Sealing device

Abstract

To provide a sealing device configured to reduce an insertion load that facilitates insertion while maintaining sealing performance corresponding to resistance to loosening.SOLUTION: A sealing device is configured to seal a hole part 2 by pressing a lip against an inner wall 2c of the hole part 2 by elastic force. A plurality of sealing parts 1 having an inverted truncated cone shape, each of which has a first tapered surface 15 in a direction from a minimum circle diameter surface to a maximum circle diameter surface, are integrally molded in a multistage shape. At least one of the sealing parts 1 includes a second tapered surface 16 which is formed continuously from the first tapered surface 15 and has an inclination angle that is different from that of the first tapered surface 15, and has a relationship of θ1>θ2 where θ1 is the inclination angle of the first tapered surface 15, and θ2 is the inclination angle of the second tapered surface 16.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sealing device for sealing a hole portion.

Background Art

[0002] Conventionally, a sealing device having a serrated sealing portion has been known. For example, in Patent Document 1, the outer rib of a plug (sealing device) inserted into an annular space has a serrated shape in cross section, and the serrated shape has an ascending surface that rises radially outward toward the large-diameter end portion of the plug and a descending surface having an inclined inward bend. It is disclosed that it has.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, generally, in such a sealing device, if the insertion load is large, a large force is required for insertion, making it difficult to insert, so it is desirable to reduce the insertion load as much as possible. In this case, to reduce the insertion load, the press-fit allowance may be reduced, but then there is a risk that the extraction load will decrease and it will be easy to come out.

[0005] Therefore, an object of the present invention is to provide a sealing device that reduces the insertion load for easy insertion while maintaining the sealing property against coming off.

Means for Solving the Problems

[0006] In order to achieve the above object, a first invention is a sealing device that presses a lip against the inner wall of a hole by an elastic force to seal the hole, and a sealing portion having an inverted frustum shape with a first tapered surface extending from a minimum diameter surface portion to a maximum diameter surface portion is integrally formed in a plurality of stages, and at least one sealing portion includes a second tapered surface that is continuously formed from the first tapered surface and has an inclination angle different from that of the first tapered surface, and when the inclination angle of the first tapered surface is θ1 and the inclination angle of the second tapered surface is θ2, it is characterized in that the relationship θ1>θ2 is satisfied. A second invention is characterized in that, in the first invention, the ratio θ1 / θ2 of the inclination angles of θ1 and θ2 is 2 to 14. A third invention is characterized in that, in the first invention or the second invention, when the press-fitting direction width of the second tapered surface is d and the press-fitting margin of the lip of the maximum diameter surface portion of the sealing portion not provided with the second tapered surface is c, the relationship c>d is satisfied.

Effects of the Invention

[0007] According to the present invention, it is possible to provide a sealing device that reduces the insertion load for easy insertion while maintaining the sealing performance against disengagement.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] [Sealing Device] Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the sealing device 1 of the present invention presses the lips (the first lip 11a, the second lip 11b, and the third lip 11c) against the inner wall 2c of the hole 2 by elastic force to seal the hole 2. A sealing portion 11 having an inverted frustum shape with a funnel-shaped first tapered surface 15 extending from the minimum diameter surface portion to the maximum diameter surface portion is integrally formed in a plurality of stages. At least one sealing portion 11 includes a funnel-shaped second tapered surface 16 that is continuously formed from the first tapered surface 15 and has an inclination angle different from that of the first tapered surface 15. When the inclination angle of the first tapered surface 15 is θ1 and the inclination angle of the second tapered surface 16 is θ2, they have a relationship of θ1>θ2.

[0010] The sealing device 1 shows a state in which the sealing portion 11 is press-fitted toward the opening 2a of the hole 2 (see the arrow in FIG. 1 and reference numeral T1), and is about to seal the hole 2. That is, the lips (the first lip 11a, the second lip 11b, and the third lip 11c) are pressed against the inner wall 2c of the hole 2 by elastic force to seal the hole 2.

[0011] Further, the sealing device 1 has a sealing portion 11 of the first lip 11a, the second lip 11b, and the third lip 11c that protrudes in the radial direction orthogonal to the axis T in the length direction and is press-fitted into the hole 2 to seal the hole 2. An inverted frustum-shaped sealing portion 11 having a first tapered surface 15 extending from the small diameter surface portion to the maximum diameter surface portion is integrally formed in a plurality of stages. And the lip of at least one sealing portion 11 includes a funnel-shaped second tapered surface 16 that is continuously formed from the funnel-shaped first tapered surface 15 and has an inclination angle different from that of the first tapered surface 15.

[0012] When the sealing portion 11 is pressed inwardly of the hole 2 in this way, during the pressing process, the top portion (the maximum diameter circumference of each lip) of the sealing portion 11 contacts the inner wall 2c of the hole 2 in the width direction of the hole 2, while the press-fitting allowance c of the sealing portion 11 bends so as to narrow. As a result, the press-fitting stop portion 12 contacts the edge end surface 2b of the opening of the hole 2, and the entire sealing portion 11 can be smoothly inserted until the hole 2 is sealed. And the sealing portion 11 is mounted in a press-fitted state in the hole 2. Note that the present invention is not limited to this embodiment, and the invention that can be changed and improved without departing from the gist of the present invention is also included.

[0013] As shown in FIG. 1, three first lip 11a, second lip 11b, and third lip 11c are arranged on the coaxial T in the length direction in the sealing portion 11 of the present embodiment. The frustum of a cone shapes of these first lip 11a, second lip 11b, and third lip 11c have a predetermined thickness (height) smaller than the width (outer diameter), and the corresponding outer diameter of the upper side is smaller than the outer diameter corresponding to the lower side. Further, they protrude in the radial direction orthogonal to the length direction, and have a serrated cross-sectional shape by stacking these lips coaxially with the axis T in a plurality of stages (three stages).

[0014] The reason why the first lip 11a, second lip 11b, and third lip 11c are stacked in a plurality of stages with the frustum of a cone shape centered on the axis T in the length direction is that it makes it easier to press-fit the sealing portion 11 when sealing the hole portion 2. Further, the outer dimensions of the sealing portion 11 having such a shape are set so that it can be press-fitted into the hole portion 2.

[0015] Further, the first lip 11a, second lip 11b, and third lip 11c have a first tapered surface 15 on the outer peripheral inclined side of the frustum of a cone shape. That is, it has a tapered surface that becomes smaller in diameter in the direction of insertion into the hole portion 2 (arrow in FIG. 1). This tapered surface is inclined so as to rise outward in the radial direction toward the base portion 13. Here, the inclination angle θ0 is set to approximately 30°, but is not limited to this angle.

[0016] Regarding the dimensions of the present embodiment, when the inner diameter b of the hole portion 2 is 19.75 mm so that the sealing portion 11 can be inserted into the hole portion 2, the outer diameter a of the maximum outer periphery of the sealing portion 11 is 21.25 mm. Note that the number of lips in this embodiment is not limited to three, and may be a plurality such as four or five, and the outer diameter a of the sealing portion 11 can be arbitrarily changed according to the inner diameter b of the hole portion 2.

[0017] In addition, the sealing device 1 according to the present embodiment integrally forms a frustum-shaped base portion 13 above the sealing portion 11 and a columnar knob portion 14 above the base portion 13. This knob portion 14 has a disk shape with a horizontally U-shaped concave center and is arranged on the axis T in the length direction. The reason for the concave disk shape is to allow an operator to hook a finger on the knob portion 14 when press-fitting the sealing portion 11 into the hole portion 2. In addition, when pulling out the sealing portion 11 from the state where the sealing portion 11 is attached to the hole portion 2 (see reference sign T2), this knob portion 14 can be gripped and easily pulled out.

[0018] In addition, in the sealing device 1 according to the present embodiment, a columnar press-fitting prevention portion 12 having an outer diameter larger than the inner diameter b of the hole portion 2 is formed below the knob portion 14 (which is also above the base portion 13). Further, this press-fitting prevention portion 12 has a disk shape that protrudes in the radial direction orthogonal to the length direction above the first lip 11a (the upper side of the frustum shape in FIG. 1). Thereby, the surface of the press-fitting prevention portion 12 on the side facing the hole portion 2 abuts against the edge end surface 2b around the opening 2a of the hole portion 2, and it can be prevented from being unnecessarily pushed into the depth of the hole portion 2. Note that the outer diameter size, height, etc. of the disk shape of the press-fitting prevention portion 12 can be appropriately set as long as the press-fitting prevention portion 12 abuts against the edge end surface 2b of the opening of the hole portion 2 by the sealing device 1 and the hole portion 2 is sealed.

[0019] In addition, the sealing device 1 according to the embodiment has a substantially identical frustum-shaped base portion 13 below the press-fitting prevention portion 12. This base portion 13 positions the sealing portion 11 between the knob portion 14 and connects both. The diameter f of the upper part 13a of the base portion 13 is smaller than the inner diameter b of the hole portion 2, and the diameter g of the lower part of the base portion 13 has a frustum shape with a dimension smaller than the diameter f. This is to prevent the press-fitting of the first lip 11a.

[0020] In addition, the material of the sealing device 1 of the present embodiment uses acrylic rubber, but the material may be an elastic body of a rubber material, for example, other thermosetting resin-based elastomers such as urethane rubber and fluorine rubber, or vulcanized rubber, etc. Note that the sealing device 1 does not have to be entirely made of the same elastic body. For example, the sealing portion 11 and the base portion 13 may be made of acrylic rubber, and the knob portion 14 may be made of another rubber material. In this case, the sealing portion 11, the base portion 13, and the knob portion 14 are connected in series, and the outer periphery is continuously connected and integrated without a joint.

[0021] [Second tapered surface] In this embodiment, at least one of the plurality of sealing portions 11 is continuously formed from the first tapered surface 15 and includes a funnel-shaped second tapered surface 16 having an inclination angle different from that of the first tapered surface 15. When the inclination angle of the first tapered surface 15 is θ1 and the funnel-shaped inclination angle of the second tapered surface 16 is θ2, the relationship θ1>θ2 will be described in detail.

[0022] The first lip 11a of the sealing portion 11 of this embodiment has a funnel-shaped second tapered surface 16 formed at the upper end 11a1 of the funnel-shaped first tapered surface 15 as shown in FIG. 2(A). That is, the first lip 11a has two different inclined surfaces (different inclination angles θ1 and inclination angle θ2) of the first tapered surface 15 and the second tapered surface 16 formed at the rising end portion of the first tapered surface 15. In this way, it is most effective as the sealing portion 11 to provide the second tapered surface 16 to the first lip 11a which is the lip at the rearmost end in the insertion direction. However, the second tapered surface may be provided on another lip, the second lip 11b or the third lip 11c, or may be formed on the lips of all stages. That is, at least one of the plurality of sealing portions 11 (lips), the sealing portion (lip) 11, may have the second tapered surface 16 in at least one or more.

[0023] In this way, by having the funnel-shaped second tapered surface 16 whose tapered shape is the outermost periphery, when the insertion load is large, it is difficult to insert (a large force is required for insertion). Therefore, it is desirable to reduce the insertion load as much as possible. On the other hand, to reduce the insertion load, the press-fit allowance c may be reduced, but then the extraction load will decrease and it will be easy to come off. The problem of the sealing device can be solved.

[0024] Regarding the inclination angle θ0 of the first tapered surface 15 of the second lip 11b and the third lip 11c that do not have the second tapered surface 16, although the same numerical value of 30° as the inclination angle θ1 of the first lip 11a having the second tapered surface 16 is set, it may be a different angle as long as it is an angle that rises toward the base 13, or they may be individually different angles. This is because, in the case of the second lip 11b and the third lip 11c that do not have the second tapered surface 16, it does not affect the relationship between the inclination angle θ1 and the inclination angle θ2.

[0025] Also, on the first lip 11a, the second lip 11b, and the third lip 11c of the sealing portion 11, tapered surfaces (the first tapered surface 15 and the second tapered surface 16) are not formed in the upward direction (the direction of reference numeral T2 in FIG. 1) when pulling out with respect to the direction at the time of insertion. Thereby, the sealing portion 11 of the elastic body is easily inserted into the hole portion 2. Note that, in terms of drawing creation, the large-diameter end portion of the tip that rises toward the base of the lip is an acute angle, but rounded corners are formed.

[0026] Next, the relationship between the inclination angle θ1 of the first tapered surface 15 (hereinafter simply referred to as θ1) and the inclination angle θ2 of the second tapered surface 16 (hereinafter simply referred to as θ2) will be described. θ2 is smaller than θ1, and they are in the relationship of θ1 > θ2. Furthermore, the comparison results regarding that the most preferable effective range is 2 to 14 for θ1 / θ2 will be described below.

[0027] [Evaluation by Comparison] The applicant prototyped the sealing device 1 under the conditions that θ1 > θ2, θ1 was 30°, and θ2 was 3°, measured the load (insertion load) when inserting the sealing portion 11 into the hole portion 2 and the load (pull-out load) when pulling out from the hole portion 2, and compared their maximum loads. The result of that comparison is shown in FIG. 3. From this result, a desirable numerical value was recognized that the insertion load can be reduced (made easier to insert) while maintaining the sealing performance (difficulty of coming off) of the present invention.

[0028] Regarding the comparison items in Fig. 3, the maximum loads of the insertion load (indicated by the dotted line) and the extraction load (indicated by the solid line) from the conventional example to the comparative example are described, and the comparison conditions are as follows. Also, the unit of the load is Newton (N). The "conventional example" is an example in which the second tapered surface 16 is not formed on all the lips. "Example 1" is an example in which the second tapered surface 16 is formed on the first lip 11a. "Example 2" is an example in which the second tapered surface 16 is formed on the second lip 11b. "Example 3" is an example in which the second tapered surface 16 is formed on the third lip 11c. "Comparative Example 1" is an example in which, in Example 1, θ1 / θ2 = 1.5 (θ1 = 30°, θ2 = 20°). "Comparative Example 2" is an example in which, in Example 1, θ1 / θ2 = 15 (θ1 = 30°, θ2 = 2°).

[0029] As is clear from Examples 1 to 3, by forming the second tapered surface 16 on any one of the first lip 11a to the third lip 11c of the sealing portion 11, the insertion load was significantly reduced compared to the conventional example (it became easier to insert without requiring a large force). On the other hand, although the extraction load decreased slightly, it was almost at a level without problems (the difficulty of coming off was maintained).

[0030] In particular, from the results of Example 1, it is recognized that forming the second tapered surface 16 on the first lip 11a is the most effective. That is, among Examples 1 to 3, the insertion load (98.09 N) was the lowest and the extraction load (89.10 N) was the largest.

[0031] In Comparative Example 1 (θ1 / θ2 = 1.5), it is recognized that the effect of reducing the insertion load is significantly inferior to that of the example. In Comparative Example 2 (θ1 / θ2 = 15), the extraction load significantly decreases compared to the example (it is recognized that if the extraction load decreases further, it will easily come off and is not suitable as the sealing device 1).

[0032] From the above comparison results, it was demonstrated that θ1 / θ2 in the range of about 2 to 14 is the effective range.

[0033] [Press-fit allowance] Next, the relationship between the press-fit allowance c of the present invention and the insertion direction length d of the formation range of the second tapered surface 16 will be described. In the present embodiment, as shown in FIG. 2(B), the press-fit allowance c is the press-fit direction width d of the second tapered surface 16, and the lip of the maximum diameter portion of the sealing portion 11 not provided with the second tapered surface 16 is defined as the press-fit allowance c. It is also the difference between the inner diameter b of the hole portion 2 and the maximum diameter above the third lip 11c.

[0034] The applicant prototyped the sealing device 1 under the condition that the insertion direction length d of the formation range of the second tapered surface 16 is smaller than the press-fit allowance c provided in the sealing portion 11, c > d. When the sealing device 1 was inserted into the hole portion 2, the load (insertion load) and the load when pulling out from the hole portion 2 (pull-out load) were measured, and the maximum loads (N) were compared.

[0035] In this embodiment, when the outer diameter a of the sealing portion 11 is 21.25 mm and the inner diameter b of the hole portion 2 is 19.75 mm, the press-fit allowance c is 0.75 mm according to the formula (a - b) / 2. The insertion direction length d of the formation range of the second tapered surface 16 is 0.5 mm.

[0036] In this way, by setting the insertion direction length d of the formation range of the second tapered surface 16 to be smaller than the press-fit allowance c provided in the sealing portion 11, that is, c > d, the tip of the sealing portion 11 can be inserted into the hole portion without resistance. "Comparative Example 3" in FIG. 3 is an example in Example 1 where the insertion direction length d = 0.8 mm (c < d). As a result, in Comparative Example 3 (c < d), the pull-out load is also lower and it is easier to come off compared to the example, which is not preferable. Therefore, it was confirmed that it is desirable to set c > d.

[0037] As described above, the sealing device of the present invention can reduce the insertion load for easy insertion while maintaining the sealing property of being difficult to come off.

Explanation of reference numerals

[0038] 1 Sealing device 2 Hole part 2a Hole opening 2b Edge end face of the opening of hole 2 2c Inner wall of the hole 11 Sealing part 11a First lip 11b Second lip 11c Third lip 12 Press - in prevention part 13 Base part 14 Knob part 15 First tapered surface 16 Second tapered surface T axis

Claims

Claim 1 A sealing device that presses a lip against the inner wall of a hole by elastic force to seal the hole, A sealing portion having an inverted frustum shape with a first tapered surface extending from the minimum diameter surface portion to the maximum diameter surface portion is integrally formed in a plurality of stages, At least one sealing portion includes a second tapered surface that is continuously formed from the first tapered surface and has an inclination angle different from that of the first tapered surface, A sealing device characterized in that when the inclination angle of the first tapered surface is θ1 and the inclination angle of the second tapered surface is θ2, the relationship θ1 > θ2 is satisfied. Claim 2 The sealing device according to claim 1, characterized in that the ratio θ1 / θ2 of the inclination angles of θ1 and θ2 is 2 to 14. Claim 3 The sealing device according to claim 1 or 2, characterized in that when the press-fitting direction width of the second tapered surface is d and the press-fitting margin of the lip at the maximum diameter surface portion of the sealing portion not provided with the second tapered surface is c, the relationship c > d is satisfied.

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