JP2012031899A - Cylinder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder device capable of enhancing assembling operability.SOLUTION: In the cylinder device including a cylinder 12 in which liquid is encapsulated, an outer cylinder 13 covering the cylinder 12, a rod 15 inserted in the cylinder 12, a rod guide 24 provided at end parts of the cylinder 12 and the outer cylinder 13 and guiding the rod 15 and a seal ring 29 sealing a gap between the rod guide 24 and the outer cylinder 13, the rod guide 24 has a fitted cylindrical surface 52 fitted to the outer cylinder 13, a tapered surface 54 on which the seal ring 29 is disposed together with the outer cylinder 13 and a temporarily holding cylindrical surface 53 having a diameter smaller than that of the fitted cylindrical surface 52 and capable of temporarily holding the seal ring 29 before fitting to the outer cylinder 13.

Description

  The present invention relates to a cylinder device.

  Some cylinder devices are provided with a seal ring between an outer cylinder and a rod guide (see, for example, Patent Document 1).

JP 2009-222128 A

  In the above cylinder device, the seal ring is integrated with the other ring member, so that it can be easily assembled to the outer cylinder. Unlike this, in the case of a structure in which the seal ring is assembled alone, there is a problem that the workability of the assembly is not good.

  Therefore, an object of this invention is to provide the cylinder apparatus which can improve the workability | operativity of an assembly | attachment.

  In order to achieve the above object, the present invention provides a rod guide having a fitting cylindrical surface that fits into an outer cylinder, a tapered surface in which a seal ring is disposed between the outer cylinder, and the fitting cylindrical surface. A temporary holding cylindrical surface having a smaller diameter and capable of temporarily holding the seal ring before fitting into the outer cylinder.

  According to the present invention, the workability of assembly can be improved.

1 is an overall cross-sectional view showing a hydraulic shock absorber that is an embodiment of a cylinder device according to the present invention. It is a partial expanded sectional view in the middle of an assembly showing the important section of the hydraulic shock absorber which is one embodiment of the cylinder device concerning the present invention. It is a partial expanded sectional view in the middle of an assembly showing the important section of the hydraulic shock absorber which is one embodiment of the cylinder device concerning the present invention.

  A hydraulic shock absorber which is an embodiment of a cylinder device according to the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the hydraulic shock absorber according to the present embodiment is of a double cylinder type, and is used for, for example, a suspension device of an automobile. The hydraulic shock absorber is disposed on a cylinder 12 in which oil liquid (liquid) is sealed, an outer cylinder 13 having a larger diameter than the cylinder 12 and coaxially arranged with the cylinder 12 to cover the cylinder 12, and a central axis of the cylinder 12. At the same time, one end is inserted into the cylinder 12 and the other end is projected to the outside from the cylinder 12 and the outer cylinder 13. The rod 15 is attached to the rod 15 and is slidably fitted into the cylinder 12. It has a piston 18 that defines two oil chambers 16 and 17 inside.

  The hydraulic shock absorber includes a base cap 20 that closes the end of the outer cylinder 13 opposite to the protruding side of the rod 15, a mounting eye 21 that is fixed to the outside of the base cap 20, and an inner side of the base cap 20. And a base valve 22 attached to the end of the cylinder 12 opposite to the protruding side of the rod 15.

  Further, the hydraulic shock absorber is inserted to guide the rod 15 and is fitted to the protruding ends of the rods 15 of both the cylinder 12 and the outer cylinder 13, and is disposed outside the rod guide 24. A packing cap 25 that is locked to the end of the outer cylinder 13, a packing 26 that is disposed inside the packing cap 25 and closes the gap between the rod 15 and the packing cap 25, and the rod guide 24 side of the packing 26. A packing retainer 27 that contacts the packing retainer 27, a packing spring 28 that is interposed between the packing retainer 27 and the rod guide 24 and presses the packing retainer 27 in the direction of the packing 26, a packing cap 25, the rod guide 24, and the outer cylinder 13. And a seal ring 29 that seals these gaps.

  The outer cylinder 13 has a substantially cylindrical shape including a cylindrical outer cylinder main portion 31 and a locking portion 32 protruding radially inward from an end portion of the outer cylinder main portion 31 on the protruding side of the rod 15. Yes. The locking portion 32 is formed by a so-called curl method, and is formed by plastically deforming an end portion of a cylindrical material radially inward.

  The base valve 22 controls communication and blocking between the reservoir chamber 35 between the cylinder 12 and the outer cylinder 13 and the oil chamber 17, and the pressure on the oil chamber 17 side is higher than the pressure on the reservoir chamber 35 side. In this state, the flow of the oil liquid from the oil chamber 17 to the reservoir chamber 35 side is allowed to generate a damping force, and the pressure on the oil chamber 17 side is lower than the pressure on the reservoir chamber 35 side. The flow of the oil liquid to the oil chamber 17 side is permitted.

  In the state where the pressure on the oil chamber 17 side is higher than the pressure on the oil chamber 16 side, the piston 18 allows a flow of oil from the oil chamber 17 to the oil chamber 16 side and generates a damping force. A damping force generating mechanism 36 that generates a damping force by allowing the flow of the oil liquid from the oil chamber 16 to the oil chamber 17 side in a state where the pressure on the side is lower than the pressure on the oil chamber 16 side is provided.

  When the rod 15 moves to the extension side and the amount of protrusion from the cylinder 12 increases, the corresponding amount of oil liquid flows from the reservoir chamber 35 to the oil chamber 17 via the base valve 22, and conversely the rod 15 When the oil is moved to the contraction side and the amount of insertion into the cylinder 12 is increased, the corresponding oil liquid flows from the oil chamber 17 to the reservoir chamber 35 via the base valve 22. In order to cope with such supply and discharge of the oil liquid, the reservoir chamber 35 stores the oil liquid on the base cap 20 side which is the lower part, and the oil liquid is stored on the rod guide 24 side which is the upper side of the oil liquid. Gas that absorbs the change in volume is enclosed.

  FIG. 2 shows a state during the assembly of the hydraulic shock absorber. In FIG. 2, the outer cylinder 13 shown in FIG. 1 processes the outer cylinder main portion 31 and the locking portion 32 shown in FIG. And a previous pre-processing state portion 32 '(same in FIG. 3). The pre-processing state portion 32 ′ has a cylindrical shape with the same inner diameter and outer diameter as the pre-processing state portion 32 ′ side portion of the outer cylinder main portion 31.

  As shown in FIG. 2, the rod guide 24 has a large-diameter outer diameter portion 40 formed on one side in the axial direction, and a small-diameter outer diameter portion 41 smaller in diameter than the large-diameter outer diameter portion 40 formed on the other side in the axial direction. It has a substantially stepped cylindrical shape. The rod guide 24 is fitted to the inner peripheral part of the outer cylinder main part 31 of the outer cylinder 13 at the large-diameter outer diameter part 40, and is fitted to the inner peripheral part of the cylinder 12 at the small-diameter outer diameter part 41. In the center of the rod guide 24 in the radial direction, an insertion hole 42 through which the rod 15 is inserted is formed penetrating along the axial direction.

  On the outer end side in the axial direction of the rod guide 24, an annular groove 44 having a diameter larger than that of the insertion hole 42 is formed at an intermediate position in the radial direction. By forming the annular groove 44, an inner annular convex portion 45 projecting in the axial direction between the insertion hole 42 and the annular groove 44 is formed on the outer end side in the axial direction of the rod guide 24. The outer annular convex portions 46 projecting in the axial direction are formed on the outer sides in the radial direction.

  Further, the rod guide 24 is formed with a communication hole 48 penetrating along the axial direction at the position of the outer annular convex portion 46, and the outer annular convex portion 46 has the communication hole 48 on the annular groove 44 side. A passage groove 49 to be opened is formed. The communication hole 48 communicates with the reservoir chamber 35 between the outer cylinder 13 and the cylinder 12. A cylindrical collar 50 made of a fluororesin is fitted in the insertion hole 42 of the rod guide 24, and the rod 15 is inserted into the collar 50 so as to be in sliding contact. Due to the sliding of the rod 15, the oil liquid in the cylinder 12 leaks through the gap between the collar 50 and the rod 15, and this oil liquid passes through the annular groove 44 through the passage groove 49 and the communication hole 48. It is returned to the reservoir chamber 35.

  In the present embodiment, as shown in FIG. 3, the outer peripheral surface of the large-diameter outer diameter portion 40 of the rod guide 24 is on the small-diameter outer diameter portion 41 side in the axial direction and is fitted to the outer cylinder 13. Of the combined cylindrical surface 52, the temporary holding cylindrical surface 53 on the opposite side of the small-diameter outer diameter portion 41 in the axial direction of the fitting cylindrical surface 52 and having a smaller diameter than the fitting cylindrical surface 52, It has a tapered surface 54 that is on the opposite side of the fitting cylindrical surface 52 in the axial direction and has a smaller diameter as the distance from the temporary holding cylindrical surface 53 increases.

  The temporary holding cylindrical surface 53 described above can temporarily hold the seal ring 29 alone before the rod guide 24 is fitted to the outer cylinder 13. Here, the seal ring 29 is a square ring whose one-side cross section along the radial direction forms a rectangular shape, and its axial thickness is constant and the cross-sectional width is also constant.

  Such a seal ring 29 is slightly expanded in diameter and fitted to the temporary holding cylindrical surface 53 so as to be temporarily held by the rod guide 24. At that time, the seal ring 29 is in close contact with the cylindrical temporary holding cylindrical surface 53 on the cylindrical inner peripheral surface. The axial length of the temporary holding cylindrical surface 53 is a length that allows the seal ring 29 to be held in a fitted state, and is set to a length equivalent to the axial thickness of the seal ring 29, for example. The radial difference between the temporary holding cylindrical surface 53 and the fitting cylindrical surface 52 is smaller than the cross-sectional width of the seal ring 29 held by the temporary holding cylindrical surface 53, and is held by the temporary holding cylindrical surface 53. The outer diameter of the seal ring 29 in the finished state is larger than the fitting cylindrical surface 52 and larger than the inner diameter of the pre-processing state portion 32 ′. The tapered surface 54 has a minimum diameter smaller than the inner diameter of the seal ring 29 in the natural state. In addition, the outer diameter of the natural seal ring 29 is slightly smaller than the inner diameter of the pre-processing state portion 32 '.

  Then, the seal ring 29 is temporarily held on the temporary holding cylindrical surface 53 of the rod guide 24 before fitting to the outer cylinder 13, and in this state, the rod guide 24 is held in the pre-processing state portion 32 of the outer cylinder 13. 'And the outer cylinder main part 31 are fitted. Then, the rod guide 24 is first fitted into the pre-processed state portion 32 ′ of the outer cylinder 13 on the fitting cylindrical surface 52 as shown in FIG. It enters into the outer cylinder 13. When the temporary holding cylindrical surface 53 enters the outer cylinder 13, the seal ring 29 comes into contact with the end surface of the pre-processing state portion 32 ′ and stops at that position, so that the temporary holding cylindrical surface 53 comes out of the temporary holding cylindrical surface 53. The seal ring 29 is reduced in diameter while moving toward the tapered surface 54 as indicated by an arrow X in FIG. 3, and enters the inside of the outer cylinder 13 as shown in FIG. Thereby, the seal ring 29 is disposed concentrically (that is, centered) above the annular gap 55 between the tapered surface 54 and the outer cylinder 13. The rod guide 24 is finally fitted to a position where the small-diameter outer diameter portion 41 is disposed in the cylinder 12 and the large-diameter outer diameter portion 40 contacts the cylinder 12 and stops.

  In this state, when the packing cap 25 is inserted into the outer cylinder 13 to a position where it abuts against the rod guide 24, the packing cap 25 pushes the seal ring 29 into the gap 55 between the tapered surface 54 and the outer cylinder 13. In this state, when the pre-processing state portion 32 ′ of the outer cylinder 13 is plastically deformed to form the locking portion 32, the packing cap 25 is sandwiched and fixed between the locking portion 32 and the rod guide 24. Then, the seal ring 29 is disposed in the gap 55 between the tapered surface 54 of the rod guide 24 and the outer cylinder main portion 31 of the outer cylinder 13, and the seal ring 29 is elastically deformed so as to fill the gap 55. Thus, the taper surface 54 of the rod guide 24 and the outer cylinder 13 are brought into close contact with each other to seal the gap therebetween. As a result, the outer cylinder 13 side of the reservoir chamber 35 on the rod guide 24 side is sealed.

  According to the hydraulic shock absorber of the present embodiment described above, the rod guide 24 has a smaller diameter than the fitting cylindrical surface 52 fitted to the outer cylinder 12 and the seal ring 29 before fitting to the outer cylinder 12. Since the temporary holding cylindrical surface 53 capable of temporarily holding the seal ring 29 is provided between the tapered surface 54 holding the seal ring 29 between the outer cylinder 13 and the fitting cylindrical surface 52, the seal ring 29 is temporarily held. When the rod guide 24 temporarily held on the cylindrical surface 53 is fitted to the outer cylinder 12, the seal ring 29 can be appropriately disposed in the gap 55 between the tapered surface 54 and the outer cylinder 13. Therefore, even if the seal ring 29 has a structure that is assembled alone, the workability of the assembly can be improved. That is, when the seal ring 29 is separately arranged from the outside aiming at the gap 55 between the tapered surface 54 and the outer cylinder 13, the seal ring 29 is manually arranged in the gap 55 over the entire circumference. The work becomes complicated, but the assembling workability can be improved as compared with this.

  In the above embodiment, the case where the seal ring 29 is a square ring has been described as an example. However, the present invention is also applicable to an O-ring having a circular one-side cross section.

11 Hydraulic shock absorber (cylinder device)
12 cylinder 13 outer cylinder 15 rod 24 rod guide 29 seal ring 52 fitting cylindrical surface 53 temporary holding cylindrical surface 54 taper surface

Claims (1)

A cylinder filled with liquid;
An outer cylinder covering the cylinder;
A rod inserted into the cylinder;
A rod guide that is provided at an end of the cylinder and the outer cylinder and guides the rod;
A cylinder device comprising a seal ring that seals a gap between the rod guide and the outer cylinder,
The rod guide has a fitting cylindrical surface to be fitted to the outer cylinder, a tapered surface on which the seal ring is disposed between the outer cylinder, and a smaller diameter than the fitting cylindrical surface to the outer cylinder. And a temporary holding cylindrical surface capable of temporarily holding the seal ring before fitting.

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