Sealing device

Abstract

To make a turning-up phenomenon hard to occur in a lip part of a dust lip even if a flange is moved with eccentricity of a cylindrical body such as a plug tube or an injection pipe.SOLUTION: In a sealing device 11, a seal lip 33 and a dust lip 34 are provided in a substrate 32 mounted into an opening of an engine which communicates between an outer space O and an inner space I. A cylindrical body CY such as a plug tube 202 or an injection pipe 302 is disposed in a mounting hole 12 of the substrate 32. The seal lip 33 includes a lip part 33a which is bent from an end of the substrate 32 at the side of the inner space I to an inner peripheral side and in contact with the cylindrical body CY. The dust lip 34 includes a lip part 34a which extends from an end of the substrate 32 at the side of the outer space O so as to expand a diameter and is in contact with a flange FL provided in the cylindrical body CY. An outer peripheral surface 38 of the dust lip 34 is covered by a reinforcement member 51 having higher rigidity than that of the dust lip 34.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a sealing device. [Background technology]

[0002] In automobile engines, plug tube seals, injection pipe seals, and the like are used as sealing devices for auxiliary equipment.

[0003] A plug tube seal is shown in, for example, Patent Document 1 (see page 5, line 16 to page 7, line 1, and FIG. 1-2).

[0004] The plug tube seal (7) described in Patent Document 1 is attached to an opening (tube insertion hole 3a) provided in a head cover (rocker cover 3) of a cylinder head (2) with a plug tube (4) that positions an ignition plug (1) so as to guide its tip into the combustion chamber of the engine as a mating member, and seals the internal space of the cylinder head from the external space.

[0005] An injection pipe seal is shown in, for example, Patent Document 2 (see paragraphs 0016 to 0026 and figures 1 to 2).

[0006] The injection pipe seal described in Patent Document 2 is attached to an opening (mounting hole 21) provided in a cylinder head, with an injection pipe (injection pipe nut 5) that has an injector built in that injects an air-fuel mixture into an intake port or a combustion chamber as a mating member, and seals the internal space of the cylinder head from the external space. This injection pipe seal is composed of an oil seal (6) and a dust seal (7) that are provided separately (see Figures 2 and 3). The oil seal is disposed on the internal space side of the cylinder head to prevent oil leakage (see paragraph 0021). The dust seal is disposed on the external space side of the cylinder head to prevent the intrusion of foreign matter (see paragraph 0023).

[0007] Patent Document 3 discloses a sealing device (1) applicable to both plug tube seals and injection pipe seals (see paragraph 0012). Like Patent Document 2, this sealing device also includes a seal lip (seal lip portion 12) that seals oil and the like, and a dust lip (side lip portion 14) that prevents the intrusion of water, muddy water, and the like (see paragraphs 0010-0024 and Fig. 1).

[0008] The sealing device described in Patent Document 3 differs from the seal structure described in Patent Document 2 in two major points.

[0009] The first point is that in the sealing device described in Patent Document 3, the seal lip (oil seal 6 in Document 2, seal lip portion 12 in Document 3) and the dust lip (dust seal 7 in Document 2, side lip portion 14 in Document 3) are molded integrally (see paragraph 0014 of Patent Document 3).

[0010] Secondly, in the sealing device described in Patent Document 3, only the seal lip (seal lip portion 12) comes into contact with the plug tube that covers the spark plug, while the dust lip (side lip portion 14) comes into contact with a mating member (103), which is, for example, the upper portion of the coil body of the ignition device (see paragraph 0018 and figures 2-3 of Patent Document 3). In accordance with the mating member that is arranged in a direction perpendicular to the plug tube, Patent Document 3 states regarding the shape of the dust lip, ".... before assembly, the side lip portion 14 is inclined to have a shape that expands in diameter toward the side O opposite to the object to be sealed, as shown in Figure 1" (see paragraph 0018). [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Utility Model Application Publication No. 02-096456 [Patent Document 2] Japanese Patent Application Publication No. 07-259692 [Patent Document 3] Patent Publication No. 2021-092271 Summary of the Invention [Problem to be solved by the invention]

[0012] In the sealing device described in Patent Document 3, it is assumed that the mating member (103) that is the contact target of the dust lip (side lip portion 14) is integrally provided with a cylindrical body such as a plug tube or an injection pipe. For example, the mating member may be a flange of the cylindrical body.

[0013] In this type of structure, if the cylindrical body becomes eccentric when installed, the flange will be displaced in a direction perpendicular to the axial direction of the cylindrical body. If the lip of the dust lip is in contact with the flange at this time, the lip may deform to follow the flange. This is the phenomenon known as "turning up."

[0014] A particularly problematic phenomenon is the curling phenomenon, where the lip part of the dust lip is bent inward when the flange moves inward (in the direction of the white arrow) at the contact point with the lip part of the dust lip, as shown in Figure 6. If the tubular part is installed in the desired position in this state, the lip part of the dust lip will maintain the shape in which the curling phenomenon occurred. This may result in a decrease in the effectiveness of preventing the intrusion of foreign matter such as muddy water.

[0015] Improvement is needed.

[0016] An object of the present disclosure is to make it difficult for the lip portion of the dust lip to turn over even if the flange moves due to eccentricity of a cylindrical body such as a plug tube or an injection pipe. [Means for solving the problem]

[0017] One aspect of the sealing device comprises an elastic annular base that is attached to an opening connecting the external space and internal space of an equipment and surrounds a cylindrical body that penetrates the opening and has a flange on the external space side, a seal lip that bends inwardly from the end of the base on the internal space side and has a lip portion at its tip that contacts the cylindrical body, a dust lip that extends in diameter from the end of the base on the external space side and has a lip portion at its tip that contacts the flange, and a reinforcing member of higher rigidity than the dust lip that covers the outer surface of the dust lip. Effect of the Invention

[0018] Even if the flange moves due to eccentricity of a cylindrical body such as a plug tube or an injection pipe, the lip portion of the dust lip is less likely to turn over. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram showing a general structure of an engine. [Diagram 2] FIG. 2 is a vertical cross-sectional view showing the sealing device of the present embodiment. [Diagram 3] 5A to 5C are vertical cross-sectional views showing the process of mounting a cylindrical body (a plug tube, an injection pipe) to a sealing device, in half cross-section. [Figure 4] FIG. 4 is a vertical cross-sectional view showing a half cross-section of a cylindrical body (a plug tube, an injection pipe) mounted on a sealing device. [Diagram 5] FIG. 4 is a vertical cross-sectional view showing a half cross-section of a sealing device of a comparative example. [Figure 6] FIG. 11 is a vertical cross-sectional view showing a half cross-section of a cylindrical body (a plug tube, an injection pipe) mounted on a sealing device of a comparative example. [Figure 7] 4 is an enlarged vertical cross-sectional view showing the periphery of a dust lip in the sealing device of the embodiment. FIG. [Figure 8] FIG. 4 is a vertical cross-sectional view showing a sealing device according to another embodiment. [Figure 9]FIG. 4 is a vertical cross-sectional view showing a half cross-section of a cylindrical body (a plug tube, an injection pipe) mounted on a sealing device. [Figure 10] FIG. 4 is an enlarged vertical cross-sectional view showing the dust lip and its surroundings. [Figure 11] FIG. 11 is a vertical cross-sectional view showing a sealing device according to still another embodiment. [Figure 12] FIG. 4 is a vertical cross-sectional view showing a half cross-section of a cylindrical body (a plug tube, an injection pipe) mounted on a sealing device. [Figure 13] FIG. 4 is an enlarged vertical cross-sectional view showing the dust lip and its surroundings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] An embodiment will be described with reference to the drawings. As shown in Fig. 1, this embodiment is a sealing device 11 (11A) for a plug tube 202, which will be described later, and a sealing device 11 (11B) for an injection pipe 302. These sealing devices 11 (11A, 11B) are attached to an engine 101, which is an apparatus, for use.

[0021] The following items will be explained. 1. Configuration (1) Engine Overview (2) Sealing device (2-1) Common structure (2-2) Elastic body (a) Substrate (b) Seal lip (c) Dust Lip (2-3) Reinforcement members (2-4) Reinforcement ring (2-5) Garter spring 2. Effects (1) Basic effects (1-1) Plug tube seal (1-2) Injection pipe seal (2) Eccentricity of the cylindrical body (3)Other 3. Alternative embodiments 4. Further embodiment 5. Variations

[0022] 1. Configuration (1) Engine Overview 1 is a schematic diagram showing the general structure of an engine. This engine 101 is a DOHC type reciprocating engine, and has a cylinder head 131 fixed to the upper part of a cylinder block 111 that holds a piston 102 so that it can reciprocate freely.

[0023] The cylinder head 131 forms a combustion chamber 103 between itself and the piston 102, and is provided with an intake port 132 and an exhaust port 133 that communicate with the combustion chamber 103. A plurality of valves 134 are attached to the cylinder head 131 so as to be able to reciprocate freely, so as to open and close the openings of the intake port 132 and the exhaust port 133 that communicate with the combustion chamber 103. These valves 134 are driven by a valve mechanism 137, such as a valve spring 135 and a camshaft 136, to open and close the intake port 132 and the exhaust port 133.

[0024] An ignition plug 201 is detachably attached to the cylinder head 131. The ignition plug 201 is screwed into the cylinder head 131 so that a gap portion 201a is exposed inside the combustion chamber 103. The cylinder head 131 has a plug hole 138, which is screwed into the ignition plug 201, between an intake side valve 134 and an exhaust side valve 134. The ignition plug 201 screwed into the plug hole 138 is fixed so that a gap portion 201a is exposed to the combustion chamber 103.

[0025] The cylinder head 131 incorporates a plug tube 202 for accommodating an ignition plug 201. The plug tube 202 is a cylindrical body CY (see FIGS. 3 and 4) that houses the ignition plug 201, and is disposed so as to extend upward from the plug hole 138 and is fixed inside the cylinder head 131.

[0026] A head cover 151 that covers the valve train 137 is attached to the top of the cylinder head 131. The head cover 151 has two parallel bulges 152 for accommodating two camshafts 136, one on the intake side and one on the exhaust side, provided on the cylinder head 131, and an opening OP (OP1) with an opening AP (AP1) for inserting an ignition plug 201 is provided between these bulges 152. A plug tube 202 in which the ignition plug 201 is disposed penetrates the opening AP1 and is exposed to the external space O. This makes it possible to replace the ignition plug 201 from the external space O.

[0027] An opening OP (OP1) of the head cover 151 is provided with a sealing device 11 (11A) for the plug tube 202. The sealing device 11A contacts the plug tube 202 as a mating member with a lip portion 33a (see FIGS. 2 to 4) of a seal lip 33 having a sealing function against its outer peripheral surface, thereby sealing the internal space I of the cylinder head 131 from the external space O. Details of the sealing device 11A will be described later.

[0028] An injector 301 is provided in the intake port 132 of the cylinder head 131. The injector 301 is held in the cylinder head 131 with an injection port for the air-fuel mixture facing the intake port 132 so as to be able to inject the air-fuel mixture into the intake port 132.

[0029] An injection pipe 302 is connected to the injector 301. The injection pipe 302 is a pipe-like member that supplies fuel to the injector 301 and leads the electrical wiring of the injector 301 to the outside space O. Because of this role, the injection pipe 302 must be led out to the outside space O. Therefore, the engine 101 has an opening OP (OP2) having an opening AP (AP2) in the head cover 151, and the injection pipe 302 is led out to the outside space O from the opening AP (AP2).

[0030] A sealing device 11 (11B) for the injection pipe 302 is provided at an opening OP (OP2) of the cylinder head 131. The sealing device 11B contacts the outer peripheral surface of the injection pipe 302 with a lip portion 33a (see Figs. 2 to 4) of a seal lip 33, thereby sealing the internal space I of the cylinder head 131 from the external space O. Details of the sealing device 11B will be described later.

[0031] (2) Sealing device A sealing device 11 (11A, 11B) of this embodiment will be described with reference to the drawings.

[0032] Fig. 2 is a vertical cross-sectional view of the sealing device 11. Fig. 3 and Fig. 4 show the sealing device 11 in a half cross-section at a central axis A described later. The remaining half, which is not shown in Fig. 3 and Fig. 4, is symmetrical to the illustrated part. This also applies to Fig. 5 and Fig. 6 showing a sealing device 11C of a reference example, Fig. 8 and Fig. 9 showing another embodiment, and Fig. 11 and Fig. 12 showing yet another embodiment.

[0033] (2-1) Common structure The sealing device 11A for the plug tube 202 has an annular overall shape (see Figs. 2 to 4). The injection pipe 302 also has an annular overall shape (see Figs. 2 to 4), and the two have a common shape. The two types of sealing devices 11A and 11B also have a common sealing structure in which a seal lip 33 and a dust lip 34 are brought into contact with a cylindrical body CY inserted into an opening AP (AP1, AP2) of an opening OP (OP1, OP2) provided in the engine 101 to seal a gap G (see Fig. 1) between the opening AP (AP1, AP2) and the cylindrical body CY (see Figs. 2 to 4). These two types of sealing devices 11A and 11B basically have the same structure, except for the configuration corresponding to individual attributes such as the difference in diameter between the plug tube 202 and the injection pipe 302. Therefore, in this embodiment, a common basic structure is extracted from the two types of sealing devices 11A and 11B and introduced as a single sealing device 11.

[0034] As shown in FIGS. 2 to 4, many areas of the sealing device 11 are formed by the elastic body 31, and the reinforcing ring 61 and the garter spring 71 are embedded inside the elastic body 31.

[0035] (2-2) Elastic body Before describing the elastic body 31 which constitutes the main part of the sealing device 11, the following definitions will be given.

[0036] 2 to 4, an arrow D indicates the insertion direction of the cylindrical body CY into the opening AP of the opening OP. The sealing device 11 (11A, 11B) is attached to the opening OP (OP1, OP2), and the cylindrical body CY is inserted and attached into an attachment hole 12 provided in the sealing device 11. The insertion direction of the cylindrical body CY at this time is the insertion direction D.

[0037] Reference symbol A denotes a central axis of the sealing device 11. The central axis A of the sealing device 11 passes through the center of the mounting hole 12. The sealing device 11 is mounted to the openings OP (OP1, OP2) with their axes aligned, and therefore the central axis A is also the central axis of the openings OP and the opening AP.

[0038] The insertion direction D of the cylindrical body CY is theoretically aligned with the direction of the opening AP and the central axis A of the sealing device 11. However, when inserting the cylindrical body CY into the opening AP, the cylindrical body CY may become eccentric in a direction perpendicular to the central axis A. Arrow E shown in Figures 2 to 4 indicates the eccentricity direction of the cylindrical body CY.

[0039] The elastic body 31 is an annular member formed integrally with a base body 32, a seal lip 33, and a dust lip 34 using an elastic material such as synthetic rubber, and has a perfect circular annular shape. The central axes of the base body 32, the seal lip 33, and the dust lip 34 coincide with the central axis A of the sealing device 11. In this specification, the term central axis A means the central axes of the sealing device 11, the base body 32, the seal lip 33, the dust lip 34, the opening OP, and the opening AP.

[0040] (a) Substrate The base 32 has a cylindrical shape that fits into the openings AP (AP1, AP2) of the openings OP (OP1, OP2). The outer diameter of the base 32 is slightly larger than the inner diameter of the openings AP, and by being inserted into the openings AP, the base 32 is attached to the openings OP while undergoing elastic deformation.

[0041] More specifically, when used as the sealing device 11A for the plug tube 202, the outer diameter of the base 32 is determined so as to fit an opening OP1 having an opening AP1 for inserting the plug tube 202 in which the ignition plug 201 is disposed. When used as the sealing device 11B for the injection pipe 302, the outer diameter of the base 32 is determined so as to fit an opening OP2 having an opening AP2 for inserting the injection pipe 302 connected to the injector 301.

[0042] A large diameter portion 35 is provided on the outer circumferential surface of the base 32. When the base 32 is inserted into the opening AP, the large diameter portion 35 is crushed to increase the reaction force, thereby making the attachment state of the base 32 to the opening OP stronger.

[0043] A flange-shaped stopper 36 is provided on the end of the base 32 located on the external space O side. The stopper 36 extends perpendicularly in a direction in which the diameter increases from the outer periphery of the base 32. When the sealing device 11 is inserted into the opening AP, the stopper 36 abuts against the periphery of the opening AP to position the sealing device 11.

[0044] (b) Seal lip The seal lip 33 is provided at the end of the base 32 on the internal space I side. The seal lip 33 is bent inwardly from the end of the base 32 on the internal space I side toward the external space O side, and has a lip portion 33a at the bent tip. The lip portion 33a has an inner diameter that contacts the outer peripheral surface of the cylindrical body CY inserted into the mounting hole 12 of the sealing device 11.

[0045] More specifically, when used as the sealing device 11A for the plug tube 202, the inner diameter of the lip portion 33a of the seal lip 33 is set to be smaller than the outer diameter of the plug tube 202 in which the ignition plug 201 is disposed. When used as the sealing device 11B for the injection pipe 302, the inner diameter of the lip portion 33a of the seal lip 33 is set to be smaller than the outer diameter of the injection pipe 302 connected to the injector 301.

[0046] As described above, the seal lip 33 seals the inside of the cylinder head 131 from the external space O by bringing the lip portion 33a into contact with the outer circumferential surface of the cylindrical body CY with a predetermined contact pressure.

[0047] (c) Dust Lip The dust lip 34 is provided at the end of the base 32 on the external space O side. The dust lip 34 extends from the end of the base 32 on the external space O side so as to expand in diameter, and has a lip portion 34a at its tip. The lip portion 34a has an annular shape that contacts a flange FL, described later, provided on the cylindrical body CY.

[0048] With regard to the dust lip 34, the root portion that connects to the end portion of the base 32 on the external space O side is called the root 37, the surface on the outer periphery side is called the outer periphery surface 38, the surface on the inner periphery side is called the inner periphery surface 39, and the surface at the tip portion is called the tip surface 40. The lip portion 34a of the dust lip 34 is provided on an edge 41a at the boundary portion between the inner periphery surface 39 and the tip surface 40. The edge 41a of this boundary portion is located the furthest in the dust lip 34 towards the external space O.

[0049] As shown in FIG. 4, the dust lip 34 has a lip portion 34a that contacts a flange FL provided on the cylindrical body CY with a predetermined contact pressure, thereby sealing the inside of the cylinder head 131 from the outside space O.

[0050] (2-3) Reinforcement members In the sealing device 11 (11A, 11B) of the present embodiment, a reinforcing member 51 is fixed to the dust lip . The reinforcing member 51 is a member that covers the outer circumferential surface of the dust lip and has higher rigidity than the dust lip .

[0051] The reinforcing member 51 is provided over the entire outer peripheral surface 38 of the dust lip 34, that is, the entire circumferential region of the outer peripheral surface 38 from the base 37 to the tip portion. The tip portion of the outer peripheral surface 38 is defined by an edge 41b (see FIG. 7) that forms the boundary between the outer peripheral surface 38 and the tip surface 40. No reinforcing member 51 is provided on the tip surface 40. Therefore, the entire region of the outer peripheral surface 38 of the dust lip 34 from the base 37 to the edge 41b is covered with the reinforcing member 51 all around.

[0052] 2 to 4. At the base 37 of the dust lip 34, the reinforcing member 51 is bent at an acute angle, and the bent end portion wraps around the stopper 36 of the base body 32. The lower end portion of the reinforcing member 51 bent at such an acute angle is called a bent portion 52.

[0053] The dust lip 34 is originally a part of the elastic body 31, and is made of an elastic material such as synthetic rubber. As the synthetic rubber, for example, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM), fluororubber (FKM), etc. can be used.

[0054] The reinforcing member 51 is a member having higher rigidity than the dust lip 34. For example, a PTFE (polytetrafluoroethylene) film is used as the material of the reinforcing member 51. In addition, various materials can be used as the material of the reinforcing member 51 as long as the material has higher rigidity than the dust lip 34.

[0055] The reinforcing member 51 can be provided on the dust lip 34 by, for example, adhering and fixing it to the dust lip 34 or by integrating it with the elastic body 31 when molding it.

[0056] (2-4) Reinforcement ring The reinforcing ring 61 is intended to reinforce the strength of the base body 32 of the elastic body 31, and has an L-shaped cross section with a flange portion 63 provided on a tubular portion 62. The tubular portion 62 is embedded in the cylindrical portion of the base body 32, and the flange portion 63 is embedded in the stopper 36.

[0057] As shown in FIGS. 2 to 4, a bent portion of the reinforcing ring 61 having an L-shaped cross section faces a bent portion 52 of a reinforcing member 51 provided on the outer circumferential surface of the dust lip .

[0058] The material of the reinforcing ring 61 may be, for example, a metal material such as stainless steel, steel, aluminum, etc. Alternatively, the reinforcing ring 61 may be made of various resin materials, etc., as long as they have high rigidity.

[0059] (2-5) Garter spring The garter spring 71 is an annular coil spring with a diameter larger than that of the lip portion 33a of the seal lip 33. In the seal lip 33, the garter spring 71 is embedded on the outer diameter side of the lip portion 33a, and increases the contact pressure of the lip portion 33a against the outer circumferential surface of the cylindrical body CY.

[0060] 2. Effects (1) Basic effects (1-1) Plug tube seal In the cylinder head 131, a sealing device 11A for the plug tube 202 is attached to an opening OP1 for inserting the plug tube 202 in which the ignition plug 201 is disposed. The plug tube 202 is inserted and attached into the mounting hole 12 of the sealing device 11A according to the insertion direction D. Although not shown in FIG. 1, the plug tube 202 is provided with a flange FL (see FIGS. 3 to 4 and 7). The plug tube 202 is inserted until the flange FL hits a seat (not shown) provided in the cylinder head 131, and is fixed in that position.

[0061] When the plug tube 202 is attached to the opening OP1 in this manner, the axis of the plug tube 202 coincides with the central axis A of the opening OP1 and the sealing device 11A.

[0062] At this time, the lip portion 33a of the seal lip 33 comes into contact with the outer peripheral surface of the plug tube 202 with a predetermined contact pressure, sealing the inside of the cylinder head 131 from the external space O. This makes it possible to suppress oil leakage from the inside of the cylinder head 131 to the external space O.

[0063] As shown in FIG. 3, in the process of inserting the plug tube 202 into the opening OP1, that is, the mounting hole 12 of the sealing device 11A, the flange FL provided on the plug tube 202 approaches the dust lip .

[0064] 4, when the flange FL abuts against a seat (not shown) provided on the cylinder head 131 and the plug tube 202 is attached, the lip portion 34a of the dust lip 34 contacts the flange FL with a predetermined contact pressure, sealing the inside of the cylinder head 131 from the external space O. This makes it possible to prevent foreign matter such as sludge from entering the inside of the cylinder head 131 from the external space O.

[0065] (1-2) Injection pipe seal In the cylinder head 131, a sealing device 11B for the injection pipe 302 is attached to an opening OP2 for inserting an injection pipe 302 connected to an injector 301. The injection pipe 302 is inserted into an attachment hole 12 of the sealing device 11B in accordance with an insertion direction D and attached. Although not shown in FIG. 1, a flange FL is provided on the injection pipe 302 (see FIGS. 3 to 4 and 7). The injection pipe 302 is inserted until the flange FL hits a seat (not shown) provided on the cylinder head 131, and is fixed in that position.

[0066] When the injection pipe 302 is attached to the opening OP2 in this manner, the axis of the injection pipe 302 coincides with the central axis A of the opening OP2 and the sealing device 11B.

[0067] At this time, the lip portion 33a of the seal lip 33 comes into contact with the outer circumferential surface of the injection pipe 302 with a predetermined contact pressure, sealing the inside of the cylinder head 131 from the external space O. This makes it possible to suppress oil leakage from the inside of the cylinder head 131 to the external space O.

[0068] As shown in FIG. 3, in the process of inserting the injection pipe 302 into the opening OP2, that is, the mounting hole 12 of the sealing device 11B, the flange FL provided on the injection pipe 302 approaches the dust lip .

[0069] 4, when the flange FL abuts against a seat (not shown) provided on the cylinder head 131 and the injection pipe 302 is attached, the lip portion 34a of the dust lip 34 contacts the flange FL with a predetermined contact pressure, sealing the inside of the cylinder head 131 from the external space O. This makes it possible to prevent foreign matter such as sludge from entering the inside of the cylinder head 131 from the external space O.

[0070] (2) Eccentricity of the cylindrical body When inserting the cylindrical body CY (plug tube 202, injection pipe 302) into the opening OP (OP1, OP2) of the cylinder head 131, it is difficult to imagine that the axis of the cylindrical body CY will remain aligned with the central axis A of the opening OP (OP1, OP2) and the sealing device 11 (11A, 11B) throughout the entire process. The cylindrical body CY inevitably tends to become eccentric in the eccentric direction E. The phenomenon that occurs when the cylindrical body CY becomes eccentric in this way will be explained using the sealing device 11C of the reference example as an example.

[0071] Fig. 5 is a vertical cross-sectional view showing a half cross-section of a sealing device 11C of a comparative example. This sealing device 11C has a common configuration with the sealing device 11 (11A, 11B) of the present embodiment, except that the dust lip 34 is not provided with a reinforcing member 51. The reference numerals shown in Figs. 5 and 6 have the letter "C" added to their ends, such as the seal lip 33C and the dust lip 34C. However, the letter "C" is not added to the external space O, the internal space I, the cylindrical body CY, the flange FL, the insertion direction D, the eccentric direction E, and the central axis A.

[0072] When the cylindrical body CY is inserted into the opening OP, the flange FL of the cylindrical body CY hits a seat (not shown) provided on the cylinder head 131 (see FIG. 1) and is positioned, and the lip portion 34aC of the dust lip 34C comes into contact with the flange FL. At this time, eccentricity may occur in the cylindrical body CY during the period from when the flange FL comes into contact with the lip portion 34aC to when the position is restricted.

[0073] As shown in Fig. 6, when the eccentric direction E is the direction indicated by the white arrow in Fig. 6, that is, the eccentricity is in the direction toward the inner diameter of the lip portion 34aC of the dust lip 34C, the lip portion 34aC may deform following the flange FL. This is a phenomenon called "turning up." Fig. 6 shows the state where the turning up phenomenon occurs in the lip portion 34aC.

[0074] If the cylindrical body CY is placed in the desired position in this state, the lip portion 34aC of the dust lip 34C will maintain the shape in which the curling phenomenon occurred, which may result in a decrease in the effectiveness of preventing the intrusion of foreign matter such as muddy water.

[0075] 7, the dust lip 34 of this embodiment is provided with a reinforcing member 51. Therefore, even if a force F1 that tries to make the lip portion 34a follow the inner diameter direction is generated due to the eccentricity of the cylindrical portion 62 during the period from when the flange FL of the cylindrical body CY comes into contact with the lip portion 34a of the dust lip 34 to when the position is restricted, the dust lip 34 is less likely to turn over. This is because the reaction force F2 that the reinforcing member 51 exerts on the dust lip 34 is greater than the force F1 that tries to make the lip portion 34a of the dust lip 34 turn over.

[0076] In other words, the reinforcing member 51 has a rigidity that is capable of generating a reaction force F2 on the dust lip 34 that is greater than the force F1 that tends to cause the lip portion 34a of the dust lip 34 to turn over.

[0077] Therefore, according to the sealing device 11 (11A, 11B) of this embodiment, even if the flange FL moves due to eccentricity of the cylindrical body CY such as the plug tube 202 or the injection pipe 302, the curling phenomenon is less likely to occur in the lip portion 34a of the dust lip 34.

[0078] (3)Other According to this embodiment, the reinforcing member 51 covers the outer peripheral surface 38 of the dust lip 34 from the tip side to the base 37 of the dust lip 34. Therefore, a large reaction force F2 can be generated over the entire outer peripheral surface 38 of the dust lip 34 against a force F1 that tends to cause the lip portion 34a of the dust lip 34 to turn over.

[0079] The reinforcing member 51 has a bent portion 52 that is bent at an acute angle to wrap around the stopper 36 of the base body 32 at a position that covers the base 37 of the dust lip 34. Therefore, a larger reaction force F2 can be generated against the force F1 that tends to cause the lip portion 34a of the dust lip 34 to turn over. The fact that the bent portion 52 of the reinforcing ring 61 embedded in the elastic body 31 faces the reinforcing member 51 also contributes to the increase in the reaction force F2 against the force F1.

[0080] The lip portion 34a of the dust lip 34 is provided on an edge 41a of the boundary between the inner circumferential surface 39 and the tip surface 40 of the dust lip 34. Due to such an arrangement of the lip portion 34a, it is possible to prevent the reinforcing member 51 from interfering with the sealing action of the lip portion 34a with respect to the flange FL of the cylindrical body CY.

[0081] By providing the reinforcing member 51 with a PTFE film, a reaction force F2 greater than the force F1 can be generated in the dust lip 34 without losing the elasticity required for the sealing action.

[0082] 3. Alternative Embodiments Another embodiment of the sealing device 11 will be described with reference to Figures 8 to 10. The same parts as those in the sealing device 11 described with reference to Figures 1 to 7 are designated by the same reference numerals, and description thereof will be omitted.

[0083] As shown in FIG. 8, the sealing device 11 of this embodiment is different from the sealing device 11 described based on FIGS. 1 to 7 in terms of a reinforcing member 51, but is the same in other respects.

[0084] The reinforcing member 51 of the present embodiment does not include a bent portion 52 .

[0085] On the other hand, the reinforcing member 51 has a rigidity sufficient to generate a reaction force F2 in the dust lip 34 that is greater than the force F1 when a force F1 occurs that attempts to cause a curling phenomenon in the lip portion 34a of the dust lip 34 (see Figure 10).

[0086] 9 shows a state in which the cylindrical body CY is eccentric in the eccentric direction E shown by the outline arrow from when the flange FL provided on the cylindrical body CY comes into contact with the lip portion 34a of the dust lip 34 until the position is regulated during the insertion operation of the cylindrical body CY into the mounting hole 12 of the sealing device 11. At this time, the flange FL moves to the right in FIG. 9 due to the eccentricity of the cylindrical body CY, and moves with the lip portion 34a in contact, causing the dust lip 34 to turn over.

[0087] In contrast, in the present embodiment, as shown in FIG. 10, the reaction force F2 that the reinforcing member 51 exerts on the dust lip 34 is greater than the force F1 that tends to cause the lip portion 34a of the dust lip 34 to turn over, making it less likely that the dust lip 34 will turn over.

[0088] 4. Further embodiment Still another embodiment of the sealing device 11 (11A, 11B) will be described with reference to Figures 11 to 13. The same parts as those of the sealing device 11 (11A, 11B) described with reference to Figures 1 to 7 are indicated by the same reference numerals, and description thereof will be omitted.

[0089] As shown in FIG. 11, the sealing device 11 of this embodiment is different from the sealing device 11 described based on FIGS. 1 to 7 in terms of a reinforcing member 51, but is the same in other respects.

[0090] The reinforcing member 51 of the present embodiment is not provided on the entire outer peripheral surface 38 of the dust lip 34, and does not include a bent portion 52. The reinforcing member 51 is provided only in about a half area on the tip side of the entire circumference of the outer peripheral surface 38 of the dust lip 34.

[0091] On the other hand, the reinforcing member 51 has a rigidity sufficient to generate a reaction force F2 in the dust lip 34 that is greater than the force F1 when a force F1 occurs that attempts to cause a curling phenomenon in the lip portion 34a of the dust lip 34 (see Figure 13).

[0092] 12 shows a state in which the cylindrical body CY is eccentric in the eccentric direction E shown by the white arrow from when the flange FL provided on the cylindrical body CY comes into contact with the lip portion 34a of the dust lip 34 until the position is regulated during the insertion operation of the cylindrical body CY into the mounting hole 12 of the sealing device 11. At this time, the flange FL moves to the right in FIG. 12 due to the eccentricity of the cylindrical body CY, and moves with the lip portion 34a in contact, causing the dust lip 34 to turn over.

[0093] In contrast, in the present embodiment, as shown in FIG. 13, the reaction force F2 that the reinforcing member 51 exerts on the dust lip 34 is greater than the force F1 that tends to cause the lip portion 34a of the dust lip 34 to turn over, making it less likely that the dust lip 34 will turn over.

[0094] 5. Variations Various modifications and variations are possible when implementing the present invention.

[0095] For example, in the present embodiment, the seal lip 33 is shaped to bend inward from the end of the base 32 on the internal space I side toward the external space O side, but the seal lip 33 does not necessarily have to have such a shape. As an example, the seal lip 33 may be shaped to bend inward from the end of the base 32 on the internal space I side without going toward the external space O side.

[0096] The stopper 36 provided on the elastic body 31 and the flange portion 63 of the reinforcing ring 61 that reinforces the stopper 36 are not necessarily essential, and the configuration may be such that these are not provided.

[0097] Any other variations or modifications are permitted. [Explanation of symbols]

[0098] 11 Sealing device 11A Sealing device (for plug tube) 11B Sealing device (for injection pipe) 11C Sealing device (comparative example) 12 Mounting hole 31 Elastic body 32 Base 33 Seal lip 33C Seal lip 33a Lip 33aC Lip 34 Dust Trip 34C Dust Lip 34a Lip 34aC Lip 35 Large diameter section 36 Stopper 37 Base 38 Outer surface 39 Inner surface 40 Tip surface 41a Edge 41b Edge 51 Reinforcement member 52 Bend 61 Reinforcement ring 62 Cylindrical part 63 Flange 71 Garter Spring 101 Engine (equipment) 102 Piston 103 Combustion chamber 111 Cylinder block 131 Cylinder head 132 Intake port 133 Exhaust port 134 Valve 135 Valve spring 136 Camshaft 137 Valve train 138 Plug hole 151 Head Cover 152 Bulge 201 Spark plug 201a Gap section 202 Plug tube 301 Injector 302 Injection pipe A center axis AP, AP1, AP2 aperture CY Cylindrical body D Insertion direction E eccentric direction FL Flange G gap I Interior space O External space OP, OP1, OP2 opening

Claims

1. an elastic annular base body that is attached to an opening that connects an external space and an internal space of the device and that surrounds a cylindrical body that passes through the opening and has a flange on the external space side; a seal lip that is bent from an end of the base body on the internal space side toward an inner periphery and has a lip portion at a tip end thereof that contacts the cylindrical body; a dust lip extending from an end of the base body on the external space side so as to expand in diameter and having a lip portion at a tip end thereof in contact with the flange; A reinforcing member covering an outer peripheral surface of the dust lip and having higher rigidity than the dust lip; A sealing device comprising:

2. The reinforcing member covers the outer peripheral surface of the dust lip from the tip side to the base side of the dust lip. The sealing device of claim 1 .

3. The lip portion of the dust lip is provided on the edge of the boundary portion between the inner peripheral surface and the tip surface of the dust lip. The sealing device according to claim 2 .

4. The reinforcing member has a bent portion that is bent at an acute angle and wraps around the base body at a position that covers the base of the dust lip. The sealing device according to claim 2 .

5. a reinforcing ring made of metal and having an annular shape is embedded in the base; The reinforcing ring faces the bent portion of the reinforcing member. The sealing device according to claim 4.

6. The reinforcing member covers an outer circumferential surface of the dust lip at least on the tip side of the dust lip. The sealing device of claim 1 .

7. The lip portion of the dust lip is provided on the edge of the boundary portion between the inner peripheral surface and the tip surface of the dust lip. The sealing device according to claim 6.

8. The reinforcing member is a PTFE film. The sealing device of claim 1 .

9. the device is an engine head cover, The cylindrical body is an injection pipe in which an injector is disposed. A sealing device according to any one of claims 1 to 8.

10. the device is an engine head cover, The cylindrical body is a plug tube in which an ignition plug is disposed. A sealing device according to any one of claims 1 to 8.

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