Sealing device, bearing device, and manufacturing method of sealing device

Abstract

To provide a sealing device which can improve so as to increase an electric current amount in the sealing device disposed between a first member and a second member, and to provide a manufacturing method of the sealing device.SOLUTION: In a sealing device 10A to 10D, an annular sealing device, attached to a space to be sealed between a first member 2 and a second member 3 which rotate relative to each other and is formed containing an elastic material, includes an elastic part 41 which contacts with or moves close to the first member 2 and is mainly formed by an elastic material 40; a lip part 50 which contacts with or moves close to a second member 3 side object surface and is mainly formed by the elastic material 40; and a conductive base material 30 which may assist electric connection between the first member 2 and the second member 3. A first extending piece 35 formed by a part of the conductive base material 30 protrudes from the lip part 50 so as to contact with the second member 3 side object surface.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sealing device mounted in a sealed space between a first member and a second member that rotate relative to each other, a bearing device in which the sealing device is mounted, and a method for manufacturing the sealing device.

Background Art

[0002] Conventionally, there has been a problem that when an electric current flows through a bearing device in which a plurality of rolling elements are arranged between a first member and a second member, electrical erosion occurs on the surface of the rolling elements, leading to an 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, as a constituent material of a sealing device mounted on a bearing device to seal the sealed space between the first member and the second member, a conductive material such as a conductive carbon filler is added to induce the current flowing toward the rolling elements to the sealing device side. For example, in Patent Document 1, a fibrous conductive material is arranged in the sealing device along the radial direction, and the conductive material is exposed at each of the outer diameter side end portion and the inner diameter side end portion of the sealing device. And in Patent Document 1, a technique is proposed in which each exposed portion is brought into contact with the first member and the second member to make the space between the first member and the second member conductive.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technology of Patent Document 1, on the first member side, the conductive material only exposes as a part of the end face of the elastic part. On the other hand, on the second member side, the conductive material only exposes as a part of the end face (tip face) of the lip part. Therefore, it is not always certain that these exposed parts will surely contact the counterpart member. In particular, since the lip part is in a relationship of relative rotation with the second member, there is a possibility that the contact of the exposed part of the conductive material with respect to the second member becomes unstable during repeated rotation.

[0006] Also, as a means for preventing the occurrence of electrical erosion on the surface of the rolling element, a method has been proposed in which conductive grease is disposed on the surface of the rolling element so as not to retain electricity in the rolling element. However, this method has problems such as the high cost of the conductive grease and the inability to maintain conductivity over a long period, and thus cannot be said to be an effective measure.

[0007] Furthermore, conventionally, rubber having conductivity has been proposed for the elastic material used in the sealing device. However, when a carbon filler is added to impart conductivity to the elastic material, there is a concern that the elasticity may be impaired if the ratio of the carbon filler contained in the rubber material is too large. Therefore, there is a limit to the addition ratio of the carbon filler, and there is a limit to the improvement of the conductivity of the sealing device by using rubber having conductivity.

[0008] The present invention has been proposed in consideration of such circumstances, and its object is to provide a sealing device capable of increasing the amount of electricity conducted in a sealing device disposed between a first member and a second member, a bearing device to which the sealing device is attached, and a method for manufacturing the sealing device.

Means for Solving the Problems

[0009] In order to achieve the above object, the sealing device of the present invention is an annular sealing device formed including an elastic material, which is mounted in a sealed space between a first member and a second member that rotate relative to each other. The sealing device includes an elastic portion made of the elastic material that contacts or is close to the first member, a lip portion made of the elastic material that contacts or is close to a target surface on the second member side, and a conductive base material that enables auxiliary electrical connection between the first member and the second member. A first extension piece formed of a part of the conductive base material protrudes so as to contact the target surface on the second member side from the lip portion.

[0010] The manufacturing method of the sealing device of the present invention is a manufacturing method of a sealing device, which molds the sealing device of the present invention using a mold composed of an upper mold and a lower mold. In the manufacturing method, the first extension piece is made to protrude from among raw materials of the elastic material, the raw materials of the elastic material and the conductive base material are arranged in the mold, and a molding preparation step of sandwiching the first extension piece between the upper mold and the lower mold at one side of the mold end portion on the outer diameter side and the inner diameter side of the mold is provided.

Advantages of the Invention

[0011] Since the present invention has the above-described configuration or procedure, an increase in the amount of electricity conducted in the sealing device arranged between the first member and the second member can be expected.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, based on FIG. 1, the schematic basic configuration of the bearing device 1 equipped with the sealing devices 10A to 10D will be described. Note that the drawings related to various embodiments described below (see FIGS. 2 to 5) illustrate the sealing devices 10A to 10D in the X portion in FIG. 1.

[0014] The bearing device 1 includes a first member 2 (outer member) and a second member 3 (inner member) that rotate coaxially relative to each other around the axis L 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. That is, the first member 2 is configured as the outer ring of the bearing, and the second member is configured as the inner ring of the bearing. The first member 2 may be the rotating side and the second member 3 may be the fixed side.

[0015] The sealing devices 10A to 10D are mounted so as to seal the sealed space 6 between the first member 2 and the second member 3 in the bearing device 1 from both ends in the axial direction of the axis L, thereby forming a sealed space. In the sealed space 6, a single row of rolling elements 7 (balls in the illustrated example) are held between the first member 2 and the second member 3 while being held by a retainer (not shown).

[0016] As the sealing devices 10A to 10D of the present invention, those of various embodiments are listed as described below. First, the common schematic basic configuration of these sealing devices 10A to 10D and the outline of the manufacturing method thereof will be described with reference to FIGS. 2 to 5.

[0017] The sealing devices 10A to 10D include an elastic part 41 mainly made of an elastic material 40 that contacts or is close to the first member 2, a lip part 50 mainly made of the elastic material 40 that contacts or is close to the target surface on the second member 3 side, and a conductive base material 30 that enables auxiliary electrical connection between the first member 2 and the second member 3. A first extension piece 35 formed of a part of the conductive base material 30 protrudes so as to contact the target surface on the second member 3 side from the lip part 50.

[0018] In addition, in any of the sealing devices 10A to 10D described below, the elastic material 40, which is a constituent member of the sealing devices 10A to 10D, is formed of a conductive rubber in which a conductive carbon filler or the like is mixed in a rubber material. Examples of the conductive carbon filler include carbon black, carbon fiber, graphite, and the like.

[0019] In any of these sealing devices 10A to 10D, a core material 20, which is another constituent member, is fitted (internally fitted) to the first member 2. On the second member 3 side, the lip part 50 is in a sliding contact relationship with the target surface on the second member 3 side (the first surface 3b or the second surface 3c of the second member 3 (see FIGS. 2, 3, and 4), or the outer surface 61c of the slinger 60 of the sealing device 10D interposed between the second member 3 (see FIG. 5)). Note that for the sealing device 10D, the slinger 60 is in a fitting (externally fitted) relationship with the second member 3.

[0020] In this way, the lip part 50 is a part for suppressing the intrusion of water and other foreign substances into the sealed space 6 by minimizing the gap between the first member 2 and the second member 3 due to relative rotation. The lip part 50 is formed mainly of the elastic material 40 and secondarily of the conductive base material 30.

[0021] Moreover, the manufacturing method of these sealing devices 10A to 10D is a manufacturing method of molding using a molding die 70 composed of a first mold 71 and a second mold 72. With the first extending piece 35 protruding from the raw material of the elastic material 40, the raw material of the elastic material 40 and the conductive base material 30 are arranged in the molding die 70, and the first extending piece 35 is sandwiched between the mold end portions 71a and 71b of the first mold 71 and the mold end portions 72a and 72b of the second mold 72 at one end on the outer diameter side and the inner diameter side of the molding die 70. Here, the first mold 71 is the upper mold, and the second mold is the lower mold.

[0022] Next, regarding the details of the sealing devices 10A to 10D shown in FIGS. 2 to 5 respectively, the common matters, as well as the detailed configurations and manufacturing methods for each drawing, will be described with reference to the drawings.

[0023] First, the common matters of the sealing devices 10A to 10D according to the four embodiments will be described. The sealing devices 10A to 10D include an elastic portion 41 made of an elastic material 40 that contacts the first member 2, a lip portion 50 made of an elastic material 40 that contacts or is close to the target surface on the second member 3 side, a conductive base material 30, and a core material 20 for fitting into the first member 2.

[0024] The conductive base material 30 is easily deformable (has flexibility) and is preferably composed of a metal mesh material formed by weaving fine metal wires, but it may also be a plate-shaped metal material having through holes such as flexible punching metal. Further, the conductive base material 30 is an annular body thinner than the core material 20. If the conductive base material 30 is composed of a metal mesh material, it can be formed more flexibly, and the conductive base material 30 can be brought into contact and sliding contact with the target surfaces of the first member 2 and the second member 3 in a bent state, facilitating the design of the sealing devices 10A to 10D. Also, if the conductive base material 30 is sufficiently flexible, it is easy to arrange in the mold 70 during the molding of the sealing devices 10A to 10D, which is convenient.

[0025] The core material 20 is an annular body having higher rigidity than the conductive base material 30, and is preferably made of a metallic material having conductivity. However, the core material 20 only needs to have such rigidity that it can be used as the framework of the sealing devices 10A to 10D, and may be made of, for example, a hard synthetic resin material as long as it has higher rigidity than at least the conductive base material 30. Although the sealing devices 10A to 10D are formed including the conductive base material 30 to ensure conductivity, it goes without saying that in order to further enhance conductivity, the core material 20 is preferably made of a metallic material having conductivity.

[0026] The three materials of the core material 20, the conductive base material 30, and the elastic material 49 constituting the sealing devices 10A to 10D may be superposed and fixed in this order in the axial direction of the axis L, and the core material 20 may be arranged on either the outer side or the inner side in the axial direction of the axis L. The lip portion 50 only needs to contact or be close to the target surface on the side of the second member 3. In the illustrated examples described below, the number of lip pieces constituting the lip portion 50 is set to 1 to 3.

[0027] When manufacturing the sealing devices 10A to 10D using the mold 70, in the molding preparation step, the raw materials (molten materials) of the core material 20, the conductive base material 30, and the elastic material 40 are arranged in the cavity of the mold 70.

[0028] After executing this molding preparation step, the raw material of the elastic material 40 is compressed by the mold 70, and a part of the raw material of the elastic material 40 enters the voids and through holes of the conductive base material 30 and reaches the surface of the core material 20 through them. Then, the elastic material 40 is fixed via the adhesive applied to the core material 20. Thereby, the core material 20, the conductive base material 30, and the elastic material 40 are fixed and integrated. When the conductive base material 30 is constituted by a metal mesh material, the entire conductive base material 30 is impregnated with the elastic material 40.

[0029] Next, the sealing devices 10A to 10D in FIGS. 2 to 5 will be individually described. First, the sealing device 10A in FIG. 2 will be described. FIG. 2(a) is a view showing the state in which the sealing device 10A is mounted on the bearing device 1, and FIG. 2(b) is a view of the state before the sealing device 10A is mounted, and is a view schematically showing the manufacturing process of the sealing device 10A.

[0030] A groove portion 2b is formed on the fitting surface 2a of the first member 2. A stepped portion 3a is formed on the second member 3, and the stepped portion 3a has a first surface 3b along the axial direction of the shaft L and a second surface 3c along the radial direction.

[0031] This sealing device 10A includes a core material 20, an elastic portion 41 that contacts the first member 2, a lip portion 50 that contacts or is close to the second member 3, and a conductive base material 30. The core material 20 includes a cylindrical portion 21 extending in the axial direction of the shaft L and a disk portion 22 extending from the first end portion 21b on the outer side in the axial direction of the shaft L toward the inner diameter side in the radial direction, and is formed in a substantially L-shaped cross section.

[0032] The conductive base material 30 is fixed to the inner diameter surface in the radial direction of the cylindrical portion 21 and from the outer diameter side to the inner diameter side on the inner surface in the axial direction of the disk portion 22 (the entire inner surface of the disk portion 22). The total length of the conductive base material 30 is longer than the sum of the dimension of the inner diameter surface of the cylindrical portion 21 in the axial direction of the shaft L and the dimension of the inner surface of the disk portion 22 in the radial direction. And an elastic material 40 is fixed to the inner side in the axial direction of the conductive base material 30. That is, the conductive base material 30 is sandwiched between the core material 20 and the elastic material 40.

[0033] Also, the elastic portion 41 formed by the elastic material 40 is fixed to the core material 20 so as to extend radially outward until it wraps (covers) the open end portion 21a of the cylindrical portion 21. The inner end portion 22a of the disk portion 22 is the inner end portion in the radial direction, and the elastic material 40 is fixed to both surfaces in the axial direction of the inner end portion 22a. The sealing device 10A is formed with a lip portion 50 having one first lip 51 made of the elastic material 40 and extending obliquely on the inner diameter side in the radial direction and on the inner side in the axial direction of the shaft L.

[0034] The conductive base material 30 is fixed to substantially the entire first side surface 20a of the core material 20 and extends in a substantially straight line in a cross-sectional view toward the inner diameter side in the radial direction. That is, the conductive base material 30 extends so as to protrude further toward the inner diameter side from the inclined end surface 50a on the inner diameter side in the radial direction of the first lip 51, and a first extension piece 35 formed of a part of the conductive base material 30 is formed. Further, on the outer diameter side, the conductive base material 30 extends to the second end portion 21a of the inner diameter surface of the cylindrical portion 21, and the end portion on the outer diameter side thereof is not exposed to the outside.

[0035] As described above, the conductive base material 30 is disposed so as to contact the second end portion 21a of the cylindrical portion 21 and the inner end portion 22a of the disk portion 22, and is arranged to be sandwiched between the core material 20 and the elastic material 40. And in the conductive base material 30, a first extension piece 35 protrudes toward the inner diameter side in the radial direction.

[0036] When the sealing device 10A is fitted between the first member 2 and the second member 3 and mounted, on the first member 2 side, the elastic portion 41 is fitted into the groove portion 2b of the first member 2, and on the second member 3 side, the first lip 51 contacts the second surface 3c of the second member 3, and the first extension piece 35 contacts the first surface 3b of the second member 3.

[0037] In this state (see Fig. 2(a)), the first extension piece 35 contacts the first surface 3b in a state of being bent so as to face the side opposite to the first lip 51 (compare Fig. 2(a) and (b)). Note that the lip portion 50 itself (main body) is not in contact with the second member 3, and the distance between the first surface 3b of the second member 3 is larger than the distance between the first lip 51 and the second surface 3c of the second member 3.

[0038] In this way, the elastic material 40 having conductivity contacts the first member 2, and the first extension piece 35 which is a part of the conductive base material 30 contacts the second member 3. Therefore, the sealing device 10A can be 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.

[0039] In this way, even when the tip of the lip portion 50 (the portion excluding the first extension piece 35) of the sealing device 10A is not in contact with the second member 3, the contact of the first extension piece 35 with the second member 3 side can ensure the conductivity between the first member 2 and the second member 3.

[0040] In manufacturing this sealing device 10A, as shown in Fig. 2(b), a mold 70 as a molding die composed of an upper die 71 as a first mold and a lower die 72 as a second mold is used.

[0041] Specifically, a molding preparation step is executed when molding with the mold 70. This molding preparation step is carried out in the following procedure. With the first extension piece 35 of the conductive base material 30 protruding from the raw material of the elastic material 40, the conductive base material 30 is placed adjacent to the first side surface 20a of the core material 20. In this way, the core material 20, the conductive base material 30, and the raw material of the elastic material 40 are arranged in the mold 70, and the protruding first extension piece 35 is sandwiched between the mold end portion 71a of the upper die 71 and the mold end portion 72a of the lower die 72 at the inner diameter side end of the mold 70.

[0042] In this way, when manufacturing this sealing device 10A, it is only necessary to arrange the conductive base material 30 between the core material 20 and the raw material of the elastic material 40 in the mold 70. In that case, the inner diameter side end of the conductive base material 30 may be arranged so as to be sandwiched between the mold end portions 71a and 72a of the upper and lower molds 70 on the inner diameter side of the mold 70 and to protrude radially inward from the cavity of the mold 70. And after executing this molding preparation step, a step of compressing the raw material of the elastic material 40 may be executed. In the step of compressing the raw material of the elastic material 40, the raw material of the elastic material 40 spreads over the entire conductive base material 30, and the elastic material 40 is impregnated and fixed to the entire conductive base material 30.

[0043] By arranging the conductive base material 30 in the mold 70 in this way, the first extension piece 35 can be made to protrude from the end face 50a such as the corner portion 50b of the lip portion 50, which is a portion corresponding to the split position of the upper die 71 and the lower die 72.

[0044] Further, according to this molding preparation step, since the first extension piece 35 of the conductive base material 30 is fixed by being sandwiched between the mold end portion 71a of the upper mold 71 and the mold end portion 72a of the lower mold 72, the positioning of the conductive base material 30 in the mold 70 becomes easy. Therefore, it is possible to prevent the displacement of the conductive base material 30 in the mold 70 before molding.

[0045] In short, if one end in the radial direction of the conductive base material 30 is fixed by the mold 70, the substantially flat plate-shaped conductive base material 30 can be maintained in a curved, bent and deformed state (curved in a cross-sectional view) in the mold 70. As a result, the conductive base material 30 can be arranged at an appropriate position and state that matches the shape of the sealing device 10A. In addition, in order to complement the maintenance of the shape of the conductive base material 30 in the mold 70, the conductive base material 30 and the core material 20 may be fixed with an adhesive.

[0046] Next, the sealing device 10B in FIG. 3 will be described. FIG. 3(a) is a diagram showing a state where the sealing device 10B is mounted on the bearing device 1, FIG. 3(b) is a diagram showing a state before the sealing device 10B is mounted, and is a diagram schematically showing the manufacturing process of the sealing device 10B.

[0047] The first member 2 and the second member 3 to which the sealing device 10B is to be mounted are the same as those in FIG. 2 as shown in FIG. 3(a).

[0048] This sealing device 10B includes a core material 20, an elastic portion 41 that contacts the first member 2, a lip portion 50 that contacts or is close to the second member 3, and a conductive base material 30. The core material 20 includes a cylindrical portion 21 extending in the axial direction of the shaft L and a disk portion 22 extending from the first end portion 21b on the outer side in the axial direction of the shaft L to the inner diameter side in the radial direction, and is formed in a substantially L-shaped cross section.

[0049] The sealing device 10B has a conductive base material 30 fixed to the outer diameter surface in the radial direction of the cylindrical portion 21 and from the outer diameter side to the inner diameter side on the outer surface in the axial direction L of the disk portion 22 (the entire outer surface of the disk portion 22). An elastic material 40 is fixed to the outer side of the conductive base material 30 in the axial direction L. That is, the conductive base material 30 is sandwiched between the core material 20 and the elastic material 40.

[0050] Further, an elastic portion 41 formed by the elastic material 40 is fixed to the outer diameter side in the radial direction of the cylindrical portion 21. At the inner end portion 22a of the disk portion 22, the elastic material 40 is fixed to both surfaces in the axial direction L thereof. In the sealing device 10B, the elastic material 40 extends to the inner diameter side in the radial direction, and a lip portion 50 composed of first, second, and third lips 51, 52, and 53 is formed. The first lip 51 extends to the inner diameter side and the outer side in the axial direction. The third lip 53 extends to the inner side in the axial direction L and is close to the second surface 3c of the second member 3. The second lip 52 is close to the first surface 3b of the second member 3.

[0051] The conductive base material 30 is fixed to the entire first side surface 20a of the core material 20 and extends in a bent shape in a cross-sectional view toward the inner diameter side in the radial direction. Then, the conductive base material 30 extends so as to protrude from the end surface 50a on the inner diameter side of the second lip 52, and a first extension piece 35 formed of a part of the conductive base material 30 is formed.

[0052] Also, the conductive base material 30 extends along the outer surface of the first end portion 21b of the core material 20 toward the outer diameter side in the radial direction, passes through the elastic portion 41, and extends so as to protrude from the end surface 41a of the elastic portion 41, and a second extension piece 36 formed of a part of the conductive base material 30 is formed.

[0053] As described above, the conductive base material 30 is arranged so as to contact the first end portion 21b of the cylindrical portion 21 and the inner end portion 22a of the disk portion 22, and to be sandwiched between the core material 20 and the elastic material 40. In this way, the conductive base material 30 includes a first extension piece 35 protruding from the inner diameter side in the radial direction and a second extension piece 36 protruding from the outer diameter side.

[0054] When the sealing device 10B is fitted between the first member 2 and the second member 3 and mounted, on the side of the first member 2, the elastic portion 41 is fitted into the groove portion 2b of the first member 2 and the second extension piece 36 contacts the first member 2. On the side of the second member 3, the second lip 52 is close to or contacts the first surface 3b of the second member 3, and the first extension piece 35 contacts the first surface 3b of the second member 3.

[0055] In this state (see Fig. 3(a)), the elastic portion 41 is elastically deformed and the second extension piece 36 contacts the first member 2 in a deflected state, and the first extension piece 35 also contacts the first surface 3b of the second member 3 in a deflected state (compare Figs. 3(a) and 3(b)). Note that the lip portion 50 itself (the main body) is not in contact with the second member 3.

[0056] In this way, the second extension piece 36 which is a part of the conductive base material 30 contacts the first member 2, and the first extension piece 35 which is a part of the conductive base material 30 contacts the second member 3. Therefore, the sealing device 10B can be 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.

[0057] In this way, even if the tip of the lip portion 50 (the portion excluding the first extension piece 35) is not in contact with the second member 3, the conductivity between the first member 2 and the second member 3 can be ensured by the contact of the first extension piece 35 with the second member 3 side.

[0058] For manufacturing this sealing device 10B, as shown in Fig. 3(b), a mold 70 composed of an upper mold 71 and a lower mold 72 is used.

[0059] Specifically, a molding preparation step is executed when molding with the mold 70. This molding preparation step is carried out in the following procedure. The first extension piece 35 and the second extension piece 36 of the conductive base material 30 are made to protrude from the raw material of the elastic material 40, and the conductive base material 30 is placed adjacent to the first side surface 22b of the core material 20. Thus, the raw materials of the conductive base material 30 and the elastic material 40 are arranged in the mold 70, and the protruding first extending piece 35 is sandwiched between the mold end portion 71a of the upper mold 71 and the mold end portion 72a of the lower mold 72 at the inner diameter side end of the mold 70, and the protruding second extending piece 36 is sandwiched between the mold end portion 71b of the upper mold 71 and the mold end portion 72b of the lower mold 72 at the outer diameter side end of the mold 70.

[0060] In this way, when manufacturing this sealing device 10B, the core material 20 and the raw material of the elastic material 40 are arranged in the mold 70, and the conductive base material 30 is arranged between them. In that case, the inner diameter side end of the conductive base material 30 may be arranged so as to be sandwiched between the mold end portions 71a and 72a of the upper and lower molds 70 at the inner diameter side end of the mold 70 and protrude to the inner diameter side in the radial direction. Furthermore, the outer diameter side end of the conductive base material 30 may be arranged so as to be sandwiched between the mold end portions 71b and 72b of the upper and lower molds 70 at the outer diameter side end of the mold 70 and protrude to the outer diameter side in the radial direction. And after executing this molding preparation step, a step of compressing the raw material of the elastic material 40 may be executed.

[0061] By arranging the conductive base material 30 in the mold 70 in this way, the first extending piece 35 can be made to protrude from the end face 50a such as the corner portion 50b of the second lip 52 which is a portion corresponding to the parting position of the upper mold 71 and the lower mold 72. Also, the second extending piece 36 can be made to protrude from the end face 41a such as the corner portion 41b of the elastic portion 41 which is a portion corresponding to the parting position of the upper mold 71 and the lower mold 72.

[0062] Also, according to this molding preparation step, since the first extending piece 35 and the second extending piece 36 of the conductive base material 30 are fixed by being sandwiched between the mold end portions 71a and 71b of the upper mold 71 and the mold end portions 72a and 72b of the lower mold 72, the positioning of the conductive base material 30 in the mold 70 becomes easy. Therefore, it is possible to prevent the displacement of the arrangement of the conductive base material 30 in the mold 70 before molding.

[0063] In other words, if both end portions in the radial direction of the conductive base material 30 are fixed by the mold 70, the substantially flat conductive base material 30 can be maintained in a curved and bent deformed state (curved shape in cross-sectional view) within the mold 70. As a result, the conductive base material 30 can be disposed at an appropriate position and in an appropriate state that matches the shape of the sealing device 10B.

[0064] Next, the sealing device 10C in FIG. 4 will be described. FIG. 4(a) is a view showing a state where the sealing device 10C is attached to the bearing device 1, and FIG. 4(b) is a view of the state before the sealing device 10C is attached and is a view schematically showing the manufacturing process of the sealing device 10C.

[0065] The fitting surface 2a of the first member 2 to which the sealing device 10C is to be attached is a cylindrical inner peripheral surface without unevenness. Also, the other member 3 to which it is to be attached is the same as that in FIG. 2 as shown in FIG. 4(a).

[0066] This sealing device 10C includes a core material 20, an elastic portion 41 that contacts the first member 2, a lip portion 50 that contacts or is close to the second member 3, and a conductive base material 30. The core material 20 includes a cylindrical portion 21 that fits into the inner peripheral surface of the first member 2, and a disk portion 22 that extends from the first end portion 21b on the outer side in the axial direction L thereof toward the inner diameter side in the radial direction, and is formed in a substantially L-shaped cross section.

[0067] In the sealing device 10C, the conductive base material 30 is fixed from the outer diameter surface in the radial direction of the cylindrical portion 21 and from the outer diameter side to the inner diameter side of the outer surface on the outer side in the axial direction L of the disk portion 22. An elastic material 40 is fixed to the outer side in the axial direction L of the conductive base material 30. That is, the conductive base material 30 is sandwiched between the core material 20 and the elastic material 40.

[0068] Also, on the outer diameter side in the radial direction of the cylindrical portion 21, an elastic portion 41 made of an elastic material 40 is fixed so as to be adjacent to the outer side in the axial direction L of the cylindrical portion 21. Note that a part of the end face 41a of the elastic portion 41 bulges for fitting assistance (see FIGS. 4(a) and 4(b)).

[0069] Further, on the inner radial end portion 22 of the disk portion 22, elastic members 40 are fixed to both surfaces in the radial direction thereof, and the elastic members 40 extend toward the inner diameter side in the radial direction, and a lip portion 50 including first, second, and third lips 51, 52, and 53 is formed.

[0070] The conductive base material 30 is fixed to the entire surface of the first side surface 20a of the core material 20 and extends in a bent shape in a cross-sectional view toward the inner diameter side in the radial direction. Then, the conductive base material 30 extends so as to protrude from the end surface 50a on the inner diameter side of the second lip 52, and a first extension piece 35 formed of a part of the conductive base material 30 is formed.

[0071] Also, the conductive base material 30 extends along the space between the core material 20 and the elastic portion 41 toward the outer diameter side in the radial direction so as to protrude from the end surface 41a of the elastic portion 41, and a second extension piece 36 formed of a part of the conductive base material 30 is formed.

[0072] As described above, the conductive base material 30 is arranged so as to contact the first end portion 21b of the cylindrical portion 21 and the inner end portion 22a of the disk portion 22 and to be sandwiched between the core material 20 and the elastic material 40. Thus, the sealing device 10C includes a first extension piece 35 protruding from the inner diameter side in the radial direction and a second extension piece 36 protruding from the outer diameter side.

[0073] When the sealing device 10C is fitted and mounted between the first member 2 and the second member 3, on the first member 2 side, the cylindrical portion 21 is fitted to the first member 2, and the elastic portion 41 having the protruding strip portion 41c complements the fitting by the cylindrical portion 21. The shapes of the lip portion 50 and the second extension piece 36 of the sealing device 10C on the second member side are substantially the same as those of the sealing device 10B in FIG. 3, and the shape of the second member 3 with which the lip portion 50 contacts is also the same. Therefore, the description of the contact mode thereof is omitted.

[0074] Also, since the conduction action and effect between the first member 2 and the second member 3 by the conductive base material 30 are substantially the same as those of the sealing device 10B in FIG. 3, the description thereof is omitted.

[0075] In the manufacture of this sealing device 10C, as shown in Fig. 4(b), a mold 70 composed of an upper mold 71 and a lower mold 72 is used.

[0076] Specifically, when molding with the mold 70, a molding preparation step is executed. This molding preparation step is carried out according to the following procedure. With the first extension piece 35 and the second extension piece 36 of the conductive base material 30 protruding from the raw material of the elastic material 40, the conductive base material 30 is placed adjacent to the first side surface 22b of the core material 20. In this way, the conductive base material 30 and the raw material of the elastic material 40 are arranged in the mold 70, and the protruding first extension piece 35 is sandwiched between the mold end 71a of the upper mold 71 and the mold end 72a of the lower mold 72 at the inner diameter side end of the mold 70, and the protruding second extension piece 36 is sandwiched between the mold end 71b of the upper mold 71 and the mold end 72b of the lower mold 72 at the outer diameter side end of the mold 70.

[0077] Since this molding preparation step is the same as that of the sealing device shown in Fig. 3(b), the details and the effects of the molding preparation step will be omitted here.

[0078] In the manufacturing method of this sealing device 10, after molding the sealing device 10C with the mold 70, in order to adjust the lengths of the tip portions of the first extension piece 35 and the second extension piece 36 in the molded product, the first extension piece 35 and the second extension piece 36 are cut off (see the comparison of Figs. 4(a) and (b)).

[0079] Next, the sealing device 10D in Fig. 5 will be described. Fig. 5(a) is a diagram showing the state in which the sealing device 10D is mounted on the bearing device 1, Fig. 5(b) is a diagram showing the state before the sealing device 10D is mounted, and is also a diagram schematically showing the manufacturing process of the sealing device 10D.

[0080] The fitting surface 2a of the first member 2 to which the sealing device 10D is to be mounted is a cylindrical inner peripheral surface without irregularities. The contact surface of the sealing device 10D with respect to the second member 3 is a cylindrical outer peripheral surface without irregularities.

[0081] This sealing device 10D is composed of two separated members, namely a core member part 20A with a core material 20 as the main material and a slinger 60, and these are integrated and mounted in the sealed space 6 of the bearing device 1.

[0082] The core member part 20A includes a core material 20, an elastic part 41 that contacts the first member 2, a lip part 50 that contacts or is close to the target surface (slinger 60) on the second member 3 side, and a conductive base material 30. The core material 20 includes a cylindrical part 21 that fits into the inner peripheral surface of the first member 2, and a disk part 22 that extends radially inward from the lateral end part 21b on the inner side in the axial L direction, and is formed in a substantially L-shaped cross-section view.

[0083] The conductive base material 30 is fixed from the radially inner diameter surface of the cylindrical part 21 and to the inner diameter side from the outer diameter side of the outer surface in the axial L direction of the disk part 22, and an elastic material 40 is fixed to the outer side in the axial L direction of the conductive base material 30. That is, the conductive base material 30 is in a state of being sandwiched between the core material 20 and the elastic material 40.

[0084] Also, the elastic part 41 formed by the elastic material 40 is fixed to extend radially outward so as to enclose the open end part 21a of the cylindrical part 21. The elastic material 40 is fixed to both sides in the axial L direction of the inner end part 22a of the disk part 22. Note that a protrusion part 41c is formed on the end face 41a of the elastic part 41 for fitting assistance (see FIGS. 5(a) and 5(b)).

[0085] The elastic material 40 is fixed to both sides of the radially inner end part 22a of the disk part 22, and the elastic material 40 extends radially inward, and a lip part 50 composed of two first and second lips 51 and 52 is formed.

[0086] The conductive base material 30 extends in a substantially straight line shape in a cross-section view toward the radially inner diameter side. And the conductive base material 30 extends so as to protrude from the end face 50a on the inner diameter side of the first lip 51, and a first extension piece 35 composed of a part of the conductive base material 30 is formed.

[0087] Further, the conductive base material 30 extends from the end face 41a of the elastic part 41 toward the outer diameter side along the first side face of the disk part 22 while passing through the cylindrical part 21 toward the outer diameter side in the radial direction, and a second extension piece 36 made of a part of the conductive base material 30 is formed.

[0088] As described above, the conductive base material 30 is disposed so as to be in contact with the lateral end part 21b of the cylindrical part 21, the inner corner part of the cylindrical part 21 and the disk part 22, and the inner end part 22a of the disk part 22, and is arranged so as to be sandwiched between the core material 20 and the elastic material 40. And in the sealing device 10D, the first extension piece 35 protrudes toward the inner diameter side in the radial direction, and the second extension piece 36 protrudes toward the outer diameter side in the radial direction.

[0089] On the other hand, the slinger 60 is made of a metal material and includes a first cylindrical part 61 located on the inner diameter side in the radial direction, a second cylindrical part 63 located on the outer diameter side in the radial direction, and a disk part 62 of the slinger that connects the outer side end parts in the axial L direction between the first cylindrical part 61 and the second cylindrical part 63. The first cylindrical part 61 is a part that fits (externally fits) into the second member 3.

[0090] In a state where the sealing device 10D is fitted and mounted between the first member 2 and the second member 3, on the first member 2 side, the cylindrical part 21 of the core material part 20A fits into the first member 2, and the elastic part 41 having the ridge part 41c complements the fitting by the cylindrical part 21. Further, the second extension piece 36 contacts the first member 2. On the second member 3 side, the first lip 51 is close to or contacts the outer peripheral surface of the first cylindrical part 61 of the slinger 60, and the first extension piece 35 contacts the outer peripheral surface 61a of the first cylindrical part 61.

[0091] In this state (see Fig. 5(a)), the second extension piece 36 protruding from the elastic part 41 contacts the corner part of the first member 2 in a bent state, and the first extension piece 35 contacts the outer peripheral surface of the first cylindrical part 61 in a bent state (compare Figs. 5(a) and (b)). In the illustrated example, the main body of the first lip 51 also contacts the outer peripheral surface 61a of the first cylindrical part 61.

[0092] Thus, a second extension piece 36, which is a part of the conductive base material 30, contacts the first member 2, and a first extension piece 35, which is a part of the conductive base material 30, is indirectly electrically contacted with the second member 3 via the slinger 60. Therefore, regardless of whether the bearing device 1 is in a rotating operation or a stopped state, the sealing device 10D can be in a conductive state between the first member 2 and the second member 3.

[0093] For manufacturing the core material portion 20A of this sealing device 10D, as shown in FIG. 5(b), a mold 70 including an upper mold 71 and a lower mold 72 is used.

[0094] Specifically, a forming preparation step is executed when forming with the mold 70. This forming preparation step is performed according to the following procedure. The first extension piece 35 and the second extension piece 36 of the conductive base material 30 are made to protrude from the raw material of the elastic material 40, and the conductive base material 30 is placed adjacent to the first side surface 20a of the core material 20. In this way, the conductive base material 30 and the raw material of the elastic material 40 are arranged in the mold 70, and the protruding first extension piece 35 is sandwiched between the mold end portion 71a of the upper mold 71 and the mold end portion 72a of the lower mold 72 at the inner diameter side end of the mold 70, and the protruding second extension piece 36 is sandwiched between the mold end portion 71b of the upper mold 71 and the mold end portion 72b of the lower mold 72 at the outer diameter side end of the mold 70.

[0095] Thus, when manufacturing the core material portion 20A of these sealing devices 10D, it is only necessary to arrange the core material 20 and the raw material of the elastic material 40 in the mold 70 and place the conductive base material 30 therebetween. In that case, the inner diameter side end of the conductive base material 30 may be arranged so as to be sandwiched between the mold end portion 71a of the upper mold 71 and the mold end portion 72a of the lower mold 72 at the inner diameter side end of the mold 70 and protrude beyond the inner diameter side in the radial direction. Furthermore, the outer diameter side end of the conductive base material 30 may be arranged so as to be sandwiched between the mold end portion 71b of the upper mold 71 and the mold end portion 72b of the lower mold 72 at the outer diameter side end of the mold 70 and protrude beyond the outer diameter side in the radial direction. And after executing this forming preparation step, a step of compressing the raw material of the elastic material 40 may be executed.

[0096] By disposing the conductive base material 30 in the mold 70 in this way, the first extension piece 35 can be made to protrude from the end face 50a such as the protruding corner part 50b of the first lip 51, which is the part corresponding to the parting position of the upper mold 71 and the lower mold 72, and the second extension piece 36 can be made to protrude from the end face 41a such as the protruding corner part 41b of the elastic part 41, which is the part corresponding to the parting position of the upper mold 71 and the lower mold 72.

[0097] Since this molding preparation step is substantially the same as that of the sealing device shown in Fig. 3(b), the description of other effects by the molding preparation step is omitted.

[0098] In the sealing devices 10B to 10D described above, the first extension piece 35 protrudes from the end face 50a of the lip part 50 corresponding to the facing surface with the target surface (such as the first surface 3b of the step part 3a) of the second member 3, but it may protrude from a non-facing surface such as the sealing device 10A shown in Fig. 2 or a surface facing the axial direction L. The same applies to the second extension piece 36. For example, if the elastic part 41 has a fitting structure that fits into the groove part 2b as in the sealing device 10B of Fig. 3, the second extension piece 36 does not have to be the facing surface with the first member 2.

[0099] As the sealing devices 10A to 10D (see Figs. 3 to 5) using the conductive base material 30, an example using a conductive rubber as the elastic material 40 has been described above. However, for the sealing devices 10B to 10D having the second extension piece 36, since the conductive base material 30 also contacts the first member 2, an elastic material 40 having no conductivity may be used.

[0100] Also, in the case of the sealing devices 10C and 10D (see Figs. 4 and 5) where the core material 20 directly contacts the first member 2, conductivity can be ensured by the core material 20 and the second extension piece 36 may not be provided. However, when an adhesive is interposed between the core material 20 and the first member 2, conductivity through the core material 20 may not be ensured. Therefore, it is desirable to provide the second extension piece 36.

[0101] Also, as the sealing devices 10A to 10D, an example where the elastic portion 41 contacts the first member 2 has been described, but the elastic portion 41 does not necessarily have to contact the first member 2. For example, the elastic portion 41 does not have to contact the first member 2 as long as it is close enough to the first member 2 that the second extension piece 36 can contact the first member 2. The conductive base material 30 does not have to be a plate-like metal material having through holes such as a metal mesh or a flexible punched metal. For example, the conductive base material 30 may be constituted by a single thin metal wire, and the metal wire may be configured to protrude from the end face of the lip portion 50. Also, a conductive resin film may be used as the conductive base material 30.

[0102] As the sealing devices 10A to 10D, the state in which the first extension piece 35 of the conductive base material 30 contacts the target surface on the second member 3 side is not necessarily limited to a form in a deflected state, and as long as electrical connection is ensured, it also includes a form in which the conductive base material 30 contacts in a non-deformed state.

[0103] As the sealing devices 10A to 10D, the arrangement and shape of the conductive base material 30 may be changed so that the first extension piece 35 protrudes not only from the end face of the lip portion 50 but also from other parts of the lip portion 50. As the sealing devices 10A to 10D, the arrangement and shape of the conductive base material 30 may be changed so that the second extension piece 36 protrudes not only from the end face 41a of the elastic portion 41 but also from other parts of the elastic portion 41.

[0104] The end face 50a of the lip portion 50 does not necessarily have to be formed so as to face the target surface of the second member 3 (for example, the first surface 3b of the step portion 3a, etc.). Even if the end face 50a of the lip portion 50 does not face the target surface of the second member 3, it is sufficient that the conductive base material 30 contacts the target surface of the second member 3.

[0105] As the sealing devices 10A to 10C, an example where the first lip 51 is non-contact has been described, but the first lip 51 may be in contact. Also, as the sealing devices 10A to 10C, an example where the lip portion 50 is non-contact has been described, but the lip portion 50 may be in contact. Further, as the sealing devices 10B and 10C, an example where the second lip 52 is non-contact has been described, but the second lip 52 may be in contact.

[0106] In addition, in the embodiments described above, the first member 2 is the outer member and the second member 3 is the inner member, but the first member 2 may be the inner member and the second member 3 may be the outer member. That is, in that case, due to relative rotation, the lip portion 50 is in sliding contact with the contact target surface inside the outer member.

[0107] The sealing devices 10A to 10D regarding the various embodiments described above are merely examples. Also, it goes without saying that the overall shape of the sealing devices 10A to 10D can be appropriately changed to a shape other than the illustrated examples, for example, in accordance with the shape of the bearing device 1 to which it is attached, as a design matter.

[0108] Further, the sealing device in the present invention is not limited to being applied to a bearing device, and for example, it may be applied to an oil seal attached between a housing and a rotating shaft. Also, it is not limited to a shaft seal or an oil seal, and any seal for other uses may be used as long as it seals between a first member and a second member that rotate relative to each other and has a required conductive function.

Explanation of Reference Numerals

[0109] 1 Bearing device 2 First member 2a Fitting surface 2b Groove portion 3 Second member 3a Step portion 3b First surface 3c Second surface 5 Shaft 6 Sealed space 7 Rolling element 10A~10D Sealing device 20 Core material 20a First side 21 Cylindrical part 21a Second end 21b First end 22 Disk part 22a Inner end 20A Core material part 30 Conductive substrate 35 First extension piece 36 Second extension piece 40 Elastic material 41 Elastic part 41a End face 41b Out-corner part 41c Rib part 50 Lip part 51 First lip 52 Second lip 53 Third lip 50a End face 50b Out-corner part 60 Slinger 61 First cylindrical part 61a Outer peripheral surface 62 Disk part of slinger 63 Second cylindrical part 70 Molding die 71 First die (upper die) 71a, 71b Die ends 72 Second die (lower die) 72a, 72b Die ends

Claims

1. In an annular sealing device formed including an elastic material, which is mounted between a first member and a second member that rotate relative to each other, an elastic part made of the elastic material that contacts or is close to the first member, a lip part made of the elastic material that contacts or is close to a target surface on the second member side, and a conductive base material that enables auxiliary electrical connection between the first member and the second member, a sealing device, characterized in that a first extension piece formed of a part of the conductive base material protrudes so as to contact the target surface on the second member side from the lip part.

2. In Claim 1, the first extension piece protrudes from an end surface of the lip part, and the end surface is a facing surface facing the second member, the sealing device being characterized thereby.

3. In Claim 1, further configured to include an annular core material having higher rigidity than the conductive base material, the core material including a cylindrical part extending in the axial direction and a disk part extending in the radial direction from one end of the cylindrical part, the conductive base material being arranged to contact at least one of the disk part and the cylindrical part and being sandwiched between the core material and the elastic material, the sealing device being characterized thereby.

4. In Claim 1, in a state of being mounted between the first member and the second member, the lip part is non-contact with the target surface, while the first extension piece is in contact with the target surface, the sealing device being characterized thereby.

5. In Claim 1, a second extension piece formed of a part of the conductive base material protrudes from an end surface of the elastic part so as to contact the first member, the sealing device being characterized thereby.

6. In Claim 1, the conductive base material is a metal mesh material formed by braiding metal fine wires, and the elastic material is impregnated and fixed in the metal mesh material, the sealing device being characterized thereby.

7. A bearing device, characterized in that the sealing device of Claim 1 is mounted between an outer ring as the first member and an inner ring as the second member.

8. In a manufacturing method of a sealing device, the sealing device according to Claims 1 to 6 is molded using a molding die including a first mold and a second mold. In a state where the first extension piece protrudes from the raw material of the elastic material, the raw material of the elastic material and the conductive base material are arranged in the molding die, and the first extension piece is sandwiched between the mold end of the first die and the mold end of the second die at one end of the outer diameter side and the inner diameter side of the molding die. A method for manufacturing a sealing device, characterized by comprising a molding preparation step.

9. In claim 8, The sealing device further includes a core material having higher rigidity than the conductive base material, After the execution of the molding preparation step, the raw material of the elastic material is compressed. A method for manufacturing a sealing device, characterized by this.

10. In claim 8, The sealing device is configured such that a second extension piece made of a part of the conductive base material protrudes so as to contact the first member from the end face of the elastic portion, In the molding preparation step, further, in a state where the second extension piece protrudes from the raw material of the elastic material, the first extension piece is sandwiched between the mold end of the first die and the mold end of the second die at the other end of the outer diameter side and the inner diameter side of the molding die. A method for manufacturing a sealing device, characterized by this.

11. In claim 8, The conductive base material is a metal mesh material formed by braiding metal fine wires. A method for manufacturing a sealing device, characterized by this.

12. In claim 8, After molding by the molding die, a part of the first extension piece in the molded article is cut and removed. A method for manufacturing a sealing device, characterized by this.

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