JP2010255641A - Oil seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock-absorber oil seal including a metal ring and a seal lip, for meeting a need for reducing the weight of components by reducing the weight of the metal ring without reducing the strength of the metal ring. <P>SOLUTION: The shock-absorber oil seal includes the metal ring caulked and fixed with the casing of a shock absorber, and the seal lip mounted on the metal ring and slidably put in close contact with the peripheral face of a rod. The metal ring has a hole portion for reducing the weight. The hole portion is a through-hole opened to both faces of the metal ring in the thickness direction and closed with a hard-material cover member laid on the metal ring to secure the pressure resistance of the through-hole. The weight of the cover member is set to be smaller than a decrement in the weight of the metal ring due to the formation of the through-hole. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an oil seal that is a kind of sealing device, and more particularly to an oil seal for a shock absorber.

  Conventionally, as shown in FIG. 5, a metal ring (also referred to as a washer ring) 52 that is caulked and fixed by a casing 51 of a shock absorber is provided, and the metal ring 52 is slidably in close contact with the peripheral surface of the rod 53. An oil seal for a shock absorber is known which is provided with a seal lip 54 and seals the pressure oil inside the absorber (see Patent Document 1).

  By the way, in recent years, an absorber manufacturer is considering reducing the weight of the absorber product, and the oil seal for the absorber, which is a component thereof, is also required to be reduced in weight.

  However, the above-described absorber oil seal requires a high strength metal ring 52 because it is used under high pressure and receives a large caulking load during assembly. A metal ring 52 having a large thickness (approx. 3.2 mm) is used (SAPH, SPFH).

  As described above, the metal ring 52 having a high strength material and a large thickness occupies 90% or more of the weight of the oil seal for the absorber. For this reason, it is not possible to reduce the thickness of the metal ring 52 or change its material to a lightweight metal because the strength of the metal ring 52 is reduced.

Japanese Patent Laid-Open No. 11-101289

  In view of the above points, the present invention can reduce the weight of a metal ring without reducing the strength of the metal ring in an oil seal for a shock absorber having a metal ring and a seal lip. An object of the present invention is to provide an oil seal capable of meeting the requirements of the above.

  In order to achieve the above object, an oil seal according to claim 1 of the present invention comprises a metal ring that is caulked and fixed by a casing of a shock absorber, a metal ring that is attached to the metal ring and that is slidably in close contact with the circumferential surface of the rod. In the oil seal for a shock absorber having a seal lip, the metal ring has a hole for reducing its weight, and the hole consists of through holes that open on both sides in the thickness direction of the metal ring, A lid member made of a hard material is placed on the metal ring to close the through hole so as to ensure pressure resistance in the through hole, and the weight of the lid member is light weight due to the formation of the through hole in the metal ring. It is characterized by being set smaller than the fraction.

  According to a second aspect of the present invention, there is provided an oil seal comprising: a metal ring that is caulked and fixed by a casing of a shock absorber; and a seal lip that is attached to the metal ring and is slidably in close contact with the peripheral surface of the rod. In the shock absorber oil seal, the metal ring has a hole for reducing its weight, and the hole is formed of a bottomed counterbored hole that opens on one surface in the thickness direction of the metal ring. Features.

  According to a third aspect of the present invention, there is provided an oil seal comprising: a metal ring that is caulked and fixed by a shock absorber casing; and a seal lip that is attached to the metal ring and is slidably in close contact with the peripheral surface of the rod. In the oil seal for shock absorbers, the metal ring has a hole for reducing the weight thereof, and the hole has a material for the metal ring at an outer peripheral edge and an inner peripheral edge of the annular flat portion, respectively. It is formed by pressing into a shape in which the cylindrical portion is integrally formed.

  Even if a metal ring is made of a high-strength material with a large thickness as in the prior art, if a hole is provided in the metal ring, the volume of the metal ring is reduced, and thus the metal ring is not reduced in strength. It is possible to reduce the weight of the ring. Therefore, the present invention is characterized in that a hole is provided in the metal ring.

  Although it is conceivable to provide through holes that open on both sides of the metal ring in the thickness direction, it is necessary to close the through holes by some means in order to ensure sealing properties when providing through holes in the metal ring. As a closing means, it is conceivable to fill the through hole with a rubber-like elastic body integral with the seal lip.

  However, when the through hole is closed with a rubber-like elastic body in this way, an extremely high hydraulic pressure acts on the rubber-like elastic body when the absorber is operated. There is a risk of damage.

  Therefore, in the present invention, pressure resistance is ensured by the following structure.

  That is, a lid member made of hard material is placed on the metal ring to ensure pressure resistance in the through hole, and the through hole is closed with the lid member made of hard material. The lid member made of hard material is higher in pressure resistance than the rubber-like elastic body in terms of the material. Specific examples of the lid member include a metal washer.

  When the lid member made of hard material is overlapped with the metal ring in this way, the weight of the oil seal can be reduced if the weight of the lid member is larger than the weight reduction due to the formation of the through hole in the metal ring. It cannot be realized. Therefore, it is necessary to set the weight of the lid member to be smaller than the weight reduction due to formation of the through hole in the metal ring.

  Further, the hole provided in the metal ring may be a bottomed counterbored hole that opens on one surface in the thickness direction of the metal ring, and in this case, the hole is bottomed and is a leading edge. The pressure resistance is ensured without overlapping the lid member. Further, since it is not necessary to overlap the lid member, the weight reduction due to the formation of the counterbore hole immediately leads to the weight reduction of the oil seal.

  In addition, the reason for using a high-strength material with a large thickness as in the above prior art as the metal ring is that high strength is required for the metal ring, but even when using a small thickness, If this is a three-dimensional structure, the required high strength can be ensured.

  Therefore, in the present invention, the metal ring is three-dimensionalized by pressing the material of the metal ring into a shape in which the cylindrical portion is integrally formed at the outer peripheral end portion and the inner peripheral end portion of the annular flat surface portion, and the inside of the three-dimensional shape is formed. It was decided to make the metal ring lighter by making a hole.

  Therefore, according to the present invention, when the metal ring is provided with a through hole and the lid member is overlapped (Claim 1), when the counterbore hole is provided on the metal ring (Claim 2), the metal ring is three-dimensionalized. (Claim 3) In any case, the weight of the metal ring can be reduced without reducing the strength of the metal ring, so that it can meet the recent demand for weight reduction of parts. An oil seal can be provided.

(A) is principal part sectional drawing of the oil seal which concerns on 1st Example of this invention, (B) is a disassembled perspective view of the metal ring and cover member in the oil seal (A) is principal part sectional drawing of the oil seal which concerns on 2nd Example of this invention, (B) is principal part sectional drawing of the oil seal which concerns on 3rd Example of this invention. Sectional drawing of the principal part of the oil seal which concerns on 4th Example of this invention. Sectional drawing of the principal part of the oil seal which concerns on 5th Example of this invention. Cross section of the main part of the oil seal according to the conventional example

  The present invention includes the following embodiments.

(1-1) As for the metal ring of the oil seal for the absorber, there is a demand for weight reduction in recent years because the strength of the caulking portion with respect to the pressure during caulking and the pressure resistance during operation are required. As a countermeasure, it may be possible to reduce the weight while maintaining strength by punching the metal ring at several points on the circumference and closing it with rubber, but in this case, the rubber part deforms due to the internal hydraulic pressure during operation, There is a concern that the sealing function (pressure resistance) may not be satisfied.
(1-2) Therefore, in order to suppress deformation of the rubber part, a thin washer for pressure resistance is placed on the metal ring. In order to prevent misalignment of the washer, the washer has an L-shaped cross section (when rubber lip vulcanized). Also, a counterbore hole is provided in the metal ring to eliminate the washer.
(1-3) By making a hole as described above, it is possible to reduce the weight without changing the thickness of the crimped portion, and it is possible to ensure the same strength as before. Further, by installing the washer and making the hole counterbored, it is possible to suppress deformation of the rubber part that becomes a problem when a hole is made in the metal ring.

(2-1) About the oil seal for the absorber, at present, the metal ring is made of a high-strength material (plate thickness: 3.2 mm) so as to withstand the caulking stress during assembly and the internal hydraulic pressure during use.
(2-2) To reduce the weight of the oil seal, a hole for reducing the weight is provided in the metal ring. In this case, the lightweight hole is set each time depending on the seal size and use conditions. However, in this case, since the internal oil pressure cannot be maintained if the hole is closed with rubber, there is a concern about deformation of the rubber part due to pressure, and the sealing function is NG.
(2-3) Therefore, in the present plan, this is countered by stacking a thin plate lid (such as an SPCC washer) on the lighter metal ring (perforated). The weight of the lightweight metal ring (perforated) + lid is set so as not to exceed the weight of the metal ring (no hole).
(2-4) Since the lid may move with respect to the weight-reduced metal ring during vulcanization, the position is stabilized by using the lid as an L-shaped ring for positioning. The lid may be rotated to the back (back side) of the lightweight metal ring by bending it twice at a right angle.
(2-5) Instead of the through hole, a counterbore hole may be provided. In this case, since a lid is not required, the effect of weight reduction is great.

(3) To reduce the weight of the oil seal, press the metal ring with a small plate thickness into a U-shaped cross section to reduce the amount of metal ring used. When assembling the seal (when caulking the outer cylinder), the inner ring side of the metal ring (U-shaped cross section) is guided by the assembling seal retainer, and the outer cylinder is caulked while suppressing caulking deformation of the metal ring. By suppressing the caulking deformation of the metal ring with the assembly seal holder, the thickness of the metal ring can be set thin, and the product weight can be reduced (weight reduction). The U-shaped ring may be either forged or cast.

  Next, embodiments of the present invention will be described with reference to the drawings.

First embodiment ...
FIG. 1 shows an oil seal for a shock absorber according to a first embodiment of the present invention, and the oil seal is configured as follows.

  That is, first, a metal ring 11 is provided between an end surface portion of a rod guide 41 which is a casing in a shock absorber and a caulking portion 42a at the tip of an outer cylinder 42, and a lid member 21 made of hard material is stacked on the metal ring 11. In addition, a rubber-like elastic body 31 is attached to the metal ring 11 and the lid member 21. On the end surface portion of the rod guide 41, an annular caulking projection 41a is provided for strongly pressing the oil seal during caulking.

  The metal ring 11 is formed in an annular shape with a high-strength metal (for example, SAPH, SPFH) and has a large thickness (for example, a thickness of about 3.2 mm), but the hole 12 is formed to reduce the weight. The holes 12 are formed by through holes that open on both end surfaces of the metal ring 11 in the thickness direction. In addition, the hole portion 12 is disposed approximately at the center in the radial direction of the metal ring 11 and a plurality (six locations in the drawing) are provided on the circumference of the metal ring 11.

  The lid member 21 made of hard material is formed in an annular shape like the metal ring 11 with a predetermined metal (for example, SPCC), and is superposed on the end face inside the absorber in the metal ring 11 without adhesion. The inner diameter and the outer diameter dimension of the lid member 21 are set to be the same as the inner diameter and the outer diameter dimension of the metal ring 11, respectively, but the dimensions are not particularly limited as long as all the holes 12 can be closed. In order to reduce the weight of the oil seal as a whole, the weight of the lid member 21 is set to be smaller than the weight of the weight reduction due to the formation of the hole 12 in the metal ring 11.

  The rubber-like elastic body 31 also has an annular shape, and is vulcanized and bonded to the metal ring 11 and the lid member 21 at the same time as the molding, and is slidably in close contact with the peripheral surface of the rod 43 and mainly inside the absorber. A seal lip 32 that seals pressure oil, a dust lip 33 that is slidably in close contact with the peripheral surface of the rod 43 and mainly seals dust or the like outside the absorber, and inner peripheral surfaces of the lid member 21 and the metal ring 11 An inner peripherally attached portion 34 attached to the outer peripheral surface of the metal ring 11, an outer attached portion 35 attached to a part of the outer end face of the metal ring 11, and an inner attached portion 36 attached to the inner end face of the lid member 21. The outer peripheral adherence portion 37 attached to the outer peripheral surfaces of the lid member 21 and the metal ring 11, the intermediate lip 38 in close contact with the end surface portion of the rod guide 41, the outer peripheral surface of the protrusion 41a of the rod guide 41 and the outer cylinder 42. An outer peripheral lip 39 closely contacting the inner peripheral surface of It is molded in one piece. Therefore, the lid member 21 is completely covered with the rubber-like elastic body 31.

  In the oil seal having the above-described configuration, the metal ring 11 is provided with the hole portion 12 made of a through hole, and the weight of the lid member 21 that is overlapped to close the hole portion 12 is light and light due to the formation of the hole portion 12 in the metal ring 11. Since it is set to be smaller than the chemical component, the entire oil seal is reduced in weight. Since the hole portion 12 made of the through hole is closed by the lid member 21, pressure resistance or sealing performance is ensured. The metal ring 11 is made of a high-strength metal and has a large thickness, and the portion on the outer peripheral side of the hole 12 is a caulking portion. Therefore, even if the hole 12 is provided, the necessary strength is obtained. It is secured. Therefore, an oil seal for an absorber that can reduce the weight of the metal ring 11 without reducing the strength of the metal ring 11 and can meet the recent demand for weight reduction of parts has been realized.

Second and third embodiments ...
In the first embodiment, the annular cover member 21 is similarly laminated on the inner end surface of the annular metal ring 11 in a non-adhesive manner. However, these are set in a mold and the rubber-like elastic body 31 is attached. There is a concern that these may shift from each other when molding. Therefore, in order to suppress this, as shown in FIG. 2A as a second embodiment, a cylindrical engaging portion 22 is integrally formed on the inner periphery of the lid member 21, and the lid member 21 is L-shaped in cross section. The cylindrical engaging portion 22 is engaged with the inner peripheral surface of the metal ring 11. According to this, the lid member 21 is accurately positioned with respect to the metal ring 11, and mutual displacement can be suppressed. Further, as shown in FIG. 2B as a third embodiment, the distal end 23 of the cylindrical engagement portion 22 is extended and bent outward in the radial direction so that the outer end surface of the metal ring 11 is wrapped around. May be.

Fourth embodiment ...
FIG. 3 shows an oil seal for a shock absorber according to a fourth embodiment of the present invention, and the oil seal is configured as follows.

  That is, first, a metal ring 11 is provided between an end surface portion of a rod guide 41 which is a casing in a shock absorber and a crimping portion 42a at the tip of an outer cylinder 42, and a rubber-like elastic body 31 is attached to the metal ring 11. ing. On the end surface portion of the rod guide 41, an annular caulking projection 41a is provided for strongly pressing the oil seal during caulking.

  The metal ring 11 is formed in an annular shape with a high-strength metal (for example, SAPH, SPFH) and has a large thickness (for example, a thickness of about 3.2 mm), but the hole 12 is formed to reduce the weight. The hole 12 is formed by a bottomed counterbored hole that opens only on one surface (outer end surface) in the thickness direction of the metal ring. In addition, the hole portion 12 is disposed approximately at the center in the radial direction of the metal ring 11 and a plurality (six locations in the drawing) are provided on the circumference of the metal ring 11. Since the hole 12 is a bottomed counterbored hole, it is closed by the hole bottom 13.

  The rubber-like elastic body 31 also has an annular shape, and is vulcanized and bonded to the metal ring 11 at the same time as the molding. The rubber-like elastic body 31 is slidably in close contact with the peripheral surface of the rod 43 to mainly seal the pressure oil inside the absorber. A sealing lip 32 that is slidably in close contact with the peripheral surface of the rod 43 and mainly seals dust or the like outside the absorber, and an inner peripheral cover that is attached to the inner peripheral surface of the metal ring 11. The attaching portion 34, the outer attaching portion 35 attached to a part of the outer end surface of the metal ring 11, the inner attaching portion 36 attached to the inner end surface of the metal ring 11, and the outer peripheral surface of the metal ring 11 An outer peripheral adherence portion 37, an intermediate lip 38 in close contact with the end surface portion of the rod guide 41, and an outer peripheral lip 39 in close contact with the outer peripheral surface of the protrusion 41a of the rod guide 41 and the inner peripheral surface of the outer cylinder 42. It is molded integrally.

  In the oil seal having the above-described configuration, since the hole portion 12 made of a counterbore hole is provided in the metal ring 11, the metal ring 11 is reduced in weight, and the oil seal as a whole is also reduced in weight. Since the hole portion 12 made of a counterbore is bottomed and has a tip end, pressure resistance or sealing performance is ensured. The metal ring 11 is made of a high-strength metal and has a large thickness, and the portion on the outer peripheral side of the hole 12 is a caulking portion. Therefore, even if the hole 12 is provided, the necessary strength is obtained. It is secured. Therefore, an oil seal for an absorber that can reduce the weight of the metal ring 11 without reducing the strength of the metal ring 11 and can meet the recent demand for weight reduction of parts has been realized.

Fifth Example ...
FIG. 4 shows an oil seal for a shock absorber according to a fifth embodiment of the present invention, and the oil seal is configured as follows. For the convenience of drawing, FIG. 4 is opposite in direction to FIGS.

  That is, first, a metal ring 11 is provided between an end surface portion of a rod guide 41 which is a casing in a shock absorber and a crimping portion 42a at the tip of an outer cylinder 42, and a rubber-like elastic body 31 is attached to the metal ring 11. ing. On the end surface portion of the rod guide 41, an annular caulking projection 41a is provided for strongly pressing the oil seal during caulking.

  The metal ring 11 is not a high-strength metal (for example, SAPH, SPFH) but a relatively low-strength metal (for example, SPCC) and has a small thickness (for example, less than 3.2 mm) as in the above embodiments. It is formed in an annular shape by a metal plate, and further has a hole 12 for weight reduction. The hole 12 is formed by making the metal ring 11 into a three-dimensional structure, that is, the material of the metal ring 11 is formed into an annular plane. It is formed by pressing into a shape (cross-sectional U shape) in which the cylindrical portions 15 and 16 are integrally formed respectively on the outer peripheral end portion and the inner peripheral end portion of the portion 14. The cylindrical portions 15 and 16 are respectively provided from the flat portion 14 toward the outside (upward in the drawing) of the absorber, and the hole portion 12 is opened toward the outside of the absorber.

  The rubber-like elastic body 31 also has an annular shape, and is vulcanized and bonded to the metal ring 11 at the same time as the molding. The rubber-like elastic body 31 is slidably in close contact with the peripheral surface of the rod 43 to mainly seal the pressure oil inside the absorber. A sealing lip 32 that is slidably in close contact with the peripheral surface of the rod 43 and mainly seals dust or the like outside the absorber, and an inner peripheral cover that is attached to the inner peripheral surface of the metal ring 11. The attaching part 34, the outer attaching part 35 attached to the outer end surface and the inner peripheral face of the inner peripheral side tubular part 16 of the metal ring 11, and the inner attaching part attached to the inner end face of the metal ring 11. 36, an outer periphery attached portion 37 attached to the outer peripheral surface of the metal ring 11, an intermediate lip 38 in close contact with the end surface portion of the rod guide 41, an outer peripheral surface of the protrusion 41a of the rod guide 41, and an inner periphery of the outer cylinder 42 An outer peripheral lip 39 that is in close contact with the surface is integrally formed.

  Reference numeral 45 denotes an assembly seal pressing jig used when the oil seal is assembled (when the outer cylinder is crimped), and the flat portion 14 of the metal ring 11 is pressed by the jig 45. The caulking part 42a at the tip of the outer cylinder 42 is caulked to strongly press the outer peripheral side cylindrical part 15 of the metal ring 11. Since the cylindrical portion 15 has a three-dimensional shape over the entire circumference, sufficient strength is ensured even if it is somewhat thin.

  In the oil seal having the above configuration, the metal ring 11 is formed in an annular shape by a metal plate having a relatively low strength and a small thickness, and further has a hole 12, and the hole 12 is formed by pressing the metal ring 11 into a three-dimensional shape. Since it is formed by having a structure, the weight of the metal ring 11 is reduced and the weight of the oil seal as a whole is reduced. Since the hole portion 12 accompanying the three-dimensionalization has a bottomed shape and is a leading end, pressure resistance or sealing performance is ensured. Since the metal ring 11 has a three-dimensional shape in the crimped portion (outer peripheral side cylindrical portion 15), the necessary strength is ensured. Therefore, an oil seal for an absorber that can reduce the weight of the metal ring 11 without reducing the strength of the metal ring 11 and can meet the recent demand for weight reduction of parts has been realized.

DESCRIPTION OF SYMBOLS 11 Metal ring 12 Hole part 13 Hole bottom part 14 Plane part 15,16 Cylindrical part 21 Lid member 22 Engagement part 23 Engagement part tip 31 Rubber-like elastic body 32 Seal lip 33 Dustrip 34 Inner circumference covering part 35 Outer covering Attachment portion 36 Inner attachment portion 37 Outer periphery attachment portion 38 Intermediate lip 39 Outer periphery lip 41 Rod guide 41a Caulking protrusion 42 Outer tube 42a Caulking portion 43 Rod 45 Assembly seal pressing jig

Claims (3)

In an oil seal for a shock absorber having a metal ring that is caulked and fixed by a casing of the shock absorber, and a seal lip that is attached to the metal ring and that is slidably in close contact with the peripheral surface of the rod,
The metal ring has a hole for reducing its weight,
The hole comprises a through hole that opens on both sides in the thickness direction of the metal ring,
In order to ensure pressure resistance in the through hole, a lid member made of a hard material is overlaid on the metal ring to close the through hole,
The weight of the lid member is set to be smaller than the weight reduction due to the formation of the through hole in the metal ring. In an oil seal for a shock absorber having a metal ring that is caulked and fixed by a casing of the shock absorber, and a seal lip that is attached to the metal ring and that is slidably in close contact with the peripheral surface of the rod,
The metal ring has a hole for reducing its weight,
The oil seal according to claim 1, wherein the hole portion is a bottomed counterbore hole opened on one surface in the thickness direction of the metal ring. In an oil seal for a shock absorber having a metal ring that is caulked and fixed by a casing of the shock absorber, and a seal lip that is attached to the metal ring and that is slidably in close contact with the peripheral surface of the rod,
The metal ring has a hole for reducing its weight,
The hole portion is formed by pressing the material of the metal ring into a shape in which a cylindrical portion is formed integrally with an outer peripheral edge portion and an inner peripheral edge portion of an annular flat surface portion, respectively. .

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