sealing device

Abstract

This sealing device is disposed between two members that contain an object to be sealed and are relatively displaced, such as an electric-vehicle drive shaft and a housing therefor. A sealing body of conductive rubber provided to the sealing device is fixed in a state of contact with the housing by an outer peripheral seal, and seals the object to be sealed by bringing a sealing surface provided on a conducting lip into surface contact with the drive shaft. The sealing surface is provided with a grease groove, in which grease having conductivity is retained. The grease fills a space between the drive shaft and the sealing surface, and forms a conducting circuit along with the sealing body which causes the drive shaft acting as an antenna for electromagnetic noise to have electrical continuity with the housing.

Description

[Technical Field]

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

[0002] In electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles (HVs), and fuel cell vehicles (FCVs), electromagnetic noise is generated by the on / off operation of the inverter that controls the current supplied to the electric motor, or by the induced voltage of the electric motor itself. Electromagnetic noise is transmitted to, for example, the axle, and is radiated from the axle as an antenna. Electromagnetic noise radiated in this way can cause communication problems in on-board radios and wireless devices, and can cause various electronic devices to malfunction, so measures to remove the noise are necessary.

[0003] Japanese Patent Publication No. 2015-207534 (hereinafter referred to as "Patent Document 1") discloses an example of a countermeasure against electromagnetic noise in which various seals (oil seal 23, first dust seal 25, second dust seal 29) are housed inside a case 11 that covers an axle (output shaft 10B, drive shaft 31), and a conductive brush 27 is arranged in contact with the drive shaft 31 (see paragraph

[0021] and FIG. 3 of Patent Document 1). The conductive brush 27 conducts leakage current from the electric motor 2B that drives the output shaft 10B to the case 11 (see paragraphs

[0026] and

[0027] of Patent Document 1).

[0004] Japanese Patent Publication No. 2000-244180 (hereinafter referred to as "Patent Document 2") discloses an example of a countermeasure against electromagnetic noise in which an oil seal 86 made of conductive rubber that seals the rotating shaft 18 of the electric motor 10 is built into the electric motor housing 14, and electromagnetic noise induced in the rotating shaft 18 is released into the electric motor housing 14 (see paragraph

[0027] and Figure 4 of Patent Document 2).

[0005] Japanese Patent Publication No. 2019-151268 (hereinafter referred to as "Patent Document 3") discloses an example of a countermeasure against electromagnetic noise in which a pair of oil seals (inner oil seal 71, outer oil seal 72) is disposed between left and right axles 3A and 3B and a case 4, and a conductive part 70 having conductivity is provided between the pair of oil seals, and electromagnetic noise transmitted to the axles is channeled to the case 4 by the conductive part 70 (see paragraphs

[0028] -

[0032] and Figures 2-3 of Patent Document 3). The conductive part 70 is described as including "...conductive grease 73, and a pair of outer peripheral conductive member 74 and inner peripheral conductive member 75 provided in the conductive grease 73" (see paragraph

[0029] of Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2015-207534 [Patent Document 2] Japanese Patent Publication No. 2000-244180 [Patent Document 3] Japanese Patent Publication No. 2019-151268 Summary of the Invention [Problem to be solved by the invention]

[0007] In the configuration example disclosed in Patent Document 1, the conductive brush requires space, which leads to an increase in the size of the device. In addition, the cost of the conductive brush itself and the space it occupies increases.

[0008] According to the configuration example disclosed in Patent Document 2, the oil seal acts as a conductor to release electromagnetic noise, eliminating the need for dedicated space for components to counter electromagnetic noise, and also reducing the associated increase in component costs. On the other hand, for example, when the dust seals described in Patent Document 1 (first dust seal 25 and second dust seal 29 in Patent Document 1) are used in a location that is not in direct contact with the fluid to be prevented from leaking, the oil seal is prone to damage due to sliding friction with the rotating shaft, shortening its lifespan. This is also true for the configuration example described in Patent Document 1.

[0009] In the configuration example disclosed in Patent Document 3, grease is filled into the space between a pair of oil seals, and as a result, it is possible to reduce sliding friction between the axle and the lips (main lips 92b, 95a) that face the grease. Ta In order to do this, a pair of oil seals is required, which places significant constraints on the layout. Furthermore, similar to the configuration example described in Patent Document 1, a dedicated space is required for the pair of oil seals and the grease storage space.

[0010] As explained above, improvements are desired for all of the configuration examples described in Patent Documents 1 to 3, which are given as examples of measures against electromagnetic noise.

[0011] An object of the present disclosure is to provide an elegant sealing device that can reduce electromagnetic noise originating from an electric motor. [Means for solving the problem]

[0012] One aspect of the sealing device comprises: a seal body made of conductive rubber that is fixed in contact with one of two relatively displaceable members that house an object to be sealed, and that has an integral annular conductive lip that seals the object by contacting a tip of the other of the two members; a seal surface that is provided at the tip of the conductive lip and that comes into surface contact with the other member; conductive grease that is filled between the seal surface and the other member; and a grease groove that is provided on the seal surface and that holds the grease. The seal body has an annular seal lip that contacts and seals with the other one of the members and is integral with the seal body on the inboard side of the conducting lip, and is provided with a fluid return section that returns fluid that has leaked from the inboard side to the atmosphere side surface of the seal lip to the inboard side by a screw pump action, and the conducting lip has a communication groove that communicates a space on the seal lip side with a space on the atmosphere side. .

[0013] Another aspect of the sealing device comprises a seal body made of conductive rubber that is fixed in contact with one of two relatively displaceable members that house an object to be sealed, and that has an integral annular conductive lip that seals the object by contacting a tip of the other of the two members; a seal surface that is provided at the tip of the conductive lip and that comes into surface contact with the other member; and a grease groove that is provided on the seal surface and that holds conductive grease in advance so that the grease can be filled between the seal surface and the other member. The seal body has an annular seal lip that contacts and seals with the other one of the members and is integral with the seal body on the inboard side of the conducting lip, and is provided with a fluid return section that returns fluid that has leaked from the inboard side to the atmosphere side surface of the seal lip to the inboard side by a screw pump action, and the conducting lip has a communication groove that communicates a space on the seal lip side with a space on the atmosphere side. .

[0014] Yet another aspect of the sealing device comprises: a seal body made of conductive rubber, the seal body being fixed in contact with one of two relatively displaceable members that house an object to be sealed, the seal body having an integral annular conductive lip that seals the object by contacting a tip of the other of the two members; a seal surface that is provided at the tip of the conductive lip and that comes into surface contact with the other member; and a grease supply unit that holds conductive grease in a grease groove provided on the seal surface and is configured to fill the gap between the seal surface and the other member with the grease. The seal body has an annular seal lip that contacts and seals with the other one of the members and is integral with the seal body on the inboard side of the conducting lip, and is provided with a fluid return section that returns fluid that has leaked from the inboard side to the atmosphere side surface of the seal lip to the inboard side by a screw pump action, and the conducting lip has a communication groove that communicates a space on the seal lip side with a space on the atmosphere side. . [Effects of the Invention]

[0015] Sophisticated sealing systems can reduce electromagnetic noise generated by the electric motor. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view of a sealing device according to a first embodiment disposed between two members. [Figure 2] FIG. 2 is a perspective view of a sealing device partially shown in cross section; [Figure 3] FIG. 4 is an enlarged front view of a sealing surface provided on the conductive lip. [Figure 4] (A) is a cross-sectional view taken along line AA in FIG. 3, and (B) is a cross-sectional view taken along line BB in FIG. [Figure 5] FIG. 10 is a side view of the seal lip showing another form (threaded projection) of the fluid return portion. [Figure 6] FIG. 6 is a cross-sectional view of a sealing device according to a second embodiment disposed between two members. [Figure 7] FIG. 2 is a perspective view of a sealing device partially shown in cross section; [Figure 8] FIG. 10 is a perspective view of a sealing device according to a third embodiment, partially shown in cross section. DETAILED DESCRIPTION OF THE INVENTION

[0017] The embodiments will be explained with reference to the drawings. Three embodiments, first to third, will be introduced along the following items. [First embodiment] 1. Configuration (1) Two components in which a sealing device is used (2) Overview of the sealing device (3) Reinforcement ring (4) Seal body (5) Conductive lip (a) Overall structure (b) Sealing surface (c) Grease supply section (6) Seal lip (7) Continuity circuit 2. Action and Effects (1) Electromagnetic noise countermeasures (2) Lubrication function (3) Negative pressure prevention function 3. Another embodiment of the fluid return section [Second embodiment] 1. Configuration 2. Action and Effects [Third embodiment] 1. Configuration 2. Action and Effects

[0018] [First embodiment] The first embodiment will be described with reference to FIGS. 1 to 4(A) and 4(B).

[0019] 1. Configuration (1) Two components in which a sealing device is used The sealing device 101 of this embodiment is used in electric vehicles (EVs) such as battery electric vehicles (BEVs), hybrid vehicles (HVs), and fuel cell vehicles (FCVs), and is interposed in a gap 13 between two relatively displaceable members, for example, a drive shaft 11 that rotates using an electric motor (not shown) as a drive source, and its housing 12, to seal a sealed object such as lubricating oil contained in the housing 12 and prevent its leakage. Therefore, the sealing device 101 constitutes a sealing structure that seals a sealed object contained in the housing 12. In FIG. 1, the dashed dotted line indicates an axis A that passes through the center of the drive shaft 11, and the drive shaft 11 rotates around the axis A.

[0020] The housing 12, which is one of the two members, has a shaft hole 14, which connects the inside side I with the atmosphere side O. The drive shaft 11, which is the other of the two members, passes through the shaft hole 14 and is exposed from the inside side I to the atmosphere side O.

[0021] (2) Overview of the sealing device 1, the sealing device 101 has an annular shape (the overall shape is not shown) and is fixedly attached in a shaft hole 14 provided in the housing 12. The axis of the sealing device 101 is common with the axis A of the drive shaft 11.

[0022] The main body of the sealing device 101 is a seal body 121 reinforced by a metal reinforcing ring 111. The seal body 121 is molded from conductive rubber that is bonded to the reinforcing ring 111 by cross-linking and molded integrally, and is provided with an outer circumferential seal 122 on its outer circumferential side that contacts the inner circumferential surface of the shaft hole 14, and a seal portion 123 on its inner circumferential side that contacts the drive shaft 11. The seal portion 123 has a conductive lip 131 and a seal lip 141.

[0023] An object to be sealed, for example, a fluid such as lubricating oil (not shown), is accommodated on the inside side I of the housing 12. The sealing device 101 is disposed in the gap 13 between the drive shaft 11 and the housing 12, thereby sealing the fluid accommodated on the inside side I and preventing leakage to the atmosphere side O.

[0024] (3) Reinforcement ring The reinforcing ring 111 is an annular metal member having a fixed piece 111a that runs parallel to the inner circumferential surface of the shaft hole 14, a bent piece 111b that bends at a right angle from the fixed piece 111a and then folds back diagonally, and a support piece 111c that bends further from the bent piece 111b and faces the drive shaft 11. The fixed piece 111a, bent piece 111b, and support piece 111c are formed, for example, by pressing an annular metal plate.

[0025] The outer circumferential surface of the fixed piece 111a has a smaller diameter than the inner circumferential surface of the shaft hole 14, and the inner circumferential surface of the support piece 111c has a larger diameter than the outer circumferential surface of the drive shaft 11.

[0026] (4) Seal body The seal body 121 is an annular member that entirely covers the reinforcing ring 111 along its shape, and has an outer circumferential seal 122 molded in the portion that covers the outer circumferential side of the fixing piece 111a. The outer circumferential seal 122 has a diameter slightly larger than the inner circumferential surface of the shaft hole 14, and flexes when the sealing device 101 is attached to the shaft hole 14, enabling the sealing device 101 to be fixedly attached inside the shaft hole 14.

[0027] The seal body 121 covers the front and back surfaces of the fixed piece 111a, the bent piece 111b, and the support piece 111c of the reinforcing ring 111, and branches into two at the tip of the support piece 111c. Each of the bifurcated portions extends parallel to the axis A of the drive shaft 11 and forms a seal portion 123. A conductive lip 131 is provided at the end of the portion of the seal portion 123 that extends toward the atmosphere side O, and a seal lip 141 is provided at the end of the portion that extends toward the aircraft interior side I.

[0028] 1 and 2, the conductive lip 131 and the seal lip 141 are disposed so as to contact the drive shaft 11, and close the gap 13 between the drive shaft 11 and the shaft hole 14. At this time, a garter spring 132 is provided on the back side of the conductive lip 131, and a garter spring 142 is provided on the back side of the seal lip 141 so as to surround the seal portion 123. These garter springs 132, 142 increase the tension of the conductive lip 131 and the seal lip 141 against the drive shaft 11.

[0029] (5) Conductive lip (a) Overall structure 2, the conductive lip 131 has an annular sealing surface 133 at its tip 131a. The sealing surface 133 seals the outer circumferential surface of the drive shaft 11 by surface contact. Because of this structure, the conductive lip 131 is not a tongue-type seal that bends when pressed against the object to be sealed and uses a predetermined area extending from the tip toward the base as a sealing surface, but rather a seal that presses the tip 131a against the object to be sealed (drive shaft 11) from a direction perpendicular to the object to be sealed.

[0030] One example of the seal surface 133 is a flat surface, and another example is a curved surface that expands the contact area with the drive shaft 11 by deforming along the outer circumferential surface of the drive shaft 11. Regardless of the shape, the seal surface 133 has an axial length sufficient to allow surface contact with the outer circumferential surface of the drive shaft 11. The axial length of the seal surface 133 will be described later.

[0031] 2 to 4(A) and 4(B), a plurality of grease grooves 134 are provided in the circumferential direction of the seal surface 133. As an example, the number of grease grooves 134 is three. However, the number is not limited to three, and one, two, or four or more grease grooves 134 may be provided in the seal surface 133.

[0032] Grease groove 134 provided on sealing surface 133 of conductive lip 131 stores and holds grease G. Grease G held in grease groove 134 is conductive grease. Due to its structure for holding grease G, grease groove 134 desirably has a certain depth. The cross-sectional shape of grease groove 134 may be any shape that can hold grease G, such as a parabolic shape as shown in Figures 4(A) and (B), a rectangular shape, a curved shape, or the like.

[0033] A plurality of communication grooves 135 are also provided on the seal surface 133 of the conductive lip 131. These communication grooves 135 are provided along the axial direction of the sealing device 101 (which coincides with the direction of the axis A of the drive shaft 11), and communicate the space S generated between the conductive lip 131 and the seal lip 141 with the space on the atmosphere side O. Therefore, the communication grooves 135 are provided so as to cross the grease grooves 134, and are also connected to the grease grooves 134 (see Figures 3 and 4(B)).

[0034] As an example, the grease G is filled only in the grease groove 134, and not in the communication groove 135. This causes the grease G to remain in the grease groove 134 and to be less likely to leak into the communication groove 135. Of course, the grease G may be carried into the communication groove 135 by the rotation of the drive shaft 11, but by forming the communication groove 135 to a certain extent wide or deep, it is possible to prevent the grease G from clogging the communication groove 135. As an example, the groove width and depth of the communication groove 135 are determined from the perspective of preventing clogging with grease G.

[0035] 2, the plurality of communication grooves 135 are arranged along the circumferential direction of the seal surface 133 of the conductive lip 131. In this case, the communication grooves 135 may or may not be arranged at equal intervals, and the arrangement pitch is not particularly limited. As will be described later, the communication grooves 135 play a role in preventing negative pressure from occurring in the space S (see FIG. 1) generated between the conductive lip 131 and the seal lip 141, and as long as this role is fulfilled, various embodiments are permissible regarding the shape and size of the communication grooves 135, the number of rows, etc.

[0036] (b) Sealing surface As mentioned above, the seal surface 133 has an axial length sufficient to allow it to make surface contact with the outer peripheral surface of the drive shaft 11. The surface contact referred to here can be contrasted with, for example, the line contact of the seal lip 141 with the drive shaft 11, which will be described later. The concepts of "surface contact" and "line contact" are relative when observing the actual contact state with a contact object such as the drive shaft 11. Even though it is called line contact, this is because, when viewed microscopically, it makes contact with the drive shaft 11 via a surface having a certain area.

[0037] The phenomenon described in this embodiment as surface contact means that the seal surface 133 comes into contact with the drive shaft 11 over a surface large enough to provide grease grooves 134 capable of holding grease G. In this case, the grease G held in the grease grooves 134 must be filled between the seal surface 133 and the drive shaft 11 when the seal surface 133 comes into contact with the drive shaft 11. The axial length of the seal surface 133 is determined from this perspective.

[0038] In this embodiment, as an example, the axial length of the seal surface 133 is set to be equal to or greater than the diameter of the garter spring 132 (see FIGS. 1 and 2). The axial length of the seal surface 133 depends on the groove width, number of grooves, and shape of the grease grooves 134 arranged in the axial direction. For example, the axial length of the seal surface 133 may need to be increased if the groove width of the grease grooves 134 is increased or the number of grooves is increased. Conversely, the axial length may be reduced if the groove width of the grease grooves 134 is decreased or the number of grooves is decreased (see, for example, FIG. 8 showing the third embodiment). The axial length of the seal surface 133 may be the same as the diameter of the garter spring 132 or shorter, as long as the grease grooves 134 can be provided.

[0039] 1 and 2, the axial length of the sealing surface 133, which is slightly larger than the diameter of the garter spring 132, is not necessarily a length that is determined when three grease grooves 134 are provided. Even when three grease grooves 134 are provided, the axial length of the sealing surface 133 varies depending on factors such as the groove width and groove shape of the grease groove 134, and it may be the same as the diameter of the garter spring 132 or shorter, for example.

[0040] (c) Grease supply section The sealing device 101 of this embodiment has grease G as an essential element. In other words, the grease groove 134 holds grease G in advance so that the grease G can be filled between the seal surface 133 and the drive shaft 11. Therefore, the sealing structure of the sealing device 101 holds grease G in advance in the grease groove 134 provided in the seal surface 133, and constitutes a grease supply section 136 that fills the grease G between the seal surface 133 and the drive shaft 11.

[0041] (6) Seal lip The seal lip 141 has a triangular cross section and has an annular lip portion 143 at its tip 141a. The lip portion 143 seals the outer circumferential surface of the drive shaft 11 through line contact. Due to this structure, the seal lip 141 is not a tongue-type seal that bends upon contact with the object to be sealed and uses a predetermined area extending from the tip toward the base as a sealing surface, but rather a seal that presses the tip 141a perpendicularly against the object to be sealed (drive shaft 11). What differs from the conductive lip 131 is that the lip portion 143 makes line contact with the drive shaft 11 rather than surface contact with the sealing surface 133.

[0042] The seal lip 141 has an inner surface 144 on the inner side I of the lip portion 143, and an atmospheric surface 145 on the atmospheric side O facing the conductive lip 131. The atmospheric surface 145 is provided with a plurality of thread grooves 146 as a fluid return portion. These thread grooves 146 are grooves that start from the lip portion 143 and are inclined along the rotation direction of the drive shaft 11. When the drive shaft 11 rotates, the thread grooves 146 generate an airflow from the atmospheric surface 145 side toward the inner surface 144 side, and produce a screw pump action that pushes back to the inner side I any sealed fluid (not shown) that has leaked beyond the lip portion 143 to the atmospheric side O.

[0043] (7) Continuity circuit The seal body 121 of the sealing device 101 is an integral structure made of conductive rubber. Therefore, a conductive circuit 151 (see FIG. 1) is formed from the conductive lip 131 and seal lip 141 that contact the drive shaft 11, through the outer circumferential seal 122, and to the housing 12. At this time, a film of grease G is interposed between the seal surface 133 of the conductive lip 131 and the outer circumferential surface of the drive shaft 11, and since the grease G is also conductive, it forms part of the conductive circuit 151.

[0044] 2. Action and Effects In such a configuration, the seal portion 123 of the sealing device 101 brings the conductive lip 131 and the seal lip 141 into contact with the drive shaft 11 to prevent leakage of the fluid (sealed object) from the inside side I. At this time, the seal lip 141 performs a primary sealing function of preventing leakage of the fluid from the inside side I by the lip portion 143. The conductive lip 131 performs a secondary sealing function of blocking the fluid leaking from the seal lip 141 by the seal surface 133. The conductive lip 131 also functions as a dust lip that prevents sludge and foreign matter from entering from the atmosphere side O to the inside side I.

[0045] (1) Electromagnetic noise countermeasures In electric vehicles (EVs), electromagnetic noise is generated by the on / off operation of the inverter that controls the current supplied to the electric motor, or by the induced voltage of the electric motor itself. Electromagnetic noise is transmitted to, for example, the drive shaft 11, which acts as an antenna and is then radiated. Electromagnetic noise radiated in this way can cause communication problems in onboard radios and onboard wireless devices, and can cause various electronic devices to malfunction.

[0046] In the sealing device 101 of this embodiment, the seal body 121 formed from conductive rubber serves as a conductive circuit 151, which directs electromagnetic noise transmitted to the drive shaft 11 to the housing 12. This makes it possible to prevent communication failures and malfunctions.

[0047] At this time, grease G is filled between the seal surface 133 of the conductive lip 131 and the drive shaft 11. For this reason, a film of grease G is interposed between the seal surface 133 and the drive shaft 11, and the conductive grease G plays a part in the conductive circuit 151. For this reason, the seal surface 133 of the conductive lip 131 comes into contact with the drive shaft 11 via the conductive grease G, and electromagnetic noise transmitted to the drive shaft 11 is reliably released to the housing 12.

[0048] (2) Lubrication function The lip portion 143 of the seal lip 141 is lubricated by a fluid such as lubricating oil stored on the inside side I of the machine. In contrast, the seal surface 133 of the conductive lip 131 cannot be expected to be lubricated by the fluid on the inside side I of the machine. Therefore, the sealing device 101 of this embodiment is configured so that a grease groove 134 is provided on the seal surface 133 to hold grease G, and when the drive shaft 11 rotates, the grease G in the grease groove 134 is filled between the seal surface 133 and the drive shaft 11. This allows the seal surface 133 to be lubricated by the grease G, and can protect it from wear and damage.

[0049] Moreover, the seal surface 133 is reliably lubricated and protected by the grease G, even though it employs a seal structure that increases frictional resistance due to surface contact.

[0050] (3) Negative pressure prevention function When the drive shaft 11 rotates, the screw groove 146 provided on the seal lip 141 returns fluid that has leaked from the inside side I past the lip portion 143 to the atmospheric surface 145 to the inside side I by the screw pump action. At the same time, the screw pump action tries to create a negative pressure in the space S between the conducting lip 131 and the seal lip 141. If the space S becomes negative pressure, the conducting lip 131 and the seal lip 141 are attracted to the drive shaft 11, increasing the adhesion force to the drive shaft 11. At this time, abnormal friction occurs in the lip portion 143 of the seal lip 141, not just in the seal surface 133 of the conducting lip 131 where a film of grease G is formed between the conducting lip 131 and the drive shaft 11.

[0051] In this embodiment, when the screw pump action occurs due to the screw groove 146, air on the atmosphere side O is introduced into the space S through the communication groove 135 provided in the seal surface 133 of the conducting lip 131. This prevents the space S from becoming negative pressure, and makes it possible to prevent abnormal friction of the seal lip 141 that would be caused if the space S became negative pressure.

[0052] 3. Another embodiment of the fluid return section Another embodiment of the fluid return portion (thread groove 146) will be described with reference to FIG.

[0053] In the above embodiment, a configuration has been exemplified in which a plurality of thread grooves 146 are provided on the atmospheric surface 145 as a fluid return section that returns fluid that has leaked from the aircraft interior side I to the atmospheric surface 145 by the screw pump action. However, the fluid return section is not limited to the thread grooves 146, and can also be realized by a screw protrusion 147.

[0054] 5, in this embodiment, a plurality of threaded projections 147 are provided on the atmospheric surface 145 of the seal lip 141. These threaded projections 147 are projections that start from the lip portion 143 and are inclined along the rotation direction of the drive shaft 11. When the drive shaft 11 rotates, these threaded projections 147 generate an airflow from the atmospheric side O toward the interior side I, and produce a screw pump action that pushes back to the interior side I any fluid (not shown) that has leaked over the lip portion 143 into the atmospheric side O.

[0055] [Second embodiment] The second embodiment will be described with reference to Figures 6 and 7. The same parts as those in the first embodiment are the same. sign and the explanation will be omitted.

[0056] 1. Configuration In this embodiment, the reinforcing ring 111 has an L-shaped cross section. A support piece 111c is bent at a right angle from the fixed piece 111a, and no bent piece 111b (see FIGS. 1 and 2) is provided.

[0057] Due to the shape of the reinforcing ring 111, the seal portion 123 does not branch into a T-shape from the support piece 111c as in the first embodiment (see FIGS. 1 and 2), but only the portion that forms the conductive lip 131 is bent into an L-shape. As a result, the seal lip 141 is provided at a position near the end of the support piece 111c.

[0058] Similar to the conductive lip 131, the seal lip 141 of this embodiment has a planar seal surface 148 that contacts the drive shaft 11. However, unlike the seal surface 133 of the conductive lip 131, the seal surface 148 of the seal lip 141 is not provided with the grease groove 134 or the communication groove 135.

[0059] Also, unlike the seal lip 141 of the first embodiment, the seal lip 141 of this embodiment is not provided with a thread groove 146 or a thread protrusion 147. In other words, the seal lip 141 is not provided with a fluid return portion that exerts a screw pump action. Therefore, the space S generated between the conducting lip 131 and the seal lip 141 does not become negative pressure, and therefore the seal surface 133 of the conducting lip 131 is not provided with a communication groove 135.

[0060] 2. Action and Effects In this configuration, the seal portion 123 of the sealing device 101 brings the conductive lip 131 and the seal lip 141 into contact with the drive shaft 11 to prevent leakage of fluid (sealed object) from the inside side I. At this time, the seal lip 141 performs a primary sealing function of preventing leakage of fluid from the inside side I by the seal surface 148. The conductive lip 131 performs a secondary sealing function of blocking fluid that has leaked from the seal lip 141 by the seal surface 133. The conductive lip 131 also functions as a dust lip that prevents sludge and foreign matter from entering from the atmosphere side O to the inside side I.

[0061] The electromagnetic noise countermeasures and lubrication functions are the same as those in the first embodiment.

[0062] [Third embodiment] The third embodiment will be described with reference to Fig. 8. The same parts as those in the first embodiment are the same. sign and the explanation will be omitted.

[0063] 1. Configuration The sealing device 101 of this embodiment is used in the drive system of an electric vehicle (EV), for example, in a differential device. Therefore, one of the two relatively displaceable members is a differential case (not shown), and the other is an axle (not shown). The sealing device 101 is fixedly attached to the differential case by fitting an outer circumferential seal 122 reinforced by a fixing piece 111a of a reinforcing ring 111 into an axial hole (not shown) of the differential case.

[0064] The major differences between this embodiment and the first embodiment are that the seal lip 141 is not provided, the conductive lip 131 replaces the seal lip 141, and that a dust lip 161 and a side lip 171 are provided.

[0065] Similar to the first embodiment, the reinforcing ring 111 has a fixed piece 111a, a bent piece 111b, and a support piece 111c. However, the bent piece 111b is bent at a right angle from the fixed piece 111a and passes to the support piece 111c without bending midway. The support piece 111c is bent at an angle of about 80 degrees from the bent piece 111b in a direction facing the fixed piece 111a, and the end is further bent in a direction perpendicular to the axial direction.

[0066] The seal body 121, which is provided to cover the front and back surfaces of the reinforcing ring 111, extends further diagonally from the support piece 111c and has a conductive lip 131 formed at its tip. The conductive lip 131 has a configuration basically similar to that of the first embodiment. The only differences from the first embodiment are that there is only one grease groove 134 and that the connecting groove 135 is not provided.

[0067] The conducting lip 131 is disposed at a position separating the inside side I from the atmosphere side O, and is in contact with the fluid on the inside side I.

[0068] The seal body 121, which covers the support piece 111c of the reinforcing ring 111, is integrally formed with two dust lips 161 and one side lip 171. The two dust lips 161 are inclined toward the atmosphere side O. The side lip 171 extends further toward the atmosphere side O than the dust lips 161 and is inclined radially outward.

[0069] 2. Action and Effects In such a configuration, the seal portion 123 of the sealing device 101 brings the conductive lip 131 into contact with the axle (not shown) to prevent leakage of fluid (sealed object) from the inside side I. The dust lip 161 and the side lip 171 prevent sludge and foreign matter from entering from the atmosphere side O to the inside side I.

[0070] The electromagnetic noise countermeasures and lubrication functions are the same as those in the first embodiment. [Explanation of symbols]

[0071] 11 Drive shaft (another part) 12 Housing (one of the components) 13 Gap 14 Shaft hole 101 Sealing device 111 Reinforcement ring 111a Fixed piece 111b Bent piece 111c Support piece 121 Seal body 122 Periphery seal 123 Seal part 131 Conductive Lip 131a Tip 132 Garter Spring 133 sealing surface 134 Grease groove 135 Connecting Ditch 136 Grease supply unit 141 Seal lip 141a Tip 142 Garter Spring 143 Lip 144 Inside the aircraft 145 Atmospheric Surface 146 Thread groove (fluid return part) 147 Screw protrusion (fluid return part) 148 sealing surface 151 Continuity circuit 161 Dust Trip 171 Side lip A-axis Grease I Inside the aircraft O Atmospheric side S space

Claims

1. a seal body made of conductive rubber, the seal body being fixed in contact with one of two relatively displaceable members that house an object to be sealed, the seal body having an integral annular conductive lip that seals the object by contacting the other of the two members at its tip; a sealing surface provided at a tip of the conductive lip and in surface contact with the other one of the members; a conductive grease filled between the sealing surface and the other member; a grease groove provided on the sealing surface to hold the grease; Equipped with the seal body has an annular seal lip that contacts and seals with the other one of the members and is integral with the seal body on an inboard side of the conducting lip, a fluid return section that returns fluid leaking from the inside of the aircraft to the atmosphere-side surface of the seal lip by a screw pump action, The conductive lip has a communication groove that communicates a space on the seal lip side with a space on the atmosphere side. Sealing device.

2. a seal body made of conductive rubber, the seal body being fixed in contact with one of two relatively displaceable members that house an object to be sealed, the seal body having an integral annular conductive lip that seals the object by contacting the other of the two members at its tip; a sealing surface provided at a tip of the conductive lip and in surface contact with the other one of the members; a grease groove provided on the sealing surface and holding conductive grease in advance so that the grease can be filled between the sealing surface and the other member; Equipped with the seal body has an annular seal lip that contacts and seals with the other one of the members and is integral with the seal body on an inboard side of the conducting lip, a fluid return section that returns fluid leaking from the inside of the aircraft to the atmosphere-side surface of the seal lip by a screw pump action, The conductive lip has a communication groove that communicates a space on the seal lip side with a space on the atmosphere side. Sealing device.

3. a seal body made of conductive rubber, the seal body being fixed in contact with one of two relatively displaceable members that house an object to be sealed, the seal body having an integral annular conductive lip that seals the object by contacting the other of the two members at its tip; a sealing surface provided at a tip of the conductive lip and in surface contact with the other one of the members; a grease supply unit configured to hold conductive grease in a grease groove provided on the sealing surface in advance and to fill the grease between the sealing surface and the other member; Equipped with the seal body has an annular seal lip that contacts and seals with the other one of the members and is integral with the seal body on an inboard side of the conducting lip, a fluid return section that returns fluid leaking from the inside of the aircraft to the atmosphere-side surface of the seal lip by a screw pump action, The conductive lip has a communication groove that communicates a space on the seal lip side with a space on the atmosphere side. Sealing device.

4. The conductive lip has the sealing surface at a tip end thereof.

4. The sealing device according to claim 1.

5. The grease groove is provided along the circumferential direction of the seal surface. The sealing device according to claim 4.

6. The fluid return portion is a thread groove provided on the atmosphere side surface of the seal lip.

4. The sealing device according to claim 1.

7. The fluid return portion is a threaded protrusion provided on the atmosphere side surface of the seal lip.

4. The sealing device according to claim 1.

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