Conductive sealing device

Abstract

The present invention provides a sealing device capable of maintaining conductive performance even for an inner peripheral member rotating at a high speed. A sealing device (1) is provided with a conductive elastic body part (2) which is an annular member and has a portion formed of an elastic material having conductivity. The conductive elastic body part (2) can be in contact with a shaft (101) and a housing (102) of an electric motor. The conductive elastic body part (2) can form a conductive circuit (3) between a shaft (101) and a housing (102) of the electric motor. During rotation of the shaft (101) of the electric motor at a circumferential speed of 60 m / s or less, the impedance of the conductive circuit (3) is 0.01-100 Omega.

Description

Technical Field

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

[0002] For example, in a vehicle equipped with an electric motor such as an electric vehicle (EV), electromagnetic wave noise may be generated due to, for example, induced current generated by the motor. Such electromagnetic wave noise may cause communication interference to an AM radio or other wireless communication devices. In addition, due to such electromagnetic wave noise, electrocorrosion may sometimes occur on metal components such as bearings. Therefore, research has been conducted to remove such electromagnetic wave noise. For example, a technique has been disclosed in which an oil seal for sealing a rotating shaft of a motor is made of a conductive rubber, and the electromagnetic wave noise is released from the rotating shaft to the housing (for example, refer to Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-244180 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] Regarding the conventional oil seal having such a conductive rubber for solving the problems caused by electromagnetic wave noise, a structure is required that can maintain the conductive performance even for a rotating shaft rotating at a higher speed.

[0008] An object of the present invention is to provide a sealing device that can maintain the conductive performance even for an inner peripheral side member rotating at a high speed.

[0009] Means for Solving the Problems

[0010] In order to solve the above problems, the sealing device according to the present invention is for sealing an annular space between an inner peripheral side member and an outer peripheral side member that rotate relative to each other, and is characterized by including: a conductive elastomer portion that is a member annularly surrounding an axis and has a portion formed of an elastic material having conductivity, the conductive elastomer portion can contact the inner peripheral side member and the outer peripheral side member, can form a conductive circuit between the inner peripheral side member and the outer peripheral side member, and in the relative rotation with a circumferential speed of 60 m / s or less, the impedance of the conductive circuit is 0.01 Ω or more and 100 Ω or less.

[0011] In the sealing device according to one aspect of the present invention, even when the conductive circuit is subjected to a force that eliminates the contact between the conductive elastomer portion and the inner peripheral side member caused by the relative rotation, it maintains electrical contact with the inner peripheral side member.

[0012] In the sealing device according to one aspect of the present invention, the conductive elastomer portion has a heat resistance of -40° or more and 200° or less.

[0013] In the sealing device according to one aspect of the present invention, the conductive elastomer portion has a conduction lip that is formed to be able to contact the inner peripheral side member and is annular around the axis. The sealing device further has a lubricant that is interposed between the conduction lip and the inner peripheral side member and has conductivity.

[0014] In the sealing device according to one aspect of the present invention, the conduction lip has at least one groove for holding the lubricant. The groove is an annular groove around the axis and is formed in a portion of the conduction lip that contacts the inner peripheral side member.

[0015] In the sealing device according to one aspect of the present invention, it further includes: a sealing device main body portion that seals the annular space and is an annular member around the axis, and the conductive elastomer portion can be mounted on the sealing device main body portion.

[0016] In the sealing device according to one aspect of the present invention, the conductive elastomer portion has an annular reinforcing ring and a main body portion formed of the conductive elastic material mounted on the reinforcing ring. The main body portion has a conduction lip that is formed to be able to contact the inner peripheral side member and is annular around the axis. The conduction lip is provided on the inner peripheral side of a portion on the inner peripheral side of the reinforcing ring.

[0017] Advantages of the Invention

[0018] According to the sealing device of the present invention, electrical conductivity can be maintained even for a high-speed rotating inner peripheral side member. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a partial cross-sectional view of the sealing device according to the first embodiment of the present invention disposed in an annular space between a relatively rotating inner peripheral side member and an outer peripheral side member.

[0020] Figure 2 is Figure 1 a partial perspective view of the shown sealing device.

[0021] Figure 3It is a schematic diagram showing a part of the contact surface of the conduction lip observed from the inner peripheral side.

[0022] Figure 4 It is a cross-sectional view of the conduction lip. Figure 4 (A) of Figure 3 is a cross-sectional view taken along line A-A of Figure 4 (B) of Figure 3 is a cross-sectional view taken along line B-B of

[0023] Figure 5 It is a schematic diagram showing a thread projection which is a modified example of the thread groove of the sealing device shown as Figure 1

[0024] Figure 6 It is a graph showing the conductivity of the rotating shaft with respect to the circumferential speed of the sealing device according to an embodiment of the present invention.

[0025] Figure 7 It is a schematic diagram showing an example of an impedance measuring device for measuring the impedance of the conductive circuit of the sealing device.

[0026] Figure 8 It is a partial cross-sectional view of the sealing device according to the second embodiment of the present invention disposed in the annular space between the inner peripheral side member and the outer peripheral side member that rotate relative to each other.

[0027] Figure 9 It is Figure 8 a partial perspective view of the sealing device shown as

[0028] Figure 10 It is a cross-sectional view along the axis for showing the general structure of the sealing device according to the third embodiment of the present invention.

[0029] Figure 11 It is along Figure 10 a cross-sectional view along the axis of the conductive elastomer portion of the sealing device shown as

[0030] Figure 12 It is disposed in the annular space between the inner peripheral side member and the outer peripheral side member that rotate relative to each other Figure 10 a partial cross-sectional view of the sealing device shown as

[0031] Figure 13 It is a partial perspective view of the sealing device according to the fourth embodiment of the present invention.

[0032] Figure 14 It is a partial perspective view of the sealing device according to the fifth embodiment of the present invention. Detailed Description of the Invention

[0033] ​Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0034] Figure 1 FIG. 4 is a partial cross-sectional view of a sealing device 1 according to a first embodiment of the present invention disposed in an annular space between an inner peripheral member and an outer peripheral member that rotate relative to each other. Figure 2 is Figure 1 a partial perspective view of the sealing device 1 shown in FIG. 4. In addition, in Figure 1 FIG. 5, a cross-section along the axis x of the sealing device 1 (hereinafter, also simply referred to as "cross-section") on one side with respect to the axis x is shown, and in Figure 2 FIG. 6, a state in which a part of the sealing device 1 is cut in a plane along the axis x is shown. The sealing device 1 according to the present embodiment is used, for example, in electric vehicles (EVs) such as battery electric vehicles (BEVs), hybrid vehicles (HVs), and fuel cell vehicles (FCVs), to seal an annular space between an inner peripheral member and an outer peripheral member that rotate relative to each other. The inner peripheral member and the outer peripheral member are, for example, components of a drive device including an electric motor. The inner peripheral member is, for example, a rotating shaft of the electric motor, and the outer peripheral member is, for example, a housing of the drive device through which the rotating shaft of the electric motor passes. In the present embodiment, as Figure 1 shown in FIG. 7, the sealing device 1 seals an annular space 104 between the rotating shaft 101 of an electric motor (not shown) of a drive device (not shown) and the housing 102 of the drive device. In addition, the application object of the sealing device 1 is not limited to such a drive device.

[0035] As Figure 1 , Figure 2 shown in FIGS. 8 and 9, the sealing device 1 includes a conductive elastomer portion 2, which is a member annularly surrounding the axis x and has a portion formed of a conductive elastic material. The conductive elastomer portion 2 can be in contact with the shaft 101 and the housing 102 of the electric motor. In addition, the conductive elastomer portion 2 can form a conductive circuit 3 between the shaft 101 and the housing 102 of the electric motor. During the rotation of the shaft 101 of the electric motor with a circumferential speed of 60 m / s or less, the impedance of the conductive circuit 3 is 0.01 Ω or more and 100 Ω or less. Hereinafter, the structure of the sealing device 1 will be specifically described.

[0036] Even when a force that eliminates the contact between the conductive elastomer portion 2 and the shaft 101 due to the rotation of the shaft 101 of the electric motor is applied, the conductive elastomer portion 2 maintains electrical contact with the shaft 101. In the case of a so-called radial type conduction lip formed of a conductive elastic material in the prior art, when the rotation shaft of the applicable object rotates at a high speed, a force that acts to eliminate the contact between the conduction lip and the rotation shaft is received from the high-speed rotating shaft. When the rotation shaft rotates at a high speed such as a circumferential speed of 30 m / s or more, a force that eliminates this contact is received, and the contact area between the radial type existing conduction lip and the rotation shaft sometimes becomes smaller. Therefore, when the rotation shaft rotates at a high speed such as a circumferential speed of 30 m / s or more, in the radial type existing conduction lip, the conductivity between the conduction lip and the rotation shaft sometimes decreases. In addition, the circumferential speed of the rotation shaft is the distance that the outer peripheral surface of the rotation shaft moves per unit time. More specifically, the circumferential speed of the rotation shaft is the distance that a point on the outer peripheral surface of the rotation shaft moves per unit time.

[0037] In contrast, the sealing device 1 can maintain electrical contact between the conductive elastomer portion 2 and the shaft 101 even when the shaft 101 rotates at a high speed by filling a lubricant such as a conductive grease. The impedance of the conductive circuit 3 formed by the conductive elastomer portion 2 is 0.01 Ω or more and 100 Ω or less even when the shaft 101 of the electric motor rotates at a circumferential speed of 60 m / s or less. In this way, the sealing device 1 can keep the impedance in the range of 0.01 Ω or more and 100 Ω or less even when the shaft 101 of the electric motor rotates at a high speed, and can suppress the decrease in conductivity.

[0038] As Figure 1 、 Figure 2 shown, the sealing device 1 has an annular shape around the axis x and is installed in the annular space 104 between the through hole 103 provided in the housing 102 and the shaft 101 of the electric motor that passes through the through hole 103 and exits from the housing 102, and seals the space 104. Thereby, the sealing device 1 prevents the sealing object such as lubricating oil existing in the housing 102 from leaking to the atmosphere side. In the illustrated example, as Figure 1 shown, the side indicated by the reference numeral I is the sealing object side, and the side indicated by the reference numeral O is the atmosphere side. In addition, as Figure 1 shown, the axis x of the sealing device 1 installed in the space 104 coincides with or substantially coincides with the axis of the shaft 101. In the illustrated example, the axis x of the sealing device 1 coincides with the axis of the shaft 101.

[0039] The sealing device 1 has a metal component, i.e., a reinforcing ring 10, that is annular around the axis x, and a component installed on the reinforcing ring 10, i.e., a sealing main body 20 that is a conductive elastomer portion 2. For example, as Figure 1 、 Figure 2As shown, the reinforcing ring 10 has: a cylindrical portion 11, which is a cylindrical part extending along the axis x; a bent portion 12, which is an annular part that turns back from the end portion (end portion 11a) on the atmosphere side O of the cylindrical portion 11 toward the object to be sealed side I; and a circular ring portion 13, which is a circular ring part extending inward from the end portion (end portion 12a) on the inner peripheral side of the bent portion 12. The cylindrical portion 11, the bent portion 12, and the circular ring portion 13 are parts of the reinforcing ring 10 integrally formed from the same metallic material. The reinforcing ring 10 is formed, for example, by stamping a ring-shaped metal plate. For example, as Figure 1 shown, the cylindrical portion 11 is a cylindrical or substantially cylindrical part centered on or having the axis x as a substantially central axis, and in a use state where the sealing device 1 is installed in the through hole 103 of the housing 102, it becomes a shape for fixing the sealing device 1 to the through hole 103. In addition, the material of the reinforcing ring 10 is not limited to metallic materials.

[0040] The sealing main body 20 is formed of a conductive elastic material, and the conductive elastic material is crosslinked and bonded to the reinforcing ring 10 to be integrally formed. The sealing main body 20 is, for example, a molded body obtained by insert molding with the reinforcing ring 10 as an insert member. The conductive elastic material forming the sealing main body 20 is, for example, conductive rubber. Additionally, the conductive elastic material forming the sealing main body 20 is, for example, a material having heat resistance of -40° or more and 200° or less, for example, conductive fluororubber (FKM). For example, as Figure 1 , Figure 2 shown, the sealing main body 20 is mounted on the reinforcing ring 10 so as to cover the entire reinforcing ring 10, and has a sealing portion 21, a base portion 22, a gasket portion 23, and a cover portion 24. The sealing portion 21 has a conducting lip 30 and a sealing lip 40. In addition, the sealing portion 21, the base portion 22, the gasket portion 23, and the cover portion 24 are parts of the sealing main body 20 integrally formed from the same material.

[0041] The base portion 22 is a part located at the inner peripheral side end portion of the circular ring portion 13 of the reinforcing ring 10 and its vicinity. The gasket portion 23 is a part covering the outer peripheral surface 11b of the cylindrical portion 11 of the reinforcing ring 10. The cover portion 24 is a part covering the reinforcing ring 10 between the base portion 22 and the gasket portion 23. The outer diameter of the gasket portion 23 is the same as or larger than the diameter of the inner peripheral surface 103a of the through hole 103 of the housing 102. Therefore, when the sealing device 1 is installed in the space 104 of the housing 102, the gasket portion 23 is compressed in the radial direction between the cylindrical portion 11 of the reinforcing ring 10 and the housing 102, the sealing device 1 is fixed to the housing 102, and the inner peripheral surface 103a of the through hole 103 of the housing 102 and the sealing device 1 are sealed.

[0042] As described above, as Figure 1 , Figure 2As shown, the sealing portion 21 is a portion that branches into two strands from the base portion 22, and has a conduction lip portion 30 and a sealing lip portion 40 that extend away from each other along the axis x. The conduction lip portion 30 extends from the end on the atmosphere side O of the base portion 22 toward the atmosphere side O in a manner capable of contacting the outer peripheral surface 101a of the shaft 101. In addition, the sealing lip portion 40 extends from the end on the object to be sealed side I of the base portion 22 toward the object to be sealed side I in a manner capable of contacting the outer peripheral surface 101a of the shaft 101. The conduction lip portion 30 extends, for example, parallel or substantially parallel to the axis x. In addition, the sealing lip portion 40 extends, for example, parallel or substantially parallel to the axis x.

[0043] As Figure 1 , 2 shown, the sealing lip portion 40 has a sealing lip 41 at the end on the object to be sealed side I. The sealing lip 41 is a portion that extends along a circle or a substantially circular ring centered or substantially centered on the axis x, and has a wedge-shaped cross-sectional shape that bulges toward the inner peripheral side. The sealing lip portion 40 has a form in which the sealing lip 41 contacts the outer peripheral surface 101a of the shaft 101.

[0044] Specifically, for example, as Figure 2 shown, the sealing lip 41 has a sealing object side surface 42 and an atmosphere side surface 43 that form the above-described wedge-shaped cross section. The sealing object side surface 42 is an annular surface facing the inner peripheral side and the object to be sealed side I, and the atmosphere side surface 43 is an annular surface facing the inner peripheral side and the atmosphere side O. As Figure 1 , 2 shown, the sealing object side surface 42 and the atmosphere side surface 43 intersect with each other on the inner peripheral side, and a front end 44 in the shape of a circle or a substantially circular ring is formed at the intersection.

[0045] A plurality of thread grooves 45 as fluid return portions are provided on the atmosphere side surface 43. These thread grooves 45 are grooves recessed from the atmosphere side surface 43, and are grooves that are inclined in the rotational direction of the shaft 101 starting from the front end 44. The thread grooves 45 generate an air flow from the atmosphere side surface 43 side toward the sealing object side surface 42 side by the rotation of the shaft 101, and generate a screw pump action that returns the object to be sealed (not shown) that has oozed out beyond the front end 44 to the atmosphere side O to the object to be sealed side I. In addition, the atmosphere side surface 43 may have Figure 5 shown thread protrusions 46 instead of the thread grooves 45. The thread protrusions 46 are protrusions protruding from the atmosphere side surface 43, and are protrusions that are inclined in the rotational direction of the shaft 101 starting from the front end portion 44.

[0046] As Figure 1 , 2As shown, the sealing lip portion 40 is formed such that the sealing lip 41 has a prescribed interference amount at and near the front end 44 and contacts the outer peripheral surface 101a of the shaft 101. Further, on the sealing lip portion 40, a clamping spring 47 is provided at a position facing away from the sealing lip 41. The clamping spring 47 applies a tightening force to the sealing lip portion 40 that presses the sealing lip 41 toward the inner peripheral side, increasing the tightening force that presses the sealing lip 41 against the outer peripheral surface 101a of the shaft 101.

[0047] For example, as Figure 1 , Figure 2 shown, the conducting lip portion 30 has a conducting lip 31 at the end on the atmosphere side O. The conducting lip 31 is a portion that extends along a circular ring or a substantially circular ring centered on or substantially centered on the axis x, and the cross-sectional shape is, for example, a rectangle or a trapezoid that protrudes toward the inner peripheral side. The conducting lip portion 30 has a configuration in which the conducting lip 31 contacts the outer peripheral surface 101a of the shaft 101.

[0048] Specifically, for example, as Figure 1 and Figure 2 shown, the conducting lip 31 has an annular contact surface 32 that forms the above-described rectangular or trapezoidal cross-section. The contact surface 32 is in surface contact with the outer peripheral surface 101a of the shaft 101 and is, for example, a cylindrical surface or a substantially cylindrical surface centered on the axis x or substantially centered on the axis x. The contact surface 32 is not limited to a cylindrical surface or a substantially cylindrical surface and may also be a surface of other shapes. The contact surface 32 may, for example, also be an annular surface that depicts a convex curved line toward the inner peripheral side in cross-section. In this case, in the use state, the contact surface 32 deforms along the outer peripheral surface 101a of the shaft 101, thereby enabling the contact area with the outer peripheral surface 101a of the shaft 101 to be enlarged or maintained.

[0049] Figure 3 is a schematic view showing a part of the contact surface 32 of the conducting lip 31 as viewed from the inner peripheral side, Figure 4 of (A) is a cross-sectional view taken along line A-A of Figure 3 , Figure 4 of (B) is a cross-sectional view taken along line B-B of Figure 3 . As Figure 2 , Figure 3 , Figure 4 of (A), Figure 4 of (B) shown, a plurality of annular grease grooves 33 are provided around the axis x on the contact surface 32. As Figure 4 of (A), Figure 4As shown in (B), the grease groove 33 is a groove that is recessed from the contact surface 32 toward the outer peripheral side, and is, for example, an annular groove that extends along a circle or a substantially circular ring with the axis x as the central axis or a substantially central axis. Further, the grease grooves 33 are provided, for example, at equal intervals or substantially equal intervals in the direction of the axis x. In the illustrated example, three grease grooves 33 are provided, but the number of grease grooves 33 is not limited to three, and may be one or two, or four or more.

[0050] As Figure 3 , Figure 4 shown in (A) of Figure 4 and (B) of Figure 4 , grease G as a lubricant is accommodated and held in the grease groove 33. The grease G held in the grease groove 33 is a conductive grease. The shape of the grease groove 33 is preferably adapted to the shape of holding the grease G. For example, the depth of the grease groove 33 is preferably a depth capable of holding the grease G. Further, the cross-sectional shape of the grease groove 33 is, for example, a parabolic shape as shown in (A) of Figure 4 and (B) of

[0051] . In addition, the cross-sectional shape of the grease groove 33 is not limited to the parabolic shape, and may be other shapes such as a rectangular shape or a curved shape. Figure 2 , Figure 3 , Figure 4 Further, as shown in (B) of Figure 1 , a plurality of connection grooves 34 are provided on the contact surface 32 of the conduction lip 31. The connection groove 34 is a groove that extends along the axis x over the entire width of the contact surface 32 in the direction of the axis x and is recessed from the contact surface 32 toward the outer peripheral side, and intersects and communicates with the grease groove 33, and connects the space S (refer to

[0052]

[0053] Figure 1 As will be described later, the connection groove 34 serves to suppress the space S generated between the shaft 101, the conduction lip portion 30, and the seal lip portion 40 (refer to Figure 1)Function of becoming a negative pressure. As long as it functions to suppress the space S from becoming a negative pressure, the shape, size, quantity, etc. of the connection groove 34, that is, the form of the connection groove 34, can be various forms.

[0054] As Figure 1 , Figure 2 , Figure 4 of (A), Figure 4 As shown in (B), on the conduction lip part 30, a clamping spring 35 is provided at a position opposite to the conduction lip 31. The clamping spring 35 applies a tightening force to the conduction lip part 30 to push the conduction lip 31 toward the inner peripheral side, increasing the tightening force pressing the conduction lip 31 against the outer peripheral surface 101a of the shaft 101.

[0055] As described above, the contact surface 32 of the conduction lip 31 is in surface contact with the outer peripheral surface 101a of the shaft 101. Thus, as will be described later, when the contact surface 32 contacts the outer peripheral surface 101a of the shaft 101, the grease G held in the grease groove 33 is filled between the two. Therefore, the width (axial length) of the contact surface 32 of the conduction lip 31 in the axis x direction is preferably set such that the expansion (area), filling rate, etc. of the grease G filled between the contact surface 32 and the outer peripheral surface 101a of the shaft 101 result in a preferable value for the conductivity between the conduction lip 31 and the shaft 101 described later.

[0056] For example, the axial length of the contact surface 32 is set based on the groove width, quantity, or shape of the grease grooves 33 arranged in the axis x direction. As Figure 1 , Figure 2 , Figure 4 of (A), Figure 4 of (B) shown, in the illustrated example, the axial length of the contact surface 32 of the conduction lip 31 is a length equal to or greater than the diameter dimension of the clamping spring 35. The axial length of the contact surface 32 can be a length equal to the diameter of the clamping spring 35 as long as the grease groove 33 can be provided, or can be a length shorter than the diameter of the clamping spring 35.

[0057] The sealing device 1 is an essential element when using the grease G. Therefore, for example, the grease groove 33 pre-holds the grease G so that the grease G can be filled between the contact surface 32 and the outer peripheral surface 101a of the shaft 101. Thus, the sealing device 1 constitutes a grease supply part 36 that pre-holds the grease G in the grease groove 33 provided on the contact surface 32 and fills the grease G between the contact surface 32 and the outer peripheral surface 101a of the shaft 101.

[0058] The sealing body 20 of the sealing device 1 is an integral structure formed of conductive rubber and covers the reinforcing ring 10. In addition, a thin film of grease G exists between the contact surface 32 of the conductive lip 31 and the outer peripheral surface 101a of the shaft 101. The grease G has conductivity. Therefore, in the sealing device 1, a conductive circuit 3 (see Figure 1 ), the conductive circuit 3 passes through the sealing body 20 including the grease G and the reinforcement ring 10, and reaches the housing 102 from the conducting lip 31 and the sealing lip 41 that are in contact with the shaft 101 via the grease G, via the gasket portion 23. That is, the conductive conductive circuit 3 formed by the conductive elastic body portion 2 (sealing body 20) of the sealing device 1 is composed of the grease G and the sealing body 20, and is also composed of the grease G, the reinforcement ring 10, and the sealing body 20.

[0059] Next, the function of the sealing device 1 having the above structure is described. In the sealing device 1 in the state of use installed between the through hole 103 of the housing 102 of the drive device and the shaft 102, the conductive lip 31 and the sealing lip 41 are in contact with the outer peripheral surface 101a of the shaft 101, and the sealed object is sealed on the sealed object side I to prevent the sealed object from leaking from the sealed object side I. In this seal, the sealing lip 41 plays a main sealing function to prevent the sealed object from leaking from the sealed object side I. The conductive lip 31 plays an auxiliary sealing function to block the sealed object through the seal between the contact surface 32 and the outer peripheral surface 101a of the shaft 101 when the sealed object leaks from the sealing lip 41. The conductive lip 31 also plays a role as a dustproof lip to inhibit foreign matter such as rainwater, muddy water, and dust from entering the sealed object side I from the atmosphere side O.

[0060] In vehicles equipped with electric motors, such as electric vehicles (EVs), electromagnetic wave noise is sometimes generated by the induced current generated by the motor. In addition, electromagnetic wave noise is sometimes generated by the on-off action of an inverter for current control supplied to an electric motor such as an electric motor, or the induced voltage of the motor itself. For example, electromagnetic wave noise is transmitted to shaft 101, and shaft 101 radiates as an antenna. The electromagnetic wave noise radiated in this way will cause communication problems to the car radio or car wireless device, and will also cause various electronic devices to malfunction. In addition, this electromagnetic wave noise sometimes causes electrical corrosion on metal parts.

[0061] In the sealing device 1, the sealing body 20 molded from conductive rubber forms a conductive circuit 3, and allows electromagnetic noise transmitted to the shaft 101 to flow to the housing 102. This can prevent communication failure or malfunction in electronic equipment and electrical corrosion in metal parts.

[0062] As described above, grease G is filled between the contact surface 32 of the conduction lip 31 and the shaft 101, and a film of the grease G is sandwiched between the contact surface 32 and the shaft 101, and the film of the grease G constitutes a part of the conductive circuit 3. Therefore, the gap between the contact surface 32 of the conduction lip 31 and the shaft 101 can be reduced or eliminated, and the conductivity between the contact surface 32 of the conduction lip 31 and the shaft 101 can be improved. As a result, the conduction circuit 3 can increase the flow of electromagnetic wave noise transmitted to the shaft 101 to the housing 102, and can further reduce the occurrence of defects due to electromagnetic wave noise.

[0063] In addition, when the shaft 101 rotates at a high speed, the conduction lip portion 30 is subjected to a force that eliminates the contact between the conduction lip 31 and the shaft 101 due to the rotation of the shaft 101. Therefore, when the shaft 101 rotates at a high speed, for example, when the shaft 101 rotates at a high speed of 30 m / s or more in circumferential speed, sometimes the contact surface 32 of the conduction lip 31 separates from the outer peripheral surface 101a of the shaft 101 to generate a gap. In contrast, in the sealing device 1, grease G is filled between the contact surface 32 of the conduction lip 31 and the outer peripheral surface 101a of the shaft 101, and a film of the grease G exists between the contact surface 32 and the outer peripheral surface 101a of the shaft 101. Therefore, when the shaft 101 rotates at a high speed, even if a gap that cuts off electrical conduction is generated between the contact surface 32 of the conduction lip 31 and the outer peripheral surface 101a of the shaft 101, the gap is filled with the grease G. Therefore, even when the shaft 101 rotates at a high speed, the conductivity between the contact surface 32 of the conduction lip 31 and the shaft 101 can be maintained, and the flow of electromagnetic wave noise transmitted to the shaft 101 to the housing 102 can be maintained.

[0064] Therefore, as Figure 6 shown, in the sealing device 1, during rotation with the circumferential speed of the shaft 101 of the electric motor being 60 m / s or less, the impedance of the conductive circuit 3 can be 0.01 Ω or more and 100 Ω or less. Thus, the sealing device 1 can keep the impedance of the conductive circuit 3 in the range of 0.01 Ω or more and 100 Ω or less even when the shaft 101 of the electric motor rotates at a high speed, and can suppress the decrease in conductivity.

[0065] The impedance of the conductive circuit 3 of the sealing device 1 can be, for example, as Figure 7It is measured by the impedance measurement device 200 shown. The impedance measurement device 200 has an impedance analyzer 201. In the impedance measurement device 200, one terminal of the impedance analyzer 201 is in contact with the shaft 101 via a conductive member 202 such as a copper plate, and the other terminal of the impedance analyzer 201 is fixed to the housing 102 via a conductive member 203. The shaft 101 can slide relative to the conductive member 202. Additionally, in the impedance measurement device 200, a member imitating the shape of the shaft 101 can be used instead of the shaft 101, and similarly, a member imitating the shape of the housing 102 can be used instead of the housing 102.

[0066] The measurement of the impedance of the conductive circuit 3 of the sealing device 1 using the impedance measurement device 200 is performed by rotating the shaft 101 at a rotational speed between 0 and 60 m / s in circumferential speed and detecting the impedance of the conductive circuit 3 at this rotational speed using the impedance analyzer 201. Thus, the impedance of the conductive circuit 3 at the rotational speed of the shaft 101 with a circumferential speed of 0 to 60 m / s can be obtained. As described above, the measured value of the impedance of the conductive circuit 3 at the rotational speed of the shaft 101 with a circumferential speed of 0 to 60 m / s is as Figure 6 shown, 0.01 Ω to 100 Ω.

[0067] The conditions for the impedance measurement device 200 to measure the impedance of the conductive circuit 3 are, for example: the measurement frequency of the impedance analyzer 201 is 500 kHz, and the voltage amplitude is 5 V.

[0068] Additionally, the tip 44 of the sealing lip 41 and its vicinity are lubricated by a sealing object such as lubricating oil on the sealing object side I. In contrast, lubrication of the contact surface 32 of the conduction lip 31 cannot be expected by the sealing object on the sealing object side I. Therefore, the conduction lip 31 of the sealing device 1 is provided with a grease groove 33 on the contact surface 32 to hold the grease G, and when the shaft 101 rotates, the grease G in the grease groove 33 is filled between the shaft 101. Thus, the contact surface 32 can be lubricated with the grease G, protecting the contact surface 32 and the shaft 101 from wear or damage.

[0069] Furthermore, when the shaft 101 rotates, the thread groove 45 or the thread protrusion 46 provided on the sealing lip 41 returns the sealing object that has oozed out beyond the tip 44 to the sealing object side I from the sealing object side I through the action of a thread pump. On the other hand, the action of the thread pump creates a negative pressure in the space S between the shaft 101, the conduction lip portion 30, and the sealing lip portion 40. If it is assumed that the space S becomes negative pressure, the conduction lip 31 and the sealing lip 41 are pressed more strongly against the shaft 101. At this time, especially different from the conduction lip 31, abnormal friction sometimes occurs at the tip 44 of the sealing lip 41 and its vicinity where a grease G film is not formed between the shaft 101.

[0070] In the sealing device 1, when the screw pump action caused by the screw groove 45 or the screw protrusion 46 occurs, the air on the atmosphere side O is introduced into the space S through the connection groove 34 provided on the contact surface 32 of the conduction lip 31. Thus, the space S will not become a negative pressure, or the negative pressure in the space S will not increase, and it is possible to prevent abnormal friction of the sealing lip 41 caused when the space S becomes a negative pressure.

[0071] Next, the sealing device 4 according to the second embodiment of the present invention will be described. Figure 8 FIG. is a partial cross-sectional view of the sealing device 4 according to the second embodiment of the present invention disposed in an annular space between an inner peripheral side member and an outer peripheral side member that rotate relative to each other. Figure 9 is Figure 8 A partial perspective view of the shown sealing device 4. In the present embodiment, the sealing device 4 is the same as the sealing device 1. As Figure 8 shown, the sealing of the annular space 104 between the rotary shaft, i.e., the shaft 101, of an electric motor (not shown) of a driving device (not shown) and the housing 102 of the driving device is achieved. In addition, the applicable object of the sealing device 4 is not limited to such a driving device. Hereinafter, for the sealing device 4, the same reference numerals as those of the sealing device 1 are assigned to the same structures or structures having the same functions, and their descriptions are omitted.

[0072] As Figure 8 、 Figure 9 shown, the sealing device 4 has a reinforcing ring 15 with a different shape from the reinforcing ring 10 of the sealing device 1, and the cross-sectional shape of the reinforcing ring 15 is an L shape. Specifically, for example, the reinforcing ring 15 has a cylindrical portion 11 and an annular portion 16 that extends inwardly to the inner peripheral side from the end portion 11c on the sealing object side I of the cylindrical portion 11.

[0073] In addition, corresponding to the shape of the reinforcing ring 15, the sealing device 4 has a sealing body 25 with a different shape from the sealing body 20 of the sealing device 1. Specifically, for example Figure 8 、 Figure 9 shown, in the sealing body 25 of the sealing device 4, the sealing portion 21 is different from the sealing portion 21 of the sealing device 1 and does not have a sealing lip portion 40 that extends from the base portion 22 to the sealing object side I. In the sealing lip portion 40 of the sealing device 4, a sealing lip 48 is formed at the inner peripheral side end portion of the base portion 22. In addition, the sealing lip portion 40 of the sealing device 4 does not have a clamping spring 47.

[0074] The sealing lip 48 of the sealing device 4, like the conduction lip 31, has a planar sealing surface 49 that can be formed in contact with the shaft 101. For example, as Figure 9As shown, the sealing surface 49 is a cylindrical surface or a substantially cylindrical surface centered on or approximately centered on the axis x. In addition, on the sealing lip 48, different from the contact surface 32 of the conduction lip 31, no grease groove 33 or connection groove 34 is provided. Further, different from the sealing lip 41 of the sealing device 1, neither a thread groove 45 nor a thread protrusion 46 is provided on the sealing lip 48. That is, no fluid return portion that functions as a screw pump is provided on the sealing lip 48. Therefore, in the sealing device 4, since the space S generated between the conduction lip portion 30 and the sealing lip 48 does not become a negative pressure, no connection groove 34 is provided on the contact surface 32 of the conduction lip 31 either. Additionally, a connection groove 34 may be provided on the contact surface 32 of the conduction lip 31 of the sealing device 4.

[0075] The sealing device 4 having the above structure functions in the same manner as the sealing device 1 in terms of electromagnetic wave noise countermeasures and lubrication function. That is, the sealing portion 21 of the sealing device 4 brings the conduction lip 31 and the sealing lip 48 into contact with the shaft 101 to prevent the object to be sealed from leaking from the object to be sealed side I. At this time, the sealing lip 48 functions as the main sealing function to prevent fluid from leaking from the object to be sealed side I through the sealing surface 49. The conduction lip 31 functions as an auxiliary sealing function to block the fluid leaking from the sealing lip 48 through the contact surface 32. In addition, the conduction lip 31 also functions as a dust-proof lip to suppress foreign matter from entering the object to be sealed side I from the atmosphere side O.

[0076] In addition, in the sealing device 4, similar to the sealing device 1, the conductive circuit 3 formed by the conductive elastomer portion 2 (sealing main body 25) is composed of the grease G and the sealing main body 25, and is composed of the grease G, the reinforcing ring 15, and the sealing main body 25, allowing the electromagnetic wave noise transmitted to the shaft 101 to flow to the housing 102. Thereby, it is possible to prevent communication failures or malfunctions from occurring in electronic devices and prevent electrocorrosion from occurring in metal components.

[0077] In the sealing device 4, similar to the sealing device 1, grease G is filled between the contact surface 32 of the conduction lip 31 and the shaft 101, and a coating film of the grease G is sandwiched between the contact surface 32 and the shaft 101. Therefore, it is possible to reduce or eliminate the gap for cutting off electrical conduction between the contact surface 32 of the conduction lip 31 and the shaft 101, and the conductivity between the contact surface 32 of the conduction lip 31 and the shaft 101 can be improved. Thereby, the conduction circuit 3 can increase the flow rate of the electromagnetic wave noise transmitted to the shaft 101 to the housing 102, and can further reduce the occurrence of defects due to electromagnetic wave noise.

[0078] In addition, in the sealing device 4, grease G is also filled between the contact surface 32 of the conduction lip 31 and the outer peripheral surface 101a of the shaft 101, and a film of the grease G is sandwiched between the contact surface 32 and the outer peripheral surface 101a of the shaft 101. Therefore, when the shaft 101 rotates at a high speed, even if a gap is generated between the contact surface 32 of the conduction lip 31 and the outer peripheral surface 101a of the shaft 101, the gap will be filled with the grease G. Therefore, even when the shaft 101 rotates at a high speed, the conductivity between the contact surface 32 of the conduction lip 31 and the shaft 101 can be maintained, and the flow rate of the electromagnetic wave noise transmitted to the shaft 101 to the housing 102 can be maintained.

[0079] Therefore, in the sealing device 4, as Figure 6 shown, during rotation with the circumferential speed of the shaft 101 of the electric motor being 60 m / s or less, the impedance of the conductive circuit 3 can also be 0.01 Ω or more and 100 Ω or less. Thus, even when the shaft 101 of the electric motor rotates at a high speed, the sealing device 4 can keep the impedance of the conductive circuit 3 within the range of 0.01 Ω or more and 100 Ω or less, and can suppress the reduction of conductivity.

[0080] Next, the sealing device 5 according to the third embodiment of the present invention will be described. Figure 10 FIG. is a cross-sectional view along the axis x showing the general structure of the sealing device 5 according to the third embodiment of the present invention, Figure 11 and is a cross-sectional view along the axis x of the conductive elastomer portion 6 of the sealing device 5. In addition, Figure 12 FIG. is a partial cross-sectional view of the sealing device 5 disposed in the annular space between the inner peripheral side member and the outer peripheral side member that rotate relative to each other. In the present embodiment, the sealing device 5 is the same as the sealing device 1, as Figure 12 shown, the sealing of the annular space 104 between the rotating shaft, i.e., the shaft 101, of the electric motor (not shown) of the driving device (not shown) and the housing 102 of the driving device is achieved. In addition, the applicable object of the sealing device 5 is not limited to such a driving device.

[0081] In addition, as Figure 10 , Figure 11 and Figure 12 shown, on one side in the direction of arrow a in the axis x direction (one side in the axial direction) is the atmosphere side O (outer side), and on one side in the direction of arrow b in the axis x direction (the other side in the axial direction) is the sealed object fluid side I (inner side). In addition, in the direction perpendicular to the axis x (radial direction), the side in the direction away from the axis x (direction of arrow c) is the outer peripheral side, and the side in the direction approaching the axis x (direction of arrow d) is the inner peripheral side.

[0082] As Figures 10 to 12As shown, the sealing device 5 is a ring-shaped component around the axis x, and includes a conductive elastomeric portion 6 formed of a conductive elastic material. The conductive elastomeric portion 6 can contact the shaft 101 and the housing 102 of the electric motor. In addition, the conductive elastomeric portion 6 can form a conductive circuit 8 between the shaft 101 and the housing 102 of the electric motor. During the rotation of the shaft 101 of the electric motor with a circumferential speed of 60 m / s or less, the impedance of the conductive circuit 8 is 0.01 Ω or more and 100 Ω or less. Hereinafter, the structure of the sealing device 5 will be specifically described.

[0083] Even when the conductive elastomeric portion 6 is subjected to a force that eliminates the contact between the conductive elastomeric portion 6 and the shaft 101 caused by the rotation of the shaft 101 of the electric motor, it maintains electrical contact with the shaft 101. As described above, in the case of a so-called radial-type conductive lip formed of a conductive elastic material in the prior art, when the rotating shaft of the applicable object rotates at a high speed, a force acts on the high-speed rotating shaft in a manner that eliminates the contact between the conductive lip and the rotating shaft. When the rotating shaft rotates at a high speed such as a circumferential speed of 30 m / s or more, the force that eliminates this contact is received, and the contact area between the radial-type existing conductive lip and the rotating shaft sometimes becomes smaller. Therefore, when the rotating shaft rotates at a high speed such as a circumferential speed of 30 m / s or more, the conductivity between the conductive lip and the rotating shaft sometimes decreases in the radial-type existing conductive lip.

[0084] In contrast, the conductive elastomeric portion 6 of the sealing device 5 can maintain electrical contact between the conductive elastomeric portion 6 and the shaft 101 even when the shaft 101 rotates at a high speed. Even when the shaft 101 of the electric motor rotates at a circumferential speed of 60 m / s or less, the impedance of the conductive circuit 8 formed by the conductive elastomeric portion 6 is 0.01 Ω or more and 100 Ω or less. In this way, even when the shaft 101 of the electric motor rotates at a high speed, the sealing device 5 can keep the impedance in the range of 0.01 Ω or more and 100 Ω or less, and can suppress the decrease in conductivity.

[0085] As Figure 10 shown, the sealing device 5 has a sealing device main body portion 7. The sealing device main body portion 7 includes a reinforcing ring 50 and a component formed of a rubber-like elastomer mounted on the reinforcing ring 50, that is, a sealing main body 60. The reinforcing ring 50 has: a cylindrical portion 51, which is a tubular portion extending along the axis x; a bent portion 52, which is an annular portion that turns back from the end portion (end portion 51a) on the atmospheric side O of the cylindrical portion 51 to the atmospheric side O; and a circular ring portion 53, which is a circular ring portion extending from the inner peripheral side end portion (end portion 52a) of the bent portion 52 to the inner peripheral side. The cylindrical portion 51, the bent portion 52, and the circular ring portion 53 are parts of the reinforcing ring 50 integrally formed of the same metal material. The reinforcing ring 50 is formed, for example, by stamping a ring-shaped metal plate. For example, as Figure 10 、 Figure 12As shown, the cylindrical portion 51 has a cylindrical or substantially cylindrical portion with the axis x as the central axis or substantially central axis, and in the use state where the sealing device 5 is installed in the through hole 103 of the housing 102, it becomes a shape for fixing the sealing device 5 to the through hole 103. In addition, the material of the reinforcing ring 50 is not limited to a metallic material.

[0086] The sealing main body 60 is formed of an elastic material having a lower conductivity than that of the conductive elastic material, specifically, a non-conductive elastic material, and this elastic material is crosslinked and bonded to the reinforcing ring 50 and integrally formed. The sealing main body 60 is, for example, a molded body obtained by insert molding with the reinforcing ring 50 as an insert member. For example, as Figure 10 shown, the sealing main body 60 is mounted on the reinforcing ring 50 so as to cover the entire reinforcing ring 50, and has a sealing portion 61, a base portion 62, a gasket portion 63, and a cover portion 64. In addition, the sealing portion 61 has a sealing lip 65 and a dust-proof lip 66. Further, the sealing portion 61, the base portion 62, the gasket portion 63, and the cover portion 64 are parts of the sealing main body 60 integrally formed of the same material.

[0087] The base portion 62 is a portion located on the inner peripheral side end of the annular portion 53 of the reinforcing ring 50 and its vicinity, the gasket portion 63 is a portion covering the outer peripheral surface 51b of the cylindrical portion 51 of the reinforcing ring 50, and the cover portion 64 is a portion covering the reinforcing ring 50 between the base portion 62 and the gasket portion 63. The gasket portion 63 has a portion (contact portion 63a) having an outer diameter equal to or larger than the inner diameter of the inner peripheral surface 103a of the through hole 103 of the housing 102. Therefore, when the sealing device 5 is installed in the space 104 of the housing 102, the contact portion 63a of the gasket portion 63 is compressed in the radial direction between the cylindrical portion 51 of the reinforcing ring 50 and the housing 102, the sealing device 5 is fixed to the housing 102, and in addition, the inner peripheral surface 103a of the through hole 103 of the housing 102 and the sealing device 5 are sealed.

[0088] In the sealing portion 61, as Figure 10 、 Figure 12 shown, the sealing lip 65 and the dust-proof lip 66 extend from the base portion 62 in opposite directions along the axis x. The sealing lip 65 extends from the end on the sealing object side I of the base portion 62 toward the sealing object side I so as to be able to contact the outer peripheral surface 101a of the shaft 101, for example. The dust-proof lip 66 extends from the end on the atmosphere side O of the base portion 62 toward the atmosphere side O and the inner peripheral side so as to be able to contact the outer peripheral surface 101a of the shaft 101, for example. The sealing lip 65 prevents leakage of the sealing object, and in addition, the dust-proof lip 66 prevents foreign matters such as rainwater, muddy water, and dust from entering the sealing object side I from the atmosphere side O. Further, a clamping spring 67 is mounted on the sealing lip 65, and this clamping spring 67 is used to increase the tightening force for pressing the sealing lip 65 against the outer peripheral surface 101a of the shaft 101.

[0089] As Figure 10 and Figure 11 shown, the conductive elastomer portion 6 has a reinforcing ring 70 and a component mounted on the reinforcing ring 70, namely, a main body portion 80. The main body portion 80 is a component formed of a rubber-like conductive elastic material. The conductive elastic material of the main body portion 80 is, for example, conductive rubber. In addition, the conductive elastic material forming the main body portion 80 is, for example, a material having heat resistance of -40° or more and 200° or less, for example, conductive fluororubber (FKM). The main body portion 80 is integrally formed by crosslinking and bonding the conductive elastic material with the reinforcing ring 70. The main body portion 80 is, for example, a molded body obtained by insert molding with the reinforcing ring 70 as an insert member.

[0090] For example, as Figure 10 、 Figure 11 shown, the reinforcing ring 70 has: a cylindrical portion 71, a cylindrical portion extending along the axis x; and an annular portion 72, an annular portion extending from the end portion (end portion 71a) on the atmosphere side O of the cylindrical portion 71 toward the inner peripheral side. The cylindrical portion 71 and the annular portion 72 are parts of the reinforcing ring 70 integrally formed of the same metal material. The reinforcing ring 70 is formed, for example, by stamping a ring-shaped metal plate. For example, as Figure 10 、 Figure 11 shown, the cylindrical portion 71 has a cylindrical or substantially cylindrical portion with the axis x as the central axis or a substantially central axis, and in the use state where the sealing device 5 is installed in the through hole 103 of the housing 102, it has a shape that fixes the conductive elastomer portion 6 between the sealing device main body portion 7 and the through hole 103. In addition, the material of the reinforcing ring 70 is not limited to a metal material.

[0091] Specifically, as Figure 10 、 Figure 12 shown, in the sealing device 5, the cylindrical portion 71 is located on the outer peripheral side of the cylindrical portion 51 of the reinforcing ring 50 of the sealing device main body portion 7, and has a shape compressed with the gasket portion 63 of the sealing main body 60 sandwiched between it and the cylindrical portion 51 of the reinforcing ring 50. As Figure 10 、 Figure 12 shown, the annular portion 72 has the following shape: in the state where the conductive elastomer portion 6 is assembled to the sealing device main body portion 7 (assembly state), it contacts the cover portion 64 on the atmosphere side O of the sealing main body 60 of the sealing device main body portion 7 from the atmosphere side O. In addition, for example, as Figure 10 、 Figure 12 shown, the annular portion 72 extends more toward the inner peripheral side than the annular portion 53 of the reinforcing ring 50 of the sealing device main body portion 7.

[0092] In addition, the reinforcing ring 70 has a seal device engaging portion 73 in a portion of the atmospheric side O of the seal device 5. The seal device engaging portion 73 is formed to be able to engage the conductive elastomer portion 6 with the seal device main body portion 7. The seal device engaging portion 73 has, for example, a cylindrical portion engaging portion 74 and an annular portion engaging portion 75.

[0093] The cylindrical portion engaging portion 74 is formed to be able to engage, for example, with a part of the gasket portion 63 of the seal main body 60 of the seal device main body portion 7. Specifically, for example, as Figure 10 , Figure 12 shown, in the assembled state where the conductive elastomer portion 6 is assembled to the seal device main body portion 7, the cylindrical portion engaging portion 74 has a shape that can compress the cylindrical portion to-be-engaged portion 63b formed in a portion closer to the atmospheric side O than the contact portion 63a of the gasket portion 63 between the cylindrical portion 51 of the reinforcing ring 50 and engage with the seal device main body portion 7. For example, as Figure 10 , Figure 12 shown, the cylindrical portion engaging portion 63b protrudes outward from the portion (engaged portion 63c) between the contact portion 63a of the gasket portion 63 and the cylindrical portion engaging portion 63b, and does not protrude outward more than the contact portion 63a.

[0094] In addition, for example, a cylindrical portion engaging portion 76 is formed on the cylindrical portion engaging portion 74, and the cylindrical portion engaging portion 76 engages with the gasket portion 63 in the engaged portion 63c of the gasket portion 63. The cylindrical portion engaging portion 76 contacts or faces the engaged portion 63c of the gasket portion 63 from the outer peripheral side in the assembled state, and engages with the cylindrical portion engaging portion 63b in the x-axis direction.

[0095] The annular portion engaging portion 75 is formed to be able to engage, for example, with a portion (atmospheric side cover portion 64a) on the atmospheric side O of the cover portion 64 of the seal main body 60 of the seal device main body portion 7. Specifically, for example, as Figures 10 to 12 shown, the annular portion engaging portion 75 has a shape that can engage with the annular portion to-be-engaged portion 68 formed on the atmospheric side cover portion 64a. Specifically, for example, as Figures 10 to 12 shown, the annular portion engaging portion 75 is a portion that protrudes toward the sealing object side I from the surface (surface 72a) of the annular portion 72 of the reinforcing ring 70 facing the sealing object side I. Specifically, for example, as Figure 10 , Figure 12 shown, the annular portion to-be-engaged portion 68 is a portion that houses the annular portion engaging portion 75 in a manner that can engage with the annular portion engaging portion 75 and is recessed toward the sealing object side I formed on the atmospheric side cover portion 64a. The annular portion engaging portion 75 is housed in the annular portion to-be-engaged portion 68 and engages with the annular portion to-be-engaged portion 68.

[0096] As Figure 11As shown, the main body portion 80 has a conducting lip 81, a base portion 82, and a connecting portion 83. The conducting lip 81, the base portion 82, and the connecting portion 83 are respectively parts of the main body portion 80 formed of the same material. The base portion 82 is the end portion (end portion 72b) of the inner peripheral side of the circular ring portion 72 of the reinforcing ring 70 and the part in its vicinity, and the conducting lip 81 extends from the base portion 82 toward the inner peripheral side.

[0097] As Figure 12 shown, in the sealing device 5 between the through hole 103 of the housing 102 of the driving device and the shaft 101, the conducting lip 81 is formed in contact with the outer peripheral surface 101a of the shaft 102. The conducting lip 81 has a shape with higher rigidity in the radial direction with respect to an external force directed toward the outer peripheral side. For example, as Figure 12 shown, the conducting lip 81 is formed to be located between the end portion 72b of the circular ring portion 72 of the reinforcing ring 70 or the base portion 82 and the radial direction of the outer peripheral surface 101a of the shaft 101, and is formed in a shape with higher rigidity in the radial direction with respect to an external force directed toward the outer peripheral side. In addition, for example, as Figure 10 , Figure 11 shown, in the free state where it is not installed in the driving device, the conducting lip 81 extends from the base portion 82 toward the atmosphere side O (the arrow a direction side) and the inner peripheral side (the arrow d direction side), and the front end portion (front end portion 81a) of the conducting lip 81 extends in the radial direction so as to face the end portion 72b of the circular ring portion 72 of the reinforcing ring 70 or the base portion 82. Additionally, on the conducting lip 81, unevenness may also be provided on the contact surface with the outer peripheral surface 101a of the shaft 101.

[0098] The connecting portion 83 is the part where the conducting lip 81 is formed to be connected to the housing 102 via the base portion 82 in the sealing device 5 between the through hole 103 of the housing 102 of the driving device and the shaft 102. For example, as Figure 11 shown, the connecting portion 83 extends over a part on the atmosphere side O of the surface 72c of the circular ring portion 72 of the reinforcing ring 70 facing the atmosphere side O and the surface 71b of the reinforcing ring 70 facing the outer peripheral side of the cylindrical portion 71. In addition, the end portion (end portion 83a) on the outer peripheral side of the connecting portion 83 can be in contact with the inner peripheral surface 103a of the through hole 103 of the housing 102. For example, as Figure 11 shown, the end portion 83a protrudes more toward the outer peripheral side than the cylindrical portion 71 of the reinforcing ring 70, or protrudes toward the outer peripheral side to the same radial position as the cylindrical portion 71 of the reinforcing ring 70.

[0099] As described above, in the main body portion 80 formed of the conductive elastic material, the conducting lip 81 is in contact with the outer peripheral surface 101a of the shaft 101, and the end portion 83a of the connecting portion 83 is in contact with the inner peripheral surface 103a of the through hole 103 of the housing 102, thereby forming a conductive circuit 8 constituted by the conductive elastic body portion 6 between the shaft 101 and the housing 102.

[0100] Next, the function of the sealing device 5 having the above structure will be described. In the sealing device 5 in the use state between the through hole 103 of the housing 102 of the drive device and the shaft 102, the sealing lip 65 contacts the outer peripheral surface 101a of the shaft 101, seals the object to be sealed on the object to be sealed side I, and prevents the object to be sealed from leaking out from the object to be sealed side I. In addition, in the use state of the sealing device 5, the dust-proof lip 66 contacts the outer peripheral surface 101a of the shaft 101, and prevents foreign matters such as rainwater, muddy water, and dust from entering the object to be sealed side I from the atmosphere side O.

[0101] As described above, in a vehicle equipped with an electric motor such as an electric vehicle (EV), electromagnetic wave noise may be generated due to, for example, induced current generated by the motor. In addition, electromagnetic wave noise may be generated due to the on / off operation of an inverter that supplies current control to the electric motor or the like, or the induced voltage of the electric motor itself. The sealing device 5 is formed of a main body portion 80 made of a conductive elastic material of the conductive elastic body portion 6, and forms a conduction circuit 8, allowing the electromagnetic wave noise transmitted to the shaft 101 to flow to the housing 102. Thereby, it is possible to prevent communication failures or malfunctions in electronic devices and prevent electrolytic corrosion in metal components.

[0102] When the shaft 101 rotates at a high speed, the conduction lip 81 is subjected to a force acting in the direction of eliminating the contact between the conduction lip 81 and the shaft 101 due to the rotation of the shaft 101. However, as described above, the conduction lip 81 has a shape with higher rigidity in the radial direction with respect to an external force directed toward the outer peripheral side. Therefore, when the shaft 101 rotates at a high speed, for example, when the shaft 101 rotates at a high speed with a circumferential speed of 30 m / s or more, a force may act in a direction that creates a gap between the front end portion 81a of the conduction lip 81 and the outer peripheral surface 101a of the shaft 101. However, in the sealing device 5, the conduction lip 81 has higher rigidity in the radial direction with respect to an external force directed toward the outer peripheral side. Therefore, when the shaft 101 rotates at a high speed, a gap that cuts off electrical conduction is prevented from being generated between the contact surface (front end portion 81a) of the conduction lip 81 and the outer peripheral surface 101a of the shaft 101. In this way, even when the shaft 101 rotates at a high speed, the conductivity between the front end portion 81a of the conduction lip 81 and the shaft 101 can be maintained, and the flow rate of the electromagnetic wave noise transmitted to the shaft 101 to the housing 102 can be maintained.

[0103] Therefore, as Figure 6As shown, in the sealing device 5, during rotation with a circumferential speed of the shaft 101 of the electric motor being 60 m / s or less, the impedance of the conductive circuit 8 can be 0.01 Ω or more and 100 Ω or less. Thus, even when the shaft 101 of the electric motor rotates at high speed, the sealing device 5 can keep the impedance of the conductive circuit 8 within the range of 0.01 Ω or more and 100 Ω or less, and can suppress the reduction of conductivity. In addition, the impedance of the conductive circuit 8 of the sealing device 5 can also be measured in the same manner as the sealing device 1. For example, it can be measured by Figure 7 the impedance measuring device 200 shown.

[0104] In addition, according to the sealing device 5, when the sealing device 5 is disposed in the annular space 104 between the shaft 101 and the housing 102, it can be disposed in a state where the conductive elastomer portion 6 and the sealing device main body portion 7 are assembled. Since the main body portion 80 of the conduction lip 81 including the conductive elastomer portion 6 is a molded body formed of a conductive elastic material, compared with the existing conductive sliding members formed of conductive brushes or fibers, the deformation of the main body portion 80 can be suppressed. Therefore, the conductive elastomer portion 6 is easy to install on the sealing device main body portion 7 and is also easy to install in the annular space 104 between the shaft 101 and the housing 102. In addition, the conductive elastomer portion 6 has a cylindrical portion engaging portion 74 and a ring portion engaging portion 75, whereby the installation and positioning on the sealing device main body portion 7 can be facilitated.

[0105] As described above, according to the sealing device 5 according to the third embodiment of the present invention, the conductive performance can be maintained even for the shaft 101 rotating at high speed.

[0106] Next, the sealing device 5A according to the fourth embodiment of the present invention will be described. Hereinafter, the structures having the same or similar functions as the conductive elastomer portion 6 and the sealing device main body portion 7 of the sealing device 5 according to the above-described third embodiment are denoted by the same reference numerals and their descriptions are omitted, and the different structures will be described.

[0107] Figure 13 is a partial perspective view of the sealing device 5A according to the fourth embodiment of the present invention. The sealing device 5A includes a conductive elastomer portion 6A and a sealing device main body portion 7A. As Figure 13 shown, the sealing device 5A is mainly different from the above-described sealing device 5 in the structure of the ring portion engaging portion and the structure of the ring portion to be engaged. Specifically, the ring portion engaging portion 75A of the conductive elastomer portion 6A is provided closer to the inner peripheral side in the conductive elastomer portion 6A. Specifically, for example, as Figure 13As shown, the annular portion joint 75A is formed in the base portion 82 of the main body portion 80 at a position facing the cylindrical portion joint 74 or the cylindrical portion engaging portion 76, and projects outward from the outer peripheral side portion of the end portion on the sealing object side I of the base portion 82. The sealing device main body portion 7A is configured to be able to engage with the annular portion joint 75A of the main body portion 80. Specifically, for example, as Figure 13 shown, the base portion 62 of the sealing main body 60 of the sealing device main body portion 7A has a shape that presses the annular portion joint 75A of the main body portion 80 toward the inner peripheral side direction (arrow d direction) in a state where the conductive elastic body portion 6A and the sealing device main body portion 7A are assembled. That is, an annular portion to-be-joined portion 68A is provided on the base portion 62 of the sealing main body 60 of the sealing device main body portion 7A, and the annular portion to-be-joined portion 68A is formed to press the annular portion joint 75A of the main body portion 80 toward the inner peripheral direction (arrow d direction) in a state where the conductive elastic body portion 6A and the sealing device main body portion 7A are assembled. In addition, a dust-proof lip is not provided on the sealing main body 60 of the sealing device main body portion 7A.

[0108] In the sealing device 5A according to the fourth embodiment of the present invention, as Figure 13 shown, the base portion 62 of the sealing main body 60 of the sealing device main body portion 7A and the atmosphere-side lid portion 64a are received and engaged between the cylindrical portion joint 74 and the cylindrical portion engaging portion 76 of the conductive elastic body portion 6A and the annular portion joint 75A of the conductive elastic body portion 6A, so that the conductive elastic body portion 6A and the sealing device main body portion 7A are assembled with each other. In the sealing device 5A according to the fourth embodiment of the present invention, it also functions in the same manner as the above-described sealing device 5 and can obtain the same effect.

[0109] Next, the sealing device 5B according to the fifth embodiment of the present invention will be described. Hereinafter, structures having the same or similar functions as the conductive elastic body portions 6 and 6A and the sealing device main body portions 7 and 7A of the sealing devices 5 and 5A according to the above-described third and fourth embodiments are denoted by the same reference numerals and their descriptions are omitted, and different structures will be described.

[0110] Figure 14 is a partial perspective view of the sealing device 5B according to the fourth embodiment of the present invention. The sealing device 5B includes a conductive elastic body portion 6B and a sealing device main body portion 7B. As Figure 14 shown, the sealing device 5B is mainly different from the above-described sealing devices 5 and 5A in the structure of the main body portion of the conductive elastic body portion, the structure of the annular portion joint, and the structure of the annular portion to-be-joined portion. For example, as Figure 14 shown, the main body portion 80B of the conductive elastic body portion 6B is mounted on the surface 72c of the reinforcing ring 70 facing the sealing object side I. Specifically, for example, as Figure 14As shown, the connecting portion 83B of the main body portion 80B is installed on the inner peripheral side portion of the surface 72c of the reinforcing ring 70, and an annular space (space 69) is formed between the outer peripheral side end portion of the connecting portion 83B and the cylindrical portion 71 of the reinforcing ring 70. In addition, as Figure 14 shown, no base portion is provided on the main body portion 80B, and the conduction lip 81 extends from the inner peripheral side end portion of the connecting portion 83B.

[0111] In addition, as Figure 14 shown, an annular recess is formed on the inner peripheral side of the atmospheric side cover portion 64a of the sealing device main body portion 7B, and this recess is formed so as to be able to accommodate the connecting portion 83B of the main body portion 80B. The cylindrical portion of the gasket portion 63 protrudes toward the atmospheric side O at the portion below the engaging portion 63b, and a protruding portion 64b as an annular protruding portion is formed in the portion between the gasket portion 63 and the atmospheric side cover portion 64a. As Figure 14 shown, the protruding portion 64b is formed in a shape that can be accommodated in the annular space 69 between the outer peripheral side end (end 83b) of the connecting portion 83B of the conductive elastomer portion 6B and the cylindrical portion 71 of the reinforcing ring 70 in a state where the conductive elastomer portion 6B and the sealing device main body portion 7B are assembled. In addition, no dust-proof lip is provided on the sealing main body 60 of the sealing device main body portion 7B.

[0112] In addition, specifically, as Figure 14 shown, the circular ring portion engaging portion 75B is formed by the outer peripheral side end 83b facing the connecting portion 83B of the main body portion 80B of the conductive elastomer portion 6B, and the circular ring portion to-be-engaged portion 68B is formed by the inner peripheral side annular surface facing the annular protruding portion 64b of the sealing main body 60 of the sealing device main body portion 7B. That is, in a state where the conductive elastomer portion 6B and the sealing device main body portion 7B are assembled, the protruding portion 64b is accommodated in the space 69, and the outer peripheral side end 83b (circular ring portion engaging portion 75B) of the main body portion 80B facing the connecting portion 83B compresses the inner peripheral side surface (circular ring portion to-be-engaged portion 68B) of the protruding portion 64b in the radial direction between the cylindrical portion 71 of the reinforcing ring 70 of the conductive elastomer portion 6B. Thus, the circular ring portion engaging portion 75B becomes a form capable of engaging with the circular ring portion to-be-engaged portion 68B.

[0113] In the sealing device 5B according to the fifth embodiment of the present invention, as Figure 14 shown, the protruding portion 64b of the sealing main body 60 of the sealing device main body portion 7B is accommodated and engaged between the cylindrical portion engaging portion 74 and the cylindrical portion engaging portion 76 of the conductive elastomer portion 6B and the circular ring portion engaging portion 75B of the conductive elastomer portion 6B (space 69), so that the conductive elastomer portion 6B and the sealing device main body portion 7B are assembled with each other. In the sealing device 5B according to the fifth embodiment of the present invention, it also functions in the same manner as the above-described sealing device 5 and can obtain the same effects.

[0114] In addition, in the sealing device 5B, the material of the reinforcing ring 70 of the conductive elastomer portion 6B is a metal material. Further, the cylindrical portion 71 of the reinforcing ring 70 is in contact with the inner peripheral surface 103a of the through hole 103 of the housing 102 in the use state, as Figure 14 shown, the conductive circuit 8 is formed by the main body portion 80B and the metal reinforcing ring 70.

[0115] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the sealing devices 1, 4, 5, 5A, and 5B according to the above-described embodiments of the present invention, and also includes all modes included in the concept and claims of the present invention. In addition, the respective structures may be appropriately and selectively combined to achieve at least a part of the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each structure in the above-described embodiments may be appropriately changed according to the specific usage mode of the present invention.

[0116] Reference numerals:

[0117] 1, 4, 5, 5A, 5B... sealing devices, 2, 6, 6A, 6B... conductive elastomeric parts, 3, 8... conductive circuits, 7, 7A, 7B... sealing device main body parts, 10, 15, 50... reinforcing rings, 11, 51... cylindrical parts, 11a, 11c, 51a... end parts, 11b, 51b... outer peripheral surfaces, 12, 52... bending parts, 12a, 52a... end parts, 13, 16, 53... circular ring parts, 20, 25, 60... seal main bodies, 21, 61... sealing parts, 22, 62... bases, 23, 63... gasket parts, 63a... contact part, 63b... cylindrical part to-be-joined part, 63c... to-be-engaged part, 24, 64... cover parts, 64a... atmosphere-side cover part, 64b... protruding part, 66... dust-proof lip, 68, 68A, 68B... circular ring part to-be-joined parts, 69... space, 30... conducting lip, 31... conducting lip, 32... contact surface, 33... grease groove, 34... connection groove, 35... clamping spring, 36... grease supply part, 40, 65... sealing lips, 41, 48... sealing lips, 42... side surface of object to be sealed, 43... atmosphere side surface, 44... front end, 45... threaded groove, 46... threaded protrusion, 47, 67... clamping spring, 49... sealing surface, 70... reinforcing ring, 71... cylindrical part, 71a... end part, 71b... surface, 72... circular ring part, 72a, 72c... surfaces, 72b... end part, 73... sealing device joining part, 74... cylindrical part joining part, 75, 75A, 75B... circular ring part joining parts, 76... cylindrical part engaging part, 80, 80B... main body parts, 81... conducting lip, 81a... front end part, 82... base, 83, 83B... connecting parts, 83a... end part, 83b... end, 101... shaft, 101a... outer peripheral surface, 102... housing, 103... through hole, 103a... inner peripheral surface, 104... space, 200... impedance measuring device, 201... impedance analyzer, 202, 203... conductive components, I... sealed object side, G... grease, O... atmosphere side, S... space, x... axis.

Claims

1. A sealing device for sealing an annular space between an inner peripheral side member and an outer peripheral side member that rotate relative to each other, characterized in that, it includes: a conductive elastomer part, which is a member annularly surrounding an axis and has a part formed of an elastic material with conductivity, the conductive elastomer part can contact the inner peripheral side member and the outer peripheral side member, and can form a conductive circuit between the inner peripheral side member and the outer peripheral side member, in the relative rotation with a circumferential speed of 60 m / s or less, the impedance of the conductive circuit is 0.01 Ω or more and 100 Ω or less.

2. The sealing device according to claim 1, characterized in that, even if the conductive circuit is subjected to a force that eliminates the contact between the conductive elastomer part and the inner peripheral side member caused by the relative rotation, it still maintains electrical contact with the inner peripheral side member.

3. The sealing device according to claim 1, characterized in that, the conductive elastomer part has a heat resistance of -40° or more and 200° or less.

4. The sealing device according to claim 2, characterized in that, the conductive elastomer part has a conduction lip, the conduction lip is formed to be able to contact the inner peripheral side member and is annularly surrounding the axis, the sealing device further has a lubricant, the lubricant is interposed between the conduction lip and the inner peripheral side member and has conductivity.

5. The sealing device according to claim 4, characterized in that, the conduction lip has at least one groove for holding the lubricant, the groove is an annular groove surrounding the axis and is formed in a part of the conduction lip that contacts the inner peripheral side member.

6. The sealing device according to claim 2, characterized in that, it further includes: a sealing device main body part, which is a member annularly surrounding the axis for sealing the annular space, the conductive elastomer part can be installed on the sealing device main body part.

7. The sealing device according to claim 6, characterized in that, the conductive elastomer part has an annular reinforcing ring and a main body part formed of the conductive elastic material and installed on the reinforcing ring, the main body part has a conduction lip, the conduction lip is formed to be able to contact the inner peripheral side member and is annularly surrounding the axis, the conduction lip is provided on the inner peripheral side of a part on the inner peripheral side of the reinforcing ring.

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