WO2022172846A1 - Hydraulic cylinder - Google Patents

Hydraulic cylinder Download PDF

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Publication number
WO2022172846A1
WO2022172846A1 PCT/JP2022/004181 JP2022004181W WO2022172846A1 WO 2022172846 A1 WO2022172846 A1 WO 2022172846A1 JP 2022004181 W JP2022004181 W JP 2022004181W WO 2022172846 A1 WO2022172846 A1 WO 2022172846A1
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WO
WIPO (PCT)
Prior art keywords
bearing
piston rod
retaining wall
insertion hole
piston
Prior art date
Application number
PCT/JP2022/004181
Other languages
French (fr)
Japanese (ja)
Inventor
佑介 高橋
俊雄 小林
Original Assignee
Ｋｙｂ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ｋｙｂ株式会社 filed Critical Ｋｙｂ株式会社
Priority to KR1020237026392A priority Critical patent/KR20230137924A/en
Priority to CN202280013966.1A priority patent/CN116848329A/en
Publication of WO2022172846A1 publication Critical patent/WO2022172846A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members

Definitions

  • the present invention relates to fluid pressure cylinders.
  • JP 2013-199950A discloses a fluid pressure cylinder in which a piston rod to which a piston is fastened is reciprocally provided in a cylinder tube, the cylinder head closing an end opening of the cylinder tube.
  • a fluid pressure cylinder is disclosed in which a bearing is interposed by a snap ring on the inner peripheral surface.
  • the present invention has been made in view of the above problems, and an object of the present invention is to prevent a bearing from coming off with a simple structure.
  • the present invention is a fluid pressure cylinder in which a piston rod provided with a piston is reciprocably provided in a cylinder tube, wherein an end opening of the cylinder tube is closed and an insertion hole through which the piston rod is inserted is formed.
  • a bearing provided in the closing member for slidably supporting the piston rod; and a pressure chamber partitioned between the closing member and the piston, the closing member extending into the insertion hole. It has a bearing housing groove formed on the peripheral surface and housing the bearing.
  • the bearing housing groove has a groove bottom with which the outer peripheral surface of the bearing abuts, and a retaining wall that prevents the bearing from coming off toward the pressure chamber.
  • the retaining wall is characterized in that its height is greater than the clearance between the bearing and the piston rod.
  • FIG. 1 is a cross-sectional view of a fluid pressure cylinder according to an embodiment of the present invention
  • FIG. FIG. 2 is an enlarged view of a portion A surrounded by a dashed line in FIG. 1;
  • FIG. 1 is a sectional view around a cylinder head 40 of a hydraulic cylinder 100.
  • the hydraulic cylinder 100 is used as an actuator mounted on construction machinery and industrial machinery.
  • the hydraulic cylinder 100 is used as an arm cylinder mounted on a hydraulic excavator, and the arm of the hydraulic excavator rotates as the hydraulic cylinder 100 expands and contracts.
  • the hydraulic cylinder 100 includes a cylindrical cylinder tube 10, and a rod-side chamber 11 and an anti-rod-side chamber 12 which are slidably inserted into the cylinder tube 10 and which serve as pressure chambers.
  • the inside of the cylinder tube 10 is partitioned by the piston 20 into two fluid pressure chambers, a rod-side chamber 11 as a pressure chamber and a non-rod-side chamber 12 .
  • the hydraulic cylinder 100 is expanded and contracted along the axial direction by hydraulic pressure led from the hydraulic source to the rod-side chamber 11 or the anti-rod-side chamber 12 .
  • a working fluid such as a water-soluble substitute fluid may be used instead of oil as the hydraulic fluid.
  • the cylinder head 40 is a substantially cylindrical member having an insertion hole 41 through which the piston rod 30 is inserted. Cylinder head 40 is coupled to flange portion 10 a formed at the end of cylinder tube 10 via bolt 39 .
  • a bearing 55 , a sub-seal 56 , a main seal 57 and a dust seal 58 are arranged outward in this order on the inner peripheral surface of the insertion hole 41 . These are in sliding contact with the outer peripheral surface of the piston rod 30 , and particularly the bearing 55 supports the piston rod 30 so as to be slidable in the axial direction of the cylinder tube 10 .
  • the bearing 55 is a cylindrical bearing made of a mixed material in which resin is dispersed in a metal such as an alloy, it has a certain degree of flexibility.
  • the cylinder head 40 is provided with a supply/discharge port 42 for supplying/discharging hydraulic oil to/from the rod-side chamber 11 .
  • a supply/discharge port 42 opens to the inner peripheral surface of the insertion hole 41 , and the other end of the supply/discharge port 42 opens to the outer surface of the cylinder head 40 .
  • a hydraulic pipe (not shown) is connected to the other end of the supply/discharge port 42, and the hydraulic pipe is connected to a hydraulic source or a tank through a switching valve.
  • the cylinder head 40 is provided with a cylindrical portion 45 that fits into the inner peripheral surface of the flange portion 10 a of the cylinder tube 10 .
  • An O-ring 59 for sealing between the cylinder tube 10 and the cylinder head 40 is provided on the outer peripheral surface of the cylindrical portion 45 .
  • the tip surface of the cylindrical portion 45 functions as a restricting surface that the piston 20 comes into contact with when the hydraulic cylinder 100 is most extended and restricts movement of the piston 20 and the piston rod 30 .
  • the insertion hole 41 has a first insertion hole 41a into which a cushion ring 34, which will be described later, can enter, and a second insertion hole 41b having an inner diameter smaller than that of the first insertion hole 41a.
  • the first insertion hole 41a is provided on the cylindrical portion 45 side, and the second insertion hole 41b is provided on the opposite side of the supply/discharge port 42 from the first insertion hole 41a.
  • the piston rod 30 includes a small-diameter portion 31 formed at the tip portion to which the piston 20 is fastened, a large-diameter portion 32 having an outer diameter larger than that of the small-diameter portion 31 and slidably supported by the cylinder head 40, and a small-diameter portion 31 and a large-diameter portion 32 . and a medium-diameter portion 33 formed between the diameter portions 32 and having a cushion ring 34 arranged radially outward. Since the outer diameter of the medium-diameter portion 33 and the inner diameter of the cushion ring 34 are set smaller than the outer diameters of the large-diameter portion 32 and the piston 20 , the cushion ring 34 does not slip out of the piston rod 30 .
  • the cushion ring 34 is a cylindrical member having an outer diameter that can be inserted into the first insertion hole 41a of the cylinder head 40, and serves to reduce the moving speed of the piston rod 30 when the hydraulic cylinder 100 reaches the most extended state.
  • the hydraulic oil in the rod-side chamber 11 flows between the outer peripheral surface of the large-diameter portion 32 and the inner peripheral surface of the first insertion hole 41a. It is led to the supply/discharge port 42 through a passage having a relatively large cross-sectional area formed therebetween. Therefore, the piston rod 30 can move at a relatively high speed.
  • the cushion ring 34 enters the first insertion hole 41a, the cross-sectional area of the passage connecting the supply/discharge port 42 and the rod-side chamber 11 gradually decreases, so the moving speed of the piston rod 30 further decreases. In this manner, the cushion ring 34 exerts a cushioning action, and the piston 20 is prevented from colliding with the cylinder head 40 with force.
  • a bearing housing groove 51, a sub-seal housing groove 52, a main seal housing groove 53, and a dust seal housing groove 54 are arranged outward in this order on the inner peripheral surface of the second insertion hole 41b. formed by The bearing 55, the sub-seal 56, the main seal 57 and the dust seal 58 are housed (mounted) in the bearing housing groove 51, the sub-seal housing groove 52, the main seal housing groove 53 and the dust seal housing groove 54, respectively. The sub-seal 56 , main seal 57 and dust seal 58 are in sliding contact with the outer peripheral surface of the piston rod 30 .
  • the bearing receiving groove 51 includes a groove bottom portion 511 extending along the axial direction and a retainer portion provided on one side of the groove bottom portion 511 in the axial direction to partition the bearing receiving groove 51 . It has a wall 512 and a regulation wall 513 provided on the other side in the axial direction of the groove bottom 511 and partitioning the bearing housing groove 51 .
  • the groove bottom 511 is formed so that its diameter is approximately equal to the outer diameter of the bearing 55 .
  • the outer peripheral surface of the bearing 55 contacts the groove bottom 511 .
  • the groove bottom portion 511 is formed so that its diameter is smaller than the inner diameter of the first insertion hole 41a. That is, the first insertion hole 41 a is formed so that its inner diameter is larger than the outer diameter of the bearing 55 . Accordingly, the bearing 55 can smoothly pass through the first insertion hole 41a and enter the second insertion hole 41b without being press-fitted.
  • the retaining wall 512 is an annular wall for preventing the bearing 55 from coming off toward the rod-side chamber 11 side.
  • the retaining wall 512 is formed to protrude from the groove bottom 511 toward the axis O along the radial direction.
  • the retaining wall 512 When the large-diameter portion 32 of the piston rod 30 is inserted through the cylinder head 40 , the retaining wall 512 has a height h1 of the bearing 55 accommodated in the bearing accommodation groove 51 and the large-diameter portion 32 of the piston rod 30 . is larger than the clearance c1 between and (see FIG. 2). Specifically, the clearance c ⁇ b>1 is the radial dimension between the inner peripheral surface of the bearing 55 and the outer peripheral surface of the large diameter portion 32 .
  • the retaining wall 512 is such that the clearance c3 between the vertex 512 c and the large-diameter portion 32 of the piston rod 30 is the thickness of the bearing 55 .
  • d ie, the dimension between the inner peripheral surface of bearing 55 and the outer peripheral surface of bearing 55
  • the bearing 55 does not pass through the clearance c3 between the apex 512c of the retaining wall 512 and the large-diameter portion 32 of the piston rod 30, so that the bearing 55 climbs over the retaining wall 512 and moves into the bearing receiving groove 51. I can't get out of
  • the retaining wall 512 has a height h ⁇ b>1 (that is, the amount of protrusion of the retaining wall 512 from the groove bottom 511 ) smaller than the thickness d of the bearing 55 .
  • the height of the retaining wall 512 can be reduced, so that the amount of deformation of the bearing 55 during press-fitting can be reduced.
  • the retaining wall 512 has a first tapered portion 512 a that guides the bearing 55 to the groove bottom portion 511 and a second tapered portion 512 b that faces the end surface 55 a of the bearing 55 .
  • the first tapered portion 512a is directly continuous with the second tapered portion 512b in the axial direction, but is not limited to this. It may be connected indirectly to the second tapered portion 512b through the flat portion.
  • the first tapered portion 512a is formed such that the clearance between it and the large diameter portion 32 of the piston rod 30 gradually decreases toward the outside (the side opposite to the piston). As a result, the bearing 55 is smoothly press-fitted into the bearing housing groove 51 while being guided by the first tapered portion 512a.
  • the inclination angle ⁇ of the first tapered portion 512a is preferably 60° or less, more preferably 45° or less, and 30° or less. is more preferred.
  • the inclination angle ⁇ of the first tapered portion 512a is 20°.
  • the inner diameter of the end portion 512 d of the first tapered portion 512 a is larger than the inner diameter of the groove bottom portion 511 . This makes it easier to insert the bearing 55 into the bearing receiving groove 51 .
  • the second tapered portion 512b is formed so that the clearance between it and the large diameter portion 32 of the piston rod 30 gradually increases toward the outside. As a result, machining of the cylinder head 40 is facilitated compared to the bearing housing groove 51 in which the second tapered portion 512b is not formed. From the viewpoint of making it difficult for the bearing 55 to come off, it is preferable to make the inclination angle ⁇ of the second tapered portion 512b larger than the inclination angle ⁇ of the first tapered portion 512a. In addition, in this embodiment, the inclination angle ⁇ of the second tapered portion 512b is 30°.
  • the restricting wall 513 is an annular wall that faces the retaining wall 512 and restricts axial movement of the bearing 55 .
  • the restricting wall 513 is formed to protrude from the groove bottom 511 toward the axis O along the radial direction.
  • the restricting wall 513 has a height h2 (that is, the amount of protrusion of the restricting wall 513 from the groove bottom 511) that is greater than the height h1 of the retaining wall 512 (see FIG. 2).
  • the height of the retaining wall 512 can be reduced, so that the amount of deformation of the bearing 55 during press-fitting can be reduced.
  • the regulation wall 513 does not contact the large diameter portion 32 of the piston rod 30 .
  • the clearance c2 between the regulation wall 513 and the large diameter portion 32 of the piston rod 30 is equal to the clearance c1 between the bearing 55 and the large diameter portion 32 of the piston rod 30 (see FIG. 2).
  • a hydraulic cylinder 100 is a hydraulic cylinder 100 in which a piston rod 30 provided with a piston 20 is reciprocally provided in a cylinder tube 10, and closes an end opening of the cylinder tube 10. , a cylinder head 40 having an insertion hole 41 through which the piston rod 30 is inserted; a bearing 55 provided in the cylinder head 40 for slidably supporting the piston rod 30; and a partitioned rod-side chamber 11 .
  • the cylinder head 40 has a bearing housing groove 51 formed in the inner peripheral surface of the insertion hole 41 and housing a bearing 55 .
  • the bearing housing groove 51 has a groove bottom 511 with which the outer peripheral surface of the bearing 55 abuts, and a retaining wall 512 that restricts the bearing 55 from coming off toward the rod-side chamber 11.
  • the retaining wall 512 has a height of greater than the clearance between bearing 55 and piston rod 30.
  • the bearing receiving groove 51 is formed on the inner peripheral surface of the insertion hole 41 of the cylinder head 40 , the bearing 55 can be displaced when the piston rod 30 is not inserted through the insertion hole 41 of the cylinder head 40 . are housed in the bearing housing groove 51 by press fitting. Further, since the height h1 of the retaining wall 512 that restricts the bearing 55 from coming off toward the rod-side chamber 11 is greater than the clearance c1 between the bearing 55 and the piston rod 30, the piston is inserted into the insertion hole 41 of the cylinder head 40. In the state in which the rod 30 is inserted, the bearing 55 does not get over the retaining wall 512 and come out of the bearing receiving groove 51 . Therefore, it is possible to prevent the bearing 55 from coming off with a simple structure without using a snap ring.
  • the bearing 55 is press-fitted into the bearing receiving groove 51 via the retaining wall 512 , and the retaining wall 512 has a first tapered portion 512 a that guides the bearing 55 to the groove bottom 511 . It is formed.
  • the bearing 55 is smoothly press-fitted into the bearing housing groove 51 while being guided by the first tapered portion 512a, so the mountability of the bearing 55 is improved.
  • the retaining wall 512 is formed with a second tapered portion 512b facing the end surface of the bearing 55, and the inclination angle ⁇ of the second tapered portion 512b is larger than the inclination angle ⁇ of the first tapered portion 512a. big.
  • the workability of the cylinder head 40 is improved compared to the bearing housing groove 51 in which the second tapered portion 512b is not formed. Further, by making the inclination angle ⁇ of the second tapered portion 512b larger than the inclination angle ⁇ of the first tapered portion 512a, the bearing 55 is less likely to come off.
  • the bearing receiving groove 51 further has a restricting wall 513 that faces the retaining wall 512 and restricts axial movement of the bearing 55.
  • the restricting wall 513 has a height h2 of the retaining wall. 512 is greater than the height h1. According to this, the height of the retaining wall 512 can be reduced, so that the amount of deformation of the bearing 55 at the time of press-fitting can be reduced.
  • the retaining wall 512 is formed along the entire circumference of the ring, but is not limited to this. A plurality of spaces may be formed.
  • the retaining wall 512 has the first tapered portion 512a and the second tapered portion 512b that is continuous with the first tapered portion 512a. Only the first tapered portion 512a may be formed without forming the portion 512b. In this case, the space for forming the second tapered portion 512b can be saved compared to the retaining wall 512 in which the first tapered portion 512a and the second tapered portion 512b are formed. Miniaturization can be achieved.
  • the regulation wall 513 is provided so that the clearance c2 between the piston rod 30 and the large diameter portion 32 is equal to the clearance c1 between the bearing 55 and the piston rod 30 large diameter portion 32.
  • the clearance c2 between the large diameter portion 32 of the piston rod 30 is larger than the clearance c1 between the bearing 55 and the large diameter portion 32 of the piston rod 30. It may be provided to be large. In this case, contact between the regulation wall 513 and the large diameter portion 32 of the piston rod 30 can be prevented.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)

Abstract

A hydraulic cylinder (100) that comprises: a cylinder head (40) that closes an end part opening part of a cylinder tube (10) and has formed therein an insertion hole (41) through which a piston rod (30) is inserted; a bearing (55) that is provided to the cylinder head (40) and slidably supports the piston rod (30); and a rod-side chamber (11) that is formed between the cylinder head (40) and a piston (20). The cylinder head (40) has a bearing accommodation groove (51) that is formed in the inner circumferential surface of the insertion hole (41) and accommodates the bearing (55). The bearing accommodation groove (51) has: a groove bottom part (511) that is abutted by the outer circumferential surface of the bearing (55); and a retaining wall (512) that keeps the bearing (55) from slipping onto the rod-side chamber (11) side. The height (h1) of the retaining wall (512) is greater than the clearance (c1) between the bearing (55) and the piston rod (30).

Description

流体圧シリンダhydraulic cylinder
　本発明は、流体圧シリンダに関するものである。 The present invention relates to fluid pressure cylinders.
　ＪＰ２０１３－１９９９５０Ａには、ピストンが締結されたピストンロッドがシリンダチューブ内に往復動可能に設けられた流体圧シリンダであって、シリンダチューブの端部開口部を閉塞するシリンダヘッドを備え、シリンダヘッドの内周面に、軸受がスナップリングによって介装される流体圧シリンダが開示されている。 JP 2013-199950A discloses a fluid pressure cylinder in which a piston rod to which a piston is fastened is reciprocally provided in a cylinder tube, the cylinder head closing an end opening of the cylinder tube. A fluid pressure cylinder is disclosed in which a bearing is interposed by a snap ring on the inner peripheral surface.
　ＪＰ２０１３－１９９９５０Ａに記載の流体圧シリンダでは、軸受をシリンダヘッドの内周面に介装するには、軸受の抜けを防止するためのスナップリングを用いる必要がある。このため、流体圧シリンダを構成する部品点数が多い。また、スナップリングを設けるための溝を別途形成しなければならない。このように、特許文献１に記載の流体圧シリンダでは、軸受の抜けを防止するための構造が複雑である。 In the fluid pressure cylinder described in JP2013-199950A, it is necessary to use a snap ring to prevent the bearing from slipping out in order to mount the bearing on the inner peripheral surface of the cylinder head. Therefore, the number of parts constituting the fluid pressure cylinder is large. Also, a groove for installing the snap ring must be formed separately. Thus, the fluid pressure cylinder disclosed in Patent Document 1 has a complicated structure for preventing the bearing from coming off.
　本発明は、上記の問題点に鑑みてなされたものであり、簡素な構造で軸受の抜けを防止することを目的とする。 The present invention has been made in view of the above problems, and an object of the present invention is to prevent a bearing from coming off with a simple structure.
　本発明は、ピストンが設けられたピストンロッドがシリンダチューブ内に往復動可能に設けられた流体圧シリンダであって、シリンダチューブの端部開口部を閉塞し、ピストンロッドが挿通する挿通孔が形成された閉塞部材と、閉塞部材に設けられ、ピストンロッドを摺動自在に支持する軸受と、閉塞部材とピストンとの間に区画された圧力室と、を備え、閉塞部材は、挿通孔の内周面に形成され軸受が収容される軸受収容溝を有し、軸受収容溝は、軸受の外周面が当接する溝底部と、圧力室側への軸受の抜けを規制する抜止壁と、を有し、抜止壁は、その高さが軸受とピストンロッドとの間のクリアランスよりも大きいことを特徴とする。 The present invention is a fluid pressure cylinder in which a piston rod provided with a piston is reciprocably provided in a cylinder tube, wherein an end opening of the cylinder tube is closed and an insertion hole through which the piston rod is inserted is formed. a bearing provided in the closing member for slidably supporting the piston rod; and a pressure chamber partitioned between the closing member and the piston, the closing member extending into the insertion hole. It has a bearing housing groove formed on the peripheral surface and housing the bearing. The bearing housing groove has a groove bottom with which the outer peripheral surface of the bearing abuts, and a retaining wall that prevents the bearing from coming off toward the pressure chamber. The retaining wall is characterized in that its height is greater than the clearance between the bearing and the piston rod.
本発明の実施形態に係る流体圧シリンダの断面図である。1 is a cross-sectional view of a fluid pressure cylinder according to an embodiment of the present invention; FIG. 図１における一点鎖線で囲まれた部分Ａの拡大図である。FIG. 2 is an enlarged view of a portion A surrounded by a dashed line in FIG. 1;
　以下、図面を参照して、本発明の実施形態について説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　図１を参照して、本発明の実施形態に係る流体圧シリンダについて説明する。以下では、流体圧シリンダが作動油を作動流体として駆動する油圧シリンダ１００である場合について説明する。図１は、油圧シリンダ１００のシリンダヘッド４０周辺の断面図である。 A fluid pressure cylinder according to an embodiment of the present invention will be described with reference to FIG. Below, the case where the fluid pressure cylinder is the hydraulic cylinder 100 that drives hydraulic oil as the working fluid will be described. FIG. 1 is a sectional view around a cylinder head 40 of a hydraulic cylinder 100. FIG.
　油圧シリンダ１００は、建設機械や産業機械に搭載されるアクチュエータとして用いられるものである。例えば、油圧シリンダ１００は、油圧ショベルに搭載されるアームシリンダとして用いられ、油圧シリンダ１００が伸縮作動することによって、油圧ショベルのアームが回動する。 The hydraulic cylinder 100 is used as an actuator mounted on construction machinery and industrial machinery. For example, the hydraulic cylinder 100 is used as an arm cylinder mounted on a hydraulic excavator, and the arm of the hydraulic excavator rotates as the hydraulic cylinder 100 expands and contracts.
　図１に示すように、油圧シリンダ１００は、筒状のシリンダチューブ１０と、シリンダチューブ１０内に摺動自在に挿通されシリンダチューブ１０内を圧力室としてのロッド側室１１と反ロッド側室１２とに仕切るピストン２０と、一端にピストン２０が連結され他端がシリンダチューブ１０の外部へと延在しシリンダチューブ１０内を往復動するピストンロッド３０と、シリンダチューブ１０の端部開口部を閉塞する閉塞部材としてのシリンダヘッド４０と、を備える。 As shown in FIG. 1, the hydraulic cylinder 100 includes a cylindrical cylinder tube 10, and a rod-side chamber 11 and an anti-rod-side chamber 12 which are slidably inserted into the cylinder tube 10 and which serve as pressure chambers. A partitioning piston 20, a piston rod 30 having one end connected to the piston 20 and the other end extending to the outside of the cylinder tube 10 and reciprocating within the cylinder tube 10, and a block closing the end opening of the cylinder tube 10 and a cylinder head 40 as a member.
　シリンダチューブ１０の内部は、ピストン２０によって圧力室としてのロッド側室１１と反ロッド側室１２との２つの流体圧室に仕切られる。油圧シリンダ１００は、油圧源からロッド側室１１又は反ロッド側室１２に導かれる作動油圧により軸方向に沿って伸縮作動する。なお、作動油としてオイルの代わりに例えば水溶性代替液等の作動流体を用いてもよい。 The inside of the cylinder tube 10 is partitioned by the piston 20 into two fluid pressure chambers, a rod-side chamber 11 as a pressure chamber and a non-rod-side chamber 12 . The hydraulic cylinder 100 is expanded and contracted along the axial direction by hydraulic pressure led from the hydraulic source to the rod-side chamber 11 or the anti-rod-side chamber 12 . A working fluid such as a water-soluble substitute fluid may be used instead of oil as the hydraulic fluid.
　シリンダヘッド４０は、ピストンロッド３０が挿通する挿通孔４１が貫通して形成された略円筒状の部材である。シリンダヘッド４０は、ボルト３９を介してシリンダチューブ１０の端部に形成されたフランジ部１０ａに結合される。 The cylinder head 40 is a substantially cylindrical member having an insertion hole 41 through which the piston rod 30 is inserted. Cylinder head 40 is coupled to flange portion 10 a formed at the end of cylinder tube 10 via bolt 39 .
　挿通孔４１の内周面には、軸受５５、サブシール５６、メインシール５７及びダストシール５８が、外側に向かってこの順に並んで設けられる。これらはピストンロッド３０の外周面に摺接し、特に軸受５５はピストンロッド３０をシリンダチューブ１０の軸方向に摺動自在に支持する。また、軸受５５は合金等の金属に樹脂を分散させた混合材質からなる円筒状の軸受であるため、一定の可撓性を有する。 A bearing 55 , a sub-seal 56 , a main seal 57 and a dust seal 58 are arranged outward in this order on the inner peripheral surface of the insertion hole 41 . These are in sliding contact with the outer peripheral surface of the piston rod 30 , and particularly the bearing 55 supports the piston rod 30 so as to be slidable in the axial direction of the cylinder tube 10 . Moreover, since the bearing 55 is a cylindrical bearing made of a mixed material in which resin is dispersed in a metal such as an alloy, it has a certain degree of flexibility.
　また、シリンダヘッド４０には、ロッド側室１１に対して作動油を給排する給排ポート４２が設けられる。給排ポート４２の一端は、挿通孔４１の内周面に開口しており、給排ポート４２の他端は、シリンダヘッド４０の外面に開口している。給排ポート４２の他端には図示しない油圧配管が接続され、油圧配管は切換弁を通じて油圧源又はタンクに接続される。 In addition, the cylinder head 40 is provided with a supply/discharge port 42 for supplying/discharging hydraulic oil to/from the rod-side chamber 11 . One end of the supply/discharge port 42 opens to the inner peripheral surface of the insertion hole 41 , and the other end of the supply/discharge port 42 opens to the outer surface of the cylinder head 40 . A hydraulic pipe (not shown) is connected to the other end of the supply/discharge port 42, and the hydraulic pipe is connected to a hydraulic source or a tank through a switching valve.
　また、シリンダヘッド４０には、シリンダチューブ１０のフランジ部１０ａの内周面に嵌合する円筒部４５が設けられる。円筒部４５の外周面には、シリンダチューブ１０とシリンダヘッド４０との間をシールするＯリング５９が設けられる。円筒部４５の先端面は、油圧シリンダ１００が最も伸長した際にピストン２０が当接し、ピストン２０及びピストンロッド３０の移動を規制する規制面として機能する。 Also, the cylinder head 40 is provided with a cylindrical portion 45 that fits into the inner peripheral surface of the flange portion 10 a of the cylinder tube 10 . An O-ring 59 for sealing between the cylinder tube 10 and the cylinder head 40 is provided on the outer peripheral surface of the cylindrical portion 45 . The tip surface of the cylindrical portion 45 functions as a restricting surface that the piston 20 comes into contact with when the hydraulic cylinder 100 is most extended and restricts movement of the piston 20 and the piston rod 30 .
　また、挿通孔４１は、後述のクッションリング３４が進入可能な第１挿通孔４１ａと、第１挿通孔４１ａよりも内径が小さい第２挿通孔４１ｂと、を有する。第１挿通孔４１ａは、円筒部４５側に設けられ、第２挿通孔４１ｂは、給排ポート４２を挟んで第１挿通孔４１ａとは反対側に設けられる。 Further, the insertion hole 41 has a first insertion hole 41a into which a cushion ring 34, which will be described later, can enter, and a second insertion hole 41b having an inner diameter smaller than that of the first insertion hole 41a. The first insertion hole 41a is provided on the cylindrical portion 45 side, and the second insertion hole 41b is provided on the opposite side of the supply/discharge port 42 from the first insertion hole 41a.
　ピストンロッド３０は、先端部に形成されピストン２０が締結される小径部３１と、小径部３１よりも外径が大きくシリンダヘッド４０により摺動支持される大径部３２と、小径部３１と大径部３２の間に形成され径方向外側にクッションリング３４が配置される中径部３３と、を有する。中径部３３の外径及びクッションリング３４の内径は、大径部３２及びピストン２０の外径よりも小さく設定されているため、クッションリング３４がピストンロッド３０から抜け出ることはない。 The piston rod 30 includes a small-diameter portion 31 formed at the tip portion to which the piston 20 is fastened, a large-diameter portion 32 having an outer diameter larger than that of the small-diameter portion 31 and slidably supported by the cylinder head 40, and a small-diameter portion 31 and a large-diameter portion 32 . and a medium-diameter portion 33 formed between the diameter portions 32 and having a cushion ring 34 arranged radially outward. Since the outer diameter of the medium-diameter portion 33 and the inner diameter of the cushion ring 34 are set smaller than the outer diameters of the large-diameter portion 32 and the piston 20 , the cushion ring 34 does not slip out of the piston rod 30 .
　クッションリング３４は、シリンダヘッド４０の第１挿通孔４１ａに進入可能な外径を有する筒状部材であり、油圧シリンダ１００が最も伸長した状態に至る際にピストンロッド３０の移動速度を減速させるために設けられる。 The cushion ring 34 is a cylindrical member having an outer diameter that can be inserted into the first insertion hole 41a of the cylinder head 40, and serves to reduce the moving speed of the piston rod 30 when the hydraulic cylinder 100 reaches the most extended state. provided in
　次に、上記構成の油圧シリンダ１００の作動について説明する。 Next, the operation of the hydraulic cylinder 100 configured as described above will be described.
　反ロッド側室１２に油圧源が連通し、ロッド側室１１にタンクが連通すると、反ロッド側室１２に作動油が供給され、ロッド側室１１の作動油が給排ポート４２を通じてタンクへと排出される。これにより、ピストンロッド３０が図１の左方向に移動して油圧シリンダ１００は伸長作動する。 When the oil pressure source communicates with the anti-rod side chamber 12 and the tank communicates with the rod side chamber 11, hydraulic oil is supplied to the anti-rod side chamber 12, and the hydraulic oil in the rod side chamber 11 is discharged through the supply/discharge port 42 to the tank. As a result, the piston rod 30 moves leftward in FIG. 1 and the hydraulic cylinder 100 is extended.
　油圧シリンダ１００が伸長する際にクッションリング３４が第１挿通孔４１ａに進入するまでは、ロッド側室１１の作動油は、大径部３２の外周面と第１挿通孔４１ａの内周面との間に形成される比較的断面積が大きい通路を通じて給排ポート４２へ導かれる。このため、ピストンロッド３０は、比較的早い速度で移動可能である。 Until the cushion ring 34 enters the first insertion hole 41a when the hydraulic cylinder 100 extends, the hydraulic oil in the rod-side chamber 11 flows between the outer peripheral surface of the large-diameter portion 32 and the inner peripheral surface of the first insertion hole 41a. It is led to the supply/discharge port 42 through a passage having a relatively large cross-sectional area formed therebetween. Therefore, the piston rod 30 can move at a relatively high speed.
　油圧シリンダ１００がさらに伸長し、クッションリング３４が第１挿通孔４１ａに進入すると、ロッド側室１１の作動油は、クッションリング３４の内周面と中径部３３の外周面との間及びクッションリング３４の外周面と第１挿通孔４１ａの内周面との間に形成される比較的断面積が小さい通路を通じて給排ポート４２へ導かれることになる。 When the hydraulic cylinder 100 is further extended and the cushion ring 34 enters the first insertion hole 41a, the hydraulic oil in the rod side chamber 11 flows between the inner peripheral surface of the cushion ring 34 and the outer peripheral surface of the intermediate diameter portion 33 and the cushion ring 34 and the inner peripheral surface of the first insertion hole 41a.
　このように、給排ポート４２とロッド側室１１とを連通する通路の断面積が小さいと、給排ポート４２へ向かう作動油の流れに抵抗が付与され、結果として、ロッド側室１１の圧力が上昇し、ピストンロッド３０の移動速度は遅くなる。 When the cross-sectional area of the passage communicating between the supply/discharge port 42 and the rod side chamber 11 is small in this way, resistance is applied to the flow of hydraulic oil toward the supply/discharge port 42, and as a result, the pressure in the rod side chamber 11 increases. Then, the moving speed of the piston rod 30 becomes slow.
　また、クッションリング３４が第１挿通孔４１ａに進入するにつれて、給排ポート４２とロッド側室１１とを連通する通路の断面積は徐々に小さくなるため、ピストンロッド３０の移動速度はさらに遅くなる。このようにして、クッションリング３４によるクッション作用が発揮され、ピストン２０がシリンダヘッド４０に勢いよく衝突してしまうことが防止される。 Further, as the cushion ring 34 enters the first insertion hole 41a, the cross-sectional area of the passage connecting the supply/discharge port 42 and the rod-side chamber 11 gradually decreases, so the moving speed of the piston rod 30 further decreases. In this manner, the cushion ring 34 exerts a cushioning action, and the piston 20 is prevented from colliding with the cylinder head 40 with force.
　一方、ロッド側室１１に油圧源が連通し、反ロッド側室１２にタンクが連通すると、ロッド側室１１に給排ポート４２を通じて作動油が供給され、反ロッド側室１２の作動油がタンクへと排出される。これにより、ピストンロッド３０が図１の右方向に移動して油圧シリンダ１００は収縮作動する。 On the other hand, when the oil pressure source communicates with the rod side chamber 11 and the tank communicates with the anti-rod side chamber 12, hydraulic fluid is supplied to the rod side chamber 11 through the supply/discharge port 42, and the hydraulic fluid in the anti-rod side chamber 12 is discharged to the tank. be. As a result, the piston rod 30 moves rightward in FIG. 1 and the hydraulic cylinder 100 contracts.
　次に、図１及び図２を参照して、第２挿通孔４１ｂについて説明する。 Next, the second insertion hole 41b will be described with reference to FIGS. 1 and 2. FIG.
　図１及び図２に示すように、第２挿通孔４１ｂの内周面には、軸受収容溝５１、サブシール収容溝５２、メインシール収容溝５３及びダストシール収納溝５４が外側に向かってこの順に並んで形成される。軸受５５、サブシール５６、メインシール５７及びダストシール５８は、それぞれ軸受収容溝５１、サブシール収容溝５２、メインシール収容溝５３及びダストシール収納溝５４に収容（装着）される。サブシール５６、メインシール５７及びダストシール５８は、ピストンロッド３０の外周面に摺接する。 As shown in FIGS. 1 and 2, a bearing housing groove 51, a sub-seal housing groove 52, a main seal housing groove 53, and a dust seal housing groove 54 are arranged outward in this order on the inner peripheral surface of the second insertion hole 41b. formed by The bearing 55, the sub-seal 56, the main seal 57 and the dust seal 58 are housed (mounted) in the bearing housing groove 51, the sub-seal housing groove 52, the main seal housing groove 53 and the dust seal housing groove 54, respectively. The sub-seal 56 , main seal 57 and dust seal 58 are in sliding contact with the outer peripheral surface of the piston rod 30 .
　図２に示すように、軸受収容溝５１は、軸方向に沿って延在して形成される溝底部５１１と、溝底部５１１における軸方向の一方側に設けられ軸受収容溝５１を区画する抜止壁５１２と、溝底部５１１における軸方向の他方側に設けられ軸受収容溝５１を区画する規制壁５１３と、を有する。 As shown in FIG. 2 , the bearing receiving groove 51 includes a groove bottom portion 511 extending along the axial direction and a retainer portion provided on one side of the groove bottom portion 511 in the axial direction to partition the bearing receiving groove 51 . It has a wall 512 and a regulation wall 513 provided on the other side in the axial direction of the groove bottom 511 and partitioning the bearing housing groove 51 .
　溝底部５１１は、その直径が軸受５５の外径とほぼ等しくなるように形成される。これにより、軸受５５が軸受収容溝５１に収容された状態において、軸受５５の外周面は溝底部５１１に当接する。また、溝底部５１１は、その直径が第１挿通孔４１ａの内径よりも小さくなるように形成される。すなわち、第１挿通孔４１ａは、その内径が軸受５５の外径よりも大きくなるように形成される。これにより、軸受５５は、圧入されることなく、スムーズに第１挿通孔４１ａを通過して第２挿通孔４１ｂに入り込むことができる。 The groove bottom 511 is formed so that its diameter is approximately equal to the outer diameter of the bearing 55 . As a result, when the bearing 55 is housed in the bearing housing groove 51 , the outer peripheral surface of the bearing 55 contacts the groove bottom 511 . Further, the groove bottom portion 511 is formed so that its diameter is smaller than the inner diameter of the first insertion hole 41a. That is, the first insertion hole 41 a is formed so that its inner diameter is larger than the outer diameter of the bearing 55 . Accordingly, the bearing 55 can smoothly pass through the first insertion hole 41a and enter the second insertion hole 41b without being press-fitted.
　抜止壁５１２は、ロッド側室１１側への軸受５５の抜けを防止するための環状の壁部である。抜止壁５１２は、溝底部５１１から径方向に沿って軸線Ｏに向かって突出して形成される。シリンダヘッド４０にピストンロッド３０の大径部３２が挿通されていない状態において、軸受５５は、圧入によって、抜止壁５１２を乗り越えて軸受収容溝５１に収容される。 The retaining wall 512 is an annular wall for preventing the bearing 55 from coming off toward the rod-side chamber 11 side. The retaining wall 512 is formed to protrude from the groove bottom 511 toward the axis O along the radial direction. When the large-diameter portion 32 of the piston rod 30 is not inserted through the cylinder head 40 , the bearing 55 is received in the bearing receiving groove 51 over the retaining wall 512 by press fitting.
　そして、シリンダヘッド４０にピストンロッド３０の大径部３２が挿通された状態において、抜止壁５１２は、その高さｈ１が軸受収容溝５１に収容された軸受５５とピストンロッド３０の大径部３２との間のクリアランスｃ１よりも大きい（図２参照）。具体的には、クリアランスｃ１とは、軸受５５の内周面と大径部３２の外周面との間の径方向の寸法である。 When the large-diameter portion 32 of the piston rod 30 is inserted through the cylinder head 40 , the retaining wall 512 has a height h1 of the bearing 55 accommodated in the bearing accommodation groove 51 and the large-diameter portion 32 of the piston rod 30 . is larger than the clearance c1 between and (see FIG. 2). Specifically, the clearance c<b>1 is the radial dimension between the inner peripheral surface of the bearing 55 and the outer peripheral surface of the large diameter portion 32 .
　すなわち、シリンダヘッド４０にピストンロッド３０の大径部３２が挿通された状態において、抜止壁５１２は、その頂点５１２ｃとピストンロッド３０の大径部３２との間のクリアランスｃ３が軸受５５の厚さｄ（すなわち、軸受５５の内周面と軸受５５の外周面との間の寸法）よりも小さい（図２参照）。これにより、軸受５５は、抜止壁５１２の頂点５１２ｃとピストンロッド３０の大径部３２との間のクリアランスｃ３を通過することがないので、軸受５５は、抜止壁５１２を乗り越えて軸受収容溝５１から抜けることがない。 That is, when the large-diameter portion 32 of the piston rod 30 is inserted through the cylinder head 40 , the retaining wall 512 is such that the clearance c3 between the vertex 512 c and the large-diameter portion 32 of the piston rod 30 is the thickness of the bearing 55 . d (ie, the dimension between the inner peripheral surface of bearing 55 and the outer peripheral surface of bearing 55) (see FIG. 2). As a result, the bearing 55 does not pass through the clearance c3 between the apex 512c of the retaining wall 512 and the large-diameter portion 32 of the piston rod 30, so that the bearing 55 climbs over the retaining wall 512 and moves into the bearing receiving groove 51. I can't get out of
　また、抜止壁５１２は、その高さｈ１（すなわち、溝底部５１１からの抜止壁５１２の突出量）が軸受５５の厚さｄよりも小さい。これにより、抜止壁５１２の高さを低くすることができるので、圧入時の軸受５５の変形量を小さく抑えることができる。 Also, the retaining wall 512 has a height h<b>1 (that is, the amount of protrusion of the retaining wall 512 from the groove bottom 511 ) smaller than the thickness d of the bearing 55 . As a result, the height of the retaining wall 512 can be reduced, so that the amount of deformation of the bearing 55 during press-fitting can be reduced.
　抜止壁５１２は、軸受５５を溝底部５１１へガイドする第１テーパ部５１２ａと、軸受５５の端面５５ａに対向する第２テーパ部５１２ｂと、を有する。なお、本実施形態では、第１テーパ部５１２ａは、軸方向において、第２テーパ部５１２ｂと直接に連続しているが、これに限定されるものではなく、例えば、軸方向に沿って延在する平坦部を介して第２テーパ部５１２ｂと間接に連続するようにしてもよい。 The retaining wall 512 has a first tapered portion 512 a that guides the bearing 55 to the groove bottom portion 511 and a second tapered portion 512 b that faces the end surface 55 a of the bearing 55 . In the present embodiment, the first tapered portion 512a is directly continuous with the second tapered portion 512b in the axial direction, but is not limited to this. It may be connected indirectly to the second tapered portion 512b through the flat portion.
　第１テーパ部５１２ａは、ピストンロッド３０の大径部３２との間のクリアランスが外側（反ピストン側）に向かって次第に小さくなるように形成される。これにより、軸受５５は、第１テーパ部５１２ａによってガイドされながらスムーズに軸受収容溝５１に圧入される。なお、軸受５５の圧入しやすさを向上させる観点から、第１テーパ部５１２ａの傾斜角αを６０°以下にすることが好ましく、４５°以下にすることがより好ましく、３０°以下にすることが更に好ましい。なお、本実施形態では、第１テーパ部５１２ａの傾斜角αは、２０°である。第１テーパ部５１２ａの端部５１２ｄにおける内径は、溝底部５１１の内径よりも大きい。これにより、軸受５５を軸受収容溝５１に挿入しやすくなる。 The first tapered portion 512a is formed such that the clearance between it and the large diameter portion 32 of the piston rod 30 gradually decreases toward the outside (the side opposite to the piston). As a result, the bearing 55 is smoothly press-fitted into the bearing housing groove 51 while being guided by the first tapered portion 512a. From the viewpoint of improving ease of press-fitting the bearing 55, the inclination angle α of the first tapered portion 512a is preferably 60° or less, more preferably 45° or less, and 30° or less. is more preferred. In addition, in this embodiment, the inclination angle α of the first tapered portion 512a is 20°. The inner diameter of the end portion 512 d of the first tapered portion 512 a is larger than the inner diameter of the groove bottom portion 511 . This makes it easier to insert the bearing 55 into the bearing receiving groove 51 .
　一方、第２テーパ部５１２ｂは、ピストンロッド３０の大径部３２との間のクリアランスが外側に向かって次第に大きくなるように形成される。これにより、第２テーパ部５１２ｂが形成されない軸受収容溝５１に比べ、シリンダヘッド４０の加工がしやすくなる。なお、軸受５５を抜けにくくする観点から、第２テーパ部５１２ｂの傾斜角βを第１テーパ部５１２ａの傾斜角αよりも大きくすることが好ましい。なお、本実施形態では、第２テーパ部５１２ｂの傾斜角βは、３０°である。 On the other hand, the second tapered portion 512b is formed so that the clearance between it and the large diameter portion 32 of the piston rod 30 gradually increases toward the outside. As a result, machining of the cylinder head 40 is facilitated compared to the bearing housing groove 51 in which the second tapered portion 512b is not formed. From the viewpoint of making it difficult for the bearing 55 to come off, it is preferable to make the inclination angle β of the second tapered portion 512b larger than the inclination angle α of the first tapered portion 512a. In addition, in this embodiment, the inclination angle β of the second tapered portion 512b is 30°.
　規制壁５１３は、抜止壁５１２に対向し、軸受５５の軸方向の移動を規制するための環状の壁部である。規制壁５１３は、溝底部５１１から径方向に沿って軸線Ｏに向かって突出して形成される。規制壁５１３は、その高さｈ２（すなわち、溝底部５１１からの規制壁５１３の突出量）が抜止壁５１２の高さｈ１よりも大きい（図２参照）。これにより、抜止壁５１２の高さを低くすることができるので、圧入時の軸受５５の変形量を小さく抑えることができる。 The restricting wall 513 is an annular wall that faces the retaining wall 512 and restricts axial movement of the bearing 55 . The restricting wall 513 is formed to protrude from the groove bottom 511 toward the axis O along the radial direction. The restricting wall 513 has a height h2 (that is, the amount of protrusion of the restricting wall 513 from the groove bottom 511) that is greater than the height h1 of the retaining wall 512 (see FIG. 2). As a result, the height of the retaining wall 512 can be reduced, so that the amount of deformation of the bearing 55 during press-fitting can be reduced.
　そして、シリンダヘッド４０にピストンロッド３０の大径部３２が挿通された状態において、規制壁５１３は、ピストンロッド３０の大径部３２と当接しない。規制壁５１３とピストンロッド３０の大径部３２との間のクリアランスｃ２は、軸受５５とピストンロッド３０の大径部３２との間のクリアランスｃ１と等しい（図２参照）。 Then, in a state where the large diameter portion 32 of the piston rod 30 is inserted through the cylinder head 40 , the regulation wall 513 does not contact the large diameter portion 32 of the piston rod 30 . The clearance c2 between the regulation wall 513 and the large diameter portion 32 of the piston rod 30 is equal to the clearance c1 between the bearing 55 and the large diameter portion 32 of the piston rod 30 (see FIG. 2).
　すなわち、シリンダヘッド４０にピストンロッド３０の大径部３２が挿通された状態において、規制壁５１３は、ピストンロッド３０の大径部３２との間のクリアランスｃ２が軸受５５の厚さｄよりも小さい（図２参照）。これにより、軸受５５は、規制壁５１３とピストンロッド３０の大径部３２との間のクリアランスｃ２を通過することができないため、軸受５５は、規制壁５１３を乗り越えて軸受収容溝５１から抜けることがない。 That is, when the large diameter portion 32 of the piston rod 30 is inserted through the cylinder head 40 , the clearance c2 between the regulation wall 513 and the large diameter portion 32 of the piston rod 30 is smaller than the thickness d of the bearing 55 . (See Figure 2). As a result, the bearing 55 cannot pass through the clearance c2 between the restricting wall 513 and the large-diameter portion 32 of the piston rod 30, so the bearing 55 can climb over the restricting wall 513 and come out of the bearing housing groove 51. There is no
　以下、本発明の実施形態の構成、作用及び効果をまとめて説明する。 The configurations, actions and effects of the embodiments of the present invention will be collectively described below.
　本実施形態に係る油圧シリンダ１００は、ピストン２０が設けられたピストンロッド３０がシリンダチューブ１０内に往復動可能に設けられた油圧シリンダ１００であって、シリンダチューブ１０の端部開口部を閉塞し、ピストンロッド３０が挿通する挿通孔４１が形成されたシリンダヘッド４０と、シリンダヘッド４０に設けられ、ピストンロッド３０を摺動自在に支持する軸受５５と、シリンダヘッド４０とピストン２０との間に区画されたロッド側室１１と、を備える。シリンダヘッド４０は、挿通孔４１の内周面に形成され軸受５５が収容される軸受収容溝５１を有する。軸受収容溝５１は、軸受５５の外周面が当接する溝底部５１１と、ロッド側室１１側への軸受５５の抜けを規制する抜止壁５１２と、を有し、抜止壁５１２は、その高さが軸受５５とピストンロッド３０との間のクリアランスよりも大きい。 A hydraulic cylinder 100 according to the present embodiment is a hydraulic cylinder 100 in which a piston rod 30 provided with a piston 20 is reciprocally provided in a cylinder tube 10, and closes an end opening of the cylinder tube 10. , a cylinder head 40 having an insertion hole 41 through which the piston rod 30 is inserted; a bearing 55 provided in the cylinder head 40 for slidably supporting the piston rod 30; and a partitioned rod-side chamber 11 . The cylinder head 40 has a bearing housing groove 51 formed in the inner peripheral surface of the insertion hole 41 and housing a bearing 55 . The bearing housing groove 51 has a groove bottom 511 with which the outer peripheral surface of the bearing 55 abuts, and a retaining wall 512 that restricts the bearing 55 from coming off toward the rod-side chamber 11. The retaining wall 512 has a height of greater than the clearance between bearing 55 and piston rod 30.
　この構成によれば、軸受収容溝５１は、シリンダヘッド４０の挿通孔４１の内周面に形成されるので、シリンダヘッド４０の挿通孔４１にピストンロッド３０が挿通されていない状態において、軸受５５は、圧入によって軸受収容溝５１に収容される。また、ロッド側室１１側への軸受５５の抜けを規制する抜止壁５１２の高さｈ１が、軸受５５とピストンロッド３０との間のクリアランスｃ１よりも大きいため、シリンダヘッド４０の挿通孔４１にピストンロッド３０が挿通された状態において、軸受５５は、抜止壁５１２を乗り越えて軸受収容溝５１から抜けることがない。したがって、スナップリングを用いることなく、簡素な構成で軸受５５の抜けを防止することができる。 According to this configuration, since the bearing receiving groove 51 is formed on the inner peripheral surface of the insertion hole 41 of the cylinder head 40 , the bearing 55 can be displaced when the piston rod 30 is not inserted through the insertion hole 41 of the cylinder head 40 . are housed in the bearing housing groove 51 by press fitting. Further, since the height h1 of the retaining wall 512 that restricts the bearing 55 from coming off toward the rod-side chamber 11 is greater than the clearance c1 between the bearing 55 and the piston rod 30, the piston is inserted into the insertion hole 41 of the cylinder head 40. In the state in which the rod 30 is inserted, the bearing 55 does not get over the retaining wall 512 and come out of the bearing receiving groove 51 . Therefore, it is possible to prevent the bearing 55 from coming off with a simple structure without using a snap ring.
　また、本実施形態において、軸受５５は、圧入によって、抜止壁５１２を経由して軸受収容溝５１に収容され、抜止壁５１２には、軸受５５を溝底部５１１へガイドする第１テーパ部５１２ａが形成される。 In this embodiment, the bearing 55 is press-fitted into the bearing receiving groove 51 via the retaining wall 512 , and the retaining wall 512 has a first tapered portion 512 a that guides the bearing 55 to the groove bottom 511 . It is formed.
　この構成によれば、軸受５５は、第１テーパ部５１２ａによってガイドされながらスムーズに軸受収容溝５１に圧入されるので、軸受５５の装着性が向上する。 According to this configuration, the bearing 55 is smoothly press-fitted into the bearing housing groove 51 while being guided by the first tapered portion 512a, so the mountability of the bearing 55 is improved.
　また、本実施形態において、抜止壁５１２には、軸受５５の端面に対向する第２テーパ部５１２ｂが形成され、第２テーパ部５１２ｂの傾斜角βが第１テーパ部５１２ａの傾斜角αよりも大きい。 Further, in the present embodiment, the retaining wall 512 is formed with a second tapered portion 512b facing the end surface of the bearing 55, and the inclination angle β of the second tapered portion 512b is larger than the inclination angle α of the first tapered portion 512a. big.
　この構成によれば、第２テーパ部５１２ｂが形成されない軸受収容溝５１に比べ、シリンダヘッド４０の加工性が向上する。また、第２テーパ部５１２ｂの傾斜角βを第１テーパ部５１２ａの傾斜角αよりも大きくすることにより、軸受５５が抜けにくくなる。 According to this configuration, the workability of the cylinder head 40 is improved compared to the bearing housing groove 51 in which the second tapered portion 512b is not formed. Further, by making the inclination angle β of the second tapered portion 512b larger than the inclination angle α of the first tapered portion 512a, the bearing 55 is less likely to come off.
　また、本実施形態において、軸受収容溝５１は、抜止壁５１２に対向し、軸受５５の軸方向の移動を規制する規制壁５１３をさらに有し、規制壁５１３は、その高さｈ２が抜止壁５１２の高さｈ１よりも大きい。これによれば、抜止壁５１２の高さを低くすることができるので、圧入時の軸受５５の変形量を小さく抑えることができる。 In this embodiment, the bearing receiving groove 51 further has a restricting wall 513 that faces the retaining wall 512 and restricts axial movement of the bearing 55. The restricting wall 513 has a height h2 of the retaining wall. 512 is greater than the height h1. According to this, the height of the retaining wall 512 can be reduced, so that the amount of deformation of the bearing 55 at the time of press-fitting can be reduced.
　以上、本実施形態について説明したが、上記実施形態は、本発明の適用例の一部を示したに過ぎず、本発明の技術的範囲を上記実施形態の具体的構成に限定する趣旨ではない。 Although the present embodiment has been described above, the above embodiment merely shows a part of application examples of the present invention, and is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment. .
（変形例）
　上記実施形態では、抜止壁５１２は、環状の全周に形成されているが、これに限定されるものではなく、例えば、環状の一部に形成されてもよいし、環状に所定の間隔を空けて形成される複数のものであってもよい。 (Modification)
In the above embodiment, the retaining wall 512 is formed along the entire circumference of the ring, but is not limited to this. A plurality of spaces may be formed.
　上記実施形態では、抜止壁５１２は、第１テーパ部５１２ａ及び第１テーパ部５１２ａに連続する第２テーパ部５１２ｂが形成されているが、これに限定されるものではなく、例えば、第２テーパ部５１２ｂが形成されず、第１テーパ部５１２ａのみが形成されてもよい。この場合、第１テーパ部５１２ａ及び第２テーパ部５１２ｂが形成される抜止壁５１２に比べ、第２テーパ部５１２ｂを形成するためのスペースを省くことができるので、軸受収容溝５１の軸方向の小型化を図ることができる。 In the above-described embodiment, the retaining wall 512 has the first tapered portion 512a and the second tapered portion 512b that is continuous with the first tapered portion 512a. Only the first tapered portion 512a may be formed without forming the portion 512b. In this case, the space for forming the second tapered portion 512b can be saved compared to the retaining wall 512 in which the first tapered portion 512a and the second tapered portion 512b are formed. Miniaturization can be achieved.
　また、上記実施形態では、規制壁５１３は、ピストンロッド３０の大径部３２との間のクリアランスｃ２が軸受５５とピストンロッド３０の大径部３２との間のクリアランスｃ１と等しくなるように設けられているが、これに限定されるものではなく、例えば、ピストンロッド３０の大径部３２との間のクリアランスｃ２が軸受５５とピストンロッド３０の大径部３２との間のクリアランスｃ１よりも大きくなるように設けられてもよい。この場合、規制壁５１３とピストンロッド３０の大径部３２とが当接することを防止することができる。 In the above embodiment, the regulation wall 513 is provided so that the clearance c2 between the piston rod 30 and the large diameter portion 32 is equal to the clearance c1 between the bearing 55 and the piston rod 30 large diameter portion 32. For example, the clearance c2 between the large diameter portion 32 of the piston rod 30 is larger than the clearance c1 between the bearing 55 and the large diameter portion 32 of the piston rod 30. It may be provided to be large. In this case, contact between the regulation wall 513 and the large diameter portion 32 of the piston rod 30 can be prevented.
　本願は２０２１年２月１０日に日本国特許庁に出願された特願２０２１－０２００９６に基づく優先権を主張し、この出願の全ての内容は参照により本明細書に組み込まれる。 This application claims priority based on Japanese Patent Application No. 2021-020096 filed with the Japan Patent Office on February 10, 2021, and the entire contents of this application are incorporated herein by reference.

Claims (4)

  1. 　ピストンが設けられたピストンロッドがシリンダチューブ内に往復動可能に設けられた流体圧シリンダであって、
    　前記シリンダチューブの端部開口部を閉塞し、前記ピストンロッドが挿通する挿通孔が形成された閉塞部材と、
    　前記閉塞部材に設けられ、前記ピストンロッドを摺動自在に支持する軸受と、
    　前記閉塞部材と前記ピストンとの間に区画された圧力室と、を備え、
    　前記閉塞部材は、前記挿通孔の内周面に形成され前記軸受が収容される軸受収容溝を有し、
    　前記軸受収容溝は、
    　前記軸受の外周面が当接する溝底部と、
    　前記圧力室側への前記軸受の抜けを規制する抜止壁と、を有し、
    　前記抜止壁は、その高さが前記軸受と前記ピストンロッドとの間のクリアランスよりも大きい流体圧シリンダ。     A fluid pressure cylinder in which a piston rod provided with a piston is reciprocably provided in a cylinder tube,
    a closing member that closes the end opening of the cylinder tube and has an insertion hole through which the piston rod is inserted;
    a bearing provided in the closing member for slidably supporting the piston rod;
    a pressure chamber defined between the closure member and the piston;
    The closing member has a bearing housing groove formed in the inner peripheral surface of the insertion hole and housing the bearing,
    The bearing housing groove is
    a groove bottom with which the outer peripheral surface of the bearing abuts;
    a retaining wall that restricts the bearing from coming off toward the pressure chamber;
    The retaining wall has a height greater than the clearance between the bearing and the piston rod.
  2. 　前記軸受は、圧入によって、前記抜止壁を乗り越えて前記軸受収容溝に収容され、
    　前記抜止壁には、前記軸受を前記溝底部へガイドする第１テーパ部が形成される請求項１に記載の流体圧シリンダ。     The bearing is housed in the bearing housing groove over the retaining wall by press fitting,
    2. The fluid pressure cylinder according to claim 1, wherein the retaining wall is formed with a first tapered portion that guides the bearing to the groove bottom.
  3. 　前記抜止壁には、前記軸受の端面に対向する第２テーパ部が形成され、
    　前記第２テーパ部の傾斜角が前記第１テーパ部の傾斜角よりも大きい請求項２に記載の流体圧シリンダ。     A second tapered portion facing the end surface of the bearing is formed on the retaining wall,
    The fluid pressure cylinder according to claim 2, wherein the inclination angle of the second taper portion is larger than the inclination angle of the first taper portion.
  4. 　前記軸受収容溝は、前記抜止壁に対向し、前記軸受の軸方向の移動を規制する規制壁をさらに有し、
    　前記規制壁は、その高さが前記抜止壁の高さよりも大きい請求項１から３のいずれか１項に記載の流体圧シリンダ。     The bearing receiving groove further has a restricting wall that faces the retaining wall and restricts axial movement of the bearing,
    The fluid pressure cylinder according to any one of claims 1 to 3, wherein the regulating wall has a height greater than the height of the retaining wall.
PCT/JP2022/004181 2021-02-10 2022-02-03 Hydraulic cylinder WO2022172846A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013199950A (en) * 2012-03-23 2013-10-03 Kyb Co Ltd Hydraulic cylinder
JP2019158068A (en) * 2018-03-15 2019-09-19 Ｋｙｂ株式会社 shock absorber

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013199950A (en) * 2012-03-23 2013-10-03 Kyb Co Ltd Hydraulic cylinder
JP2019158068A (en) * 2018-03-15 2019-09-19 Ｋｙｂ株式会社 shock absorber

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