has a pair of connectors ( 24 , 26 ) for the supply and discharge of a pressurized fluid and a cylindrical chamber ( 28 ) has, into which the pressure fluid flows from the connections ( 24 , 26 ) is introduced, a piston ( 18 ), on which a piston seal ( 44 ) in an installation slot ( 42 ), which are located on an outer circumferential surface of the piston ( 18 ) is formed, is attached, with the piston ( 18 ) inside the cylinder chamber ( 28 ) is displaceable in the axial direction, and a cover element ( 22 ), which is located at one end of the piston ( 18 ) is attached and includes a damping section ( 50 ) exhibits shocks that are absorbed when the piston ( 18 ) at a displacement end position, at which the piston ( 18) to one end of the cylindrical base body ( 12 ) is displaced on the cylinder base body ( 12 ) strikes, where a groove section ( 46 ), on which the cover element ( 22 ) is attached to the outer circumferential surface of the piston ( 18 ) trained and next to the installation groove ( 42 ) is arranged, wherein an outer diameter of the groove section ( 46 ) is smaller than the outer diameter of the piston ( 18 ). [2] Fluid pressure cylinder according to claim 1, characterized by that the cover element ( 22 ) a leadership section ( 52 ) has which the piston ( 18 ) in the axial direction of the cylinder base body ( 12 ) leads to the fact that the guide section ( 52 ) on an outer edge section of the damping section ( 50 ) is provided and installed in such a way that it covers part of the outer circumferential surface of the piston ( 18) covers, and that the damping section ( 50 ) at an end face of the piston ( 18 ) is located perpendicular to a displacement direction of the piston ( 18 ) is oriented. [3] Fluid pressure cylinder according to claim 2, characterized by that the cover element ( 22 ) also a hook section ( 54 ) exhibits, which is located at one end of the guide section ( 52 ) is provided and relative to the guide section ( 52 ) to an inner circumferential side of the piston ( 18 ) is folded over. [4] Fluid pressure cylinder according to claim 3, characterized by that another groove section ( 48 ), which extends radially inwards relative to the groove section ( 46 ) is reset and at which the hook section ( 54 ) is attached to the outer circumferential surface of the piston ( 18 ) between the groove section ( 46 ) and the installation groove ( 42 ) is planned. [5] Fluid pressure cylinder according to claim 4, characterized by that the outer groove section ( 48 ) has an outer diameter that is larger than that of the installation groove ( 42 ). [6] Fluid pressure cylinder according to one of the preceding claims, characterized by that the damping section ( 50 ) is arranged so that it forms an end face of the piston ( 18 ), which are perpendicular to a displacement direction of the piston ( 18 ) is oriented, covers. [7] Fluid pressure cylinder according to one of the preceding claims, characterized by that the cover element ( 22 ) is made of an elastic material.