Sealing device and reciprocating mechanism

Abstract

This reciprocating mechanism comprises: a first member that has an inner peripheral surface; a second member that is inserted radially inward of the inner peripheral surface and moves in the axial direction with respect to the first member; and a sealing device that seals an annular gap formed between the first member and the second member. An outer peripheral surface of the second member is provided with an annular groove, and the annular groove includes an annular first groove part, and at least one second groove part having a depth smaller than the depth of the first groove part. The sealing device comprises a body part, a lip part protruding in the axial direction from the body part, and at least one protrusion part protruding in a second protrusion direction opposite to a first protrusion direction in which the lip part protrudes in the axial direction from the body part. The body part and the lip part are disposed in the first groove part, and the at least one protrusion part is disposed in the at least one second groove part.

Description

Sealing device and reciprocating mechanism

[0001] The present disclosure relates to a sealing device and a reciprocating mechanism.

[0002] 2. Description of the Related Art There is known a sealing device that is disposed in a groove provided in one of two members that move relative to one another, and that slidably fits tightly to the other member.

[0003] Patent Document 1 discloses a sealing system having a housing, a shaft, and a seal disposed therebetween. The shaft has an annular groove formed on its outer circumferential surface. The seal is disposed in the annular groove. The seal prevents fluid from escaping.

[0004] The seal is an annular body having a V-shaped cross section, the apex of which extends radially outward of the annular groove and engages the inner surface of the housing, and the V-shaped cross section allows for a better seal against the wall of the annular groove than a square cross section would.

[0005] Japanese Patent Application Laid-Open No. 2021-006743

[0006] The seals placed between the housing and the shaft may be installed in the wrong position in the annular groove, which may result in the seal not sealing properly and causing the seal to open, resulting in leakage of fluid or other substances.

[0007] In order to solve the above problems, a reciprocating mechanism according to one aspect of the present disclosure comprises: a first member having an inner circumferential surface; a second member inserted radially inside the inner circumferential surface and moving axially relative to the first member; and a sealing device that seals an annular gap formed between the first member and the second member, wherein an annular groove is provided on the outer circumferential surface of the second member, the annular groove comprising: an annular first groove portion; and at least one second groove portion connected to the first groove portion and having a depth smaller than that of the first groove portion, and the sealing device comprises: a main body portion; a lip portion protruding from the main body portion in the axial direction; and at least one protrusion portion protruding from the main body portion in a second protrusion direction opposite to a first protrusion direction in which the lip portion protrudes in the axial direction, wherein the main body portion and the lip portion are arranged in the first groove portion, and the at least one protrusion portion is arranged in the at least one second groove portion.

[0008] A sealing device according to one aspect of the present disclosure is a sealing device that seals an annular gap formed between a first member having an inner circumferential surface and a second member that is inserted radially inside the inner circumferential surface and moves axially relative to the first member, and comprises a main body portion, a lip portion that protrudes from the main body portion in the axial direction, and at least one protrusion portion that protrudes from the main body portion in a second protrusion direction opposite to a first protrusion direction in which the lip portion protrudes in the axial direction, and the at least one protrusion portion determines the arrangement direction of the lip portion relative to the main body portion.

[0009] According to the present disclosure, it is possible to make it difficult for the sealing device to be placed incorrectly, thereby preventing leakage of the object to be sealed.

[0010] Fig. 3 is a cross-sectional view schematically showing a part of the reciprocating mechanism of the first embodiment. Fig. 4 is an enlarged view of the annular groove and the sealing device shown in Fig. 1. Fig. 5 is a perspective view of the sealing device shown in Fig. 2. Fig. 6 is a view showing an example of incorrect placement of the sealing device shown in Fig. 2. Fig. 7 is a view showing a sealing device of a comparative example. Fig. 8 is a view showing a sealing device of a comparative example. Fig. 9 is a perspective view of a sealing device of a modified example.

[0011] Preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings. Note that the dimensions or scale of each part in the drawings may differ from the actual dimensions, and some parts are shown schematically to facilitate understanding. Furthermore, the scope of the present disclosure is not limited to the following forms unless otherwise specified in the following description.

[0012] A. Embodiments 1. Reciprocating mechanism 100 Fig. 1 is a cross-sectional view schematically showing a portion of a reciprocating mechanism 100 according to a first embodiment. The reciprocating mechanism 100 shown in Fig. 1 is used, for example, as a power source for machinery such as general industrial machinery. The reciprocating mechanism 100 shown in Fig. 1 has a first member 1, a second member 2, and a sealing device 4. The second member 2 has an axis A1.

[0013] The first member 1 is a housing having an inner circumferential surface 11. The inner circumferential surface 11 is annular.

[0014] The second member 2 is a piston inserted radially inside the inner peripheral surface 11 of the first member 1 and reciprocates axially relative to the first member 1. The second member 2 is, for example, cylindrical. The outer diameter of the second member 2 is slightly smaller than the inner diameter of the first member 1. Therefore, an annular gap is formed between the first member 1 and the second member 2. In addition, an annular groove 20 is formed in the outer peripheral surface 21.

[0015] The sealing device 4 is a packing that seals the annular gap that exists between the first member 1 and the second member 2. The sealing device 4 is disposed in the annular groove 20. The sealing device 4 is in close contact with the inner circumferential surface 11 of the first member 1 and the outer circumferential surface 21 of the second member 2, and slides against the inner circumferential surface 11 of the first member 1 in response to the reciprocating movement of the second member 2 in the axial direction.

[0016] In this reciprocating mechanism 100, pressure is applied to the sealing device 4 in the direction of arrow A0 by the object to be sealed. This object to be sealed is sealed by the sealing device 4. The sealing device 4 prevents the object to be sealed from flowing from the space on the left side of the sealing device 4 into the space on the right side.

[0017] 2. Annular Groove 20 and Sealing Device 4 FIG. 2 is an enlarged view of the annular groove 20 and sealing device 4 shown in FIG.

[0018] 2, the annular groove 20 is a recess formed in the outer circumferential surface 21. The annular groove 20 has a first groove portion 201 and a second groove portion 202. Each of the first groove portion 201 and the second groove portion 202 has an annular shape.

[0019] The first groove portion 201 has a bottom portion 2011 and side portions 2012 and 2013. The bottom portion 2011 is a surface along the axis A1. The side portions 2012 and 2013 are each a surface perpendicular to the axis A1. The side portions 2012 and 2013 face each other. The groove formed in the side portion 2013 is the second groove portion 202.

[0020] The second groove portion 202 has a bottom portion 2021 and a side portion 2022. The bottom portion 2021 is a surface along the axis A1. The bottom portion 2021 is connected to the side portion 2022. The side portion 2022 is a surface perpendicular to the axis A1. The side portion 2022 faces the side portion 2012. The bottom portion 2021 is located radially outward of the bottom portion 2011.

[0021] The second groove portion 202 is provided at a position farther from the object to be sealed than the first groove portion 201. The second groove portion 202 is connected to the first groove portion 201. The depth W2 of the second groove portion 202 is smaller than the depth W1 of the first groove portion 201. Note that the depths W1 and W2 are lengths along the radial direction. The width of the second groove portion 202 is smaller than the width of the first groove portion 201. The width is the length in the axial direction. The second groove portion 202 is a smaller recess than the first groove portion 201. Therefore, the volume of the space formed by the second groove portion 202 is smaller than the volume of the space formed by the first groove portion 201.

[0022] Fig. 3 is a perspective view of the sealing device 4 shown in Fig. 2. As shown in Fig. 2 and Fig. 3, the sealing device 4 has a main body portion 40, a lip portion 41, and a protrusion portion 42. The main body portion 40 is a thick portion located in the center of the sealing device 4. The main body portion 40 is annular.

[0023] As shown in Fig. 2, the lip portion 41 protrudes in the axial direction from the main body portion 40. Specifically, the first protruding direction of the lip portion 41 is the X1 direction. The lip portion 41 adheres closely to the inner circumferential surface 11 of the first member 1 and the outer circumferential surface 21 of the second member 2, and this adhesion prevents leakage of the sealed object. The lip portion 41 prevents the sealed object from moving from the space to the right of the sealing device 4 in Fig. 2 to the space to the left.

[0024] The lip portion 41 has an outer lip 411 and an inner lip 412. The outer lip 411 and the inner lip 412 protrude in a first protruding direction and are spaced apart from each other. The outer lip 411 and the inner lip 412 are each annular. The inner lip 412 is located radially inward of the outer lip 411. The outer lip 411 contacts the inner circumferential surface 11 of the first member 1, and the inner lip 412 contacts the outer circumferential surface 21 of the second member 2. The sealing device 4 seals the gap between the first member 1 and the second member 2 by generating surface pressure on the first member 1 and the second member 2.

[0025] The protrusion 42 protrudes in a second protrusion direction opposite to the first protrusion direction in which the lip portion 41 protrudes from the main body portion 40 in the axial direction. The second protrusion direction of the protrusion 42 is the X2 direction. From another perspective, the protrusion 42 protrudes from the bottom of the main body portion 40. The protrusion 42 has an annular shape. The protrusion 42 is located radially outward of the inner lip 412.

[0026] As described above, the sealing device 4 is disposed in the annular groove 20. The main body 40 and the lip 41 of the sealing device 4 are disposed in the first groove 201. The protrusion 42 of the sealing device 4 is disposed in the second groove 202. The protrusion 42 and the second groove 202 function as a determining portion for determining the arrangement direction of the sealing device 4. The provision of the protrusion 42 and the second groove 202 makes it possible to prevent the sealing device 4 from being assembled in an incorrect position in the annular groove 20, compared to when the protrusion 42 and the second groove 202 are not provided. Therefore, the sealing device 4 can be correctly disposed inside the annular groove 20, and good sealing by the sealing device 4 can be stably performed. This prevents the sealing device 4 from opening and causing leakage of the sealed object. From this perspective, the protrusion 42 functions as a determining portion for determining the arrangement direction of the lip 41 relative to the main body 40 in the axial direction.

[0027] 4 is a diagram showing an example of an incorrect placement of the sealing device 4 shown in FIG. 2 . As shown in FIG. 4 , if the sealing device 4 is incorrectly placed inside the annular groove 20, the placement of the sealing device 4 shown in FIG. 4 is assumed. However, if the sealing device 4 is placed in this manner, there is no space to place the protrusion 42, and the worker can notice the incorrect placement of the sealing device 4. Alternatively, if the sealing device 4 is placed in this manner, it becomes difficult to insert the second member 2 into the first member 1, and the worker can notice the incorrect placement. Furthermore, since the protrusion 42 is placed in the second groove portion 202 of the first member 1, the incorrect placement of the sealing device 4 is easily noticed during the assembly inspection process.

[0028] As shown in Figure 3, when placing the sealing device 4 in the annular groove 20, by placing the protrusion 42 in the second groove portion 202, the sealing device 4 can be correctly placed in the annular groove 20. Therefore, it is less likely that an operator will make a mistake in placement.

[0029] 5 and 6 each show a sealing device 4X of a comparative example. The first member 1X shown in FIG. 5 has an annular groove 20X. The annular groove 20X does not have the second groove portion 202 shown in FIG. 2. The sealing device 4X also has a main body 40X and two outer peripheral lips 411X and an inner peripheral lip 412X. However, the sealing device 4X does not have a protrusion 42.

[0030] For this sealing device 4X, the correct arrangement is shown in Figure 5, and the incorrect arrangement is shown in Figure 6. If the second groove portion 202 and the protrusion portion 42 were not provided, the worker would not notice the incorrect arrangement of the sealing device 4X and may end up placing it in the arrangement shown in Figure 6 instead of the arrangement shown in Figure 5. As a result, the adhesion force of the sealing device 4X to the first member 1X would be smaller than the pressure of the object to be sealed, making it difficult to prevent leakage from the object to be sealed.

[0031] In contrast, in this embodiment, as shown in Fig. 2, the second groove portion 202 is provided in the annular groove 20, and the protrusion 42 is provided on the sealing device 4. Therefore, by arranging the protrusion 42 in the second groove portion 202, it is difficult to make a mistake in the placement of the sealing device 4. Therefore, leakage of the object to be sealed can be prevented.

[0032] As described above, the lip portion 41 has an outer lip 411 and an inner lip 412 aligned in the radial direction. The outer lip 411 adheres closely to the inner circumferential surface 11 of the first member 1, and the inner lip 412 adheres closely to the outer circumferential surface 21 of the second member 2, and this adhesion prevents leakage of the sealed material. The lip portion 41 can effectively prevent leakage of the sealed material.

[0033] The configuration of the lip portion 41 is not limited to this, and other configurations may be used. The number of lips that the lip portion 41 has may be one, or may be three or more.

[0034] Furthermore, the protrusion 42 is located radially outward of the inner lip 412. This makes it easier for the worker to place the sealing device 4 in the annular groove 20. In addition, it is easier to place the protrusion 42 in the second groove portion 202. This makes it less likely that the sealing device 4 will be placed incorrectly.

[0035] Furthermore, the radial position of the connection portion between the protrusion 42 and the main body 40 overlaps with the radial position of the connection portion between the outer lip 411 and the main body 40. In other words, these positions are approximately the same. "Same" means that they are essentially the same, and some manufacturing error is acceptable. Providing the protrusion 42 in such a position makes it easy for the worker to place the sealing device 4 in the annular groove 20. In addition, it is easy to place the protrusion 42 in the second groove portion 202. Therefore, it is less likely that the sealing device 4 will be placed incorrectly.

[0036] The radial position of the connection portion between the protrusion 42 and the main body 40 does not have to overlap with the radial position of the connection portion between the outer lip 411 and the main body 40 .

[0037] Furthermore, the protrusion length T2 of the protrusion 42 in the second protrusion direction from the main body 40 is shorter than the protrusion length T1 of the outer peripheral lip 411 in the first protrusion direction from the main body 40. This reduces the risk of confusing the protrusion 42 with the outer peripheral lip 411 compared to when the length T2 is longer than the length T1. This makes it even less likely that the protrusion 42 will be misaligned with respect to the second groove 202.

[0038] The length T2 may be equal to or greater than the length T1.

[0039] Furthermore, the position of the tip 4111 of the outer lip 411 is located radially outward of the position of the tip 421 of the protrusion 42. This increases the adhesion force of the outer lip 411 to the first member 1, and also reduces the risk of the protrusion 42 excessively abutting against the second member 2, which could reduce the sliding ability of the sealing device 4 relative to the second member 2.

[0040] In particular, it is preferable that the protrusion 42 does not abut against the second member 2. By not having the protrusion 42 abut against the second member 2, it is possible to prevent a decrease in the slidability of the sealing device 4 relative to the second member 2 due to the protrusion 42 abutting against the second member 2. Note that the protrusion 42 may be on the second member 2. Furthermore, from the viewpoint of preventing a decrease in slidability, it is preferable that the protrusion 42 does not abut against the first member 1, but it may be in contact with the first member 1 to the extent that this does not cause a decrease in slidability.

[0041] Moreover, the protrusion 42 preferably has a tapered shape that narrows as it gets farther away from the main body 40. The tapered shape makes it possible to prevent a decrease in the sliding ability of the sealing device 4 relative to the second member 2 when the protrusion 42 abuts against the second member 2.

[0042] Furthermore, when the protrusions 42 are annular, it is preferable that the number of the protrusions 42 is less than the number of lips of the lip portion 41. In this way, the protrusions 42 and the lip portion 41 are not confused, and the sealing device 4 is less likely to be misplaced.

[0043] B. Modifications The first embodiment exemplified above may be modified in various ways. Specific modifications that may be applied to the first embodiment are exemplified below. Two or more modifications arbitrarily selected from the following examples may be combined as appropriate to the extent that they are not mutually contradictory.

[0044] In the first embodiment, the number of the protrusions 42 is one, and the protrusions 42 are annular. However, the number and shape of the protrusions 42 are not limited to these.

[0045] Fig. 7 is a perspective view of a modified sealing device 4A. The modified sealing device 4A shown in Fig. 7 has a plurality of protrusions 42. The protrusions 42 are spaced apart from one another. Although not shown, the annular groove 20 has a plurality of second grooves 202 that are spaced apart from one another. The second grooves 202 are provided corresponding to the protrusions 42. Specifically, the protrusions 42 are arranged in a one-to-one relationship with the second grooves 202.

[0046] As with the first embodiment, this modification also reduces the chance of an operator misplacing the sealing device 4A. This prevents leakage of the sealed object. Furthermore, compared to the first embodiment, the risk of confusing the protrusion 42 with the lip 41 is reduced, making it less likely that the sealing device 4A will be misplaced.

[0047] While the present disclosure has been described above based on preferred embodiments, the present disclosure is not limited to the above-described embodiments. Furthermore, the configuration of each part of the present disclosure can be replaced with any configuration that exhibits the same function as the above-described embodiments, and any configuration can be added.

[0048] C. Supplementary Notes The following aspects, for example, can be understood from the above embodiment and modified examples.

[0049] A first aspect of a reciprocating mechanism that is a preferred example of the present disclosure comprises: a first member having an inner circumferential surface; a second member that is inserted radially inside the inner circumferential surface and moves in the axial direction relative to the first member; and a sealing device that seals an annular gap formed between the first member and the second member, wherein an annular groove is provided on the outer circumferential surface of the second member, and the annular groove comprises an annular first groove portion and at least one second groove portion that is connected to the first groove portion and has a depth smaller than that of the first groove portion, and the sealing device comprises a main body portion, a lip portion that protrudes from the main body portion in the axial direction, and at least one protrusion portion that protrudes from the main body portion in a second protrusion direction opposite to a first protrusion direction in which the lip portion protrudes in the axial direction, and the main body portion and the lip portion are arranged in the first groove portion, and the at least one protrusion portion is arranged in the at least one second groove portion.

[0050] Such a reciprocating mechanism makes it difficult for the sealing device to be placed incorrectly, thereby preventing leakage of the object to be sealed by the sealing device.

[0051] In a second aspect, which is a preferred example of the first aspect, the at least one protrusion is a plurality of protrusions spaced apart from one another, the at least one second groove is a plurality of second grooves spaced apart from one another, and the plurality of protrusions are arranged in a one-to-one relationship with the plurality of second grooves.

[0052] This reciprocating mechanism also makes it difficult for the sealing device to be positioned incorrectly, thereby preventing leakage of the object to be sealed by the sealing device.

[0053] In a third aspect, which is a preferred example of the first aspect, the lip portion has an outer lip and an inner lip that is spaced apart from the outer lip and positioned radially inward from the outer lip, and the at least one protrusion portion is positioned radially outward from the inner lip.

[0054] With this reciprocating mechanism, the outer lip is in close contact with the inner circumferential surface of the first member, and the inner lip is in close contact with the outer circumferential surface of the second member, and this close contact prevents leakage of the sealed material. This lip portion effectively prevents leakage of the sealed material. Furthermore, since the protrusion is located radially outward of the inner lip, the worker can easily place the sealing device in the annular groove. Additionally, the protrusion can be easily placed in the second groove. Therefore, incorrect placement of the sealing device is less likely to occur.

[0055] In a fourth aspect, which is a preferred example of the third aspect, the radial position of the connection portion between the at least one protrusion and the main body portion overlaps with the radial position of the connection portion between the outer lip and the main body portion.

[0056] This reciprocating mechanism allows the operator to easily place the sealing device in the annular groove and also to easily place the protrusion in the second groove, thereby reducing the likelihood of incorrect placement of the sealing device.

[0057] In a fifth aspect, which is a preferred example of the third aspect, the protruding length of the at least one protrusion from the main body portion in the second protruding direction is shorter than the protruding length of the outer lip from the main body portion in the first protruding direction.

[0058] This reciprocating mechanism can reduce the risk of confusing the protrusion with the outer lip, making it even more unlikely that the protrusion will be misaligned with respect to the second groove.

[0059] In a sixth aspect which is a preferred example of the third aspect, a tip of the outer peripheral lip is positioned radially outward of a tip of the at least one protrusion.

[0060] Such a reciprocating mechanism can increase the adhesion force of the outer lip to the first member, and can also reduce the risk of the protrusion contacting the first member excessively, thereby reducing the sliding ability of the sealing device relative to the first member.

[0061] 1...first member, 1X...first member, 2...second member, 4...sealing device, 4A...sealing device, 4X...sealing device, 20...annular groove, 20X...annular groove, 11...inner surface, 2X...second member, 21...outer surface, 40...main body portion, 40X...main body portion, 41...lip portion, 42...protrusion portion, 100...reciprocating mechanism, 201...first groove portion, 202...second groove portion, 411...outer lip portion, 412...inner lip portion, 421...tip, 2011...bottom portion, 2012...side portion, 2013...side portion, 2021...bottom portion, 2022...side portion, 4121...tip portion, A0...arrow, A1...axis, W1...depth, W2...depth, T1...height, T2...height.

Claims

1. A reciprocating mechanism comprising: a first member having an inner peripheral surface; a second member inserted radially inward of the inner peripheral surface and movable axially relative to the first member; and a sealing device for sealing an annular gap formed between the first member and the second member, wherein the outer peripheral surface of the second member is provided with an annular groove, the annular groove comprising: a first annular groove portion; and at least one second groove portion connected to the first groove portion and having a depth smaller than that of the first groove portion, the sealing device comprising: a main body portion; a lip portion protruding from the main body portion in the axial direction; and at least one protrusion portion protruding from the main body portion in a second protrusion direction in the axial direction that is opposite to a first protrusion direction in which the lip portion protrudes, the main body portion and the lip portion being arranged in the first groove portion, and the at least one protrusion portion being arranged in the at least one second groove portion.

2. A reciprocating mechanism according to claim 1, wherein the at least one protrusion is a plurality of protrusions spaced apart from one another, the at least second groove is a plurality of second grooves spaced apart from one another, and the plurality of protrusions are arranged in a one-to-one relationship with the plurality of second grooves.

3. A reciprocating mechanism as set forth in claim 1, wherein the lip portion has an outer lip and an inner lip spaced apart from the outer lip and positioned radially inward of the outer lip, and the at least one protrusion is positioned radially outward of the inner lip.

4. A reciprocating mechanism according to claim 3, wherein the radial position of the connection portion between said at least one protrusion and said main body overlaps with the radial position of the connection portion between said outer lip and said main body.

5. A reciprocating mechanism according to claim 3, wherein the length of projection of said at least one protrusion from said main body in said second projection direction is shorter than the length of projection of said outer lip from said main body in said first projection direction.

6. A reciprocating mechanism according to claim 3, wherein the tip of the outer lip is positioned radially outward of the tip of the at least one protrusion.

7. A sealing device that seals an annular gap formed between a first member having an inner peripheral surface and a second member that is inserted radially inside the inner peripheral surface and moves axially relative to the first member, comprising: a main body portion; a lip portion that protrudes from the main body portion in the axial direction; and at least one protrusion portion that protrudes from the main body portion in a second protrusion direction opposite to a first protrusion direction in which the lip portion protrudes in the axial direction, wherein the at least one protrusion portion determines the arrangement direction of the lip portion relative to the main body portion.

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