JP2018135946A - Cylinder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder device capable of improving sealability.SOLUTION: The device has: a cylinder body 14 blocked on one end side and opened on the other end side; an annular lid body 112 provided to block an opening 39 on the other end side of the cylinder body 14; a rod 61 inserted in the cylinder body 14 on one end side, and projecting outward from the cylinder body 14 on the other end side through the lid body 112; a cylindrical rod guide 46 provided an inner side than the lid body 112 on the other end side of the cylinder body 14 and slidably guiding the rod 61; and a seal part 131 provided on an inside diameter side of the lid body 112, and coming into slide contact with an outer peripheral side of the rod 61 to seal the rod 61. The seal part 131 is provided with a main lip 141 closer to the rod guide 46 than the lid body 112, and provided with a dust lip 142 closer to the opening 39 of the cylinder body 14 than the lid body 112. A notch part 125 getting larger in proportion to a non-opposite side is provided on the inside diameter side of the lid body 112 and on a side opposed to the rod guide 46.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cylinder device.

  There is a cylinder device having a lid provided so as to close the opening of the outer cylinder and a rod seal that seals between the lid and the piston rod (see, for example, Patent Document 1).

JP 2011-52732 A

  In the cylinder device, there is a demand for improving the sealing performance.

  The present invention provides a cylinder device that can improve sealing performance.

  According to the present invention, a main lip is provided on the rod guide side of the lid body on the seal portion that is provided on the inner diameter side of the lid body and seals the rod by sliding contact with the outer periphery side of the rod, and is more cylindrical than the lid body. A dust strip is provided on the opening side of the body, and a notch that is larger than the non-opposing side is provided on the inner diameter side of the lid on the side facing the rod guide.

  According to the present invention, the sealing performance can be improved.

It is sectional drawing which shows the cylinder apparatus of one Embodiment which concerns on this invention. It is sectional drawing which shows the principal part of the cylinder apparatus of one Embodiment which concerns on this invention. It is a half sectional view showing the seal member of the cylinder device of one embodiment concerning the present invention. It is image data which shows the simulation result (a) of the contact state of the sealing member and piston rod in the cylinder apparatus of one Embodiment concerning this invention, and the same simulation result (b) of a comparative example. It is a diagram which shows the relationship of the contact width of a sublip with respect to the eccentric amount of a piston rod of the cylinder apparatus of one Embodiment which concerns on this invention, and a comparative example. It is a diagram which shows the relationship of the theoretical oil leakage amount with respect to the eccentric amount of the piston rod of the cylinder apparatus of one Embodiment which concerns on this invention, and a comparative example. It is a half sectional view which shows the modification of the sealing member of the cylinder apparatus of one Embodiment which concerns on this invention. It is image data which shows the simulation result of the contact state of the modification of the sealing member in the cylinder apparatus of one Embodiment concerning this invention, and a piston rod.

  A cylinder device according to an embodiment of the present invention will be described below with reference to the drawings. A cylinder device 11 according to the present embodiment shown in FIG. 1 is a shock absorber used in a suspension device for a vehicle such as an automobile or a railway vehicle.

  The cylinder device 11 forms a reservoir chamber 13 between a metal inner cylinder 12 which is a cylindrical cylinder and a diameter larger than the inner cylinder 12 and provided on the outer peripheral side of the inner cylinder 12. And a metal outer cylinder 14 which is a bottomed cylindrical cylinder. That is, the cylinder device 11 is a double cylinder type shock absorber in which the outer cylinder 14 and the inner cylinder 12 constitute the cylinder 15.

  The outer cylinder 14 includes a bottomed cylindrical bottom cover member 21, a cylindrical body member 22, and a cylindrical opening member 23.

  The bottom cover member 21 has a cylindrical portion 31 and a bottom portion 32 that closes one axial end side of the cylindrical portion 31. In the cylindrical portion 31, the bottom lid member 21 is fitted to an inner peripheral portion of one axial end of the body member 22. ing. The bottom cover member 21 is fixed to the body member 22 in a sealed state by welding in a state where the cylindrical portion 31 is fitted to the body member 22. The bottom portion 32 of the bottom lid member 21 is the bottom portion 32 of the outer cylinder 14, and the cylinder portion 31 of the bottom lid member 21 constitutes a part of the cylindrical side wall portion 35 of the outer cylinder 14. The outer cylinder 14 is closed at one end side in the axial direction of the side wall 35 at the bottom 32. An attachment eye 36 is fixed to the bottom lid member 21 on the opposite side of the bottom portion 32 from the cylindrical portion 31 by welding.

  An opening member 23 is fitted to the inner peripheral portion of the end portion of the body member 22 opposite to the bottom cover member 21 in the axial direction. The opening member 23, the body member 22, and the cylindrical portion 31 of the bottom lid member 21 constitute the cylindrical side wall portion 35 of the outer cylinder 14. The opening member 23 has an opening 39 on the end opposite to the bottom lid member 21 in the axial direction, and the opening 39 is an opening 39 of the side wall 35 of the outer cylinder 14. As a result, the outer cylinder 14 is closed at one end in the axial direction at the bottom 32 and is opened at the other end side opposite to the bottom 32 at the opening 39. The opening member 23 includes a fitting portion 41 that is fitted to the inner peripheral portion of the trunk member 22, and a joint portion 42 that has a larger diameter than the fitting portion 41 and protrudes to the opposite side of the bottom portion 32 relative to the trunk member 22. A male screw 43 is formed on the outer peripheral portion of the joint portion 42.

  The inner cylinder 12 has a cylindrical shape. The inner cylinder 12 is engaged with the bottom 32 of the outer cylinder 14 via an annular base valve 45 attached to one end in the axial direction. The inner cylinder 12 is engaged with the opening 39 side opposite to the bottom 32 of the side wall 35 of the outer cylinder 14 through a cylindrical metal rod guide 46 attached to the other end in the axial direction. Are combined.

  The base valve 45 is placed on the bottom portion 32 of the outer cylinder 14 in a state of being fitted and fixed to the inner peripheral portion of one end of the inner cylinder 12. Positioned in the direction. In this state, the base valve 45 is arranged coaxially with the outer cylinder 14 on the bottom 32 side in the axial direction of the inner cylinder 12. The rod guide 46 is fitted to the inner peripheral part of the other end of the inner cylinder 12 and the inner peripheral part of the side wall part 35 of the outer cylinder 14, so that the opposite side of the inner cylinder 12 from the bottom 32 in the axial direction is externally provided. It arranges coaxially with the cylinder 14.

  The cylinder device 11 includes a seal member 51, a friction member 52, an interposition member 53, and a cap 54 in addition to the rod guide 46 described above on the opening 39 side of the outer cylinder 14.

  The seal member 51 is disposed on the opposite side of the bottom portion 32 with respect to the rod guide 46 in the axial direction of the outer cylinder 14, and is fitted to the inner peripheral portion of the side wall 35 of the outer cylinder 14 on the opening 39 side. Yes. The interposition member 53 is disposed on the opposite side of the bottom portion 32 with respect to the seal member 51 in the axial direction of the outer cylinder 14, and is disposed inside the opening 39 of the side wall portion 35 of the outer cylinder 14. The cap 54 is attached to the outer cylinder 14 so as to cover the opening 39 and the interposition member 53 of the outer cylinder 14 on the side opposite to the bottom 32 in the axial direction of the outer cylinder 14. The friction member 52 is disposed on the seal member 51 side in the rod guide 46.

  The rod guide 46, the seal member 51, the friction member 52, the interposition member 53, and the cap 54 are all annular. A metal rod-shaped piston rod 61 (rod) is inserted inside each of the rod guide 46, the seal member 51, the friction member 52, the interposed member 53, and the cap 54. One end of the piston rod 61 is inserted into the inner cylinder 12 in the outer cylinder 14, and the other end of the piston rod 61 passes through the inside of the rod guide 46, the friction member 52, the seal member 51, the interposition member 53 and the cap 54. 14 protrudes to the outside.

  The rod guide 46 supports the piston rod 61 so as to be slidable in the axial direction while restricting its radial movement, and guides the piston rod 61 to slide. The seal member 51 is in contact with the inner peripheral portion of the side wall portion 35 of the outer cylinder 14 at the outer peripheral portion thereof, and is in sliding contact with the outer peripheral portion of the piston rod 61 moving in the axial direction at the inner peripheral portion thereof. And the piston rod 61 are sealed. The friction member 52 slidably contacts the outer peripheral portion of the piston rod 61 at the inner peripheral portion thereof, and causes the piston rod 61 to generate a frictional resistance. The friction member 52 is not intended for sealing. The rod guide 46 and the seal member 51 are fitted on the opening 39 side of the opening member 23.

  The cap 54 includes a cylindrical tubular portion 65 and a perforated disk-shaped inner flange portion 66 that extends radially inward from one axial end of the tubular portion 65. A female screw 67 is formed on the inner peripheral portion of the cylindrical portion 65, and a plurality of through holes 68 penetrating in the axial direction are formed in the inner flange portion 66. The cap 54 is attached to the outer cylinder 14 by the female screw 67 of the cylindrical portion 65 being screwed into the male screw 43 of the opening member 23. The cap 54 attached to the outer cylinder 14 has an inner flange 66 that covers the opening 39 of the opening member 23 on the outer side in the axial direction, and the seal member 51 and the rod guide 46 through the interposition member 53. Pinch.

  Here, as described above, the sealing member 51 is not sandwiched between the rod guide 46 with the cap 54 and the interposition member 53 which are separate from the outer cylinder 14, but the end of the outer cylinder 14 on the opening 39 side. May be bent radially inward to form a locking portion, and the sealing member 51 may be sandwiched between the rod guide 46 by this locking portion.

  An annular piston 70 is slidably fitted in the inner cylinder 12. The piston 70 defines a first chamber 71 and a second chamber 72 in the inner cylinder 12. The first chamber 71 is provided between the piston 70 in the inner cylinder 12 and the rod guide 46, and the second chamber 72 is provided between the piston 70 in the inner cylinder 12 and the base valve 45. The second chamber 72 in the inner cylinder 12 is defined as the reservoir chamber 13 by a base valve 45 provided on one end side of the inner cylinder 12. The first chamber 71 and the second chamber 72 in the inner cylinder 12 are filled with oil as a working fluid, and the reservoir chamber 13 between the inner cylinder 12 and the outer cylinder 14 has a working fluid. The oil liquid and the high-pressure gas are enclosed.

  The piston rod 61 is connected to the piston 70 by the nut 75, so that the piston 70 moves in the axial direction integrally with the piston rod 61. The piston rod 61 has a cylindrical main shaft portion 76 and an attachment shaft portion 77 at an end narrower than the main shaft portion 76, and the attachment shaft portion 77 is disposed in the inner cylinder 12. The piston 70 is attached by a nut 75. The piston rod 61 is slidably inserted inside the rod guide 46, the friction member 52, and the seal member 51 in the main shaft portion 76, and has a gap with respect to the interposition member 53 and the inner flange portion 66 of the cap 54. It is inserted.

  The seal member 51 through which the main shaft portion 76 of the piston rod 61 is inserted closes the space between the outer cylinder 14 and the piston rod 61 so that the oil liquid in the inner cylinder 12 and the oil liquid and gas in the reservoir chamber 13 are separated. It is an oil seal that regulates leakage to the outside.

  The piston 70 is formed with a passage 81 and a passage 82 penetrating in the axial direction. The passages 81 and 82 can communicate the first chamber 71 and the second chamber 72. The piston 70 is provided with an annular disk valve 85 on the side of the opening 39 in the axial direction that can close the passage 81 by contacting the piston 70. The piston 70 is provided with an annular disk valve 86 on the bottom 32 side in the axial direction that can close the passage 82 by contacting the piston 70.

  In the disc valve 85, the piston rod 61 moves to the contraction side to increase the amount of entry into the inner cylinder 12 and the outer cylinder 14, and the piston 70 moves in a direction to narrow the second chamber 72, so that the pressure in the second chamber 72 is increased. When it becomes higher than the pressure in the one chamber 71 by a predetermined value or more, the passage 81 is opened, and a damping force is generated at that time. In the disc valve 86, the piston rod 61 moves to the extending side to increase the amount of protrusion from the inner cylinder 12 and the outer cylinder 14, and the piston 70 moves in a direction to narrow the first chamber 71, so that the pressure in the first chamber 71 is the second. When the pressure is higher than the pressure in the chamber 72 by a predetermined value or more, the passage 82 is opened, and a damping force is generated at that time.

  A locking member 88 is fixed to the main shaft portion 76 of the piston rod 61, and a buffer body 89 made of an annular elastic material is provided opposite to the piston 70 of the locking member 88. The shock absorber 89 relieves the impact by abutting against the rod guide 46 and elastically deforming when the piston rod 61 moves more than a predetermined value to the extension side.

  A passage 91 and a passage 92 are formed in the base valve 45 so as to penetrate in the axial direction. The passages 91 and 92 can communicate with the second chamber 72 and the reservoir chamber 13. In the base valve 45, an annular disk valve 95 that can close the passage 91 by abutting against the base valve 45 is arranged on the side of the bottom 32 in the axial direction, and on the side opposite to the bottom 32 in the axial direction. An annular disk valve 96 that can close the passage 92 by contacting the base valve 45 is disposed.

  The disc valve 95 opens the passage 91 when the piston rod 61 moves to the contraction side and the pressure in the second chamber 72 becomes higher than the pressure in the reservoir chamber 13 by a predetermined value, and generates a damping force at that time. It is a damping valve.

  The disk valve 96 opens the passage 92 when the piston rod 61 moves to the extension side and the piston 70 moves to the first chamber 71 side and the pressure in the second chamber 72 falls below the pressure in the reservoir chamber 13. At this time, the suction valve allows the oil to flow from the reservoir chamber 13 into the second chamber 72 without substantially generating a damping force.

  In the cylinder device 11, the portion outside the cap 54 of the piston rod 61 and the attachment eye 36 are attached to the relative movement portion to be attached. The cylinder device 11 changes the volumes of the first chamber 71 and the second chamber 72 as the piston 70 slides in the inner cylinder 12 of the cylinder 15 in the axial direction integrally with the piston rod 61 by relative movement of the attachment target portion. In this case, a damping force is generated by the flow resistance of the oil generated in the piston 70 and the base valve 45. In the cylinder device 11, for example, the piston rod 61 is connected to the vehicle body side of the vehicle, and the mounting eye 36 is connected to the wheel side of the vehicle to generate a damping force against the movement of the wheel relative to the vehicle body.

  As shown in FIG. 2, the rod guide 46 has a stepped cylindrical shape. A large-diameter portion 101 whose outer peripheral surface is a cylindrical surface is formed on one side in the axial direction, and the outer peripheral surface is large on the other side in the axial direction. A small diameter portion 102 formed of a cylindrical surface having a smaller diameter than the outer peripheral surface of the diameter portion 101 is formed. The rod guide 46 is fitted to the inner peripheral portion of the opening member 23 of the outer cylinder 14 at the large diameter portion 101, and is fitted to the inner peripheral portion of the inner cylinder 12 at the small diameter portion 102.

  An annular annular receiving portion 105 protruding in the axial direction is formed at the end portion of the rod guide 46 on the large diameter portion 101 side in the axial direction. A communication hole 106 that penetrates the large diameter portion 101 in the axial direction is formed in the annular receiving portion 105 at a radially inner position. The communication hole 106 is open to the reservoir chamber 13 between the outer cylinder 14 and the inner cylinder 12 on the side opposite to the annular receiving portion 105 in the axial direction of the rod guide 46.

  The sealing member 51 is an integral body in which a metal annular cover 112 having a higher rigidity is embedded in a sealing body 111 made of rubber having elasticity and sealing properties, specifically, NBR (nitrile rubber). The seal member main body 113, which is a molded product, a metal annular spring 114, and a metal annular spring 115 are provided. The lid body 112 is for maintaining the shape of the seal body 111 and causes the seal member main body 113 to have strength for fixing to the target site. The seal member main body 113 is sandwiched between the rod guide 46, the interposition member 53, and the cap 54 with the radial position of the lid body 112 placed on the annular receiving portion 105 of the rod guide 46.

  In a state of being sandwiched between the rod guide 46, the interposition member 53, and the cap 54, the sealing body 113 has its lid body 112 overlapped with the opening member 23 and the piston rod 61 in the axial direction. Will be placed between. Therefore, the annular lid 112 is provided so as to close the opening 39 shown in FIG. 2 on the other end opposite to the bottom 32 of the outer cylinder 14 whose one end in the axial direction is the bottom 32 shown in FIG. It will be. In this state, the outer cylinder 14 is provided with a rod guide 46 on the inner side of the lid 112 on the opening 39 side at the other end in the axial direction, and the piston rod 61 has one end side in the outer cylinder 14. The other end protrudes from the outer cylinder 14 to the outside through the inside of the lid 112 inserted.

  The lid body 112 has a perforated disk shape, and includes an end surface 121 on the axial rod guide 46 side, an end surface 122 opposite to the axial rod guide 46, an outer diameter surface 123 on the radially outer side, And an inner diameter surface 124 on the radially inner side. The end surfaces 121 and 122 are both annular flat surfaces, and the outer diameter surface 123 and the inner diameter surface 124 are both cylindrical surfaces. The end surface 121 and the end surface 122 are parallel to each other, and the outer diameter surface 123 and the inner diameter surface 124 are arranged coaxially.

  The lid body 112 is chamfered on the inner diameter side on the rod guide 46 side in the axial direction. As a result, a notch 125 is continuously formed on the inner diameter side on the rod guide 46 side in the axial direction. Has been. The notch 125 is notched with the same shape and size regardless of the circumferential position of the lid 112, and has a tapered surface shape. The notch 125 is also arranged coaxially with the outer diameter surface 123 and the inner diameter surface 124.

  As shown in an enlarged view in FIG. 3, the notch 125 has a straight cross-sectional shape including a central axis of the lid 112, and is inclined at 45 degrees with respect to the central axis of the lid 112. Yes. The tapered surface-shaped notch 125 has an axial length that is greater than ½ of the thickness of the lid 112. That is, the cover body 112 is formed with a notch 125 having an axial length exceeding half of its thickness on the inner diameter side on the rod guide 46 side in the axial direction, as shown in FIG. As a result of the tapered surface-shaped notch 125 being formed, the end face 121 on the rod guide 46 side of the lid body 112 has the same outer diameter as the end face 122 opposite to the rod guide 46 and has an inner diameter larger than that of the end face 122. The inner diameter surface 124 is shorter than the outer diameter surface 123 in the axial direction.

  Here, although not shown in the figure, the lid body 112 is slightly chamfered on the inner diameter side opposite to the notch portion 125 in order to suppress burrs during manufacturing and improve handling, etc. As a result, a notch with a tapered surface is formed on the inner diameter side opposite to the notch 125 in the axial direction. However, this notch is very small and smaller than the notch 125. That is, in the lid body 112, the cutout portion 125 on one axial direction has a larger axial length, radial length, and surface area than the cutout portion on the other axial side. As a result, on the inner diameter side of the lid body 112, a cutout portion is provided that has a larger facing side than the non-facing side with respect to the rod guide 46. In addition, similar minute notches are also formed on both sides in the axial direction on the outer diameter side of the lid body 112, but the notch 125 has a shaft even when compared with these notches on the outer diameter side. Both the directional length and the radial length are increased.

  The seal body 111 is baked and bonded to the lid body 112 at all the portions in contact with the lid body 112. 2 and 3 show the seal body 111 in a state before the piston rod 61 is inserted.

  As shown in FIG. 2, the seal body 111 is provided on the inner diameter side of the lid body 112 and seals the piston rod 61 by sliding on the outer circumference side of the piston rod 61, and the axial direction of the lid body 112. An inner side covering portion 132 provided on the rod guide 46 side and in contact with the rod guide 46, an outer diameter side covering portion 133 covering the outer diameter side of the lid body 112, and an axial rod guide 46 of the lid body 112 Has an outer side covering portion 134 that covers the opposite inner diameter side. As shown in FIG. 3, a lid body exposed portion 135 from which the lid body 112 is exposed is formed between the outer side covering portion 134 and the outer diameter side covering portion 133.

  Here, the seal part 131 will be described with the state before the piston rod 61 is inserted. The seal portion 131 includes a cylindrical base portion 140, an annular main lip 141 provided on one end side in the axial direction of the base portion 140, and an annular shape provided on the other end side in the axial direction of the base portion 140. , And an annular sub-lip 143 provided at an intermediate position in the axial direction of the base portion 140.

  The base portion 140 has a cylindrical inner peripheral surface 151 at a portion that does not overlap any of the main lip 141, the dust lip 142, and the sub lip 143 in the axial direction. The dust lip 142 is provided adjacent to the side of the inner peripheral surface 151 opposite to the axial rod guide 46, and the sub lip 143 is provided adjacent to the inner peripheral surface 151 of the axial guide rod 46. The main lip 141 is provided adjacent to the rod guide 46 side in the axial direction of the sub lip 143.

  The dust lip 142 is provided at an end portion of the outer cylinder 14 closer to the opening 39 than the lid body 112 in the base portion 140, and protrudes radially inward from the inner peripheral surface 151 of the base portion 140. As shown in FIG. 3, the dust lip 142 has a tapered inner peripheral surface 152 having a smaller diameter as it is separated from the inner peripheral surface 151 in the axial direction. On the inner peripheral surface 151 side in the axial direction of the inner peripheral surface 152, a plurality of, specifically three, annular muscle portions 153 that protrude radially inward from the inner peripheral surface 152 are provided.

  The sub lip 143 is provided closer to the lid body 112 than the main lip 141 in the base portion 140, and protrudes radially inward from the inner peripheral surface 151 of the base portion 140. The sub lip 143 has a tapered inner peripheral surface 154 that has a smaller diameter as it moves away from the inner peripheral surface 151 in the axial direction, and is located on the opposite side of the inner peripheral surface 151 of the inner peripheral surface 154 from the inner peripheral surface 154 in the axial direction. It has a taper-shaped inner peripheral surface 155 having a larger diameter as it goes away.

  As shown in FIG. 2, the main lip 141 is provided near the end of the base portion 140 closer to the rod guide 46 than the lid body 112, and protrudes radially inward from the inner peripheral surface 151 of the base portion 140. . As shown in FIG. 3, the main lip 141 is located on the opposite side of the inner peripheral surface 155 of the inner peripheral surface 156 and the tapered inner peripheral surface 156 that has a smaller diameter as it moves away from the inner peripheral surface 155 in the axial direction. A taper-shaped inner peripheral surface 157 having a larger diameter as it moves away from the inner peripheral surface 156 in the axial direction.

  The minimum inner diameters of the main lip 141 and the dust lip 142 are substantially the same, and the minimum inner diameter of the sub lip 143 is larger than these.

  The base part 140 has a cylindrical main body part 161 and an annular part 162. The main body 161 extends so as to cross the inner diameter side of the lid body 112 in the axial direction. The annular part 162 protrudes radially outward from the main part 161 over the entire circumference of the main part 161. The annular portion 162 overlaps with the cutout portion 125 of the lid body 112 in both the axial direction and the radial direction, and is in close contact with the entire surface of the cutout portion 125. That is, the annular portion 162 is provided in the base portion 140 so as to fill the portion where the notch 125 is formed in the lid body 112. The notch 125 and the annular portion 162 overlap a part of the sub lip 143 on the inner peripheral surface 151 side with the position in the axial direction.

  As shown in FIG. 2, the seal member main body 113 allows the main shaft portion 76 of the piston rod 61 to be slidably inserted inside the main lip 141 and the dust lip 142 of the seal portion 131. The main lip 141 seals the gap with the main shaft portion 76 of the piston rod 61.

  The inner side covering portion 132 includes a disc-like plate-like covering portion 170, an annular seal ring 171, and an annular check lip 172. The plate-like covering portion 170 extends radially outward from the entire periphery of the base portion 140 of the seal portion 131 and is connected to the entire periphery of the outer diameter side covering portion 133.

  As shown in FIG. 2, the seal ring 171 protrudes from the outer peripheral edge portion of the plate-like covering portion 170 to the side opposite to the axial cover body 112, that is, the rod guide 46 side. The seal ring 171 simultaneously contacts the annular receiving portion 105 of the rod guide 46 and the outer cylinder 14 to seal the gap between the outer cylinder 14 and the rod guide 46.

  The check lip 172 protrudes from the intermediate position in the radial direction of the plate-shaped covering portion 170 to the side opposite to the axial cover body 112, that is, the rod guide 46 side. The check lip 172 has a tapered cylindrical shape having a larger diameter toward the protruding tip side, and is in contact with the annular receiving portion 105 of the large-diameter portion 101 of the rod guide 46 on the radially inner side. The check lip 172 causes the working fluid leaking from the gap between the rod guide 46 and the main shaft portion 76 of the piston rod 61 to flow into the reservoir chamber 13 through the communication hole 106, while reversely regulating the flow of the working fluid in the reverse direction. Functions as a stop valve.

  The spring 114 is attached to the outer peripheral portion of the base portion 140 of the seal portion 131 on the rod guide 46 side in the axial direction and overlaps the main lip 141 with the position in the axial direction. The spring 115 is mounted on the outer peripheral portion of the base portion 140 of the seal portion 131 opposite to the axial rod guide 46, and overlaps the dust strip 142 with the axial position.

  In the seal member 51, the cover body exposed portion 135 and a part on the outer diameter side of the outer cover portion 134 are in contact with the interposition member 53, and the seal ring 171 and the check lip of the plate-like cover portion 170 of the inner cover portion 132. 172 is in contact with the annular receiving portion 105 of the rod guide 46 and is sandwiched between the interposition member 53 and the rod guide 46.

  The cylinder device described in Patent Document 1 has a lid provided so as to close the opening of the outer cylinder, and a rod seal that seals between the lid and the rod, and the lid has a constant inner diameter. It has become. In such a cylinder device, there is a demand for improving the sealing performance.

  On the other hand, in the present embodiment, a notch portion 125 that is notched largely on the side facing the rod guide 46 on the inner diameter side of the lid 112 of the sealing member 51 as compared to the side not facing the rod guide 46. Is provided. For this reason, the volume on the main lip 141 side of the seal portion 131 can be increased by the amount of the annular portion 162 filling the cutout portion 125, and the volume of the portion that is not easily restricted by the lid 112 can be increased. Thereby, the followability on the main lip 141 side of the seal portion 131 with respect to the eccentricity of the piston rod 61 can be enhanced while suppressing a decrease in durability and pressure resistance, and the sealing performance can be enhanced.

  In particular, since the seal portion 131 is provided with the sub lip 143 on the lid 112 side of the main lip 141, the oil film on the surface of the piston rod 61 that can be collected by the sub lip 143 during the extension stroke of the piston rod 61 becomes thicker. Sealability can be improved.

  FIG. 4 shows a simulation result of the contact state between the seal member and the piston rod. As shown in FIG. 4A, the contact width W1 between the piston rod 61 and the sub lip 143 when the gas pressure is applied in the embodiment in which the lid body 112 has the notch 125 is the notch shown in FIG. Compared to the contact width W0 of the comparative example using the conventional lid body without the portion 125, W1> W0, which becomes wider. In the embodiment, the contact angle α1 on the atmosphere side between the piston rod 61 and the sub lip 143 when subjected to gas pressure is smaller than α1 <α0 compared to the contact angle α0 of the comparative example. As a result, the oil film on the surface of the piston rod 61 that can be recovered by the sub lip 143 becomes thick, and the sealing performance can be improved.

  Further, the sealing performance of the sealing member 51 was evaluated based on the fluid lubrication inverse theory from the surface pressure distribution obtained by using the finite element method. The contact pressure on the first chamber 71 side of the surface pressure distribution during the expansion stroke of the piston rod 61 is drawn from the calculated surface pressure distribution to 0 MPa and the contact pressure on the atmosphere side during the contraction stroke is drawn to 0 MPa. As the surface pressure gradient, a theoretical oil leakage amount was calculated when the piston rod 61 was slid 500 times with a speed ratio of 10: 1 during the expansion stroke and the contraction stroke.

  FIG. 5 shows the relationship of the contact width of the sub lip to the piston rod with respect to the eccentric amount of the piston rod. FIG. 6 shows the relationship between the theoretical oil leakage amount and the eccentric amount of the piston rod. 5 and 6, the embodiment in which the lid body 112 has the notch 125 is shown in FIG. 5 and FIG. 6, and the piston rod as shown in FIG. It can be seen that the contact width of the sub lip to the piston rod is wide regardless of the amount of eccentricity, and as shown in FIG. 6, the theoretical oil leakage amount can be reduced to about 1/5 regardless of the amount of eccentricity of the piston rod. Thereby, the seal member 51 of the embodiment can improve the eccentricity followability and sealing performance of the piston rod 61.

  Further, since the notch 125 is formed on the main lip 141 side in the axial direction of the lid 112, the influence on the elastic deformation amount of the dust lip 142 due to the formation of the notch 125 can be suppressed. Therefore, dust penetration resistance can be maintained.

  Here, the shape of the notch 125 of the lid 112 is not limited to the above, and the volume of the seal part 131 on the main lip 141 side can be increased by the amount of the annular part 162 filling the notch 125. It suffices if the volume of the portion that is not easily restricted by the lid 112 can be increased. For example, it is good also as a shape of the modification shown in FIG. That is, the inner diameter side of the lid 112 in the axial direction of the rod guide 46 (the lower side in FIG. 7) is rounded to form a curved notch on the inner diameter side of the lid 112 in the axial direction of the rod guide 46. The portion 125A may be formed continuously over the entire circumference. This notch 125A is also cut out in the same shape and size regardless of the circumferential position, and is arranged coaxially with the outer diameter surface 123 and the inner diameter surface 124. Further, the shape of the annular portion 162 is not limited to the tapered cross section as shown in FIG. 3 or the shape shown in FIG. 7. For example, the cutout portion 125 of the lid 112 may have a rectangular cross section.

  The notch 125A has a cross-sectional shape in a plane including the central axis that is an outwardly convex arc shape, and the length in the axial direction of the lid body 112 is less than ½ of the thickness of the lid body 112. It is larger than the cutout portion on the inner diameter side opposite to the cutout portion 125A in the axial direction. The annular portion 162A of the base portion 140 of the seal body 111 that is in close contact with the entire surface of the cutout portion 125A so as to fill the cutout portion 125A also overlaps with the cutout portion 125A of the lid body 112 in both the axial direction and the radial direction. A part of the sub lip 143 on the inner peripheral surface 151 side overlaps the position in the axial direction.

  Also in such a modified example, the simulation result of the contact state between the seal member and the piston rod is as shown in FIG. 8, and the gas pressure is received in the modified example in which the lid body 112 has a cutout portion 125A having a curved cross section. The contact width W2 between the piston rod 61 and the sub lip 143 at this time is W2> W0 as compared with the contact width W0 of the comparative example using the conventional lid body without the notch 125 shown in FIG. And become wider. Further, the contact angle α2 on the atmosphere side between the piston rod 61 and the sub lip 143 when subjected to gas pressure in the modification is smaller than α2 <α0 compared to the contact angle α0 of the comparative example. Therefore, according to the modification, the same effect as that in the case where the lid body 112 is provided with the notch 125 having a linear cross section can be obtained.

  In the above embodiment, if the sealing body 111 is made of rubber, for example, NR (natural rubber), IR (synthetic natural rubber), SBR (styrene butadiene rubber), BR (butadiene) other than NBR (nitrile rubber). Rubber), CR (chloroprene rubber), IIR (butyl rubber), EPDM (ethylene propylene rubber), CSM (chlorosulfonated polyethylene rubber), ACM (acrylic rubber), U (urethane rubber), H-NBR (hydrogenated nitrile rubber) ), VMQ (silicone rubber), FVMQ (fluorosilicone rubber), FKM (fluororubber), a plurality of selected mixtures of these rubbers, etc., forming an organic material that is elastically deformed by the gas pressure enclosed in the cylinder device 11 Can be used as a material.

  In the first aspect of the above embodiment, a cylindrical body whose one end side is closed and the other end side is opened, an annular lid provided so as to close an opening on the other end side of the cylindrical body, A rod that is inserted into a cylinder and passes through the lid body, the other end projecting outward from the cylinder body, and provided on the inner side of the lid body on the other end side of the cylinder body, can slide the rod A cylindrical rod guide that guides the rod, and a seal portion that is provided on the inner diameter side of the lid body and seals the rod by sliding in contact with the outer peripheral side of the rod. A cylinder device in which a main lip is provided on the rod guide side and a dust lip is provided on the opening side of the cylindrical body with respect to the lid body, wherein the rod guide is disposed on the inner diameter side of the lid body. Notch that is larger on the opposite side than the non-opposing side And it is provided. Thereby, sealing performance can be improved.

  Moreover, a 2nd aspect is a 1st aspect. WHEREIN: The said seal part is provided with the sub lip at the said cover body side rather than the said main lip. As a result, the oil film on the surface of the piston rod that can be recovered by the sub lip becomes thick, and the sealing performance can be improved.

11 Cylinder device 14 Outer cylinder (cylinder)
39 Opening 46 Rod guide 61 Piston rod (rod)
112 Lid 125, 125A Notch 131 Seal 141 141 Main lip 142 Dustrip 143 Sub lip

Claims (2)

A cylinder with one end closed and the other end opened;
An annular lid provided to close the opening on the other end of the cylindrical body;
A rod whose one end side is inserted into the cylinder body, passes through the lid body, and the other end side protrudes from the cylinder body,
A cylindrical rod guide provided on the inner side of the lid on the other end side of the cylindrical body to guide the rod slidably;
A seal portion that is provided on the inner diameter side of the lid body and seals the rod by sliding on the outer periphery side of the rod;
The seal portion is a cylinder device in which a main lip is provided on the rod guide side of the lid body, and a dust lip is provided on the opening side of the cylindrical body of the lid body,
A cylinder device characterized in that a cutout portion which is larger than the non-opposing side is provided on the inner diameter side of the lid on the side facing the rod guide.   The cylinder device according to claim 1, wherein the seal portion is provided with a sub lip on the lid side of the main lip.