Fluid printing cylinder

Abstract

A fluid pressure cylinder (10) comprising: a cylindrical base body (12) in which a cylindrical chamber (13) is formed, to which a pressure fluid is supplied; a piston (40, 140) connected to a piston rod (50), wherein the piston (40, 140) is displaceable in an interior of the cylinder chamber (13) in the axial direction of the cylinder base body (12); a cap (20, 120, 220) for blocking an open end of the cylinder chamber (13) which is arranged in the cylinder base body (12); and a rod end (30) that blocks another open end of the cylinder chamber (13), wherein: a first pressure fluid inlet or outlet port (16) is provided in the vicinity of one open end of the cylinder chamber (13), which is connected to the cylinder chamber (13) in the cylinder base body (12); a second pressure fluid inlet or outlet port (18) is provided in the vicinity of the other open end of the cylinder chamber (13), which is connected to the cylinder chamber (13) in the cylinder body (12); characterized by the fact that the cap comprises (20, 120, 220): a flat base body section (22, 122, 222) on which an end surface of the piston (40,140) abuts and an outer edge section (24, 124, 224) which is provided on an outer circumference of the base body section (22, 122, 222), wherein the outer edge section (24, 124, 224) is bent from the base body section (22, 122, 222) to one open end of the cylindrical chamber (13) and wherein a distal end (26, 126) of the outer edge section (24, 124, 224) is locked to an inner circumferential wall (15) of the cylindrical chamber (13); When the end face of the piston (40, 140) comes into contact with the base body section (22, 122, 222), a space (S1) is formed which is surrounded by the outer edge section (24, 124, 224) of the cap (20, 120, 220) in a state in which the end face of the piston (40, 140) is in contact with the base body section (22, 122, 222), the inner circumferential wall (15) of the cylinder chamber (13) and the end face of the piston (40, 140) in the state in which the end face of the piston (40, 140) is in contact with the base body section (22, 122, 222); and The space (S1) is connected to the first pressurised fluid inlet or outlet port (16).

Description

Background of the invention: Area of ​​the invention:

[0001] The present invention relates to a fluid pressure cylinder which, through the action of a pressure fluid, causes the displacement of a piston along axial directions. Description of the state of the art:

[0002] Previously, a fluid pressure cylinder was used as a means of driving various types of industrial machines, such as workpiece transport and positioning devices or the like.

[0003] DE 41 22 481 A1 discloses a piston-cylinder arrangement comprising a piston with two piston discs spaced apart by a damper. A round magnet and a radial seal are installed between the two piston discs. A magnetically responsive sensor for detecting the piston's position is located on the outer wall of the cylinder.

[0004] Document DE 10 2011 015 682 A1 discloses a cap for use in a fluid pressure device and a fastening method for it.

[0005] In general, a fluid pressure cylinder causes a piston, located inside a cylinder body, to be moved axially by the action of a pressurized fluid supplied from a pressurized fluid port. This movement facilitates the transport, positioning, or similar operations of workpieces via a piston rod connected to one end of the piston. With regard to such cylinders, there has recently been a requirement to minimize the size of the fluid pressure cylinder, and in particular to shorten its length (overall length of the fluid pressure cylinder) in the axial direction, while maintaining the stroke length of the piston (piston rod).

[0006] Based on these requirements in the prior art, the present applicant has proposed a fluid pressure cylinder whose overall length is reduced, while maintaining the stroke length of the fluid pressure cylinder by closing an opening in the cylinder body with a substantially flat cap and having the piston strike the cap when the piston reaches a displacement end position (compare Japanese patent publication no. 2005-240936).

[0007] As in Fig. As shown in Figure 11, a stepped section 3 is provided in such a fluid pressure cylinder by carrying out a step formation process on an end face of the piston 2 that is opposite the cap 1. When the piston 2 comes into contact with the cap 1, a space (air passage) S2 is formed through which the pressure fluid can be introduced between the cap 1 and the piston 2. Summary of the invention

[0008] The present invention aims to propose a fluid pressure cylinder in which a chamber into which a pressure fluid can be introduced is formed inside a cylinder body, without the need for a stepped section at an end face of the piston or an end face of the cap, while also allowing the overall length of the fluid pressure cylinder to be shortened while maintaining the stroke length of the piston. This further promotes and supports the miniaturization of the fluid pressure cylinder.

[0009] This problem is solved by a fluid pressure cylinder with the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

[0010] When the piston comes to rest against the cap, a space can be formed, according to the present invention, even without forming a stepped section at the end face of the piston, through which the pressure fluid can be introduced into the interior of the cylinder chamber. Accordingly, the length of the piston can be shortened by the width dimension corresponding to the stepped section, and the overall length of the fluid pressure cylinder can be made shorter. This allows for a more compact fluid pressure chamber.

[0011] Since a process for forming the stepped section is no longer necessary, the number of manufacturing steps can also be reduced. This lowers manufacturing costs and improves production efficiency accordingly.

[0012] Furthermore, an outer edge section of the cap is bent towards the open end of the cylinder chamber, and the distal end of this outer edge section is locked to the inner circumferential wall of the cylinder chamber. When the cap is pressed by the colliding piston, the pressing force causes the distal end of the outer edge section to bite further into the inner circumferential wall of the cylinder chamber. As a result, the cap can effectively absorb shocks from the piston. Compared to the prior art, the wall thickness of the cap, which is necessary to ensure the cap's strength, can therefore be made thinner in the axial direction. Consequently, the overall length of the fluid pressure cylinder can be reduced.

[0013] Furthermore, an end surface facing the cap can be provided in a planar form perpendicular to the axial direction of the cylindrical base body.

[0014] Since, in the design described above, the cap can absorb shocks when the piston strikes the entire base section of the cap, which has the flat end surface, the cap is even better able to absorb shocks applied by the piston. Compared to the prior art, the wall thickness of the cap, which is necessary to ensure the cap's strength, can therefore be made even thinner in the axial direction. As a result, the overall length of the fluid pressure cylinder can be shortened.

[0015] Furthermore, the space into which a pressure fluid can be introduced can be ring-shaped with a triangular cross-section.

[0016] In the setup described above, even if the piston is rotated circumferentially within the cylinder chamber, the space bounded by the outer edge of the cap, the inner circumferential wall of the cylinder chamber, and the piston's end face remains connected to the first pressure fluid inlet / outlet port. Consequently, the pressure fluid can be reliably supplied to apply a pressure force to the piston's end face.

[0017] Furthermore, a distal end with a narrow diameter of the first pressure fluid inlet / outlet connection can be completely oriented towards a space that is formed in an annular shape with a triangular cross-section.

[0018] In the setup described above, regardless of the piston's position in the cylinder chamber, the space bounded by the outer edge of the cap, the inner circumferential wall of the cylinder chamber, and the piston's end face, and the first pressure fluid inlet / outlet port, remain in constant contact. Consequently, the pressure fluid can be reliably supplied to the piston's end face, and the piston can be moved smoothly back and forth.

[0019] The present invention achieves the following advantages and modes of operation.

[0020] Specifically, a simple design allows a space (air passage) to be created when the piston comes into contact with the cap. This enables the introduction of the pressurized fluid into the cylinder chamber. Consequently, there is no need to perform a process to form a stepped section on the end face of the piston or the end face of the cap, which would reduce the axial length of the piston or cap by one dimension in the lateral direction equal to the thickness of the stepped section. As a result, the overall length of the fluid pressure cylinder can be shortened. This allows for the production of a more compact fluid pressure cylinder.

[0021] The above and further tasks, features and advantages of the present invention will become even clearer from the following description in conjunction with the accompanying drawings, in which a preferred embodiment of the invention is illustrated by way of example. Brief description of the drawings Fig. Figure 1 is a vertical section through a fluid pressure cylinder according to an embodiment of the present invention; Fig. Figure 2 is a perspective view of a single cap body, which is in Fig. 1 is shown; Fig. 3 is an enlarged partial section in the vicinity of the cap, in which in Fig. 1 fluid pressure cylinder shown; Fig. 4 is an enlarged partial section showing a condition in the vicinity of the cap according to Fig. 1 shows where the piston and the cap are in contact; Fig. 5 is an enlarged partial section showing a condition in the vicinity of the cap according to Fig. 1 shows where the piston and the cap are somewhat separated from each other; Fig. 6 is an enlarged partial section taken in the vicinity of the cap according to Fig. 1 shows a state in which the piston and the cap are separated from each other; Fig. 7A is an enlarged partial section showing a state in which, according to the present invention, a plate is inserted into a cylindrical chamber and arranged between a first mandrel and a second mandrel; Fig. 7B is an enlarged partial section showing a state in which the diameter of the plate is increased by the first mandrel and the second mandrel in order to form the cap; Fig. 8A is an enlarged partial section which, in a first modification, shows a state in which a plate is inserted into the cylinder chamber and arranged between a first mandrel and a second mandrel; Fig. 8B is an enlarged partial section showing a state in which the diameter of the plate is increased by the first mandrel and the second mandrel to form the cap; Fig. 9A is a perspective view of a cap according to a second modification, and Fig. 9B is a cut through the cap; Fig. Figure 10 is a vertical section through a fluid pressure cylinder according to a third modification; and Fig. Figure 11 is a vertical section through a fluid pressure cylinder according to Japanese patent disclosure no. 2005-240936. Detailed description of preferred embodiments

[0022] A preferred embodiment of a fluid pressure cylinder according to the present invention is described in detail below with reference to the accompanying drawings. Fig. Reference numeral 10 designates a fluid pressure cylinder according to an embodiment of the present invention.

[0023] As in Fig. As shown in Figure 1, the fluid pressure cylinder 10 is formed by a cylinder tube (cylinder body) 12 with a first port (first pressure fluid inlet / outlet port) 16 and a second port (second pressure fluid inlet / outlet port) 18, through which a pressure fluid (e.g., compressed air) is supplied and discharged, a plate-shaped (flat) cap 20 that blocks one opening (open end) of the cylinder tube 12, a rod end 30 that blocks another opening (open end) of the cylinder tube 12, a piston 40 that is arranged inside the cylinder tube 12 for displacement in the axial directions, and a piston rod 50 that is connected to one end of the piston 40.

[0024] The cylinder tube 12 is formed in a cylindrical shape from a metal material, such as aluminum or the like. The first connection 16 is formed on an outer circumferential surface at one end (in the direction of arrow A) of the cylinder tube 12, and the second connection 18 is formed on an outer circumferential surface at the other end (in the direction of arrow B), located at a defined distance from the first connection 16. Furthermore, the first connection 16 and the second connection 18 are each connected via a first connecting passage 19a and a second connecting passage 19b, respectively, to a cylindrical chamber 13 formed inside the cylinder tube 12.

[0025] As in Fig. As shown in Figure 2, the cap 20 is formed, for example, by pressing a plate 60 made of a metallic material, such as aluminum or the like, and consists of a disk-shaped base body section 22 and an outer edge section 24, in which the outer circumference of the base body section 22 is bent at a defined angle to the axis and extended radially outwards. Furthermore, as shown in Fig. As shown in Figure 3, the outer edge section 24 of the cap 20 is arranged such that it is opposite one opening (in the direction of arrow A) of the cylinder tube 12, and in particular such that it faces one side opposite the rod end 30.

[0026] Furthermore, the outer diameter D2 of the outer edge section 24 of the cap 20 is chosen to be slightly larger than the inner diameter D1 of the cylinder chamber 13. When the cap 20 is fitted into one opening of the cylinder tube 12, the outer edge section 24 of the cap 20 is positioned so that it bites into an inner circumferential wall 19 of the opening. More precisely, a distal end 26 of the outer circumferential side, which forms the outer edge section 24, bites into the inner circumferential wall 15 of the cylinder tube 12 to a defined depth, thereby securely fixing the cap 20 inside the opening.

[0027] Furthermore, the cap 20 is made of a metallic material and shaped in the same way as the cylinder tube 12. Additionally, the hardness E1 of the cap 20 is chosen to be greater than the hardness E2 of the cylinder tube 12 (E1 > E2).

[0028] Furthermore, a surface treatment, such as an aluminite treatment (i.e., an anodic oxidation coating on aluminum or aluminum alloys) or the like, is applied to the cap 20. The thickness of the treated layer formed by the surface treatment is set, for example, between approximately 5 and 30 µm. Moreover, the surface treatment performed on the cap 20 is not limited to the aforementioned aluminite treatment and can, for example, also be a chromate treatment or a coating.

[0029] As in Fig. As shown in Figure 1, the rod end 30 comprises a small-diameter section 31 and an adjacent large-diameter section 32. The small-diameter section 31 is located in the cylinder tube 12 on the side of the cap 20 (in the direction of arrow A). Furthermore, a snap ring 33 is fitted in a first annular groove 14 formed in the inner circumferential wall 15 of the cylinder tube 13 such that the snap ring 33 abuts an end face of the large-diameter section 32, and the rod end 30 is fixed in a position inside the cylinder chamber 13.

[0030] A rod opening 34 is formed in a central section of the rod end 30, extending axially (in the direction of arrows A and B). The piston rod 50 is inserted through the rod opening 34. A second annular groove 35 is also formed in the rod end 30, its diameter widening from the rod opening 34, and a rod seal 36 is fitted in the second annular groove 35. The rod seal 36 rests against the outer circumferential surface of the piston rod 50, thus maintaining an airtight seal inside the cylinder chamber 13. Furthermore, an O-ring 38 is fitted in a third annular groove 37 on the outer circumferential surface of the large-diameter section 32 of the rod end 30.

[0031] The piston 40 is arranged inside the cylinder tube 12 and is axially displaceable. A piston seal 43 is fitted into a fourth annular groove 42 on the outer circumferential surface of the piston 40. The piston seal 43 divides the cylinder chamber 13 into a cap-side cylinder chamber 13a and a rod-end-side cylinder chamber 13b.

[0032] Furthermore, a piston opening 44 is formed within the piston 40, which extends through the piston 40 in the axial direction (in the direction of arrows A and B). A connecting section 52 of the piston rod 50 is inserted through the piston opening 44. The piston opening 44 comprises a cap-side piston opening 44a, which opens in a tapered shape, its diameter widening towards the side of the cap 20 (in the direction of arrow A), and a rod-end-side piston opening 44b, which is connected to the cap-side piston opening 44a and opens with the same diameter towards the side of the rod end 30 (in the direction of arrow B). The connecting section 52 of the piston rod 50, after being inserted through the rod-end piston opening 44b, is plastically defined in such a way that it blocks the cap-side piston opening 44a, and is formed in a planar shape perpendicular to the axial direction of the cylinder base body 12.This ensures that the end surface of the piston 40, which faces the cap 20, is also flat and perpendicular to the axial direction of the cylinder base body 12.

[0033] According to the present invention, when the end face of the piston 40, which faces the cap 20, abuts the base body section 22 of the cap 20, a small space (air passage) S1 is formed, which is bounded by the outer edge section 24 of the cap 20, the inner circumferential wall 15 of the cylinder chamber 13 and the end face of the piston 40, i.e. a small space (air passage) S1, through which the pressurised fluid can be introduced into the cylinder chamber 13.

[0034] Room S1 is connected to the first connection 16 via the first connecting passage 19a.

[0035] As in Fig. As shown in Figure 1, the chamber S1 is also annular with a triangular cross-section. Therefore, even when the piston 40 is rotated circumferentially inside the cylinder chamber 13, the chamber S1 remains continuously connected to the first port 16. Accordingly, the pressure fluid can be reliably supplied to apply a pressure force to the end face of the piston 40.

[0036] Furthermore, the first connecting passage 19a has a smaller diameter than the opening of the first connection 16, which is provided on the outer circumference of the cylinder tube 12, so that the opening (distal end) of the first connecting passage 19a faces entirely into the chamber S1. Specifically, the diameter of the opening (distal end) of the first connecting passage 19a is shaped such that it is shorter than one side of the chamber S1, which has a triangular cross-section, in the inner circumferential wall 15 of the cylinder chamber 13. This design ensures that the pressurized fluid is reliably supplied to the end face of the piston 40, enabling the reciprocating movement of the piston 40.

[0037] The fluid pressure cylinder 10 according to the embodiment of the present invention is essentially constructed as described above. Next, an assembly process is described in which the cap 20 is attached to the cylinder tube (cylinder base cap) 12, with reference to the Fig. 7A and Fig. 7B described.

[0038] First, in a state in which the piston 40 and the piston rod 50 are not inserted through the cylinder chamber 13 into the interior of the cylinder tube 12, the cylinder tube 12 is positioned in a preparation state such that the opening at one end of the cylinder tube 12 is oriented upwards.

[0039] In this preparatory state, a first mandrel (forming element) 70 is inserted into the cylinder chamber 13 from the other opening, i.e., from the lower side, of the cylinder tube 12 such that one end of the first mandrel 70 is positioned at an installation position of the cap 20 in the cylinder chamber 13. The first mandrel 70 is formed by a shaft whose end has a flat shape. The diameter of the first mandrel 70 is chosen to be slightly smaller than the inner diameter D1 of the cylinder chamber 13. At this stage, the first mandrel 70 and the cylinder chamber 13 are aligned on the same axis, and the end face of the first mandrel 70 is substantially perpendicular to the axis of the cylinder chamber 13.

[0040] Next, the plate 60, which will form the base of the cap 20, is inserted from the side of one opening, i.e., from the top, of the cylindrical chamber 13. The plate 60 has a curved cross-section and a substantially constant thickness. Furthermore, the outer diameter of the plate 60 is shaped such that it is substantially the same diameter as, or slightly smaller than, the inner circumferential diameter D1 of the cylindrical chamber 13.

[0041] In other words, the cross-sectional area of ​​the plate 60 is chosen such that it is at least substantially equal to or smaller than the cross-sectional area of ​​the cylindrical chamber 13.

[0042] Furthermore, the plate 60 is inserted into the cylinder chamber 13 such that its pre-curved central section is oriented downwards and that the plate 60 is in a state where it is attached to the end face of the first mandrel 70. Since the outer diameter of the plate 60 is essentially the same as or slightly smaller than the inner diameter D1 of the cylinder chamber 13, the plate 60 is inserted into the cylinder chamber 13 without touching the inner circumferential wall 15 of the cylinder chamber 13. Accordingly, damage to the inner circumferential wall 15 by the plate 60 is avoided.

[0043] Finally, a second mandrel (forming element) 80, whose distal end has a tapered shape 81, is inserted from the side of one opening, i.e., from the upper side of the cylindrical chamber 13, and lowered with a defined pressure. Similar to the first mandrel 70, the second mandrel 80 consists of a shaft with a flat lower end surface. The diameter of the lower end surface is chosen to be smaller than the diameter of the first mandrel 70.

[0044] Lowering the second mandrel 80 also grips and presses the plate 60 between the end face of the second mandrel 80 and the end face of the first mandrel 70. As a result of this pressing force, as described in Fig. As shown in Figure 7B, the flat base body section 22 is formed between the first mandrel 70 and the second mandrel 80, and the outer circumferential section of the plate 60 is bent upwards by the action of the tapered shape 81 to form the outer edge section 24 of the cap 20. In other words, the area of ​​the plate 60 gripped by the first mandrel 70 and the second mandrel 80 becomes the flat base body section 22. Furthermore, the outer circumferential section of the base body section 22, i.e., the area whose diameter is expanded radially outwards and plastically deformed upwards, becomes the outer edge section 24. This shapes the plate 60 into the cap 20.

[0045] At this time, as a result of the outer edge section 24 expanding radially outwards and being plastically deformed upwards, the outer diameter D2 of the outer edge section 24 of the cap 20 becomes larger than the inner diameter D1 of the cylinder chamber 13 (D2 > D1). This causes the distal end 26 of the outer edge section 24 to bite into and lock into the inner circumferential wall 15 of the cylinder chamber 13, thereby fixing the cap 20 to the cylinder tube 12.

[0046] As a consequence of the fact that the cap 20 is attached to the cylinder tube (cylinder base body) 12 in this manner, when the end face of the piston 40 comes into contact with the base body section 22 of the cap 20, the space (air passage) S1, through which the pressurized fluid can be introduced into the cylinder chamber 13, is formed by the outer edge section 24 of the cap 20, the inner circumferential wall 15 of the cylinder chamber 13 and the end face of the piston 40 (compare Fig. 1) In detail, without performing a process to form a stepped section, the small space (air passage) S1 can be formed through which the pressure fluid can be introduced into the cylinder chamber 13. Due to the fact that a dimension in the width direction can be omitted corresponding to the stepped section, the length in the axial direction of the piston 40 or the cap 20 can be shortened accordingly, and the overall length of the fluid pressure cylinder 10 can also be shortened.

[0047] Since the staged training process is no longer necessary, the number of manufacturing steps can also be reduced. Consequently, production efficiency can be improved and manufacturing costs reduced.

[0048] Furthermore, the outer edge section 24 of the cap 20 is bent towards the open end of the cylinder chamber 13, and the distal end 26 of the outer edge section 24 engages and locks the inner circumferential wall 15 of the cylinder chamber 13. When the cap 20 is pressed by the piston 40 and collides with it, the pressing force causes the distal end 26 of the outer edge section 24 to bite even more firmly into the inner circumferential wall 15 of the cylinder chamber 13. As a result, the cap 20 is able to absorb shocks from the piston 40 effectively. Compared to the prior art, the wall thickness of the cap 20, which is necessary to ensure its strength, can therefore be made thinner in the axial direction. Consequently, the overall length of the fluid pressure cylinder 10 can be shortened without reducing the stroke.

[0049] Furthermore, the plate 60 can be inserted into the cylinder chamber 13 without sliding on the inner circumferential wall 15 of the cylinder chamber 13, because the plate 60 has an outer diameter that is slightly smaller than the inner diameter D1 of the cylinder chamber 13. This prevents damage to the inner circumferential wall 15 caused by the plate 60 when it is inserted, and thus the occurrence of minor leaks of pressurized fluid through such a damaged area can be advantageously avoided.

[0050] Since the cap 20 can be fixed at a desired position in the axial direction of the cylinder chamber 13, a locking ring for fixing the cap, which was used in the prior art fluid pressure cylinder, a groove for attaching the locking ring, and an O-ring arranged on the outer circumferential surface of the cap become unnecessary. This reduces the manufacturing costs and the number of components of the fluid pressure cylinder 10, and improves production efficiency.

[0051] Because the outer edge section 24 of the cap 20 is arranged such that it faces one side opposite the cylinder chamber 13, the distal end 26 of the outer edge section 24 is caused to bite even more firmly into the inner circumferential wall 15 of the cylinder chamber 13 by the aforementioned pressure, even when a pressure force of the piston 40 is applied to the cap 20, or when pressure of the pressure fluid in the cylinder chamber 13 is applied and the cap 20 is pressed in one direction away from the cylinder chamber 13. Accordingly, the outer edge section 24 reliably prevents the cap 20 from coming loose from the cylinder tube 12. Specifically, the outer edge section 24 performs a holding function to prevent the cap 20 from coming loose.

[0052] Since the cap 20 undergoes a surface treatment, this surface treatment, coating, or similar process ensures that the cap 20 remains in close contact with the inner circumferential surface 15 of the cylinder chamber 13 within the cylinder tube 12. As a result, even minimal leakage of pressurized fluid between the cap 20 and the cylinder chamber 13 of the cylinder tube 12 can be reliably prevented.

[0053] Since the cap 20 and the cylinder tube 12 are made of the same material, they also have the same coefficient of thermal expansion and the same volumetric expansion ratio with temperature changes. Therefore, even if the fluid pressure cylinder 10 is subjected to a temperature change, no gaps or spaces will form between the cylinder tube 12 and the cap 20. As a result, leakage of pressurized fluid caused by temperature changes can be reliably prevented. Furthermore, since the cap 20 and the cylinder tube 12 can be bonded together, even very small leaks of pressurized fluid passing between the cap 20 and the cylinder tube 12 can be reliably prevented.

[0054] Since the hardness E1 of the cap 20 is chosen to be greater than the hardness E2 of the cylinder tube 12 (E1 > E2), the cap 20 can be fitted, biting into the inner circumferential wall 15 of the cylinder chamber 13. As a result, the cap 20 is reliably and firmly fixed to the cylinder tube 12.

[0055] Furthermore, both the cylinder tube 12 and the cap 20 are made of aluminum. After the cap 20 is attached to the cylinder tube 12, a surface treatment, such as an aluminite treatment or similar, can be applied to both the cylinder tube 12 and the cap 20 simultaneously. As a result, during the surface treatment, the treatment agent enters and penetrates between the cap 20 and the cylinder tube 12, sealing any small gaps between these elements. This prevents even very minor leakage of pressurized fluid and reduces the number of manufacturing steps.

[0056] Because the cap 20 is made of a plate-shaped metal material, even if the piston 40 strikes the cap 20 and is thereby stopped, shocks exerted by the piston 40 can be adequately dampened, because the cap 20 is elastically deformed when the piston strikes it.

[0057] The fluid pressure cylinder 10 according to the embodiment of the present invention is essentially constructed as described above. The operating mode of the fluid pressure cylinder 10 will be explained next.

[0058] As in Fig. Figure 4 shows a state in which the piston 40 rests against the cap 20 and is in close contact with the cap 20 by means of lubricating grease (not shown) applied to the respective end surfaces of the cap 20 and the piston 40, and is explained as an original position.

[0059] Initially, in the original position, a pressurized fluid is supplied to the first port 16 from a pressurized fluid supply source (not shown). In this case, the second port 18 is opened to the environment by actuating a switching valve (not shown).

[0060] The pressurized fluid supplied to the first port 16 is fed through the first connecting passage 19a into the interior of the cylinder chamber 13. Specifically, the pressurized fluid is fed into the space (air passage) S1, which is formed by the outer edge section 24 of the cap 20, the inner circumferential wall 15 of the cylinder chamber 13, and the end face of the piston 40.

[0061] Next, as in Fig. As shown in Figure 5, the pressurized fluid supplied to the chamber (air passage) S1 exerts pressure on the end face of the piston 40 towards the side of the rod end 30 (in the direction of arrow B). As a result, the piston 40, which was in close contact with the base section 22 of the cap 20 via the lubricating grease, is displaced away from the cap 20, and in particular towards the side of the rod end 30 (in the direction of arrow B).

[0062] As the piston 40 moves away from the base body section 22 of the cap 20, the pressure fluid continues to press against the end face of the piston 40.

[0063] Accordingly, as in Fig. As shown in Figure 6, the piston 40, together with the piston rod 50, is displaced further in one direction (the direction of arrow B) away from the cap 20. Thus, the piston rod 50 is caused to gradually project outwards from the rod end 30, and the end face of the piston 40, which faces the rod end 30, reaches its final displacement position upon contact with the end face of the rod end 30.

[0064] Next, when the piston 40 is returned from the aforementioned end position of displacement to its original position, the pressurized fluid supplied to the first port 16 is fed to the second port 18 via a switching device (not shown). As a result of the pressurized fluid being supplied to the cylinder chamber 13 via the second connection passage 19b, the piston 40 is gradually pressed in a direction (in the direction of arrow A) in which it moves away from the rod end 30. In this case, the first port 16 is in a state where it is open to the environment.

[0065] Along with the displacement of the piston 40, the piston rod 50 is also displaced so that it gradually enters the interior of the rod end 30. Upon contact with the cap 20, the piston 40 is returned to its original position, whereupon the supply of the pressurized fluid is interrupted.

[0066] The plate 60, which forms the cap 20, is not limited to having a curved cross-section as described above. For example, as in Fig. As shown in Figure 8A, a plate 160 is provided which has an outer edge section 124, the outer circumferential region of which has been pre-bent upwards. With regard to such a plate 160, the formation of a cap 120 can be carried out by using a third mandrel 180 which corresponds to the cross-sectional shape of the plate 160 (compare Figure 8A). Fig. 8B).

[0067] Since, in this case, the base body section 122 and the outer edge section 124 were pre-formed on the plate 160, the outer edge section 124 can be formed more reliably and with high precision on the cap 120. Furthermore, when the cap 120 is installed inside the cylinder chamber 18, the distal end 126 of the outer edge section 124 reliably bites into the inner circumferential wall 15 of the cylinder chamber 13. This allows the cap 120 to reliably and firmly engage with the cylinder tube 12 and be locked to it.

[0068] Instead of the aforementioned cap 20 or cap 120, as described in the Fig. 9A and Fig. Figure 9B shows a cap 220 being used which has a base body section 222 with a curved cross-section and an outer edge section 224 which is formed in planar form on the outer circumference of the base body section 222.

[0069] During the Fig. 9A and Fig. As a result of pressing the cap 220 through the first mandrel 70 and the second mandrel 80, the base body section 222 is plastically deformed into a planar form. The base body section 222, together with the outer edge section 224, then undergoes radially outward plastic yielding. Consequently, the cap 220 becomes planar overall, and its outer diameter is increased. The outer edge section 224 of the cap 220 then bites perpendicularly into the inner circumferential wall 15 of the cylindrical chamber 13 and is locked to the inner circumferential wall 15.

[0070] Furthermore, instead of the piston 40 described above, as in Fig. As shown in Figure 10, a piston 140 is used in which a piston opening 144 with a substantially constant diameter is formed, which passes through the piston 40 in the axial direction (the direction of arrows A and B).

[0071] A connecting body 150, which is connected to one end of the piston rod 50, is inserted into the piston opening 144. The connecting body 150 is formed, for example, by pressing a plate element from a metallic material such as stainless steel or the like, and is formed by a disk-shaped base body section 153 and an outer edge section 154, wherein the outer circumference of the base body section 153 is bent at a defined angle to the axis and is radially widened outwards in diameter. The outer edge section 154 of the connecting body 150 is arranged such that it faces an opening (in the direction of arrow A) and, in particular, the side of the cap 20 of the cylinder tube 12.

[0072] The outer diameter of the outer edge section 154 is chosen to be slightly larger than the inner diameter of the piston opening 144. In other words, the outer edge section 154 of the connecting body 150 is positioned so that it bites into the inner circumferential wall of the piston opening 144. Specifically, the distal end 156 of the outer circumferential side of the outer edge section 154 bites into the inner circumferential wall of the piston opening 144 to a defined depth, thereby fixing the connecting body 150 inside the piston opening 144.

[0073] When the piston 140 is moved and comes into contact with the cap 20, the connecting body 150 is elastically deformed, thereby damping impacts applied to the cap 20. Accordingly, compared to the use of the piston 40, the advantage is achieved that the wall thickness of the cap 20, which is necessary to ensure its strength, can be made thinner in the axial direction.

Claims

[1] A fluid pressure cylinder (10) comprising: a cylindrical base body (12) in which a cylindrical chamber (13) is formed, to which a pressure fluid is supplied; a piston (40, 140) connected to a piston rod (50), wherein the piston (40, 140) is displaceable in an interior of the cylinder chamber (13) in the axial direction of the cylinder base body (12); a cap (20, 120, 220) for blocking an open end of the cylinder chamber (13) which is arranged in the cylinder base body (12); and a rod end (30) that blocks another open end of the cylinder chamber (13), wherein: a first pressure fluid inlet or outlet port (16) is provided in the vicinity of one open end of the cylinder chamber (13), which is connected to the cylinder chamber (13) in the cylinder base body (12); a second pressure fluid inlet or outlet port (18) is provided in the vicinity of the other open end of the cylinder chamber (13), which is connected to the cylinder chamber (13) in the cylinder body (12); characterized by , that the cap includes (20, 120, 220): a flat base body section (22, 122, 222) on which an end surface of the piston (40,140) abuts and an outer edge section (24, 124, 224) which is provided on an outer circumference of the base body section (22, 122, 222), wherein the outer edge section (24, 124, 224) is bent from the base body section (22, 122, 222) to one open end of the cylinder chamber (13) and wherein a distal end (26, 126) of the outer edge section (24, 124, 224) is locked to an inner circumferential wall (15) of the cylinder chamber (13); When the end face of the piston (40, 140) comes into contact with the base body section (22, 122, 222), a space (S1) is formed which is surrounded by the outer edge section (24, 124, 224) of the cap (20, 120, 220) in a state in which the end face of the piston (40, 140) is in contact with the base body section (22, 122, 222), the inner circumferential wall (15) of the cylinder chamber (13) and the end face of the piston (40, 140) in the state in which the end face of the piston (40, 140) is in contact with the base body section (22, 122, 222); and The space (S1) is connected to the first pressurised fluid inlet or outlet port (16). [2] The fluid pressure cylinder (10) according to claim 1, wherein an end surface facing the cap (20, 120, 220) is provided on the piston (40, 140) in a planar form perpendicular to the axial direction of the cylinder base body (12). [3] The fluid pressure cylinder (10) according to claim 1, wherein the space (S1) is annular with a triangular cross-section. [4] The fluid pressure cylinder (10) according to claim 3, wherein a distal end (19a) with a small diameter of the first pressure fluid inlet or outlet port (16) is completely directed towards the space (S1) which is annular with a triangular cross-section.

Images