JP2017194087A - Pressure resistant apparatus and fluid pressure cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability of a cylinder.SOLUTION: A cylinder 100 includes a cylinder tube 110, and a cylinder bottom 120 closing an opening of the cylinder tube 110. Annular grooves 114, 124 extending in a circumferential direction are formed on inner surfaces 110b, 122b of the cylinder tube 110 and a wall 122 of the cylinder bottom 120, and inside diameters D3, D4 of the grooves 114, 124 are larger than an inside diameter D2 of an opening end 110a of the cylinder tube 110 and an inside diameter D1 of an end 122a of the wall 122.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pressure-resistant device and a fluid pressure cylinder.

  Patent Document 1 discloses a hydraulic cylinder which is a kind of pressure-resistant device. In this hydraulic cylinder, an annular wall portion is formed at the cylinder bottom, and the annular wall portion of the cylinder bottom and the cylinder tube are joined by welding.

Japanese Examined Patent Publication No. 2-53643

  In the cylinder (pressure-resistant device) disclosed in Patent Document 1, a protrusion may be formed on the inner peripheral surface of the cylinder by a joint portion formed by welding the cylinder tube and the annular wall portion. When an axial force is applied to the cylinder in a state where the protrusion is formed, stress concentrates at the base of the protrusion, and the cylinder may be damaged. There is a need for a cylinder that has sufficient durability even when the protrusions are formed.

  An object of this invention is to improve the durability of a pressure | voltage resistant apparatus.

  A first invention includes a cylindrical main body portion, and a lid portion having an annular wall portion, the main body portion and an end portion of the wall portion being joined together to close the opening of the main body portion, An annular groove extending in the circumferential direction is formed on at least one inner peripheral surface of the wall, and the inner diameter of the groove is larger than the inner diameters of the main body and the end of the wall.

  In the first invention, the annular groove is formed on at least one of the inner peripheral surface of the main body and the wall, and the inner diameter of the annular groove is larger than the inner diameter of the end of the main body and the wall. Therefore, the axial force acting on the main body portion and the lid portion is difficult to be transmitted to the inner periphery of the end portion of the main body portion and the inner periphery of the end portion of the wall portion. Even if protrusions are formed in the vicinity of the inner periphery of the end of the main body part and in the vicinity of the inner periphery of the end of the wall part by the joint part, stress concentration generated at the base of the protrusion can be alleviated and the pressure-resistant device is damaged. Can be prevented.

  The second invention is characterized in that the groove is formed on the inner peripheral surface of the wall.

  In the second invention, since the groove portion is formed on the inner peripheral surface of the wall portion, the axial force acting on the lid portion due to the pressure of the fluid in the pressure-resistant device is not easily transmitted to the inner periphery of the end portion of the wall portion. Even if the protrusion is formed in the vicinity of the inner periphery of the end portion of the wall portion by the joint portion, the stress concentration generated at the base of the protrusion can be more reliably alleviated and damage to the pressure-resistant device can be prevented. Therefore, the durability of the pressure resistant device can be improved.

  The third invention is characterized in that the groove portion is formed on both the inner peripheral surface of the main body portion and the inner peripheral surface of the wall portion.

  In the third invention, since the groove is formed on both the inner peripheral surface of the main body and the inner peripheral surface of the wall, the axial force acting on the main body and the lid is applied to the end of the main body. It is difficult to be transmitted by the inner periphery and the inner periphery of the end of the wall. Even if a protrusion is formed in the vicinity of the inner periphery of the end of the main body and in the vicinity of the inner periphery of the end of the wall by the joint, stress concentration generated at the base of the protrusion can be more reliably mitigated, Damage to the equipment can be prevented. Therefore, the durability of the pressure resistant device can be improved.

  4th invention is arrange | positioned along the internal peripheral surface of a main-body part and a wall part, and is further provided with the positioning part which determines the relative position of a main-body part and a wall part, It is characterized by the above-mentioned.

  In the fourth invention, since the relative position between the main body and the wall is determined by the positioning portion, the main body and the wall are not easily displaced in the radial direction at the time of joining. Therefore, it is possible to prevent an unintended step portion from being formed between the main body portion and the wall portion, and it is possible to improve the durability of the pressure resistant device.

  According to a fifth aspect of the invention, one of the main body and the wall has a positioning portion that is disposed along the other inner peripheral surface and determines a relative position between the main body and the wall.

  In the fifth aspect of the invention, since the relative position between the main body and the wall is determined by the positioning portion, the main body and the wall are less likely to be displaced in the radial direction at the time of joining. It is possible to prevent an unintended stepped portion from being formed between the main body portion and the wall portion. A positioning portion is formed on one of the main body portion and the wall portion. It is not necessary to match the position of one of the main body part and the wall part with the positioning part at the time of joining, and the main body part and the wall part can be easily joined. Therefore, it is possible to easily manufacture a pressure resistant device capable of improving durability.

  In a sixth aspect of the present invention, the groove is formed outside the region facing the positioning portion on the inner peripheral surfaces of the main body and the wall.

  In the sixth aspect of the invention, since the groove is formed outside the region of the inner peripheral surface of the main body and the wall facing the positioning portion, the positioning portion is formed on the inner peripheral surface of the main body and the wall in a wider range. The main body portion and the wall portion are less likely to be displaced in the radial direction at the time of joining and joining. Therefore, it is possible to more reliably prevent an unintended step portion from being formed between the main body portion and the wall portion, and to improve the durability of the pressure-resistant device.

  A seventh invention relates to a fluid pressure cylinder that expands and contracts when a working fluid is supplied to and discharged from the cylinder, and the cylinder is the pressure-resistant device described above.

  In the seventh invention, since the cylinder is the pressure-resistant device described above, the cylinder has high durability. Therefore, the durability of the fluid pressure cylinder can be improved.

  According to the present invention, durability of a pressure-resistant device can be improved.

It is a fragmentary sectional view of a hydraulic cylinder provided with a cylinder concerning a 1st embodiment of the present invention. It is an enlarged view of the A section in FIG. It is a figure which shows the flow (force line) of the force transmitted to a cylinder tube from a cylinder bottom, when a cylinder receives a tensile load, and shows corresponding to FIG. It is an expanded sectional view of the cylinder which concerns on the modification of 1st Embodiment of this invention. It is an expanded sectional view of the cylinder which concerns on another modification of 1st Embodiment of this invention. It is an expanded sectional view of the cylinder which concerns on another modification of 1st Embodiment of this invention. It is an expanded sectional view of the cylinder which concerns on another modification of 1st Embodiment of this invention. It is an expanded sectional view of the cylinder concerning a 2nd embodiment of the present invention. It is an expanded sectional view of a cylinder concerning a modification of a 2nd embodiment of the present invention. It is an expanded sectional view of a cylinder concerning another modification of a 2nd embodiment of the present invention. It is an expanded sectional view of a cylinder concerning another modification of a 2nd embodiment of the present invention. It is an expanded sectional view of the cylinder concerning a 2nd embodiment of the present invention. It is an expanded sectional view of a cylinder concerning a modification of a 2nd embodiment of the present invention.

  Hereinafter, a pressure-resistant device according to an embodiment of the present invention will be described with reference to the drawings. The pressure resistant device stores fluid, and the pressure of the fluid acts on the pressure resistant device from the inside. Hereinafter, a case where the pressure-resistant device is a cylinder 100, 101, 102, 103, 104, 200, 201, 202, 203, 300, 301 used in the hydraulic cylinder (fluid pressure cylinder) 1 will be described.

<First Embodiment>
First, cylinders 100, 101, 102, 103, 104 and a hydraulic cylinder 1 according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the hydraulic cylinder 1 includes a hollow cylinder 100, a piston rod 20 inserted into the cylinder 100, and slides along the inner peripheral surface of the cylinder 100 provided at the end of the piston rod 20. And a piston 30 that performs.

  The interior of the cylinder 100 is partitioned into a rod side chamber 4 and an anti-rod side chamber 5 by a piston 30. The rod side chamber 4 and the anti-rod side chamber 5 are filled with working oil as a working fluid.

  The hydraulic cylinder 1 is extended by supplying hydraulic oil to the anti-rod side chamber 5 and discharging the hydraulic oil in the rod side chamber 4. The hydraulic cylinder 1 is contracted by supplying hydraulic oil to the rod side chamber 4 and discharging the hydraulic oil in the non-rod side chamber 5. When the hydraulic oil is supplied to and discharged from the rod side chamber 4 and the non-rod side chamber 5, the pressure of the hydraulic oil acts on the cylinder 100.

  The cylinder 100 includes a cylinder tube (cylindrical main body portion) 110 and a cylinder bottom (lid portion) 120 that closes one opening of the cylinder tube 110. The piston rod 20 extends from the cylinder 100 through the other opening of the cylinder tube 110. The other opening of the cylinder tube 110 is closed by a cylinder head 50 that slidably supports the piston rod 20.

  Hereinafter, a direction along the central axis of the cylinder tube 110 is referred to as an “axial direction”, and a radial direction centered on the central axis of the cylinder tube 110 is referred to as a “radial direction” along the central axis of the cylinder tube 110. The direction is referred to as “circumferential direction”.

  FIG. 2 is an enlarged view of a portion A in FIG. As shown in FIG. 2, the cylinder bottom 120 includes a bottom main body 121 that covers the opening of the cylinder tube 110, and an annular wall portion 122 that extends from the bottom main body 121 in the axial direction. The end surface 121a of the bottom main body 121 faces the non-rod side chamber 5 (see FIG. 1). The bottom body 121 is provided with an attachment portion 123 (see FIG. 1) for attaching the hydraulic cylinder 1 to another device.

  An inner diameter D1 of the front end portion (end portion) 122a of the wall portion 122 is substantially equal to an inner diameter D2 of the open end portion (end portion) 110a of the cylinder tube 110. The front end portion 122a of the wall portion 122 is joined to the open end portion 110a of the cylinder tube 110 by welding. For the welding of the cylinder tube 110 and the wall portion 122, any method such as arc welding including plasma welding and TIG welding, gas welding, laser welding, electron beam welding, resistance welding, and friction welding can be used.

  The broken lines in FIG. 2 indicate the shapes of the cylinder tube 110 and the cylinder bottom 120 before welding. The joint part 130 is formed by welding the opening end part 110a of the cylinder tube 110 and the front end part 122a of the wall part 122. The cylinder tube 110 and the cylinder bottom 120 are integrated via the joint 130 by welding the cylinder tube 110 and the wall 122.

  The joint portion 130 may protrude from the inner peripheral surface 110b of the cylinder tube 110 and the inner peripheral surface 122b of the wall portion 122. FIG. 2 shows a state in which a part of the joint portion 130 protrudes from the inner peripheral surface 110b of the cylinder tube 110 and the inner peripheral surface 122b of the wall portion 122, that is, a state in which the protrusion 131 is formed. The bases 110 c and 122 c of the protrusion 131 are formed in the vicinity of the inner periphery of the opening end portion 110 a of the cylinder tube 110 and in the vicinity of the inner periphery of the tip end portion 122 a of the wall portion 122.

  An annular groove 124 extending in the circumferential direction is formed on the inner peripheral surface 122b of the wall 122. The maximum inner diameter D3 (hereinafter referred to as “the inner diameter D3 of the groove portion 124”) in the groove portion 124 of the wall portion 122 is larger than the inner diameter D1 of the tip end portion 122a of the wall portion 122 and the inner diameter D2 of the opening end portion 110a of the cylinder tube 110. large.

  In the cylinder 100, the groove portion 124 is formed on the entire circumference in the circumferential direction. The groove part 124 may be formed in a part in the circumferential direction.

  The cross section of the groove 124 is formed in an arcuate shape. The cross section of the groove portion 124 may have a shape other than an arc shape, for example, a triangular shape, a quadrangular shape, or the like. The cross section of the groove 124 is preferably arcuate, and in this case, stress concentration in the groove 124 can be reduced.

  FIG. 3 is a diagram illustrating a flow of force (force lines) transmitted from the cylinder bottom 120 to the cylinder tube 110 when the cylinder 100 receives a tensile load as an axial force, and corresponds to FIG. In FIG. 3, the flow of force is indicated by a broken line, and hatched lines indicating the cross sections of the cylinder tube 110, the cylinder bottom 120, and the joint 130 are omitted. The tensile load acts on the cylinder 100 by, for example, the pressure of the hydraulic oil in the cylinder 100 and the load connected to the hydraulic cylinder 1.

  In the cylinder 100, an annular groove portion 124 is formed on the inner peripheral surface 122 b of the wall portion 122. Therefore, when the cylinder 100 receives an axial force, the force acting on the cylinder bottom 120 is transmitted to the cylinder tube 110 mainly through a portion of the wall portion 122 that is positioned radially outward from the bottom surface of the groove portion 124. .

  Since the inner diameter D3 of the groove portion 124 is larger than the inner diameter D1 of the distal end portion 122a of the wall portion 122, it is difficult for force to be transmitted to the inner periphery of the distal end portion 122a of the wall portion 122. Stress concentration generated at the root 122c of the protrusion 131 can be alleviated, and damage to the joint 130 and the cylinder bottom 120 can be prevented. Therefore, the durability of the cylinder 100 can be improved.

  Further, since the inner diameter D3 of the groove portion 124 is larger than the inner diameter D2 of the opening end portion 110a of the cylinder tube 110, it is difficult for force to be transmitted to the inner periphery of the opening end portion 110a of the cylinder tube 110. Stress concentration generated at the base 110c of the protrusion 131 can be alleviated, and damage to the joint 130 and the cylinder tube 110 can be prevented. Therefore, the durability of the cylinder 100 can be improved.

  On the bottom main body 121 of the cylinder bottom 120, the pressure of the hydraulic oil in the non-rod side chamber 5 (see FIG. 1) acts in the axial direction. If the groove portion 124 is not formed on the inner peripheral surface 122b of the wall portion 122, a larger force acts on the inner periphery of the tip end portion 122a of the wall portion 122 than the inner periphery of the opening end portion 110a of the cylinder tube 110. To do. Stress tends to concentrate on the root 110c and the root 122c, and the cylinder bottom 120 is easily damaged.

  In the cylinder 100, the groove portion 124 is formed on the inner peripheral surface 122 b of the wall portion 122, while the groove portion is not formed on the inner peripheral surface 110 b of the cylinder tube 110. Compared with the inner periphery of the opening end portion 110 a of the cylinder tube 110, the force is more difficult to be transmitted to the inner periphery of the tip end portion 122 a of the wall portion 122. The stress concentration generated at the root 122c of the protrusion 131 can be more reliably mitigated, and the cylinder bottom 120 can be prevented from being damaged.

  The groove portion 124 formed on the inner peripheral surface 122b of the wall portion 122 reduces the rigidity of the wall portion 122, and the wall portion 122 is easily elastically deformed. Since the wall 122 is easily deformed in accordance with the deformation of the cylinder tube 110, stress concentration generated at the roots 110c and 122c of the protrusion 131 can be reduced.

  The groove portion 124 is formed across the inner peripheral surface 122 b of the wall portion 122 and the end surface 121 a of the bottom main body 121. In other words, the groove portion 124 forms a curved surface between the inner peripheral surface 122 b of the wall portion 122 and the end surface 121 a of the bottom main body 121. Compared with the case where a curved surface is formed between the inner peripheral surface 122b of the wall portion 122 and the surface of the bottom main body 121 without depending on the groove portion 124, the radius of curvature of the groove portion 124 can be increased. Stress concentration can be relaxed.

  FIG. 4 is an enlarged cross-sectional view showing a cylinder 101 according to a modification of the first embodiment. In the cylinder 101, a groove portion 114 extending in the circumferential direction is formed on the inner peripheral surface 110b of the cylinder tube 110. The groove 114 is formed on the entire circumference in the circumferential direction. The maximum inner diameter D4 (hereinafter referred to as “the inner diameter D4 of the groove 114”) in the groove 114 of the cylinder tube 110 is larger than the inner diameter D1 of the tip 122a of the wall 122 and the inner diameter D2 of the opening end 110a of the cylinder tube 110. large.

  The groove 114 is not limited to the form formed on the entire circumference, and may be formed on a part in the circumferential direction.

  The cross section of the groove 144 is formed in an arcuate shape. The cross section of the groove 114 may have a shape other than an arc shape, for example, a triangle, a quadrangle, or the like. The cross section of the groove 114 is preferably arcuate, and in this case, stress concentration in the groove 114 can be reduced.

  Also in the cylinder 101, similarly to the cylinder 100, it is difficult for force to be transmitted to the inner periphery of the opening end portion 110 a of the cylinder tube 110 and the inner periphery of the tip end portion 122 a of the wall portion 122. Stress concentration generated at the root 110c and the root 122c of the protrusion 131 can be alleviated, and damage to the cylinder tube 110, the cylinder bottom 120, and the joint 130 can be prevented. Therefore, the durability of the cylinder 101 can be improved.

  FIG. 5 is an enlarged cross-sectional view showing a cylinder 102 according to a modification of the first embodiment. In the cylinder 102, a groove portion 114 is formed on the inner peripheral surface 110 b of the cylinder tube 110, and a groove portion 124 is formed on the inner peripheral surface 122 b of the wall portion 122.

  Also in the cylinder 102, as in the cylinders 100 and 101, it is difficult for force to be transmitted to the inner periphery of the opening end portion 110 a of the cylinder tube 110 and the inner periphery of the tip portion 122 a of the wall portion 122. Stress concentration generated at the root 110c and the root 122c of the protrusion 131 can be alleviated, and damage to the cylinder tube 110, the cylinder bottom 120, and the joint 130 can be prevented. Therefore, the durability of the cylinder 102 can be improved.

  Also in the cylinder 102, as in the cylinder 100, the rigidity of the wall portion 122 is lowered by the groove portion 124 formed in the inner peripheral surface 122 b of the wall portion 122. The wall 122 is easily deformed according to the deformation of the cylinder tube 110, and the stress concentration generated at the roots 110c and 122c of the protrusion 131 can be reduced.

  The groove portion 124 is formed across the inner peripheral surface 122 b of the wall portion 122 and the end surface 121 a of the bottom main body 121. Similar to the cylinder 100, the radius of curvature of the groove 124 can be increased, and the stress concentration in the groove 124 can be reduced.

  FIG. 6 is a cross-sectional view of a cylinder 103 according to a modification of the first embodiment. In the cylinder 103, the cylinder tube 110 includes a tube main body 111 that houses the piston 30 (see FIG. 1), and an annular portion 112 that extends annularly from one end of the tube main body 111 in the axial direction. The tip of the annular portion 112 is an opening end portion 110 a of the cylinder tube 110, and the opening of the cylinder tube 110 is formed by the tip of the annular portion 112.

  The inner diameter of the tube main body 111 is substantially equal to the outer diameter of the piston 30, and the piston 30 can slide along the inner peripheral surface of the tube main body 111. The inner diameter of the tube body 111 corresponds to a so-called cylinder diameter. The inner diameter of the annular portion 112 is larger than the inner diameter of the tube main body 111.

  The inner diameter of the wall portion 122 of the cylinder bottom 120 is larger than the inner diameter of the tube main body 111. The inner diameter D1 of the front end portion 122a of the wall portion 122 is substantially equal to the inner diameter of the opening end portion 110a of the annular portion 112 (the inner diameter D2 of the opening end portion 110a of the cylinder tube 110). The front end portion 122a of the wall portion 122 and the open end portion 110a of the annular portion 112 are joined by welding.

  The annular groove 114 is formed on the inner peripheral surface 110 b of the annular part 112. An inner diameter D4 of the groove portion 114 of the annular portion 112 is larger than an inner diameter D1 of the front end portion 122a of the wall portion 122 and an inner diameter D2 of the opening end portion 110a of the annular portion 112.

  The annular groove portion 124 is formed on the inner peripheral surface 122 b of the wall portion 122 of the cylinder bottom 120. The inner diameter D3 of the groove portion 124 of the wall portion 122 is larger than the inner diameter D1 of the front end portion 122a of the wall portion 122 and the inner diameter D2 of the opening end portion 110a of the annular portion 112.

  Also in the cylinder 103, since the inner diameter D4 of the groove portion 114 and the inner diameter D3 of the groove portion 124 are larger than the inner diameter D1 of the distal end portion 122a of the wall portion 122 and the inner diameter D2 of the opening end portion 110a of the annular portion 112. It is difficult for force to be transmitted to the inner periphery of the portion 110 a and the inner periphery of the tip portion 122 a of the wall portion 122. Stress concentration generated at the root 110c and the root 122c of the protrusion 131 can be alleviated, and damage to the cylinder tube 110, the cylinder bottom 120, and the joint 130 can be prevented. Therefore, the durability of the cylinder 103 can be improved.

  Further, similar to the cylinder 100, the rigidity of the wall portion 122 is reduced by the groove portion 124 formed on the inner peripheral surface 122b of the wall portion 122. Therefore, the stress concentration generated at the roots 110c and 122c of the protrusion 131 can be reduced. it can.

  The cylinder 103 is not limited to the form in which the groove 114 and the groove 124 are formed on both the inner peripheral surface 110 b of the annular portion 112 and the inner peripheral surface 122 b of the wall portion 122. The groove 114 may be formed only on the inner peripheral surface 110 b of the annular portion 122, and the groove 124 may not be formed on the inner peripheral surface 122 b of the wall portion 122. The groove portion 124 may be formed only on the inner peripheral surface 122b of the wall portion 122, and the groove portion 114 may not be formed on the inner peripheral surface 110b of the annular portion 122.

  FIG. 7 is a cross-sectional view showing a cylinder 104 according to a modification of the first embodiment. In the cylinder 104, a part of the inner peripheral surface 110b of the cylinder tube 110 and a part of the inner peripheral surface 122b of the wall portion 122 are deformed so as to protrude radially inward. That is, the protrusion 131 is formed by a part of the cylinder tube 110 and a part of the wall part 122.

  Also in the cylinder 104, a groove portion 124 is formed on the inner peripheral surface 122 b of the wall portion 122, and a groove portion 114 is formed on the inner peripheral surface 110 b of the cylinder tube 110. The stress concentration generated at the root 110c and the root 122c of the protrusion 131 can be relaxed, and the cylinder tube 110 and the cylinder bottom 120 can be prevented from being damaged. Therefore, the durability of the cylinder 104 can be improved.

  Also in the cylinder 104, as in the cylinder 100, the rigidity of the wall portion 122 is reduced by the groove portion 124 formed in the inner peripheral surface 122 b of the wall portion 122, so that stress concentration generated at the roots 110 c and 122 c of the protrusion 131 is reduced. can do. Since the groove portion 124 is formed across the inner peripheral surface 122b of the wall portion 122 and the end surface 121a of the bottom main body 121, similarly to the cylinder 100, the radius of curvature of the groove portion 124 can be increased, and the stress concentration of the groove portion 124 can be increased. Can be relaxed.

  The cylinder 104 is not limited to the form in which the groove portion 114 and the groove portion 124 are formed on both the inner peripheral surface 110b of the cylinder tube 110 and the inner peripheral surface 122b of the wall portion 122. The groove 114 may be formed only on the inner peripheral surface 110 b of the cylinder tube 110, and the groove 124 may not be formed on the inner peripheral surface 122 b of the wall portion 122. The groove 124 may be formed only on the inner peripheral surface 122b of the wall 122, and the groove 114 may not be formed on the inner peripheral surface 110b of the cylinder tube 110.

Second Embodiment
Next, cylinders 200, 201, 202, and 203 according to a second embodiment of the present invention will be described with reference to FIGS. The same components as those of the cylinder 100 according to the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Further, the hydraulic cylinder to which the cylinders 200, 201, 202, and 203 can be applied is substantially the same as the hydraulic cylinder 1 shown in FIG.

  As shown in FIG. 8, the cylinder 200 includes a cylinder tube 210, a cylinder bottom 220, and an annular positioning portion 240 that determines a relative position between the cylinder tube 210 and the cylinder bottom 220. The cylinder bottom 220 has a bottom main body 221 and an annular wall portion 222. The annular positioning portion 240 is disposed along the inner peripheral surface 210 b of the cylinder tube 210 and the inner peripheral surface 222 b of the wall portion 222.

  The positioning portion 240 is formed separately from the cylinder tube 210 and the wall portion 222 before the cylinder tube 210 and the wall portion 222 are joined. When joining the cylinder tube 210 and the wall portion 222, first, the cylinder tube 210 and the wall portion 222 are fitted to the outer peripheral surface 240 a of the positioning portion 240, and the opening end portion 210 a of the cylinder tube 210 and the wall portion 222 are The tip portions 222a are abutted against each other. Next, heat is applied to the cylinder tube 210 and the wall portion 222 to join the opening end portion 210a and the tip end portion 222a. At this time, the positioning part 240 is joined to the joining part 230.

  Since the relative position between the cylinder tube 210 and the wall portion 222 is determined by the positioning portion 240 when the cylinder tube 210 and the wall portion 222 are welded, the displacement between the cylinder tube 210 and the wall portion 222 can be prevented. The cylinder tube 210 and the wall 222 can be welded in a state where the axis of the cylinder tube 210 and the axis of the wall 222 are aligned. For the welding of the cylinder tube 210 and the wall portion 222, any method such as arc welding including plasma welding and TIG welding, gas welding, laser welding, electron beam welding, resistance welding, and friction welding can be used.

  A part of the outer peripheral surface 240 a of the positioning portion 240 is bonded to the bonding portion 230, and the other portion of the outer peripheral surface 240 a is not bonded to the bonding portion 230. That is, the other part of the outer peripheral surface 240 a of the positioning part 240 is close to the cylinder tube 210 and the wall part 222 without passing through the joint part 230.

  The entire outer peripheral surface 240 a of the positioning part 240 may be joined to the joint part 230.

  Since the opening end portion 210a of the cylinder tube 210 and the tip end portion 222a of the wall portion 222 are joined via the joint portion 230, and the positioning portion 240 is joined to the joint portion 230, the positioning portion 240 is composed of the inner peripheral surface 210b and the inner end surface 210b. This corresponds to a protrusion protruding from the peripheral surface 222b. In other words, the positioning portion 240 corresponds to the protrusion 131 (see FIG. 2) in the cylinder 100. Bases (bases) 210 c and 222 c of the positioning portion 240 are formed in the vicinity of the inner periphery of the opening end portion 210 a of the cylinder tube 210 and in the vicinity of the inner periphery of the tip end portion 222 a of the wall portion 222.

  An annular groove 224 is formed on the inner peripheral surface 222 b of the wall 222. Therefore, when the cylinder 200 receives an axial force, the force acting on the cylinder bottom 220 is transmitted to the cylinder tube 210 mainly through a portion of the wall portion 222 that is positioned radially outward from the bottom surface of the groove portion 224. .

  The groove portion 124 may be formed on the entire circumference in the circumferential direction, or may be formed on a part in the circumferential direction.

  The inner diameter D3 of the groove portion 224 of the wall portion 222 is larger than the inner diameter D1 of the front end portion 222a of the wall portion 222. It is difficult for force to be transmitted to the inner periphery of the front end portion 222a of the wall portion 222, stress concentration generated at the root 222c can be reduced, and damage to the cylinder bottom 220 and the joint portion 230 can be prevented. Therefore, the durability of the cylinder 200 can be improved.

  Further, the inner diameter D3 of the groove 224 is larger than the inner diameter D2 of the open end 210a of the cylinder tube 210. A force is hardly transmitted to the inner periphery of the opening end portion 210a of the cylinder tube 210, stress concentration generated at the root 210c can be relaxed, and damage to the cylinder tube 210 and the joint portion 230 can be prevented. Therefore, the durability of the cylinder 200 can be improved.

  The groove portion 224 is formed outside the region facing the positioning portion 240 in the inner peripheral surface 222 b of the wall portion 222. Since the positioning portion 240 is in contact with the inner peripheral surface 210b of the cylinder tube 210 and the inner peripheral surface 222b of the wall portion 222 in a wider range, the cylinder tube 210 and the wall portion 222 are not easily displaced in the radial direction at the time of joining. Therefore, an unintended step portion can be prevented from being formed between the cylinder tube 210 and the wall portion 222, and the durability of the cylinder 200 can be improved.

  Also in the cylinder 200, as in the cylinder 100 (see FIG. 2), the groove portion 224 formed on the inner peripheral surface 222 b of the wall portion 222 reduces the rigidity of the wall portion 222, and the wall portion 222 is easily elastically deformed. . Since the wall portion 222 is easily deformed in accordance with the deformation of the cylinder tube 210, the stress concentration generated at the roots 210c and 222c of the joint portion 230 can be more reliably mitigated.

  The groove portion 224 is formed across the inner peripheral surface 222 b of the wall portion 222 and the end surface 221 a of the bottom main body 221. That is, the groove portion 224 forms a curved surface between the inner peripheral surface 222 b of the wall portion 222 and the end surface 221 a of the bottom main body 221. Compared to the case where a curved surface is formed between the inner peripheral surface 222b of the wall portion 222 and the surface of the bottom main body 221 irrespective of the groove portion 224, the radius of curvature of the groove portion 224 can be increased. Stress concentration can be relaxed.

  FIG. 9 is an enlarged cross-sectional view showing a cylinder 201 according to a modification of the second embodiment. In the cylinder 201, a groove portion 214 extending in the circumferential direction is formed on the inner peripheral surface 210b of the cylinder tube 210. The groove 2144 is formed on the entire circumference in the circumferential direction. The inner diameter D4 of the groove portion 214 of the cylinder tube 210 is larger than the inner diameter D1 of the tip end portion 222a of the wall portion 222 and the inner diameter D2 of the opening end portion 210a of the cylinder tube 210.

  The groove 214 is not limited to the form formed on the entire circumference, and may be formed on a part in the circumferential direction.

  Also in the cylinder 201, similarly to the cylinder 200, it is difficult for force to be transmitted to the inner periphery of the opening end portion 210 a of the cylinder tube 210 and the inner periphery of the tip end portion 222 a of the wall portion 222. Stress concentration generated at the root 210c and the root 222c can be alleviated, and damage to the cylinder tube 210, the cylinder bottom 220, and the joint portion 230 can be prevented. Therefore, the durability of the cylinder 201 can be improved.

  The groove portion 214 is formed outside the region facing the positioning portion 240 in the inner peripheral surface 210b of the cylinder tube 210. Therefore, similarly to the cylinder 200, the cylinder tube 210 and the wall portion 222 are not easily displaced in the radial direction at the time of joining, and the durability of the cylinder 201 can be improved.

  FIG. 10 is an enlarged cross-sectional view showing a cylinder 202 according to a modification of the second embodiment. In the cylinder 202, a groove portion 214 is formed on the inner peripheral surface 210 b of the cylinder tube 210, and a groove portion 224 is formed on the inner peripheral surface 222 b of the wall portion 222. A part of the groove part 214 is formed in a region of the inner peripheral surface 210b of the cylinder tube 210 facing the positioning part 240, and a part of the groove part 224 is formed on the positioning part 240 of the inner peripheral surface 222b of the wall part 222. It is formed in the opposing region.

  FIG. 11 is an enlarged cross-sectional view showing a cylinder 203 according to a modification of the second embodiment. In the cylinder 203, the entire groove 214 is formed in a region of the inner peripheral surface 210 b of the cylinder tube 210 that faces the positioning portion 240. Further, the entire groove portion 224 is formed in a region of the inner peripheral surface 222 b of the wall portion 222 that faces the positioning portion 240.

  Also in the cylinder 202 (see FIG. 10) and the cylinder 203 (see FIG. 11), similarly to the cylinder 200 and the cylinder 201, on the inner periphery of the opening end portion 210a of the cylinder tube 210 and the inner periphery of the tip end portion 222a of the wall portion 222. Power is difficult to convey. Stress concentration generated at the root 210c and the root 222c can be alleviated, and damage to the cylinder tube 210, the cylinder bottom 220, and the joint portion 230 can be prevented. Therefore, durability of the cylinder 202 and the cylinder 203 can be improved.

  The cylinder 202 and the cylinder 203 are not limited to the form in which the groove 214 and the groove 224 are formed on both the inner peripheral surface 210b of the cylinder tube 210 and the inner peripheral surface 222b of the wall 222. The groove 214 may be formed only on the inner peripheral surface 210b of the cylinder tube 210, and the groove 224 may not be formed on the inner peripheral surface 222b of the wall 222. The groove portion 224 may be formed only on the inner peripheral surface 222b of the wall portion 222, and the groove portion 114 may not be formed on the inner peripheral surface 210b of the cylinder tube 210.

  Also in the cylinder 202 and the cylinder 203, as in the cylinder 200, the rigidity of the wall portion 222 is reduced by the groove portion 124 formed in the inner peripheral surface 222 b of the wall portion 222. The wall 222 is easily deformed according to the deformation of the cylinder tube 210, and the stress concentration generated at the roots 210c and 222c can be reduced.

  In the cylinder 202, the groove portion 224 is formed across the inner peripheral surface 222 b of the wall portion 222 and the end surface 221 a of the bottom main body 221. Similar to the cylinder 200, the radius of curvature of the groove 224 can be increased, and the stress concentration in the groove 224 can be reduced.

<Third Embodiment>
Next, cylinders 300 and 301 according to a third embodiment of the present invention will be described with reference to FIGS. The same components as those of the cylinders 100 and 200 according to the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted. The hydraulic cylinder to which the cylinders 300 and 301 can be applied is substantially the same as the hydraulic cylinder 1 shown in FIG.

  As shown in FIG. 12, the cylinder 300 includes a cylinder tube 310 and a cylinder bottom 320. The cylinder bottom 320 has a bottom main body 321 and an annular wall portion 322. The wall portion 322 includes a positioning portion 340 that determines a relative position between the cylinder tube 310 and the wall portion 322. The positioning portion 340 is disposed along the inner peripheral surface 310b of the cylinder tube 310.

  The positioning portion 340 is formed separately from the cylinder tube 310 before the cylinder tube 310 and the wall portion 322 are joined. When joining the cylinder tube 310 and the wall portion 322, first, the cylinder tube 310 is fitted to the outer peripheral surface 340a of the positioning portion 340, and the opening end portion 310a of the cylinder tube 310 and the tip end portion 322a of the wall portion 322 are connected to each other. Butt each other. Next, heat is applied to the cylinder tube 310 and the wall portion 322 to join the opening end portion 310a and the tip end portion 322a. At this time, the positioning part 340 is joined to the joining part 330.

  Since the relative position between the cylinder tube 310 and the wall portion 322 is determined by the positioning portion 340 when the cylinder tube 310 and the wall portion 322 are joined, the displacement between the cylinder tube 310 and the wall portion 322 can be prevented. For joining the cylinder tube 310 and the wall portion 322, any method such as arc welding including plasma welding and TIG welding, gas welding, laser welding, electron beam welding, resistance welding, and friction welding can be used.

  Since the positioning part 340 is formed in the wall part 322, it is not necessary to match | combine the position of the wall part 322 and the positioning part 340 at the time of joining. Therefore, the cylinder tube 310 and the wall 222 can be easily joined, and the cylinder 300 capable of improving durability can be easily manufactured.

  A part of the outer peripheral surface 340 a of the positioning unit 340 is joined to the joint 330, and the other part of the outer peripheral surface 340 a is not joined to the joint 330. That is, the other part of the outer peripheral surface 340 a of the positioning part 340 is close to the cylinder tube 310 without the joint part 330 interposed therebetween.

  The entire outer peripheral surface 340 a of the positioning part 340 may be joined to the joining part 330.

  Since the opening end portion 310a of the cylinder tube 310 and the tip end portion 322a of the wall portion 322 are joined via the joining portion 330 and the positioning portion 340 is joined to the joining portion 330, the positioning portion 340 protrudes from the inner peripheral surface 310b. It corresponds to the protruding part. In other words, the positioning portion 340 corresponds to the protrusion 131 (see FIG. 2) in the cylinder 100. A root (base) 310 c of the positioning portion 340 is formed on the inner periphery of the opening end portion 310 a of the cylinder tube 310.

  An annular groove 324 is formed on the inner peripheral surface 322 b of the wall 322. Therefore, when the cylinder 300 receives an axial force, the force acting on the cylinder bottom 320 is transmitted to the cylinder tube 310 mainly through a portion of the wall portion 322 that is positioned radially outward from the bottom surface of the groove portion 324. .

  The groove portion 324 may be formed on the entire circumference in the circumferential direction, or may be formed on a part in the circumferential direction.

  The inner diameter D3 of the groove 324 of the wall 322 is larger than the inner diameter D2 of the open end 310a of the cylinder tube 310. A force is hardly transmitted to the inner periphery of the opening end portion 310a of the cylinder tube 310, stress concentration generated at the root 310c can be reduced, and damage to the cylinder tube 310 and the joint portion 330 can be prevented. Therefore, the durability of the cylinder 300 can be improved.

  FIG. 13 is an enlarged cross-sectional view showing a cylinder 301 according to a modification of the third embodiment. In the cylinder 301, a groove portion 314 is formed on the inner peripheral surface 310 b of the cylinder tube 310, and a groove portion 324 is formed on the inner peripheral surface 322 b of the wall portion 322. The groove portion 313 and the groove portion 324 may be formed on the entire circumference in the circumferential direction, or may be formed on a part in the circumferential direction.

  An inner diameter D4 of the groove 314 of the cylinder tube 310 is larger than an inner diameter D2 of the open end 310a of the cylinder tube 310. Force is less likely to be transmitted to the inner periphery of the opening end portion 310a of the cylinder tube 310, stress concentration generated at the root 310c of the joint portion 330 can be more reliably mitigated, and damage to the cylinder tube 310 and the joint portion 330 can be prevented. can do. Therefore, the durability of the cylinder 300 can be improved.

  The groove portion 314 is formed outside the region of the inner peripheral surface 310b of the cylinder tube 310 that faces the positioning portion 340. The positioning portion 340 is in contact with the inner peripheral surface 310b of the cylinder tube 310 in a wider range, and the cylinder tube 310 is not easily displaced in the radial direction with respect to the wall portion 322 at the time of joining. Therefore, an unintended stepped portion can be prevented from being formed between the cylinder tube 310 and the wall portion 322, and the durability of the cylinder 301 can be improved.

  The cylinder 300 is not limited to the form in which the annular groove 324 is formed only on the inner peripheral surface 322b of the wall 322 (see FIG. 12). Further, the cylinder 300 is not limited to the form (FIG. 13) in which the groove portion 314 and the groove portion 324 are formed on both the inner peripheral surface 310 b of the cylinder tube 310 and the inner peripheral surface 322 b of the wall portion 322. The groove 314 may be formed only on the inner peripheral surface 310 b of the cylinder tube 310, and the groove 324 may not be formed on the inner peripheral surface 322 b of the wall 322.

  In the cylinder 301, the groove portion 314 is formed outside the region of the inner peripheral surface 310 b of the cylinder tube 310 that faces the positioning portion 340. At least a part of the groove portion 314 may be formed in a region of the inner peripheral surface 310 b of the cylinder tube 310 that faces the positioning portion 340.

  Also in the cylinder 300 and the cylinder 301, as in the cylinder 100 (see FIG. 2), the rigidity of the wall portion 322 is reduced by the groove portion 324 formed in the inner peripheral surface 322b of the wall portion 322, and the wall portion 322 is elastically deformed. It becomes easy to do. Since the wall portion 322 is easily deformed in accordance with the deformation of the cylinder tube 310, the stress concentration generated at the root 310c of the joint portion 330 can be reduced.

  The groove portion 324 is formed across the inner peripheral surface 322 b of the wall portion 322 and the end surface 321 a of the bottom main body 321. That is, the groove portion 324 forms a curved surface between the inner peripheral surface 322 b of the wall portion 322 and the end surface 321 a of the bottom main body 321. Compared with the case where a curved surface is formed between the inner peripheral surface 322b of the wall portion 322 and the surface of the bottom main body 321 regardless of the groove portion 324, the radius of curvature of the groove portion 324 can be increased, Stress concentration can be relaxed.

  In the cylinder 300 and the cylinder 301, the wall portion 322 includes the positioning portion 340, and the positioning portion 340 is disposed along the inner periphery of the inner peripheral surface 310 b of the cylinder tube 310. The positioning portion 340 may be provided integrally with the cylinder tube 310 and disposed along the inner peripheral surface 322b of the wall portion 322.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  In this embodiment, the cylinders 100, 101, 102, 103, 104, 200, 201, 202, 203, 300, 301 have cylinder tubes 110, 210, 310 and annular walls 122, 222, 322. Cylinders in which the opening ends 110a, 210a, 310a of the cylinder tubes 110, 210, 310 are joined to the leading ends 122a, 222a, 322a of the wall portions 122, 222, 322 to close the openings of the cylinder tubes 110, 210, 310. Bottom 120, 220, 320, and extends in the circumferential direction on at least one of the inner peripheral surfaces 110b, 210b, 310b, 122b, 222b, 322b of the cylinder tubes 110, 210, 310 and the walls 122, 222, 322. Existing annular grooves 114, 214, 314, 124, 22 324, and the inner diameters D3, D4 of the grooves 114, 214, 314, 124, 224, 324 are the inner diameters D2 of the opening ends 110a, 210a, 310a of the cylinder tubes 110, 210, 310 and the wall parts 122, 222. , 322 is larger than the inner diameter D1 of the front end portions 122a, 222a, 322a.

  In this configuration, the annular grooves 114, 214, 314, 124, 224, and 324 are formed on the inner peripheral surfaces 110 b, 210 b, 310 b of the cylinder tubes 110, 210, 310 and the inner peripheral surfaces 122 b, 222 b of the walls 122, 222, 322. , 322b formed in at least one of the annular grooves 114, 214, 314, 124, 224, and 324, the inner diameters D3 and D4 of the cylinder tubes 110, 210, and 310 are the inner diameters D2 and wall portions of the opening ends 110a, 210a, and 310a. It is larger than the inner diameter D1 of the front end portions 122a, 222a, 322a of 122, 222, 322. Therefore, the axial force acting on the cylinder tubes 110, 210, 310 and the cylinder bottoms 120, 220, 320 is the inner periphery of the opening ends 110 a, 210 a, 310 a of the cylinder tubes 110, 210, 310 and the wall portions 122, It is difficult to be transmitted to the inner periphery of the front end portions 122a, 222a, 322a of 222, 322. The joints 130, 230, and 330 project near the inner periphery of the open ends 110a, 210a, and 310a of the cylinder tubes 110, 210, and 310 and near the inner periphery of the tip portions 122a, 222a, and 322a of the walls 122, 222, and 322. Even if the portion 131 is formed, the stress concentration generated at the bases 110c, 210c, 310c, 122c, and 222c of the protrusion 131 can be reduced, and the cylinders 100, 101, 102, 103, 104, 200, 201, 202, Damage to 203, 300, and 301 can be prevented. Therefore, durability of the cylinders 100, 101, 102, 103, 104, 200, 201, 202, 203, 300, 301 can be enhanced.

  In the present embodiment, the groove portions 124, 224, and 324 are formed on the inner peripheral surfaces 122b, 222b, and 322b of the wall portions 122, 222, and 322, respectively.

  In this configuration, the groove portions 124, 224, 324 are formed on the inner peripheral surfaces 122b, 222b, 322b of the wall portions 122, 222, 322, so that the cylinders 100, 102, 103, 104, 200, 202, 203, 300, The axial force acting on the cylinder bottoms 120, 220, and 320 due to the pressure of the hydraulic oil in the 301 is difficult to be transmitted to the inner periphery of the tip portions 122 a, 222 a, and 322 a of the wall portions 122, 222, and 322. Even if the protrusion 131 is formed in the vicinity of the inner periphery of the front end portions 122a, 222a, and 322a of the wall portions 122, 222, and 322 by the joint portions 130, 230, and 330, stress concentration generated at the roots 122c and 222c of the protrusion 131 is generated. It can be mitigated more reliably, and the cylinders 100, 102, 103, 104, 200, 202, 203, 300, 301 can be prevented from being damaged. Therefore, the durability of the cylinders 100, 102, 103, 104, 200, 202, 203, 300, 301 can be improved. Further, the rigidity of the cylinder bottoms 120, 220, and 320 is reduced by the grooves 124, 224, and 324 formed in the inner peripheral surfaces 122b, 222b, and 322b of the walls 122, 222, and 322, and the cylinder bottoms 120, 220, and 320 are reduced. Becomes easily elastically deformed. The stress concentration generated at the roots 110c, 122c, 210c, 222c, and 310c of the protrusion 131 can be more reliably mitigated. Furthermore, in the cylinders 100, 200, and 300, since it is not necessary to form grooves in the cylinder tubes 110, 210, and 310, the cylinder tubes 110, 210, and 310 can be easily formed.

  In the present embodiment, the grooves 114, 214, 314, 124, 224, and 324 include the inner peripheral surfaces 110 b, 210 b, 310 b of the cylinder tubes 110, 210, 310 and the inner peripheral surfaces 122 b of the walls 122, 222, 322. , 222b, and 322b.

  In this configuration, the grooves 114, 214, 314, 124, 224, and 324 are formed on the inner peripheral surfaces 110 b, 210 b, 310 b of the cylinder tubes 110, 210, 310 and the inner peripheral surfaces 122 b, 222 b, 322 b of the walls 122, 222, 322. Therefore, the axial force acting on the cylinder tubes 110, 210, 310 and the cylinder bottoms 120, 220, 320 is applied to the open ends 110a, 210a, 310a of the cylinder tubes 110, 210, 310. It is difficult to be transmitted by the inner periphery and the inner periphery of the end portions 122a, 222a, 322a of the wall portions 122, 223, 323. The joints 130, 230, and 330 project near the inner periphery of the open ends 110a, 210a, and 310a of the cylinder tubes 110, 210, and 310 and near the inner periphery of the tip portions 122a, 222a, and 322a of the walls 122, 222, and 322. Even if the portion 131 is formed, the stress concentration generated at the bases 110c, 210c, 310c, 122c, and 222c of the protrusion 131 can be more reliably mitigated, and the cylinders 102, 103, 104, 202, 203, and 301 are damaged. Can be prevented. Therefore, the durability of the cylinders 102, 103, 104, 202, 203, 301 can be improved.

  Further, in the present embodiment, it further includes a positioning portion 240 that is disposed along the inner peripheral surface 210b of the cylinder tube 210 and the inner peripheral surface 222b of the wall portion 222, and determines the relative position between the cylinder tube 210 and the wall portion 222. It is characterized by.

  In this configuration, since the relative position between the cylinder tube 210 and the wall portion 222 is determined by the positioning portion 240, the cylinder tube 210 and the wall portion 222 are not easily displaced in the radial direction at the time of joining. Therefore, an unintended stepped portion can be prevented from being formed between the cylinder tube 210 and the wall portion 222, and the durability of the cylinders 200, 201, 202, 203 can be improved.

  In the present embodiment, the wall portion 322 includes a positioning portion 340 that is disposed along the inner peripheral surface 310b of the cylinder tube 310 and determines the relative position between the cylinder tube 310 and the wall portion 322.

  In this configuration, since the relative position between the cylinder tube 310 and the wall portion 322 is determined by the positioning portion 340, the cylinder tube 310 and the wall portion 322 are not easily displaced in the radial direction at the time of joining. An unintended stepped portion can be prevented from being formed between the cylinder tube 310 and the wall portion 322. A positioning part 340 is formed on the wall part 322. It is not necessary to match the positions of the wall portion 322 and the positioning portion 340 at the time of joining, and the cylinder tube 310 and the wall portion 322 can be easily joined. Therefore, the cylinders 300 and 301 capable of improving durability can be easily manufactured.

  In the present embodiment, the groove portions 114, 214, 314, 124, 224, and 324 are the inner peripheral surfaces 110 b, 210 b, 310 b of the cylinder tubes 110, 210, 310 and the inner peripheral surfaces 122 b of the wall portions 122, 222, 322. , 222b and 322b are formed outside a region facing the positioning portions 240 and 340.

  In this configuration, the grooves 114, 214, 314, 124, 224, 324 are the inner peripheral surfaces 110 b, 210 b, 310 b of the cylinder tubes 110, 210, 310 and the inner peripheral surfaces 122 b, 222 b, 322 b of the walls 122, 222, 322. Since the positioning portions 240 and 340 are formed outside the region facing the positioning portions 240 and 340, the inner peripheral surfaces 110b, 210b, and 310b of the cylinder tubes 110, 210, and 310 and the wall portions 122, The cylinder tubes 110, 210, 310 and the wall portions 122, 222, 322 are less likely to be displaced in the radial direction when they are in contact with the inner peripheral surfaces 122 b, 222 b, 322 b of 222, 322. Therefore, it is possible to more reliably prevent unintended steps from being formed between the cylinder tubes 110, 210, 310 and the walls 122, 222, 322, and the durability of the cylinders 200, 201, 300, 301 is improved. Can be improved.

  In addition, the present embodiment relates to a hydraulic cylinder 1 that expands and contracts when hydraulic oil is supplied to and discharged from the cylinder. The cylinders are cylinders 100, 101, 102, 103, 104, 200, 201, 202, 203, 300, 301.

  In this configuration, since the cylinder is the above-described cylinder 100, 101, 102, 103, 104, 200, 201, 202, 203, 300, 301, the cylinder has high durability. Therefore, the durability of the hydraulic cylinder 1 can be improved.

  Although the embodiments of the present invention have been described above, each of the above embodiments is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiments. is not.

  In the above embodiment, the cylinder used for the hydraulic cylinder 1 has been described as the pressure-resistant device. The pressure-resistant device is not limited to this, and may be a pressure vessel such as a cylinder for storing liquid or gas.

  DESCRIPTION OF SYMBOLS 1 ... Hydraulic cylinder (fluid pressure cylinder), 100, 100, 102, 103, 104, 200, 201, 202, 203, 300, 301 ... Cylinder (pressure-resistant device), 110, 210, 220 ... Cylinder tube (cylindrical main body), 110a, 210a, 220a ... Open end (end), 110a, 210b, 220b ... Inner peripheral surface, 114, 214, 314 ... Groove, 120, 220, 320 ... cylinder bottom (lid), 122, 222, 322 ... wall, 122a, 222a, 322a ... tip (end), 122b, 222b, 322b ... inner peripheral surface , 124, 224, 324 ... groove, 130, 230, 330 ... joint, 131 ... projection, 240, 340 ... positioning part

Claims (7)

A tubular body,
An annular wall portion, the body portion and the end portion of the wall portion are joined to each other, and a lid portion that closes the opening of the body portion,
An annular groove extending in the circumferential direction is formed on the inner peripheral surface of at least one of the main body and the wall,
The pressure resistant device, wherein an inner diameter of the groove portion is larger than inner diameters of the end portions of the main body portion and the wall portion.   The pressure-resistant device according to claim 1, wherein the groove portion is formed on an inner peripheral surface of the wall portion.   The pressure-resistant device according to claim 1, wherein the groove portion is formed on both an inner peripheral surface of the main body portion and an inner peripheral surface of the wall portion.   4. The apparatus according to claim 1, further comprising a positioning portion that is disposed along an inner peripheral surface of the main body portion and the wall portion and determines a relative position between the main body portion and the wall portion. Pressure-resistant equipment as described in   One of the said main-body part and the said wall part has a positioning part which is arrange | positioned along the other internal peripheral surface and determines the relative position of the said main-body part and the said wall part, The any one of Claim 1 to 3 characterized by the above-mentioned. 2. The pressure resistant device according to item 1.   6. The pressure-resistant device according to claim 4, wherein the groove is formed outside an area of the inner peripheral surface of the main body and the wall that faces the positioning portion. A fluid pressure cylinder that expands and contracts when working fluid is supplied to and discharged from the cylinder,
The fluid pressure cylinder according to any one of claims 1 to 6, wherein the cylinder is a pressure resistant device according to any one of claims 1 to 6.

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