sealing device

Abstract

A sealing device (100) is disposed in a gap (320) between an outer circumferential surface (210) of a rotating shaft (200) and an inner circumferential surface (310) of a shaft hole (301) in a housing (300) having the shaft hole (301) into which the rotating shaft (200) is inserted, and seals the gap (320). The sealing device (100) is provided with a core metal (30) composed of a metal material, and a seal body constituent member (20) which is composed of an elastic body and in which the core metal (30) is integrated. The seal body constituent member (20) is provided with: a seal body (10) including a lip part (23); and a conductive lip (50) and a conductive protective ring (40) which are attached to the seal body (10). The protective ring (40) has an abutting part (41) abutting on the housing (300), and an inward extension part (42) extending radially inward from the abutting part (41). The conductive lip (50) is integrated with the seal body (10) by being held between the inward extension part (42) and the seal body (10).

Description

Technical Field

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

Background Art

[0002] A sealing device disposed in a gap between an outer peripheral surface of a rotating shaft and an inner peripheral surface of a shaft hole in a housing having the shaft hole into which the rotating shaft is inserted is known.

[0003] As shown in FIG. 10, the sealing device (sealing device 1000) can be used, for example, by being incorporated into a speed reducer 1900 of an electric vehicle (EV) or a fuel cell vehicle (FCV). In the example of FIG. 10, the speed reducer 1900 includes a housing 1300, first, second, and third rotating shafts 1201, 1202, and 1203 provided on the housing 1300, and a plurality of bearings 1400 provided on the housing 1300 and bearing the first, second, and third rotating shafts 1201, 1202, and 1203, respectively. Power of the battery 1500 is supplied to the electric motor 1700 via the inverter 1600, and when the electric motor 1700 is driven, the first rotating shaft 1201, which is the output shaft of the electric motor 17, rotates. The first rotating shaft 1201, the second rotating shaft 1202, and the third rotating shaft 1203 are connected in this order via a gear 1220. The rotation of the first rotating shaft 1201 is transmitted from the first rotating shaft 1201 to the second rotating shaft 1202, and further transmitted from the second rotating shaft 1202 to the third rotating shaft 1203. That is, the rotation of the first rotating shaft 1201 is transmitted to the third rotating shaft 1203 at a desired reduction ratio. A wheel 1800 is provided on the third rotating shaft 1203.

[0004] However, in a mechanism equipped with rotating shafts (first rotating shaft 1201, second rotating shaft 1202, and third rotating shaft 1203) driven by an electric motor 1700, as shown in the example in Figure 10, the induced current generated by the electric motor 1700 can cause electromagnetic noise from AM radio to be generated from the rotating shafts, or sparks to occur in the bearing 1400, leading to electrolytic corrosion of the bearing 1400. To solve these problems, it is desirable to ensure power supply between the rotating shaft and the housing 1300, that is, to ground the rotating shaft to the housing 1300. While earth brushes exist as an existing technology for this purpose, they have drawbacks such as requiring a dedicated space and generating brush wear dust.

[0005] One technology that can solve the aforementioned problems is a sealing device equipped with a conductive lip. The sealing device described in Patent Document 1 (the sealing ring in the same document) comprises a sealing body having a lip portion (the sealing lip in the same document) and a conductive lip (the pre-seal in the same document) provided on the atmospheric side of the sealing body. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-142065 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, according to the inventors of the present invention, there is room for improvement in the integration of the conductive lip and the seal body in the technology of Patent Document 1.

[0008] The present invention has been made in view of the above problems, and provides a sealing device with a structure that can achieve good integration between the conductive lip and the seal body. [Means for solving the problem]

[0009] According to the present invention, a sealing device is provided which is placed in the gap between the outer circumferential surface of a rotating shaft and the inner circumferential surface of the shaft hole in a housing having a shaft hole into which the rotating shaft is inserted, and which seals the gap, The seal comprises a core made of a metal material and a seal body component made of an elastic material into which the core is integrated, wherein the seal body component includes a seal body including a lip portion, A conductive lip and a conductive protective ring are attached to the seal body, Equipped with, The protective ring has a contact portion that abuts against the housing and an inward extension portion that extends radially inward from the contact portion. The conductive lip is integrated with the seal body by being sandwiched between the inwardly extending portion and the seal body. Occasionally, The radially inner end of the inward extension is a bent portion that curves toward the conductive lip side. A sealing device is provided. [Effects of the Invention]

[0010] According to the present invention, good integration between the conductive lip and the seal body can be achieved. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows a sealing device according to the first embodiment, and shows a cut end face along the axis of rotation. [Figure 2] This is a magnified section of Figure 1. [Figure 3] This figure shows a sealing device according to a modified example 1 of the first embodiment, and shows a cut end face along the axis of rotation. [Figure 4] This figure shows a sealing device according to a modified example 2 of the first embodiment, and shows a cut end face along the axis of rotation. [Figure 5] This figure shows a sealing device according to a modified example 3 of the first embodiment, and shows a cut end face along the axis of rotation. [Figure 6] It is an exploded perspective view of a sealing device according to Modification Example 3 of the first embodiment. [Figure 7] It is a view showing a sealing device according to Modification Example 4 of the first embodiment, and shows a cut end face along the axis of the rotating shaft. [Figure 8] It is a view showing a sealing device according to Modification Example 5 of the first embodiment, and shows a cut end face along the axis of the rotating shaft. [Figure 9] It is a view showing a sealing device according to the second embodiment, and shows a cut end face along the axis of the rotating shaft. [Figure 10] It is a schematic diagram for explaining the problems of a general sealing device.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description will be omitted as appropriate.

[0013] 〔First Embodiment〕 First, the first embodiment will be described using FIGS. 1 and 2. The sealing device 100 according to the present embodiment is disposed in a gap 320 between an outer peripheral surface 210 of a rotating shaft 200 and an inner peripheral surface 310 of a shaft hole 301 in a housing 300 having the shaft hole 301 into which the rotating shaft 200 is inserted, and seals the gap 320. The sealing device 100 includes a seal body 10, a conductive lip 50 attached to the seal body 10, and a conductive protective ring 40. The seal body 10 includes a core metal 30 made of a metal material and a seal body constituent member 20 made of an elastic body and integrated with the core metal 30. The seal body constituent member 20 includes a lip portion 23. The protective ring 40 has a contact portion 41 that contacts the housing 300 and an inward extending portion 42 that extends radially inward from the contact portion 41. The conductive lip 50 is integrated with the seal body 10 by being sandwiched between the inwardly extending portion 42 and the seal body 10.

[0014] Here, the sealing device 100 is positioned in the gap 320 such that its central axis AX coincides with the axis of rotation 200. In the following explanation, the direction perpendicular to the central axis AX will be referred to as the radial direction. Furthermore, within the radial direction, the direction away from the central axis AX is referred to as the radially outward direction, and the direction approaching the central axis AX is referred to as the radially inward direction. Furthermore, the direction in which a circle revolves around the central axis AX is called the circumferential direction. Furthermore, the direction along the central axis AX is sometimes simply referred to as the axial direction. Furthermore, one side of the direction along the central axis AX (the right side in Figures 1 and 2) is the internal side (machine side) of the mechanism in which the sealing device 100 is installed, and this direction is referred to as the internal side 330. The other side of the direction along the central axis AX (the left side in Figures 1 and 2) is the external side (atmospheric side) of the mechanism in which the sealing device 100 is installed, and this direction is referred to as the external side 340.

[0015] According to the sealing device 100 of this embodiment, when the sealing device 100 is assembled to the housing 300 and the gap 320 between the shaft hole 301 of the housing 300 is sealed, the protective ring 40 and the conductive lip 50 each form a portion of the conductive path between the housing 300 and the rotating shaft 200. This ensures that current flows between the rotating shaft 200 and the housing 300 through the protective ring 40 and the conductive lip 50, that is, the rotating shaft can be grounded to the housing 300. Therefore, it is possible to suppress the generation of electromagnetic noise from AM radios from the rotating shaft and the occurrence of electrolytic corrosion of the bearings. Furthermore, according to the sealing device 100 of this embodiment, the conductive lip 50 is integrated with the seal body 10 by being sandwiched between the inwardly extending portion 42 and the seal body 10, thus achieving good integration between the conductive lip 50 and the seal body 10. Since the sealing device 100 can replace existing sealing devices, a dedicated space for the earth brush is not required, and wear particles from the brush are not generated. Furthermore, unlike technologies that ensure electrical conductivity between the rotating shaft 200 and the housing 300 using only a conductive lip, this technology ensures conductivity using both the conductive lip 50 and the protective ring 40, which is a metal component. This also reduces the electrical resistance of the conductive path from the rotating shaft 200 to the housing 300.

[0016] In the present invention, the lip portion 23 may be an oil lip or a dust lip. In this embodiment, the lip portion 23 is an oil lip. That is, the seal body 10 constitutes an oil seal body. The sealing device 100 combines a seal body 10 having an oil lip portion 23 and a conductive lip 50, thus enabling a balance between oil sealing performance and conductivity while reducing the number of parts and installation space. By positioning the conductive lip 50 on the outer side 340 (atmospheric side) of the contact point between the oil lip portion 23 and the rotating shaft 200, conductivity can be imparted without compromising the oil seal performance. The sealing device 100 prevents foreign matter from entering the interior side 330 from the exterior side 340 by the lip portion 23 and the conductive lip 50, and the lip portion 23 prevents lubricant from leaking from the interior side 330 to the exterior side 340.

[0017] The present embodiment will be described in more detail below.

[0018] One example of a mechanism in which the sealing device 100 is installed is a reduction gear for an electric vehicle (EV) or a fuel cell vehicle (FCV), which comprises a housing 300 made of metal. The housing 300 has a shaft hole 301 into which a rotating shaft 200 is inserted. Normally, of the sealing device 100 and the rotating shaft 200, the sealing device 100 is inserted and fixed into the shaft hole 301 first, and then the rotating shaft 200 is inserted.

[0019] The seal body component 20 is formed in an annular shape with the central axis AX at its center. The seal body component 20 includes, for example, a body contact portion 21 formed in a cylindrical shape concentric with the central axis AX, a body inward extension portion 22 extending radially inward in an inner flange shape from one end of the body contact portion 21 in the axial direction (the end on the outer side 340), and a lip portion 23 extending axially (towards the inner side 330) from the radially inward end of the body inward extension portion 22. The lip portion 23 also has a cylindrical shape that can be described as concentric with the central axis AX. The lip portion 23 is spaced apart from the main body contact portion 21 and positioned inside the main body contact portion 21, and the main body contact portion 21 and the lip portion 23 face each other in the radial direction. The seal body component 20 is formed in a three-dimensional shape that corresponds to the trajectory of movement of the cut end face shape when the cut end face shape of the seal body component 20 shown in Figure 2 is rotated once around the central axis AX. A portion of the outer circumferential surface of the main body contact portion 21 forms a contact surface 21a that is pressed in a circumferential manner against the inner circumferential surface 310 of the shaft hole 301. The lip portion 23 is pressed against the outer circumferential surface 210 of the rotating shaft 200 in a circumferential manner, and slides against the outer circumferential surface 210 when the rotating shaft 200 rotates. The sealing performance is ensured by the pressure contact points between the contact surface 21a and the inner circumferential surface 310, and between the lip portion 23 and the outer circumferential surface 210. Hereinafter, the collectively referred to as the sealing area is the contact point between the contact surface 21a and the inner circumferential surface 310, and the contact point between the lip portion 23 and the outer circumferential surface 210. In this embodiment, the lip portion 23 is an oil lip, and the area 330 inside the sealing portion is filled with a lubricant such as lubricating oil.

[0020] Since conductivity is not required for the lip portion 23, a general sealing rubber material can be used as the material for the seal body component 20. Examples of such elastic materials include synthetic rubbers such as nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), and fluororubber (FKM).

[0021] The seal body component 20 is integrally molded as a single unit. More specifically, the seal body component 20 is integrally molded together with the core metal 30. For example, a core metal 30 (and a garter spring 60, as described later, if necessary) can be placed in a mold (not shown), an uncrosslinked rubber material can be injected, and then the inside of the mold cavity can be heated and pressurized to crosslink the rubber material, thereby obtaining a seal body 10 in which the seal body components 20 and the core metal 30 are integrally molded.

[0022] Examples of metal materials that make up the core 30 include stainless steel (SUS) or cold-rolled steel (SPCC). The core metal 30 can be formed by pressing or forging.

[0023] The core metal 30 includes, for example, a cylindrical portion 31 formed concentrically with the central axis AX, and a core metal inward extension portion 32 that extends radially inward in an inner flange shape from one end of the cylindrical portion 31 in the axial direction (the end of the outer side 340). In this embodiment, the inward extension portion 32 of the core metal is formed in a flat, donut-shaped form perpendicular to the central axis AX. The core metal 30 is formed in a three-dimensional shape that corresponds to the trajectory of movement of the cut end face shape when the cut end face shape of the core metal 30 shown in Figure 2 is rotated once around the central axis AX. In this embodiment, the core metal 30 is entirely embedded in the seal body component 20 and is not exposed from the seal body component 20. The cylindrical portion 31 is arranged, for example, from inside the main body contact portion 21 to inside the boundary between the main body contact portion 21 and the main body inward extension portion 22. The core metal inward extension portion 32 is arranged from inside the boundary between the main body contact portion 21 and the main body inward extension portion 22 to inside the main body inward extension portion 22. For example, the inner periphery of the core metal inward extension portion 32 is located near the boundary between the main body inward extension portion 22 and the lip portion 23.

[0024] As described above, the protective ring 40 has a contact portion 41 and an inwardly extending portion 42. The contact portion 41 is formed, for example, in a cylindrical shape concentric with the central axis AX. The inwardly extending portion 42 extends radially inward in an inner flange shape from one end of the abutment portion 41 in the axial direction (the end of the outer side 340). In this embodiment, the inwardly extending portion 42 is a flat plate-like shape perpendicular to the central axis AX and is formed in a donut shape. The protective ring 40 is formed in a three-dimensional shape that corresponds to the trajectory of movement of the cut end face shape when the cut end face shape of the protective ring 40 shown in Figure 2 is rotated once around the central axis AX. The outer circumferential surface of the contact portion 41 is pressed against the inner circumferential surface 310 of the shaft hole 301 in a circumferential manner. The material of the protective ring 40 is preferably a metallic material, such as stainless steel (SUS) or cold-rolled steel (SPCC). The protective ring 40 can be formed by pressing or forging.

[0025] The conductive lip 50 is formed in a donut shape with the central axis AX at its center. A portion of the conductive lip 50 (the radially outer portion) is positioned along the surface facing the outer side 340 in the inward extension portion 22 of the seal body component 20. In this embodiment, the radially inner portion of the conductive lip 50 extends radially inward beyond the inward extension portion 42. The radially inner portion of the conductive lip 50 protrudes radially inward from the radially inner end of the inward extension portion 22 of the main body. In the conductive lip 50, the portion extending radially inward from the inward extension portion 42 is bent toward the outer side 340 (left side in Figure 2). The conductive lip 50 is formed in a three-dimensional shape that corresponds to the trajectory of movement of the cut end face shape when the cut end face shape of the conductive lip 50 shown in Figure 2 is rotated once around the central axis AX. In this embodiment, the tip of the conductive lip 50 (the radially inner end) contacts the outer circumferential surface 210 of the rotating shaft 200 in a circumferential manner, thereby ensuring electrical conductivity between the rotating shaft 200 and the conductive lip 50. Furthermore, the tip of the conductive lip 50 slides against the outer surface 210 when the rotating shaft 200 rotates.

[0026] In this embodiment, sealing properties are not required for the conductive lip 50. Therefore, a material specifically designed for conductivity can be used for the conductive lip 50, such as conductive rubber or conductive resin. A preferred material for the conductive lip 50 is conductive PTFE (polytetrafluoroethylene).

[0027] The garter spring 60 is composed of a coil spring, the ends of which are connected to each other, and the axis of the coil spring forms an annular loop. The axis of the coil spring makes one full rotation around the central axis AX. In other words, the garter spring 60 is formed in an annular shape along the circumferential direction. The garter spring 60 is a tension-type coil spring and exerts a biasing force that shortens its axial length. Because the garter spring 60 has an annular loop shape, it exerts a biasing force that shortens the radius of the loop. The garter spring 60 is positioned in a groove formed in a circumferential manner on the outer circumferential surface of the lip portion 23 (the surface facing the cylindrical portion 31), and biases the lip portion 23 radially inward. Therefore, the garter spring 60 plays the role of restraining the lip portion 23 with respect to the rotating shaft 200. This ensures that the inner edge of the lip portion 23 is in good contact with the outer surface 210 of the rotating shaft 200.

[0028] Furthermore, in the lip portion 23, the area that is pressed against the outer peripheral surface 210 is spaced apart (spaced apart on the inner side 330) from the boundary between the inward extension portion 22 of the main body and the lip portion 23. The portion of the lip portion 23 closer to the inward extension portion 22 of the main body than the area that is pressed against the outer peripheral surface 210, and the boundary between the lip portion 23 and the inward extension portion 22 of the main body, are not in contact with the outer peripheral surface 210, and a gap is created between these portions and the outer peripheral surface 210.

[0029] In this embodiment, the seal body component 20 sandwiches the conductive lip 50 together with the inwardly extending portion 42 of the protective ring 40. More specifically, of the core metal 30 and the seal body component 20, only the seal body component 20, together with the inwardly extending portion 42, clamps the conductive lip 50 (the radially outer portion of the conductive lip 50), while the core metal 30 does not clamp the conductive lip 50. The inward extension 42 is positioned along the outer surface 340 (left side in Figure 2) of the inward extension 22 of the main body, and the conductive lip 50 is sandwiched between the inward extension 22 of the main body and the inward extension 42.

[0030] In this embodiment, the seal body component 20 has a recess 22a in which a portion of the conductive lip 50 (the radially outer portion of the conductive lip 50) is positioned. Therefore, during and after the assembly of the sealing device 100, the conductive lip 50 can be more stably positioned and fixed to the seal body component 20, and consequently to the seal body 10. In other words, the sealing device 100 has excellent ease of manufacture and structural stability.

[0031] The recess 22a is formed on the outer surface 340 (left side in Figure 2) of the inward extension portion 22 of the main body. The depth of the recess 22a (dimension along the central axis AX) is less than the thickness of the conductive lip 50 before assembly to the seal body 10, and the conductive lip 50 is compressed and sandwiched between the inward extension portion 42 and the bottom surface of the recess 22a. The outer edge of the conductive lip 50 is positioned by the outer edge of the recess 22a. In this way, the conductive lip 50 is fitted onto the seal body component 20.

[0032] Here, in the radial direction, the distance from the inner edge to the outer edge of the conductive lip 50, i.e., {(outer diameter of the conductive lip 50) - (inner diameter of the conductive lip 50)} / 2, is shorter than the distance from the outer surface 210 of the rotating shaft 200 to the inner surface 310 of the housing 300, i.e., {(inner diameter of the shaft hole 301) - (outer diameter of the rotating shaft 200)} / 2. Furthermore, the outer edge of the conductive lip 50 is located radially inward from the contact surface 21a of the seal body component 20. More specifically, the outer edge of the conductive lip 50 is located radially inward from the inner surface (of the contact portion 41) of the protective ring 40. For this reason, a structure in which the conductive lip 50 is fitted into the recess 22a can be easily realized. Because the conductive lip 50 is formed to these dimensions, (unlike the conductive lip in Patent Document 1 (the pre-seal in the same document)) the outer edge of the conductive lip 50 does not reach the inner surface 310 (it is spaced apart from the inner surface 310).

[0033] In this embodiment, the protective ring 40 is fixed to the seal body component 20. More specifically, the contact portion 41 of the protective ring 40 is crimped and fixed to the outer circumferential surface of the outer end 340 of the seal body component 20. In the axial direction, the area in which the contact portion 41 is located generally overlaps with the area in which the inward extension portion 22 of the seal body component 20 is located, and the contact portion 41 is crimped and fixed to the outer circumferential surface of the boundary between the body contact portion 21 and the body inward extension portion 22.

[0034] The sealing device 100 is configured as described above.

[0035] The assembly of the conductive lip 50 and protective ring 40 to the seal body 10 can be performed, for example, by first aligning the conductive lip 50 with the seal body 10, and then fitting the protective ring 40 onto the seal body 10. That is, after positioning a portion of the conductive lip 50 (the radially outer portion) in the recess 22a of the inwardly extending portion 22 of the body, the contact portion 41 of the protective ring 40 can be fitted onto the seal body component 20, thereby assembling the conductive lip 50 and protective ring 40 to the seal body 10.

[0036] In this case, before the conductive lip 50 is assembled to the seal body 10, the conductive lip 50 may be flat as a whole, or it may be bent as shown in Figure 2 from the state before it is assembled to the seal body 10. If the conductive lip 50 is flat (donut-shaped) before being assembled to the seal body 10, when the conductive lip 50 is assembled to the seal body 10, the radially outer portion of the conductive lip 50 is sandwiched and compressed by the inward extension portion 42 and the main body inward extension portion 22, causing strain to occur in the conductive lip 50. As a result, the portion of the conductive lip 50 that extends radially inward from the inward extension portion 42 bends toward the inward extension portion 42 (left side in Figure 2). This is because the inner circumference of the inward extension portion 42 is located radially outward from the inner circumference of the portion of the main body inward extension portion 22 that is positioned along the conductive lip 50.

[0037] The sealing device 100 is fixed to the housing 300. Specifically, the sealing device 100 is fixed to the housing 300 by being inserted into the shaft hole 301 such that the contact surface 21a and the contact portion 41 are pressed against and fixed to the inner circumferential surface 310.

[0038] In this case, before the rotating shaft 200 is inserted into the sealing device 100, it is preferable that the inner diameter of the conductive lip 50 is smaller than the inner diameter of the lip portion 23. By doing so, a structure can be realized in which, after the rotating shaft 200 has been inserted into the sealing device 100, the contact area between the rotating shaft 200 and the conductive lip 50 is larger than the contact area between the rotating shaft 200 and the lip portion 23. In other words, a structure can be realized in which the distance L2 is longer than the distance L1 shown in Figure 2. This makes it possible to more reliably ensure conductivity by the conductive lip 50. Furthermore, the lip portion 23 has higher rigidity than the conductive lip 50, and even if the contact area between the rotating shaft 200 and the lip portion 23 is smaller than the contact area between the rotating shaft 200 and the conductive lip 50, sufficient sealing performance can be ensured by the lip portion 23.

[0039] <Modification 1 of the first embodiment> Next, a modified example 1 of the first embodiment will be described using Figure 3. The sealing device 100 according to this modified example differs from the sealing device 100 according to the first embodiment described above in the respects described below, and is otherwise configured in the same way as the sealing device 100 according to the first embodiment described above.

[0040] In this modified example, the radially inner end (edge) of the inward extension 42 of the protective ring 40 is a bent portion 42b that is bent toward the conductive lip 50 side. As a result, the bent portion 42b presses against the conductive lip 50, so that the tip of the conductive lip 50 can always maintain contact with the outer surface 210 of the rotating shaft 200. Therefore, it is possible to suppress the decrease in the adhesion of the conductive lip 50 to the rotating shaft 200 due to the deterioration of the conductive lip 50 over time, and the electrical conductivity between the rotating shaft 200 and the housing 300 can be maintained.

[0041] More specifically, the bent portion 42b is bent toward one side (the inner side 330: the right side in Figure 3) relative to the portion of the inward extension 42 other than the bent portion 42b. In other words, the bent portion 42b is bent in the opposite direction to the bending direction of the conductive lip 50 (the left side in Figure 3), and presses the conductive lip 50 in that direction. As a result, the bent portion 42b can press the conductive lip 50 against the rotating shaft 200, and even if the conductive lip 50 deteriorates over time, it is possible to prevent the conductive lip 50 from deforming in a direction away from the rotating shaft 200 (radially outward).

[0042] <Modification 2 of the first embodiment> Next, a modified example 2 of the first embodiment will be described using Figure 4. The sealing device 100 according to this modified example differs from the sealing device 100 according to the first embodiment described above in the respects described below, and is otherwise configured in the same way as the sealing device 100 according to the first embodiment described above.

[0043] In this modified example, the core metal 30, together with the inwardly extending portion 42 of the protective ring 40, sandwiches the conductive lip 50. Since the core metal 30 is a metal component with higher rigidity than the seal body component 20, the conductive lip 50 can be more stably clamped between the inwardly extending portion 42 and the seal body 10.

[0044] More specifically, the radially outer portion of the conductive lip 50, in particular the radially outer portion, is held between the inward extension portion 42 and the core metal 30, while the radially inner portion of the radially outer portion of the conductive lip 50, in particular, is held between the inward extension portion 42 and the seal body component 20. However, the present invention is not limited to this example, and in the seal body 10, the portion that clamps the radially outer portion of the conductive lip 50 together with the inwardly extending portion 42 may consist only of the core metal 30.

[0045] The core metal inward extension portion 32 is formed in a flat plate shape perpendicular to the central axis AX, except for, for example, the radially inner end (edge) (the bent portion 32b described below), and the radially inner end is a bent portion 32b that is bent in a crank shape toward the inner side 330 (right side in Figure 4). In the core metal inward extension portion 32, the portion formed in a flat plate shape perpendicular to the central axis AX and the boundary portion between the core metal inward extension portion 32 and the cylindrical portion 31 are exposed to the outer surface (outer side 340 surface) of the seal body 10. Furthermore, in the inward extension portion 32 of the core metal 30, a portion of the surface facing the outer side 340 (left side in Figure 4) forms a contact surface 32a that makes surface contact with the conductive lip 50.

[0046] In this modified example, the protective ring 40 is fixed to the core metal 30. In other words, since the protective ring 40 is fixed to the core metal 30, which is a metal component, the retention of the protective ring 40 with respect to the seal body 10 can be improved.

[0047] More specifically, a portion of the outer circumferential surface of the core metal 30, from the cylindrical portion 31 to the boundary between the cylindrical portion 31 and the inwardly extending portion 32 of the core metal, is exposed to the outer circumferential surface of the seal body 10, and this exposed portion has a contact surface 31a that makes surface contact with the inner circumferential surface of the contact portion 41 of the protective ring 40. The contact portion 41 is directly crimped and fixed to the contact surface 31a. More specifically, the contact surface 31a is exposed in the portion of the outer circumferential surface of the seal body 10 that includes the end of the outer side 340. The portion of the cylindrical portion 31 on the side of the core metal inward extension portion 32 (i.e., the outer side 340) and the boundary portion between the cylindrical portion 31 and the core metal inward extension portion 32 are radially outward bulging (thicker) than the inner side 330 portion of the cylindrical portion 31, and this bulging portion has a contact surface 31a.

[0048] In this modified example, the conductive path from the rotating shaft 200 to the housing 300 includes a path via the conductive lip 50 and protective ring 40, as well as a path via the conductive lip 50, core metal 30, and protective ring 40. This also reduces the electrical resistance of the conductive path from the rotating shaft 200 to the housing 300.

[0049] In this case, the seal body component 20 does not have a recess 22a.

[0050] <Modification 3 of the first embodiment> Next, a third modified example of the first embodiment will be described using Figures 5 and 6. The sealing device 100 according to this modified example differs from the sealing device 100 according to the first embodiment described above in the respects described below, and is otherwise configured in the same way as the sealing device 100 according to the first embodiment described above.

[0051] In this modified example, the sealing device 100 further includes a disc spring 70 interposed between the inward extension 42 of the protective ring 40 and the conductive lip 50, the disc spring 70 pressing the portion of the conductive lip 50 that extends radially inward from the inward extension 42 toward the opposite side from the inward extension 42 (i.e., the inner side 330). This allows the tip of the conductive lip 50 to maintain contact with the outer surface 210 of the rotating shaft 200. Therefore, it is possible to suppress the decrease in the adhesion of the conductive lip 50 to the rotating shaft 200 due to the deterioration of the conductive lip 50 over time, and to maintain electrical conductivity between the rotating shaft 200 and the housing 300.

[0052] The shape of the disc spring 70 is not particularly limited, but as an example, the disc spring 70 has a flat, donut-shaped main body portion 71 perpendicular to the central axis AX, and a plurality of wing portions 72 projecting radially inward from the inner circumferential edge of the main body portion 71. The wing portions 72 are arranged in a line along the circumferential direction of the main body portion 71 (for example, at equal intervals). The wing portions 72 have a plurality of radially extending slits 73 formed therein. The wing portions 72 are bent toward the outer side 340 with respect to the main body portion 71. However, the disc spring 70 may have an inner circumferential portion (not shown) that is formed in a shape corresponding to the outer circumferential surface of a truncated cone (truncated cone) centered on the central axis AX, instead of the multiple wing portions 72. The disc spring 70 is preferably made of a metal material.

[0053] In this modified example, as shown in Figure 6, the conductive lip 50 is flat as a whole before it is compressed by being held between the inward extension portion 42, the disc spring 70, and the inward extension portion 22 of the main body. However, as shown in Figure 5, the conductive lip 50 bends when it is compressed by being held between the inward extension portion 42, the disc spring 70, and the inward extension portion 22 of the main body. However, the present invention is not limited to this example, and the conductive lip 50 may be bent as shown in Figure 5 even before it is compressed by being held between the inward extension portion 42, the disc spring 70, and the inward extension portion 22 of the main body.

[0054] <Modification 4 of the First Embodiment> Next, a modified example 4 of the first embodiment will be described using Figure 7. The sealing device 100 according to this modified example differs from the sealing device 100 according to the first embodiment described above in the respects described below, and is otherwise configured in the same way as the sealing device 100 according to the first embodiment described above.

[0055] In this modified example, the conductive lip 50 has a base portion 50a extending radially inward from the inward extension portion 42 and a tip portion 50b that is folded back radially outward from the radially inward end of the base portion 50a. The sealing device 100 further includes a garter spring 80 positioned at the boundary between the base portion 50a and the tip portion 50b, which restrains the portion of the conductive lip 50 extending radially inward from the inward extension portion 42 with respect to the rotating shaft 200. The garter spring 80 is similar to the garter spring 60 and is formed in an annular loop shape along the circumferential direction. The garter spring 80 is arranged circumferentially on the radially outward-facing surface at the boundary between the base 50a and the tip 50b of the conductive lip 50. As a result, the garter spring 80 presses the conductive lip 50 radially inward. Therefore, according to this modified example, the adhesion of the conductive lip 50 to the rotating shaft 200 can be improved. In this modified example, the portion of the conductive lip 50 that circumferentially contacts and slides against the outer circumferential surface 210 of the rotating shaft 200 is the portion facing radially inward at the boundary between the base portion 50a and the tip portion 50b.

[0056] Preferably, the portion of the conductive lip 50 that extends radially inward from the inward extension portion 42 is formed to be thicker than the radially outward portion of the conductive lip 50. By doing so, it is possible to suppress excessive deformation of the conductive lip 50 due to the biasing force of the garter spring 80.

[0057] <Modification 5 of the First Embodiment> Next, a modified example 5 of the first embodiment will be described using Figure 8. The sealing device 100 according to this modified example differs from the sealing device 100 according to the first embodiment described above in the respects described below, and is otherwise configured in the same way as the sealing device 100 according to the first embodiment described above.

[0058] In this modified example, the portion of the seal body 10 that is positioned along the conductive lip 50 has a backup portion 22b that protrudes locally radially inward. As a result, when assembling the mechanism including the sealing device 100, even if the portion of the conductive lip 50 that extends radially inward beyond the inward extension portion 42 is pressed against the inner side 330 by friction with the rotating shaft 200, the conductive lip 50 is supported by the backup portion 22b, thus preventing the conductive lip 50 from bending and turning towards the inner side 330. More specifically, the portion of the seal body 10 that is positioned along the conductive lip 50 (and the backup portion 22b) is a part of the seal body component 20.

[0059] [Second Embodiment] Next, a second embodiment will be described using Figure 9. The sealing device 100 according to this embodiment differs from the sealing device 100 according to the first embodiment described above in the respects described below, and is otherwise configured in the same way as the sealing device 100 according to the first embodiment.

[0060] In this embodiment, the lip portion 23 of the seal body 10 is a dust lip. The sealing device 100 combines a seal body 10 having a lip portion 23 which is a dust lip, and a conductive lip 50, thus enabling a balance between dust sealing performance and conductivity while reducing the number of parts and installation space. By positioning the conductive lip 50 inward 330 from the contact point between the lip portion 23, which is a dust lip, and the rotating shaft 200, conductivity can be provided without impairing the dust sealing performance. In particular, it can ensure electrical conductivity with a small number of parts, even in wet environments where earth brushes were difficult to apply. The sealing device 100 prevents foreign matter from entering the interior side 330 from the exterior side 340 by means of the lip portion 23 and the conductive lip 50. In this embodiment, a separate oil seal (having an oil lip) may be placed inside the conductive lip 50 at 330.

[0061] In the first embodiment, the portion of the seal body component 20 arranged along the inner circumferential surface 310 was described as including a body contact portion 21 and a boundary portion between the body contact portion 21 and the body inward extension portion 22. In contrast, in this embodiment, the entire portion of the seal body component 20 that is arranged along the inner circumferential surface 310 is considered to be the body contact portion 21. Therefore, in this embodiment as well, the body contact portion 21 of the seal body component 20 is similar to that of the first embodiment in that it has a cylindrical shape. Furthermore, a portion of the main body contact portion 21 (the portion on the inner side 330) extends in an overhang shape from the radially outer end of the inwardly extending portion 22 of the main body toward the inner side 330 (the right side in Figure 9). In this embodiment, the lip portion 23 extends diagonally from the radially inward end of the inwardly extending portion 22 of the main body, radially inward and toward the outer side 340 (left side in Figure 9).

[0062] The seal body component 20 further includes an outward extension portion 25 that extends toward the outer side 340 from the outer side 340 surface of the inward extension portion 22 of the body. The outward extension portion 25 is positioned radially outward from the lip portion 23. In this embodiment, the slinger 90 is fixed to the rotating shaft 200. The slinger 90 rotates in conjunction with the rotation of the rotating shaft 200. The slinger 90 is formed in a stepped flange shape, for example, that shifts in stages toward the interior side 330 toward the radially outward side. The outwardly extending portion 25 extends into the gap between the slinger 90 and the outer circumferential surface 210 of the rotating shaft 200.

[0063] The recess 22a is formed on the surface of the inwardly extending portion 22 of the main body that faces the interior side 330. The conductive lip 50 is positioned in the recess 22a, similar to the first embodiment, and assembled to the seal body component 20. However, the direction in which the conductive lip 50 is bent is the inner side 330 (right side in Figure 9).

[0064] The cylindrical portion 31 of the core metal 30 is embedded in the main body contact portion 21. However, a portion of the cylindrical portion 31 may be exposed from the main body contact portion 21 (from the seal main body component 20). The core metal inward extension portion 32 is embedded from the inside of the boundary between the main body contact portion 21 and the main body inward extension portion 22 into the inside of the main body inward extension portion 22. The core metal inward extension portion 32 may be formed in a flat flange shape, or it may be partially bent to conform to the shape of the seal body component 20.

[0065] The contact portion 41 of the protective ring 40 is formed in a cylindrical shape with an extremely short axial dimension, and is crimped and fixed to the tip of the part that extends in a canopy shape as described above on the main body contact portion 21 (the tip of the inner side 330).

[0066] The inwardly extending portion 42 of the protective ring 40 comprises an outer flange portion 421, an intermediate cylindrical portion 422, and an inner flange portion 423. The outer flange portion 421 extends radially inward in an inner flange shape from the end of the inner side 330 of the contact portion 41. The outer flange portion 421 is positioned along the tip surface (end surface of the inner side 330) of the portion that extends in a canopy shape as described above in the main body contact portion 21. The intermediate cylindrical portion 422 is formed in a cylindrical shape coaxial with the central axis AX. The intermediate cylindrical portion 422 extends from the radially inner end of the outer flange portion 421 toward the outer side 340. The intermediate cylindrical portion 422 is positioned along the inner circumferential surface of the portion of the main body contact portion 21 that extends in a canopy shape as described above. The inner flange portion 423 extends radially inward in an inner flange shape from the outer side 340 end of the intermediate cylindrical portion 422. The inner flange portion 423 is positioned along the surface facing the inner side 330 in the inward extension portion 22 of the main body. In this embodiment, the portion of the protective ring 40 that sandwiches the conductive lip 50 together with the inward extension portion 22 of the main body is the inner flange portion 423.

[0067] Although embodiments and variations have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted. For example, although the above description illustrates an example where the conductive lip 50 is bent, the conductive lip 50 may not be bent, and its entirety may be arranged on the same plane. Furthermore, although the above description explains an example in which the contact portion 41 of the protective ring 40 is selectively crimped and fixed to either the seal body component 20 or the core metal 30, the contact portion 41 may be crimped and fixed across both the seal body component 20 and the core metal 30. Furthermore, the above embodiments and modifications can be combined in any way without departing from the spirit of the present invention.

[0068] This embodiment encompasses the following technical concepts. (1) A sealing device that is placed in the gap between the outer surface of a rotating shaft and the inner surface of the shaft hole in a housing having a shaft hole into which the rotating shaft is inserted, and which seals the gap, The seal comprises a core made of a metal material and a seal body component made of an elastic material into which the core is integrated, wherein the seal body component includes a seal body including a lip portion, A conductive lip and a conductive protective ring are attached to the seal body, Equipped with, The protective ring has a contact portion that abuts against the housing and an inward extension portion that extends radially inward from the contact portion. The conductive lip is integrated with the seal body by being sandwiched between the inwardly extending portion and the seal body in this sealing device. (2) The sealing device according to (1), wherein the seal body component holds the conductive lip together with the inward extension. (3) The sealing device according to (2), wherein the seal body component has a recess in which a portion of the conductive lip is arranged. (4) The sealing device according to any one of (1) to (3), wherein the core metal clamps the conductive lip together with the inward extension. (5) The sealing device according to any one of (1) to (4), wherein the protective ring is fixed to the seal body component. (6) The sealing device according to any one of (1) to (5), wherein the protective ring is fixed to the core metal. (7) The sealing device according to any one of (1) to (6), wherein the radially inner end of the inwardly extending portion is a bent portion that is bent toward the conductive lip side. (8) Further comprising a disc spring interposed between the inwardly extending portion and the conductive lip, The sealing device according to any one of (1) to (6), wherein the disc spring presses the portion of the conductive lip that extends radially inward from the inward extension toward the opposite side from the inward extension. (9) The sealing device according to any one of (1) to (8), wherein the portion of the seal body arranged along the conductive lip has a backup portion that locally protrudes radially inward. (10) The sealing device according to any one of (1) to (9), wherein the lip portion is an oil lip. (11) The sealing device according to any one of (1) to (9), wherein the lip portion is a dust lip.

[0069] This application claims priority based on Japanese Patent Application No. 2023-37276, filed on 10 March 2023, and incorporates all of its disclosures herein. [Explanation of Symbols]

[0070] 10 Sticker body 20 Seal body components 21 Main body contact part 21a Contact surface 22 Inner extension portion of the main body 22a Recess 22b Backup section 23 Lip section 25 Outward extension 30 Mandrel 31 Cylindrical part 31a Contact surface 32 Inward extension of core metal 32a Contact surface 32b Bend part 40 Protective ring 41 Contact part 42 Inward extension 42b Bent part 50 conductive lip 50a base 50b Tip 60 Garter Spring 70 disc springs 71 Main body 72. Blade section 73 Slits 80 Garter Spring 90 Slinger 100 Sealing device 200 rotation axis 210 Outer surface 300 Housing 301 Shaft hole 310 Inner surface 320 Gap 330 Inside 340 External side 421 Outer flange section 422 Intermediate cylindrical section 423 Inner flange section 1000 Sealing device 1201 First rotation axis 1202 Second rotation axis 1203 Third rotation axis 1220 Gear 1300 Housing 1400 bearings 1500 Battery 1600 Inverter 1700 Electric Motor 1800 wheels 1900 speed reducer

Claims

1. A sealing device that is placed in the gap between the outer circumferential surface of a rotating shaft and the inner circumferential surface of the shaft hole in a housing having a shaft hole into which the rotating shaft is inserted, and which seals the gap, The seal comprises a core made of a metal material and a seal body component made of an elastic material into which the core is integrated, wherein the seal body component includes a seal body including a lip portion, A conductive lip and a conductive protective ring are attached to the seal body, Equipped with, The protective ring has a contact portion that abuts against the housing and an inward extension portion that extends radially inward from the contact portion. The conductive lip is integrated with the seal body by being sandwiched between the inwardly extending portion and the seal body. The sealing device has a bent portion at the radially inner end of the inwardly extending portion, which is bent toward the conductive lip side.

2. The sealing device according to claim 1, wherein the seal body component holds the conductive lip together with the inwardly extending portion.

3. The sealing device according to claim 2, wherein the seal body component has a recess in which a portion of the conductive lip is disposed.

4. The sealing device according to claim 1, wherein the core metal, together with the inwardly extending portion, sandwiches the conductive lip.

5. The sealing device according to any one of claims 1 to 4, wherein the protective ring is fixed to the seal body component.

6. The sealing device according to any one of claims 1 to 4, wherein the protective ring is fixed to the core metal.

7. The sealing device according to any one of claims 1 to 4, wherein the portion of the seal body arranged along the conductive lip has a backup portion that protrudes locally radially inward.

8. The sealing device according to any one of claims 1 to 4, wherein the lip portion is an oil lip.

9. The sealing device according to any one of claims 1 to 4, wherein the lip portion is a dust lip.

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