Sealing device and bearing device

Abstract

Sealing devices 10A-10E each comprise: a connection part 20 that can be electrically connected to a first member 2; a lip part 40 that comes into contact with a target surface A on a second member 3 side; and a conductive core material part 30 that extends in the radial direction. The lip part 40 has a conductive axial lip 42 that includes a conductive material 43 that can come into contact with the target surface A while also comprising an elastic material 11. The conductive material is an annular body that has an outer diameter smaller than an outer diameter of the core material part 30 while also being flexible.

Description

Sealing device and bearing device

[0001] The present invention relates to a sealing device mounted between a first member and a second member that rotate relative to each other, and a bearing device including the sealing device.

[0002] Conventionally, there has been a problem that when an electric current flows through a bearing device having a first member and a second member, electrical erosion occurs on the surface of the rolling elements, leading to early failure of the bearing. In particular, since many electrical components are mounted in electric vehicles, there is a risk that a large amount of current will flow into the bearing device.

[0003] In order to solve this problem, a technique has been proposed in which a conductive material is disposed inside a sealing device mounted to seal the space between the first member and the second member, and the current that attempts to flow to the rolling elements is induced to the sealing device side (see, for example, Patent Document 1).

[0004] The device of Patent Document 1 is configured such that a conductive material exposed at the tip of an axial lip piece contacts the groove wall surface of a concave groove provided on the outer diameter surface of the inner ring (second member). This conductive material is disposed without interruption from the outer ring (first member) to the groove wall surface of the inner ring (second member) so as to generally follow the core wire of the core material portion disposed in the radial direction. In short, the first member and the second member are electrically conductive through the conductive material.

[0005] FIG. 2 of Japanese Unexamined Patent Application Publication No. 2009-264401

[0006] However, since the conductive material shown in Patent Document 1 is arranged as described above, as the conductive material, those having dimensions corresponding to the separation dimension between the first member and the second member (the interval dimension of the sealed space) are required. That is, as the conductive material, those having various dimensions such as large and small ones are required according to the shape of the bearing device, that is, mainly according to the dimensions of the sealing device and the core wire.

[0007] The present invention has been proposed in consideration of such circumstances, and its object is to reduce the amount of material used as the conductive material and to maintain an appropriate energization state when disposed between the first member and the second member, and to provide a sealing device and a bearing device.

[0008] To achieve the above objective, the configuration (1) of the sealing device of the present invention is a sealing device comprising an elastic material that, when mounted between a first member and a second member that rotate relative to each other, enables electrical connection between the first member and the second member, comprising: a connecting portion that is electrically connectable to the first member; a lip portion that contacts the target surface on the second member side; and a radially extending conductive core portion, wherein the lip portion comprises the elastic material and a conductive axial lip having a conductive material that can contact the target surface, and the conductive material is flexible and is an annular body whose outer diameter is smaller than the outer diameter of the core portion.

[0009] The bearing device of the present invention is characterized in that the sealing device is mounted between the outer ring, which is the first member, and the inner ring, which is the second member.

[0010] The following description of embodiments reveals that the sealing device according to the present invention may have the following dependent configurations.

[0011] <Configuration (2)> In configuration (1), the elastic material is conductive rubber and may be arranged continuously from the connecting portion to the conductive axial lip. <Configuration (3)> In configuration (1) or (2), the conductive material may be exposed at the inner diameter end of the conductive axial lip so that the end can contact the target surface. <Configuration (4)> In configuration (1) or (2), the conductive axial lip may have a bent portion that protrudes toward the target surface, the conductive material may be exposed on the surface of the bent portion toward the target surface, and the bent portion may be able to contact the target surface. <Configuration (5)> In any one of configurations (1) to (4), the target surface may be a surface that intersects the axial direction of the second member. <Configuration (6)> In any one of configurations (1) to (5), a groove is formed on the outer diameter surface of the second member along the circumferential direction, and the target surface is the groove wall surface of the groove. <Configuration (7)> ​​In any one of configurations (1) to (6), the target surface is the inner wall surface of the groove provided in the second member, and the conductive material is a plate-shaped material, and the plate surface of the plate-shaped material is made to be able to contact the inner wall surface along it.

[0012] Furthermore, the following description of embodiments reveals that the bearing device according to the present invention may include any one of the sealing devices described in configuration (1) to configuration (6).

[0013] Since the sealing device of the present invention has the configuration described above, the conductive material can be made an annular shape with a smaller diameter than the core material, thereby reducing the amount of material used as the conductive material compared to conventional methods, and at the same time, it is possible to maintain an appropriate current-conducting state when the sealing device is placed between the first member and the second member.

[0014] This is a schematic longitudinal cross-sectional view (common to all embodiments) of a bearing device equipped with a sealing device according to an embodiment of the present invention. (a) is a cut-off end view of the sealing device according to one embodiment, and (b) is a cut-off end view of the main part of the sealing device according to another embodiment. (a) and (b) are cut-off end views of the main part of the sealing device according to two other embodiments. These are cut-off end views of the sealing device according to yet another embodiment. (a) to (c) are cut-off end views of three examples of sealing devices according to yet another embodiment.

[0015] Several embodiments of the present invention will be described below with reference to the accompanying drawings.

[0016] First, the general configuration of the bearing device 1, to which the sealing devices 10A to 10F according to multiple embodiments are installed, will be described. The drawings relating to the various embodiments described below (see Figures 2 to 5) illustrate the sealing devices 10A to 10F in section X of Figure 1.

[0017] The bearing device 1 comprises a first member 2 and a second member 3 that rotate coaxially relative to the axis of the shaft 5. For example, the first member 2 is fitted into a housing (not shown), the shaft 5 is inserted through the second member 3, and the second member 3 rotates together with the shaft 5, thereby establishing a relative rotation relationship between the first member 2 and the second member 3. In other words, the first member 2 is configured as the outer ring of the bearing, and the second member 3 is configured as the inner ring of the bearing.

[0018] In this bearing device 1, sealing devices 10A to 10F are installed to seal the sealed space 6 between the first member 2 and the second member 3 from both ends in the axial direction L, thereby forming a sealed space. A single row of rolling elements 7 (balls in the illustrated example) are arranged in the sealed space 6, held in a retainer (not shown).

[0019] Various embodiments of the sealing devices 10A to 10F of the present invention can be described below. First, the common basic configuration of these sealing devices 10A to 10F will be described (see Figures 2 to 5). In the following descriptions of each figure, the inside of the bearing device 1 in the axial direction L of the sealing device 10, that is, the side of the sealed space 6 described later, is referred to as the inside of the axial direction L, and the opposite side of the axial direction L is referred to as the outside of the axial direction L.

[0020] The sealing devices 10A to 10F include an elastic material 11 that, when mounted between a first member 2 and a second member 3 that rotate relative to each other, enables electrical connection between the first member 2 and the second member 3. The sealing devices 10A to 10F include a connecting portion 20 that is electrically connectable to the first member 2, a lip portion 40 that contacts the target surface A on the second member 3 side, and a conductive core portion 30 that extends in the radial direction D. The lip portion 40 includes the elastic material 11 and a conductive axial lip piece 42 having a conductive material 43 that is capable of contacting the target surface A. The conductive material 43 is flexible and is an annular body whose outer diameter is smaller than the outer diameter of the core portion 30.

[0021] Here, the target surface A that the conductive axial lip piece 42 can contact includes surfaces that intersect the axial direction L of the second member 3, such as surfaces that are perpendicular to the axial direction L of the second member 3.

[0022] Next, we will describe the sealing devices 10A to 10D according to the four embodiments shown in Figures 2 and 3. First, we will describe the sealing device 10A according to the first embodiment with reference to Figure 2(a).

[0023] The sealing device 10A is fitted (internally fitted) to the first member 2, and the lip portion 40 is in sliding contact with the target surface A on the second member 3 side. In other words, the lip portion 40 is a part that prevents water and other foreign matter from entering the sealed space 6 by sliding contact with the second member 3 due to the relative rotation of the first member 2 and the second member 3.

[0024] A groove 2a is provided on the inner diameter side surface of the first member 2, and the connecting portion 20 of the sealing device 10A is fitted into this groove 2a. The second member 3 is provided with a stepped portion 3a, which consists of a first surface 3aa, which is a radial surface, and a second surface 3ab, which is an axial surface, and a conductive axial lip piece 42, which is a lip piece of the lip portion 40, slides against the second surface 3ab. The second surface 3ab is a surface that extends along the radial direction D and intersects with the axial direction L of the second member 3.

[0025] The sealing device 10A comprises a core metal 31, an elastic material 11, and a conductive material 43 as integral components. Figure 2(a) is a cross-sectional end view of the sealing device 10A, corresponding to section X in Figure 1. First, each part of the sealing device 10A will be described with reference to Figure 2(a).

[0026] The core metal 31 is the main material constituting the core material portion 30 of the sealing device 10A. It has higher rigidity than the elastic material 11, can serve as the core material of the sealing device 10A, and is made of a conductive metallic material. The core metal 31 comprises a core metal cylindrical portion 31a and a core metal disc portion 31b extending inward from its outer lateral end portion 31aa in the axial direction L.

[0027] In this embodiment, the connection portion 20 for electrically connecting to the first member 2 is formed including an elastic material 11. The elastic material 11 is continuously arranged without interruption over substantially the entire length in the radial direction D from the connection portion 20 through the outer surface in the axial direction L of the core material portion 30 to the lip portion 40.

[0028] The connecting portion 20 has a protruding portion 21 made of a part of the elastic material 11 that is fitted into the groove portion 2a formed in the first member 2. In the core material portion 30, the elastic material 11 is fixed to the outside in the axial direction L up to the inner end 31ba of the core metal disc portion 31b.

[0029] The lip portion 40 is composed of a lip base end portion 41 made of an elastic material 11, positioned near the inner end portion 31ba of the core metal disc portion 31b, and a conductive axial lip piece 42 extending from the lip base end portion 41 toward the sealed space 6 on the inner diameter side and in the axial direction L. The conductive axial lip piece 42 is formed in an inclined straight line shape when viewed in cross-section along the radial direction D.

[0030] The conductive axial lip piece 42 is composed of an elastic material 11 and a conductive material 43. The conductive material 43 is fixed to the surface of the conductive axial lip piece 42 on the sealed space 6 side in the axial direction L. The conductive material 43 has an outer diameter smaller than the outer diameter of the core material portion 30, and in this sealing device 10A, it is an annular body with an outer diameter approximately the same as the inner diameter of the core material portion 30.

[0031] The elastic material 11, which is one of the components of the sealing device 10A, is made of conductive rubber in which conductive carbon fillers are mixed with rubber material. Examples of conductive carbon fillers include carbon black, carbon fibers, carbon nanofibers, and graphite.

[0032] Furthermore, the conductive material 43 can be made from conductive materials such as copper, tungsten, or stainless steel, or conductive fibers such as carbon fiber. It is desirable to use a material that has at least higher conductivity (lower resistivity) than ordinary rubber.

[0033] Furthermore, the conductive material 43 is flexible and is composed of a flexible metal mesh-like plate material made by weaving together fine metal wires.

[0034] The conductive material 43 and the elastic material 11 become one integrated unit when the raw materials (not shown) of the elastic material 11 are impregnated into the metal mesh material or become entangled with metal wires such as metal fibers during the molding of the sealing device 10A. The conductive material 43 may also be a flexible perforated metal, in which case it is desirable that the elastic material 11 is inserted into the through-holes.

[0035] Since the conductive axial lip piece 42 is formed from the elastic material 11 and the conductive material 43, it is more easily deformed than the core material portion 30 including the core metal 31. The conductive material 43 is thinner than the conductive axial lip piece 42.

[0036] Furthermore, since the elastic material 11 is conductive, as long as the elastic material 11 is intertwined with or impregnated by the conductive material 43 and connected to it, electrical conductivity is possible from the protruding portion 21 of the connection portion 20 to the inner diameter end of the lip portion 40. For this reason, a core material made of a hard synthetic resin may be used instead of the core metal 31.

[0037] When this sealing device 10A is installed in the sealed space 6 between the first member 2 and the second member 3, the core metal cylindrical portion 31a on the first member 2 side is fitted into the first member 2 via the protruding portion 21 of the connecting portion 20, and the protruding portion 21 is compressed and inserted into the groove portion 2a.

[0038] On the other hand, on the second member 3 side, the conductive axial lip piece 42 is in elastic contact with the second surface 3ab of the stepped portion 3a. During the rotational operation of the bearing device 1, at least the conductive axial lip piece 42 is elastically deformed and maintains a sliding contact state with the second member 3.

[0039] At least the tip portion 42a (the inner diameter end) of the inclined conductive axial lip piece 42, and the conductive material 43 is exposed on the second surface 3ab side. The exposed surface 43a of the tip portion 42a of the conductive axial lip piece 42 contacts the second surface 3ab of the second member 3, which is the axial surface, along the entire circumference of the second member 3, regardless of whether the bearing device 1 is rotating or stopped, but does not contact the first surface 3aa of the second member 3.

[0040] In other words, the conductive material 43 contacts the second surface 3ab of the second member 3 along its entire circumference, and the conductive axial lip piece 42 becomes electrically conductive with the second member 3. Since the conductive axial lip piece 42 is a lip that contacts the second surface 3ab of the second member 3, which is an axial surface, it is less susceptible to dimensional fluctuations in the radial direction D, such as eccentricity of the second member 3, and fluctuations in the contact state of the conductive axial lip piece 42 can be suppressed.

[0041] Note that the conductive material 43 is not limited to being exposed only at the tip portion 42a. As in the example of FIG. 2(a), it is desirable for the conductive material to be exposed over substantially the entire length of the inner side surface in the axial direction L of the axial lip piece 42 for conduction in terms of stabilizing the conductive sliding contact.

[0042] As can be understood from the above description and FIG. 2(a), the axial lip piece 42 for conduction extends from the connecting portion 20 through a core material portion 30 including the core metal 31 and the elastic material 11 having conductivity and a lip base end portion 41 including the elastic material 11. Since the connecting portion 20 formed of the elastic material 11 annularly contacts the first member 2 and the exposed surface 43a of the axial lip piece 42 for conduction annularly contacts the second member 3, the sealing device 10A is in a conductive state between the first member 2 and the second member 3 regardless of whether the bearing device 1 is rotating or stopped.

[0043] In particular, if the conductive material 43 of the axial lip piece 42 for conduction is fixed to the elastic material 11 and the exposed surface 43a of the conductive material 43 contacts the second member 3 over a large area, the conductivity of the entire sealing device 10A can be increased.

[0044] Also, as described above, the lip portion 40 is provided with a lip base end portion 41 mainly composed of the elastic material 11 without including the conductive material 43. Thus, since the lip base end portion 41 is formed to be easily elastically deformed, during relative rotation, the axial lip piece 42 for conduction slidably contacts the second member 3 while the lip base end portion 41 elastically and finely deforms.

[0045] Thus, even when the bearing device 1 is relatively rotating, the axial lip piece 42 for conduction slidably contacts the second member 3 stably, so that interruption of energization is suppressed.

[0046] Also, due to the flexibility of the lip base end portion 41 of the axial lip piece 42 for conduction, the reaction force due to contact with the second member 3 is suppressed. Therefore, heat generation due to the sliding contact of the axial lip piece 42 for conduction can be suppressed, the progress of deterioration of the axial lip piece 42 for conduction can be suppressed, and an increase in rotational torque can also be avoided.

[0047] In addition, even when a punching metal with low flexibility is adopted as the conductive material 43 of the axial lip piece 42 for conduction, if the lip base end portion 41 has sufficient flexibility, the reaction force of the axial lip piece 42 for conduction can be reduced.

[0048] Also, depending on the hardness (degree of flexibility) of the conductive material 43, the flexibility of the entire axial lip piece 42 for conduction may be impaired. However, by making the conductive material 43 thinner or increasing the internal space capacity of the conductive material 43, the flexibility of the entire axial lip piece 42 for conduction can be enhanced.

[0049] Further, since the sealing device 10A of the present embodiment is configured such that the lip base end portion 41 of the lip portion 40 does not include the conductive material 43, the entire lip portion 40 is easily elastically deformed. Therefore, the lip portion 40 is ensured swingability by the certain elasticity of the elastic material 11, and a relatively large movable range is secured.

[0050] Since the sealing device 10A has the above configuration, when the sealing device 10A is mounted between the first member 2 and the second member 3, the conductivity between the first member 2 and the second member 3 is ensured. Also, since the connecting portion 20 has conductivity due to the elastic material 11, the outer diameter of the conductive material 43 may be made smaller than the outer diameter of the core member portion 30 in order to ensure the conductivity between the first member 2 and the second member 3. By doing so, the conductive material 43 can be made smaller and the amount of material used as the conductive material 43 can be reduced.

[0051] In the present embodiment, since the outer diameter of the conductive material 43 is approximately the same as the inner diameter of the core member portion 30 (core metal 31), the amount of material used as the conductive material 43 can be further reduced. Note that as the conductive material 43, a material with a relatively large outer diameter may be arranged along the radial direction D of the core metal disk portion 31b up to the vicinity of the core metal cylindrical portion 31a.

[0052] Next, the sealing devices 10B, 10C, and 10D according to the other second to fourth embodiments will be described while referring to FIGS. 2(b) and FIGS. 3(a) and (b).

[0053] As shown in Figures 2(b) and 3(a)(b), in these embodiments, a groove 3c is formed on the outer diameter surface of the second member 3 along the circumferential direction. A portion of the conductive axial lip piece 42 of the lip portion 40 of the sealing devices 10B, 10C, and 10D mounted on the bearing device 1 is placed within this groove 3c.

[0054] The groove portion 3c has an outer groove wall surface 3ca located on the outside in the axial direction L, an inner groove wall surface 3cb located on the inside in the axial direction L, and a groove bottom surface 3cc. Both the outer groove wall surface 3ca and the inner groove wall surface 3cb are axial surfaces, and one of them is the target surface A that the lip portion 40 contacts. A flange portion 3d is formed on the outside of the groove portion 3c in the axial direction L, and the outer diameter of the flange portion 3d (i.e., the outer diameter of the outer groove wall surface 3ca) is smaller than the outer diameter of the inner groove wall surface 3cb.

[0055] In the following, the same configuration as that of the sealing device 10A according to the first embodiment will not be described. The sealing devices 10B, 10C, and 10D according to the second to fourth embodiments shown in Figures 2(b) and 3(a)(b) are equivalent to the sealing device 10A according to the first embodiment in that they use an elastic material 11, a core metal 31, and a conductive material 43 as materials.

[0056] Furthermore, the fitting shape of the first member 2 (shape of the groove 2a) is the same as that of the first embodiment. Also, the fitting structure between the sealing devices 10B, 10C, and 10D and the first member 2 is the same as that of the first embodiment.

[0057] Therefore, for the sealing devices 10B, 10C, and 10D according to the second to fourth embodiments shown in Figures 2(b) and 3(a)(b), the descriptions of the common components will be omitted below, and only the configuration and shape of the lip portion 40, the positional relationship between the lip portion 40 and the core material portion 30, and the positional relationship between the lip portion 40 and the second member 3 will be described.

[0058] Furthermore, regarding the sealing device 10E according to the fifth embodiment (see Figure 4), which is another embodiment, there are differences in the configuration of the connection part 20 and the core material part 30 compared to the sealing device 10A according to the first embodiment, so the overall configuration will be described later in the explanation of Figure 4.

[0059] First, the main parts of the sealing device 10B according to the second embodiment shown in Figure 2(b) will be described.

[0060] The lip portion 40 is composed of a lip base end portion 41 made of an elastic material 11, which is positioned on the sealed space 6 side in the axial direction L of the inner end portion 31ba of the core metal disc portion 31b, and a conductive axial lip piece 42 that extends downward in a stepped shape in a cross-sectional view along the radial direction D toward the inner diameter from the lip base end portion 41.

[0061] The conductive axial lip piece 42 is composed of an elastic material 11 and a conductive material 43. The conductive material 43 is fixed to the surface of the conductive axial lip piece 42 on the sealed space 6 side in the axial direction L, and its outer diameter is smaller than the outer diameter of the core material portion 30. In particular, in this sealing device 10B, it is an annular body with dimensions approximately the same as the inner diameter of the core material portion 30.

[0062] Furthermore, the conductive axial lip piece 42 has a bent portion 42b that protrudes toward the inner groove wall surface 3cb, which is designated as the target surface A, when the sealing device 10B is mounted on the bearing device 1. The conductive material 43 is exposed at the V-shaped corner portion 42c on the surface of the bent portion 42b facing the target surface A, and the portion of the exposed surface 43a corresponding to the corner portion 42c is curved. The exposed surface 43a is such that at least the curved portion can contact the inner groove wall surface 3cb.

[0063] The conductive material 43 includes a first portion 43c provided at a location corresponding to the lip base end 41 so as to extend along the radial direction D, and a second portion 43d provided at a location corresponding to the lip middle portion 45 so as to extend toward the sealed space 6 while decreasing in diameter. The conductive axial lip piece 42 has an inner diameter surface 42e formed at the bent portion 42b that is inclined to move away from the sealed space 6 and to decrease in diameter. The conductive axial lip piece 42 has an outer diameter surface formed at the second portion 43d that approaches the sealed space 6 and decreases in diameter.

[0064] Since the sealing device 10B has the configuration and shape described above, it achieves the same effects as the sealing device 10A of the first embodiment.

[0065] Furthermore, since the conductive axial lip piece 42 of the sealing device 10B has a V-shaped bent portion 42b, and in combination with the fact that the flange portion 3d of the second member 3 is set back on the inner diameter side, when the sealing device 10B is installed in the recessed groove portion 3c, the inner diameter surface 42e of the conductive axial lip piece 42 (bent portion 42b) can act as a guide surface, making installation easier.

[0066] Furthermore, because the bent portion 42b is V-shaped, wear particles from sliding contact can be easily retained in the V-shaped groove (the back side of the outer corner portion 42c) partitioned by the bent portion 42b, thereby suppressing the outflow of wear particles to the outside of the bearing device 1.

[0067] Next, the main parts of the sealing device 10C according to the third embodiment shown in Figure 3(a) will be described.

[0068] The lip portion 40 is composed of a lip base end portion 41 made of an elastic material 11, which is positioned on the sealed space 6 side in the axial direction L of the inner end portion 31ba of the core metal disc portion 31b, and a conductive axial lip piece 42 that extends parallel to the core metal 31 in a cross-sectional view along the radial direction D toward the inner diameter from the lip base end portion 41.

[0069] The conductive axial lip piece 42 is composed of an elastic material 11 and a conductive material 43. The conductive material 43 is fixed to the surface of the conductive axial lip piece 42 on the sealed space 6 side in the axial direction L, and its outer diameter is smaller than the outer diameter of the core material portion 30. In this sealing device 10C, it is an annular body with dimensions approximately the same as the inner diameter of the core material portion 30.

[0070] Furthermore, the conductive axial lip piece 42 is configured such that when the sealing device 10C is mounted on the bearing device 1, the exposed surface 43a of the conductive material 43 at the tip portion 42a contacts the inclined inner groove wall surface 3cb, which is designated as the target surface A. The inner groove wall surface 3cb is an inclined surface that decreases in diameter as it moves from the side of the sealed space 6 toward the opposite side.

[0071] Since the sealing device 10C has the configuration and shape described above, it achieves the same effects as the sealing device 10A of the first embodiment.

[0072] Furthermore, compared to the first embodiment, the sealing device 10C has the conductive material 43 positioned further away from the core metal 31 in the axial direction L. As a result, the lip base end 41 can be formed thinner than the conductive axial lip piece 42, as shown in the figure example. Consequently, the flexibility of the lip portion 40 can be increased, meaning that the amount of oscillation of the conductive axial lip piece 42 can be increased. Therefore, smooth sliding contact of the conductive axial lip piece 42 with the target surface A can be achieved.

[0073] Furthermore, since the shape of the lip portion 40, and especially the shape of the conductive material 43, is flat, the sealing device 10C does not require the disc-shaped conductive material 43 to be deformed into a frustoconical shape during the molding stage using a mold (not shown), thereby reducing the effort required during molding.

[0074] Furthermore, the dashed lines within the lip portion 40 in Figure 3(a) represent cylindrical recesses 42d, of which multiple recesses are formed along the circumferential direction. These recesses 42d are indentations formed by protrusions (not shown; for example, part of the mold) used to firmly fix the conductive material 43 inside the mold during the molding stage using a mold (not shown).

[0075] By providing multiple such recesses 42d along the circumferential direction on the elastic material 11 portion of the conductive axial lip piece 42, the conductive axial lip piece 42 becomes more flexible, enabling smoother sliding contact with the target surface A.

[0076] Next, the main parts of the sealing device 10D according to the fourth embodiment shown in Figure 3(b) will be described.

[0077] The lip portion 40 is composed of a lip base end portion 41 made of an elastic material 11, which is positioned on the sealed space 6 side in the axial direction L of the inner end portion 31ba of the core metal disc portion 31b, and a conductive axial lip piece 42 which is positioned in a substantially triangular shape in cross-section from the lip base end portion 41 toward the inner diameter.

[0078] The conductive axial lip piece 42 is composed of an elastic material 11 and a conductive material 43. When the sealing device 10D is mounted on the bearing device 1, the surface corresponding to one side of the roughly triangular conductive axial lip piece 42 faces the groove bottom surface 3cc and the inner groove wall surface 3cb of the recessed groove 3c, and the conductive material 43 is fixed to that surface in an inclined manner (the conductive material 43 as a whole is frustoconical in shape), with a protruding portion 43b, which is the inner diameter end of the conductive material 43, extending so as to contact the outer groove wall surface 3ca.

[0079] Since the sealing device 10D has the configuration and shape described above, it achieves the same effects as the sealing device 10A of the first embodiment.

[0080] Furthermore, since the sealing device 10D has the above-described configuration and shape, instead of arranging the conductive axial lip piece 42 so that the inner diameter side projection 43b of the conductive material 43 contacts the outer groove wall surface 3ca, or in addition to arranging it so that the outer diameter side portion of the conductive material 43 contacts the inner groove wall surface 3cb, the conductive axial lip piece 42 can also be arranged so that the outer diameter side portion of the conductive material 43 contacts the inner groove wall surface 3cb.

[0081] Furthermore, in this sealing device 10D, the conductive axial lip piece 42 has an inner diameter surface 42e that narrows in diameter so as to move away from the sealed space 6 side. Combined with the fact that the flange portion 3d of the second member 3 is set back on the inner diameter side, the inner diameter surface 42e acts as a guide surface when the lip portion 40 of the sealing device 10 is fitted into the groove portion 3c, making fitting easier.

[0082] In all of the sealing devices 10A to 10D according to the embodiments described above, the lip portion 40 has only one conductive axial lip piece 42, and the conductive axial lip piece 42 is configured to slide against the axial surface (target surface A) in the axial direction.

[0083] In short, such a lip portion 40 should not be positioned on the extension of the inner diameter side of the core material portion 30, but rather at a position shifted from the core material portion 30 toward the sealed space 6 in the axial direction L of the second member 3 (see Figures 2 and 3).

[0084] Therefore, when attaching the sealing devices 10A to 10D to the bearing device 1, insertion of the lip portion 40 into the groove portion 3c is significantly easier compared to those having radial lip pieces. Furthermore, as mentioned above, attachment becomes even easier if the lip portion 40 has an inner diameter surface 42e (see Figures 2(b) and 3(b)).

[0085] Next, the sealing device 10E according to the fifth embodiment shown in Figure 4 will be described. Note that this figure, like Figure 2(a), is a cross-sectional end view of the sealing device 10E between the first member 2 and the second member 3.

[0086] In this embodiment, the second member 3 is equivalent to that of the second embodiment in that it has a groove 3c on its outer diameter surface. The sealing device 10E is equivalent to the sealing device 10B of the second embodiment in that it consists of an elastic material 11, a core metal 31, and a conductive material 43. Therefore, a detailed explanation of these materials will be omitted.

[0087] In this embodiment, no groove 2a (see Figure 2(a)) is formed on the inner diameter side surface of the first member 2, and the sealing device 10E is configured such that the core metal cylindrical portion 31a is fitted into the first member 2 via the elastic material 11.

[0088] The connecting portion 20 is composed of an elastic material 11 fixed to the outer diameter side of the core metal cylindrical portion 31a. The core material portion 30 is composed of a core metal 31 and an elastic material 11 fixed to the inside of the core metal 31 in the axial direction L.

[0089] The lip portion 40 is composed of a lip base end portion 41 made of an elastic material 11, which is positioned on the inner diameter side of the inner end portion 31ba of the core metal disc portion 31b; a conductive axial lip piece 42 extending inward from the lip base end portion 41; and another lip piece 44 extending from the lip base end portion 41 toward the sealed space 6 in the axial direction L further than the conductive axial lip piece 42.

[0090] The conductive axial lip piece 42 is composed of an elastic material 11 and a conductive material 43. The conductive axial lip piece 42 has a bent portion 42b that protrudes toward the outer groove wall surface 3ca, which is the target surface A, when the sealing device 10E is mounted on the bearing device 1, and the conductive material 43 is exposed in a part of the bent portion 42b, including the outer corner portion 42c.

[0091] Since the sealing device 10E has the configuration and shape described above, it achieves the same effects as the sealing device 10A of the first embodiment.

[0092] Furthermore, as shown in the illustration of this embodiment, the conductive material 43 may not extend to the inner diameter tip 42a of the conductive axial lip piece 42, but may be positioned in a part of the bent portion 42b (the outer corner 42c and its vicinity). This will further reduce the amount of conductive material 43 required.

[0093] Furthermore, because the bent portion 42b is V-shaped, wear particles from sliding contact can be easily retained in the V-shaped groove (the back side of the outer corner portion 42c) partitioned by the bent portion 42b, thereby suppressing the outflow of wear particles to the outside of the bearing device 1. In addition, since the lip portion 40 is also equipped with other lip pieces 44, wear particles can be retained between the conductive axial lip piece 42 and the other lip pieces 44, further suppressing the outflow of wear particles to the outside of the bearing device 1.

[0094] The other lip pieces 44 are axial lip pieces arranged so as not to contact the inner groove wall surface 3cb. Thus, the lip portion 40 may have multiple axial lip pieces, and at least one of them may be a conductive axial lip piece 42.

[0095] Next, three examples of the sealing device 10F according to the sixth embodiment shown in Figures 5(a) to 5(c) will be described. Note that all three of these figures, like Figure 2(a), are cross-sectional end views of the sealing device 10F between the first member 2 and the second member 3.

[0096] In this embodiment, the sealing device 10E is equivalent to the sealing device 10B of the second embodiment in that it comprises an elastic material 11, a core metal 31, and a conductive material 43 as materials.

[0097] In this embodiment, a groove 2a similar to that shown in Figure 2(a) is formed on the inner diameter side surface of the first member 2, recessed in the radial direction D, while a recessed groove 3e is formed on the outer diameter side of the second member 3, recessed in the axial direction L. This recessed groove 3e also opens on the outer diameter side. In other words, the height of the groove wall 3ed from the groove bottom surface 3ec on the outer diameter side of the recessed groove 3e is smaller than the height of the groove wall 3ee on the inner diameter side.

[0098] The inner wall surface (inner diameter surface) 3ea of ​​the outer diameter side groove wall 3ed of the recessed groove portion 3e is a tapered surface that narrows toward the groove bottom surface 3ec, and the inner wall surface (outer diameter surface) 3eb on the inner diameter side is a cylindrical surface.

[0099] The sealing device 10F is configured to have a connecting portion 20 in which the core metal cylindrical portion 31a is fitted to the first member 2 via an elastic material 11. The connecting portion 20 is made up of an elastic material 11 fixed to the outer diameter side of the core metal cylindrical portion 31a. The core material portion 30 is made up of a core metal 31 and an elastic material 11 fixed to the outer side in the axial direction L of the core metal disc portion 31b of the core metal 31.

[0100] The lip portion 40 is composed of a lip base end portion 41 made of an elastic material 11, which is positioned on the inner diameter side of the inner end portion 31ba of the core metal disc portion 31b; a conductive axial lip piece 42 extending inward from the lip base end portion 41; and another lip piece 44 positioned outward in the axial direction L from the lip base end portion 41 than the conductive axial lip piece 42.

[0101] The conductive axial lip piece 42 is composed of an elastic material 11 and a conductive material 43. The exposed surface 43a (outer diameter surface) of the conductive axial lip piece 42 on the conductive material 43 side is a tapered surface with approximately the same inclination angle as the inner wall surface (inner diameter surface) 3ea of ​​the groove wall 3ed on the outer diameter side of the recessed groove 3e.

[0102] In other words, when the sealing device 10F is mounted on the bearing device 1, the conductive axial lip piece 42 is positioned such that the exposed surface 43a of the conductive material 43 is in surface contact (surface sliding contact) with the inner wall surface (inner diameter surface) 3ea which is designated as the target surface A.

[0103] In the three examples of sealing devices 10F shown in Figures 5(a) to 5(c), the arrangement of the conductive material 43 differs. However, the conductive material 43 is flexible and has an annular shape with an outer diameter smaller than the outer diameter of the core material portion 30, as is the case with the sealing devices 10A to 10E described above.

[0104] In the configuration shown in Figure 5(a), the conductive material 43 is arranged to continuously follow the inner surface of the core metal disc portion 31b in the axial direction L and the inner surface of the elastic material 11 in the lip portion 40 in the axial direction L.

[0105] In the configuration shown in Figure 5(b), the conductive material 43 is sandwiched between the core metal 31 and the elastic material 11 on the outer surface of the core metal disc portion 31b in the axial direction L, and the conductive material 43 is arranged along the inner surface of the elastic material 11 in the lip portion 40 in the axial direction L, continuous with the elastic material 11 on the core material portion 30 side. Neither the conductive material 43 nor the elastic material 11 is fixed to the end face of the inner end portion 31ba of the core metal disc portion 31b.

[0106] In the configuration shown in Figure 5(c), the conductive material 43 is sandwiched between the core metal 31 and the elastic material 11 on the outer surface of the core metal disc portion 31b in the axial direction L, and also runs along the end face of the inner end portion 31ba of the core metal disc portion 31b. Furthermore, the conductive material 43 is arranged to run along the inner surface of the elastic material 11 in the lip portion 40 in the axial direction L, and is continuous with the elastic material 11 on the core material portion 30 side.

[0107] With these sealing devices 10F, the contact area is increased because the plate surface of the conductive material 43 is aligned with the inner wall surface (inner diameter surface) 3ea of ​​the groove portion 3e, thereby increasing the amount of current that can be conducted and slowing down the wear of the conductive material 43. Furthermore, wear particles and conductive grease from the conductive material 43 can be accumulated in the groove portion 3e. In addition, compared to pressing the inner diameter side end surface of the conductive material 43 against the second member 3, torque can be reduced and the generation of wear particles can be reduced.

[0108] Furthermore, since all of these sealing devices 10F have the configuration and shape described above, they achieve the same effects as the sealing device 10A of the first embodiment. In addition, the sealing devices 10F shown in Figures 5(a), 5(b), and 5(c) each have the following effects.

[0109] According to the sealing device 10F in Figure 5(a), the radial dimension D of the conductive material 43 can be reduced compared to those in Figures 5(b) and 5(c). Furthermore, according to the sealing device 10F in Figures 5(b) and 5(c), since the conductive material 43 is sandwiched and fixed between the core metal disc portion 31b and the elastic material 11, separation and peeling of the conductive material 43 from the sealing device 10F can be suppressed.

[0110] Furthermore, the sealing device 10F shown in Figure 5(b) allows for a smaller axial thickness L of the lip base end 41 compared to the sealing devices 10F shown in Figures 5(a) and 5(c). Therefore, even if the conductive material 43 is positioned outside the axial direction L of the core metal 31, it can extend towards the conductive axial lip piece 42 while gently curving from the outside of the axial direction L, thereby reducing the load on the conductive material 43 during the operation of the bearing device 1, similar to the sealing device 10F shown in Figure 5(a).

[0111] Furthermore, in the sealing device 10F of Figure 5(c), the lip base end 41 is arranged in the same way as the sealing device 10F of Figure 5(a), with the elastic material 11 covering the inner end 31ba of the core metal disc portion 31b. This allows the conductive material 43 to be sandwiched between the inner end 31ba and the lip base end 41, thereby further stabilizing the conductive material 43.

[0112] The sealing devices 10A to 10F described above are merely examples, and various other forms are also acceptable, as described below.

[0113] The conductive axial lip piece 42 is in contact with axial surfaces (target surface A) extending in the radial direction D, such as the second surface 3ab (see Figure 2(a)), the outer groove wall surface 3ca (see Figure 2(b)), and the inner groove wall surface 3cb. However, it may also be configured to come into contact with radial surfaces (first surface 3aa) (see Figure 2(a)) or groove bottom surface 3cc (see Figure 2(b)) extending in the axial direction L, as the range of motion expands due to the rotational operation of the bearing device 1.

[0114] Thus, by employing an axial lip such as the conductive axial lip piece 42 as the conductive lip, the contact area in the second member 3 is likely to increase, thereby suppressing instability in the contact state of the conductive lip due to dimensional fluctuations in the radial direction D, such as eccentricity of the second member 3.

[0115] In the sealing devices 10A to 10F, the conductive material 43 is made of a plate-like material, but it may also be made of a thin film, a thin plate, or other flat material. Furthermore, the conductive material 43 does not have to be a metal mesh made by weaving together metal fine wires, but may also be a nonwoven fabric made by intertwining or bonding conductive fibers. More specifically, the conductive material 43 may be made of carbon fiber paper made by forming carbon-based short fibers with a resin binder. The conductive material 43 may also be made of various materials having at least voids or through holes.

[0116] Furthermore, the conductive material 43 is not limited to being in contact with the target surface A over its entire circumference, but may be configured to be in partial contact with the target surface A. In other words, in the sealing devices 10A to 10F, recesses may be provided at predetermined intervals in the circumferential direction in a portion of the conductive material 43 that was in contact with the second member 3, and the portion protruding from the recess may be configured to contact the target surface A of the second member 3 in the circumferential direction.

[0117] The conductive material 43 is not limited to an annular shape whose outer diameter is approximately the same as the inner diameter of the core material 30, but may be an annular shape whose outer diameter is smaller than the outer diameter of the core material 30 as described above, and may even be an annular shape whose outer diameter is sufficiently smaller than the inner diameter of the core material 30. As an example of a sufficiently small outer diameter, the conductive material 43 may be an annular shape with dimensions of about 1 / 3 or less of the radial dimension D of the conductive axial lip piece 42, and may be placed at the tip portion 42a of the conductive axial lip piece 42.

[0118] Furthermore, the lip base portion 41 may be made solely of the elastic material 11, and the outer diameter of the conductive material 43 may be reduced to make the lip base portion 41 larger and longer in the radial direction D. With this configuration, the lip portion 40 becomes more elastically deformable, and it goes without saying that the range of motion of the conductive axial lip piece 42 is increased.

[0119] The elastic material 11 is not necessarily limited to being made of conductive rubber, but may also be made of non-conductive rubber. In this case, for example, a part of the outer diameter side of the core material portion 30 (for example, the core metal cylindrical portion 31a) can be directly fitted to the first member 2 as a connecting portion 20 to electrically connect it to the first member 2.

[0120] Furthermore, it goes without saying that the overall shape of the sealing devices 10A to 10F can be appropriately changed to shapes other than those shown in the figures, for example, depending on the shape of the bearing device 1 to which it is mounted.

[0121] Furthermore, the sealing devices 10A to 10F according to the present invention are not limited to those applied to the bearing device 1, but may also be applied to, for example, an oil seal installed between a housing and a rotating shaft. Moreover, they are not limited to bearing seals or oil seals, but may be seals for other applications as long as they seal the space between a first member 2 and a second member 3 that rotate relative to each other.

[0122] 1 Bearing device 2 First member (outer ring) 2a Groove 3 Second member (inner ring) A Target surface 3a Stepped portion 3aa First surface 3ab Second surface 3c Recessed groove 3ca Outer groove wall surface 3cb Inner groove wall surface 3cc Groove bottom surface 3d Flange 3e Recessed groove 3ea Inner wall surface (inner diameter surface) 3eb Inner wall surface (outer diameter surface) 3ec Groove bottom surface 3ed, 3ee Groove wall 6 Sealed space 10A to 10F Sealing device 11 Elastic material 20 Connecting portion 21 Protruding portion 30 Core material portion 31 Core metal 40 Lip portion 41 Lip base end 42 Conductive axial lip piece (conductive axial lip) 42a Tip portion (inner diameter side end) 42b Bent part 43 Conductive material 43a Exposed surface

Claims

1. A sealing device comprising an elastic material that, when mounted between a first member and a second member that rotate relative to each other, enables electrical connection between the first member and the second member, comprising: a connecting portion that is electrically connectable to the first member; a lip portion that contacts the target surface on the second member side; and a radially extending conductive core portion, wherein the lip portion comprises the elastic material and a conductive axial lip having a conductive material that can contact the target surface, and the conductive material is flexible and is an annular body whose outer diameter is smaller than the outer diameter of the core portion.

2. The sealing device according to claim 1, characterized in that the elastic material is conductive rubber and is continuously arranged from the connecting portion to the conductive axial lip.

3. The sealing device according to claim 1, characterized in that the conductive material is exposed at the inner diameter end of the conductive axial lip, and the end is capable of contacting the target surface.

4. The sealing device according to claim 1, wherein the conductive axial lip has a bent portion that is bent so as to protrude toward the target surface, the conductive material is exposed on the surface of the bent portion facing the target surface, and the bent portion is capable of contacting the target surface.

5. The sealing device according to claim 1, characterized in that the target surface is a surface that intersects the second member in the axial direction.

6. The sealing device according to claim 1, characterized in that a groove is formed on the outer diameter surface of the second member along the circumferential direction, and the target surface is the groove wall surface of the groove.

7. The sealing device according to claim 1, wherein the target surface is the inner wall surface of a groove provided in the second member, and the conductive material is a plate-shaped material, and the plate surface of the plate-shaped material is capable of contacting the inner wall surface along it.

8. A bearing device characterized in that any of the sealing devices according to claims 1 to 7 is mounted between the outer ring as the first member and the inner ring as the second member.

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