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

Technical Field

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

Background Art

[0002] A sealing device is known that is arranged in a groove provided in one of two relatively moving members and slidably adheres to the other member.

[0003] Patent Document 1 discloses a sealing system having a housing, a shaft, and a seal arranged therebetween. An annular groove is provided on the outer peripheral surface of the shaft. The seal is arranged in the annular groove. The seal prevents the discharge of fluid.

[0004] Also, the seal is an annular body having a V-shaped cross section. The top of the V-shaped cross section extends radially outward of the annular groove and engages with the inner surface of the housing. By having a V-shaped cross section, a better seal against the wall of the annular groove is enabled compared to the case of a square cross section.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Such a seal arranged between a housing and a shaft may be assembled in an incorrect arrangement in the annular groove. If the seal is not correctly installed, good sealing by the seal cannot be achieved, and there is a risk that the seal will open and leakage of an object such as fluid will occur.

Means for Solving the Problems

[0007] 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 inward of the inner circumferential surface and moving 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 an annular groove is provided on the outer circumferential surface of the second member, the annular groove comprises an annular first groove portion and at least one second groove portion connected to the first groove portion and having a depth smaller than the depth of the first groove portion, the sealing device comprises a main body portion, a lip portion projecting axially from the main body portion, and at least one projection portion projecting axially from the main body portion in a second projection direction opposite to the first projection direction from which the lip portion projects, the main body portion and the lip portion are arranged in the first groove portion, and the at least one projection 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 for sealing an annular gap formed between a first member having an inner circumferential surface and a second member inserted radially inward of the inner circumferential surface and moving axially relative to the first member, comprising a main body, a lip portion projecting axially from the main body, and at least one projection projecting axially from the main body in a second projection direction opposite to the first projection direction in which the lip portion projects axially, wherein the at least one projection defines the orientation of the lip portion relative to the main body. [Effects of the Invention]

[0009] According to this disclosure, it is possible to prevent leakage of the sealed object by making it less likely for the sealing device to be misplaced. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing a part of the reciprocating mechanism of the first embodiment. [Figure 2] Figure 1 is an enlarged view of the annular groove and sealing device shown. [Figure 3] Figure 2 is a perspective view of the sealed device. [Figure 4]Figure 2 shows an example of an incorrect placement of the sealing device. [Figure 5] This figure shows a comparative example of a sealing device. [Figure 6] This figure shows a comparative example of a sealing device. [Figure 7] This is a perspective view of a modified sealing device. [Modes for carrying out the invention]

[0011] Preferred embodiments of this disclosure will be described below with reference to the attached drawings. Note that the dimensions and scale of parts in the drawings may differ from actual dimensions as appropriate, and some parts are shown schematically for ease of understanding. Furthermore, the scope of this disclosure is not limited to the following embodiments unless otherwise stated in the following description.

[0012] A. Embodiment 1. Reciprocating mechanism 100 Figure 1 is a schematic cross-sectional view showing a part of the reciprocating mechanism 100 of the first embodiment. The reciprocating mechanism 100 shown in Figure 1 is used, for example, as a power source for machinery such as general industrial machinery. The reciprocating mechanism 100 shown in Figure 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 component 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 inward from the inner circumferential 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. As a result, an annular gap is formed between the first member 1 and the second member 2. In addition, an annular groove 20 is provided on the outer circumferential surface 21.

[0015] The sealing device 4 is a packing that seals an annular gap existing between the first member 1 and the second member 2. The sealing device 4 is disposed in the annular groove 20. Also, the sealing device 4 adheres to the inner peripheral surface 11 of the first member 1 and the outer peripheral surface 21 of the second member 2, and slides with respect to the inner peripheral surface 11 of the first member 1 according to the second member 2 that reciprocates in the axial direction.

[0016] In such a reciprocating mechanism 100, a pressure in the direction along the arrow A0 is applied to the sealing device 4 by the object to be sealed. The 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 the sealing device 4 shown in FIG. 1.

[0018] As shown in FIG. 2, the annular groove 20 is a recess formed in the outer peripheral 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 is annular.

[0019] The first groove portion 201 has a bottom portion 20**11**, side portions 20**12** and 20**13**. The bottom portion 20**11** is a surface along the axis A1. Each of the side portions 20**12** and 20**13** is a surface orthogonal to the axis A1. The side portions 20**12** and 20**13** face each other. The groove formed in the side portion 20**13** is the second groove portion 202.

[0020] The second groove portion 202 has a bottom portion 20**21** and a side portion 20**22**. The bottom portion 20**21** is a surface along the axis A1. The bottom portion 20**21** is connected to the side portion 20**22**. The side portion 20**22** is a surface orthogonal to the axis A1. The side portion 20**22** faces the side portion 20**12**. The bottom portion 20**21** is located radially outside the bottom portion 20**11**.

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

[0022] Figure 3 is a perspective view of the sealing device 4 shown in Figure 2. As shown in Figures 2 and 3, the sealing device 4 has a main body portion 40, a lip portion 41, and a projection portion 42. The main body portion 40 is a thick portion located in the central part of the sealing device 4. The main body portion 40 is annular in shape.

[0023] As shown in Figure 2, the lip portion 41 protrudes axially 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 tightly 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 object to be sealed. This lip portion 41 prevents the object to be sealed from moving from the space to the right of the sealing device 4 in Figure 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 the first projection direction and are spaced apart from each other. Each of the outer lip 411 and the inner lip 412 is annular. The inner lip 412 is located radially inward from the outer lip 411. The outer lip 411 is in contact with the inner surface 11 of the first member 1, and the inner lip 412 is in contact with the outer 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 projection 42 protrudes in a second projection direction opposite to the first projection direction in which the lip portion 41 protrudes axially from the main body portion 40. The second projection direction of the projection 42 is the X2 direction. Alternatively, the projection 42 protrudes from the bottom of the main body portion 40. The projection 42 is annular. The projection 42 is located radially outward from the inner circumferential lip 412.

[0026] As described above, the sealing device 4 is positioned in the annular groove 20. The main body portion 40 and the lip portion 41 of the sealing device 4 are positioned in the first groove portion 201. The projection portion 42 of the sealing device 4 is positioned in the second groove portion 202. The projection portion 42 and the second groove portion 202 function as regulating portions that define the positioning direction of the sealing device 4. By providing the projection portion 42 and the second groove portion 202, it is possible to prevent incorrect assembly of the sealing device 4 in the annular groove 20 compared to when they are not provided. Therefore, the sealing device 4 can be correctly positioned inside the annular groove 20, and good sealing by the sealing device 4 can be stably achieved. Thus, it is possible to prevent the sealing device 4 from opening and causing leakage of the sealed object. From this viewpoint, the projection portion 42 functions as a regulating portion that defines the positioning direction of the lip portion 41 relative to the main body portion 40 in the axial direction.

[0027] Figure 4 shows an example of incorrect placement of the sealing device 4 shown in Figure 2. As shown in Figure 4, if the sealing device 4 is incorrectly placed inside the annular groove 20, it is expected to be placed as shown in Figure 4. However, with this placement, there is no space to place the projection 42, and the worker can notice the incorrect placement of the sealing device 4. Alternatively, with this placement, it becomes difficult to insert the second member 2 into the first member 1, so the worker can notice the incorrect placement. Furthermore, because the projection 42 is placed in the second groove 202 of the first member 1, it is easy to notice the incorrect placement of the sealing device 4 during the assembly inspection process.

[0028] As shown in Figure 3, when placing the sealing device 4 into the annular groove 20, the projection 42 is positioned in the second groove 202, allowing the sealing device 4 to be correctly positioned in the annular groove 20. Therefore, errors in placement by the worker are unlikely to occur.

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

[0030] In the sealing device 4X, Figure 5 shows the correct configuration, while Figure 6 shows the incorrect configuration. If the second groove 202 and projection 42 are not provided, the operator may not notice the incorrect configuration of the sealing device 4X and may configure it as shown in Figure 6 instead of Figure 5. As a result, the adhesion force of the sealing device 4X to the first member 1X becomes smaller than the pressure exerted by the object being sealed, making it difficult to prevent leakage of the object being sealed.

[0031] In contrast, in this embodiment, as shown in Figure 2, a second groove 202 is provided in the annular groove 20, and a projection 42 is provided on the sealing device 4. Therefore, by positioning the projection 42 in the second groove 202, it is less likely that the sealing device 4 will be mispositioned. Thus, leakage of the object to be sealed can be prevented.

[0032] Furthermore, as described above, the lip portion 41 has an outer peripheral lip 411 and an inner peripheral lip 412 arranged radially. The outer peripheral lip 411 adheres closely to the inner peripheral surface 11 of the first member 1, and the inner peripheral lip 412 adheres closely to the outer peripheral surface 21 of the second member 2, and this adhesion force prevents leakage of the material to be sealed. With such a lip portion 41, leakage of the material to be sealed can be effectively suppressed.

[0033] The configuration of the lip portion 41 is not limited to this and may be configured in other ways. The number of lips on the lip portion 41 may be one or three or more.

[0034] Furthermore, the projection 42 is located radially outward from the inner lip 412. This makes it easier for the operator to position the sealing device 4 in the annular groove 20. In addition, it is easier to position the projection 42 in the second groove 202. Therefore, it is less likely that the sealing device 4 will be mispositioned.

[0035] Furthermore, the radial position of the connection between the projection 42 and the main body 40 coincides with the radial position of the connection between the outer lip 411 and the main body 40. In other words, these positions are almost the same. By "same," it is sufficient that they are substantially the same, and some manufacturing tolerances are acceptable. The placement of the projection 42 in this position makes it easier for the operator to position the sealing device 4 in the annular groove 20. In addition, it makes it easier to position the projection 42 in the second groove 202. Therefore, it is less likely that the sealing device 4 will be misplaced.

[0036] Furthermore, the radial position of the connection portion between the projection 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 projection length T2 of the projection 42 in the second projection direction from the main body 40 is shorter than the projection length T1 of the outer peripheral lip 411 in the first projection direction from the main body 40. Therefore, compared to the case where length T2 is longer than length T1, the risk of confusing the projection 42 with the outer peripheral lip 411 can be reduced. This makes it even less likely to misplace the projection 42 with respect to the second groove 202.

[0038] Note that length T2 may be greater than or equal to length T1.

[0039] Furthermore, the position of the tip 4111 of the outer peripheral lip 411 is radially outward from the position of the tip 421 of the projection 42. This allows for increased adhesion of the outer peripheral lip 411 to the first member 1, and also suppresses the risk of reduced sliding performance of the sealing device 4 against the second member 2 due to excessive contact of the projection 42 with the second member 2.

[0040] In particular, it is preferable that the projection 42 does not come into contact with the second member 2. By preventing the projection 42 from coming into contact with the second member 2, it is possible to prevent a decrease in the sliding performance of the sealing device 4 relative to the second member 2 due to the projection 42 coming into contact with the second member 2. The projection 42 may also be the second member 2. Furthermore, from the viewpoint of reducing sliding performance, it is preferable that the projection 42 does not come into contact with the first member 1, but it may come into contact with the first member 1 to an extent that does not cause a decrease in sliding performance.

[0041] Furthermore, it is preferable that the projection 42 is tapered, becoming narrower as it moves away from the main body 40. The tapered shape prevents a decrease in the sliding performance of the sealing device 4 against the second member 2 by allowing the projection 42 to contact the second member 2.

[0042] Furthermore, if the projection 42 is annular, it is preferable that the number of projections 42 is less than the number of lips on the lip portion 41. This makes it less likely that the projections 42 and the lip portion 41 will be confused and that the sealing device 4 will be misplaced.

[0043] B. Variations The first embodiment illustrated above can be modified in various ways. Specific examples of modifications that can be applied to the aforementioned first embodiment are given below. Two or more embodiments arbitrarily selected from the following examples can be combined as appropriate, to the extent that they do not contradict each other.

[0044] In the first embodiment, there was one projection 42, and the projection 42 was annular in shape. However, the number and shape of the projection 42 are not limited to these.

[0045] Figure 7 is a perspective view of a modified sealing device 4A. The modified sealing device 4A shown in Figure 7 has a plurality of protrusions 42. The plurality of protrusions 42 are spaced apart from each other. In this case, although not shown, the annular groove 20 has a plurality of second grooves 202 that are spaced apart from each other. The plurality of second grooves 202 are provided corresponding to the plurality of protrusions 42. Specifically, the plurality of protrusions 42 are arranged in a one-to-one ratio with respect to the plurality of second grooves 202.

[0046] Even with these modifications, the risk of operators misplacing the sealing device 4A can be reduced, similar to the first embodiment. Therefore, leakage of the object to be sealed can be prevented. Furthermore, compared to the first embodiment, there is less risk of confusing the projection 42 with the lip 41, and thus, misplacing the sealing device 4 is less likely to occur.

[0047] Although the present disclosure has been described above based on preferred embodiments, the present disclosure is not limited to the embodiments described above. Furthermore, the configuration of each part of the present disclosure can be replaced with any configuration that performs a similar function to the embodiments described above, and any configuration can be added.

[0048] C. Addendum From the above embodiments or modifications, for example, the following embodiments can be understood.

[0049] A reciprocating mechanism according to a first embodiment, which is a preferred example of the present disclosure, comprises a first member having an inner circumferential surface, a second member inserted radially inward of the inner circumferential surface and moving 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 an annular groove is provided on the outer circumferential surface of the second member, the annular groove comprises an annular first groove portion and at least one second groove portion connected to the first groove portion and having a depth smaller than the depth of the first groove portion, the sealing device comprises a main body portion, a lip portion projecting axially from the main body portion, and at least one projection portion projecting axially from the main body portion in a second projection direction opposite to the first projection direction in which the lip portion projects, the main body portion and the lip portion are arranged in the first groove portion, and the at least one projection 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 misplaced. Therefore, it is possible to prevent leakage of the object being sealed by the sealing device.

[0051] In a second embodiment, which is a preferred example of the first embodiment, the at least one projection is a plurality of projections spaced apart from each other, the at least one second groove is a plurality of second grooves spaced apart from each other, and the plurality of projections are arranged in a one-to-one ratio with respect to the plurality of second grooves.

[0052] This reciprocating mechanism also makes it difficult for the sealing device to be misplaced. Therefore, it is possible to prevent leakage of the object being sealed by the sealing device.

[0053] In a third embodiment, which is a preferred example of the first embodiment, the lip portion has an outer peripheral lip and an inner peripheral lip spaced apart from the outer peripheral lip and located radially inward from the outer peripheral lip, and the at least one projection is located radially outward from the inner peripheral lip.

[0054] With this reciprocating mechanism, the outer lip adheres closely to the inner surface of the first member, and the inner lip adheres closely to the outer surface of the second member, and this adhesion prevents leakage of the sealed material. With this lip portion, leakage of the sealed material can be effectively prevented. Furthermore, because the projection is located radially outward from the inner lip, it is easier for the operator to position the sealing device in the annular groove. In addition, it is easier to position the projection in the second groove. Therefore, it is less likely that the sealing device will be positioned incorrectly.

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

[0056] With this reciprocating mechanism, the operator can easily position the sealing device in the annular groove. In addition, it is easy to position the projection in the second groove. Therefore, errors in positioning the sealing device are less likely to occur.

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

[0058] This reciprocating mechanism reduces the risk of confusing the projection with the outer lip. Therefore, it further reduces the likelihood of incorrect placement of the projection relative to the second groove.

[0059] In the sixth embodiment, which is a preferred example of the third embodiment, the position of the tip of the outer peripheral lip is located radially outward from the position of the tip of the at least one projection.

[0060] This reciprocating mechanism makes it possible to increase the contact force of the outer lip with the first member, and also suppresses the risk of the sliding performance of the sealing device with respect to the first member decreasing due to excessive contact of the projection with the first member. [Explanation of symbols]

[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 circumferential surface, 2X...Second member, 21...Outer circumferential surface, 40...Main body, 40X...Main body, 41...Lip, 42...Protrusion, 100...Reciprocating mechanism, 201...First groove, 202...Second groove, 411...Outer circumferential lip, 412...Inner circumferential lip, 421...Tip, 2011...Bottom, 2012...Side, 2013...Side, 2021...Bottom, 2022...Side, 4121...Tip, A0...Arrow, A1...Axis, W1...Depth, W2...Depth, T1...Height, T2...Height.

Claims

1. A first member having an inner circumferential surface, A second member is inserted radially inward from the inner circumferential surface and moves axially relative to the first member, The device comprises a sealing device for sealing the annular gap formed between the first member and the second member, An annular groove is provided on the outer circumferential surface of the second member. The aforementioned annular groove is The annular first groove, It comprises at least one second groove connected to the first groove and having a depth smaller than the depth of the first groove, The aforementioned sealing device is The main body and A lip portion protruding from the main body in the axial direction, The main body comprises at least one projection that protrudes in a second projection direction opposite to the first projection direction in which the lip portion protrudes in the axial direction, The main body portion and the lip portion are arranged in the first groove portion. The at least one projection is positioned in the second groove of the at least one projection. A reciprocating mechanism characterized by the following:

2. The aforementioned at least one projection is a plurality of projections spaced apart from each other, The aforementioned at least second groove portion is a plurality of second groove portions spaced apart from each other, The plurality of protrusions are arranged in a one-to-one ratio with respect to the plurality of second grooves. The reciprocating mechanism according to claim 1.

3. The lip portion comprises an outer circumferential lip and an inner circumferential lip that is spaced apart from the outer circumferential lip and located radially inward from the outer circumferential lip. The at least one projection is located radially outward from the inner circumferential lip, The reciprocating mechanism according to claim 1.

4. The radial position of the connection portion between the at least one projection and the main body overlaps with the radial position of the connection portion between the outer lip and the main body. The reciprocating mechanism according to claim 3.

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

6. The position of the tip of the outer lip is located radially outward from the position of the tip of at least one projection. The reciprocating mechanism according to claim 3.

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